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1 LIBRARY
Michigan State
L University

 

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This is to certify that the

thesis entitled

Thermally Induced Migration Of Food
Packaging Materials Into Foods During
Microwave Heating

presented by

Siti Noorbaiyah Abdul Malek

has been accepted towards fulfillment
of the requirements for

Masters degree in Food Science

MMW‘

Major #ofessor

 

 

Date 7/2/90

0-7639 MS U is an Affirmative Action/Equal Opportunity Institution

 

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PLACE IN RETURN BOX to remove this checkout from your record.
TO AVOID FINES return on or before date due.

 

 

DATE DUE DATE DUE DATE DUE I

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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MSU I: An Affirmdive Action/Equal Opportunity Institution
cWMG-DJ

 

 

 

 

THERMALLY INDUCED MIGRATION OF FOOD PACKAGING MATERIALS
INTO FOODS DURING MICROWAVE HEATING

By

Siti Noorbaiyah Abdul Malek

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

MASTER OF SCIENCE
in
Food Science

Department of Food Science and Human Nutrition

1990

ii

ABSTRACT

THERMALLY INDUCED MIGRATION OF FOOD PACKAGING MATERIALS
FOODS DURING MICROWAVE HEATING

By
Siti Noorbaiyah Abdul Malek

The effect of temperature at the interface of two microwaveable containers (a
susceptor material and a CPET laminated tray) on the migration of four compounds were
studied using the method proposed by the Food and Drug Administration (FDA). Corn
oil was used as a food simulant, and was microwaved for 1 to 7 minutes in both
containers. The temperature at the interface of the oil and the containers were recorded.
Extracts of the oil were then analyzed by a HPLC system.

Temperatures at the interface of the susceptor material increased 3 to 4 times faster
than in the CPET tray under identical exposure times. The highest temperatures attained
in the susceptor material after 1 to 7 minutes of exposure were 136.4°C, 186.0°C,
196.6°C, 205.4’C, 217.8°C, 225.0°c, and 244.8°C, respectively. The highest temperatures
attained in the CPET tray were 34.1°C, 45.8° , 59.9°C, 73.6°C, 78.9°C, 756°C, and
819°C, respectively.

Dimethyl terephthalate (DMT), diethyl terepthalate (DET), bis-(Z-hydroxyethyl)

terephthalate (BI-IET), and polyethylene terephthalate cyclic trimer were all found to have
migrated into the oil heated in the susceptor material. No migration was observed in the
oil heated in the CPET tray. The concentration of all components increased with
temperature at the interface. The highest concentration of BHET, DMT, DET, and
Cyclic Trimer were 41.9 ug/dm’. 361.5 ug/dm’, 343.6 ug/dm’, and 12300 ug/dm’,
respectively.

iv

To Ikmal, Fariz, Apak, and Mummy

ACKNOWLEDGEMENTS

IN THE NAME OF ALLAH, THE MOST MERCIF UL AND
THE MOST BENEFICIENT

Alhamdullilah (Praise be to Allah). Lord of the Universe. The mercy-giving, The
Merciful! Ruler on the Day of Repayment, You do we worship and You do we call on
for help. Guide us along the straight road, the road of those whom You have favored,
with whom You are not angry, nor who are lost. [Amen]

I would like to extend my gratitude to my sponsors, the Government of Malaysia
and the MARA Institute of Technology, for giving me this valuable opportunity to further
my studies here in the United States of America I hope I have fulfilled the trust and
hope that they put in me to gain knowledge in order to help fulfill the dreams of
betterment of our people and country.

’Terima kasih banyak-banyak’ to my major professor, Dr. Robert Ofoli for all the
unselfish advice. help, guidance, kind thoughts and pep talks given timing the duration of
my program. I am also indebted to him and his family for their assistance and
understanding through some of the difficult times that I went through during my stay
here.

My appreciation also goes to my guidance committee, Dr. Carol Sawyer, for giving
me the idea of what project I should pursue; Dr. Bruce Harte. for supplying the materials
for my study; Dr. Jack Giacin, for agreeing to replace Dr. Jim Steffe (who is on

sabbatical leave at the University of California, Davis) as my committee member. I am
also grateful to Dr. Giacin for allowing me to use the HPLC system and Infra-red
Spectrophotometer, and also helping in the anlaysis my HPLC data.

My profound thanks to Dr. Heidi Hoojat for all her help and for brainstorming with
me to get the experiment and equipment running. She saved me time and energy and also
blessed me with her companionship throughout the long hours spent in the laboratory.

Many thanks also to Joe Esch, who patiently helped me in getting the materials, and
designing (and redesigning!) the migration cell, and Jon Morrison who helped are run the
microwave experiments and extraction procedures.

My sincere thanks to all my friends, especially Vance, Su-Der, Danny, Pandey,
Kevin, Tom, and Brian for all their help and suggestions and for helping make my stay
here a memorable one. I hope that you will remember me and that one day in the future
we will meet again.

A special thank you to my beloved husband and family for their understanding and

patience all these years.

 

 

 

 

 

 

 

TABLE OF CONTENTS
LIST OF TABLES x
LIST OF FIGURES - xi
CHAPTER 1 INTRODUCTION AND OBJECTIVES .................................... 1
CHAPTER 2 LITERATURE REVIEW ........................................................... 5
2.1 Introduction ................................................................................................. 5
2.2 Microwave Heating ..................................................................................... 5
2.2.1 Microwave radiation ........................................................................... 5
2.2.2 Dielectric Constants and the Loss Tangent ........................................ 9
2.3 Types of Microwave Packages .................................................................. 10
2.3.1 Transparent Materials ......................................................................... 10
2.3.2 Absorbing Materials ........................................................................... 10
2.3.3 Shielding Materials ............................................................................. 11
2.3.4 Field Intensifying Materials ................................................................ 13
2.4 Migration of Packaging Components ........................................................ 16
2.4.1 Introduction ......................................................................................... 16
2.4.2 Global and Specific Migration ............................................................ 16
2.4.3 Direct and Indirect Additives .............................................................. 17
2.4.4 Theoretical Considerations ................................................................. 17
2.4.4.1 Mass Transfer in Polymeric Films ............................................. 17
2.4.5 Review of Migration Studies ...... - - - - 21
CHAPTER 3 MATERIALS AND METHOD - -- - ......... 26
3.1 InU'OdIICtiOII -- - ---------------- - ~:‘=:v - - - .- ‘2 ““ ‘ .................... : 26
3.2 Experimental Design - - ...... - ----------- . .......... 26
3.3 Samples and Materials - - 28
3.4 Verification of Materials Used ................................................................... 30

3.5 Microwave Exposure ...... ............................... 31

 

 

 

 

 

 

 

 

 

3.6 Extraction Procedure .................................................................................. 34
3.7 High Pressure Liquid Chromatography (HPLC) Analysis ........................ 34
3.8 Preparation of Calibration Curves _____ 55
CHAPTER 4 RESULTS AND DISCUSSIONS ................................................ 36
4.1 Material Verification - - .......... 36
4.2 Microwave Exposure ...... - _ ...... - 36
4. 2. 1 Exposure Time versus Temperanne ................................................... 36
4. 2. 2 E t of Temperature on Susceptor Material .................................... 48
4. 3 Analysis of migrants by HPLC. .................................................................. 50
4.3.1 Standard Curves ............................................................................... 50
4. 3. 2 Percent Recovery of Standards. .......................................................... 51
4.3.3 Sample Analysis ................................................................................. 54
4.3.4 Concentration of DMT, DET, BI-IET and Cyclic Trimer ................... 60
CHAPTER 5 SUMMARY AND CONCLUSIONS .......................................... 66
CHAPTER 6 SUGGESTIONS FOR FURTHER RESEARCH ...................... 70
CHAPTER ‘7 LIST OF REFERENCES ............................................................ 71
APPENDICES
APPENDIX Al. Average temperature of corn oil heated in susceptor
material for one minute. 76
APPENDIX A2. Average temperature of corn oil heated in susceptor
material for two minutes. _ 77
APPENDIX A3. Average temperature of corn oil beated' Iii susceptor
material for three minutes. - - -- ...... - 79
APPENDIX A4. Average temperature of corn oil heated in susceptor
material for four minutes. - - 82
APPENDIX AS. Average temperature of corn oil heated in susceptor
material for five minutes. 85
APPENDIX A6. Average temperature of corn oil heated in susceptor
material for six minutes. 89

 

APPENDIX A7. Average temperature of corn oil heated in susceptor
material for seven minutes.

-94

 

APPENDIX A8. Average temperature of corn oil heated in CPET tray for
one minute.

