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This is to certify that the
thesis entitled
AN INVESTIGATION OF AN OXYGEN SCAVENGER
PACKAGING FILM AS AN INNER PACKAGE ANTI-
OXIDANT DEVICE

presented by
RICHARD SCOTT ERNSBERGER, JR.

has been accepted towards fulfillment
of the requirements for

M. S . degree in Packaging

fiZ/fl/gé/r/

Wayne H. Clifford, Ph.D.

Major professor

Date 3! 13.176

0'? 639

 

 

 

 

 

ABSTRACT

AN INVESTIGATION or AN OXYGEN SCAVENGER
PACKAGING FILM As AN INNER PACKAGE
ANTIOXIDANT DEVICE
By

Richard Scott Ernsberger, Jr.

This investigation was conducted to support the use of an oxygen
scavenger film as an inner package antioxidant device rather than the
complete primary package. Samples of American Can's Maraflex 7—F
oxygen scavenger film with different ratios of headspace volume to film
surface.area were examined for their oxygen consumption activity. It
was found that by increasing the surface area of the material while
maintaining a constant headspace volume, the half—life period for oxygen
consumption would decrease. Specifically, for the three primary runs
with volume to surface area ratios of 18.6:1, 8.3:1, and 2:1, the
average half—life periods were 342.27, 108.47, and 47.56 hours respec—
tively. The average oxygen consumption rate or material specific
activity was established at 5.46 x 10’3 grams of 02/cm2/atms/hr.

Additionally, it was found that some inhibition of material activity
occurs through its use resulting in a regression of activity through
reuse. The cause or causes producing this phenomenon were not deter—

mined.

AN INVESTIGATION OF AN OXYGEN SCAVENGER
PACKAGING FILM As AN INNER PACKAGE
ANTIOXIDANT DEVICE
by

Richard Scott Ernsberger, Jr.

A THESIS
Submitted to
Michigan State University
in partial fulfillment of the requirement
for the degree of:
MASTER OF SCIENCE
SCHOOL OF PACKAGING

1976

ACKNOWLEDGMENTS

I offer my appreciation to those individuals of Technology Inc.,
who provided technical assistance where my familiarity with various
laboratory equipment and assorted analytical techniques necessitated
additional guidance. Specific gratitude is offered to Dr. Clayton
S. Huber, without who‘s personal interest and academic support, the
subject of this investigation would lack much substance. Additional
recognition must be given to Alfred B. Wagner, Jr., who's professional,
academic, and personal support has contributed an invaluable element
not to mention an ever stimulating environment circumferencing my
investigations.

Gratitude goes to Dr. Wayne Clifford, my major professor, for his
continuing patience, personal support, and academic guidance which he
has provided for me throughout my entire program.

Special appreciation is rendered to my parents, Mr. and Mrs. R. S.
Ernsberger, Sr., and to my in-laws, Dr. and Mrs. Elmer Anttonen, for
their continuing support and encouragement. To Doug Novakoski without
who's zealous interest in Packaging and philanthropic attitude and
personality, I would not be in Packaging today.

Finally, to my wife Alice, who's undying resourcefulness, inde—
fatiguable patience, and convivial personality has uniquely provided a
buffer against periodic discouragement and a stimulative appreciation

for advancement.

III/1V

ABSTRACT .

ACKNOWLEDGMENTS

LIST OF TABLES

LIST OF FIGURES.

LIST OF APPENDICES

INTRODUCTION .

OBJECTIVES

BACKGROUND .

Oxygen Rancidity

TABLE

OF CONTENTS

Material Description and Concept . . .

LITERATURE REVIEW
MATERIALS AND METHODOLOGY

3-Phase Design .

Equipment.

Sample Preparation

General Comments

RESULTS AND DISCUSSION

SUMMARY

CONCLUSIONS

REFERENCES

APPENDICES

iv

vi

. vii

.viii

10

10

ll

18

53

55

56

58

Table No.

I

II

III

IV

VI

VII

VIII

IX

XI

XII

XIII

XIV

XVI

LIST OF TABLES

RUN RATIOS AND SAMPLE DIMENSIONS .

GENERAL DATA FOR ALL RUNS. . . . .

VOLUME VS. TIME DATA FOR RUN 1 OF

RATIO 18.6:1 (cc/cmz)

VOLUME VS. TIME ATA
RATIO 2:1 (cc/cm )

VOLUME VS. TIME DATA
RATIO 8.3:1 (cc/cmz)

VOLUME vs. TIME DATA
RATIO 4.1:1 (cc/cmz)

VOLUME VS. TIME DA A
RATIO 4.1:1 (cc/cm )

COMPUTED RESULTS FOR

(RATIO 18.6:1) , . ..

COMPUTED RESULTS FOR
(RATIO 2:1)

COMPUTED RESULTS FOR
(RATIO 8.3:1) . .

COMPUTED RESULTS FOR

(RATIO 4:1 — before moisture), .

FOR

FOR

FOR

FOR

RUN

RUN 2 OF

RUN 3 OF

RUN 4A OF

RUN 4B OF

3

4A

COMPUTED RESULTS FOR RUN 4B
(RATIO 4:1 - after moisture} ,

PAIRING COMBINATIONS FROM RUN 3 FOR

RUNS 4A AND 4B . . .

MOISTURE ANALYSIS DATA FROM RUN 4A

DATA COMPARISON BETWEEN RUNS 4A

AND 4B

COMPUTED DATA FOR HEADSPACE OXYGEN

REDUCTION OVER TIME

vi

Page
~14

'21

022

-24

~26

~29

-3O

.31

.32

.33

-34

~35

-37

.39

.40

.50

LIST OF FIGURES

Figure Page

I THE FOUR BASIC STAGES OF MANOMETER
UTILIZATION o o o o I o o o o o o o o o o o o o o o o o o o 12

II DESCRIPTION BY MEAN SAMPLE FOR EACH RUN . . . . . . . . . . 41

III HIGH, Low, AND AVERAGE HALF—LIFE OF
RUIJ 1- O O C O O C O O O O O 0 O O O O O I O O O O O O O O O 4 2

IV HIGH, LOW, AND AVERAGE HALF-LIFE OF
RUN 2 C O O O O O O O O O O O O O O O O O O O O O O O O O O 4 3

V HIGH, LOW, AND AVERAGE HALF-LIFE OF

RUN 3 I I O O O O O O O O O I O O O O O O O O O O O O O O O 44

IV HIGH, LOW, AND AVERAGE HALF—LIFE OF
RUN 4A. 0 O O O C O O O O O O O O O O O I O O O O O O O O O 45

VII HIGH, LOW, AND AVERAGE HALF—LIFE OF
RUN 4B. O O O O O O O O O O O C O O O O O O O O O O O C O O O 46
VIII REDUCTION OF HEADSPACE OXYGEN OVER TIME . . . . . . . . . . 51

vii

LIST OF APPENDICES

Appendix Page
A HEADSPACE OXYGEN ANALYSIS PROCEDURE . . . . . . . . . . 58
B COMPUTER PROGRAM . . . . . . . . . . . . . . . . . . . . . 65

C ‘MOISTURE CONTENT ANALYSIS PROCEDURE . . . . . . . . . . . 69

viii

INTRODUCTION

Packaging affects the storage quality of food products in
various ways. Its primary function is to control and protect against
environmental factors affecting the quality and integrity of the
product. Shelf—life of a product is the predominate concern of the
food packaging engineer. Once a product has completed final process-
ing and packaging, assurance must be provided that the product will not
deteriorate significantly before its intended consumption. The shelf-
life of a packaged product is an established period of time, under assum-
ed conditions, after which deterioration may cause it to be substandard.
Environmental factors affecting the deterioration mechanisms of these
products include thermal stresses, wavelengths of light, concentration
of water vapor, oxygen concentration, and biological organisms. Al-
though most degradation mechanisms of food products are influenced by
a combination of these environmental factors, the primary mechanism
for deterioration in most foods may be significantly attributed to one
of these factors. The factor of primary concern in this study associated
with primary food packaging is that of oxygen concentration. The in-
vestigation will analytically examine the antioxidative influence of
an impregnated oxygen scavenger packaging film incorporated as a con-

tingent inner package oxygen consumption device.

OBJECTIVES

The primary objectives of this project are to quantitatively
determine the effectual relationship of the above mentioned oxygen
scavenger film as an inner package antioxidant device; to hypotheti-
cally apply this relationship to a packaged food product; and to
provide information relevant to this material in association with

the current state-of—the-art food packaging technology.

BACKGROUND
Oxygen Rancidity

Oxygen rancidity is primarily associated with the deterioration
of fats and oils. This rancidity results from a chemical reaction
where long chained unsaturated fatty acids are broken into smaller
chained fatty acids. The reaction is based on the intermediate for-
mation of peroxides where unsaturated fatty acids are subjected to
oxidation at their double bonds. The resultant smaller chained
fatty acids produce the familiar objectionable odors and are primar-

ily responsible for the rancid taste (Desrosier, 1970):

Material Description and Concept
There currently exist many FDA approved food additives which

serve as antioxidative devices, each having its' own advantages and
disadvantages. Recent developments in the area of oxygen scavenger
mechanisms incorporated in packaging materials has shown great poten—
tial as a successful and efficient antioxidative device (Kuh, 1970;
Food Processing, 1973; Peters, 1974: Zimmerman, 1974). One such film
has been developed and is currently manufactured by the American Can
Company, Greenwich, Connecticut. The material consists of polyester/

adhesive/foil/Surlyn/palladium catalyst/Surlyn. It is commercially

3

identified as Maraflex 7—F. The principal mechanism of antioxidation
is the formation of water vapor from headspace oxygen and hydrogen
within a moisture vapor impermeable cell. The gas barrier proper-
ties of the Surlyn film are such that they allow permeation of both
oxygen and hydrogen molecules through and into the palladium catalyst
area. Within this area the water formation reaction occurs.

