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Summary of citrus processing and by-products research projects.
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SUMMARY OF CITRUS PROCESSING AND BY-PRODUCTS RESEARCH PROJECTS
Year Ending June 30, 1960

Florida Citrus Experiment Station and Florida Citrus Commission
Lake Alfred, Florida


MICROBIOLOGY OF FROZEN CONCENTRATED CITRUS JUICES

State Project 550 Roger Patrick and E. C. Hill


Identification of Microorganisms in Citrus Concentrates. Forty samples of
commercial frozen orange concentrate were examined during December 1958 and
January 1959. In the first group of 19 samples, 8 samples contained strepto-
cocci of which 6 gave the presumptive test and 4 the confirmed test for entero-
cocci-like organisms; no lactose fermenting bacteria were found. The second
group of 21 samples showed all samples contaminated with streptococci of which
15 gave the presumptive test and 4 the confirmed test for enterococci-like
organisms; two samples contained lactose fermenting bacteria.

This project is being terminated with this report.


FLORIDA CITRUS OILS

State Project 607 J. W. Kesterson and R. Hendrickson


Work has been initiated to determine how the chemical and physical compo-
sition of Valencia orange and Marsh grapefruit oils vary with maturity. The
production of oils in this study began when small immature fruit were about
1 in. in diameter and continued at 6-week intervals thereafter until the fruit
reached maturity.

The grapefruit oils have been submitted to a panel of experts for organo-
leptic evaluation. A progressive difference in odor and flavor was observed as
the fruit became more mature. Oil made from immature fruit showed decided off
notes. Oil produced from mature fruit gave a full rich body oil with a distinct
grapefruit character. Infrared absorption curves were identical except for
increased absorption areas at 12.72 and 13.15 u as the fruit progressed in
maturity. The physical and chemical characteristics and infrared data were
found to correlate with flavor evaluation data. On the basis of these findings
the selection of coldpressed grapefruit oil for maximum flavor could be made by
choosing the oil having the greatest absorption at 12.72 and 13.15 u.

Coldpressed Murcott oils expressed by the FMC In-Line extractor have been
evaluated. The chemical and physical properties, organoleptic, infrared, and
gas chromatographic data show these oils to have properties most similar to
those for tangerine oil.

Citrus oils produced by the screw press, Pipkin roll, Sfumatrici, FMC In-Line
extractor, and Fraser-Brace grater were evaluated for quality during the 1959-60
season. The physiochemical properties of these oils were considered normal.


Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred Florida.
987 9/21/60 FWW





-2-


STORAGE STUDIES ON CONCENTRATED CITRUS JUICES

State Project 611 E. L. Moore, A. H. Rouse, and C. D. Atkins

Storage at -80 and 100 F has been terminated after 412 days for the packs of
420 Brix Valencia orange concentrates prepared from both uncut and cut juices
(Ann. Rep. 1958, p. 210; 1959, p. 215), that had been prepared to investigate
further the relative effect of heating either the single-strength juice prior to
evaporation or 2-, 3-, and 4-fold concentrates withdrawn during the evaporation
of unheated juice and subsequently heat treated. After storage for 412 days at
these 2 temperatures, no significant clarification had occurred in the concentrates.

Packs of 420 Brix Pineapple orange concentrates were prepared for the purpose
of obtaining a stabilized product with increased "cloud" by controlling mainly the
quantity of water-insoluble solids with the use of a centrifuge (Westfalia Sepa-
rator Model SAOOH 205). Finisher juice was centrifuged to obtain overflow (low
pulp) and underflow (high pulp) juices. Combinations of evaporator and cutback
juices were made from the overflow, underflow, and finisher juices. Where juices
or mixtures of juices were stabilized, temperatures of 1650 and 1950 F were used;
the control packs received no heat treatment. By varying these factors, the
cloud, pulp, pectinesterase activity, water-insoluble solids, and water-soluble
pectin of the concentrates were controlled. Storage studies on these packs indi-
cated no practical way for including large amounts of water-insoluble solids in
these products without high heat treatment to prevent stability problems.

