EPA R2-73-198
MAY 1973 Environmental Protection Technology Series
Low Water Volume Enzyme Deactivation
of Vegetables Before Preservation
Office of Research and Monitoring
U.S. Environmental Protection Agency
Washington, D.C. 20460
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and
Monitoring, Environmental Protection Agency, have
been grouped into five series. These five broad
categories were established to facilitate further
development and application of environmental
technology. Elimination of traditional grouping
was consciously planned to foster technology
transfer and a maximum interface in related
fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4. Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL
PROTECTION TECHNOLOGY series. This series
describes research performed to develop and
demonstrate instrumentation, equipment and
methodology -to repair or prevent environmental
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.
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EPA-R2-73-198
May 1973
LOW WATER VOLUME ENZYME DEACTIVATION
OF VEGETABLES BEFORE PRESERVATION
by
Dr. Jack W. Rails
Mr. Walter A. Mercer
Project 12060 PAV
Project Officer
Mr. Harold W. Thompson
Pacific Northwest Environmental Research Laboratory
Corvallis, Oregon 97330
Prepared for
OFFICE OF RESEARCH AND MONITORING
U.S. ENVIRONMENTAL PROTECTION AGENCY
- WASHINGTON, D.C. 20460
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402
Price 90 cents domestic postpaid or 66 cents QPO Bookstore
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EPA Review Notice
This report has been reviewed by the Environmental Protection Agency
and approved for publication. Approval does not signify that the con-
tents necessarily reflect the views and policies of the Environmental
Protection Agency, nor does mention of trade names or commercial
products constitute endorsement or" recommendation for use.
-11-
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ABSTRACT
Four pilot-plant units were operated with asparagus, peas, corn,
beans, beets, pumpkin, and spinach to establish the potential for
new blanching systems with low wastewater generation, The
systems investigated were microwave, hot-gas, steam and hot-
water.
Single runs of about one hour duration were made for each commodity
with each blanching system. Wastewater volume was measured and
samples were analyzed for COD, SS, and pH. The most striking
result obtained was the small volume of steam condensate formed
during hot-gas blanching.
Canned samples of vegetable material from each blancher were prepared
for quality evaluation after storage. Taste panels showed no significant
flavor preference for samples from any individual blanching system. The
system used had no significant effect on the vitamin and mineral retention
of blanched or canned samples. The oxygen content of canned samples
was lowest for hot-gas blanching compared to the other three systems.
Estimates of the cost of blanching using commercial-scale units gave
(do liars/ton blanched): microwave, 18. 47; hot-gas, 3.39; steam, 2.21;
and hot-water, 2. 36.
This report was submitted in fulfillment of Project Number 12060 PAV
under the sponsorship of the Office of Research and Monitoring, U.S.
Environmental Protection Agency and the National Canners Association,
Western Research Laboratory, Berkeley, California.
-111-
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CONTENTS
Section Page
I Conclusions 1
n Recommendations 3
III Introduction 5
IV Experimental Plan 7
Blanching 7
Product Evaluation 12
Statistical Evaluation 14
Economics 14
V Experimental Results 17
Blanching 17
Product Evaluation 28
Economics 38
VI Discussion 41
VII Acknowledgements 47
VIII Literature Cited 49
IX Publications and Patents 5]
X Glossary 53
XI Appendices 57
-v-
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FIGURES
No. Page
1 Percent of Total BOD Due to Blanching 5
2 Microwave Blancher 7
3 Hot-Gas Blancher 8
4 Hot-Water and/or Steam Blancher 10
5 Pilot Blancher Installation 11
-vi-
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TABLES
No. Page
1 Schedule of Analysis for Vitamins 14
and Minerals
2 Long Term Blanching Runs for Green Asparagus 17
3 Wastewater Volume and Characteristics 18
for Green Asparagus Blanching
4 Long Term Blanching Runs for Green Peas 19
5 Wastewater Volume and Characteristics for 20
Green Pea Blanching
6 Long Term Blanching Runs for Cut Green Beans 21
7 Wastewater Volume and Characteristics for 21
Cut Green Bean Blanching
8 Long Term Blanching Runs for Corn-on-Cob 23
9 Wastewater Volume and Characteristics for 23
Corn-on-Cob Blanching
10 Long Term Blanching Runs for Red Beets 24
11 Wastewater Volume and Characteristics for 24
Red Beet Blanching
12 Long Term Blanching Runs for Pumpkin Pieces 25
-Vll-
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No. Page
13 Wastewater Volume and Characteristics for 26
Pumpkin Piece Blanching
14 Long Term Blanching Huns for Spinach 27
15 Wastewater Volume and Characteristics for 27
Spinach Blanching
16 Taste Panel Evaluation of Canned Samples After 28
Storage for Six Months
17 Quality Scores for USDA Grading of Canned 30
Vegetables
18 Headspace Gas Analysis of Canned Vegetables 31
Stored Six Months
19 Estimation of Extent of Internal Corrosion of 33
Cans Used to Store Vegetables for Six Months
at 65-85 °F
20 Vitamin Content of Raw, Blanched, and Canned 36
Vegetables
21 Mineral Content of Haw and Blanched Vegetables 37
22 Summary of Cost Estimates for Four Commercial 38
Scale Blanching Systems
23 Comparison of Peroxidase Inactivation and 42
Residence Times for Blanching of Vegetables
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No. Page
24 Wastewater Generation During Vegetable 44
Blanching
25 Pounds of COD and SS Produced During 45
Vegetable Blanching
-iX-
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SECTION I
CONCLUSIONS
1. Two relatively new blanching systems, microwave and
hot-gas, show promise for reducing enzymatic activity
and removing occluded gases in asparagus, peas, beans,
corn, beets, pumpkin and spinach.
2. The use of microwave blanching of vegetables reduces the
volume of wastewater formed substantially, but the capital
costs are too high for a seasonal operation.
3. A new method of blanching, now called "hot-gas blanching"
shows exceptional promise in reducing wastewater volume
to very low levels while providing commercially acceptable
blanching.
4. The flavor of hot-gas blanched vegetables, preserved by
canning, was not significantly different from the flavor of
samples prepared by microwave, steam and hot-water
blanching.
-1-
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SECTION II
RECOMMENDATIONS
1. Hot-gas blanching of major-use vegetables should be investi-
gated on an in-plant, continuous basis.
2. The hot-gas blanched vegetables investigated on an in-plant,
continuous basis should be returned to commercial production
either mixed or unmixed with conventionally blanched material.
3. The commercial product containing all or partially hot-gas
blanched vegetable should be marketed in such a way that
consumer reaction to the quality can be evaluated.
4. The interest of all potential equipment suppliers should be
encouraged so the design and production of commercial-scale
hot-gas blanchers will move forward rapidly if in-plant trials
are successful.
-3-
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SECTION
INTRODUCTION
The heating of vegetables prior to terminal preservation by freez-
ing, canning, or dehydration is an essential operation for satisfac-
tory final product quality (1). This blanching treatment produces
several desirable changes in the raw vegetables. Primarily, en-
zymes are thermally inactivated to stabilize the food components
against rapid chemical changes. Gases, most importantly oxygen,
are displaced from the food during blanching. For several veg-
tables, the blanching step results in physical changes in the veg-
table which improves subsequent operations such as washing,
peeling, or filling into containers. The blanching step may provide
a useful removal of certain contaminants on, or in, the raw food.
The disadvantages in vegetable blanching using steam or hot-water
are loss of nutrients and the formation of large volumes of high-
strength liquid wastes. Surveys (2) of canneries have indicated
that an average of 40 percent of the total BOD in the liquid waste
from vegetable processing results from hot-water or steam blanch-
ing (Figure 1).
ASPARAGUS
BEANS, SNAP
BEETS (& PEELING)
CORN
PEAS
PUMPKIN
SPINACH
33
80
50
Figure 1. Percent of Total BOD Due to Blanching
-5-
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New methods of blanching which generate lower volumes of liquid
wastes during vegetable processing would have obvious advantages
for environmental protection.
Blanching methods that minimize generation of liquid waste require
heat transfer media of controlled low water content. Since vegeta-
bles are 70-92 percent water, the key to low wastewater blanching
is adequate heat transfer with minimal condensate from the water
in the vegetable or from injected steam,
The present practice of the vegetable preservation industry is to
use hot-water or steam blanching. Relatively little research and
development effort has been devoted to new or modified blanching
systems which would reduce the volume of liquid waste generated.
Two recent innovations in vegetable blanching methods have promise
of substantial reductions in wastewater volume. However, neither
of these systems {jfluidized bed blanching (3) or IQB (4) ~] appear to
have the potential for almost complete elimination of wastewater.
Two methods of blanching which have potential for low wastewater
volume generation were chosen for a comparative study along with
hot-water and steam blanching. One method, microwave blanching,
has had prior investigation with several vegetables: corn-on-cob
(5, 6), brussel sprouts (7) and potatoes (8). None of these earlier
studies were as comprehensive as those planned in this current
study. The second blanching system proposed for this study was a
completely new method called hot-gas blanching which is based on
the direct use of hot natural gas combustion products as the major
heat source for increasing the temperature of the vegetables being
blanched.
Therefore, the objectives of this study were to compare the traditional
methods of vegetable blanching (hot-water or steam) with a partially
evaluated (microwave) method and a new (hot-gas) method with the
expectation of demonstrating feasibility of a low waste-water volume
blanching system which gave adequate product quality and retention
of nutrients. The four blanching systems studied were compared by
measuring operational factors, pollutional potential, product quality,
and cost estimates.
-6-
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SECTION IV
EXPERIMENTAL PLAN
BLANCHING
To evaluate the potential usefulness of microwave and hot-gas
blanching of seven major vegetable commodities, simulators of
possible commercial-scale units were operated in conjunction
with simulators of commercial hot-water and steam blanching
equipment.
The microwave unit used in this study was a Varian Model COS 5A
Microwave Conveyor shown schematically in Figure 2. The specifi-
cations for the microwave blanching unit are tabulated in Appendix A.
PRODUCT IN
PRODUCT OUT
Figure 2. Microwave Blancher
-7-
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The hot-gas blanching unit was designed, at the request of the
National Canners Association, by Magnuson Engineers, Inc. , and
fabricated by Heat and Control, Inc. Outline drawings .of the hot-gas
blancher are shown in Figure 3.
PRODUCT OUT
PRODUCT IN
4"VENT
ACCESS OPENINGS
1" STEAM INLET
7VzHP. 230/450 3PH. 60 Hz
1755 RPM
COMBUSTION AIR BLOWER
230/460 V. 3PH. SO Hz 500 WATTS
193 Vz"
V4 HP. O.C. CONVEYOR DRIVE.
1ZOV. 60Hz A.C.ISKVAPOWER
SUPPLY AT OPERATOR'S CONTROL/
POWER UNIT.
7VzHR 330/460 3 PH. 60 Hz
1755 RPM /
^_.« J J..,— -.,__
1* STEAM INLET
COMBUSTION AIR BLOWER
Z30/460V. 3PH. 60Hz
500 WATTS
Figure 3. Hot-Gas Blancher
-8-
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The specifications of the hot-gas blancher are shown in Appendix B.
The hot-gas blancher generates a mixture of hot nitrogen, carbon
dioxide and water ( supplemented on occasion by injected steam )
which is blown past the vegetable pieces as they are conveyed through
the high temperature zone. The temperature of the vegetable pieces
is raised by transfer of heat from the hot-gas mixture until a tem-
perature is achieved which will thermally inactivate enzymes and
drive off occluded gases. At this point, the heated vegetables are
discharged to an ambient temperature zone and are conveyed to a
filling line for canning or to a cooling line for frozen products. If
sanitary conditions are maintained in the hot-gas blancher, no fur-
ther washing of the blanched product before canning is required.
The steam and hot-water blanching was simulated in a single unit
which was the third stage of the pilot washer provided to the National
Canners Association under U.S. Atomic Energy Commission Contract
AT ( 04-3 ) - 536. Line drawings for the steam and hot-water blancher
are shown in Figure 4. The specifications for the steam and hot-
water blancher are listed in Appendix C. The commercial practice
of the vegetable preservation industry is to use hot-water or steam
for blanching. Hot-water is an effective blanching medium due to
its exceptional heat transfer properties, its cleansing action on soiled
vegetables and its ease of temperature control. Steam blanching is
used less frequently than hot-water blanching, usually in those cases
where a quality factor ( taste, color, texture ) is improved by the use
of steam.
Raw vegetables were donated by member canners and were transported
by refrigerated truck to the Berkeley Laboratory where the blanching
simulators were installed. A series of short duration experiments
were conducted over a range of operating conditions for each blanch-
ing-unit to determine good operating conditions. The conditions selec-
ted for longer duration experiments were based on weight changes,
product appearance and residual peroxidase levels. The peroxidase
measurement involved measuring color generation over a period of
ten minutes. The plot of time versus optical density gave a line whose
slope corresponded to residual peroxidase content (5).
-9-
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DRIVE UNIT SUPPORTED
FROM CONVEYOR CHASSIS.
SEPARATE REMOVABLE
COVERS.