A highly critical prerequisite to the successful implementa-
tion of this material, of course, is the need for hydrogen and oxygen
to be present in the headspace. This is accomplished by gas flushing,
with a gas mixture of 8% hydrogen and 92% nitrogen, prior to final
package sealing. Commercial automated food packaging systems for
employing a nitrogen gas flush operation will exhaust approximately

98% to 99% of the headspace oxygen.

LITERATURE REVIEW

Kuhn, et a1 (1970) reports that work done by Mucha, et a1 (1961)
involving flavor stability of foam spray dried whole milk over extended
storage periods require low oxygen concentration to prevent detrimental
flavors. Significantly, samples stored at 0.1% oxygen atmosphere re-
sulted in a better flavor than those stored at 1.0%. In conjunction
with this aspect, Kuhn further reports that a study by Berlin, et a1
(1963) concludes that residual oxygen levels above those necessary to
maintain dry milk flavor stability may be accounted for by entrapped
oxygen gas with the product particles. At the time of Kuhn's report,
there were three general methods available for removing residual oxygen
from packaged products. One was the employment of a product exposed to
vacuum for an extended duration of time. Although somewhat successful,
it proved to be an expensive operation (Kurtz, et a1 1967). Second was
the incorporation of Glucose Oxidase as a deoxidative device in nitrogen
flushed packages. For dry products the mechanism must be separately pack~
aged and implemented as an insert. This mechanism requires the presence
of glucose and water for reaction. Although this method has been proven
effective (Kurtz et a1, 1957), problems occur which are solely generic

to the package insert and its integrity. The third and final method

6

reported by Kuhn is the use of palladium or platinum pellets for cata—
lyzing the reaction 2H +0 «OZH 0 as devised and proven by King (1955),
and Abbott et a1, 1961? Initiil tests conducted on a film constructed of
paper/PEIfoil/scavenger/PE proved successful. However, the effective-
ness was short lived due to excessive pinholing in the foil. A second
laminate construction consisted of polyester/Saran/polyvinyl alcohol/PE/
scavenger/PE resisted flex cracking and pinholing previously foil at—
tributed. Furthermore, the residual oxygen levels of the packages were
between 0.15% and 0.5%. A storage study conducted on 10 pouches held

at 73°F and 50% R.H. over a 24 week period resulted in concentration

levels between 0.00% and 0.38%. An article published in the 1973

September issue of Food Processing entitled "Oxygen Scavenger Package

 

Stops Oxidation, Extends Shelf—Life" further illuminated the success-

ful use of American Can's oxygen scavenger film. This current film re-
presents a third laminate and is constructed of polyester/adhesive/
foil/Surlyn/catalyst/Surlyn. With efficient commercial packaging
machines that exhaust about 98% of oxygen gas, approximately 2% residual
oxygen remains in the package headspace. By applying the 8% hydrogen/92%
nitrogen gas mixture flush, the inherent attributes of the scavenger
mechanism have efficiently consumed most residual oxygen. In a six
month study involving packaged spray dried whole milk, packages stored

at extreme temperatures and relative humidity (lOOOF and 90% R.H.)

were organoleptically rated the same as the control stored at 00F.
Furthermore, a storage test conducted on fresh meat employing the scavenger
film stored at 32°F doubled the original shelf-life of four weeks to

that of eight weeks.

Peters (1974) offers further evidence in support of the scavenger

film's effectiveness for extending shelf—life of oxygen sensitive

7

packaged products. He reports that pouches containing from one to four
ounces of powdered milk with initial oxygen levels between 0.5% and 2.5%,
after 24 hours, had been reduced to between 0.1% and 0.2%. And, after
an additional 24 hours levels were reduced to zero. Peters suggests
that with this film such antioxidant ingredients as BHA and BHT may be
removed from products to the advantage of marketing strategies.
Additional reference is made to a study by Bishov et a1 (1971) on
freeze-dried food items representing vegetables, fruits, meat, fish, and
poultry. These items were separately containerized with an oxygen cataly-
st of palladium pellets and sealed after being flushed by a mixture of
5% hydrogen and 95% nitrogen, and stored for 6 months at 1000F. The
results rated the experimental items comparable to the original products.

An article entitled "Scavenger Pouch Protects Oxygen-Sensitive
Foods," by Zimmerman, et a1 (1974) explains American Can's development
of the current scavenger films designated as Maraflex 7-F. Evolution
of their previous laminate film (polyester/Saran/polyvinyl alcohol/
polyethylene/scavenger/polyethylene) to the present construction of
polyester/foil/Surlyn/catalyst/Surlyn as primarily the result of improved
laminating qualities and increased barrier properties. With the in—
corporation of Surlyn, seal area contamination and activity level
problems were resolved. "Activity" as defined by the authors is
derived from the amount of time consumed in obtaining one-half of the
initial headspace oxygen concentration in a calibrated pouch. Twelve
hours is generally accepted by the authors to be adequate for most
food products. Furthermore, Surlyn provided greater gas permeation
rates than did the polyethylene, thus allowing greater flow of both

oxygen and hydrogen into the catalytic cell area. Additionally, the

8
water vapor transmission rate of the Surlyn provided a positive
barrier against permeation of reaction produced moisture. Together
with the Surlyn, the external layer of foil and polyester provided
additional barrier and strength characteristics. Corresponding with
previous shelf-life studies, it was further reported that American
Can has recently concluded a 1 year storage study on 4-ounce, gas
flushed, scavenger packages containing whole milk powder. Samples
were stored at the following conditions: 450F/90% R.H.; 730F/50%
R.H.; 1000F/20% R.H.; and lOOoF/90% R.H. The control sample was
stored at 00F. The flavor taste panel evaluating the product record~
ed no flavor change during the 12 month period.

Marcus Karel (1974) in an excellent article entitled "Packaging
Protection for Oxygen—Sensitive Products" presents and discusses the
effects packaging has on the control of oxygen against oxygen sensi-
tive food products. This includes information regarding oxidation
as a function of oxygen pressure, the effect of diffusion on final
oxidation, deterioration of organoleptic quality, and an explanation
and mathematical derivation of activated diffusion as associated with
a materials permeability coefficient. Additionally, Karel offers
data generic to various material properties and their effect on permeabi-
lity as well as determining optimal material combinations in achieving
maximum use of steady state concentrations for respirating food
products. In concluding his article, Karel refers to three anti-
oxidation systems previously mentioned by Kuhn (197) available for

food packaging: l) The use of a separate container employed as an

inner package oxygen scavenging device similar to a desiccant package;

2) the use of enzyme glycose oxidase; and 3) the incorporation of
an oxygen scavenger impregnated film pouch as produced by the American
Can Company to remove residual headspace oxygen concentration, the

subject for which this thesis is directed.

MATERIALS AND METHODOLOGY
3—Phase Design
The research design entailed a 3—phase integrated study. The
first phase involved the preparation of oxygen scavenger film samples,
equipment, and apparatus. The second phase measured oxygen uptake of
the various sized samples of the scavenger film. The third and final
phase of this study applied the derived data from phase two to a

hypothetical packaged food product for design consideration.

Equipment

The study employed a Gilson model CR 20 differential respirometer
as the primary apparatus for the second phase of this study. The
respirometer was used to analytically measure oxygen uptake of the
oxygen scavenger film. The respirometer is based on the principle that
at constant temperature and constant gas volume any changes in the
amount of gas can be measured by changes in its pressure (Umbreit,
1964). The primary component of the respirometer is the volumometer.
The volumometer consists of a manometric tube with indicating fluid,
sample flask, reference flask, micrometer, periscope, and inlet port
valve. The volumometer measures gas changes effected by the sample.

This is accomplished in a closed system whereby the volume of gas

10

ll

absorbed is replaced by an equal volume of dyed indicating fluid. The
fluid is in a manometer located upstream from the sample flask. The
fluid level of the manometer is returned to its original position,

as viewed through the periscope, by manually turning the micrometer
shaft. The shaft is digitally indexed in microliters and upon final
equilibration, total volume change may be directly read off the shaft.
Figure I offers a representation of the initial gas flushing followed
by equilibration, oxygen consumption, and reequilibration. Although
the flasks are submerged in a constant temperature water bath, the
reference flask is used to compensate for any extraneous temperature

and pressure changes affecting manometer sensitivity.

Sample Preparation

Film samples were prepared from American Can Company's oxygen
scavenger film laminate identified as "Maraflex 7—F." The scavenger
web construction is 0.5 mil polyester/0.35 mil Al. foil/15 1b Surlyn/

1 1b Palladium catalyst/12 lb Surlyn. Note that the basis area is 3000
ftz, so that 15 lb Surlyn represents approximately 1 mil thickness.

The web material (2500" x 9 9/16) was received from American Can in
September 1974.

Individual samples were measured with a standard rule and cut to
size by an exacto knife. Approximately 3 feet of leader material was
run off prior to sample preparation to reduce the probability of sample
contaminations. Samples were prepared and handled as aseptically as
possible using metal tongs, surgical gloves and a wiped down work area

using a 70% solution of ethanol. After sample preparation, they were

12

 

 

 

 

 

 

 

 

 

 

 

 

GAS FLUSHING INITIAL EQUILIBRIUM

 

4.;

I
‘V

 

 

 

 

 

V‘-

 

 

 

 

OXYGEN CONSUMPTION REEQUILIBRIUM
(MICROMETER ADJUSTMENT)

Figure I — The four basic stages of manometer utilization

l3

grouped by size and placed into a closed container awaiting experiment
implementation. Sample dimensions for the 3 primary runs are given in
Table I.

The ratios were established from the active surface area of the
material samples and volumeter headspace volume. The headspace volume
was determined to be 30 cc. Slight differences were noted in headspace
volumes, and were attributed to variance in manometer indicating fluid
and glassware dimensionable integrity. It was felt that these variances
were not significant enough to critically effect the results of the
study and, therefore, 30 cc of headspace volume was used in the calcu-
lations.

