Title Page
 Current activities of the Florida...
 Chemical characteristics and use...
 Citrus salad gels and jellied citrus...
 Frozen citrus sections and frozen...
 Current status of the Hunterlab...
 Fermentation products from citrus...
 Citrus experiment station pilot...
 Some characteristics of commercial...

Program for ... annual Citrus Processor's Meeting.
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Permanent Link: http://ufdc.ufl.edu/UF00066148/00004
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Title: Program for ... annual Citrus Processor's Meeting.
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Creation Date: 1968
Genre: serial   ( sobekcm )
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Table of Contents
    Title Page
        Title Page 1
        Title Page 2
    Current activities of the Florida citrus commission scientific research department
        Page A-1
        Page A-2
        Page A-3
        Page A-4
        Page A-5
        Page A-6
        Page A-7
    Chemical characteristics and use of orange essences
        Page B-1
        Page B-2
        Page B-3
        Page B-4
    Citrus salad gels and jellied citrus sauces
        Page C-1
        Page C-2
        Page C-3
    Frozen citrus sections and frozen and refrigerated orange slices
        Page D-1
        Page D-2
        Page D-3
        Page D-4
        Page D-5
        Page D-6
    Current status of the Hunterlab Citrus Colorimeter for measuring the color of frozen concentrated orange juice
        Page E-1
        Page E-2
        Page E-3
        Page E-4
        Page E-5
        Page E-6
        Page E-7
        Page E-8
    Fermentation products from citrus molasses
        Page F-1
        Page F-2
        Page F-3
        Page F-4
        Page F-5
    Citrus experiment station pilot plant dehydration facility and its utilization
        Page G-1
        Page G-2
        Page G-3
    Some characteristics of commercial frozen concentrated orange juices processed during the 1965-66, 1966-67, and 1967-68 citrus seasons
        Page H-1
        Page H-2
        Page H-3
        Page H-4
        Page H-5
        Page H-6
        Page H-7
        Page H-8
        Page H-9
Full Text



University of Florida
Citrus Experiment Station, Lake Alfred, Florida
Thursday, October 10, 1968

Morning Program 10:00 A.M. 12:15 P.M.

Introductory Remarks. H. J. Reitz, Horticulturist and Head, Florida Citrus
Experiment Station.

Scientific Research Program of the Florida Citrus Commission. J. A. Attaway,
Scientific Research Director, Florida Citrus Commission.

Chemical Characteristics and Use of Orange Essences. R. W. Wolford, C. D.
Atkins, M. H. Dougherty, M. A. Ismail, and D. R. Petrus, Florida Citrus

New Citrus Products

A. Citrus Salad Gels and Jellied Citrus Sauces. A. H. Rouse, Florida
Citrus Experiment Station and E. L. Moore, Florida Citrus Commission.
B. Frozen Citrus Sections and Frozen and Refrigerated Orange Slices.
P. J. Fellers, Florida Citrus Commission.

Afternoon Program 1:30 P.M. 3:30 P.M.

Current Status of the Hunterlab Citrus Colorimeter for Measuring the Color of
Frozen Concentrated Orange Juice. F. W. Wenzel, Florida Citrus Experiment
Station, R. L. Huggart and R. W. Barron, Florida Citrus Commission.

You and Agricultural Research. J. W. Sites, Dean for Research, Florida
Agricultural Experiment Stations, University of Florida, Gainesville,

Fermentation Products from Citrus Molasses. S. K. Long, Florida Citrus
Experiment Station.

Citrus Experiment Station Dehydration Facility and Its Utilization.
R. Hendrickson and J. W. Kesterson. Florida Citrus Experiment Station.


University of Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida
October 10, 1968

Research Reports

The summaries and tables of data in these reports were prepared and
assembled so that this information would be available to the Florida citrus
processors for use during the coming season. In this manner the results of
research investigations are released to processors promptly and without the
long delay entailed in writing, editing, and reviewing that is necessary for
final publication.

In addition to the papers presented at this meeting, the following
report concerning citrus processing is also attached.

(1) Some Characteristics of Commercial Frozen Concentrated Orange
Juices Processed during the 1965-66, 1966-67, and 1967-68 Citrus
Seasons. Citrus Experiment Station Report CES 69-6G.



Thanks are extended to Dr. J. A. Attaway for his review of the "Scientific
Research Program of the Florida Citrus Commission". Dr. Attaway was appointed
Scientific Research Director for the Florida Citrus Commission on September 1,
following the retirement on that date of Dr. L. G. MacDowell whose accomplish-
ments and service to the Citrus Industry and the Florida Citrus Commission ex-
tended over a period of 26 years.

The presentation of a large number of slides together with his discussion
of "You and Agricultural Research" by Dr. J. W. Sites is appreciated. Dr. Sites
is Dean for Research, Institute of Food and Agricultural Sciences, University of
Florida, Gainesville, Florida.

Data and information in these reports were obtained and assembled through
the cooperation of personnel on the staffs of both the University of Florida,
Citrus Experiment Station, under the direction of Dr. Herman J. Reitz, and the
Florida Citrus Commission, under the direction of Dr. L. G. MacDowell and/or
Dr. John A. Attaway.

Acknowledgment for helpful assistance given is also made to Fred Schopke,
Irene Pruner, Louise Cherry, Alice Barber, Betty Willis, Carrie Mike, Bud Kunz,
and to all other personnel of either the Citrus Experiment Station or the
Florida Citrus Commission who helped in many and various ways.


John A. Attawayl'2
Florida Citrus Commission
Lake Alfred, Florida

During Citrus Processor's Meetings over the past 19 years most of you have
become aware of the large Citrus Commission research effort in the area of pro-
cessed products, particularly that devoted to the use of citrus juices. However,
you may not be aware that in recent years, as the needs of the industry broad-
ened, the scope of the FCC program has likewise broadened to meet those needs.
Consequently, we are no longer just a fruit juice research group. Today's
research involves several major areas including mechanical harvesting and
abscission, new products, flavor and color enhancement of processed juices,
pounds-solids, control of decay in fresh fruit, control of grapefruit acidity,
and cooperative product testing with the FCC market research department. The
majority of this work is done in cooperation with the University of Florida
Citrus Experiment Station, but we also have a cooperative program with the
U.S.D.A. on foam-mat powders.

Since you have already been exposed to many aspects of the work in pro-
cessing, I will first talk about what we are doing in other related areas. For
example, one of our highest priority projects is that devoted to mechanical
harvesting and abscission. The term mechanical harvesting speaks for itself.
Abscission, for those unfamiliar with the term, as applied to our research
effort, involves attempts to promote the loosening or dropping of the fruit
through chemical means. Glenn Coppock is in charge of mechanical harvesting
research and development, while Bill Wilson is responsible for research on
abscission. Naturally they work together very closely.

The reasons for our expanded interest in this area is, of course, industry
need. Harvesting the citrus crop is probably one of the biggest problems facing
the industry today. The industry paid over 100 million dollars to harvest the
1966-67 crop with 75% of this going for labor. Separation of the fruit from the
tree and placing it into a suitable position on the ground is the big bottleneck
to increased efficiency, particularly in the older groves where the size and
shape of trees is an impediment to harvesting. This operation is performed
almost entirely by hand labor at the present time, and cost is not the only
factor as it is becoming increasingly difficult to find workers willing to
carry out this somewhat tedious job.

The potential for savings by improved harvesting methods is tremendous. A
reduction in harvesting cost of one cent per box in the 1966-67 season would
have reflected an industry saving of approximately two million dollars. In an
effort to gain some of this potential saving, the Citrus Commission has a re-
search project in cooperation with the University of Florida and the United
States Department of Agriculture to study ways of improving the harvesting
operation. Studies on this project have shown picking aids, such as pickers'
platforms and fruit-lowering chutes, to be unsuccessful primarily because they
do not speed up the pickers' picking rate enough to justify the extra equip-
ment needed.

Scientific Research Director.

Presented at Nineteenth Annual Citrus Processors' Meeting, Citrus
Experiment Station, Lake Alfred, Florida.

Consequently, present efforts are being directed toward the development
and evaluation of complete mechanical harvesting systems. One system employs
limb shakers mounted on two catching frames, one for each side of the tree.
In operation, the catching frames are pulled into position on opposite sides
of a tree and extended until they meet to form a seal around the trunk. The
shaker detaches the fruit by shaking individual limbs. The fruit drops onto
the surface of the catching frames where it is collected and stored in a bin.
When the bin is full, it is emptied into a conventional high-lift grove truck
which transports the fruit to a trailer located at the roadside. This system
has been found economical under certain grove conditions.

Another system is similar except the fruit is detached by an air-blast
foliage shaker. An oscillating blast of air directed toward the tree shakes
the foliage, causing the fruit to snap off. As in the mechanical tree-shaker
system, catching frames are provided to handle the fruit. The big advantage
of this air-blast shaker is that it can operate continuously without having
to stop at individual trees, as is the case with the mechanical shaker.

A third system employs either a limb shaker, air-blast shaker, or in the
'Valencia' variety, hand pickers, to detach the fruit. In all cases, ground
cloths or windrowing machines will be used to collect and window the fruit in
the middles. High-volume fruit pick-up machines are under development which
will pick up the fruit from the window and load it onto a grove truck. The
machine developed by Continental Moss-Gordin can pick up fruit at rate of 5
boxes per minute. Plans are underway to test prototypes of these systems under
commercial conditions during the coming season.

Shaker-type harvesters show the greatest promise for early and midseason
citrus; however, research is being conducted on a spindle-type harvester for
'Valencia' oranges. In the spindle harvester, the fruit is detached by being
caught between rotating spindles. It is hoped that a spindle can be developed
which will select the ripe fruit and leave the smaller fruit of the next year's
crop, which is on the tree at harvest time.

Although much of the attention is focused at the Citrus Experiment Station,
cooperating growers and machinery manufacturers are also a very essential part
of the mechanical harvesting program.

One major problem encountered in mechanical harvesting is that of obtain-
ing adequate fruit removal as citrus fruit are usually firmly attached to the
stem. As a consequence, plant physiologists were enlisted to try to reduce
this bonding force so that the various mechanical harvesting devices could
work more effectively. This is the basis of the abscission phase of the

Until recently, practically all abscission research with fruits involved
trying to set fruit or keep it from falling off before it got ripe. Purposely
loosening fruit for harvesting is a very new development.

One of the biggest problems with abscission is removing the fruit without
removing the leaves. Apples and pears do fine in winter with no leaves, but
oranges of course do not, and since the leaves and fruit have the same sep-
aration mechanism it is difficult to get one without the other.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-JAA

Bill Wilson has attempted to solve the abscission problem by spraying whole
trees in the conventional manner. However, some unique methods have also been
tried. For example, ethylene gas put under a tent works very well if the tent
is left over the tree for several hours. However, the work involved in tenting
up a whole grove one tree at a time would be prohibitive so Bill tried putting
the gas into the soil with a tube. The fruit came off fine, but the tree went to
its happy hunting ground. The operation was a success but the patient died!

California has had its troubles in this regard also. A bright engineer
claimed electricity would cause fruit to fall off trees. The results of his
experiments got world wide publicity, but unfortunately, no one could ever
duplicate these results. They did manage to kill some trees and it is my
understanding that this approach has been dropped.