 

APPENDIX A9. Average temperature of corn oil heated in CPET tray for
two minutes. - 100

APPENDIX A10. Average temperature of corn oil heated in CPET tray for
two minutes. 101

APPENDIX All. Average temperature of corn oil heated in CPET tray for
two minutes. 103

APPENDIX A12. Average temperature of corn oil heated in CPET tray for
two minutes. 105

APPENDIX A13. Average temperature of corn oil heated' in CPET tray for
two minutes. 107

APPENDIX A14. Average temperature of corn oil heated in CPET tray for
two minutes. 110

APPENDIX B. Temperature recorded by the four probes at four interface
locations in the susceptor material after one minute of exposure. ...........«. .. 113

APPENDIX C. Sample calculation of concentration of BHET, DMT, DET,
and Cyclic Trimer from corn oil extracts. 114

 

LIST OF TABLES
Table 1. Federal regulations on food packages and components - - - 18
Table 2. Highest temperature attained by corn oil in susceptor material and
CPET trayfor l to 7 minutes ................................................................................... 40
Table 3. Area response of DMT, DET, and BHET standards at different
concenu'ations ......................................................................................................... 51
Table 4. Percent recovery of DMT and DET from corn oil ................................... 54
Table 5. Calibration factors of DMT, DET, BHET, and Cych Trimer standards
................................................................................................................................. 61
Table 6. Average area response of DMT, DET, and BHET from corn all
samples ................................................................................................................... 62
Table 7. Concentration of DMT, DET, and BIIET extracted from susceptor
material for 1 to 7 minutes exposure ...................................................................... 62

Table 8. Comparison of experimental conditions and concentrations of
compounds with the James River studies ............................................................... 64

TABLES OF FIGURES

Figure 1. Sales of microwave ovens and microwaveable foods 1n the United

 

 

States ...... _ - -- - - - -- - - ....... 2
Figure 2. The electromagnetic spectrum. ............ - _ -- 6
Figure 3. A plane monochromatic elecuomagnetic wave ..................................... 8
Figure 4. Susceptor material ................................................................................... 12
Figure 5. Selective heating in a microwavable multi-component container ......... 14
Figure 6. Time-temperature differentials between three microwaveable

containers ................................................................................................................ 15
Figure 7. Schematic of diffusion mechanisms ....................................................... 19
Figlne 8. Experimental design ............................................................................... 27
Figure 9. Migration cell for susceptor material ..................................................... 29
Figure 10. Preset locations in the plastic probe guide where interface

temperatures were recorded for all runs ................................................................. 32
Figure 11. Set-up of experimental apparatus ......................................................... 33
Figure 12. Infra-red spectrum of polyethylene terepthalate ................................. 37
Figure 13. Infra-red spectrum of the food contact layer of susceptor material ...... 38
Figure 14. Infra-red spectrum of the food contact layer of the CPET tray ............ 39

Figure 15. Oil temperature profiles at four interface locations in a susceptor after
1 minute of exposure .............................................................................................. 42

Figure 16. Temperature profiles of corn oil at the interface of the susceptor
material for 2 to 7 minutes exposure - ...... . ............................................ 44

Figure 17. Temperature profiles of corn oil at the interface of the CPET tray for
2 to 7 minutes exposlne - ............................. 45

 

Figme 18. Temperature profiles of corn oil microwaved for 1 minute in a
susceptor material and in a CPET tray ................................................................... 46

Figure 19. Temperature profiles of corn oil microwaved for 7 minutes in a
susceptor material and in a CPET tray ................................................................... 47

Figure 20. Photograph showing the gradual browning of the susceptor material .. 49

 

Figure 21. Standard curves for BHET, DMT, DET, and Cyclic Trimer ............... 52
Figure 22. Sample chromatogram of DMT, DET, BHET, and Cyclic Trimer
standards at 50 ppm 53
Figure 23. Chromatogram of corn oil extract after 7 minutes exposurein the
susceptor material ................................................................................................... 55
Figure 24. Chromatogram of corn oil extract after 7 minutes expsure in th CPET 6
tray ........................................................................................................................... 5
Figure 25. Chromatogram of corn oil blank for the susceptor material after 7
minutes of exposure ................................................................................................ 57
Figure 26. Chromatogram of corn oil blank before microwave exposure .............. 58

Figure 27. Concentration of DMT, DET, BHET, and Cyclic Trimer extracted
from corn oil samples heated in the susceptor material for 1 to 7 minutes ............ 64

CHAPTER 1

INTRODUCTION AND OBJECTIVES

Making products that are microwaveable is an important current thrust of the food
industry. This is spared by demands for consumer convenience and changes in
demographics and lifestyles. For example, there are more women in the work force, a
smaller number of people per family, dual-income families, and single parent homes. All
of these factors have caused the sales of microwave ovens and microwaveable foods to
rise dramatically.

Since its introduction in 1967, the microwave oven has experienced exponential
growth. In 1986, 40% of US. homes (Rosean and Higgins, 1987) and 20% of
British homes (Guise, 1986) owned a microwave oven. And in the 1990’s, it is estimated
that the saturation of microwaves in United States homes will be close to 90% (Anon,
1988). Figure 1 shows the number of microwave ovens shipped and the share of
microwaveable foods in the food market in the United States (Huang, 1987). The number
of microwave ovens shipped increased by a factor of 10 from 1 million units in 1978 to
about 10 million units in 1988. Sales of microwaveable packaged foods were in the
' vicinity of $4.5 billion in 1986, up from about $500 million in 1930, representing an
increase of 800% over the five year period.

According to Productscan Database (Marketing Intelligence Service), over 8% of
the roughly 2,500 new food products introduced in 1986 were targeted as microwaveable.
This is about double the number in 1985 (Rathenberger, 1987). This figure would

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probably be increased further since foods which were formerly packaged for
conventional preparation are now appearing in containers for use in both conventional
and microwave ovens (Anon, 1987). Among the foods that 'will experience growth in the
microwaveable packaged foods market, microwave packaged frozen foods are expected
to have a 14% growth rate, and shelf stable foods were expected to grow at an explosive
rate of 73% (Rosenkranz and Higgins, 1987).

In spite of the growing use of microwave ovens and microwaveable foods,
development of cookware for microwave ovens is lagging. This is primarily due to the
limited number of materials that can be safely used in a microwave oven. Most of the
packages used in the market use either polyethylene terephthalate (PET) or crystallized
polyethylene terephthalate (CPET). These materials are heat tolerant and have excellent
mechanical properties. PET in its amorphous state has a heat resistance range lower than
its glass transition temperature, which is about 98°C. In the crystallized form, it is more
heat stable and can tolerate temperatures of up to 177-205°C (Wright, 1984).

Due to the lack of microwaveable utensils, home-owners and microwave users
have been using household items such as aluminum foil, metal pans, plastic cups, bowls,
trays and plastic wraps in the microwave oven. Aluminum foil and metal pans are ideal
for conventional ovens, but are not recommended for microwave ovens for use with
foods because improper use can cause arcing in the microwave oven. And, using
household plastic in the microwave oven may expose the material to thermal conditions
beyond what they were originally approved for use by the Food and Drug Administration
(FDA) (Bishop and Dye, 1982).

Most household plastics are not suitable because of the high temperatrues attained

in microwave ovens. It was previously believed that temperatures of foods heated in

microwave ovens did not exceed 100°C. However, there have been instances where
consumers have reported popcorn bags catching fire dluing heating in microwave ovens
(McCowin and Brown, 1988). This indicates that the temperature had exceeded 232°C,
the temperature at which paper or wood fibers ignite. Recent evidence has indicated that
localized package temperatures may be in excess of 260°C in microwave ovens,
especially with the new susceptor packages that are used for browning and crisping
(Borodinsky, 1988).

With the increasing use of these materials, the FDA has expressed concerns about
food-package interactions, especially with respect to the migration of packaging
components into foods. Even though these plastics will not melt, it has been known that
additives in the plastics migrate at high temperatures into the food material (Bishop and
Dye, 1982).

The purpose of this study was to determine if there was any migration of
substances from the material to the food during elevated heating (ZOO-260°C) in a

microwave oven and to identify and quantify these migrants. The specific objectives are:

1. To determine the effect of temperature on the migration of components of packaging
materials into foods; in particular, to correlate the temperature at the interface of the
product and the container to the level of migration observed

2. To do a comparative study of migration levels of four major migrant components

fiom two packaging systems.

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

The design of food products and packages for use in a microwave oven presents a
challenge to food and packaging scientists. To develop high quality products and
packages, one must first understand the heating behavior of foods in the microwave oven,
and how packaging materials influence and are influenced by the microwave fields.

Some of the areas that need special attention are the development of packaging
systems that can provide evenness of heating and reconstitution temperatures in foods to
provide microbiologically safe preparation, design of safety features for handling
packages that are to be opened while hot, and release of indirect food additives from the
packaging materials at elevated temperatures (Perry, 1987a).

2.2 Microwave Heating
2.2.1 Microwave radiation

Microwave is a form of electromagnetic radiation; that is, its mode of heating is via
a radiant process. It is located between the radio and infra-red regions in the
electromagnetic spectrum, and has a frequency of 10’Hertz (Hz) as shown in Figure 2

Frequency (H002)

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(Source: Dixon et al., 1988)

(Dixon et al., 1988). Almost all household microwave ovens operate at one of two

frequencies: 915 MHz and 2450 MHz. In air, this corresponds to a wavelength of about
12.24 cm.

The wavelength is related to the frequency by:

)3
ll
<1“

(1)

where c is the speed of light (3 x 10lo cm/s), v is the frequency (Hz) and A is the
wavelength (cm).