VENT
CO
PRODUCT IN
2 HEADERS, SIDE BY SIDE, WATER, STEAM
PIVOT POINT FOR \
ONVtVOR CHASSIS \
WHITE NEOPRENE
CURTAINS
v jjj - v ..... ><..e.k...r I ^
: : : : : : : : : " : V ..••'" « \ ,;* "4 ..''5 + ^
':•"••' ' ' " ••-• • ,,... »»....• . ^ m
PRODUCT OUT
ADJUSTABLE LEGS
THIS UNIT ONLY
99'
Figure 4. Hot-Water and/or Steam Blancher
-10-
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The unit indicated in Figure 4 was operated as a steam blancher by
passing steam into a spray h'ead manifold above the conveyor belt.
The unit was operated as a hot-water blancher by circulating a fixed
volume of water held in the blancher tank through an automatically
controlled ( steam heated ) tubular heat exchanger. A photograph of
the blanching units as they appeared during the pilot plant studies is
shown in Fi gure 5.
MICROWAVE UNIT
STEAM/HOT-WATER UNIT
.
-GAS UNIT
*~
Figure 5. Pilot Blanching Installation
-11-
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During the long duration runs, wastewater samples were collected
from each of the four blanchers. The total effluent from the micro-
wave, hot-gas and steam blancher was mea'sured for volume and a
portion analyzed. Four one quart samples of the total volume of
mixed liquid and suspended solids were taken from the hot-water
blancher at 15 min intervals. A final wastewater sample was taken
from the hot-water blancher tank at the end of each long duration
run for each of the vegetables studied. All of the wastewater samples
collected were analyzed for COD, SS and pH (9).
PRODUCT EVALUATION
Samples of blanched vegetables were prepared ( for example :
corn cutting, beet peeling, pumpkin blending and screening) and
canned for later quality evaluation. A total of five quality evalua-
tions ( taste, grading, headspace gases, internal can corrosion,
and vitamin and mineral content) were made on each set of canned
vegetable samples. Details of these evaluations are presented below.
Taste - Sets of samples of each commodity ( except peas and spinach)
were presented to a laboratory taste panel consisting of about 16
tasters. The presentation of samples in a random order was repeated
four times to obtain approximately 60 judgements. The sets of four
different samples were presented in paper cups marked L, M, N,
and O. Each panelist was asked to rank the four samples after
tasting, with "4" denoting the worst flavor, and "1" the best flavor.
It was requested that each sample be a given different ranking number
even if two or more samples tasted the same. Therefore, if four
identical samples were judged, the cumulative average score for a
large number of judgements would be "2. 5. " A scoring sheet used
to record the ranking of samples is shown in Appendix D.
Grading - A second evaluation of the canned samples was made by
experienced quality graders from the U. S. Department of Agriculture
Processed Fruit and Vegetable Inspection Division. The samples
were shipped to Stockton, California from where they were distributed
by the USDA to individual inspectors. This quality grading developed
a number reflecting primarily the appearance of the sample.
-12-
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Headspace Gases - Limitation of time did not permit a direct measure
of gas content of vegetables immediately after blanching. An analysis
was made of headspace gas in cans representing each blanching var-
iable for each commodity. The method used was^essentially that des-
cribed in the NCA Laboratory Manual for Food Canners and Processors
(10) with the modifications listed in Appendix E.
Internal Can Corrosion - The fourth quality evaluation was made by
visual examination of 7-14 washed and dried empty cans from each
blanching variable for extent of internal corrosion. The cans were
scored "411 if badly corroded, "3" if moderately corroded, "2" if
slightly corroded and "1" if without visible corrosion.
Vitamin and Mineral Content - The fifth quality measurement was the
determination of the level of vitamins and minerals in raw and blanched
samples of each vegetable studied, restricting the analysis to the nu-
tritionally significant components. These determinations were made
according to the Eleventh Edition of the "Official Methods of Analysis
of the Association of Official Analytical Chemists" (11:).
The selection of vitamins and minerals for analysis was based on three
sources of data:
a) Tabulations of vitamin and mineral content of raw
and processed vegetables (12, 13)
b) Official tabulations of Recommended Daily Dietary
Allowances (14)
c) Per capita consumption of processed vegetables (15)
In general, a vitamin or mineral was included in the analytical schedule
if a 100 g portion of a specified vegetable contained 10% or more of the
maximum recommended daily dietary allowance, (MRDA). In those cases
where all vitamins and minerals were below the 10% figure, a combination
of the percentage contribution to the MRDA and the per capita consumption
were used to make the selection.
The vitamin and mineral testing schedule used in this study is tabulated
in Table 1. Due to loss of samples or misunderstandings on the part of
analysts, this schedule was not followed rigorously.
-13-
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Table 1 Schedule of Analysis for Vitamins and Minerals
Vitamins
Minerals
Commodity
Niacin Ca Mg P ' Fe
Asparagus
Green Beans
Beets
Corn
Peas
Pumpkin
Spinach
No
No
No
No
.No
Yes
Yes
Yes
Yes
No
Yes
Yes
No
No
Yes
Yes
Y3S
Yes
Yes
No
Yes
No
Yes
No
Yes
Yes
No
No
Yes
No
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
No
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
No
No
No
Yes
No
Yes
STATISTICAL EVALUATION
The results of product evaluations were subjected to analysis of
variance to determine if there was a significant effect due to the
the blanching condition used in the preparation of samples on which
the measurement was made. The analysis of variance was made
using a randomized complete block design ( 16 ) with the vegetables
involved in the analysis as blocks*and the blanching conditions as treat-
ments. When the variance ratio (F value) calculated exceeded the
tabular F values at the 1 or 5 percent level of significance, multiple
range tests could be used to determine significance due to individual
blanching conditions for specific vegetables.
ECONOMICS
The cost of blanching using a new system such as microwave or
hot-gas is a critical factor in any decision to replace currently used
equipment. Therefore, a serious attempt was made in this study to
gather information on which to base cost estimates of commercial
scale equipment for microwave, hot-gas, steam and hot-water blanch-
-14-
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ing. The information on capital costs, cooling water usage, make-up
water volumes, power consumption and space requirement were ob-
tained by suppliers or potential suppliers of commercial scale equip-
ment. The operating costs were estimated from power usage and
public utility fee schedules as well as general estimates of cost of
wastewater treatment. The cost estimate was designed to represent
an unspecified commodity being blanched in a unit of approximately
5 tons/hr capacity. The uncertainties of estimation made the cost
estimate useful only as a rough screening of economic practicability
of a new blanching system before more extensive testing and collection
of cost factors were considered.
-15-
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SECTION V
EXPERIMENTAL RESULTS
BLANCHING
Asparagus - The green asparagms used in 1971 studies was obtained
from Washington State in two spaced deliveries. The stalks were
trimmed by hand to five-in. lengths ( cutting off the butt ends ). This
asparagus was blanched in three of the four units; the hot-gas blanche r
was not completely installed while fresh canning asparagus was available
in 1971. The results of the short duration blanching experiments with
asparagus are tabulated in Appendix F and include the results of ex-
periments with hot-gas blanching conducted in Stockton, California in
1972. The results of long duration blanching of asparagus are tab-
ulated in Table 2.
Table 2 Long Term Blanching Runs for Green Asparagus
Run
No.
Blan-
ching
Unit
Feed
Rate,
Lb/Hr
Feed
Time,
Min
Resi-
dence
Time, Sec
Temp,
°F
Prod
Yield, %
Perox
Inact
Slope
Raw - - - 0. 17
ASP-38 5 kw 110 45 145 144 91 0.055
Microwave +
Steam Injection
ASP-36 Steam 180 60 100 200 94 0.00
ASP-37 Hot- 120 60 90 180 104 .016
Water
TLF-4 Hot- 500 60 131 265 91 0.00*
Gas
* The peroxidase inactivation slope for 1972 raw asparagus was 0.40.
17-
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Table 3 lists the wastewater volume and characteristics for green
asparagus blanching in the four experimental units. The results of
analysis of grab samples taken from the hot-water blancher are tab-
ulated in Appendix G.
Table 3 Wastewater Volume and Characteristics for Green Asparagus
Blanching
Run
No.
ASP-38
Blan-
ching
Unit
5 kw
Micro-
wave +
Waste
Water
Vol , Gal.
1.3
COD,
mg/1
3500
SS,
mg/1
44
PH
6. 8
Steam Injection
ASP-36
ASP -37
Steam
Hot -Water
4.3
100
2500
100
40
1
6.7
7.7
TL.F-4 Hot-Gas 0 No wastewater formed
Green Peas - The green peas used for the blanching studies were Alaska
variety freezer peas taken from the flume between the third stage washer
and the hot water blancher at a commercial freezing plant. The peas had
a temperature of 70 °F as they were loaded into a refrigerated truck for
transport to the NCA Berkeley Laboratory. The peas in the lug boxes
located in the center of a stack of boxes in the truck did not lose heat
rapidly enough to avoid souring. The bulk of the soured peas were sorted
out on receipt and only the better quality material used in the blanching
experiments. The peas used were of sufficient quality to provide useful
measurement of blanching effects except for organoleptic evaluation.
The results of the short duration experiments on blanching of green peas
are tabulated in Appendix F.
-18-
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The long term blanching experiments with green peas are summarized
in Table 4.
Table 4 Long Term Blanching Runs for Green Peas
Run
No.
Raw
P-17
P-13
P-3
P-6
Blan- Feed
ching Rate,
Unit Lb/Hr
— —
5 kw 220
Microwave +
Steam Injection
Hot-Gas 710
Steam 180
Hot- 210
Water
Feed
Time,
Min
.
54
46
55
58
Resi-
dence
Time, Sec
160(15)*
206(39)*
120
90
90
Temp
o
F
150
255
180
185
Prod
Yield, %
98
99
100
99
Perox
Inact
Slope
1.8
0.60
0. 14
0. 013
0. 043
* Numbers in parentheses indicate feed time in minute's at listed
residence time
The wastewater volume and characteristics for blanching of green peas
in four experimental units is tabulated in Table 5.
-19-
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Table 5 Wastewater Volume and Characteristics for Green Pea
Blanching
Run
No.
P-17
Blan-
ching
Unit
5 kw
Waste -
Water
Vol , Gal.
4.25
COD,
mg/1
54,300
SS,
mg/1
630
PH
4.2
Microwave +
Steam
Injection
P-13
P-3
P-6
Hot -Gas +
Steam
Injection
Steam
Hot -Water
0.005
4.0
100
™
41,000
3,920
*"
3,700
170
™
4.6
4.4
Green Beans - The green beans used in the short-duration blanching
runs were obtained at a cannery in Eugene, Oregon and transported to
Berkeley in an air conditioned station wagon. The beans were pole
beans which had been snipped and size-graded. The results of the short-
duration blanching runs for green beans are tabulated in Appendix F.
The green beans used for the longer-duration runs were obtained in
Junction City, Oregon and transported to Berkeley in two air-condi-
tion station wagons. The beans were cut bush beans of Number 3
sieve size. The results for the long-term blanching experiments with
green beans are tabulated in Table 6.
-20-
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Table 6 Long Term Blanching Runs for Cut Green Beans
Run
No.
Raw
BN-26
Blan-
ching
Unit
.
5kw
Microwave
Feed
Rate,
Lb/Hr
+ 120
Feed
Time,
Min
50
Resi-
dence
Time, Sec
206
Temp
F
130
,Prod
Perox
Inact
Yield,% Slope
92
4.8
0.53
Steam Injection
BN-25
Hot -Gas +
340
60
333
250
82
0.06
Steam Injection
BN-27
BN-28
Steam
Hot Water
190
120
56
60
217
291
190
190
94
98
0.07
0.06
The wastewater volumes and characteristics from long-term blanching
of green beans are tabulated in Table 7.
Table 7 Wastewater Volume and Characteristics for Cut Green
Bean Blanching
Run
No.
BN-26
BN-25
BN-27
BN-28
Blan-
ching
Unit
5 kw
Microwave +
Steam Injection
Hot-Gas +
Steam Injection
Steam
Hot Water
Waste-
water
Vol , Gal.
2.4
0.043
4.25
100
COD,
mg/1
1,500
900
5,400
330
SS,
mg/1
46
88
100
8
PH
6.5
7.7
6.1
7.3
-21-
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Corn - The corn used in the blanching experiments was obtained
in Eugene, Oregon on September 8, 1971. The corn was shipped to
Berkeley in the husks. Commercial-scale corn husking and cutting
equipment was loaned to NCA by the Green Giant Company from their
plant in Belvidere, Illinois.
Corn was husked and a portion cut for blanching as cut kernels. In
the initial run of unwashed cut kernels through the hot-gas blancher,
about one fifth of the feed weight ( 95 Ib ) stuck on the wire mesh con-
veyor belt and caramelization of the starchy liquid adhering to the
corn kernels took place. The product recovered from the belt weighted
77 Ib ( 80% recover ). The conveyor belt was cleaned by hand brush-
ing of the moving belt ( at maximum speed setting ) with steam injec-
tion into the unit and a continuous water spray on the belt at the product
discharge end. The cleaning took 27 minutes and used 34 gal of fresh
water. The cleaning wastewater composite had a COD of 18, 000 mg/1
and a SS of 3,200 mg/1.
The lack of successful blanching of unwashed cut kernel corn with the
hot-gas blancher made it necessary ( for comparative purposes ) to
run all four blanching units using corn-on-cob. The blanched corn-on-
cob was cut for preparation of canned whole kernel corn samples.
The results of short-duration blanching runs on corn-on-cob in the
four experimental units are tabulated in Appendix F.