Abscission is a difficult problem, but progress is being made. Ascorbic
acid or vitamin C, as it is more commonly called, has been found to be very
effective in loosening fruit, but unfortunately it costs too much. Bill is
looking at several cheaper chemicals and is mildly optimistic about a new
coded acid now under test. Nearly 1000 compounds have been field tested or
otherwise screened in the last two years, and continued screening is in pro-
gress. We are also stressing a basic abscission program aimed at answering
Why, so that perhaps we can stimulate our field research to show us How.
Mohamed Ismail, Joe Hawarah, and myself are carrying the load in this area.

Another project which you do not normally encounter involves the Commission's
work on decay control in fresh fruit. This effort is spearheaded by Eldon Brown,
who is pioneering in the area of preharvest fungicides, and Andy McCornack, who
is evaluating new post-harvest fungicides.

Detailed studies on postharvest decay fungi are being conducted to learn
when these fungi infect citrus fruit and how this infection is influenced by
weather, how entry is gained into the fruit, and how these fungi cause decay
once entry occurs. We are also interested in how these fungi exist in the
absence of fruit. Some of the decay fungi have been found to survive in dead-
wood on the tree while others grow in debris in the soil. By knowing how these
fungi live and what conditions are necessary for their growth, we hope to find
a way to improve our present methods of controlling post-harvest decay. Al-
ready, studies with experimental materials have led to the possibility of
applying fungicides in the grove previous to harvest rather than during the
postharvest period.

Similar studies are being pursued on peel injuries. These are blemishes
on the fruit caused by a sickness of the tree rather than by infection of
fungi. In certain years, citrus fruit from some groves tend to have more
peel injuries than in other years. This seems to be due to nutritional de-
ficiences and/or abrupt changes in water availability. By knowing the nutri-
tional elements or water relations causing such peel injuries, control may be
obtained by fertilizer application and/or irrigation.

Decay of Florida citrus fruit is a serious economic problem, particularly
in seasons when rainfall is high. It is caused by handling methods as well as
natural infections which occur when the fruit is still on the tree. Mold
enters fruit only through a break in the peel. Plugs, clipper cuts, scratches,
bruising and excessive brushing are examples of injuries which provide points
for mold entry. Fully-mature seedless grapefruit are subject to blossom-end
clearing. This type of bruising is found in the coastal areas of the State,
particularly the Indian River district.
Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-JAA

Stem-end rot is caused by infection in the fruit before picking. Break-
down around the stem-end of the fruit, usually of a brownish color, character-
izes this problem. Degreening with ethylene increases decay, especially when
high humidity is not maintained during the degreening period. Stem-end rind
breakdown is usually caused by a delay in handling between picking and packing,
especially when the relative humidity is low or when the fruit is improperly
degreened. Fruit subjected to low humidity tend to become soft and lose their
fresh appearance. An increase in decay results.

Two fungicides, Dowicide A and diphenyl (biphenyl), are approved by the
U. S. Food and Drug Administration for use on fresh citrus fruit. Experimental
fungicides are tested as a part of the regular experimental program to find
better fungicides for controlling citrus fruit decay.

Another interesting problem in the fresh fruit area involves the reduction
of grapefruit acidity. This was first studied by H. M. Vines, who is no longer
with the Commission, and is now being pursued by B. S. Buslig and myself. We
are attacking this problem from both the basic and applied angles. From the
basic standpoint we have isolated and studied several of the Kreb's Cycle en-
symes of grapefruit including the citrate condensing enzyme which catalyzes the
final step in the formation of citric acid. The applied approach has involved
both laboratory and field testing of enzyme inhibitors and oxidative phosphory-
lation uncouplers. Although field tests were only started this past season we
have found 2 compounds which seem to reduce acidity in a manner similar to lead
arsenate. However, much work remains to be done.

As representatives of the processing industry you are already familiar
with the Pound-Solids Project which was instituted in 1961. The objectives of
this program were to improve the methods and equipment used for the collection
of samples, the extraction of juice, and the measurement of Brix. In the last
8 years, considerable progress has been made in defining pound-solids, and de-
termining how it is affected by the variables involved, including fruit,
machinery, and man. A new sampler was put into operation 2 years ago, and a
modified extractor was put into operation last year.

The sampler is mounted in the receiving system of the plant and selects
an unbiased sample of fruit within an overall weight tolerance of + 5 pounds,
regardless of the size of the load or the rate of unloading. The State Test
House extractor has a repeatable accuracy of juice extraction and the
potential of obtaining a satisfactory juice yield from all varieties and sizes
of fruit. Research work is continuing toward eliminating the problem of juice
extraction from the Hamlin variety.

Considerable improvement in uniformity of pound-solids results is now ex-
perienced since all plants must use the same type test room equipment.

Limited research on automatically measuring the Brix of the juice sample
has been conducted and may be expanded in the future. Several devices have
been tested. One company has spent more than $100,000 on the development of a
unit that uses the refractive index principle for measuring Brix. This machine
requires an operator to introduce the sample, but from there on, everything is
automatic including the printing of the Brix reading.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-JAA

An automatic titrator should be used to correct the refractive index
reading for acid prior to print-out. Some research has been done on a device
of this nature and it is our belief that such an operation is quite feasible.

On even more familiar ground to you is the area of new products. The most
promising of these will be discussed in detail later in this program, or in the
U.S.D.A. program tomorrow in Winter Haven when Dr. Veldhuis and Dr. Berry will
bring you up-to-date on new developments in the cooperative program between the
U.S.D.A. and the Citrus Commission on foam-mat powder. Most of you are probably
aware that they are compressing the powder into tablet form and that it looks
very good.

Among our other new product possibilities are citrus salad gels and jellied
citrus sauces which will be discussed in detail by Al Rouse and Ed Moore later
in this morning's program. These are very tasty products which are attractive
in appearance. Natural citrus flavors are added to them for flavor enhancement.

Broken sections from sectionizing plants can be utilized in the preparation
of salad gels, and they could become a significant outlet for grapefruit and
oranges when there is an over supply of citrus.

Jellied sauces, like the salad gels, can be made either as hot processed
or chilled type products. These would be made from pulpy grapefruit and orange
juices. The jellied orange sauce would be similar to the jellied cranberry
sauce now on the market. A mint flavored grapefruit sauce could be served with
a variety of meat dishes.

Other new products which you will hear more about during this morning's
program are the frozen citrus sections and frozen and chilled orange slices
which Paul Fellers is developing.

Individually frozen citrus sections make an attractive product which
should enjoy good consumer acceptance both in the home and in the institutional
market. Flavor and texture problems have been associated with frozen grapefruit
sections, but it is thought that use of good quality fruit, a light sugar cover-
ing, and quick freezing results in an acceptable product.

Orange slices or rings are prepared by coring the lye-peeled fruit along
the stem-end to stylar-end axis, then cutting at right angles to that axis to
form the slices. They have been prepared as both frozen and chilled products.
For the frozen product, it has been found that a light sugar coating is pre-
ferred over slices having no treatment other than freezing. Chilled or re-
frigerated slices packed in glass have been found to maintain good orange
flavor and texture after several months of refrigerated storage. The covering
sirup used in this product contains enough sucrose and sodium benzoate to give
about 120 Brix sucrose and 0.05% sodium benzoate in the jar contents at equilib-
rium. Incorporation of citrus oils in small amounts has been found, in general,
to enhance the flavor quality of all these products, especially in the glass
pack where it is a simple matter to add orange oil to the covering sirup.

Another area of considerable interest to this group is concentrate improve-
ment. In this regard you've heard a lot about flavor research and essence re-
covery during the past several years. As a consequence of the cost-price
squeeze and attempts to attain maximum juice yields the industry became con-
cerned about flavor. The Commission responded with a research program, in
cooperation with the industry, which contributed much to the development of
essence recovery. This is all past history for you having been a topic in

each of the past 9 Processors's Meetings, and since Dick Wolford is next on the
program with presentation No. 10 there is no need for me to go into great
detail. In summary, our research and development program in essence recovery
resulted in the designing of a multi-stage recovery system by C. D. Atkins and
Dick Wolford, which was operated at the Citrus Experiment Station during the
1964-65 and 1965-66 seasons. Under cooperative agreement the recovery system
was then transferred to Lykes 7L Pasco Packing Company, Dade City for testing
in commercial operation. As a result of the commercial testing and the quality
of the recovered orange essences, a commercial essence system was designed,
employing the basic concepts of the FCC-CES system, and placed in operation by
Lykes-Pasco during the 1966-67 season. Late in the 1967-68 season the multi-
stage system was transferred, through cooperative agreement, to Winter Garden
Citrus Products Cooperative, Winter Garden for evaluation and testing and will
be in full operation this season.

Another aspect of concentrate improvement is color enhancement. We aren't
as far along with this as we are with essence. However, it is progressing.
This program began as a result of several consumer surveys which confirmed
what we already knew, namely that color is one of the most important factors
influencing the consumer's opinion about the quality of orange juice.

Lack of color is quite a problem with early oranges such as 'Hamlins'.
Even when there is enough cold weather to color up the peel, the juice is
still light yellow, and the nice colored peel vanishes into cattle feed. The
low-colored juice of early oranges could be improved by the use of synthetic
coal-tar dyes such as used in synthetic drinks, but state law prohibits this.
However, the color of the peel is a natural part of the orange, just like the
oil used for flavor fortification, and could be used to boost juice color if a
practical process for transferring the pigments from peel to juice could be
found. Jerry Ting of the Commission staff has been working on this problem for
the past 2 years and has developed a process for extracting the peel, concen-
trating the pigments, and adding the pigments back to the products. From the
peel of one box of good colored 'Pineapple' oranges he has been able to extract
sufficient color concentrate to significantly improve the color of 15 gallons
of juice. It is difficult to estimate the exact cost of this procedure, but
it would probably be acceptable in cost where a higher quality concentrate is

A last phase of the Scientific Research Department's work involves coop-
eration with the Commission's Market Research and Development Department under
Mr. Douglas R. Hoffer, which requires packs of numerous citrus juice products
to be tested at the consumer level. This has given us a chance to cooperate
with the industry quality advisory groups to pool ideas for improving all
citrus juice products, and come up with detailed programs for improvements in
preparation and packaging of those products.

Packs prepared for consumer testing have included evaluation of single-
strength canned juices and numerous concentrated products including FCOJ.
Canned juices prepared from packing house eliminations and grove run fruit
were packed at various levels of natural Brix concentrations varying from
straight single-strength to those fortified by slight concentration or the
addition of concentrate, and also those with the addition of sugar. This effort
to improve in as far as possible the quality of early and early-midseason canned
juices actually proved quite interesting to the industry groups before consumer
testing was carried out. Packs of concentrate containing non-caloric sweeteners,
and packs of high density orange concentrates with additional essence added to
enhance consumer acceptance, were prepared and the consumer testing was con-
ducted by the Market Research and Development Department throughout the United

Processing and packaging such packs for the industry at the Citrus Experi-
ment Station, or in the industry plants, is an important function of the Florida
Citrus Commission Scientific Research Department.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-JAA

Florida Citrus Commission and
Citrus Experiment Station CES 69-6A
Lake Alfred, Florida. 400-10/10/68-RWW

Chemical Characteristics and Use of Orange Essences

R. W. Wolford, C. D. Atkins, M. H. Dougherty,
M. A. Ismail and D. R. Petrus

Florida Citrus Commission
Lake Alfred, Florida

During the 1967-68 season a considerable volume of orange essence was pro-
duced in the Florida Citrus Industry. At least seven processing plants in
various stages of essence production accounted for approximately 1,500,000
gallons of the recovered flavor material. This amount of essence could provide
a major portion of the natural flavor necessary for as much as 40 to 50 million
gallons of 450 Brix orange concentrate. The 1968-69 season projections indi-
cate further increase in volume of recovered orange essences.

