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This is to certify that the

thesis entitled

THE INFLUENCE OF SELECTED BARRIERS AND
OXYGEN ABSORBERS 0N PRODUCT QUALITY

presented by

CHIHIRO SAKAMAKI

has been accepted towards fulfillment
of the requirements for

M . 5. degree in PACKAGING

flog/W

Bruce R. ngteL,Ph.D.

Major professor

 

 

 

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THE INFLUENCE OF SELECTED BARRIERS AND OXYGEN
ABSORBERS ON PRODUCT STABILITY

By

Chihiro Sakamaki

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements

for the degree of

MASTER OF SCIENCE

School of Packaging
l986

ABSTRACT

THE INFLUENCE OF SELECTED BARRIERS AND OXYGEN
ABSORBERS ON PRODUCT STABILITY

By

Chihiro Sakamaki

Packages made from polyethylene (PE) and PVDC-coated
polypropylene (PP)/polyethylene were filled with oat cereal
and flushed with a known concentration of oxygen. Some
were packed with an oxygen absorber. The oxygen absorber J//
is packed in a small pouch made of low barrier material.
Lipid oxidation was monitored monthly throughout the five
month storage period using a modified TBA method. Head
space oxygen was also determined. In general, the oxygen
absorber retarded or delayed lipid oxidation in the oat
product during storage. The effectiveness of the absorber
was reduced over the length of the storage period when
product was packed in the low barrier material (PE) and
stored at high humidity and temperature (65°C). There was
a five-fold increase in the TBA index between product in
the PE pouch without absorbers and product in the PVDC-
coated PP/PE package with absorber at 4lOC. Loss of product
quality, as measured by sensory evaluation, was in general
agreement with the TBA index and amount of 02 consumed by

the oat cereal.

ACKNOWLEDGMENTS

I present this thesis to my advisors, Dr. Bruce Harte,
Dr. Ian Gray and Dr. Jack Giacin, who encouraged and lead
me in this accomplishment with great generosity. I give
special thanks to these advisors, School staff, and graduate
students in Dr. Gray's laboratory. I also have great
appreciation for the long-time dedication of my wife,

Carolyn, who is a devoted scholar, noble and loves me.

ii

TABLE OF CONTENTS

LIST OF TABLES
LIST OF FIGURES.
INTRODUCTION .
LITERATURE REVIEW.
Oxygen Absorbers
Oat Lipids . .
TBA Test for Evaluating Lipid Oxidation.
METHODOLOGY.
Sample Preparation
Sample Storage . .
Index for Lipid Oxidation.
Modified TBA Test.
Residual Oxygen Concentration of the Package
Sensory Evaluation . . .
Oxygen Permeability of the Sample Films. . .
Scavenging Ability of the Oxygen Absorber. .
RESULTS AND DISCUSSION

Storage Study. . .
Absorbing Ability of the OA.

SUMMARY.
APPENDICES
BIBLIOGRAPHY

111'

Page
iv

vi

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111
114
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Table

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10

11

LIST OF TABLES

Fatty acid composition of oats (Hammond, 1983).

Experimental conditions

Change in the M-TBA index for M-TBA index
Concentration change of headspace 02.
Results of the sensory evaluation

Average 02 consumption.

ANOVA table for a p x q factorial experiment
with r replicates .

ANOVA for the date of sampling x packaged
condition (410C, 40% RH PVDC coated PP/PE, 21%
initial 02 concentration, with 02 absorber vs
410C, 40% RH, PVDC coated PP/PE, 1% initial

02 concentration no 02 absorber). . . .

ANOVA for the date of sampling x packaged
condition (41°C, 40% RH PVDC coated PP/PE, 5%
initial 02 concentration, no 02 absorber vs

41°C, 40% RH, PVDC coated PP/PE, 1% initial 02

concentration, no 02 absorber).

ANOVA for the date of sampling x packaged
condition (41°C, 40% RH PVDC coated PP/PE, 21%
initial 02 concentration, no 02 absorber vs

41°C, 40% RH, PVDC coated PP/PE, 5% initial 02

concentration, no 02 absorber).

ANOVA for the date of sampling x packaged
condition (41°C, 40% RH PVDC coated PP/PE, 21%
initial 02 concentration, with and without 02
absorber)

iv

Page

20
29
34
32
77

30

52

54

55

81

Table
12

13

14

15

16
17

ANOVA for theddate of sampling x packaged
condition (41 C, 40% RH PE, 21% initial 02
concentration, with and without~02 absorber.

ANOVA for the date of sampling x packaged
condition (41°C, 40% RH, PVDC coated PP/PE, 21%
initial 02 concentration, light exposure, with
and without 02 absorber) . . . . . . .

ANOVA for the date of sampling x packaged
condition (41°C, 80% RH, PVDC coated PP/PE, 21%
initial 02 concentration, with and without 02
absorber . .

ANOVA for the date of sampling x packaged
condition (21°C, 45% RH, PVDC coated PP/PE, 21%
initial 02 concentration, with and without 02
absorber). . . . . .

02 permeability of the sample films.

Absorbing ability of the 02 absorber .

Page

31

91

86

106
42
39

Figure

10

LIST OF FIGURES

Formation of TBA pigment.

Package modification for high RH (41°C, 80%
RH . . . . . . . . . . . .

M- TBA index as a function of time for oat
cereal packaged in PE, and stored at 41°C, 40%
RH, under 21% initial headspace 02. .

M- TBA index as a function of time for oat
cereal packaged in PVDC coated PP/PE and stored
at4l°C,40%RH

M-TBA index as a function of time for oat
cereal packaged under 21% initial headspace 02
with 02 absorber and stored at 410C, 40% RH

M-TBA index as a function of time for oat
cereal packaged in PVDC coated PP/PE under 21%
initial headspace 02 and stored at 41°C .

M- TBA index as a function of time for oat
cereal packaged in PVDC coated PP/PE under 21%
initial headspace 02 and stored at 21°C, 45%
RH. . . . . . . . . . .

M- TBA index as a function of time for oat
cereal packaged in PVDC coated PP/PE under 21%
initial headspace 02. and stored at 41° C, 40%
RH. . . . . . . . . . .

W TBA index as a function of time for oat
cereal packaged in PVDC coated PP/PE under 21%
initial headspace 02. and stored at 65°C, 45%
RH. . . . . . . . . . .

M- TBA index as a function of time for cat

cereal packaged in PVDC coated PP/PE with 02.
absorber, 21% initial headspace 02. . . .

vi

Page
11

18

28

57

8O

85

103

105

108

110

Figure Page

11 M- TBA index as a function of time for oat
cereal packaged in PVDC coated PP/PE and
stored at 41 , 40% RH, 21% initial headspace 89
02.. . . . . . . . . . . . . . . . . 1

12 Headspace 02 concentration as a function of

time for oat cereal packaged in PE under 21%
initial headspace O2. and stored at 41° C, 40% 3
RH. . . . . . . . . . . . . . . . 6

13 Headspace 02 concentration as a function of
time for oat cereal packaged in PVDC coated
PP/PE and stored at 41°C, and 40% RH. . . . . . 45

14 Headspace 02 concentration as a function of
time for oat cereal packaged with O2 absorber
and stored at 41°C, 40% RH, 21% initial
headspace 02. . . . . . . . . . . . . . . . 48

15 Headspace 02 concentration as a function of
time for oat cereal packaged in PVDC coated
PP/PE and stored at 41°C. . . . . . . . . . . . 51

16 Headspace 02 concentration as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 21°C, 45% RH. . . . . . . . 93

17 Headspace 02 concentration as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 65° C, 45% RH. . . . . . . . 95

18 Headspace 02 concentration as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored either at 40 or 45% RH, 21%
initial headspace 02.. . . . . . . . . . . . 97

19 O2 consumed and M- TBA index as a function of
t1me for oat cerea1 packaged in PE and stored
at 41°C, 40% RH, 21% initial headspace 02 . . . 64

20 02 consumed and M- TBA index as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 41°C, 40% RH, 21% initial
headspace 02.. . . . . . . . . . . . . . 66

21 02 consumed and M- TBA index as a function of

time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 41°C, 40% RH. . . . . . . . 68

vii

Figure Page

22 O2 consumed and M-TBA index as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 41°C, 80% RH, 21% initial
headspace 02. . . . . . . . . . . . . . . . . . 7O

23 02 consumed and M- TBA index as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 21° C, 45% RH, 21% initial
headspace 02.. . . . . . . . . . . . . . . . . 72

24 O2 consumed and M- TBA index as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 65°C, 45% RH, 21% initia1
headspace 02.. . . . . . . . . . . . . 74

25 O consumed and M- TBA index as a function of
t1me for oat cereal packaged in PVDC coated
PP/PE and stored under light at 41°C, 40% RH,
21% initial headspace 02.. . . . . . . . . . . 76

26 02 permeability of PE and PVDC coated PP/PE as
a function of temperature . . . . 41

27 Average 02 consumption rate (AOR, 0-20 days) as
a function of temperature for oat cerea1
packaged in PVDC coated PP/PE and stored at
medium humidity in the dark, 21% initial
headspace 02. . . . . . . . . . . . . . . . . . 100

28 Absorbing ability of the O2 absorber as a
function of weight at 21°C. . . . . . . . . . . 38

viii

INTRODUCTION

The use of preservatives in food products has allowed
the deve10pment of many food items which can be stored for
long times with lower risk of food poisoning. Recently,
low salt, low sugar and use of less food preservatives have
been demanded in processed foods, in view of the concern
for human health. These treatments usually shorten the
product's shelf life. Therefore in order to lengthen shelf
life, manufacturing processes, packaging, and the distribu-
tion system are optimized. Many products now require
inert gas atmosphere packaging to attain the desired shelf
life when stored at ambient conditions. Sophisticated
methods of obtaining inert gas atmospheres in packages,
called a gas flush system, have been developed. The
residual oxygen level of these processes is usually reduced
to 1-2% with most commercial packaging systems. Still,
some products such as whole dried milk become unacceptable
from a flavor standpoint after 3-6 months storage in these
levels of oxygen at ambient conditions.

Recently, pouched type oxygen absorbers (OA) have been
developed and commercialized in Japan. 0A are packed in

small pouches made of low barrier materials. The agents

inside the pouch function by absorbing oxygen. The powdered
oxygen absorber and food are packed together in a container
of high barrier material. The objective of this study was
to evaluate the storage stability of flaked, oat cereal
product packed in different materials, with and without the
oxygen absorber. The oat cereal is known to be very
susceptible to lipid oxidation. The influence of initial
oxygen concentration (1, 5, and 21%), storage temperature
(21, 41, and 65°C), relative humidity and light exposure on

product quality was evaluated.

LITERATURE REVIEW

Oxygen Absorbers (0A)

Mucha et a1. (1961) showed that extremely low oxygen
concentrations are necessary to prevent oxidative flavors
in reconstituted foam-spray-dried whole milk. Flavor
evaluation confirmed differences in products stored in 0.1%,
1.0%, and 20% oxygen concentration. Berlin and Pallansch
(1963) reported that to reduce the oxygen level trapped
inside dry milk particles to less than 0.1%, it was necessary
to use an efficient gas flush system with a scavenging
system to absorb any oxygen entrapped in the product or
permeating through the packaging material.

Maude et al. (1925) developed a free oxygep absorber
which consisted or iron powder, ferrous sulfate and a
hygroscopic substance in order to assure the safety of-
electric transformers against explosion in the United
Kingdom (UK). The first application of 0A for preserving
the quality of a dry food was reported by Isherwood (1943)
in the UK. Brinkmann and Schlebush (1953) introduced an 0A
in West Germany which consisted of active carbon and metal.

In the United States (USA), Loo et a1. (1958) developed an

oxygen absorber composed of sulfate and sulfite. A gas
replacement system, where both a gas flush and a catalyst
were employed, was developed by American Can Co. in the
late 1960's, this was known as the Palladium Catalyzed
Oxygen Scavenging System. With this method, the package
head space was first flushed using a gas mixture (92%
nitrogen, 8% hydrogen) and the package was sealed. The
palladium catalyst was laminated between the film layers.
Hydrogen in the head space reacted with residual oxygen to
form water. Palladium catalyzed the oxygen scavenging
reaction in the presence of hydrogen as follows:

Pd

Several studies using this catalyst impregnated film (PET/
PVDC/Polyvinyl alcohol/PE/catalyst/PE or PET/foil/ionomer
catalyst/ionomer) were conducted in the early 1970's. Kuhn
et a1. (1970) concluded that such a scavenger system
containing polyvinyl alcohol as the principal gas barrier
medium is very effective in achieving and maintaining very
low residual oxygen concentrations in packages containing
foam-spray-dried milk. Kuhn et a1. (1970) also described
three possible scavenging systems. The first one used a
separate container employed as an oxygen scavenging device
for head space oxygen, placed in the head space of a packaged

product. The second one was achieved by using glucose

oxidase and glucose. Mixtures of glucose oxidase, glucose
and water were packaged in low barrier materials and placed
in the packaged food. The scavenging reaction could absorb
2% of the oxygen in the package. The scavenging reaction
occurred only if ample water was present. The third one
was the oxygen scavenger impregnated film system as
mentioned before.

Zimmerman et a1. (1974) changed the structure of the
oxygen scavenger impregnated film, to PE/foil/ionomer/
catalyst/ionomer in order to prevent seal failure and also
improve the reliability of the scavenging activity. They
performed a 1—year storage study on 4 ounce gas flushed
scavenger packs containing whole milk powder, at four
storage conditions (45°F/90% RH, 73°F/50% RH, lOO°F/20% RH
and lOOOF/9O% RH). There was no flavor change during
storage for one year at any condition except 100°F. In

this study, Zimmerman et a1. made observations for

6 months. They pointed out that cereal products and citrus
crystals can be effectively packaged using the same tech-
nique. In spite of such results, these systems were not
commercially successful. The most critical problem was the
presence of hydrogen gas in the package and concern for
product safety.