This project is being terminated with this report.


RECOVERY AND UTILIZATION OF NARINGIN

State Project 622 J. W. Kesterson and R. Hendrickson

For convenience and brevity, work on this project is reported under Citrus
Station Project 646 Recovery and Utilization of Hesperidin.


RECOVERY AND UTILIZATION OF HESPERIDIN

State Project 646 R. Hendrickson and J. W. Kesterson

The basic intent of this project is an exploratory examination into the
profitable recovery of hesperidin from both waste peel and whole fruit of the
important varieties of citrus.

An attempt to resolve the accrued advantages of recovering hesperidin from
immature whole fruit rather than surplus ripe fruit was initiated. Hesperidin was
extracted at different pH levels from a portion of the total crop of fruit stripped
from Valencia trees periodically throughout the season from the time fruit were
1 in. in size to full maturity. Variations in yield and purity of recovered
hesperidin were compared against picking date and pH extracting conditions on a
per-ton-of-fruit, per-ton-of-peel, per-tree, and per-acre basis.


Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
987 a 9/21/60- FWW





-3-


The most immature fruit yielded hesperidin of highest purity, under best
conditions affording a product of 84% purity. The highest extracting pH, 11.3,
was noticeably superior in extracting hesperidin although less critical with
fruit of greater maturity. Maximum yield of hesperidin on a per-ton-of-fruit
basis occurred when the most immature fruit was processed. Maximum quantity of
hesperidin on a per-acre-of-fruit basis was markedly superior with fruit having
an equatorial diameter of 2.2 in. whereupon a yield of 77 lb. of pure hesperidin
was obtained; smaller and larger sizes produced lower yields. The percentage of
hesperidin in Valencia oranges decreased logarithmically as fruit size increased.

A similar study on the extraction of naringin from Marsh grapefruit gave
somewhat similar results with the exception that plain water could be used as
an extractant for immature fruit with some loss in yield, but with the added
advantage of having the peel in ideal condition for the later recovery of pectin.


CLARIFICATION AND GELATION IN CONCENTRATED CITRUS JUICES

State Project 649 C. D. Atkins, A. H. Rouse, and E. L. Moore

Clarification, gelatin, and related characteristics were determined for
197 commercial samples of mid- and late season frozen orange concentrates pro-
cessed during the 1958-59 season. These characteristics were compared with
those for similar products collected during the seasons of 1953-54, 1954-55,
1956-57, and 1957-58. Less than 1% of the concentrates from the 5 seasons showed
initially definite or extreme cloud loss and the degree of gelation found initially
in these samples was not considered to be of importance to consumers. The sta-
bility of the concentrates during storage at either 72 or 96 hours at 400 F
improved over the 5-year period with few of the 1958-59 samples showing definite
or extreme clarification or forming undesirable gels.

Pulp content in the 1958-59 midseason juices averaged 11.2% and for the late
season samples 9.9%, which represented a slight decrease over the higher pulp
contents reported in the 4 previous seasons. Water-insoluble solids for the
combined mid- and late season samples averaged 163 mg/100 g for the 1958-59 season
in comparison with 164 mg/100 g, the average value for the 4 seasons during which
this test was used. Pectinesterase activity decreased over the 5-year period with
an average for the 1958-59 season of 2.4 units and 11.2, 8.1, 5.2, and 2.8 units
for the previous seasons.

Pectin in the reconstituted centrifuged juices for the 5 seasons was 37.9,
35.4, 41.4, 41.3, and 45.4 mg/100 g, respectively, indicating that slightly more
water-soluble pectin was present in the 1958-59 samples.

Flavonoids, expressed as hesperidin, averaged 82.8 mg/100 ml in the mid-
season samples and 75.1 mg/100 ml in the late season samples for the 1958-59
season, with no general trends indicated over the 5 years.

