Group Title: Citrus Station mimeo report - Florida Citrus Experiment Station ; CES 67-11
Title: Preliminary report on freezing of grapefruit sections for loose pack
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 Material Information
Title: Preliminary report on freezing of grapefruit sections for loose pack
Series Title: Citrus Station mimeo report
Physical Description: 6 leaves : ; 28 cm.
Language: English
Creator: Fellers, P. J
Citrus Experiment Station (Lake Alfred, Fla.)
Florida Citrus Commission
Publisher: Florida Citrus Experiment Station :
Florida Citrus Commission
Place of Publication: Lake Alfred FL
Publication Date: 1966
 Subjects
Subject: Grapefruit -- Packing -- Florida   ( lcsh )
Grapefruit -- Storage -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references (leaf 6).
Statement of Responsibility: P.J. Fellers.
General Note: Caption title.
General Note: "400-10/4/66-PJF."
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Bibliographic ID: UF00072447
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 76246576

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Florida Citrus Commission and
Citrus Experiment Station CES 67-11
Lake Alfred, Florida. 400-10/4/66-PJF


Preliminary Report on Freezing of Grapefruit Sections for Loose Pack.

P. J. Fellers
Florida Citrus Commission
Lake Alfred, Florida


For all practical purposes, no loose-pack frozen grapefruit sections are
marketed today in the United States. From time to time, however, individual,
frozen, loose-pack sections do appear on the market. A Texas firm brought out
such a product in 1961 using a flash freezing process and "certain additives
(which prevent cell rupturing and improve flavor), and complicated water-spray
treatments during the freezing process" (4). An April 1966 report (5) describes
another Texas firm's loose pack of frozen, pink grapefruit sections. The sections
are being marketed in aluminum trays inserted in an opague polybag. This latest
frozen-section entry may be doomed to extinction, as have the others before it,
if a serious off-flavor problem associated with freezing of grapefruit sections
is not solved. The purpose of this paper is to describe some of the applied
research which has been directed toward the solving of this off-flavor problem.

At least four, and perhaps more, of Florida's citrus processors at one time
or another have attempted to successfully freeze grapefruit sections for a
loose-pack product. Personal communication with research personnel from some of
these companies revealed that flavor, texture and sticking together of frozen
sections were problems. However, the development of off-flavors after freezing
has been pointed out as being the main problem. Such terms as cardboard, castor
oil, citrus oxidized, and stale,have been used (1, 7) to described some of the
off-flavors which are collectively referred to as COF or citrus off-flavors.

Singleton (8) froze individual grapefruit sections in cans using three
treatments (a) no treatment other than freezing, (b) under a vacuum, and (c)
under a vacuum after an exhaust treatment. All of these packs were described
as being stale in flavor after a few months of -100F. storage. However, Singleton
did successfully freeze grapefruit sections covered with high Brix sucrose syrups
plus 0.01 or 0.02% by weight of either ethyl caffeate antioxidant or a small
amount of Sustane 3 (a Universal Oil Products Company antioxidant composed of
20% butylated hydroxyanisole, 4% citric acid, 6% propylgallate and 70% propylene
glycol). Singleton was also successful in freezing sections covered with high
Brix sucrose syrups and given various heat treatments before freezing. However,
even though they had been heated, the enzyme, peroxidase, was found to be present
in some of the frozen sections. After about five weeks of frozen storage, these
sections having active peroxidase still had a good flavor, a point in favor for
peroxidase not being responsible for the off-flavor development.

Nickerson (6) has described the use of ethyl caffeate, hydrocaffeic acid,
ethyl hydrocaffeate and similar compounds in stabilizing flavor in frozen
grapefruit. However, most of this study involved only the addition of these
antioxidants to covering syrups. It is not clear whether or not flavor was
stabilized in sections given dip treatments of the caffeate substances prior to
freezing. DeFelice and coworkers (2) in their studies on the use of caffeates
in frozen sections in syrup stated "we found grapefruit did not need the anti-
oxidant so that individual segments may or may not prove the efficacy of the
treatment".








