United States
Environmental Protection
Agency
Industrial Environmental Research
Laboratory
Cincinnati OH 45268
EPA 600 2 78 206
178
Research and Development
vvEPA
Vibratory Spiral
Blancher-Cooler
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development, U.S. Environmental
Protection Agency, have been grouped into nine series. These nine broad cate-
gories were established to facilitate farther development and application of en-
vironmental technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface in related fields.
The nine series are:
1. Environmental Health Effects Research
2 Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
6. Scientific and Technical Assessment Reports (STAR)
7. Interagency Energy-Environment Research and Development
8. 'Special" Reports
9. Miscellaneous Reports
This report has been assigned to the ENVIRONMENTAL PROTECTION TECH-
NOLOGY series. This series describes research performed to develop and dem-
onstrate instrumentation, equipment, and methodology to repair or prevent en-
vironmental degradation from point and non-point sources of pollution. This work
provides the new or improved technology required for the control and treatment
of pollution sources to meet environmental quality standards.
This document is available to the public through the National Technical Informa-
tion Service, Springfield, Virginia 22161.
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EPA-600/2-78-206
September 1978
VIBRATORY SPIRAL BLANCHER-COOLER
by
John L. Bomben, J. S. Hudson, W. C. Dietrich,
E. L. Durkee, D. F. Farkas
Western Regional Research Center, Science and Education Administration,
U. S. Department of Agriculture, Berkeley, California 94710
and
Richard Rand, J. W. Farquhar
American Frozen Food Institute
McLean, Virginia 22101
Grant No. S-803312
Project Officer
Harold W. Thompson
Food and Wood Products Branch
Industrial Environmental Research Laboratory
Corvallis Field Station
Corvallis, Oregon 97330
INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
-U. S. ENVIRONMENTAL PROTECTION AGENCY
CINCINNATI, OHIO 45268
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DISCLAIMER
This report has been reviewed by the Industrial Environmental Research
Laboratory, U. S. Environmental Protection Agency, and approved for publica-
tion. Approval does not signify that the contents necessarily reflect the
view and policies of the U. S. Environmental Protection Agency, nor does
mention of trade names or commercial products constitute endorsement or
recommendation for use.
ii
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FOREWORD
When energy and material resources are extracted, processed, converted,
and used, the related pollutional impacts on our environment and even on
our health often require that new and increasingly more efficient pollution
control methods be used. The Industrial Environmental Research Laboratory-
Cincinnati (lERL-Ci) assists in developing and demonstrating new and im-
proved methodologies that will meet these needs both efficiently and econo-
mically.
This report presents the results of a two year evaluation of a unique
vegetable blanching and cooling system. Study results indicate that the
vibratory spiral blancher-cooler will significantly reduce the wasteloads
and energy consumption associated with these unit processes. Study results
should be of interest to processors of frozen and canned vegetables, food
process researchers, and manufacturers of equipment for the user industries.
Further information on the project can be obtained by contacting the Food
and Wood Products Branch, Industrial Pollution Control Division, lERL-Ci.
David G. Stephan
Director
Industrial Environmental Research Laboratory
Cincinnati
iii
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ABSTRACT
The objective of this demonstration project was to test the commercial
feasibility of the vibratory spiral blancher-cooler, a newly designed steam
blancher and air cooler that previous small scale tests showed could reduce
the wasteload and energy consumption of preparing vegetables for freezing.
A prototype vibratory spiral blancher-cooler was designed and con-
structed. This unit was installed at a vegetable freezing plant for two
processing seasons. Snap beans and lima beans were tested for both pro-
cessing seasons; a few brief experimental runs with brussels sprouts,
cauliflower and broccoli were done during one season.
The results of these prototype tests showed the following:
1. The unit reduced the hydraulic wasteload of conventional blanching
and cooling by several orders of magnitude and the organic waste-
load by as much as 80%.
2. The steam efficiency of the blancher was 85%, which exceeds by
17 times that measured for a conventional steam blancher.
3. The vibratory spiral blancher-cooler processed over 2000 kg/hr
of snap beans and over 1200 kg/hr of lima beans. Minor equipment
modification would be required to achieve full capacity with
broccoli, brussels sprouts, and cauliflower.
4. It was easy to clean after use. Product leaving the cooler had
microbial counts far below the accepted practice in vegetable
freezing plants.
5. Sensory tests were done only with the snap-beans and lima beans.
Those samples produced by the vibratory spiral blancher-cooler
were judged either equal or superior in flavor and texture to
those conventionally blanched and cooled.
6. Although the operating costs of the vibratory spiral blancher-
cooler were higher than those of a conventional water blancher
and a flume cooler, a doubling of the combined costs of utilities
and waste treatment would make the operating costs of the two
equal.
This report was submitted in fulfillment of Grant No. S-803312 by
the American Frozen Food Institute under the partial sponsorship of the
U. S. Environmental Protection Agency. Work was conducted by the U. S.
iv
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Department of Agriculture Western Regional Research Center under contract
to the American Frozen Food Institute. This report covers the period
July 15, 1974 to January 17, 1977.
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CONTENTS
Forword ill
Abstract iv
Figures vii
Tables viii
Acknowledgments ix
1. Introduction 1
2. Conclusions 3
3. Recommendations 4
4. Experimental Procedures 5
Prototype Design 5
Pilot Plant Operating Procedures and Production Line
Measurements 12
Pilot Plant Operating Conditions 14
5. Results and Discussion 22
Analysis of Prototype Design and Operations 23
Material Balances and Wasteloads 27
Product Quality 30
Effluent Generation and Steam Consumption of Blanchers . . 36
Cost Estimates 38
References 44
Appendix 46
vii
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FIGURES
Number Page
1 Schematic diagram of vibratory spiral blancher-cooler 6
2 Drawing of vibratory spiral blancher-cooler with cooler
in up-flow operation 7
3 Photograph of vibratory spiral blancher-cooler with cooler
in up-flow operation 8
4 Drawing of vibratory spiral blancher-cooler with cooler
in down-flow operation 9
5 Photograph of vibratory spiral blancher-cooler with cooler
in down-flow operation .......10
6 Air velocity distribution over cooler spiral conveyor 26
viii
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TABLES
Number Page
1 Operating Conditions for Snap Beans 15
2 Operating Conditions for Lima Beans 18
3 Operating Conditions for Brussels Sprouts, Cauliflower and
Broccoli 20
4 Yield, Solids Loss and Liquid Wasteload for Snap Beans 28
5 Yield, Solids Loss and Liquid Wasteload for Lima Beans 29
6 Yield, Solids Loss and Liquid Wasteload for Brussels Sprouts,
Cauliflower and Broccoli 30
7 Means of Yields, Solids Losses and Liquid Wasteloads with 95%
Confidence Limits 31
8 Total Aerobic Plate Counts on Vegetables Leaving Cooler 32
9 Sensory Evaluation of Snap Beans and Lima Beans by Duo-Trio Test. . 33
10 Chemical Analyses of Vegetables 35
11 Wasteloads Produced by Different Blanching Techniques 37
12 Energy Use in Blanching 38
13 Capital Investment for Blanchers and Coolers 39
14 Cost of Blanching and Cooling for Freezing 41
15 Cost of Blanching Without Cooling for Vibratory Spiral Blancher
and Water Blancher 43
IX
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ACKNOWLEDGMENTS
The authors wish to express their appreciation to Harold Thompson, EPA
Project Officer, for his guidance on this project. In addition, we would
like to thank personnel of the American Frozen Food InstituteJoanne Cox,
Elaine Carter, Jean Bohannon and Ray McHenrywho provided administrative
help. John Swartz, Chris Drasbek, Anne Whitney and Joel Weaver, temporary
employees of the American Frozen Food Institute, served as technicians in
setting up and testing the pilot plant. We also wish to thank those person-
nel of Patterson Frozen Foods and Tom Rumsey of the Western Regional Research
Center who provided periodic assistance for this project. The equipment was
constructed by the Vibrating Equipment Division of the Rexnord Corporation.
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SECTION 1
INTRODUCTION
A major conclusion of reports on the wasteload of vegetable processing
is that the blanching operation produces a large percentage of a vegetable
processing plant's wasteload (Weckel, et al., 1968; NCA, 1971; Rails and
Mercer, 1973; Soderquist, 1975). The work presented in this report describes
a technique that reduces the wasteload from both blanching and the subsequent
cooling of vegetables. It accomplishes this waste reduction with a large
savings in the use of steam and with a design requiring less floor space
than a conventional steam blancher.
The prototype vibratory spiral blancher-cooler, whose design and perform-
ance is described here, is a demonstration of a series of developments of
the work done at the Western Regional Research Center on steam blanching and
cooling of vegetables before freezing (Brown, et al., 1974; Bomben, et al.,
1975). Each of these developments was tested at the Western Regional
Research Center to the small pilot plant stage. The prototype vibratory
spiral blancher-cooler pilot plant incorporated all of these developments,
and it was of adequate capacity to demonstrate the suitability of these
concepts for use in the commercial processing of frozen vegetables.
The use of vibratory conveyors for steam blanching was developed to
reduce the size and improve the heat efficiency of steam blanchers (Brown,
et al., 1974). The spiral vibratory conveyor allowed for a more compact
design than did the conventional belt conveyor in steam blanchers. In
comparison to water blanchers, steam blanchers are large and have a low
thermal efficiency. The lower wasteload of steam blanching as compared to
water blanching (Rails and Mercer, 1973; Lund, 1974) has not been sufficient
for most processors to justify its use in place of water blanching. The
thermal efficiency of blanchers has not been a subject of much interest
until the recent concern about the cost and availability of energy sources.
Using steam blancher condensate as a spray during air cooling was
another development incorporated into the vibratory spiral blancher-cooler.
This technique reduced the wasteload of both blanching and cooling (Bomben,
et al., 1975). By using air instead of flume cooling, the hydraulic waste-
load of cooling was reduced enormously, and the organic wasteload produced
by the leaching of solids in the flume was eliminated. By using the steam
blancher condensate as a spray during air cooling, the wasteload of both
blanching and cooling was reduced to the unevaporated and unabsorbed liquid
leaving the cooler.
The technique of Individual Quick Blanching (IQB) was included in
the vibratory spiral blancher-cooler since it gave an additional means of
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reducing the size of the blancher (Lazar, et al., 1971). The heating and
holding technique in addition provided uniform blanching of vegetables.
The prototype vibratory spiral blancher-cooler was installed and tested
at a frozen vegetable plant (Patterson Frozen Foods, Patterson, California)
from August, 1975 to January, 1977. Snap beans and lima beans were tested
during two processing seasons. A few brief runs were made with brussels
sprouts, cauliflower and broccoli during the second processing season.
Although the tests described in this report apply to frozen vegetables,
the blancher (without the cooler) could be used in the vegetable canning
industry.
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SECTION 2
CONCLUSIONS
The vibratory spiral blancher-cooler was able to blanch and cool vege-
tables at a rate far exceeding its design capacity of 900 kg/hr for snap
beans. Snap beans were blanched at over 2000 kg/hr and lima beans were
blanched at 1200 kg/hr. Modification of the equipment would be required to
achieve full capacity for broccoli, brussels sprouts and cauliflower. The
vibratory cooler was operated in two different modes; vegetables were either
conveyed up or down. Higher capacities were achieved with vegetable flowing
down the cooler. With product moving down the cooling vibratory spiral, snap
beans, lima beans, brussels sprouts, cauliflower and broccoli could all be
processed. With product moving up the cooling spiral consistent product flow
could be achieved only with snap beans.
The wasteload produced by the vibratory spiral blancher-cooler (1 L/kkg)
and 0.9 kg BOD/kkg lima beans) was much less than that produced by conven-
tional blanching and cooling (1000 L/kkg and 4.4 kg BOD/kkg lima beans). The
steam efficiency of the vibratory spiral blancher (85%) was much higher than
that measured on a production line steam blancher (5%) and those reported
for other blanchers (27 - 60%).
Sensory tests of snap beans and lima beans produced by the vibratory
spiral blancher-cooler showed them to be either better or the same in flavor
and texture as those produced in a conventional blancher on the production
line. Total aerobic counts made on snap beans and lima beans leaving the
vibratory spiral cooler were considerably lower than the limits accepted
by sanitary practice in the vegetable freezing industry.
