Group Title: Citrus Station mimeo report - Florida Citrus Experiment Station ; 54-11
Title: Flavor studies on orange concentrates made from juices heated prior to concentration
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Permanent Link: http://ufdc.ufl.edu/UF00072358/00001
 Material Information
Title: Flavor studies on orange concentrates made from juices heated prior to concentration
Series Title: Citrus Station mimeo report
Physical Description: 7 leaves : ; 28 cm.
Language: English
Creator: Wenzel, F. W
Olsen, R. W
Atkins, C. D
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: 1954
 Subjects
Subject: Orange juice -- Flavor and odor -- Florida   ( lcsh )
Concentrated fruit juices -- Preservation -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: F.W Wenzel, R.W. Olsen, and C.D. Atkins.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00072358
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 74323152

Full Text

Flavor Studies on Orange Concentrates Made from Juices Heated Prior to
Concentration*

F. W. Wenzel, R. W. Olsen, and C. D. Atkins


This investigation was concerned with a comparison of various methods for
evaluating the flavor of citrus juices and also the effect of heat treatment on
the flavor of frozen orange concentrate made from juice heated prior to concen-
tration.

The orange concentrates used in this study were made from Pineapple and Va-
lencia oranges which were harvested and processed in March and June, respectively.
After thoroughly mixing the fruit, some of it was held at 40oF. for several days
because the four packs of concentrates from each variety of fruit, needed for this
investigation, could not be processed in one day.

The juice for processing was obtained using a Citro-Mat extractor and a Food
Machinery finisher (Model 35) with a 0.030 inch screen. The pasteurizer used con-
sisted of a heating and a cooling coil of 5/32 inch I.D. stainless steel tubing.
Hot water was circulated around the heating coil and tap water around the cooling
coil. The flow rate was 1900 ml./min. The time required to raise the temperature
of the juice from room temperature to the desired temperature was 12 seconds and 8
seconds were necessary for lowering the temperature to 850F. Heating temperatures
of 155, 1750, and 1950F. were used. All temperatures were controlled by a Taylor
controller and checked with a standardized Brown potentiometer pyrometer. After
being heated and cooled the juice was concentrated to 550Brix in the two-stage,
low-temperature pilot plant evaporator. The 550Brix concentrate was cut back to
420Brix by blending with juice that was not heated. The 420Brix concentrate was
filled into 6 oz. cans, frozen and stored at -80F. Analytical data for the Pine-
apple and Valencia orange concentrates prepared are given in Table 1, which also
shows the percentage of pectinesterase inactivation resulting from heat treatment
of the juices at 1550, 1750, or 1950F.

Difference, ranking, and scoring methods were used for evaluation of the fla-
vor differences and acceptability of the eight packs of frozen orange concentrates.
The taste panels used were either a small, experienced panel of 7 staff members
engaged in processing research or a larger panel of approximately 50 Station per-
sonnel including staff members, laboratory assistants, clerical empolyees, and
skilled laborers. The latter panel was considered to be a small consumer group and
no effort was made to obtain the opinion of a large consumer group. Results of
the use of the various methods for flavor evaluation of the orange concentrates
made from juice heated before evaporation are shown in Tables 2, 3, 4, and 5 which
represent the judgments of the small, experienced taste panel off7j persons. All
reconstituted juices tasted by this panel were at room temperature with 'the low-
est temperature being 700F. Juices were served to the/larger Station panel both
at room temperature and cool (400 to 50F.) and results' reported in Table 6 are
based on the judgments of this panel. r

Results (Table 2) from the use of the difference method (2:1 or 3:2 compari-
sons) indicated that there were significant differences ini'bth the Pineapple and
Valencia concentrates made from unheated juices and those made"frbm'juices heated
to 1550, 1750, or 195F., with the flavor difference being slightly greater in the
Pineapple concentrates than in the Valencia concentrates.


*American Can Company cooperating through the establishment of a grant-in-aid.

Citrus Station Mimeo Report 54-11. Florida Citrus Experiment Station and Florida
Citrus Commission, Lake Alfred, Florida. 471e-10/6/53-FlW





The results obtained by the difference method (Table 2) were confirmed when
the small, experienced taste panel used the ranking and scoring methods (Tables
3 and 4). In the ranking method each taster was given one sample of four juices
and requested to arrange the samples in order of decreasing acceptability by pla-
cing the juice most preferred first and the least preferred juice last. At the
same time the four juices were scored on the basis of overall quality (excellent,
good, fair, poor, objectionable) and on the degree of off-flavor (none, slight,
definite extreme) attributed to heat treatment. The judgments of the panel
(Table 45 indicated a gradual decrease in overall quality and an increase in off-
flavor in the Pineapple concentrates as the temperature of heat treatment of the
juices before concentration was increased from 1550 to 1950F. Again these dif-
ferences were more noticeable in the Pineapple concentrates than in the Valencia
concentrates. These results were again confirmed by data obtained by the scoring
method and presented in Table 5, these data being based on the 774 judgments made
on the 8 packs of orange concentrates by the small, experienced taste panel during
the course of this investigation.