This project is being terminated with this report.



Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
987 b 9/21/60 FWW








CONVERSION OF CITRUS TERPENES TO USEFUL CHEMICAL COMPOUNDS

State Project 817 W. F. Newhall

The synthesis of new and more economically profitable by-products from
citrus d-limonene has been continued. Three new, unsaturated amino alcohols
(2-amino, 2-methylamino, and 2-dimethylamino-8(10)-p-menthen-l-ol) have been
prepared from d-limonene in 70% yield. These amino alcohols are the unsatu-
rated analogues of those reported previously (Ann. Rep. 1959, p. 226).

The 3 unsaturated amino alcohols and their saturated analogues have been
converted to water soluble soaps by reaction with fatty acids such as oleic
acid. The tertiary amino alcohol soaps had the best foaming and wetting
characteristics.

The benzoate ester of 2-dimethylamino-8(10)-p-menthen-l-ol has been prepared
as a possible local anesthetic. A new 2-aminooxazoline of possible use as a
central nervous system stimulant has been prepared by reaction of cis-2-amino-l-
p-menthanol with cyanogen bromide.

Tests have been conducted in cooperation with Dr. R. Patrick to evaluate
these 6 limonene amino alcohols as decay control agents for fresh citrus fruit
and as antimildew agents for cotton fabric. These compounds are not consistent
fresh fruit fungicides; however, both series of tests indicated that unsaturation
increased fungicidal potency and that the tertiary amino alcohols were the best
fungicides. The tertiary amino alcohols and their oleate soaps showed antimildew
properties comparable to salicylanilide at dilutions of 1 to 10,000.

In preliminary tests, Dr. E. P. DuCharme has found that the burrowing nema-
tode is killed by direct contact with dilutions of 1 to 1,000 of all 6 amino
alcohols.


PRODUCTION OF GLYCEROL AND GLYCOLS FROM CITRUS FRUIT WASTES

State Project 921 Roger Patrick and S. K. Long

Further work on the 2,3-butylene glycol fermentation by 2 Aerobacter species
has led to modification of earlier methods. The buffer, CaCO3, was found to re-
tard the rate of fermentation and was replaced by periodic determination and
adjustment of pH with 10 N NaOH. Similarly, increased efficiency of fermentation
was obtained using 200 Brix concentrated press water or diluted molasses (21-22%
sugar) instead of press water. With these substrates, maximum glycol production
of 4.45-4.9% (w/v) was obtained in 24 hours with residual sugar of only 1-2%.

Pre-pilot plant scale production of levo-2,3-butylene glycol by Bacillus
polvmvxa, NRRL-510, has been accomplished using 200 Brix molasses as substrate.
Added nitrogen was also required for this organism. A survey of various nitrogen-
ous compounds revealed that urea, 0.4%, or equivalent quantities of urea-contain-
ing fertilizer, gave the highest yields of glycol (4.2-4.4%) in 48 hours. Use of
CaCO3 as a buffer was detrimental to this fermentation also and reduced yields by
50%. No decrease in glycol production was observed when NaOH was used for pH
control. The optimum temperature for the fermentation was 30 C.
Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
987 c 9/21/60 FWW






-5-


The previous method of recovery of glycol from the fermentation beer, i.e.,
distillation in vacuo, was less satisfactory than a continuous multistage liquid-
liquid extraction using ethyl acetate as the solvent. Recovery of 60-90% of the
glycol content of the beer has been obtained by this method with little loss of
solvent,