The low capital investment required by water blanching makes its
cost significantly less than other blanching techniques. A doubling of the
combined cost of energy and wastewater treatment would make the cost of
blanching and cooling with the vibratory spiral blancher-cooler equal to
that of a water blancher and flume cooler. When comparing blanching alone
(without cooling), water blanching remained the lowest cost method, but
again, doubling of the combined cost of energy and wastewater treatment
would make the cost of the vibratory spiral blancher equal. The cost of
blanching with the vibratory spiral blancher was less than that of either
the hydrostatic steam blancher or hot-gas blancher.
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SECTION 3
RECOMMENDATIONS
Since the vibratory spiral blancher-cooler tested in this project was
large enough to be representative of a typical full-scale production unit,
there is no need to test the design on a larger scale. Scale up to a larger
size can be readily accomplished; designs with capacities 5 and 10 times
that of the pilot plant are available from the manufacturer of the pilot
plant. However, it is recommended that any private company considering the
installation of a full-size vibratory spiral blancher-cooler utilize the
pilot plant constructed under this project to obtain design and production
data for its particular use.
Although the results of the project indicate that broccoli, brussels
sprouts and cauliflower can be processed with this equipment, full capacity
for these vegetables would require an increase in the size of the holder and,
in the case of broccoli, an increase in the sizes of the inlet and discharge
cross-sections. Before a full size unit for these vegetables can be designed,
the exact dimensions of these changes need to be determined by testing the
vegetables on a modified prototype.
All the work done in this project was aimed at preparing vegetables
for freezing, and hence cooling was always used. In blanching for canning,
cooling is an unnecessary step, but the advantages of compactness and high
steam efficiency for the vibratory spiral blancher still have applicability
for canning. In addition, blanching effluent could be entirely eliminated
if it were suitable for use as a brine for canning vegetables. Thus, it is
recommended that the vibratory spiral blancher be tested in a vegetable
canning plant and that the use of the blancher condensate as a canning brine
be evaluated.
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SECTION 4
EXPERIMENTAL PROCEDURES
Prototype Design
The prototype pilot plant, which is shown schematically in Figure 1,
was designed with a 0.91 kkg/hr (one ton per hour) capacity based on a con-
veyor loading of 4.9 kg/m (one pound/ft ), and a bulk density of 641 kg/m
(40 Ib/ft ) for the vegetables. The equipment was constructed using a stan-
dard design for vibratory spiral conveyors. The pilot plant occupied a floor
area of 3.7 by 3.2 m (12 ft by 10-1/2 ft) and it had a shipping weight of
8.6 kkg (19000 Ibs).
The pilot plant was operated in two different modes. Figures 2 and 3
show the pilot plant as it was operated during the 1975 vegetable processing
season with product moving up the cooling spiral. Figures 4 and 5 show the
pilot plant as it was operated during the 1976 season with product moving
down the cooling spiral. The movement of product up the cooling spiral gave
a design of less height, 4.2 m (13 ft - 11 in.), versus that, 6.1 m (19 ft -
11 in.), for product movement down the cooling spiral. The down-flow arrange-
ment was necessary since the vibration could not move some vegetables upward.
The pilot plant consisted of six units: feeder, heater, holder, cooler,
air blower with filter, and condensate spray system. These units are indica-
ted in Figure 1, and they are shown in more detail in Figures 2, 3, 4 and 5.
For operation with the up-flow cooler, the feeder-elevator consisted of
an inclined, cleated (3.8 cm; 1-1/2 in.) rubber belt conveyor 30.5 cm wide by
7.6 m long (12 in. by 25 ft), a 746 W (1 hp.) variable speed drive and a
1.4 m (50 ft ) feed bin. For operation with the down-flow cooler, the above
feeder was used as an elevator to the feed bin (0.057 m ; 2 ft ) of a smaller
inclined, cleated (3.8 cm; 1-1/2 in.) belt conveyor 20.3 cm wide by 3.0 m
long (8 in. by 10 ft) driven by a 746 W (1 hp) variable speed electrical
drive.
The heater was a vibratory spiral enclosed in a double wall insulated
[2.5 cm (1 in.) air spacing] housing having one access door (Figures 3 and
4). At the bottom of the housing there was a 5.1 cm (2 in.) diameter drain
for condensate from the inside walls. The spiral conveyor, consisting of
three 30.3 cm (11-15/16 in.) wide flights, had a 30.5 cm (12 in.) pitch.
Steam was distributed through the central tube, which had twelve 1.9 cm
(3/4 in.) holes 76.2 cm (30 in.) apart and 7.6 cm (3 in.) above each flight
of the spiral conveying surface. The spiral and housing were made of stain-
less steel (Type 304, No. 2B finish on spiral and No. 3 finish on housing).
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RAW
VEGETABLES
FEEDER
STEAM
HEATER
AND HOLDER
AIR
o
EFFLUENT
COOLER
BLANCHED
& COOLED
VEGETABLES
CONDENSATE SPRAY SYSTEM
Figure 1. Schematic diagram of vibratory spiral blancher-cooler.
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3.66m
A\ V STEAM
v * X INLET
DISCHARGE
FROM HOLDER
Figure 2. Drawing of vi"bratory spiral blancher-cooler with cooler in
up-flow operation.
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Figure 3. Photograph of vibratory spiral blancher-cooler with cooler in
up-flow operation.
8
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3.66m
DISCHARGE
FROM HOLDER
6.10m
DISCHARGE
Figure h. Drawing of vibratory spiral "blancher-cooler with cooler in
down-flow operation.
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Figure 5. Photograph of vibratory spiral tlancher-cooler with cooler in
down-flow operation.
10
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There were two feed spouts; one was at the beginning of the top flight and
the other was at the beginning of the middle flight. Only the top feed spout
was used in the experiments described in this report. Two 1119 W (1-1/2 hp)
electrical motors (220 V, 900 rpm), which had eccentric weights on their
doubly extended shafts and which were mounted at 45° to the horizontal,
vibrated the spiral at a frequency of 890 cpm. The drive motor mounting was
suspended by cables and springs to isolate the vibration from the structural
framework. The amplitude of vibration could be varied up to 9.5 mm (3/8 in.)
in ten steps by shifting the position of the eccentric weights on the motors.
The direction of vibration moved the vegetables down the heater spiral, and
the amplitude of vibration determined their conveying velocity.
The vegetables leaving the heating spiral dropped into the holder
(Figures 2 and 3), which was a horizontally vibrating conveyor 1.5 m long x
0.3 m x 0.3 m (5 ft x 1 ft x 1 ft) enclosed by double wall insulation [2.5 cm
(1 in.) air space]. At the bottom of the holder near the feed end there was
a 2.5 cm (1 in.) drain for the condensate produced by the vegetables in the
heater spiral. A screen (50% open area, 5 mm diam. holes) of perforated
stainless steel was installed over the drain to prevent it from being plugged
by vegetables. The holder was vibrated at 890 cpm by a 1119W (1-1/2 hp)
electrical motor (220 V; 900 rpm) with a doubly extended shaft on which two
series of four eccentric weights were mounted. By changing the number of
weights, the amplitude of vibration could be varied up to 6.4 mm (1/4 in.).
In addition, the holder motor was equipped with a timer that controlled the
period the motor was on and off to get a desired residence time. The vibra-
tion was isolated from the supporting framework by suspending the holder
with cables and springs.
The blanched vegetables leaving the holder were discharged to the
cooler, where the vegetables moved up or down the vibrating spiral conveyor,
depending on the mode of operation. The cooler spiral conveyor (Figures 4
and 5) had the same design as the one in the heater except that it had
6-1/2 flights. The drive unit for the cooler was of the same design as
that in the heater, and by rotating the angle of mounting by 90° the product
flow could be changed from up-flow to down-flow. Air was distributed
through the central tube over the product through twelve 2.5 cm (1 in.)
holes 76.2 cm (30 in.) apart and 8.9 cm (3-1/2 in.) above each flight of the
spiral conveying surface. The housing for the cooler was constructed of
stainless steel (Type 304, No. 3 finish). It had two access doors, and it
had a 5.1 cm (2 in.) drain leading to an effluent collection tank.
The blower (Buffalo Forge, No. 40 MW) used for moving air over the
product in the cooler had a rating of 150 m /min. (5300 ft /min.) of air at
21°C (70°F) and a presure of 15.2 cm (6 in.) of water. A filter (Conti-
nental No. 3P439M Side Access Conopac, 90% efficiency) was installed at the
inlet of the blower. A damper on the outlet of the blower was used to
control the amount of air flow.
The condensate spray system consisted of a pump (Waukesha Sanitary Pump,
No. 10, capacity = 11 L/min.), approximately 4.6 m (15 ft) of 2.5 cm (1 in.)
diameter stainless steel sanitary pipe and four stainless steel nozzles
(Spraying Systems Co., Unijet Nozzle No. 2503). Condensate was sprayed on
11
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the product in the cooler at the first, third, fifth and sixth flights. The
condensate from the drain in the holder was filtered either through three
layers of cheesecloth or a 100 mesh stainless steel screen to prevent parti-
cles from clogging the nozzles.
Temperatures at the inlet and outlet of the heater, holder and cooler
were measured by thermocouples and recorded on a multi-point temperature
recorder. A water manometer measured the pressure at the blower, and the
amount of air flow was determined from the blower performance curve supplied
by the blower manufacturer. A rotameter [Fischer-Porter, Model No. 10A1152,
100% of scale = 5.6 m /min. (199 scfm) of air], which had been previously
calibrated by condensing and weighing the steam flowing through it, was used
to measure the flow of steam to the heater. Condensate was removed from the
steam supply by passing it through a purifier (V. D. Anderson Co., Model
LC-150). A pressure regulator (Spence Engineering Co., 3/4 in. Type ED)
maintained a constant pressure at the throttling valve installed in the steam
line after the rotameter. The relative humidity of the air at the inlet of
the filter on the blower was measured with an electronic humidity indicator
(Humi-Check, Beckman Instruments). A hot wire anemometer (Alnor, Thermo-
aneomometer) was used to measure the velocity profile of the air over the
product in the cooler, and a vane anemometer was used to measure the average
air velocity.
Pilot Plant Operating Procedures and Production Line Measurements
Tests on the pilot plant with the cooler in the up-flow mode were con-
ducted with snap bean and lima beans during the fall of 1975. During the
summer and fall of 1976, snap beans, lima beans, broccoli, brussels sprouts
and cauliflower were tested with the cooler in the down-flow mode.
Raw vegetables for testing the pilot plant were collected into bins
1.2 m x 1.2 m x 1.2 m (4 ft x 4 ft x 4 ft) from the production line at the
stage where they were ready for blanching. The snap beans were collected
at the point in the production line after they had been washed, sorted and
cut. Lima beans were collected after they had been washed and flotation
graded in a 13 - 14% brine solution. Because the final rod-reel washers and
water-blanchers were so closely connected in the lima bean production line, it
was not possible to collect lima beans for the pilot plant runs as throughly
cleaned and washed as they were when fed to the production line blanchers.
In some cases it was necessary to collect lima beans as they left the brine
sorter without any subsequent washing; other times they could be collected
after only a brief washing following the brine separator. Brussels sprouts
(large size), cauliflower (flowerets), and broccoli (spears) were collected
after trimming and cutting, but because of the plant arrangement, it was
not possible to collect them after washing.
The testing of the pilot plant consisted of three kinds of experimental
runs: preliminary, batch and continuous. Preliminary runs were used to
establish the feed rate, blanching and cooling times and to observe the
operating characteristics of the pilot plant for each vegetable. Batch
runs consisted of blanching and cooling approximately 907 kg (2000 Ibs) of
12
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raw vegetables and determining the yield of blanched-cooled vegetables, the
solids lost from the raw vegetables and the wasteload. In the continuous
runs, the pilot plant was operated for a longer time (2-5 hrs) than in the
batch runs; the same parameters as in the batch runs were measured, but, in
addition, samples were taken for microbiological analysis and sensory evalua-
tion. A labor strike at the plant in the late summer and early fall of the
1976 season allowed only a short time to test brussels sprouts, cauliflower
and broccoli; as a result only preliminary runs were possible with these
vegetables.
The feed rates, residence times in the heater, holder and cooler, and
the flow rates of steam and air were varied in the preliminary runs to deter-
mine suitable conditions for processing the vegetables. Velocities on the
conveyors were measured by bundling approximately 200 g of vegetables in
cheescloth and timing the bundle's passage on the conveyors. With the
steam to the heater off, preliminary runs were also used to observe the
product flow on all the vibratory conveyors. With the steam to the heater
on, the vegetables leaving the cooler were tested for peroxidase (Dietrich
and Neumann, 1968), and their temperature was measured. If the peroxidase
test was negative and the product temperature was between 27 and 32°C, no
further adjustments were made, and a series of batch and continuous runs
were begun, using the conditions established in the preliminary runs.