Microwave radiation has an electric (E) and a magnetic (H) component (Figure 3).
The electric and magnetic components oscillate in the form of sine waves perpendicular
to each other at 2.45 x 109 cycles per second (2450 MHz) and 9.15 x 10' cycles per
second (915 MHz), respectively. In a microwave oven, the electric component interacts
with the positive and negative charge regions of materials with molecular dipoles (eg.
water) causing them to rotate at the same frequency so as to realign themselves to the
rapidly changing electric field. The motion created by these molecules disrupts the
hydrogen bonds between neighboring molecules, causing the food to be heated by
fiictional energy (Mudgett, 1989).

Positive and negative mobile ions or electrons (eg. salts, oils and fats) are also
affected by the electric component of the field. The mobile ions migrate towards
apposiwa charged regions of the elecuic field, again disrupting the hydrogen bonds and
generating heat (Mudgett, 1989). Oils and fats have components that couple with the

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electric component of the microwave that causes it to heat upon exposure.

2.2.2 Dielectric Constants and the Loss Tangent .

The heating of foods in a microwave oven depends on the dielectric properties of
the foods. The two important constants that define the dielectric properties of materials
are the relative dielectric constant (relative to free space) and the loss factor. The
dielectric constant, K’, is the measure of a material’s ability to store electrical energy.
The loss factor, K", is a measure of how effectively the food dissipates microwave energy
throughout the material. The greater the dielectric constant of the food material, the
slower the velocity of the microwave through the food. This effect is more pronounced at
the interface of the food material and air. If the dielecuic constant of the food is very
large compared to air (dielectric constant of air is 0), the microwave will be reflected off
the surface of the food. This is the reason why most foods do not generally brown or get
crisp in the microwave oven (Keefer, 1986).

The ratio of the dielectric loss to the dielectric constant is defined as the loss

tangent:

tan5=5.- (2)
K

The loss tangent is related to the material’s susceptibility to penetration by
microwave radiation, and its ability to dissipate electrical energy as heat (Mudgett, 1986).
The dielecuic properties of food and other biological materials at microwave frequencies

may be determined by their moisture, solid and salt content (Swami and Mudgett, 1981).

10

2.3 Types of Microwave Packages

Packages for microwave ovens can be grouped into four categories: a) transparent,
b) absorbing, c) shielding, and d) field modifying. Each of these categories is described
in detail below.

2.3.1 Transparent Materials

Like the name implies, these packages are u'ansparent to electromagnetic waves.
The waves penetrate the material to the food where they are absorbed, resulting in direct
heating of the products. These type of packages are suitable for liquid foods such as
sauces, vegetables, soups, etc. Heating is more uniform in these types of packages if they
are closed, because the named water vapor can enhance the heating of the product. As
long as water is present and atmospheric pressure is maintained, the temperature in the

container will be 100°C at the maximum. Some of the polymers used in this category are
polyethylene, polypropylene, polyester, nylon and paper products (Perry, 1987b).

2.3.2 Absorbing Materials

These materials are used to brown and crisp food by coupling with the electric
component of the microwave radiation. Collectively, these materials are called
"susceptors." Turpin (1980), the inventor of susceptor material technology, defined it as
a material that absorbs microwave energy by coupling with the electric field component
of the microwave radiation and through resistive heating in the thin metal film,
microwave energy is converted into sensible heat. This sensible heat warms the product
surface in contact with it by conventional thermal conduction, thereby promoting
browning and crisping in the food product.

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Basically, the material consists of a thin layer of metal vacuum deposited on a
heat-set plastic carrier film (Figlne 4). In most common types, aluminum is deposited on
a 48 gauge oriented polyethylene terephthalate (PET) film which is then laminated with
adhesive onto a paperboard for structural rigidity. Apart from providing a heat resistant
substrate for metallization, the polyester layer is also suitable for food contact. During
heating of the food. the metallized surface is away from the food for two reasons: 1) to
protect the aluminum fi'om chemical or physical damage fi'om food components, and 2)
to prevent the aluminum from becoming an indirect food additive (Perry, 1987b).

2.3.3 Shielding Materials

Shields are metallic structures that are thick enough that they reflect microwave
energy, without getting heated. Shielding materials can be used in a microwave oven to
prevent electromagnetic waves fi'om reaching a product or parts of a product. For
example, in a multi-section one meal tray, which contains a main course and a dessert in
the same tray one would want the main course (eg. meat) to be hot and the dessert to
remain cool. By using the shielding material, the electromagnetic fields can be directed
away from the dessert section to the main course section.

A shield can be aluminium foil, foil laminated to a substrate, or any metal sheets
such as aluminium pans and trays. Even though these materials can be used in the
microwave oven, their use requires special precautions to avoid arcing. Arcing results
when a wave is reflected off the edge or comer of a metallic surface, and can cause

damage to the magnetron if the waves are reflected towards it. Shields can also cause a

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large electrical potential build-up on the shielding material. If this area comes into
contact with a grounded sluface or anorher shielding material at a different potential, this
can cause an electric spark in the oven.

Arcing can be conuolled by several methods: by coating the foil with a non
conducting elecuical insulator, heating metal pans inside their paperboard carton, or
designing packages that give a uniform electric component to prevent build up of electric
potential (Perry, 1987a).

2.3.4 Field Intensifying Materials

These packages focus and intensify the microwave field in a manner similar to a
lens; they focus microwave energy in the same way a lens focuses light (Rosenkranz and
Higgins, 1987). This packaging system allows modification of the electromagnetic fields
to provide a) uniform heating, b) selective heating, c) browning and crisping, and d)
arcing prevention. This technique is best represented by the "micro-match" package of
Alcan Canada Product, Ltd. (Keefer, 1986). Their system utilizes a high technology lid
structure and an aluminium base. The lid contains active components, which are used to
generate intense fields at the surface of a food material that requires browning and
crisping. For selective heating. these active components balance the heating distribution
of a multi-component meal tray (Figure 5).

Figure 6 shows the comparison of the temperatlne differentials of a "micro-match"
container with a transparent and an aluminium container. The temperature differentials
across the food heated in the field intensifying container is much more even than in the
others. For more uniform heating, the active component in the oven acts as a

mode-stirrer, and allows better distribution of heating across the container (Keefer, 1986).

14

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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16

2.4 Migration of Packaging Components
2.4.1 Introduction

Migration is the generic term given to the transfer of a substance from the polymeric
mauix to the food. The substances include monomers and low molecular weight
residues, processing aids (lubricants, antislip agents and antistatic agents), plasticizers,
adhesives, and additives (antioxidant, colorants, etc.; Bishop and Dye, 1982). The
following may produce off-flavors in the food as well as additives that may represent a
toxic hazard to consumers: vinyl chloride (Bartsch et al., 1976), acetonitrlle (Di Pasquale,
1978; McNeal et a1, 1979; Gilbert and Starrin, 1982) and esters of phthalic acid
(Lawrence et al., 1975).

2.4.2 Global and Specific Migration

There are two types of migration: glam and mm. Global migration refers to
the total transfer or migration of all species from the package to the food. It relates to the
transfer of all substances to the food whether they are toxic or not. Specific migration
relates to one or more identifiable substances (eg. a particular monomer) that are
constituents of the packaging material (Giacin, 1980).

Total or global migration can be measured byiweight differences. This consists of
placing a sample of a material of known surface area in contact with an appropriate food
simulant or solvent under defined time-temperature conditions (Anon, 1976) and
determining total u'ansfer by weight difi'crence.

The limits of specific migration are defined by those compounds known or deemed
potentially hazardous to human health; no account is taken of the total quantity of other

17

migrants transferring into the contact phase. Determination and quantification of specific
migration varies with the type of nrigrant of interest. Several methods are discussed in
detail in Giacin and Brzozowska (1985) and Crompton (1979).

2.4.3 Direct and Indirect Additives

Migration can either be direct or indirect. Direct additives are substances added
directly to the food or packaging materials. Examples include antioxidants added to
cooking oil and cereal boxes to prevent oxidation or rancidity. Indirect additives are
those substances that are found to migrate from the package to the food. Both direct and
indirect additives are regulated equally by the same statutes, the 1958 Food Additives
Amendment of the Federal Food, Drug and Cosmetic Act of 1938. Federal regulations
which apply to food package components are listed in Table 1 (Risch, 1988).

2.4.4 Theoretical Considerations
2.4.4.1 Mass Transfer in Polymeric Films

The movement or transfer of a migrant through a polymeric film can be described
by three generalized mass transfer models which are represented schematically in Figure
7 (Gilbert et al., 1980).

The migration of a component from a package mass to the food is basically a
desorption process which depends on the diffusivity of the migrating species. Diffusivity
is defined as the tendency of a substance to permeate through the polymer bulk phase.
The diffusion process is described by Fick’s first law:

18

Table 1. Federal regulations on food packages and package components.