In Japan an inorganic oxygen absorber based on a
dithionite (sodium hyposulphite and hydrosulphite) was
developed by Fujishima (1977). It was claimed that sulfur

dioxide ($02) was formed and trapped in the food product
during the reaction. Inorganic materials such as iron,
and organic materials called reductons were chosen for the
deoxidizer. Saito (1979) conducted storage studies with
vegetable oil, dry instant noodles and fried beans packed
with GA. He measured acid value (AV) and peroxide value
(PV) as indexes of oxidation. He observed an increase of
PV packed without an oxygen absorber, little change with
the oxygen absorber (0A) and little change in AV for
samples packed with and without an OA during 2 months of
storage. Saito concluded that oxygen absorbers can effec-
tively reduce the oxidative degradation of the processed
food. Uematsu and Someya (1978) researched the effect of
oxygen concentration and exposure to light on the lipid
oxidation of fried rice cake and buttered peanuts. During
3 months storage at 30°C, they found that a nitrogen gas
(N2) flush of the fried rice cake (97% exchanging efficiency)
did not prevent oxidation. The use of an ultraviolet
absorbing film, a foil laminated film and a high barrier
film with an OA did reduce oxidation of the fried rice
cake. For the buttered peanuts in two conditions, a N2
gas flush and use of an OA did effectively prevent oxidation.
For the fried rice cake, preventing exposure to light was
effective. Their results indicated that extent of lipid
oxidation depends on each products' characteristics,

however, eliminating oxygen is always effective. Oxidation

cannot occur in the absence of oxygen which is recognized
as a physical requirement in the mathematical model for

oxidation of potato chips by Quast et a1. (1972).

Oat Lipids

 

Oat products are known to be very susceptible to lipid
oxidation. In general, the lipid portion, extracted with
nonpolar solvent, ranges from 2.0 to 11.0% (Hammond, 1983).
Pokorny et al. (1961) first applied gas-liquid chromatography
(GLC) to the analysis of oat lipids in order to classify the
fatty acids. Lindberg et a1. (1964) reported the first GLC
results that gave resolution of all the major oat fatty
acids. Since then GLC has been used in many studies
relating to fatty acid composition of oat lipids. These
results are summarized in Table 1 (Hammond, 1983). As
shown 18:1 and 18:2 are the major fatty acids (FA) with a
large contribution from 16:0, whereas 18:0 and 18:3 are
minor components (0.5-4.0% and 0.5-5.0%) respectively.

Price and Parsons (1975) showed that oat lipids contained

from 70 to 76% nonpolar lipids (NL), from 3 to 10% phospho-
1ipids (PL) and from 7 to 17% glycolipids (GL). The major
component of the NL is triglyceride (TG). Free fatty acids
were reported to be between 2 to 12%, but this was strongly
affected by lipase activity as well as variety and location

where they were grown (Hammond, 1983).

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TBA Test for Evaluating Lipid Oxidation

The thiobarbituric acid (TBA) test is one of the most
widely used methods for the evaluation of lipid oxidation.
Sinnhuber et a1. (1958) attempted to clarify the nature of
the colorimetric reaction which occurs during the TBA test.
They proposed that the chromogen is formed through the
condensation of two molecules of TBA with one molecule of
malonaldehyde (Figure 1). Later they confirmed this
chromogen formation by analyzing the chromogen crystal by
mass spectrometry, nuclear magnetic resonance and infrared
spectrometry.

Dahle et a1. (1962) pr0posed a mechanism for the forma-
tion of malonaldehyde, a secondary product in the oxidation
of polyunsaturated fatty acids, based upon the autoxidizing
theory of Farmer and Sutton (1943). The investigators
showed that linoleate developed no TBA color even at
peroxide values of 2000 or greater, while fatty acids with
three or more double bonds yielded the color. These results
proved that only peroxide radicals which possessed B. Y
unsaturation to the peroxide group were capable of under-
going cyclization with the final formation of malonaldehyde.
Such peroxides could only be produced from fatty acids
containing three or more double bonds. Since oat lipids
contain few fatty acids containing three or more double

bonds (Hammond, 1983), it would seem appropriate that lipid

10

Figure 1. Formation of TBA pigment.

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oxidation be measured by other evaluation methods. However,
Caldwell and Grogg (1955) reported that the TBA test is well
suited to oat cereal. They used TBA to evaluate the storage
stability of two different oat cereals stored at 38°C and
confirmed a five to ten fold increase in Optical density

at 532 nm until rancidity was apparent.

There are several variations in methodology for the TBA
test. TBA can be directly reacted with a food product, or
a portion of a steam distillate of the food, or a separa-
tory acid portion of the extracted fat. Comparison between
the direct TBA method and the distillation method for
rancidity in fish (mackerel) was carried out by Vyncke
(1975). Excellent correlation between the two methods was
observed, although the TBA number, as determined by the
distillation method, was twice as large as that by the
direct extraction method.

Color deve10pment during the TBA test is usually
assessed by measuring the absorbance of the red pigment at
532 nm. However, other pigments have been observed notably
a yellow pigment with maximum absorbance at 450 nm. Marcuse
and Johansson (1973) studied the reaction of TBA with various
classes of aldehydes and found that alkanals, 2-alkenals,
and 2-4-alkadienals produce a yellow (450 nm) pigment with
TBA, while only 2-4 alkadienals and 2-alkenals produce the
red pigment at 532 nm. They proposed that absorbance at

450 nm could be used as an index of rancidity as well as the

13

value at 532 nm. However, Patton (1974) has questioned the
value of the absorbance at 450 nm, since these pigments can
be produced by the reaction of TBA with aldehydes which are
not oxidation products such as glyceraldehydes and aromatic
aldehydes. Caldwell and Grogg (1955) removed the yellow
pigment as an interfering color by selective absorption on
a cellulose column.

There is some evidence that TBA can react with compounds
other than those found in oxidizing systems to produce the
red pigment. Dugan (1955) reported that sucrose and some
compounds in wood smoke react with TBA to give a red color.
Baumgartner et a1. (1975) found that a mixture of acetalal-
dehyde and sucrose produced a 532 nm absorbing pigment
identical to that produced by malonaldehyde and TBA.

On the other hand, malonaldehyde can condense with some
amino acids. The condensation product is not hydrolyzed
under the conditions used in the TBA test (Buttkus and
Rose, 1972). Lower color yields might occur in an oxidizing

system in the presence of proteins.

METHODOLOGY

Sample Preparation

Fresh flaked oat cereal (without antioxidants) was
obtained from a local producer for use in this study. The
initial composition of the oat cereal was 64% carbohydrate,
14% protein, 7% fat and other materials (company's data).
Fifty grams of oat cerea1 were deposited into a plastic
pouch. An OA consisting of iron powder, water, and
catalysts, and weighing 4.8 gm was placed into certain
samples. Two different materials were used to make the
sample pouches. One pouch material was composed of Poly-
vinylidene chloride (PVDC) coated Polypropylene (PP)/
polyethylene (PE). The total thickness of this film was
86 um. The other pouch material was made from 84 um
polyethylene. The original pouch size was 20.5 cm x 18 cm
(length x width). After filling, every sample pouch was
vacuumed and heat sealed using the Super VacR Type GK 165R
vacuum machine (Smith Equipment). After sealing, 150 ml of
air was inserted using a 1000 ml volume airtight syringe.

A square shaped gum sheet (2.5 cm x 2.5 cm x 0.1 cm;
length x width x thickness), which had an adhesive surface

on one wide, was attached to the top portion of the pouch by

14

15

using the adhesive side. This gum sheet was utilized to
prevent gas leakage during sampling. The total inner

volume of the package was determined by submerging the
package into water in a 1000 m1 graduate cylinder. Volume
increase of the water indicated the total volume of the
package. Internal volume was calculated by subtracting the
volume of pouch material (corresponding to 10 ml) from the
total volume. The internal volume was adjusted to 255 m1
using a 5 m1 airtight syringe. The top of the pouch was
heat sealed, with a minimum amount of head space remaining
in the discarded part of the pouch. The final pouch
dimensions were 18 cm x 15 cm (length x width) and had been
four side sealed. The surface area of the pouch was 540 cm2.
Head space volume of these samples was measured by an Oxygen
Analyzer (Appendix 1 and 2) and found to be 185 m1.

Initial head space oxygen concentrations (1.0% and 5.0%)
were prepared by the same procedure with the exception of
nitrogen gas flush. After the cereal was put into the
pouch, nitrogen was introduced into the pouch by the
Super VacRType GK 165R. The desired oxygen concentration
was obtained by injecting air or extracting the head space
gas by the air tight syringe. The 02 concentration was
monitored using the O2 analyzer. The internal volume was
maintained at 255 m1. A sample package stored at high
relative humidity (RH), was modified to hold the saturated
salt solution (ammonium sulfate; (NH4)2504) inside the

16

pouch. One horizontal and one slanted heat seal were added
to the pouch in order to separate the saturated salt
solution ((NH4)2S04). In Figure 2 is shown the modifica-
tion. These samples could not be vacuumed, so the internal
volume was regulated using the 50 m1 airtight syringe.

After the oat cereal (with or without 0A) was deposited into
the plastic pouches (20.5 cm x 18 cm), horizontal and slanted
heat seals were added as mentioned previously. The top of
the pouch was also heat sealed. The internal volume was
regulated by the same manner except a 50 m1 airtight syringe
was used instead of a 5 ml airtight syringe. The final
internal volume and dimensions were maintained at 255 ml and

18 cm x 15 cm respectively.

Sample Storage

 

Samples were placed into one of five storage conditions.
The conditions were derived from combinations of three
factors - temperature, humidity and exposure to light.
Storage at 21°C and 45% RH was accomplished using a
controlled temperature and humidity room. Storage at 41°C
was accomplished using a temperature regulated chamber.
Relative humidity inside the chamber was held at 40% RH by
allowing water to evaporate from a bucket filled with water.
Humidity was monitored using a psychrometer. A PE bucket
(90 mil) containing a saturated salt solution ((NH4)SO4) was
used to maintain high RH (80% RH) at this temperature. A

17

Figure 2. Package modification for high RH (41°C, 80% RH).

 

 

18

saturated (NHAJZSOII held by cellulose paper

 

 

 

 

horizontal. seal I5 :1»

 

 

 

 

 

 

 

19

light exposure box made of corrugated board was maintained

in this chamber to create another condition. A 15 N fluores-
cent light was installed underneath the t0p flap of the
exposure box. The light intensity ranged from 40 to 90 foot
candles (Appendix 3).

Another temperature regulated chamber was utilized for
storage at 65°C. In order to maintain a moderate RH (45%
RH) packaged samples were stored in a PE bucket containing
saturated salt solution (Chromium trioxide; Cr03). Sample
conditions are shown in Table 2. Samples were withdrawn
periodically from each condition. Two pouched samples were
used for the modified TBA test, head space oxygen concen-
tration, and sensory evaluation. Temperature and RH

tolerances were 13°C and 15% RH respectively.
Index for Lipid Oxidation

Modified TBA Test

 

Caldwell and Grogg (1955) first applied the thiobarbi-

' turic acid test (TBA test) to cereal products including

oat cerea1. In this technique, extracted lipids were mixed
with water, TBA reagent and trichloroacetic acid. After
completion of the reaction, the aqueous layer was transferred
to a cellulose adsorption column in order to remove the
yellow pigments from the reacted solution. Optical density
(0.0.) of the (red) solution was measured at 532 nm.

Caldwell and Grogg (1955) reported that their method was

20

Table 2. Experimental conditions.

 

 

Tempera- RH Material Exposure 0A Initial 0
ture to light concentrat1on
21°C 45% onc coated No No 21%
PP/PE

21°C 45% PVDC coated No Yes 21%
PP/PE

41°C 40% onc coated No- No 21%
PP/PE

41°C 40% PVDC coated No No 5%
PP/PE

41°C 40% onc coated No No 1%
PP/PE

41°C 40% PVDC coated No Yes 21%
PP/PE -

41°C 40% PE No No 21%

41°C 40% PE No Yes 21%

41°C 40% onc coated Yes No 21%
PP/PE

41°C 40% PVDC coated Yes Yes 21%
PP/PE

41°C 80% onc coated No No 21%
PP/PE

41°C 80% PVDC coated No Yes 21%
PP/PE

65°C 45% onc coated No No 21%
PP/PE

65°C 45% PVDC coated No Yes 21%

PP/PE

 

21

applicable to oat cereal.

The modified method used in this study is basically a
combination of Caldwell's (1955) and Sidwell's (1954)
techniques. In Sidwell's methodology sample lipids were
melted with benzene. The reactive material in the benzene
layer was extracted with an acid solution (glacial acetic
acid) of TBA. The aqueous layer containing the reactive
material and TBA was transferred to a test tube using a
separatory funnel. The aqueous layer underwent reaction in
a boiling water bath with development of the red color.
Sidwell did not use an adsorption column. Separation
between benzene layer and aqueous layer was very difficult
when Sidwell's methodology was applied to the cat cerea1
used in this study. After vigorous mixing of the solution
containing the two layers in the separatory funnel, the
two layers formed an emulsion which caused an unproportional
separation of reactive material into the aqueous TBA reagent
layer. This separation ratio is critical for the TBA test

and was improved by centrifugation.

Modified TBA Test (M-TBA Test)

Twenty grams of oat cerea1 were utilized for each
measurement. Two M-TBA tests were executed for each
pouched sample. Therefore, a total of four M-TBA tests were
performed for a specific condition in each sampling time.

Twenty grams of the cereal were placed into a 200 ml beaker

22

and extracted with 100 m1 of hexane overnight at room
temperature. The hexane layer was filtered using a glass
suction funnel with an aspirator. Hexane (50 ml) was added
to the sample to complete the filtration. The filtered
hexane layer was transferred to a 250 ml flat bottom

boiling flask and vacuum distilled using a rotary evaporator
at 48°C. Drying of the lipid sample was completed by gently
nitrogen flushing the sample. The dried lipid extract was
weighed and then added to 10 m1 of benzene. After 10 m1 of
TBA reagent (0.67 gm of thiobarbituric acid diluted to

100 ml with distilled water, plus glacial acetic acid

100 ml) had been added to the flask, it was swirled and
shaken vigorously for four minutes. The samples were then
centrifuged in a 50 ml centrifuge tube for 15 minutes at
maximum speed (Model CL of International Chemical Centri-
fuge manufactured by International Equipment Co.) to
separate the benzene and aqueous layers. After the top
layer (benzene) had been removed by a disposable pipette,
the aqueous layer containing TBA and reactive material was
transferred to a screw capped glass test tube. The test
tube was placed in boiling water for exactly 30 minutes.
After reacting, the aqueous layer became orange colored.

A seven milliliter aliquot of the orange colored liquid

was transferred to the cellulose adsorption column (6 mm
inside diameter x 430 mm height) containing cellulose powder

(90 mm high; Whatman CC 31). Glass wool was used as the

23

stopper at the end of the column. This aliquot was forced
through with air pressure of 10.0 psi. Ten milliliters of
distilled water were then flowed through the cellulose
column, in order to elute the yellow colored pigment from
the column. A 10 m1 aliquot of aqueous pyridine (40 m1 of
pyridine diluted to 200 ml with distilled water) was then
forced through the column. Ten milliliters of this solution
was collected in a 10 m1 volumetric flask. The optical
density measurement of this solution (red colored) at 532 nm
was made against a blank solution which was obtained by the
same procedure except no lipid had been added. The optical
density was multiplied by a hundred and divided by the
weight of sample lipid (0.0. x 100/gm) which is referred to
as the modified TBA index (M-TBA Index).