For the batch runs, one bin of raw vegetables was weighed and dumped
into the feeder-elevator. After the temperature in the heater reached
approximately 100°C (212°F), the vegetables were started through the pilot
plant. Samples (150 g) of raw vegetables and of vegetables leaving the
cooler were taken every fifteen minutes. The vegetables leaving the
cooler were analyzed for peroxidase several times during the run. About
every fifteen minutes a 500 g sample of product leaving the cooler was
collected into a beaker, and the bulk temperature was measured with a
dial thermometer. All the vegetables leaving the cooler were collected
from the start of the run to the time when vegetables were no longer being
discharged from the holder. The effluent was weighed, and three 500 g
samples were taken in polyethylene bottles.
For the continuous runs essentially the same procedure as used in the
batch runs was repeated, except that two to four bins (1.8 - 3.6 kkg) of
raw vegetables were processed in the pilot plant giving runs from 2 to 5.5
hours. Samples (150 g) of raw vegetables and of cooled vegetables, as well
as the temperature of cooled vegetables, were taken every hour. Every hour,
samples (50-100 g for total aerobic count and 1.5 kg for sensory evaluation
and chemical analyses) were taken of the vegetables leaving the cooler. For
quality comparison, 1.5 kg samples of"blanched and cooled vegetables from
the production line were also taken every hour during the pilot plant run.
All vegetable samples were immediately frozen in a -23°C storage room and
then later transfered to a -29°C storage room. The frozen 1.5 kg samples
were later made into single composites for the production line and for the
pilot plant. The blanched and cooled vegetables were collected into bins
and weighed. The effluent was collected and weighed. If the run produced
more than 40L of effluent, then the effluent was weighed about every hour,
and from this quantity a 9 kg composite sample was taken with the remainder
13
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being discarded. From the entire collected effluent or the composite, three
500 g samples were taken in polyethylene bottles.
A series of analyses were done on the samples of the raw vegetables,
blanched and cooled vegetables, and effluent. One sample of effluent, taken
as described above for each run, was refrigerated at 1°C and a suspended
solids (SS) analysis (EPA, 1971) was done within 24 hours; analyses of
total solids (TS) and total organic carbon (TOG) (EPA, 1971) were done on
this refrigerated sample within a week of the time of the run. Another
sample bottle of effluent was frozen, and after about one month it was given
to a water analysis laboratory (R. W. Hawksley Co., Richmond, California)
for analysis of 5 day biochemical oxygen demand (BOD). A spare sample
bottle of effluent was kept frozen for checking any results that were
questionable. All vegetable samples were taken in polyethylene bags. The
frozen 150 g samples of raw and blanched-cooled vegetables were analyzed
for total solids (AOAC, 1965) within two months of the run. The 50-100 g
samples taken for total aerobic count were kept at -29°C (for less than
one month) until they were analyzed (Sharf, 1966). The vegetable composite
samples were also stored at -29°C; within 3 months of the sample collec-
tion, part (50-100 g) of the composite was used for analysis of peroxidase,
ascorbic acid and chlorophyll conversion (Dietrich and Neumann, 1968) while
the remainder was used for sensory evaluation by the Duo-Trio test (ASTM,
1968).
The only effluent and operating condition measurements made on the
production line were done on lima bean blanchers and coolers. The blanchers
in the lima bean production line were water blanchers of the reel conveyor
type. Cooling was done by either a combination of air and flume or only
flume. Three sets of measurements were made during a seven hour operating
period.. The feed rate of vegetables and the effluent discharge rate were
measured by collecting and weighing all vegetables going into the blancher
and all the effluent leaving the blancher and cooler for short intervals
(0.25 or 0.5 min). Samples of raw vegetables (150 g), blanched-cooled vege-
tables (150 g), and blancher and cooler effluents (500 g) were taken during
each measurement. The effluent samples were analyzed for TS, SS, TOC and
BOD, and the lima beans samples were analyzed for TS.
Steam flow to a steam blancher on the broccoli production line was
measured during each work shift for one week with an orfice meter and a
differential pressure recorder (Taylor Instrument Co.). The product flow
was determined from the production records for each shift, and an average
steam consumption was calculated.
Pilot Plant Operating Conditions
Tables 1, 2 and 3 are lists of the length and type of run, feed rate,
blanching time (heating and holding), holder temperatures, steam flow rate
and steam consumption, cooling time, cooled vegetable temperature, and the
wet-bulb temperature of the cooling air for the different vegetables inves-
tigated. The setting of the adjustments on the vibratory conveyors and the
14
-------
TABLE 1. OPERATING CONDITIONS FOR SNAP BEANS
Run
No.+
SB-IP
SB-2B
SB-3B
SB-4P
SB-5P
SB-6B
SB-7P
SB-8P
SB-9P
SB-10P
SB-HP
SB-12P
SB-13P
SB-14B
SB-15B
SB-16P
SB-17B
SB-18P
SB-19B
SB -2 OB
Veget. Run
Variety Time
(Min)
Galagreen
1 in cut 45
50
49
40
52
" 95
46
33
27
25
" 26
25
26
Apennine
1 in cut 60
Galagreen
1 in cut 67
Italian
Ramones 31
1 in cut
45
25
" 44
40
Feed
Rate
(kg/hr)
1000
980
960
1300
1100
1200
1200
1600
2100
2100
2100
2100
2000
1600
1600
1500
1000
1100
1100
1100
Heating
Time
(Min)
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.75
0.75
1.3
1.3
1.3
1.3
1.3
1.3
1.2
1.2
1.2
1.2
1.2
Holding Holder
Time Temp
(Min) (°C)
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
1.1
0.9
0.9
0.9
0.9
0.9
0.9
0.6
0.6
0.6
0.6
0.6
63-84
85+3
85+6
85+6
88
71-85
88+2
84+4
82+3
86+1
86+1
85+3
82+3
77+6
86+2
85+3
91+3
91+3
85+3
82+3
Steam
Flow
(kg/hr)
170
129
129
150
177
161-181
210
210-269
269
289-309
309
309
269-309
249-309
249
218
170
170
170
170
Cooled
Veget.
Temp.
30
32
31
38
29+3
29+2
30
33+3
35
36
38
36
34
31+1
37+1
37
28+1
33
26
28
Cooling
Time
(Min)
3.0
3.0
2.5
2.5
2.5
2.5
2.5
1.9
2.6
2.6
2.6
2.6
2.2
2.2
2.2
2.2
2.2
Wet-
bulb
Temp
19
18
19
18
16
13
21
19
18
23
18
17
17
17
18
17
16
Steam
Consumption
(kg/kkg)
170
130
140
110
160
140-160
190
130-170
130
140-150
150
150
130-150
160-190
150
150
170
160
160
150
(continued)
-------
TABLE 1 (continued)
Run
No.+
SB-21B
SB-22B
SB-23B _
Veget.
Variety
Galagreen
1 in cut
Italian
Ramones
1 in cut
11
Run
Time
(Min)
57
41
41
Feed
Rate
(kg/hr)
890
1200
1200
Heating
Time
(Min)
1.2
1.2
1.2
Holding
Time
(Min)
0.9
0.6
0.6
Holder
Temp
86+3
82+3
88+3
Steam
Flow
(kg/hr)
150
170
170
Cooled
Veget .
Temp
28
31
31
Cooling
Time
(Min)
2.2
2.2
2.2
Wet-
bulb
Temp
16
18
19
Steam
Consumption
(kg/kkg)
170
140
150
Asgrow 274
SB-24C
SB-25B
SB-26P
SB-27C
SB-28C
SB-29B
SB-30C
SB -3 1C
SB-32B
SB-33B
SB-34P
SB-35C
1 in cut
it
Yellow Wax
1 in cut
Juliann
1/2 in cut
Apennine
1/2 in cut
Apennine
1 in cut
"
1 in cut
Yellow Wax
1 in cut
"
Apennine
1 in cut
it
190
60
37
161
150
53
122
125
57
51
23
125
890
920
890
900
980
840
860
840
870
850
800
840
1.1
1.1
1.1
1.1
1.1
1.0
1.0
0.5
0.7
0.7
0.7
0.6
0.9
0.9
0.9
0.9
0.9
1.0
1.1
1.1
0.75
0.75
0.75
0.7
84+3
86+1
85+3
87+3
86+4
91+3
91+6
91+3
91+3
91+3
93
91+3
150-129
150
150
150
150
150
150
150
150
150
150
150-138
29+1
29
26
28
28+1
27
26
25
26
27
29
27
2.2
2.2
2.2
2.6
2.7
2.5
2.5
2.5
2.5
2.5
2.3
2.4
19
17
14
16
17
16
14
13
14
18
18
17
170-150
160
170
170
150
180
170
180
170
180
190
180-170
(continued)
-------
TABLE 1 (continued)
Run Veget . Run
No.+ Variety Time
(Min)
Galagreen
SB-36C 1 in cut 215
SB-37C " 118
P « preliminary run
B = batch run
C = continuous run
Feed
Rate
(kg/hr)
880
860
Heating
Time
(Min)
0.6
0.6
Holding Holder
Time Temp
(Min) (°C)
0.7 88+3
0.7 89+3
Steam
Flow
(kg/hr)
137
137
Cooled
Veget.
Temp
27
28
Cooling
Time
(Min)
2.4
2.4
Avg. of
Wet-
bulb
Temp
17
17
all runs
Steam
Consumption
(kg/kkg)
160
160
160
-------
TABLE 2. OPERATING CONDITIONS FOR LIMA BEANS
oo
Run.
No.
Veget. Run Feed Heating Holding
Variety Time Rate Time Time
(Min) (kg/hr) (Min) (Min)
Holder Steam Cooled
Temp Flow Veget.
(°C) (kg/hr) Temp
(°C)
Cooling Wet- Steam
Time bulb Consumption
(Min) Temp (kg/kkg)
(°C)
Pilot Plant
LB-1 P
LB-2 P
LB-3 P
LB-4 P
LB-5 P
LB-6 P
LB-7 P
LB-8 B
LB-9 B
LB-10 C
LB-11 C
LB-1 2 C
LB-1 3 C
LB-1 4 C
LB-1 5 C
LB-1 6 B
LB-1 7 C
Kingston
it
Bridge ton
it
it
S4
Kingston
S4
Bridge ton
it
Kingston
ii
Bridgeton
ii
Kingston
ii
S4
45
Run
35
Run
ii
78
83
50
57
Run
126
149
272
331
274
42
130
1300
stopped
560
stopped
ii
540
1200
1200
1100
stopped
880
840
840
700
740
970
830
1.1
because
1.1
because
n
1.1
1.1
1.1
1.1
because
1.1
1.1
1.1
1.1
1.1
0.8
0.8
1.
cooler
3.
cooler
n
1.
1.
1.
1.
cooler
1.
2.
2.
2.
2.
1.
1.
3
was
5
was
3
3
3
3
was
3
5
5
5
5
9
9
86+2
unable
98
unable
n
98
91+6
unable
91+6
92+3
93+3
93+2
91+2
98
93
129
to move
89
to move
n
89
102
129
149
to move
110
110
110
107
109
149
127
32
beans
24
beans
24+1
23
27
25
beans
29+1
28+1
28+1
26+2
28+2
26
24
17
17
13
12
14
14
16
16
16
10
1.2 10
1.7 14
1.7 13
Avg. of all runs
100
160
160
90
110
130
130
130
130
150
150
150
150
130
(continued)
-------
TABLE 2. (continued)
VD
Run . Veget. Run Feed
No. Variety Time Rate
(Min) (kg/hr)
LB PL-1 Kingston ~ 4200
LB PL -2 Kingston 3000
LB PL-3 Kingston 5600
P = preliminary run
B = batch run
C = continuous run
PL = measurements made on plant
Heating
Time
(Min)
4.5*
4.5*
4.5*
: product
Holding Holder
Time Temp
(Min) (°C)
Production Line
ion line
Steam Cooled
Flow Veget.
(kg/hr) Temp.
(°C)
31
43
39
Cooling Wet-
Time bulb
(Min) Temp
(°C)
0.9**
0.3***
0.9**
Steam
Consumption
(kg/kkg)
*blancher temperature = 99°C
**0.7 min in air with water sprays and 0.2 min in flume
***0.3 min in flume
-------
TABLE 3. OPERATING CONDITIONS FOR BRUSSELS SPROUTS, CAULIFLOWER AND BROCCOLI
to
o
Run
No.