 

 

 

 

Code of Federal Topic
Regulation Citation

21 CFR Part 170 Food additives

21 CFR Part 172 General information an indirect food
additives

21 CFR Part 175 Indirect food additives: adhesives,
coatings and components of coatings

21 CFR Part 176 Indirect food additives: paper and
paper components

21 CFR Part 177 Indirect food additives: polymers

21 CFR Part 178 Indirect food additives: adjuvants,
production aids and sanitizers

21 CFR Part 179 Irradiation in production, processing
and handling of food

21 CFR Part 181 Prior-sanctioned food ingredients

21 CFR Part 182 Substances GRAS'

21 CFR Part 186 Indirect food substances, GRAS

 

(Source: Risch, 1988)
‘Generally Recognized As Safe

 

19

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20

But 3c
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where c is the migrant concenu'ation in the polymer, D is the diffusion coefi'icient of the
species in the polymer, m is the mass of the component transferred, t is the time taken for
the species to diffuse, A is the area of the plane across which diffusion takes place, and x
is the path of diffusion (Crosby, 1981).

Fick’s second law describes the diffusion process over an infinite surface area (that
is, diffusion from a sheet):

a 3’

where x is the distance measmed from the polymer-contacting interface into the polymer.
Migration is, therefore, a mass u'ansport process under defined secondary conditions (i.e.
time, temperature, and nature of the contact phase). The driving force for mass transport
processes is the concenu'ation difference or gradient, where dissolved species diffuse
fiom a region of higher concentration to a region of lower concentration.

For desorption to occur, the migrant will have to undergo two processes in
succession: 1) diffusion of the migrant to the polymer surface, and 2) subsequent
desorbtion of the migrant accumulated at the surface to the contact phase.

In addition, the desorption of a migrant through a polymer to a contacting phase
can be considered a function of the polymer-migrant interaction affinity and diffusion.
The affinity of the polymer-migrant interaction will determine the equilibrium amount of
migrant transferred to a contacting phase (Giacin, 1980). Thus affinity becomes

21

increasingly important as the migrant concenu'ation decreases because diffusion of the
migrant through the polymer will affect the rate at which equilibrium is attained (Gilbert.
1976).

Briston and Katan (1974) described three packaging material contact phase systems
in terms of migrant diffusivity: 1) non-migrating 2) independently migrating, and 3)
leaching. In system 1, transfer of the components occurs only from the packaging
surface. The diffusion coefficient approaches zero, and cannot be measured. In system
2, the diffusion coefficient can be measured under the time-temperature conditions of the
study. This system normally applies to volatile components such as monomers and. in
some cases, plasticizers and antioxidants. In this system, the rate and amount of migrant
transferred depends on the contact phase volume and boundary layer resistance in the
extracting phases at the time of desorption, especially for components that tend to
partition strongly toward the polymer phase (Giacin, 1980). In system 3, components of
the contacting phases, such as solvents, penetrate into the polymer and cause swelling
and disorientation of the polymer su'ucture. This plasticizing effect enhances the

diffusivity of the migrant. resulting in an increased rate of migration.

2.4.5 Review of Migration Studies

Much work has been done on the migration of additives from packaging materials
into foods. Giam and Wong (1987) has compiled an extensive list of studies done on the
migration of different plasticizers into foods and pharmaceutical products. Others who
have also researched the migration of plasticizers fi'om food packages into foods include
Startin et a1. (1987), Castle et a1. (1987, 1988a, 1988b), and Bishop and Dye (1982).
Miltz and Rosen-Doody (1984), Adcock et a1. (1984), Withey and Collin (1978), and

Varner et al. (1983) have done studies on the migration of monomers and low molecular
weight residues. Bieber et a1. (1985) and Schowpe et a1. (1987) conducted studies on
migration of antioxidants, and Hotchkiss and Landois-Garza (1987), studied migration of
aroma and flavor compounds fiom packaging materials.

To conduct a migration study, an extensive range of variables have to be
considered. Many times, results from one group of researchers are difficult to relate to
another group because of differences in choice of temperature and heating times. For this
reason, the regulating bodies have recommended the time and temperature for use in
migration studies.

One condition for accelerated migration studies is that the extraction tests should
be run to equilibrium at a minimum temperature of 49°C for 10 days in a recommended
extraction test cell using food simulating liquids in place of real foods (Anon, 1976): for
example, water for aqueous food. 3% aqueous acetic acid for acidic food, 8% to 50%
aqueous ethanol for alcoholic foods, and heptane for fatty foods.

There are, however, no regulations for adhesives, paper or plastics used in
microwave ovens because when the laws were passed for these materials, they were used
at temperatures not exceeding room temperature, and the regulatory agencies did not find
it necessary to set an upper temperature limit. Now, with susceptor materials where
temperatures can exceed 232°C, regulatory agencies are concerned about the thermal
integrity of the package. Mitchell (1988) reported that studies conducted so far have
indicated that there is evidence of cracking and melting of PET film and browning of the
paperboard.

Many studies on migration of components from food packaging materials have
been reported in the literature, as evidenced by some of the examples given in the

23

previous section. However, not much has been done in investigating the migration of
packaging materials in microwaveable cookware. The few studies done so far have
shown that migration does occur (Bishop and Dye, 1982; Startin et al., 1987; Dixon et al.,
1988; and Heath and Reilly, 1981). With respect to susceptor materials, migration
studies are in the process of being carried out by a few groups of researchers, including
the FDA. The following is a discussion of some of the migration studies that have been
conducted

Studies on the migration of the plasticizer di-(2-ethylhexyl) adipate (DEHA) from
packaging films in the microwave have been reported by Bishop and Dye (1982), and
Startin et al. (1987). Bishop and Dye (1982) studied the migration of the plasticizer from
a plastic wrap material after 10 minutes of exposure in the microwave oven. They used a
vegetable oil to trap the escaped plasticizer and the oil was analyzed by gas
chromatography. The average concentration of DEHA migrated from the plastic wrap
was 33.35 mg/dm’, equivalent to 23% of the weight of the plastic wrap used. The
minimum quantity detected was 1 ng/dm’. When they compared these results to samples
of the same plastic wrap exposed to. vegetable oil for 10 minutes at 20°C, no DEHA peak
was produced fiom the oil sample.

Startin et a1. (1987) studied the migration of DEHA from a flexible packaging film
into a variety of foods during in-home use of PVC films for such purposes as covering
the food during microwave reheating of cooked food. They found that migration of the
compound did occur, and increased with increased contact time and temperature. It was
also reported that the level of migration was highest where there was direct contact
between the film and food with a high fat content at the surface. DEHA levels were

highest for microwave cooked meats (151 mg/kg for roast chicken and 351 mg/kg for
park spare ribs) and lowest for microwave cooked vegetables (3 mg/kg for carrots and 4
mg/kg for potatoes).

Heath and Reilly (1981) investigated the possibility of migration of the plasticizer
acetyl-tributyl citrate (ATBC) fiom a plastic film into poultry meat and model food
systems in a microwave oven, and reported significant migration. They reported that the
amount of ATBC found in the poultry meat increased as the residence time in the
microwave increased. The quantities migrated reached a plateau after about 8 minutes of
cooking. In the model food system, they found that the lipid portion of the system
contained most of the migrants and was responsible for the retention of acetyl
tributyl-citrate in the sample. An increase in the lipid portion of the food system also
increased the amount of ATBC found. They also found that the amount of food in
contact with the film during cooking was an important factor which influenced the
amount of ATBC transferred from the film.

Dixon et al. (1988) conducted another migration study using a thermoformed,
microwaveable container made fiom polypropylene/Saran/polypropylene co-extruded
material. Five components (2,5-dimethyl nonane, 2-methyl undecane, butylated
hydroxytoluene (BHT), 5-ethyl-5-methyl decane, and lSC-hydrocarbon) were detected
and quantified using a headspace gas chromatography procedure. They observed that the
quantities increased with increased microwave exposure.

A small number of studies on the migration of components fiom susceptor
materials have been reported. Preliminary test results conducted by the FDA on the
effect of temperature on susceptor material in microwave ovens showed that susceptors

can reach temperatures above 260°C during microwave heating Mitchell, (1988). Using a

25

dye test, it was observed that at this temperature, the film surface intended to be a barrier
layer for food contact had cracks, and in some places the polyester film had already
melted (Mitchell, 1988). The crack actually penetrated through to the paper and adhesive
level below the food contact surface.

In anather study, Lentz and Crosset (1988) of the Pillsbury Company conducted a
test to determine the temperature at the interface of several foods (popcorn, pizza, fish
fillets) in susceptor materials during microwave heating. In one of their tests,
temperatures as high as 276°C and 265°C were recorded after 4 minutes at several places
in a popcorn bag using Luxuon probes. The maximum temperature observed during
trials using fish fillet was 222°C. It can be seen that temperatures reached in these studies
exceeded 205°C.

Schroeder (1989) carried out a migration study on migration in susceptors using
the method proposed by the FDA for identifying non-volatile migrating species from
microwaveable containers laminated with a food contact liner of polyethylene
terephthalate. Using a 700 W oven, the susceptor material was exposed for 5 minutes to
microwave radiation at full power. The highest temperature recorded was 250°C,
suggesting that that location was a hot spot in the microwave oven. The average
temperature across the susceptor material was about 232°C. The major compound
present as a result of the degradation of the PET layer was cyclic trimer, with a
concentration of 12330 mg/dm’. Other compounds found were BI-IET (38.64 mg/dm’),
DET (334.0 mg/dm’), and several oligomers of PET: tetramer, pentamer, hexamer,
heptamer, octamer, and nonamer. The concentration of the oligomers obtained at the

same exposure time were 0.29, 0.22, 0.16, 0.09, and 0.02 mg/dm’, respectively.