Residual Oxygen Concentration of the Package

 

Residual oxygen concentration in the package was
measured using the Oxygen Analyzer LC-700 F (Toray Engineer-
ing Co., Ltd., Tokyo). This detects the amount of oxygen
in the sampled gas based on the electromotive force of the
Zirconium solid cell (see Appendix 2). A 5 ml sample of
gas was withdrawn from the package and injected into the
sample loop of the Oxygen Analyzer. The oxygen concentra-

tion was recorded from the digital readout.

Sensory Evaluation

 

The flavor of each sample was observed throughout
storage. A portion of each sample was stored at -20°C.
After 3 months of storage, each sample was numbered at random
.and evaluated for flavor and color change. There were 14
different storage conditions having 4 sampling times
including the initial sample, thus there were 57 different
sample conditions, each having 2 sample pouches. 2 pouched
samples were mixed and deposited into one numbered vial
(l to 57) with an airtight closure. Evaluation was
conducted once a day over 3 days. This evaluation was
performed by one researcher, so there was no statistical
significance to the results. However, the results were

used to show the general trends.

Oxygen Permeability of the Sample Films

 

The oxygen permeability of the sample films were //
measured using the Oxtran 100 Oxygen Permeability Tester
(Modern Controls Instrument, Rochester, Minnesota). This
instrument measures 02 transmission by an isostatic method.
The sensing device (coulometric) detects the amount of
oxygen passing from the oxygen chamber through the film and
into the nitrogen chamber. The 02 is swept via a carrier
gas to the detector. Gas flow rate (both N2 and 02) were
maintained at 15 ml/min. Permeability measurement were

performed at either 0% RH or 100% RH at 21°C. Relative

25

humidities at elevated temperatures (41°C, 65°C) were
calculated using a mathematical relationship (see Appendix

4).

Scavenging Ability of the Oxygen Absorber

 

The oxygen absorber used in this study was Type LH-lOOO
made by T6a Synthetic Chemical Industry Co., Ltd., Tokyo,
Japan and consisted of a 4.8 gm mixture of iron powder,
catalysts and water. To test its 02 scavenging ability,
0.5, 1.0, 1.5, 2.0, and 2.5 gm weight of the mixed powders
were put into the barrier package (PVDC coated PP/PE, 18 cm
x 18 cm; length x width). The surface area of the package

was 648 cm2

with headspace volume adjusted to 500 ml of air
by an airtight syringe. Water of which the weight was
equal to 10% of each sample powder, was also injected into
the package to create a condition of high relative humidity.
The oxygen concentration inside the package was measured by
the Oxygen Analyzer after 2 and 4 days at 21°C. The
scavenging ability of the oxygen absorber was calculated by
relating the amount of scavenged oxygen to the weight of
the mixed powder. The amount of permeated oxygen was

accounted for by this calculation, though it was almost

negligible.

RESULTS AND DISCUSSION

Storage Study

 

The M-TBA index varied depending upon the oxygen concen-
tration, which was affected by the initial oxygen concen-
tration, oxygen permeability of the package and presence of
oxygen absorber. M-TBA index of the original sample was
5.0 (0.0. x lOO/gm). After one month, PE pouched samples
with and without 0A had approximately a tenfold increase in
the M-TBA index as compared to the original sample, when
they were stored at 41°C, 40% RH (Figure 3). The M-TBA
index for either sample condition did not increase further,
however the TBA values were still high when compared to
other sample conditions. Distribution of M-TBA indexes
is shown in Table 3. The advantage of using 0A
was not significant, when analysis of variance
(ANOVA) for two factors (time and sample condition) were
applied to the result of M-TBA index (Table 7, 12).

Sensory evaluation of these samples after one month also
showed that they were extensively oxidized, resulting in
very strong odors (Table 5). The use of 0A did not prevent

oxidation from occurring for the cat cereal in the PE

26

27

Figure 3. M-TBA index as a function of time for oat cereal
packaged in PE, and stored at 41°C, 40% RH,
under 21% initial headspace 02.

28

333.5 5:.
5.8%... .85...

 

©

 

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q q d u

0.
ON

on

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0m

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40m

29

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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N8. N8. 8.... :.:N :.N_ :6 NN a. a: 3.88: m. 8 2
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a .N N .N. v .2 N. .2 I : .N .N 8N as 3.88: 8 = N.
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m. .: N .N. N .N. N .N. I : .: .N a. a: 3.88... 8 = =
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u .: a .N. N .2 N .N. I : .n .N 8N 8. 3.88: 3 = :_
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N .N. :.:N NJ: :.:N I :.o .N 3. 8N 3.88: 3 = a
98:... .8: 3. J. :8: :8 J. .8: N: J. 3: 8:... N: v N N o.
.3”. N.:: N.:: . :.3 I :.: .N a. s. 8 8 = :
8:: .J. .8: :.8 J. .8: 2:... A8: .3 J. 3: 8.: J. A: v N N o.
:.:N :.:N :.N... :.NN I :.: .N s. a. 8 :N = N
N... J. .8: :.m J. .8: :.N J. .8: N: J. S: 8.: J. A: v N 8?: N u.
N... :.N. N.:_ _.NN I :.m. .N 8N a: 388: 3 = N
:8 J. .8: :.N J. .8: :.8 J. .8: N: J. S: 8:... N: : N 2;. N u.
.8. n:— N.N_ :.:N I :.: N 3. as 3898: 9 = m
:8 J. .8: :.N_ J. .8: N: J. .8: J. S: 8:... A: : N 8;. N u.
:.:N vs. :6.— .. :.N. I :.o a a: a: 3.88: 3 = N
:.8 J. .82 :.N J. .8: :.:N J. .8: N... J. S: 8:... A: : N 8?: N :.
_._N N... :.:N :.3 I :.: .N a. s. 38.8: :. = N
N: J. .8: Y. J. :3 N: J. .8: 8.. J. :3 8.: J. A: N N 8:: N o.
: .N : .N. : .: : .3 I : .... .N a. s. 3.88: 9 .N N
8. J. .8: «N J. 2:: 2 J. N8: 3 J. :3 8.: J. N: : N . 8)... N u.
N... N... :.:_ :.Z I :.... _N a. a. 3.3.8... 8 .N.
.7. H53.: 3 3.: 3.33: .N... a... a.
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Table 7

3O

ANOVA table for a p x q factorial experiment with r replicates

 

 

 

 

 

 

 

 

 

uean
source sum of squares d.f. square F ratio
9 H5.
Factor A 85. = qr23( y; - y )2 p - 1 HS.
1'] "SE
HS;
FactorB SSB=Pr2(YJ - y )2 q-l HS.
"' HSE
9 C "8‘
Inter- SSA3=rE£(Yu 'Yi ’YJ+Y)2(P'1)(Q‘1) HS"
action """ "SE
A x B
P Q 1‘
Residual SSE =1 Eggs Yuk - Y“): pq(r - 1) "SE
P Q I“
Total 222(3’1411'? )2 qu'l
I'IJ'IIII
Here SS.
HS. =
p -1
55 I
"S; = '
q -1
35 an
"5.3 =
(p - l)(q - l)
SSE
"SE =

PQ(r - 1)

31

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m.o n.m~ m o.pp :6.Noa
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as .ONoam.
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a. o.am~

32

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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.m 2...;

33

package. Oxygen concentration in the PE packages were

nearly zero (less than 0.0l%) within one day (Table 4),

however, after 3 days, 02 concentration was the same

as in the atmosphere (Figure l2). The DA used in this
experiment has a capacity of 160 ml oxygen in ambient

condition (see Figure 28,‘Table T7). The permeability of the

PE film was 4100 ml/m2/day at 41°C, 0% RH (Figure 26, Table 16)
which corresponds to 220 ml/pouch/day. The head space of

the sample pouch was 185 ml (Appendix 1), so 38.7 ml of

oxygen (185 x 0.209) was the initial quantity of 02 in the
pouch. Therefore, the 0A should lose its absorbing ability

by 3 days, assuming the driving force was maintained at

0.209 atm.

1) (160 — 38.7) mlépouch

220ml/pouch.day.atm x 0.209 atm = 2'6 day

-38.7 :initial amount of 02 in the pouch (ml)

~160: absorbing ability of 0A (ml)

.220; permeability of the PE film (ml/pouch.day)

-0.209: pressure difference between outside and inside.

Assumptions

~0A initially absorbed the headspace 02 completely within
a few hours.

~0A absorbed all permeating 02 immediately as it came through

the package.

134

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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35

Figure 12. Headspace 02 concentration as a function of time
for oat cerea1 packaged in PE under 21% initia1
headspace 02 and stored at 41°C, 40% RH.

36

m><o
co. om on Oh om On 0.. on ON 0. o

d d d

 

d

.833... 5:. 3:6 ..... a .i-
.333... 2.2:: Ilo lllO.l..

 

 

 

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zo_._.<mhzmozoo .o

37

Figure 28. Absorbing abi1ity of the 02 absorber as a
function of weight at 210C.

 

38

0— High hmidity condition

 

—X x— Hedit- huidity condition

 

VOLUME ABSORBED 02
(m l)

200 '-
lSO '-
IOO

50

 

 

 

o 0.15 KO 115 7.30 2.5 3T0
WEIGHT OF nasoasmo MATERIALS
gm

39

 

 

 

 

 

 

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5.3..\A. o... u >

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.oAA Ao.ov Ao.ov m~.A
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40

Figure 26. 02 permeability of PE and PVDC coated PP/PE as
a function of temperature.

41

—0—————@— PE
( W at 21°C )
-- X--------x-- W112 003% PP/PE
( 100m at 21°C )
0 (025m at. 21‘C)
I0,000 :- \
TS E 5“\

(ET%T @\

IOOO

IOO

IO

 

 

'._$$_l 1 4..

2.90 3.00 3.10 3.20 3.30 3.40 3.50
TEMPERATURE (-T—1K—xlo’)

42

 

 

 

.m. A. v . .... ..
.. A. . . ._.. ..
A.. A. . . .m.. .N
.F. A.._. .A ...N ..
F. A.... N. .A.. ..
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..EA.. .F.... .5. .. .H.A....s... N. ..A .....

43

After 0A was no longer able to absorb 02, accumulation
occurred due to permeation from the outside. 02 concen-
tration in the pouch increased depending upon the permea-
bility of the pouch material. The driving force would
decrease, with increased 02 concentration in the pouch.
The amount of 02 permeating through the package changed,
according to the following relationship:

2) An = (0.209 - A0 + Al + A2 + "° + AWU x 9.17
185
An; Amount of 02 permeated from outside from n-l to n
hours after 0A lost its ability to absorb 02 (ml)
9.l7; Permeability constant of the PE film (ml/pouch.
hour.atm)
l85; Headspace volume of the pouch (ml)
A0 = O

(0.209 _ A0 + A1+ ooo + An-]
185

n hours. (atm-ml/ml)

); Pressure difference after

 

The amount of 02 = Ao+ A] + A2 ... + An

Calculated results are shown in Appendix 6. These

results show that, after 28 hours (which corresponds to
4.2 days from the time, 0A was put into the pouch) that
the headspace 02 concentration was l7.8%.

The headspace 02 concentration in PVDC coated PP/PE,
stored at 4l°C. 40% RH changed dependent on the initial

02 concentration and capacity of 02 absorber (Figure 13).

44

Figure 13. Headspace 02 concentration as a function of time
for oat cereal packaged in PVDC coated PP/PE and
stored at 41°C, and 40% RH.

45

.33....6 5.: ..A. 008%....— _2:£ «E
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zo_._.<m._.zmozoo .0

46

Samples containing 2l% initial headspace 02 absorbed all 02 in
the package by 35 days. Least square regression analysis was
used to treat the sample data. Packages (no DA) with initial
headspace 02 concentrations of 5% and 1% were reduced to

zero by 60 days. Packages, packed with 02 absorbers and

an initial 02 concentration of 2l%, were reduced to zero
within a few hours and maintained this condition until 60
days. A gradual increase was noted until at 90 days it was
1.7% (Figure l3). The headspace 02 concentration of PE
pouches changed much more rapidly compared to that of PVDC
coated PP/PE pouches (41°C, 40% RH). As mentioned pre-
viously, the headspace 02 concentration for both packages
dropped to nearly zero within a few hours, headspace 02
concentration in PE pouches then increased to 20% by 6 days.
02 concentration in PVDC coated PP/PE pouches was maintained
at less than 0.01% until 60 days (Figure l4). High barrier
package materials are important in order to prevent the 02
absorber from being overwhelmed. From the headspace 02
content, the amount of 02 consumed an average 02 consumption
rate (AOR) were calculated. These directly relate to the
oxidation of the oat cereal, and changed depending upon
oxygen pressure, temperature, surface-to-volume ratio and
extent of reaction. AOR is an index of 02 consumed during

a specific time interval. The time intervals were divided
into 0 to 20 days, 20 to 50 days, and 50 to 90 days. In

the fastest 02 consumption condition (exposure to light,

47

Figure l4. Headspace 02 concentration as a function of time

for oat cereal packaged with 02 absorber and

stored at 4l0C, 40% RH, 21% initial headspace
02.

48

. m»<o
co. 0m om on 0m 0m 0? on ON 0. o

I .III 3
d d 1 1‘“\.‘li a I 1‘
\
\\ .
\

 

\

‘Q‘

.2

95... 3.898: -..-oulann-o-u..
... 9 out . m.

.o\...
20....<~..szozo u no

 

 

ON

4

 

 

49

41°C, 40% RH, PVDC coated PP/PE), the initial headspace

02 (20.9%) was fully consumed within 23 days (Figure 15).
Once the headspace 02 was consumed, the consumption rate

was limited by the permeability of the package material.

The change in headspace 02 concentration was a result of 02
consumption by the cereal and permeated 02 from the outside.
The actual results were agreeable. The oxygen concentration
of PE pouched sample with GA was 17.8% (Table 4) after 3
days. This indicates that the influence of 0A in this
package on lipid oxidation was very little. As shown, PE
pouched product with and without 0A had very similar M-TBA
indexes and sensory scores. The TBA index for the oat
cereal without 0A was dependent on the initial head space

02 concentration, permeability of the film, and storage
conditions. After 1 month, the PE pouched sample, which

had an initial head space 02 concentration of 20.9%, had

the largest increase in M-TBA index, followed by the PVDC
coated PP/PE package (20.9% 02 No - 0A), the third was the
5% initial headspace 02 PVDC coated PP/PE pouch. The

sample with the smallest M-TBA index was the 1% initial
headspace 02. The M-TBA index of the PVDC coated PP/PE
package packed with GA, an initial 02 concentration of 20.9%,
was lower than that of the same package having an initial 02
concentration of 1% with no 0A. This was significant at the

99% level (Table 8). After 2 months, the M-TBA index for

50

Figure 15. Headspace 02 concentration as a function of time
for oat cerea1 packaged in PVDC coated PP/PE
and stored at 41°C.

