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Sensory and quality aspects of fresh-cut tomatoes as affected by stage of ripeness and postharvest treatment with 1-Meth...

University of Florida Institutional Repository

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SENSORY AND QUALITY ASPECTS OF FRESH-CUT TOMATOES AS AFFECTED BY STAGE OF RIPENESS AND POSTHARVEST TREATMENT WITH 1-METHYLCYCLOPROPENE (1-MCP) By MINNA LEIBOVITZ A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2003

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Copyright 2003 by Minna Leibovitz

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iii ACKNOWLEDGMENTS I would like to extend my gratitude Dr. Charles Sims. I could have never asked for a more wonderful major professor. He always took time out of his crammed schedule to discuss my project. His faith in my abilities as a student and a scientist encouraged me to pursue a master’s degree. I would also like to thank Dr. Talcott and Dr. Brecht for being wonderful mentors; and for their never-ending assistance and advice for my project. I would like to also thank Dr. Jeong for all of his help. I would like to thank all of my panelists for their dedication to tasting tomatoes. Without their help, there would not be a Chapter 4 or 5 to this thesis. I would especially like to thank my lab mates: Bryan, George, Kurt, and especially Rena. Rena is an amazing person. She helped out with my project even when she was juggling 12 million other things to do. She has become one of my closest friends, always there to listen or joke around. Without Rena, graduate school would not have been fun. I also appreciate all of the support I have received from my friends old and new. They have helped shape who I am, and made me more positive. They’ve also helped me learn to not take life so seriously and have a lot of fun. Last but not least, I’d like to thank my parents and my sisters for all of their support and encouragement. My parents provided the foundation to become well educated and successful, so I guess I’ll start working on that successful part. I would also like to thank Simon, for believing in me and keeping me grounded.

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iv TABLE OF CONTENTS Page ACKNOWLEDGMENTS.................................................................................................iii ABSTRACT....................................................................................................................... vi C HA P TER 1 INTRODUCTION........................................................................................................1 2 LITERATURE REVIEW.............................................................................................4 Structure and Composition...........................................................................................4 Physiology....................................................................................................................6 Postharvest Physiology.................................................................................................7 Tomato Quality...........................................................................................................10 Quality Requirements..........................................................................................10 Flavor Quality......................................................................................................10 Storage and Ripening Conditions...............................................................................12 Chilling Injury.....................................................................................................12 Ethylene and Chilling Injury...............................................................................14 Fresh-cut.....................................................................................................................1 6 Postharvest Treatments...............................................................................................19 Ethylene Blockers................................................................................................20 1-Methylcyclopropene.........................................................................................21 Postharvest Treatment of Climacteric Fruit with 1MCP...................................22 1-Methylcyclopropene and Nonclimacteric Commodities..................................24 3 MATERIALS AND METHODS...............................................................................26 Maturity Study............................................................................................................26 1-Methylcyclopropene study: Sliced Fruit Treatment................................................27 1-Methylcyclopropene study: Whole Fruit Treatment...............................................28 Quantitative Descriptive Analysis..............................................................................28 Quality Evaluation......................................................................................................30 Statistics..................................................................................................................... .31

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v 4 RESULTS AND DISCUSSION.................................................................................32 Study 1........................................................................................................................ 32 Light-red-stage Tomatoes: Replication 1............................................................32 Sensory results..............................................................................................32 Other quality attributes.................................................................................36 Red-stage Tomatoes: Replication 1.....................................................................38 Sensory results..............................................................................................38 Other quality attributes.................................................................................40 Light-red-stage Tomatoes: Replication 2............................................................42 Sensory results..............................................................................................42 Other quality attributes.................................................................................45 Red-stage Tomatoes: Replication 2.....................................................................45 Sensory results..............................................................................................45 Other quality attributes.................................................................................47 Light-red-stage Tomatoes: Replication 3............................................................49 Sensory results..............................................................................................49 Other quality attributes.................................................................................50 Microbiological results.................................................................................51 Red-stage Tomatoes: Replication 3.....................................................................51 Sensory results..............................................................................................51 Other quality attributes.................................................................................54 Microbiological results.................................................................................54 Study 2........................................................................................................................ 56 Light-red 1-MCP Treated Sliced Fruit vs. Control Fruit.....................................56 Sensory results..............................................................................................56 Other quality attributes.................................................................................57 Red 1-MCP Treated Sliced Fruit vs. Control Fruit.............................................57 Sensory results..............................................................................................57 Other quality attributes.................................................................................59 Study 3........................................................................................................................ 60 5 CONCLUSION...........................................................................................................65 LIST OF REFERENCES...................................................................................................67 BIOGRAPHICAL SKETCH.............................................................................................72

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vi Abstract of Thesis Presented to the Graduate School of the University of Florida in Partial Fulfillment of the Requirements for the Degree of Master of Science SENSORY AND QUALITY ASPECTS OF FRESH-CUT TOMATOES AS AFFECTED BY STAGE OF RIPENESS AND POSTHARVEST TREATMENT WITH 1-METHYLCYCLOPROPENE (1-MCP) By Minna Leibovitz August 2003 Chair: Charles Sims Major Department: Food Science and Human Nutrition Fresh-cut fruit products are partially prepared so that additional preparation is not necessary for consumption by the consumer. Fresh-cut fruit are sliced when ripe, so they are ready to eat with optimum color and flavor. This stage of development thus limits their shelf lives. Fresh-cut products are highly perishable, because processing damages the protective cells of the epidermis, making them vulnerable to discoloration, dehydration, and microbial invasion. After slicing tomatoes, there may be a loss of locular tissue, increase in water-soaked appearance, and deterioration, which hinders their marketing and acceptability. The ethylene inhibitor 1-methylcyclopropene (1-MCP) is effective in reducing the rate of ripening in many commodities such as apples, tomatoes, and avocadoes. Our objective was to compare the quality and sensory characteristics of light-red and red sliced fruit with whole fruit controls and slices treated with 1-MCP.

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vii The stage of development affects the quality of fresh-cut fruit. Sliced light-red and red-stage tomatoes stored at 2C were compared to whole fruit controls at 2C and 12C over a period of 7-10 days. In both stages of development, sliced fruit displayed increased water-soaked appearance and a loss in overall flavor intensity compared to whole controls. Red-stage slices typically had better initial quality, but shorter shelf-lives than light-red-stage slices. Slicing tomatoes leads to increased ethylene production and respiratory activity; consequently causing changes in quality. Light-red and red-stage fresh-cut tomatoes were treated with 1 ppm 1-MCP at 5C for 24 hours to determine whether quality would be extended. Sensory panel results concluded that overall there were no major differences between control slices and 1-MCP-treated slices over a period of 7 days. Differences between ripeness stages were more evident in attributes such as red color intensity, watersoaked appearance, and firmness. The physiology of sliced fruit differs from whole fruit. Whole red-stage tomatoes were treated with 1 ppm 1-MCP at 20C for 24 hours, then sliced to determine whether application of 1-MCP before slicing would be more effective in extending the shelf life of sliced tomatoes. Panelists determined that control fruit had a less water-soaked appearance than 1-MCP-treated fruit on Day 6 of storage and less fresh tomato aroma. Overall, application of 1-MCP to whole fruit before slicing did not have a major impact on the quality of sliced fruit throughout storage.

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1 CHAPTER 1 INTRODUCTION Fresh-cut fruits and vegetables are a growing part of the food industry. These products are popular because of their convenience. Currently, there is great success in marketing fresh-cut vegetables; and now the goal is to open the market to more fresh-cut fruits. Watermelon, kiwifruit, and pineapple are already very successful as fresh-cut items. However, complex physiological and biological changes occur when fruit are sliced and stored (Watada et al.1996), limiting the growth and quality of the fresh-cut fruit. Fresh-cut fruits are more perishable than intact products because they have been subjected to severe physical stress, such as peeling, cutting, and slicing, which causes damage or removal of epidermal cells and wounding (Watada et al. 1996). This also can increase susceptibility to invasion by pathogens, Fresh-cut products are held at low temperatures (0-10C) to inhibit pathogenic growth. More than 60 million tons of tomatoes are produced in the world each year. Popularity and health benefits associated with tomatoes make them a viable commodity for fresh-cut. According to a recent report in the Journal of the National Cancer Institute (Giovannucci 1999) consuming tomatoes and tomato-based products reduced the risk of cancer at a defined anatomic site, perhaps because of lycopene, an antioxidative pigment found in tomatoes. The strongest evidence was for protection against cancer of the prostate, lung and stomach; though there was evidence of benefit for the pancreas, colon, rectum, esophagus, oral cavity, breast, and cervix (Giovannucci 1999).

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2 Officials at McDonald’s Corporation announced that by the end of 2002, each of their 13,000 U.S. stores will have the ability to purchase fresh-cut tomato slices from suppliers rather than cutting them in-house (Stedman 2002). Purchasing pre-sliced tomatoes would alleviate the managers’ responsibility to decide when the fruit was ripe enough to slice and serve to customers; and would hopefully improve product quality. Tomatoes are climacteric fruit that ripen in response to ethylene and show a characteristic rise in respiratory rate before the ripening phase Stress factors (such as wounding, flooding, chilling, disease, high temperatures and drought) seem to induce ethylene synthesis, thus increasing the rate of ripening and senescence (Wang 1990). When sliced, tomatoes elicit a wounding response. Wounding causes a surge in the production of ethylene (Gil et al. 2001), which in turn causes the fruit to ripen faster. Slicing also causes juice accumulation and microbial growth. Although shelf life can be extended by cold storage, tomato tissue is sensitive to chilling injury. Chilling injury is the physiological disorder caused by exposure of plants to low, nonfreezing temperatures (Wang 1990). The symptoms of chilling injury in tomato fruit are uneven ripening, surface pitting, increased susceptibility to fungal infection, loss of aroma volatiles, and water-soaked areas on red tomato fruit (Hong and Gross 2001). Although storing fruit at low temperatures causes chilling injury, chill-sensitive fruits should be held at a temperature at which injury from chilling will be of less consequence than the deterioration that results at non-chilling temperature (Watada et al. 1996). So far, not much research has investigated the quality and stability of fresh-cut tomatoes over storage. A valuable parameter to consider with fresh-cut tomatoes is slicing at an earlier ripeness stage; and investigating effects on quality. Also, slowing the

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3 ripening process and inhibiting chilling injury are possible ways to extend shelf life and quality of fresh-cut tomatoes. 1-methylcyclopropene (1-MCP) has been found to inhibit the actions of ethylene; and extend the storage life of many intact fruits and vegetables such as plums, apples, and tomatoes (Blankenship and Dole 2003). The possible effects of 1-MCP on the sensory quality and acceptability of fresh-cut tomato slices are of great interest to the fresh-cut industry.

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4 CHAPTER 2 LITERATURE REVIEW Tomatoes are one of the most important commodities in America. According to the Florida Tomato Committee (2001), the per capita consumption of fresh tomatoes in the United States is approximately 17.7 lbs per year. Fresh tomatoes ranked number three in consumer preference of vegetables, exceeded only by potatoes and lettuce. During the 2000-2001 season, Florida growers harvested over 35,000 acres of tomatoes for the fresh tomato market. Florida shipped in interstate commerce over 1.34 billion pounds of tomatoes. At the farm level, Florida tomatoes were valued at about $490 million. The farm value of the tomato crop in Florida represents more than 29% of the total value of all fresh vegetables produced in Florida each season. The total cost of producing and harvesting tomatoes averages more than $11,600 per acre. Florida produces almost all of the fresh-market field-grown tomatoes in the United States from December through May each year (Florida Tomato Committee, 2001). Structure and Composition Characteristics of tomato fruit differ among the many tomato varieties. The tomato is a berry with 2 to 12 locules filled with many seeds (Jones 1999). Processing tomatoes (such as cherry, plum, or pear tomatoes) have two locules. Commercial cultivars for fresh market have four to six locules. Large beefsteak-type tomatoes have more than six locules. The extent of pollination affects the size and shape of the fruit, which determines the number of seeds filling each locule (Jones 1999).

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5 Water comprises 90% of the fresh weight of tomato fruit; and the size of the fruit is influenced by the availability of water to the plant. The large amount of water also makes the fruit perishable. As the tomato fruit develops, the percentage of fresh weight that is sucrose decreases; while carbohydrates such as starch and reducing sugars increase (Jones 1999). Sugars are mostly found in ripe fruit; and starches are found mostly in unripe fruit (Wills 1981). In a ripe tomato fruit, about 5-7% of the tomato fruit is solids. About half of the solids comprise sugars and one eighth is acids (Jones 1999). The main sugar in tomatoes is glucose. Citric acid is the main acid in tomato juice; and the pH of fruit is normally between 4.0 and 4.5 (Jones 1999). The pH of the fruit increases throughout development. Growing plant cells are surrounded by a primary wall made of polysaccharide. The plant cell wall is a complex matrix containing cellulose, hemicelluloses, pectin, structural proteins, and other components. The primary wall has many functions that provide support and information to the plant. The primary cell wall is the source of many biologically active signaling molecules (Noogle and Fritz 1983). These molecules are used to determine downstream phenotypic expression of the plant. As well as being popular with consumers, tomatoes are also highly nutritious. One medium tomato provides 40% of the US RDA of vitamin C and 20% of the US RDA of vitamin A, which comes from carotene (Jones 1999). Tomatoes were ranked highest in a comparison of crops and their contribution of nutrients to the diet (Wills 1981). Tomatoes also provide potassium, iron, phosphorus, and some B vitamins, and are a good source of dietary fiber. Ripe tomatoes are red in color because they contain lycopene, an antioxidant.

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6 Lycopene is a pigment synthesized by plants and microorganisms. Its singletoxygen-quenching ability is twice as high as that of beta-carotene and 10 times higher than that of alpha-tocopherol (Rao and Agarwal 1999). In a review discussing studies of tomato lycopene and the incidence of prostate cancer risk, some studies have found a lower incidence of prostate cancer in populations that consume large amounts of tomatoes and tomato products. Consuming tomatoes and tomato products may decrease the risk for developing prostate cancer (Rao and Agarwal 1999). Studies suggest that lycopene from various tomato products is indeed associated with the lowered risk of several types of cancers (Rao and Agarwal 1999). In epidemiological studies correlating the incidence of cancer with the consumption of some tomato products, it appeared that the intake of tomato products was inversely associated with prostate cancer, and a high tomato intake resulted in reduced risk of digestive tract cancer (Bramley 2000). But, the connection of diets high in lycopene with the reduction of chronic diseases may be misleading because lycopene may not be the only anticancer compound in tomatoes (Bramley 2000). More studies need to be completed before anything definitive is stated concerning dietary intake of lycopene and lowered risks of cancers. Physiology Fruits and vegetables have three physiological stages following initiation or germination: growth, maturation, and senescence (Wills 1981). During growth and maturation, the fruit is still attached to the plant. The growth period is the time when cell division and enlargement take place, which is responsible for the final size of the produce. Irreversible increases in physical attributes of a plant or plant organ occur during growth (Watada et al. 1984). Another period of development for the plant is the

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7 maturation period. It is during this period that the commodity develops characteristics to obtain physiological and horticultural maturity. Physiological maturity is the stage of development when a plant or plant part will complete ontogeny even when not attached (Watada et al. 1984). A mature green tomato is considered physiologically mature; it can be harvested and continue its lifecycle. Horticultural maturity is the stage of development when a plant or plant part possesses the quality characteristics for utilization by consumers (Watada et al. 1984). For tomatoes, the horticultural maturity can range from mature green through full ripe depending on the purpose of use (Sargent and Moretti 2002). In order to obtain horticultural maturity for some commodities, salad and sandwich tomatoes, it is necessary for the fruit to ripen. Postharvest Physiology The tomato is a climacteric fruit. Shortly before they begin ripening, climacteric fruits experience a sharp rise in respiratory rates. At the beginning of ripening, tomatoes experience a surge in respiration, shown with an increase in the production and release of CO2 and ethylene, which peaks at about 10 days, and then declines (Jones 1999). In tomatoes, the climacteric peak is reached before there is an appreciable accumulation of lycopene, and when the red pigment accumulates, the rate of respiration decreases (Thimann 1980). Climacteric fruit should be considered fully ripe after they reach their respiratory climacteric (Wills 1981). Ripening is the aggregation of processes that occur from the growth and maturation stages of development through the early stages of senescence. Ripening changes are set off and synchronized by a synthesis and sensitivity toward ethylene (Hobson 1987). It is during this period that the esthetic and quality characteristics as expressed by the fruit.

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8 Fruit ripening is a gradual process during which a fruit attains optimal eating quality (Nevins and Jones 1987). In tomato, the process is characterized by the breakdown of chlorophylls and the synthesis of lycopene, as well as increases in sensitivity to ethylene, ethylene production, respiration, and the activity of polygalacturonase (Nevins and Jones 1987). Respiration and generation of ethylene increases with a peak at about 10 days and then declines (Jones 1999). When tomatoes ripen, they also soften. This is caused by changes in the structure and composition of their cell wall. Cells of fruit can be large parenchymatous cells with large air spaces between them (Thimann 1980). Changes in intensity of contact between cells and structure of cell walls will affect texture (Thimann 1980). During ripening, cell turgor is lost, middle lamella intercellular cement is broken down, and the cell walls are thinned (Hobson 1987). Many enzymes have been linked with cell wall weakening, such as polygalacturonase (PG). Their activity is low or absent in unripe fruit and increases during fruit ripening. In tomatoes, PG is found in the form of endoPG. Endo-PG cleaves the chains of polyuronides randomly. An increased solubility of cell wall polyuronides occurs during softening in many fruits (Noogle and Fritz 1983). There are six stages of tomato fruit development during ripening (for red fruited cultivars): mature green, breaker, turning, pink, light-red, and red. Fruit change from green to red, due to the conversion of chloroplasts, which contain chlorophyll to chromoplasts, which have red or yellow carotenoids (Thimann 1980). Fruit are mostly picked at the breaker stage of development, characterized by fruit, which are mostly green, but showing pink color at the blossom end, and the placenta is pinkish in the fruit.

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9 At this stage, fruit are still very firm, which makes them ideal for shipment. Mature green fruit, which is picked prior to breaker stage, have a very long shelf life, but these less mature fruit result in a significant loss in color and flavor when the fruit ripen (Jones 1999) compared to fruit that are left on the plant for longer prior to harvest. Mature green and breaker stage tomatoes are usually ripened at 20 C, and can be accelerated by treatment with 100-150 ppm ethylene. Ethylene treatment shortens the time after harvest required to bring about the climacteric rise affecting the respiration rate at the climacteric peak (Thimann 1980). Ethylene-treated mature green tomato fruit will develop red color at 5-7 days at 18-20 C (Jones 1999). Ripening is considered to start during the end of maturation, and the beginning of senescence (Wills 1981), during which the structure and the composition of unripe fruit change so that it will become acceptable to eat (Thimann 1980). Ripening and senescence, the final stages of development for tomatoes, may occur on or off the plant. Senescence is defined as the period when anabolic biochemical processes are replaced with catabolic processes, which lead to aging and death of the tissue (Wills 1981), when fruit are beyond ripe and breakdown and decay begin (Jones 1999). A major structural change that occurs during ripening is the degradation of polyuronides by (PG), resulting in a loss of galacturonic acid residues from the cell wall (Stommel and Gross 2001). A net loss of arabinose and galactose residues also occurs from cell walls of ripening fruit. Numerous lines of evidence support a role for PG in the fruit ripening process give a loss of fruit integrity during senescence (Stommel and Gross 2001).

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10 Tomato Quality Quality Requirements There are many key points to be considered in assessing the quality of tomatoes. The minimum quality requirements for tomatoes after preparation and packaging include: intact, fresh-looking, clean, free of excessive moisture, sound, and free of any foreign smell and/or taste (Sargent and Moretti 2002). Also, the development and condition of the tomatoes must enable them to withstand transport and handling, as well as arrive in satisfactory condition in the place of destination. High quality fruit have a firm appearance, uniform and shiny color, without signs of injury, shriveling, or decay (Sargent and Moretti 2002). Tomatoes must also be packed in such a way that they are protected properly. The materials used inside the package must be new, clean, and of a quality such as to avoid causing external or internal damage to the produce. Physical attributes are used to assess quality in fresh, vine-ripened tomatoes. Stem and blossom scars, shoulders, color, and skin are all quality indicators (Hodges 1997). The blossom scar should be small and tight, and the shoulders should be smooth and round and the stem scar should be small and smooth. The color of the tomato should be uniform with no blotchiness or scarring and fruit locules should be filled with gel, not air spaces. Any deviation from the above physical descriptions can be a sign that the fruit has been exposed to stress such as improper temperature storage (Hodges 1997). Fruit quality is affected by ripeness stage, time of removal from plant, handling conditions and frequency, and storage temperature and time (Jones 1999). Flavor Quality Fruit and vegetable flavor is the function of taste and aroma components (Jones 1999). The relationship between the acidity and soluble solids of tomato fruit is critical to

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11 its perceived flavor (Jones 1999). Flavor quality is also affected by the stage of ripeness; the stage at which harvest occurs has a major impact on the final flavor quality of the tomatoes (Jones 1999) Fruit that remain attached to the plant longer are generally more flavorful. Harvest maturity, storage temperatures, and internal bruising all negatively affect tomato flavor and quality (Sargent 1997). Malundo et al. (1995) found that taste (sweetness and sourness) and acceptability of tomatoes was greatly affected by sugar and acid levels. The study also found that sugar and acid concentrations did not significantly influence descriptive ratings for fresh tomato impact. Tomatoes that had a pH of 3.74 and 0.80% titratable acidity had improved flavor quality based on consumer acceptability ratings, when sugars were added. Also, consumer acceptability ratings tended to decrease with added acid at a given sugar concentration (Malundo et al. 1995). Sensory characteristics of short-term stored tomatoes were evaluated by a trained panel using Quantitative Descriptive Analysis. The study assessed 57 attributes and consumer preferences in eight categories (Auerswald et al. 1999). Tomatoes stored for 4 or 7 days differed from fresh tomatoes in intensity of attributes (such as appearance of outer and inner fruit, firmness to touch, smell, flavor aftertaste, and mouthfeel). Increases in aroma attributes “tomato-like” and “sweetish” were found. Flavor attributes “sweet” and “tomato-like” increased, as did off-flavor attributes “moldy” and “spoiled sweetish.” Sour and fresh-cut grass characteristics decreased. The trained panel found that with increased postharvest storage period, the fruit were softer, juicier, pulpier, and less “grainy” and “gristly.” Consumers could tell a difference between the characteristics of fresh and stored fruit on first impression, appearance, and smell. Surprisingly, the

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12 appearance and smell of stored tomatoes were rated higher than fresh tomatoes (Auerswald et al. 1999). Storage and Ripening Conditions Tomatoes for fresh consumption are commonly harvested at the immature or mature green stages and shipped to retailers under controlled conditions, allowing long distance shipment (Boukobza and Taylor 2002). Tomatoes should not be stored at temperatures below 12 C, according to the Florida Tomato Commission, whereby “refrigeration kills aroma and flavor in fresh tomatoes (2001).” After commercial packaging, tomatoes are placed on pallets and are either cooled at 20 C for ripening, or 12 C for storage. Optimum storage conditions depend on the maturity stage of tomatoes. For ripening, optimum storage is 19-21 C. Tomatoes ripened at temperatures higher than 27 C have reduced intensity of red color development, while temperatures less than 13 C impede ripening and may lead to symptoms of chilling injury (Sargent and Moretti 2002). Chilling Injury Chilling injury is the physiological damage that occurs in many plants and plant products of tropical or subtropical origin when exposed to low, but not freezing temperatures (Wang 1990). Exposure to such low temperatures has been shown to inhibit photosynthesis, growth, pollination, fruit set, and fruit development (Lurie and Sabehat 1997). Fundamental qualities of fruit tissue, such as species, cultivars, growing conditions, age, maturity, and exposure to stress all contribute to the development of chilling injury symptoms; environmental conditions, such as temperature, duration of exposure, relative humidity, and postharvest treatments also determine the intensity of symptoms (Wang 1990). Chilling injury occurs in many fruit, including avocado,

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13 pineapple, as well as tomato. The symptoms of chilling injury occur based on time and temperature of exposure (Wang 1990). Uneven ripening, surface pitting, and increased susceptibility to fungal infection, loss of aroma volatiles, and water-soaked areas on the fruit surface are symptoms of chilling injury in tomato fruit. Chilling injury causes the release of amino acids, sugars, and salts, which provide food for the growth of pathogens, such as fungi, and may take the form of rotting in the fruit flesh (Wills 1981). Off flavors and off odors are also characteristic of chill injured fruit. Chill injured fruit softening may be related to changes that occur during their storage and possibly lead to mealy texture (Palma et al. 1995). Mature green tomato fruit kept at a sufficiently long time at 12.7 C or colder will have poor color when ripe, and alternaria rot (Lorenz and Maynard 1988). Ripe fruit kept colder than 7 C will exhibit water soaking and softening decay (Lorenz and Maynard 1988). Generally, greater chilling injury occurs to fruit that are exposed to lower temperatures for longer periods of time (Wang 1990). Chilling injury symptoms usually form after the fruit is placed at a warmer, nonchilling temperature. The developmental stage is thought to influence plant sensitivity to chilling injury. Fruit at the preclimacteric stage is generally more susceptible to chilling injury than at the postclimacteric stage in fruit (such as avocado, papaya, melon, and tomato) (Wang 1990). Moline (1976) found that after 10 days mature green tomatoes stored at 0 C showed visible signs of chilling injury (Wang 1990), and Cook (1958) found that ripe tomatoes showed visible signs after 30 days under the same conditions. A storage temperature for chill sensitive fruit is chosen as one low enough to inhibit the ripening process and high enough to avoid chilling injury. For mature green whole tomato fruit, this temperature is 12 C, but ripening is not prevented at this

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14 temperature, so the fruit can only be held for 2 weeks (Lurie and Sabehat 1997). Low but nonchilling temperatures are commonly used to delay the onset of ripening in some commodities. These conditions delay the production of ethylene and decrease the sensitivity of fruit tissue to it. Tomatoes are stored at temperatures just above their chilling injury threshold with ventilation, so that there is no accumulation of ethylene. This allows the fruit to be transported for a longer period and ripened at a later time. Whole mature green tomato fruit were stored at 2 C for a period of 3 weeks to determine when the fruit would be sensitive to chilling injury. The study found that at during the first week, the tomatoes ripened as usual, but chilling injury symptoms were present after 11 days. Rots began to appear in post-storage ripening and color development was impaired (Lurie and Sabehat 1997). In a study of tomato fruit chilled for 10 days at 2 C, structural degradation was shown to have occurred over storage (Moline 1976). Plastids of the membranes had swollen, granal stacks deteriorated, and the internal lamellar tissues were distended. Also, mitochondria were swollen, cristae had begun to lyse, and small vacuoles had developed in the cytoplasm. All of these structural changes consequently caused loss of firmness. After 15 days, plastids of fruit had deteriorated, the mitochondria were swollen and cristae developed into vescicles. Fruit stored for 21 days at 2 C had very few organelles that were identifiable (Wang 1990), thus demonstrating that chill injury is detrimental to plant tissue. Ethylene and Chilling Injury Ethylene is produced through a signal transduction pathway. L-methionine is phosphorylated to S-Adenosylmethionine (SAM) through the activities of S-

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15 Adenosylmethionine synthase. SAM is then converted into 1-aminocyclopropane-1carboxylic acid (ACC) by ACC synthase. ACC Oxidase then catalyzes the production of ethylene from ACC. Formation of ACC is the rate limiting step in the production of ethylene (Noogle and Fritz 1983). The concentration of ethylene in plant tissue is dependent upon the rate of biosynthesis and on the diffusion of the gas (Noogle and Fritz 1983). Ethylene is neither “actively transported nor degraded” (Noogle and Fritz 1983). Activation of ACC synthase, from for example auxin or wounding, can initiate the production of ethylene. To inhibit the production of ethylene, breakdown or conversion of ethylene synthesizing enzymes, or precursors has been effective. ACC deaminase converts ACC to alphaketobutyrate, thereby preventing the formation of ethylene. Aminoethoxyvinyl glycine, or AVG, also inhibits ethylene synthesis and physiological responses caused by ethylene, such as chilling, wounding, and water-logging (Noogle and Fritz 1983). Ethylene has various effects on chilling injury of crops. In some fruit, ethylene treatment reduces chilling injury; in other fruit, it does the opposite. Ethylene treatment of mature green tomatoes before or after storage at chilling temperatures did not affect the development of chilling injury symptoms (Kader and Morris 1975). The effects of ethylene concentration on chilling injury of fresh-cut tomato have been investigated. Water-soaked areas on the fruit flesh have been used as an indicator for chilling injury in fresh-cut tomatoes (Hong and Gross 2000);(Gil et al. 2002). It has been proposed that water-soaked areas occur more closely to the blossom than the stem end of the fruit and may be related to differences in ripening stage (Gil et al. 2002). Tomato slices exposed to high concentrations of ethylene had less water-soaked areas

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16 than fruit stored in a low ethylene concentration environment (Gil et al. 2002), or slices that had been treated with AVG (Hong and Gross 2000). Fresh-cut International Fresh Produce Association (IFPA) has defined fresh-cut produce as “any fruit or vegetable or any combination thereof that has been physically altered from its original form, but remains in a fresh state”(2001). Fresh-cut fruits and vegetables are products that are partially prepared so that no additional preparation is necessary for use by the consumer. The food service industry was initially the main user of fresh-cut products, but supermarkets and warehouse stores have embraced them as well. Consumers perceive fresh-cut fruit as being healthy, tasty, convenient, and fresh (Center for Food Safety and Applied Nutrition ((CFSAN) 2001). The Fresh-cut industry has experienced growth over the past ten years. Consumption of fresh-cut products has increased, and spaces have been allocated in supermarkets for product placement (Calvin et al. 2001). Fresh-cut fruit are sliced when ripe so they are ready to eat with the optimum color and flavor levels acceptable to consumers. This stage of development consequently limits their shelflife. Ripe fruit are more susceptible to microbial contamination, but in ripe tomatoes, it has been found that high levels of polygalacturonase provided resistance to tomato anthracnose (Stommel and Gross 2001). Handling and processing of fruit can create the opportunity for cross contamination by foodborne pathogens. The fresh-cut industry must provide food safety protection systems, that ensure the protection of consumers from microbiological hazards (CFSAN, 2001), including implementation of Good Agricultural Practices (GAP’s), Good Manufacturing Practices (GMP’s), and Hazard Analysis Critical Control Points

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17 (HAACP). Usually, fresh-cut products are packaged in film packages or containers overwrapped with film (Watada and Qi 1999) and draw juice away from the fresh-cut item. Fresh-cut products are highly perishable because processing damages the protective cells of the epidermis, making them vulnerable to discoloration, dehydration, and microbial invasion (Watada, et al. 1996). Also, ethylene synthesis is induced in fruit that has been wounded (Hobson 1994), and may promote further ripening of the fruit. After processing tomatoes for fresh-cut, there is a loss of locular tissue, watersoaking, deterioration, and dessication, which hinders their marketing and acceptability (Sargent et al. 2001). Temperature, atmosphere, and relative humidity are all instrumental in keeping quality of fresh-cut products. Fresh-cut products differ in their shelflives. When held at their recommended temperature, they can last from 7 to 20 days depending on the commodity (Watada and Qi 1999). Fresh-cut products are held for a short period of time at a temperature that causes a slight amount of chilling damage, rather than a higher temperature causing a greater amount of natural deterioration (Watada and Qi 1999). For most fresh-cut fruits, including tomatoes, this temperature is around 5 C. Gil et al. (2002) reported that sliced tomatoes stored in modified atmosphere packaging had greater retention of quality up to 10 days when held at 0 C. There were no significant differences in slices held at 0 C or 5 C for up to 7 days (Gil et al. 2002). Gil et al. (2002) also found that in order to maintain quality of Fresh-cut tomato at 5 C over a period of 10 days, a low permeability film is required as well as an active MAP of 12 kPa O2 and 0 kPa Co2. They also found that use of ethylene absorbent pads did not improve shelf life of tomato slices over a 10-day storage period.

