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University of Florida
Citrus Experiment Station
Lake Alfred, Florida
Thursday, October 16, 1969
8:00 A.M. Registration
9:00 A.M. WELCOME
Herman J. Reitz,
Horticulturist and Head
Citrus Experiment Station.
Edward A. Taylor
Florida Department of Citrus
Chairman: Warren Savant, Executive Vice President, Florida
Canners Association, Winter Haven.
9:15 A.M. HANDLING MECHANICALLY HARVESTED FRUIT AT THE PROCESSING
PLANT Glenn Coppock, Research Engineer III, Florida
Department of Citrus, Lake Alfred, and W. Grierson,
Horticulturist, University of Florida Citrus Experiment
Station, Lake Alfred.
Various mechanical harvesting concepts have been developed and
evaluated over the past 10 years. Many of them failed because they
were not practical or economically sound. Mass removal concepts which
depend on air or mechanical limb shakers have survived and several
promising harvesting systems developed to the prototype stage. In the
future, processing plants can expect to receive an increasing amount
of fruit harvested with these systems.
Limited experience in handling mechanically harvested fruit at
the plant has pointed out several problems which will need attention.
Mechanically harvested fruit has a high percentage of stems attached
which play havoc with belt conveyors, grading tables, and transfer
points. They pack up in the extractors presenting a greater cleanup
problem. A high content of leaves, sticks and sand is also present.
Most of the mechanical damage to fruit is in the form of splits and
punctures which cause high decay after a 3 day storage period. This
limits the permissible storage period before processing. Although
these problems need attention, they are not of such magnitude as to
hinder the acceptance of mechanical harvesting. Preharvest fungi-
cides and abscission agents now being developed may be a partial
9:30 A.M. JUICE COLOR AN IMPORTANT FACTOR IN EVALUATING QUALITY.
A.) THE PRESENT STATUS OF THE HUNTER CITRUS COLORIMETER IN
EVALUATION OF CITRUS JUICES R. L. Huggart, Chemist III,
Florida Department of Citrus, Lake Alfred, F. W. Wenzel,
Chemist, University of Florida Citrus Experiment Station,
Lake Alfred, and F. G. Martin, Associate Statistician,
University of Florida, Gainesville.
Color data obtained from the examination of 428 reconstituted
commercial samples of frozen concentrated orange juice (FCOJ),
collected from Florida processing plants during two citrus seasons
were statistically analyzed. Correlation coefficients and a multiple
regression equation were computed relating Hunterlab Citrus Colori-
meter (HCC) Citrus Red (CR) and Citrus Yellow (CY) values to average
visual color scores. The fit of the multiple regression equation was
quite good and explained 97.1% of the observed variation (%R). Using
this relationship a nomograph was constructed to estimate equivalent
color scores from colorimeter values. Simple correlation coefficients
were significant at the 99% level of confidence.
The range found between mean scores of 5 judges was 0.75 of a
visual score point. When 5 instruments were compared in 4 tests, the
ranges of CR means were found to be equivalent to 0.34, 0.20, 0.15,
and 0.08 of an OJ score point. The maximum range among citrus colori-
meters can be reduced to 0.20 or less of a score point by specific
Statistically significant numerical differences were found be-
tween instruments but the magnitude of the differences was of no
B.) METHODS FOR IMPROVING THE COLOR OF PROCESSED CITRUS
PRODUCTS S. V. Ting, Research Biochemist and C. D.
Atkins, Research Chemist, Florida Department of Citrus,
The color of orange juice was found to be the single most in-
fluential factor in determining consumer preference for the product.
A project was started at the Citrus Experiment Station in February,
1966 to investigate the feasibility of extracting carotenoid pigments
from orange peel and using them to enhance the color of orange juice
and orange juice products.
The process uses acetone as an agent to dehydrate the flavedo,
denature the protein of the plant material, and extract the carote-
noids. The extracted pigments in acetone are transferred to a small
volume of hexane, and the hexane together with low boiling materials
extracted from the flavedo is removed under high vacuum at 400C. Re-
cent trials using cold pressed orange oil to replace hexane were very
successful. At a pressure of 1 mm and a temperature of 40C nearly
all low boiling substances were removed leaving a highly colored folded
oil. After filtration to remove any precipitated substance, this
material can be added to concentrate directly by thorough mixing. For
single strength juice, the colored material is first added in a very
high concentration to a "stock" juice by vigorous stirring such as in
a Waring Blendor. The highly colored "stock" juice can then be
thoroughly mixed with other juice to a desirable color. This proce-
dure avoids the unnecessary incorporation of air into the product.
