Group Title: Citrus Station mimeo report - Florida Citrus Experiment Station - CES 67-7
Title: A Vacuum system for removal and concentration of citrus juice essences general description and operational data
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 Material Information
Title: A Vacuum system for removal and concentration of citrus juice essences general description and operational data
Series Title: Citrus Station mimeo report
Physical Description: 3 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: 1966
Subject: Citrus juices -- By-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: "400-10/4/66-RWW."
 Record Information
Bibliographic ID: UF00072472
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 76752278

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Florida Citrus Commission and
Citrus Experiment Station CES 67-7
Lake Alfred, Florida. 400-10/4/66- RWW

A Vacuum System for Removal and Concentration of Citrus Juice Essences
General Description and Operational Data

R. W. Wolford, C. D. Atkins, M. H. Dougherty, and J. A. Attaway
Florida Citrus Commission
Lake Alfred, Florida

The principle of removal and subsequent concentration of essences from
citrus juices, employing the vacuum system to be described, is based on
vaporazation of a portion of the water in the juice, accompanied by vapor en-
trainment of the essence or aroma bearing components. Removal and concentration
of the essence is then achieved by reflux and separation from the condensed water
vapor. This essence removal is an exacting procedure carried out, under the best
sanitary conditions, in equipment constructed of 304 stainless or its equivalent.
It has been accomplished, more generally, in a multi-stage vacuum system from
single-strength juices following normal juice extraction and finishing operations.

Temperature and pressure are adjusted to an optimum level for obtaining the
most efficient removal of a good flavored essence from the juice. Both separation
and concentration of the volatile water- and oil-soluble components are affected
simultaneously to yield an appropriate concentration of essence for add-back to
concentrated or single-strength juice products. Refrigerated condensers prevent
any significant loss of volatiles from the vertical condensing and concentrating
heat exchangers. Removal and concentration of the essence usually require less
than 20 seconds. However, the juice is in contact with heat in the multi-stage
system only a fraction of the time required for the cycle. When the juice is
intended for concentration to a higher Brix ranging from 550 to 720, direct
transfer of the juice to the evaporator, at an appropriate temperature for multi-
stage or multi-effect units, is included as an integral part of the cycle.

The following is taken from a summary of details on the experimental essence
recovery systems, installed at the Citrus Experiment Station (CES), as presented
in monthly reports to the Florida Citrus Commission (FCC) and CES during the
1964-65 and 1965-66 seasons. Single and multi-stage essence recovery systems
have been built and tested as a part of processing research. A single-stage unit
consists of the following items (Table 1): (1) positive inlet pump, (2) plate
type or infusion type heater, (3) vapor liquid separator, (4) vertical tubular
heat exchanger, (5) condensate receiver tank, (6) discharge pump, (7) refriger-
ated essence vapor heat exchanger, (8) refrigeration unit and (9) vacuum pump of
either mechanical, steam jet, or hydrovactor type. Ultimately, a multi-stage
system was installed, through multiple connections and series flow, consisting
of five single-stage units. The two types of heaters indicated in (2) are em-
ployed in the FCC-CES 5-stage system. The APV Paraflow Plate Heater serves as
the heat stabilizer and furnishes heat to the first-stage vapor-liquid separator.
Thereafter, four Ultratherm infusion heaters are used between the successive
stages. The choice of this type of heater was made to achieve nearly instantane-
ous heat and maintain a rapid throughput for protection of quality in the juice,
which was stripped of essence and pumped to the evaporator. The number of re-
frigerated essence vapor heat exchangers required to handle the vapor load and
provide efficient condensation of product remains a matter of choice. The
FCC-CES essence recovery system includes, in addition to the above, a second
backup condenser operated at approximately -200F., while the main refrigerated
condenser for product recovery is operated at approximately 350F.

Each piece of equipment employed in the system is produced by a commercial
manufacturer and, in general, has much more capacity than is needed for this
particular small scale operation. Larger sizes are available from equipment
manufacturers. The numbers of items included in the system are shown in Table 1,
column 2, under the cost breakdown for the single- and five-stage systems.
Column 1, under the same heading, shows the cost per individual item in a single-
stage and column 3 shows the relative cost for each item of equipment in a
single-stage when used in a 5-stage system. Column 4, under same heading, Table
1, shows the approximate cost for a total of five stages in a multi-stage system
as determined by multiplying column 1 by column 2. Item 2a used in the 5-stage
system is calculated as 4 items at $1490.00 each as shown in column 3. The total
estimated aggregate cost of $23,610.00 is shown in column 4. The addition of a
backup condenser and a second Freon refrigeration unit, same as items 7 and 8
would bring the aggregate cost to $25,555.00. These costs do not include electri-
cal, steam or water supply, stainless steel liquid or vapor lines, steel supporting
framework, building and installation. Operational costs for steam and electrical
power require individual plant cost figures for these items.

The following serves as a brief description of a typical essence recovery
operation, starting with freshly extracted and deaerated orange juice. To pre-
pare 0.58 gal. of 100-fold essence in the 5-stage unit required, by calculation,
225 to 240 lbs. steam per hour at 40 psig, not including steam for the steam jet
vacuum pump. Also, 22 gal. of 800F. water per min. at 45 psig was used for
cooling the vertical tubular heat exchanger. At a feed rate of 2 gal. per min.,
the water removed from 120 gal. of juice was calculated to be 10.9 gal. or 9.2%
of the total volume of juice through the 5-stage unit. The non-condensables are
removed by steam jet at 26" to 28" vacuum as measured on the final refrigerated
condenser. As mentioned earlier, the feed rate to the system was normally 2 gal./
min. of raw deaerated juice. However, rates of 2-6 gal./min. are well within
the pumping capacity and may be feasible. Pre-treatment of the juice by de-
aeration is not considered to be a requirement.