In view of present production capabilities and future projections on in-
creasing volumes of orange essences in the industry, consideration should be
given to some of the changes in technology brought about by this processing
operation. A few citrus processing plants having had from 1 to 8 years experi-
ence in this area of processing have done much in pioneering the commercial
developments in essence recovery, as well as obtaining solutions to practical
problems in the logistics and use of this flavor material. Much of the research
and development accomplishments have paralleled commercial development. Research
into the chemistry of essences has generally provided answers to technical
problems, thus facilitating their practical solutions.

The chemical characteristics of orange juices and their recovered essences
have been the subject of study in this laboratory for several years. Previous
reports to the industry and at the Annual Citrus Processors' Meetings, as well
as numerous publications have dealt with the results of these research efforts.
Active research concerning the chemical relationships, both qualitative and
quantitative, in orange essences are still of major consideration. Certainly,
from a practical standpoint a real need exists to determine the specific con-
centration of recovered essences to facilitate their addition to FCOJ and other
orange juice products. Further, the assessment of orange essences for aroma
and flavor quality is essential to predicting their value in enhancing the
flavor quality of these products. Research has shown that orange juice is
comprised of an extremely complex and delicately proportioned mixture of many
chemical compounds which contribute to its aroma and flavor. Thereby, orange
essence should contain the intrinsic flavor characteristics of the juice from
which it is obtained.

Seldom in the past has the industry been concerned with production, quality
control, storage and use of a water-base material such as orange or other citrus
juice essences. Ideologically, if aqueous orange essences were of constant chemi-
cal composition, both qualitatively and quantitatively, and possessed a consistent
flavoring potential, its addition to FCOJ, for example, could be made on a pre-
determined basis as a diluent and require only the present testing procedures to
comply with standards of identity. Under these conditions, FCOJ of consistent
high quality and improved flavor acceptance would be the rule instead of possibly
the exception. Unfortunately, the citrus industry is not endowed with a consist-
ent raw material for use in processing. Not only are seasonal variations en-
countered but those variations due to variety, rootstock, horticultural practices,

and differences between groves in one area or widely separated geographical
areas are experienced. However, much of the variability can be minimized by
blending fruit, juices and concentrates to achieve the desired physical and
chemical properties in the final product. This is true for percent solids,
solids/acid ratio, pulp contents and color, to name a few. Essences recovered
from freshly extracted orange juices or clean essence vapors from an evap-
orator, likewise, vary in volatile flavor contents as a result of variations in
the juices due to varietal differences, maturity, and physical conditions of the

Essence recovery systems now in commercial operation, when operated prop-
erly using a good source of essence vapor, are generally similar in affecting
a reasonably consistent qualitative chemical composition in orange essences.
However, the quantitative chemical composition of orange essences tends to vary
with the method or type of essence recovery system being used. Within any one
type of recovery system differences in the quantitative composition are sub-
stantially minimized.

.Paralleling the research and development efforts in recovery and storage
of orange essences, a continuing major portion of our research has been con-
cerned with the development of methods for quality control testing of essences.
This has consisted of a two pronged approach, one to satisfy the immediate need
for methods of assessing flavor quality and the other to provide a method for
determining concentration of essences to be used quantitatively in their addition
to FCOJ with some predictability toward flavor quality in the final product.

Some of the applicable methods for assessing flavor quality of recovered
essences as related to fresh juice have been the Chemical Oxidation Demand (COD)
test employed as a measure of volatile water-soluble compounds as reported by
Dougherty (1), and the methods of Attaway, et al. (2) for determination of
oxygenated terpenes of the general formula C10H180, saturated aldehydes as
octanal, and unsaturated aldehydes as citral. Results obtained using these
methods were reported by Wolford, et al. (3), and Attaway, et al. (4) at the
1967 Citrus Processors' Meeting. More recently a method for determining total
aldehydes in orange essences, developed by Ismail, et al. (5) has been employed
extensively in research to determine its applicability in quality control to
meet the needs outlined above.

The N-hydroxybenzenesulfonamide (HBS) test for total aldehydes has provided
good sensitivity of detection over a wide range of aldehyde values for orange
essences, orange juices, and reconstituted FCOJ. The method considered for
adoption is conducted as follows: to a 10 ml. test solution 1 ml. of 0.5% HBS in
95% ethanol and 1 ml. of IN KOH are added and the mixture allowed to stand for 10
minutes to allow time for reaction between the nitrosyl radical and the aldehyde
group. An inner color complex is formed upon the addition of 1 ml. 1% FeCl3 -
2N HC1 and the solution is allowed to stand for 15 minutes. The optical density
(O.D.) of the solution is read at 525 mnu using a Fisher Electrophotometer II and
the aldehyde in ppm is read from a standard curve.

The following table represents some O.D. values for analyses conducted on a
solution containing 200 ppm aldehyde consisting of equal amounts of octanal and
trans-2-hexenal, representative of the saturated and unsaturated aldehydes in
essences, respectively. It may be noted that the smallest increase in O.D.
value occurred between 10 and 15 minutes reaction time. Although some small
loss in optical density occurred with time after addition of FeC13 these data
indicate a reasonably good color stability over a period of 20 minutes. These
results have been substantiated by decay analyses in the visible range. Par-
ticular consideration was given to the standard curve plot of optical density

(O.D.) values versus concentration of known aldehyde. Examination of the curve
for nonlinearity employing the mixed standard described above, was conducted
over a range of 10 to 60 ppm in 10 ppm increments and from 100 ppm to 800 ppm
in 50 ppm increments. The best curve obtained from plotting all O.D. values
revealed linearity from 10 ppm to 450 ppm aldehyde, above which a non-linear
relationship was encountered. Using the actual curve provided good correlation
of values obtained on dilution of several essence samples on the basis of 1:10
and 1:100. Deviation from Beer's Law may have occurred due to limitations in
the 525 mni filter at the higher O.D. measurement or a higher concentration of
HBS might be required, particularly above aldehyde concentrations of 600 ppm.

Time allowed for Optical Density (525 mnp)
reaction Time interval following addition of FeC13
(minutes) 5 10 15 20

0 .052 .049 .047 .047
5 .169 .163 .164 .162
10 .247 .239 .238 .239
15 .258 .251 .251 .252

Results of numerous tests made on essences from four processing plants,
essence recovery systems of different designs, have provided the basis for
sample preparation for the analysis of aldehydes. The recovered essence is
first diluted 1:100 in distilled water and then distilled as in the method for
determining COD. The 50 ml. volume of distillate collected is then applicable
to both aldehyde and COD measurements. Aldehyde values obtained for 13 samples
of orange essence, each representative of at least 3000 gallons of essence from
'Hamlin', blended 'Hamlin-Pineapple', or 'Valencia' orange juices have been
employed in quantitative additions to orange concentrate which had been adjusted
to 0.014% recoverable oil. Addition of each of the essence samples ranging in
aldehyde values from 1180 to 7700 ppm were made to provide a calculated 30 ppm
in the reconstituted juices. The average of values for the 13 juices was 32 ppm
total aldehyde with a range of + 4 ppm.

The COD values for the essences employed in these tests ranged from 20,000
to 76,000 ppm. Respective COD values in the reconstituted juices ranged from
365 to 750 ppm as result of essence requirements to meet the calculated aldehyde
values. Flavor scores for the 13 samples of concentrate ranged from 7 to 8 in
the good category indicating little difference between samples.

It is possible that the variable quantitative chemical composition of
recovered orange essences may be controllable on addition to FCOJ. Certainly
among the 13 essence samples employed in this study, the largest quantitative
differences between samples occurred in the total aldehyde contents. Using the
aldehyde value, as a criterion for addition of essence to concentrates, appeared
to balance the flavor by minimizing the differences between the 13 essences, as
well as between samples from the same essence system.

The oxygenated terpene (ClOH180) to total aldehyde ratios for these 13
essences ranged from 0.012 to 0.047, while the similar ratios for the reconsti-
tuted juices ranged from 0.13 to 0.22, with nine samples having ratios of 0.16
to 0.20. Analyses of fresh juices for these two major chemical classifications
have shown the Cl0H180/total aldehyde ratio for 'Valencia' orange juice to be

approximately 0.16. Therefore, addition of these particular essences to concen-
trates on the basis of 30 ppm total aldehyde provides a ClOHl80/aldehyde ratio
comparable to fresh juice.

In conclusion, the proposed HBS method for determining total aldehydes may
be used to facilitate the addition of various orange essences to concentrates.
It remains to be determined whether or not the aldehyde value can be employed
quantitatively under normal processing conditions throughout the season. It is
logical that the aldehyde content in FCOJ will serve as an index of flavor
quality, as well as contribute to more objective flavor evaluation.


1. Dougherty, M. H. 1968. A method for measuring the water soluble volatile
constituents of citrus juices and products. Food Tech. Scheduled for
publication in November.

2. Attaway, John A., Richard W. Wolford, Marshall H. Dougherty, and George J.
Edwards. 1967. Methods for the determination of oxygenated terpenes,
aldehydes, and ester concentrations in aqueous citrus essences. J. Agr.
Food Chem. 15, 688-692.

3. Wolford, R. W.,C. D. Atkins, M. H. Dougherty, J. A. Attaway, and M. A.
Ismail. 1967. Current status of recovery, characteristics, and use of
orange essence. Citrus Experiment Station Mimeo Report CES 68-8D.

4. Attaway, J. A., M. H. Dougherty, and R. W. Wolford. 1967. Oxygenated
terpene and aldehyde concentrations in orange juices during the 1966-67
season. Citrus Experiment Station Mimeo Report CES 68-8F.

5. Ismail, Mohamed A., R. W. Wolford, D. R. Petrus and M. H. Dougherty. 1968.
Colorimetric method for quantitative determination of aldehydes using
hydroxygenzensulfonamide. Manuscript in preparation.


The authors wish to express appreciation to those companies who have
supplied orange essences for these investigations; also to Louise Cherry for
conducting the many routine analyses.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-RWW

Citrus Experiment Station CES 69-6B
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-AHR

Citrus Salad Gels and Jellied Citrus Sauces

A. H. Rouse
University of Florida Citrus Experiment Station


E. L. Moore
Florida Citrus Commission
Lake Alfred, Florida

During the past year renewed emphasis has been placed by the Florida Citrus
Commission and the Florida Citrus Experiment Station on developing new citrus
products. Citrus salad gels and jellied citrus sauces are new products that
are not being manufactured at the present time. They are tasty and have the
kind of "eye-appeal" which would seem to indicate an excellent sales volume if
they are placed on the market. Natural citrus flavors are added for flavor

Broken citrus sections from sectionizing plants, which are inevitable even
with the best canning plant practices, can be utilized in the preparation of
salad gels. Also, this product could become an outlet for grapefruit and
oranges when there is an over supply of citrus. Furthermore, this process
would have the potential of developing a market demanding the use of whole,
non-surplus fruit.


An intensive study is being made of the preparation and evaluation of gel
systems that would withstand processing in the acid range of citrus juices,
have relatively low viscosity necessary for mechanical handling, and remain
stabilized (minimal syneresis) during storage.