51

5.33.... ......
...»: 3 8:898 ...58

Essa... ...... .58
.353»... .. ... .5...

.332»... 2
.2... s 2:8...» .58

5.83:... 9. £58 .

£53.... 2 .55.

algllllnm— la
Il..llll.ll

iii..-

m><o

oo— om om on cm 0... o¢ on ON 0. o

 

 

i.

o.

-
_——--—--J— mu-j-j ---- ----------.

-m.

 

ON

.o\o.
zo...<m.~zmozou no

Table 8

52

ANOVA for the Date of sampling x Packaged condition ( 41°C. 40%RH
PVDC coated PP / PE. 21% initial 02 concentration. with 0; absorber
v: 41°C. 40%RH. PVDC coated PP / PE.1% initial 02 concentration
no 02 absorber )

ANOVA table for a 4 x 2 factorial experiment with 4 replicates

 

 

wean testing
source sum of squares d.f. square F ratio hypotheses
date
(Factor A) 110.7 3 36.9 3.6 significant
( 95% )
packaged
condition 154.4 1 154.4 15.0 significant
(Factor B) ( 99% )
Inter-
action 63.3 3 21.1 2.1
A x B
Residual 246.9 24 10.3
Total 575.4 31

 

 

Data of H-TBA index used for the ANOVA ( 41°C. 402RH PVDC
coated PP / PE. 21% initial 0: concentration . with 02 absorber
v: 41°C. 40%RH. PVDC coated PP / PE.12 initial 02 concentration
no 02 absorber )

 

 

 

Factor A storage tern ( day )

Factor B 15 28 59 90

1 14.1 12.1 13.7 14.6

21% initial 2 14.1 10.7 12.3 12.3
02 conc.

with absorber 3 10.6 9.6 15.1 10.5

4 9.8 8.3 9.4 8.3

1 14.6 14.9 13.6 17.8

1% initial 2 11.2 11.1 18.1 20.0
02 conc.

no absorber 3 15.8 11.9 27.5 14.2

4 10.4 12.7 17.8 24.2

 

 

53

high barrier packaged oat cereal (20.9%, 5% and 1% initial
oxygen head space) was almost the same (20 0.0. x lOO/gm)
irrespective of initial 02 concentration. This M-TBA
index is twice as large as that of sample containing 0A
(10 0.0. x 100/gm) and four times as large as the original
sample (5.0 0.0. x lOO/gm) (Figure 4). The difference in
Um M-TBA index between 5% and 1% initial 02 concentration
was not significant (Table 9). The difference between 21%
and 5% initial 02 concentration was significant at the 95%
level (Table 10) while the difference between 21% initial
02 concentration with and without 0A was significant at

the 99% level (Table 12).

Change of headspace 02 02 permeated — 02 consumed

Total headspace (185 m1) * (final
02 concentration - initial 02

concentration) (1)
t
o

02 permeated = Ppouch*[ P (t) * dt (2)

Amount of 02 consumed and AOR (t — t days) are shown by

x y
the formula (3) and (4).

t
02 consumed = Ppouch*J P (t) * dt - 185 * (02 conc. (t) -
o

02 conc. (0)) (3)

 

AOR (tx _ t days) = (02 consumed) ty
y

t
(ty'tx) x

54

 

 

 

 

a w 3.. .32.
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A uwauomam no o:

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.... \ .... 8:8 8....
«axon. x we..a;am .0 o.a= o.. co. .>oz.

m m..a.

55

 

 

 

 

.m o.mm~. .a.oe
m.m. e. ....m .aee.»m.
..8. ...
.cau...=».m ... ...N. m m.moa =o..ua
-uouc.
. "mm c .. case...
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vommxoac
A «mm V
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can:
monocuoaag o..au m ouaaaw ...c awkwaan we saw mouse»
mamumo. cam:

A uoauOmna No on
.co..mu.=mu=oo no .a...=. um.mm \ a; cwuaoo o=>m .=mnov .o..v a»
coacomna «o o: .co..au.cmo=oo ac .a...=. NHN .mm \ mm voaaoo 92>;
amuov .oo.v V so...v=ou umumxoam x u:..a1am .0 can: as. no. c>ozc

ofi m.aae

56

Figure 4. M-TBA index as a function of time for oat cerea1
packaged in PVDC coated PP/PE and stored at 41°C,
40% RH.

57

£383..
5 ...... .c 8338.. .a...... fin

coffin
.o .85... ... 88min. ......c. u.

1 £8.03:
~.. .35... ... 09838.. ......e. um.

3.3.8.... _

... .35.... no 883 3...... a."

m»<o
8. om om 2. ow on 0.. on 8 o. o

q u d u q -

 

 

 

 

 

.fi
- o.
- om.
. on
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4 4|. .2.
1.41.1.5]-.. . ....
. 8.25.
I . X
x - 8
x82.
<3-..
4 om

58

Fpouch: permeabiiity constant of the pouch (m1/pouch*day*
atm)

P(t): Pressure difference between outisde and inside the
package at 5 days (atm * mi/mi)

02 conc. (t): headspace 02 concentration as a function of

time (mi/m1) (final 02 concentration)
02 conc. (0): initial headspace 02 concentration (mi/m1)
(02 consumed) ty : amount 02 consumed during certain time

tx

(from tx to t days)

y
Here

P (t) = 0.209 - 02 conc. (t) (5)
0.209: Outside concentration of 02 * 1 atm (atm * mi/mi)

02 conc. (t) can be assumed to be a combination of the

serial straight iines. These 1ines are obtained as ieast
square regression 1ines.

When
Oétgt]

02 conc. (t) = a1 t +

02 COHC. (0)

(6)
S S
t1-t-t2
02 conc. (t) = a2 (t - t1) + 02
conc. (t1) (7)
< <
t =t=t

59

02 conc. (t) = an (t - tn-l) + 02 conc. (tn-l) (8)
Here t] is a day when first straight line connects to
second line. As the same way tn is a day when n - lth

line connects to n th line.

While
02 consumed = Ppouch *[Z P (t) * dt - 185 * (02 conc.
(t) - 02 conc. (0))
P (t) = 0.209 - 02 conc. (t) see (3)

Calculate the amount of 02 consumed in serial orders.

When
5 _
O-tft]
_ t _ t
Ppouch *J P (t) * dt = Ppouch *J (0.209 - 02 conc.
0 0
(t)) * dt
_ t
= Ppouch *J (0.209 - a1t - 02 conc. (0)) * dt
0
__ 612 *
= Ppouch * ( - l? t + (0.209 - 02 conc. (0)) t ) (9)
185 * (02 conc. (t) - O2 conc. (0)) = 185 *
(alt + 02 conc.(0)) - 02 conc. (0)) = 185 * (aTt) (l0)
So

a
02 consumed = Ppouch * (-—% t2 + (0.209 - 02 conc.

(0)) * t) -185 * (at) (11)

60

When
t'l-t=t2
O consumed = (0 c0nsumed) t] + (O consumed) t (l2)
t = ’ *St * _ *
(02 consumed) t1 Ppouch t] P (t) dt l85 (02
conc. (t) - O2 conc. (t])) (13)

t
Ppouch *Jt P (t) * dt
l

— t
Ppouch* It (0.209 - azt + azt1 - 02 conc. (t]))

1

* dt
= P OUCh * (.a2 t2 + (O 209 + a t - 0 conc (t ))
p —7 - 2 1 2 ' l
* t)t (l4)
‘1

l85* (02 conc. (t) - 02 conc. (t]))

185 * (a2 (t-t1) + 02 conc. (t1) - O2 conc. (t]))

185 * (a2 (t-t1)) (15)

(02 consumed) t] is calculated from the formula (ll).
0

61

From (13), (14) and (15)

(02 consumed) : = Ppouch * (-:E t2 + (0.209 +
l

2
t
azt1 - 02 conc. (t])) * t)t1 - 185 * (a2(t-t])) (16)
(.a2 t2 + (o 209 + a t - 0 con (t )) * t)t
‘2 - 2 1 2 C- 1 t1

= _32 * (t2 - t1) + (0.209 + a t - 0 conc. (t1)) *

“2 2 1 2
(t - t1)
_ :2 * (t2 t ) + t * (t t ) + (O 209 0
- ' 2 ' 1 a2 1 ' 1 ' ' 2

conc. (t])) * (t-t1)

2

= ..i% * (t-t1) + (0.209 - o conc. (t1)) * (t-t1) (l7)

2

So 02 consumed

2

= Ppouch * (-ig * (t-t1) + (0.209 - 02 conc. (t1))

t1

* (t-t1)) - 185 * (a2 (t-t]))+ (O2 consumed)0

See (12), (16), and (17)

By the same way

- § §
tn 1 t tn

62

02 consumed

_ a 2
= Ppouch * (-—% * (t - tn-l) + (0.209 - 02 conc.

(tn-1)) * (t-tn_1)) - 185 * (an(t'tn-1)>+ (o2

consumed) t3'1 (18)

The calculated results for 02 consumed and AOR are shown in
Figure 19-25, and Table 6. In Figure 19, the relation
between the amount of 02 consumed and M-TBA index as a
function of time for oat cerea1 packed in PE and stored at
41°C, 40% RH, 21% initial headspace 02 is shown. Head-

space 02 was consumed rapidly from 20 to 45 days. 02 was
still absorbed after 45 days, though the amount was rela-
tively small. The M-TBA index generally behaved in the same
manner. It increased for the first 30 days, and then leveled
off, probably because malonaldehydes were being consumed by

proteins.

The relation between the amount of 02 consumed and the
M-TBA index of pouched samples in PVDC coated PP/PE with
different initial headspace 02 levels and stored at 41°C,
40% RH are shown in Figures 20 and 21. Oat cerea1 packed
in 21% initial headspace 02 consumed more 02 than samples
containing 1% and 5% initial headspace 02. The 1% and

5% samples consumed 02 in a similar way. The sample packed

in 1% initial headspace 02 consumed 22 ml 02 while the

63

Figure 19. 02 consumed and M-TBA index as a function of
time for oat cereal packaged in PE and stored
at 41°C, 40% RH, 21% initial headspace 02.

64

.

  

 

o.
m.
ow
mm
on
84.x”. ...v on
oe
xwoz_
<m.-2 me
cm
on

T

T

r

 

m»<o
8 on ow on cm 2.. om cm 8.1
Too om cm on 8 on 9. on 8 o.

. q .

 
 

ezszeeszxusasa.o u ........

 
 

5.33%.. .85.: .5388 ...

 

eaasaogzzzigce;. :0:-AY:
hasseo=§==.§zt§v=

  

   
    

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.ou
.on
-ow
son
.om
1o.
.om

;.um
..E.

vussmgou «o

0..

1*

1

.ON.

 

ion.

65

Figure 20. 02 consumed and M-TBA index as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 41°C, 40% RH, 21% initial
headspace 02.

66

m><o

O 0. ON on O... on ow Crow cm 00.11

o.
m.
8
mu
on
Aoo........m..ov mm

Ce

 

xuoz_
<m»-2 mv

cm
3.

 

    

‘1."

q d c - - “III-lulllllld II IJ 1 [q 11

'
any """"

  

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““‘ "
o.--

 

5.33.... ...... as... 3.-.. 1911.6. I 5.33.... ...... 3593 a uuuuuuuu
03.8%... .85... .8... a... 19.1191. 38...... .85... 8.523 ...

.

I

 

 

loo. om om 2. o... o... 3 on cm 2 .o

0.
ON
on

0v

.8

ow
05
cm

......

 

35350 no

67

Figure 21. 02 consumed and M-TBA index as a function of
time for oat cereal packaged in PVDC coated
PP/PE and stored at 41°C, 40% RH.

68

o

m*<o

o. om on 3 on o... 2.8 om 8.1. .
loo. om om 2. 8.8 ow on 8 o. o

 

 

T

 

. . u u q . .

 

1 ow
- on
.. om
. ... 88.32. 3:... a. . . . ... 8388.. 3:... a. .
x8... 5...-.. ...Q lllll @11. 3.83%.. ...... 3333 .o IIIIIII
. ... 8238.. 3:... E v . .... 83.3... 3:... 6 .
.8... 5.-.. lellel .328 ...

......

32350 «0

69

Figure 22. 02 consumed and M-TBA index as a function of

time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 410C, 80% RH, 21% initia1
headspace 02.

7O

m><o

o 0. ON on 0v 0m 0m ON on om 00.1
too. cm 00 Oh om on 0* on ON 0. o

 

 

 

 

 

. . q 1 1. lllqll I. 1|qu |.| Jllll. l
1 o_
1 ON
5 ............. \\
. on
1 o¢
mm : L on
on 1 L om
IBM! -
€2.86. an , 2.
O¢ I . om
xuaz_
(mkuz me 1 3::
.3832. ...... .8... 5:-.. ......201. .8825. ...... 8888 ... ........ .
Om 1 10.58.30 .5
, .3828... .85... .8... E-.. lollelz .8832: .85... .388 ...
mm fl

71

Figure 23. 02 consumed and M-TBA index as a function of

time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 21°C, 45% RH, 21% initia1
headspace 02.

72

€0.41...“ ...v on

.802.

ON

mN

on

0..

<m.-: me

Om

mm

m><o

0. ON on ov on 00 Oh om om 02....

too. 0m 00 Ch 00 on ov on ON 0.

 

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3.82.... ...... .8... ...... {mi-in.--

£8.88... .85... .8... ...... loll-0.!

.383... ...... 85.8.. ...
.383... .85... 889.8 ...

 

L

0?

On
00
ON.

0w

3....

 

35.8.30 .0

73

Figure 24. 02 consumed and M-TBA index as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored at 65°C, 45% RH, 21% initia1
headspace 02.

74

 

mm-
on.
Auuwmll on-
00. x00
05.
xmaz_
<m.-: m.-
Om 1
mm-

 

m><0

o. 8.0.. o.. o... 8 o..- om cm 8.1
18.0.. om o 3.....- oc on cm 2

4 - u - Jill ldl 14 lllldl '4 ill-«1 «I I I4 ll

 

.2833. ...... 53.9.8 ... .-ui:i--... -...