The ratio for Run 1 of 18.6:1 was derived at the convenience of

the 1/2" x 1/2" dimension. Run 2 however, at a ratio of 2:1 was obtained
by predetermining the required surface area equivalent to that ratio
and then physically providing this area. Due to the configuration of
the sample flasks, the resulting scavenger material was of two pieces.
One piece of rectangular dimensions, encircled the neck area while the
second was of frustum construction adhering to the internal conical
profile of the flask. Run 3 of ratio 8.3:1 was designed such that the
combination of two Run 3 samples would produce a 4:1 ratio (i.e.,
3.63 cm2x2 = 7.62 cmz; 30 cc/7.26 cm2 = 44131). Therefore, it provided
data of comparability with not only Run 3 at 8:1 but also Run 2 with
a 2:1 relationship. Similarity of material samples were determined by
correlating the computed specific activity coefficients.

Sample flasks were 17 m1 of the Erlenmeyer configuration. All

sample flasks were cleaned prior to the experiment using a dichromate

14

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15

method. Sample flasks were readied by placing a scavenger film sample
of prescribed surface area into each Of sixteen sample flasks using
metal tongs. The flasks were then attached to the manometer and readied
for the gas flushing and sealing phase. All glass joints and valves
requiring lubrication were so checked and prepared. Manometer indi-
cating fluid was checked for proper levels and purity. Application

of lubricant to the interfacing surfaces securing the sample flask

was accomplished after insertion of the sample material. This was to
preclude possible contamination of sample material.

Gas flushing was accomplished using a certified gas mixture of
91.5% N2 and 8.5% H2. To facilitate the flushing process, a 1/8" copper
tube 6 inches in length was attached to a regulated gas source. With
the inlet port valve removed, the 1/8" tube was inserted through the
inlet port valve sleeve and into the sample flask. The sample flask
was then flushed with the gas mixture for a period of 30 seconds at
3 psig. Immediately following flushing the inlet port valve was
quickly replaced. The replacing of this valve requires a practiced
technique which prohibits a blow back of indicating fluids if done too
quickly or compromization of headspace gases if done too slowly.

Prestudy flushing practice, checked with a Varian 90-P gas
chromatograph containing a 5A molecular 50/80 column for analysis,
resulted in a consistent technique whereby the average gas flushing
and sealing resulted in oxygen headspace content of 1-3%. The tech-
nique for determining headspace oxygen content is shown in Appendix A.
Additionally, it was found that by presetting the manometer micrometer
at 40 ul, an optimum starting registration, after gas flushing and

instrument equilibration, could be achieved.

16
After flushing and micrometer readjusting, the manometer was
attached to the respirometer and submerged in a water bath held at a
constant temperature of 22.500 : 0.5C. Micrometer readings and time
were then recorded. A total of 20 manometers were used for Runs 1,
2, and 3, 16 of which contained sample material and were gas flushed.
The remaining 4 manometers were used for reference, and contained no
sample material. Of these four, two were gas flushed and two were

not, yet all four were submerged with the others.

General Comments

Data obtained from the experimental runs was submitted to statis-
tical evaluation employing a computer program developed by Dr. Wayne
Clifford of the School of Packaging, Michigan State University. This
program is offered at Appendix B. Much of the oxygen uptake exceeded
the measuring capacity of the manometers. Hence, total volume uptake
could not be directly determined. The computer program utilized
mathematical and statistical techniques to arrive at an estimation of
final volume uptake. The program entails 3 parameter functions of
which 2 parameters utilize the least squares method, and the third
uses a 1 dimensional search technique. This search technique is
described by Wilde (1964) as the golden section search. Essentially,
this 3 parameter functional program combines both mathematical and
statistical models, and estimates total oxygen uptake. In a bracket-
ing procedure, the estimates applied to linear regression analysis were
correlated in arriving at the final estimate of total volume uptake.

Data produced by the program for each sample included values for total

17

initial oxygen, A and B parameters for the linear equation, corre-
lation coefficient for the regression model, and the error for the

sum of squares of the deviation for the time satisfying the data.

RESULTS AND DISCUSSION

A total of 5 runs were conducted for this study. Fifty samples
were initially started out of which 40 survived their periods of
investigation, and were used in the compilation and analysis of this
study. A breakdown by run is offered in Table II.

Ratios were based upon headspace volume versus the surface area
of sample material. Headspace volume of the sample cells was es-
tablished as 30 cc and was assumed to be final and, therefore, held
constant throughout the study. Surface area of the samples was varied,
hence, the variability of ratios for Runs 1, 2, 3, and 4.

'Raw data recorded for each run by sample is available in Table
III through Table VII. These values represent actual readings taken
during the extent of the experiment. Tables VIII through Table XII
offer the computerized interpretation of the raw data. Included with
these generated data are calculated values establishing the estimated
half-life and specific activities for the samples studied.

Specific activity is defined as the amount of oxygen consumed in
grams—per surface area of material—per hour-at one atmosphere of oxygen

pressure. This is mathematically defined by the following:

18

19

Activity Material of 0

Rate Of 02 = - Film Specific] [Area of Concentration
2

Consumption

to find the rate of 0 consumption, an expression for the mass of 0

2

inside the container is needed. This will come from the ideal gas

law:
P V=.'_n_RT (l)
O M
2
where:
P = Partial pressure of O
02 2
V = Volume (cc)
m = Mass (grams)
M = Molecular wt (32g/mole)
R = Gas constant (82.06 cc-atm/oK-mole)
T = Temperature 0K

Solving Equation 1 for m;

mam.
RT 0 (2)

2
the mass of oxygen in the container may be determined.

The time rate of change of m is simply the first time derivative

of Equation 2:

 

dt RT dt (3)

 

1734.. 2 = —Sa.Af.PO (4)

20

This equation may be simplified to:

 

dPO
2 = —BP0 (5)
dt 2
where:
B = Sa Af.Rl (6)
MV
where:
Sa = Specific Activity (g/cmZ/atm/hr)
Af = Area (cmz)
B = Straight line parameter (slope)

When Equation 5 is solved, it yields:
I

_ —Bt
P — P e (7)
02 02
An alternative expression is:
I
1n P0 = ln PO - Bt (8)
2 2

Half—life is defined as that period of time expended during the
consumption of one—half the volume of headspace oxygen. It is
mathematically defined as:

or

tl/2 = .693/B
It was anticipated that by increasing the surface area of the
oxygen scavenger material while maintaining a constant headspace
volume the half—life expectancy of oxygen uptake would decrease.

This was evidenced in Runs 1, 2, and 3. Mean results may be seen

in Table II. Run 1 with a volume to surface area ratio of 18.6:1

21

 

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«N.m sq.woa mm.©mm mo.mNH q.HH «a «H Hum.m m
ow.q om.Aa AN.H©¢.N s.s~ s.os A m HAN N
mm.¢ AN.qu mm.Nwm o.omm o.wH m 0H Hum.wa H

OH x mm N\H o .

m+ u > A.msnv cam mo ::m\wmwm mmamfimm mwamamm

.w>< .w>< .w>< cosumudn .w>< .oz .w>< ram .02 afiwom .oz owumm sum

 

mZDm AA< mom «Eda A<mmzm0

HH mqm<H

 

22

 

 

 

0.0mm o.mmq 0.0mm o.NmN 0.0mm o.muq 0.0mm o.mom 0.0mm o.mns ma
o.NHm o.o¢¢ o.NHm o.HmN o.NHm o.ao¢ o.NHm o.qu o.NHm o.ooq NH
o.wwq o.¢Nq o.mwN o.m5N o.mwN o.ch o.wwN o.¢mq o.me o.mqq ea
o.qu o.¢os o.qu o.moN o.¢oN o.omq o.qu o.omq o.ch o.mN¢ ma
m.msN 0.0mm m.qu o.NmN m.m¢H 0.0Hq m.qu o.cm¢ o.¢qN o.noq «a
o.osN o.me o.oqN o.w¢N o.oqN o.woq o.oqN o.qu o.o¢N o.m¢m NH
o.ama o.wmm o.mmH o.NNN o.omH o.wom o.mmH 0.05m o.mmH o.qu NH
o.NoH o.Nmm o.NmH o.wHN o.NmH o.mom o.NmH o.Hcm o.NmH o.oqN Ha
o.mNH o.mHm o.mna o.HHN o.mNH o.wqm o.mna 0.5mm o.mNH o.mNm OH
o.on o.aom o.woa 0.00N o.on o.qu o.woa o.amm o.on o.nam m
o.HmH o.mmN o.HmH o.mmH o.HmH o.mNm o.HmH 0.00m o.HmH o.omN w
o.qqa o.wwN o.¢¢a o.m¢H o.qqa o.qu o.qqa c.m¢N o.¢qa o.mwN A
m.©NH o.HNN m.oNH o.¢wH m.cNH o.qu m.cNH o.woN 0.0NH o.nmN o
o.ONH o.moN 0.0NH o.<ma o.ONH o.mwN o.ONH o.omN 0.0NH o.qu m
o.ooa o.qu o.ooa o.aoH 0.00H o.smN o.ooa o.mNN o.ooa o.mHN q
0.0m o.mmN o.om o.moa 0.0m o.qu 0.0m o.mHN o.©m o.HHN m
o.qm o.cHN o.qn o.HmH o.¢m o.NON o.qw o.NwH o.¢n o.mNH N
o.Nm c.0mH o.Nm o.nma o.Nm o.mmH o.Nm o.mqa o.Nm o.nma H
mu: was ms: was ms: was ms: was mus was
OH
mmamamm

 

ANEODS no.3 Seas so

H 23m mom ¢H<Q WZHH .m> MEDAO>

HHH m4m<H

 

23

 

 

 