26

CHAPTER 3

MATERIALS AND METHOD

3.1 Introduction
The analysis used in this study follows the method proposed by the FDA

(Schroeder, 1989) for non-volatile extractables in corn oil heated in microwave
containers that are laminated with a food contact liner of polyethylene terephthalate
(PET) polyester. This method is also being considered for adoption as a standard method
by the American Society for Testing and Materials (AST'M) (Schroeder, 1989).

3.2 Experimental Design

Figure 8 shows the experimental design used in this study. Two packaging systems
were used: a susceptor material and crystalized polyethylene terephthalate (CPET).
Temperatures at the interface of the food simulant, and test material were monitored with
a four-probe Luxuon fluoroptic system (Luxtron Corp., Mountain View, CA) over
residence times ranging from 1 to 7 minutes. Corn oil was used as the food simulant and
glass beads were used to simulate inert food particles.

Three runs were carried out at each exposure time, using a fresh sample for each
run. The temperatures recorded by the four probes in each run were average to obtain the

overall temperature profile of the sample at the interface of the test material in that run.

27

EXPOSURE TIME

I
Y

CORN OIL SAMPLES
./ l \
i
i \\

SAMPLE A SAMPLE B SAMPLE C

/\/

EXTRACTION EXTRACTION EXTRACTION

HPLC ANALYSIS

Figure 8. EXperimentaI Design

28

The three average temperature profiles were again averaged to give the final temperature
profile of each sample for each exposure time.

ThreeextractionsweredoneoneachcornoiltrialandthreerunsofHPLCdoneon
each extraction. All the area responses obtained from the corn all samples for each
extraction were averaged. and the averaged value was used to calculate the concenuation
of the migrant.

3.3 Samples and Materials
Both test materials were provided by leading manufacturers. The CPET material

came in preformed trays measuring 12 cm x 12 cm x 3 cm. The susceptor material came
in flat sheets, and were cut into discs of 13.5 cm diameter to be used in a specially
designed migration cell (Figure 9). This procedure allows for a constant surface area of
contact and constant simulant volume. The migration cell consists of a Teflon cylinder
and a round Teflon base. Teflon was chosen because it can withstand temperatures of up
to 260°C without adverse efiects on its structure. The cylinder is open at both ends, with
a wall thickness of 2.0 cm and a diameter of 12.0 cm. The base is also 2.0 cm thick with
a diameter of 19.0 cm. One end of the cylinder can be secured to the base by nylon
screws drilled through the wall of the cylinder. A fully assembled cell would have the
packaging material sitting on top of a silicone gasket on the Teflon base, secured to the
upper cylinder on top of the packaging material so that a constant exposme area is
obtained. This also prevents any edge effects, i.e. migration of components from the cut
edge of the packaging material into the food simulant. All the materials used in

conng the migration cell were obtained from McMasters, Inc., Chicago, Ill.

29

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Polyethylene terephthalate cyclic trimer, diethyl terephthalate (DET), dimethyl
terephthalate (DMT), and bis-(2-hydroxyethyl) terephthalate (BI-IET) standards were
used to identify specific migrants. PET cyclic trimer, DET, and DMT were obtained
from the Eastman Kodak Co., Rochester, N .Y.. BHET was obtained from the Research
Laboratories, Tennessee Eastman Company. Dimethylacetamide (DMAC) was obtained
from the Eastman Kodak Co., Rochester, NY. All solvents used were HPLC grade and
were obtained from Aldrich Chemical Co., Milwaukee, Wisconsin.

The corn oil (Mazola 100% Pure Corrl Oil, Best Foods, CPC International, Inc.,
Englewood Cliffs, NJ.) was purchased from a local supermarket and refiigerated before
each use. It was allowed to equilibrate at room temperatrue before it was used in the
experiments. The glass beads were cleaned thoroughly with acetonitrile and dried in air

before use.

3.4 Verification of Materials Used

The food contact surface of the test materials were verified using a Perkin-Elmer
1330 Infrared Spectrophotometer. The attenuated total reflectance (ATR) apparatus was
used instead of the direct transmission method because of the thickness and opaqueness
of the materials. The infiared spectra of the test materials were then compared to the
spectrum of a polyethylene terephthalate polymer run on the same apparatus.

31

3.5 Microwave Exposure

Glass beads (57.2 g) were placed in the fully assembled cell (susceptor material) or
CPET tray so that they formed a single layer on the test material (0.5 g/cm’). 17.2 g of
corn oil was poured into the cell, and 13.5 g into the tray, so as to maintain a ratio of 0.15
g of corn oil to one cm2 of sample surface.

The cell (or tray) was placed in a Litton 500 Watt (2450 MHz) microwave oven
(Litton Systems, Inc., Minneapolis, MN) with a cavity measuring 36 cm x 30 cm x 19
cm. The cell (or tray) was placed at exactly the same location in the oven for every run
so as to maintain consistency across all trials.

The temperature of the corn oil at the interface of the test materials was
simultaneously recorded at four preset locations by Luxuon probes (Luxuon Corp.,
Mountain View, CA) (Figure 10). For the susceptor material, the temperatures were
recorded at intervals of 2 seconds. For the CPET tray, the temperatures were recorded at
4 second intervals. The temperature data were transferred to a computer via a RS 232
serial port. The setup is illustrated in Figure 11. Temperature probes were inserted
through pre-drilled holes at the back of the oven, through a plastic probe guide, and the
guide aligned so that it was in the same position for each run.

The oil was exposed to microwave energy at full power for residence times of l to
7 minutes. A 600 ml glass beaker containing 90 ml of distilled water at room
temperature was placed at the back of the oven before each microwave exposure to
simulate a food load. The oven cavity was then allowed to cool to room temperature

before the next run was made.

32

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To determine corn oil blank properties, the same amount of corn oil and glass
beads were put in a petri dish. Each packaging material was placed under the petri dish

and the dish microwaved as above.

3.6 Extraction Procedure

The hot oil was stirred before taking a 3.00 1; 0.003 g portion for analysis. The oil
was mixed with 25 ml hexane, stirred and transferred to a 250 ml separatory funnel. The
beaker was rinsed with 25 ml of fresh hexane and added to the first hexane-com oil
mixture. The beaker was then rinsed with 25 ml acetonitrile, stirred, and added to the
hexane mixtures. The funnel was shaken and the layers were allowed to separate. The
acetoniuile layer was drawn into a 50 ml conical test-tube and the procedure was
repeated with 25 ml of fresh acetonitrile. The extracts were combined and evaporated to
0.4 to 0.5 ml under a gentle stream of nitrogen gas during heating at 65°C in a
temperature-controlled water bath. The residue was cooled and brought up to 2 ml with

dimethylacetamide (DMAC) prior to analysis by liquid chromatography.

3.7 High Pressure Liquid Chromatography (HPLC) Analysis

Each concentrate was injected into a high performance liquid chromatography
system using gradient elution. The compounds were quantitatively analyzed using a
Perkin-Elmer Model Series 38 liquid chromatography system (Perkin-Elmer, Inc.,
Norwalk, CT) equipped with a 20 pl. loop injection valve, a pump capable of 1.5 ml/min,
and an LC-100 oven. A Rainin Microsorb C-8 (250 mm x 4.6 mm, 5 um size) (Brown

35

Laboratories, Santa Clara, CA) column was used with two mobile phases: mobile phase
A was 85:15:025 waterzacetonitrile:glacial acetic acid and mobile phase B was
15:85 :0.25 waterzacetoniuilezglacial acetic acid.

A linear gradient program was set up to go from 5 to 60% B in 8 minutes, to 70%
Bin9min.,t0100% Bin7minandholdat100% Bfor 16min. ataflowrateofl.0
mllmin. The eluant was detected using a Perkin—Elmer LC-75 UV Specuophotometer set
at 254 nm. A SP 4200 integrator (Spectra-Physics, Inc., San Jose, CA) with chart speed
of 1 in/min was used for the integration of the peaks.

3.8 Preparation of Calibration Curves

An external standard was used to quantitate the major components eluting from the
liquid chromatography system. Standard solutions of 100, 50, 10, and 5 ppm were
prepared by dissolving each standard in DMAC. Each standard was injected into the
liquid chromatography system, under the same conditions used for the analysis of test
samples.

A calibration curve was constructed by plotting the response area of each standard

versus concentration.

36

CHAPTER 4

RESULTS AND DISCUSSIONS

4.1 Material Verification

The infra-red spectrum of polyethylene terephthalate is shown in Figure 12. The
spectra of the food contact surface of the susceptor material and CPET tray are shown in
Figures 13 and 14, respectively. The infra-red spectra of the food contact surface of the
susceptor material and the CPET tray show absorbtion bands identical to those present in
the infra-red spectrum of the polyethylene terephthalate polymer, verifying that the food

contact surface of the two test materials is polyethylene terephthalate.

