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On behalf of the Institute of Food and Agricultural Sciences, I
extend a cordial welcome to the Twenty-Second Annual Processors
Meeting at Lake Alfred. That we have had a season of surprises must
be taken almost as a matter of routine. More important is that the
citrus market has expanded to accept an adequately large volume of
Dur products at acceptable prices. We must be doing some things
right. That includes our cooperative research program with the
Department of Citrus. We are continually reevaluating our goals, to
keep them in touch with industry problems. In this way, we expect
to continue to merit the cooperation always afforded us by the citrus
Herman J. Reitz, Dir c r
Agricultural Research and
The program this year has several papers of considerable
practical significance. Automatic determination of pounds-solids
is approaching reality and new and more accurate methods for de-
termination of viscosity are under study.
One year's work has been completed on a major new study de-
voted to juice definition. Regular reports will be made annually
until new and more objective methods for juice characterization
The Department of Citrus staff wishes to express its appreci-
ation to the University of Florida Agricultural Research and
Education Center for its cooperation during the past season.
$John A. Attaway
Scientific Research Direcb
Florida Department of Citrus
University of Florida
Agricultural Research & Education Center
P. O. Box 1088
Lake Alfred, Florida 33850
9:00 A.M. Registration
9:30 A.M. WELCOME
John A. Attaway
Scientific Research Director
Florida Department of Citrus
Lakeland and Lake Alfred
Ed H. Price, Jr., Chairman
Florida Citrus Commission
Chairman: Arlen N. Jumper, Chairman, Florida Citrus Commission
Scientific Research Committee.
9:50 A.M. COMPUTERIZING POUNDS-SOLIDS MEASUREMENTS IN THE STATE
TEST ROOMS J. G. Blair, Research Engineer III,
Florida Department of Citrus, Lake Alfred.
The State has used computers in some operations for several years.
The auditing of the Daily Work Sheets has been done on an electronic
calculator and the data put on punch cards which have become the basis
for many machine record reports distributed throughout the citrus
industry. The tables used by the inspectors to find the pounds of
juice per box have also been prepared by a computer.
It is proposed to "put it all together" in a completely automated
State Test Room to reduce the chances of human error. There will be
no need to adjust the fruit sample, look up the pounds of juice per
box and ratio, make manual measurements of Brix and acid, and trans-
pose all these data to the certificate. The fruit samples will be
inspected for unwholesome fruit, weighed, and extracted. After ex-
traction, the juice will be weighed and the pounds of juice per box
automatically determined by the computer. A sub-sample of the juice
will be put into the Brix reader and the acid titrator, both of which
automatically make a measurement. The computer will correct for what-
ever variables exist and determine the proper Brix and acid values.
The pounds-solids and ratio will be calculated and all the information
required for the official certificate will be typed out on the pre-
printed form. The inspector verifies the figures and signs the
10:10 A.M. PHYSICAL AND CHEMICAL CHARACTERISTICS OF COMMERCIAL
FCOJ PACKED DURING THE 1970-71 SEASON R. W. Barron,
Chemist II, Florida Department of Citrus, Lake Alfred.
Flavor and color were determined for 178 samples of commercial FCOJ
during the 1970-71 citrus season. In addition, physical and chemical
analyses relating to juice quality were conducted. Average CR and CY
Hunterlab Citrus Colorimeter values this season were not as good as
those for the two previous seasons.
Numerical averages of flavor scores for 46 samples from the 1970-71
season were divided into five arbitrary flavor groupings based on the
CES 10-point score sheet. The flavor groupings were 6.0, 6.5, 7.0,
7.5, and 8.0.
Correlation coefficients were developed using several characteris-
tics of the juices as independent variables and flavor as the dependent
variable. Similar relationships were developed for the 1969-70 and
10:25 A.M. RHBDLOGICAL EVALUATION OF FCOJ AND HIGHER DENSITY
A.) Consistency of Concentrates Measured with a Bra-
bender Visco-Corder R. L. Huggart, Chemist III, and
E. L. Moore, Research Chemist, Florida Department of
Citrus, and A. H. Rouse, Chemist, University of
Florida Agricultural Research & Education Center,
Consistency or viscosity is an important quality factor to be con-
sidered in preparing high density (Hi-D) citrus concentrates for ready
consumer acceptance. "Paste-like" concentrates are very difficult to
reconstitute, and limit the degree of concentration that may be attained
in an evaporator. Pulp content, pectin grade and other quality factors
determine the viscosity of a Hi-D product.
