Group Title: Citrus Station mimeo report - Florida Citrus Experiment Station ; 54-3
Title: Time-temperature-fold relationships for heat inactivation of pectinesterase in citrus juices
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Permanent Link: http://ufdc.ufl.edu/UF00072351/00001
 Material Information
Title: Time-temperature-fold relationships for heat inactivation of pectinesterase in citrus juices
Series Title: Citrus Station mimeo report
Physical Description: 7 leaves : ; 28 cm.
Language: English
Creator: Atkins, C. D
Rouse, A. H
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: Citrus juices -- Composition -- Florida   ( lcsh )
Pectin -- Florida   ( lcsh )
Fruit juices -- Pasteurization -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: C.D. Atkins and A.H. Rouse.
General Note: Caption title.
 Record Information
Bibliographic ID: UF00072351
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 74144040

Full Text

Time-Temperature-Fold Relationships for Heat Inactivation of Pectines-
terase in Citrus Juicesa
0. D. Atkins and A. H. Rouse

Orange juices at 1, 2, 3, and 4-folds (120, 230, 33, and 42oBrix) were heat-
ed to temperatures ranging from 1250F. to 2100F. in 3, 6, and 12 seconds to deter-
mine the relationship of time, concentration, and temperature upon pectinesterase
activity. Previously all data accumulated were based on single-strength juices.
The effect of heat as a "cloud" stabilizer in these folded juices, measured in
terms of light transmission, was also desirable.

Experiments on this phase of heat treatment were begun the latter part of
February at which time Pineapple orange juice had a pH 3.8. As a result only one
pH level was used for this variety of orange. The various folds of Valencia orange
juices were made at two pH levels, pH 3.6 and pH 4.1, but results at this time are
completed only on the samples at the pH 3.6 level.

Pineapple and Valencia oranges were extracted on the Rotary press with moder-
ate pressure and the expressed juices finished in a Food Machinery, Model 35, fin-
isher with a 0.030 inch perforated screen. The Pineapple juice contained a pulp
content of 9.0% by volume and pH 3.8, whereas the two finished Valencia juices
contained 7.5% pulp and pH 3.6 and 4.1. The Pineapple orange juice was concentra-
ted to 2, 3, and 4-folds, whereas the Valencia orange juice was concentrated to
42OBrix and then cut-back to 1, 2, and 3-folds with cooled distilled water. The
folded juices were then poured into 10 gallon containers and stored at -8F. un-
til needed.

The time-temperature-fold relationships for the heat inactivation of pectin-
esterase in Pineapple and Valencia orange juices are presented in Tables 6 and 7.
Both the Pineapple orange juice, pH 3.8 and the Valencia orange juice, pH 3.6, at
1, 2, 3, and 4-folds, when heated for 12, 6, and 3 seconds, required 1950F., 2000F.,
and 2050F., respectively, for complete inactivation of pectinesterase activity.
Concentrating the juices and then heat treating them did not result in lower temp-
erature for complete pectinesterase inactivation. However, the general trend was
to inactivate a higher percentage of the enzyme at the lower fold when heated from
1250F. to 1550F., and above this temperature the percentage of inactivation for a
specific holding time, regardless of fold, was ab1butihesame.

Temperature differentials in a tubular pateurizer between the actual heated
juice and concentrate temperatures and the hting mediu"'temperatures for 1, 2,
3, and 4-folds for 0.8, 3, 6, and 12 secondsIare presented in;Table 8. There is
no significant temperature differential be Wengthe'temperatures of the 1 and 4-
fold juices and the temperature of the heatingmedium for the 12 seconds holding
time, but the temperature differential for the 3'second holding"time varied from
7 to 13.50F. for the 1-fold juices and 290 to'39.50F; for-the 4-fold juices.

Cloud stability for Pineapple and Valencia orange juices at 1, 2, 3, and 4-
folds when heat treated for six seconds from 1250F. to 2000F. are presented in
Tables 9 and 10 as clarification measured by percentage of light transmission of
centrifuged reconstituted juice. Clarification of these juices is shown initially
and after short-term storage for 24 hr. at 800F. Results in Table 9 show definite

a American Can Company cooperating through the establishment of a grant-in-aid.
Citrus Station Mimeo Report 54-3. Florida Citrus Experiment Station and Florida
Citrus Commission, Lake Alfred, Florida. 463-10/6/53 CDA









clarification in 4-fold Pineapple concentrates made from heated juices showing
pectinesterase inactivation ranging from 74.7 to 100% (Table 6). It is believed
that clarification occurred in these products because such clarification had taken
place either during the concentrating, freezing and thawing, or holding of the con-
centrates prior to heat treatment. Initial clarification on the Pineapple juices
were obtained only for the 1-fold products. If control samples had been taken of
the 2, 3, and 4-fold products just prior to heat treatment, it is anticipated that
they would have shown a similar degree of clarification as was found in the samples
after 24 hours of storage at 80F. The data in Table 9 does therefore indicate
the possibility of cloud destruction during processing and handling of concentrates
prior to heat treatment and that this deterioration may not be eliminated by the
subsequent thermal treatment. To prove this another series of folded Pineapple
concentrates will have to be processed and examined.