BS-1 P
BS-2 P
BS-3 P
BS-4 P
BS-5 P
Veget.
Variety
large
size
ii
ii
"
it
Run
Time
(Min)
55
60
131
93
Feed
Rate
(kg/hr)
190
200
240
200
680
Heating
Time
(Min)
1.8
1.8
1.8
1.8
Holding
Time
(Min)
Brussels
2.4
2.4
2.4
2.4
Holder
Temp
(°C)
Sprouts
99
98+1
100
100
Run stopped because holder
Steam
Flow
(kg/hr)
149
129
129-90
90
Cooled
Veget.
Temp
35
35
40+3
32
Cooling
Time
(Min)
3
3
5
Wet-
bulb
Temp
13
13
10
13
Steam
Consumption
(kg/kkg)
780
630
540-370
430
overloaded
Cauliflower
C-l P
flowerets
53
830
1.3
0.6
99
149
21
5
180
Broccoli
B-l P
B-2 P
spears
27
40
96
240
1.4
1.2
1.3
0.8
__
99
90
90
19
5
9
900
370
preliminary run
-------
air flow rate for each run are shown in the Appendix (Tables A-l, A-2 and
A-3). Table 2 also shows the conditions on the lima bean production line
at the time of measuring the effluent.
Blanching times (heating plus holding) for each of the vegetables in
the initial preliminary runs were set on the basis of the times used on the
production line. The division of blanching times into heating and holding
times was usually made on the basis of earlier work (Bomben, et al., 1974;
Brown, et al., 1974; Lund, 1974). In the case of snap beans, a reduction to
the minimum blanching time necessary for adequate blanching in the prototype
was measured (Runs SB-35 to 37). Commercial practice in blanching lima
beans is usually to blanch beyond the point of enzyme inactivation to
attain a softer texture. Commercial blanching times for lima beans may vary
between 3.5 to 6.0 minutes; the maximum blanching time possible for lima
beans in the prototype was 3.6 minutes. The blanching times achieved with
brussels sprouts, cauliflower, and broccoli had to be set less than commer-
cial practice for reasons discussed later in this report.
The heater was maintained at the atmospheric condensing temperature of
steam (100°C) by regulating the flow of steam to the heater. The holder
temperature was measured by a thermocouple placed at 2/3 of the length of
the holder about 4 cm from the bottom. At a given heating and holding time
the steam flow was kept at a minumum while maintaining a temperature of 85
to 88°C (185 to 190°F) in the holder.
The vibration amplitude of the cooler was set at the maximum that would
give a cooled product temperature of 27 to 32°C (80 to 90°F). The equipment
setting to give this condition was established during the preliminary runs.
Some difficulty in controlling the residence time was experienced with the
up-flow cooler, and this will be discussed later in the report.
21
-------
SECTION 5
RESULTS AND DISCUSSION
The wasteload produced by the pilot plant as compared to other blanching
and cooling techniques was the focus of the project. Effluent was described
in terms of hydraulic wasteload and organic wasteload. Hydraulic wasteload
is the volume of effluent per unit of raw vegetable (L/kkg), and the organic
wasteload is the weight of the BOD, TOG and SS per unit of vegetable pro-
cessed all expressed as kg per 1000 kg of raw vegetables that had been
washed, sized, cut and trimmed. In addition to these conventional parameters
for describing the wasteload, a material balance on the vegetables passing
through the process was performed; the yield described the weight of blanched
and cooled vegetable obtained from a given weight of raw vegetable, and the
solids loss described the fraction of solids in the raw vegetable lost during
blanching and cooling. The Appendix (Table A-4) summarizes the calculations
used to obtain the wasteloads and material balances.
Most of the experience gained in operating the pilot plant was obtained
with snap beans and lima beans. Because of the limited time available for
running brussels sprouts, cauliflower and broccoli, only preliminary runs
were possible with these vegetables. During the 1975 season, the cooler
operated with product flowing up, and during the 1976 season it operated
with product flowing down.
Time limitations in this study precluded a thorough measurement of the
effluent produced by the production line. The only effluent data measured
on the production line was for lima beans. Although an attempt was made
to make measurements on the lima bean production line during normal opera-
ting conditions, the fact that the three measurements listed were all taken
during one day of plant operation limits their range of applicability.
Reliable measurements of the effluent from a blancher or flume in an
operating plant requires taking data over a period of time long enough to
encompass the range of variations that inevitably occur. Other reports
on the measurement of blancher effluent for conventional as well as new
blanching techniques (Lund, 1974; Rails and Mercer, 1974; Bomben, et al.,
1975) will be used as a basis for comparison in this report.
Product quality was another consideration in evaluating the operation
of this pilot plant. Quality was measured in three ways: (1) total aerobic
count, (2) sensory evaluation by the duo-trio test, and (3) chemical analysis
of peroxidase, ascorbic acid and chlorophyll conversion.
Economic criteria will eventually determine whether the ideas investi-
gated in this work will be commercially adopted. The economic conditions
22
-------
of an individual freezing plant are unique because of location, availability
of capital, condition of existing blanchers, and other individual economic
considerations. The economic calculations that were done for this report
simply compared fixed and variable operating costs under what was considered
reasonable operating conditions for four alternatives: vibratory spiral
blancher-cooler, conventional water blancher, hydrostatic steam blancher,
and hot-gas blancher.
Analysis of Prototype Design and Operations
An objective of the experimental runs was to observe how the vibratory
conveyors moved the vegetables in the heater, holder, and cooler. Although
vibratory conveyors are used in vegetable processing, they have rarely been
used to convey vegetables through a blancher (Commercial Mfg. Co., 1975), and
this work was the first to use spiral vibratory conveyors for this purpose.
Previous work (Brown, et al., 1974) showed that circular vibratory conveyors
gave flows approximating plug flow of the vegetables, thereby insuring uni-
form residence time for the vegetables in a blancher. The spiral conveyors
used in the pilot plant gave uniform conveying also as long as their
conveying surface was covered with vegetables. Because the blanching was
separated into heating and holding steps, any small nonuniformity of heating
in the heater spiral was equalized in the holder where vegetables piled up
for temperature equilibration and enzyme inactivation.
The design capacity of the pilot plant of 907 kg/hr (1 ton/hr) was
calculated assuming a bulk density of 641 kg/m (40 Ib/ft ) and a residence
time of 1 min. in the heater, 1 min. in the holder, and 2 min. in the
cooler. Since bulk densities can be as small as 400 kg/m (25 Ib/ft ) for
broccoli spears and blanching times for large brussels sprouts can be as long
as 6 minutes, the actual capacity depended on the vegetable being blanched.
In Runs SB-9 to SB-13 the pilot plant far exceeded its design capacity; snap
beans, whose bulk density is about 561 kg/m^ (35 Ib/ft^), were fed to the
blancher at over 2000 kg/hr (2.5 tons/hr). Lima beans, whose bulk density
is about 641 kg/m (40 Ib/ft ), but required blanching times longer than
the 2 minutes used for the design feed rate, also exceeded the design
capacity in some runs (LB-1, 7, 8, 9, and 16). Brussels sprouts, cauli-
flower, and broccoli, all of which have lower bulk densities and longer
blanching times than those used for designing the conveyors, had feed rates
below the design capacity. The actual capacity of the pilot plant for these
latter vegetables could not be accurately established for reasons mentioned
later in this report.
The blanching times for snap beans in the pilot plant (heating and
holding) sufficient to produce a negative peroxidase were generally less
than those on the production line. These shorter blanching times were
achieved because the pilot plant had sealed ends, thus insuring that the
heater was maintained at 100°C, and because the heating and holding sections
assured a uniform temperature among the individual pieces leaving the holder.
Steam blanchers with unsealed ends, such as the one used for steam flow
measurements on the production line, may have a considerable variation in
temperature along their length because of air entering through the feed and
23
-------
discharge ends. In addition, the belt in a conventional steam blancher is
often heavily loaded, which causes the vegetables within a blancher to
experience a different temperature treatment.
The holder was not large enough to provide adequate capacity for
brussels sprouts. At the feed rates shown in Table 3 for Runs BS-1 to BS-4,
the heater was not fully loaded giving some nonuniformity in blanching times.
In Run BS-5, when a more fully loaded heater was tried, the holder became
overloaded. The blanching time of 4.2 minutes (1.8 minutes heating + 2.4
minutes holding) was the maximum possible in the pilot plant. Although the
brussels sprouts processed in these experiments showed negative peroxidase
tests, the exact time of blanching was uncertain because of the underloaded
heater and the very slow conveying velocity in the holder (10 sec. on;
40 sec. off). To provide proper conditions for blanching brussels sprouts,
the size of the holder would need to be increased sufficiently to accomodate
a fully loaded heating spiral.
Broccoli spears tended to bridge and block the 15 on x 23 cm (6 in. x
9 in.) entrances and exits of the heating and cooling spirals if the feed
rate was above 240 kg/hr. Thus again the heater spiral could not be loaded
at its full capacity. For unobstructed flow of broccoli through the proto-
type, these entrances and exits would have to be enlarged. The blanching time
of 3.5 minutes used on the broccoli production line could not be achieved in
the prototype because the holder could not convey broccoli at the heavy
loading required to attain a long residence time in the holder. At the low
vibration amplitude (0.32 cm) and the long time off (40 sec.) the heavily
loaded holder conveyor could not move the broccoli. At higher vibration
amplitudes (0.64 cm or larger) or lighter loadings (on continuously) the
broccoli could be moved by the conveyor, but of course these conditions
gave a shorter holding time. Adequate holding time with broccoli would be
possible with a longer holder.
Cauliflower moved uniformly and without difficulty through all conveyors
in the pilot plant. However, to use the spiral conveyors at full capacity
and to provide for a longer holding time (conventional blanching times =3.5
min.), a larger holder would be necessary.
Because of the equipment limitations mentioned above, the capacity of
the pilot plant for brussels sprouts, cauliflower and broccoli could not
be determined in these tests. The tests did establish that the vibratory
conveyors could move these vegetables and that adequate blanching and cooling
could be achieved in the prototype; however, establishing the exact sizes of
the holder and feed and discharge openings needed so that the prototype could
handle these vegetables continuously and reliably would require further
testing.
Table 1 shows that in those runs with snap beans where the feed rate
exceeded the design capacity, the cooled vegetable temperatures exceeded
27°C (80°F), which was the design product temperature. In the snap bean and
lima bean runs done at the design capacity, the cooled product temperature
was generally at or below 27°C. The actual temperature in any given run
was dependent on the wet-bulb temperature of the ambient air. The low
24
-------
temperatures achieved with cauliflower and broccoli were the result of the low
conveyor loadings and the very low wet-bulb temperatures of the ambient air.
Figure 6 shows the results of measurements of air velocities as a function
of distance above a conveyor flight. It clearly shows that most of the air
was not being aimed at the product. This condition gave adequate cooling
when the pilot plant was operated at its design capacity since only a single
layer of product was on the cooler conveyor; whereas at the higher feed rates
tried in Runs SB-9 to SB-13, the cooler conveyor had multiple layers of
product. An air distribution system, which aimed the air directly at the
product, would give more air flow over the product and thereby increase the
rate of cooling and give a higher cooler capacity. Air could be directed
at the product by using slotted tubes extending from the existing air holes
out to the edge of the flights.
The cooler was operated with product flowing upward during the 1975
season and downward during the 1976 season. The cooler operated satisfac-
torily with snap beans in either mode of operation (Runs SB-1 to SB-3 were
up-flow), but it had more capacity in down-flow operation. The cooler could
move lima beans upward, but the flow was erratic, and sometimes the lima
beans could not be moved at all by the conveyor. This problem was intermit-
tent, and no single cause for its occurence was determined although the
following characteristics were observed: (1) The longer the lima beans were
blanched, the more slowly they tended to move on the conveyor. (2) Stems,
pods, and undersize beans collected on the surface of the cooler conveyor.
(3) If during a run the lima beans stopped moving in the cooler and then
the cooler was washed down with water, the cooler could again convey the
lima beans. Despite these problems the cboler in up-flow was operated con-
tinuously with lima beans without washing for over five hours (Run LB-14).
None of these problems were encountered when cooling lima beans in the
down-flow mode (Runs LB-16 and -17).
The cooler could not continuously convey upward blanched brussels
sprouts, blanched cauliflower or blanched broccoli; it was able to convey
upward raw brussels sprouts and raw broccoli but not raw cauliflower.