Three instruments commonly used in the citrus industry for measuring
consistency or apparent viscosity, are the capillary tube (Ostwald),
the orifice tube (pipette) and the rotating disc (Brookfield). Measure-
ments obtained with these instruments are difficult to reproduce due to
instrument used, suspended pulp particles and the thixotropic (gel-sol-
gel transformation) characteristic of some concentrates.
In the food field, corn and flour processing industries have been
successful in measuring the consistency of non-Newtonian materials
with a rotating cup-paddle type instrument. The Department of Citrus
purchased such an instrument, a Brabender Visco-corder, to determine
if the instrument could be used for obtaining easily reproducible,
accurate measurements of concentrate consistency.
To measure consistency on this instrument, approximately 300 ml of
concentrate is placed in a sample cup that can be revolved at infinite
speeds up to 200 rpm. A star style paddle is immersed in the sample.
The torque produced by the consistency of the sample revolving about
the paddle, is measured through rotation of the paddle shaft which is
opposed to a calibrated spring. Torque in centimeter/grams (Brabender
Units) is recorded on a strip chart. Apparent viscosity in centipoise
may be determined using the following equation.
Apparent viscosity (cps) =
Brabender units (torque in cm/g) X 1370 (paddle constant X 1000)
sample cup rpm (shear rate)
The effect of previous shearing or sample conditioning is very
important in measuring Brabender Units (B.U.). An immediate reading
of a thixotropic barrel stock concentrate may be over two times greater
than the consistency indicated after five minutes of conditioning. A
sample may drop another 10 percent in consistency value during the
thirty minutes required to reach equilibrium.
The rate of shear is equally important in determining the viscosity
of thixotropic samples found in FCOJ. Some of the samples examined
at 200 rpm cup speed exhibited less than 60 percent of the consistency
recorded when the sample was measured at a shear rate of 50 rpm. A
few of the samples, which were nearly Newtonian, had a consistency at
200 rpm that was 95 percent of the consistency measured at 50 rpm. A
Newtonian solution will measure the same viscosity at any shear rate.
Concentration and temperature effect on consistency measured with
the Brabender are important. If dilutions of a concentrate are made,
the Brix should be controlled very closely, especially in the higher
ranges of concentration where the effect on consistency is very great.
Sample temperature should be within a degree or two of a selected
temperature (80F preferred) at time of measurement if sample to
sample comparisons are to be made. Effect on viscosity is greater in
the lower temperature ranges where consistency increases very rapidly
per degree of temperature drop.
Fifty-eight commercial FCOJ survey samples collected during the
1970-71 season were examined with the Brabender. Apparent viscosity
at 50 rpm ranged from 153 to 789 centipoises. A very good corre-
lation exists between consistency and USDA free and suspended pulp
measurements. The relationship of consistency to other quality
factors will be investigated.
B.) Apparent Viscosity of Concentrates Measured With
a Tube Viscometer A. H. Rouse, Chemist, University
of Florida Agricultural Research & Education Center,
and E. L. Moore, Research Chemist, and R. L. Huggart,
Chemist III, Florida Department of Citrus, Lake Alfred.
Viscosities of FCOJ and high density citrus concentrates were
measured at 780F with stainless steel tube viscometers having tubes
of 1/8, 3/16, and 1/4 inch I.D. and tube lengths of 12-1/2, 18-3/4,
and 25 inches, respectively. The ratio of tube length to diameter is
100 or higher to assure laminar flow. The viscometer tube is connected
to a sample reservoir which is kept filled with the sample to maintain
a constant flow rate. Each tube was standardized by determining the
flow rates of several Brookfield Viscosity Standards of known centi-
poises. Flow rates in grams per seconds (g/sec) were plotted against
the known centipoises on logarithmic graph paper, 3 cycles X 3 cycles.