Cloud stability, initially and after storage at 80F. for 24 hr., in the
Valencia folded juices is reported in Table 10. Samples of these products exam-
ined prior to heat treatment showed no clarification. Also the results indicate
that Valencia juices, pH 3.6, concentrated to 2, 3, or 4-fold products and heat
treated for six seconds at 145F. or above had good cloud stability after storage
for 24 hr. at 800F.


























Citrus Station Mimeo Report 54-3. Florida Citrus Experiment Station and Florida
Citrus Commission, Lake Alfred, Florida. 463a-10/6/53 CDA










TABLE 6


Time-temperature-fold relationships showing the percentage heat inactivation of pectinesterase
in Pineapple orange juice at varying concentrations, pH 3.8


SConcentration 1-fold 2-fold 3-fold 4-fold
Holding time-seconds 12 6 3 12 6 3 12 6 3 12 6 3
_- i _3 6_ -
Temperature i
OF.. C. % ..% % % % % % % %
125 51.5 53.1 47.5 44.5 18.4 .7 127 0110, 9,8 6.5 1,3 0.3
135 57.0 61.8 54.4 48.1 32.1 29.3 25.5 36.0 35.1 242 18.7 9.6 3.7
145 63.0 83.3 67.7 63.2 76.0 53.4 42.5 70.1 s41 35.3 44.1 36.5 28.3
155 68.5 91.1 89.5 79.3 88.4 82.4 77.9 90.4 88.1 74.7 88.5 74.7 67.2
165 74.0o 94.2 93.0 92.4 90.5 88.4 87.4 91.8 91.2 88.8 90.3 88.7 86.6
175 79.5 1 95.4 94.2 93.1 91.8 91.7 89.5 92.7 91.7 91.2 92.0 90.3 89.1
185 85,0 97.2 95.5 94.2 93.7 92.7 91.8 95.6 93.5 92.7 94.9 93.9 93.1
190 88.0 i 98.8 97.2 96.0 97.1 94.7 93.7 99.3 94.3 94.3 97.4 96.5 95.6
195 90.5 .100o.0 98.3 97.2 100.0 97.1 94.8 100.0 97.9 97.1 100.0 98.4 96.5
(---
200 93.5 100. i 98.8 -- 1100.0 97.8 -- 100.0 j 99.3 -- 100.0 98.3
205 96.0 o -- -- l00.0 -- -- 100.0 -- ,100.0 -- -- 100.0
A,-. I .. .. .


Citrus Station Mimeo Report 54-3.
Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida
429J 6/8/53 AHR











TABIE 7


Time-temperature-fold relationships showing the percentage heat inactivation of pectinesterase
in Valencia orange juice at varying concentrations, pH 3.6


Concentration 1-fold 2-fold 3-fold 4.-fold
Holding time-seconds 12 6 3 12 6 3 12 6 3 12 6 3
STemperature S

125 51.55 22.4 17.5 11.9 23.0 18.1 14.9 19.0 16.5 10.6 15.6 13.0 9.2
135 1 57.0 51.41 27.4 16.9 40.3 34.0 26.2 44.8 27.6 21.6 24.5 23.7 16.4
145 63.0 84.7 70.2 54.4 77.0 73.2 58.7 82.4 68.1 54.2 73.9 58.9 52.2
155 68.5 89.1 87.4 84.9 84.2 82.9 81.8 88.7 86.9 84.9 86.5 85.1 83.0
165 74.0 90.0 89.2 87.5 88.9 87.4 85.9 90.9 88.8 87.9 91.9 88.7 87.7
175 79.5 91.7 90.2 89.2 93.0 90.0 88.9 93.8 91.1 90.1 94.4 93.4 92.3
185 85.0 94.3 91.8 90.2 96.0 93.0 91.4 97.2 94.0 92.2 96.5 95.5 94.4
190 8 .0 97.6 94.2 93.5 98.5 96.1 94.5 99.0 97.2 95.1 97.8 96.5 95.5
195 90.5 lO-O 97.6 96.0 100.0 98.5 97.1 100.0 98.9 97.2 100.0 98.9 98.0
200 93.5 100.0 98.4 100.0 98.5 100.0 99.0 00.0 98.9
205 96.0 -- 100.0 -- 100.0 0-- 100.0 - 100.0

Citrus Station Mimeo Report 54-3.
Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida
429k 6/8/53 AHR