0.0mm o.moq o.omm o.mqs 0.0mm o.HHm 0.0mm o.owm wH
o.NHm o.nom o.NHm o.om¢ o.NHm o.omq o.NHm o.mom NH
o.wwN o.mmm o.wwN o.qu o.wwN o.mw¢ o.wwN o.qu 0H
o.<oN o.onm o.s©N o.moq o.¢oN o.Noq o.qu 0.0Nm mH
m.a¢N o.mmm m.qu o.wmm m.qu o.oq¢ m.m¢N 0.0Hm «H
o.oqN o.mqm o.oqN o.wwm o.oqN o.nm¢ o.o¢N o.Hom mH
o.mmH o.HHm o.m¢H o.mqm o.mmH o.mmm o.mmH o.HmN NH
o.NmH 0.00m o.N¢H o.mqm o.NmH o.me o.NmH o.qu HH
o.mNH o.maN o.mNH 0.5Nm o.mNH o.Hom o.mNH o.NNN OH
o.on o.wwN o.w©H o.NNm o.moH o.mmm o.w©H o.HNN m
o.HmH o.nmN o.HmH o.qom o.HmH o.¢Nm o.HmH o.HON w
o.<qH o.w©N o.qu o.mmN o.qu o.on o.qu o.mmH m
m.oNH o.qu m.oNH o.NNN m.oNH o.wwN m.oNH o.mNH o
0.0NH o.NQN c.0NH o.NoN o.ONH o.mNN o.ONH o.moH m
o.OOH o.omN o.OOH o.me 0.00H o.N¢N o.o0H o.m<H q
0.0m o.©NN o.©¢ o.HmN o.©m o.nmN 0.00 o.NMH m
o.qn o.mON o.qm o.HON o.qm c.HON o.qn 0.0HH N
o.Nm o.me o.Nm o.HNH o.Nm o.moH o.Nm o.mw H
mm: mHs mu: st my: mHs was wHD
0H HH
mMHaEmm

 

Amso\00v Huo.ms oHeam so

H 25m mom <H<Q MZHH .m> MZDHO>

Aw.uaoov HHH mHm<H

 

24

 

 

 

00.NN 0.000 «0.NN 0.N«0 NH
N0.0N 0.0Nm 00.0N 0.000 00.0N 0.0H0 HH
mm.0H 0.00N 00.0H 0.0Nq 00.0H 0.00m 0H
«0.NH 0.00N N0.NH 0.0N0 m0.NH 0.00m 00.NH 0.000 00.NH 0.000 m
0N.m 0.00N 0N.0 0.000 00.0 0.00N NN.m 0.000 0N.m 0.0HN 0
00.5 0.HNN H0.N 0.0Hq «0.5 0.00N N0.N 0.0Nq 00.n 0.00H n
H0.0 0.00N «0.0 0.000 «0.0 0.NON 00.0 0.000 00.0 0.0NH 0
00.0 0.00N 00.0 0.NHm 00.0 0.00H m0.0 0.000 00.0 0.HHH 0
0m.q 0.00H mu.¢ 0.0nN 05.0 0.NOH NN.< 0.H00 00.0 0.50 q
N0.N 0.NOH 00.N 0.00H 00.N 0.NHH 00.N 0.HNN 00.N 0.00 m
N0.H 0.00H 00.H 0.00H 00.H 0.00 00.H 0.00H 00.H 0.0H N
00. 0.NOH N0. 0.NHH N0. 0.00 00. 0.00H 00. 0.0 H
mun mHD mun mH: mun mHD mun wH: mun mHs
0H 0H
memEmm

 

ANEOBS HAN 8.32 no

N 20% mom <H<Q mZHH .m> MZDHO>

>H MHO<H

 

25

 

 

00.0N 0.0H0 NH
N0.0N 0.00m N0.NN 0.500 HH
05.0H 0.000 05.0H 0.000 0H
00.NH 0.00N 50.NH 0.0Nm 0
0N.0 0.0HN 0N.0 0.HON 0
00.5 0.55H 00.5 0.NHN 5
H0.0 0.m0H 00.0 0.N5H 0
00.0 0.00H N0.0 0.00H 0
05.0 0.5HH 05.0 0.00H 0
N0.N 0.05 N0.N 0.00H m
N0.H 0.00 N0.H 0.H5 N
00. 0.Nm N0. 0.00 H
mu: mHs was mH:
0H 5H

 

mmHmBmm

 

ANeO\OOV Hum oHsam no
N zpm mos <H<n mzHe .m> mzsqo>

Aw.uaoo0 >H mamas

 

26

 

 

 

0H.HOH 0.000 0H.HOH 0.H00 00.00H 0.050 00.HOH NH
5N.H0 0.000 00.H0 0.0N0 H5.00 0.H00 00.H0 0.0H0 HH
5N.05 0.00N 00.05 0.000 H5.05 0.HNO 00.05 0.000 0H
HH.N5 0.00N 0H.N5 0.050 00.H5 0.000 00.H5 0.H00 H0.N5 0.00N 0
00.00 0.00N 00.00 0.N00 0H.00 0.5H0 00.00 0.00N H0.00 0.05N 0
00.00 0.0HN 00.00 0.000 H0.00 0.500 00.00 0.0NN 0H.00 0.50N 5
00.N0 0.NON 00.00 0.00N 00.N0 0.NNO 00.N0 0.00N 0H.00 0.00N 0
H5.0N 0.05H 05.0N 0.NON 0N.0N 0.000 0H.0N 0.00H 00.0N 0.NHN 0
N0.0N 0.50H 00.0w 0.5HN 00.00 0.000 0N.0N 0.00H 00.0w 0.00H 0
0N.0H 0.HOH 5N.0H 0.00H H0.5H 0.00N 00.5H 0.0NH N0.0H 0.05H 0
05.5 0.NHH 05.5 0.50H 5N.5 0.00H 5H.5 0.00 00.5 0.00H N
00.0 0.00 00.0 0.5NH 00.N 0.00 N5.N 0.00 00.0 0.0HH H

mun mHD ms: mH: my: mH: my: mHs mun mH: I

0 5 0 0 0
mHmEmm

 

ANau\ro Hum.w oHeam so
m zen mom <H<n mzHa .m> mzsao>

> WHQ¢H

 

27

0H.HOH

 

 

 

NN.H0 0.000 00.00H 0.500 NH
HN.H0 0.500 NN.00 0.0H0 0N.H0 0.000 00.00 0.000 5N.H0 0.5N0 HH
HN.00 0.050 00.N5 0.00N 0N.00 0.000 H5.05 0.000 5N.05 0.N00 0H
00.N5 0.000 00.00 0.05N 0H.N5 0.000 00.H5 0.0N0 0H.N5 0.000 0
00.00 0.HNO N0.00 0.00N 00.00 0.0N0 00.00 0.000 00.00 0.000 0
00.00 0.H00 00.N0 0.00N 00.00 0.000 00.00 0.000 00.00 0.000 5
N0.N0 0.0N0 00.N0 0.0HN 00.N0 0.H00 00.N0 0.5N0 00.N0 0.000 0
00.0N 0.00N 00.0N 0.00H 00.0N 0.00N 0H.0N 0.N5N H5.0N 0.0N0 0
05.0N 0.00N 55.0N 0.00H 05.0N 0.00N 0N.0N 0.00N N0.0N 0.00N 0
0N.0H 0.00H NN.0H 0.H5H 0N.0H 0.NHN 05.5H 0.0HN 0N.0H 0.00N 0
00.5 0.0NH 00.5 0.NOH 00.5 0.00H 5H.5 0.NOH 05.5 0.05H N
NN.0 0.00 0N.0 0.00H 0N.0 0.N0 N5.N 0.HOH 00.0 0.00H H

my: mH: my: mH: mun mHs my: mH: ms; mH:
0H 0H NH 0H
wwHaawm

 

A~a0\ro Hum.m oHsam so
m zsm mom <H<n mzHH .m> mzeqo>

Ae.uaoo0 > mam<e

 

28

 

 

 

00.00H 0.050 00.HOH 0.000 NH

0H.H0 0.H00 0H.00 0.050 0H.H0 0.000 HH

HH.05 0.0N0 0H.05 0.0N0 0H.05 0.000 0H.05 0.000 0H
00.H5 0.000 N0.N5 0.000 N0.H5 0.000 00.N5 0.000 0
00.00 0.000 N0.00 0.H00 N0.00 0.0H0 00.00 0.NNO 0
00.00 0.5N0 00.00 0.0N0 00.50 0.00N 00.00 0.H5N 5
00.N0 0.000 00.N0 0.0H0 00.H0 0.00N 00.N0 0.00N 0
50.0N 0.N00 00.0N 0.00N 00.0N 0.0HN 00.0N 0.NHN 0
05.0N 0.0N0 N5.0N 0.00N 05.NN 0.00H 05.0N 0.NOH 0
0H.0H 0.NON 0H.0H 0.0HN 5H.5H 0.05H 0N.0H 0.05H 0
N0.5 0.00H N0.5 0.00H 00.0 0.05H 50.5 0.HOH N
0H.0 0.00H 0H.0 0.HNH 0H.N 0.50N NN.0 0.0HH H

my: mH: mun mHs was mH: mun mH:
0H 5H 0H 0H
mmHmamm

 

Amao\000 Hum.w OHHam so
m zsm Mom «was mzHa .m> mzpqo>

Ae.u:oov > msm<e

 

29

 

 

 