PECTIN AND PECTIC ENZYMES IN THE FRUIT AND PROCESSED PRODUCTS OF CITRUS

State Project 1019 A. H. Rouse, C. D. Atkins, and E. L. Moore

Basic research was begun on the distribution of the pectic fractions and
pectinesterase activity in the component parts of citrus fruit during ripening
to better understand their roles in processing. Valencia oranges were picked
the first of each month (November 1959 through June 1960) from the same trees,
washed, dried, and then separated by hand into peel, membrane, juice sacs, seeds,
and juice. Highest pectinesterase activity was found in the juice sacs which
ranged from a low of 10.9 units in November to 98.5 units in June; the least
activity was found in juice, being only 0.4 units or less. Peel and membrane
contained similar amounts of activity, the former ranging from 7.5 to 16.2
units and the latter from 7.2 to 20.2 units. Peak activity was reached in June.
Seeds varied from 1.0 to 2.5 units of pectinesterase. On the basis of percent-
age by weight of both the whole orange and of the pectin as determined in the
component parts, the peel contained the greatest quantities of water- and
ammonium oxalate-soluble pectins, as well as the most total pectin. The seeds
and juice contained the least amount of total pectin.

During the ripening of the fruit, water-soluble pectin in the component
parts remained constant or increased very slightly, the ammonium oxalate-soluble
fraction definitely increased, and sodium hydroxide-soluble or protopectin greatly
decreased in the peel, membrane, juice sacs, and seeds. Total pectin decreased
in peel, membrane, and juice sacs during the 8-month period by 31.5%, 41.5%, and
26.6%, respectively. The amount of pectin in the relatively pulp free juice was
very small throughout the ripening months.


PRODUCTION OF ACTIVATED CITRUS SLUDGE

State Project M. H. Dougherty

A project was started, using a new type of aeration unit, to determine the
efficiency with which activated citrus sludge can be produced in treating citrus
waste waters by the activated sludge process. The new unit is a pilot plant
model "Cavitator"1. It consists of a 20-gal. plastic tank with a stainf~ ss
steel lid. Attached to the lid is a draft tube and a rotor mounted on c hollow
shaft, all of which are made of stainless steel. Rotation of the rotor causes
air to be sucked down the hollow shaft and become dispersed in the liquid con-
tents. Instantaneous mixing of the liquid is also produced by the rotor action.
Large scale units are available and are being used commercially in the treatment
of domestic sewage and other industrial wastes by the activated sludge process.

1 Registered trademark of Yeomans Brothers Company, manufacturer.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
9F7 d /- 4/ ( -0 7






-6-


An activated sludge culture was established in the pilot plant unit by
aerating an artificial citrus waste consisting of orange juice diluted with
water to approximately 0.250% total solids. Inorganic nutrients in the form
of sodium nitrate and trisodium phosphate were added to the waste at the rate
of 25 ppm nitrogen and 25 ppm phosphate. The volume of air injected into the
aerator was 0.614 cfm. The quantity of simulated citrus waste waters treated
under these conditions was increased gradually from 10 to 40 gal./day. At the
40 gal./day rate, the organic solids loading on the aerator was 0.290 lb./cu.
ft. of aeration tank/day. This loading is 30% more than was ever attained
during previous investigations using a laboratory apparatus in which the aera-
tion rate was 3 times that used in the Cavitator. In spite of this fact, the
degree of treatment accomplished by the system was excellent.


VOLATILE FLAVOR COMPONENTS IN CITRUS JUICES AND PROCESSED CITRUS PRODUCTS

State Project R. W. Wolford and J. A. Attaway

Investigations relative to the natural flavor of orange juice has been con-
cerned with (1) installation and application of additional gas chromatographic
equipment, (2) development and standardization of procedures for its use, (3)
isolation and identification of individual flavor components in orange essence;
also, (4) supplying of technical assistance to the developers of a commercial
citrus essence recovery system.

Application of a new technique, temperature programmed gas chromatography,
has provided data to indicate the presence of at least 40 volatile components
in recovered orange essence. In some cases resolution was sufficient to pro-
vide pure fractions. Two techniques employed in recovering fractions from the
gas chromatograph were condensation in cold traps and derivative formation by
reacting the eluate vapors with appropriate chemicals using a bubbler system.
Infrared analyses have been made on recovered fractions and on 2,4-dinitrophenyl-
hydrazones of eluted carbonyl compounds. In the latter case, the KBr technique
using the recrystallized 2,4-DNPH derivatives has served to characterize some
of these compounds and differentiate between aldehydes and ketones in some
derivatives. At least 8 of the totally resolved components from the orange
essence, separated on the temperature programmed instrument, gave positive
tests for carbonyls.