 

382.... .85... 8828 ...
.882... 5... .8... ...... --o ...... Q-..
858...... .8... .. .8... 5:-.. .Iolllol

 

0

 

0.
ON
on

0?

.om

00
0s.
00

00
3....
10:30:00 «0

0:

 

75

Figure 25. 02 consumed and M-TBA index as a function of
time for oat cerea1 packaged in PVDC coated
PP/PE and stored under light at 41°C, 40% RH,
21% initia1 headspace 02.

76

0

m><o

0. ON on 0... 0.0 00 ON ON om 00.1
T00. om 00 0... 00 00 0V 0n 0N 0. 0

 

<m.-: m.-

 

 

.B.............. .8... .. ...... ...... ITEI .382... .85... 8528 ..

d d 1 qllll flllll Idll

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3....
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77

 

 

 

 

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om.o mo.o o._ zzz ooz uozoo oooooo oozo zoo oozo
om.o m.m mm.o zzm oz mo zoo oozo
mm.o om.o oN.o zz oz mozoo oozooo oozo zoo oozo
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om.o zm.o ~._ zzz oz mozoo oooooo oozo zoo oozo
mm.o Pm.o om.o zzN oz mozoo oooooo oozo zoo oozm

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.ucou No
zoozzs .Aozoo No-zov zoo zozozoz ozozz zozzoooz zz oooooooosoo
.wumg coouqssmcou No mmmgm>< .o mpnmw

78

sample packed in 5% absorbed 28 ml 02 up to 60 days, when all headspace

02 was consumed. After 60 days, both samples absorbed all 02 permeating
through the pouch. The difference of 6 ml did not cause any effect on the
M-TBA index. The M—TBA index of both samples was very similar.

The OAR (0-20 days) for these samples (2l% initial 02 concentration
packaged in PE with and without 02 absorber, 21%, 5% and l% initial 02
concentration without 02 absorber packaged in PVDC coated PP/PE) were
respectively 0.82 ml/day, l.2 ml/day, 0.43 ml/day and 0.30 ml/day. The
PE pouched samples had a smaller AOR (0-20 days) than the PVDC coated
PP/PE pouched samples (both 21% initial headspace 02 concentration),
however during the next period (20-50 days) PE samples had an AOR of
3.6 ml/day and PVDC coated PP/PE samples had an AOR of 0.87 ml/day.

The comparison ofrFTBA indexes for PE and PVDC coated PP/PE products
containing absorbers is shown in Fig. 5. The statistical significance
of these comparisons is shown in Table ll. The level of headspace 02
was a very significant factor in lipid oxidation. The concentration of
headspace 02 in PE pouches was almost the same as the external environment,
while PVDC coated PP/PE controlled the amount of 02 in the headspace
because of its barrier properties. With this package, zero 02 concen-
tration should continue for up to 358 days by calculation; however

the actual 02 concentration was 1.5% at 90 days. The oxygen absorber
consisted of iron (Fe) and several catalysts, and was precisely
prepared in order to absorb 02 under a broad range of circumstances.

The fundamental reaction involves the oxidation of iron. The

79

Figure 5. M-TBA index as a function of time for oat cereal
packaged under 2l% initial headspace 02 with
02 absorber and stored at 41°C, 40% RH.

80

m><o
8. mm mm oo oo 8 oo on on o. o

u
q d u u

-on.

.0?

 

O
235 3.88 SE 8:8 8: lolllfill A so
29.: .288 E II©|IIII©II 00.... .o v
. Om
o xmoz_
, 42...:

40m

 

81

 

 

 

 

fin v.vvo~ ~auoa
~.v~ vu v.ovm _a=ewnom
38mg no;
“caumuucamm m.> v.-~ m ~.vmm comaoa
-uma:_
A umm V Ac acauamv
accumumcumw m.mm H.vmp fl c.vmh comamvcou
uouaxuaa
Aummv
accomumcmmm v.v m.~o m m.mm~ Ac acauamv
mama
monogzonzg Oman» a oumaam .u.u magmas» we saw ouuaom
ucmumma cams

A ponuomna No
ozonum: ccm zz_3 .comuauacoocoo «c _mmam=m N~N .mm \ mm wouaoo 09>;
zanov .uofiv V comemccou cmnmxoam x u=m_numm we was: o:a no“ epozc

H~ o_nmp

82

absorbing ability will decrease in low temperature, because
the activation energy is not sufficient. The absorbing
capacity will increase in high temperature, until the
temperature reaches a point where the reaction will be
suppressed. Because this is a reversible exothermic
reaction, it will move in the reductive direction in
extreme high temperature. This suppression did not occur
at 41°C, as this temperature difference (2l°, 4l°C) is not
sufficient to affect the chemical equilibrium.

Low levels of H20 in the product package system may
possibly explain the low absorbing ability. H20 should
permeate from the outside into the pouch at 4lOC, 40% RH.

Probably this RH was not high enough to allow the absorber
to fully absorb 02 at this temperature.

Sensory evaluation suggested that when the M-TBA index
reached 20 (0.0. x lOO/gm) oxidative change had taken place.
Some oxidative aromas were noticed for samples after 3
months, with an M-TBA index of 10 (0.0. x TOO/gm).

Storage in high relative humidity (41°C, 80% RH)
resulted in different M-TBA index and oxygen uptake as
compared to storage at medium RH (4l°C, 00% RH in PVDC
coated PP/PE). Headspace 02 decreased more slowly at high
humidity than at medium humidity (Figure l5). It did not
reach zero even at 90 days storage. Samples with 02
absorber maintained zero headspace 02. At 90 days, one of

the pouches had a headspace 02 level of 20.9%, probably due

83

to a seal failure. At high humidity samples packaged in
the PVDC coated PP/PE pouch with and without 0A showed
slight increase in the M-TBA index during the storage period
(Figure 6). The M-TBA index was almost the same as the

0A contained sample at the same temperature (41°C) and
medium RH (40% RH). There was no statistical difference
between the results for these two samples (Table 14).
Samples surrounded by high RH absorbed more 02 than samples
surrounded by medium humidity (40%) (1% and 5% initial
headspace 02, PVDC coated PP/PE) (see Figure 21, 22),
however M-TBA levels were not higher. AOR (0-20) for

this sample condition (21% initial headspace 02, PVDC
coated PP/PE, 80% RH, 41°C) was 0.66 ml/pouch.day. Water
is known to retard lipid oxidation in many dehydrated and
low-moisture food products. Hydrogen bonding of hydro-
peroxides with water could occur (Aw) in a methyl linoleate
model system (Aw 0.5) (Maloney et al., 1966). Quast and
Karel (1972) showed that the oxidation rate of potato

chips was lowest in 40% RH. At high RH (75% RH at 37°C),
the rate increased considerably, possibly due to increased
mobility of the reactants. Product kept at 75% RH also
showed strong nonenzymatic browning. At high humidity
(41°C, 80% RH) the MeTBA index and the AOR (0-20 days) were
less than at lower RH. Oxidation was observed after 2
months by sensory evaluation for samples packed without 0A.

The oxygen consumption rate might be higher than the

84

Figure 6. M-TBA index as a function of time for oat cerea1
packaged in PVDC coated PP/PE under 21% initial
headspace 02 and stored at 41°C.

85

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oo. oo oo oz. 8 oo oo on oz 9 o

 

 

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.zzzoz .o.zo v oozozoeoo oooozooo z oez_oeoo .o oooo oz. ooo ozozo

v~ ozone

87

calculated value (0.66 ml/pouch°day, 0-20 days) because
the permeability of PVDC coated PP/PE film at high humidity
could be larger than at medium humidity.

Exposure to light did not cause further increase in
the M-TBA index compared to no light exposure (Figure 11),
however it did affect the amount of 02 consumed and the AOR
when all headspace 02 had been consumed by the cereal.

The AOR (0-20 days) under light exposure was 1.9 ml/day-pouch,
while the AOR (0-20 days) was 1.2 ml/day-pouch in the dark
(Table 6). Figure 15 shows the influence of RH and light
exposure on headspace 02 content. Sensory evaluation of

the samples indicated oxidized product even after 0.5

month. '

Singh et a1. (1974) showed that an increase in light
exposure caused an increase in the rate of riboflavin
degradation in whole milk and that oxygen uptake can be
expressed as a function of light intensity. In this study,
light intensity ranged from 40 to 90 foot candles (430 lux
to 970 lux, Appendix 3). These intensities are approximately
the same as display case lighting (500-1000 lux, Uematsu
and Someya, 1978). Light exposure accelerated product
deterioration even when packed with GA. This change was
not detected by the M-TBA index, but by sensory evaluation
after 2 months storage. Possibly competitive consumption of
permeated 02 by the 0A or by the lipid in the oat cereal

may have caused the difference. Under light exposure the

88

Figure 11. M-TBA index as a function of time for oat cerea1
packaged in PVDC coated PP/PE and stored at 41°C,
40% RH, 21% initial headspace 02.

89

ozoo .
oo. oo oo oo 8 oo oo on o... o.

o
w

 

 

 

.2333 ...... 2.... o. 2:83. 1.3 all . ov
.359... ...... ...... 3 82.85 oz I... 0.1
booze... oo ....o: 3 page... limiting .i ABxIlQI.O v
5333...: 8 ...—u: 3 8:898 oz IIX IIIIIXI... . Om
xmoz_
<mhuz

 

90

difference between the M-TBA index with and without 02
absorber was significant at 99% level (Table 13).

A temperature effect was also observed. At 21°C
(21% initial 02 concentration, 45% RH, PVDC coated PP/PE,
no absorber) headspace 02 decreased linearly throughout
100 days of storage. Headspace 02 remained at zero with 02
absorber (Figure 16). The amount of 02 consumed (Figure 23)
was relatively small compared to the sample stored at 41°C
and 65°C (Figure 20-24). M-TBA index of the sample with
and without 02 absorber and stored at 21°C increased
slightly. Headspace 02 (21% initial 02 concentration, 45%
RH, PVDC coated PP/PE, no 02 absorber storage 65°C) decreased
quickly and thereafter remained about the same (2-6% 02 )
followed by an increase to 12%. The 02 concentration with
absorber was maintained at zero for 90 days (Figure 17).
The change in headspace 02 for all 3 temperatures is shown in
Figure 18. According to the permeability of PVDC coated
PP/PE at 65°C (Table 6, Figure 26), the time span in which 02
absorber could maintain zero 02 concentration in this condition

was:
160: Absorbing ability of

02 absorber at 21°C (ml)
38.7: Amount of headspace 02

 

160 - 38.7 _ (mi)
10.8 x 0.209 ' 54 (dayS)
10.8: Permeability constant of
‘onc coated PP/PE at 65°C
0.209: Pressure difference

(atm ml/ml)

91

 

 

 

 

S :68 .58
m.~ oz ..mm .ooozooz
m a z
N.. o.» m ~.cz oo..oa
-uoaa—
A flaw v A: nauuamv
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genomes;
A «8 V .
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38
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”guano“ cam: .

A uoauowaa no “accum: can gum:
.muamoaxo .gmw_ .comuauucoocoo ac _m_um=_ RAN .mm \ mm cognac 95>;
.==Nov .ooAv V comamucoo cmumxoam x mam—asam no man: as“ ace <>ozc

mA m_nme

92

Figure 16. Headspace 02 concentration as a function of time
for oat cerea1 packaged in PVDC coated PP/PE
and stored at 21°C, 45% RH.

93

m><o

8. oo o oz 8
1 1m.) 9mm: 4 10.. on 8.. o. 0

Lo.

   

_
_
_
_
_
+ m _
_
_
c3332.. ...... (in... 1110;... _
6.332.. .8... ... a o l..

 

 

Ao\e.
zo_._.<¢._.zuozoo no

94

Figure 17. Headspace 02 concentration as a function of time
for oat cereal packaged in PVDC coated PP/PE
and stored at 65°C, 45% RH.

95

m»<o

oo— om cm on om om ow on ON 0. o
Illdl a. 4f l. 141 q.

  

 

 

 

 

 

m
0

._ o.

_

JV
4 m.

.388... ...... 1.9.111931

.B.o£o.o.§...z IO 0 ow

AX.
zo_._.<mhzmozoo «o

96

Figure 18. Headspace 02 concentration as a function of time
for oat cerea1 packaged in PVDC coated PP/PE
and stored either at 40 or 45% RH, 21% initial
headspace 02.

97

.3332. ... ...
8.8%... ... ...
.3332. ... ...
..3332c 8
258389 8
5333.3. 9.

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x x11 /. .
-ie ....... oi. om
AX.

zo_._.<zhzuozo o ~.0

98

Even after 54 days, headspace 02 remained zero. Oxidation
should have occurred at this stage. The average 02
consumption rate (0-20 days), was 0.29 ml/day at 21°C and
1.2 m1/day at 41°C and 1.9 ml/day at 65°C. The value at
65°C was derived from the permeability study of the PVDC
coated PP/PE film, which utilized water saturated flow gas
(N2, 02) at 21°C and an elevated temperature of 65°C. This
corresponded to 10% RH at 65°C (Appendix 4). As RH of the
storage condition (45% RH) was higher than this the actual
consumption rate was probably higher than what was reported
here.

The generally accepted assumption with regard to
temperature dependence of product deterioration is that it

will follow the Arrhenius equation (Saguy and Karel, 1980)

K = K0 exp (-EA/RT) (19)

This formula is applicable to the data from the AOR (0-20
days). PVDC coated PP/PE packed without 0A. The activa-
tion energy (EA) calculated from formula (19) and Figure 27
was 10.1 Kcal/mol. The slope of the line (l/T°K Vs log AOC)

was -l/4.5 x 10-4. Calculation was conducted as follows:

K = Ko exp (~EA/RT)

1n k/K0 = -EA/RT

log K/Ko = -EA/2.3'RT

log K = log K0 - (EA/2'3 R) 1/T

slope = -(EA/2.3R) = -1/(4.5 x 10“)

99

Figure 27. Average 02 consumption rate (AOR, 0-20 days) as

a function of temperature for oat cereal packaged
in PVDC coated PP/PE and stored at medium
humidity in the dark, 21% initial headspace 02.