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18 O’Connor-Shaw et al. (1994) reported that fresh-cut honeydew and muskmelons should be held at the chilling temperature of 4 C because the amount of chilling injury was much less than the amount of natural deterioration that occurred at higher temperatures (Watada and Qi 1999). Zucchini slices held at 0 C had severe chilling injury after 17 days of storage; 50 % of zucchini slices held at 5 C had slight to moderate amounts of lesions and decay related to chilling injury after 16 days of storage. Ninety percent of samples held at 10 C had natural browning and decay by the twelfth day of storage (Izumi and Watada 1995) In a comparison of respiration rates of intact and fresh-cut products of several fruits and vegetables at 0, 5, 10, and 20 C (Watada et al. 1996), sliced fruit at “optimum edible maturity” had generally higher respiration rates than their whole fruit counterparts. Freshcut tomatoes had higher respiration rates than whole tomatoes at temperatures 5 C and greater, showing the increase in ripening. The study also showed that “at the non-chilling temperature, natural deterioration and infection by pathogens contributed more to deterioration of quality than any injury that may have resulted due to chilling”(Watada et al. 1996). The study concluded that chill sensitive fresh-cut fruits should be held at a chilling temperature where injury from chilling will be of less consequence than the deterioration that results at non-chilling temperatures. Fresh-cut fruits have a complicated physiology because ripeness stage and ethylene production reduces shelflife (Artes et al. 1999). In a study examining fresh-cut tomato quality at 2 C and 10 C, sliced tomatoes experienced an instantaneous, rise in CO2 production at 10 C (Artes et al. 1999). It was shown that at 2 C, partially ripe whole

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19 tomatoes had respiratory patterns similar to that of fresh-cut fruit, however the respiration of fresh-cut fruit increased significantly after 2 days at 10 C. Marketing of stored fresh-cut tomatoes has not been very successful because the fruit exhibits characteristics that compromise the quality and acceptability of the fruit after processing. The flesh becomes water-soaked, locular tissue is lost, and the fruit deteriorates. Tomato slices are also prone to water loss and softening (Artes et al. 1999). Destruction to the epidermis makes fresh-cut fruit more susceptible to microbial invasion. Chlorine solutions are used to prevent microbial inoculation, but are ineffective after pathogens have infected their host (Hong and Gross 1998). Fresh-cut products are usually rinsed in 50-200 ppm chlorine solutions (Watada et al. 1996). However, the chlorine solution does not eliminate all microorganisms and also can cause changes in texture. For example, fresh-cut spinach washed with 50 ppm chlorine contained mesophilic aerobic bacteria, psychrotrophic bacteria, Pserudomonadaceae Enterobacteriacae Vibrionaceae coliforms, and yeasts (Watada et al. 1996). Aqueous calcium dips have been used to improve firmness of fresh-cut pears, zucchini squash, and melon disks (Poovaviah 1986).Calcium reduces the action of cell wall degrading enzymes and improves cell wall structure, and lessening fruit softening (Poovaviah 1986). Postharvest Treatments In order for many climacteric fruit to be ripened properly, a controlled ripening treatment is used. Fruit are ripened to optimal quality under controlled conditions of temperature and relative humidity, with the addition of ethylene. Whole green tomatoes are kept at 20-21 C and continuously exposed to 10 ppm ethylene continuously until ripe.

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20 Another type of postharvest treatment is the application of ethylene blockers on commodities to further control fruit ripening. These ethylene blockers bind to the ethylene binding sites of fruits and inhibit the actions on ethylene. Many ethylene blockers have been tested in attempts to extend the time it takes to ripen the fruit. This could allow a longer transport period, and possibly delay ripening or decay in tomatoes and other fresh-cut commodities. Ethylene Blockers Some compounds have been found to bind to the ethylene receptor in plants, blocking ethylene action. This may be a new way of controlling ripening, senescence, and other ethylene responses (Sisler and Serek 1999). Other compounds such as cis-butene and cyclopentene were shown to inhibit ethylene action. It was found that highly strained cyclic olefins were more effective in blocking ethylene than less strained ones (Sisler and Serek 1999). These required continuous exposure to plant tissue to be effective (Sisler and Serek 1999). Some cyclic olefins seem to block ethylene responses in plants rather than induce a response. 2,5-norbornadiene (2,5-NBD) blocked at the lowest concentration, but all of the olefins tested required continuous exposure to be effective (Sisler and Serek 1999). The relative effectiveness of these compounds was found to be proportional to their ability to bind to silver ion, and ring strain was proposed to be an important factor in their effectiveness (Sisler and Serek 1999). It was found that some cyclopropenes counteract the effects of ethylene for 10-12 days in tissues given single exposure to the compounds at low concentrations (Sisler and Serek 1999); other cyclopropenes block for less time or seem to be inactive (Sisler and Serek 1999). Other compounds that are also effective ethylene inhibitors are carbon

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21 dioxide, silverthiosulfate (STS), 2,5-norbornadiene (2,5-NBD), and diazcyclopentadiene (DACP). 1-Methylcyclopropene 1-methylcyclopropene (1MCP) is an active organic compound that interacts with the ethylene receptor. It has ten times the affinity for the ethylene receptor than ethylene. 1-MCP is the breakdown product of DACP. For use on ornamental crops, Floralife, Inc. formulated a powder that releases 1-MCP when mixed with water. The product was approved by the EPA and is sold under the name Ethylbloc (Blankenship and Dole 2003). For commercial application for use on edible crops, 1MCP is applied under the trade name Smartfresh (Agrofresh, Inc). Methylcyclopropene “will probably be the ethylene inhibitor of choice for the immediate future and holds considerable commercial potential since its active concentration of 0.5 ppb on carnations has not been reported to have toxic properties” (Sisler and Serek 1999). Commodities are exposed to 1-MCP in its gaseous form. It is typically applied in minute concentrations to commodities as a fumigant in closed chambers at 20-25 C for 12-24 hour period. At standard temperature and pressure (STP), 1-MCP is released from Ethylbloc powder in approximately 20-30 minutes (Blankenship and Dole 2003). Temperature has shown to affect the time for 1-MCP to be completely released. In a sealed chamber, one third of the initial amount of the ethylene blocker remained in the chamber after 24 hours treatment at 5 C (Blankenship and Dole 2003). Various experiments have shown that there is a relationship between concentration, time, and temperature, and applications at low temperatures are not effective in some crops (Blankenship and Dole 2003). In coriander, 1MCP had no effect due to low sensitivity to ethylene at 5-10 C. In

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22 penstemon, application of 1MCP was not effective at 2 C, but at 20 C there was complete protection from exogenous ethylene (Blankenship and Dole 2003). This was also demonstrated in broccoli where 1-MCP application produced better results at 20 C than 5 C, although an effect occurred at both temperatures (Blankenship and Dole 2003);(Ku et al. 1999). The effective concentration of 1-MCP varies among commodities. In tomatoes, 7 ppb of 1-MCP blocked the color change for 8 days (Blankenship and Dole 2003); (Sisler et al, 1996). The extension of the postharvest life of ripe tomatoes required 2 ppm 1-MCP (Blankenship and Dole 2003). Postharvest Treatment of Climacteric Fruit with 1MCP In a summary of physiological processes or disorders in fruits, vegetables, and ornamentals that are affected or unaffected by exposure to 1-MCP, some climacteric fruit were investigated. Apples, apricots ,avocados ,bananas, plums ,and tomatoes had decreased ethylene production and respiration. Many of the fruits also maintained color and firmness nearer to the pretreatment levels. Softening is a problem associated with plums and apricots because they are picked at a partially early stage and undergo rapid ripening and overripening (Dong et al. 2002). Apricots can be divided based on their ethylene production (high, medium, and low). “Canino” apricots are in the medium category of ethylene production. Plums can be divided into two categories: 1) early rise in ethylene and CO2 production and 2) suppressed climacteric production (as cited in Dong et al. 2002). “Royal Zee” plums are in the latter. “Royal Zee” plums treated with 1 ppm 1-MCP retained most of their firmness compared to control fruit at 5, 10, and 30 day storage times. However, after

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23 storage, during the ripening period at 20 C, the difference decreased and reached the same level at 12 days. Canino apricots treated with 1ppm 1MCP did not experience differences in firmness during storage period, but there were textural differences between treatments during the ripening period. Therefore proper fruit maturity must be carefully chosen for 1-MCP treatment (Dong et al. 2002). Tomatoes are harvested early to reduce damage during transport, and then are allowed to ripen. Ripening of green tomatoes is sped up by exposure to ethylene. Mature green clarion tomatoes treated with various concentrations of 1-MCP at 20 C showed a delay in ripening relative to concentration of treatment over time (Wills and Ku 2002). Green tomatoes treated with 1-MCP also showed a decrease in brix/acid ratio compared to control fruits. 1-MCP also resulted in a reduction in respiration of mature green tomatoes in the first 6-8 days after treatment, but inhibited the loss of titratable acidity throughout the storage period. The results of the study suggests that 1-MCP treated tomatoes might be more acceptable since their initial acid level remained the same throughout storage but could not be investigated further due to the lack of registration of the treatment at the time of the study (Wills and Ku 2002). Apples also respond to the effects of 1-MCP. 1-MCP has also been shown to delay ripening of apples (Baritelle et al. 2001), as well as improve their textural quality (DeEll et al. 2001). The effects of 1-MCP on apples are dependent on duration and temperature of treatment. “Empire” apples treated for only three hours showed initial improvement in firmness retention, but after additional storage at 20 C, their firmness did not differ from control fruit (DeEll et al. 2001).

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24 1-Methylcyclopropene and Nonclimacteric Commodities Chilling injury is known to be associated with ethylene synthesis, even in nonclimacteric fruit (Selvarajah 2001). Pineapples, grapefruit, and oranges are examples of nonclimacteric fruit. A postharvest application of 1 ppm 1-methylcyclopropene at 20 C for 18 hours on "Queen" pineapples that were stored at 10 C for 3 weeks resulted in minimal internal browning, and delayed shell ripening (Selvarajah 2001). Color change and decrease in shelf life are also associated with ethylene exposure in minimally processed nonclimacteric leafy Asian vegetables, such as Chinese mustard and choy sum. These leaves experience senescence quickly because they lack ability to obtain nutrients from other parts of the plant (Able et al. 2003). The presence of ethylene may also enhance yellowing, an undesirable characteristic to the consumer. Application of 1-MCP increased shelf life of mizuna and tatsoi (shown by a decrease in the color), and also decreased browning in mizuna (Able et al. 2003). It has been shown that ethylene has a part in the senescence of detached leaves. Coriander leaves treated with .5 ppm or higher 1-MCP at 20 C for 24 hours experienced an inhibition in the loss of chlorophyll and soluble protein in the leaves and ethylene production was increased with the treatment (Jiang et al. 2002). Strawberries are nonclimacteric fruit that also respond to ethylene. Strawberries exposed to ethylene have been shown to develop more red color intensity than those stored in ethylene free air (Jiang et al. 2001). Strawberries treated with 1-MCP have delayed rotting (Ku et al. 1999) and delayed changes in firmness (Jiang et al. 2001). Overall, 1-MCP has shown to be an important application is extending the shelf life of climacteric and non-climacteric whole fruit.

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25 The objectives of this study are to determine how stage of ripeness affects the sensory quality as well as shelf life of fresh-cut tomatoes, as well as determine whether 1MCP is a valuable postharvest treatment for extending the shelf life of fresh-cut tomatoes.

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26 CHAPTER 3 MATERIALS AND METHODS Maturity Study Pink stage “Florida 47” tomatoes were received from a packinghouse in Palmetto, Florida and tomatoes were placed in a 20 C cooler for ripening. After 2 days of storage at 20 C, tomatoes were sorted based on color, indicative of ripeness stage. Ninety light-red tomatoes were chosen based on their quality (skin color and firmness) and were further separated into 3 groups: 2 C whole fruit control (30), 12 C whole fruit control (30), and 2 C sliced (30). Control fruit storage temperatures were chosen as a representative of whole fruit stored at chill injury temperature (2C) as well as fruit at the threshold chill injury temperature(12C). Sensory results showing similarities in attributes of sliced fruit with whole fruit controls stored at 2C were indicative of chill injury symptoms, and similarities of sliced fruit with whole fruit controls at 12C were indicative of senescent responses of the sliced fruit. Tomatoes were rinsed with a 100 ppm NaOCL and left to air dry. The whole fruit controls were placed on sanitized trays at their respective temperatures in humiditycontrolled coolers. The third group of tomatoes was sliced at 20C using a sanitized Tomato Saber (Prince Castle Inc. Part Number943 004. Model Number(943). Slices were approximately 1/2 inch in width. After slicing, the tomatoes were placed in sanitized TupperwareTM Fridgesmart Containers individually. Both ventilation holes were left open on the body of the container. The containers were then placed in a cooler

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27 at 2 C. Quality and sensory characteristics were assessed at 2-3 day intervals. Whole fruit controls were sliced upon evaluation. The procedure was repeated for red-stage tomatoes after they had ripened at 20 C 3 days after the light-red-stage samples were initially stored. All samples were stored for a period of 6 days. The study was repeated two additional times. During the second replication, “Florida 47” tomatoes were shipped from Quincy, FL to a Publix supermarket in Gainesville, FL. Light-red-stage tomatoes were stored for a total of 10 days, and the red tomatoes were stored for 6 days. During the third replication, “Mountain Spring” tomatoes were shipped from Alabama to a Publix supermarket in Gainesville, FL. Both light-red and red-stage tomatoes were stored for 10 days. 1-Methylcyclopropene study: Sliced Fruit Treatment Light-red-stage premium “Florida 47” tomatoes were received from Publix Supermarkets in Gainesville, FL. Thirty tomatoes were sorted based on physical quality, as described above, and rinsed in a 100 ppm sodium hypochlorite solution and left to air dry. Tomatoes were then placed at 5 C for overnight storage to avoid cold shock. After storage, the tomatoes were sliced using a sanitized Tomato Saber, and placed in sanitized Fridgesmart containers individually. Both ventilation holes were left open, and then placed in a sanitized sealed chamber at 5 C. The treatment group was also sliced and placed into Fridgesmart containers in a chamber at 5 C. A 1 ppm solution of 1-MCP was dispersed in the chamber and the chamber was then sealed. After 12 hours, the control chamber was opened for approximately 1 minute, and then resealed. The treatment chamber was also opened and another 1 ppm solution of 1MCP was dispersed, then the chamber was resealed. After the total treatment time of 24 hours

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28 completed, samples were taken out of the chamber and were stored at 5 C for 7 days. Samples were evaluated every 2-3 days for quality characteristics. The study was repeated with the addition of the red-stage of maturity, evaluation by the trained panel, and microbial counts were measured. 1-Methylcyclopropene study: Whole Fruit Treatment Red-stage “Florida 47” tomatoes were delivered from a packinghouse in Florida to Gainesville, FL via Publix Supermarkets. Samples were sorted based physical quality. Tomatoes were then separated into two groups (control group no 1-MCP treatment and treatment group1-MCP treatment at 1 ppm for 24 hours), placed into chambers, and treated as described in above section for sliced tomato MCP fruit. After treatment period, samples were sliced and placed in 5 C. A trained sensory panel evaluated samples and microbial plate counts were completed every 2-3 days. Quantitative Descriptive Analysis A fifteen-member panel, made up of faculty and students of the University of Florida, was trained for sensory analysis of tomato slices. Panelists were selected based on their ability to distinguish between stored and fresh tomato slices and their availability during the study. In the first training session, panelists were given samples and chose descriptor terms necessary to evaluate tomato quality. In the second training, panelists were instructed on evaluating samples using a line scale and were presented with more tomato samples at various ripeness levels. During the third through eighth trainings, panelists were presented with standards of fresh and stored tomatoes for 13 attributes: red color intensity, water-soaked appearance, fresh tomato aroma, off odors, firmness, juiciness,

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29 mealiness, overall flavor intensity, overall ripe tomato flavor, off flavors, acidity, sweetness, and overall acceptability. Panelists compared samples with standards on the line scale. Different ripeness levels of tomatoes were used as standards of red color intensity. Vine ripe tomatoes and red-stage premium tomatoes were used as an anchor for high overall ripe tomato flavor. Fresh sliced tomatoes and tomatoes stored for 3,5, and 10 days were used as standards for various levels of fresh tomato aroma, off-odors, off flavor, and overall flavor intensity, with fresh tomatoes as the high anchor for fresh tomato aroma. Sliced tomatoes stored for 21 days at 2C were used as the high anchor for water-soaked appearance and off odors. Yellow and mature green tomatoes were used as examples of low acidity, and cherry tomatoes were used as examples of high acidity and juiciness. Grape tomatoes were used as examples for sweetness. Also, peaches and watermelons were used as examples of mealiness. During the ninth training, panelists were taught how to rate samples using Compusense™ software (Compusense Inc. Ontario, Canada. Version 5.4). In subsequent trainings between studies, panelists evaluated, and discussed samples at different ripeness and storage levels as a refresher. Panelists evaluated samples in individual booths at the sensory facility at the University of Florida. The five middle slices of tomatoes were used for evaluation. The stem and blossom ends of the tomato were discarded. Each panelist was given three halfslices of tomatoes per sample. Panelists had slices from three different tomatoes in each sample. Samples were placed side by side on trays in individual cups closed with lids. Panelists were presented samples in random order for evaluation. The samples were evaluated in duplicate. Between replications, panelists took a break to reduce fatigue.

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30 Quality Evaluation Prior to sensory evaluation, color and texture of slices were measured. There were five samples per treatment group of color and texture. Color (reflectance) was determined using a Minolta Colorimeter (Chromameter CR 200b) and was expressed in L, a and b, and converted into Hue values: (tan-1 (b/a)). Color was measured on the fourth slice on the pericarp tissue. Slices from three different samples were taken for each treatment in triplicate. Texture was determined using the Instron Universal Testing Instrument with a compression test and a number nine probe. Texture was expressed as maximum force used to compress sample 0.25 mm. Texture was measured also on the fourth slice, and was repeated in triplicate. Slices from four different samples were taken for each treatment group. After sensory evaluation, remaining samples were homogenized for determination of pH, titratable acidity, and soluble solids. pH measured on approximately 40 mL of homogenate using a Fischer Scientific pH meter (Accumet Basic AB15) in triplicate. Titratable acidity, expressed as percent citric acid was also determined using the Fischer Scientific pH meter using 0.1N NaOH to titrate a 10 g homogenate per 90 mL distilled water solution to a pH of 8.2. Percent soluble solids, expressed as degrees brix ( B) was determined using a refractometer (Abbe Refractometer Mark II. Model 10480). Aerobic and yeast and mold plate counts were completed through use of aseptic technique. Three individual slices per treatment from different tomatoes were weighed and mixed with sterile phosphate buffer in sterile sample bags to obtain a 10:1 dilution. Samples were stomached and then plated onto 3M Petrifilm for aerobic bacteria, and yeasts and molds, respectively. Samples were then serially diluted until 10-7. Samples were plated every 2-3 days of storage.

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31 Statistics All results were analyzed using analysis of variance on SAS statistical Software (Version 8.2) Data was sorted by time and by treatment separately. Maturity levels were analyzed independently of each other. After analysis of variance was completed and significance between treatments was found (0.05), a Duncan’s Multiple Range Test was used for mean separation.

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32 CHAPTER 4 RESULTS AND DISCUSSION Study 1 Light-red-stage Tomatoes: Replication 1 Sensory results Light-red-stage “Florida 47” tomatoes were sliced and held at 2 C (2SLI) for 6 days. Whole tomatoes were also stored at 2 C (2W) and 12 C (12W) for 6 days. After the designated storage period, whole samples were sliced and all treatments were evaluated. Panelists evaluated treatments for 12 attributes: red color intensity, fresh tomato aroma, off odors, firmness, mealiness, juiciness, overall flavor intensity, overall ripe tomato flavor, off flavor, acidity, sweetness, and overall acceptability. As shown in Table 1, many sensory attributes of the light-red-stage “Florida 47” tomatoes had varied responses between treatments (2 C whole, 12 C whole, and 2 C sliced) and over time (0-6 days). For most attributes, differences between treatments occurred only at Day 6 of storage. For red color intensity, there was no difference between samples until Day 6. The 2 C control as well as the sliced fruit had less red color intensity than the whole fruit held at 12 C. This indicates that the fruit at the holding temperature of 12 C developed red color over time, as an effect of normal ripening. During the first replication, there was an increase in the water-soaked appearance of the slices, which decreased the red color intensity of the sliced fruit. In subsequent replications, the attribute “water-soaked appearance” was added.

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33 There were no differences between treatments and throughout storage for fresh tomato aroma. Fresh tomato aroma was maintained at a score of approximately 8.5 throughout storage. For off odor, there were no differences between treatments throughout storage, but over time, the off odors did increase slightly for all samples. Sliced fruit were lower in firmness compared to the whole controls by Day 3, and over time, all samples experienced a decline in firmness. This indicates that the fruit at 2 C most likely was still ripening and softening, but at a slower rate. This continuation in ripening occurred because chill injury symptoms do not prevent the continuation of ripening (Lurie and Sabehat 1997). There were only minimal differences in juiciness between treatments and there was no clear trend in juiciness during storage. Mealiness scores stayed relatively the same over time, but at Day 6, the fruit held at 2 C were less mealy in comparison to the whole fruit controls at 12 C. There were no significant differences in overall flavor intensity at each evaluation day, but overall flavor intensity tended to decrease over time. Overall ripe tomato flavor of whole fruit controls stored at 12 C increased on Day 6 .Off flavors did not differ between treatments during storage, but over time, all samples displayed an increase in off flavors. Acidity decreased in sliced fruit at Day 3, and the acidity of the controls did not differ much due to treatment at any storage period, but they did decrease over time for all treatments. Sweetness remained constant throughout the study. Sweetness and acidity did not seem to be important factors in assessing the shelf life of sliced and stored tomatoes.

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34 The overall acceptability of the 2 C whole controls and the 2 C stored sliced fruit was significantly lower than the whole fruit held at 12 C around Day 6. Whole fruit stored at 12 C had better quality than other treatments because at 12 C, fruit still ripen and develop flavors (Lurie and Sabehat 1997), thereby improving quality. Symptoms of chilling injury generally occur after the fruit has been held in low temperatures for a period of a 7 days or more, and then transferred to approximately 20 C (Lurie and Sabehat 1997). There is a relationship between the time and temperature of exposure of the plant to chill injury conditions in order for development of chill injury symptoms(Wang 1990). After a critical number of hours have passed, the effects of chilling on the commodity contribute less to the overall severity of the injury (Wang 1990). In this study with light-red tomatoes, the data from Table 1 indicates that the critical time for development of chill injury symptoms (off-odors, less firmness, and overall decay of the fruit) is around between 3 and 6 days. Sliced fruit also seemed to experience chilling injury. Water-soaked areas occur when the fruit has been sliced and stored. It generally occurs when fruit placed in chilling injury temperatures (colder than 13 C) and has not been placed back at room temperature. (Hong and Gross, 2001). Hong and Gross (2001) used water-soaked appearance as an indicator of chilling injury. In a fresh-cut tomato study, visual quality, aroma, and texture all decreased over time after 10 days at 5 C (Artes et al. 1999), which concurred with sensory results in Table 1. These results also indicate that sliced tomatoes are perhaps chill injured and have a short shelf life of approximately 6 days.

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35Table 4-1: The effects of treatment at each storage time on sensory attributes of sliced and whole light-red-stage “Mountain Sp ring” tomatoes stored at 2C and 12 C Time (d) Treatment1 Red Color Intensity Fresh Tomato Aroma Offodors Firmness Juiciness Mealiness Overall Flavor Intensity Overall Ripe Tomato Flavor Off-flavorsAcidity Sweetness Overall Acceptability 2W 7.1a2 8.6a 2.4ab 9.5a 8.7a 6.4a 9.4a 7.8a 1.8a 9.4a 4.9a 7.9a 0 12W 6.6a 8.4a 2.3b 9.8a 8.5a 5.7a 8.8a 7.9a 2.0a 9.4a 5.0a 8.0a 2SLI 6.8a 7.2a 3.6a 8.3a 8.1a 6.6a 9.4a 7.8a 2.5a 9.5a 5.1a 7.9a 2W 9.1a 8.9a 3.7a 9.4a 6.4ab 4.6a 8.2a 6.8b 2.8b 7.4ab 3.8a 7.3a 12W 7.1a 8.7a 1.9a 8.9a 7.3a 5.9a 8.3a 7.9a 1.4b 8.8a 4.9a 7.8a 3 2SLI 7.7a 8.2a 3.4a 6.0b 5.6b 5.8a 7.9a 6.9b 5.1a 6.4b 5.3a 5.4a 2W 6.7b 7.5a 4.9a 8.6a 8.3a 5.7b 8.4a 7.0b 3.6a 7.0a 5.3a 6.9b 12W 9.8a 8.6a 3.3a 8.3ab 7.4a 6.5a 8.3a 8.8a 2.6a 6.3a 5.9a 8.4a 2SLI 7.8b 8.2a 3.9a 6.7b 7.2a 5.7b 7.8a 7.0b 3.0a 5.7a 5.8a 6.9b 6 Time Effect ns * ns ns * ns 1Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3* indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect

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36 Other quality attributes There was no significant change in percent soluble solids for all treatments during storage, as shown in Table 2. This is in agreement with sensory results for sweetness during storage as shown in Table 1. Sensory results indicated there was no significant change in sweetness for all treatments over time. Sliced fruit maintained pH over time as shown in Table 2. As indicated in Table 1, there was a decline in sensory acidity of samples over time and an increase in off-flavors. Titratable acidity decreased slightly for both whole and sliced tomatoes at 2C over time. This concurs with results from Artes et al. (1998), in that sliced tomatoes held at 2 C had decreases in titratable acidity. Table 2 indicates that sliced fruit experienced a significant decrease in firmness from an initial 1.47 N to 0.8 N by Day 3, and remained soft for the remainder of storage. In comparison to the sliced fruit, whole fruit controls had a moderate decline in firmness over time. Initially, their firmness was approximately 1.4 N, and by Day 3 they had decreased to 1.0 N. After 3 days, their firmness continued to decrease, and the whole fruit were as soft as the sliced fruit. This seems to indicate that that the whole controls stored at 2 C were beginning to display symptoms of chill injury, and the controls stored at 12 C were beginning to become over ripe. Compression measurements of sliced and stored light-red tomatoes concurred with Watada and Qi (1999) in that there is a definite loss of firmness in sliced fruits over time but there was still a great deal of variability regarding firmness of slices. As noted in a fresh-cut study by Artes et al. (1999), variability arises due to location of the slice relative to the ends of the fruit.