The gas chromatographic technique in conjunction with paper partition
chromatography and other qualitative techniques has furnished partial or com-
plete identification of the following compounds in recovered orange essence:
acetaldehyde, hexanal, hexenal, octanal, linalool, citral, carvone, and ethanol.
Beta-myrcene and d-limonene were identified in the oil separated from the es-
sence by centrifugation,


OTHER PROCESSING AND BY-PRODUCTS RESEARCH

Recovery of Fruit Solids from Orange Pulp. Water extraction of fruit
solids from or-ge pulp was introduced in 1958 by some commercial plants in
Florida as an additional process in the production of frozen orange concentrate.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
987 e 9/21/60 FWW











TABLE Comparison of Characteristics of Commercial
Orange Pulp with Those of Orange Juice.


Water Extracts of


Characteristic


Ranges in
Water Extracts *


Mid


Late


Ranges of
Orange Juices **
Mid Late


Acid, as citric %
Brix/acid ratio
Ascorbic acid mg/100 ml
Flavonoids, as hesperidin mg/100 ml
Pulp % by volume
Water-insoluble solids mg/100 g
Pectinesterase-(PE.u.)g soluble solids X 1000
Total pectin mg/100 g
Water-soluble pectin
Ammonium oxalate-soluble pectin
Sodium hydroxide-soluble pectin


SValues calculated to 120 Erix basis for comparison purposes. Ranges
water extracts were 4.00 to 8.60 for midseason and 6.10 to 8.00 for late


in Brix values for
season samples.


Range of values in orange juices obtained from some plants when water extracts were
collected. Ranges in Brix values for juices were 11.20 to 13.60 for midseason and 10.70
to 12.40 for late season samples.


Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
987 i 9/21/60 FWW


.73-1.08
11- 16
48- 61
165-237
9- 37
1-377
5- 74
116-335
86-234
0- 44
0- 76


.63-.75
16- 19
35- 46
164-245
6- 53
1-546
4- 94
99-423
65-231
3- 97
0-130


.83-1.13
12- 15
49- 67
63-129
11- 23
72-221
14- 39
81-116
25- 52
14- 33
33- 49


.69-.90
13- 16
35- 46
53- 69
10- 14
161-224
17- 24
61- 88
20- 29
13- 25
27- 35









Aqueous extracts of orange pulp, as well as samples of orange juices, were
collected in January and February from 9 commercial plants when mid-season
fruit was being used; also, again in May when late season oranges were being
processed.

Data presented in Table on following page show the ranges found for some of
the constituents in the water extracts, together with those found in orange
juices collected at the same time from the commercial plants. Objectionable
off-flavors were detectable in 3 aqueous extracts produced from mid-season fruit.
The off-flavor in one of these samples was caused by the use of oranges of in-
ferior quality. Since high diacetyl values of 9.7 and 10.2 ppm, together with
plate counts on orange serum agar of 480,000 and 569,000/ml, were also found in
the other 2 samples, it became evident that the off-flavors in these samples re-
sulted from the growth of microorganisms.

The more acceptable extracts were collected from plants where the water
extraction process was carried out rapidly and under good sanitary conditions,
recycling was not a part of the extraction process, and centrifuges were used
to reduce water-insoluble solids, pectinesterase activity, and oxalate-soluble
pectin in the extract before mixing it with evaporator feed juice. (R. L.
Huggart, R. W. Olsen, F. W. Wenzel, R. W. Barron, G. H. Ezell, A. H. Rouse,
C. D. Atkins, E. L. Moore, E. C. Hill, and Roger Patrick.)