Comparisons of color of orange juice with added natural pigment
from 'Valencia' and 'Pineapple' flavedo were made on a Hunter Citrus
Colorimeter. Color comparisons were also made on juices with pigment
from 'Valencia' flavedo after oil extraction process and that from
intact flavedo. The amount of pigment added to the juice had a
linear relationship with the Hunter "a" values. The addition of 1 g
of the crude pigment to 8 liters of juice significantly increases the
visual color score of the juice.
Another process currently under investigation involves the
collection of material from whole oranges containing cloud, body,
color, oil, and essence. This material is obtained and can be added
to juice during the extraction process or stored for later use.
10:00 A.M. POUNDS SOLIDS CAN BE PREDICTED! Joe E. Mullin, Chief,
Florida Crop and Livestock Reporting Service, U.S.D.A.,
This presentation deals with the success of the Florida Crop and
Livestock Reporting Service in predicting the yield of frozen concen-
trated orange juice obtained by processors from the 1968-69 crop. In-
cluded in the speaker's address is a history of systematic tests of
fruit from sample groves which began at the request of the citrus in-
dustry in the fall of 1963. The purpose of a systematic testing
program is to refine orange forecasts by expressing them in terms of
pounds of solids. Experience to date suggests that this refinement
can be introduced in the near future.
This talk also will point out the fact that the maturity and
yield test results published by the Service revealed very early in
the season that the 1968-69 orange crop was unusually light in
terms of juice and pounds of solids.
10:30 A.M. WHERE DO WE STAND ON AN AUTOMATIC BRIX RECORDING DEVICE? -
James G. Blair, Research Engineer III, Florida Depart-
ment of Citrus, Lake Alfred.
Measurement of the Brix of single-strength orange juice has been
accomplished for many years using only a spindle hydrometer and a
thermometer. The temperature of the juice sample is obtained so that
a correction to the hydrometer reading can be made if necessary.
Statistical evaluation of hydrometer readings made by selected in-
dividuals under controlled conditions shows that determinations with-
in + 0.10 degrees Brix is possible only 68% of the time. This is one
of the reasons for the research effort on improving the method or
equipment for analyzing the juice.
Automatic equipment to read Brix within + 0.05 degrees 95% of the
time is under development. One machine using the refractive index
principle is currently being tested. It electronically converts the
optical measurement to a digital signal which can be transmitted to
any suitable readout mechanism. Another machine using a similar prin-
ciple is also being developed but is not presently available for test-
ing. Brix, as expressed in the citrus industry, means total soluble
solids, which is not the measurement derived from a refractometer.
Therefore, any results obtained by means of refractive indices must be
corrected for citric acid. An automatic titrator built several years
ago and recently improved to produce a digital output signal has worked
satisfactorily in measuring total acidity.
Measurements of specific gravity (Brix) through a balance system
is also under test. However, the device presently under test is not
capable of producing a digital output, although one is under develop-
All measuring elements of the pounds solids determination have
the capability of automatically producing a digital signal. Final
laboratory evaluation of the equipment and system needs to be com-
pleted so that field tests can be made.
10:45 A.M. B R E AK
11:00 A.M. PHYSICAL AND CHEMICAL CHARACTERISTICS OF COMMERCIAL FCOJ
PACKED DURING THE 1968-69 SEASON R. W. Wolford,
Research Chemist, and R. W. Barron, Chemist, Florida
Department of Citrus, Lake Alfred.
During the 1968-69 season, a total of 212 samples of commercial
FCOJ were examined for flavor and color. Flavor evaluations compiled
from the opinions of the taste panel members showed 91% of the samples
were rated good with the remainder of samples in the fair category.
Frequency distributions of the Hunterlab Citrus Colorimeter CR and CY
values showed the color for the reconstituted juices were slightly
poorer for the midseason samples compared with the same period for
1967-68, but about equal to the 1966-67 season juices. The late
season juices were better in color than for the two previous seasons.
Employing only numerical averages of flavor scores, samples were
divided into five arbitrary flavor groupings based on the CES 10-
point score sheet. A total of 45 samples from the 1968-69 season fell
into specific flavor grade categories of 5.8-6.1, 6.5, 7.0, 7.5, and
7.8-8.0. Physical and chemical analyses including volatile flavor
components were conducted. Correlation coefficients were developed
using these data for the several characteristics of the juices as
independent variables and flavor as the dependent variable. Similar
relationships using data for the 1967-68 seasons were developed. In
addition, data on the volatile flavor components for the three seasons
are introduced for possible correlation with flavor scores.