Changing the angle of vibration from 45° to 30° from the horizontal did not
make these vegetables move up the cooler. The cooler had no difficulty in
conveying any of these vegetables downward. From the standpoint of design,
the only disadvantage of not being able to convey upward in the cooling
spiral is some loss in compactness since the overall height of the equipment
must be higher for down-flow (Figure 2 and 4).
The cleaning of the pilot plant was easily accomplished after every
run. The smooth stainless steel surfaces of the conveyors were easily
cleaned with cold water, and the spray system could easily be flushed with
detergent. Clean-in-place equipment would appear to be easily incorporated
in the design. Microbiological assays of vegetables leaving the cooler,
described later in this report, show that the sanitation of the design is
well within accepted limits.
25
-------
FROM BOTTOM
FROM BOTTOM
BOTTOM
OF
NEXT
FLIGHT
I I
. CENTER OF AIR
I ^DISTRIBUTING HOLE
5 10 15 20 25 30 35 40
DISTANCE ABOVE COOLER CONVEYOR SURFACE (cm)
Figure 6. Air velocity distribution over cooler spiral conveyor.
26
-------
Material Balances and Wasteload
Tables 4, 5, and 6 show the characteristics of the liquid effluent from
the pilot plant and the results of a material balance on the different vege-
tables entering and leaving the pilot plant for each of the runs. In the
case of lima beans, the three measurements made on the production line are
also shown in Table 5. The Appendix (Tables 5, 6 and 7) gives the
results of the wastewater analyses for each of the runs. A total volume of
effluent of less than 0.5 liter collected during a run was considered negli-
gible, and this small amount of effluent is indicated by hydraulic loads
preceeded by a "less than" sign (<). Table 7 shows the means of the values
in Table 4, 5, and 6 grouped by vegetable variety. When there were a suffi-
cient number of runs to make it applicable, a 95% confidence limit was
calculated.
The variations in hydraulic wasteload and organic wasteload for a given
vegetable appeared to be primarily because of variations in the raw vegetable
variety and maturity. Table 7 indicates that for snap beans the variety made
a significant difference in the wasteload. Within a given variety of snap
beans (Tables 1, 4 & 7) the variations in wasteload are not large with the
exception of Run SB-12, which was a short duration preliminary run. On the
other hand, lima beans showed no distinguishable correlation between variety
and wasteload. Lima beans did however have large variations in wasteload
among runs of a given variety (Tables 2, 5 and 7). Comparisons between Runs
LB-15 (36.09% total solids, Kingston variety) and LB-16 (38.70% total solids,
Kingston variety) and LB-13 (41.6% total solids, Bridgeton variety) and
LB-14 (35.92% total solids, Bridgeton variety) indicated that lima beans with
higher solids content produced less wasteload. One would expect that a lower
volume of effluent would be produced during the blanching of a drier or more
mature (higher solids content) raw vegetable [Lund (1974) and Bomben, et al.
(1973)]. There were not enough runs done with brussels sprouts, cauliflower
or broccoli to make observations about variations in wasteload.
The material balances calculated in Tables 4, 5, 6 and 7 were done to
trace the loss of solids and weight during blanching and cooling. Bomben,
et al. (1975) demonstrated that different methods of cooling led to differ-
ences in yield and solids loss. The yield is important in vegetable freezing
since frozen vegetables are sold by weight. Air cooling obviously reduces
the hydraulic load as compared to flume cooling, but at the expense of a
lower vegetable yield. Yields of greater than 100% are possible since the
vegetables can absorb more liquid in cooling than was lost in blanching.
Solids loss is a measure of the nutrients that are leached from a vegetable
as it is blanched and cooled. Measurements on the production line were
made only for lima beans, but it was not possible to measure accurately the
yield, so that solids loss is the only material balance comparison possible
between commercial processing and the pilot plant. Table 7 clearly shows
for lima beans the advantages in solids retention and wasteload reduction
possible with the pilot plant as compared to the production line.
27
-------
TABLE 4. YIELD, SOLIDS LOSS & LIQUID WASTELOAD FOR SNAP BEANS
Run No.
SB-1 P
SB-2 P
SB-3 P
SB-4 P
SB-5 P
SB-6 B
SB-7 P
SB-8 P
SB-9 P
SB-10 P
SB-11 P
SB-1 2 P
SB-1 3 P
SB-1 4 B
SB-1 5 B
SB-1 6 P
SB-1 7 B
SB-1 8 P
SB-1 9 B
SB-20 B
SB-21 B
SB-22 B
SB-23 B
SB-2 4 C
SB-2 5 B
SB-2 6 P
SB -2 7 C
SB-2 8 C
SB-2 9 B
SB -30 C
SB-31 C
SB-3 2 B
SB-33 B
SB-34 P
SB -3 5 C
SB -3 6 C
SB-3 7 C
Yield
(%)
86.5
98.5
97.2
96.7
99.4
96.4
99.7
98.7
98.5
95.6
100
96.3
96.0
102
98.7
98.5
102
99.5
99.1
99.1
96.8
96.1
101.6
98.8
95.1
99.8
96.4
95.8
95.5
98.2
95.8
94.1
94.9
90.6
98.6
99.4
98.8
Solids
Loss
(%)
MTO
0.71
0.68
0.62
0.18
0.76
1.1
0.50
2.2
0.21
1.2
1.0
1.4
1.9
0.85
0.29
0.94
1.6
1*4
1.3
1.8
1.7
1.7
1.6
1.4
0.41
0.89
Hydraulic
Load
(L/kkg)
51
32
29
33
5.7
8.5
23
38
15
79
<0.6
7.6
<0.3
35
43
<0.6
<0.6
<0.6
<0.6
34
<0.6
<0.6
47
27
13
23
41
39
34
53
58
61
60
51
13
27
BOD
(kg/kkg)
0.80
0.52
0.44
0.89
0.59
0.90
0.85
0.98
--
1.2
0.34
0.57
TOC
(kg/kkg)
0.62
0.31
0.29
0.28
0.06
0.29
0.43
0.22
0.95
0.11
0.42
0.46
0.49
0.63
0.29
0.13
0.36
0.52
0.49
0.50
0.59
0.52
0.50
0.56
0.18
0.37
SS
(kg/kkg)
TT,M
0.037
0.044
0.043
0.14
0.16
0.15
0.20
0.090
0.041
0.11
0.14
0.13
0.14
0.20
0.15
0.16
0.15
0.057
0.12
28
-------
TABLE 5. YIELD, SOLIDS LOSS & LIQUID WASTELOAD FOR LIMA BEANS
Run No. Yield Solids
Loss
/<» N f
-------
TABLE 6. YIELD, SOLIDS LOSS AND LIQUID WASTELOAD FOR BRUSSELS SPROUTS,
CAULIFLOWER AND BROCCOLI
Run No. Yield
f a/ \
\ *9 s
Solids
Loss
( **/ \
\/o /
Hydraulic
Load
(L/kkg)
BOD
(kg/kkg)
TOG
(kg/kkg)
SS
(kg/kkg)
BS-1 P
BS-2 P
BS-3 P
BS-4 P
BS-5 P
C-l P
B-l P
B-2 P
102
88.7 0.29
94.4 0.65
Run stopped
97.2
103
0.33
Brussels Sprouts
<3
<3
15
41
0.27
0.59
0.15
0.31
0.052
0.093
Cauliflower
<3
Broccoli
11
0.25
0.15
0.091
Product Quality
Table 8 shows the results of the total aerobic counts done on vegetables
leaving the cooler. The counts on all the lima bean samples taken from the
pilot plant were much lower than those of product taken from the production
line, and these counts were far below the acceptable 10 colonies/g indicated
by'Sharf (1966). In most of the runs with snap beans the counts on the
cooled vegetables from the pilot plant were much higher than the production
line (Run No. SB-24 to -36). These runs were all done with the product
flowing downward in the cooler, and an inclined belt had to be used to
elevate the cooled vegetables from the exit of the cooler to a collection
bin (Figure 5). In runs SB-24 to -36, samples were taken from the vegetables
leaving the inclined belt elevator; however in Run SB-37, samples were taken
directly from the exit of the spiral cooler, and the counts obtained on those
samples were much lower than those of previous runs and about the same as
the production line. Runs LB-11 to LB-15 were done with product flowing
upward in the cooler, and thus did not require an inclined-belt elevator.
Samples for LB-17, BS-3, BS-4 and C-l were also taken directly from the exit
of the down flow cooler. The high counts when using the inclined belt eleva-
tor dramatically point out the difficulty in keeping belt conveyors clean
as opposed to vibratory spiral conveyors. In all cases where vegetables
were taken directly from the spiral conveyors, the counts were lower than,
or about the same as, the counts of vegetables taken from the production
line; furthermore, the counts on the vegetables from the pilot plant showed
, 30
-------
TABLE 7. MEANS OF YIELDS, SOLIDS LOSSES AND LIQUID WASTELOADS WITH 95%
CONFIDENCE LIMITS
Snap Beans
Galagreen
Apennine
Ramones
Lima Beans
Kingston
Bridge ton
S-4
Production Line
blanching-
cooling-
blanching + cooling
Brussels Sprouts
Cauliflower
Yield
97.2+0.4
96.6+1.2
99.4+0.7
90.5+2.3
89.4+7.7
91.3+1.0
*
95.0+9.6
97.2
Broccoli 103
Solids
Loss
0.83+0.09
1.51+0.07
not enough
0.50+0.18
0.37+0.53
0.052
1.64+0.06
0.73+0.58
2.37
0.47
»«
0.33
Hydraulic
Load
(L/kkg)
27.0+2.6
39.8+6.8
effluent for
27.9+9.6
24 + 15
18 + 27
460 + 130
540 + 340
1000
15 + 14
3
11
BOD
(kg/kkg)
0.53+0.10
0.98+0.12
sample
0.90+0.61
0.56+0.42
0.44
3.37+0.49
0.98+0.09
4.35
0.43
__
0.25
TOG
(kg/kkg)
0.36+0.03
0.53+0.02
0.55+0.23
0.47+0.32
0.30
1.74+0.07
0.41+0.04
2.15
0.23
__
0.15
ss
(kg/kkg)
0.084+0.017
0.15 +0.02
0.54 +0.28
0.16+ 0.07
0.23
0.79+0.14
0.14+0.02
0.93
0.073
0.091
*Yield could not be accurately measured on the production line.
-------
TABLE 8. TOTAL AEROBIC PLATE COUNTS ON VEGETABLES LEAVING COOLER
1
Snap Beans
SB-24 7.9 x 104
SB-27 6.4 x 10;?
SB-28 1.5 x 10^
SB-30 9.2 x 104
SB-31 1.9 x 10^
SB-35 4.8 x 10;?
SB-36 9.2 x 10;?
SB-37 1.2 x 103
Lima Beans
LB-11 2.0 x 103
LB-12 7.0 x 102
LB-13 1.2 x 103
LB-14 5.1 x 10*
LB-15 7.3 x 10*
LB-17 3.8 x 104
Brussels Sprouts
BS-3 1.4 x 104
BS-4 3.8 x 105
Cauliflower
C-l 4.9 x 104
(Colonies/g)
Hours After Start of Run
234
3.5 x 104 3.2 x 104
9.8 x 104 1.3 x 10;?
1.4 x 10;? 1.0 x 105
1.0 x 10;?
1.6 x 10;?
4.3 x 10;?
2.9 x 10^ 2.2 x 105 6.0 x 105
6.1 x 102
1.5 x 103
7.5 x 102 4.6 x 102
8.3 x 102 5.8 x 102
7.0 x 102 1.3 x 103 2.0 x 103
5.0 x 102 5.0 x 102 5.0 x 102
4.3 x 104
2.0 x 103
1.7 x 105
Production
5 Line
30
__
20
1.0 x 102
6.2 x 103
3.7 x lO2
2.1 x lO2
7.0 x 102
7.2 x 104
1.1 x 103
1.5 x 106
1.4 x 10^
1.1 x 105
32
-------
no tendency to increase with time, as demonstrated by Run LB-14, which
continued for over five hours.
Table 9 gives the results of sensory comparisons (duo-trio) of product
from the pilot plant with that from the production line. The results are
reported as the number of judgements correctly identifying the sample that
was identical to the control (% correct). The control for a comparison was
either the pilot plant or production line sample. Judges were also asked
to state which sample they preferred. Probabilities are from the Binomial
Probability Table.