The standards, being Newtonian fluids, resulted in straight lines for
each tube and these lines were parallel to one another. A constant or
factor can be calculated from the plotted line (known centipoises X
g/sec) for each tube. The constants for the 1/8, 3/16-, and 1/4-inch
diameter tubes were found to be 55, 135, and 394, respectively. This
constant divided by the flow rate (g/sec) of an unknown concentrate
equals the viscosity. Thus, the equation becomes:
Apparent viscosity = tbcosa
flow rate of sample (g/sec)
The weight of concentrate flowing through the tube is collected in
a tared beaker on a triple beam balance and the time measured with a
stopwatch. The amount of a given weight in grams for a given time in
seconds is reduced to grams per second. Example For the 1/8-inch
diameter viscometer tube, the flow rate for a 25 g sample is 44 sec.
This reduced to g/sec equals 0.568. Substitute this into the above
formula and the apparent viscosity is 96.8.
Apparent viscosity = 0.568 = 96.8
TECHNIQUES: Practical flow rates are obtained either by the amount of
fluid timed or by increasing the flow rate with the use of a larger
diameter tube. Tentative limits of viscosities suggested for the 3
tube viscometers are:
Less than 400 cps, 1/8-inch diameter tube
400 to 1000 cps, 3/16-inch diameter tube
Greater than 1000 cps, 1/4-inch diameter tube
Usually the 1/8-inch diameter tube was satisfactory for 450 Brix FCOJ.
Large pulp particles, sometimes found in the floating pulp of FCOJ,
interfere with the flow rates in the 1/8-inch diameter tube. This
interference is eliminated by using the 3/16-inch diameter tube. It
is advisable that 2 or more samples be collected in the tared beaker
and that the difference in flow rate be no greater than 5%.
The table below shows apparent viscosity ranges of 58 FCOJ survey
samples in centipoises as determined by the tube and Brookfield (LVT)
Minimum 21 133
Median 50 430
Maximum 176 2,475
The consistency in the flow rates of a thixotropic high-density
concentrate is obtained by using the 1/4-inch diameter tube and by
gently keeping the fluid disturbed in the sample reservoir. This is
accomplished with a rubber policeman attached to one end of a glass
stirring rod and the other end inserted into the chuck of a variable
speed motor. The stirring rod is turned at approximately 120 rpm.
Listed below are apparent viscosities of some high-density com-
mercial products as determined by the tube and Brookfield (HAT)
viscometers. Also shown are the quantities of water-insoluble solids,
water-soluble pectin, and total pectin in these concentrates.
Concentrates Orange Orange Orange Grapefruit Tangerine
o Brix 57 70 73 60 59
Tube 217 10,078 1,731 823 39,800
Brookfield 2,415 45,000 7,400 4,056 96,400
Water-insol. 780 854 388 682 1,216
Water-sol. 162 242 150 263 296
Total pectin 381 519 329 481 530
Thixotropic characteristics of high-density concentrates causing
high viscosities are the results of individual factors such as water-
insoluble solids, water-soluble pectin, low methoxyl pectin, proto-
pectin, total pectin, polymerization of the pectin molecule, and the
creation of a sugar-pectin-acid gel system or combinations of these
11:00 A.M. OJ BREAK
11:15 A.M. CURRENT STATUS OF VITAMIN C IN FLORIDA PRODUCED
FROZEN CONCENTRATED AND CHILLED ORANGE JUICE -
P. J. Fellers, Food Technologist, and R. W. Barron,
Chemist II, Florida Department of Citrus, Lake
Data are presented for 89 frozen concentrated and chilled orange
juice samples which were collected and analyzed for vitamin C
(ascorbic acid) content monthly over the 1970-71 citrus season.
Representative data on rate of loss of vitamin C from samples of
chilled juice in different opened and recapped container types and
sizes held at 400F storage are given.
11:25 A.M. MALONALDEHYDE IN AQUEOUS ORANGE JUICE ESSENCES -
R. J. Braddock, Assistant Food Scientist, University
of Florida Agricultural Research & Education Center,
and D. R. Petrus, Chemist III, Florida Department of
Citrus, Lake Alfred.