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37 Although slices were chosen from the middle of the fruit, there was still a great deal of variability in firmness. Parts of the slices that were in contact with the Fridgesmart package were less firm. Also, the degree of water-soaked appearance in different areas of the flesh cause great amounts of variability in the firmness of the slice. Instron measurements showed that whole fruit controls held at 12 C were the least firm. This does not agree with the sensory firmness results as indicated in Table 1, where sliced fruit have the lowest firmness during storage. Wu and Abbott (2002) conducted a study where they surveyed many different methods of firmness measurements of sliced tomatoes. Possibly a different method, such as using force relaxation on the slices, where the impact of viscoelastic changes is taken into consideration (Wu and Abbott, 2002) would have been more effective. In general, there was greater variability within treatments than between treatments. The L value, or degree of lightness, decreased in the sliced fruit over time, as shown in Table 2. The fruit that were kept at chill injury temperature (2 C) maintained their L value. The “a” value has been used as an indicator of red color development (Artes et al. 1999). Tomatoes stored at 2 C also had increased “a” values, indicating a slight increase in red color over time, and they maintained their hue value throughout storage. Sliced fruit maintained its red color and hue throughout storage. Hue refers to the characteristic of a color that distinguishes red from yellow from blue (Color Cube, 2000). This agrees with sensory data as shown in Table 1.Sliced fruit and whole fruit held at 2 C had less red color intensity than whole fruit held at 12 C. In light-red tomato fruit (fruit with outside hue angle’s between 65 and 75), it has been found that juice color measurement maintained for sliced tomatoes held at 2 C (Artes and other, 1999).

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38 Table 4-2:The effects of treatment on quality attributes of sliced and whole light-redstage “Florida 47” tomatoes stored at 2C and 12C Treatment1 Time (d) % soluble solids pH g citric acid/100m L Compression Force (N) L a Hue (tan-1 (b/a)) 12W 0 4.5a2 4.4a 0.40a 1.47a 43.2a 9.9a 52.5 2W 0 4.6a 4.4a 0.40a 1.5a 43.1a 10.3a 53.6a 2SLI 0 4.7a 4.4a 0.40a 1.38a 41.1a 11.7a 50.3a 12W 3 4.5a 4.4a 0.40a 1.01a 38.3ab 12.4a 47.5a 2W 3 4.6a 4.4a 0.36b 1.01a 41.1a 10.3ab 50.7a 2SLI 3 4.7a 4.4a 0.35b 0.80b 34.9b 9.7b 51.6a 12W 6 4.6a 4.3a 0.40a 0.67b 39.5b 14.1a 42.8b 2W 6 4.6a 4.3a 0.31b 0.75b 46.2a 11.0b 50.8a 2SLI 6 4.6a 4.3a 0.31b 0.96a 40.1b 10.9b 47.4ab Time Effect ns3 ns * * 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect Red-stage Tomatoes: Replication 1 Sensory results As for the light-red-stage, red-stage “Florida 47” tomatoes were either sliced and held at 2 C or kept whole at either 12 or 2 C for a storage period of 6 days. After the designated storage period, whole tomatoes were sliced and all treatments were evaluated. As indicated by Table 3, many attributes for red-stage tomatoes experienced changes over time, as well as differences compared to other treatments. In red-stage tomatoes, most changes were noticeable by Day 3. This is three days earlier than in light-red-stage tomatoes, as shown in Table 1.

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39 Red color intensity had variable results over time for red-stage “Florida 47” tomatoes. At Day 6, whole fruit controls held at 2 C had less red color intensity than the other two, indicating possible chilling injury. Fresh tomato aroma did not differ due to treatment during storage, but decreased over time for all treatments. Off odors were higher in sliced fruit by Day 3 and whole fruit controls stored at 12 C had less off odors than sliced fruit and whole fruit held at 2 C by Day 6. The whole fruit stored at the holding temperature of 12 C, had development of off-odors. Sliced fruit held at 2C were less firm than whole fruit controls by Day 3 of storage. This indicates that the whole fruit controls held at 12 C might have become over ripe, while senescence in the sliced fruit led to deterioration of the pericarp. Juiciness did not differ due to for most treatments over time, but decreased in sliced fruit at Day 3 of storage. There was also a loss of juiciness for all samples throughout time. Whole fruit controls were either chill injured (2 C), or overripe (12 C), causing a loss in cell turgor and resulting in less juiciness. At Day 3, whole fruit controls at 2 C were mealier than other treatments, but at Day 6, all fruit had the same level of mealiness, indicating that there is no general trend in the production of mealiness. The overall flavor intensity and ripe tomato flavor of slices declined at Day 3. At Day 6, the whole fruit held at 12 C displayed less overall flavor intensity than the fruit held at chilling temperatures. This is most likely due to the fruit becoming over-ripe. All treatments had less ripe tomato flavor by Day 6 of storage. Sliced fruit held at 2 C had increased levels of off flavors on Day 3, while whole fruit held at 2C had more off flavors by Day 6. All treatments generally maintained

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40 acidity over time. Samples held at 2 C decreased in sweetness over time beginning around Day 3, but by Day 6, all samples had lower sweetness than initial levels. Sliced fruit displayed lower overall acceptability in comparison to whole controls at Day 3, but at Day 6, all fruit were less acceptable than initially. Other quality attributes Other quality attributes As indicated in Table 4, all treatments maintained their soluble solids at approximately 4.6 B. This agrees with findings from Gil et al. (2002). Sliced tomatoes stored in MAP maintained soluble solids regardless of temperature of storage and permeability of film. Panelists found a loss in sweetness and an increase in off-flavors for all treatments during storage, as indicated in Table 3. Possibly the increase in off-flavors resulted in a loss of sweetness perception. Whole fruit controls and sliced fruit held at 2 C maintained pH over storage as shown in Table 4. As indicated by Table 3, panelists detected a slight decrease in acidity. Titratable acidity also decreased for sliced for sliced tomatoes stored at 2 C. This agrees with findings from Gil et al. (2002); who found a decrease in pH and titratable acidity in sliced fruit. All treatments of fruit were not firm, having compression force of 0.7 N. This texture did not change much over time and did not result in significances between treatments, as shown in Table 4. Gil et al. (1999) concluded that a loss of firmness of fresh-cut tomato slices was probably linked to ripeness stage of whole fruit. As in the light-red-stage, this did not concur with the sensory results as shown in Table 3. Sliced fruit and whole fruit controls stored at 12 C were less firm than whole fruit controls held at 2 C. This indicates that perhaps sensory results are more sensitive than mechanical

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41Table 4-3:The effects of treatment at each storage time on sensory attributes of sliced and whole red-stage “Florida 47” tomato es stored at 2C and 12C Time (d) Treatment1 Red Color Intensity Fresh Tomato Aroma Offodors FirmnessJuicinessMealiness Overall Flavor Intensity Overall Ripe Tomato Flavor Offflavors Acidity Sweetness Overall Acceptability 2W 11.9a2 10.2a 3.9a 9.0a 9.1a 6.3a 9.2a 10.1a 2.0a 7.5a 6.1a 9.7a 0 12W 11.6a 10.4a 3.3a 8.0a 9.2a 6.6a 9.1a 9.9a 1.9a 7.4a 6.0a 8.8a 2SLI 12.0a 10.2a 3.5a 7.8a 9.5a 6.7a 9.2a 10.0a 2.2a 7.5a 7.1a 9.7a 2W 9.7a 9.2a 2.5b 8.4a 7.9a 7.0ab 9.2a 9.0a 3.0b 8.0a 5.5ab 8.4a 3 12W 10.0a 9.1a 2.7b 8.5a 8.2a 6.9b 9.2a 9.6a 2.0b 7.7a 6.6a 8.8a 2SLI 8.9b 8.1a 5.2a 5.8b 6.0b 8.5a 6.6b 7.5b 5.1a 6.6a 5.1b 5.4b 2W 10.5b 9.1a 4.4a 10.2a 8.2a 5.7a 9.4a 8.8a 4.2a 7.0a 4.0a 7.4a 6 12W 11.8a 9.9a 2.5b 7.9b 7.6a 6.5a 7.5b 7.8a 3.0b 5.7a 4.0a 7.2a 2SLI 11.4a 8.6a 4.4a 6.3c 7.8a 6.5a 9.4a 8.6a 3.3ab 5.8a 4.7a 6.5a Time Effect3 * * ns * * * 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect

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42 Instron compression results, or the Instron measurements were inadequate for detecting firmness changes in sliced tomatoes. Over time, all fruit generally maintained their "a" value, indicating no further red color development of red-stage tomatoes, as shown in Table 4. Sliced fruit experienced a decrease in L value over time. This occurred when there was an increase in water-soaked appearance of slices. Table 4-4:The effects of treatment on quality attributes of sliced and whole red-stage “Florida 47” tomatoes stored at 2C and 12C Treatment1 Time (d) % soluble solids pH g citric acid/100mL Compression Force (N) L a Hue (tan-1 (b/a)) 12W 0 4.6a 4.4a 0.35a 0.72a 42.6a 16.3a 41.9a 2W 0 4.6a 4.4a 0.35a 0.70a 41.5a 14.7a 41.5a 2SLI 0 4.6a 4.4a 0.35a 0.69a 39.0a 16.7a 40.8a 12W 3 4.6a 4.4a 0.36a 0.73a 40.8a 15.2a 39.8a 2W 3 4.5b 4.4a 0.36b 0.64a 42.9a 15.2a 40.3a 2SLI 3 4.5b 4.4a 0.34b 0.61a 35.9b 15.2a 37.7a 12W 6 4.6a 4.4a 0.36a 0.48a 38.2b 16.1a 40.9a 2W 6 4.6a 4.4a 0.35a 0.55a 42.4a 16.1a 41.2a 2SLI 6 4.6a 4.4a 0.33b 0.46a 32.6c 14.2a 34.0b Time Effect3 ns ns * * 1Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2Means within a storage time followed by the same letter are not significantly different (Duncan’s Multiple Range Test, 0.05) 3 indicates a significant storage effect at the 0.05 level. “ns” indicates a non significant storage time effect. Light-red-stage Tomatoes: Replication 2 Sensory results In replication 2, light-red ““Florida 47”” tomatoes (average hue=55) experienced similar sensory responses during storage as the first replication, as indicated in Table 5. The time of storage was increased from 6 to 9 days. At 6 days, sliced fruit were still

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43 relatively acceptable to panelists. It was thought that a longer storage period might result in greater differences in attributes between treatments. Beginning at Day 3, there was a trend for less red color intensity for whole fruit controls and sliced fruit stored at 2 C. Water-soaked appearance remained relatively constant throughout time for whole fruit controls, but sliced samples increased in their watersoaking over time. All treatments maintained their fresh tomato aroma over time and there were no differences between treatments at each storage period. Over time, off-odors generally increased throughout storage. Samples decreased in firmness over time. Sliced fruit held at 2 C decreased in juiciness during storage comparatively to the whole controls at 2 C and 12 C, showing characteristic signs of desiccation that occur to sliced fruit. There were no differences between treatments at respective storage times for mealiness, but all samples increased in mealiness throughout storage. Overall flavor intensity of all samples did not change throughout the study the study. Overall ripe tomato flavor, however, increased over time for all samples. There were no differences between treatments for off flavors, but all samples showed increased off flavors over time. Acidity decreased over time for all samples. Sweetness increased at Day 6 for all samples and fruit held at chilling temperature were rated as the highest in sweetness. All samples decreased in acceptability over time.

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44Table 4-5: The effects of treatment at each storage time on sensory attributes of sliced and whole light-red-stage “Florida 47” tomatoes stored at 2C and 12C Time (d) Treatment1 Red Color Intensity Watersoaked Appearance Fresh Tomato Aroma Offodors Firmness Juiciness Mealiness Overall Flavor Intensity Overall Ripe Tomato Flavor Offflavors Acidity Sweetness Overall Acceptability 2W 7.6a2 2.3a 9.0a 1.6a 9.3a 8.8a 3.6a 8.1a 8.3a 1.8a 7.6a 5.9a 8.6a 0 12W 8.0a 2.1a 9.3a 1.4a 8.3a 9.0a 3.1a 9.1a 8.8a 2.3a 7.0a 5.8a 8.2a 2SLI 8.2a 1.9a 9.1a 1.8a 8.9a 9.1a 3.4a 8.8a 8.2a 2.6a 7.1a 5.6a 8.0a 2W 6.6b 3.2b 9.0a 3.0ab 10.3a 7.7b 3.1a 8.4a 9.3a 1.5a 5.7a 5.3a 7.7a 3 12W 10.5a 2.9b 9.3a 1.4b 11.7a 6.2c 2.0b 9.9a 9.8a 1.5a 6.5a 5.0a 8.2a 2SLI 8.0b 6.5a 8.4a 3.3a 8.0b 9.5a 3.0ab 8.4a 8.7a 1.9a 6.5a 4.4a 7.8a 2W 8.6b 2.4a 8.0b 3.9a 10.0a 8.3a 3.3a 9.7a 8.4ab 3.5a 9.1a 4.1a 7.6a 6 12W 11.0a 2.0a 10.2a 2.2a 8.6a 8.8a 3.2a 9.6a 9.7a 2.8a 8.1a 4.0a 8.0a 2SLI 7.5b 2.3a 9.2a 3.6a 9.3a 8.0a 3.7a 9.6a 8.2b 4.3a 8.5a 3.1a 5.7b 2W 5.3b 2.8a 11.1a 2.6a 8.7a 8.7a 5.1a 9.9a 10.4a 1.6a 5.7a 10.2a 7.3a 9 12W 9.7a 3.3a 9.8a 3.4a 8.4a 8.5a 3.4a 10.0a 11.3a 2.8a 4.8a 8.5ab 7.1a 2SLI 6.6b 4.2a 9.4a 4.6a 7.3a 6.9b 6.4a 8.5a 9.3a 2.8a 3.8a 7.5b 7.3a Time effect3 * ns * ns ns ns * 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect

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45 Other quality attributes Sliced fruit and whole fruit controls at 2 C maintained their soluble solids, as indicated in Table 6. Sensory results also indicated that there was no significant change in firmness for all treatments throughout storage, as indicated in Table 5.The pH of treatments generally followed the same trends as in replication 1; all fruit basically maintained pH, as shown in Table 6. Panelists did not indicate a change in acidity for all treatments throughout storage, as indicated in Table 6, but there was a slight loss in titratable acidity for sliced fruit and whole fruit held at 2 C. As in replication 1, sliced fruit exhibited an earlier decrease in firmness over time. Around three days of storage, their firmness decreased from 1.4 N to 0.8 N, as shown in Table 6. The whole fruit controls held at 2 C and 12 C maintained their firmness over storage. Both whole controls displayed an increase in a value, indicating an increase in red color development. L values were maintained over time, indicating that the degree of water-soaked appearance was less in comparison to red-stage fruit at Day 6. All treatments maintained their hue value throughout storage, indicating there was no major change in color development throughout storage, as indicated in Table 6. Red-stage Tomatoes: Replication 2 Sensory results In replication 2, red “Florida 47” tomatoes (average hue= 44) had similar sensory results as replication 1, as shown in Table 7. Sliced fruit and whole fruit controls held at 12 C maintained their red color intensity over time, while whole fruit controls held at 2 C lost their red color intensity. All fruit increased in watersoaking during storage, and

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46 red-stage fruit had a greater degree of water-soaked appearance than light-red-stage fruit. Sliced fruit exhibited the most watersoaking throughout storage. Whole fruit controls maintained their fresh tomato aroma, while sliced fruit had a decline in fresh tomato Table 4-6:The effects of treatment on quality attributes of sliced and whole light-redstage “Florida 47” tomatoes stored at 2C and 12C 1Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2Means within a storage time followed by the same letter are not significantly different (Duncan’s Multiple Range Test, 0.05) 3 indicates a significant storage effect at the 0.05 level. “ns” indicates a non significant storage time effect. aroma over time. Sliced fruit also had an increase in off odors relative to the whole controls over time. Firmness was maintained throughout storage for all treatments. Juiciness decreased for all treatments over time, showing no differences between treatments. Mealiness increased in sliced samples and maintained relatively high for whole controls. Treatment1 Time (d) % soluble solids pH g citric acid/100m L Compression Force (N) L a Hue (tan-1 (b/a)) 12W 0 4.5a2 4.3a 0.40a 1.48a 47.6a 16.0a 43.6a 2W 0 4.5a 4.3a .40a 1.43a 45.6a 14.0a 47.5a 2SLI 0 4.5a 4.3a .40a 1.41a 47.4a 14.3a 48.7a 12W 3 4.5a 4.3a .39a 1.14a 45.8a 18.0a 39.2b 2W 3 4.5a 4.3a .36b 1.26a 46.6a 14.5c 45.1a 2SLI 3 4.6a 4.3a .35b 0.83b 46.1a 16.2b 42.4a 12W 6 4.7a 4.3a .39a 1.30a 43.9b 21.1a 40.1a 2W 6 4.6a 4.3a .31b 1.29a 46.1ab 17.6b 42.1a 2SLI 6 4.5b 4.3a .31b 0.89b 47.5a 13.8c 43.8a 12W 9 4.7 4.3a .37a 1.16a 44.9b 18.4a 41.3b 2W 9 4.6 4.3a .36a 0.96ab 48.7a 16.3ab 43.9a 2SLI 9 4.5 4.3a .32a 0.88b 44.8b 14.8b 49.1b Time effect3 ns ns * * ns

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47 Overall flavor intensity decreased in sliced samples and maintained in whole fruit controls. Overall ripe tomato flavor decreased in whole fruit controls at 2 C and sliced fruit; ripe tomato flavor slightly increased for whole fruit at 12 C during storage. Off flavors were higher in sliced fruit than whole fruit controls and increased over time. Acidity was maintained in whole fruit controls at 12 C, and decreased in sliced fruit and whole fruit controls at 2 C. There was a loss in sweetness in sliced samples over time as well as compared to the other treatments. Sliced fruit had less acceptability than whole fruit controls at Day 3 and were not acceptable at Day 6 of storage. Other quality attributes All treatments maintained their soluble solids over time (Table 8). According to the sensory results in Table 7, sliced samples were less sweet compared to the other two treatments. This also agreed with replication 1. The increase in off-flavors, might again have caused decrease in the perception of sweetness. Table 8 indicates that all treatments maintained their pH over time, as in replication 1, but had a slight decrease in titratable acidity. This agrees with sensory results shown in Table 7. Panelists noted a loss in acidity at Day 6 for sliced tomatoes held at 2 C. As in replication 1, Instron compression measurements demonstrated that all treatments maintained their firmness throughout storage (Table 8). These results agreed with sensory results as indicated in Table 7. Results also support the idea that the loss of firmness of fresh-cut tomatoes slices is probably linked to ripening stage of whole fruit (Gil, 1999). Sliced fruit decreased in L value compared to whole fruit controls stored at 2 C and 12 C, as shown in Table 8. Water-soaked appearance, as in replication 1, likely caused the decrease in L value of sliced tomatoes stored at 2 C.

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48Table 4-7:The effects of treatment at each storage time on sensory attributes of sliced and whole red-stage “Florida 47” tomato es stored at 2C and 12C. Time (d) Treatment1 Red Color Intensity Watersoaked Appearance Fresh Tomato Aroma Offodors Firmness Juiciness Mealiness Overall Flavor Intensity Overall Ripe Tomato Flavor Offflavors Acidity Sweetness Overall Acceptability 2W 9.5a2 3.4a 9.7a 2.5a 9.3a 9.1a 3.9a 8.7a 9.1a 3.2a 6.4a 5.6b 7.8a 0 12W 9.6a 4.0a 10.5a 2.9a 8.9a 9.0a 4.1a 8.4a 8.9a 2.9a 6.1a 6.3ab 8.0a 2SLI 9.7a 3.7a 10.5a 2.7a 9.6a 8.9a 3.6a 9.2a 8.8a 2.9a 7.2a 6.9a 7.1a 2W 8.6b 3.3a 10.0a 2.2b 9.5a 8.7a 3.9b 9.0a 9.1a 2.6ab 7.2a 6.0ab 8.4a 3 12W 9.3b 3.1a 9.8a 2.9ab 10.0a 8.8a 3.4b 9.2a 9.3a 2.0b 6.9a 6.1a 8.4a 2SLI 10.5a 4.5a 8.0b 4.1a 13.7a 8.7a 5.1a 7.7b 7.5b 3.4a 6.6a 4.7b 6.4b 2W 6.9a 4.5ab 9.1ab 4.6b 8.6a 7.3a 3.8a 8.0a 7.7a 3.5b 4.4a 5.4a 6.8a 6 12W 8.3a 3.6b 9.8a 2.8b 10.1a 7.7a 3.5a 7.3a 10.7a 3.3b 6.0a 4.3ab 6.4ab 2SLI 8.3a 5.2a 6.6b 8.7a 8.5a 6.6a 4.2a 7.9a 7.4a 6.9a 4.7a 2.9b 3.7b Time effect3 * * * ns * * * 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect

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49 Light-red-stage Tomatoes: Replication 3 Sensory results Light-red “Mountain Spring” sliced tomatoes (average hue= 50) experienced a loss in quality compared to whole fruit controls. “Mountain Spring” Tomatoes were substituted for “Florida 47” tomatoes because of their availability at the time of this study. As shown in Table 9, there was a loss of red color intensity over time for sliced and whole tomatoes held at 2 C. Sliced fruit exhibited an increased in water-soaked Table 4-8:The effects of treatment on other quality attributes of sliced and whole redstage “Florida 47” tomatoes stored at 2C and 12C Time Treatment1 (d) % soluble solids pH g citric acid/100 mL Compression Force (N) L *a Hue (tan-1 (b/a)) 12W 0 4.6a2 4.4a .35a 0.99a 43.8a 17.6a 44.5a 2W 0 4.6a 4.4a .35a 0.96a 43.3a 18.2a 43.8a 2SLI 0 4.6a 4.4a .35a 0.83a 44.6a 20.7a 38.5a 12W 3 4.7a 4.4a .35a 0.93a 45.0a 19.6a 45.0a 2W 3 4.6b 4.4a .35a 0.99a 45.3a 20.3a 45.3a 2SLI 3 4.6b 4.4a .34a 0.78a 44.4a 18.1b 44.4a 12W 6 4.7a 4.4a .35a 0.84b 45.4a 19.9a 43.2a 2W 6 4.6b 4.4a .35a 0.99a 45.7a 18.9ab 41.5a 2SLI 6 4.6b 4.4a .31b 0.80b 42.4b 17.9b 39.4a Time effect3 ns ns * * ns 1Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2Means within a storage time followed by the same letter are not significantly different (Duncan’s Multiple Range Test, 0.05) 3 indicates a significant storage effect at the 0.05 level. “ns” indicates a non significant storage time effect. appearance over time and were more translucent with respect to whole fruit controls. Whole fruit controls held at 2 C, as well as sliced fruit, had decreased in fresh tomato

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50 aroma over time and were less fresh than whole fruit controls held at 12 C. The reverse held true for offodors. Whole fruit controls at 12 C were firmer than treatments held at 2 C. Juiciness was maintained over time for all treatments. Treatments held at 2 C experienced increased mealiness compared to controls at 12 C. The overall flavor intensity and overall ripe tomato flavor of controls held at 12 C was maintained over time, while treatments held at 2 C had decreased levels of overall flavor intensity. Off flavors increased over time for sliced fruit compared to whole fruit controls. Acidity was maintained in whole fruit at 12 C, but decreased in treatments held at 2 C. Sweetness was maintained over time. Sliced fruit and whole fruit stored at 2 C had lower acceptability than whole fruit at 12 C. Other quality attributes Soluble solids results for replication 3 were similar to results in replication 2. All fruit maintained soluble solids (Table 10). Sensory results in Tables 9 and 10 concurred with percent soluble solids results in that there was no difference in sweetness between treatments. All treatments basically maintained their pH over time, as indicated in Table 10. There was a decrease in titratable acidity of sliced fruit, which agrees with replications 1 and 2, but sensory results did not indicate a change in acidity over time. These fruit were initially softer compared to the “Florida 47” variety. Whole fruit controls maintained firmness, while sliced samples decreased in firmness throughout storage as indicated in Table 10. This agrees with sensory results shown in Tables 9.

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51 For surface color of the slices, sliced fruit held at 2 C had the least amount of red color intensity over time, as indicated by Table 10. The a value changed from 16.1 to 13.5. Also, the hue, decreased over time. The hue of the sliced fruit changed from approximately 3640.4. Controls stored at 2 C maintained their red color intensity over time. There a value was approximately 16.1 throughout storage, but their hue increased from 39.145.1, showing a loss of red color intensity, characteristic of chill injury. Microbiological results Sliced tomatoes experienced increases in both aerobic and yeast and mold plate counts. Aerobic Colony Forming Units(CFU/g) increased over time from 10x101cfu/g to 10x106 cfu/g by Day 10.Yeast and mold pate counts increased from 10x101 cfu/g to 10x103 cfu/g by Day 7. For most products, the level of microbes that constitutes spoilage is approximately 1 x 107 microbes per gram of sample(Davis and Connor, 2001), usually producing a visible color change of the product, or odors from the byproducts of the microbes (Davis and Connor, 2001).The results indicate that the tomato slices were still considered edible, but were on the verge of being spoiled. Red-stage Tomatoes: Replication 3 Sensory results Sensory results for replication 3 were similar to replications 1 and 2, as indicated by Table 11. There was no development of red color intensity throughout storage for redstage “Mountain Spring” tomatoes (average hue=40). Sliced fruit showed signs of increased watersoaking over time and compared to controls, as indicated by replications 1 and 2. Controls held at 12 C held less fresh tomato aroma and decreased over time. There were no differences between treatments during storage for off odors, but all sample

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52Table 4-9:The effects of treatment at each storage time on sensory attributes of sliced and whole light-red-stage “Mountain Spr ing” tomatoes stored at 2C and 12C. Time (d) Treatment1 Red Color Intensity Watersoaked Appearance Fresh Tomato Aroma Offodors Firmness Juiciness Mealiness Overall Flavor Intensity Overall Ripe Tomato Flavor Offflavors Acidity Sweetness Overall Acceptability 2W 9.8a2 4.3a 9.9a 2.2a 7.2a 8.6b 5.4a 8.3a 9.0a 2.6a 7.3a 6.0a 8.5a 0 12W 9.6a 4.2a 10.7a 2.1a 7.0a 10.4a 4.5a 8.5a 9.3a 2.1a 6.4a 6.3a 9.0a 2SLI 9.2a 3.9a 9.5a 2.4a 7.7a 9.4a 5.2a 8.7a 8.0a 2.9a 7.0a 5.6a 7.4a 8.9a 2W 9.6a 2.9 b 9.7 a 2.5a 8.0a 8.7a 4.5ab 10.1a 2.4a 7.0a 6.6a 8.2b 3 12W 9.7 a 3.4ab 10.0 a 2.8a 8.3a 9.3a 3.8b 9.6a 10.3a 1.8a 8.1a 6.3a 9.7a 2SLI 9.8 a 4.5 a 9.0 a 2.9a 7.0a 9.1a 5.8a 8.3a 9.1a 2.6a 7.0a 6.1a 7.8b 7.5b 2W 7.0b 4.1a 9.5a 2.5ab 7.7ab 8.8a 5.5a 7.6b 2.4a 6.0a 6.0a 6.0b 6 12W 8.6a 4.0a 10.4a 1.7b 7.1b 9.6a 6.0a 8.6ab 9.6a 2.1a 7.1a 5.7a 8.4a 2SLI 8.6a 3.9a 9.2a 3.0a 8.3a 9.2a 3.7b 9.6a 8.6ab 2.4a 6.7a 5.9a 7.8a 7.1b 2W 6.6c 4.6ab 8.1b 4.1a 5.8b 8.1a 8.7a 7.1b 3.7ab 6.4b 6.0a 6.1b 10 12W 9.5a 3.9b 9.4a 3.0b 6.0b 8.9a 4.5c 9.4a 9.8a 2.8b 8.8a 5.7a 9.0a 2SLI 8.0b 5.7a 7.9b 4.3a 8.7a 9.0a 7.3b 7.1b 7.2b 4.8a 6.6b 5.4a 6.0b Time Effect3 * * ns * * ns 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect

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53 Table 4-10:The effects of treatment on other quality attributes of sliced and whole redstage “Florida 47” tomatoes stored at 2C and 12C Time Treatment1 (d) % soluble solids pH g citric acid/100 mL Compression Force (N) L *a Hue (tan-1 (b/a)) 12W 0 4.5a2 4.3a 0.35a 0.61a 43.6a 16.1a 37.0a 2W 0 4.5a 4.3a 0.35a 0.81a 45.9a 16.2a 39.4a 2SLI 0 4.5a 4.3a 0.35a 0.70a 45.9a 16.1a 36.1a 12W 3 4.6a 4.3a 0.35a 0.53a 44.5a 17.8a 39.8a 2W 3 4.5b 4.3a 0.35a 0.59a 45.6a 16.6b 38.2ab 2SLI 3 4.5b 4.3a 0.35a 0.59a 40.9b 17.6a 36.3b 12W 6 4.6a 4.4a 0.35b 0.37a 46.2a 17.9a 39.3b 2W 6 4.5b 4.3b 0.36ab 0.67a 47.2a 16.2b 45.5a 2SLI 6 4.5b 4.3b 0.4a 0.61a 44.9b 14.0b 42.1ab 12W 10 4.6a 4.4a 0.37a 0.55a 42.9ab 18.5a 40.4b 2W 10 4.6a 4.3b 0.36a 0.45b 45.1a 15.8b 45.1a 2SLI 10 4.5a 4.3b 0.32b 0.35c 39.7b 13.5c 46.8a Time effect3 ns ns * * 1Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2Means within a storage time followed by the same letter are not significantly different (Duncan’s Multiple Range Test, 0.05) 3 indicates a significant storage effect at the 0.05 level. “ns” indicates a non significant storage time effect. showed increased off odors over time. Sliced fruit and fruit at the holding temperature were firmer than fruit held at 2 C. Mealiness remained fairly constant over storage for all treatments. Overall flavor intensity decreased for sliced fruit and fruit held at 12 C. The overall flavor intensity also decreased for fruit at the holding temperature. Off flavors increased over time for all treatments. Sliced fruit, as well as fruit at the holding temperature, had less acidity than fruit held at 2 C. Sweetness was maintained throughout storage. Sliced fruit and fruit at the holding temperature experienced a drop in their acceptability over time and compared with fruit at the holding temperature.

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54 Other quality attributes All treatments maintained their percent soluble solids throughout storage (Table 12). This agrees with sensory data in Tables 11; panelists did not indicate a sweetness change throughout storage. All fruit maintained their pH and percent titratable acidity. Sensory data indicated a loss in acidity of sliced tomatoes throughout storage as in replications 1 and 2. All fruit maintained their firmness over time as indicated by Table 12. Whole fruit controls had a slight increase in firmness over time, indicating possible variability within samples. Some areas of fruit become more bruised than others, causing the sample slice to have many different firmness measurements in its tissue. Sliced fruit had decreased a value throughout storage, most likely resulting from the development of water-soaked appearance, which lessens the intensity of red color. Sensory results did not find a significant change in red color intensity. Microbiological results Sliced tomatoes experienced increases in both aerobic and yeast and mold pate counts. Aerobic Colony forming units increased over time from 10x101 cfu/g to 10x104 cfu/g by Day 7.Yeast and mold plate counts increased from 10x101 cfu/g to 10x103 cfu/g by Day 7. These results indicate that the tomatoes were still considered safe to consume, but most likely were developing off-flavors and odors as a consequence of microbial growth.

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55Table 4-11:The effects of treatment at each storage time on sensory attributes of sliced and whole red-stage “Mountain Spring” tomatoes stored at 2C and 12C. Time (d) Treament1 Red Color Intensity Watersoaked Appearance Fresh Tomato Aroma Offodors Firmness Juiciness Mealiness Overall Flavor Intensity Overall Ripe Tomato Flavor Offflavors Acidity Sweetness Overall Acceptability 2W 10.1a 4.7a 8..9a 3.1a 6.4a 9.6a 5.7a 8.4b 9.8a 3a 5.3a 6.8a 7.6a 0 12W 10.1a 4.6a 9.8a 2.9a 8.2a 9.3a 4.5a 10.2a 10.1a 3a 7.4a 6.9a 9.5a 2SLI 10.6a 5.6a 10.2a 2.3a 7.0a 7.4b 5.8a 8.3b 9.3a 2.2a 6.4a 6.8a 8.1a 2W 10.1a 3.7b 8.8a 2.8a 7.5a 9.9a 6.3a 9.3a 9.6a 2.4a 8.6a 6.7a 8.2a 3 12W 9.9a 4.1b 8.9a 2.7a 6.3b 9.9a 7.3a 8.7a 9.3ab 2.0a 8.3a 6.5a 8.2a 2SLI 10.6a 5.8a 8.5a 2.8a 4.5c 8.9a 8.4a 7.2b 8.3b 2.7a 5.6b 6.5a 6.0b 2W 9.1a 5.3b 8.1a 4.1a 7.3a 9.5a 5.6a 9.0a 8.7a 3.9a 7.4a 5.5a 7.7a 7 12W 9.7a 6.0ab 6.5b 5.0a 5.4b 7.7b 6.9a 6.1c 6.6b 4.4a 6.3ab 4.9a 6.6ab 2SLI 10.0a 7.0a 7.7ab 4.3a 5.7ab 9.2a 5.7a 7.6b 7.7ab 4.1a 6.1b 5.7a 5.8b Time Effect3 ns * * ns * * * 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect

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56 Table 4-12: The effects of treatment on other quality attributes of sliced and whole redstage “Mountain Spring” tomatoes stored at 2C and 12C Hue Treament1 Time (d) Deg. Brix pH g citric acid/100 mL Force (N) L *a (tan-1 (b/a)) 12W 0 4.6a2 4.39a 0.34a .46a 44.0a 19.9a 39.5a 2W 0 4.6a 4.39a 0.34a .49a 44.3a 22.0a 37.9a 2SLI 0 4.6a 4.39a 0.34a .47a 44.2a 20.0a 38.4a 12W 3 4.7a 4.38a 0.34b .88a 42.1ab 21.7a 37.4ab 2W 3 4.6b 4.37a 0.41a .53b 44.6a 19.3b 39.1a 2SLI 3 4.6b 4.38a 0.34b .52b 38.6b 18.1b 36.0b 12W 7 4.7a 4.43a 0.34a .65a 43.3a 19.3a 38.1a 2W 7 4.6b 4.37b 0.34a .49a 42.9a 17.6b 39.6a 2SLI 7 4.6b 4.37b 0.34a .56ab 36.3b 14.8c 36.6b Time effect3 ns ns * * 1Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2Means within a storage time followed by the same letter are not significantly different (Duncan’s Multiple Range Test, 0.05) 3 indicates a significant storage effect at the 0.05 level. “ns” indicates a non significant storage time effect. Study 2 Light-red 1-MCP Treated Sliced Fruit vs. Control Fruit Sensory results Use of 1-MCP has shown to be effective in inhibiting ethylene production, respiration, softening, and color change in fresh-cut apples (Watkins, 2002). On the contrary, 1-MCP treated light-red-stage “Florida 47” tomatoes (MCP) did not experience much change compared to control fruit (CONTROL), regarding most of the attributes and quality parameters as indicated by Tables 13 and 14. MCP treated fruit exhibited less firmness compared to control fruit around Day 7. Also, 1-MCP treated fruit had greater overall flavor intensity compared to control samples by Day 7. Panelists did not detect differences among control fruit and 1MCP treated fruit for the remaining attributes.

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57 In a study where modified atmosphere packaging (MAP) were used with Fresh-cut tomato slices, it was shown that slices held in packages where there were low levels of ethylene had more water-soaked appearance than slices stored in packages of with high ethylene levels (Gil, 2002). Other quality attributes The soluble solids of 1MCP treated light-red “Florida 47” fruit and control fruit maintained their soluble solids over storage, as indicated in Table 14. This data agrees with sensory results in Table 13. Panelists did not detect a significant difference between treatments as well as throughout storage, as shown in Table 13. The pH of both 1-MCP treated fruit and control slices was similar and was maintained throughout time. This concurs with sensory results, which resulted in treatments maintaining their acidity throughout time and not differing from each other The titratable acidity of all fruit maintained at approximately 0.32 percent citric acid, as shown in Table 14. Both treated samples and controls experienced a loss of firmness over time as shown by Table 14. The “a” value decreased over time for both 1-MCP treated fruit as well as control fruit from approximately 11-9, as indicated by Table 16. The hue maintained at approximately 52-55. There was no difference over time or between treatments. Red 1-MCP Treated Sliced Fruit vs. Control Fruit Sensory results Panelists detected differences in water-soaked appearance at Day 7 of storage. Control fruit had less water-soaked appearance than 1-MCP treated fruit. Hong and Gross

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58Table 4-13: The effects of 1-MCP at each storage time on sensory attributes of sliced Light-red “Florida 47” tomatoes. Time (d) Treament1 Red Color Intensity Watersoaked Appearance Fresh Tomato Aroma Offodors Firmness Juiciness Mealiness Overall Flavor Intensity Overall Ripe Tomato Flavor Offflavors Acidity Sweetness Overall Acceptability 0 MCP 8.4a2 4.5a 9.4a 1.9a 7.6a 7.3a 5.2a 7.0a 6.5a 2.1a 4.4a 5.5a 7.3a 0 Control 8.9a 3.7a 8.9a 2.2a 7.3a 7.2a 5.0a 6.6a 6.9a 2.5a 4.8a 5.8a 7.5a 3 MCP 7.5a 6.0a 8.6a 3.0a 6.4a 7.3a 6.1a 6.9a 7.1a 2.6a 5.2a 6.0a 6.7a 3 Control 8.3a 6.0a 8.1a 3.0a 7.1a 7.8a 6.2a 6.8a 6.8a 2.3a 4.9a 5.5a 6.7a 7 MCP 7.6a 4.0a 7.7a 2.9a 8.8a 7.5a 3.8a 8.7a 6.5a 3.0a 6.3a 5.6a 7.0a 7 Control 7.1a 5.4a 7.0a 3.7a 7.0a 7.7a 4.3a 7.5b 5.8a 3.4a 4.9a 5.2a 5.3a Time Effect3 * * ns ns * * * 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect

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59 Table 4-14: The effects of 1-MCP on other quality attributes of sliced light-red-stage “Florida 47” tomatoes stored at 5C Hue Treatment1 Time (d) %Soluble Solids pH %Citric Acid Compression Force (N) L *a (tan-1 (b/a)) MCP 0 4.5a2 4.3a 0.32a 0.97a 43.9a 11.0a 54.0a CONTROL 0 4.5a 4.3a 0.32a 1.2a 44.9a 10.0a 55.3a MCP 3 4.6a 4.3a 0.32a 0.85a 44.3b 13.3a 51.8a CONTROL 3 4.5a 4.3a 0.32a 0.82a 47.3a 12.2a 51.6a MCP 7 4.6a 4.3a 0.31a 0.85a 38.2a 10.1a 52.5a CONTROL 7 4.6a 4.3a 0.32a 0.74a 40.6a 9.3a 56.6a Time effect3 ns ns ns * * 1Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2Means within a storage time followed by the same letter are not significantly different (Duncan’s Multiple Range Test, 0.05) 3 indicates a significant storage effect at the 0.05 level. “ns” indicates a non significant storage time effect. (2001) found that exposing fresh-cut tomatoes to high levels of ethylene reduced watersoaked appearance, they also concluded that unlike whole fruit storage, post harvest storage treatment with fresh-cut tomato should avoid ethylene reduction strategies (Hong and Gross, 2002). Red-stage slices had more water-soaked appearance than light-red-stage samples, which is in agreement with Gil et al. (2002). They also hypothesized that the development of translucence, or water-soaked appearance, was related to the low temperature as well as the stage of development of the fruit. More mature fruit had higher levels of water-soaked appearance (Gil et al. 2002). Other quality attributes The percent soluble solids for light-red-stage “Florida 47” sliced tomatoes treated with 1 ppm 1-MCP and control slices remained consistent throughout storage (Table 16).

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60 There were no treatment differences for soluble solids at any storage as well as between treatments. This concurs with findings from Wills and Ku (2002). The pH and percent titratable acidity were also consistent throughout storage as indicated in Table Treatment effects, as well as storage effects, were negligible and produced no differences between 1-MCP treated slices and control slices. MCP inhibited loss of titratable acidity in comparison with control samples (Wills and Ku 2002), but perhaps longer storage would have supported their findings. There was a general trend in decrease of firmness during storage for both treatments(Table 16). There was no difference between control fruit and 1-MCP treated fruit. This concurred with sensory data, shown in Table 15, in that there were no significant differences between treatments. Over time, both treatments decreased in L value, or lightness of slices. This occurred when the slices were becoming water-soaked. At 7 days, 1-MCP treated slices had lower L values than control samples, as well as lower hue values. This did not concur with sensory data. Although results were not significant for water-soaked appearance, this is probably due to variability within treatment. There are some parts of the tomato, primarily the bottom end, where water-soaked appearance is greater than other part of the fruit (Hong and Gross 2000). Although slices were taken from the middle of the fruit, the slices closer to the bottom end were more water-soaked. Also, within slices themselves, there was variability in the degree of water-soaked appearance. Study 3 Because 1-MCP applied directly to tomato slices was shown to be ineffective in extending shelf life (Study 2), investigating the effects of 1-MCP on whole red-stage tomato fruit, which is sliced after treatment was of interest. Red-stage tomatoes were

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61Table 4-15: The effects of 1-MCP at each storage time on sensory attributes of sliced red-stage “Florida 47” tomatoes. Time (d) Treament1 Red Color Intensity Watersoaked Appearance Fresh Tomato Aroma Offodors Firmness Juiciness Mealiness Overall Flavor Intensity Overall Ripe Tomato Flavor Offflavors Acidity Sweetness Overall Acceptability 0 MCP 11.3a2 4.2a 9.2a 2.7a 5.8a 7.8a 4.2a 7.9a 8.6a 2.15a 4.7a 7.1a 8.0a 0 Control 10.6a 3.4a 8.9a 2.7a 6.0a 8.6a 3.9a 8.1a 8.7a 2.14a 3.8b 6.3a 8.3a 3 MCP 11.4a 3.5a 8.1a 3.0a 7.3a 7.8a 5.2a 8.3a 8.0a 2.6a 4.9a 5.6a 7.3a 3 Control 10.7a 4.0a 7.4a 3.4a 7.0a 6.7a 4.9a 7.7a 7.8a 2.7a 5.1a 6.4a 6.8a 7 MCP 10.1a 7.2a 7.5a 4.8a Z4 Z Z Z Z Z Z Z 7.3a 7 Control 9.2a 6.1b 7.2a 4.6a Z Z Z Z Z Z Z Z 7.0a Time Effect3 * * ns ns ns ns * 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect 4z-samples were unacceptable to taste

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62 Table 4-16: The effects of 1-MCP on other quality attributes of sliced red-stage “Florida 47” tomatoes stored at 5C Hue Treatment1 Time (d) %Soluble Solids pH g citric acid/100mL Compression Force (N) L *a (tan-1 (b/a)) MCP 0 4.6a2 4.4a 0.32a 0.58 a 43.1a 18.0a 43.6a CONTROL 0 4.6a 4.4a 0.32a 0.66 a 42.7a 17.5a 43.3a MCP 3 4.7a 4.4a 0.31a 0.48a 38.3a 15.7a 43.4a CONTROL 3 4.7a 4.4a 0.31a 0.46a 40.2a 16.6a 44.2a MCP 7 4.7a 4.4a 0.32a 0.45a 35.7b 15.1a 44.2b CONTROL 7 4.7a 4.4a 0.31a 0.57a 41.1a 12.7b 49.1a Time effect3 ns ns ns * * 1Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2Means within a storage time followed by the same letter are not significantly different (Duncan’s Multiple Range Test, 0.05) 3 indicates a significant storage effect at the 0.05 level. “ns” indicates a non significant storage time effect. treated at 20C with 1ppm 1-MCP for 24 hours. Tomatoes were then sliced and maintained at 3 C for 6 days. Sensory evaluation of treatment and control samples was conducted at time 0, 2, and 6 days. Throughout storage, all samples had increases watersoaked appearance and off-odors; both treatments had decreases in fresh tomato aroma and overall ripe tomato flavor, as indicated by Table 17. It was found that concentrations of 2 ppm were needed to extend shelf life of ripe tomatoes (Blankenship and Dole 2003). A higher concentration may have been needed for greater effectiveness of 1-MCP treatment. Control fruit had decreases in overall flavor intensity during storage, while 1-MCP treated fruit maintained their overall flavor intensity, which concurred with results from light-red slices in Study 2. Control fruit had less water-soaked appearance than 1-MCP treated fruit on Day 6, but not enough to have significance. Although significance was not obtained, the degree of water-soaked appearance concurs with the findings of Hong and Gross (1999)

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63 The researchers treated slices with an ethylene synthesis inhibitor blocker (AVG) or had ethylene absorbent pads in perforated packages in which the slices were stored. Slices treated with AVG or placed in bags with ethylene absorbent packs had more watersoaked appearance than control samples. So, the trend for an ethylene blocked sample (1MCP treated fruit) to have increases in water-soaked appearance is demonstrated by the sensory results as shown in Table 17. Also, this strengthens the argument that watersoaked appearance is not primarily caused from chilling injury. The expression of watersoaked appearance might be an ethylene dependent phenomenon. Hoeberichts et al. (2002) proved that ethylene perception is needed for the expression of tomato ripening-related genes at the mature green, breaker, and orange (pink) stages. They indicated that ethylene needs to be present throughout the ripening process in order to ripening related physiological responses to occur (Hoeberichts et al. 2002). Hoeberichts et al. (2002) found that they could only delay the ripening of orange tomatoes, which they could completely block the ripening of breaker tomatoes for 18 days. This implies that 1-MCP is more effective on less ripe fruit. The study did not address the effects of 1-MCP on the red ripe stage of development. It has been found that stage of ripeness had significant effects in the application of 1MCP of bananas, pears, and apples (Blankenship and Dole 2003). Commercial lots of bananas yielded mixed lots of fruits when 1-MCP had been applied. Also, the time from harvest to treatment varied the effectiveness of the ethylene inhibitor. For most commodities, treatment needed to be completed early after harvest. Perhaps treatment of less mature whole fruit which is sliced after treatment would be more effective in extending shelf life of fresh-cut tomatoes, but the initial quality of slices would be poor.

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64Table 4-17: The effects of 1-MCP on sensory attributes of whole red “Florida 47” tomatoes, which were sliced and stored at 5C after treatment. Time (d) Treat Red Color Intensity Watersoaked Appearance Fresh Tomato Aroma Offodors Firmness Juiciness MealinessOverall Flavor Intensity Overall Ripe Tomato Flavor Offflavors Acidity Sweetness Overall Acceptability 0 MCP 11.2a2 3.2b 11.5a 1.9a 7.4a 9.9a 5.9a 10.1a 10.6a 1.4a 8.8a 7.6a 9.8a 0 Control 10.8a 4.4a 10.0b 2.8a 7.3a 8.9a 6.4a 9.9a 10.2a 2.2a 8.9a 6.3b 9.1a 2 MCP 11.0a 9.8a 9.8a 2.4a 4.5a 9.6a 7.3a 8.7a 8.2a 3.2a 8.3a 5.8a 7.3a 2 Control 10.7a 9.6a 8.1b 3.4a 4.5a 9.1a 7.3a 8.4a 8.3a 3.0a 6.6b 5.4a 6.7a 6 MCP 10.5a 9.6a 9.0a 3.2a 6.1a 8.9a 7.3a 9.1a 9.4a 2.6a 8.7a 5.6a 7.4a 6 Control 10.3a 7.6a 7.7b 4.7a 7.1a 8.9a 6.4a 8.4a 8.1a 2.1a 7.4a 5.4a 7.7a Time Effect3 ns * * ns ns * * * 1.Treatments: 2W= whole fruit control held at 2C; 12 W= whole fruit control held at 12C; 2SLI= sliced fruit held at 2C 2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05). Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high. 3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect

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65 CHAPTER 5 CONCLUSION The purpose of the first study was to evaluate whether ripeness stage affects the sensory and quality characteristics of sliced and stored tomatoes when compared with whole fruit controls held at chilling and non-chilling temperatures. The most affected attributes to be considered when storing fresh-cut fruit are fresh tomato aroma, watersoaked appearance, firmness and overall flavor intensity. Acidity, sweetness, overall ripe tomato flavor generally were not important in determining the acceptability of sliced and stored tomatoes. Mealiness, juiciness, and water-soaked appearance seemed to be good indicators for chilling injury. The pH, percent titratable acidity, and percent soluble solids overall did not change in the study; they did not have a major impact on the quality of treatments over storage. In all replications, both stages of tomatoes decreased in their fresh tomato aroma, firmness, and overall flavor intensity; they also increased in their water-soaked appearance. These sensory changes also resulted in lowered overall acceptability for the fruit. The study also showed that in many respects, fresh-cut fruits respond to storage similarly as whole tomato fruit held at 2C, and seemed to be chill injured as well as senescing. It was also demonstrated that light-red tomato fruit had a longer shelf life than redstage fruit. In light-red-stage tomatoes, most attributes were maintained throughout storage until around Day 6 of storage. For red-stage tomatoes, changes began sooner, around Day 3 of storage. Although light-red-stage tomatoes maintained their quality over

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66 storage better than red-stage tomatoes, they had lower initial quality. The first study supported the idea that maturity is an important quality factor of fresh-cut fruit. Also, quality and sensory changes that occur to fresh-cut tomatoes during storage are a function of chilling injury as well as senescence. Sliced red and light-red-stage tomatoes were treated with 1-methylecyclopropene for 24 hours at 5C and were stored for 7 days. The sensory and quality results demonstrated that there was not much difference between control slices and slices treated with 1-MCP. Light-red slices treated slices had more water-soaked appearance compared to control fruit, and red treated slices had more water-soaked appearance than control slices. When red-stage whole tomatoes were treated with 1-MCP and then sliced and stored, they had more fresh tomato aroma than control slices. This indicates that 1-MCP might be more effective in delaying ripening in less ripe fruit than red ripe tomato fruit. Overall, the application of 1-MCP on sliced and whole tomato fruit did not extend the quality of fresh-cut tomatoes over storage.

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67 LIST OF REFERENCES Able, A., Wong, L., Prasad, A., and O’Hare, T. 2003. The effects of 1methylcyclopropene on the shelf life of minimally processed leafy Asian vegetables. Postharvest Biology and Technology 27(2): 157-161. Arts, F., Conesa, M., Hernndez, S., and Gil, M.1999. Keeping quality of fresh-cut tomato. Postharvest Biology and Technology 17: 153–162. Auerswald, E., Schwarz D., Kornelson, C., Krumbein, A., and Brckner, B. 1999. Sensory analysis, sugar and acid content of tomato at different EC values of the nutrient solution. Scientia Horticulturae 82(3-4): 227-242. Baritelle, A. and Hyde, G., 2001. Commodity conditioning to reduce impact bruising. Postharvest Biology and Technology 21(3): 331-339. Blankenship, S. and Dole, J. 2003. 1-Methylcyclopropene: a review, Postharvest Biology and Technology 28(1): 1-25. Boukobza, F. and Taylor, A.. 2002. Effect of postharvest treatment on flavour volatiles of tomatoes. Postharvest Biology and Technology 25(3): 321-331. Bramley, P. 2000. Is lycopene beneficial to human health? Phytochemistry 54(3):233-236. Calvin, L. and Cook, R. 2001. US fresh fruit and vegetable marketing: emerging trade practices, trends, and issues. USDA Economic Research Service. Agricultural Economic Report No. 795. http://www.ers.usda.gov. March 2003. Calvin, L., Cook, R., Denbaly, M., Dimitri, C., Glaser, L., Handy, C., Jekanowski, M., Kaufman, P., Krissoff, B., Thompson, G., and Thorsbury, S. 2001. Changing Dynamics in Produce Marketing: Food and Marketing. Economic Research Service. Agricultural Outlook:10-15. Center for Food Safety and Applied Nutrition. 2001. Analysis and Evaluation of Microbiological Safety of Fresh and Fresh-Cut Produce: Economic Impact of Implementing Safety Measures. http://vm.cfsan.fda.gov/list.html. March 2003. Cook, H., Parsons, C., and McColloch, L. 1958. Methods to extend storage of fresh vegetables aboard ships for the US Navy. Food Technology. 12: 548.

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68 Davis, M. and Conner, D. 2001. Module II: 'Louis Pasteur &You'. Theme B Microbiology of Foods Module II.B.1 Microbes of Concern. Gale, W. (web developer) http://www.eng.auburn.edu/~wfgale/usda_course/section2_4.htm. April 2003. DeEll, J., Murr, D., Porteous, M., Vasantha Rupasinghe, H. 2002. Influence of temperature and duration of 1-methylcyclopropene (1-MCP) treatment on apple quality. Postharvest Biology and Technology 24(3): 349-353. Ding, C., Wang, C., Gross, K., and Smith, D. 2001. Reduction of chilling injury and transcript accumulation of heat shock proteins in tomato fruit by methyl jasmonate and methyl salicylate. Plant Science 161(6): 1153-1159. Dong, l., Lurie, S., and Zhou, H. 2002. Effect of 1-methylcyclopropene on ripening of `Canino' apricots and `Royal Zee' plums. Postharvest Biology and Technology 24(2): 135-145. FloridaTomato Committee. 2002. Florida Tomato Facts and Sizing. http://www.floridatomatoes.org/. December 2002. Gil, M. Conesa, M., and Arts, F. 2002. Quality changes in Fresh-cut tomato as affected by modified atmosphere packaging. Postharvest Biology and Technology 25 (2): 199-207. Giovannucci, E. 1999. Tomatoes, tomato-based products, lycopene, and cancer: review of epidemiologic literature. Journal of the National Cancer Institute 91(15): 1331. Hobson, G.. 1987. Low-temperature injury and the storage of ripening tomatoes. Journal of Horticultural Sciences 62: 55–62. Hodges, L. 1997. What is quality… in a tomato? Cooperative Extension, Institute of Agriculture and Natural Resources, University of Nebraska, Lincoln. http://www.ianr.unl.edu/pubs/horticulture/nf353.htm. April 2002. Hoeberichts, F., Van Der Plas, L., and Woltering, E. 2002. Ethylene perception is required for the expression of tomato ripening-related genes and associated physiological changes even at advanced stages of ripening. Postharvest Biology and Technology 26(2): 125-133. Hong, J. and Gross K. 2000. Involvement of ethylene in development of chilling injury in fresh-cut tomato slices during cold storage. Journal of the American Society for Horticultural Science 125:736–741. Hong, J. and Gross, K. 1998. Surface sterilization of whole tomato fruit with sodium hypochorite influences subsequent postharvest behavior of fresh-cut slices. Postharvest Biology and Technology 13: 51–58.

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69 International Fresh-cut Produce Association. 2003. Fresh Cut Facts. Waldinger Creative. http://www.fresh-cuts.org. January 2003. Izumi, H. and Watada, A. 1995. Calcium treatment to maintain quality of zucchini squash slices. Journal of Food Science 60: 789-793. Jiang, W., Sheng, Q., Zhou, X., Zhang, M., Liu, X. 2002. Regulation of detached coriander leaf senescence by 1-methylcyclopropene and ethylene. Postharvest Biology and Technology 26(3): 339-345. Jones, J. 1999. Tomato plant culture: in the field, greenhouse, and home garden. CRC Press. Boca Raton, FL 1-30. Kader, A. and Morris, L. 1975. Amelioration of chilling injury symptoms on tomato fruits. HortScience 10: 324. Ku, V., Wills, R., and Ben-Yehoshua, S. 1999. 1-Methylcyclopropene can differentially affect the postharvest life of strawberries exposed to ethylene. HortScience 34: 119–121. Lorenz, O. and Maynard, D. 1988. Knott’s handbook for vegetable growers (3rd. edition) WileyInterscience, New York. Lurie, S. and Sabehat, A. 1997. Prestorage temperature manipulations to reduce chilling injury in tomatoes. Postharvest Biology and Technology 11(1): 57-62. Malundo, T., Shewfelt, R., and Scott, J. 1995. Flavor quality of fresh tomato (Lycopersicon esculentum Mill.) as affected by sugar and acid levels. Postharvest Biology and Technology 6(1-2): 103-110. Mencarelli, F. and Saltveit, M.E. 1988. Ripening of mature-green tomato fruit slices. Journal of the American Society for Horticultural Science 113: 742–745. Mencarelli, F., Saltveit, M.E. and Massantini, R. 1989. Lightly processed foods: ripening of tomato fruit slices. Acta Horticulturae 244: 193–200. Moline, H. 1976. Ultrastructural changes associated with chilling of tomato fruit. Phytopathology 66: 617. Nevins, D. and Jones, R. 1987. Plant Biology Volume 4. Tomato Biotechnology. Alan R. Liss, Inc. New York. Nielsen, S. 1998. Food Analysis 2nd edition. Aspen Publishers, Inc. Gaithersburg, MD.

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70 Noogle, G. and Fritz, G. 1983. Introductory Plant Physiology 2nd Edition. Prentice Hall Inc. New Jersey. O’Connor-Shaw, R., Roberts, R., Ford, A., and Nottingham, S. 1994. Shelf life of minimally processed honeydew, kiwifruit, papaya, pineapple, and cantaloupe. Journal of Food Science 59: 1202-1215. Palma T., Marangoni, A., and. Stanley, D. 1995.Environmental stresses affect tomato microsomal membrane function differently than natural ripening and senescence, Postharvest Biology and Technology, 6(3-4): 257-273. Poovaiah, B.W., 1986. Role of calcium in prolonging storage life of fruits and vegetables. Food Technology 40: 86–89. Rao, A. and Agarwal, S. 1999 Role of lycopene as antioxidant carotenoid in the prevention of chronic diseases: a review. Nutrition Research 19(2): 305-323. Saltveit, M. 2003. Is it possible to find an optimal controlled atmosphere? Postharvest Biology and Technology 27(1): 3-13. Sargent, S., 1997, Tomato Production Guide for Florida: Harvest and Handling. University of Florida Cooperative Extension Service. Institute of Food and Agricultural Sciences. February, 2003. Sargent, S. and Moretti, C. 2002. Tomato. In: Gross, K. Wang, C. and Saltveit, M. (eds.). The Commercial Storage of Fruits, Vegetables, and Florist and Nursery Stocks. United States Department of Agriculture Handbook 66. http://www.ba.ars.usda.gov/hb66/contents.html. February 2003. Selvarajah, S., Gaucho, A.D., and John, P. 2001. Internal browning in cold-stored pineapples is suppressed by a postharvest application of 1-methylcyclopropene. Postharvest Biology and Technology 23: 167–170. Sisler, E., Dupille, E., and Serek, M.. 1996. Effect of 1-methylcyclopropene and methylenecyclopropene on ethylene binding and ethylene action on cut carnations. Plant Growth Regulation 18: 79–86. Sisler, E. and Serek, M.1999. Compounds controlling the ethylene receptor. Botanical Bulletin Academia Sinica 40:1–7. Stedman, R. 2002. McSliced Tomatoes are here. Fresh-cut Magazine. Columbia Publishing. http://www.freshcut.com/. January 2003. Stommel, J.R. and Gross, K.C. 2001. Influence of polygalacturonase activity and cell wall composition on tomato anthracnose resistance. USDA, ARS. Maryland.

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71 Thimann, K. 1980. Senescence in plants. CRC Press, Boca Raton, FL. Wang, C. 1990. Chilling injury of horticultural crops. CRC Press, Boca Raton, FL. Watada, A., Herner, R.C., Kader, A., Romani, R., and Staby, G. 1984. Terminology for the description of developmental stages of horticultural crops. HortScience. 19(1): 20-22. Watada, A., Ko, N. and Minott, D. 1996. Factors affecting quality of fresh-cut horticultural products. Postharvest Biology and Technology 9(2): 115-125. Watada, A. and Qi, L. 1999. Quality of fresh-cut produce, Postharvest Biology and Technology 15(3): 201-205. Watkins, C., Nock, J., and Whitaker, B.D. 2000. Responses of early, mid and late season apple cultivars to postharvest application of 1-methylcyclopropene (1MCP) under air and controlled atmosphere storage conditions. Postharvest Biology and Technology 19: 17–32. Wills, R. and Ku, V. 2002. Use of 1-MCP to extend the time to ripen of green tomatoes and postharvest life of ripe tomatoes, Postharvest Biology and Technology 26(1): 85-90. Wills, R, McGlasson, Graham, and Joyce (ed). 1981. Postharvest : an introduction to the physiology and handling of fruit and vegetables Avi Publishing Co. Connecticut. Wu, T. and Abbott, J. 2002. Firmness and force relaxation characteristics of tomatoes stored intact or as slices. Postharvest Biology and Technology 24(1): 59-68.

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72 BIOGRAPHICAL SKETCH Minna Leibovitz was born and raised in Miami, FL. She graduated from Miami Sunset Senior High School in 1997. She received her Bachelor of Science degree from the Food Science and Human Nutrition Department at the University of Florida in 2001. Minna continued her education at the University of Florida and intends to receive her Master of Science degree in food science in August 2003.


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Title: Sensory and quality aspects of fresh-cut tomatoes as affected by stage of ripeness and postharvest treatment with 1-Methylcyclopropene (1-MCP)
Physical Description: Mixed Material
Creator: Leibovitz, Minna ( Author, Primary )
Publication Date: 2003
Copyright Date: 2003

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SENSORY AND QUALITY ASPECTS OF FRESH-CUT TOMATOES AS AFFECTED
BY STAGE OF RIPENESS AND POSTHARVEST TREATMENT WITH
1-METHYLCYCLOPROPENE (1-MCP)















By

MINNA LEIBOVITZ


A THESIS PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
MASTER OF SCIENCE

UNIVERSITY OF FLORIDA


2003

































Copyright 2003

by

Minna Leibovitz















ACKNOWLEDGMENTS

I would like to extend my gratitude Dr. Charles Sims. I could have never asked for

a more wonderful major professor. He always took time out of his crammed schedule to

discuss my project. His faith in my abilities as a student and a scientist encouraged me to

pursue a master's degree. I would also like to thank Dr. Talcott and Dr. Brecht for being

wonderful mentors; and for their never-ending assistance and advice for my project. I

would like to also thank Dr. Jeong for all of his help.

I would like to thank all of my panelists for their dedication to tasting tomatoes.

Without their help, there would not be a Chapter 4 or 5 to this thesis. I would especially

like to thank my lab mates: Bryan, George, Kurt, and especially Rena. Rena is an

amazing person. She helped out with my project even when she was juggling 12 million

other things to do. She has become one of my closest friends, always there to listen or

joke around. Without Rena, graduate school would not have been fun.

I also appreciate all of the support I have received from my friends old and new.

They have helped shape who I am, and made me more positive. They've also helped me

learn to not take life so seriously and have a lot of fun.

Last but not least, I'd like to thank my parents and my sisters for all of their

support and encouragement. My parents provided the foundation to become well

educated and successful, so I guess I'll start working on that successful part. I would also

like to thank Simon, for believing in me and keeping me grounded.
















TABLE OF CONTENTS
Page

A C K N O W L E D G M E N T S ................................................................................................. iii

ABSTRACT ....................................................... vi

CHAPTER

1 INTRODUCTION .......... ................................... ..... ...... 1..

2 LITERATURE REVIEW ............... ......... ............... ..................... ...............4

Structure and C om position ........................................ ................................. 4
P hy siology ......................................................................... . 6
Postharvest Physiology ............................................. .............. .... ......... 7
T o m ato Q u ality ..................................................................................................10
Q quality R equirem ents .................................................................................... 10
F lav or Q u ality ................................................................... ........... 10
Storage and R opening C conditions ................................................................... ... ..12
C h illin g Inju ry ............................................................................................... 12
Ethylene and Chilling Injury ............. ...................................... 14
Fresh-cut .......................................................................................... .....................16
Postharvest Treatm ents ................... .......................... ................ ........ 19
E thylene B lockers............. ............................................... ......... .......... 20
1-M ethylcyclopropene ................ ...... .... .......2.. ... ............... ...... 2 1
Postharvest Treatment of Climacteric Fruit with 1- MCP............................. 22
1-Methylcyclopropene and Nonclimacteric Commodities..............................24

3 M ATERIALS AND M ETHOD S ........................................ ......................... 26

M atu rity Stu dy .................. .................. ..... ..... ................................ .. ............. .... .. 2 6
1-Methylcyclopropene study: Sliced Fruit Treatment..............................................27
1-Methylcyclopropene study: Whole Fruit Treatment .............................................28
Quantitative D escriptive A analysis ........................................ ......................... 28
Q u ality E v alu action .... .......... .................................................. ............ .... 3 0
S statistic s ...................................... ................................................. .. 3 1









4 RESULTS AND D ISCU SSION ........................................... .......................... 32

S tu d y 1 ........................................... ...................................................... ............... 3 2
Light-red-stage Tom atoes: Replication 1 .................................... ............... 32
Sensory results................................................. 32
O their quality attributes ................ .... ...................... ........... ...................36
Red-stage Tom atoes: Replication 1.......................................... ............... 38
Sensory results................................................. 38
O their quality attributes ............................................................... ........ ..40
Light-red-stage Tom atoes: Replication 2 ................................. ................ 42
Sensory results................................................. 42
O their quality attributes ........................................................ .. .................. 45
Red-stage Tom atoes: Replication 2.......................................... ............... 45
Sensory results................................................. 45
O their quality attributes ............................................................... ........ ..47
Light-red-stage Tom atoes: Replication 3 ................................. ................ 49
Sensory results................................................. 49
O their quality attributes ........................................................... ................... 50
M icrobiological results........................................... .......................... 51
Red-stage Tom atoes: Replication 3 .......................................... ............... 51
Sensory results................................................. 51
O their quality attributes ........................................................... ................... 54
M icrobiological results........................................... .......................... 54
S tu d y 2 ....................................... .. .. ............ .. ....................................... 5 6
Light-red 1-MCP Treated Sliced Fruit vs. Control Fruit.............................. 56
Sensory results................................................. 56
O their quality attributes ......................................................... ................ 57
Red 1-MCP Treated Sliced Fruit vs. Control Fruit .......................... ..........57
Sensory results................................................. 57
Other quality attributes ................................... ..............59
S tu d y 3 ................................................................6 0

5 C O N C L U SIO N ......... ...................................................................... .......... ......65

L IST O F R E FE R E N C E S ................. ....... ........................................ .....................67

BIOGRAPHICAL SKETCH ......... ..................................................................72














Abstract of Thesis Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Master of Science

SENSORY AND QUALITY ASPECTS OF FRESH-CUT TOMATOES AS AFFECTED
BY STAGE OF RIPENESS AND POSTHARVEST TREATMENT WITH
1-METHYLCYCLOPROPENE (1-MCP)

By

Minna Leibovitz


August 2003

Chair: Charles Sims
Major Department: Food Science and Human Nutrition

Fresh-cut fruit products are partially prepared so that additional preparation is not

necessary for consumption by the consumer. Fresh-cut fruit are sliced when ripe, so they

are ready to eat with optimum color and flavor. This stage of development thus limits

their shelf lives. Fresh-cut products are highly perishable, because processing damages

the protective cells of the epidermis, making them vulnerable to discoloration,

dehydration, and microbial invasion. After slicing tomatoes, there may be a loss of

locular tissue, increase in water-soaked appearance, and deterioration, which hinders their

marketing and acceptability. The ethylene inhibitor 1-methylcyclopropene (1-MCP) is

effective in reducing the rate of ripening in many commodities such as apples, tomatoes,

and avocadoes. Our objective was to compare the quality and sensory characteristics of

light-red and red sliced fruit with whole fruit controls and slices treated with 1-MCP.









The stage of development affects the quality of fresh-cut fruit. Sliced light-red and

red-stage tomatoes stored at 20C were compared to whole fruit controls at 20C and 12C

over a period of 7-10 days. In both stages of development, sliced fruit displayed increased

water-soaked appearance and a loss in overall flavor intensity compared to whole

controls. Red-stage slices typically had better initial quality, but shorter shelf-lives than

light-red-stage slices.

Slicing tomatoes leads to increased ethylene production and respiratory activity;

consequently causing changes in quality. Light-red and red-stage fresh-cut tomatoes were

treated with 1 ppm 1-MCP at 5C for 24 hours to determine whether quality would be

extended. Sensory panel results concluded that overall there were no major differences

between control slices and 1-MCP-treated slices over a period of 7 days. Differences

between ripeness stages were more evident in attributes such as red color intensity, water-

soaked appearance, and firmness.

The physiology of sliced fruit differs from whole fruit. Whole red-stage tomatoes

were treated with 1 ppm 1-MCP at 200C for 24 hours, then sliced to determine whether

application of 1-MCP before slicing would be more effective in extending the shelf life of

sliced tomatoes. Panelists determined that control fruit had a less water-soaked

appearance than 1-MCP-treated fruit on Day 6 of storage and less fresh tomato aroma.

Overall, application of 1-MCP to whole fruit before slicing did not have a major impact

on the quality of sliced fruit throughout storage.














CHAPTER 1
INTRODUCTION

Fresh-cut fruits and vegetables are a growing part of the food industry. These

products are popular because of their convenience. Currently, there is great success in

marketing fresh-cut vegetables; and now the goal is to open the market to more fresh-cut

fruits. Watermelon, kiwifruit, and pineapple are already very successful as fresh-cut

items. However, complex physiological and biological changes occur when fruit are

sliced and stored (Watada et al.1996), limiting the growth and quality of the fresh-cut

fruit.

Fresh-cut fruits are more perishable than intact products because they have been

subjected to severe physical stress, such as peeling, cutting, and slicing, which causes

damage or removal of epidermal cells and wounding (Watada et al. 1996). This also can

increase susceptibility to invasion by pathogens, Fresh-cut products are held at low

temperatures (0-10C) to inhibit pathogenic growth.

More than 60 million tons of tomatoes are produced in the world each year.

Popularity and health benefits associated with tomatoes make them a viable commodity

for fresh-cut. According to a recent report in the Journal of the National Cancer Institute

(Giovannucci 1999) consuming tomatoes and tomato-based products reduced the risk of

cancer at a defined anatomic site, perhaps because oflycopene, an antioxidative pigment

found in tomatoes. The strongest evidence was for protection against cancer of the

prostate, lung, and stomach; though there was evidence of benefit for the pancreas,

colon, rectum, esophagus, oral cavity, breast, and cervix (Giovannucci 1999).









Officials at McDonald's Corporation announced that by the end of 2002, each of

their 13,000 U.S. stores will have the ability to purchase fresh-cut tomato slices from

suppliers rather than cutting them in-house (Stedman 2002). Purchasing pre-sliced

tomatoes would alleviate the managers' responsibility to decide when the fruit was ripe

enough to slice and serve to customers; and would hopefully improve product quality.

Tomatoes are climacteric fruit that ripen in response to ethylene and show a

characteristic rise in respiratory rate before the ripening phase. Stress factors (such as

wounding, flooding, chilling, disease, high temperatures and drought) seem to induce

ethylene synthesis, thus increasing the rate of ripening and senescence (Wang 1990).

When sliced, tomatoes elicit a wounding response. Wounding causes a surge in the

production of ethylene (Gil et al. 2001), which in turn causes the fruit to ripen faster.

Slicing also causes juice accumulation and microbial growth. Although shelf life can be

extended by cold storage, tomato tissue is sensitive to chilling injury.

Chilling injury is the physiological disorder caused by exposure of plants to low,

nonfreezing temperatures (Wang 1990). The symptoms of chilling injury in tomato fruit

are uneven ripening, surface pitting, increased susceptibility to fungal infection, loss of

aroma volatiles, and water-soaked areas on red tomato fruit (Hong and Gross 2001).

Although storing fruit at low temperatures causes chilling injury, chill-sensitive fruits

should be held at a temperature at which injury from chilling will be of less consequence

than the deterioration that results at non-chilling temperature (Watada et al. 1996).

So far, not much research has investigated the quality and stability of fresh-cut

tomatoes over storage. A valuable parameter to consider with fresh-cut tomatoes is

slicing at an earlier ripeness stage; and investigating effects on quality. Also, slowing the






3


ripening process and inhibiting chilling injury are possible ways to extend shelf life and

quality of fresh-cut tomatoes.

1-methylcyclopropene (1-MCP) has been found to inhibit the actions of ethylene;

and extend the storage life of many intact fruits and vegetables such as plums, apples, and

tomatoes (Blankenship and Dole 2003). The possible effects of 1-MCP on the sensory

quality and acceptability of fresh-cut tomato slices are of great interest to the fresh-cut

industry.














CHAPTER 2
LITERATURE REVIEW

Tomatoes are one of the most important commodities in America. According to the

Florida Tomato Committee (2001), the per capital consumption of fresh tomatoes in the

United States is approximately 17.7 lbs per year. Fresh tomatoes ranked number three in

consumer preference of vegetables, exceeded only by potatoes and lettuce.

During the 2000-2001 season, Florida growers harvested over 35,000 acres of

tomatoes for the fresh tomato market. Florida shipped in interstate commerce over 1.34

billion pounds of tomatoes. At the farm level, Florida tomatoes were valued at about

$490 million. The farm value of the tomato crop in Florida represents more than 29% of

the total value of all fresh vegetables produced in Florida each season. The total cost of

producing and harvesting tomatoes averages more than $11,600 per acre. Florida

produces almost all of the fresh-market field-grown tomatoes in the United States from

December through May each year (Florida Tomato Committee, 2001).

Structure and Composition

Characteristics of tomato fruit differ among the many tomato varieties. The tomato

is a berry with 2 to 12 locules filled with many seeds (Jones 1999). Processing tomatoes

(such as cherry, plum, or pear tomatoes) have two locules. Commercial cultivars for fresh

market have four to six locules. Large beefsteak-type tomatoes have more than six

locules. The extent of pollination affects the size and shape of the fruit, which determines

the number of seeds filling each locule (Jones 1999).









Water comprises 90% of the fresh weight of tomato fruit; and the size of the fruit is

influenced by the availability of water to the plant. The large amount of water also makes

the fruit perishable. As the tomato fruit develops, the percentage of fresh weight that is

sucrose decreases; while carbohydrates such as starch and reducing sugars increase

(Jones 1999). Sugars are mostly found in ripe fruit; and starches are found mostly in

unripe fruit (Wills 1981). In a ripe tomato fruit, about 5-7% of the tomato fruit is solids.

About half of the solids comprise sugars and one eighth is acids (Jones 1999). The main

sugar in tomatoes is glucose. Citric acid is the main acid in tomato juice; and the pH of

fruit is normally between 4.0 and 4.5 (Jones 1999). The pH of the fruit increases

throughout development.

Growing plant cells are surrounded by a primary wall made of polysaccharide. The

plant cell wall is a complex matrix containing cellulose, hemicelluloses, pectin, structural

proteins, and other components. The primary wall has many functions that provide

support and information to the plant. The primary cell wall is the source of many

biologically active signaling molecules (Noogle and Fritz 1983). These molecules are

used to determine downstream phenotypic expression of the plant.

As well as being popular with consumers, tomatoes are also highly nutritious. One

medium tomato provides 40% of the US RDA of vitamin C and 20% of the US RDA of

vitamin A, which comes from 8- carotene (Jones 1999). Tomatoes were ranked highest in

a comparison of crops and their contribution of nutrients to the diet (Wills 1981).

Tomatoes also provide potassium, iron, phosphorus, and some B vitamins, and are a good

source of dietary fiber. Ripe tomatoes are red in color because they contain lycopene, an

antioxidant.









Lycopene is a pigment synthesized by plants and microorganisms. Its singlet-

oxygen-quenching ability is twice as high as that of beta-carotene and 10 times higher

than that of alpha-tocopherol (Rao and Agarwal 1999). In a review discussing studies of

tomato lycopene and the incidence of prostate cancer risk, some studies have found a

lower incidence of prostate cancer in populations that consume large amounts of

tomatoes and tomato products. Consuming tomatoes and tomato products may decrease

the risk for developing prostate cancer (Rao and Agarwal 1999).

Studies suggest that lycopene from various tomato products is indeed associated

with the lowered risk of several types of cancers (Rao and Agarwal 1999). In

epidemiological studies correlating the incidence of cancer with the consumption of some

tomato products, it appeared that the intake of tomato products was inversely associated

with prostate cancer, and a high tomato intake resulted in reduced risk of digestive tract

cancer (Bramley 2000). But, the connection of diets high in lycopene with the reduction

of chronic diseases may be misleading because lycopene may not be the only anticancer

compound in tomatoes (Bramley 2000). More studies need to be completed before

anything definitive is stated concerning dietary intake of lycopene and lowered risks of

cancers.

Physiology

Fruits and vegetables have three physiological stages following initiation or

germination: growth, maturation, and senescence (Wills 1981). During growth and

maturation, the fruit is still attached to the plant. The growth period is the time when cell

division and enlargement take place, which is responsible for the final size of the

produce. Irreversible increases in physical attributes of a plant or plant organ occur

during growth (Watada et al. 1984). Another period of development for the plant is the









maturation period. It is during this period that the commodity develops characteristics to

obtain physiological and horticultural maturity. Physiological maturity is the stage of

development when a plant or plant part will complete ontogeny even when not attached

(Watada et al. 1984). A mature green tomato is considered physiologically mature; it can

be harvested and continue its lifecycle. Horticultural maturity is the stage of development

when a plant or plant part possesses the quality characteristics for utilization by

consumers (Watada et al. 1984).

For tomatoes, the horticultural maturity can range from mature green through full

ripe depending on the purpose of use (Sargent and Moretti 2002). In order to obtain

horticultural maturity for some commodities, salad and sandwich tomatoes, it is

necessary for the fruit to ripen.

Postharvest Physiology

The tomato is a climacteric fruit. Shortly before they begin ripening, climacteric

fruits experience a sharp rise in respiratory rates. At the beginning of ripening, tomatoes

experience a surge in respiration, shown with an increase in the production and release of

CO2 and ethylene, which peaks at about 10 days, and then declines (Jones 1999). In

tomatoes, the climacteric peak is reached before there is an appreciable accumulation of

lycopene, and when the red pigment accumulates, the rate of respiration decreases

(Thimann 1980). Climacteric fruit should be considered fully ripe after they reach their

respiratory climacteric (Wills 1981).

Ripening is the aggregation of processes that occur from the growth and maturation

stages of development through the early stages of senescence. Ripening changes are set

off and synchronized by a synthesis and sensitivity toward ethylene (Hobson 1987). It is

during this period that the esthetic and quality characteristics as expressed by the fruit.









Fruit ripening is a gradual process during which a fruit attains optimal eating quality

(Nevins and Jones 1987). In tomato, the process is characterized by the breakdown of

chlorophylls and the synthesis of lycopene, as well as increases in sensitivity to ethylene,

ethylene production, respiration, and the activity of polygalacturonase (Nevins and Jones

1987). Respiration and generation of ethylene increases with a peak at about 10 days and

then declines (Jones 1999).

When tomatoes ripen, they also soften. This is caused by changes in the structure

and composition of their cell wall. Cells of fruit can be large parenchymatous cells with

large air spaces between them (Thimann 1980). Changes in intensity of contact between

cells and structure of cell walls will affect texture (Thimann 1980). During ripening, cell

turgor is lost, middle lamella intercellular cement is broken down, and the cell walls are

thinned (Hobson 1987).

Many enzymes have been linked with cell wall weakening, such as

polygalacturonase (PG). Their activity is low or absent in unripe fruit and increases

during fruit ripening. In tomatoes, PG is found in the form of endo- PG. Endo-PG cleaves

the chains of polyuronides randomly. An increased solubility of cell wall polyuronides

occurs during softening in many fruits (Noogle and Fritz 1983).

There are six stages of tomato fruit development during ripening (for red fruited

cultivars): mature green, breaker, turning, pink, light-red, and red. Fruit change from

green to red, due to the conversion of chloroplasts, which contain chlorophyll to

chromoplasts, which have red or yellow carotenoids (Thimann 1980). Fruit are mostly

picked at the breaker stage of development, characterized by fruit, which are mostly

green, but showing pink color at the blossom end, and the placenta is pinkish in the fruit.









At this stage, fruit are still very firm, which makes them ideal for shipment. Mature green

fruit, which is picked prior to breaker stage, have a very long shelf life, but these less

mature fruit result in a significant loss in color and flavor when the fruit ripen (Jones

1999) compared to fruit that are left on the plant for longer prior to harvest.

Mature green and breaker stage tomatoes are usually ripened at 200C, and can be

accelerated by treatment with 100-150 ppm ethylene. Ethylene treatment shortens the

time after harvest required to bring about the climacteric rise affecting the respiration rate

at the climacteric peak (Thimann 1980). Ethylene-treated mature green tomato fruit will

develop red color at 5-7 days at 18-200C (Jones 1999).

Ripening is considered to start during the end of maturation, and the beginning of

senescence (Wills 1981), during which the structure and the composition of unripe fruit

change so that it will become acceptable to eat (Thimann 1980). Ripening and

senescence, the final stages of development for tomatoes, may occur on or off the plant.

Senescence is defined as the period when anabolic biochemical processes are replaced

with catabolic processes, which lead to aging and death of the tissue (Wills 1981), when

fruit are beyond ripe and breakdown and decay begin (Jones 1999). A major structural

change that occurs during ripening is the degradation of polyuronides by (PG), resulting

in a loss of galacturonic acid residues from the cell wall (Stommel and Gross 2001). A

net loss of arabinose and galactose residues also occurs from cell walls of ripening fruit.

Numerous lines of evidence support a role for PG in the fruit ripening process give a loss

of fruit integrity during senescence (Stommel and Gross 2001).









Tomato Quality

Quality Requirements

There are many key points to be considered in assessing the quality of tomatoes.

The minimum quality requirements for tomatoes after preparation and packaging include:

intact, fresh-looking, clean, free of excessive moisture, sound, and free of any foreign

smell and/or taste (Sargent and Moretti 2002). Also, the development and condition of

the tomatoes must enable them to withstand transport and handling, as well as arrive in

satisfactory condition in the place of destination. High quality fruit have a firm

appearance, uniform and shiny color, without signs of injury, shriveling, or decay

(Sargent and Moretti 2002). Tomatoes must also be packed in such a way that they are

protected properly. The materials used inside the package must be new, clean, and of a

quality such as to avoid causing external or internal damage to the produce.

Physical attributes are used to assess quality in fresh, vine-ripened tomatoes. Stem

and blossom scars, shoulders, color, and skin are all quality indicators (Hodges 1997).

The blossom scar should be small and tight, and the shoulders should be smooth and

round and the stem scar should be small and smooth. The color of the tomato should be

uniform with no blotchiness or scarring and fruit locules should be filled with gel, not air

spaces. Any deviation from the above physical descriptions can be a sign that the fruit has

been exposed to stress such as improper temperature storage (Hodges 1997). Fruit quality

is affected by ripeness stage, time of removal from plant, handling conditions and

frequency, and storage temperature and time (Jones 1999).

Flavor Quality

Fruit and vegetable flavor is the function of taste and aroma components (Jones

1999). The relationship between the acidity and soluble solids of tomato fruit is critical to









its perceived flavor (Jones 1999). Flavor quality is also affected by the stage of ripeness;

the stage at which harvest occurs has a major impact on the final flavor quality of the

tomatoes (Jones 1999) Fruit that remain attached to the plant longer are generally more

flavorful. Harvest maturity, storage temperatures, and internal bruising all negatively

affect tomato flavor and quality (Sargent 1997).

Malundo et al. (1995) found that taste (sweetness and sourness) and acceptability of

tomatoes was greatly affected by sugar and acid levels. The study also found that sugar

and acid concentrations did not significantly influence descriptive ratings for fresh

tomato impact. Tomatoes that had a pH of 3.74 and 0.80% titratable acidity had improved

flavor quality based on consumer acceptability ratings, when sugars were added. Also,

consumer acceptability ratings tended to decrease with added acid at a given sugar

concentration (Malundo et al. 1995).

Sensory characteristics of short-term stored tomatoes were evaluated by a trained

panel using Quantitative Descriptive Analysis. The study assessed 57 attributes and

consumer preferences in eight categories (Auerswald et al. 1999). Tomatoes stored for 4

or 7 days differed from fresh tomatoes in intensity of attributes (such as appearance of

outer and inner fruit, firmness to touch, smell, flavor aftertaste, and mouthfeel). Increases

in aroma attributes "tomato-like" and "sweetish" were found. Flavor attributes "sweet"

and "tomato-like" increased, as did off-flavor attributes "moldy" and "spoiled sweetish."

Sour and fresh-cut grass characteristics decreased. The trained panel found that with

increased postharvest storage period, the fruit were softer, juicier, pulpier, and less

"grainy" and "gristly." Consumers could tell a difference between the characteristics of

fresh and stored fruit on first impression, appearance, and smell. Surprisingly, the









appearance and smell of stored tomatoes were rated higher than fresh tomatoes

(Auerswald et al. 1999).

Storage and Ripening Conditions

Tomatoes for fresh consumption are commonly harvested at the immature or

mature green stages and shipped to retailers under controlled conditions, allowing long

distance shipment (Boukobza and Taylor 2002). Tomatoes should not be stored at

temperatures below 120C, according to the Florida Tomato Commission, whereby

"refrigeration kills aroma and flavor in fresh tomatoes (2001)." After commercial

packaging, tomatoes are placed on pallets and are either cooled at 200C for ripening, or

120C for storage. Optimum storage conditions depend on the maturity stage of tomatoes.

For ripening, optimum storage is 19-21 C. Tomatoes ripened at temperatures higher than

270C have reduced intensity of red color development, while temperatures less than 13C

impede ripening and may lead to symptoms of chilling injury (Sargent and Moretti 2002).

Chilling Injury

Chilling injury is the physiological damage that occurs in many plants and plant

products of tropical or subtropical origin when exposed to low, but not freezing

temperatures (Wang 1990). Exposure to such low temperatures has been shown to inhibit

photosynthesis, growth, pollination, fruit set, and fruit development (Lurie and Sabehat

1997). Fundamental qualities of fruit tissue, such as species, cultivars, growing

conditions, age, maturity, and exposure to stress all contribute to the development of

chilling injury symptoms; environmental conditions, such as temperature, duration of

exposure, relative humidity, and postharvest treatments also determine the intensity of

symptoms (Wang 1990). Chilling injury occurs in many fruit, including avocado,









pineapple, as well as tomato. The symptoms of chilling injury occur based on time and

temperature of exposure (Wang 1990). Uneven ripening, surface pitting, and increased

susceptibility to fungal infection, loss of aroma volatiles, and water-soaked areas on the

fruit surface are symptoms of chilling injury in tomato fruit. Chilling injury causes the

release of amino acids, sugars, and salts, which provide food for the growth of pathogens,

such as fungi, and may take the form of rotting in the fruit flesh (Wills 1981). Off flavors

and off odors are also characteristic of chill injured fruit. Chill injured fruit softening may

be related to changes that occur during their storage and possibly lead to mealy texture

(Palma et al. 1995). Mature green tomato fruit kept at a sufficiently long time at 12.70C

or colder will have poor color when ripe, and alternaria rot (Lorenz and Maynard 1988).

Ripe fruit kept colder than 70C will exhibit water soaking and softening decay (Lorenz

and Maynard 1988). Generally, greater chilling injury occurs to fruit that are exposed to

lower temperatures for longer periods of time (Wang 1990). Chilling injury symptoms

usually form after the fruit is placed at a warmer, non- chilling temperature.

The developmental stage is thought to influence plant sensitivity to chilling injury.

Fruit at the preclimacteric stage is generally more susceptible to chilling injury than at the

postclimacteric stage in fruit (such as avocado, papaya, melon, and tomato) (Wang 1990).

Moline (1976) found that after 10 days mature green tomatoes stored at 0C showed

visible signs of chilling injury (Wang 1990), and Cook (1958) found that ripe tomatoes

showed visible signs after 30 days under the same conditions.

A storage temperature for chill sensitive fruit is chosen as one low enough to

inhibit the ripening process and high enough to avoid chilling injury. For mature green

whole tomato fruit, this temperature is 120C, but ripening is not prevented at this









temperature, so the fruit can only be held for 2 weeks (Lurie and Sabehat 1997). Low but

nonchilling temperatures are commonly used to delay the onset of ripening in some

commodities. These conditions delay the production of ethylene and decrease the

sensitivity of fruit tissue to it. Tomatoes are stored at temperatures just above their

chilling injury threshold with ventilation, so that there is no accumulation of ethylene.

This allows the fruit to be transported for a longer period and ripened at a later time.

Whole mature green tomato fruit were stored at 20C for a period of 3 weeks to

determine when the fruit would be sensitive to chilling injury. The study found that at

during the first week, the tomatoes ripened as usual, but chilling injury symptoms were

present after 11 days. Rots began to appear in post-storage ripening and color

development was impaired (Lurie and Sabehat 1997).

In a study of tomato fruit chilled for 10 days at 20C, structural degradation was

shown to have occurred over storage (Moline 1976). Plastids of the membranes had

swollen, granal stacks deteriorated, and the internal lamellar tissues were distended. Also,

mitochondria were swollen, cristae had begun to lyse, and small vacuoles had developed

in the cytoplasm. All of these structural changes consequently caused loss of firmness.

After 15 days, plastids of fruit had deteriorated, the mitochondria were swollen and

cristae developed into vescicles. Fruit stored for 21 days at 20C had very few organelles

that were identifiable (Wang 1990), thus demonstrating that chill injury is detrimental to

plant tissue.

Ethylene and Chilling Injury

Ethylene is produced through a signal transduction pathway. L-methionine is

phosphorylated to S-Adenosylmethionine (SAM) through the activities of S-









Adenosylmethionine synthase. SAM is then converted into 1-aminocyclopropane-1-

carboxylic acid (ACC) by ACC synthase. ACC Oxidase then catalyzes the production of

ethylene from ACC. Formation of ACC is the rate limiting step in the production of

ethylene (Noogle and Fritz 1983). The concentration of ethylene in plant tissue is

dependent upon the rate of biosynthesis and on the diffusion of the gas (Noogle and Fritz

1983). Ethylene is neither "actively transported nor degraded" (Noogle and Fritz 1983).

Activation of ACC synthase, from for example auxin or wounding, can initiate the

production of ethylene. To inhibit the production of ethylene, breakdown or conversion

of ethylene synthesizing enzymes, or precursors has been effective. ACC deaminase

converts ACC to alphaketobutyrate, thereby preventing the formation of ethylene.

Aminoethoxyvinyl glycine, or AVG, also inhibits ethylene synthesis and physiological

responses caused by ethylene, such as chilling, wounding, and water-logging (Noogle and

Fritz 1983).

Ethylene has various effects on chilling injury of crops. In some fruit, ethylene

treatment reduces chilling injury; in other fruit, it does the opposite. Ethylene treatment

of mature green tomatoes before or after storage at chilling temperatures did not affect

the development of chilling injury symptoms (Kader and Morris 1975).

The effects of ethylene concentration on chilling injury of fresh-cut tomato have

been investigated. Water-soaked areas on the fruit flesh have been used as an indicator

for chilling injury in fresh-cut tomatoes (Hong and Gross 2000);(Gil et al. 2002). It has

been proposed that water-soaked areas occur more closely to the blossom than the stem

end of the fruit and may be related to differences in ripening stage (Gil et al. 2002).

Tomato slices exposed to high concentrations of ethylene had less water-soaked areas









than fruit stored in a low ethylene concentration environment (Gil et al. 2002), or slices

that had been treated with AVG (Hong and Gross 2000).

Fresh-cut

International Fresh Produce Association (IFPA) has defined fresh-cut produce as

"any fruit or vegetable or any combination thereof that has been physically altered from

its original form, but remains in a fresh state"(2001). Fresh-cut fruits and vegetables are

products that are partially prepared so that no additional preparation is necessary for use

by the consumer. The food service industry was initially the main user of fresh-cut

products, but supermarkets and warehouse stores have embraced them as well.

Consumers perceive fresh-cut fruit as being healthy, tasty, convenient, and fresh (Center

for Food Safety and Applied Nutrition ((CFSAN) 2001).

The Fresh-cut industry has experienced growth over the past ten years.

Consumption of fresh-cut products has increased, and spaces have been allocated in

supermarkets for product placement (Calvin et al. 2001). Fresh-cut fruit are sliced when

ripe so they are ready to eat with the optimum color and flavor levels acceptable to

consumers. This stage of development consequently limits their shelf- life. Ripe fruit are

more susceptible to microbial contamination, but in ripe tomatoes, it has been found that

high levels of polygalacturonase provided resistance to tomato anthracnose (Stommel and

Gross 2001). Handling and processing of fruit can create the opportunity for cross

contamination by foodborne pathogens. The fresh-cut industry must provide food safety

protection systems, that ensure the protection of consumers from microbiological hazards

(CFSAN, 2001), including implementation of Good Agricultural Practices (GAP's),

Good Manufacturing Practices (GMP's), and Hazard Analysis Critical Control Points









(HAACP). Usually, fresh-cut products are packaged in film packages or containers over-

wrapped with film (Watada and Qi 1999) and draw juice away from the fresh-cut item.

Fresh-cut products are highly perishable because processing damages the protective

cells of the epidermis, making them vulnerable to discoloration, dehydration, and

microbial invasion (Watada, et al. 1996). Also, ethylene synthesis is induced in fruit that

has been wounded (Hobson 1994), and may promote further ripening of the fruit. After

processing tomatoes for fresh-cut, there is a loss of locular tissue, watersoaking,

deterioration, and dessication, which hinders their marketing and acceptability (Sargent et

al. 2001). Temperature, atmosphere, and relative humidity are all instrumental in keeping

quality of fresh-cut products.

Fresh-cut products differ in their shelf- lives. When held at their recommended

temperature, they can last from 7 to 20 days depending on the commodity (Watada and

Qi 1999). Fresh-cut products are held for a short period of time at a temperature that

causes a slight amount of chilling damage, rather than a higher temperature causing a

greater amount of natural deterioration (Watada and Qi 1999). For most fresh-cut fruits,

including tomatoes, this temperature is around 5C. Gil et al. (2002) reported that sliced

tomatoes stored in modified atmosphere packaging had greater retention of quality up to

10 days when held at 0C. There were no significant differences in slices held at 0C or

5C for up to 7 days (Gil et al. 2002). Gil et al. (2002) also found that in order to maintain

quality of Fresh-cut tomato at 50C over a period of 10 days, a low permeability film is

required as well as an active MAP of 12 kPa 02 and 0 kPa Co2. They also found that use

of ethylene absorbent pads did not improve shelf life of tomato slices over a 10-day

storage period.









O'Connor-Shaw et al. (1994) reported that fresh-cut honeydew and muskmelons

should be held at the chilling temperature of 40C because the amount of chilling injury

was much less than the amount of natural deterioration that occurred at higher

temperatures (Watada and Qi 1999). Zucchini slices held at 0C had severe chilling

injury after 17 days of storage; 50 % of zucchini slices held at 50C had slight to moderate

amounts of lesions and decay related to chilling injury after 16 days of storage. Ninety

percent of samples held at 100C had natural browning and decay by the twelfth day of

storage (Izumi and Watada 1995)

In a comparison of respiration rates of intact and fresh-cut products of several fruits

and vegetables at 0, 5, 10, and 200C (Watada et al. 1996), sliced fruit at "optimum edible

maturity" had generally higher respiration rates than their whole fruit counterparts. Fresh-

cut tomatoes had higher respiration rates than whole tomatoes at temperatures 5C and

greater, showing the increase in ripening. The study also showed that "at the non-chilling

temperature, natural deterioration and infection by pathogens contributed more to

deterioration of quality than any injury that may have resulted due to chilling"(Watada et

al. 1996). The study concluded that chill sensitive fresh-cut fruits should be held at a

chilling temperature where injury from chilling will be of less consequence than the

deterioration that results at non-chilling temperatures.

Fresh-cut fruits have a complicated physiology because ripeness stage and ethylene

production reduces shelf- life (Artes et al. 1999). In a study examining fresh-cut tomato

quality at 20C and 100C, sliced tomatoes experienced an instantaneous, rise in CO2

production at 100C (Artes et al. 1999). It was shown that at 20C, partially ripe whole









tomatoes had respiratory patterns similar to that of fresh-cut fruit, however the respiration

of fresh-cut fruit increased significantly after 2 days at 100C.

Marketing of stored fresh-cut tomatoes has not been very successful because the

fruit exhibits characteristics that compromise the quality and acceptability of the fruit

after processing. The flesh becomes water-soaked, locular tissue is lost, and the fruit

deteriorates. Tomato slices are also prone to water loss and softening (Artes et al. 1999).

Destruction to the epidermis makes fresh-cut fruit more susceptible to microbial

invasion. Chlorine solutions are used to prevent microbial inoculation, but are ineffective

after pathogens have infected their host (Hong and Gross 1998). Fresh-cut products are

usually rinsed in 50-200 ppm chlorine solutions (Watada et al. 1996). However, the

chlorine solution does not eliminate all microorganisms and also can cause changes in

texture. For example, fresh-cut spinach washed with 50 ppm chlorine contained

mesophilic aerobic bacteria, psychrotrophic bacteria, Pserudomonadaceae,

Enterobacteriacae, Vibrionaceae, coliforms, and yeasts (Watada et al. 1996). Aqueous

calcium dips have been used to improve firmness of fresh-cut pears, zucchini squash, and

melon disks (Poovaviah 1986).Calcium reduces the action of cell wall degrading

enzymes and improves cell wall structure, and lessening fruit softening (Poovaviah

1986).

Postharvest Treatments

In order for many climacteric fruit to be ripened properly, a controlled ripening

treatment is used. Fruit are ripened to optimal quality under controlled conditions of

temperature and relative humidity, with the addition of ethylene. Whole green tomatoes

are kept at 20-210C and continuously exposed to 10 ppm ethylene continuously until ripe.









Another type of postharvest treatment is the application of ethylene blockers on

commodities to further control fruit ripening. These ethylene blockers bind to the

ethylene binding sites of fruits and inhibit the actions on ethylene. Many ethylene

blockers have been tested in attempts to extend the time it takes to ripen the fruit. This

could allow a longer transport period, and possibly delay ripening or decay in tomatoes

and other fresh-cut commodities.

Ethylene Blockers

Some compounds have been found to bind to the ethylene receptor in plants,

blocking ethylene action. This may be a new way of controlling ripening, senescence, and

other ethylene responses (Sisler and Serek 1999).

Other compounds such as cis-butene and cyclopentene were shown to inhibit

ethylene action. It was found that highly strained cyclic olefins were more effective in

blocking ethylene than less strained ones (Sisler and Serek 1999). These required

continuous exposure to plant tissue to be effective (Sisler and Serek 1999).

Some cyclic olefins seem to block ethylene responses in plants rather than induce a

response. 2,5-norbornadiene (2,5-NBD) blocked at the lowest concentration, but all of the

olefins tested required continuous exposure to be effective (Sisler and Serek 1999). The

relative effectiveness of these compounds was found to be proportional to their ability to

bind to silver ion, and ring strain was proposed to be an important factor in their

effectiveness (Sisler and Serek 1999).

It was found that some cyclopropenes counteract the effects of ethylene for 10-12

days in tissues given single exposure to the compounds at low concentrations (Sisler and

Serek 1999); other cyclopropenes block for less time or seem to be inactive (Sisler and

Serek 1999). Other compounds that are also effective ethylene inhibitors are carbon









dioxide, silverthiosulfate (STS), 2,5-norbomadiene (2,5-NBD), and diazcyclopentadiene

(DACP).

1-Methylcyclopropene

1-methylcyclopropene (1- MCP) is an active organic compound that interacts with

the ethylene receptor. It has ten times the affinity for the ethylene receptor than ethylene.

1-MCP is the breakdown product of DACP. For use on ornamental crops, Floralife, Inc.

formulated a powder that releases 1-MCP when mixed with water. The product was

approved by the EPA and is sold under the name Ethylbloc (Blankenship and Dole 2003).

For commercial application for use on edible crops, 1- MCP is applied under the trade

name Smartfresh (Agrofresh, Inc). Methylcyclopropene "will probably be the ethylene

inhibitor of choice for the immediate future and holds considerable commercial potential

since its active concentration of 0.5 ppb on carnations has not been reported to have toxic

properties" (Sisler and Serek 1999). Commodities are exposed to 1-MCP in its gaseous

form. It is typically applied in minute concentrations to commodities as a fumigant in

closed chambers at 20-25 C for 12-24 hour period.

At standard temperature and pressure (STP), 1-MCP is released from Ethylbloc

powder in approximately 20-30 minutes (Blankenship and Dole 2003). Temperature has

shown to affect the time for 1-MCP to be completely released. In a sealed chamber, one

third of the initial amount of the ethylene blocker remained in the chamber after 24 hours

treatment at 50C (Blankenship and Dole 2003). Various experiments have shown that

there is a relationship between concentration, time, and temperature, and applications at

low temperatures are not effective in some crops (Blankenship and Dole 2003). In

coriander, 1- MCP had no effect due to low sensitivity to ethylene at 5-10 C. In









penstemon, application of 1- MCP was not effective at 20C, but at 200C there was

complete protection from exogenous ethylene (Blankenship and Dole 2003). This was

also demonstrated in broccoli where 1-MCP application produced better results at 200C

than 50C, although an effect occurred at both temperatures (Blankenship and Dole

2003);(Ku et al. 1999).

The effective concentration of 1-MCP varies among commodities. In tomatoes, 7

ppb of 1-MCP blocked the color change for 8 days (Blankenship and Dole 2003); (Sisler

et al, 1996). The extension of the postharvest life of ripe tomatoes required 2 ppm 1-MCP

(Blankenship and Dole 2003).

Postharvest Treatment of Climacteric Fruit with 1- MCP

In a summary of physiological processes or disorders in fruits, vegetables, and

ornamentals that are affected or unaffected by exposure to 1-MCP, some climacteric fruit

were investigated. Apples, apricots ,avocados ,bananas, plums ,and tomatoes had

decreased ethylene production and respiration. Many of the fruits also maintained color

and firmness nearer to the pretreatment levels.

Softening is a problem associated with plums and apricots because they are picked

at a partially early stage and undergo rapid ripening and overripening (Dong et al. 2002).

Apricots can be divided based on their ethylene production (high, medium, and low).

"Canino" apricots are in the medium category of ethylene production. Plums can be

divided into two categories: 1) early rise in ethylene and CO2 production and 2)

suppressed climacteric production (as cited in Dong et al. 2002). "Royal Zee" plums are

in the latter. "Royal Zee" plums treated with 1 ppm 1-MCP retained most of their

firmness compared to control fruit at 5, 10, and 30 day storage times. However, after









storage, during the ripening period at 200C, the difference decreased and reached the

same level at 12 days. Canino apricots treated with Ippm 1- MCP did not experience

differences in firmness during storage period, but there were textural differences between

treatments during the ripening period. Therefore proper fruit maturity must be carefully

chosen for 1-MCP treatment (Dong et al. 2002).

Tomatoes are harvested early to reduce damage during transport, and then are

allowed to ripen. Ripening of green tomatoes is sped up by exposure to ethylene. Mature

green clarion tomatoes treated with various concentrations of 1-MCP at 200C showed a

delay in ripening relative to concentration of treatment over time (Wills and Ku 2002).

Green tomatoes treated with 1-MCP also showed a decrease in brix/acid ratio compared

to control fruits. 1-MCP also resulted in a reduction in respiration of mature green

tomatoes in the first 6-8 days after treatment, but inhibited the loss of titratable acidity

throughout the storage period. The results of the study suggests that 1-MCP treated

tomatoes might be more acceptable since their initial acid level remained the same

throughout storage but could not be investigated further due to the lack of registration of

the treatment at the time of the study (Wills and Ku 2002).

Apples also respond to the effects of 1-MCP. 1-MCP has also been shown to delay

ripening of apples (Baritelle et al. 2001), as well as improve their textural quality (DeEll

et al. 2001). The effects of 1-MCP on apples are dependent on duration and temperature

of treatment. "Empire" apples treated for only three hours showed initial improvement in

firmness retention, but after additional storage at 200C, their firmness did not differ from

control fruit (DeEll et al. 2001).









1-Methylcyclopropene and Nonclimacteric Commodities

Chilling injury is known to be associated with ethylene synthesis, even in non-

climacteric fruit (Selvarajah 2001). Pineapples, grapefruit, and oranges are examples of

nonclimacteric fruit. A postharvest application of 1 ppm 1-methylcyclopropene at 200C

for 18 hours on "Queen" pineapples that were stored at 100C for 3 weeks resulted in

minimal internal browning, and delayed shell ripening (Selvarajah 2001).

Color change and decrease in shelf life are also associated with ethylene exposure

in minimally processed nonclimacteric leafy Asian vegetables, such as Chinese mustard

and choy sum. These leaves experience senescence quickly because they lack ability to

obtain nutrients from other parts of the plant (Able et al. 2003). The presence of ethylene

may also enhance yellowing, an undesirable characteristic to the consumer. Application

of 1-MCP increased shelf life of mizuna and tatsoi (shown by a decrease in the color),

and also decreased browning in mizuna (Able et al. 2003).

It has been shown that ethylene has a part in the senescence of detached leaves.

Coriander leaves treated with .5 ppm or higher 1-MCP at 200C for 24 hours experienced

an inhibition in the loss of chlorophyll and soluble protein in the leaves and ethylene

production was increased with the treatment (Jiang et al. 2002).

Strawberries are nonclimacteric fruit that also respond to ethylene. Strawberries

exposed to ethylene have been shown to develop more red color intensity than those

stored in ethylene free air (Jiang et al. 2001). Strawberries treated with 1-MCP have

delayed rotting (Ku et al. 1999) and delayed changes in firmness (Jiang et al. 2001).

Overall, 1-MCP has shown to be an important application is extending the shelf life

of climacteric and non-climacteric whole fruit.






25


The objectives of this study are to determine how stage of ripeness affects the

sensory quality as well as shelf life of fresh-cut tomatoes, as well as determine whether 1-

MCP is a valuable postharvest treatment for extending the shelf life of fresh-cut

tomatoes.














CHAPTER 3
MATERIALS AND METHODS

Maturity Study

Pink stage "Florida 47" tomatoes were received from a packinghouse in Palmetto,

Florida and tomatoes were placed in a 200C cooler for ripening. After 2 days of storage at

200C, tomatoes were sorted based on color, indicative of ripeness stage. Ninety light-red

tomatoes were chosen based on their quality (skin color and firmness) and were further

separated into 3 groups: 20C whole fruit control (30), 120C whole fruit control (30), and

2C sliced (30).

Control fruit storage temperatures were chosen as a representative of whole fruit

stored at chill injury temperature (2C) as well as fruit at the threshold chill injury

temperature(12C). Sensory results showing similarities in attributes of sliced fruit with

whole fruit controls stored at 20C were indicative of chill injury symptoms, and

similarities of sliced fruit with whole fruit controls at 120C were indicative of senescent

responses of the sliced fruit.

Tomatoes were rinsed with a 100 ppm NaOCL and left to air dry. The whole fruit

controls were placed on sanitized trays at their respective temperatures in humidity-

controlled coolers. The third group of tomatoes was sliced at 200C using a sanitized

Tomato Saber (Prince Castle Inc. Part Number- 943 004. Model Number- (943). Slices

were approximately 1/2 inch in width. After slicing, the tomatoes were placed in

sanitized TupperwareTM Fridgesmart Containers individually. Both ventilation holes

were left open on the body of the container. The containers were then placed in a cooler









at 20C. Quality and sensory characteristics were assessed at 2-3 day intervals. Whole fruit

controls were sliced upon evaluation. The procedure was repeated for red-stage tomatoes

after they had ripened at 200C 3 days after the light-red-stage samples were initially

stored. All samples were stored for a period of 6 days.

The study was repeated two additional times. During the second replication,

"Florida 47" tomatoes were shipped from Quincy, FL to a Publix supermarket in

Gainesville, FL. Light-red-stage tomatoes were stored for a total of 10 days, and the red

tomatoes were stored for 6 days. During the third replication, "Mountain Spring"

tomatoes were shipped from Alabama to a Publix supermarket in Gainesville, FL. Both

light-red and red-stage tomatoes were stored for 10 days.

1-Methylcyclopropene study: Sliced Fruit Treatment

Light-red-stage premium "Florida 47" tomatoes were received from Publix

Supermarkets in Gainesville, FL. Thirty tomatoes were sorted based on physical quality,

as described above, and rinsed in a 100 ppm sodium hypochlorite solution and left to air

dry. Tomatoes were then placed at 50C for overnight storage to avoid cold shock. After

storage, the tomatoes were sliced using a sanitized Tomato Saber, and placed in sanitized

Fridgesmart containers individually. Both ventilation holes were left open, and then

placed in a sanitized sealed chamber at 50C. The treatment group was also sliced and

placed into Fridgesmart containers in a chamber at 50C. A 1 ppm solution of 1-MCP

was dispersed in the chamber and the chamber was then sealed. After 12 hours, the

control chamber was opened for approximately 1 minute, and then resealed. The

treatment chamber was also opened and another 1 ppm solution of 1- MCP was

dispersed, then the chamber was resealed. After the total treatment time of 24 hours









completed, samples were taken out of the chamber and were stored at 50C for 7 days.

Samples were evaluated every 2-3 days for quality characteristics. The study was

repeated with the addition of the red-stage of maturity, evaluation by the trained panel,

and microbial counts were measured.

1-Methylcyclopropene study: Whole Fruit Treatment

Red-stage "Florida 47" tomatoes were delivered from a packinghouse in Florida to

Gainesville, FL via Publix Supermarkets. Samples were sorted based physical quality.

Tomatoes were then separated into two groups (control group no 1-MCP treatment and

treatment group- 1-MCP treatment at 1 ppm for 24 hours), placed into chambers, and

treated as described in above section for sliced tomato MCP fruit. After treatment period,

samples were sliced and placed in 50C. A trained sensory panel evaluated samples and

microbial plate counts were completed every 2-3 days.

Quantitative Descriptive Analysis

A fifteen-member panel, made up of faculty and students of the University of

Florida, was trained for sensory analysis of tomato slices. Panelists were selected based

on their ability to distinguish between stored and fresh tomato slices and their availability

during the study.

In the first training session, panelists were given samples and chose descriptor

terms necessary to evaluate tomato quality. In the second training, panelists were

instructed on evaluating samples using a line scale and were presented with more tomato

samples at various ripeness levels. During the third through eighth training, panelists

were presented with standards of fresh and stored tomatoes for 13 attributes: red color

intensity, water-soaked appearance, fresh tomato aroma, off odors, firmness, juiciness,









mealiness, overall flavor intensity, overall ripe tomato flavor, off flavors, acidity,

sweetness, and overall acceptability.

Panelists compared samples with standards on the line scale. Different ripeness

levels of tomatoes were used as standards of red color intensity. Vine ripe tomatoes and

red-stage premium tomatoes were used as an anchor for high overall ripe tomato flavor.

Fresh sliced tomatoes and tomatoes stored for 3,5, and 10 days were used as standards for

various levels of fresh tomato aroma, off-odors, off flavor, and overall flavor intensity,

with fresh tomatoes as the high anchor for fresh tomato aroma. Sliced tomatoes stored for

21 days at 20C were used as the high anchor for water-soaked appearance and off odors.

Yellow and mature green tomatoes were used as examples of low acidity, and cherry

tomatoes were used as examples of high acidity and juiciness. Grape tomatoes were used

as examples for sweetness. Also, peaches and watermelons were used as examples of

mealiness. During the ninth training, panelists were taught how to rate samples using

CompusenseTM software (Compusense Inc. Ontario, Canada. Version 5.4). In subsequent

training between studies, panelists evaluated, and discussed samples at different ripeness

and storage levels as a refresher.

Panelists evaluated samples in individual booths at the sensory facility at the

University of Florida. The five middle slices of tomatoes were used for evaluation. The

stem and blossom ends of the tomato were discarded. Each panelist was given three half-

slices of tomatoes per sample. Panelists had slices from three different tomatoes in each

sample. Samples were placed side by side on trays in individual cups closed with lids.

Panelists were presented samples in random order for evaluation. The samples were

evaluated in duplicate. Between replications, panelists took a break to reduce fatigue.









Quality Evaluation

Prior to sensory evaluation, color and texture of slices were measured. There were

five samples per treatment group of color and texture. Color (reflectance) was

determined using a Minolta Colorimeter (Chromameter CR 200b) and was expressed in

L, a, and b, and converted into Hue values: (tan' (b/a)). Color was measured on the

fourth slice on the pericarp tissue. Slices from three different samples were taken for each

treatment in triplicate. Texture was determined using the Instron Universal Testing

Instrument with a compression test and a number nine probe. Texture was expressed as

maximum force used to compress sample 0.25 mm. Texture was measured also on the

fourth slice, and was repeated in triplicate. Slices from four different samples were taken

for each treatment group.

After sensory evaluation, remaining samples were homogenized for determination

of pH, titratable acidity, and soluble solids. pH measured on approximately 40 mL of

homogenate using a Fischer Scientific pH meter (Accumet Basic AB15) in triplicate.

Titratable acidity, expressed as percent citric acid was also determined using the Fischer

Scientific pH meter using 0.1N NaOH to titrate a 10 g homogenate per 90 mL distilled

water solution to a pH of 8.2.

Percent soluble solids, expressed as degrees brix (B) was determined using a

refractometer (Abbe Refractometer Mark II. Model 10480). Aerobic and yeast and mold

plate counts were completed through use of aseptic technique. Three individual slices per

treatment from different tomatoes were weighed and mixed with sterile phosphate buffer

in sterile sample bags to obtain a 10:1 dilution. Samples were stomached and then plated

onto 3M Petrifilm for aerobic bacteria, and yeasts and molds, respectively. Samples were

then serially diluted until 10-7. Samples were plated every 2-3 days of storage.






31


Statistics

All results were analyzed using analysis of variance on SAS statistical Software

(Version 8.2) Data was sorted by time and by treatment separately. Maturity levels were

analyzed independently of each other. After analysis of variance was completed and

significance between treatments was found (0.05), a Duncan's Multiple Range Test was

used for mean separation.