100

).
AOR .
'ml
(dTy')
10.0 ,-
\ 65°C
' x
41°C
1.0 :- x
E 21%:
X\
OJ 1 1 l n l L 1 4 #4 1 1 J

 

 

2.90 3.00 3.10 3.20 3.30 3.40

(-.-r-'-.T<-x10’) TEMPERATURE

101

3

R: 1.98 x 10’ Kcal/OK'mol

EA = 10.1 Kcal/mol

This value was in the lower range of that reported by Labuza (1972)
with regard to lipid oxidation (10-25 Kcal/mol). The M-TBA index was
different for storage at 21°C and 41°C without 0A (Figure 7-8). In
Table 15 is shown the statistical significance for oat cereal packaged
in PVDC coated PP/PE and stored at 21°C. The comparison of M-TBA index
for all three temperatures is shown in Figure 10. At 65°C M-TBA index
increased to 20 (0.0. x 100/gm) with and without 0A after 1-2 months
(Figure 9). At 65°C obvious browning occurred (visual only) after

1-2 months with and without 0A. Very severe off odors were noticeable.
The amount of 02 consumed correlated well with the results of sensory
evaluation (Table 5). Oxidation was observed when the amount of 02
consumed reached 30 ml. The exception was one sample packed at 80% RH
(41°C, 21% initial headspace 02). The M-TBA index was in general
agreement with sensory evaluation when it was applied to less than
extreme conditions. In normal conditions, oxidized change was observed
over 20 (0.0. x 100/gm) by sensory evaluation. In extreme conditions,
high RH (80% RH, 41°) and high temperature (65°C, 45% RH), the

M-TBA index did not correlate with sensory evaluation. For samples
stored at high RH (41°C, 80% RH) without 0A, the M-TBA index gave low
values even though oxidized odors were observed by sensory
evaluation. At 65°C, an increase in the M-TBA index (0.0. x
100/gm) occurred with and without 0A after 12 months.

Both samples had very severe off odors. The factors which

102

Figure 7. M-TBA index as a function of time for oat cereal
packaged in PVDC coated PP/PE under 21% initial
headspace 02 and stored at 21°C, 45% RH.

103

usages ......

83832.. .85...

d -

 

 

Illa 11111 @111

mz<o
8. om om oo 8 8 oo on 8 o. o

1 d d d .1 —

J

 

ON

on

O?

a
A1118 ......8 .

Om

xmoz_
<9... 2

0m

104

Figure 8. M-TBA index as a function of time for oat cerea1
packaged in PVDC coated PP/PE under 21% initial
headspace 02 and stored at 41°C, 40% RH.

105

m><o
8. om om 2. om 8 8 on 8 o. o

q - ¢

 

 

 

 

?
x ......... ..x/
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00.3.0 v
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1(36

Table 15

ANOVA for the Date of sanpling x Packaged condition ( 21°C. 45%RH.
PVDC coated PP / PE. 21% initial 02 concentration. with and without
02 absorber )

 

 

lean testing
source sun of squares d.f. square F ratio hypotheses
date
(Factor A) 90.7 3 30.2 16.3 significant
( 99% )
packaged
condition 73.5 1 73.5 39.7 significant
(Factor B) ( 99% )
Inter-
action 91.2 3 30.4 16.4 significant
A x B ( 99% )
Residual 44.4 24 1.9
Total 299.8 31

 

 

107

Figure 9. M-TBA index as a function of time for oat cereal
packaged in PVDC coated PP/PE under 21% initial
headspace 02 and stored at 65°C, 45% RH.

108

excess: 5:.

..Bcagac .85 ...

m><o
00. cm 00 on. om 0m 09 on ON 0

o

 

- d 1 d u u q d u

 

1.10.. IIIII 0.1....

 

l

j

on

O?

a
A1118 “8 v

Om

xwmz.
(m... 2

om

 

109

Figure 10. M-TBA index as a function of time for oat cerea1
packaged in PVDC coated PP/PE with 02 absorber,
21% initial headspace 02.

110

m><o
8. cm om 2. om on on on 8 o. o

. _

 

 

 

 

OT/ 1 0—
..ON
.on
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lll

influenced the TBA test were debated by several persons
(Dugan, 1955; Buttkus and Rose, 1972; Baumgartner, 1975).
Certain amines from protein degradation can condensate with
malonaldehyde, which can interfere with the TBA reaction.
At high temperature (65°C, 45% RH) and at high humidity
(41°C, 80% RH) browning related reactions can occur and
produce amines which consume malonaldehyde.

Oat lipids usually have only 0.5-5.0% double bonded
fatty acids (Hammond, 1983), which can form the condensa-
tion product (pigment) with malonaldehyde, however, appli-
cation of the M-TBA test to determine the oxidation of oat
cereal was in general agreement with sensory evaluation and
amount of 02 consumed at ambient condition. The M-TBA
index for products packed with GA in PVDC coated PP/PE was
less than 15 (0.D. x lOO/gm) in most conditions during the
whole storage period except at 65°C. The 02 concentration
in the headspace of packages packed with GA was maintained
at a minimal level for up to 2 months in most cases. The
use of 0A in delaying lipid oxidation was supported by the
M-TBA index at 41°C, 40% RH and sensory evaluation.

Absorbinngbilityiof the 0A

The absorbing capacity of the 0A was 160 ml/pouch in
ambient condition (Table 7, Figure 1), however, the water
activity inside the container influenced the absorbing

ability. Temperature could also affect absorbing ability.

112

When the water content inside the container is high, it
could absorb approximately 1000 ml/pouch. The DA consists
of iron powder, water, and catalysts. The exact reaction
with oxygen is not certain, however, the basic mechanism of
the reaction involves oxidation of the iron powder. When
there is an infinite supply of 02 and enough H20, iron
powder (Fe ) is oxidized to Fe3+. In this situation, one

mole Fe can theoretically absorb 3/4 mole 02 (Formula 8).
Fe + 3/4 02 + 3/2 H20-——+ Fe (0H)3 ———~

Fe20 3H20 (19)

3

Fe + 1/2 02 + H20 -—+ Fe (0H)2.__.
Fe (0H)2 + 1/4 02 + 1/2 H20 ——. Fe (0H)3 -—-
F9203 . 3H20

One gram iron is equivalent to 1/26 mole (molecular
weight of Fe = 26). At 21°C, volume of 1 mole gas is
22.4 x 103 (ml) x 294/273. Therefore absorbed 02 by 1 gm Fe
(at 27°C) =

22.4 x 103 x 294 x 3 =
273 x 4 x 26 696 (m])'

In actual use, the absorbing ability of the 0A in ambient
condition (21°C, 45% RH) was 33 ml per 1 gm absorbing
powder. This value was much smaller than its theoretical

value. Commercial 0A is manufactured to carefully regulate

113

its reaction speed without generating heat and hydrogen
during reaction. In ambient conditions, absorbing capacity

of the Fe powder was only partially used.

SUMMARY

The storage stability of a flaked oat cereal product
packed in Polyethylene (PE) and Polyvinylidene chloride
(PVDC) coated polypropylene (PP)/polyethylene (PE) with and
without oxygen absorber (0A) was evaluated.

0A reduced the oxidative deterioration in moderate
environments. The increase of the M-TBA index with GA was
smaller than that without 0A; however, in extreme conditions
of high temperature (65°C, 45% RH) and high relative humidity
(80% RH, 41°C 0A could not control deterioration. When 0A
was packed with product in low barrier material (PE), it
also was unable to prevent oxidation. A reasonable nitrogen
gas flush sample (1% initial headspace 02 concentration)
showed deterioration after one month, while 0A sample
prevented oxidative changes for up to three months.

Increased temperature and oxygen concentration, and
exposure to light accelerated the oxidative deterioration
for samples packed without CA as detected by headspace 02
change and sensory evaluation. This accelerating effect of
temperature and light was also observed with GA, however
this effect was reduced with GA. M-TBA index was generally
in good agreement with sensory evaluation and amount of 02

consumed except in extreme conditions.

114

115

The following conclusions are therefore, made:

Oxygen absorber (OA) reduces the oxidative deterioration
in moderate circumstances. The increase of the M-TBA
index with GA was smaller than that without 0A.

In extreme conditions; high temperature (65°C, 45% RH)
or high humidity (41°C, 80% RH), the OA loses its ability
to retain the deterioration.

In this experiment, a reasonable gas flushed sample (1%
initial headspace 02 concentration) showed deterioration
after 1 month, while the OA sample showed deterioration
after 3 months by sensory evaluation. This difference
of M-TBA index was significant at 99% level by analysis
of variance.
M-TBA index was in general, good agreement with sensory
evaluation and amount of 02 consumed except in extreme
conditions. Oxidative deterioration can occur when the
headspace 02 level is minimum (0.01%). Permeating
oxygen is competitively utilized by lipids and 0A.
High barrier package is necessary to utilize the ability
of OA.

Light accelerates the oxidation of oat cereal with and
without OA, observed by 02 amount of 02 consumed and

sensory evaluation.

APPENDICES

APPENDIX 1

DETERMINATION OF THE HEAD SPACE VOLUME
0F SAMPLE PACKAGES

Methodology

 

Head space volume of the package is measured by the

following procedures:

1.

Deposit the 50 g oat cereal into the plastic package.
Flush N2 into the package and regulate the total inner
volume t01255 ml by the same manner as for the storage
samples.

After, mix the pouch hard, measure the residual oxygen
concentration of the flushed package (Co) by the oxygen
analyzer. Sampling volume is 5 ml (Vs). Sampling times
are twice (n).

Insert 10 ml air (Va) into the package by an airtight
syringe.

After, blend the pouch vigorously, measure the new head
space oxygen concentration by the oxygen analyzer (C1).

Head space volume (V) is calculated by following

formula.

Co (V - nVs) + Va x 0.209

C1
(V - nVs) + Va

 

Va (0.209 - C1) + nVs (C1 - Co)
C'l-Co

 

116

V = origianl

117

head space volume (ml)

Va = volume of added air (ml)

C = residual
C] = final 02
Vs = sampling

residual

n = sampling

02 concentration (VOZ/Vtotal)
concentration (Voz/Vtotal)

volume for measurement for initial
oxygen (ml)

time of Vs

0.209 = 02 concentration in the air

Results

 

 

 

Co(V02/Vtotal) C1(V02/Vtotal) V (ml)
0.0115 0.0222 185
0.0150 0.0251 192
0.0104 0.0213 181
0.0113 0.0225 176
0.0196 0.0295 191

Ave. 185

Head space volume

of sample: 185 ml

118

Air composition (Tamamushi B, 1981)

 

Volume % Weight %
02 20.93 23.01
N2 78.10 75.51
Ar 0.9325 1.286
C02 0.03 0.04
We 0.0018 0.0012
He 0.0005 0.00007
Kripton 0.0001 0.0001
Xenon 0.000009 0.000009

 

119

APPENDIX 2

OXYGEN ANALYZER LC-7OO F(O) MANUFACTURED BY
TORAY ENGINEERING CO. LTD.

Principle of the Measurement

 

Zirconium solid electrolyte shows the 02' ion conduc-
tivity in high temperature. A solid electrolyte oxygen
concentration cell can be formed, when the electrodes are
fabricated in both sides of this electrolyte.

This cell produces a electromotive force, when the 02
partial pressure of each side is different. The electro—
motive force and ratio of oxygen pressure difference has a
relation called Nernst formula. When one side is
utilized as reference (air: 20.9% oxygen concentration),

sample gas concentration can be measured.
High 02 concentration side (reference)
02 + 4e —~ 202'

Low 02 concentration side (sample)

202' —- 02 + 4e

Nernst

En

En:

Pr:
Ps:

When T

120

formula

:0

_1 1n Pr

nF P?
electromotive force (V)
Faraday constant 96500 (J/V)
Gas constant 8.314 (J/mol-deg)
Absolute temperature (0K)
Partial pressure of reference gas (atm)
Partial pressure of sample gas (atm)

Charge numbers for ionization 4

700°C (9730K), Reference gas is air (Pr = 20.9)
48.26 10910 (20.9/Ps) (mV)

121

zirconium solid electrolyte

 

n. a,
0.. “A

P? e‘ ’02-\ '1 P5
02*? \oz-v' ~02

l——©__J electrode

 

 

 

 

 

  

- niwn Salide
electrolyte

    

Samrle 303
PS ~ - - W
Reference gas \

M" ’ Reference side

   

 

Pr electrode
Hedi-emotive
farce
E ('nvi 3‘”
20.9
E =4826103w Ps (mV)
200 .
100 >
/ 20. 9 7.

 

o a a a a a .
am can: 0.01 0.1 I IO 100

Sample side 02 concentration“)

P:

 

APPENDIX 3

MEASUREMENT OF THE LIGHT INTENSITY
IN THE EXPOSURE BOX

Methodology

 

Exposure box is fabricated using corrugate board, and
the size is 80 cm x 60 cm x 30 cm (L x W x H). Underneath
the top flap, a 15 W fluorescent light is attached. Light
intensity is measured by Gossen Pan Lux - Light meter. The
sensing device,which can be removed from the main body of
the light meter, is placed on the bottom of several different
points. Light intensity is directly measured by an analog

meter.

Results

Samples are placed inside the dotted line area (Figure
13) where light intensity ranged from 40 to 90 foot candles.
Samples are replaced and turned over each month in order to
average the effect of light exposure (conversion factor to

international unit):

10.764 lux = 1 foot candle

122

APPENDIX 4

CALCULATION OF PERCENT RELATIVE HUMIDITY
AT ELEVATED TEMPERATURES

Assume bubbler tubes produce gas at 100 percent rela-
tive humidity at bubbler temperature (iJL, room

temperature).

Wb = saturation vapour density in bubbler tube at bubbler

temperature.

AW = vapour density of diffuser cell calculated from

equation 1 below.

Tb = temperature of bubbler tubes (°K)

To = temperature of diffuser cell (0K)
Ws = saturation vapour density at diffusion cell
temperature.
Wc = Wb x (Tb/Tc) (Equation 1)

Percent Rela-
tive Humidity = WC/WS x 100 (Equation 2)

123

124

Qalsuletign

1. Tb = 21°C = 294°K
wb = 18.5 gm/m3 at Tb
TC = 41°C = 314°K
Ws = 54.1 gm/m3 at Tc

5:
II

C 18.5 x (294/314) = 17.3 gm/m3
Relative humidity = (17.3/54.1) x 100 = 323
32% RH at 41°C

Tb = 21°C = 2940K

Wb = 18.5 gm/m3 at Tb

To = 65°C = 338°K

ws = 161.3 gm/m3 at Tc

wC = 18.5 x (294/338) = 16.1 gm/m3

Relative humidity = (16.1/161.3) x 100 = 10%
10% RH at 65°C

APPENDIX 5

Calculation of the amount of 02 consumed and Average 0;
consumption Rate ( AOR. from t; to t, days ) at each condition

Calculation method
Change of headspace 02 concentration was a result of 0: consumption by the

cereal and permeated 0; from the outside.