The results of longer-term blanching of corn-on-cob in the four exper-
imental blanchers are tabulated in Table 8.
-22-
-------
Table 8
Long Term Blanching Runs for Corn-on-Cob
Run
No.
Raw
CN-14
CN-10
CN-15
CN-12
Blan- Feed
ching Rate ,
Unit Lb/Hr
mm mm
5 kw
Microwave + 160
Steam Injection
Hot -Gas + 360
Steam Injection
Steam 220
Hot-Water 230
Feed Resi-
Time f dence
Min Time, Sec
—
60
60
60
47
.
224
330
435
437
^
Perox
Temp,Prod Inact
F Yield, % Slope
—
130
260
195
190
.
95
98
98
96
0.
0.
0.
0.
0.
110
067
022
040
067
The wastewater volumes and characteristics for longer-term blanching
of corn-on-cob are tabulated in Table 9.
Table 9 Wastewater Volume and Characteristics for Corn-on-Cob
Blanching
Blan-
Run ching
No. Unit
Waste-
water
Vol , Gal.
CN-14 5 kw 0.75
Microwave +
Steam Injection
CN-10 Hot-Gas + 0.0024
Steam Injection
CN-15 Steam 3.12
CN-12 Hot-Water 110
COD, SS,
mg/ 1 mg/ 1
4,300
500
9.400
460
73
90
4
PH
6.3
6.8
6.4
7.7
-23-
-------
Red Beets - A mixture of small and medium sized, washed, red beets
were obtained in Eugene, Oregon on September 15, 1971 and brought to
Berkeley. The results of short-duration blanching runs with beets in
the four experimental units are tabulated in Appendix F. The results of
long term blanching of beets are tabulated in Table 10.
Table 10 Long Term Blanching Runs for Red Beets
Run
No.
Blan-
ching
Unit
Feed Feed Resi-
Rate, Time, dence
Perox
Inact
Raw
BT-10
BT-7
Temp, Prod
Lb/Hr Min Time, Sec F Yield, % Slope
5 kw 240
Microwave +
Steam Injection
Hot-Gas +157
Steam Injection
30
60
93
625
130
250
100
94
1. 14
0. 105
0.045
BT-8
BT-11
Steam 142
Hot- Water 150
53
60
660
510
195
198
96
99
0.
0.
038
075
The wastewater volumes and characteristics for longer-term blanching
of beets are tabulated in Table 11.
Table 11 Wastewater Volume and Characteristics for Red Beet
Blanching
Blan-
Run ching
No. Unit
BT-10 5 kw
Microwave +
Steam Injection
BT-7 Hot Gas +
Steam Injection
Waste-
water
0. 50
0.007
COD,
320
1,500
SS
Vol., Gal. mg/1 mg/1
47
10
5.3
7.0
-24-
-------
Table 11
ContTd
Run
No.
BT-8
BT-H
Blan-
ching
Unit
Steam
Hot-Water
Waste -
water COD,
Vol , Gal. mg/1
4.75 7,200
100 370
SS,
mg/1
420
14
PH
5. 0
7. 10
Pumpkin - The pumpkins used in the blanching experiments were obtained
near Gridley, California on October 19, 1971 and transported whole to
the Berkeley Laboratory. The pumpkin was cut by hand into random-
sized pieces ( 1 in. square up to 3 in. square ) and the seeds removed.
The results of short-duration blanching runs for pumpkin are tabulated
in Appendix F. The results from the longer-term blanching experiments
with pumpkin pieces are tabulated in Table 12.
Table 12 Long Term Blanching Runs for Pumpkin Pieces
Blan-
Run ching
No. Unit
Feed
Feed Residence
Prod Perox
Rate, Time, Time, Temp, yield Inact
Lb/Hr Min Sec °F % Slope
Raw - ...
PM-13 5 kw 130 60 390
Microwave +
Steam Injection
PM-14 Hot-Gas + 130 60 625
Steam Injection
PM-15 Steam 140 60 600
PM-16 Hot-Water 120 60 510
140
250
196
210
86
93
94
7.43
94 1.22
0.079
0. 0057
0. 013
The wastewater volumes and characteristics for longer-term blanching
of pumpkin are tabulated in Table 13.
-25-
-------
Table 13 Wastewater Volume and Characteristics for Pumpkin
Piece Blanching
Run
No.
PM-13
Blan-
ching
Unit
5 kw
Waste
water
Vol, Gal.
2.5
COD,
mg/1
6,600
SS,
mg/1
84
pH
6.2
Microwave +
Steam Injection
PM-14 Hot-Gas + 0.005 140 1 6.0
Steam Injection
PM-15
PM-16
Steam
Hot -Water
4.5
110
10,400
640
48
10
6. 1
7.2
Spinach - The spinach used in blanching experiments was obtained from
Walla Walla, Washington. The spinach received at the cannery on
October 27, 1971 was destoned and washed. The washed spinach was
packed in plastic-lined lug boxes. Crushed ice was added to keep the
product cool during the transport period. The spinach arrived in Berk-
eley in excellent condition on the evening of October 29, 1971.
The results of short-duration runs for microwave and hot-gas blanching
of spinach are tabulated in Appendix F. No short-duration runs were
made for steam and hot-water blanching because bench scale work, done
earlier on samples of fresh market spinach, had established that ad-
equate peroxidase inactivation for canning could be accomplished with a
residence time of one minute at 180 F.
The results for the long-term blanching experiments with whole leaf
spinach are tabulated in Table 14.
-26-
-------
Table 14 Long Term Blanching Runs for Spinach
Run
No.
Raw
SP-1
SP-2
SP-3
SP-4
Blan- Feed
ching Rate,
Unit Lb/Hr
5 kw 38
Microwave +
Steam Injection
Hot -Gas + 140
Steam Injection
Steam 230
Hot-Water 140
Feed
Time,
Min
60
60
26
30
Resi-
dence
Time, Sec
93
164
79
66
Temp,
°F
140
250
180
180
Prod
Yield, %
63
69
91
104
Perox
Inact
Slope
0.72
0. 034
0. 004
0. 0008
0. 065
The wastewater volumes and characteristics for longer-term blanching
of spinach with the four experimental units are tabulated in Table 15.
Table
Run
No.
SP-1
SP-2
SP-3
SP-4
15 Wastewater
Blanching
Blan-
ching
Unit
5 kw
Microwave + j
Steam Injection
Hot-Gas +
Steam Injection
Steam
Hot Water
Volume and Characteristics
Waste -
Water
Vol , Gal.
0.63
0. 003
6.4
100
COD,
mg/l
280
990
4700
220
for Spinach
SS,
mg/l
37
1
210
35
PH
5.6
6.9
6. 1
6.6
-27-
-------
PRODUCT EVALUATION
The samples of canned vegetables prepared from the blanched material
from each of the four units were stored at ambient temperature in the
NCA Berkeley Laboratory for six months before any quality examin-
ation was made. The storage period was used to allow any slow chem-
ical reactions due to inadequate blanching to show up as deteriorated
product quality. Also, the storage period would allow time for any
internal corrosion to occur due to inadequate blanching.
Taste - The canned samples of green asparagus, green beans, corn,
beets and pumpkin ( as pies ) were presented to a laboratory taste panel.
The results of the taste panel evaluation are tabulated in Table 16. It
was not possible to get a taste panel results for green peas ( raw prod-
uct souring ) or spinach ( low vacuum due to excessive holding time of
hot brine filled cans before closing and retorting ).
Table 16 Taste Panel Evaluation of Canned Samples After Storage
for Six Months
Ranking Totals */Number of Judgements
Commodity
Asparagus
Microwave
Steam
Hot-Water
Commercial**
Panel
32/11
26/11
20/11
31/11
46/16
34/16
49/16
31/16
55/16
38/16
41/16
26/16
51/16
31/16
39/16
39/16
Green Beans
Microwave
Hot-Gas
Steam
Hot-Water
49/16
40/16
37/16
34/16
44/16
39/16
37/16
34/16
43/16
42/16
43/16
32/16
48/16
35/16
40/16
37/16
-28^
-------
Table 16 Cont'd
Ranking Totals */Number of Judgements
Commodity
Corn
Microwave
Hot-Gas
Steam
Hot-Water
Panel
26/16
51/16
38/16
44/16
24/15
41/15
31/15
55/15
28/16
40/16
34/16
52/16
28/16
42/16
39/16
50/16
Beets
Microwave
Hot-Gas
Steam
Hot-Water
31/14
42/14
37/14
30/14
28/16
41/16
47/16
44/16
44/16
31/16
39/16
40/16
40/16
36/16
44/16
40/16
Pumpkin ( As Pies )
Microwave
Hot-Gas
Steam
Hot-Water
41/15
28/15
28/15
43/15
48/16
37/16
39/16
38/16
35/13
29/13
28/13
38/13
41/15
31/15
43/15
34/15
The ranking totals are sums of individual rankings with
the best flavor given the lowest number.
Sample purchased at a store to complete the set of four
samples since hot-gas blanching of asparagus was not
done at the time of the preparation of the other three
samples.
-29-
-------
Grading - Canned samples of green beans, whole kernel corn, whole
beets, pumpkin and spinach prepared with microwave, hot-gas, steam
and hot-water blanching were quality graded by inspectors from the
USDA. The total scores from the grading are tabulated in Table 17
and the copies of the actual scoring sheets are in Appendix H. The
higher the score number the higher the quality of the sample being
scored.
Table 17 Quality Scores for USDA Grading of Canned Vegetables
Commodity Total Score *
Green Beans
Microwave 76
Hot-Gas 64
Steam 62
Hot-Water 72
Whole Kernel Corn
Microwave 71
Hot-Gas 75
Steam 68
Hot-Water 82
Whole Beets
Microwave 83
Hot-Gas 79
Steam 80
Hot-Water 80
Pumpkin
Microwave 78
Hot-Gas 78
Steam 85
Hot-Water 84
-30-
-------
Table 17 Cont'd
Commodity Total Score *
Spinach
Microwave 0**
Hot-Gas n**
Steam 0**
Hot-Water 0**
* Higher the score the better the product quality
** All spinach samples scored 0 due to excessive stem material
Headspace Gases - The results of analysis of headspace gases in
canned samples of vegetables are tabulated in Table 18.
Table 18 Headspace Gas Analysis of Canned Vegetables Stored
Six Months
Percent
Blanching Headspace Argon
Commodity Unit Volume, ml N2 CO2 HZ* +02
Asparagus Microwave 15.4 84 7.2 6.2 2.6
Steam 10.8 94 3.5 0.0 2.5
Hot-Water 8.6 86 3.7 6.3 4.0
Green Beans Microwave 28. 8 93 4. 8 0.2 2. 0
Hot-Gas 29.1 89 5.5 3.6 1.9
Steam 28. 7 93 4. 6 0. 3 2. 1
Hot-Water 24.4 91 5.0 2.0 2.0
-31-
-------
Table 15 Cont'd
Percent
Commodity
Spinach
Beets
Pumpkin
Green Peas
Blanching Headspace
Unit Volume, ml N2
Microwave
Hot-Gas
Steam
Hot-Water
Microwave 21.0
Hot-Gas 24. 8
Steam 17.8
Hot-Water 26. 5
Microwave 21.4
Hot-Gas 27. 0
Steam 15.3
Hot -Water 21.1
Microwave 30. 1
Hot-Gas 28. 8
Steam 31.9
Hot- Water 29. 2
89
87
92
86
74
91
93
88
90
86
90
91
93
88
90
92
CO 2
10.4
10.5
6.4
11.2
5.7
7.3
3.9
5.2
6.6
8.6
7.9
6.6
4.4
4.0
3.6
3.7
r
H2*
0.0
0.3
0. 0
0.6
18.3
0.4
0. 0
4.6
1.4
4. 1
0. 0
0.3
0. 0
0.9
2.9
0.3
Argon
+02
0.6
2.2
1.6
2.2
2.0
1.3
3. 1
2.2
2.0
1.3
2.1
2. 1
2.6
7.1
,3.5
4.0
-32-
-------
Table 18 Cont'd
Percent
Blanching Headspace Argon
Commodity Unit Volume, ml N2 CO2 H2» +02
Corn Microwave 42.9 91 3.9 0. 0 5. 1
Hot-Gas 36.0 88 7.3 0.3 4.4
Steam 38.5 92 5.8 0.3 . 1. 9
Hot-Water 37.5 92 5. 9 0. 0 2. 1
* Determined by difference
Internal Can Corrosion - The results of estimation of the extent of
internal corrosion of cans used to store thermally processed vegetables
are tabulated in Table 19.
Table 19 Estimation of Extent of Internal Corrosion of Cans Used to
Store Vegetables for Six Months at 65 - 85 F
Commodity Average Extent of Corrosion*
Asparagus
Microwave 2
Steam 2
Hot-Water 2
Commercial 3
Green Beans
Microwave 1
Hot-Gas 1
Steam 1
Hot-Water 1
-33-
-------
Table 19 Cont'd*
Commodity Average Extent of Corrosion*
Beets
Microwave 1
Hot-Gas 1
Steam 1
Hot-Water 1
Green Peas
Microwave 2
Hot-Gas 2
Steam 2
Hot-Water 2
Corn
Microwave 2
Hot-Gas 1
Steam 1
Hot-Water 1
Spinach
Microwave 1
Hot-Gas 3
Steam 2
Hot-Water 2
Pumpkin
Microwave 3
Hot-Gas 2
Steam 2
Hot-Water 2
#4 = severe; 3 = moderate; 2 = slight; 1 = no corrosion
-34-
-------
Vitamin and Mineral Content - The average values for vitamin content
of raw, blanched and canned samples of vegetables are tabulated in
Table 20. Individual results for vitamin content and related standard
deviations are tabulated in Appendix I. The average values for mineral
content of raw and blanched samples of vegetables are tabulated in
4
Table 21. Individual results for mineral content and standard deviations
are tabulated in Appendix J.