High-Density Citrus Concentrate. High-density frozen orange concentrates,
which were previously packed, were examined to determine the effect of degree
-of concentration on flavor stability during storage. Small differences were
detectable during storage at -80 F between the 4-fold (42.00 Brix) and the 6-
fold (58.50 Brix) concentrates. However, marked differences were found in some
of the 4-fold and 6-fold products when they were stored for 24 hours at 800 F,
with better flavor stability being found in the 6-fold concentrate. The flavor
stability, as well as the chemical and physical stability, of some of the 5-
fold (51.50 Brix) orange concentrate was only slightly better than that of the
4-fold products. When 2-, 3-, and 5-fold orange oils were used in place of
coldpressed orange oil, flavorwise the 2- and 5-fold oils were satisfactory.
The 3-fold oil, obtained from another manufacturer, imparted a foreign flavor,
possibly oil of neroli, to the orange concentrate. (R. W. Olsen, R. W. Barron,
and F. W. Wenzel.)

Debittering of Grapefruit Products with Naringinase. Excessive bitterness
in grapefruit juice is not desirable. This bitterness is chiefly caused by a
glycoside, naringin, which may be reduced by the action of the enzyme, naringin-
ase. This enzyme converts naringin by hydrolysis to prunin and/or naringinin
which do not significantly contribute to the bitter taste. An investigation
was initiated to determine the effect of time, temperature, and concentration
of naringinase for effective debittering of 550 Brix frozen grapefruit concen-
trate. Temperatures of -80, 400, 600, and 800 F were used with enzyme concen-
trations varying from .0025% to .080% by weight based on 10.50 Brix juice.
Length of storage and sampling time were varied depending upon the temperature.

The effectiveness of the naringinase was measured organoleptically by tri-
angular taste testing and chemically by the Davis test and various modifications.
Figure on the following page shows the results from the examination of the re-
constituted concentrates. These results indicate the amount of naringin still

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
Q'7 -P -. n in I'. '.,-






NARINGINASE LEVEL NARINGINASE LEVEL
PERCENT BY WEIGHT PERCENT BY WEIGHT
D3 0.0025 o 0.020
.040 A 0.0050 A 0.040 .040
0 0.0100 a 0.080
O 0.0200 *F0
A 0.0400 3


.025 .025 1
S.030 .- 020 (
I-
z



w .020 .020
w z

z .015 .015oa
z z
4 I I I I I cg.
Z 24 48 72 96 120 144 168 24 48
STORAGE AT 60' F. STORAGE AT 80*F. g
HOURS HOURS
S T O R G E A 6 0 F S O R A G A T 0 '0 .| "






-8-


remaining after storage of the 550 Brix concentrate with various levels of
naringinase. Enzyme concentration and storage temperature had a marked effect
on the reduction of naringin and consequently on the bitterness. At 600 F the
concentrate with .020% naringinase showed a reduction of 33% in 32 hours, while
at 800 F with the same conditions a reduction of 66% occurred. With .040%
naringinase the naringin content was reduced 53% in 32 hours at 600 F while
this same reduction was obtained in only 8 hours at 800 F. When .080% narin-
ginase was used together with storage at 80OF for 32 hours, the naringin de-
creased to .013% or to about 90% of the theoretical maximum reduction. (E. C.
Hill and R. W. Olsen.)

Rapid Method for Predicting Potential Clarification and Gelation in
Cnmiercial Frozen Orange Concentrate. Using the following rapid method, which
was applied to commercial samples of frozen orange concentrate, it was possible
to usually predict both potential clarification and gelation. Frozen orange
concentrate is thawed and 50 ml reconstituted with 3 volumes of deionized water.
A 50-ml sample of this juice is centrifuged and the initial relative viscosity
of the serum is determined at 260 C + 0.20 C using an Ostwald pipette. The pH
of another 100 ml of juice is adjusted as rapidly as possible to exactly 6.5 by
adding 4 N NaOH while the juice is rapidly stirred, the pH checked with a pH
meter, and the temperature maintained at 800 F 10 F. As soon as the pH
reaches 6.5, a stopwatch is started and the mixture constantly stirred, but
without further adjustment of pH. After exactly 10 minutes, 3.2 ml of glacial
acetic acid is added as rapidly as possible to the reacted mixture resulting in
a pH of about 3.9. The mixture is centrifuged and then the cloud or turbidity
of the serum is determined by colorimetric measurement of light transmittance;
the final relative viscosity of this serum is also measured.