Dougherty (3) was unable to obtain good-flavored, individual frozen grape-
fruit sections. Neither dipping or soaking sections in various solutions of
ascorbic acid nor packing sections in hermetically sealed cans under a nitrogen
atmosphere solved the off-flavor problem.

Much research has been done on off-flavor problems in frozen citrus products,
other than individual, frozen grapefruit sections. Off-flavors (COF) have been
effectively eliminated from frozen concentrated orange juice presumably by the
combination of short-time, high-temperature heat treatment and by adding sufficient
orange oil to the concentrate.

General experimental procedures. Florida grapefruit, mostly from the Winter
Haven area, was used. Fruit was used either directly after harvest or stored at
40F. until needed. In preparing grapefruit sections, fruit were peeled by hand,
placed in hot lye solution until the membranes came away easily, cooled immedi-
ately in running water, and sectionized by hand. For preparation of juice, a
household electric reamer was used. Polyethylene bags double wrapped and heat
sealed were used to package the products. Storage was at -10F. in an upright
freezer. Taste panel evaluations were made periodically by 5 to 9 screened
panelists.

Flavor changes of grapefruit juices in frozen storage. There is no question
but that frozen single-strength grapefruit juice or sections lose some of the
characteristic good, fresh grapefruit odor and taste. Just how rapidly grapefruit
loses its good flavor was shown in the following experiment. Fresh juice was
obtained from both Duncan and Marsh grapefruit, harvested December 2, 1965. Also,
enough of the same fruit of each variety was placed in 40F. storage for later use.
Some of each of the fresh juices was immediately tasted and scored by a panel. The
remainder of the juices was packaged in several polyethylene bags and frozen at
-100F. Triangular difference-preference tests were used for the frozen juice
versus fresh juice extracted from the same lots of whole fruit held in cold storage.
Results are shown in Table 1. It is remarkable that after only one day of frozen
storage, the panel was able to significantly differentiate fresh Duncan juice from
frozen juice; and similarly after five days between the fresh and frozen Marsh
juices. Initially, the Marsh juice was more sour and bitter than the Duncan juice;
a fact which may have masked any small flavor change in the Marsh juice. After
each of the storage periods the fresh juices always rated better than those that
were frozen. Data collected from this study suggest that a very rapid trans-
formation of flavor compounds occurs in the frozen juices of grapefruit harvested
in early December.

Effect of antioxidants in frozen grapefruit juices. Since the off-flavor
development in frozen grapefruit was thought to be oxidative in nature, several
antioxidants were added to Duncan grapefruit juice to be frozen in polyethylene
bags. Ease of treatment preparation, and desire for product uniformity
warranted use of juice rather than sections for this particular study. It was
well controlled in that the same five persons judged the samples at each tasting
over a period of six months. Table 2 shows the taste panel data. The panel was
consistent in judging the juice treated with 0.0075% Tenox 2 (Eastman Chemical
Products, Co.; 20% butylated hydroxyanisole, 6% propylgallate, 4% citric acid,
and 70% propylene glycol) as having a "Fair-6" to a "good-7" flavor over the six
months of frozen storage. For four of the five tasting, the juice containing
the Tenox 2 rated significantly better than either the control juice or that with


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










alpha-tocopherol. Taste panel comments on the control and alpha-tocopherol
treated juices after six months were nearly identical: nondescript off-flavor
(two panelists) and COF (two panelists). Whenthe juice was treated with 0.02%
ethyl hydrocaffeate, a consistent decrease from its initial good flavor occurred
throughout the first four months, but with some improvement in flavor after six
months storage.

Tenox 2, at a concentration of 0.0075% by weight, and to a lesser extent
0.02% ethyl hydrocaffeate, acts to a moderate degree as a flavor preserving
agent in frozen grapefruit juice for at least six months of frozen storage.
Triangular difference-preference tests showed 0.0075% Tenox 2 as being the maxi-
mum amount which could be used in grapefruit products without imparting an
inherent offensive odor and taste to the product.