TABLE 9. SENSORY EVALUATION OF SNAP BEANS AND LIMA BEANS BY DUO-TRIO TEST
Run
Number
Total Number
of Judgments
% Correct
% Preference
for Pilot Plant
Sample
SB-1 36
SB-2 36
SB-3 34
SB-28 40
SB-36 40
SNAP BEANS
61
61
53
68*
78**
42
44
68
65*
58
LIMA BEANS
LB-7 41
LB-8 40
LB-9 41
LB-10 38
LB-11 40
*Probability < 0.05
**Probability < 0.01
66*
65*
80**
63
63
54
67*
63
32*
55
The sensory evaluation showed that in some cases a significant differ-
ence could be detected in the taste or texture of the product because of
processing in the pilot plant as compared to processing in the production
line. In those cases of snap beans where significant differences could be
detected, the judges, citing better flavor or texture, preferred the sample
from the pilot plant. This better flavor or texture could have been either
the result of the shorter blanching times or less loss of solids in the pilot
plant as compared to the production line. In the case of lima beans, the
preferences of the panel were not as consistent, and in one case (LB-10)
the panel preferred lima beans taken from the production line. Some of the
differences found by the judges in the lima bean samples probably came from
33
-------
the fact that the lima beans for the pilot plant could not be collected
after the final wash prior to blanching, and thus contained more of the
salt absorbed in the flotation grader. In general it appears safe to con-
clude that the pilot plant had no adverse affect on the taste, texture or
appearance of vegetables, and in some cases, it improved the flavor and
texture.
Table 10 gives the results of the analyses for total solids, peroxidase,
ascorbic acid and chlorophyll conversion of pilot plant and production
line samples. The numbers are averages of two or three analyses done on
50 to 100 g of vegetables. Ascorbic acid is reported without accounting
for differences in moisture between the frozen vegetables from the production
line and those from the pilot plant.
The results of peroxidase test are reported in two ways. In those cases
where a raw vegetable sample was available at the time of analysis, a resi-
dual peroxidase was determined; otherwise the time for a color change in the
test solution is reported. For the conditions used in this test, adequate
blanching was shown by less than 6% residual peroxidase or no color change
in more than 210 sec. Except for one sample of brussels sprouts taken from
the production line (BS-3), all samples shown in Table 10 were adequately
blanched. Lima beans are commonly blanched longer than necessary for peroxi-
dase inactivation, the criterion being texture instead. Since in most cases
the pilot plant used shorter blanching times, the peroxidase contents of
vegetables that were processed in it were higher, but in no case did the
pilot plant not blanch sufficiently. In one of the runs with brussels
sprouts (BS-4), the pilot plant vegetables were seriously overblanched
because of the difficulties, described earlier, in maintaining constant
holding times with the holder operating at a very slow conveying velocity.
Generally, the ascorbic acid content of the vegetables processed in
the pilot plant was higher than that of the vegetables taken from the produc-
tion line (Table 10). Some of these differences can be accounted for by
differences in total solids between the samples, but in some cases (SB-2,
-3, -28, -36) the vegetables processed in the pilot plant did indeed have
more retention of ascorbic acid. This retention could have been the result
of both shorter blanching times and less leaching.
Ascorbic acid is lost both by leaching and thermal degradation, but an
increase In chlorophyll conversion is solely a measure of thermal degrada-
tion. As explained previously, the conveying velocity in the lima bean
runs with product flowing upward in the cooler was sometimes slow and
erratic, and the heavily loaded conveyor gave an excessively slow cooling
rate. This slower cooling rate caused higher chlorophyll conversions than
those on the production line (Table 10, runs LB-12, 13, 14, and 15). In
those lima bean runs with up-flow where the cooler had shorter residence
times and less loading (LB-8 and -11) and the down-flow run (LB-17), no
substantial differences between chlorophyll conversions in the prototype
and production line samples appeared. The prototype samples of snap beans,
in either up-flow or down-flow, had lower chlorophyll conversions than did
the production line samples, indicating that the prototype, when operating
34
-------
TABLE 10. CHEMICAL ANALYSES OF VEGETABLES
u>
Run
No.
SB-1
SB-2
SB-3
SB-2 8
SB-3 6
LB-8
LB-11
LB-12
LB-13
LB-14
LB-15
LB-17
Raw
TS
(%)
10.76
10.75
10.75
9.35
10.97
40.65
40.86
40.72
41.60
35.92
36.09
41.82
Blanch & Cool
TS
Pilot Prod.
Plant Line
(%) (%)
11
10
10
9
10
41
39
40
40
35
36
39
.20 10.35
.75
.40
.09
.23
.71 34.60
.74 36.49
.13 36.01
.71 38.03
.62 34.80
.07 34.82
.29
Pilot
Plant
Yield
(%)
86.5
98.5
97.2
99.4
99.4
92.1
93.2
92.9
92.1
92.0
90.8
Residual Ascorbic*
Pilot Peroxidase Acid
Plant Pilot Prod. Pilot Prod.
Solids Plant Line Plant Line
Loss (%) (%) (%) (mg/100 g) (mg/100 g)
__
0.708
0.707
1.56
0.412
0.052
0.202
0.372
0.148
0.794
1.22
SNAP BEANS
2.1
1.1
1.5
402sec**
300sec**
LIMA BEANS
0.0
0.0
0.0
0.0
0.0
0.0
>1500sec**
1.6
0.5
0.5
595sec**
SOOsec**
0.0
0.0
0.0
0.0
0.0
0.0
>1500sec**
14.1
15.1
14.1
11.7
14.0
18.7
26.7
27.2
20.6
19.1
24.6
23.7
13.9
13.4
13.4
9.8
11.8
16.7
23.8
24.0
19.7
20.3
25.7
7.0***
Chlorophyll
Conversion
Pilot Prod.
Plant Line
(%) (%)
16.8
13.8
13.8
18.2
11.9
13.0
11.9
17.2
15.6
19.1
18.9
13.5
16.8
14.1
14.1
_ _
14.5
13.9
10.8
13.0
11.3
8.0
55.2***
BRUSSELS SPROUTS
BS-3
BS-4
13.91
13.15
13
12
.42
.42
88.7
94.4
0.293
0.645
330sec**
lOOOsec**
HOsec**
290sec**
62.0
75.5
69.6
66.0
55.6
75.6
37.2
43.8
*Ascorbic acid analyses were not corrected for differences in the amount of water in the vegetables,
**Time for color change in peroxidose test; no color change in > 210 sec or < 6% residual peroxidase
indicates adequate blanching.
***Sample may have been left at room temperature too long before freezing.
-------
properly, could rapidly blanch and cool vegetables. The high chlorophyll
conversion shown for brussels sprouts in Run BS-4 resulted from the condi-
tions of overblanching discussed earlier.
Effluent Generation and Steam Consumption of Blanchers
Table 11 compares the wastewater produced by various blanching tech-
niques. The data reported by Bomben, et al. (1975) was from small scale
tests, and included cooling. The data reported by Lund (1974) and Flails
and Mercer (1974) was taken either in pilot plants or commercial production
.line blanchers, and they do not include cooling.
The organic wasteload for snap beans and lima beans from the spiral
vibratory blancher-cooler was essentially the same as that found by Bomben,
et al. (1975) in their small scale tests of conventional steam blanching
and air cooling with condensate spray. The hydraulic load from the vibra-
tory blancher-cooler pilot plant was less than that from the small scale
tests done by Bomben, et al. (1975) probably because the pilot plant used
a larger ratio of air to vegetables and thus had more evaporation during
cooling.
The results of other work done on a pilot plant or production line
scale shown in Table 11 do not include the wasteload from cooling, and
therefore they cannot be directly compared to the results of this work.
Except for hot-gas blanching, the vibratory spiral blancher-cooler generally
produced about the same or less organic wasteload for both blanching and
cooling than did the others for blanching alone. It should also be noted
that in the case of snap beans, the work cited here (Lund, 1974; Rails and
Mercer, 1974) was blanching for canning, and thus the beans were heated to
lower temperatures; a lower product temperature probably produced less
wasteload.
Since blanching is the major source of organic wasteload in most
vegetable processing plants (Rails and Mercer, 1973), reduction or elimi-
nation of its wasteload will have a major effect on the plant effluent.
Even though it eliminates effluent completely for snap beans, hot-gas
blanching does not do this for all vegetables (Rails and Mercer, 1974).
In addition this technique is dependent on increasingly scarce natural gas
as a heat source, which will probably preclude its being used commercially.
The small hydraulic load from the vibratory spiral blancher-cooler would
significantly reduce the volume of plant wastewater that had to be treated.
Table 12 gives the steam use for various blanching systems. The calcu-
lations for the theoretical steam requirement and for the steam equivalence
of hot-gas blanching are shown in the Appendix (Table A-8). The vibratory
spiral blancher-cooler has the highest steam efficiency, thereby showing
the effectiveness of its seals against steam leakage and its double wall
insulation. The low efficiency of conventional steam blanchers is readily
apparent, and even with the newly designed hydrostatic steam blanchers,
the efficiency is low as compared to the vibratory spiral blancher-cooler.
Although the hot-gas blanching pilot plant has a higher efficiency than
36
-------
TABLE 11. WASTELOAD PRODUCED BY DIFFERENT BLANCHING TECHNIQUES
Blanching Technique
Hydraulic
Load
(L/kkg)
BOD
(kg/kkg)
Organic Load
TOC
(kg/kkg)
SS
(kg/kkg)
Vibratory Spiral Blancher-Cooler*
Snap beans (Galagreen) 27
Lima beans (Kingston) 28
Water Blanching with
Air/Water Spray Cooling*
Lima beans (Kingston) 1000
Steam Blanching and
Air Cooling with Cond. Spray+
Snap beans (Galagreen) 50
Lima beans (Kingston) 40
Steam Blanching
and Water Cooling
Snap beans (Galagreen) 5100
Lima beans (Kingston) 5100
Steam Blanching
without Cooling**
Snap beans 120
Lima beans 240
Water Blanching
without Cooling
Snap beans"1"1" 600
Snap beans** 340
Lima beans** 820
Hot-Gas Blanch-
ing without Cooling"*"*"
Snap beans 0.06
*This work
Bomben, et al. (1975)
**Lund (1974)
"""Rails and Mercer (1974)
0.53
0.90
0.55
3.5
3.2
0.65
< 0.01
0.36
0.55
2.15
0.37
0.60
1.5
2.8
0.084
0.54
0.93
0.02
0.61
< 0.01
37
-------
TABLE 12. ENERGY USE IN BLANCHING
Steam
Blanching Technique Requirement Efficiency
(kg/kkg) (%)
Theoretical* 134 100
Vibratory Blancher-Cooler** 158 85
Conventional Steam**
Blancher 2580 5
Hydrostatic Steam+
Blancher 500 27
Hot-Gas Blanching* 240 56
(steam equivalent)
Conventional Water Blancher"*"*" 60
*See Appendix, Table A-8
**This work
Ray (1975) and Layhee (1975)
Estimated using information given by Lazar and Rasmussen (1964)
commercial steam blanchers, its efficiency is substantially lower than that
of the vibratory spiral blancher-cooler. No measurement of the steam con-
sumption of the water blanchers in the production line was made, nor was
it possible to find any steam consumption measurements for water blanchers
reported in the literature. The efficiency reported in Table 12 for water
blanchers was estimated from remarks made by Lazar and Rasmussen (1964).
Generally, it appears reasonable that the efficiency of water blanchers
would be higher than that of conventional steam blanchers since water
blanchers have less surface area for heat loss and they do not discharge
as much steam to the surroundings at the feed and discharge.
Cost Estimates
Table 13 shows the capital cost of four blanchers. Since conventional
steam blanchers are usually custom-fabricated, accurate purchase costs could
not be obtained; therefore, it was decided not to include this type of
blancher in the cost analysis. The hydrostatic steam blancher can be viewed
as an improved version of a conventional steam blancher, and except for steam
efficiency, its cost is probably similar to that of conventional steam
blanchers. Except for the hot-gas blancher, equipment purchase costs were
based on equipment manufactures' price quotations for a capacity of A.5 kkg/
hr (5 tons/hr) of snap beans (2.0 minute blanching time). The purchase cost
38
-------
TABLE 13. CAPITAL INVESTMENT FOR BLANCHERS AND COOLERS
Item"1
Vibratory
Spiral
Blancher-
Cooler
Water
Blancher
Hydrostatic
Steam
Blancher
Hot-Gas
Blancher
1. Equipment purchase
Cost
2. Delivery
3. Installation
4. Floor space
5. Indirect costs
$108,000
$174,000
$16,000
$28,000
$ 87,000
$147,000
$127,000
5,000
22,000
4,000
35,000
1,000
3,000
2,000
6,000
4,000
17,000
9,000
30,000
6,000
25,000
25,000
46,000
$229,000
1. Equipment purchase costs were obtained from equipment manufactures,
except for the Hot-Gas Blancher whose cost was taken from Rails and
Mercer (1974) and corrected to 1976 prices by the Marshall and
Stevens Eqiupment Cost Index (Peters and Timmerhause, 1968). The
water blancher and hot-gas blancher included an estimate of $5,000
for a cooling flume.
