Group Title: Citrus Station mimeo report - Florida Citrus Experiment Station ; CES 68-8D
Title: Current status of recovery, characteristics, and use of orange essence
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 Material Information
Title: Current status of recovery, characteristics, and use of orange essence
Series Title: Citrus Station mimeo report
Physical Description: 5 leaves : ; 28 cm.
Language: English
Creator: Wolford, R. W
Citrus Experiment Station (Lake Alfred, Fla.)
Florida Citrus Commission
Publisher: Citrus Experiment Station :
Florida Citrus Commission
Place of Publication: Lake Alfred FL
Publication Date: 1967
Subject: Essences and essential oils -- Florida   ( lcsh )
Orange products -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Statement of Responsibility: R.W. Wolford ... et al..
General Note: Caption title.
General Note: "450-10/12/67-RWW."
 Record Information
Bibliographic ID: UF00072452
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 76804273

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Florida Citrus Commission and
Citrus Experiment Station CES 68-8D
Lake Alfred, Florida. 450-10/12/67-RWW


R. W. Wolford, C. D. Atkins, M. H. Dougherty,
J. A. Attaway, and M. A. Ismail

Florida Citrus Commission
Lake Alfred, Florida

Flavor research conducted at this laboratory over the past several years
has been concerned largely with isolation and identification of volatile chemi-
cal components which contribute to the flavor and aroma of citrus juices. The
results of these investigations leading to a characterization of the individual
citrus juice flavors have been well documented through presentations at the
annual Citrus Processors' Meetings, national and local journals, and through
regular monthly and annual reports.

Certainly of paramount importance to any achievements in these investi-
gations concerning the flavor of orange juice, in particular, has been the
ability to affect removal and recovery of volatile aroma-flavor essences from
the freshly extracted juices for subsequent study. During the past four years
considerable emphasis has been placed on the design and development of systems
for essence recovery to be applicable to commercial operation.

This paper will discuss the current status of the recovery of citrus juice
essences using the FCC-CES system. In addition, some of the characteristics of
the recovered orange essences and the employment of these essences for flavor
improvement of frozen concentrated orange juice and other processed citrus juice
products will be considered.

The principles of removal and subsequent concentration of essences from
citrus juices, employing the vacuum system described at the 1966 Citrus Process-
ors' Meeting, were tested in commercial operation during the 1966-67 season.
Through an agreement of understanding,the FCC-CES essence recovery system was
installed at Pasco Packing Company and the first operation was started in late
December 1966. Only minor corrections in the system were required to place it
in continuous operation. However, to meet the requirements for handling the
increased vapor load on a continuous operational basis, it was necessary to
modify the Freon cooled condensing system. The first Freon condenser was changed
to provide a flooded cooling system in place of the gaseous system used previ-
ously in the pilot plant and the early stages of the commercial .testing. This
modification provided an equalized temperature throughout the condenser and
permitted optimum regulation for improved vapor recovery. The second Freon con-
denser was maintained as a gaseous system and was operated at -100 to -200 F. at
all times. Experimentation at several cooling temperatures on the first conden-
ser provided the basis for a desirable compromise between 360 and 400 F. on the
condensing surface. This resulted in a higher volume of recovered essence con-
taining 50,000 to 60,000 ppm COD. It, also, increased the yield of recoverable
essence from 4.0 to 10.6 gal./1000 gal. raw juice.

During the six months period of operation, this system affected removal of
70 to 80% of the available volatile flavor content from the juices. Recovery
efficiencies of 55 to 62% overall and up to 79% of the total amount of volatile
flavor substances in material removed from the juice were achieved.

Listed in Table 1 are some average data obtained using the FCC-CES essence
recovery system in the commercial testing program for periods of operation of
approximately 20 hr./day, 5 days/week.

Table 1

Average Range
Juice feed rate 111 gal./hr. 80-127 gal./hr.

Essence volume 1 gal./hr. 0.6-1.3 gal./hr.

COD values2
Feed juice 580 ppm 360- 800 ppm
Stripped juice 117 60- 180 "
Individual essence samples3 27,080 12,500-45,500 "
Corrected for Brix change at outlet to evaporator.

For period of operation.
3 By day or barrel.