Change of headspace 0: = O; permeated - 0: consumed
= Total headspace ( 185 ml ) t ( final 0; concentration -

initial 0: concentration ) (I)
t

02 permted = ipogch . f P (t) * dt (2)
0

Amount of O; consumed and AOR ( t; -t y days ) are showed by the formula
( 3 ) and ( 4 ).
t
0: consumed = Ppouch t I P (t) t dt - 185 t ( 0; conc.(t)- 0; conc.(0))
A ° (3)

Y

I 0: consumed J I
AOR ('11,; -t,. days ) -.- 1.x
‘ t” "*1 .V (4)

 

'125

'126

PPOuch : permeability constant of the pouch ( ml/pouch*day*atm )
P (t) : Pressure difference between outside and inside the package
at t days ( atm * ml/ml )
02 conc.(t) : headspace 0; concentration as a function of time ( ml/ml )
( final 02 concentration )
Oz conc.(O) : initial headspace 02 concentration ( ml/ml )

t?
I 02 consumed J : amount 02 consumed during certain time ( from t;

“ to t, days )
Here
P (t) = 0.209 - Oz conc.(t) (5)

0.209 : Outside concentration of 02 t 1 atm ( atm * ml/ml )

0: conc.(t) can be assumed to be a combination of the serial straight lines.

These lines are obtained as least squars regression lines.

When . 02 conc.(t)
0,§;t §=t1

O: conc.(t) an t + 0: conc.(O) (6)
am ..................

02 conc.(O)

 

\\\ Pu)
t; g t g t:
02 00110. (t) 82( I. - t1 ) '1' 02 6006. (h) (7) L\ -/

 

 

t.-. _f__t _<__t..

02 conc.(t) a.( t - tm-l ) + 02 CODC.(tm-l)

(8)
Here t; is a day when first straight line connects to second line. As the

same way t. is a day when n-lth line connects to n th line.

While t
02 consumed = fipouch * [I P (t) 3 dt - 185 t ( 0: conc.(t)- Oz conc.(0))

127

P (t) = 0.209 - 02 conc.(t) see (3)
Calculate the amount of 02 consumed in serial orders.
When
0 git g,t.

1. t
fivouch * I P (t) * dt = Fpouch * r ( 0.209 - 02 COllC. (t)) * ('11.

t
= "Ppouch a: I (0.209 - a.t - 0; conc.(0)) * dt
0

a
= Typouch ‘ [ ‘ 3: t2 ‘1’ (0.209 “ 02 600C. (0)) T t J (9)

185 t ( 02 conc.(t)- Oz conc.(0)) = 185 * ( alt + 02 conc.(O) - Oz conc.(0))
=185*(81t)

So __ a
o. consumed = PM... . t - i t’ + (0.209 - o. conc.(0)) 4 t J

(10)

-185* (art) (11)
When ‘

t. $.t $.tz

O; consumed = I 0; consumed ]:'+ E 0; consumed J:l (12)

I 0; consumed 1‘ = -§pouch * (1‘ P (t) t dt - 185 t ( 0; conc.(t)- 0; conc.(t.))
ti 1.] (13)

t
Fmouch * f P (t) * (11.

t1

_ t.
Ppouch * ‘ftf 0.209 - azt + aztn- 02 conc.(t.)) t dt

_. 32
9...... 4 I - ? t’ + (0.209 + am- 0. when.» . t 1; (14)

'128

185 t ( Oz conc.(t)- 02 conc.(ti))

185 t ( a:( t - t. ) + 02 conc.(t.) - 02 conc.(ti))

185 * ( az( t - t1 )) (15)
I

t
[ 0; consumed 10 is calculated from the formula (11).

From (13): (14): and (15)

a
[02 consumed J:=1$p°uu‘ * [- —2—2 t: + (0.209 '1' 8214- 02 conc.(ti)) II t 3:}
'185*‘a’("" )1 (16)

a
(' ‘2—2 t2 + (0.209 + azti- 0: cont. (1:1)) * t J;

 

 

 

 

a

. - 2’ 4 ( t’ - i. ) 4.10.209. a.t.- 0.66.6410): (t- t.)
a

.- '.(t=-h>+an.4(i-h)+(cam-o.mmxh»:<i-t.>
a: z

= - t ( t - ti ) + ( 0.209 - 02 conc.(ti)) * ( t - ti ) (17)

So 0: consumed
— a .
= Ppouch ‘ t“ z * ( t ’ t! )2+ (0.209 " 0! conc.(tl)) * ( t - t1) )
- 185 t ( a:( t - t! )) + ( 02 consumed ):t See (12).(16). and (17)

By the same way

tn-l ététa

02 consumed
an

 

= “fipomch * L’

4 ( t - t.-. )'+ ( 0.209 - o. conc.(tn-i)) . ( t - 1.-.);

- 185 t ( an( t - t m-l )) + I 0; consumed J tn-'

'129
Calculation of each condition

1. 41°C. 40%RH. no Ozabsorber. PVDC coated PP / PE. 21% initial headspace
Ozconcentration

02 consumed = Ppouch * (LI P (t) t dt - 185 t ( 02 conc.(t)- Oz conc.(0))

 

 

 

I 02 consumed 1 ty
AOR ( tx 'ty days ) = tx
( t, -tx )
_. 81
02 consumed = Ppouch * t ’ "2_ t2 '1 ( 0.209 " 02 Corie. (0)) t t J
- 185 t ( ant ) 0; conc.(t)
-§pouch = 1.62 ( ml / pouch * day I atm ) 0.209
O; conc.(O) """""""
0 §,t g 35.1
Pa)
8. = - 0.00588
02 conc.(t) = - 0.00588t + 0.206 ( atm * ml / ml )
0.00588
02 consumed = 1.62 t ( _——_2-——- t2 + 0.003t ) 0 35.1
I
( day )

+ 185 t 0.00588 * t
= 0.00471;2 + 1.09t ( ml )

 

When 0; consumed ( ml )
t = 10 0.47 + 10.9 911.4
t = 20 1.88 + 21.2 = 23.1
t = 35.1 5.79 + 38.3 = 44.1
35.1 §,t
02 conc.(t) = 0
0: consumed
= -§pomch * I- :2 t ( t - t. )z+ ( 0.209 - O; conc.(t;)) * ( t - ti ) )

-1854=(a:z(t-1::))+I02consumedJ;i
a; = 0 , Oz CODC.(t1) = 0 a ti = 35.1

.130
So
02 consumed
= 1.62 4 0.209 4 < t - 35.1 ) + 1 oz consumed J :
=0%9*(t-%J)+440

5.1

 

When Oz consumed
t = 50 5.1 + 44.0 = 49.1
t = 90 18.6 + 44.0 = 62.6
t!
I 02 consumed J
AOR ( tx ‘ty days ) = “ ( ml / day )
( t, -tx )
23.1
AOR ( 0 - 20 days ) = --- = 1.2
20
49.1-23.1
AOR ( 20 - 50 days ) = ------ = 0.87
. 30 .
62.6-49.1
AOR ( 50 - 90 days ) = --;a--- = 0.34

2. 41°C. 40%RH. no Ozabsorber. PVDC coated PP / PB. light exposure.
21% initial headspace 02 concentration

 

 

02 cone. (1.)
Fpouch = 1.62 ( l1 / DOUCII * day * at. ) 0.209 .-------_-_-_--
0: 0011C. (0)
0,3 t 5.22.0
PM
a: = 0.00928
0: conc.(t) = - 0.00928t + 0.204 ( atm t ml / ml )
4 0.00928
02 consumed = 1.62 t ( --;--'t' + 0.005t ) 0 22.0
t
( day l!

+ 185 * 0.00928 * t
= 0.00752t2 + 1.73t

131

When 02 consumed
t = 5 0.19 + 8.65 = 8.84
t = 10 0.75 f 17.3 = 18.1
t = 20 3.0 + 34.6 = 3716
t = 22 3.6 + 38.0 = 41.6
22.0 §_t
02 consumed

=1.62*0.209*(t-22.0)+IOzconsumed1:
= 0.339 * ( t - 22.0 ) + 41.6

 

 

When 02 consumed
t = 50 9.5 + 41.6 = 51.1
t = 90 23.1 + 41.6 = 64.7
37.6
AOR ( 0 - 20 days ) = ---'= 1.9
20
51.1-37.6
AOR ( 20 - 50 days ) = = 0.45
30
64.7-51.1
AOR ( 50 - 90 days ) = = 0.34

40

3. 41°C. 40%RH. no Ozabsorber. PVDC coated PP / PE.
5% initial headspace 02 concentration
ipouch = 1.62 ( 1111 / DOUCh * day t at” ) 0.209
0 g t g 58.5
a: = 0.00084
0: conc. (0)
02 conc.(t) = - 0.00084t + 0.049 ( atm t ml / ml )

02 COHC. (t)

-------_-—---

 

 

'132

0.00084
02 consumed = 1.62 * ( -——-—-— t2 + 0.16t )
2
+ 185 * 0.00084 * t

= 0.00068t‘ + 0.414t

When 0: consumed
t = 10 0.68 + 4.14 = 4.21
t = 20 0.27 + 8.28 = 8.55
t = 50 1.7 + 20.7 = 22.4
t = 58.5 2.3 + 24.2 = 26.5
58.5 g t
O; consumed

= 1.62 t 0.209 t ( t - 58.5 ) + I 02 consumed ] o
= 0.339 t ( t - 58.5 ) + 26.5
When 0; consumed
t = 90 10.6 + 26.5 = 37.1
37.6
AOR ( O - 20 days ) = --- = 1.9
20
51.1-37.6
AOR(20-50days)=—3o——=O.45

64.7-51.1
AOR ( 50 - 90 days ) = "-1i;-—-'= 0.34

4. 41°C. 40%RH. no Ozabsorber. PVDC coated PP / PE. 1% initial headspace
Ozconcentration

__ a
02 consumed = Ppouch * I - -51 t2 + ( 0.209 - 0: conc.(0)) t t )

~185*(ait)

13...... = 1.62 ( .1 / pouch . day . atm )

'133

 

 

 

0 _$_ t g 12.6 02 conc. (t)
a; = 0.00043 0.209 L--% ---------
02 conc.(O)
02 conc.(t) = - 0.00043t + 0.009 ( atm * m1 / ml ) PM)
- _ 0.00043
02 consumed = 1.62 t ( - ----- t2 + 0.20t )
2 1. PW
0909 5”,
- 185 * 0.00043 * t
=- 0.00035t2 + 0.244t 0 12.6 59
t j t:
When 0; consumed I I day )
t = 10 - 0.04 + 2.44 = 2.40
= 12.6 - 0.06 + 3.07 = 3.01

126$t§59
a: = - 0.000318, 02 conc.(tx) =0.0145

t. = 12.6
0: conc.(t) : a; c ( t - t. ) + 0: conc.(t.)
02 consumed
= .fipouch * I- a: t ( t - t. )z+ ( 0.209 - 02 conc.(t1)) * ( t 4 t1 ) )

 

- 185 t ( a;( t - t1 )) + I 02 consumed ):‘

0.000318

=1.62*I *(t-12.6)z+(0.209-0.0145)*(t-12.6))

 

.6

2
+ 185 .. 0.000318 . < t - 12.6) + (o. consumed 1:

0.000318

= 1.62 . . (t ~12.6)z+ 0.195 . ( t -12.6)J

 

+ 0.0588 * ( t - 12.6 ) + 3.01

When 0; consumed
t = 20 5.80
t = 50 17.4

t = 59 20.8

'134

59 $.t

02 consumed

59

= 1.62 * 0.209 * ( t - 59 ) + I 02 consumed )o
= 0.339 * ( t - 59 ) + 20.8
When 02 consumed

t = 90 10.5 + 20.8 = 31.3

5.8
AOR ( 0 - 20 days ) = --- = 0.29

20

17.4—5.8
AOR ( 20 - 50 days ) = = 0.39

30

31.3-17.4
AOR ( 50 - 90 days ) = = 0.35

40

 

 

5. 21°C. 45%RH. no Ozabsorber. PVDC coated PP / PE
21% initial headspace 0; concentration

'Ppoueh = 0.189 ( ml / pouch * day * atm ) 0.209
0 02 conc.(O)
5It

an = - 0.0016
02 conc.(t) = - 0.0016t + 0.200 ( atm * ml / ml )

0.0016
02 consumed = 0.189 * ( -_-_1;_—_- t2 + 0.009t )

+ 185 * 0.0016 * t
= 0.000151tz + 0.298t

02 conc. (t)

 

 

0

90

'135

When 02 consumed When 02 consumed

 

 

t = 10 3.0 t = 50 12.2
t = 20 6.0 t = 60 15.3
t = 40 12.2 t = 90 2&0
6.0
AOR ( 0 - 20 days ) =. ---'= 0.30
20
15.3-6.0
AOR ( 20 - 50 days ) = = 0.31
30
28.0-15.3
AOR ( 50 - 90 days ) = 40 = 0.32

6. 41°C. 80%RH. no Ozabsorber. PVDC coated PP / PE. 21% initial headspace
Ozconcentration

_. a
0: consumed = Ppouch * I - ---l-tz + ( 0.209 - 0: conc.(0)) * t J
2

 

 

 

- 185 t ( ait ) ‘ 0; conc. (t)
-Fpouch = 1.62 ( m1 / pouch * day 1 atm ) ‘ 0.209 L _______ __
O; conc.(O) ’ b
0 _<__ t S 46.5
PM)
a: = - 0.00331
0.048
02 conc.(t) = - 0.0033lt + 0.202 ( atm * ml / ml ) V
0.00331
0: consumed = 1.62 * ( - _—__2—__— t2 + 0.007t ) 0 46.5
t:
(day)
+ 185 9 0.00331 * t
= 0.00268tz + 0.605t ,
When 02 consumed When 02 consumed
t = 10 6.3 t = 40 28.5

t = 20 13.2 t = 46.5 33.9

1136

46.5 g t
82 = - 0.000536. 02 conc.(ti) =0.048
t. = 46.5 '

02 conc.(t) = 82 * ( t - t1 ) + 02 conc.(t.)