4.2 Microwave Exposure

4.2.1 Exposure Time versus Temperature

The highest temperatmes attained by the corn oil at the interface of the susceptor
material ranged fiom 136.4°C at 1 minute to 244.8°C at 7 minutes. In the CPET tray, the
highest temperatures attained ranged from 34.1°C to 81.9°C for the same length of
exposure. The highest temperatures attained in both materials at the end of each heating
time are summarized in Table 2.

It was difficult to obtain uniform temperatures during each trial in the range of

exposure times used. Temperatures varied slightly across uials, even though each probe

 

37

 

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Table 2. Highest temperatures attained by the corn oil in the susceptor material and CPET
tray during microwave exposure for l to 7 minutes.

 

 

 

 

 

 

 

 

Exposure Time, 3 Temperature. °C
Susceptor Material CPET Tray
60 136.4(6.1): 34..:1(39)
120 186.0 (3 .:4) 45. 8 (0.7):
180 196.6 (3 .:4) 59.9 (3 .9:)
240 205.4 (1.8): 73.6 (8.0):
300 217. 8 (6. 6): 78 .9 (9. 7):
360 225 .0 (6.3): 75.6 (3 .:O)
420 244. 8 (7 .0) 81 .9 (3 .7)
° Standard deviation

was located at the same spot in the microwave. It is possible that during trials.
convection currents created in the oil at higher temperatures either caused the probes to
move away from their original positions or raised them slightly from the interface of the
oil and test material. This effect is clearly demonstrated in the temperature profile of
corn oil heated in the CPET tray for 6 minutes. The temperature of the corn oil at the
interface of the CPET tray was lower at 6 minutes than at 5 minutes of exposure (75.6°C
versus 789°C) (see Table 2).

. This fluctuation could also be due to several other factors (Berek and Wickersheim,
1988): l) localized heating or localized power absorbtion instead of gradual equilibration
as in a conventional oven; 2) spatial field intensity variations within the oven; 3)
dielectric heating which is influenced by localized moisture content in the food; 4) depth
of penetration of microwave radiation or 5) handling error.

41

As expected. the temperature of the corn oil at the interface of the susceptor
material was much higher than at the interface of the CPET tray. This is a result of
differences in the mode of heating of the two test materials in a microwave oven:
absorbtion of microwave energy by the susceptor material versus transparency of the
CPET to microwave radiation as discussed in Chapter 2. Since the aluminum dr0plets
absorb microwave energy, the oil at the interface of the susceptor material gets heated
more quickly. The CPET tray, being transparent, does not absorb microwave energy,
resulting in lower corn oil temperatures at the interface of the CPET tray. As the CPET
tray itself does not absorb microwave energy, heating depends only on the presence of
microwave absorbers (water, dipolar ions, etc.) in the oil. Since the quantity of these
absorbers in the oil is small, only a modest rise in temperature occurred in the corn oil
heated in the CPET tray.

The temperature data from all experiments are tabulated in Appendix A. Based on
the temperatures recorded by the four probes at specific locations across the exposed
surface area of the test materials, spot or localized heating was prevalent. As exposure
time increased, there was considerable locational variation in temperature between the
probes. To illustrate this, the temperature profiles at four interface locations after 1
minute of heating was plotted against exposure time (Figure 15). Please see Appendix B
for raw data. The initial temperatures measured by probes l, 2, 3, and 4 were 23.9°C,
23.0°C, 235°C, and 23.5 °C. respectively. The average initial temperature was 23.4 °C.
with a standard deviation of .1; 0.2 °C. After 60 minutes, the temperature recorded by the
respective probes were 115.2°C. 135.8°C, 145.6°C, and 148.4°C. The average
temperature was 134.2°C, with a high standard deviation of i 333°C.

42

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Although the variations in temperature between the four probes in each trial were
large, the average temperature of all trials was not significantly different, as shown by the
standard deviations in Table 2. The smallest temperature variation between trials in the
susceptor material was at 4 minutes with a standard deviation of 1.8°C. The largest was
at 7 minutes, with a standard deviation of 7.0°C. The range of temperanrre variation
between the trials in the CPET tray was slightly broader than in the susceptor material.
The smallest variation was at 2 minutes, with a standard deviation of 0.7°C and the
largest was at 5 minutes, with a standard deviation of 9.7°C.

Figures 16 and 17 are plots of the temperature profiles of the corn oil at the
interface of the susceptor material and CPET tray, respectively, after exposure times of 2
through 7 minutes. From these plots, it is clear that in spite of the large temperature
variations encountered at the different locations of the test materials, there is a great deal
of reproducibility in the shape of the average temperature profiles. The profiles from the
susceptor material showed that the temperatures at the interface of the oil and material
tended towards an asymptote with increased exposure time. In addition, the susceptor
material showed better profile reproducibility between exposure times than the CPET
tray. This is indicated by the closeness of the seven temperature profiles.

The rate of temperature increase of the corn oil is three tofour times greater in the
susceptor material than in the CPET tray for the same degree of exposure. For example,
at 1 minute, the temperature of corn oil at the interface of the susceptor material was
136.4°C, while that of the CPET was only 34.1°C; these represent increases of 113°C and
13°C, respectively (Figure 18). After 7 minutes, the temperature of the susceptor material
had reached 244.8°C, while the temperature of the CPET tray had only reached 81.9°C, a
222.0°C change as compared to a 59°C change in temperature (Figure 19). In Figure 19,

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the temperature profile of the susceptor material showed a sharp increase up to about 1
minute of exposure. After 1 minute, the change in temperature is more gradual and the
profile appears to be approaching an asymptote. In contrast, the temperature of corn oil

at the interface of the CPET tray is linear with time, even after 7 minutes of exposure.

4.2.2 Effect of Temperature on Susceptor Material

There were no noticeable changes or breakdown in the structure of the CPET tray
during the range of exposure times used, due primarily to the relatively low temperature
the material was subjected to. However, significant browning of the susceptor material
was observed (Figure 20). A slight browning was observed after 2 minutes of exposure
and increased with increased exposure time. After 6 and 7 minutes of exposure, the
whole surface of the susceptor was browned, and charring was visible on some parts. It
is possible that the position of the parts that were charred coincides with the hot spots in
the microwave oven.

After about four minutes of exposure, oil stains were also noticeable on the
paperboard layer of the susceptor material. This indicates that some form of structural
breakdown (melting, cracking, and/or crazing) of the polyester layer had occurred; no oil
stains were observed for exposure times between 1 and 3 minutes.

This breakdown is probably related to the temperature at the interface of the
susceptor material. The highest temperature attained by the corn oil at the interface of the
susceptor material after 4 minutes was 205.4°C. The heat tolerance range of polyethylene
terephthalate, as discussed in Chapter 1, is between 177 and 205°C. Therefore, after four
minutes of exposure, the temperature of the corn oil at the interface of the susceptor

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50

material had already reached the maximum temperature tolerance of the polyester layer.
Actually, it is likely that the actual temperature at the polyester surface of the susceptor
material is higher than 205.4°C. exceeding the heat tolerance level of the polyester layer.

The breakdown of the polyester layer allowed the oil to seep through, and come
into contact with the paperboard layer below. This accounts for the presence of oil stains
on the paperboard layer. The size of the oil stain on the paperboard layer increased with
exposure time. After 6 and 7 minutes, it was estimated that 90% of the exposed surface
area of the paperboard was covered with oil.

4.3 Analysis of migrants by HPLC.
4.3.1 Standard Curves

The retention time for BI-IET, DMT, DET, and Cyclic Trimer standards were 10.0
(1 0.4), 17.4 (i 0.3), 22.1 (1 0.4), 25.7 (i 0.4) minutes, respectively. Since the method is
a reversed phase chromatography, the more polar compounds with respect to the mobile
phase elute first, followed by the next less polar compound, ending with the least polar
compound. The area response of the standards obtained from the HPLC chromatogram at
each concentration is tabulated in Table 3.

The standard curve was ploned using the area response versus the weight of
standards injected (Figure 21). The correlation coefficients for the standards were all
very good: 1.000 for BI-IET, 0.999 for DMT, 0.999 for DET and 0.997 for Cyclic Trimer.

To identify the unknown peaks from each corn oil sample, the retention time of the
peaks present in the corn oil sample were compared to the retention times of the peaks of
the known standards. Since the conditions of the liquid chromatography used is the same
for both standards and samples, it is assumed that if the compound of interest (BI-IET,

51

Table 3. Area response of Bl-IET, DMT, DET, and Cyclic Trimer standards at different
concentrations.

 

 

 

 

 

 

 

 

 

 

Standard, Area Response, (ARUY
a (1:10”)
DMT DET BHET Cyclic
Trimer
5 10790 9200 9370 9530
10 15360 12630 14400 10670
50 73840 53890 67960 43770
100 143000 108800 135400 87500
'Average value of tluee trials

DET, DMT, Cyclic Trimer) is present in the corn oil sample, it will have the same
retention time. A sample chromatogram of the standards at 50 ppm is shown in Figure
22.