11:20 A.M. FLAVOR STUDIES BY ORGANOLEPTIC METHODS Paul J. Fellers,
Food Technologist, Florida Department of Citrus,
Every food plant and laboratory should have a strong quality
control section to monitor the quality of their own products and those
of their competitors. An integral part of any good quality control
program is a reliable and useful taste panel. It is imperative that
the flavor and perhaps certain other quality attributes in raw
materials, freshly prepared and stored products be checked in some
regular manner by either an expert taster or by an expert taste panel.
Taste panel evaluation is necessary in evaluating formulation or pro-
cess changes and in new product development. Panels can be conducted
to detect a difference or a preference, or to determine a grade or
quality level. Types of panels include the individual expert taster,
the small expert panel, semi-trained panels, and large untrained con-
sumer panels. Proper screening, training, and selection of panelists
for the expert panel is all important if that group is to be a useful
Taste panel procedures used at the Citrus Experiment Station
11:40 A.M. USE OF DIETHYLPYROCARBONATE IN CANNED CITRUS JUICES -
E. C. Hill, Research Bacteriologist, Florida Department
of Citrus, Lake Alfred.
Diethylpyrocarbonate (DEPC) has been used in Europe for several
years as a "cold sterilant" for beer, wine, carbonated drinks and
fruit based beverages. Under FDA Food additive order 121.1117 this
compound may be used in several beverages and drinks including up to
300 ppm in some fruit based beverages. DEPC decomposes within hours
to a few days, depending on storage temperature, to harmless ethyl
alcohol and carbon dioxide.
The compound is recommended for cold sterilization of beverages
with a cell count of less than 500 per ml. It would appear that DEPC
could be an ideal "top off" sterilization for cold filled chilled
citrus juices. Preliminary studies included three pilot plant runs
in which juices were packed in cans with and without DEPC at 2 differ-
ent concentrations with different levels of microbial contamination.
The canned juices were then stored at 800F. and examined periodically.
There was considerable can to can variation in microbial activity and
also variation in the numbers of organisms which would overwhelm a
given concentration of DEPC. In the packs in which the addition of
DEPC did not prevent spoilage it did in every case retard it. Two
brands of DEPC were used, Baycovin and Cold Pro. Taste tests after
five days indicated that the panel could not detect the presence of
these brands of DEPC when compared with the control juice.
11:50 A.M. A PROGRESS REPORT ON NEW ANALYTICAL PROCEDURES FOR EVALU-
ATING QUALITY M. D. Maraulia, Chemist II, Florida
Department of Citrus, Lake Alfred.
The production of new citrus products of excellent quality re-
quires the use of special analytical procedures. Some of these are
presently being used, while others are being perfected for future
study. Important tests applied in the new products program will be
12:15 P.M. L UN C H
NEW PRODUCTS SYMPOSIUM
Robert W. Rutledge, Executive Vice President, Florida
Citrus Mutual, Lakeland.
THE PRESENT STATUS OF ORANGE ESSENCE RECOVERY AND UTILL-
ZATION IN THE FLORIDA CITRUS INDUSTRY R. W. Wolford,
Research Chemist, Florida Department of Citrus, Lake
The present status of orange essence recovery in the Florida
Citrus Industry and some aspects of utilization of these essence
materials in present and future citrus juice products will be dis-
USE OF AN ALDEHYDE TEST FOR BLENDING ESSENCE AND CONCEN-
TRATE Don Petrus, Chemist III, and M. H. Dougherty,
Research Engineer II, Florida Department of Citrus,
The N-hydroxybenzenesulfonamide (HBS) test to determine the
aldehyde content of citrus essences, juices and processed products
is discussed. Changes and modifications of the original method,
which give more stability and reliability to the test, are pre-
sented. Data are given showing the differences obtained using the
modified and the normal methods and results are presented which show
the increase in accuracy and reliability when the modified method is
used for blending essences and FCOJ.
HIGH DENSITY CONCENTRATE WITH ESSENCE.
A.) INTRODUCTION John A. Attaway, Scientific Research
Director, Florida Department of Citrus, Lake Alfred.
HiD has 2 immediate economic advantages which will make it a
desirable product when present technical questions are satisfactorily
resolved. First, it increases the size of unit purchase as each can
contains a larger quantity of juice on a single strength basis.
Secondly, the use of essence to supply flavor should reduce the need
for cutback juice.
B.) OBSERVATIONS ON THE STABILITY OF HIGH DENSITY FROZEN
CONCENTRATED ORANGE JUICE E. C. Hill, Research
Bacteriologist, Florida Department of Citrus and R. W.