02 consumed
a
z 4 ( 1 - t. )'+ < 0.209 - oz conc.(t1)) 4 ( 1 - t1 ) J

 

= -Ppomch * I‘

- 185 4 ( a:( t - t1 )) + 1 0: consumed J:'

0.000536

= 1.62 4 I 4 c t - 46.5 )'+ ( 0 209 - 0.048 ) 4 ( t - 46.5 )J

 

+1m4oomm64(i-ms)+(o.mmmm fi‘

0.000536

4 1.62 4 4 < t - 46.5 J'+ 0.161 4 ( 1 - 46.5 )J

 

+0.0992¥(t-12.6)+33.9

When 02 consumed
50 35.2
67 41.3
90 50.4

t

a-
II

t

13.2
AOR ( 0 - 20 days ) = -;a—- = 0.66

35.2 - 13.2
AOR ( 20 - 50 days ) = 30 = 0.73

 

50.4 - 35.2
AOR ( 50 - 90 days ) = 4b = 0.35

 

1137

 

 

7. 65°C. 45%RH. no Ozabsorber, PVDC coated PP / PE. 21% initial headspace
0; concentration
.. 31
02 consumed = Ppouch * I - t2 + ( 0.
’185* (816)
.Fpouch = 10.8 ( ml / p0uch * day t atm )
Dig t g 4.1
81= - 0.0358
02 conc.(t) = - 0.0358t + 0.209 ( atm * ml
0.0358
02 consumed = 10.8 * ( - 2 t2 )

_+ 185 * 0.0358 4 t
=-0.191t’ + 6.62t

When 0; consumed
t = 2.0 0.76 + 13.2 = 14.0
t = 4.1 3.2 + 27.1 = 30.4

4.1gt365.4
823-04000640
t1 = 4.1
0: consumed
0.00064
= 10.8 t I ‘-§-——'-

02 conc.(ti) = 0.064

2
4 ( t - 4.1 ) +

+ 185 * 0.00064 * ( t - 4.1 ) + I O: consumed 1:.

0.00064

= 10.8 4 I

+ 0.118 4 ( t — 4.1 ) + 30.4

 

 

209 - 02 conc.(0)) m t J
0: conc.(t)
0.209
0: conc.(O) ---------------
/ ml )
P81
0.0064
0.025
4.1 55.4
t1 I day ) t,

( 0.209 - 0.064 ) 4 ( t - 4.1 )J

4 ( t - 4.1 12 + 0.145 4 ( 1 - 4.1 )1

When 0; consumed When 02 consumed
t = 20 58.0 t = 65.4 146
t = 50 115 t = 44 103

'138
65.4 g t
as = 0.00321 . 02 conc.(tz) = 0.025
t2 = 65.4
02 consumed
0.00321 2
= 10.8 4 I - --E;---* ( t - 65.4 ) + ( 0.209 - 0.025 ) t ( t - 65.4 )

.4

65
- 185 * 0.00321 * I t - 65.4 ) + I 02 consumed ) 0

0.00321 2
=10.8* I-—2—-*(t-65.4) +0.206*(t-65.4))

+ 0.594 t ( t - 65.4 ) + 146

 

When 02 consumed When 0: consumed
t = 75 161 t = 90 176
t = 85 172
AOR ( 0 - 20 days ) = --;--= 2.9
20
115 - 58
AOR ( 20 - 50 days ) = = 2.9
30
176 - 115
AOR ( 50 - 90 days ) = --E;;--'= 1.9

. 45°C. 40%RH, no Ozabsorber. PE. 21% initial headspace 02 concentration

 

a
02 consumed = Enough t I - ‘ t3 + ( 0.209 - 02 conc.(0)) * t 1
- 185 * I 811 ) .
‘fimoucb = 220 ( ml / pouch * day * atm )

Ogt§l4.0
31 = - 0.00021

'139

 

 

 

 

02 conc.(t) = - 0.00021t + 0.209 ( atm * ml / ml )
0.00021
02 consumed = 220 t ( - t2 )
2 02 conc.(t)
'1‘ 185 * 0.00021 * t 0.209 1P“)
0: CORC. (0)
= 0.023t’ + 0.039t 0.208
' 0.186
When 02 consumed
t = 14 5.1
14 §:t $.28 t
‘ M m m 90
a2 = - 0.00143 4 02 conc.(t1 = 0.206 t: t: to to
l ( day )
t1 = 14
02 consumed '
0.00143 2
= 220 t I * ( t - 14 ) + ( 0.209 - 0.206 ) * ( t - l4 ))

+1m400mm4(1-14J+10.mmum fl“

0.00143

4&04( 4(1-14f400m4(t-1ln

+0.265*(t-14)+5.1

When 02 consumed
t = 20 16.3
t = 28 48.9

28 g t g 58
a; = 0.00067 . 0; conc.(tz) = 48.9
t; = 28

02 consumed

= 220* I- 0.00067 *(t-28)z+(0.209—L0.186)t(t-28)

2.
- 185 * 0.00067 * ( t - 28 ) + I 02 consumed J o

 

'140

0.00067 2
= 220 * I - --;;--- t ( t - 28 ) + 0.023 * ( t - 28 ))

- 0.124 t ( t - 28 ) + 48.9

When , 02 consumed When 02 consumed
t = 38 106 - t = 58 131
t = 50 122

58gtg90
a. = - 0.000067. 02 conc.(ts) = 131
to = 58

Oz consumed
' 0 000067

220 4 I -—l—§————— 4 ( t - 58 J2 + ( 0.209 - 0.206 ) 4 ( t - 58 J

+ 185 4 0.000067 * ( t - 58 ) + I 0: consumed )5:

0.000067 2
220 t I - --2;—'-- t ( t - 58 ) + 0.003 * ( t - 58 ))
+ 0.0124 4 ( 1 - 58 1 + 131
When 0: consumed

t = 90 135

16.3
20
122 - 16.3

AOR ( 0 - 20 days ) =

 

= 0.82

“OR I 20;— 50 days ) =

 

= 3.5

30

135 - 122
AOR(50-90days)= T=0.34

 

APPENDIX 6

Calculation of the amount of permeated 02 by iterative way

Calculation method

Amount of permeated 0: changes depending upon the pressure difference

between outside and inside the package. This pressure difference is influenced

by the package headspace. time. and permeability of the package material.

In this calculation. 0: absobed by the packaged product is ignored, however

this calculation is only used at the time when the product is assumed to consume

little amount of 0:.

Pressure difference is assumed not to change during 1 hour. Calculation

is iterated in one hour.

First 1 hour

0.209 ( atm * m1 / ml )

 

HeadspaceOz is 0%
when 0; absorber
lost its ability.

0%

 

 

 

Vo

A: = 0.209 *.§ pouch

 

Second 1 hour
01 ..

Az=(0.209- )‘Ppouch
V0

Third 1 hour
“1+8: __

A: = I 0.209 ‘ ) * P vouch

V0

141

 

0.209 ( atm * ml / ml )

HeadspaceOz is 0%
when 02 absorber
lost its ability.

0%

 

 

 

V0

'142

N th 1 hour

A; + A; + - - - A.-. __
An = ( 0.209 ’ ) * P pouch
Vo

 

So the amount of 02 permeated during N hours is
21A.

02 percentage inside the pouch at N hours
later
I: Am

Vo

 

V. ; headspace
_ I ml )
Ppouch
: permeability
of the pouch
( ml / pouch 8 hour 4 atm )
A. : amount of 0: permeated from N-l
to N hours ( ml )
0.209 : outside 0: partial pressure
( atm * m1 / ml )

Calculation for permeated 0: amount of PE pouched sample after 0; absorber
lost its ability ( 41°C. 40%RH, PE. 21% initial headspace 0; )

Here V.

= 185 ( ml )

-Fpouch = 9.17 ( ml / pouch * hour 3 atm )

 

 

 

 

 

A; + A: + - - + Aa-i 01 + A: + - + Am-l __
hours A. = ( 0.209 - ) * Ppouch
Vo V0

1 0 1.92

2 0.0104 1.82

3 0.0202 1.73

4 0.0296 1.65

5 0.0385 1.57

6 0.0470 1.49

7 0.0550 1.41

8 0.0626 1.34

9 0.0699 1.28

10 0.0718 1.21

 

143

 

 

 

 

 

An+Az+--+An-n A1+Az+-+A..-. _
hours An = ( 0.209 " ) * Ppouch
V0 V0
11 0.0833 1.15
12 0.0895 1.10
13 0.0918 1.07
14 0.0976 1.02
15 0.103 0.971
16 0.108 0.924
17 0.113 0.880
18 0.118 0.837
19 0.123 0.793
20 0.127 0.749
21 0.131 0.715
22 0.135 0.680
23 0.139 0.645
24 0.142 0.610
25 0.145 0.584
26 0.148 0.558
27 0.151 0.532
28 0.154 0.505
29 0.157 0.479
30 0.160 0.453
31 0.162 0.427
32 0.164 0.410
33 0.166 0.392
34 0.168 0.375
35 - -
36 - -
37 - -
2 Au ( hours ) ; 29.1 ml —— 15.7% headspace 0;

BIBLIOGRAPHY

BIBLIOGRAPHY

Baumgartner, N.A., Baker, N., Hill, V.A. and Wright, E.T.
1975. Novel Interface in Thiobarbituric Acid Assay for
Lipid Peroxidation. Lipids 10:309.

Berlin, E. and Pallansch, M.J. 1963. Influence of Drying
Methods on Density and Porosity of Milk Powder Granules.
Journal of Dairy Science 46:8.

Brinkmann, G. and Schlebusch, L. l953. West German Patent
869,042. See Saito's Paper, #30.

Buttkus, H. and Rose, R.J. 1972. Journal of American Oil
Chemical Society 50:387.

Caldwell, E.F. and Grogg. B. 1955. Application of the
Thiobarbituric Acid Test to Cereal and Baked Products.
Food Technology 9:185.

Dahle, L.K., Hill, E.G. and Holman, R.T. l962. Arch.
Biochem. Biophys. 98:253.

Dehghan, M. l979. The Relative Composition and Distribu-
tion of the Lipids in Six Common Oat Varieties and
Commercial Flour. M.S. Thesis. Iowa State University,
Ames.

Dugan, Jr., L.R. l955. Stability and Rancidity. Journal
American Oil Chemical Society 32:605.

Farmer, E.H. and Sutton, D.A. 1943. Journal Oil Chemical
Society ll9.

Frey, K.J. and Hammond, E.G. 1975. Journal American Oil
Chemical Society 52:358.

Forsberg, R.A., Youngs, V.L. and Shands, H.L. 1974. Crop
Science l4:221.

Fujishima, D. 1977. Japan Patent No. 19:729 Found in
Saito's paper, #30.

144

145

Hammond, E.G. 1983. Lipids in Cereal Technology.
Academic Press, London. pp. 331-351.

Isherwood, F.A. 1943. United Kingdom Patent No. 553991
found in Saito's paper, #30.

Labuza, T.P. 1972. Oxygen Scavenging System for Flexible
Packaging of Whole Dry Milk. CRC Critical Review of
Food Technology 3(2):217.

Lindberg, P., Bingefors, S., Lannek, N. and Tanhuanpaa, E.
1964. Acta Agri. Scand. 14:3.

Loo, C.C. and Jackson, N.P. 1958. United States Patent No.
2,825,651. Found in Saito's paper, #30.

Maloney, J.F., Labuza, T.P., Wallace, D.H. and Karel, M.
1966. Autooxidation of Methyl Linoleate in Freeze-dried
Model Systems. 1. Effect of Water on the Autocatalyzed
Oxidation. Journal of Food Science 31:878.

Marcuse, R. and Johansson, L. 1973. Studies on the TBA
Test for Rancidity Grading; II. TBA Reactivity on
Different Aldehyde Classes. Journal of the American
Oil Chemical Society 50:387.

Maude, A.H., Rodman, C.J., Styer, C.A. and Wilharm, N.C.
1925. United Kingdom Patent No. 226512, found in Saito's
paper, #30.

Mucha, T.J., Pallansch, N.J., Patterson, v.1. and Tamsma, A.
1961. Factors Related to the F1avor Stability of Foam-
dried Whole Milk. Journal of Dairy Science 44:91.

Pan, v.9. 1983. A Rapid Method for Stereospecific Glyceride
Analysis and It's Application to Soybean and Oat
Varieties. Ph.D. Dissertation. Iowa State University,
Ames.

Patton, S. 1974. Malonaldehyde, Lipid Oxidation, and the
Thiobarbituric Acid Test. Journal of the American Oil
Chemical Society 51:114.

Pokorny, J., Zeman, I. and Jancek, G. 1961. Sb Vy. Sk.
Chem. Tech. Praze Potravny 5-l:351. Found in Hammond,
#13.

Price, P.B. and Parsons, J.G. 1975. Journal of the American
Oil Chemical Society 52:490.

146

Quast, D.G., Karel, M. and Rand, N.M. 1972. Development
of a Mathematical Model for Oxidation of Potato Chips
as a Function of Oxygen Pressure, Extent of Oxidation
and Equilibrium Relative Humidity. Journal of Food
Science 37:673.

Roche, de la, I.A., Burrows, V.D. and McKenzie, R.I.H.
1977. Crop Science 17:145, found in Hammond, #13.

Saguy, I. and Karel, M. 1980. Modeling of Quality Deteri-
oration During Food Processing and Storage. Food
Technology 2:78.

Sahasrabudhe, M.R. 1979. Journal American Oil Chemical
Society 67:80.

Saito, M. 1979. Food Quality Preservation by Means of
Free-Oxy en Absorber, Shokuhin to Kogyo. (Food and
Industry? May 2nd, Vol. 65.

Sidwell, C.G., Salwin, H., Benca, M. and Mitchel, Jr., J.H.
1954. The Use of Thiobarbituric Acid as a Measurement
of Fat Oxydation. Journa1 of the American Oil Chemical
Society 31:603.

Singh, R.P., Heldman, D.R., and Kirk, J.R. 1974. Computer
Simulation of Quality Degradation in Liquid Foods During
Storage. Proceedings of the Fourth International
Congress on Food Science and Technology 4:407.

Sinnhuber, R.O., Yu, T.C. and Chang, Y.T. 1958. Food
Res. 23:626.

Tamamushi, B. 1981. Rikagaku-ziten (Iwanamishoten, Tokyo),
p. 345.

Uematsu, T. and Someya, M. 1978. Hoosoogijutsu ni Yoru
Aburagashi no Sanka.Booshi (Protective Methods of Lipid
Oxydation for Oily Food by Hay of Package Technology.
Japan Food Sciencfe 1:58.

Vyneke, w. 1975. Evaluation of the Direct Thiobarbituric
Acid Extraction Method for Determining Oxidation
Rancidity in Mackeral (Scomber scombrus L). Fette
Seiten Anstrichen. 77:239.

Nelch, R.N. 1975. Journal Science Fond Agriculture 26:
429. Found in Hammond, #13.

147

Youngs, V.L. and Puskulcu, H. 1976. Cr0p Science 16:881.
Found in Hammond, #13.

Zimmerman, P.L., Ernst, L.J. and Ossian, w.F. 1974.
Scavenger Pouch Protects Oxygen Sensitive Foods. Food
Technology 8:63.

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