Two tentative basic gel systems resulted from a study to obtain a gelling
agent that would meet the objectives mentioned above. One system is a properly
balanced mixture of Carrageenans-Locust Bean Gum-Low Methoxyl Pectin, named
CES formula after the Citrus Experiment Station. The other is a mixture of
Carrageenans-Locust Bean Gum, named MCI formula after Marine Colloids, Inc.
(see acknowledgment). Both systems can be used in the preparation of a pro-
cessed citrus salad gel for storage at either refrigerated (chilled) or room
temperature, also, for preparation of a jellied citrus sauce. However, the
CES system has a greater latitude in pH range, a slightly increased level of
flavor release, and slightly less viscous mixture. The MCI system has the
advantage of a slightly lower cost.

Carrageenans that have been used in the formulas are Gelcarin HWG, MWG or
FC (all predominantly kappa fraction) in combination with Gelcarin DG (pre-
dominantly iota fraction). The kappa fraction is sensitive to potassium and
gels most strongly with this cation, while the iota fraction requires the cal-
cium ion for best gelation. Potassium hydroxide or potassium salts are added

to vary the acidity of the citrus gel, thus no sodium ion is introduced. The
acidity of gels when using the MCI system becomes a critical factor below pH
3.8, while that with the CES system is not as critical. Acidity of mature
grapefruit and orange juices usually ranges from pH 3.2 to 4.2.

Low methoxyl pectin, which is used in the CES system, constitutes a
special group of pectinic acids with 3 to 7% methoxyl groups. Gel formation
is greatly influenced by the proper amount of calcium ion. Calcium can be
supplied by calcium cyclamate, a non-caloric sweetener, or other calcium salts
if sugar is used. The use of low methoxyl pectin as the sole gelling agent
would be too costly because of the high level needed to obtain a satisfactory

Thus far, water and grapefruit juice have been the most satisfactory
liquids to disperse the gelling ingredients for the preparation of citrus
salad gels. Grapefruit juice is more tolerant to heat with less flavor
change than orange juice.


Salad gels have been prepared from crushed, broken, or whole sections of
grapefruit or orange or combination thereof. A salad gel has been made using
pineapple tidbits with orange and grapefruit sections. Also, very tasty and
attractive mint and lime flavored gels were prepared using crushed grapefruit
sections with added green food color. Acidity and sweetness can be varied
and either a non-caloric sweetener or sugar used. Tangelo and tangerine salad
gels or combinations of these sections with other citrus sections are suggested,
although none of these have been prepared.

Jellied citrus sauces can be prepared from pulpy grapefruit or orange
juices or combination thereof. Use of frozen concentrated juices provides
more flexibility for preparing jellied sauces when increased soluble solids
are desired without the addition of sugar. A jellied orange sauce with 40%
soluble solids, containing FCOJ and sugar, would be similar to the jellied
cranberry sauce now on the market. A mint flavored grapefruit sauce could be
served with a variety of meat dishes.

These varieties of new citrus gels or jellied sauces are convenient foods
for the housewife to serve at mealtime. Individual moldable servings also can
be packed for cafeteria and restaurant use.


Factors used for the evaluation of citrus salad gels and sauces during
storage are primarily based upon changes in color, flavor, syneresis, and
gelation. To date, storage studies are not complete. However, the chilled
salad gels after four months in storage at 320 and 400F. have changed very
slightly. Very slight syneresis (not objectionable) has appeared in the
grapefruit salad gels but not in the orange products. The flavor of the
processed gels stored at 800F. began to change after two months, and was simi-
lar to the flavor change in single-strength canned grapefruit or orange juices
after 800F. storage.

Florida Citrus Experiment Statibn
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-AHR

You will have the opportunity to judge for yourself the potentiality of
two new gelled products at your noon meal today. The citrus salad is a
grapefruit-orange salad gel prepared from grapefruit juice and broken citrus
sections with artificial sweetener rather than sugar. The sauce is a jellied
orange sauce prepared from frozen concentrated orange juice containing 40%
soluble solids as orange solids and added sucrose.


The authors are personally indebted to Tom L. Chapman, technical repre-
sentative, and Art Moirano, manager of application research, of Marine
Colloids, Inc., Springfield, New Jersey, for supplying the carrageenans and
locust bean gum and also especially for their cooperation in assistance and
technical advice concerning their products.

Low methoxyl pectin was purchased from Products Sales Division, Sunkist
Growers, Ontario, California.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-AHR

Florida Citrus Commission and
Citrus Experiment Station CES 69-6C
Lake Alfred, Florida. 400-10/10/68-PJF

Frozen Citrus Sections and Frozen and Refrigerated Orange Slices
P. J. Fellers
Florida Citrus Commission
Lake Alfred, Florida

One answer to ever increasing citrus production is the development and
marketing of new citrus products. Creation of new markets should lead to in-
creased utilization of citrus fruit. It would appear that consumer demand for
new frozen and refrigerated citrus products exists both in the individual and
institutional markets.

Scant information is available in the literature on neither frozen citrus
sections and slices nor refrigerated (chilled) citrus slices. A review of
literature pertaining to freezing of grapefruit, as well as results obtained by
the author on the freezing of individual grapefruit sections, was reported pre-
viously at the Seventeenth Annual Citrus Processors' Meeting (CES Mimeo Report
67-11. Oct. 4, 1966).

Frozen Grapefruit Sections
Many different methods and materials have been used in attempting to success-
fully freeze grapefruit sections without the benefit of a covering sirup. To date
the best method for producing infividually frozen sections of acceptable quality
has been the simple expedient of coating them with sucrose alone or mixed with
other sugars. Three procedures were used to apply sugar(s) to sections: a)
rolling in granulated sugar, b) sprinkling granulated sugar all over to obtain a
light coating and c) dipping into a sugar sirup.

The first method mentioned above was also the first one used in applying
sugar to sections. In this test, Marsh grapefruit sections were either given no
treatment or rolled in granulated sucrose, packed in nearly gas-impermeable
composite copolymer plastic pouches, and sealed under partial vacuum before being
frozen and stored at -100F. Taste panel data in Table 1 show a definite prefer-
ence and flavor acceptability for the grapefruit sections which had been rolled
in granulated sucrose before freezing, as compared with untreated sections. For
five of six tasting over the 11-month storage period, the untreated sections
rated unacceptable in flavor with such comments from the panelists as COF (a
designation for an undesirable nondescript aroma associated with frozen citrus
products), stale, sour, bitter and nondescript off-flavors. For all samples the
data show that after an initial flavor loss, there was no further change during
the rest of the storage period. Several of the panel members commented that the
sections rolled in sucrose were too sweet, although few of these panelists
actually graded the samples down much for that reason. It was because of the
"too sweet" comments by some of the panelists, including the author, that the
idea of sprinkling the sections with a light sugar coating was developed.

Table 2 indicates taste panel results for Marsh grapefruit sections given
before freezing no treatment or light coatings of either sucrose or a mixture
of sucrose and dextrose. Sections were packaged, as indicated in the previous
paragraph, and frozen and stored at -100F. At each tasting over a year's time,
the panel as a whole found the thawed sugar-added samples more acceptable than
those without added sugar. Other similar test packs have been made and evaluated
by the panel with like results. Triangular difference-preference tests, run in
conjunction with hedionic tests, have shown a definite difference between natural
and sugar-added sections, with a definite preference for the sugar-added sections.
Use of granulated sugar(s) actually forms a sugar-sirup coating over the entire
section as the sugar granules gradually dissolve in the natural fruit juices.
For sections lightly covered with sucrose, an approximate 20% drip loss of about
200 Brix might be expected.

The use of sugar-sirup dips in the range of 30 to 500 Brix has also been a
successful method for applying sugar to sections to be individually frozen.
However, soaking of sections in high degree Brix sugar solutions resulted in
serious loss of texture.

Exactly why covering grapefruit sections with sucrose results in a better
flavored product than untreated sections is not known. Perhaps the sugar acts
in some protective way, i.e. blocking oxidative, enzymatic and/or other chemical
reactions, or acts simply as a flavor enhancer imparting added sweetness and
possibly masking off-flavors and/or excessive bitterness.

Coldpressed grapefruit oil has generally been found to enhance flavor in
frozen sections whether applied as a dip with grapefruit juice or with a sugar
sirup. As with essence addition in the production of frozen orange concentrate,
the opinions of different individuals vary greatly relative to oil addition to
sections, especially as concerns levels used. Sections dipped in grapefruit
juice containing about 0.135% or oil by weight were judged acceptable by most
panel members. Further study using both sugar and citrus oil addition to sections
is planned as promise is shown in this area. Samples of grapefruit oils "en-
trapped in a water-soluble matrix compatible with any dry mix" are being obtained
from SunkistGrowers, Inc. for use with granulated sugars to be sprinkled on

Some other observations about freezing grapefruit sections might be mentioned
here. In general, it was found, regardless of treatment, that both flavor and
texture quality of frozen sections deteriorates soon after packing but then
stabilizes at a particular level. Such a level is to some extent dependent on
both the treatment and the initial flavor quality of the fruit. As regards the
flavor of frozen grapefruit sections, it has often been found that perceptible
off-flavors do not develop, but that a severe loss of good, characteristic, fresh
grapefruit flavor occurs leaving the samples quite bland or tasteless. Also, it
should be pointed out that a significant flavor and texture variability exists
between grapefruit taken from the same lot of fruit. This has led to some
problems in quality evaluation of the frozen products.

Frozen Orange Sections

Individual Valencia orange sections were rapidly frozen by immersing them
in "Freon" food freezant for 1.5 to 2 min. The liquid "Freon" was maintained
at -200 to -250F. by surrounding the freezing chamber with a mixture of "Freon"
11 and dry ice. Using this procedure developed by the E. I. DuPont DeNemours
and Company the thawed sections did not break apart into individual juice sacs
as occurs more readily at dry ice or liquid nitrogen freezing temperatures.
Orange sections were treated in three ways before freezing. Experimental packs
are stored at -10F. and are currently being evaluated for quality.

Frozen Orange Slices

Dr. S. V. Ting of the Florida Citrus Commission's research staff prepared
some frozen slices from peeled and cored oranges for the New Citrus Products
Seminar, held in Lakeland on Dec. 4, 1967. He also designed a practical hand
corer to remove a core of about 7/8" in diameter, which has been found to be
satisfactory for seedless oranges, but not for seedy varieties which require
a larger core diameter.
Florida Citrus Commission and
Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10,68-PJF

In the work done thus far, it appears that a light sprinkling of sucrose
over the slices results in a more acceptable product flavorwise than slices
given no treatment before freezing. Dips were found to be more or less im-
practical in this case as orange slices are more fragile than sections and will
separate at the membranes if mistreated too much. Texture of the thawed
slices showed some loss due to the freezing process but has been judged accept-
able by taste panel members. Some panelists have commented unfavorably about the
presence of coarse membranes in the slices but it is believed that this problem
is not nearly as great as was originally feared it might be.

Slices of about 5/8" in width were found a good size with which to work.
Seedy orange varieties presented problems in both slicing and in the ragged
appearance of the finished slices. Slices made from Hamlin oranges showed the
neatest appearance although color of Valencia slices was better.

Refrigerated Orange Slices

Using fresh orange slices prepared from peeled and cored fruit, an attract-
ive and tasty refrigerated product in glass can be made. A covering sirup to
provide in the jar contents at equilibrium about 120 Brix and 0.05% by weight of
sodium benzoate was found to be satisfactory. Only a small amount of taste panel
data have been gathered thus far on the packs already made. The slight benzoate
taste was found objectionable in widely varying degrees to some tasters, as was
the presence of the membranes. however, for the most part this product has re-
ceived good acceptance by the panel members, with flavor and texture described as
being nearly like fresh fruit. Very recently a pack was made in which a small
amount of orange oil was added to the covering sirup to give about 0.02% oil by
weight in the finished product at equilibrium. A flavor enhancing effect by the
added oil is hoped for in this case.