To determine consumer acceptability of the orange concentrates, the opinions
of approximately 50 Station personnel were obtained by having them taste each pro-
duct several times. The scoring method was used and the taster requested to indi-
cate the overall quality as excellent, good, fair, poor, or objectionable, desig-
nating excellent, good, or fair scores only if the juice was acceptable as frozen
orange concentrate and would be purchased again by the taster. The importance of
the temperature of the juice at the time of tasting is evident from the data in
Table 6 which shows that over 20% of the Pineapple concentrates made from heated
juices were scored poor or objectionable (not acceptable) when the juices were tas-
ted at room temperature, whereas a marked increase in acceptability was noted when
the juices were served cool (400 to 500F.). Scoring of the cool Pineapple juices
indicated some difference between the concentrates prepared from unheated and heated
juices, but little difference between the concentrates made from juices heated to
1550, 1750, or 195 F. Comparison of data in Tables 5 and 6 definitely shows that
the small, experienced taste panel was more discriminating than the larger Station
panel. Finally, although flavor differences were previously shown to exist in
some of the Pineapple and Valencia concentrates, the results presented in Table 6
indicate that when cool juices were served 84? or more of the judgments were that
the products were acceptable regardless of whether they were made from unheated or
heated juices.

The difference, ranking, and scoring methods used in this study gave relative-
ly similar results and therefore are suitable for the evaluation of flavor differ-
ences in citrus juices. The general conclusions that have been made will be check-
ed by statistical analysis of the data contained in this report.

The quality of frozen orange concentrate may be impaired by many factors,
such as use of fruit of poor quality, poor processing procedures which result in
excessively high juice yields, bacterial spoilage during evaporation, and improper
storage conditions. To this list should be added the use of heat treatment that
is not properly and carefully controlled. On the basis of the results presented
in this report it would seem advisable to recommend that the time-temperature con-
ditions for heat treatment of juice prior to evaporation should be maintained at
the lowest possible level that will prevent undesirable microbiological and enzymic
changes and will result in a product with such stability that it will be of good
quality when used by the consumer,




Citrus Station IMimeo Report 54-11. Florida Citrus Experiment Station and Florida
Citrus Commission, Lake Alfred, Florida. 471f-10/6/53-Fl-hW










TABIE 1


Frozen orange concentrates made from juices heated prior to concentration


Date Ht Concentrate Reconstituted juice
processed treatment Brix pH Brx Acid Brix/Acid Pulp Oil Pectinesterase activity
28C0. Spindle % ratio % (PE.u.)a Inactivation-%
Pineapple orange

3-5-53 None 42.5 3.8 12.9 0.76 17.0 15.0 0.005 31.8 None
3-9-53 155F. 42.5 3.8 12.7 0.75 16.9 12.0 0.002 14.1 55.7
3-6-53 1750F. 42.3 3.8 12.6 0.75 16.8 10.5 0.004 5.4 83.0
3-10-53 1950F. 42.1 3.8 12.7 0.74 17.1 11.0 0.002 4.0 87.4
Valencia orange

6-22-53 None 42.0 3.9 12.4 0.65 19.1 8.0 0.005 23.1 None
6-24-53 1550F. 42.2 3.9 12.5 0.66 18.9 6.0 0.009 14.7 36.4
6-23-53 1750F. 41.7 3.9 12.2 0.64 19.1 6.0 0.002 3.3 85.7
6-25-53 1950F. 42.0 3.9 12.2 0.63 19.4 5.0 0.008 1.3 94.4


a Pectinesterase units
2800. as OBrix.


(PE.u.) per gram soluble solids x 1000. Soluble solids measured by refractometer at


Citrus Station Mimeo Report 54-11.
Lake Alfred, Florida. 471b-10/6/53


Florida Citrus Experiment Station and Florida Citrus Commission,
- FvW









TABIE 2

Difference method for flavor evaluation of citrus juicesb


Concentrates compared as
indicated by temperature
of heat treatment



None vs. 1550F,

None vs. 1750F.

None vs. 1950F.