4.3.2 Percent Recovery of Standards.

To determine the percent recovery, corn oil was spiked with known amounts of
DMT and DET standards. The corn oil was then extracted and injected into the HPLC
following the same procedure used to obtain the standard curves for oil samples heated in
the susceptor material and CPET tray. The percent recoveries of the two standards are
listed in Table 4.

The percent recoveries for both DET and DMT were very good. They averaged
96.9% and 96.6%, respectively. The percent recovery of the three trials yielded values

52

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standards at 50 ppm.

54

Table 4. Recovery of DMT and DET from corn oil.

 

 

 

Compound Added, Recovered, % Reoo
118/8 We very.
DET 44.6 43.6 97.7
44.6 43.5 97.6
44.6 42.6 95.5
DMT 42.4 42.0 99.4
42.4 42.1 99.1
42.4 38.7 91.3

 

 

 

 

 

that were very close, with a standard deviation of i 1.2 and :1: 4.6 for DET and DMT,
respectively. Based on the percent recovery of the two standards, it is reasonable to
assume that the compounds of interest present in the corn oil samples would have the

same degree of recovery.

4.3.3 Sample Analysis

A sample chromatogram of the susceptor material and CPET tray after 7 minutes
of exposure are shown in Figures 23 and 24, respectively. Chromatograms for the
susceptor material generally had more peaks than chromatograms for the CPET trays.
However, when compared to the corn oil blank microwaved at the same exposure time,
many of the peaks were found to be identical (Figure 25). Most of the peaks detected in
the corn oil blank appear to be breakdown compounds of the corn oil, because a
chromatogram of an unmicrowaved corn oil showed no significant peaks (Figure 26).
The breakdown is probably thermally induced. The chromatograms of the corn oil

55

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59

extract from the susceptor material also showed several large peaks after 29.0 minutes of
retention time that were absent in the corn oil blank. These peaks do not coincide with
any of the standards used in this study. Therefore, it is possible that the peaks could have
come either from the adhesive or the paperboard layer of the susceptor.

To separate the peaks of compounds migrated from the test materials from the
breakdown compounds, the peaks of each corn oil blank exposed for the same duration as
the sample were subtracted from the chromatograms of the samples. The retention time
of the remaining peaks were then compared to the retention time of the known standards
to identify peaks with the same retention times as the standards.

All four compounds were present in the chromatograms. DMT and DET are
considered residual monomers, BHET is a transesterification product resulting from the
processing of polyethylene terephthalate polymer. Cyclic Trimer is inherent in the
formation of PET by melt polycondensation, and usually add up to about 1-3% by weight
(Kim and Gilbert, 1988). Therefore, it is a natural constituent of all melt-extruded
samples of PET.

The BHET peak was easily located. The corn oil blank did not show any
compounds with a retention time of between 7.5 minutes and 12.63 minutes. The
chromatogram of the corn oil samples showed two compounds that have a retention time
close to BHET. One was at about 9.2 minutes and the other at about 9.9 minutes. When
compared to the retention time of the BHET standard, the retention time of the second
compound was found to be the closest. Thus, that compound was assumed to be BHET.

Peaks for DMT and DET were much harder to detect because of interfering peaks
from compounds that were eluting at the same time. Unfortunately, these compounds

were also UV absorbers in the 254 nm region of the UV spectrum. As a result, a number

of the peaks were detected by the UV detector. The method of identifying the two peaks
involved a process of superimposing the chromatograms obtained from the control and
sample and disregarding common peaks: any peaks present in both the corn oil sample
and the blank were assumed to be the same compound and eliminated. The retention
time of the remaining peaks in the corn oil sample were then compared to the retention
times of the DMT and DET standards. The retention times of the DMT and DET peaks
in the corn oil sample were 17.3 minutes and 22.1 minutes, respectively.

Among the four compounds, the peak for the Cyclic Trimer was the easiest to
identify. While the chromatogram of the corn oil blank has two very prominent peaks;
one at 19.5 and the other 23.3 minutes, the chromatogram of the corn oil sample has four:
at 16.3, 19.5, 23.3, and 25.9 minutes, respectively. From this information, it can be
deduced that the peak at retention times 19.5 and 23.3 minutes are breakdown
compounds of the corn oil. Between the two remaining peaks, the peak with the retention
time of 25 .9 minutes agrees closely with the retention time of the Cyclic Trimer standard,

which is 25.7 minutes.

4.3.4 Concentration of DMT, DET, BHET and Cyclic Trimer

The concentration of DMT, DET, BHET and Cych Trimer in the corn oil samples
were calculated by:

C . Idm’ CF 1: R, 1: VM
oncentranon (pg ) - VW x A (5)

 

61

where CF = calibration factor (the reciprocal of the slope from the standard curve) [grams
per area response units (ARU)] (Table 5); Rs is the area response obtained from the area
of the peak in the chromatogram (ARU) (Table 6); V.“ is the total volume of the sample
(ml); Vb, is the volume of the sample injected into the liquid chromatograph (m1); and A
is the surface area of the test material in contact with the all sample (dm’). A sample

calculation of the concentration of the compounds is given in Appendix C.

Table 5. Calibration factors for DMT, DET, BHET, and Cych Trimer standards.

 

 

C°mP°“nd Slave of Standard curve. Calibration factor (l/Slope),
ARU/g g/ARU
DMT 1.44 x 1010 6.94 x 10'11
DET 1.09 x 1010 9.17 x 10'u
BHET 1.36 x 10‘° 7.35 x 10'H
Cl'clic Trimer 8.81 x 109 1.14 x 1040

 

 

 

 

 

Table 7 summarizes the concentrations of DMT, DET, BHET, and Cyclic Trimer
extracted from the susceptor material at the respective exposure times. The concentration
of the compounds increased with increased temperature of corn oil at the interface of the
test material. The highest concentration of DMT, DET, BHET, and Cych Trimer
extracted were 361.5 ug/dm’. 343.6 ttg/dm’, 42.0 ug/dmz, and 12330 ug/dmz,
respectively. Figure 27 shows the concentration profiles of the four compounds. The
concentration of Cyclic Trimer extracted during the range of exposure times was two
orders of magnitude larger than DMT and DET and about three orders of magnitude
larger than BHET.

Table 6. Average area response of DMT, DET, BHET, and Cyclic Trimer from corn oil

 

 

 

 

 

 

 

 

 

samples
Exposure Time, 8 Area Response, ARU'
DMT DET BHET Cyclic Trimer

60 2360 1470 1080 54400
120 17900 12200 2690 561500
180 27500 12400 2560 565700
240 27400 15600 3340 621200
300 24100 21300 3000 632400
360 25400 21700 3040 616000
420 30400 21900 3200 628400

'Average of three trials

Table 7. Concentration of DMT, DET, BHET, and Cyclic Trimer extracted from

susceptor material after exposure times of 1 to 7 minutes.

 

 

 

 

 

 

 

 

 

Exposure Time, s Concentration, ug/dm”
DMT DET BHET Cyclic Trimer
60 28.1 23.2 13.6 1060
120 212.7 191.7 33.9 10950
180 326.6 194.9 32.2 1 1030
240 325.7 244.8 42.0 12120
300 286.3 334.0 37.7 12330
360 301.1 340.6 38.2 12020
420 361.5 343.6 40.2 12260
°Average of three uials

The profiles also show that the maximum concentration of each compound was

reached within 7 minutes of exposure. BHET does not show significant changes in

concentration with respect to exposure time. However, the concentrations of DMT, DET,

and Cych Trimer changed significantly between 1 and 2 minutes of exposure. The

 

 

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concentration of DMT and DET increased by a factor of 8, from 28.1 ugldm2 to 212.7
uydm’) and from 23.2 tlg/dmz to 191.7 ug/dm’), respectively. The Cych Trimer
experienced a ten-fold increase, from 1060 tig/dm2 to 10950 ug/dmz). DET and DMT
reached a maximum concentration after 5 and 3 minutes, respectively, while Cych
Trimer leveled off after only 1 minute of exposure.

The concentrations found in this study were compared to a preliminary work
reported by Schroeder (1989), the concentration levels of the migrated compounds in the

corn oil were quite different (Table 8).

Table 8. Comparison of experimental conditions and concentrations of BHET, DET, and
Cych Trimer after 5 minutes of exposure.

 

 

 

Schroeder (1989) | This study
Compounds: Concentration, ug/dm’
BHET 3.1 38.6
DET 2914.01 334
Cyclic Trimer 1780 12300
Experimental
conditions:
Oil temperature 232.0°C 217.8°C
Power level 700 W 500 W

 

 

 

 

 

65

BHET migration was ten times higher while the concentration of Cyclic Trimer
was about seven times as much. However, the concentration of DET obtained in this
study was about five times smaller than their reported value. These differences can be
attributed to a variation in experimental temperature, the type of oven used, and the fact
that different susceptor boards were used in the two studies. No comparison could be
made on the amount of DMT extracted, since Schroeder (1989) did not report on this
compound.

None of the four compounds of interest could be extracted from the CPET tray
because of the low temperatures attained by the corn oil. The highest temperature
attained by the corn oil at the interface of the CPET tray (81.9°C) was below the glass
transition temperature of the PET, which is about 980°C. At this temperature, migrants
could remain bound to the crystalline polymer instead of diffusing into the contacting
phase.