Effect of aeration and antioxidant. Olsen and coworkers (7) were able to
produce COF in frozen citrus concentrates by incorporating excessive amounts of
air into such products before freezing, by using a Waring Blendor. In this
study, such "forced" oxidation of Marsh grapefruit juice was also accomplished
by aerating it in a Waring blendor; Tenox 2 was also added to these samples.
The juices were then filled into polyethylene bags, frozen, and stored at -100F.
Taste panel results (Table 3) indicate that the flavor of the juice, containing
0.0075% of Tenox 2 and blended for 2 min., was significantly poorer than that in
the juices treated in different ways, including even the juice with Tenox 2
which was blended for 6 min. It might be theorized that the more severe
aeration and physical mixing resulted in eliminating or reducing the amount of
certain off-flavor substances which developed after 2 min. of blending. This
theory would be consistent with at least 2 reports (1, 7) stating that certain
frozen citrus products having COF have reverted back to their normal acceptable
flavor after being in frozen storage for some time.

The flavor differences resulting from the different treatments were not
nearly as great as anticipated. All of the grapefruit juices, including the
control, lost their good fresh flavor in one and a half months. Only a slight
further loss in flavor occurred during frozen storage for 8 months. Tenox 2
failed to prevent off-flavor development in juice which was aerated. However,
in agreement with results reported in the preceding study, addition of Tenox 2 to
nonaerated juice resulted in somewhat better flavor than that of the other stored
juices.

Effect of ethylenediaminetetraacetic acid (EDTA) on the flavor quality of
frozen grapefruit juice. EDTA is a chelating agent which acts by "tying up"
traces of heavy metal ions, especially copper and iron ions, thus rendering them
useless in certain catalytic oxidative reactions. If such a reaction was
responsible for off-flavor development in frozen grapefruit juice, then it was
hoped that addition of EDTA would stop the reactionss. Grapefruit juice, a
mixture of Duncan and Marsh juices, was used in this study. EDTA was added to
the juice alone and with antioxidants as shown in Table 4. Juice was packed in
polyethylene bags, 200 ml. per bag and three replications per treatment, and
placed in frozen storage. At all tasting and after nearly a year in frozen
storage, the grapefruit juices treated with 0.0075 or 0.02% by weight EDTA
possessed significantly better flavor, ranging from a "fair-6" to a "good-7",


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








than the control which was rated a "poor-4" to a "fair-5". The latter juice was
characterized by most taste panel members as having COF. The juices to which
both EDTA and antioxidants were added showed no significant difference in flavor,
from those containing only EDTA.

To determine if EDTA possessed a flavor of its own in the concentrations
used, triangular difference-preference tests were run. EDTA could not be detected
in fresh grapefruit juice in a concentration of 0.0075% by weight (75 ppm), but
was detectable at 0.02% (200 ppm) concentration. The EDTA-produced flavor was
described by the panelists as being unoffensive.

Effect of variety and method of freezing on flavor of frozen grapefruit
sections. Marsh, Ruby Red, and Duncan grapefruit, harvested February 9, 1965,
were sectionized by hand and frozen in polyethylene bags at both -100F. and
-3200F,, the latter being the temperature of liquid nitrogen. After 7 months of
-100F. storage, the sections were thawed and evaluated. The average flavor
scores for the panel are given in Table 5. All sections lost much of the
characteristic good flavor associated with fresh fruit, and five of the six
treatments showed off-flavors. No significant difference in flavor was found
between freezing methods. However, the flavor of Ruby Red sections, frozen at
-100F., were found significantly (at the 5% level) worse than that of the Marsh
or Duncan sections frozen at the same temperature. The trend of the average
panel scores, for both freezing methods was that frozen sections made from the
Duncan variety rated best, followed by Marsh, and then Ruby Red. These results,
in general,agree with most reports as to the flavor quality of fresh or pro-
cessed grapefruit, especially in that seeded grapefruit usually possess better
flavor than seedless fruit.