Malonaldehyde has been identified as a component of commercial
aqueous orange juice essences. This compound reacts with 2-thiobar-
bituric acid to form a pink-colored complex which can be quantitatively
determined from its characteristic absorbance at 532 nm. The quantity
of malonaldehyde in essence was found to vary among processors and to
be affected by abuse given essences during periods of oxidative deter-
ioration. All commercial essences examined contained malonaldehyde,
with concentrations ranging from 10-100 ppm in aqueous essence. Re-
sults indicate that the measurement of malonaldehyde may prove to be
a valuable new analytical method useful in the quality evaluation of
commercial aqueous orange essences.
11:45 A.M. DECOMPOSITION OF POLYUNSATURATED FATTY ACIDS DURING
PROCESSING OF ORANGE JUICE R. J. Braddock, Assistant
Food Scientist, University of Florida Agricultural
Research & Education Center, Lake Alfred.
Fatty acid analyses of major phospholipids and free fatty acids
from fresh, pasteurized and frozen concentrate were performed
immediately before and after processing. The intent was to study the
effect of processing on oxidatively labile and nutritionally import-
ant fatty acids in the juice, e.g. linoleic and linolenic acids.
Linoleic acid was slightly affected by commercial processing con-
ditions. Heat stabilized, canned single strength juice exhibited a
10% loss of this acid, while canned frozen concentrate showed a 5%
loss when compared to freshly extracted juice. Passage through a
heat exchanger during stabilization apparently caused a greater change
in the linoleate content than evaporation during the concentration
Phospholipid determinations (mg lipid P/100 ml juice) showed
values of 1.0, 1.3, and 1.3 for the total phospholipids extracted
from fresh, pasteurized and frozen concentrated orange juice, re-
spectively. Values for the latter two are probably greater because
of the physical disruption of tissue during processing.
This data could be interpreted as meaning that the commercial
processes mentioned do not severely damage the lipid fractions
studied and that other factors, such as handling or storage before
and after processing may be more important to maintenance of good
lipid quality, and thus, good juice quality.
12.:05 P.M. PEEL OIL CONTENT, QUANTITY AND RECOVERY OF CITRUS
ESSENTIAL OILS FROM THE VARIOUS PROCESSED CULTIVARS
OF CITRUS J. W. Kesterson, Chemist, University of
Florida Agricultural Research & Education Center,
and S. V. Ting, Research Biochemist, Florida Depart-
ment of Citrus, Lake Alfred.
Data is presented to show the peel oil content for three different
processing seasons of various citrus cultivars, as follows: Hamlin,
Parson Brown, Pineapple, Valencia and Temple oranges; Duncan, Marsh,
Ruby Red and Foster pink grapefruit; Dancy tangerines; Orlando tange-
los; Persian limes and Florida lemons. The two factors found to have
the greatest influence on peel oil content are budwood selection and
The total potential of citrus essential oils that can be recovered
from processed fruit based on the 1969-70 processing season amounted
to approximately 79 million pounds. Due to the increased interest in
d-limonene this could become a valuable asset to the Florida Citrus
Industry. Preliminary information is presented on one processing pro-
cedure for the recovery of this commodity.
12:20 P.M. LUNCH
Chairman: Henry Cragg, Chairman, Florida Citrus Commission
1:40 P.M. THE JUICE DEFINITION PROGRAM -
A.) Introduction of Overall Objectives J. A.
Attaway, Scientific Research Director, Florida
Department of Citrus, Lake Alfred.
As the Florida citrus processing industry moves to solve the prob-
lems of the 70's, the need for a more detailed understanding of the
characteristics which make juices desirable or undesirable becomes
apparent. The industry has long relied on a limited number of
analyses such as Brix, acid, ratio, and oil to define product quality.
Frequently, however, products with "satisfactory" analytical values
are poorly received by the consumer. This indicates the possible
presence within the product of other constituents which contribute to
or detract from product quality.