Olsen, Biochemist, University of Florida Citrus Experi-
ment Station, Lake Alfred.
Two high density orange concentrate packs of 570 Brix and 620
Brix were stored at 500, 40, 320 and -80F. The juices were examined
microbiologically and organoleptically initially and at weekly inter-
vals thereafter. There were great microbial and flavor variations from
can to can within those juices stored at the higher temperatures. At
50F. both concentrates were showing some spoilage by the fifth week
although the taste panel did not grade the reconstituted juice un-
acceptable until the sixth and seventh weeks. The concentrates stored
at 40F. were the only ones which showed a difference between the two
Brixes in taste and cell count. The 570 Brix concentrate showed some
spoilage before the ninth week and was graded unacceptable by the
taste panel by the twelfth week. The 62 Brix concentrate was graded
unacceptable by the fifteenth week but is still stable microbiologi-
cally after 22 weeks. The concentrates stored at 320F. were graded
unacceptable by the taste panel by the nineteenth week although micro-
bial plate count continued to decline and is considered stable after
22 weeks. The concentrates stored at -80F. showed a continued de-
crease in cell count and an unchanged flavor.
C.) POSSIBLE VISCOSITY PROBLEMS IN A HIGHER BRIX FCOJ -
A. H. Rouse, Chemist, University of Florida Citrus
Experiment Station and E. L. Moore, Research Chemist,
Florida Department of Citrus, Lake Alfred.
Three primary causes must be considered that could possibly lead
to viscosity problems arising from high density products. High vis-
cosity could result either from the effect of a combination of these
causes or from the effect of an individual cause. Water-soluble pectin
in a citrus juice, when concentrated, increases in viscosity. Water-
insoluble solids (pulp) primarily consists of juice sacs. Juice sacs
of Hamlin, Pineapple, and Valencia oranges contain and maintain approx-
imately 2% water-soluble pectin on dry-weight basis throughout the
growing cycle. At least 50% or more of the water-soluble pectin in
citrus juice is extracted from the juice sacs. Degrees Brix of a high
density concentrate, although sugar alone does not lend itself to
increased viscosity, does set up the following condition. As the de-
gree of concentration approaches 65% sugar in the presence of pectin
and acid, optimum conditions for setting a pectin gel are almost
reached. Combinations of pectin, pulp, and high Brix sugar solutions
show pseudoplastic properties that result in viscous liquids. Could
the consumer have a problem reconstituting a high density product if
the fold of frozen concentrated orange juice keeps increasing? Yes,
unless the viscosity of the high density product is kept similar to
the viscosity of the present product (44.80 Brix).
D.) A SUMMARY OF THE STATUS AND PROSPECTS FOR A HI-D WITH
ESSENCE PRODUCT R. W. Wolford, Research Chemist,
Florida Department of Citrus, Lake Alfred.
The present status and prospects for high density concentrate
with essence will be summarized in light of taste test results, the
industries capacilities in essence recovery, and some consideration
of the overall properties of such a newly designed consumer product.
2:50 P.M. B RE AK
3:00 P.M. GEL-COATED, READY-TO-SERVE GRAPEFRUIT HALVES -
W. Grierson, Horticulturist, and A. H. Rouse, Chemist,
University of Florida Citrus Experiment Station, E. L.
Moore, Research Chemist, Florida Department of Citrus,
and W. Wardowski, Assistant Horticulturist, Extension
Service, University of Florida Citrus Experiment Station,
Although recognized as one of the best flavored grapefruit, the
'Duncan' has limited fresh market acceptance because of its numerous
seeds. The seedy limitation may be overcome by the use of deseeded
grapefruit halves. Research in the Harvesting and Handling Section,
starting in 1966-67, showed that deseeded halves covered with shrink
film retained their flavor at 400F; but rind drying soon caused a
degenerated appearance. A separate project in Processing Research
produced citrus gels for salads and desserts. Reasonable shelf life
of prepared grapefruit halves was obtained at 40 F using these gels
to fill the center seed cavity and coat the cut surface. Moreover,
the gels could be sweetened with sugar, honey, or a dietetic sweet-
ener. A shipping test under unplanned severe conditions gave support
to the idea that grapefruit halves are marketable. The fast food
trade (that supplies prepared foods to restaurants and institutions)
is the natural outlet for this all-citrus product.
3:15 P.M. RECENT RESEARCH ON FROZEN CITRUS SECTIONS AND CHILLED
ORANGE RINGS Paul J. Fellers, Food Technologist,
Florida Department of Citrus, Lake Alfred.