00.50H 0.050 N0.50H 0.00N 00.50H 0.NON 00.50H 0.00N NH
00.00H 0.000 N0.00H 0.NON 00.50H 0.0NN 00.00H 0.50N 00.00H 0.NON HH
00.0NH 0.000 00.0NH 0.00N 00.00N 0.5HN N0.0NH 0.0NN 00.0NH 0.HON 0H
00.05 0.0NN N0.05 0.00H H0.0NH 0.00H 00.05 0.HOH 50.05 0.NOH 0
00.N0 0.H5H N0.N0 0.50H 00.05 0.00H 00.N0 0.00 00.N0 0.0NH 0
00.00 0.00H N0.00 0.NOH 00.N0 0.05 00.00 0.00 00.00 0.0NH 5
00.00 0.00H N0.00 0.00 00.00 0.00 00.00 0.50 00.00 0.0HH 0
00.0N 0.00H N0.0N 0.00 00.00 0.H0 00.0N 0.H0 50.0N 0.00 0
00.0N 0.00 N0.0N 0.00 00.0N 0.H0 00.0N 0.00 50.0N 0.00 0
00.0N 0.00 N0.0N 0.00 00.0N 0.0N 00.0N 0.00 50.0N 0.50 0
00.HN 0.00 N0.HN 0.00 00.0N 0.0N 00.HN 0.00 50.HN 0.05 N
0H.NH 0.00 0H.NH 0.0N 00.HN 0.0N 5H.NH 0.0H 0N.NH 0.00 H
my: mH: mun mH: my: mH: my: mHD mun mHn
0H 0 5 0
mMHQEmm

 

ANEO\OOV HAH.0 oHeam so
<0 22m mom <a<n msz .m> mzsqo>

H> mam<8

 

30

 

 

 

00.00N 0.000 50.00N 0.000 0H.00N 0.0H0 NH.00N 0.000 NH.00N 0.050 NH
00.0NN 0.000 50.0NN 0.00N 0H.0NN 0.000 NH.0NN 0.000 NH.0NN 0.H00 HH
00.HOH 0.000 50.HOH 0.00N 0H.HOH 0.000 NH.HOH 0.000 NH.HOH 0.500 0H
00.00H 0.00N 50.00H 0.HHN 0H.00H 0.00N NH.00H 0.0N0 NH.00H 0.000 0
00.50 0.00N 50.50 0.05H 0H.50 0.00H HH.50 0.0HN 0H.50 0.0HN 0
00.N5 0.00H 50.N5 0.00H 00.N5 0.HOH H0.N5 0.00H 00.N5 0.00H 5
50.N0 0.0HH 50.N0 0.00H 00.N0 0.50H HH.N0 0.0NH 0H.N0 0.00H 0
50.50 0.00H 50.50 0.00N 00.50 0.00H HH.50 0.0HH 0H.50 0.NNH 0
00.0N 0.00 50.0N 0.NNH 00.0N 0.00H HH.0N 0.00 0H.0N 0.00 0
00.0N 0.00 50.0N 0.5HH 00.0N 0.00H HH.0N 0.N5 0H.0N 0.00 0
50.HH 0.00 00.HH 0.HHH 0H.HH 0.00 NH.HH 0.00 0H.HH 0.50 N
00.0 0.00 50.0 0.HHH 0H.0 0.50 NH.0 0.00 0H.0 0.00 H
mu: mH: was mH: my: mHD my: mH: mun mH:
0H
mmHaEmm

 

ANEO\OOV HAH.0 oHaam mo

HH> MHO<H

00 200 mom <H<Q mEHH .m> MZDHO>

 

31

 

HHOH.0: 00N50.0 0000.0: 00.N 0N.000 0H.0H0 0H
0H00.0: 000H.0 0000.0: 0H.0 00.55H H0.000 0H
5000.0: 000N.0 N000.0I HN.0 00.05H 00.000 NH
0005.0: 00N00.0 N000.0I 00.N 00.000 N0.000 HH
50000.0: 050H0.0 H000.0: N0.H 00.0H5 05.00N.H 0H
50NH.0: HOH00.0 0000.0: 00.H 5N.000 05.500 5
0N50.0: 5000.0 0000.0: 00.5 00.00H 00.N00 0
500N.0: 00HH.0 0000.0: N5.0 0N.HON 00.H05 0
0000.0: 05H00.0 5000.0: 50.0 N0.05H 05.000 0
N+0H x 0 0H s uGOHonwmou Au£\aum\NSo\800 Amunv 5000 .02

Hmuosmumm NWOHHM GOHumHmuuou 0H x mm N\H 0 mHmamm

0+ u >

 

Aauo.mH oHsamv
H zsm mom measmmm omsamzoo

HHH> 04008

 

32

 

 

NH MHm<H

moss.o- 0000.0 emsm.o- 00.A 0A.mH 0~.Hmm ms
oomo.o- Amoo.o Hmmm.ou mm.H mm.om No.Amm.N AH
ssso.o: moom.o Awmm.o- 0m.OH oA.OH 0m.mwm ca
mawo.o- Amoo.o ommm.on mm.H mm.0w Hm.om0.m ms
ammm.o: Amos.o ~mmm.0: Am.m Ho.HN HA.Hmm ms
omso.ou omoo.o wAmm.ou m~.A 0A.mm m0.msw.m NH
0omm.os ssos.o mAam.o: mo.m oo.o~ mm.m0m AH
0H N 0 0H s uanOHmmmoo AH0\Eum\Nao\800 Amunv 5000 .02

wMuoEmumm NWouum aOHumHmuHou 0+0H x mm N\Hu 0> meamm

AHHN OHH<mV
N zsm mom massmmm amspmzoo

 

33

 

HH5.H: 055.0 N000.0I 50.HH 00.00 N0.000 0H
HON.H: 000.N 0000.0: H0.0 00.00 0N.000 5H
0000.0: 00.5H .0000.0: 05.0 00.0NH 00.0N5 0H
0050.0: 0N5H.0 0000.0: 05.0 00.NOH 00.0N5 0H
000.H: 000.H 0000.0: 00.5 00.00 05.055 0H
000H.0: 50H00.0 0000.0: 00.H HH.H00 5H.050.H 0H
000.H: 000.N 0000.0: 05.HH 0N.H0 00.000 NH
HHN.H: 0500.0 0000.0: 50.0 0N.50 50.H00 0H
000.H: H00.N 0000.0: 00.HH N0.H0 50.H00 0
0000.0: 00HH.0 0000.0: 05.0 0H.0NH 00.N00 0
HON0.0: 000H.0 0000.0: 05.0 00.00 H0.000 5
HHN.N: 000.N 0000.0: 00.0H 00.H0 00.000 0
0050.0: HON0.0 0000.0: 00.0 00.0NH 00.555 0
0000.0: 0H0.0 0000.0: 00.0 00.00H 00.505 0
N+0H x 0 N+0H x uamHonmmoo Aw£\8um\Nao\ewv Amusv 5600 .02
umumamumm uouum GOHumHmuHou 0H x mm N\H 0 mHQEwm

0+ u >

 

AH"0.0 oHH<mv

0 20% Mom mHADmmm 00800200

 

34

H 00.0 n ofiump 0 .oz m00a000

 

5000.0: 0000.0: 00.H 00.0NH 50.000 0H
0000.0: 5.00.0 0000.0: 00.H 0H.00H 00.000 0
0000.0: 000.0 0000.0: 00.0 00.000 00.050.H 0
0000.0: 020.0 0000.0: 00.0 H0.0: 05.000 «0
0000.0: 300.0 0000.0: 05.H 00.00H 00.000 0
N+0H N m 0H x ucmHUHmmmoo Aun\aum\mao\swv Amunv 0000 .02
Hmumamumm 0%ouu coaumHmuuou OH x mm N\H 0 mHmamm
0 0+ 0 >

 

Amusumfloa whommn : Hu0 0HH<MV
<0 200 Mon mHHDmmm 90000200

HN m4m<H

 

35

0H00.0 : 00000 0 .02 «000000

 

0000.0: 0000.0 0000.0: 00.0 00.000.0 00.000.0 00
0000.0: 0000.0 ”0000.0: 00.0 00.000.0 N0.000.0 0
0000.0: 0000.0 0000.0: 00.0 N0.000.0 00.000.0 0
0000.0: 0000.0 0000.0: 00.0 00.000.0 00.000.0 *0
0000.0: 0000.0 0000.0: 00.0 00.000.0 00.000.0 0
+0H x 0 0+0H x pamwowmmwou Au:\5um\ 80\500 A0030 0000 .02
mmumamumm uonum cOHuMHmuuou 0H m 00 «\H 0 mHmEmm
0+ 0 >

 

Amusumaoa muommn : H00 0HH<mv
00 2:0 mom mHADmmm Dmemzoo

HHN mum<H

 

36
has a mean half—life.of 342.27 hours while Run 3 with_a ratio of 8.3:1

has a computed mean of 108.47 hours and the 2:1 ratio of Run 2 produces
an average half—life of 47.56 hours. Specific activity on the other
hand was assumed to remain fairly constant with differences attribu-
table to minor variations associated with catalytic application

during material fabrication. This was substantiated by similar mean

3 3

values for specific activity of 4.33 x 10-3, 4.80x10- , and 7.24 x 10-
for Runs 1, 2, and 3 respectively.

In an effort to validate the profile of results established by
these 3 runs, a 4th run was conducted. Run 4A was a modification of
Run 3. A comparison of specific activity values derived from this
third run was conducted. The pairing combinations of samples for
Run 4A is seen in Table XIII. With the exception of sample number 4
of Run 4A, samples 3, 7, 9, and 10, each contained 2 pieces of similar
sample.material as established by specific activity. Sample 4, in this
case, contained 3 pieces of sample material and was to be used as a
further validation of this experiment.