During the last month of operation 10 drums of orange essence from juices
containing in excess of 800 ppm COD yielded an average concentration of 58,250
ppm COD.

The testing of the FCC-CES essence recovery system under conditions of
commercial operation was considered successful. Sufficient data were obtained
to corroborate the operational data from pilot plant batch operations conducted
at the Citrus Experiment Station and reported at the 1966 Citrus Processors'
Meeting. As a result of these tests and the quality of the recovered orange
essences, a commercial essence system was designed, employing the basic con-
cepts of the FCC-CES system, and placed in operation by Pasco Packing Company
during the 1966-67 season.

The aroma and flavor of orange juice is recognized as being comprised of
an extremely complex and delicately well proportioned mixture of many chemical
compounds. Therefore, orange essence should contain the essential characteris-
tics of the juice from which it is obtained. This fact becomes exceedingly
important in the consideration of the use of recovered essence in flavor im-
provement of frozen concentrated orange juice.

The characterization of the flavor of orange juice through the isolation
and identification of volatile flavor compounds has received major emphasis in
this laboratory, the USDA laboratories, and others for several years. Identi-
fication of over 100 compounds in recovered orange essences and oils has been
accomplished employing the latest instrumental methods accompanied by chemical
methods of analysis and identification of organic compounds. Cumulatively,
these research efforts have provided a wealth of knowledge pertaining to the
aroma and flavor of orange juice. Yet there remains a wide area of unknown
factors regarding essential flavor characteristics of orange juices, processed
products, as well as recovered essences.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/12/67-RWW

In a search for applicable methods to assess quality of recovered essences
as related to fresh orange juice and to provide a basis for its addition to
frozen concentrated orange juice or other juice products, several methods of
analysis were employed. Among these were the Chemical Oxygen Demand (COD) test
employed as a measure of volatile water-soluble compounds as reported by
Dougherty (1), and the methods of Attaway, et al. (2) for determination of oxy-
genated terpenes of the general formula CIoHl80, saturated aldehydes as octanal,
and unsaturated aldehydes as citral.

Examination of essence samples from seven
two months of operation in the commercial test
results shown in Table 2.

drums composite during the last
program provided the analytical

Table 2
COD ClOH180 Octanal Citral
Sample # ppm ppm ppm ppm
1 28,750 120 400 14.0
2 45,500 100 374 24.0
3 52,500 124 840 17.6
4 58,000 132 492 31.6
5 60,000 132 458 30.0
6 67,000 155 540 37.7
7 68,000 148 688 22.0

An attempt was made to relate the results of these analyses and translate
them into some usable criteria for flavor evaluation. Simple mathematical
ratios between the C10H180 values and the two aldehyde values show a relation-
ship of reasonable consistency exclusive of the concentration factors as measured
by the COD method. Table 3 shows the respective ratios for each of the seven
essences analyzed.

Table 3
COD C10H180 ClOH180 Octanal
Sample # ppm Octanal Citral Citral
1 28,750 0.30 0.17 0.035
2 45,500 0.28 0.24 0.065
3 52,500 0.15 0.14 0.022
4 58,000 0.27 0.24 0.064
5 60,000 0.29 0.25 0.066
6 67,000 0.29 0.24 0.066
7 68,000 0.22 0.15 0.032

The Cl0HI80/octanal ratios showed the least amount of variability throughout the
range of concentrations. With the exceptions of the 0.15 ratio for sample # 3,
ratios of 0.22 to 0.30 between these two chemical classifications were obtained
for these orange essences recovered from commercially extracted juices. A simi-
lar relationship calculated for several orange essence samples obtained using the
pilot plant essence system at the Citrus Experiment Station during the 1965-66
season on selected orange varieties showed the CloHI80 / octanal average ratios
for 'Pineapple' orange essence to be 0.25 and for 'Valencia' essence to be 0.32.
Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/12/67-RWW

This ratio calculation was also applied to commercial concentrated orange
juices packed during the 1966-67 season. Sixty-seven samples of frozen con-
centrated orange juices were collected from seven commercial plants between
December 15, 1966 and June 15, 1967. These samples were analyzed initially for
their volatile water-soluble contents, oxygenated terpenes, saturated and un-
saturated aldehyde contents. The maximum and minimum CloHi80/octanal ratios
and the average ratios for the total samples analyzed from each plant are shown
in Table 4.