-35-
-------
Table 20 Vitamin Content of Raw, Blanched, and Canned Vegetables
Average Values in mg/lOOg
Blanched Samples
Canned and Stored ( Six Months ) Samples
Commodity
Asparagus
Green Peas
Green Beans
Corn
Beets
Pumpkin
Spinach
Vitamin
B,
BZ
C
Niacin
B,
B2
B6
C
Niacin
B,
B2
B6
Niacin
B,
B2
B6
Niacin
BZ
C
Niacin
A
Niacin
A
B2
C
*
**
Raw Microwave
.22
.22
19.
1. 55
.07
. 17
#
*#
*
*
. 13
.056
.49
*
. 12
*
1.41
. 061
6.9
.24
5.78
.49
2.30
. 072
**
Enzyme
Samples
*
. 19
14.
1.82
. 10
. 17
. 24
#*
1.93
*
. 13
.058
.64
*
. 11
#
2.23
. 054
6.8
.21
5.05
. 38
4. 02
. 15
**
used gave
lost durin
Hot-Gas
. 18
. 19
11.
. 73
. 14
. 17
.27
#*
2. 03
*
. 12
.037
.73
#
. 12
*
2. 06
. 068
7. 5
.26
4. 06
. 57
4.21
. 13
**
poor results.
g storage peri
Steam
*
. 20
22.
1.46
.07
. 13
. 32
*#
1.95
#
. 12
. 053
.56
*
. 11
*
2. 18
. 045
5.6
. 20
7.91
.26
3.63
. 10
#*
sample used
.od
Hot-Water
*
.20
18.
1.65
.06
. 15
.22
#*
1.72
*
. 12
.057
.57
*
. 11
*
1.91
. 041
7.9
.20
4.66
. 32
3.74
.073
**
up in other
Microwave
. 053
. 096
3. 8
.64
. 10
. 075
. 14
2.6
1. 1
.29
.054
. 051
.36
. 025
. 079
. 070
1. 08
. 016
4. 1
. 08
3. 74
.41
1. 57
. 11
analyses
Hot-Gas
_
-
-
-
. 11
. 082
. 15
4.7
1.2
.40
.066
. 054
. 38
.026
. 079
. 077
1. 12
. 013
5. 0
. 09
3. 09
.44
2. 25
. 096
Steam
. 051
. 090
3.6
.76
. 10
.067
. 10
3.9
.92
.30
.060
.048
.35
. 026
.077
. 072
1. 07
.014
4. 1
. 11
2. 98
. 33
3.26
. 081
Hot-Water
. 057
. 11
3.6
. 72
. 089
. 068
. 11
3. 1
.91
.29
.056
. 059
. 32
. 023
. 071
. 073
.95
. 023
4. 8
. 09
5. 22
.28
4. 46
. 089
-------
Table 21 Mineral Content of Raw and Blanched Vegetables
Average Values in mg/lOOg
Blanched Sample
Commodity
Asparagus
Green' Peas
Green Beans
-j
i
Corn
Beets
Pumpkin
Spinach
Mineral
Ca
Mg
P
Ca
Mg
P
Fe
Ca
Mg
P
Fe
P
P
Ca
Mg
P
Ca
Mg
P
Fe
Raw
21.2
15.7
67.0
*
*
#
*
40.0
27.0
36.0
1.25
83.0
22.7
9.2
6.7
11.6
62.2
63.5
20.0
3.1
Microwave
22. 1
15.5
77.0
14.2
28.5
104.
1.03
45. 8
29.3
40.0
1.32
91.3
26. 0
8.8
12.9
21.5
86. 0
89.5
50.2
3.4
Hot -Gas
19.3
15.2
61.5
14.-*
29.1
114.
1.06
52.0
33.1
48.0
1.54
79.0
26.6
13.5
10.9
13.9
68.0
65.0
42. 5
3.2
Steam
22.0
14.4
70.0
13.0
27.6
101.
.99
39.2
26.5
36.0
1.24
90.0
23.4
10.7
9.6
14.2
65.0
65.5
42. 5
3.3
Hot -Water
20.2
16.4
69. 5
14.2
28.3
98.
1. 04
40.6
27. 1
38.4
1. 19
*
21.2
9.2
7.2
9.7
50. 5
49. 0
31.4
3. 1
* Sample lost
-------
ECONOMICS
The detailed cost estimate for vegetable blanching with the four
systems used in this study are tabulated in Appendix K. A summary
of the cost estimates is tabulated in Table 22.
Table 22 Summary of Cost Estimates for Four Commercial
Scale Blanching Systems*
Hot-Gas
Microwave
Hot -Water
Steam
Cost/Ton
Fixed Cost**
2. 19
14.72
1.26
1. 11
Blanched, Dollars
Operating***
1.20
3.72
0.87
0.95
Waste
Management
. 00
. 03
.23
. 15
Total
3.39
18.47
2.36
2.21
* Based on 5 tons/hr, 1800 hr season
** Capital costs include: amortization, interest, space rent,
taxes, insurance, maintenance
*** Operating cost-4 include: electric power, steam consumption,
gas consumption, water use, part replacement when applicable,
and labor.
The assu^pt-ons used in making the cost estimates were the following:
Blancher capacity -- Five tons/hr.
-38-
-------
Annual operating period -- Five week season for each of three commod-
ities. Six day work week with blanchers operating 20 hr. day. Therefore,
the total operating period annually would be 3 x 5 x 6 x 20 or 1800 hr.
First cost -- The purchase price of commercial scale blanchers
supplied by manufacturers of food processing equipment. The purchase
price of the microwave blancher included the cost of a cooling tower
for removing heat from the water used to cool the power tubes.
Amortization -- Defined as the capital recovery factor (erf) and assum-
ing 7 percent interest, 5 year amortization period and no salvage value.
Space rent -- This was set at $12. 00/sq ft/year. One thousand sq ft was
provided for the microwave unit due to the space required for the wave
generating unit in addition to the blancher space requirement. Five
hundred sq ft was provided for the other three blanching units. Boiler
space requirements were ignored since all four units require steam.
Taxes -- These were set at $5. 00/$100. 00 of assessed value based on
25 percent of market value.
Insurance_-- This was set at 0.2 percent of assessed value/year.
Maintenance -- This can only be roughly estimated since this factor
varies with the complexity of the equipment and with the care in which
it is operated. The estimates used ranged from 1 to 2. 5 percent of
first cost/year.
Electrical power -- A rate of $. 035/kwh was used for the hot-gas,
steam and hot-water blanchers and a rate of $. 0125 lor the microwave
blancher due to its much larger power requirements. All rates were
obtained from Pacific Gas and Electric Company General Service
Schedule No. A-l.
Steam consumption -- The steam required by the microwave blancher
was the figure provided by the Varian Corporation and that required
for the hot-gas blancher roughly estimated since no steam flow me^er
was used with the experimental unit.
For the hot-water and steam blanchers, steam consumption was
calculated from the following formula (17);
-39-
-------
S = 5.5 C ( T2 - Tl )
E
where:
S = steam requirement ( brake horse power )
C = process rate ( tons/hr )
T2 = steam temperature ( F )
o
Tj = temperature of incoming product ( F )
E = efficiency
It should be noted that the above formula yields only a estimated
steam consumption. The blancher efficiencies were arbitrarily
selected to represent mean efficiencies over a range of 30-90 percent
with the consideration that hot-water blanchers are more efficient
than steam blancher s. Blancher efficiency is dependent on character-
istics such as wall insulation and venting and thus is difficult to
estimate.
Natural gas - - The cost was taken from the Pacific Gas and Electric
Company Schedule referred to above.
Water -- The figure of $ . 10/100 cu ft was obtained from the Varian
Corporation as the cost of make-up water for the cooling tower losses.
The estimate of 10 gpm of make-up water for the hot-water blancher
was provided by the FMC Corporation.
Waste disposal -- The figure of $. 05/lb for BOD and SS removal was
obtained from a report prepared by NCA for the U.S. Environmental
Protection Agency (2). Amounts of waste were determined from the
studies described above and represent averages of runs involving seven
vegetables. The values used only approximate those expected from
commercial blanching operations.
Labor -- Figures of $ 4/hr plus $ .40/hr benefits were used to cal-
culate costs. Due to the complexity of the microwave and hot-gas
units ( primarily the control requirements ) it was estimated that each
unit would require one worker. For the steam and hot-water blanchers
provision was made for a half-time worker.
-40-
-------
SECTION VI
DISCUSSION
The objectives of this study were to test the feasibility-of one new (hot-
gas) and one partially investigated (microwave) blanching system as
replacements for the currently used hot-water and steam blanching
systems. The overall feasibility was determined by examining, in
sequence, the factors of peroxidase inactivation, blanched product
appearance and texture, wastewater generation and characteristics,
product quality and cost estimates. The feasibility of the proposed
replacement systems could have been eliminated at any of the stages
of the testing program. For example., at the start of the study there
was no assurance that hot-gas blanching would reduce peroxidase levels
in a given vegetable using practical residence times and operating
temperatures.
The fact that the blanching units used in this study were simulators of
possible commercial scale equipment must be emphasized. While every
effort was made to operate the simulators as closely as possible to
commercial conditions, it should be obvious that the results obtained
are only approximations of an actual commercial result. Also, after
a few initial experiments with microwave and hot-gas blanching it was
apparent that steam injection was required to get the most effective
use of energy inputs and to avoid dehydration of the raw vegetable.
Therefore, the microwave and hot-gas blanching systems were not
"pure" systems but operationally were "mixed" systems more properly
termed microwave-steam or hot-gas-steam, respectively. For purposes
of brevity, the simple designations of microwave and hot-gas are used
in this report but it should be understood that steam was injected in
the majority of experimental runs.
The first consideration in the text of feasibility of microwave and hot-
gas blanching was the degree of peroxidase inactivation which could be
achieved at reasonable residence times. The extent of peroxidase in-
activation found in samples collected near the mid-point of the long
duration runs are tabulated in Table 23 with the residence times shown
in parentheses.
-41-
-------
Table 23 Comparison of Peroxidase Inactivation and Residence Times
for Blanching of Vegetables
Percent Peroxidase Inactivation at
(Minutes of Residence Time)
Commodity
Asparagus
Peas
Beans
Corn
Beets
Pumpkin
Spinach
Microwave
67
66
89
39
91
84
95
(2.
(3.
(3.
(3.
(1.
(6.
(1.
4)
0)
4)
7)
5)
5)
5)
Hot-Gas
100
92
99
80
96
99
99
(2
(2
(5
(5
(1
(1
(
•2)
.0)
.6)
.5)
0.4)
0.4)
2.7)
Steam
100 (
99 (
99 (
1.7)
1.5)
3.6)
64 (7.2)
97 .(
100 (
100 (
11. 0)
10.0)
1.3)
Hot-Water
90
98
99
39
93
100
91
(1.
(1.
(4.
(7.
(8.
(8.
(1.
5)
5)
8)
3)
5)
5)
1)
The target peroxidase inactivation value selected for this study was 90
percent. This value, which represents a residual peroxidase content of
10 percent, was chosen since such as extent of inactivation would be
satisfactory for a canned final product. Essentially complete peroxidase
inactivation would be required for frozen preservation. r Many of the short
duration runs tabulated in Appendix F lists blanching conditions which
produce 100 percent peroxidase inactivation and would be useful for blan-
ching of vegetables to be preserved by freezing.
The extent of peroxidase inactivation resulting from microwave blanching
showed the greatest variability from vegetable to vegetable. The average
extent of peroxidase inactivation was lower for microwave blanching than
for the other three blanching methods. This observation of variability of
extent of peroxidase inactivation suggests that the energy produced fluc-
uates during different periods of operation at the same settings of the
-42-
-------
dials on the control panel of the microwave blancher. The microwave
blancher appeared to be more effective with the large piece size veg-
etables such as beets and pumpkin than with smaller sized vegetables
such as peas.
The hot-gas blancher was the most reliable of the two newer blanching
systems in reducing peroxidase levels at residence times similar to
those used for steam and hot-water blanching. The only low value found
for hot-gas blanching ( 80 percent for corn-on-cob ) was still consider-
ably higher than the value found for steam and hot-water at somewhat
longe:r residence times. It can be concluded that hot-gas blanching has
the potential of reducing peroxidase levels to useful degrees at practical
residence times.
The appearance, softening, wilting and wrinkling of vegetables blanched
by the hot-gas unit, with the exception of cut kernel corn, were satisfac-
tory and no different from the changes caused by steam or hot-water blan-
ching. There were no observations made on hot-gas blanched samples
which indicated a potential difficulty in a subsequent operation such as
peeling, cutting, blending or filling into containers.
One of the most important parts of this study was the measurement of
wastewater volume and characteristics. The primary motivation for
examining the feasibility of potential replacement blanching systems was
the need for reduction of wastewater generation during vegetable blanching .