Essentially, it was assumed that by doubling the surface area,
as was accomplished in samples 3, 7, 9, and 10, the resultant data
would show a correlating reduction in half-life as earlier displayed by
the previous 3 runs. As may be noted by the results of Run 4A, this
was hardly the case. In fact, the mean half-life for these 4 samples
(3, 7, 9, and 10) was 243.34 hours. The ratio here was 4.1:1. This
is one-half the ratio of Run 3 at 8.3:1. Yet, Run 3 had a mean
value of 108.47 hours. An investigation of 2 references on catalytic
behavior and processes indicated that the entrapment of the converted

water vapor on and around the catalyst sites may produce an

37

 

 

 

 

 

Ho.m om.om om.ooo 0H

sq.w 0N.0m 00.qu OH OH

mm.HH m~.Hq wq.qam NH

om.HH N¢.Hq 00.000 m m

m0.q mq.Noa am.qmn ma

mm.m ow.mw Hm.mmo m n

qn.m «q.mma wo.wmm ma

w0.m aH.wNH ow.~qo w

no.0 mm.o~a no.000 q q

mq.m mo.mo 00.000 «0

qo.m om.mma mm.non m m

CH N mm «\H o m mam Scum mu 0 <0 pom
m+ u > .02 waaamm .oz oaaamm

 

mu 92¢ <q mZDm mom
m 23m 20mm ZOHH¢ZHMZOU UZHMH<m

HHHN mqm<B

 

38

inhibiting effect on the activity of the material (Augustine 1965,
Rylander 1967). With_this assumption, moisture Content analysis was
performed using a vacuum oven method, described in Appendix C,

for a period of 16 hours.

The results of this analysis produced loses between 0.03% and
1.9%. This data is available in Table XIV. Following this analysis,
Run 4B was conducted to see whether this moisture loss may have had a
significant effect on the specific activity of the samples. As may
be noted by Table XV, it did not. Degradation of the specific
activity is obvious by the further reduction in the computed values.
Additional evidence is seen by sample number 4 where the ratio was
2.75:1. Both half—life and specific activity values closely parallel
those of the other 4 samples in both Runs 4A and 4B.

It was felt that at this point further investigation of catalytic
phenomena to determine a probable cause for explaining loss of
activity was beyond the scope of this project and therefore,
unwarranted.

For a better understanding of the reaction profiles of these
varied relationships, a graphical description of each run is offered
in Figures II through III. Figure II provides a composite description
of an average sample for each of the 5 runs. Figures III through VII
each describe a run by presenting linear plots of those samples
representing the high, low, and average half-lives. The vertical
axis represents recorded volumes in ul with the horizontal axis
representing time values in hours. As may be seen in Figure II, the

composite representation, the steeper the linear 310pe the lower the

39

c. : 0.0

 

OOH A3 I NBV I 00H u mmoa musumfioa N

 

 

 

 

 

 

Namm.a oommm.ma mmomm.ma mmmom.ma 00
Nmoo.H OHmNN.HH mmomu.HH «HHQH.HH a
Nmmm.0 «ooom.ma Hmaom.NH oommq.ma m
Nmmq.o ommoN.NH 0mmc~.~0 momoH.NH e
Numo.o oaom0.~0 N0©MH.NH omano.ma m
mmoq N H
ousumfioz N 3 3 Amm<Hv3 mamamm
<q 23m 20mm

<H<Q mHmNA¢z¢ mmDHHmOE

>HN mqm<fi

 

40

 

 

 

 

 

00.0 00.000.0 00.000.0 00

00.0 00.000 00.000 00 00
00.0 00.000.0 00.000.0 00

00.0 00.000 00.000 00 0

00.0 00.000.0 00.000.0 00

00.0 00.000 00.000.0 <0 0

00.0 00.000.0 00.000.0 00

00.0 00.000 00.000 00 0

00.0 00.000.0 00.000.0 00

00.0 00.000 00.000 00 0

n+0H x mm N\Hu o> cam mamamm

 

me oz< <q ZDm

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Es 02:

 

41

 

 

j:IN

 

OF 9953 m0. cam

 

«VJ.

Volume
(Vo — V)

H cam mo oMHHImams mwmum>m paw .300 .nwwm I HHH muswwm

125 02:

00.0 . £0 £0 2W 0m, 91 0.0

42

 

Vanm
(vo- v)

0— 055mm Fczm

 

rIN

(A —°AI
awnloA

T‘I’j‘

4—

3—4

2-0

1-—--I

9......

7—4

5.—

4.0

43

Run 2 Samplg 12

Run 2 Sample 17

 

 

 

 

I I I 7:1
5 ‘0 Time (hrs) 1‘5 2° 25
Figure IV — High, low, and average half-life of Run 2

44

m cam mo oMHHIMHmn owmum>m paw .BOH .swflm I.> muswfim

000 ow
_ _

00:: mEF

00
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ON

 

m0 Em

 

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T0
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1m

 

Volume
(vo— v)

45

3

<0 cam mo owfialmamn mwmuo>m paw .30H .anm I H> muswwm

a: 05:

00
_

om

 

 

A 035mm <v cam

 

IN

 

VbMWm

(vo- V)

46

no cam mo mwaalmamn mwmum>m wow .30a

.0000 : 00> 000000

 

 

 

 

 

00:00:00
OVF ON— 000 om Om ow ON
0:.II _ _ _ _ r F. 0
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[ m 295% mu cam rum e)
m V
m _
[00 w No
or o.cEmm mw cam J
1lm
N 295% mv cam lo
:I0
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mm
P

47

associated ratio. These graphical descriptions are offered as further
support of the previouSly discussed results.‘

As has been implied throughout this section, data representing
half—life and specific activity values were of primary importance for
interpretation of this study's results. This is not to say that the
accompanying data lacks significance. Quite the contrary. The
values for estimated maximum volume were required to effectively
describe the linear plots and, in conjunction with the computed B
parameter, produce the resultant values for half-life and specific
activity. Values derived for the correlation coefficients and errors
have provided a means for evaluating the accuracy of the statistical
computations. However, it is felt that further eXplanation and
development within these areas lies beyond the scope of this report.
These peripherary data are provided as supportive information
accenting the results of the primary data.

The results of this study render strong indications that
secondary or reusage of the scavenger film would be unproductive.

The specific mechanisms at work which have impaired the activity

of the material are not known. It is assumed that contamination in
one form or the other during the initial use of this material is the
cause for deterioration of its specific activity. However, as
previously mentioned, the additional investigation involving Runs

4A and 4B were designed to be supportive in nature and not of primary
concern to this project. The primary objective was to evaluate this
material as an inner package antioxidation device in support of the

protective attributes of a food package. This in itself implies a

48

one—time use as With.most hermetically sealed food containers.
Furthermore, application of such was not assumed to be by one means
alone. An inner package application may be considered to take the
form of any one design. This may include its incorporation as a
lidding closure of which various styles are available, ranging from
beverage container cap inner seals, through formed semirigid and
rigid package closures. An additional application would be that

of a package insert. The applications are limited primarily by

the package designer's imagination and the constraints of the product.
As an example of inner package application, the following illustra-
tion of design approach is offered.

Assume a typical flexible pouch fabricated of an impermeable
laminate such as Surlyn/foil/Surlyn. Total package volume is 89.43 cc.
It is estimated that 10% of the volume remains as headspace after
product fill. Within this pouch, freeze dried beef hash, an oxygen
sensitive product, will be packaged. This food product is packaged
during a conventional form-fill—sealing process. Incorporated in
the filling and sealing operation is the gas flushing phase which
introduces in a flushing manner, the prescribed mixture of 8% H2 and
92% N2 gas. Residual oxygen in the headspace is estimated to be 2%.
The 02 scavenger material previously attached inside or inserted into
the pouch is of 20 cm2 surface area. The derived oxygen uptake rate
found for the specific activity was 5.46 x 10"3 grams of 02/cm2/atms/hr.
Applying the above values in Equation 7 or more specifically:

P = P' e-SamT/vaAfxt)
2 O2

49

where:
Sa = 5.46x10‘3
R = 82.06 (cc-atm/OK—mole)
T = 2980K
M = 32g/mole
V = 8.943 cc (headspace vol)
Af = 20 cm2 (film surface area)
P6 = 2.344x10'4 grams 02
2
From Equation 6, B = 9.33 and from Equation 7:
P02 = 2.344 x lOml‘e'g'33t

Applying Equation 9, t1/2 = 0.074 hours.
Therefore, at t1/2’ P02 = 1.172 x 10-4.
This is verified alternately by P6 /2 which defines t1/2.

Table XVI offers a range of dita of which the reduction of
headspace oxygen over time is represented graphically in Figure VIII.
Permeability is a function of many variables as may be seen in the
above example. The imbalance of internal and external partial gas
pressures will seek equalibrium. The time involved is primarily
associated with the generic properties of the film such as the rate
at which the gas will dissolve into the surface of the material,
diffuse through, and evolve into the reduced atmosphere. The deter—
mined rate for catalytic activity is based upon this phenomenon of

gas diffusion with the rate of diffusion being somewhat proportional

to the partial pressure of the gas.

50

 

00.0 0:000000.0 0:000000.0 00.0 0000.0 000000
00.0 0:000000.0 0:0000000.0 00.0 0000.0 000
00.0 0:000000.0 0:000000.0 00.0 0000.0 000
00.0 0:000000.0 :0000000.0 00.0 000.0 000
00.0 0:000000.0 0:000000.0 00.0 000.0 000
00.0 0:000000.0 0:000000.0 00.0 000.0 000
00.0 0:000000.0 0:000000.0 00.00 000.0 000
00.0 0:000000.0 0:000000.0 00.00 000.0 00\0
00.0 0:000000.0 0:0000000.0 00.00 000.0 00000
0 00 00.0 .a0z .000 00

 

Mom <H<Q QMHDmZOU

H>x mam<H

mZHH Mm>o ZOHHUDQmm zmuwxo m0<mmn<mm

 

51

@800 um>o comxxo momemvmos mo dowuoswom I HHH> mudwwm

?::VoFFH
VP N— or
0 0 . _

 

 

 

Headspace Oxygen (%)

52

 

Sa

Specific Activity (g/cm2/atm/hr)
Area (cmz)
Straight line parameter (y intercept)
Straight line parameter (slope)
Volume (cc)

Pressure (1 atm)

Partial pressure of 02

Temperature (K0)

Time (hrs)

Molecular wt (32g)

Gas constant (82.06 ml-atm/OK-mole)

Mass of gas

SUMMARY

The objectives of this investigation were to examine American
Can's oxygen scavenger laminate film as an inner package anti-
oxidant device rather than its employment as the complete primary
package. This laminate material provides a means by which residual
headspace oxygen can be consumed through a catalytic hydrogenation
within the film structure.