Three sidelights should be mentioned in regard to this study: (a) A method
was developed for freezing individual sections in liquid nitrogen without the
sections becoming fragile and breaking into individual juice sacs. In this
method the sections were only partially frozen in the liquid nitrogen with
freezing being completed by conventional means; (b) Drip loss on thawing of
sections frozen under liquid nitrogen was found to be significantly less than
that for sections frozen at -10F.; (c) Texture in thawed sections which were
frozen in liquid nitrogen was, in general, better than that in sections frozen
at -100F.

Effect of various factors on the quality of frozen Duncan grapefruit
sections. Duncan sections polyethylene bag packed and frozen were treated in
several ways as indicated in Table 6. Sections which were dipped were so treated
before packaging and freezing. To insure homogeniety of each sample at the time
for evaluation, the sections were thawed and placed in a Waring blendor for two
seconds; then the large pulp was sieved out, and the resultant juice used for
the taste panel sample. As shown in Table 6, the flavor quality of all samples
decreased in frozen storage for four months, after which a general leveling off
in the "fair" flavor range occurred. Unlike the studies in which grapefruit
juice lost good flavor rapidly in frozen storage, all of these packs of sections
still rated "good" after two months of storage. After seven months, the panel
as a whole, judged all samples as having "fair" flavor; however, some individual
panelists after both four and seven months found some of the samples unacceptable
because of "poor" flavor. If the results for the five panelists, who tasted
every time these samples were judged, are segregated out, strong trends existed
for those sections dipped in 0.25% ethyl hydrocaffeate solution and the
combination 0.05% ethyl hydrocaffeate and 0.5% "Sucaryl" solution. These two
treatments indicated better flavor than those which were treated differently.
Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 400-10/4/66-PJF









Also, the control sample stored at -100F. had the poorest flavor.

Effect of various factors on the quality of frozen Marsh grapefruit sections.
Samples for this study were prepared as in the preceding study, except that Marsh
grapefruit sections with some different treatments were also packed. Table 7
shows results for the various treatments. Flavor quality in all of the samples
remained more or less constant in the "fair" range through 10 months of frozen
storage. However, there was a loss from the initial "good" flavor of the fresh
sections. The sample, which had no treatment other than freezing at -10F.,
was judged acceptable by the panel as a whole, although there were a few individ-
ual panelists who found some of the samples unacceptable because of "poor" flavor.
Water glazing has been used for years with good success in the fisheries industry
to preserve flavor and texture quality in frozen fish. However, in this study
water glazing was found nt successful in preserving frozen citrus flavor.

Effect of EDTA alone and in combination with other substances on the quality
of frozen Foster Pink grapefruit sections. Sections were prepared as previously
described. Results reported in Table 8 indicate the several treatments and the
taste panel data for these sections stored at -10F. over an eight-month storage
period. As in most of the other studies, flavor loss was marked in all samples
after only one and one-half months of frozen storage, decreasing from "good" to
"fair" in that time. There were no significant differences between the seven
treatments at the 1.5, 4, and 6-month evaluations. However, after eight months
the control pack and the sections dipped in 0.02% EDTA plus 0.02% coldpressed
grapefruit oil solution were significantly poorer in flavor than that of the
other packs. It should also be noted that the 0.03% EDTA-treated sections con-
sistently rated at least a "fair-6" at all tasting, the only treatment to
achieve this high level.

Effect of alginate dips on the quality of frozen Duncan grapefruit sections.
Data for the last study to be discussed in this report are presented in Table 9.
Sections were dipped both as fresh and as frozen sections before being packed and
placed in frozen storage. As may be seen from Table 9, no substances used in
solution as dips were able to arrest loss of good grapefruit flavor and off-flavor
development in the frozen sections. However, the sections dipped in 1.5% Kelgin
LV solution before freezing had significantly better taste than did the sections
dipped in the same concentration of Kelgin LV after the sections were frozen.
This same trend also existed for the other two concentrations of Kelgin LV.

An interesting side light to this study is that the panel rated fresh
grapefruit taste better than the odor on identical samples in all instances.