The volume of wastewater generated for each of the seven vegetables
during blanching with the four units are tabulated in Table 24. Inspection
of the data in Table 24 leads to the conclusions that wastewater volume is
about the same for microwave and steam blanching and both of these are
significantly smaller than the volume from hot-water blanching. The most
striking conclusion is the very large reduction in wastewater volume from
hot-gas blanching compared even to the volume from steam blanching. It
can be concluded that hot-gas blanching is truly a low volume liquid efflu-
ent blanching system.
-43-
-------
Table 24
Waste-water Generation During Vegetable Blanching
Waste-water Volume, Gal/Ton
Microwave Hot-Gas Steam Hot-Water
Vegetable
Asparagus
Peas
Beans
Corn
Beets
Pumpkin
Spinach
32
43
48
9.4
8.3
84
33
0
0.018
0.25
0.013
0.087
0.076
0.043
48
48
48
28
77
64
130
1700
1000
1700
1200
1300
1800
2900
The low volume of liquid effluent product by hot-gas blanching results
in high concentrations of COD and SS in the wastewater. Therefore,
it is important to compare the pounds of COD and SS produced during
blanching since these values are related to the treatment required to
avoid potential water pollution. Table 25 tabulates the pounds of COD
and SS produced per ton of vegetable blanched with each of the four units,
It can be seen from the data in Table 25 that for all practical purposes
the hot-gas blancher produces insignificant amounts of COD and SS.
This result was the most significant finding in the study.
-44-
-------
Table 25
Pounds of CCD and SS Produced During Vegetable
Blanching
Microwave
Commodity COD SS
Asparagus . 9 . 012
Peas 20 . 22
Beans . 60 . 018
Corn . 34 . 0057
Beets . 02 . 0033
Pumpkin 2. 1 . 027
Spinach . 077 .010
* Any value less than 0. 001 was
Lb/Ton Blanched
Hot-Gas- Steam Hot-Water
COD SS COD SS COD SS
00 10 .016 1.4
16 1. 5 32
.002 0 2.2 .04 4.7
0 0 2.2 .021 4.6
.001 0 4. 6 .27 4.0
0 0 5. 6 .026 9.6
0 0 5.1 .23 5.3
considered equivalent to zero
.014
1.4
. 11
. 04
. 15
. 15
.85
The above discussion has concluded that hot-gas blanching is effective in
reducing enzyme activity of vegetables without significant generation of
liquid waste. "The next factor to consider in determining overall feasibility
was product quality. The results for taste, grading, headspace gases,
internal can corrosion and vitamin and mineral content were subjected to
analysis of variance. In none of the five product quality categories was
there a statistically significant difference due to the blanching treatment
received. This result means that hot-gas blanching produces a final prod-
uct at least equivalent in quality to products produced using microwave,
steam and hot-water blanching.
-------
The final stage of determination of overall feasibility is cost estimation.
The cost estimation is based on a summation of individual estimates and
its usefulness is related to the validity of the individual estimates. The
major source of possible error in the cost estimates occurs in the estimate
of first cost for the hot-gas blancher. The figure of $50, 000 which was
used in the cost estimate was obtained from a potential supplier of hot-gas
blanching equipment and was based on a limited engineering design con-
sideration. The experimental hot-gas blancher used in this study, which
had an average capacity of 500 Ib/hr, cost $20, 500. It did not seem real-
istic to use a simple scale-up factor of 20 to estimate the cost of a 5 ton/hr
hot-gas blancher ( $410, 000 ) since much of the cost was due to custom
design and fabrication. In-plant studies with the hot-gas blancher, after
completing the pilot-plant study, have suggested that the large blower
does not accomplish movement of the vegetable pieces. It is possible that
a simplified hot-gas blancher, which depends on convection currents to
expose the vegetable pieces to hot combustion products, would be less
costly. Therefore, this amount of $50, 000 was used as the first cost for
a commercial scale hot-gas blancher.
The amounts tabulated in Table 22 for cost of blanching show hot-gas blan-
ching, while more costly, is not prohibitively expensive. In view of the
uncertainty of the cost estimate, further investigation of hot-gas blanching
is desirable to develop more accurate cost factors.
The most significantly different cost factor is comparing hot-gas blanching
with steam and hot-water blanching is in waste management. Hot-gas
blanching may be more attractive economically in the next few years as
waste treatment costs increase as the national goal of zero discharge of
pollutants by 1985 is approached. The very small volume of liquid effluent
produced during hot-gas blanching make it an excellent choice as part of
closed loop technology.
The cost of waste treatment is going to increase as the percent removal
of BOD and SS increases. For those processors discharging into municipal
treatment systems, an increase in treatment level will increase the sur-
charges paid by the industrial discharger. It is likely that waste manage-
ment costs will increase substantially; this will make hot-gas blanching
economically more competitive with steam or hot-water blanching.
-46-
-------
SECTION VII
ACKNOWLEDGEMENTS
A number of individuals and government agencies and companies were
very generous in support of this project by supplying equipment, raw
vegetables, containers, information or editorial advice. The agencies,
companies and individuals whose contribution made this project possible
are:
U. S. Environmental Protection Agency, Kenneth A. Dostal, Harold W.
Thompson, Corvallis, Oregon.
Green Giant Company, Willard R. Brosz, John L. Welch, Le Sueur,
Minnesota and Robert L. Shaffer, Belvidere, Illinois.
Diamond Fruit Growers, Charles L. Beadsley, Hood River, Oregon,
Howard Blackley, Vancouver, Washington, and Logan Cavanaugh, Grand-
view, Washington.
Tillie Lewis Foods, Inc. , Harry Rosen, Ed Harmon, Stockton, California.
Lamb Weston, Inc. , Bruce H. Morgan, Portland, Oregon and Howard
Rice, John Hendricks, Weston, Oregon.
Agripac, Inc. E. E. Pitkin, Alton C. McCully, Eugene, Oregon.
Libby, McNeill & Libby, James J. Albrecht, Randy Johnson, Donald T.
Stevens, Chicago, Illinois, James M. Smethers, Gridley, California and
Robert Wapple, Yuba City, ^California.
Rogers Walla Walla, Inc. , William Lawr, Bud Arnold, Richard Volman,
Irene Blake, Walla Walla, Washington.
U. S. Department of Agriculture, Robert P. Graham, Charles Huxsoll,
Douglas Homnick, Albany, California, Raymond D. McHenry, San Fran-
cisco, California, Raymond Hartwig, B. P. Eisner, Leo Boire, Stockton,
California.
-47-
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SECTION VIII
LITERATURE CITED
1. Potter, N.N., Food Science, The AVI Publishing Company,
Westport, Connecticut ( 1968 ).
2. Anon. , "Liquid Wastes from Canning and Freezing Fruits
and Vegetables, " U. S. Environmental Protection Agency
Water Pollution Control Research Series 12060 EDK 08/71
( 1971 ).
3. Mitchell, R. S. , Board, P. W. , and Lynch, L. J. , " Fluid -
ized Bed Blanching of Green Peas for Processing," Food
Technology, 22, No. 6, pp 717-718 ( 1968 ).
4. Lazar, M. E. , Lund, D. B., and Dietrich, W. C. , "A New
Concept in Blanching ( IQB ), " Food Technology, 25,
No. 7, pp 684-686 ( 1971 ).
5. Huxsoll, C. C. , Dietrich, W. C., and Morgan, A.I. , Jr.,
"Comparison of Microwave with Steam or Water Blanching
of Corn-on-the-Cob. 1. Characteristics of Equipment
and Heat Penetration, " Food Technology, 24, No. 3, pp
290-292 ( 1970 ).
6. Dietrich, W. C. , Huxsoll, C. C., Wagner, J. R. , and
Guadagni, D. G. , "Comparison of Microwave with Steam
or Water Blanching of Corn-on-the-Cob. 2. Peroxidase
Inactivation and Flavor Retention, " Food Technology,
24, No. 3, pp 293-296 ( 1970 ).
7. Dietrich, W. C. , Huxsoll, C. C. , and Guadagni, D. G. ,
"Comparison of Microwave, Conventional and Combination
Blanching of Brussel Sprouts for Frozen Storage, " Food
Technology, 24, No. 5, pp 613-617 ( 1970 ).
8. Chen, S. C. , Cpllins, J. L. , McCarty, I. E., and Johnson,
M. R. , "Blanching of White Potatoes by Microwave Energy
Followed by Boiling Water, " Journal of Food Science, 36,
-49-
-------
No. 5, pp 742-745 ( 1971 ).
9. Anon. , "FWPCA Methods for Chemical Analysis of
Water and Wastes, " Analytical Quality Control Lab-
oratory, Division of Water Quality Research, Federal
Water Pollution Control Administration, Department
of the Interior, Cincinnati, Ohio ( 1967).
10. Anon. , Laboratory Manual for Food Canners and Proces
sors, The AVI Publishing Company, Westport, Connecti
cut ( 1968 ).
11. Anon., Official Methods of Analysis of the Association
of Official Analytical Chemists, Eleventh Edition,
Association of Official Analytical Chemists, Washington,
D. C. (1970).
12. Watt, B.K. , and Merrill, A. L. , Composition of Foods.
Agriculture Handbook No. 8, Agricultural Research
Service, U.S. Department of Agriculture, Washington,
D. C. (1963).
13. Orr, M. L. , Pantothenic Acid, Vitamin BA, . and Vitamin
B12 in Foods. Home Economics Research Report No. 36,
Agricultural Research Service, U. S. Department of
Agriculture, Washington, D. C. (1969).
14. Anon. , "Recommended Daily Dietary Allowances, "
Food and Nutrition News ,40, No. 2 (1968).
15. Anon. , The Almanac of the Canning, Freezing, Preser-
ving Industries, Edward E. Judge & Sons, Inc. , West-
minster, Maryland (1972).
16. Amerine, M.A., Pangborn, R.M. , and Roessler, E. B. ,
Principles of Sensory Evaluation of Food, Academic
Press, New York (1965).
17. Copley, M.J., and Van Arsdel, W. B. , Food Dehydration,
The AVI Publishing Company, Westport, Connecticut
(1964).
-50-
-------
SECTION IX
PUBLICATIONS AND PATENTS
Rails, J. W. , Maagdenberg, H. J. , Yacoub, N.L., and Mercer, W.A.,
"Reduced Waste Generation by Alternate Vegetable Blanching Systems"
U. S. Environmental Protection Agency Series EPA-R2 -72-018
(1972).
U.S. Patent Pending, Hot Gas Blanching
Process, Case No. WQO - 43 - 72 (G),
February 22, 1973.
-51-
-------
SECTION X
GLOSSARY
Acceptance -- (1) An experience or feature of experience, character-
ized by a positive ( approach in a pleasant ) attitude. (2) Actual utili-
zation ( purchase, eating ). May be measured by preferences or liking
for specific food item.
Analysis of Variance -- A method of determining the significance of
differences in a group of averages of experimental observations by
partitioning of the total sum of squares and degrees of freedom, and esti-
mation of the standard deviation of the population by two or more methods
and a comparison of these estimates.
Amortization -- (1) Gradual reduction, redemption, or liquidation of the
balance of an account according to a specified schedule of times and amounts.
(2) Provision for the extinguishment of a debt by means of a sinking fund.
Appearance -- The visual properties of a food, including size, shape,
color, and conformation.
BOD -- Abbreviation for biochemical oxygen demand. The quantity of
oxygen used in the biochemical oxidation of organic matter in a specified
time, at a specified temperature, and under specified conditions.
COD -- Abbreviation for chemical oxygen demand. A measure of the oxygen
consuming capacity of inorganic and organic matter present in water or
wastewater.
Blanching -- Heating a food to a temperature high enough to inactivate en-
zymes present and to remove undesirable occluded gases and contaminants .
Coding -- Assignment of symbols, usually letters and/or numbers, to test
samples so that they may be presented to a subject without identification.
Consumer -- An individual who obtains or uses a commodity.
-53-
-------
Cooling tower -- A vertical structure with internal baffles to break
up flowing water so that it is cooled by upward-flowing air and by
evaporation of water.
Enzyme -- A catalyst produced by living cells which is protein in
nature.
Flavor -- An attribute of foods, beverages, and seasonings resulting
from stimulation of the sense ends that are grouped together at the
entrance of the alimentary and respiratory tracts - especially odor and
taste.
Fixed charge -- A charge that cannot be escaped, shifted, or altered,
such as interest, rent, taxes and amortization.
Make-up water -- Water added to circulating water in a system to
replace water lost by evaporation, leakage, or blowdown.
Panel -- A group of people ( observers, subjects, judges ) comprising
a test population which has been specially selected or designated in
some manner.
Peroxidase -- A class of enzymes which catalyze the reaction of molec-
ular oxygen with a substrate to produce a peroxide, link in the altered
molecule.
Protein -- Any of the complex nitrogeneous compounds formed in living
organisms which consist of amino acids bound together by peptide link-
ages.
Quality -- The composite of the characteristics that differentiate among
individual units of the product and have significance in determining the
degree of acceptability of the unit by the user.
Ranking -- A procedure of arranging food products in order according
to some criterion and assigning consecutive integers (ranks) correspond
ing to the order.
Sample -- A specimen or aliquot presented for inspection.
-54-
-------
Score -- A value assigned to a specific response made to a test item.
Suspended Solids (SS) -- Solids that either float on the surface of, or
are in suspension in, water, wastewater or other liquids.