Frozen citrus sections having acceptable flavor and texture
quality were successfully prepared using an E. I. DuPont de Nemours
and Company "Minimark", "Freon" freezer. Commercial Valencia orange
and Duncan grapefruit sections were treated as follows before freez-
ing: No treatment other than freezing, covered lightly with sucrose,
dipped in fresh orange (or grapefruit) juice to which was added 0.125
or 0.135% orange (or grapefruit) oil, or dipped in a 35% sucrose sirup
to which was added 0.125 to 0.135% orange (or grapefruit) oil. Pre-
liminary taste panel data have shown a decided preference for sucrose
and sucrose plus citrus oil treatments. Drip loss was found to be at
a minimum in the thawed sections. Texture was considered to be im-
proved over that found in sections frozen by normal I.Q.F. methods.
A section breakage problem was noted but it was thought machinery
and handling modifications would improve the situation. Also, residu-
al "Freon" gas adsorbed on the frozen sections sometimes caused plas-
tic bag bloating during the thawing process, a problem thought to be
solvable by allowing a longer time between freezing and packaging.
Since "Freon" freezing on a commercial scale has been estimated to
cost only about one cent/lb. of frozen product, the economics of the
operation appear advantageous.
Chilled Valencia orange rings have been successfully held at
400F. for up to one year with little serious loss in texture or
3:30 P.M. CITRUS SEED CLOUDING AGENT James W. Kesterson, Chemist,
and R. Hendrickson, Associate Chemist, University of
Florida Citrus Experiment Station and C. D. Atkins,
Florida Department of Citrus, Lake Alfred.
Clouding agents are used in the manufacture of oil flavor
emulsions to give turbidity to a final beverage drink. Two of the
most common agents used to imitate fresh fruit drinks are brominated
seed oils and glycerated rosins. This report shows that whole or
partially de-fatted citrus seed kernels, a natural food product, from
all varieties of citrus, such as: orange, grapefruit, tangerine,
lemon, lime, etc., are effective cloud producing agents for beverage
bases and food products.
3:45 P.M. A CITRUS JUICE ENERGY SUPPLEMENT FOR ATHLETES -
C. D. Atkins, Research Chemist, and John A. Attaway,
Scientific Research Director, Florida Department of
Citrus, Lake Alfred.
An isotonic type energy supplement is prepared by the addition of
small quantities of salts to single-strength or concentrated citrus
juices. The most acceptable orange juice ratios for this energy
supplement fall between 14 and 22. Where juices impart particular
sourness to the product, traces of phosphates may be included. Re-
duction of the pulp in the final product to below 3 percent produced
very satisfactory results where athletes were consuming considerable
quantities daily of the energy supplement. The quantity of salts in-
cluded in the citrus juices are the minimum amount for reasonable re-
moval by perspiration from the human body, calculated on normal ex-
ertion or physical exercise. Orange juice contains adequate quanti-
ties of minerals and vitamins for the general health, and the added
salts are entirely supplementary.
4:00 P.M. 1969-70 GOALS IN PROCESSING RESEARCH John A. Attaway,
Scientific Research Director, Florida Department of
Citrus, Lake Alfred.
The major effort this year is in new products. In addition to HiD
the staff is evaluating some entirely new product concepts including an
orange juice energy supplement for athletes, a form of high Brix con-
centrate which can be used as a starting material for a range of new
food products, blended citrus juices, gel-coated ready-to-serve grape-
fruit halves, orange nectar type products, and pickled citrus sections
and slices. Investigations are continuing on salad gels and sauces,
chilled and frozen grapefruit and orange sections and rings, and
certain specialty products such as a grapefruit juice, honey, and egg
drink. The evaluation of diethylpyrocarbonate in chilled juice will
be continued, and further research on the improvement of juice color
will be carried out.
In the by-product area, a new citrus seed clouding agent is pro-
In the flavor program the staff will continue to demonstrate
essence production equipment and techniques to interested processors,
as well as develop new chemical techniques for measurement and evalu-
ation of essences.
The chief goal of the Pounds-Solids program will continue to be
the evaluation of a satisfactory Brixometer.
These. Abstracts are for limited distribution only. Information
herein is not to be used for publication without permission.
Acknowledgment for helpful assistance is also made to Fred
Schopke, Ben Wood, Irene Pruner, Louise Cherry, Alice Barber, Betty
Willis, Mary Smith, Bud Kunz, Joe Collins, Fred Givens, Roy Albright,
Harold Walker, and to all other personnel of either the Citrus
Experiment Station or the Florida Department of Citrus who helped in
many and various ways.