The preceding results and the data collected from other studies suggest that
the main cause of the off-flavors experienced in frozen grapefruit sections
originates within the juice sacs and not necessarily on the surface of the
sections. The freezing in some unexplained way creates favorable conditions for
off-flavor development. Exactly what phenomena and reactions are involved are
not known for sure. What does appear to be true, however, is that the cryobiology
involved in freezing and storage of individual grapefruit sections is complex.

Present and future status. Several further areas of study are either under-
way or being planned. For example, the use of heat as a blanch treatment using
live steam, hot water, and microwave energy are under study. Soaking treatments


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









in which grapefruit sections are held prior to freezing in various solutions con-
taining compounds such as sugars, artificial sweeteners, EDTA, and antioxidants
are being investigated. Grapefruit sections coated with low viscosity carboxy-
methylcellulose solutions are currently being evaluated, as well as vacuum packs
in oxygen impermeable films. Finally, some basic research methods employing
microscopic examination of fresh, freezing, and frozen juice sacs in conjunction
with histological techniques is being planned; as is also the use of gas chro-
matography and similar techniques to try to isolate and identify the COF pro-
ducing compounds.


Literature Cited

1. Blair, J. S., Edith M. Godar, H. G. Reinke, and J. R. Marshall. The
"COF effect" in frozen citrus products. 11, 61-68 (1957).

2. DeFelice, D. Personal communication. Research Center, General Foods
Corporation, Tarrytown, N. Y. Jan. 18, 1965.

3. Dougherty, M. H. Utilization of grapefruit. Fla. Agr. Exp. Sta. Ann.
Rept. 239 (1964).

4. Flash-frozen citrus sections. Florida Grower and Rancher. 69, 9 and
16 (1961).

5. Grapefruit in aluminum trays. Quick Frozen Foods, 28, 99 (1966).

6. Nickerson, J. T. R. Stabilization of frozen grapefruit. U.S. Patent
No. 2,437,752 issued March 16, 1948. 3p.

7. Olsen, R. W., E. L. Moore, F. W. Wenzel and R. L. Huggart. Oxidized
flavors in frozen citrus concentrates. Citrus Expt. Sta. Mimeo Rept. 56-1.
(1955).

8. Singleton, G. Some recent work on citrus sections. Proc. Fla. State
Hort. Soc. 72, 263-267 (1959).

Acknowledgments

The suggestions of Mr. M. H. Dougherty, Dr. F. W. Wenzel and Dr. L. G.
MacDowell was appreciated. The author wishes to thank the Dow Chemical Co.,
Midland, Mich., Eastman Chemical Products, Co., Kingsport, Tenn., R. W. Greeff
and Co., Inc., New York, N. Y., and the Kelco Co., Clark, N. J. for supplying
samples used in this investigation.









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













Table 1. Flavor comparison of fresh and frozen grapefruit juices using triangular difference -
preference tests.
Significantly Significantly
different at different at Av. panel scores1 for treatments
Grapefruit Days in the 5% level the 1% level
variety -100F. storage (highly significant) Fresh Frozen

Duncan 0 - 7.6 -
1 Yes No 6.6 6.1
5 Yes Yes 6.8 4.8
34 Yes Yes 7.0 4.4

Marsh 0 - 7.0 -
1 No No 5.7 5.4
5 Yes No 7.1 5.5
34 Yes Yes 6.3 4.7
1 Taste panel score values are as follows: 10 = excellent; 9 = very good; 8-7 = good; 6-5.= fair; 4-3 = poor;
2 = very poor; and 1 = unpalatable. In the instructions to the panelists, an individual rating less than
"5" further indicated that the panelist would not repurchase that particular product.


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











Table 2. Effect of antioxidants on the quality of frozen Duncan grapefruit juice as evaluated periodically by the
same five tasters.
Individual taste panel scoresI
No treatment 0.005% alpha-tocopherol 0.02% ethyl hydrocaffeate 0.0075% Tenox 2 2
Individual Months in frozen storage
tasters 1 2 3 4 6 1 2 3 4 6 1 2 3 4 6 1 2 3 4 6
A 7 7 5 6 5 6 6 6 6 6 6 7 7 4 8 6 8 7 7 7
B 5 5 4 5 5 4 5 4 5 5 8 7 6 4 6 7 8 7 7 7
C 6 8 7 7 4 7 8 6 6 4 8 5 5 5 6 6 6 7 7 6
D 4 3 3 3 3 6 2 2 2 4 6 6 3 4 5 4 6 4 4 4
E 4 4 4 4 3 3 3 4 4 3 5 6 5 6 5 5 6 6 5 6

Av. panel
scores 5.2 5.4 4.6 5.0 4.0 5.2 4.8 4.4 4.6 4.7 6.6 6.2 5.2 4.6 6.0 5.6 6.8 6.2 6.0 6.0


Av. panel
scores for
all tasting
combined


A


5.7


1
Refer to Table 1, footnote 1, for an explanation of score values.

2 Tenox 2 (Eastman Chemical Products, Inc., Kingsport, Tenn.) is composed of 20% butylated hydroxyanisole, 6% propyl
gallate, 4% citric acid, and 70% propylene glycol.


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


. ..R 57






Table 3. Effect of forced oxidation and/or Tenox 2 antioxidant on
uicire flav


frozen grapefruit


Treatment Average flavor scores1 for panel Av. scores each
% by weight of Min. in a Months in frozen storage treatment
Tenox 2 in juice Waring blendor Fresh 1.5 3 5 8 during storage
0 0 8 5.7 4.5 4.7 5.3 5.1
0.0075 0 8 6.1 5.5 5.3 5.1 5.5
0.0075 2 8 4.8 4.5 4.3 4.3 4.5
0.0075 6 8 5.3 5.3 5.0 4.6 5.1
Refer to Table 1, footnote 1, for an explanation of score values.


Table 4. Effect of EDTA alone and in combination with antioxidants on
preserving flavor quality in frozen grapefruit juice.
Average flavor scores1 for panel
Months in frozen storage
Treatment Fresh 8.5 9.5 11.5
No treatment (other than freezing) 8 4.9 4.2 4.7
0.0075% Versene CA2 added 8 6.1 6.8 6.4
0.02% Versene CA added 8 5.9 6.3 7.0
0.01% Versene CA plus 0.02% 8 5.9 5.5 6.0
ethyl hydrocaffeate added
0.01% Versene CA plus 8 5.4 6.5 6.3
0.0035% Sustane E3 added
1 Refer to Table 1, footnote 1, for an explanation of score values.
2 Versene CA is Dow Chemical Company's experimental food grade of calcium
disodium EDTA.
3 Sustane E (Universal Oil Products) is composed of 50% butylated hydroxy-
anisole + 50% polysorbate 80.

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










Table 5. Flavor quality of sections made from three grapefruit varieties
frozen by two methods and stored at -100F. for seven months.
Av. taste panel scores1 and comments2 for treatments
Frozen at -100F. Frozen in liquid nitrogen
Duncan Marsh Ruby Red Duncan Marsh Ruby Red
6.6 6.0 4.2 6.4 5.2 4.8
slight COF bland flavor; bland flavor; nondescript nondescript
slight COF slight COF off-flavor off-flavor
Refer to Table 1, footnote 1, for an explanation of score values.

2 Comments were made by at least two or more of the panel members.








Table 6. Effect of several factors on flavor quality of frozen Duncan
grapefruit sections.


Treatment
Frozen at -100F.
Frozen by immersion in liquid
nitrogen
Frozen by dry ice
Dip in 0.005% alpha-tocopherol
soln. before freezing
Dip in 0.01% Tenox 2 soln.
before freezing
Dip in 0.25% ethyl hydrocaffeate
soln. before freezing
Dip in 0.05% ethyl hydrocaffeate +
0.05% sucaryl soln. before freezing


Refer to Table 1, footnote 1, for an
Refer to Table 1, footnote 1, for an


Average taste panel scores1 for treatments
Months in frozen storage
2 4 7


5.8
5.5


5.5
5.7


6.6
7.0


7.3
6.9


7.4


7.0


6.7


6.0


6.2


explanation of score values.


2 Initial flavor quality of the Duncan grapefruit rated a "good" 8.








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


--





Table 7. Effect of several factors on flavor preservation of frozen Marsh grapefruit sections.
Taste panel scores1 for treatments
Months in No treatment other Frozen in Washed prior Frozen sections 5 Min. dip in 0.04%
frozen than freezing liquid nitrogen to freezing water glazed ethyl hydrocaffeate
storage at -100F. soln. before freezing
Fresh 7.5 7.5 7.5 7.5 7.5
2 5.8 5.5 5.5 6.0 5.5
4 6.2 4.8 5.8 Missing 5.2
6 5.8 7.0 4.8 5.0 6.2
10 6.2 5.3 5.5 5.7 5.3
Refer to Table 1, footnote 1, for an explanation of score values.


Table 8. Flavor quality of Foster Pink grapefruit sections treated in
several ways prior to freezing.
Average flavor scores1,2 for panel
Months in frozen storage
Treatment Fresh 1.5 4 6 8
No treatment (other than freezing) 8.0 5.6 6.0 5.1 4.7
Dip in 0.01% EDTA3 soln. 8.0 5.8 5.6 5.9 6.0
Dip in 0.03% EDTA soln. 8.0 6.0 6.1 6.4 6.0
Dip in 0.02% EDTA + 0.03% ethyl
hydrocaffeate soln. 8.0 5.8 5.2 5.7 5.7
Dip in 0.02% EDTA + 0.0035%
Sustane E3 soln. 8.0 5.4 5.2 6.6 6.1
Dip in 0.02% EDTA + 0.01% alpha-
tocopherol soln. 8.0 5.4 6.1 6.4 5.7
Dip in 0.02% EDTA + 0.02% cold-
pressed grapefruit oil soln. 8.0 5.2 5.6 5.7 4.8
1 Refer to Table 1, footnote 1, for an explanation of score values.
2 EDTA = Calciumsodium chelate of ethylenediaminetetraacetic acid; Sustane E =
50% butylated hydroxyanisole + 50% polysorbate 80 (Universal Oil Products
Company).


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











Table 9. Taste panel results comparing fresh Duncan grapefruit sections with
sections having undergone different treatments and kept in frozen storage for about
two months.


Treatments
Fresh
No treatment (other than frozen for 2 months)
Dipped in 0.5% Kelgin LV3 solution before freezing
Dipped in 1.0% Kelgin LV solution before freezing
Dipped in 1.5% Kelgin LV solution before freezing


Average taste
panel scores1,2
Odor Taste
7.5 8,7
5.0 5,5
5.3 5.8
5.2 5,3
5.2 6.2


Fresh
No treatment (other than
Dipped in 0.5% Kelgin LV
Dipped in 1.0% Kelgin LV
Dipped in 1.5% Kelgin LV


frozen for 2 months)
solution after freezing
solution after freezing
solution after freezing


Fresh
No treatment (other than frozen for 2 months)
Dipped in 0.5% Keltose4 solution before freezing
Dipped in 1.0% Keltose solution before freezing

Fresh
No treatment (other than frozen for 2 months)
Dipped in 0.5% Keltose solution after freezing
Dipped in 1.0% Keltose solution after freezing
Dipped in 0.75% 7 HOP-1 carboxymethylcellulose5
solution after freezing


7.3
4.7
4.2
4.7
5.2

7.5
4.3
4.5
4.7

8.0
5.3
5.0
5.0
5.3


At least six panelists participated in tasting each treatment.

2 Refer to Table 1, Footnote 1, for an explanation of score values.

3 Product of the Kelco Company, Clark, N. J.

Product of the Kelco Company, Clark, N. J.

5 Product of the Hercules Powder Company, Wilmington 99, Del.












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


8.3
4.7
5.2
4.2
4.3

8.7
4.8
5.2
4.2

8.7
5.3
4.7
5.5
5.2




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