Table 4
Concentrate No. of Flavor ClJ0H80/Octanal
plant samples grade Max. Min. Av.
1 8 7.5 0.32 0.29 0.30
2 11 7.4 0.30 0.27 0.28
3 7 6.8 0.17 0.13 0.16
4 12 6.5 0.20 0.17 0.19
5 8 7.7 0.35 0.25 0.26
6 9 7.6 0.57 0.23 0.27
7 12 7.9 0.32 0.22 0.27

Since these samples were collected semi-monthly, the maximum and minimum
ratios probably reflect normal variations in processing, as well as, the can to
can variations usually encountered. Although a statistical analysis of these
data was not made, certain trends are indicated. Comparison of the average
ratios with the average flavor grades indicates that those samples receiving
grades of 7 to 8 had an average ratio of CloHl80 / octanal of 0.26 or higher.
The lower values indicate a higher saturated aldehyde content in the reconsti-
tuted juices. Flavor grades and ratios between these classes of compounds
were also determined on the same samples after 3 months storage at -8F. A
similar trend in ratio of ClOH180 / octanal was shown except that an average
minimum ratio from 0.28 to 0.30 for those samples given the better flavor grades
was indicated.

Comparisons between the ClOHI80 and octanal contents of the commercial fro-
zen concentrated orange juices in Table 4 were compared with fresh juices. The
minimum and maximum values for these two classes of compounds found in reconsti-
tuted concentrates and the fresh juices are shown as a range of values in Table
5. The ClOH180 / octanal ratios are shown as maximum and minimum values obtained.

Table 5

Sample and

Commercial concentrate
(67 samples)
(5 samples)
(4 samples)
(8 samples)









Max. Min.









See footnotes on following page.

Results from initial samples Table 4.

2 Sampled 11/28/66 through 1/24/67.

3 Sampled 11/28/66 through 2/13/67.

Sampled 3/ 2/66 through 4/24/67.

From the results obtained in this preliminary study, it was indicated that
a relationship between two of the major chemical classifications, constituting
orange aroma and flavor, might be developed as a criterion or characteristic for
use in flavor evaluation of orange juices, essences, and processed products. The
ratio of oxygenated terpenes (ClOHI80) to saturated aldehydes (octanal) indicated
that the FCC-CES orange essences compared quite well in this characteristic with
that of reconstituted commercial orange concentrates. Therefore, the use of
these essences for flavor add-back to frozen concentrated orange juices should
provide, essentially, an increased intensity of aroma and flavor without alter-
ing the ClOHl80/octanal ratio in the product.

Employing these characteristics in comparison of commercial concentrates
with fresh juices, it appeared that a higher ratio of C10H180/octanal is re-
quired in concentrates than in fresh juice for good flavor acceptance, Possibly
a lower saturated aldehyde content is required for orange concentrates than for
fresh juice. A comparison between the FCC-CES orange essences and the fresh
juices based on the ratio of ClOH180 / octanal in each indicates a higher ratio
in the essences. Unfortunately, the 'Valencia' orange juices were analyzed only
through April, while the essences employed in this study were recovered in late
May and June, 1967, making a direct comparison impossible.

The development of methods for analysis of other chemical classifications
contributing to the aroma and flavor of orange juices and the determination of
additional chemical relationships may provide a sound approach to objective
flavor evaluation for purposes of quality control.


1. Dougherty, M. H. 1966. A method for measuring the water soluble volatile
constituents of citrus juices and products. J. Food Sci. In Press.

2. Attaway, John A., Richard W. Wolford, Marshall H. Dougherty, and George J.
Edwards. 1967. Methods for the determination of oxygenated terpenes,
aldehyde, and ester concentrations in aqueous citrus essences. J. Agr.
Food Chem. 15, 688-692.


The authors wish to express appreciation to Pasco Packing Company for their
cooperation and assistance in conducting the commercial testing of the FCC-CES
pilot plant essence recovery system; also, to Louise Cherry and Kay Nettles
for conducting the many routine chemical analyses.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida. 450-10/12/67-RWW

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