It was found that a relationship exists, although 100% correlation has not
been established, between the degree of clarification in the serum after the
rapid test and that in frozen orange concentrate after storage for 96 hours at
40OF; also, that the difference between the initial relative viscosity of the
serum and that after the rapid test gave an indication of the degree of gelation
which would occur if the concentrate was stored for 24 hours at 800 F. For best
correlation, the reaction pH, 6.5, has to be carefully determined for each pro-
cessing plant. (Kuang C. Li, M. D. Maraulja, and R. W. Olsen.)

A Survey of the Characteristics of Commercial Frozen Orange Concentrate. -
The flavor, chemical and physical stability, and color of commercial samples of
frozen orange concentrate processed during the 1958-59 season were determined.
With the assistance of personnel of the Agricultural Marketing Service, USDA,
Winter Haven, a total of 197 samples were collected from 23 plants. Taste
panel grades of "good", "fair", and "poor" were given to 33%, 63%, and 4%,
respectively, of these samples. Of the 7 samples which were graded "poor", 4
had undesirable COF (citrus oxidized flavors), 1 was astringent and bitter, 1
was stale, and 1 had the flavor of diacetyl or "buttermilk".

Undesirable semi-gels were found in only 3 samples after storage for 24
hours at 800 F; also, no significant gelation occurred in any of the 197
samples when they were stored for 96 hours at 400 F. However, 3% of the samples
showed definite or extreme clarification after storage for 96 hours at 400 F and
this increased to 13.2% after the concentrates were stored for 24 hours at 800 F.

Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
987 g 9/21/60 FWW






-9-


A Hunter Color Difference Meter was used to measure the color differences
in these orange concentrates. Hunter "a" values ranged from 1.5 to 9.5; "b"
values, 30.2 to 35.3; and "Rd" values, 18.2 to 32.2. (M. D. Maraulja, R. W.
Barron, R. W. Olsen, R. L. Huggart, and E. C. Hill.)


Standardization of Processed Citrus Products. Diacetyl tests were made
on 197 samples of commercial frozen concentrated orange juice collected during
the 1958-59 season. The diacetyl value is the diacetyl equivalent of diacetyl
and/or acetylmethylcarbinol in 25 ml of distillate from 300 ml of reconstituted
juice. Diacetyl values ranged from 0.2 to 3.1 ppm with an average value of 0.9
ppm as compared to a range of 0.2 to 2.9 ppm and an average of 0.9 ppm for the
samples collected during the 1957-58 season. Of the samples tested, 74.3%
showed values of 1.0 ppm or less as compared with 77.7% for the previous season
and 90.2% for the 1956-57 season. Soluble solids in these frozen orange con-
centrates ranged from 40.90 to 44.00 Brix; total acid, as citric, 2.48% to
3.39%; Brix-to-acid ratio, 12.3 to 17.0; and ascorbic acid, 123 to 199 mg/100 g,
which corresponded to 37 to 59 mg/100 ml in the reconstituted juices. Recover-
able oil ranged from 0.008 to 0.063 ml/100 g of conc-ontra~3, corresponding to
0.002% to 0.019% by volume in the reconstituted juices. The apparent viscosi-
ties of 189 samples ranged from 210 to 1,815 cp when determined at 30C C using
a Brookfield viscometer. (E. C. Hill, R. L. Huggart, R. W, Barron, and
G. H. Ezell.)




























Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida.
987 h 9/21/60 FWW