Taste -- One of the senses usually limited to four qualities: saline,
sweet, sour and bitter.
Vapor pressure -- The pressure exerted by a material in the gaseous
state when confined in a space of fixed volume.
-55-
-------
SECTION X
APPENDICES
Page
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Appendix G
Appendix H
Appendix I
Appendix J
Appendix K
Microwave Blanching Unit Specifications 58
Hot-Gas Blanching Unit Specifications 59
Steam and Hot-Water Blanching Unit 60
Specifications
Taste Panel Scoring Sheet 61
Headspace Gas Analysis Method 62
Short Duration Blanching Runs 65
Characteristics of Grab Samples from 73
Hot Water Blancher
USDA Scoring Sheets for Quality Grading 74
of Canned Vegetables
Vitamin Content in Raw, Blanched, and 81
Canned Vegetables
Mineral Content of Raw and Blanched 84
Vegetables
Cost Estimates for Commercial Scale 85
Blanching
-57-
-------
Appendix A
MICROWAVE BLANCHING UNIT SPECIFICATIONS
Length
Width
Microwave frequency
Microwave power (2-2. 5 kw
power packs)
Entrance and exit port size
Belt
Belt speed
Cavity material
Finish
Power requirements:
Conveyor only
Air heaters only
Each power pack
Air supply
o
Air temperature controllable to 250 -F
Water requirements (-each power pack)
Steam
20 ft
2 ft
2450 t 50 MHz
5 kw
4 in. high x 12 in. wide
1/4 in. mesh, coated
fiberglass
0-20' per min, reversible
Stainless steel
28 exterior; 4B
220V: 3-phase; 60 Hz
1 kVA
30 kVA
5 kVA
Adjustable 200-600 cfm
1. 5 gpm @ 20 psig/min
40 psi g
-58-
-------
Appendix B
HOT-GAS BLANCHING UNIT SPECIFICATIONS
Length:
Width:
Conveyor:
Conveyor width:
Conveyor drive:
Heater:
Blower:
Air Temperature:
Product Capacity:
16.5 ft
6.5 ft
Stainless steel belt in two
levels each with flights,
3 in. high and 12 in. apart
12 in.
Variable speed motor with
10 fold speed range
Natural gas fired burners
Rated at 12. 5, 000 Btu/hr
3800 standard cu ft/min
250 F Maximum
500 Ib/hr
-59-
-------
Appendix C
STEAM AND HOT-WATER BLANCHING UNIT SPECIFICATIONS
Length:
Width:
Belt Width:
Material of Construction:
•Bearings:
Conveyor ( chain )
Shaft diameter:
Drapes:
Drive:
Belt speed:
Steam coil test pressure:
8. 5 ft.
18.5 in.
15.25 in.
18 - 8 (304) stainless steel
Bronze brushed with grease
fittings
No. 40, extended pitch
1 in .
B-N standard type, 16 GA.
mesh 3/16 in. openings with
2. 5 in. high flights at 6 in.
spacing
4. 9 - 49 rpm, U. S. Varidrive
RT. angle, 0. 5 hp, 3 phase,
60 cycle
4-40 fpm
225 psig
-60-
-------
Appendix D
TASTE PANEL SCORING SHEET
Please taste and rank samples in order of flavor preference. Take
completed scoring sheets and used sample tray to cutting room.
CODE FLAVOR RANKING
1 = Best; 4 Worst
M
N
O
Date Tasters' Initials
-61-
-------
Appendix E HEADSPACE GAS ANALYSIS METHOD
Cans are opened under water, beneath a funnel connected to either a
50 or 100 ml burette to collect and read the volume of headspace gas.
The burette can be modified by a glass blower by cutting off stop cock
and placing it on top, above the zero mark. A small .side arm is made
to take the sampling septum ( Kontes silicone rubber stopper No. K77-
4200 ). The space between the stop cock and the zero mark, including
the side arm should be as small as practically possible ( measure the
volume ). Now, below the 50 ml graduation mark, put a side arm,
which will be connected to the leveling bulb by means of rubber tubing.
The large funnel is also connected to the burette through rubber tubing.
The procedure is as follows:
1. Clamp tubing.
2. Open burette at stop-cock and draw water into the burette through
funnel, with the help of vacuum.
3. When full, close stop cock and clamp tubing.
4. Remove clamp and fill leveling bulb and tubing with water, squeeze
tubing with fingers to make absolutely certain that no air bubbles
are trapped in it.
5. Place can to be sampled into the water and remove all visible air
droplets clinging to its surface.
6. Place can underneath the funnel and punch a hole in it with a church
key. Usually the can is put on its side and the hole punched so that
the gas will not escape immediately, but will do so when the can is
rotated under the funnel.
7. Once all of the gas in the can has been collected, adjust the liquid
level in the burette to that of the leveling bulb and read the volume
of gas ( add the volume above the zero mark ).
-62-
-------
Appendix E Cont'd
9. Raise the leveling bulb above the level of the gas in the burette;
this will give a slight positive pressure inside the burette. Insert
the syringe through the septum, pump it two or three times, and
withdraw the sample.
10. Inject into the chromatograph.
Standards
For N2 and 02, air is used and figure on a proportion of eight parts N2
to two parts 02.
For CO2 and H2, buy a mixture of 50:50 from Mathieson. Close off the
valve on the CO2 + H2 tank and apply vacuum. Close off vacuum and
open up tank valve, repeat this two or three times and then take the
sample through the septum.
Chromatographic conditions are as follows:
Column 1: Fourteen inches x 1/4" O.D. , Cu; Silica Gel 30/60 mesh.
Column 2: Transfer column, 20 ft x 1/8", Cu; This column connects
the outlet of column 1 to the inlet of column 3,
Column 3: 12 ft x 1/4" molecular sieve 5A, 30/60 mesh.
Oven temperature - This will vary according to the condition of the columns.
Start at around 100 C, and increase gradually, if analysis takes too long.
Detector temperature - 200 C
Injector temperature - 150 C
Carrier gas - He; It will be necessary to experiment with the flow rate
until the best rate according to conditions is found.
-63-
-------
Appendix E Cont'd
The first peak to show up is made up of all the gases except CO2,
which appears very shortly after that. Once the CO2 peak has com-
pletely gone through, as indicated by the recording pen coming back
to the base line, switch polarity and H2, O2 and N2 will appear in that
order.
Using He as a carrier, a plot of concentration vs peak height should
give a straight line for each of CO2, N2 and O2. This is not usually
true of H2, which as its concentration relative to He increases will
give a peak with an inverted tip. Usually H2 is determined by differ-
ence. Add up the percentage of the three remaining gases and compute
the difference.
It seems that what has been called O2 in the headspace gas for several
years is probably argon. The conditions used cannot separate argon
and oxygen. To detect O2, it would be necessary to use argon as a
carrier gas ( in which case a peak shows up ) it would indicate the
presence of oxygen, as argon would not respond.
-64-
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Appendix F
SHORT DURATION BLANCHING RUNS
Green Asparagus
Run
No.
Raw-1971
ASP -7
ASP -8
ASP -9
ASP-10
ASP- 11
ASP-12
ASP-13
ASP -14
ASP-15
ASP- 16
ASP-17
ASP-32
Blanch-
ing Unit
_
5 kw
Microwave
it
ti
ii
it
4 kw
Microwave
ii
3 kw
Microwave
ii
it
ii
5 kw
Microwave
Feed
Rate,
Lb/Hr
_
49
240
300
160
105
100
225
225
66
86
113
257
+
Residence
Time, Sec
_
673
84
84
160
281
398
130
130
281
206
160
84
Temp,
°F
_
183
183
151
151
151
210
210
210
210
210
210
144
Peroxidase
Inactivation
Slope
0. 192
Over blanched
0. 193
0.210
0. 160
0.033
0. 010
0. 285*
0.300*
0. 135
0. 175
0. 175
0.233
Steam Injection
ASP-33
ASP -34
ASP -35
ASP-1
ASP-2
ASP-18
ASP-19
ASP-20
ASP -3
ASP -5
ASP -21
ti
n
ii
Steam
it
it
ti
u
Hot Water
n
n
168
168
N.R.
323
331
400
267
268
120
172
278
160
104
130
135
100
79
100
134
227
147
90
144
144
144
212
212
200
200
200
180
190
180
0.055
0. 165
0. 080
Over blanched
0.008
0. 005
0.003
0.00
0.007
0.004
0.04
-65-
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Appendix F
Cont'd
Green Asparagus Cont'd
Run
No.
ASP-22
ASP -23
ASP-27
Raw-1972
ASPS-1
ASPS -2
ASPS -3
ASPS -4
ASPS -5
ASPS -6
Feed
Blanch- Rate,
ing Unit Lb/Hr
" 288
" 343
267
_ _
Hot-Gas + 400
Steam Injection
" 600
" 600
" 450
11 500
11 430
Residence
Time, Sec
66
52
90
_
165
106
105
145
131
150
Temp,
°F
180
180
190
_
240
260
200
240
250
250
Peroxidase
Inactivation
Slope
0-04
0.10
0.007
0.4
0.0002
0.0002
0.0002
0. 0002
0. 0002
0.0002
N.R. Not Recorded
* Higher values due to lower moisture content of sample.
-66-
-------
Appendix F
Cont'd
Green Peas
Run
No.
Raw
P-14
P-16
P-15
P-7
P-8
P-9
P-10
P-ll
P-12
P-l
P-2
P-4
P-5
Feed
Blanch- Rate,
ing Unit Lb/Hr
5 kw 138
Microwave +
Steam Injection
11 139
0 kw 167
Hot-Gas 133
Hot -Gas + 300
Steam Injection
11 300
" 343
" 369
11 1200
Steam N. R.
11 150
Hot-Water 274
Hot-Water 192
Residence
Time, Sec
160
130
160
720
120
120
120
120
120
62
90
62
90
Temp
o
F
150
150
150
225
220
205
226
237
250
180
180
180
185
Peroxidase
Inactivation
Slope
1. 75
0. 58
0.51
1.80
0. 01
0.03
0. 08
0. 18
Over blanched
0. 14
0.85
0.02
0.93
0. 07
-67-
-------
Appendix F
Cont'd
Green Beans
Run
No.
Raw
3 Sieve
BN-6
BN-7
BN-8
BN-9
BN-10
BN-1
BN-2
BN-3
BN-4
BN-5
BN-11
BN-12
Feed
Blanch- Rate, Residence
ing Unit L.b/Hr Time, Sec
— —
Size
5 kw 85
3 Sieve Size
Microwave +
Steam Injection
" 111
3 Sieve Size
" 108
2 Sieve Size
" 129
2 Sieve Size
" 120
1 Sieve Size
Hot-Gas + 170
Steam Injection 3 Sieve
" 200
3 Sieve Size
'• 109
3 Sieve Size
" 150
3 Sieve Size
" 200
3 Sieve Size
" 203
2 Sieve Size
" 300
..
281
206
206
180
130
183
183
303
233
183
136
103
Temp,
°F
—
146
130
130
112
98
220
250
250
250
250
250
250
Peroxidase
Inactivation
Slope
Optical
Density
Greater
than 2
0.41
0.44
0.42
0.53
0.81
1.0
0.19
0.03
0.03
0.06
0.12
0.38
1 Sieve Size
-68-
-------
Appendix F
Cont'd
Green Beans
Run
No.
BN-13
BN-14
BN-15
BN-16
BN-17
BN-18
BN-19
BN-20
BN-21
BN-22
BN-23
BN-24
Feed
Blanch- Rate, Residence
ing Unit Lb/Hr Time, Sec
Steam 180
3 Sieve Size
11 172
3 Sieve Size
11 172
3 Sieve Size
" 124
2 Sieve Size
Steam 138
1 Sieve Size
11 129
1 Sieve Size
Hot-Water 146
3 Sieve Size
it 154
3 Sieve Size
" 142
2 Sieve Size
" 120
2 Sieve Size
112
1 Sieve Size
100
1 Sieve Size
217
217
90
217
90
217
291
182
182
227
182
227
Peroxidase
Temp Inactivation
°F Slope
180 0.25
190 0. 10
190 0. 12
190 0. 18
190 0. 20
190 0. 16
190 0. 04
" 0. 05
" 0. 08
" 0. 09
11 0. 08
" 0.11
-69-
-------
APPENDIX F
Cont'd
Corn-on-Cob
Run
No.
Raw
CN-4
Blanch-
ing Unit
..
5 kw
Feed
Rate,
Lb/Hr
«•
Microwave + 82
Residence
Time, Sec
—
422
Temp,
°F
—
142
Peroxidase
Inactivation
Slope
0. 110
O ve r blanched
Steam Injection
CN-5
CN-6
CN-1
ti
K
Hot-Gas +
100
194
400
224
133
240
140
140
255
0. 008
0.008
0.028
Steam Injection
CN-2
CN-3
CN-7
CN-8
CN-9
CN-11
ti
H
Steam
H
M
Hot -Water
320
202
201
172
266
187
330
390
561
658
435
373
255
260
195
195
195
190
0. 034
0.005
O ve r blanched
Over blanched
0.020
0.04
Red Beets
Run
No.
Raw
BT-4
BT-5
BT-6
BT-1
Blanch-
ing Unit
5 kw
Microwave +
Feed
Rate,
Lb/Hr
85
Steam Injection
239
M
Hot -Gas +
305
69
Residence
Time, Sec
224
93
53
1100
Temp,
°F
.