CHAPTER 5

SUMMARY AND CONCLUSIONS

There is a marked difference in the rate of heating of oil held in a susceptor
material and that held in the CPET tray in the microwave oven. The rate of temperature
increase of the corn oil at the interface of the susceptor material was three to four times
that of the CPET tray for the same exposure time. Over the exposure times of 1 to 7
minutes, the highest temperatures recorded at the interface of the susceptor material were
136.4°C, 186.0°C, 196.6°C, 205.4°C, 217.8°C, 225.0°C, and 244.8°C, respectively. In
contrast, the highest temperatures of the corn oil recorded at the interface of the CPET
tray were 34.1°C, 45.8°C. 59.9°C, 73.6°C, 78.9°C, 75.6°C, and 81.9°C, respectively.

The result of this study confirmed earlier reports concerning the structural
breakdown of the PET barrier layer of susceptor materials during prolonged exposures.
Structural breakdown of the susceptor material started after 4 minutes of exposure, at a
temperature of about 205.4°C. Extensive structural breakdown occurred after 6 and 7
minutes of exposure, judging by the number of oil stains on the paperboard layer of the
susceptor material and the cracking of the polyester layer. It is recommended that foods
held in susceptors should not be heated for more than four minutes. This is because, for
small loads, the temperature may exceed the ignition temperature of paper. After 7
minutes of exposure, the CPET did not seem to have suffered any apparent breakdown of

its structure.

67

The structural breakdown of the susceptor material appeared to have reached the
adhesive and paperboard layers. According to the Code of Federal Regulations,
adhesives can be used if they are separated from the food by a functional barrier or if
used in packages that are intended for fatty foods, the amount of adhesive in contact
should not exceed the trace amount at seams and edge exposure between packaging
laminates (Anon, 1989a). Due to structural breakdown at high temperatures, the
polyester layer can no longer provide the required barrier for the adhesive, making it
possible for the adhesive to come into contact with the food simulant.

All four compounds of interest (DMT, DET, BHET, and Cych Trimer) were
found in the extract of the corn oil heated in the susceptor material. Concentrations of
DMT, DET, Cych Trimer, and BHET increased as the temperature at the interface
increased. Maximum concentrations of the four compounds were attained within 7
minutes of exposure. The concentrations of DMT after 1 to 7 minutes of exposure were
28.1, 212.7, 326.6, 325.7, 286.3, 301.1, and 361.5 ug/dm’, respectively. The
concentrations of DET after 1 to 7 minutes of exposure were 23.2, 191.7, 194.9, 244.8,
334.0, 340.6, 343.6 ug/dm’, respectively. Concentrations of BHET after 1 to 7 minutes
were 13.6, 33.9, 32.2, 42.0. 37.7, 38.2, and 40.2 ug/dm’, respectively. Concentrations of
cyclic trimer after 1 to 7 minutes of exposure were 1060, 10950, 11030, 12120, 12330,
12020 and 12260 ug/dm’, respectively.

Regulations on the allowable levels of DMT, DET, BHET, and Cyclic Trimer
extracted from a polymer at any time-temperature condition are not yet listed under Part
177 (Indirect food additives from polymers) of the FDA’s Code of Federal Regulations
(Anon, 1989b). Therefore, the quantity of the four migrants extracted in this study could

not be compared to any standards.

68

Corn oil does not appear to be an ideal food simulant. At high temperatures, the
chromatogram of the corn oil blank extracts showed numerous peaks, suggesting that the
corn oil experienced some form of structural breakdown, especially after 4 minutes of
exposure. In addition, the breakdown products absorb at the same wavelength used to
detect the samples, making identification of the compounds of interest more difficult.

Regulations on the migration of paperboard additives at high temperature are
non-existent. The highest temperature cited in the FDA’s Code of Federal Regulations
for extractability test conditions for paperboard additives is at 250°F for 2 hours for high
temperature heat-sterilized packages (Anon, 1989c). When the extractability test
conditions were drafted, they did not expect that paper or paperboard would be subjected
to the temperatures that the susceptor material is capable of producing. It is apparent that
the temperature to which the paperboard is exposed exceeds the temperature for the
extractability test set by the FDA.

The food contact layer of the susceptor material and the CPET tray appears to be
polyethylene terephthalate, based on the similarity of the infra-red spectra profiles of the
food contact layer of the susceptor and CPET tray to the infra-red spectrum of
polyethylene terephthalate polymer.

This study dealt with a model system, rather than a real food system. The results
could be an exaggeration of what happens in a real food system, especially with respect
to the temperatures attained in the susceptor material. An ideal situation would be to use
a formulation to simulate a system that could be encountered in microwaveable foods.
As reported by Bieber et al. (1984), migration of low molecular weight substances from
plastics, adhesives or paperboard into foodstuffs is influenced by many components and

69

properties of the food, including the fat-releasing properties, pH value, and its alcohol
content. Therefore, studies comparing real foodstuffs and food simulants to establish a

more reasonable picture on the migration phenomena are needed.

70

CHAPTER 6

SUGGESTIONS FOR FURTHER RESEARCH

The following studies are recommended:

1. Identification of a different food simulant (for example a more saturated fat, or an

engineered triglyceride) that will not breakdown at high temperatures.

2. A study of the migration of adhesives and paperboard additives from the susceptor
material.

3. Identification and characterization of the unidentified peaks that were found in the

corn oil extracts of the susceptor material, perhaps by a preparative HPLC procedure.

4. Development of a different method of identification, (infra-red analysis, TLC, mass
spectroscopy, etc.) for confirmation of the peaks. This will help overcome the fact that
the HPLC method only provides constructive identification.

5. A study of migration in real food systems should be conducted so that a comparison

can be made to check on the accuracy of using model systems.

71

CHAPTER 7

LIST OF REFERENCES

Adcock, L.H., Hope, W.G., Sullivan, D.A., and Warner, AH. 1984. The migration of
non-volatile compounds from plastics. Part 3 - Further experiments with model
systems and development of the descriptive and pictorial concept of migration.
Plastics and Rubber Processing and Applications 4:53-62

Anon. 1976. FDA guidelines for chemistry and technology requirements of indirect
food additives petition. 1976. Bureau of foods, FDA, Dept. of Health, Education
and Welfare, Washington, DC.

Anon. 1987. Microwaveable foods - Industry’s response to consumer demands for
convenience. Food Technology 41(6):52-62

Anon. 1988. Food and Drug Administration looking into susceptor packaging.
Microwave World 9(2):!1

Anon. 1989a. Code of Federal Regulations, Food and Drug Administration (21 CFR,

Part 175.105). Components of ager and paperboard in contact with aqueous and
fatty foods. Revised April 1, l 8 .

Anon. 1989b. Code of Federal Regulations, Food and Drug Administration (21 CFR,
Part 177). Indirect additives from polymers. Revised April 1. 1989

Anon. 1989c. Code of Federal Regulations, Food and Drug Administration (21 CFR,
Part 176.170). Adhesives. Revised April 1, 1989

Bartsch, H., Malaveille, C., Barbiu, A., Dresil, H., Tomatis, L., and Montesano, R. 1976.

Mutagenicity and metabolism of vinyl chloride and related compounds. Environ.
Health Perspec. 17,193-198

Berek, HE. and Wickersheim, KA. 1988. Measuring temperatures in microwaveable
packages. J. Packaging Technology 2(4):l64-168

Bieber, W.D., Freytag, W., Figge, K, vom Bruck, C.G., and Rossi, L. 1984. Transfer of
additives from plastic materials into foodstuffs and into food simulants - a
comparison. Food Chem. Toxic 22(9):737-742

Bieber, W.D., Figge, K., and Koch, J. 1985. Interaction between plastic packaging
materials and foodstuffs with different fat content and fat release properties. Food
Additives and Contaminants 2(2): 1 13-124

72

Bishop, CS. and Dye, A. 1982. Microwave heating enhances the migration of
plasticizers out of plastics. J. Environmental Health Mar./Apr.(l982):231-235

Borodinsky, L. 1988. FDA perspectives on microwaveable packaging: material and
food/package interactions. Paper presented at MW Foods ’88, 1st Intl. Conf. on
Formulating Food for the Microwave Oven, Chicago, March 8-9. The Packaging
Group, Inc., Miltown, NJ.

Briston, 1H. and Katan, LL. 1974. Plastics in Contact with Food. Food Trade Press,
Ltd., London, pp. 136—150

Castle, L., Mercer, A.J., and Gilbert, 1. 1987. Migration from lasticized films into
foods. 2. Migration of di-(2-eth 1hexyl)adipate from PV films used for retail food
packaging. Food Additives Contaminants 4(4):399-406

Castle, L., Mercer, A.J., Startin, J .R., and Gilbert, J. 1988a. Migration from plasticized
films into foods. 3. Migration of phthalate, sebacate, citrate and phosphate esters
gram lfiggs used for retail food packaging. Food Additives and Contaminants

Castle, L., Mercer, A.J., and Gilbert, 1. 1988b. Migration from plasticized films into
foods. 4. