Group Title: Citrus Station mimeo report - Florida Citrus Experiment Station ; CES 67-10
Title: Possible effects of fruit handling practices on the quality of fruit for processing
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Permanent Link: http://ufdc.ufl.edu/UF00072446/00001
 Material Information
Title: Possible effects of fruit handling practices on the quality of fruit for processing
Series Title: Citrus Station mimeo report
Physical Description: 3, 3 leaves : ill. ; 28 cm.
Language: English
Creator: Vines, Herbert Max
Citrus Experiment Station (Lake Alfred, Fla.)
Florida Citrus Commission
Publisher: Citrus Experiment Station :
Florida Citrus Commission
Place of Publication: Lake Alfred FL
Publication Date: 1966
 Subjects
Subject: Fruit -- Handling -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: H.M. Vines.
General Note: Caption title.
General Note: "400-10/4/66-HMV."
 Record Information
Bibliographic ID: UF00072446
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 76248567

Full Text




Florida Citrus Commission and
Citrus Experiment Station CES 67-10
Lake Alfred, Florida 400-10/4/66-HMV


Possible Effects of Fruit Handling Practices on the Quality of
Fruit for Processing

H. M. Vines
Florida Citrus Commission
Lake Alfred, Florida


The expected life span of man living in the United States is estimated to
be about 70 years. This increase over the past and compared to some other
countries is due to advancements in science, medication, and easy living.
Citrus fruits also have a life span (they live and breathe, too) of from days
to months, depending on the care received in handling, temperature, and
medications applied.

It is unlikely that man's life span would be so great if he were loaded 10
layers deep in metal trucks, set in the hot direct sun, hauled over rough roads,
and dumped from 4 to 5 times his own height onto belts, as citrus fruits are
sometimes handled. Then why handle it in such a way as to cause premature aging?

Good handling practices are of extreme importance for the maintenance of
good quality of all citrus fruits. This includes not only oranges going into
fresh channels but also for the more than 80% which are processed. Damage to
fruit as a result of poor handling is often difficult or impossible to detect
by visual observations, nevertheless it causes a speeding of the aging process.

As fruits progress from green to mature to old age, they also progress in
vulnerability to infection by molds and decay. How often do you see a decaying
green fruit? There is a decrease in acidity as the fruit matures in addition
to deterioration of the cell structure. There is a loss of turgor of the fruit
which is due, in part, to a loss of water and to the above mentioned cell
deterioration. All of these processes are speeded up by improper handling.
Since the fruit cannot complain, we have used a method of evaluating or measur-
ing its welfare or state of health as affected by handling practices. As
stated earlier, fruit breathe using 02 and giving off C02 and heat. A measure
of C02 given off is a good indication of the rate of breathing and state of
health. This C02 comes from oxidation of the stored sugars and acids in the
fruit and represents the loss of these desirable constituents. These are lost,
never to be put into a can and, therefore, never reach the consumer.

Factors increasing this rate of loss are high temperatures, bruising,
pressure on the fruit, and fungal infection. An increase in C02 evolution is
noticeable two to three days before any infection can be seen with the unaided
eye. There is also an increase in production of ethylene by these infected
fruit. The ethylene evolved from a single infected fruit will cause an increase
in C02 evolution of nearby fruit and thereby promote additional infection and
aging.

Although possibly not practical at this time for processed fruit, lower
than normal 02 (not lower than 10%) levels in storage will reduce CO2 evolution
and retard chlorophyll disappearance in the peel and aging. Refrigeration or
reduced storage temperature will also extend the life span and reduce the
incidence of decay and its harmful ethylene production.











Some actual measurements or facts supporting the above statements are
offered. There is an increase of 800% in respiration rate (from 2 to 16 mg
C02/kg/hr) as the temperature of oranges and tangerines is increased from 50
to 860 F (Figure 1). Temperatures as high as 1300 F have been measured in
fruit left in direct sun at air temperatures of 860 F. Lemons which respire
slowly also showed an 800% increase (from 1 to 8 mg C02/kg/hr) with a change
in temperature from 50 to 860 F. Grapefruit, an intermediate respiring fruit,
showed a 600% increase in CO02 evolution with an increase in temperature from
500 to 860 F.

Within one day ethylene caused a 300% increase in C02 evolution over the
control fruit (Figure 2). Of course, ethylene for degreening purposes is
generally not used for processed fruit, but ethylene is given off by decaying
fruit particularly when infected with green mold. Dropping fruit a distance of
48 inches caused a 100% increase of C02 evaluation and a 24-inch drop caused a
50% increase (Figure 4). A not unreasonable pressure of 20 pounds for 30
seconds caused a 60% increase in CO02 evolution (Figure 3).

As mentioned earlier, oxygen levels lower than normal effectively lowered
the C02 evaluation as much as 70% below the control (Figure 5). Color
development, an indication of aging, is also retarded by low 02 storage. One
fruit, decaying because of green mold, even at a low 02 level will increase
CO2 and color development (probably because of the ethylene production).

The effect of different fungi on CO2 evolution has been measured. Percent-
age increase due to fungal infection were: Stem-end rot 300%, green mold 500%,
and blue mold 800% (Figure 6).

These increases in respiration rate of apparently intact fruit have
implications far beyond the losses in sugar and acid involved, although this
loss can be considerable (5 to 10 pounds of sugar per 400 box load per 24
hours).

A first obvious implication is that infection due to rough handling can be
growing vigorously in the fruit 2 to 3 days before it is externally apparent.
Thus, such fruit cannot be removed by the graders and may cause off-flavor in
the final product. A Penicillium mold growing in blue cheese (P. roquefortii
in this case) can make it more valuable, but the opposite effect happens with
citrus juice when diacetyl results from bacterial growth. The old story "A
rotten apple can spoil the barrel" can well be paraphrased to "an infected
orange can contaminate a juice run".

A less obvious effect is due to "anaerobiosis". A fruit can take in only
so much oxygen at any given temperature. When respiration raises oxidation
above the amount that this can satisfy, the fruit turns to anaerobic respiration
and produces not carbon dioxide and water but carbon dioxide and an objectionable
mixture of alcohols, aldehydes, and other odd tasting and odd smelling compounds.
Also, higher than normal (0.03%) CO2 levels in long term storage have caused
increased decay and possible off-flavor.


Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida.
400-10/4/66 HMV










A third consideration is the loss of aromatic volatiles responsible for
good quality, some of which have been identified while others are still unknown.

The quality of processed citrus products will be no better than that of
the fruit used and in this there is many a slip between the cup and the lip --
or the tree and the can.
















































Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida.
400-10/4/66 HMV















,Figure 1. The rate of respiration
of lemon grapefruit, orange,and
tangerine in relation to each other
and at six different storage
temperatures.


Figure 1.








,Figure 2. The respiration rate of
'Valencia' oranges at 60 F as
affected by 50 ppm of ethylene for
a 24-hour period. (Numbers in the
graph are respiration rate expressed
as mg CO2/kg/hr.)


450


400


350


300


250


200


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TIME- DAYS


Figure 2.


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Figure 3.









Figure 4. The respiration rate
of 'Valencia' oranges at 600 F
as affected by dropping 24 and 48
inches to a hard surface. (Numbers
in the graph are respiration rate
expressed as mg CO2/kg/hr.)


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Figure 3. The respiration rate
of 'Valencia' oranges at 60* F
as affected by mechanical pressure
applied for 30 seconds. (Numbers
in the graph are respiration rate
expressed as mg CO2/kg/hr.)


I 2 3 4 5 6
TIME-DAYS


Figure 4.


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Figure 5.


Figure 6. Relative increase of
the respiration rate of orange
flavedo infected with stem-end
rot, green mold, and blue mold.


UI RESPIRATION RATE OF
ORANGE FLAVEDO INFECTED
WITH DIFFERENT FUNGI


SPENICILLIUM
ITALICUM
(BUE MOLD)
0


PENICILLIUM
0 DIGITATUM
(GREEN MOLD)


PHOMOPSIS CITRI
0o (STEM-END ROT)



0 [ T CONTROL 40442
0 1 2 3 4
TIME- HOURS


Figure 6.


Figure 5. The respiration rate of
'Bearss' lemons at 600 F as
affected by subnormal oxygen levels.
(Numbers in the graph are respiration
rate expressed as mg C02/kg/hr.)




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