Thaw-in-Bags for Packaging

Currently the only frozen citrus sections marketed are a very small pack of
canned grapefruit sections in a sugar sirup generally containing added ascorbic
acid. It is possible that the inconvenience of the long thawing times involved
limits the consumer acceptance of this product. Thawing time may be reduced by
the use of the relatively new "Thaw-in-Bag" concept of preparing and using frozen
foods. Such a pack of frozen grapefruit sections was made in March 1967, using
heat-sealable, gas-impermeable polyester film pouches. Sections were packed in
a single layer with a) nothing added, b) an equal weight of 500 Brix sucrose
sirup and c) an equal weight of 50 Brix sucrose + 100 mg of ascorbic acid/100 ml
of sirup. Pouches were vacuum sealed and placed at -100F for storage and later
quality testing. Approximate thawing time for the contents of the thaw-in-bags
in room temperature running tap water was only 10 minutes. Results of four
flavor evaluations of these packs over an 8-month, frozen storage period are
shown in Table 3. At every tasting sections packed with a covering sirup were
rated acceptable in flavor, whereas the sections frozen individually were rated
unacceptable three out of four times and barely acceptable once. All samples
lost significant amounts of characteristic fresh grapefruit flavor within one
month of packing. Texture suffered in the freezing and thawing process but was
judged acceptable. Panelist's comments associated with the sections without
sirup were sour, bitter and COF; for the sections in sirup, sweet or too sweet
were mentioned. However, in most cases when sweet or too sweet was the comment,
Florida Citrus Commission and
Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-PJF

that particular sample was rated well above the unsweetened sections. No ad-
vantage was found in using a sucrose sirup with added ascorbic acid over plain
sucrose sirup for preserving flavor quality. Results of this and other tests
suggest the efficacy of packing grapefruit and/or orange sections in sucrose
sirups, probably of less than 500 Brix, in thaw-in-bag pouches.


The author wishes to thank Dr. F. W. Wenzel and Dr. L. G. MacDowell for
their helpful suggestions pertinent to this research; those persons who have
served as taste panel members; the Continental Can Co., 3M Co., and Pollock
Paper Co. for supplying packaging materials or containers used in these
investigations; E. L. DuPont DeNemours and Co., for supplying "freon" and for
the use of a small quick freezing unit, designed and built by them.

Florida Citrus Commission and
Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-PJF

Table 1. Effect of adding granulated sucrose to Marsh grapefruit sections for freezing on flavor quality over an
11-month storage period.

Treatment before Average flavor grades for panel
freezing Months in frozen storage
1 3 5 7 9 11
dislike dislike dislike like dislike dislike
No treatment
slightly(4.2) slightly(3.9) slightly(4.1) slightly(5.6) slightly(4.1) slightly(4.0)
like neither like like neither like like like
S s r d in moderately nor dislike slightly(5.9) nor dislike slightly(6.0) moderately
Sections rolled in
in (6.6) to (5.0) (6.8)
granulated sucrose like slightly
like slightly
Eight panelists participated at each tasting.
Numbers in parentheses indicate the numerical average for the nine-point hedonic rating scale for the panel as
a whole, where "1" is dislike extremely and "9" is like extremely.

Table 2. Effect of granulated sugar coatings on flavor quality of Marsh grapefruit sections after frozen

Treatment before Average flavor grades for panel
freezing Weeks in frozen storage
9 26 52
neither like nor neither like nor dislike neither like
No treatment dislike (5.4)2 to like slightly (5.5) nordislike (4.9)

Sections sprinkled like slightly like slightly to like like slightly
with granulated sucrose (6.4) moderately (6.5) (6.3)

Sections sprinkled with a .
/Sections spin d wh a like moderately like slightly like moderately
50/50 mixture of granu- (7.1) (6.4) (7.0)
lated sucrose-dextrose(7.1) (6.4) (7.0)
lated sucrose-dextrose
See footnotes Table 1.

Florida Citrus Commission and
Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-PJF

Table 3. Flavor quality of grapefruit sections frozen individually and in covering sirups for
thaw-in-pouch use.
Average flavor grades for panel
Treatment before
Treatment befre Months in frozen storage
freezing 1 3 5 8

dislike dislike neither like neither like nor
No treatment slightly slightly nor dislike dislike to
(4.1)2 (4.2) (5.2) like slightly(5.5)
Sections packed in like neither like like like
500 Brix sucrose sirup slightly(6.4) nor dislike(5.4) slightly(6.2) slightly(6.0)

Sections packed in 500 Brix like like like like
sucrose + ascorbic acid slightly slightly moderately slightly
sirup (6.3) (5.8) (6.6) (5.8)

See footnotes Table 1.

Florida Citrus Commission and
Citrus Experiment Station,
Lake Alfred, Florida. 400-10/10/68-PJF

Citrus Experiment Station CES 69-6D
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-FWW

Current Status of the Hunterlab Citrus Colorimeter for Measuring the Color of
Frozen Concentrated Orange Juice

F. W. Wenzel
University of Florida Citrus Experiment Station
R. L. Huggart and R. W. Barron
Florida Citrus Commission
Lake Alfred, Florida

The development of the Hunterlab Citrus Colorimeter was undertaken so that
color of citrus juices or products could be measured objectively rather than
subjectively. The need for such an instrument has been evident for some time
and, being both realistic and hopeful, it may be that in the future when pro-
duction of frozen concentrated orange juice becomes computerized, an in-stream
instrument will blend concentrates of different color so that uniformity in the
color of frozen concentrated orange juice will be a fact rather than a desire.

The Florida Citrus Commission in 1962 contracted with Hunter Associates
Laboratory, Inc., to develop an instrument for measuring color of citrus juices.
An experimental prototype instrument was delivered to the Florida Citrus Commission
in 1963 and its evaluation was undertaken at this Station. An improved Hunterlab
Citrus Colorimeter (HCC) became available in 1965 and four of these instruments
were purchased by the Florida Citrus Commission. Three of these were assigned
during the 1965-66 and 1966-67 citrus seasons to the quality control laboratories
of three Florida commercial processing plants and used to obtain redness (CR) and
yellowness (CY) color values of reconstituted frozen concentrated orange juices.
The other colorimeter has been used at this Station. The USDA Consumer and
Marketing Service also purchased one of these colorimeters for the Winter Haven,
Florida, laboratory of the Fruit and Vegetable Division Processed Food Inspection.

Reports on the use and evaluation of the Hunterlab Citrus Colorimeters, both
the prototype and the improved models, have been presented at each of these
Annual Citrus Processors' Meetings since 1963. Papers relative to these investi-
gations have been published in Food Technology and the Proceedings of the Florida
State Horticultural Society. These are listed at the end of this report and
reprints are available.

Relation between visual color scores and Hunterlab Citrus Colorimeter Values
for reconstituted frozen concentrated orange juices. During the past year
color data available from the examination of 428 samples of commercial frozen
concentrated orange juice, packed during the 1965-66 and 1966-67 citrus seasons,
were summarized and statistically analyzed using least squares and short-cut
grouping methods. These products, when available, were collected semi-monthly
during each season from 25 commercial Florida plants.

Visual color scores of the reconstituted orange juices were determined by
each of the authors and one other staff member. Each juice was filled into a
1-inch-OD clear glass, screw cap culture tube. Color of the juice was scored
by comparing it, according to specified procedures, with that of four plastic
USDA Orange Juice Color Standards. Color scores of 36 through 40 were given to
the juices. The means of the total points given by the judges were used in the
statistical analyses.


The redness (CR) and yellowness (CY) values of the reconstituted juices were
measured using the Hunterlab Citrus Colorimeter, following recommended procedures
for its use.

Frequency distribution of visual color scores for the 428 reconstituted
orange juices are shown in Table 1.

Table 1. Frequency distribution of visual color scores for
reconstituted midseason and late season samples of commercial
frozen concentrated orange juice packed during two citrus seasons.
1965-66 1966-67
Visual Mid Late Mid Late
color No. of samples No. of samples
scores 114 94 118 102
% of samples % of samples
40 11.7 -
39 3.5 57.4 33.3
38 7.1 27.6 3.4 55.9
37 44.7 2.2 48.3 10.8
36 44.7 1.1 48.3 -

The ranges and means for the HCC redness and yellowness values for the
reconstituted orange juices are presented in Table 2.

Table 2. Ranges and means for Hunterlab Citrus Colorimeter
redness and yellowness values for reconstituted midseason and
late season samples of commercial frozen concentrated orange
juice packed during two citrus seasons.
Hunterlab Citrus Colorimeter
1965-66 Season 1966-67 Season
Range Mean Range Mean
Redness values CR
Mid 26.2-43.6 32.7 26.2-38.3 31.2
Late 32.1-45.2 40.3 31.0-43.1 39.0

Yellowness values CY
Mid 74.7-86.8 80.2 74.3-84.3 79.0
Late 77.3-88.9 85.1 77.7-87.9 83.5

Simple correlation coefficients (r) calculated between visual color scores
of the reconstituted orange juices and the HCC values are listed in Table 3.
All of these coefficients were significant at the 99% level of confidence.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-FWW

Table 3. Simple correlation coefficients between visual color
scores and Hunterlab Citrus Colorimeter redness and yellowness
values for reconstituted samples of commercial frozen concentrated
orange juice packed during two citrus seasons.
1965-66 1966-67
Mid Late Mid Late
No. of samples No. of samples
114 94 118 102

Redness CR 0.855** 0.799** 0.746** 0.800**

Yellowness CY 0.880** 0.834** 0.640** 0.616**

Significant at 99% level of confidence.

Simple correlation coefficients of 0.922 and 0.864 between the HCC-CR and
CY values were obtained when the 1965-66 and 1966-67 redness and yellowness
values for the reconstituted juices were used.

A multiple correlation coefficient (R) of 0.994 was found between visual
color scores and both the HCC CR and CY values, using only data obtained from
examination of the 220 samples of 1966-67 concentrates. The corresponding co-
efficient of determination (R2) was 0.988 which indicates that over 98% of all
variations in the visual color scores can be explained by variations in the
redness and yellowness of the reconstituted juices.

Precision of the Hunterlab Citrus Colorimeter. The precision of an instru-
ment is the ability to duplicate results with one instrument or with different
individual replicate instruments. Thus, it is dependent upon the variability
both within a single instrument and between different instruments.

During the past year data for statistical analysis to determine the pre-
cision of the Hunterlab Citrus Colorimeters were obtained, under carefully
controlled conditions, by the USDA Consumer and Marketing Service at the Pro-
cessed Foods Laboratory in Winter Haven. Five inspectors used 5 different
instruments to obtain CR and CY values of 5 different reconstituted orange juices
having a range of 36 to 40 score points. Statistical analysis by the USDA of
the data obtained answered some questions but provoked others relative to the
precision of the instruments. Of primary concern was that of variation between
the 5 instruments.

It was decided that three instruments, then in use at cooperating commercial
processing plants to obtain color values of canned or bottled orange or grape-
fruit juices, should be returned to the Citrus Experiment Station. This was done
and then three of the four instruments, owned by the Florida Citrus Commission,
were shipped to the Hunter Associates Laboratory since Mr. Hunter had offered to
investigate and identify the sources that possibly might be causing the vari-
ations between the colorimeters, and also, to propose a remedy. In a report on
August 28, he included the results of his investigation, together with data on
which his conclusions and recommendations were based. The pertinent portions
of this report will now be discussed.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-FWW

Spectrometer curves of the sensitivities of the three Florida instruments
indicated that there were small, but definite spectral differences between them.
Also, with two of the colorimeters, the small projection lens next to the light
source was solarized resulting in a definite pink appearance. This could have
produced errors in spectral responses. Such things as these would cause some
variability within and between instruments. Of course, a discolored lens can be
replaced with a new one.