TABLE 8


Temperature differentials in a tubular pasteurizer between the juice or
concentrate temperatures and the heating medium temperatures


ii Temperature differential
Concentration 1-fold 2-fold i 3-fold 4-fold
Processing ; j i ,
time-seconds 12 6 3 0.8 12 6 3 12 6 3 12 6 3
Processing temps. i
OFF. j OF F OF.. F. F. O .E. OF, O F OF. OF. F. OF.
125 0.0 0.0 7.0 6.5 0.0 1.0 14.5 0.0 3.5 22.0 0.0 6.0 29.0 0
135 0.0 1.0 9.0 8.5 0.0 1.5 17.0 0.0 4.5 25.0 0.0 7.0 34.0
145 0.0 1.0 10.5 9.0 0.0 2.0 20.0 0.0 5.0 28.0 0.5 9.0 37.0
155 1.0 1.0 10.5 10.0 0.0 2.0 19.5 0.0 5.5 27.0 0.5 10.0 39.0
165 1.0 2.0 11.5 12.0 0.5 3.5 19.5 0.5 6.0 29.0 1.0 10.0 36.5
175 1.0 2.0 11.5 14.0 1.5 4.0 19.5 1.0 6.0 27.0 1.0 9.5 i 39.0
185 1.5 3.5 11.0 14.0 1.5 4.0 17.0 1.5 5.0 25.0 1.5 8.5 36.0
190 1.5 4.0 12.0 13.5 2.0 4.5 17.0 1.5 5.0 28.0 1.5 8.0 37.5
195 1.5 3.5 11.0 13.0 2.0 4.0 19.0 I 1.5 5.0 26.5 2.0 7.0 38.0
200 4.0 13.0 12.0 3.5 180 5.0 26.5 6.5 39.5
205 3.5 13.5 12.0 16.5 28.0 -
210 -- 3. 12.0 - 17.5 -- -- -

Citrus Station Mimeo Report 54-3.
Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida
4291 6/8/53 AIR











TABLE 9


Cloud stability of Pineapple orange juice at varying folds when heat treated in
six seconds and placed at short-term elevated storage temperature


Thermal Degree of clarification1
treatment Initial After 24 hours storage at 800F. (26.50C.)
oF, C. 1-fold 1-fold 2-fold 3-fold 4-fold
Control (not heated) 64 Slight 68 Slight 96 Extreme 95 Extreme 92 Extreme
125 51.5 48 None 49 None 94 Extreme 94 Extreme 91 Extreme
135 57.0 48 None 47 None 93 Extreme 93 Extreme 90 Extreme
145 63.0 1 47 None 46 None 83 Definite 88 Extreme 84 Definite
155 68.5 49 None 50 None 64 Slight 63 Slight 71 Definite
165 74.0 48 None None 59 None 61 Slight 72 Definite
175 79.5 49 None 47 None 58 None 65 Slight 76 Definite
185 85.0 i 47 None 48 None 55 None 63 Slight 76 Definite
190 88.0 47 None 45 None 53 None 63 Slight 78 Definite
195 90.5 46 None 4! 4 None 52 None 61 Slight 76 Definite
200 93.5 46 None .: 45 None 51 None 60 Slight 78 Definite
1 Clarification measured by percentage light transmission of centrifuged reconstituted juice using 10 amm.
rectangular cell in Lumetron colorimeter with filter No. 730. Degree of clarification: 0-595 = None;
60-69% = Slight; 70-84% = Definite; 85-100% = Extreme.


Citrus Station Mineo Report 54-3.
Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida
429m 6/9/53 AHR











TABLE 10


Cloud Stability of Valencia-orange juice at varying folds when heat treated in
six seconds and placed at short-term elevated storage temperature


Thermal Degree of clarification1
treatment ____ Initial After 24 hours storage at 800F. (26.5C.)
o, 0. 1-fold 2-fold 3-fold 4 fold 1-fold 2-fold 3-fold 4-fold
Control (not heated) 53 None 51 None 53 None 47 None 159 None 73 Definite 91 Extreme 80 Definite
125 51.5 46 None 46 None 55 None 47 None 53 None 63 Slight 89 Extreme 77 Definite
135 57.0 46 None 45 None -50 None 46 None 51 None 57 None 86 Extreme 71 Definite
145 63.0 45 None 44 None 50 None 45 None 48 None 47 None 67 Slight 53 None
155 68.5 45 None 45 None 49 None 44 None 47 None 46 None. 56 None 46 None
165 74.0 44 None 43 None 48 None 44 None 46 None 45 None 55 None 47 None
175 79.5 43 None 43 None 49 None 43 None None 4 e 55 one 47 None
185 85.0 43 None 42 None 49 None No4ne 44 None 42 None 52 None 45 None
190 88.0 42 None 42 None 47 None 43 None None 42 None 48 None 46 None
195 905 42 None 41 None 49 None 43 None 43 None 41 None 49 None 44 None
200 93.5 41 None 41 None 49 None '43 None 42 None 41 None 49 None 1.45 None
1 Clarification measured by percentage light transmission of centrifuged reconstituted juice using 10 mm.
rectangular cell in Lumetron colorimeter with filter No. 730. Degree of clarification: 0-59% = None;
60-69% = Slight; 70-.8. = Definite; 85-100% = Extreme.
Citrus Station Mimeo Report 54-3.
Florida Citrus Experiment Station
and Florida Citrus Commission,
Lake Alfred, Florida
429n 6/9/53 AHR




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