1550F. vs. 1950F.

1550F. vs. 1750F.

1750F. vs. 1950F.


Reconstituted concentrates
Pineapple Valencia
2:1 comparison 3:2 comparison 2:1 comparison
3 replications 2 replications 3 replications
Separated correctly

Yes No Yes No Yes No
% % % % % %

95 5 100 0 84 16

95 5 85 15 89 11

95 5 86 14 94 6


63

52

48


55

50

55


b Taste panel consisted of 7 persons.

Citrus Station Mimeo Report 541-U. Florida Citrus Experiment Station
lake Alfred, Florida. 471c-10/6/53 FWW


and Florida Citrus Commission,


_ I ----


__ --


_ __ _




TABLE 3


Ranking method for flavor evaluation of citrus juices


Eeat Reconstituted concentrates
treatnt Rank Pineapple Valencia
treatFrequency i-ean rank Frequency Kean rank

None 1 21 18
2 0 2
3 0 1
4 0 1.00 0 1.19

1550F. 1 0 1
2 12 7
3 5 6
4 4 2.62 7 2.91

1750F. 1 0 2
2 7 9
3 6 6
4 6 3.05 4 2.57

195F. 1 0 0
2 2 3
3 10 8
4 9 3.33 10 3.33



TABLE 4

Comparison of ranking and scoring methods for flavor evaluation of citrus juices

Reconstituted concentrates
Pineapple Valencia
Heat treatment Hone 1550F. 1750F. 1950F. Hone 155F. 175F. 1950F.
Ranking test
Iean rank 1.00 2.62 3.05 3.33 1.19 2.91 2.57 3.33
Scoring test
Excellent-% -- S -
Good-" 38 -- -- 62 5 14 -
Fair-4 62 90 76 52 38 95 61 100
Poor-% -- 10 24 48 -- 5 -
Objectionable-0 -- -- -- "
Degree of off-
flavor attribu-
ted to heat
treatment
None-l 95 .. 95 19 33 1l
Slight-% 5 81 67 43 5 76 57 62
Definite- 19 33 57 5 10 24
Extreme-% -
Citrus Station kimeo Report 54-11. Florida Citrus Experiment Station and
Florida Citrus Commission, Lake Alfred, Florida. 471a-10/6/53 FI'M











TABLE 5

Scoring method for evaluation of flavor of citrus juicesc


Reconstituted concentrates
Pineapple Valencia
Heat treatment None 155F. 175 '. 195F. None 155t. 175 t. 195-.
Scoring test
Excellent-% -- -- -- -- -- -
Good-% 38 5 2 4 61 18 9 3
Fair-% 61 90 84 61 38 81 87 97
Poor-% 1 5 1U 35 1 1 -
Objectionable-% -- -* -
Degree of off-flavor
attributed to
heat treatment

None-% 90 6 6 5 92 36 31 24
Slight-% 10 77 54 28 8 59 58 52
Definite-% 17 40 67 -5 11 2
Extreme-% -- -- -- -- "

Acceptability

Acceptable-% 99 95 86 65 99 99 96 100
Not acceptable-% 1 5 14 35 1 1 4 -
c Taste panel consisted of 7 persons, who made 774 total judgments on the 8 concentrates.

Citrus Sta;,nn Mimeo Report 54-11. Florida Citrus Experiment Station and Florida Citrus
Commission, Lake 4fred, Florida. 471d-10/6/53 -FW












TABLE 6

Scoring method for the evaluation of flavor of citrus juices


Juice at room temperature when tasted Juice at 40 to 500F. when tasted
Pineapple concentrates Pineapple concentrates Valencia concentrates
Heat treatment None 155F. 175Fi. 195 F. None 155F. 175'F. 195'F. None 155 F. 175F. 1950F.

No. of judgments 201 209 200 200 159 155 156 158 150 137 1S5 146
Scoring test
Excellent-% 7 -- 9 --- 7 5 4 3
Good-% 60 31 34 27 66 52 46 31 56 45 60 73
Fair-% 31 41 45 47 24.5 41 48 53 30 48 33 22
Poor-% 2 24 19 22 0.5 3 6 13 7 2 3 2
Objectionable-% -- 4 2 4 -- h -- 3 -- --
Acceptability
Acceptable-% 98 72 79 74 99.5 93 91 84 93 98 97 98
Not acceptable-% 2 28 21 26 0.5 7 6 16 7 2 3 2


Citrus Station Mimeo Report 54-11. Florida
lake Alfred, Florida. 471-10/6/53 FWW


Citrus Experiment Station and Florida Citrus Commission,




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