Spectral intercomparisons of five reconstituted orange juices and three of
the USDA Orange Juice Color Standards were made. Results are shown in Figure 1.
Spectral differences between instruments would not produce disparities in the
CR and CY readings if the juices and the standards were identical spectrally.
However, it can be seen from Figure 1 that the curves for the OJ standards are
very definitely different in shape from those for the orange juices. There is a
very definite dip in spectral reflection in the curves for the OJ standards
between 520 and 570 millimicrons while there is no corresponding dip in the
curves for the juice samples. The combination of errors in spectral responses,
indicated in the preceding paragraph, with the spectral differences between
juices and the OJ standards are almost certainly the major causes of the in-
strument disparities in CR and CY readings. The proposed solution to the prob-
lem of the variations between the colorimeters, recommended by Mr. Hunter, was
the use of a specific calibration technique. This involves assigning different
numbers for the same OJ standard to the different instruments with which it is
used. The justification for this technique is the presence of an off-setting
error, such as the simultaneous spectral differences between (1) standards and
juices and (2) different instruments. In Figure 2 are plotted the deviations
from the average reading for each of 13 juices on each of the five instruments
used. A single standard (Hunterlab OJ5) was used for all of these measurements.
The improvement possible by using the specific calibration technique is shown in
Figure 3. For the data plotted in Figure 3, results on six juices from each of
four instruments were intercompared. A value was selected for the OJ4 standard
for each instrument so as to give minimum differences between the instruments on
the six juices. Values assigned the single OJ4 standard were:

Instrument No. 102 104 105 106
OJ4 CR value 32.2 31.2 31.5 31.6

Instrument #2 was not used in the latter part of the study
because of its non-standard features.

The disparities shown in Figure 1 largely disappear by assigning to the
same standard,values which vary from 31.2 to 32.2. The deviation from the
average reading for each of the juices represented in Figure 2 is 0.4 CR unit,
while for the data represented in Figure 3, it is about 0.1 CR unit.

After assignment of specific calibration values to the Hunterlab master
set of OJ standards, similar off set values can be assigned to the standards
with each instrument.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-FWW

Following are three publications containing information on the development,
use and evaluation of the Hunterlab Citrus Colorimeter.

Barron, R. W., Maraulja, M. D. and Huggart, R. L. 1967. Instrumental and
visual methods for measuring orange juice color. Proc. Fla. State Hort. Soc.
80, 308.

Huggart, R. L., Barron, R. W. and Wenzel, F. W. 1966. Evaluation of
Hunter citrus colorimeter for measuring the color of orange juices. Food
Technol. 20, 109.

Hunter, R. S. 1967. Development of the citrus colorimeter. Food Technol.
21, 100.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-FWW

40 -

30 -


20 -

10 -

From report by Richard S. Hunter
Hunter Associates Laboratory, Inc.
Fairfax, Va. 8/28/68.

500 550 600
Wavelength in Millimicrons

Figure 1. Spectral reflectance curves for three plastic standards (OJ2,
OJ3, OJ5) and for 5 reconstituted orange juices.

+2 -

4 +1 104


0 106


-1 -

-2 -

28 30 32 34 36 38 40 4

Citrus Red (CR) Values

Figure 2. Differences for 5 instruments of the CR readings from the
averages for 4 instruments (#2 omitted). All instruments adjusted to
read 29.2 for Hunterlab standard. The vertical separation of these curves
is evidence of the spectral error and spectral differences between plastic
standards and juices. These errors can be largely corrected by the speci-
fied calibration offsets computed from data and shown by arrows.

From report by Richard S. Hunter
Hunter Associates Laboratory, Inc.
Fairfax, Va. 8/28/68

_- _102


_-.--._ 105


Citrus Red (CR) values

Figure 3. Differences of
plotted on the same scale as
of standard values have been
technique of calibration.

CR readings from the average for 4 instruments
in Figure 2. The specific calibration adjustment
made to show the improvement possible by the

From report by Richard S. Hunter
Hunter Associates Laboratory, Inc.
Fairfax, Va. 8/28/68.