CHAPTER 4
RESULTS AND DISCUSSION

Study 1

Light-red-stage Tomatoes: Replication 1

Sensory results

Light-red-stage "Florida 47" tomatoes were sliced and held at 20C (2SLI) for 6

days. Whole tomatoes were also stored at 20C (2W) and 120C (12W) for 6 days. After the

designated storage period, whole samples were sliced and all treatments were evaluated.

Panelists evaluated treatments for 12 attributes: red color intensity, fresh tomato aroma,

off odors, firmness, mealiness, juiciness, overall flavor intensity, overall ripe tomato

flavor, off flavor, acidity, sweetness, and overall acceptability.

As shown in Table 1, many sensory attributes of the light-red-stage "Florida 47"

tomatoes had varied responses between treatments (20C whole, 120C whole, and 2C

sliced) and over time (0-6 days). For most attributes, differences between treatments

occurred only at Day 6 of storage.

For red color intensity, there was no difference between samples until Day 6. The

2C control as well as the sliced fruit had less red color intensity than the whole fruit held

at 120C. This indicates that the fruit at the holding temperature of 120C developed red

color over time, as an effect of normal ripening.

During the first replication, there was an increase in the water-soaked appearance

of the slices, which decreased the red color intensity of the sliced fruit. In subsequent

replications, the attribute "water-soaked appearance" was added.









There were no differences between treatments and throughout storage for fresh

tomato aroma. Fresh tomato aroma was maintained at a score of approximately 8.5

throughout storage. For off odor, there were no differences between treatments

throughout storage, but over time, the off odors did increase slightly for all samples.

Sliced fruit were lower in firmness compared to the whole controls by Day 3, and

over time, all samples experienced a decline in firmness. This indicates that the fruit at

2C most likely was still ripening and softening, but at a slower rate. This continuation in

ripening occurred because chill injury symptoms do not prevent the continuation of

ripening (Lurie and Sabehat 1997).

There were only minimal differences in juiciness between treatments and there

was no clear trend in juiciness during storage. Mealiness scores stayed relatively the same

over time, but at Day 6, the fruit held at 20C were less mealy in comparison to the whole

fruit controls at 120C.

There were no significant differences in overall flavor intensity at each evaluation

day, but overall flavor intensity tended to decrease over time. Overall ripe tomato flavor

of whole fruit controls stored at 120C increased on Day 6 .Off flavors did not differ

between treatments during storage, but over time, all samples displayed an increase in off

flavors.

Acidity decreased in sliced fruit at Day 3, and the acidity of the controls did not

differ much due to treatment at any storage period, but they did decrease over time for all

treatments. Sweetness remained constant throughout the study. Sweetness and acidity did

not seem to be important factors in assessing the shelf life of sliced and stored tomatoes.









The overall acceptability of the 20C whole controls and the 20C stored sliced fruit

was significantly lower than the whole fruit held at 120C around Day 6. Whole fruit

stored at 120C had better quality than other treatments because at 120C, fruit still ripen

and develop flavors (Lurie and Sabehat 1997), thereby improving quality.

Symptoms of chilling injury generally occur after the fruit has been held in low

temperatures for a period of a 7 days or more, and then transferred to approximately 200C

(Lurie and Sabehat 1997). There is a relationship between the time and temperature of

exposure of the plant to chill injury conditions in order for development of chill injury

symptoms(Wang 1990). After a critical number of hours have passed, the effects of

chilling on the commodity contribute less to the overall severity of the injury (Wang

1990). In this study with light-red tomatoes, the data from Table 1 indicates that the

critical time for development of chill injury symptoms (off-odors, less firmness, and

overall decay of the fruit) is around between 3 and 6 days.

Sliced fruit also seemed to experience chilling injury. Water-soaked areas occur

when the fruit has been sliced and stored. It generally occurs when fruit placed in chilling

injury temperatures (colder than 130C) and has not been placed back at room

temperature. (Hong and Gross, 2001). Hong and Gross (2001) used water-soaked

appearance as an indicator of chilling injury. In a fresh-cut tomato study, visual quality,

aroma, and texture all decreased over time after 10 days at 50C (Artes et al. 1999), which

concurred with sensory results in Table 1. These results also indicate that sliced tomatoes

are perhaps chill injured and have a short shelf life of approximately 6 days.













Table 4-1: The effects of treatment at each storage time on sensory attributes of sliced and whole light-red-stage "Mountain Spring"
tomatoes stored at 20C and 12 C


Time
(d) Treatment'
2W
0 12W
2SLI


Fresh
Red Color Tomato
Intensity Aroma
7.la2 8.6a
6.6a 8.4a
6.8a 7.2a


Off-
odors
2.4ab
2.3b
3.6a


Firmness
9.5a
9.8a
8.3a


Juiciness
8.7a
8.5a
8.1a


Overall
Flavor
Mealiness Intensity
6.4a 9.4a
5.7a 8.8a
6.6a 9.4a


2W
12W
3 2SLI


2W
12W
2SLI


Time Effect *


ns *


* ns


Overall
Ripe
Tomato
Flavor
7.8a
7.9a
7.8a


Off-flavors
1.8a
2.0a
2.5a


Acidity
9.4a
9.4a
9.5a


9.1a
7.1a
7.7a


6.7b
9.8a
7.8b


Sweetness
4.9a
5.0a
5.la


Overall
Acceptability
7.9a
8.0a
7.9a


9.4a
8.9a
6.0b


8.6a
8.3ab
6.7b


6.4ab
7.3a
5.6b


8.3a
7.4a
7.2a


4.6a
5.9a
5.8a


5.7b
6.5a
5.7b


8.2a
8.3a
7.9a


8.4a
8.3a
7.8a


6.8b
7.9a
6.9b


7.0b
8.8a
7.0b


7.4ab
8.8a
6.4b


7.0a
6.3a
5.7a


* *


3.8a
4.9a
5.3a


5.3a
5.9a
5.8a


7.3a
7.8a
5.4a


6.9b
8.4a
6.9b


1Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C
2Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3* indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect









Other quality attributes

There was no significant change in percent soluble solids for all treatments during

storage, as shown in Table 2. This is in agreement with sensory results for sweetness

during storage as shown in Table 1. Sensory results indicated there was no significant

change in sweetness for all treatments over time.

Sliced fruit maintained pH over time as shown in Table 2. As indicated in Table 1,

there was a decline in sensory acidity of samples over time and an increase in off-flavors.

Titratable acidity decreased slightly for both whole and sliced tomatoes at 20C over time.

This concurs with results from Artes et al. (1998), in that sliced tomatoes held at 20C had

decreases in titratable acidity.

Table 2 indicates that sliced fruit experienced a significant decrease in firmness

from an initial 1.47 N to 0.8 N by Day 3, and remained soft for the remainder of storage.

In comparison to the sliced fruit, whole fruit controls had a moderate decline in firmness

over time. Initially, their firmness was approximately 1.4 N, and by Day 3 they had

decreased to 1.0 N. After 3 days, their firmness continued to decrease, and the whole fruit

were as soft as the sliced fruit. This seems to indicate that that the whole controls stored

at 20C were beginning to display symptoms of chill injury, and the controls stored at

120C were beginning to become over ripe.

Compression measurements of sliced and stored light-red tomatoes concurred with

Watada and Qi (1999) in that there is a definite loss of firmness in sliced fruits over time

but there was still a great deal of variability regarding firmness of slices. As noted in a

fresh-cut study by Artes et al. (1999), variability arises due to location of the slice relative

to the ends of the fruit.









Although slices were chosen from the middle of the fruit, there was still a great

deal of variability in firmness. Parts of the slices that were in contact with the

Fridgesmart package were less firm. Also, the degree of water-soaked appearance in

different areas of the flesh cause great amounts of variability in the firmness of the slice.

Instron measurements showed that whole fruit controls held at 120C were the least

firm. This does not agree with the sensory firmness results as indicated in Table 1, where

sliced fruit have the lowest firmness during storage. Wu and Abbott (2002) conducted a

study where they surveyed many different methods of firmness measurements of sliced

tomatoes. Possibly a different method, such as using force relaxation on the slices, where

the impact of viscoelastic changes is taken into consideration (Wu and Abbott, 2002)

would have been more effective. In general, there was greater variability within

treatments than between treatments.

The L value, or degree of lightness, decreased in the sliced fruit over time, as

shown in Table 2. The fruit that were kept at chill injury temperature (20C) maintained

their L value. The "a" value has been used as an indicator of red color development

(Artes et al. 1999). Tomatoes stored at 20C also had increased "a" values, indicating a

slight increase in red color over time, and they maintained their hue value throughout

storage. Sliced fruit maintained its red color and hue throughout storage. Hue refers to the

characteristic of a color that distinguishes red from yellow from blue (Color Cube, 2000).

This agrees with sensory data as shown in Table 1.Sliced fruit and whole fruit held at 20C

had less red color intensity than whole fruit held at 120C. In light-red tomato fruit (fruit

with outside hue angle's between 65 and 75), it has been found that juice color

measurement maintained for sliced tomatoes held at 20C (Artes and other, 1999).










Table 4-2:The effects of treatment on quality attributes of sliced and whole light-red-
stage "Florida 47" tomatoes stored at 20C and 12C
Treatment' Time % soluble pH g citric Compression L a Hue (tan1
(d) solids acid/100m Force (N) (b/a))
L

12W 0 4.5a2 4.4a 0.40a 1.47a 43.2a 9.9a 52.5
2W 0 4.6a 4.4a 0.40a 1.5a 43.la 10.3a 53.6a
2SLI 0 4.7a 4.4a 0.40a 1.38a 41.1a 11.7a 50.3a

12W 3 4.5a 4.4a 0.40a 1.01a 38.3ab 12.4a 47.5a
2W 3 4.6a 4.4a 0.36b 1.01a 41.1a 10.3ab 50.7a
2SLI 3 4.7a 4.4a 0.35b 0.80b 34.9b 9.7b 51.6a

12W 6 4.6a 4.3a 0.40a 0.67b 39.5b 14.la 42.8b
2W 6 4.6a 4.3a 0.31b 0.75b 46.2a 11.0b 50.8a
2SLI 6 4.6a 4.3a 0.31b 0.96a 40.lb 10.9b 47.4ab

Time ns3 ns *
Effect
1.Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced
fruit held at 20C
2 Means within a storage time followed by the same letter are not significantly different (Duncan's
Multiple Range Test, 0.05).
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage
time effect


Red-stage Tomatoes: Replication 1

Sensory results

As for the light-red-stage, red-stage "Florida 47" tomatoes were either sliced and

held at 20C or kept whole at either 12 or 20C for a storage period of 6 days. After the

designated storage period, whole tomatoes were sliced and all treatments were evaluated.

As indicated by Table 3, many attributes for red-stage tomatoes experienced changes

over time, as well as differences compared to other treatments. In red-stage tomatoes,

most changes were noticeable by Day 3. This is three days earlier than in light-red-stage

tomatoes, as shown in Table 1.









Red color intensity had variable results over time for red-stage "Florida 47"

tomatoes. At Day 6, whole fruit controls held at 20C had less red color intensity than the

other two, indicating possible chilling injury.

Fresh tomato aroma did not differ due to treatment during storage, but decreased

over time for all treatments. Off odors were higher in sliced fruit by Day 3 and whole

fruit controls stored at 12 C had less off odors than sliced fruit and whole fruit held at 2 C

by Day 6. The whole fruit stored at the holding temperature of 12C, had development of

off-odors.

Sliced fruit held at 20C were less firm than whole fruit controls by Day 3 of

storage. This indicates that the whole fruit controls held at 120C might have become over

ripe, while senescence in the sliced fruit led to deterioration of the pericarp.

Juiciness did not differ due to for most treatments over time, but decreased in

sliced fruit at Day 3 of storage. There was also a loss of juiciness for all samples

throughout time. Whole fruit controls were either chill injured (20C), or overripe (120C),

causing a loss in cell turgor and resulting in less juiciness. At Day 3, whole fruit controls

at 20C were mealier than other treatments, but at Day 6, all fruit had the same level of

mealiness, indicating that there is no general trend in the production of mealiness.

The overall flavor intensity and ripe tomato flavor of slices declined at Day 3. At

Day 6, the whole fruit held at 120C displayed less overall flavor intensity than the fruit

held at chilling temperatures. This is most likely due to the fruit becoming over-ripe. All

treatments had less ripe tomato flavor by Day 6 of storage.

Sliced fruit held at 20C had increased levels of off flavors on Day 3, while whole

fruit held at 2C had more off flavors by Day 6. All treatments generally maintained









acidity over time. Samples held at 20C decreased in sweetness over time beginning

around Day 3, but by Day 6, all samples had lower sweetness than initial levels. Sliced

fruit displayed lower overall acceptability in comparison to whole controls at Day 3, but

at Day 6, all fruit were less acceptable than initially. Other quality attributes

Other quality attributes

As indicated in Table 4, all treatments maintained their soluble solids at

approximately 4.6 B. This agrees with findings from Gil et al. (2002). Sliced tomatoes

stored in MAP maintained soluble solids regardless of temperature of storage and

permeability of film. Panelists found a loss in sweetness and an increase in off-flavors for

all treatments during storage, as indicated in Table 3. Possibly the increase in off-flavors

resulted in a loss of sweetness perception.

Whole fruit controls and sliced fruit held at 20C maintained pH over storage as

shown in Table 4. As indicated by Table 3, panelists detected a slight decrease in acidity.

Titratable acidity also decreased for sliced for sliced tomatoes stored at 20C. This agrees

with findings from Gil et al. (2002); who found a decrease in pH and titratable acidity in

sliced fruit.

All treatments of fruit were not firm, having compression force of 0.7 N. This

texture did not change much over time and did not result in significance between

treatments, as shown in Table 4. Gil et al. (1999) concluded that a loss of firmness of

fresh-cut tomato slices was probably linked to ripeness stage of whole fruit. As in the

light-red-stage, this did not concur with the sensory results as shown in Table 3. Sliced

fruit and whole fruit controls stored at 120C were less firm than whole fruit controls held

at 20C. This indicates that perhaps sensory results are more sensitive than mechanical













Table 4-3:The effects of treatment at each storage time on sensory attributes of sliced and whole red-stage "Florida 47" tomatoes
stored at 20C and 12C


Time
(d) Treatment'
2W
0 12W
2SLI


2W
3 12W
2SLI

2W
6 12W
2SLI


Red
Color
Intensity
11.9a2
11.6a
12.0a


9.7a
10.0a
8.9b

10.5b
11.8a
11.4a


Fresh
Tomato
Aroma
10.2a
10.4a
10.2a


9.2a
9.1a
8.1a

9.1a
9.9a
8.6a


Off-
odors
3.9a
3.3a
3.5a


2.5b
2.7b
5.2a

4.4a
2.5b
4.4a


Firmness
9.0a
8.0a
7.8a

8.4a
8.5a
5.8b

10.2a
7.9b
6.3c


Juiciness
9.1a
9.2a
9.5a


7.9a
8.2a
6.0b

8.2a
7.6a
7.8a


Overall
Flavor
Mealiness Intensity
6.3a 9.2a
6.6a 9.1a
6.7a 9.2a


7.0ab
6.9b
8.5a

5.7a
6.5a
6.5a


9.2a
9.2a
6.6b

9.4a
7.5b
9.4a


Time Effect3 *
1.Treatments: 2W= whole fruit control held at 20C;


* ns


* *


* *


12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C


2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect


Overall
Ripe
Tomato
Flavor
10.la
9.9a
10.0a


Sweetness
6.1a
6.0a
7. 1a


Overall
Acceptability
9.7a
8.8a
9.7a


Off-
flavors
2.0a
1.9a
2.2a

3.0b
2.0b
5.1a

4.2a
3.0b
3.3ab


Acidity
7.5a
7.4a
7.5a


8.0a
7.7a
6.6a

7.0a
5.7a
5.8a


5.5ab
6.6a
5.1b

4.0a
4.0a
4.7a










Instron compression results, or the Instron measurements were inadequate for detecting

firmness changes in sliced tomatoes.

Over time, all fruit generally maintained their "a" value, indicating no further red

color development of red-stage tomatoes, as shown in Table 4. Sliced fruit experienced a

decrease in L value over time. This occurred when there was an increase in water-soaked

appearance of slices.

Table 4-4:The effects of treatment on quality attributes of sliced and whole red-stage
"Florida 47" tomatoes stored at 20C and 12C
Hue
% soluble g citric Compression (tan1
Treatment' Time (d) solids pH acid/100mLForce (N) L a (b/a))

12W 0 4.6a 4.4a 0.35a 0.72a 42.6a 16.3a 41.9a
2W 0 4.6a 4.4a 0.35a 0.70a 41.5a 14.7a 41.5a
2SLI 0 4.6a 4.4a 0.35a 0.69a 39.0a 16.7a 40.8a

12W 3 4.6a 4.4a 0.36a 0.73a 40.8a 15.2a 39.8a
2W 3 4.5b 4.4a 0.36b 0.64a 42.9a 15.2a 40.3a
2SLI 3 4.5b 4.4a 0.34b 0.61a 35.9b 15.2a 37.7a

12W 6 4.6a 4.4a 0.36a 0.48a 38.2b 16.la 40.9a
2W 6 4.6a 4.4a 0.35a 0.55a 42.4a 16.1a 41.2a
2SLI 6 4.6a 4.4a 0.33b 0.46a 32.6c 14.2a 34.0b

Time Effect3ns ns *
'Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced
fruit held at 20C
2Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple
Range Test, 0.05)
3 indicates a significant storage effect at the 0.05 level. iin' indicates a non significant storage time
effect.


Light-red-stage Tomatoes: Replication 2

Sensory results

In replication 2, light-red ""Florida 47"" tomatoes (average hue=55) experienced

similar sensory responses during storage as the first replication, as indicated in Table 5.

The time of storage was increased from 6 to 9 days. At 6 days, sliced fruit were still









relatively acceptable to panelists. It was thought that a longer storage period might result

in greater differences in attributes between treatments.

Beginning at Day 3, there was a trend for less red color intensity for whole fruit

controls and sliced fruit stored at 20C. Water-soaked appearance remained relatively

constant throughout time for whole fruit controls, but sliced samples increased in their

watersoaking over time.

All treatments maintained their fresh tomato aroma over time and there were no

differences between treatments at each storage period. Over time, off-odors generally

increased throughout storage.

Samples decreased in firmness over time. Sliced fruit held at 20C decreased in

juiciness during storage comparatively to the whole controls at 20C and 120C, showing

characteristic signs of desiccation that occur to sliced fruit. There were no differences

between treatments at respective storage times for mealiness, but all samples increased in

mealiness throughout storage.

Overall flavor intensity of all samples did not change throughout the study the

study. Overall ripe tomato flavor, however, increased over time for all samples. There

were no differences between treatments for off flavors, but all samples showed increased

off flavors over time. Acidity decreased over time for all samples. Sweetness increased at

Day 6 for all samples and fruit held at chilling temperature were rated as the highest in

sweetness. All samples decreased in acceptability over time.













Table 4-5: The effects of treatment at each storage time on sensory attributes of sliced and whole light-red-stage "Florida 47" tomatoes
stored at 20C and 12C


Time
(d) Treatment'
2W
0 12W
2SLI


2W
3 12W
2SLI


2W
6 12W
2SLI


2W
9 12W
2SLI


Red
Color
Intensity
7.6a2
8.0a
8.2a


6.6b
10.5a
8.0b


8.6b
11.0a
7.5b


5.3b
9.7a
6.6b


Water-
soaked
Appearance
2.3a
2.1a
1.9a


Fresh
Tomato
Aroma
9.0a
9.3a
9.1a


3.2b
2.9b
6.5a


8.0b
10.2a
9.2a


11.la
9.8a
9.4a


Off-
odors
1.6a
1.4a
1.8a


3.0ab
1.4b
3.3a


3.9a
2.2a
3.6a


2.6a
3.4a
4.6a


Overall
Overall Ripe
Flavor Tomato
Firmness Juiciness Mealiness Intensity Flavor
9.3a 8.8a 3.6a 8.1a 8.3a
8.3a 9.0a 3.la 9.1a 8.8a
8.9a 9.la 3.4a 8.8a 8.2a


10.3a
11.7a
8.0b


3.1a
2.0b
3.0ab


10.0a 8.3a 3.3a
8.6a 8.8a 3.2a
9.3a 8.0a 3.7a


8.7a
8.5a
6.9b


9.3a
9.8a
8.7a


Off-
flavors
1.8a
2.3a
2.6a


Overall
Acidity Sweetness Acceptability


5.3a
5.0a
4.4a


8.4ab 3.5a 9.1a 4.la


9.7a
8.2b


9.9a 10.4a
10.0a 11.3a
8.5a 9.3a


2.8a 8.la 4.0a
4.3a 8.5a 3.la


7.6a
8.0a
5.7b


10.2a
8.5ab
7.5b


Time effect3 *


ns ns ns


ns


1.Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C
2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect









Other quality attributes

Sliced fruit and whole fruit controls at 20C maintained their soluble solids, as

indicated in Table 6. Sensory results also indicated that there was no significant change in

firmness for all treatments throughout storage, as indicated in Table 5.The pH of

treatments generally followed the same trends as in replication 1; all fruit basically

maintained pH, as shown in Table 6. Panelists did not indicate a change in acidity for all

treatments throughout storage, as indicated in Table 6, but there was a slight loss in

titratable acidity for sliced fruit and whole fruit held at 20C.

As in replication 1, sliced fruit exhibited an earlier decrease in firmness over time.

Around three days of storage, their firmness decreased from 1.4 N to 0.8 N, as shown in

Table 6. The whole fruit controls held at 20C and 120C maintained their firmness over

storage.

Both whole controls displayed an increase in a value, indicating an increase in red

color development. L values were maintained over time, indicating that the degree of

water-soaked appearance was less in comparison to red-stage fruit at Day 6. All

treatments maintained their hue value throughout storage, indicating there was no major

change in color development throughout storage, as indicated in Table 6.

Red-stage Tomatoes: Replication 2

Sensory results

In replication 2, red "Florida 47" tomatoes (average hue= 44) had similar sensory

results as replication 1, as shown in Table 7. Sliced fruit and whole fruit controls held at

120C maintained their red color intensity over time, while whole fruit controls held at

2C lost their red color intensity. All fruit increased in watersoaking during storage, and










red-stage fruit had a greater degree of water-soaked appearance than light-red-stage fruit.

Sliced fruit exhibited the most watersoaking throughout storage. Whole fruit controls

maintained their fresh tomato aroma, while sliced fruit had a decline in fresh tomato

Table 4-6:The effects of treatment on quality attributes of sliced and whole light-red-
stage "Florida 47" tomatoes stored at 20C and 12C
g citric
% soluble acid/100m Compression Hue (tan1
Treatment' Time (d) solids pH L Force (N) L a (b/a))
12W 0 4.5a2 4.3a 0.40a 1.48a 47.6a 16.0a 43.6a
2W 0 4.5a 4.3a .40a 1.43a 45.6a 14.0a 47.5a
2SLI 0 4.5a 4.3a .40a 1.41a 47.4a 14.3a 48.7a

12W 3 4.5a 4.3a .39a 1.14a 45.8a 18.0a 39.2b
2W 3 4.5a 4.3a .36b 1.26a 46.6a 14.5c 45.1a
2SLI 3 4.6a 4.3a .35b 0.83b 46.1a 16.2b 42.4a

12W 6 4.7a 4.3a .39a 1.30a 43.9b 21.1a 40.1a
2W 6 4.6a 4.3a .31b 1.29a 46.lab 17.6b 42.1a
2SLI 6 4.5b 4.3a .31b 0.89b 47.5a 13.8c 43.8a

12W 9 4.7 4.3a .37a 1.16a 44.9b 18.4a 41.3b
2W 9 4.6 4.3a .36a 0.96ab 48.7a 16.3ab 43.9a
2SLI 9 4.5 4.3a .32a 0.88b 44.8b 14.8b 49.lb

Time
effect3 ns ns ns
1Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced
fruit held at 20C
Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple
Range Test, 0.05)
3 indicates a significant storage effect at the 0.05 level. iin' indicates a non significant storage time
effect.


aroma over time. Sliced fruit also had an increase in off odors relative to the whole

controls over time.

Firmness was maintained throughout storage for all treatments. Juiciness

decreased for all treatments over time, showing no differences between treatments.

Mealiness increased in sliced samples and maintained relatively high for whole controls.









Overall flavor intensity decreased in sliced samples and maintained in whole fruit

controls. Overall ripe tomato flavor decreased in whole fruit controls at 20C and sliced

fruit; ripe tomato flavor slightly increased for whole fruit at 120C during storage. Off

flavors were higher in sliced fruit than whole fruit controls and increased over time.

Acidity was maintained in whole fruit controls at 120C, and decreased in sliced fruit and

whole fruit controls at 20C. There was a loss in sweetness in sliced samples over time as

well as compared to the other treatments. Sliced fruit had less acceptability than whole

fruit controls at Day 3 and were not acceptable at Day 6 of storage.

Other quality attributes

All treatments maintained their soluble solids over time (Table 8). According to

the sensory results in Table 7, sliced samples were less sweet compared to the other two

treatments. This also agreed with replication 1. The increase in off-flavors, might again

have caused decrease in the perception of sweetness.

Table 8 indicates that all treatments maintained their pH over time, as in replication

1, but had a slight decrease in titratable acidity. This agrees with sensory results shown in

Table 7. Panelists noted a loss in acidity at Day 6 for sliced tomatoes held at 20C.

As in replication 1, Instron compression measurements demonstrated that all

treatments maintained their firmness throughout storage (Table 8). These results agreed

with sensory results as indicated in Table 7. Results also support the idea that the loss of

firmness of fresh-cut tomatoes slices is probably linked to ripening stage of whole fruit

(Gil, 1999). Sliced fruit decreased in L value compared to whole fruit controls stored at

2C and 120C, as shown in Table 8. Water-soaked appearance, as in replication 1, likely

caused the decrease in L value of sliced tomatoes stored at 20C.













Table 4-7:The effects of treatment at each storage time on sensory attributes of sliced and whole red-stage "Florida 47" tomatoes
stored at 20C and 120C.


Time
(d) Treatment'
2W
0 12W
2SLI

2W
3 12W
2SLI


Red
Color
Intensity
9.5a2
9.6a
9.7a

8.6b
9.3b
10.5a


Water-
soaked
Appearance
3.4a
4.0a
3.7a

3.3a
3.la
4.5a


Fresh
Tomato
Aroma
9.7a
10.5a
10.5a

10.0a
9.8a
8.0b


Off-
odors
2.5a
2.9a
2.7a

2.2b
2.9ab
4.1a


Firmness
9.3a
8.9a
9.6a

9.5a
10.0a
13.7a


Juiciness
9.1a
9.0a
8.9a

8.7a
8.8a
8.7a


Overall
Flavor
Mealiness Intensity
3.9a 8.7a
4.la 8.4a
3.6a 9.2a

3.9b 9.0a
3.4b 9.2a
5.la 7.7b


6.9a 4.5ab
8.3a 3.6b
8.3a 5.2a


9.lab
9.8a
6.6b


4.6b
2.8b
8.7a


8.6a
10.la
8.5a


7.7a
10.7a
7.4a


3.5b 4.4a 5.4a 6.8a
3.3b 6.0a 4.3ab 6.4ab
6.9a 4.7a 2.9b 3.7b


Time effect3 *


* ns


* *


'.Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C
2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect


2W
6 12W
2SLI


Overall
Ripe
Tomato
Flavor
9.1a
8.9a
8.8a

9.1a
9.3a
7.5b


Off-
flavors
3.2a
2.9a
2.9a

2.6ab
2.0b
3.4a


Acidity
6.4a
6.1a
7.2a

7.2a
6.9a
6.6a


Sweetness
5.6b
6.3ab
6.9a

6.0ab
6.1a
4.7b


Overall
Acceptability
7.8a
8.0a
7.la

8.4a
8.4a
6.4b










Light-red-stage Tomatoes: Replication 3

Sensory results

Light-red "Mountain Spring" sliced tomatoes (average hue= 50) experienced a

loss in quality compared to whole fruit controls. "Mountain Spring" Tomatoes were

substituted for "Florida 47" tomatoes because of their availability at the time of this

study.

As shown in Table 9, there was a loss of red color intensity over time for sliced and

whole tomatoes held at 20C. Sliced fruit exhibited an increased in water-soaked

Table 4-8:The effects of treatment on other quality attributes of sliced and whole red-
stage "Florida 47" tomatoes stored at 20C and 12C
g citric
Time % soluble acid/100 Compression Hue (tan'
Treatment' (d) solids pH mL Force (N) L *a (b/a))
12W 0 4.6a2 4.4a .35a 0.99a 43.8a 17.6a 44.5a
2W 0 4.6a 4.4a .35a 0.96a 43.3a 18.2a 43.8a
2SLI 0 4.6a 4.4a .35a 0.83a 44.6a 20.7a 38.5a

12W 3 4.7a 4.4a .35a 0.93a 45.0a 19.6a 45.0a
2W 3 4.6b 4.4a .35a 0.99a 45.3a 20.3a 45.3a
2SLI 3 4.6b 4.4a .34a 0.78a 44.4a 18. b 44.4a

12W 6 4.7a 4.4a .35a 0.84b 45.4a 19.9a 43.2a
2W 6 4.6b 4.4a .35a 0.99a 45.7a 18.9ab 41.5a
2SLI 6 4.6b 4.4a .31b 0.80b 42.4b 17.9b 39.4a

Time
effect3 ns ns ns
1Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced
fruit held at 20C
2Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple
Range Test, 0.05)
3 indicates a significant storage effect at the 0.05 level. iin' indicates a non significant storage time
effect.


appearance over time and were more translucent with respect to whole fruit controls.