The literature survey revealed investigations which were con-
ducted on oxygen scavenger films, concluding that their conceptual
implementation as the primary package was quite significant in
extending the shelf-life periods of oxygen sensitive food products.

The methodology for this investigation was of a three phase
design requiring: 1) Initial preparation of samples, equipment,
and apparatus; 2) Submitting samples to the system measuring this
oxygen uptake; and, 3) Applying the derived data to a hypothetical
package design. The primary instrument for data gathering was a
gas differential respirometer designed to measure changes in volume
through changes in pressure. Samples were submitted to a closed
system whereby their activity of headspace oxygen consumption was

readily measured. Due to the limited measuring capacity of the

53

54

instrument, a computer program was incorporated to estimate total
volume uptake from which the specific activity of the sample material
was calculated.

Five different experiments were run, three of which involved
different ratios of headspace volume (30 cc) to film surface area,
with the remaining two of the same ratios and material yet under
different conditions.

The first three runs of ratios 2:1, 8.3:1, and 18.6:1 showed
a progressive increase in half—life period or that period required
to consume one—half the original volume of headspace oxygen.

The remaining two runs, 4A and 4B, were designed to support
the results of the previous findings. Run 4A incorporated a
selective doubling of samples of similar specific activity used and
found in Run 3. ‘Presumably by doubling the sample material (surface
area) a one-half reduction in half-life periods should be produced.
Such.was not the case. The evidence indicates that some inhibition
of film specific activity had occurred. Run 4B was conducted under
the assumption that the converted water vapor might be causing a
blockage of the supported catalyst sites and thus, inhibiting the
material's specific activity. Prior to Run 4B, moisture content
analysis was performed as a design to establish the amount of moisture
formed and held by the material and, secondly, provide a dehydrating
effect and thereby reactivating the activity of the film. The

results of Run 4B showed a further regression of specific activity.

CONCLUSIONS

From this investigation it is concluded that:

Maraflex 7—F Oxygen Scavenger film may be effectively used
as an antioxidative inner package device.

Increasing the ratio of headspace volume to film surface area
increases the half—life period of oxygen consumption.

Inhibition of film specific activity develops through its
use.

Reuse of this material (everything held constant) will
produce less effect on oxygen consumption than its previous

effect.

The linear logarithmic relationship of oxygen uptake data is
supported by the mathematical model.

55

REFERENCES

REFERENCES

BOOks

Augustine, Robert L., Catalytic Hydrogenation, Marcel Dekker, Inc.,
1965 — New York, Chapter 3, pp. 36—39

Desrosier, Norman, W., The Technology g§_Food Preservation, AVI

Publishing Company, Inc., Westport, Conn., 3rd ed., 1970.
pp. 301-302 & 31-33

 

Rylander, Paul N., Catalytic Hydrogenation OVer Platinum Metals,
Academic Press Inc., 1967 - New York, Chapter 1, pp. 16-17

Thomas, Charles L., Catalytic Processes and Proven Catalysts,
Academic Press, New York, 1970, pp. 118—119

Umbreit, W. W., R. H. Burres, and J. F. Stauffer, Manometric

Techniques, Burgess Publishing Co., Minneapolis, Minn., 4th ed.,
1964

 

Wilde, Douglass J., Optimum Seeking Methods, Prentice-Hall, Inc.,
Englewood Cliffs, N.J., 1964, pp. 10-52

Journals

Abbott, J., R. Waite, and J. R. Hearne,; "Gas Packaging Milk Powder
With a Mixture of Nitrogen and Hydrogen in the Presence of
Palladium Catalyst," Journal gf_Dairy Research, 28:285, 1961.

 

Berlin, E., and M. H. Pallansch, "Influence of Drying Methods on
Density and Porosity of Milk Powder Granules," Journal g£_Dairy
Science, 46:8, 1963.

Karel, Marcus, "Packaging Protection for Oxygen-Sensitive Products."
Food Technology, Aug. '74, pp. 51-65.

King, J., "Catalytic Removal of Oxygen from Food Containers,"
Food Manufacturing, 30:441, 1955.

56

57

REFERENCES (Cont'd)

Kurtz, F. E., M. J. Pallansch, and A. Tamsma, "Effect of Oxygen

Removal Technique.on Flavor Stability of Low—Heat Foam Spray
Dried Whole Milk," Journal o£_Dairy Science, 50:10, 1967.

 

Kurtz, G. W., and Y. Yonezawa, "Institute Food, Tech. 17th Annual
Meeting, Pittsburgh," Food Technology, 11:4, page 16, 1957.

 

Mucha, T. J., M. J. Pallansch, W. I. Patterson and A. Tamsma,
"Factors Related to the Flavor Stability of Foam-Dried Whole
Milk," Journal o£_Dairy Science, 44:9, 1961.

 

"Oxygen scavenger package stops oxidation, extends shelf-life,"
Food Processing, Sept. '73.

 

Peters, James W., "packaging film improves shelf-life, protects
flavor by removing oxygen, halting oxidative changes,"
Food Product Development, Apr. '74, pp. 67068.

Zimmerman, Paul L., Lyle J. Ernst, and William F. Ossian,
"Scavenger Pouch Protects Oxygen—Sensitive Foods," Food
Technology, Aug. '74, pp. 63-65.

 

PRESENTATION

Kuhn, P. E., K. F. Weinke, and P. L. Zimmerman, "Oxygen Scavenging
System for Flexible Packaging of Whole Dry Milk," Ninth Milk
Concentrates Conference, Sept. 15, 1970.

APPENDICES

APPENDIX A

Appendix A

Headspace Oxygen Analysis Procedure

The following procedure describes the methodology, apparatus,

and technique used in the quantitative determination of residual

headspace oxygen of a package.

58

APPENDIX A

Headspace Oxygen

I. GENERAL
The amount of oxygen remaining in the headspace of packages

containing food products is very critical. The amount of oxygen
present has a definite influence on shelf—life and product quality.
The amount of oxygen in the headspace can be quantitated by gas
chromatographic techniques. The percentage of oxygen is quantitated
by ascertaining the peak areas of the different gases present in the
headspace.
II. APPARATUS

1. Gas chromatograph (5A molecular sieve column)

2. Gas chromatograph recorder

3. Integrator

4. Helium carrier gas and regulator

5. Standard gas

6. Gas-tight sampling syringe

7. Headspace plunger

8. Vacuum gauge

9. Vacuum source

10. Headspace gas sample extracting apparatus

III. PROCEDURE
A. Analysis of Standard Gas

1. Standard gas is analyzed at the beginning and the end of a
series of analyses which indicate analytical and

59

60

APPENDIX A (Cont'd) —

III.

A.

(Cont'd)
l. (cont'd)
instrumentation performance. This is accomplished simply by
injecting a standard of air into the chromatograph and thereby
verifying the satisfactual operation of the chromatograph,
integrator, and recorder.
2. Operating condition of gas chromatograph and recorder.
i. Column temperature 150°C (302°F).
ii. Helium carrier gas flow rate approximately 30 cc/min.
Analysis of Headspace Gas

1.

Place food can under the headspace plunger (5) (see Figure l)
and secure with wing nut level bar to seal plunger rubber
septum to the can. Make sure needle is in the retracted
position.

Insure that all valves are in the closed position.

Turn on vacuum source.

Insert needle through rubber septum until contact with metal
lid is made.

Open valves (1) and (2), and evacuate the whole system to
maximum allowable limits available.

Close valve (1) for 15 seconds and check for leaks. (Drop
in vacuum gauge reading is an indication of a leak).

Open valve (3) until vacuum is lost, then close valve (3).

61

APPENDIX A (Cont'd) 0

III.

B.

(Cont'd) —

8. Open valve (1) and restore vacuum.
9. Repeat steps 9 and 10 once.

10. Close valve (1).

11. Open valve (3) and closely monitor the loss of vacuum until
it reaches "0" then close valve (3). Because the flushing
gas is under positive pressure, one should minimize an
overload of positive pressure upon reaching equilibrium.

12. Inject the needle through the lid surface until a vacuum
is noted on the gauge. Do not inject excessively for
fear of incorporating product material in the needle
orifice.

13. Equalize pressure by opening valve (3) until "0" vacuum is
noted. (Allow same positive pressure to exist).

14. Close valve (2).

15. Open valve (1) until full vacuum is registered.

16. Close valve (1).

l7. Allow 1 to 2 minutes for the stabilization of partial
pressures.

18. Open valve (2). The capacity of the system will allow
headspace gas to be drawn into the sample removal area.

19. Close valve (2).

20. Allow 1 to 2 minutes for gas stabilization.

62

APPENDIX A (Cont'd) —
B. (Cont'd) —
21. With a gas tight syringe, remove gas sample from septum
(4) and inject into chromatograph.
22. Results are recorded on a strip chart recorder.
C. Calculation
Computation for 02 concentration derived from integrated data
will be the following:
N + 02 = X

2

02/x Y

(Y) (0.1644) Net Oxygen Concentration

of the Headspace
IV. REFERENCES
1. Whirlpool Corporation Document No. 24—00333, "Food

Can Headspace Oxygen Analysis Procedure."

63

FIGURE 1
Diagrammatic Sketch.of Sampling Device

and Gas Chromatograph

 

 

 

 

 

 

 

 

 

He 2 5 1
1 4 Int

1
who Can Rec.