+0.5 -


-0.5 -

+0.5 -


-0.5 -

+0.5 -


-0.5 -

+0.5 -


-0.5 -



~~~----- -


Citrus Experiment Station CES 69-6E
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-SKL

Fermentation Products from Citrus Molasses

S. K. Long
University of Florida Citrus Experiment Station
Lake Alfred, Florida

Two fermentation projects are in progress, one on the production of citric
acid and the other on the production of high proof ethyl alcohol. Both of these
fermentations utilize citrus molasses as the raw material.

Suitability of Citrus Molasses for Fermentation

Citrus molasses, in spite of its low cost, is an extremely valuable raw
material for fermentation use. The most important constituent is the sugar.
Citrus molasses contains 40-45% total sugars, of which approximately 20% is
sucrose, with the remainder being glucose and fructose. Based upon these figures,
a ton of molasses contains approximately 800-900 pounds of sugar. Using an
average market price of $20.00 per ton, the cost of the sugar in citrus molasses
is about 2.2 2.5 cents per pound. This price for sugar in citrus molasses is
much cheaper than that in corn or beet molasses and is about the same price as
that in cane blackstrap molasses.

The remaining constituents of citrus molasses (Table 1) are similar to
those of cane blackstrap. Blackstrap molasses is now used extensively in
industrial fermentations while citrus molasses is used only to a limited extent
for this purpose. There seems to be little reason why citrus molasses cannot
replace blackstrap in many of these fermentations.

As an aid in establishing new fermentation outlets for citrus molasses, it
is suggested that the basis for pricing molasses be changed from simply dollars
per ton to that of cents per pound of sugar. Since sugar is the only constitu-
ent being fermented, its cost per pound will be the determining factor for the
use of citrus molasses in industrial fermentations. In addition, it might be
noted that fermentation industries might prefer less sugar than that found in
710 Brix molasses since this is much too concentrated for fermentation use. For
example, molasses diluted to 200 Brix might be preferred. The only way to pro-
vide realistic pricing of such molasses would be on the basis of sugar content.

The Citric Acid Fermentation

Approximately 100 million pounds of citric acid are produced annually in
the U. S., primarily by fermentation. This fermentation has been a commercial
process for many years and, today, provides about 90 per cent of the world
supply of citric acid. Citric acid is produced from various sugars by the mold
Aspergillus niger, usually employing such cheap raw sources of sugar as beet
and cane blackstrap molasses. Only one reported attempt has been made to pro-
duce citric acid from citrus molasses (Gaden, et al. (1954), and this was
unsuccessful. According to published analyses, citrus molasses contains all of
the constituents required for fermentation by Aspergillus niger and, therefore,
should be suitable for this purpose.

Besides having a plentiful supply of cheap raw material, an additional
attractive feature of this fermentation is the fact that a ready market for
citric acid already exists in the State of Florida, where various industries
utilize approximately 5 million pounds annually.

This project was designed to utilize both canning plant waste water and
citrus molasses in the fermentation process. The preferred waste waters would
include those of high B.O.D. content which impose the greatest load on dis-
posal operations. Segregation of wastes would be required to avoid toxic
materials such as detergents and alkalies. Examples of utilizable wastes are
shown in Table 2.

Although these wastes have high B.O.D. content, they are too dilute for
fermentation. Citrus molasses, on the other hand, is too concentrated. By
using waste water to dilute the molasses, maximum utilization of both would be
obtained. The optimum sugar concentration for this fermentation is about 17
per cent total sugar; therefore, it is estimated that 600-700 gallons of waste
water could be utilized in diluting 1 ton of molasses to the desired concen-
tration. Flash heat treatment of the waste water to remove peel oil, if
present, would be necessary to prevent the toxic effects of this material.

The development of this fermentation was carried out in 2 phases, a
laboratory-scale fermentation and a pilot-plant operation. The laboratory
phase has been completed and operations have now progressed to the pilot-plant
phase which is still under development.

In the laboratory phase, basic information about the behavior of A. niger
in citrus molasses was obtained as well as the response of this organism to
variations in the molasses medium. It was found that the optimum sugar con-
centration was 15-17%, this being roughly equivalent to molasses diluted to
200 Brix. The natural nitrogen content of molasses of 3-4 per cent was found
to be satisfactory.

Although citrus molasses contains vitamins and growth factors, such as free
amino acids, this was found to be of little consequence since A. niger requires
no added growth factors. It was also found that this organism, if permitted to
metabolize normally, would convert the sugars to additional A. niger plus C02
and water at the expense of citric acid. This problem was handled by adding
toxic agents, such as potassium ferrocyanide, to the medium. This compound
inhibited the action of the specific enzymes responsible for further metabolism
of citric acid, resulting in an accumulation of the desired compound.

The citric acid fermentation is a highly aerobic process; therefore, lab-
oratory scale fermentations were shaken vigorously to aerate the medium.
However, it was found that shaking provided inadequate aeration for maximum
acid production. It was eventually established that a combination of vigorous
shaking and sparging with pure oxygen at 0.5 cfm were needed to satisfy the
oxygen demand of the cultures.

The fermentation has now progressed to a 130-L pilot plant fermentor
operation. Although some problems were encountered in scaling-up from the
small fermentation vessels to the larger fermentor, these problems are gradu-
ally being resolved. At the present time, yields of approximately 30 per cent
of theoretical are being obtained. The project will be considered successful
and economically feasible if we can increase the yield to as much as 70 per
cent of theoretical.
Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-SKL

Economics of the Citric Acid Fermentation

Calculation of the yield of citric acid, which might reasonably be expected,
indicates that, with yields of 50-70 per cent of theoretical, approximately 450-
630 pounds of citric acid having a gross value of $135-189 could be produced per
ton of molasses. By comparison, the current price of molasses alone is $22.00
per ton. These figures do not include the additional savings realized by reduc-
ing the waste treatment load due to consumption of waste waters.

Production of High Proof Ethyl Alcohol by Fermentation

Considerable work was done on an alcoholic fermentation of citrus wastes
by U.S.D.A. scientists in Winter Haven in 1942 (Nolte, et al. (1942). They
were able to produce ethyl alcohol from citrus press liquor but in such small
quantity that it was industrially unfeasible. They found that concentration of
the press liquor was necessary to obtain good yields of alcohol. This research
report apparently attracted little interest since, 26 years later, there is
still only one distillery in operation in the entire State. This one is lo-
cated in Lake Alfred,

Within the last few months, however, presumably as the result of the tax
concession allowed by Florida, two major distillers have moved into the citrus
processing areas of the State. One of these companies is presently engaged
only in a bottling operation using spirits produced elsewhere; however, it seems
predictable that they may soon be producing their own spirits in Florida.

A third major distiller proposes to begin construction of a plant costing
more than $1,000,000 in this area around the first of 1970. This plant will be
capable of producing more than 1,000,000 proof gallons of beverage alcohol per

It might be noted here, that the Citrus Experiment Station was responsible
for bringing this latter Company into the State. Under a grant support arrange-
ment with the Institute of Food and Agricultural Sciences, the fermentation
process for their entire operation was developed at the Station. We feel that
operations of this kind will result in a greater and more stable market for
citrus molasses and, consequently, greater returns to the Citrus Industry.

This fermentation process employs dilute citrus molasses under strictly
controlled conditions of temperature and agitation. Adjustment or control of
pH were unnecessary. All of this fermentation work was done in the pilot-
fermentor previously mentioned. The usual laboratory-scale operation was
omitted since time was an important factor. All details of the fermentation
process should be completed within the next month.

Economics of the Alcoholic Fermentation

The raw material cost for producing beverage alcohol from citrus molasses
will be less than 50 per cent of that now paid at Northern points. No figures
are available for the additional costs of distillation since this is not
within the scope of our investigation.

The tax concession provided by the State of Florida is as follows: Distilled
spirits: distilled outside the State of Florida bears an excise tax of $3.75 per
proof gallon. Distilled spirits distilled in the State from Florida products and
sold in Florida, bears an excise tax of only 0.474 cents per proof gallon.


Gaden, E. L., D. N., Petsiavas, and J. Winaker. 1954. Microbiological product-
ion of riboflavin and citric acid from citrus molasses. J. Agr. Food Chem.
2, 632-638.

Nolte, A. J., H. W. vonLoesecke, and G. N. Pulley. 1942. Feed yeast and
industrial alcohol from citrus waste press juice. Ind. Eng. Chem. 34,

Hendrickson, R., and J. W. Kesterson. 1965.
Composition, technology, and utilization.

By-products of Florida citrus.
Univ. Fla. Agr. Expt. Sta. Bull.

McNary, R. R. 1965. The treatment and disposal of citrus processing waste
water. Mimeo Rept., Short Course, Instit. Food Technol., Univ. Fla.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-SKL

Table 1. Comparison of Citrus and Blackstrap Molasses1

Citrus Molasses Blackstrap
Constituent Commercial Laboratory Louisiana Cuban

0 Brix 72.0 73.1 90.7 87.2
Sucrose 19.6 26.1 30.1 37.3
Reducing sugars % 22.9 24.9 26.4 16.6
Total sugars % 43.5 52.4 58.0 55.8
Ash, carbonate % 4.7 3.0 10.8 10.9
Protein (N x 6.25) % 4.1 3.6 1.6 2.1

pH 5.0 5.9 5.7 5.5

Average of 36 samples

Average of 16 samples

Hendrickson, R., and J. W. Kesterson, 1965.

Table 2. B.O.D. Content of Citrus Processing Waste Waters2


Fruit Washing
Juice Extraction
Juice Evaporator Condenser Water
Molasses Evaporator Condenser Water
Essential Oil Recovery
Peel Bin Drip
Press Liquor

ppm B.O.D.

5,000- 10,000
20,000- 45,000

McNary, R. R., 1965.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida. 425-10/10/68-SKL

Citrus Experiment Station CES 69-6F
and Florida Citrus Commission,
Lake Alfred, Florida. 400-10/10/68 RH


R. Hendrickson and J. W. Kesterson
Institute of Food and Agricultural Sciences
Lake Alfred, Florida

At this time, our experimental feed mill has been in operation for almost
five years. Completed in November of 1963, it was almost immediately (December
3, 1963) used to process into dried citrus pulp the peel of fruit, that had been
previously treated with a new pesticide. The paramount need for accurate residue
information and samples for establishing tolerances was one of the motivating
forces for obtaining funds and equipment to provide a feed mill at the Citrus
Experiment Station. Currently the determination of pesticide residues that re-
main on citrus fruits after harvesting is still one of the more important
problems facing this and other agricultural industries.

In the past 5 years, the facility has helped to expedite the establishment
of pesticide residue tolerances for an impressively long list of chemicals that
are needed in the production and processing of citrus. Although the greater
number of trials have involved pre-harvest pesticides for citrus, investigations
have recently been concerned with post-harvest chemicals, mainly fungicides.
This is probably the natural result of the recently established Florida law re-
quiring all citrus destined for fresh shipment to be treated with an approved

Operating under University of Florida policy, the Citrus Experiment Station
has requested and received grant-in-aid funds from the respective pesticide
manufacturer to defray the cost of operating a facility for his benefit. At
the end of this past season an important anniversary was reached in that grant-
in-aid funds, earned in operating the pilot plant which has proven to be very
useful in obtaining information of importance to the citrus processing industry
had finally totalled a sum equal to the purchase price of the facility. How-
ever, additional credit must be given in this case to Dan B. Vincent whose
company so generously installed a complete facility for less than cost.

The many kinds of equipment involved in preparing samples in a pesticide
trial have been schematically depicted in the attached figure. Slides will be
shown to illustrate the level of pesticidal residue that can be expected in a
number of citrus products when the fruit have been treated with a preharvest or
post harvest chemical. By surveying the residue results in a schematic arrange-
ment, the slides will emphasize the importance of providing an efficient fruit
washing system in each citrus processing plant. In that larger and larger
quantities of citrus are processed into citrus by-products each year at a sub-
stantial profit, there is a greater obligation for processors to evaluate the