Whole fruit controls held at 20C, as well as sliced fruit, had decreased in fresh tomato









aroma over time and were less fresh than whole fruit controls held at 120C. The reverse

held true for off- odors.

Whole fruit controls at 120C were firmer than treatments held at 20C. Juiciness was

maintained over time for all treatments. Treatments held at 20C experienced increased

mealiness compared to controls at 120C. The overall flavor intensity and overall ripe

tomato flavor of controls held at 120C was maintained over time, while treatments held at

2C had decreased levels of overall flavor intensity. Off flavors increased over time for

sliced fruit compared to whole fruit controls. Acidity was maintained in whole fruit at

120C, but decreased in treatments held at 20C. Sweetness was maintained over time.

Sliced fruit and whole fruit stored at 20C had lower acceptability than whole fruit at

120C.

Other quality attributes

Soluble solids results for replication 3 were similar to results in replication 2. All

fruit maintained soluble solids (Table 10). Sensory results in Tables 9 and 10 concurred

with percent soluble solids results in that there was no difference in sweetness between

treatments.

All treatments basically maintained their pH over time, as indicated in Table 10.

There was a decrease in titratable acidity of sliced fruit, which agrees with replications 1

and 2, but sensory results did not indicate a change in acidity over time.

These fruit were initially softer compared to the "Florida 47" variety. Whole fruit

controls maintained firmness, while sliced samples decreased in firmness throughout

storage as indicated in Table 10. This agrees with sensory results shown in Tables 9.









For surface color of the slices, sliced fruit held at 20C had the least amount of red

color intensity over time, as indicated by Table 10. The a value changed from 16.1 to

13.5. Also, the hue, decreased over time. The hue of the sliced fruit changed from

approximately 36- 40.4. Controls stored at 20C maintained their red color intensity over

time. There a value was approximately 16.1 throughout storage, but their hue increased

from 39.1- 45.1, showing a loss of red color intensity, characteristic of chill injury.

Microbiological results

Sliced tomatoes experienced increases in both aerobic and yeast and mold plate

counts. Aerobic Colony Forming Units(CFU/g) increased over time from 10x 10cfu/g to

10x106 cfu/g by Day 10.Yeast and mold pate counts increased from 10x101 cfu/g to

10x103 cfu/g by Day 7. For most products, the level of microbes that constitutes spoilage

is approximately 1 x 107 microbes per gram of sample(Davis and Connor, 2001), usually

producing a visible color change of the product, or odors from the byproducts of the

microbes (Davis and Connor, 2001).The results indicate that the tomato slices were still

considered edible, but were on the verge of being spoiled.

Red-stage Tomatoes: Replication 3

Sensory results

Sensory results for replication 3 were similar to replications 1 and 2, as indicated

by Table 11. There was no development of red color intensity throughout storage for red-

stage "Mountain Spring" tomatoes (average hue=40). Sliced fruit showed signs of

increased watersoaking over time and compared to controls, as indicated by replications 1

and 2. Controls held at 120C held less fresh tomato aroma and decreased over time. There

were no differences between treatments during storage for off odors, but all sample














Table 4-9:The effects of treatment at each storage time on sensory attributes of sliced and whole light-red-stage "Mountain Spring"
tomatoes stored at 20C and 12C.


Red
Color
Treatment' Intensity


Water-
soaked
Appearance


9.8a2 4.3a
9.6a 4.2a
9.2a 3.9a


9.6a 2.9b
9.7 a 3.4ab
9.8a 4.5 a


7.0b 4.1a
8.6a 4.0a


Fresh
Tomato
Aroma


Off-
odors


Firmness Juiciness Mealiness


Overall
Flavor
Intensity


9.9a 2.2a 7.2a 8.6b 5.4a 8.3a
10.7a 2.1a 7.0a 10.4a 4.5a 8.5a
9.5a 2.4a 7.7a 9.4a 5.2a 8.7a
8.9a
9.7 a 2.5a 8.0a 8.7a 4.5ab
10.0 a 2.8a 8.3a 9.3a 3.8b 9.6a
9.0 a 2.9a 7.0a 9.1a 5.8a 8.3a
7.5b


9.5a 2.5ab 7.7ab 8.8a 5.5a
10.4a 1.7b 7.1b 9.6a 6.0a


Overall
Ripe
Tomato
Flavor


Off-
flavors


Overall
Acidity Sweetness Acceptability


2.6a 7.3a 6.0a
2.1a 6.4a 6.3a
2.9a 7.0a 5.6a


10.la 2.4a 7.0a 6.6a
10.3a 1.8a 8.1a 6.3a
9.1a 2.6a 7.0a 6.1a


7.6b
8.6ab 9.6a


2.4a 6.0a 6.0a
2.1a 7.1a 5.7a


2SLI 8.6a 3.9a


9.2a 3.0a 8.3a 9.2a 3.7b 9.6a


8.6ab 2.4a 6.7a 5.9a


6.6c 4.6ab
9.5a 3.9b
8.0b 5.7a


8.1b 4.1a 5.8b
9.4a 3.0b 6.0b


8.1a 8.7a
8.9a 4.5c 9.4a


7.9b 4.3a 8.7a 9.0a 7.3b 7.1b


3.7ab 6.4b 6.0a
2.8b 8.8a 5.7a
4.8a 6.6b 5.4a


Time Effect3 *


* *


ns *


* *


ns


'.Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C
2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect


Time
(d)


2W
0 12W
2SLI


2W
3 12W
2SLI


2W
6 12W


2W
10 12W
2SLI


8.2b
9.7a
7.8b


6.0b
8.4a


6.1b
9.0a










Table 4-10:The effects of treatment on other quality attributes of sliced and whole red-
stage "Florida 47" tomatoes stored at 20C and 12C
g citric
Time % soluble acid/100 Compression Hue (tan-1
Treatment' (d) solids pH mL Force (N) L *a (b/a))
12W 0 4.5a2 4.3a 0.35a 0.61a 43.6a 16.1a 37.0a
2W 0 4.5a 4.3a 0.35a 0.81a 45.9a 16.2a 39.4a
2SLI 0 4.5a 4.3a 0.35a 0.70a 45.9a 16.1a 36.1a

12W 3 4.6a 4.3a 0.35a 0.53a 44.5a 17.8a 39.8a
2W 3 4.5b 4.3a 0.35a 0.59a 45.6a 16.6b 38.2ab
2SLI 3 4.5b 4.3a 0.35a 0.59a 40.9b 17.6a 36.3b

12W 6 4.6a 4.4a 0.35b 0.37a 46.2a 17.9a 39.3b
2W 6 4.5b 4.3b 0.36ab 0.67a 47.2a 16.2b 45.5a
2SLI 6 4.5b 4.3b 0.4a 0.61a 44.9b 14.0b 42.lab

12W 10 4.6a 4.4a 0.37a 0.55a 42.9ab 18.5a 40.4b
2W 10 4.6a 4.3b 0.36a 0.45b 45.la 15.8b 45.la
2SLI 10 4.5a 4.3b 0.32b 0.35c 39.7b 13.5c 46.8a
Time effect3ns ns *
1Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced
fruit held at 20C
Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple
Range Test, 0.05)
3 indicates a significant storage effect at the 0.05 level. iin' indicates a non significant storage time
effect.


showed increased off odors over time. Sliced fruit and fruit at the holding temperature

were firmer than fruit held at 20C. Mealiness remained fairly constant over storage for all

treatments. Overall flavor intensity decreased for sliced fruit and fruit held at 120C. The

overall flavor intensity also decreased for fruit at the holding temperature. Off flavors

increased over time for all treatments. Sliced fruit, as well as fruit at the holding

temperature, had less acidity than fruit held at 20C. Sweetness was maintained throughout

storage. Sliced fruit and fruit at the holding temperature experienced a drop in their

acceptability over time and compared with fruit at the holding temperature.









Other quality attributes

All treatments maintained their percent soluble solids throughout storage (Table

12). This agrees with sensory data in Tables 11; panelists did not indicate a sweetness

change throughout storage.

All fruit maintained their pH and percent titratable acidity. Sensory data indicated a

loss in acidity of sliced tomatoes throughout storage as in replications 1 and 2. All fruit

maintained their firmness over time as indicated by Table 12. Whole fruit controls had a

slight increase in firmness over time, indicating possible variability within samples. Some

areas of fruit become more bruised than others, causing the sample slice to have many

different firmness measurements in its tissue.

Sliced fruit had decreased a value throughout storage, most likely resulting from

the development of water-soaked appearance, which lessens the intensity of red color.

Sensory results did not find a significant change in red color intensity.

Microbiological results

Sliced tomatoes experienced increases in both aerobic and yeast and mold pate

counts. Aerobic Colony forming units increased over time from 10x101 cfu/g to 10x104

cfu/g by Day 7.Yeast and mold plate counts increased from 10x101 cfu/g to 10x103 cfu/g

by Day 7. These results indicate that the tomatoes were still considered safe to consume,

but most likely were developing off-flavors and odors as a consequence of microbial

growth.













Table 4-11 :The effects of treatment at each storage time on sensory attributes of sliced and whole red-stage "Mountain Spring"
tomatoes stored at 20C and 12C.


Time
(d) Treament'
2W
0 12W
2SLI


2W
3 12W
2SLI

2W
7 12W
2SLI


Red
Color
Intensity
10.la
10.la
10.6a


10.la
9.9a
10.6a

9. la
9.7a
10.0a


Water-
soaked
Appearance
4.7a
4.6a
5.6a


3.7b
4.1b
5.8a

5.3b
6.0ab
7.0a


Fresh
Tomato
Aroma
8..9a
9.8a
10.2a


8.8a
8.9a
8.5a

8.1a
6.5b
7.7ab


Off-
odors
3.la
2.9a
2.3a

2.8a
2.7a
2.8a

4.1a
5.0a
4.3a


Overall
Flavor


Firmness
6.4a
8.2a
7.0a


7.5a
6.3b
4.5c

7.3a
5.4b
5.7ab


Juiciness
9.6a
9.3a
7.4b


9.9a
9.9a
8.9a

9.5a
7.7b
9.2a


Overall
Ripe
Tomato


Off-


Mealiness Intensity Flavor flavors Acidity
5.7a 8.4b 9.8a 3a 5.3a
4.5a 10.2a 10.la 3a 7.4a
5.8a 8.3b 9.3a 2.2a 6.4a


9.3a
8.7a
7.2b

9.0a
6.1c
7.6b


9.6a
9.3ab
8.3b

8.7a
6.6b
7.7ab


2.4a
2.0a
2.7a

3.9a
4.4a
4.1a


8.6a
8.3a
5.6b

7.4a
6.3ab
6.1b


Time Effect3 ns


* *


ns *


* *


Sweetness
6.8a
6.9a
6.8a


6.7a
6.5a
6.5a

5.5a
4.9a
5.7a


Overall
Acceptability
7.6a
9.5a
8.1a


8.2a
8.2a
6.0b

7.7a
6.6ab
5.8b


.Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C
2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect










Table 4-12: The effects of treatment on other quality attributes of sliced and whole red-
stage "Mountain Spring" tomatoes stored at 20C and 12C

g citric Hue
acid/100 (tan1
Treament' Time (d) Deg. Brix pH mL Force (N) L *a (b/a))
12W 0 4.6a2 4.39a 0.34a .46a 44.0a 19.9a 39.5a
2W 0 4.6a 4.39a 0.34a .49a 44.3a 22.0a 37.9a
2SLI 0 4.6a 4.39a 0.34a .47a 44.2a 20.0a 38.4a

12W 3 4.7a 4.38a 0.34b .88a 42.lab 21.7a 37.4ab
2W 3 4.6b 4.37a 0.41a .53b 44.6a 19.3b 39.1a
2SLI 3 4.6b 4.38a 0.34b .52b 38.6b 18.1b 36.0b

12W 7 4.7a 4.43a 0.34a .65a 43.3a 19.3a 38.1a
2W 7 4.6b 4.37b 0.34a .49a 42.9a 17.6b 39.6a
2SLI 7 4.6b 4.37b 0.34a .56ab 36.3b 14.8c 36.6b

Time
effect3 ns ns *
'Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced
fruit held at 20C
2Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple
Range Test, 0.05)
3 indicates a significant storage effect at the 0.05 level. nii' indicates a non significant storage time
effect.


Study 2

Light-red 1-MCP Treated Sliced Fruit vs. Control Fruit

Sensory results

Use of 1-MCP has shown to be effective in inhibiting ethylene production,

respiration, softening, and color change in fresh-cut apples (Watkins, 2002). On the

contrary, 1-MCP treated light-red-stage "Florida 47" tomatoes (MCP) did not experience

much change compared to control fruit (CONTROL), regarding most of the attributes and

quality parameters as indicated by Tables 13 and 14. MCP treated fruit exhibited less

firmness compared to control fruit around Day 7. Also, 1-MCP treated fruit had greater

overall flavor intensity compared to control samples by Day 7. Panelists did not detect

differences among control fruit and 1- MCP treated fruit for the remaining attributes.









In a study where modified atmosphere packaging (MAP) were used with Fresh-cut

tomato slices, it was shown that slices held in packages where there were low levels of

ethylene had more water-soaked appearance than slices stored in packages of with high

ethylene levels (Gil, 2002).

Other quality attributes

The soluble solids of 1- MCP treated light-red "Florida 47" fruit and control fruit

maintained their soluble solids over storage, as indicated in Table 14. This data agrees

with sensory results in Table 13. Panelists did not detect a significant difference between

treatments as well as throughout storage, as shown in Table 13.

The pH of both 1-MCP treated fruit and control slices was similar and was

maintained throughout time. This concurs with sensory results, which resulted in

treatments maintaining their acidity throughout time and not differing from each other

The titratable acidity of all fruit maintained at approximately 0.32 percent citric acid, as

shown in Table 14.

Both treated samples and controls experienced a loss of firmness over time as

shown by Table 14.

The "a" value decreased over time for both 1-MCP treated fruit as well as control

fruit from approximately 11-9, as indicated by Table 16. The hue maintained at

approximately 52-55. There was no difference over time or between treatments.

Red 1-MCP Treated Sliced Fruit vs. Control Fruit

Sensory results

Panelists detected differences in water-soaked appearance at Day 7 of storage.

Control fruit had less water-soaked appearance than 1-MCP treated fruit. Hong and Gross












Table 4-13: The effects of 1-MCP at each storage time on sensory attributes of sliced Light-red "Florida 47" tomatoes.
Overall
Red Water- Fresh Overall Ripe
Time Color soaked Tomato Off- Flavor Tomato Off- Overall
(d) Treament' Intensity Appearance Aroma odors Firmness Juiciness Mealiness Intensity Flavor flavors Acidity Sweetness Acceptability


MCP 8.4a2 4.5a
Control 8.9a 3.7a


MCP 7.5a 6.0a
Control 8.3a 6.0a


MCP 7.6a 4.0a
Control 7.la 5.4a


9.4a 1.9a 7.6a 7.3a 5.2a 7.0a
8.9a 2.2a 7.3a 7.2a 5.0a 6.6a


8.6a 3.0a 6.4a 7.3a 6.la 6.9a
8.1a 3.0a 7.1a 7.8a 6.2a 6.8a


7.7a 2.9a 8.8a 7.5a 3.8a 8.7a
7.0a 3.7a 7.0a 7.7a 4.3a 7.5b


2.1a 4.4a 5.5a
2.5a 4.8a 5.8a


2.6a 5.2a 6.0a
2.3a 4.9a 5.5a


3.0a 6.3a 5.6a
3.4a 4.9a 5.2a


Time Effect3* ns ns *
'.Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C
2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect


7.3a
7.5a


6.7a
6.7a


7.0a
5.3a


* *










Table 4-14: The effects of 1-MCP on other quality attributes of sliced light-red-stage
"Florida 47" tomatoes stored at 5C

Time %Soluble %Citric Compression Hue
Treatment' (d) Solids pH Acid Force (N) L *a (tan' (b/a))
MCP 0 4.5a2 4.3a 0.32a 0.97a 43.9a 11.0a 54.0a
CONTROL 0 4.5a 4.3a 0.32a 1.2a 44.9a 10.0a 55.3a

MCP 3 4.6a 4.3a 0.32a 0.85a 44.3b 13.3a 51.8a
CONTROL 3 4.5a 4.3a 0.32a 0.82a 47.3a 12.2a 51.6a

MCP 7 4.6a 4.3a 0.31a 0.85a 38.2a 10.1a 52.5a
CONTROL 7 4.6a 4.3a 0.32a 0.74a 40.6a 9.3a 56.6a

Time effect3 ns ns ns *
1Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced
fruit held at 20C
Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple
Range Test, 0.05)
3 indicates a significant storage effect at the 0.05 level. iin' indicates a non significant storage time
effect.


(2001) found that exposing fresh-cut tomatoes to high levels of ethylene reduced water-

soaked appearance, they also concluded that unlike whole fruit storage, post harvest

storage treatment with fresh-cut tomato should avoid ethylene reduction strategies (Hong

and Gross, 2002).

Red-stage slices had more water-soaked appearance than light-red-stage samples,

which is in agreement with Gil et al. (2002). They also hypothesized that the

development of translucence, or water-soaked appearance, was related to the low

temperature as well as the stage of development of the fruit. More mature fruit had higher

levels of water-soaked appearance (Gil et al. 2002).

Other quality attributes

The percent soluble solids for light-red-stage "Florida 47" sliced tomatoes treated

with 1 ppm 1-MCP and control slices remained consistent throughout storage (Table 16).









There were no treatment differences for soluble solids at any storage as well as between

treatments. This concurs with findings from Wills and Ku (2002).

The pH and percent titratable acidity were also consistent throughout storage as

indicated in Table Treatment effects, as well as storage effects, were negligible and

produced no differences between 1-MCP treated slices and control slices. MCP inhibited

loss of titratable acidity in comparison with control samples (Wills and Ku 2002), but

perhaps longer storage would have supported their findings.

There was a general trend in decrease of firmness during storage for both

treatments(Table 16). There was no difference between control fruit and 1-MCP treated

fruit. This concurred with sensory data, shown in Table 15, in that there were no

significant differences between treatments.

Over time, both treatments decreased in L value, or lightness of slices. This occurred

when the slices were becoming water-soaked. At 7 days, 1-MCP treated slices had lower

L values than control samples, as well as lower hue values. This did not concur with

sensory data. Although results were not significant for water-soaked appearance, this is

probably due to variability within treatment. There are some parts of the tomato,

primarily the bottom end, where water-soaked appearance is greater than other part of the

fruit (Hong and Gross 2000). Although slices were taken from the middle of the fruit, the

slices closer to the bottom end were more water-soaked. Also, within slices themselves,

there was variability in the degree of water-soaked appearance.

Study 3

Because 1-MCP applied directly to tomato slices was shown to be ineffective in

extending shelf life (Study 2), investigating the effects of 1-MCP on whole red-stage

tomato fruit, which is sliced after treatment was of interest. Red-stage tomatoes were












Table 4-15: The effects of 1-MCP at each storage time on sensory attributes of sliced red-stage "Florida 47" tomatoes.
Overall
Red Water- Fresh Overall Ripe
Time Color soaked Tomato Off- Flavor Tomato Off- Overall
(d) Treament' Intensity Appearance Aroma odors Firmness Juiciness Mealiness Intensity Flavor flavors Acidity Sweetness Acceptability
0 MCP 11.3a2 4.2a 9.2a 2.7a 5.8a 7.8a 4.2a 7.9a 8.6a 2.15a 4.7a 7.1a 8.0a


0 Control 10.6a 3.4a


8.9a 2.7a 6.0a 8.6a 3.9a 8. la


2.14a 3.8b


MCP 11.4a 3.5a
Control 10.7a 4.0a


7 MCP


10.la 7.2a


7 Control 9.2a 6. lb


8.1a 3.0a 7.3a
7.4a 3.4a 7.0a


7.5a 4.8a Z4
7.2a 4.6a Z


7.8a 5.2a 8.3a
6.7a 4.9a 7.7a


Z Z Z
Z Z Z


2.6a 4.9a 5.6a
2.7a 5.la 6.4a


Z Z Z
Z Z Z


Time Effect3* ns ns ns ns
'.Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C
2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect
4z-samples were unacceptable to taste


* *










Table 4-16: The effects of 1-MCP on other quality attributes of sliced red-stage "Florida
47" tomatoes stored at 5C

%Soluble g citric Compression Hue
Treatment' Time (d) Solids pH acid/100mLForce (N) L *a (tan' (b/a))
MCP 0 4.6a2 4.4a 0.32a 0.58 a 43.la 18.0a 43.6a
CONTROL 0 4.6a 4.4a 0.32a 0.66 a 42.7a 17.5a 43.3a

MCP 3 4.7a 4.4a 0.31a 0.48a 38.3a 15.7a 43.4a
CONTROL 3 4.7a 4.4a 0.31a 0.46a 40.2a 16.6a 44.2a

MCP 7 4.7a 4.4a 0.32a 0.45a 35.7b 15.la 44.2b
CONTROL 7 4.7a 4.4a 0.31a 0.57a 41.la 12.7b 49.1a

Time effect3 ns ns ns *
1Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced
fruit held at 20C
Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple
Range Test, 0.05)
3 indicates a significant storage effect at the 0.05 level. iin' indicates a non significant storage time
effect.

treated at 20C with Ippm 1-MCP for 24 hours. Tomatoes were then sliced and

maintained at 30C for 6 days. Sensory evaluation of treatment and control samples was

conducted at time 0, 2, and 6 days. Throughout storage, all samples had increases water-

soaked appearance and off-odors; both treatments had decreases in fresh tomato aroma

and overall ripe tomato flavor, as indicated by Table 17.

It was found that concentrations of 2 ppm were needed to extend shelf life of ripe

tomatoes (Blankenship and Dole 2003). A higher concentration may have been needed

for greater effectiveness of 1-MCP treatment. Control fruit had decreases in overall flavor

intensity during storage, while 1-MCP treated fruit maintained their overall flavor

intensity, which concurred with results from light-red slices in Study 2.

Control fruit had less water-soaked appearance than 1-MCP treated fruit on Day

6, but not enough to have significance. Although significance was not obtained, the

degree of water-soaked appearance concurs with the findings of Hong and Gross (1999)









The researchers treated slices with an ethylene synthesis inhibitor blocker (AVG) or had

ethylene absorbent pads in perforated packages in which the slices were stored. Slices

treated with AVG or placed in bags with ethylene absorbent packs had more water-

soaked appearance than control samples. So, the trend for an ethylene blocked sample (1-

MCP treated fruit) to have increases in water-soaked appearance is demonstrated by the

sensory results as shown in Table 17. Also, this strengthens the argument that water-

soaked appearance is not primarily caused from chilling injury. The expression of water-

soaked appearance might be an ethylene dependent phenomenon.

Hoeberichts et al. (2002) proved that ethylene perception is needed for the

expression of tomato ripening-related genes at the mature green, breaker, and orange

(pink) stages. They indicated that ethylene needs to be present throughout the ripening

process in order to ripening related physiological responses to occur (Hoeberichts et al.

2002). Hoeberichts et al. (2002) found that they could only delay the ripening of orange

tomatoes, which they could completely block the ripening of breaker tomatoes for 18

days. This implies that 1-MCP is more effective on less ripe fruit. The study did not

address the effects of 1-MCP on the red ripe stage of development.

It has been found that stage of ripeness had significant effects in the application of

1- MCP of bananas, pears, and apples (Blankenship and Dole 2003). Commercial lots of

bananas yielded mixed lots of fruits when 1-MCP had been applied. Also, the time from

harvest to treatment varied the effectiveness of the ethylene inhibitor. For most

commodities, treatment needed to be completed early after harvest. Perhaps treatment of

less mature whole fruit which is sliced after treatment would be more effective in

extending shelf life of fresh-cut tomatoes, but the initial quality of slices would be poor.














Table 4-17: The effects of 1-MCP on sensory attributes of whole red "Florida 47" tomatoes, which were sliced and stored at 5C after


treatment.
Red Water- Fresh
Color soaked Tomatc
Intensity Appearance Aroma


11.2a2 3.2b


Control 10.8a 4.4a


11.0a 9.8a


2 Control 10.7a 9.6a


10.5a 9.6a


6 Control 10.3a 7.6a


Off- Firmness Juiciness Mealiness Overall Overall
odors Flavor Ripe


11.5a 1.9a 7.4a
10.0b 2.8a 7.3a


Off-
flavors


Acidity Sweetness Overall
Acceptability


Intensity Tomato
Flavor
9.9a 5.9a 10.1a 10.6a 1.4a 8.8a 7.6a
8.9a 6.4a 9.9a 10.2a 2.2a 8.9a 6.3b


9.8a 2.4a 4.5a 9.6a 7.3a 8.7a

8.1b 3.4a 4.5a 9.1a 7.3a 8.4a


9.0a 3.2a 6.1a 8.9a 7.3a 9.1a
7.7b 4.7a 7.1a 8.9a 6.4a 8.4a


3.2a 8.3a 5.8a

3.0a 6.6b 5.4a


2.6a 8.7a 5.6a
2.la 7.4a 5.4a


Time Effect3 ns *ns ns***
.Treatments: 2W= whole fruit control held at 20C; 12 W= whole fruit control held at 120C; 2SLI= sliced fruit held at 20C
2 Means within a storage time followed by the same letter are not significantly different (Duncan's Multiple Range Test, 0.05).
Above sensory scores were rated on a 15 cm line scale anchored on one end by low and the other end by high.
3 indicates a significant storage time effect at the 0.05 level. "ns" indicates a non significant storage time effect


Time Treat
(d)


MCP


2 MCP


6 MCP


3














CHAPTER 5
CONCLUSION

The purpose of the first study was to evaluate whether ripeness stage affects the

sensory and quality characteristics of sliced and stored tomatoes when compared with

whole fruit controls held at chilling and non-chilling temperatures. The most affected

attributes to be considered when storing fresh-cut fruit are fresh tomato aroma, water-

soaked appearance, firmness and overall flavor intensity. Acidity, sweetness, overall ripe

tomato flavor generally were not important in determining the acceptability of sliced and

stored tomatoes. Mealiness, juiciness, and water-soaked appearance seemed to be good

indicators for chilling injury. The pH, percent titratable acidity, and percent soluble solids

overall did not change in the study; they did not have a major impact on the quality of

treatments over storage.

In all replications, both stages of tomatoes decreased in their fresh tomato aroma,

firmness, and overall flavor intensity; they also increased in their water-soaked

appearance. These sensory changes also resulted in lowered overall acceptability for the

fruit. The study also showed that in many respects, fresh-cut fruits respond to storage

similarly as whole tomato fruit held at 20C, and seemed to be chill injured as well as

senescing.

It was also demonstrated that light-red tomato fruit had a longer shelf life than red-

stage fruit. In light-red-stage tomatoes, most attributes were maintained throughout

storage until around Day 6 of storage. For red-stage tomatoes, changes began sooner,

around Day 3 of storage. Although light-red-stage tomatoes maintained their quality over









storage better than red-stage tomatoes, they had lower initial quality. The first study

supported the idea that maturity is an important quality factor of fresh-cut fruit. Also,

quality and sensory changes that occur to fresh-cut tomatoes during storage are a function

of chilling injury as well as senescence.

Sliced red and light-red-stage tomatoes were treated with 1-methylecyclopropene

for 24 hours at 5C and were stored for 7 days. The sensory and quality results

demonstrated that there was not much difference between control slices and slices treated

with 1-MCP. Light-red slices treated slices had more water-soaked appearance compared

to control fruit, and red treated slices had more water-soaked appearance than control

slices.

When red-stage whole tomatoes were treated with 1-MCP and then sliced and

stored, they had more fresh tomato aroma than control slices. This indicates that 1-MCP

might be more effective in delaying ripening in less ripe fruit than red ripe tomato fruit.

Overall, the application of 1-MCP on sliced and whole tomato fruit did not extend the

quality of fresh-cut tomatoes over storage.















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BIOGRAPHICAL SKETCH

Minna Leibovitz was born and raised in Miami, FL. She graduated from Miami

Sunset Senior High School in 1997. She received her Bachelor of Science degree from

the Food Science and Human Nutrition Department at the University of Florida in 2001.

Minna continued her education at the University of Florida and intends to receive her

Master of Science degree in food science in August 2003.