130
130
130
258
Peroxidase
Inactivation
Slope
1.140
Over blanched
0. 145
0.210
Over blanched
Steam Injection
-70-
-------
APPENDIX F Cont'd
Red Beets Cont'd
Run
No.
BT-2
BT-3
BT-9
^Earlier
Pumpkin
Run
No.
Raw
PM-1
Blanch-
ing Unit
ti
ii
Steam
Hot -Water*
Feed
Rate,
Lb/Hr
131
170
155
-
runs with fresh market
Pieces
Blanch-
ing Unit
5 kw
Microwave +
Feed
Rate,
Lb/Hr
50
Residence
Time, Sec
625
390
330
480
beets
Residence
Time, Sec
680
Temp,
°F
258
250
198
200
Temp.
°F
80
Peroxidase
Inactivation
Slope
0.073
0. 100
0. 04
0.04
Peroxidase
Inactivation
Slope
7.43
0.64
Steam Injection
PM-2
PM-3
PM-10
M
it
Hot -Gas +
50
150
200
680
390
330
Steam Injection
PM-11
PM-12
PM-4
PM-5
PM-6
M
140
Steam Injection 65
Steam
it
11
PM-7 Hot -Water
PM-8.
PMr9
M
n
150
224
256
400
200
200
390
1100
766
560
340
227
510
510
140
140
235-
250
250-
265
250-
265
193
194
196
190
192
209
0. 13
0. 10
1.8
0. 10
0.33
0.002
0.047
0.11
7.0
1.7
0.033
-71-
-------
APPENDIX F
Cont'd
Spinach
Run Blanch -
No. ing Unit
Feed
Rate,
Lb/Hr
Peroxidase
Residence Temp, Inactivation
Time, Sec °F Slope
Raw
SP-1A 5 kw 17
Microwave +
Steam Injection
SP-1B " 16
SP-2A Hot-Gas + N. R.
Steam Injection
SP-2B " N. R.
224
133
330
183
140
140 Overblanched
250 Dried
250
O ve r blan che d
-72-
-------
APPENDIX G
CHARACTERISTICS OF GRAB SAMPLES FROM HOT-WATER
BLANCHER
Commodity
Asparagus
Green Peas
Green Beans
Beets
Pumpkin
Spinach
Sampling Time,
Min
15
30
45
60
15
30
45
15
30
45
60
15
30
45
60
15
30
45
60
15
30
COD,
mg/1
51
72
100
130
1,760
3,900
4,550
150
200
370
490
160
250
400
620
220
450
780
910
190
260
ss,
mg/1
1
0
0
0
113
176
180
1
4
3
10
5
15
15
16
22
29
PH
7.7
7.7
8. 1
7.4
4.6
4.6
4.7
7.5
7.3
7.1
6.9
7.4
7.2
7.0
7.0
6.4
6.4
-73-
-------
APPENDIX H
USDA SCORING SHEETS FOR QUALITY GRADING
OF CANNED VEGETABLES
-74-
-------
SHtET / OF / SHEETS
rom FV-M*«
\JM. DEPARTMENT Of AGRICULTURE
CONMJMKR AND MANKKTIPM ••MVICB
SCORE SHEET FOR
CANNED ASPARAGUS
(EFFECTIVE MAY 7. 1963)
CONT. NO.
r.o.NO.
CERT. FORM
mr.no.
CERT. NO.
HAM AND ADDRESS Of APPLICANT
NO. .SIZE AN» KIND Of CONTAINEII
LABEL
CONTAINER MARK
OR
IDENTIFICATION
NET VEI6HT (OUNCES)
VACUUM (INCHES)
DRAINED WEICHT (OUNCES)
TYPE
STVLE
CUTStfttf,
SIZE (SPEARS. TIPS. POINTS)
COUNT (SPEARS. TIPS. POINTS)
7^
PACTORS
I. IIQDTJI
II. COLOB
III. DBPBCT8
IT. CHillCIU
1DTM. 300RE
SCORE POINTS
..
*°
(C)
(SStd) 0-<
(A) 17-10
(C) 14-11
(SStd) 0-U*
1C) ll-«4*
(SStd)
y •?
FLAVOR (A, C* OR ISM*)
100
It
-£Z-
8*
18
/7
— s
o
~o
JSTK
-v
CHAM6C ON CERTIFICATE
PBINCIPAL REASONS ron DIM AD INS PRODUCT
OFFICIAL INSPECT01
FEE
IXPtNSEI
DATE-"
lM Ml*.
-------
FV-BS4* (7-IS-St)
SHEET OF SMB«T»
U. «. BBPAJCTMBHT Of AOmCULTUMB
CONSUMER AND MARKET** SERVICE
SOME SHEET POt
CANNED GREEN AND WAX BEANS
(Effective Jwly 23, 1961)
CONT. NO.
P.O. NO.
R«F. NO.
CERT. FORM
CERT. NO.
NAME AM* AMREM OF APPLICANT .
I1S£> Si'tft Sf**fT'
Bfr«,lfi fi, /,/„», 4 r^'*
NO.» MSK AND KIND OF CONTAINKH
-------
SHEET/ or y SHEETS
ronu FV-364 -18
(6-I4-5T) •
U. S. DEPAITTMCNT OF AOmCULTUR*
AGRICULTURAL MAKKKTINO MtMVICK
SCORE SHEET FOR
CANNED WHOLE KERNEL (WHOLE GRAIN) CORN
(EFFECTIVE JULY 30, 1952)
CONT. NO.
P.O. NO.
CUT. FORM
•If .NO.
CENT. NO.
NAM AND AODRtt* Of APPLICANT
NO..HJE AMD KIND Of CONTAIN*
* Linltiif rilo.
i F«rtt»l limitii| r«l«
-------
SHEET/ OF / SHEETS
r«NI FVO44.10 u. S. DEPARTMENT Of AGRICULTURE
l*tM!rl' AGRICULTURAL MARKETING SERVICE
SCORE SHEET FOR
CANNED BEETS
(EFFECTIVE FEBRUARY *, 1955)
tma. INK
'•*•"*'
mr .NO.
CCMT. FOB*
CERT. NO.
NAME AMD
r?-Cl
A»OMM Of AMLICAMT
7ov.«c^ ^"AWWCH
i'«Uy UL.^
„ A^,.
•0. .(Ill AM HMD Or CONTAINED
LABEL
rtl«. x P»rti«l
»«tl.i4ii
-------
• &NW PV-M4-SS (10-e-M)
SHEET / Of
• U.S. DEPARTMENT OF AGRICULTURE
CONSUMER AND MARKETING SERVICE
SCORE SHEET FOR
CANNED PUMPKIN and CANNED SQUASH
(EFFECTIVE MARCH 9, 1956)
NO. .SIZE AM RIND OF CONTAINER
CONT. NO.
P.O. NO. CERT. FORM
• IF. NO. CERT. NO.
NAME AND ADDRESS OF APPLICANT
"1 3?£&kJ£l'£ y ^sJi.//o4.*>f*t
/
LAI EL
u/c.
CONTAINER MM
OR
IDENTIFICATI
RK CANS
°" CASES
SAMPLE NO.
NET •EI6HT (OUNCES)
VACUUM (INCHES)
. FACTORS
COLOR
NO
1
CONSISTENCY
FINISH
DBP1CTS
TOTAL SCORE
SCORE POINTS
20
SO
20
so
100
(Al 18-20
(C) 14-17"
(SStdl 0-lS*
(Al 26-10
(Cl 21-24*
(SStdl 0-20*
(A) 17-20
(C) 14-16
(BStdl 0-11*
(Al 26-10
(C) 21-24*
(SStdl 0-20*
NORMAL aAVOR
MAM
CHARGE ON CERTIFICATE
• II
LAMMES
TUlfeL
7* *AB
ter.*s
_ L
I x
/ ?
/ 0
Lltytot.
n
zt
7%
AJ
SSTJ>
ftt*
7/"
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l&
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L
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n
£t
18
rJ
.ssn>
REMARKS
$u&sr#tJb**l
Cfr*£ ±> 9*»
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**«*
3
lb*3>
'/_..
20
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17
71 'ttft
<*,'«**•
¥
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SH
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1
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.
OFF 1C IAL
IMlFtCTO*
*&&
'
^
AVERAGE
APPENDIX
ffi
O
o
3
CL
DATE . /
-2A2/72-
* Linltlif RuU.
-------
FORM rv-3B*-1M
(S-90-70)'
U. S. DEPARTMENT OF AGRICULTURE
CONSUMER AND MARKETING SERVICE
DEFECT TALLY SHEET FOR CANNED SPINACH
(EFFECTIVE MARCH 30. 1970)
NAME AND ADDRESS OF APPLICANT
GRADE
DATE
'. I * t. F
1 WHOLE LE AT
j '] CUT LEAF OR SL. f O
.X -"O
NO., SIZE, AND KINO OP CONTAINER
CUMULATIVI TOTAL (ALL CLASSES)
STBN MATERIAL 29% (A) JO* <•)
-------
Apoendix I Vitamin Content of Raw, Blanched, and Canned Vegetables,
Values in mg/100 g wet weight ( Standard Deviation )
Blanched Samples
Canned and Stored (Six Months) Samples
Commodity
Asparagus
oo
»••
i
Green Peas
Vitamin Raw Microwave Hot -Gas
B, .22
( -0)
B2 .218
.230
( . 008)
C 18.7
19. n
18. 3
19.2
18. 1
( -5)
Niacin 1.56
1.58
1.52
(.03)
B, . 07
(-0)
Bz . 168
. 173
( . 004)
B6 *
*
. 162
.202
.212
(.03)
13.4
13.4
14.2
14. 9
14. 1
( -6)
1. 80
1.85
1.80
(.03)
. 10
(.0)
. 177
. 170
{ . 005)
.24
. 178
. 177
( .001)
. 183
. 189
( . 004)
11. 1
10.4
10.4
10.6
( • 4)
.70
.75
.71
.76
( .03)
. 14
( .0)
. 176
. 170
.004
.27
Steam
*
.226
. 190
. 172
(.027)
22. 5
22. 0
22. 2
21.4
( -5)
1.40
1. 53
1.40
(.08)
.07
( -0)
. 129
. 125
. 003
. 32
Hot-Water
*
. 198
.208
( . 007)
16.7
19.8
16.7
17. 1
(1.5)
1.60
1.70
1.60
1.68
( .05)
.06
(.0)
. 157
. 143
. 010
.22
Microwave Hot-Gas
.049
.057
(.01)
.104
.087
(.012)
3.79
3.79
(.0 )
.70
.60
.62
.65
( .04)
. 099 . 110
. 100 . 108
(.001) (.001)
.075 .083
.075 .081
(.0) (.001)
.109 .154
. 1 54 . \ 54
. 142 140
( . 025) ( . 008)
Steam Hot-Water
.059
.043
(.011)
. 092
.087
( . 004)
3.69
3. 55
( • 10)
.80
.76
.80
.73
( -03)
. 102
. 103
( .001)
.064
.070
(.005)
.096
. 1'?
. 096
(.015)
.057
. 056
(.001)
. 110
. 104
{ . 004)
3. 55
3.69
( • 10)
.71
.75
.70
.70
( -02)
.089
.089
( -0)
.065
.072
(.005)
.098
114
. 109
( . 008)
-------
Appendix I Cont'd
Commodity
Green Beans
B,
B,
8
i
Niacih
Corn
B,
Vitamin Content of Raw, Blanched, and Canned Vegetables,
Values in mg/100 g wet weight ( Standard Deviation )
Blanched Samples
Canned and Stored (Six Months) Samples
Raw
#
. 12
. 12
.14
. 13
(.01)
.051
.053
.064
( . 007)
.43
.55
.48
.50
(.06)
#
. 120
.109
( .008)
. 18
Microwave
#
.14
. 12
.14
(.01)
.077
.064
.046
(.016)
.59
.65
.70
(.06)
*
. 102
. 115
( . 009)
.23
Hot -Gas
*
. 12
.12
. 12
(.00)
.038
.036
.036
.039
( . 002)
.80
.79
.60
(.11)
#
.112
.120
.006
.16
Steam
*
. 12
. 12
. 12
(.00)
.069
.055
.046
.041
(.012)
.70
.55
.52
.47
(.10)
*
. 106
. 105
(.001)
. 19
Hot -Water
#
. 11
.12
.12
(.01)
.077
.062
.050
.040
(.016)
.65
.61
.51
.50
(.07)
#
.119
.107
( . 008)
. 19
Microwave
.290
.280
( . 007)
.055
.053
(.001)
.049
.051
.053
( . 002)
.35
.36
.38
.33
(.02)
.025
.024
(.001)
.078
.080
( . 001)
.064
.082
.965.
(.008)
Hot-Gas
.386
.411
(.02)
.069
.062
(.005)
.049
.051
.063
( . 008)
.43
.36
.38
.39
.32
(.04)
.026
.025
{ .001)
.077
.082
( . 004)
.082
.078
.071
(.006)
Steam
.290
.300
(.007)
.058
.061
(.002)
.046
.054
.044
( . 005)
.40
.35
.35
.33
.33
(.03)
.025
.026
(.001)
.079
.074
( . 004)
.079
.061
. 076
(.003)
Hot -Water
.295
.290
( . 004)
.053
.058
(.004)
.063
.050
.064
( . 008)
.35
.33
.33
.30
.31
(.02)
.022
.021
(.001)
.071
.070
v (.001)
v ;6«
.076
( . 005)
-------
Appendix I Cont'd
Vitamin Content of Raw, Blanched, and Canned Vegetables,
Values in mg/100 g wet weight ( Standard Deviation )
Blanched Samples
Commodity
Corn
Beets
i
oo
Pumpkin
Spinach
Vitamin
Niacin
B2
C
Niacin
A
Niacin
A
B2
C
Raw Microwave
1.42
1.35
1.50
1.36
(.07)
.048
. 074
(.013)
6.9
.250
.231
(.013)
5.78
(.0)
.44
. 53
. 52
.47
(.04)
2. 30
. 065
.079
(.01)
#
2.25
2.25
2. 18
(.04)
.049
.059
(.007)
6.8
.213
. 213
(.00)
5. 05
(.0)
. 38
. 34
.42
. 37
( .03)
4.02
. 156
. 133
(.015)
*
Hot-Gas Steam Hot-Water
2.20
2.00
2. 12
1.93
(• 12)
.062
.074
(.008)
7.5
.263
.256
( .005)
4. 06
(.0)
.66
. 57
. 53
. 53
(.06)
4.21
. 130
. 138
(. 006)
*
2.25
2. 13
2.22
2. 13
(.06)
.035
.054
(.013)
5.6
. 200
. 194
( . 004)
7.91
(.0)
. 32
. 25
.24
. 25
( .04)
3.63
. 094
. 101
(.005)
*
1.97
1.70
2.00
1.98
(.14)
.036
.046
(.007)
7.9
.200
.200
(.0)
4.66
( .0)
. 30
.31
.33
.35
(.02)
3.74
.067
.078
( . 008)
*
Canned and Stored (Six Months) Samples
Microwave Hot-Gas Steam Hot-Water
.94
1.19
1. 10
(.13)
.015
.016
(.001)
4. 1
.075
.078
.088
.075
.006)
3.74
( .0)
.37
40
.38
.47
(.05)
1.Z8
1.87
( .14)
. 107
. 109
(.001)
1.00
1.07
1.22
1.20
(.11)
.014
.011
(.002)
5.0
.093
.094
.092
.083
.005)
3.09
(.0)
.40
.45
.42
.49
( .04)
1.94
2.57
(.14)
.095
.096
(.001)
1. 04
1.00
1.03
1. 19
(.09)
4. 1
. 118
. 102
. 110
. 109
( . 008)
2.98
( .0)
.28
.33
. 32
.39
(.05)
2.90
3.62
(.11)
. 07$
. 084
( . 004)
.90
1.00
.94
1.00
(.05)
.015 .023
. 013 . 022
(.001) ( .001)
4. 8
. 093
. 088
. 092
. 083
(.005)
5.22
(.0)
.23
. 29
.27
-. 32
( ". 04)
4. 06
4.87
( • 13)
. 088
.090
(.001)
* Sample Lost
-------
Corn
Beets
Pumpkin
Spinach
Ca
Mg
P
Ca
Mg
P
Appendix J Mineral Content of Raw and Blanched Vegetables,
Values in mg/100 g wet weight ( Standard Deviation )
Blanched Samples
Commodity
Asparagus
Peas
Beans
Mineral
Ca
Mg
P
Ca
Mg
P
Fe
Ca
Mg
P
Raw
20.9,21.4
15.8, 15.6
68.0,66.0
*
*
*
*
40.0,40.0
28.0,26. 0
36.0,36.0
(.4)
M)
(1.4)
(.0)
(1.4)
(.0)
87.0,79.0 (5.7)
21,6,23.8 (1.6)
9.9,8.5(1.0)
7. 1,6.3(.6)
11.7, 11.4 (.2)
63.5,66.4 (2. 1)
67.3,59.8 (5.3)
17.2,22.7 (3.9)
Microwave
22. 1,22. 1 (.0)
15.4, 15.6 (. 1)
77.0,77.0 (.0)
14. 3, 14. 0(.2)
28.3,28.6 (.2)
106, 102 (3)
1.00, 1.06 (.04)
46.4,45.2 (. 8)
28.2, 30. 4 (1.6)
40.0,40. 0 (. 0)
92.5,90.0(1.8)
25.6,26.4 (.6)
11. 3,6.3 (3. 5)
13. 5, 12. 3 (.8)
22.7,20.2 (1.8)
84.0,88.0(2.8)
91. 5,87. 3 (2.8)
54.2,46.2 (5.7)
Hot-Gas
19.2, 19.4 (. 1)
15.2, 15. 2 (.0)
62.0,61. 0 (.7)
14.2, 14. 6 (. 3)
28.4,29.8 (1.0)
114, 114 (.0)
1.05, 1.07 (. 01)
51.2, 52.8 (1. 1)
33.0,33.2 (. 1)
48. 5,47. 5 (.7)
82.0,75.0(4.9)
28. 8,24.4 (3. 1)
13. 5, 13. 5 (. 0)
10.9, 10.9 (. 0)
14.2, 13.6 (.4)
68. 0, 68. O(.O)
65.5,64.5 (.7)
42.7,42.2 (.4)
jteam
21.9,22. 1 (. 1)
14.4, 14.4 (. 0)
70.0,70.0 (. 0)
13.0, 13.0 (.0)
27.2,28.0 (.6)
102, 100(1)
.97, 1.00 (.02)
40. 0,38.4 (1. 1)
26. 6,26.4 (. 1)
36.4,35.6 (.6)
95.0,85.0 (7. 1)
Hot-Water
19.8,20. 5 (.5)
16.3, 16.4 (. 1)
69.0,70.0 (.7)
14.2, 14. 1 (. 1)
28.0,28.6 (.4)
96, 100(3)
1. 04, 1. 03 (.01)
40.4,40.8 (. 3)
26.6,27.6 (. 1)
39.6,37.2 (1.7)
22.0,24.8(2.0) 22.0,20.4(1.2)
10.9, 10.5 (. 3)
9.5,9.7 (. 1)
15. 2, 13. 2 (1.4)
63.0,67.0(2.8)
67. 5,63. 5 (2.8)
42.2,42.7 (.4)
10.7,7. 7 (2. 1)
8. 1,6. 3 (1.3)
8.2, 11.2 (2. 1)
45.5,55.5 (7. 1)
49.5,48. 5 (.7)
33.7,29.2 (3.2)
* Sample Lost
-------
Aooendix K
COST ESTIMATES FOR COMMERCIAL SCALE BLANCHING
First Cost - 5 ton/hr Microwave blancher = $425, 000
Annual Fixed Costs
Amortization = FC x erf (7%, 5yrs = .24389) = $103,655.
Space rent = 12, 000.
Taxes = 5,310.
Insurance = 850.
Maintenance (2.5% of FC/yr) = 10, 625.
Total = $132,440."
Hourly fixed cost (1800 hr yr ) = 73. 58
Hourly Operating Costs
Electric power ($.0125/kwh) (210 kw) = 2.63
Steam consumption ($1. 00/1000 Ib ) = .80
Water consumption ($. 10/100 cu ft ) = .05
Klystron replacement (7 tubes @$9200, 6000
hr life) = 10.73
Waste disposal ($.05 /Ib for BOD&SS) = .17
Labor (1 worker @ $4.40/hr ) = 4.40
Total = 18.78
Total Hourly Cost
Fixed Cost= 73. 58
Operating Cost= 18. 78
Total = 92.36
Cost/lb vegetable blanched (10, 000 Ib/hr) = . 00924
Cost/ton vegetable blanched = 18.47
-85-
-------
Appendix K Cont'd
First Cost - 5 ton/hr Hot-gas blancher = $50, 000. 00
Annual Fixed Costs
Amortization FC x erf (7%, 5 yrs = .24389) = $ 12,195.
Space rent = 6, 000.
Taxes = 625.
Insurance = 100.
Maintenance (1. 5% of FC/yr) = 750.
Total = $ 19,670.
Hourly fixed cost (1800 hr yr) = 10. 93
Hourly Operating Costs
Electric power ( $. 035/kw ) = .61
Steam consumption ( $ 1. 00/1000 Ib ) = .10
Water consumption ( $ . 10/100 cu ft ) = .00
Gas consumption ( $. 076/therm ) = .89
Waste disposal ( $ . 05/lb for BOD & SS ) = .00
Labor ( 1 worker @ $ 4. 40/hr ) = 4. 40
Total = $ 6. 00
Total Hourly Cost
Fixed Cost = 10. 93
Operating Cost = 6. 00
Total = 16.93
Cost/lb vegetable blanched ( 10, 000 Ib/hr ) = .00169
Cost/ton vegetable blanched = $ 3. 39
-86-
-------
Appendex K Cont'd
First Cost 5 ton/hr Steam blancher = $15.000.00
Annual Fixed Costs
Amortization FC x erf (7%, 5 yrs = . 24389)
Space rent
Taxes
Insurance
Maintenance ( 1% of FC/yr )
Total
Hourly fixed cost (1800 hr yr)
= $ 3,660.
6, 000.
190.
30.
150.
= $ 10,030.
5.57
Hourly Operating Costs
Electric power { $ . 035/kw )
Steam consumption ( $1. 00/1000 Ib )
Water consumption ( $ . 10/100 cu ft )
Waste disposal ( $ 0. 05/Ib for BOD & SS )
Labor ( 1 Half-time worker @ $4. 40/hr)
. 13
2.41
.00
.76
2.20
Total = $
5.50
Total Hourly Cost
Fixed Cost
Operating Cost
Total
Cost/lb vegetable blanched ( 10,000 Ib/hr )
Cost/ton vegetable blanched
5.57
5.50
11.07
.00111
2.21
-87-
-------
Appendix K Cont'd
First Cost 5 ton/hr Hot-water blancher = $20,000.
Annual Fixed Costs
Amortization = FC x erf (7%, 5 yrs = .24389) = $ 4,880.
Space rent = 6, 000.
Taxes = 250.
Insurance = 40.
Maintenance ( 1% of FC/yr ) = 200.
Total = $ 11,370.
Hourly fixed cost { 1800 hr yr ) = 6. 32
Hourly Operating Costs
Electric power ($. 035/kw) .13
Steam consumption ($1. 00/1000 Ib) 1.92
Water consumption ( $ . 10/100 cu ft ) . 08
Waste disposal ( $ 0. 05/lb for BOD & SS ) 1. 17
Labor ( 1 Half-time worker @ $4. 40/hr ) 2.20
Total = $ 5.50
Total Hourly Cost
Fixed Cost = 6.32
Operating Cost = 5. 50
Total = 11.82
Cost/lb vegetable blanched { 10,000 Ib/hr ) = .00113
Cost/ton vegetable blanched = 2. 36
-88-
-------
SELECTED WATER
RESOURCES ABSTRACTS
INPUT TRANSACTION FORM
1. Report No.
2.
3. Accession No.
W
4. Title LOW Water Volume Enzyme
Deactivation of Vegetables
Before
7. Author(s)
Rails, Jack W. and Mercer, Walter A.
5. Report Date 3-15-73
6.
8. Performing Organization
Re port No. D-2615
9. Organization
Research Foundation
National Canners Association
1950 Sixth Street
,, 0 Berkeley.. California 94710
/-. SponsoringUrgan.-zafjon
U. S. Enviornmental Protection Agency
15. Supplementary Notes
Environmental Protection Agency report
number, EPA-R2-73-198, May 1973.
10. Project No.
5653
//. Contract I Grant No.
12060 PAV
1J. Type of Report and
Period Covered
Final
5-1-71 to 11-30-72
16. Abstract Four pilot-plant units were operated with asparagus, peas, corn, beans,
be.ets, pumpkin and spinach to establish the potential for new blanching systems
with low wastewater generation. The systems investigated were microwave, hot-gas,
steam, and hot-water. Single runs of about one hour duration were made for each
commodity with each blanching system. Wastewater volume was measured and
samples were analyzed for COD, SS, and pH. The most striking result obtained was
the small volume of steam condensate formed during hot-gas blanching. Canned
samples of vegetable material from each blancher were prepared for quality eval-
uation after storage. Taste panels showed no significant flavor preference for sam-
ples from any individual blanching system. The system used had no significant
effect on the vitamin and mineral retention of blanched or canned samples. The
oxygen content of canned samples was lowest for hot-gas blanching compared to the
other three systems. Estimates of the cost of blanching using commercial-scale
units gave (dollars/ton blanched): microwave, 18.47; hot-gas, 3.39; steam, 2.21;
and hot-water, 2. 36.
17a. Descriptors
Blanching, vegetables, food processing, wastewater, reduced waste
generation, microwave blanching, hot-gas blanching, steam blanching, hot-water
blanching*
17'b. Identifiers
Canning ( food processing }
1 7c. CO WRR Field & Group Q 5D
18. Availability
General
Abstractor
Jack W.
19.
20.
Rails
Security Class.
(Report)
Security Class.
(P'ge)
\ Insti
21. No. of
Pages 88
22. Price
Send To:
WATER RESOURCES SCII-NTIFlC INFORMATION CE!" T ET.
U.S. DEPARTMENT OF THE INTERIOR
WASHINGTON. D C 20240
tution National Canners
Association
WRSIC 102 (REV JUNE 1971)
MJ.S. GOVERNMENT PRINTING OFFI
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