The following data summarize results showing average yield figures obtained
during the 1965-66 season with the FCC-CES pilot plant 5-stage essence recovery
system. These data are confined to the recovery of volatile components which
contribute to the aroma and flavor of 'Pineapple' and 'Valencia' orange juices.
Entirely satisfactory results have been obtained from tests using 'Hamlin' orange
juice and grapefruit juice. No special effort was made in the selection of fruit
in these operations. Therefore, the fruit used would be considered as grove run.
Normal concentrations of the orange essences ranged between 50,000 and 60,000
ppm volatile water-solubles as measured by the Chemical Oxygen Demand (COD)
test used in these studies. Average yield figures for the 1965-66 season were as
follows: (1) percentage removal of volatile water-soluble aroma and flavor
components from fresh deaerated orange juice by single pass through recovery
system was 70 to 75%; (2) average volume of essence obtained from extracted
orange juice was 5 gal./1000 gal. fresh juice; and (3) concentration of recovered
essence averaged 100-fold relative to fresh juice.

At an average yield of 5.5 gal. of juice per box of oranges, used in these
operations, 198 gal. of juice from 36 boxes of fruit were used to obtain 1 gal.
of essence containing 57,500 ppm volatile water-soluble material. Based on a
volatile water-soluble content of 105 ppm in reconstituted juice from 44.80 Brix
concentrate, the following quantities of this essence would be required to achieve
the four flavor levels shown in Table 2.

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida.
400- 10/4/66 RWW

Table 2
Total volatile water-soluble content Gallons of essence required per
in reconstituted juice (ppm) 1000 gal. reconstituted juice
300 3.39
350 4.26
400 5.14
450 6.00

The volatile water-soluble contents listed are commensurate to the range of
values found in fresh 'Valencia' orange juice during the period of operation.

From these values it may be seen that approximately 0.9 gal. of this partic-
ular essence was required for each 50 ppm increase desired in the final reconsti-
tuted product. The final level desired must be determined by organoleptic
evaluation. It has been shown that when recovered volatiles are added in proper
proportion to concentrate of good quality both the aroma and flavor intensities
can be increased to a satisfactory aroma and flavor level. Further, the amount
of flavor enhancement required is directly related to the quality of the product
to which it is being added.

It is well recognized that proper handling is required in using fresh cut-
back juice. Likewise, the recovery of other more concentrated flavor essences
should not in any way be considered as a so-called by-product operation. Using
the FCC-CES essence recovery system as an example, each of the following steps
should meet the highest standards required in handling freshly extracted juices
for manufacture of frozen concentrated orange juice. Such steps include (1) the
separation of the essence and oil directly from the juice, (2) concentration of
these components, and (3) their final removal from the system.

Since a supply of essence should be obtained under the most favorable
conditions at the lowest possible cost, orange and other citrus juice essences
should be recovered at a time commensurate to both acceptable maturity and
volatile flavor content of the fruit.

It is highly conceivable that an appropriate blend of recovered essences
from juice of more than one variety of fruit will supply the required fresh,
fruity aroma and flavor characteristics to the finished product. Limited test-
ing employing an essence blend consisting of 50% 'Pineapple' essence and 50%
'Valencia' essence supplied the desired characteristics. Such blending
technique would increase appreciably the amount of usable essence add-back
recovered during a processing season.

All of the information and data presented have been obtained under the
conditions of batch operations. The system is now considered to be ready for
testing under commercial conditions, including continuous juice flow. This
will provide for the accumulation of data for commercial development of this
essence recovery system.

Florida Citrus Commission and
Citrus Experiment Station,
Lake Alfred, Florida.
400-10/4/66 RWW

Description and



Type of

Positive pump

(a)Plate type heater
(b)Infusion type heater

3 Vapor liquid separator

4 Tubular water-cooled

5 Condensate receiver

6 Positive pump
7 Freon 12 or 502
refrigerated heat
8 Freon 12 or 502
refrigeration compressor
9 Steam jet vacuum pump

Table 1
Costs of Equipment for Single- or 5-Stage Essence Systems
Approximate dollar costs for equipment
(1) (2) (3) (4)

Tri-Clover PRO-1 1/2
Reeves var. speed
HXC-4APV Paraflow Plate
Ultratherm infusion heater
Lab. Model
Stainless vacuum chamber with
vapor stack

56 sq. ft. stnl. stl. #304, Heat
exchanger size 806
One pass. (48) 3/4" O.D. X 18BWG
Stnl. stl. #304 welded tubes 72"long
Vacuum tank stainless steel
20" diameter X 22" high
Same as No. 1
Same designation as No. 4

3 HP Freon 12
220 volt AC
Ingersoll-Rand Steam Ejector

$ 630







No. of


$ 630


5 1300





Approx. cost







Include only one type heater per single unit.

Total Equipment cost $7,130

$5,020 $23,610

Florida Citrus Commission and
Florida Citrus Experiment Station,
Lake Alfred, Florida.
400- 10/4/66 RWW

Type of

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