 

 

 

 

 

 

 

 

Vacuum on—off valve (Hoke—Tomco Solenoid)
System on—off valve (Hoke—Homco Solenoid)
He gas flushing on—off valve (Whitney)
Sample gas removal septum port

Headspace gas sampling device (Hamilton)

C. C. sample injection septum port

APPENDIX B

64

FIGURE 2
Headspace Gas Sample Flow

and Reporting

Receive sample
via TPS from c; Headspace gas
Food Depot analysis (Packaging Engineer,
T.I.)

 

Headspace gas report preparation
(Packaging Engineer,
T.I.)

Report approval
(Mgr., Food Sciences,

T.I.)

Report approval
(Chief, Food and Nutrition,
DB3)

File Report with Data Package

(Mgr. Food Depot,
T.I.)

Appendix B

Computer Program

This program was generated by Dr. Wayne Clifford of the School
of Packaging, Michigan State University. The program utilizes
mathematical and statistical models for the conversion of raw
data into applicable information. Critical values establishing
the initial volume of headspace oxygen, A and B Parameters of the
linear models, and correlation coefficients along with the error
for variance, were computed from raw data of incremental time (hrs)

and volume of headspace oxygen consumed (ul).

65

66

APPENDIX B

COMPUTER PROGRAM

COMMON T(SO), X(SO), Y(50), QTT, ST, SGN, N
90 READ(5,200) N, ERROR
IF (N.LE.O) CALL EXIT
WRITE(6,205) N, ERROR
READ(5,210) (X(I), T(I), I=1,N)
IF(N.LT.0.0) GO TO 1000
WRITE(6,215) (x(I), T(I), I=1,N)
SGN=FSN(X(N) - X(l))
DEL=5.0*(X(N-1) - X(N))
ST=0.0
STT=0.0
DO 100 I=1,N
ST=ST + T(I)
STT=STT + T(I) * T(I)

100 CONTINUE
QTT=N*STT - ST*ST
CALL LLSQ(DEL,NCHG,SS,))
DELX=O.6*DEL
CALL LLSQ(DELX,NCHG,SSX,O)
IF(SSX - ss) 120, 120, 140

120 DMAX=DEL

125 SSM=SSX
DELX=0.3*DELX
CALL LLSZ(DELX,NCHG,SSX,O)
IF(SSX — SSM) 125, 125, 130

130 DMIN=DELX
GO To 160

140 DMIN=DELX

145 SSM=SS
DEL=3.0*DEL
CALL LLSZ(DEL,NCHG,SS,O)

IF(SS - SSM) 145, 145, 150

150 DMAX=DEL

160 DELL=DMIN + 0.618*(DMAX - DMIN)
CALL LLSQ(DELL,NCHG,SSL,O)

170 IF(ABS(DMAX - DMIN).LT.ERROR) GO TO 190
WRITE (6,330) DMIN,DMAX
IF(ABS(DMIN—DELL).GT.ABS(DMAX—DELL)) GO TO 180
DEL=DMIN + 0.618*(DMAX - DMIN)
CALL LLSZ(DEL,NCHG,SS,O)
IF(SS.GT.SSL) GO TO 175
DMIN=DELL
DELL=DEL
SSL=SS
GO TO 170

175 DMAX=DEL
GO TO 170

67

APPENDIX B (Cont'd)

180

185

190

200
205
210
215
330
1000

220
90

100

DEL=DMIN + 0.382*(DMAX - DMIN)
CALL LLSQCDEL,NCHG,SS,O)
IF(SS.GT.SSL) GO TO 185
DMAX=DELL

DELL=DEL

SSL=SS

GO TO 170

DMIN=DEL

GO TO 170

CALL LLSQ(DELL,NCHG,SS,10)

GO To 90

FORMAT(13,E10.5)
FORMAT(1H1,5X,18,13H = N, ERROR = ,E15.5)
FORMAT(2F10.5)
FORMAT(20X,2F15.8)
FORMAT(38X,2HGS,2F14.7)

STOP

END

SUBROUTINE LLSQ(DEL,NCHG,HQQ,KPRT)
COMMON T(SO), X(SO), Y(50), QTT,ST,SGN,N
DIMENSION E(50)

DATA KQQ / 0 /

XZ=X(N) - DEL

KQQ=KQQ + l

IF(KQQ,LE.50) GO T0 90

WRITE(6,220)

KPRT=5

FORMAT(10X,3OHABORT, TOO MANY CALLS TO LLSQ )
SY=0.0

SYY=0.0

SYT=0.0

DO 100 I=l,N

Y(I)=ALPG((XZ - X(I))*SGN)

SY=SY + Y(I)

SYY=SYY + Y(I)*Y(I)

SYT=SYT + Y(I)*T(I)

CONTINUE

B=(N*SYT - SY*ST)/QTT

A=(SY - B*ST)/N

R=B*SQRT(QTT/(N*SYY - SY*SY))

NCHG=0

XQ=A + B*T(1)

E(L)=Y(L) - XQ

SS=E(1)*E(1)

I=l

IF(KPRT,GT,O) WRITE(6,210)T(I),X(I),Y(I),XQ,E(I)
SL=FSN(E(1))

68

APPENDIX B (Cont'd)

210

130

200

100

120

FORMAT(1X,5E14.6)

DO 130 I=2,N

XQ=A + B*T(I)

E(I)=Y(I) — XQ ,
IF(KPRT.GT.0) WRITE(6,210)T(I),X(I),Y(I),XQ,E(I)
SS=SS + E(I)*E(I)

SN=FSN(E(I))

IF(SN.EQ.SL) GO TO 130

NCHG=NCHG + 1

IF(NCHG,EQ.1) K101

K2=I

SL=SN

CONTINUE

K=0.5*(K1+k2)

NCHG=NCHG*FSN(E(K))
NCHG=NCHG*FSN(E(K))

WRITE(6,200) XZ,DEL,A,B,R,NCHG,SS
FORMAT(5X,4E16.9,/,E16.9,15,El6.9)
IF(KPRT.EQ.10) KQQ=0

IF(KQQ.GT.60) CALL EXIT

RQQ=L.) — ABS(R)

RETURN

END

FUNCTION FSN(X)
IF(X) 100, 120, 120
FSN=—l.0

RETURN

FSN=1.0

RETURN

END

APPENDIX C

Appendix C

Moisture Content Analysis Procedure

The following procedure is an excert from Methods of_Analysis,
11th ed. (1970), AOAC. This procedure was employed as a guide
for moisture content determination applied here. Essentially,
under controlled conditions, the conditioned sample dish is
weighed, followed by sample introduction. The dish with sample
is weighed after which it is subjected to a controlled vacuum-oven
drying period, succeeded by reweighing and moisture loss

computation.

69

70

APPENDIX C

3.0 ANALYTICAL PROCEDURES

3.1 MOISTURE — A Vacuum Oven Method

I. GENERAL

The determination of the moisture content of a food is not only
an important proximate analysis, but also provides a means for
converting all other nutrient composition on an absolute dry weight
basis. This method is based on the removal of water from the food
solids by drying in a vacuum oven heated at 70 il2°C to a constant
weight. The resulting loss of weight of the sample is a measure of
the amount of water in the sample.

Although the moisture determination is the most simple of
analytical operations, it is not free from problems when an accurate
analysis is desired. To completely separate all the water from the
product without simultaneously causing decomposition of the product is
difficult. Errors may be introduced by loss of some volatile com-
ponents and during weighing a low moisture—content food such as dried
and freeze-dried foods through a small weight change and water
resorption from the atmosphere. In fruits, vegetables and similar
products, and in products containing syrup, difficulties in expelling
water arise from hardening of the surface causing occlusion of water.
A thin layer of the product evenly Spread in the evaporating dish

facilitates the release of water from the product.

71

APPENDIX C (Cont'd)

II. APPARATUS
1. Balance, analytical

2. Metal dish, flat bottom, with tight fitting slip in cover,
5 cm to 8 cm in diameter

3. Oven, vacuum
4. Dessicator

5. Tong

III. PROCEDURE

A. Sample Preparation

All dehydrated and freeze-dried products should be comminuted
finely enough to pass a 20 mesh sieve as the coarser particles do
not release water readily. All liquid and semi-liquid samples should
be well blended before proceeding for moisture analysis.

B. Sample Size

Sample size depends on the solid content of the food. In
general, weigh an amount of sample that would give approximately
2 g of the dry residue.

C. Oven Drying of Samples
1. Weigh the moisture dish along with its cover, which has
been previously dried at 100: 5°C and kept in a dessicator.
Do not handle the dish with fingers.
2. Transfer the sample to the dish and spread it evenly at the
bottom of the dish. In general, take about 2 g for dried

and freeze-dried sample, 5-10 g for semidry and wet products,

10 g for fresh or canned fruits and vegetables. For liquids
containing low amounts of solids, use 25-50 g sample.

72

APPENDIX C (Cont'd)

III.

IV.

(Cont'd)

3. Partially uncover the dish and dry the sample at 70: 2°C
under pressure not to exceed 100 Torr for a period of 5 hours.
For meats and meat products, use a drying temperature of
95° to 1000 for 5 hours.

4. During drying admit a slow current of air into the oven
(about 2 bubbles per second) which has been dried by passing
through concentrated sulfuric acid.

5. After a 5 hour druing period is over, cover the dish tightly
and transfer it to a dessicator to cool to room temperature.

6. Weigh the dish to determine the loss in moisture in the
food sample.

7. Repeat Steps 3 - 6 for a 30 minute period of drying.

Compare results to the weight previously obtained.

Calculation

Water content, g/100 g =(W2 % W) .100

 

(W1 - W)
Where
W' = weight of dish with cover, g
W1 = weight of dish with cover + sample
W2 = weight of dish with cover + residue
REFERENCES

AOAC. Methods of Analysis, 11th Edition (1970) p. 211

 

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