2. 5% of the equipment purchase cost.
3. 20% of the equipment purchase cost.
2
4. Floor space was vlalued at $270/m . Floor space requirements are
estimated as follows:
Vibratory Spiral Blancher-Cooler 15m
Water blancher 6nr
Hydrostatic Steam Blancher 33nT
Hot-Gas Blancher
931^
5. 25% of the total of items 1 to 4.
39
-------
of the hot-gas blancher was based on the costs reported by Rails and Mercer
(1974). Other items in estimating direct fixed capital were taken as per-
centages of equipment purchase cost (Peters and Timmerhaus, 1968). Floor
space was valued at $270/m ($25/ft ). The purchase costs of the water
blancher (reel type) and hot-gas blancher included $5,000 for a flume
cooler. The vibratory spiral blancher-cooler and the hydrostatic steam
blancher have the cooler as an integral part of the blancher.
. Table 14 shows the labor, capital related, and utility and waste treat-
ment costs for the four blanchers, as well as the basis used for calculating
these costs. Since the open mesh conveyor belts used in the hydrostatic and
hot-gas blanchers probably require more maintenance than the conveying sys-
tems used in the vibratory spiral or water blancher, higher maintenance costs
were used for the former. There were no data available for the wasteload of
hydrostatic steam blanchers; therefore, their wastewater costs was calculated
from the wasteload of conventional steam blanching with flume cooling (Table
11). The water use and wasteload for flume cooling were added to those of
water blanching and hot-gas blanching to get an overall cost of water and
wastewater for these sytesms.
The low capital investment needed for a water blancher is the reason
for its lowest cost of operation. The lower costs of steam, water and
wastewater treatment for the vibratory spiral blancher-cooler as compared
to the water blancher and flume were insufficient to compensate for the
lower costs associated with capital investment. A doubling in the combined
cost of utilities and wastewater treatment would give the vibratory spiral
blancher-cooler an operating cost equivalent to that of the water blancher
and flume. The hot-gas blancher's high cost is attributable mostly to high
capital related costs, while that of the hydrostatic steam blancher is
because of capital related and steam costs.
No attempt was made in these calculations to account for the loss of
vegetable weight when air cooling is used. If frozen vegetables' are valued
at $440/kkg ($0.20/lb), a 2% loss of yield resulting from air cooling as
compared to flume cooling (Bomben, et al., 1975) would add the equivalent
of $8.80/kkg to the cost of blanching and cooling since frozen vegetables
are marketed by weight. Such a large penalty for air cooling cannot be
economically justified. A standard other than weight for marketing frozen
vegetables (e.g. number of vegetables per package or total solids per
package) would be required to take full advantage of the wastewater reduc-
tion possible with air cooling. One should also note that at a price of
$440/kkg for frozen vegetables, the entire cost of blanching and cooling
is less than 2% of the cost of production. The small impact of blanching
and cooling on the total cost of production gives the processor little
economic incentive for capital investment in new blanchers or coolers.
Table 15 gives a comparison of the cost of the vibratory spiral blancher
(without cooler) and the water blancher (without flume) as they would be used
for canning vegetables. All other conditions of the cost calculation remain
the same. The water blancher still gives the lower cost of operation, and
here again a doubling in the combined cost of fuel, water and wastewater
treatment would make the cost of operating the vibratory spiral blancher
40
-------
TABLE 14. COST OF BLANCHING AND COOLING FOR FREEZING ($/kkg)*
Vibratory Spiral Water Hydrostatic Hot-Gas
Item Blancher-Cooler Blancher Steam Blancher Blancher
Labor Costs
1.
2.
3.
4.
5.
6.
7.
8.
9.
Operating labor
Supervision,
fringe benefits,
laboratory, etc.
Maintenance
Depreciation
Insurance , taxes ,
other expenses
Steam
Electricity
Water
Waste water
Total Cost
0.63
0.41
1.04
0.69
1.37
1.10
3.16
1.24
0.05
0.00
0.01
1.30
5.50
0.63
0.41
1.04
Capital
0.11
0.22
0.18
0.51
Utilities and
1.75
0.01
0.66
0.15
2.57
4.12
0.63
0.41
1.04
Related Costs
1.17
1.17
0.94
3.28
Waste Treatment
3.91
0.03
0.64
0.14
4.72
9.04
0.63
0.41
1.04
1.82
1.82
1.46
5.10
Costs
1.40
0.46
0.64
0.12
2.62
8.76
*Annual production - 4.5 kkg/hr x 14 hrs/day x 200 days/yr = 12,600 kkg/yr
+1. 1/4 man/shift for operation and 1/4 man/shift for cleaning (2 shifts/day)
with average hourly wage = $5/hr: 2(2 +2) $5/(14 x 4.5) = $0.63/kkg =
$0.57/ton.
2. Supervision, fringe benefits, laboratory, supplies, etc. = 65% of opera-
ting labor.
3. Maintenance = 5% of direct fixed capital/yr for vibratory spiral and
water blanchers and 10% of direct fixed capital for hydrostatic steam
and hot-gas blanchers.
4. Depreciation - 10% of direct fixed capital/yr.
5. Insurance, taxes and other fixed expenses = 8°
yr.
of direct fixed capital/
6. Steam - $7.83 kkg of steam ($3.55/1,000 Ib steam). Steam cost for
Hot-Gas blancher includes cost of gas ($0.0013/MJ). (Johnnie and
Aggarwal, 1977.
(continued)
41
-------
TABLE 14 (continued)
7. Electricity = $0.00389/MJ ($0.018/kw-hr). (Johnnie and Aggarwal, 1977).
8. Water = $0.13/kL ($0.50/1,000 gal). (Johnnie and Aggarwal, 1977).
9. Wastewater = $0.018/kL ($0.062/1,000 gal), $0.022/kg BOD ($0.01/lb BOD),
$0.044/kg SS ($0.02/lb SS). These costs are averages of values reported
by Carroad (1975). Total wastewater cost is the sum of these costs for
the snap bean wasteloads shown in Table 11, with the addition of flume
cooling water (4900 1/kkg, 1.6 kg/kkg BOD) for the water and Hot-Gas
blanchers (Bomben, et al. 1975).
equal to that of the water blancher. (A doubling in costs would be equiva-
lent to a 7.2% annual increase for ten years). By removing the necessity
of cooling, the fixed capital investment of the vibratory spiral equipment
is reduced by 53%, while for the water blancher the removal of the flume
reduced the investment by only 28%.
42
-------
TABLE 15. COST OF BLANCHING WITHOUT COOLING FOR VIBRATORY SPIRAL BLANCHER
AND WATER BLANCHER
Vibratory Spiral Water
Blancher Blancher
Labor Costs ($/kkg)
1. Operating labor 0.63 0.63
2. Supervisor, fringe 0.41 0.41
benefits, etc. 1.04 1.04
Capital Related Costs ($/kkg)
3. Maintenance 0.33 0.08
4. Depreciation 0.65 0.16
5. Insurance, taxes, 0.52 0.13
etc. 1.50 0.37
Utilities and Waste Treatment Costs ($/kkg)
6. Steam 1.24 1.75
7. Electricity 0.01 0.01
8. Water 0.02
9. Wastewater 0.02* 0.02
1.27 1.80
Total Cost 3.81 3.21
Fixed Capital Investment($)
Purchase Cost 51,000 11,400
Delivery 2,500 600
Installation 10,200 2,300
Floor Space 2,000('+; 1,700
Indirect Costs 16,400 4,000
$82,100 $20,000
* Wasteload was taken as that of a conventional steam blancher.
+ 7.5m2
43
-------
REFERENCES
AOAC. 1965. Official Methods of Analysis, 10th ed. Association of Official
Agricultural Chemists, Washington, D. C. p 308.
ASTM. 1968. Manual on Sensory Testing Methods. American Society for Testing
Methods, STL No. 434.
Bomben, J. L., W. C. Dietrich, D. F. Farkas, J. S. Hudson, E. S. De Marchena,
and D. W. Sanshuck. 1973. Pilot plant evaluation of Individual Quick
Blanching (IQB) for vegetables, J. Food sci. 38:590.
Bomben, J. L., G. E. Brown, W. C. Dietrich, J. S. Hudson, and D. F. Farkas.
1974. Integrated blanching and cooling to reduce plant effluent.
Proceedings of the 5th National Symposium on Food Processing Wastes,
Monterey, CA. EPA-660/2-74-058. U.S. Environmental Protection Agency,
Corvallis, Oregon, p 120.
Bomben, J. L., W. C. Dietrich, J. S. Hudson, H. K. Hamilton, and D. F.
Farkas. 1975. Yields and solids loss in steam blanching, cooling
and freezing vegetables. J. Food Sci., 40:660.
Brown, G. E., J. L. Bomben, W. C. Dietrich, J. S. Hudson, and D. F. Farkas.
1974. A reduced effluent blanching-cooling method using a vibratory
conveyor. J. Food Sci. 38:89.
Carroad, P. A. 1975. Economic analysis of a novel method for cleaning
using rotating rubber discs. MBA thesis, University of California,
Berkeley.
Commercial Mfg. Supply Co. 1975. Catalog No. 375, Fresno, Calif.
Dietrich, W. C., and H. J. Neumann. 1968. Blanching Brussels sprouts.
Food Tech. 19(5):150.
EPA. 1971. Methods for Chemical Analysis of Water and Wastes. 16020
07/71. Environmental Protection Agency, Cincinnati, Ohio.
Johnnie, C. C., and Aggarwal, D. K. 1977. Calculating plant utility costs.
Chen-.. Eng. Progr. 73(11):84.
Layhee, P. 1975. FF line yields 5 big production benefits. Food Engin.
47(2):61.
44
-------
Lazar, M. E., D. B. Lund, and W. C. Dietrich. 1971. IQB: A new concept in
blanching. Food Tech. 25:684.
Lazar, M. E. and C. R. Rasmussen. 1964. Dehydration plant operations. In
"Food Dehydration." Avi Publishing Co., Vol. 2, p 132.
Lund, D. B. 1974. Wastewater Abatement in Canning Vegetables by IQB
Blanching. Office of Research and Development. EPA-660/2-74-006.
U.S. Environmental Protection Agency, Washington, D.C.
National Canners Association. 1971. Liquid Wastes from Canning and Freezing
Fruits and Vegetables. 12060 EDK. Environmental Protection Agency,
Washington, D.C.
Peters, M. S. and K. D. Timmerhaus. 1968. Plant Design and Economics for
Chemical Engineers, 2nd ed. McGraw-Hill, New York.
Rails, J. W. and W. A. Mercer. 1973. Low Water Volume Enzyme Deact /ation
of Vegetables Before Preservation. EPA-R2-73-198. U.S. Environmental
Protection Agency, Washington, D.C.
Rails, J. W. and W. A. Mercer. 1974. Continuous In-Plant Hot-Gas Blanching
of Vegetables. EPA 660/2-74-091. U.S. Environmental Protection Agency,
Corvallis, Oregon.
Ray, A. 1975. Steam blancher uses 50% less energy. Journal Food Processing,
36(1) p. 64.
Sharf, J. M. 1966. Frozen fruits, vegetables, and precooked frozen foods.
In "Recommended Methods for the Microbiological Examination of Foods,"
2nd ed. p 97. American Public Health Association, New York.
Soderquist, M. R. 1975. Characterization of Fruit and Vegetable Processing
Wastewaters. WRRI-28. Water Resources Research Institute, Oregon
State University, Corvallis, Oregon.
Weckel, K. G., R. S. Rambo, H. Eloso, and J. H. von Elbe. 1968. Vegetable
Canning Process Wastes. Res. Rpt. No. 39. College of Agricultural
and Life Sciences, Univ. Wisconsin-Madison.
45
-------
APPENDIX
TABLE A-l. EQUIPMENT SETTINGS FOR SNAP BEANS
Run
No.