Another important need has resulted from the request that Federal
standards of identity be adopted for diluted drinks. If standards are
ultimately adopted which specify that certain categories of drinks
contain defined amounts of orange juice, it will be important for us
to have an intimate knowledge of all constituents of juice and the
ranges through which they can normally be expected to vary. In
addition, Federal standards of quality have been proposed for FCOJ,
and proposals may soon be made for like standards on various pasteur-
ized and chilled orange juice products. An increased knowledge of
desirable and undesirable constituents will permit more accurate
definition of quality in those orange juice products.
If information developed in this program makes it possible to
define "good usable juice" more precisely, those charged with the
responsibility of setting the juice yield factors will also benefit
from these studies.
The first years work has involved a comparison of juices prepared
using a harsh, destructive squeeze designed to produce an undesirable
product, with juices prepared using a soft squeeze designed to pro-
duce a good product. A total of 24 juices, 12 prepared using a harsh
squeeze and 12 with a soft squeeze, were studied. Included were 1 set
of 'Hamlin', 3 sets of 'Pineapple', and 8 sets of 'Valencia' samples.
Each juice sample was subjected to 32 separate analyses, the most
significant of which will be used for future studies, and correlated
with flavor scores determined on a 9 point Hedonic scale. No firm
recommendations are contemplated based on data from only one season,
hut it is hoped that when data from 3-5 year work has been accumu-
lated we will be able to make a more precise chemical and physical
definition of orange juice.
1:45 P.M. B.) New Types of Instrumental Analyses D. R. Petrus,
Chemist III, Florida Department of Citrus, Lake
Various instrumental techniques have been applied to investigate
and characterize citrus juices and related products. The presen-
tation will be concerned with the total reflectance, fluorescence,
phosphorescence and wideline nuclear magnetic resonance phenomena
which may be characteristic of orange juice. The applications are
new and the results appear quite encouraging.
1:55 P.M. C.) Folic Acid An Important Vitamin E. C. Hill,
Research Bacteriologist, Florida Department of
Citrus, Lake Alfred.
The presence of folic acid in orange juice has long been known.
However, research by Dr. Richard R. Streiff of the University of
Florida College of Medicine has recently demonstrated that there are
much larger amounts present than was previously believed. Also, the
folate present in orange juice is in the monoglutamate form which is
directly absorbed and does not have to be broken down by intestinal
enzymes as do the polyglutamate forms. Although some other foods,
such as meats, have a higher folic acid content than orange juice,
they must be cooked and this destroys a large amount of this vitamin.
Most of the folate contained in fresh orange juice is retained after
processing. This is probably due in part to the relatively mild heat
treatment used by the citrus industry and partly due to the presence
of large quantities of ascorbic acid which seems to protect the folate.
Folate deficiency in man causes an anemia, which Dr. Streiff re-
gards as second in importance only to that produced by iron de-
Three to six ounces of orange juice per day would supply 50-100
mcg of folic acid which is more than that suggested as the minimum
daily requirement for an adult.
2:00 P.M. D.) Flavonoid Content E. C. Hill, Research
Bacteriologist, Florida Department of Citrus,
Davis tests were run on samples of orange juice prepared for the
juice definition program to determine the effect of harsh and soft
squeeze on the flavonoid glycosidee) content of the juice.
A marked difference was found. The soft squeezed juices contained
flavonoids ranging from 76 to 119 mg per 100 ml while the harsh
squeezed juice range was 141 to 259 mg per 100 ml. In each case the
flavonoid content of the hard squeezed juice was almost twice that of
the same fruit extracted with a soft squeeze.
Although the flavor grade of all the harsh squeezed juices was
less than 4, it is unlikely that the flavonoids of oranges con-
tributed to these low flavor scores in any marked degree.
2:05 P.M. E.) Protein, Sugar, Mineral and Ash Analyses -
S. V. Ting, Research Biochemist, Florida Department
of Citrus, Lake Alfred.
Sugars. Although sugars are the main constituents of orange juice
solids and are determining factors of the taste and quality of juices,
there was no noticeable difference in the amounts of the three main
component sugars of the juices obtained by either harsh or soft
Mineral constituents. Juices obtained by harsh squeezing had nearly
two or three times as much calcium as the corresponding juices obtained
by soft squeeze. They were also found to be higher in magnesium and
sodium but lower in potassium than the soft squeeze juices. The
differences in these elements, although consistent, were not as pro-
nounced as that in calcium.