protection given to the reputation of our citrus by-products by more carefully
washing the fruit.

One result of having carried out many trials wherein 10 or 15 box lots of
citrus are processed into many by-products is an accumulation of statistics on
expected yield of dried citrus pulp and juice under known conditions as shown
in the following Table. Recovery of peel oil and finisher pulp will be
illustrated by slide.

Dried Citrus Pulp and Juice from Citrus
Type Juice Drying Pulp Pulp
Fruit % Ratio #/Box % Yield
Valencia 56.8 3.8:1 10.4 11.4
Valencia 60.0 3.9:1 9.1 10.2
Valencia 60.7 4.3:1 8.2 9.1
Pineapple 57.7 3.6:1 10.9 11.8
Pineapple 56.2 3.3:1 12.6 13.3
Marsh 48.5 5.4:1 7.8 9.5
Marsh 44.5 4.6:1 10.2 12.1
Duncan 44.0 4.7:1 10.0 11.9

Time permitting, other trials concerned with modifying dried citrus pulp,
drying seeds, drying leaves, drying unlimed peel products, and preserving
carotenoid pigment will be discussed.

Citrus Experiment Station and
Florida Citrus Commission,
Lake Alfred, Florida. 400-10/10/68 RH


Soap Water
R o

a p i-L




Peel, rag, bits
a Seeds 1 A


Peel, rag, seeds

Peel hopper

screen em.

I storage


I----Citrus pulp
---- Citrus meal

Press liq.
Press liq.


Fines sep.

--- --- -







Florida Citrus Commission and
Citrus Experiment Station CES 69-6G
Lake Alfred, Florida. 450-10/10/68-RWB

Some Characteristics of Commercial Frozen Concentrated Orange Juices Processed
During the 1965-66, 1966-67, and 1967-68 Citrus Seasons

R. W. Barron and M. D. Maraulja
Florida Citrus Commission
Lake Alfred, Florida

Samples of commercial frozen concentrated orange juice were examined for
flavor and color during the 1967-68 citrus season. The products were collected
semi-monthly from 23 commercial plants during the period from December 15, 1967
to June 15, 1968, inclusively. A total of 197 samples were examined of which
113 were midseason and 84 were late season packs. All data are summarized in
Tables 1-6, as well as that for samples collected and examined during 1965-66
and 1966-67.

Flavor evaluations (Table 1) are based upon the opinions of flavor panel
members after each of the reconstituted juices had been tasted in accordance
with instructions given on the next page. The percentage of all samples that
were graded "very good" for the 1965-66, 1966-67, and 1967-68 seasons was 47%,
54%, and 25%, respectively, and for those graded "good" was 50%, 45%, and 72%.
Thus, some decrease in the flavor quality of the 1967-68 midseason and late
season products is evident. However, the percentages of samples graded "very
good" and "good" totaled 97%, 99%, and 97% for the three seasons. None of the
products were graded "poor".

Frequency distributions of the Hunter Color Difference Meter "Rd" (lightness),
"a" (redness), and "b" yellownesss) values for both the concentrates and the re-
constituted juices for the three seasons are shown (Tables 2, 3, and 4). Com-
parison of these data for the midseason samples indicate that the color of the
1967-68 reconstituted juices was slightly better than that of those from the
1966-67 season, but not as good as the color of the 1965-66 juices. There were
only very slight differences in the color of the late season reconstituted
juices from the three seasons.

The relation between the average Hunter Color values and the date of pack-
ing for the orange concentrates, as well as that for the reconstituted juices,
is reported (Tables 5 and 6). The midseason and late season packs for the three
seasons were separated on the basis of a distinct change in redness of the con-
centrates when Valencia oranges became available for processing; also, to some
extent on the number of plants in operation.


The 625 samples of Florida frozen concentrated orange juice examined for
this study were supplied by 25 companies and their cooperation was appreciated.

Thanks are extended to personnel of the U.S.D.A. Agricultural Marketing
Service, Winter Haven, Florida, for their assistance in obtaining the samples
at the concentrate plants.




Flavor Evaluation of Frozen Concentrated Orange Juices

Reconstituted commercial frozen orange concentrates.

(a) Grade for flavor on the following basis and do not
consider other factors, such as color or separation.

Very good

Very poor

Use excellent, good, or fair only if the juice in your
opinion is acceptable as frozen orange concentrate, and
therefore, would be repurchased by you.

(b) If you score a sample of juice 4 or lower, indicating
that the product is not acceptable as frozen orange con-
centrate, and therefore, would not be repurchased by you,
then indicate all of the flavor defects responsible for
the poor flavor quality.

Indicate flavor defects using only the following descript-
ive terms. If necessary, other terms will be added to
this list. If you are not sure of the type of flavor defect
in any juice, which you score 4 or lower, then indicate that
it is nondescript.

Flavor Defects

Too sour (acid)
Too sweet
Excessive peel oil
Too bitter
Too astringent

Castor oil

Immature fruit
Overmature fruit
Stale fruit

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/10/68-RWB

Taste panel members who graded the flavor of the frozen concentrated orange
juices made possible the flavor evaluations summarized in this report. Members
of the taste panel during the 1967-68 season were: M. H. Dougherty, Alice
Barber, Louise Cherry, R. W. Olsen, Roger Patrick, M. A. Ismail, S. K. Long,
F. W. Wenzel, R. W. Wolford, R. W. Barron, M. D. Maraulja and P. J. Fellers.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/10/68-RWB

Table 1. Frequency distribution of flavor grades for samples of commercial
frozen concentrated orange juices collected from Florida processing plantsI.
1965-66 1966-67 1967-68
Flavor Number of % of Number of % of Number of % of
grade2 samples samples samples samples samples samples

Midseason Packs1
Very Good 51 45 67 57 20 18
Good 57 50 51 43 88 78
Fair 6 5 0 0 5 4
Poor 0 0 0 0 0 0
Totals 114 100 118 100 113 100

Late Season Packs
Very Good 47 50 51 50 30 36
Good 47 50 49 48 53 63
Fair 0 0 2 2 1 1
Poor 0 0 0 0 0 0
Totals 94 100 102 100 84 100

Total Packs for Entire Season
Very Good 98 47 118 54 50 25
Good 104 50 100 45 141 72
Fair 6 3 2 1 6 3
Poor 0 0 0 0 0 0
Totals 208 100 220 100 197 100
1Samples collected semi-monthly from December through June, inclusively, during
each processing season. Samples of midseason packs collected from December 15
to March 15, inclusively, for the 1965-66 and 1966-67 seasons; and from
December 15 to April 1, inclusively, for the 1967-68 season.

Based on the evaluation of the flavor of 208 samples for the 1965-66 season,
220 samples for the 1966-67 season, and 197 samples for the 1967-68 season.
The taste panel followed instructions as previously indicated. Each of the
reconstituted juices from the concentrates for all 3 seasons were tasted
once; however, some samples were examined several times if it was considered
necessary. The data for the 1965-66 season are based on 2200 individual
flavor grades; for the 1966-67 season, on 2007 grades, and for the 1967-68
season on 1714 grades.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/10/68-RWB

Table 2. Comparison of frequency distribution tables of Hunter "Rd" values for samples from midseason and late
season packs of commercial frozen concentrated orange juices collected semi-monthly during the 1965-66, 1966-67, and
1967-68 citrus seasons.
Hunter Concentrates
Color Midseason Late season Total
Difference samples-% samples-% samples-%
Meter Season 1965-66 1966-67 1967-68 1965-66 1966-67 1967-68 1965-66 1966-67 1967-68
Rd Samples 114 118 113 94 102 84 208 220 197
16.0-16.9 - - - 3.2 3.9 1.2 1.4 1.8 0.5
17.0-17.9 - - - 8.5 12.8 4.8 3.9 5.9 2.0
18.0-18.9 1.8 0.9 - 10.6 18.6 8.3 5.8 9.0 3.6
19.0-19.9 12.3 1.7 3.5 20.2 21.5 17.9 15.9 10.9 9.6
20.0-20.9 24.5 5.9 8.0 17.0 16.7 15.5 21.1 10.9 11.2
21.0-21.9 15.8 13.6 8.0 12.8 9.8 20.2 14.4 11.9 13.2
22.0-22.9 7.0 18.5 10.6 11.7 9.8 11.9 9.1 14.5 11.2
23.0-23.9 7.0 15.2 23.0 8.5 3.9 8.3 7.7 10.0 16.8
24.0-24.9 14.0 12.7 19.4 4.3 2.0 9.5 9.6 7.7 15.2
25.0-25.9 9.6 11.9 6.2 2.1 1.0 1.2 6.3 6.8 4.1
26.0-26.9 9.3 7.6 14.1 0.0 - 1.2 2.9 4.1 8.6
27.0-27.9 1.8 7.6 2.7 1.1 - - 1.4 4.1 1.5
28.0-28.9 0.9 0.9 2.7 - - - 0.5 0.5 1.5
29.0-29.9 - 0.9 1.8 - - - - 0.5 1.0
30.0-30.9 - 1.7 - - - - - 0.9
31.0-31.9 - 0.9 - - - - - 0.5




Reconstituted Juices
- 1.0
- 2.9
12.8 17.7
18.1 32.4
21.3 18.6
23.4 18.6
13.8 2.9
5.3 5.9
5.3 -






Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/10/68-RWB

Table 3. Comparison of frequency distribution tables of Hunter "a" values for samples from midseason and late
season packs of commercial frozen concentrated orange juices collected semi-monthly during the 1965-66, 1966-67 and
1967-68 citrus seasons.
Hunter Concentrates
Color Midseason Late season Total
Difference samples-% samples-% samples-%
Meter Season 1965-66 1966-67 1967-68 1965-66 1966-67 1967-68 1965-66 1966-67 1967-68
a Samples 114 118 113 94 102 84 208 220 197
10.1-11.0 - - 0.9 5.3 1.0 - 2.4 0.5 0.5
9.1-10.0 1.8 - - 14.9 4.9 - 7.7 2.3 -
8.1- 9.0 0.9 - 0.9 41.5 20.6 16.7 19.2 9.6 7.6
7.1- 8.0 2.6 0.9 6.2 25.5 52.0 40.4 13.0 24.5 20.8
6.1- 7.0 14.9 6.8 9.7 11.7 18.6 27.4 13.5 12.3 17.3
5.1- 6.0 28.1 20.3 22.1 1.1 2.9 10.7 15.8 12.3 17.3
4.1- 5.0 35.9 37.2 29.2 - - 3.6 19.7 19.9 18.3
3.1- 4.0 14.9 24.6 26.6 - - 1.2 8.2 13.1 15.7
2.1- 3.0 0.9 10.2 4.4 - - - 0.5 5.5 2.5
1.1- 2.0
Less than 1.1 - - - - - - - - -

Reconstituted Juices
0.0 to -0.9 - - - 4.3 - - 1.9
-1.0 to -1.9 1.8 - 1.8 27.6 5.9 6.0 13.5 2.7 3.6
-2.0 to -2.9 2.6 - 1.8 40.4 41.2 37.0 19.7 19.1 16.7
-3.0 to -3.9 12.3 1.7 6.2 21.3 42.1 42.7 16.3 20.5 21.8
-4.0 to -4.9 29.8 12.7 18.6 6.4 9.8 9.5 19.3 11.4 14.7
-5.0 to -5.9 45.6 42.4 38.0 - 1.0 3.6 25.0 23.1 23.4
-6.0 to -6.9 7.9 37.3 27.4 - - 1.2 4.3 20.0 16.2
Less than -6.9 - 5.9 6.2 - - - - 3.2 3.6

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/10/68-RWB

Table 4. Comparison of frequency distribution tables of Hunter "b" values for samples from midseason and late
season packs of commercial frozen concentrated orange juices collected semi-monthly during the 1965-66, 1966-67 and
1967-68 citrus seasons.
Hunter Concentrates
Color Midseason Late season Total
Difference samples-% samples-% samples-%
Meter Season 1965-66 1966-67 1967-68 1965-66 1966-67 1967-68 1965-66 1966-67 1967-68
b Samples 114 118 113 94 102 84 208 220 197
More than 35.9 13.2 5.1 - 7.4 - - 10.6 2.7 -
35.0-35.9 13.2 1.7 - 16.0 - - 14.4 0.9 -
34.0-34.9 28.9 5.9 6.2 19.1 1.0 - 24.5 3.6 3.6
33.0-33.9 21.0 14.4 10.6 30.9 1.0 6.0 25.5 8.2 8.6
32.0-32.9 20.2 21.1 21.2 20.2 8.8 15.5 20.2 15.5 18.8
31.0-31.9 3.5 22.2 35.4 6.4 17.7 15.5 4.8 20.0 26.9
30.0-30.9 - 22.8 17.7 - 26.4 26.1 - 24.5 21.3
29.0-29.9 - 5.9 8.0 - 24.5 25.0 - 14.6 15.2
28.0-28.9 - 0.0 0.9 - 19.6 10.7 - 9.1 5.1
27.0-27.9 - 0.9 - - 1.0 1.2 - 0.9 0.5

Reconstituted Juices
More than 33.9 - - -
33.0-33.9 1.8 0.9 - 11.7 - - 6.3 0.5 -
32.0-32.9 16.7 3.4 - 46.8 - - 30.3 1.8 -
31.0-31.9 29.8 0.9 - 36.2 1.0 - 32.7 0.9 -
30.0-30.9 22.8 11.0 3.5 5.3 4.9 2.4 14.9 8.2 3.0
29.0-29.9 26.3 25.4 23.9 - 17.8 17.9 14.4 21.8 21.3
28.0-28.9 2.6 40.6 38.9 - 44.0 34.5 1.4 42.2 37.1
27.0-27.9 - 14.4 24.8 - 27.4 40.4 - 20.5 31.5
26.0-26.9 - 3.4 8.0 - 4.9 4.8 - 4.1 6.6
25.0-25.9 - - 0.9 - - - - - 0.5

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/10/68-RWB

Table 5. Relationship of date of packing to average Hunter Color values for commercial frozen concentrated orange
juices collected from Florida processing plants.
Hunter Color Difference Meter average values for concentrates
1965-66 season 208 samples 1966-67 season 220 samples 1967-68 season 197 samples
Approx. Number Number Number
date of Rd a b of Rd a b of Rd a b
packed samples samples samples
12/1 - - - - - - - - -
12/15 8 22.9 5.6 33.8 4 23.6 4.5 34.8 10 22.8 5.0 31.4
1/1 18 22.9 4.6 33.7 15 25.0 4.3 34.8 16 23.2 4.6 31.6
1/15 21 21.8 4.4 33.3 23 24.6 3.7 32.1 21 23.2 4.7 32.4
2/1 23 23.2 5.0 34.3 21 24.0 4.2 31.5 21 23.0 4.9 32.1
2/15 21 22.1 5.3 34.6 20 24.0 4.4 31.7 17 25.4 4.4 30.8
3/1 15 21.7 6.3 34.8 20 23.4 4.7 32.0 12 25.9 4.8 31.9
3/15 8 21.9 5.9 35.0 15 22.1 4.9 30.8 6 24.4 5.6 32.3
4/1 15 20.6 7.1 34.4 11 21.4 6.6 30.5 10 23.6 6.0 31.9
4/15 20 20.0 7.9 34.2 13 19.8 7.3 29.8 14 22.7 6.9 31.9
5/1 22 19.9 8.5 33.3 21 20.0 7.5 31.2 20 21.9 7.2 31.1
5/15 21 21.8 9.1 33.9 22 19.5 7.8 29.8 18 20.5 6.9 29.7
6/1 16 21.0 8.3 33.6 19 19.3 7.8 29.5 15 20.1 7.1 29.4
6/15 - - - - 16 20.0 8.0 30.0 17 20.4 7.3 30.8

1 Samples collected semi-monthly from

December through June, inclusively, during each processing season.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/10/68-RWB

Table 6. Relationship of date of packing to average Hunter Color values for commercial frozen concentrated orange
juices collected from Florida processing plants.
Hunter Color Difference Meter average values for reconstituted juices
1965-66 season 208 samples 1966-67 season 220 samples 1967-68 season 197 samples
Approx. Number Number Number
date of Rd a b of Rd a b of Rd a b
packed samples samples samples
12/1 - - - -
12/15 8 21.9 -4.8 29.8 4 25.2 -5.6 30.1 10 23.2 -5.2 28.2
1/1 18 22.9 -5.1 29.9 15 25.5 -6.0 30.4 16 23.1 -5.5 28.0
1/15 21 22.5 -5.5 30.0 23 25.0 -6.2 29.0 21 22.7 -5.5 28.6
2/1 23 23.2 -5.1 30.7 21 25.2 -6.1 28.8 21 23.1 -5.2 28.7
2/15 21 22.7 -4.6 31.4 20 24.8 -5.9 28.8 17 25.4 -6.1 27.8
3/1 15 22.1 -4.1 31.8 20 24.2 -5.2 28.9 12 25.6 -5.9 27.4
3/15 8 22.5 -4.1 32.2 15 23.2 -5.1 27.7 6 24.1 -4.7 29.0
4/1 15 21.8 -3.3 32.3 11 22.3 -3.8 28.5 10 23.3 -4.4 28.9
4/15 20 21.0 -2.7 32.2 13 20.9 -3.0 28.1 14 22.9 -3.6 29.2
5/1 22 21.3 -1.9 31.8 21 20.6 -3.1 29.1 20 22.2 -2.8 28.6
5/15 21 23.6 -1.8 32.4 22 20.7 -2.8 28.1 18 21.5 -2.8 27.9
6/1 16 21.8 -2.8 31.6 19 21.0 -2.8 28.0 15 21.0 -2.8 27.5
6/15 - - - 16 21.5 -2.8 28.2 17 21.0 -3.5 28.1
1Samples collected semi-monthly from December through June, inclusively, during each processing season.
Samples collected semi-monthly from December through June, inclusively, during each processing season.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/10/68-RWB