SB-1 to
SB -4 to
SB-1 2 to
SB -2 9
SB -30
SB-31
SB-32 to
SB -3 5
Heater*
Eccentric
Weight
Setting
SB-3 7
SB-11 7
SB-28 7
6
6
5
SB-34 3
0
Number**
of Weights
on Holder
1
1
1
1
1
1
1
1
. Holder
Time
on - off
(sec)
On continuously
"
it
20 - 10
On continuously
n
ii
11
Cooler
Eccentric
Weight
Setting
7
7
9
9
9
9
9
9
Air Flow
at Blower
0
(nr/min)
150
150
150
150
150
150
150
150
up flow in
down flow
ii n
ii n
n n
n it
M ti
n it
cooler
in cooler
it n
n n
n it
n 11
ii n
n it
* A setting of 0 gave a vibration amplitude of 0.95 cm (3/8 in.), 7 gave 0.64 cm (1/4 in.)
** With 1 weight the vibration amplitude was 0.32 cm (1/8 in.)
-------
TABLE A-2. EQUIPMENT SETTINGS FOR LIMA BEANS
Run Heater*
No. Eccentric
Weight
Number** Holder
of Weights Time
on Holder on - off
Setting
LB-1
LB-2 to LB-5
LB-6 to LB-7
LB-8 to LB-10
LB-11
LB-1 2 to LB-1 3
LB-1 4 to LB-1 5
LB-1 6 to LB-1 7
7
7
7
7
7
7
7
0
1
1
1
1
1
1
1
1
(sec)
On continuously
5 - 12.5
On continuously
it
ii
10 - 10
10 - 10
10 - 10
Cooler*** Air Flow
Eccentric at Blower
Weight
Setting
7
0
0
0
0
0
0
9
(nr/mln)
150
150
85
140
140
150
85
150
UP
it
it
"
ii
it
it
flow in
it ii
it it
ii it
ii ii
it it
it it
Down flow
cooler
11
"
"
"
it
"
in cooler
* A setting of 0 gave a vibration amplitude of 0.95 cm (3/8 in.) and 7 gave 4.8 mm (3/16 in.)
** With 1 weight the vibration amplitude was 0.32 cm (1/8 in.)
*** A setting of 0 gave a vibration amplitude of 0.96 cm (3/8 in.) and 7 gave 6.4 mm (1/4 in.)
-------
TABLE A-3. EQUIPMENT SETTINGS FOR BRUSSELS SPROUTS, CAULIFLOWER AND BROCCOLI
Run
No.
Heater*
Eccentric
Weight
Setting
Number**
of Weights
on Holder
Holder
Time
on - off
(sec)
Cooler***
Eccentric
Weight
Setting
Mr Flow
at Blower
(m3/min)
BS-1
BS-2 to BS-4
BS-5
C-l
10
10
10
Brussels Sprouts
1 10-40
1 10-40
1 10-30
Cauliflower
1 30-15
9
10
10
10
150
150
150
150
B-l
B-2
10
10
Broccoli
15 - 15
Continuous
10****
10****
150
150
* A setting of 0 gave a vibration amplitude of 0.95 cm (3/8 in.) and
7 gave 4.8 mm (3/16 in.)
** With 1 weight the vibration amplitude was 0.32 cm (1/8 in.)
*** A setting of 0 gave a vibration amplitude of 0.96 cm (3/8 in.) and
7 gave 6.4 mm (1/4 in.)
**** The setting was 2.5 cm (1 in.) beyond 10; 3.8 cm (1.5 in.) beyond
10 gave no vibration
48
-------
TABLE A-4. MATERIAL BALANCE AND WASTELOAD
Yield - Wet Weight of cooled vegetables (kg) . n_
(%) Wet Weight of raw vegetables (kg) x
Solids loss - Hydraulic load (L/kkg) TS in effluent (%)
(%) 1000 x TS in raw vegetables (%) X
Hydraulic load - Weight of effluent (kg)
X 1UUU
(L/kkg) Weight of raw vegetables (kg)
BOD - (BOD analysis in mg/L) x hydraulic (L/kkg) load x 10~6
(kg/kkg)
TOC and SS were calculated similarly to BOD
49
-------
TABLE A-5. EFFLUENT ANALYSES - SNAP BEANS
Total Solids
Raw Effluent"1" Effluent
Run Number* Veget.
<*) (%) (mg/L)
SB-1
SB-2
P
P
SB-3 P
*P
B
C
SB -4
SB-5
SB-6
SB-7
SB-8
SB-9
SB-10
SB-11
SB-1 2
SB-1 3
SB-1 4
SB-1 5
SB-1 6
SB-1 7
SB-1 8
SB-1 9
SB -20
SB-21
SB-22
SB-2 3
SB-2 4
SB -2 5
SB -2 6
SB-2 7
SB -2 8
SB-29
SB -30
SB -31
SB-32
SB -3 3
SB-34
SB-35
SB -3 6
SB -3 7
P
P
P
P
P
P
P
P
P
P
B
B
P
B
P
B
B
B
B
B
C
B
P
C
C
B
C
C
B
B
P
C
C
C
10.
10.
10.
10.
10.
9.
10.
10.
10.
10.
11.
12.
13.
13.
9.
13.
14.
14.
15.
16.
9.
12.
15.
9.
9.
12.
10.
9.
9.
10.
9.
9.
8.
9.
10.
10.
10.
76
76
76
35
25
23
65
45
05
98
78
92
54
51
53
31
69
22
59
21
56
67
88
28
49
84
46
35
43
23
90
33
86
84
16
97
75
2
2
1
3
3
3
3
3
M
37
43
96
18
39
01
63
19
Not enough
3
79
Not enough
3
3
39
12
Not enough
_j__
effluent
31200
effluent
29700
28700
effluent
n n n
3
II
II
i n
i n
99
Not enough
3
2
"
2.
4
3
3
3
3
2
2
2
2
*
3.
3
ti
87
97
89
20
59
38
80
29
69
46
67
81
48
54
"
"
39000
effluent
"
38900
28900
29700
40000
35000
32200
36000
30500
24800
24600
26500
25700
32400
34300
SS
Effluent
(mg/L)
_ , J_
1151
1500
for sample
5610
for sample
4140
3660
for sample
n n
n n
n n
4310
for sample
n M
4300
3260
3200
4600
3390
3410
4000
3750
2600
2700
2920
4350
4300
TOC
Effluent
(mg/L)
12000
9750
9880
8680
11500
12300
11700
14600
12000
14200
12130
10700
14300
13500
10700
10500
15300
12900
12100
14600
11250
9000
8250
10800
13800
13800
BOD
Effluent
(mg/L)
15600
16200
15000
19200
25200
22200
24600
18600
23400
25800
21000
= preliminary run
= batch run
= continuous run
+ Using AOAC,
-H- Using EPA,
1965
1971
50
-------
TABLE A-6. EFFLUENT ANALYSES - LIMA BEANS
Total Solids
Raw Effluent"1" " ""
Run Number* Veget.
fat \ so/ \
\/o ) \/o )
LB-1 P 36.12
LB-2 P Run stopped
LB-3 P
LB-4 P Run stopped
LB-5 P
LB-6 P
LB-7 P 41.29
LB-8 B 40.65
LB-9 B 38.46
LB-10 C Run stopped
LB-11 C 40.86
LB-1 2 C 40.72
LB-1 3 C 41.60
LB-1 4 C 35.92
LB-15 C 36.09
LB-16 B 38.70
LB-1 7 C 41.82
Pilot
5.40
4.63
7.21
4.53
7.50
7.30
7.72
7.53
7.11
6.65
Effluent""
(mg/L)
Plant
_^
43000
71500
71800
77800
68300
69800
65400
Not enough effluent
SS
Effluent
(mg/L)
10700
5180
10800
14200
8900
17400
14800
17500
14900
27200
for sample
TOG
Effluent
(mg/L)
14300
13800
13800
18200
13800
20200
17700
19800
18300
24800
22800
BOD
Effluent
(mg/L)
18800
15600
19800
29400
21200
28800
19800
28200
Production Line
LBPL-1
blanching 36.08
cooling
LBPL-2
blanching 35.35
cooling
LBPL-3
blanching 35.37
cooling
* P = preliminary run
B = batch run
C = continuous run
PL = production line
1.14
1.69
1.24
0.238
1.54
0.542
+
++
10400
3330
12100
2390
15000
5370
Using AOAC
Using EPA,
762
280
1840
84
1830
388
, 1965
1971
3240
708
3670
230
4700
1400
5810
1700
8200
580
8500
3200
51
-------
TABLE A-7. EFFLUENT ANALYSES - BRUSSELS SPROUTS, CAULIFLOWER AND BROCCOLI
Total Solids SS TOC BOD
Raw
Run Number Veget. * +
(%) (%) (mg/L) (mg/L) (mg/L) (mg/L)
Brussels Sprouts
BS-1 P
BS-2 P 14.2 Not enough effluent for sample
BS-3 P 14.1 2.76 25800 3490 9970
BS-4 P 13.2 2.08 20740 2290 7500
BS-5 P Run stopped
Cauliflower
C-l P 8.45 Not enough effluent for sample
Broccoli
B-l P 10.1 Not enough effluent for sample
B-2 P 11.8 3.53 33300 8230 13600
* Using AOAC, 1965
+ Using EPA, 1971
52
-------
TABLE A-8. CALCULATION OF THEORETICAL STEAM FLOW REQUIRED FOR BLANCHING
Conditions:
Raw vegetable temperature - 16°C
Blanched vegetable temperature - 88°C
Heat of condensation of steam - 2256 kJ/kg
With no heat losses:
Heat in from condensing steam = heat out with product
Theoretical steam = (4.19)(88 - 16) 100Q
requirement 2256
_ 134 kg steam
kkg raw vegetable
For Hot-Gas Blancher (Rails & Mercer, 1974) blanching peas:
x
Steam use = 170 kg/kkg
Natural gas = 1.64 m /kkg
1.64 x 37.300 kJ/m = 61100 kJ/kkg
steam equivalent = 61100/2256 = 27.1 kg/kkg
Electrical power = 91.4 MJ/kkg , -
(circulating fan) steam equivalent = 91.4 x 10 /(2256 x 10 ) =
40.5 kg/kkg
Total steam equivalent = 170 +27.1 +40.5 = 238 kg/kkg
Efficiency - 134 1(X) , 56%
53
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-600/2-78-206
3. RECIPIENT'S ACCESSION-NO.
4. TITLE AND SUBTITLE
VIBRATORY SPIRAL BLANCHER-COOLER
5. REPORT DATE
September 1978
issuing date
6: PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
J.L.Bomben, J.S.Hudson, W.C.Dietrich,
E.L.Durkee, D.F.Farkas
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
USDA-SEA
Western Regional Research Center
800 Buchanan Street
Berkeley, CA 94710
10. PROGRAM ELEMENT NO.
1BB610
11. CONTRACT/GRANT NO.
S-803312
12. SPONSORING AGENCY NAME AND ADDRESS
Industrial Environmental Research Laboratory
Office of Research and Development
U.S. Environmental Protection Agency
Cincinnati , Ohio 45268
13. TYPE OF REPORT AND PERIOD COVERED
FINAL REPORT 7/74-1/77
14. SPONSORING AGENCY CODE
EPA/600/12
15. SUPPLEMENTARY NOTES
16. ABSTRACT
The objective of this demonstration project was to test the commercial feasi-
bility of the vibratory spiral blancher-cooler, a newly designed steam blancher and
air cooler that previous small scale tests showed could reduce the wasteload and
energy consumption of preparing vegetables for freezing.
The results of these protype tests showed the following:
1. The unit reduced the hydraulic wasteload of conventional blanching and
cooling by several orders of magnitude and the organic wasteload by as
much as 80%.
2. The steam efficiency of the blancher was 85%, which exceeds by 17 times
that measured for a conventional stean blancher.
3. Sensory tests were done only with the snap-beans and lima beans. Those
samples produced by the vibratory spiral blancher-cooler were judged either
equal or superior in flavor and texture to those conventionally blancher
and cooler.
17.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS C. COS AT I Field/Group
Food Processing
Vegetables
Freezing
Economic Analysis
Process Modification
Blanching
Wastewater Characteristi
68 D
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
19. SECURITY CLASS (ThisReport)
UNCLASSIFIED
21. NO. OF PAGES
64
20. SECURITY CLASS (Thispage)
UNCLASSIFIED
22. PRICE
EPA Form 2220-1 (9-73)
54
*U.S.60VB»«eilH»m«OFnCfc 1971-657-060/1488
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