Protein content. The determination of protein was made by a semi-
micro Kjeldahl procedure on the alcohol insoluble solids (AIS) of the
juice. The AIS were prepared by extracting the juice with progressive-
ly higher concentrations of ethyl alcohol followed by filtering. The
main components of the AIS prepared in this manner are pectin, protein,
and polysaccharides including cellulose. Both the AIS and protein were
found to be higher in juices extracted with harsh squeeze than those
with soft squeeze. There was a good correlation between these two
constituents. Juices with high flavor scores were lower in their pro-
tein and AIS contents. Either or both of these constituents may have
a deleterious effect on the flavor of the juice.
2:15 P.M. F.) Brix, Acid, Ratio, Pulp and Serum Viscosity -
R. W. Barron, Chemist II, Florida Department of
Citrus, Lake Alfred.
Several analyses of processed orange juices were conducted during
the 1970-71 season. In all instances flavor of juice from soft
squeeze fruit was better than that from harsh squeeze. Pulp, serum
viscosity, % oil, and B/A ratio values were lower, while acid values
were higher for soft squeeze than harsh, with Brix values usually
being lower for soft squeeze but in some instances the same as for
Correlation coefficients were developed using characteristics of
the juices as independent variables and flavor as the dependent vari-
able. A satisfactory correlation between flavor and pulp was obtained.
2:25 P.M. G.) Aldehyde, Oxygenated Terpene, and COD Analyses -
M. H. Dougherty, Research Engineer II, Florida
Department of Citrus, Lake Alfred.
Juices were analyzed for COD, oxygenated terpenes and total alde-
hydes. Harsh and soft squeeze had very little, if any, effect on the
COD content of the juices. However, the harsh squeeze juices had
about twice the oxygenated terpene value of the soft squeeze juices.
The values for total aldehydes were slightly higher for the harsh
squeeze juices but in no instance were the values any higher than
might be found in a fresh juice.
2:35 P.M. OJ BREAK
2:50 P.M. H.) Limonin Content J. F. Fisher, Research
Chemist, Florida Department of Citrus, Lake Alfred.
Limonin is a bitter compound that may be found in some processed
citrus juices. The amount of limonin in unabused Florida citrus
fruits (with the exception of seeds) is nil. However, a nonbitter
limonin precursor is present. When juice is extracted from the
citrus fruits this nonbitter compound enters the juice from the
crushed tissues. The acidity of the juice along with heat converts
the nonbitter compound to the bitter limonin.
A thin-layer chromatographic procedure developed by Dr. Maier of
the U.S.D.A. was employed to determine the levels of limonin in juices
obtained from Hamlin, Pineapple and Valencia oranges. These values
correlated well with the flavor scores. Harsh squeezed juice showed
high limonin values and low flavor scores. Soft squeezed juice gave
zero or low limonin and higher flavor scores.
2:55 P.M. I.) Light Transmission (Cloud) and Hunter Colorimeter
Values R. L. Huggart, Chemist III, Florida Depart-
ment of Citrus, Lake Alfred.
Percent light transmission or cloud, was measured on a Lumetron
Model 401 colorimeter. Citrus Red (CR) and Citrus Yellow (CY) were
determined with a Hunterlab Citrus Colorimeter. Equivalent color
scores (ECS) were calculated using the equation for FCOJ, ECS =
22.510 + 0.165 CR + 0.011 CY. 'Hamlin', 'Pineapple' and 'Valencia'
orange juices in this program were extracted using either a soft or
An analysis of variance was made using flavor score as the depend-
ent "Y" value and cloud, CR, CY or color score as the independent '""
The highest correlations in all of these data were found between
flavor scores and cloud values. The coefficients were high for flavor
score and cloud values of each variety. This relationship existed for
all samples as a group or for samples of individual varieties. This
inverse relationship (less cloud, better flavor), was best in the
'Valencia' samples explaining 88 percent of the variation, and.ex-
plained 75 percent of the variation when all samples were considered
together. Citrus Yellow correlated with flavor changes in the 'Hamlin
samples. CR and CY correlated with flavor changes in 'Pineapple' and
'Valencia' juices. Equivalent color score was a good indication of
flavor in the 'Pineapple' and 'Valencia' juices but was not indicative
of flavor in the 'Hamlin' juices or in a linear regression analysis
equation fitting the samples of all varieties together.
Cloud measurements were the best indication of flavor in a simple
analysis of all varieties with a correlation coefficient of 0.87. A
multiple linear regression analysis of cloud and citrus yellow with
flavor raised the coefficient to 0.90. The addition of CR to the
equation failed to raise the coefficient above 0.90.
J.) Water-Insoluble Solids and Pectins A. H. Rouse,
Chemist, University of Florida Agricultural Research
& Education Center, Lake Alfred.
Each juice was analyzed for water-insoluble solids (WIS) and for
pectins. The pectic fractions were divided into 3 groups on the
basis of their solubility in water, in ammonium oxalate, and in sodium
Minimum and maximum values for WIS and the pectic fractions in the
juices are summarized in Table 1. Results are expressed as mg/100 g
Soft Squeeze Harsh Squeeze
Min. Max. Min. Max.
Water-insoluble solids 112 171 204 770
Water-sol. pectin 14 27 42 101
Ammonium oxalate-sol. pectin 8 16 14 41
Sodium hydroxide-sol. pectin 11 39 19 74
Total pectin 47 80 88 216
For harsh squeezed juices, the higher WIS values (351 to 770
mg/100 g) were found in Hamlin and Pineapple juices, while the lower
values (204 to 266 mg/100 g) were always found in the Valencia juices.
The soft squeezed juices did not show this same pattern for the
higher WIS value from early and midseason oranges and the lower WIS
values from late season fruit.
Poor flavored orange juices in this project were associated with
the harsh squeeze. All 12 of the juices that were harsh squeezed re-
ceived averaged flavor scores below 4, while 11 of the soft squeezed
juices were above 5. The comparison of averaged flavor scores to WIS
for the 12 soft squeezed juices and the 12 harsh squeezed juices are
shown in Table 2.
Flavor Number and WIS
Scores Treatment mg/100 g juice
6 to 7 7 soft 116 to 146
5 to 6 4 soft 112 to 171
4 to 5 1 soft 142
1 to 4 12 harsh 204 to 770
The ratio of the water-soluble pectin in the harsh squeezed juice
to the water-soluble pectin in the soft squeezed juice was always
greater than the ratios of the other 2 pectic fractions in relation
to harsh and soft squeeze. Examples of these ratios of the pectic
fractions are shown in Table 3.
Orange Water- Ammonium oxalate- Sodium hydroxide-
variety soluble soluble soluble
Hamlin 4 to 1 2.6 to 1 1.9 to 1
Pineapple 3 to 1 1.9 to 1 1.5 to 1
Valencia 3.3 to 1 1.7 to 1 1.1 to 1
K.) Correlation of Objective Measurements with
Subjective Indices of Quality and Consumer
Preference P. J. Fellers, Food Technologist,
and B. S. Buslig, Research Biochemist, Florida
Department of Citrus, Lake Alfred.
General operation of the taste panel for the juice definition pro-
gram is discussed.
Seven of 21 objective measurements made on the orange juices show-
ing correlations with flavor of 0.8 or better are utilized in multiple
regression equations to obtain an estimate of flavor quality. In
addition, 4 easily measured characteristics of orange juice cloud,
pulp, oil and serum viscosity, and each giving 0.75 correlation or
better with flavor are also used in multiple regression analysis to
predict flavor quality.
These Abstracts are for limited distribution only. Information
herein is not to be used for publication without permission.
Acknowledgment for helpful assistance is made to Fred Schopke,
Ben Wood, Irene Pruner, Betty Murphy, Mary Smith, Alice Barber,
Florence Wolff, Roger Waters, Joe Collins, Fred Givens, Roy
Albright, Van Harrell, Otto Hansen, and to all other personnel of
either the University of Florida Agricultural Research & Education
Center or the Florida Department of Citrus who helped in many and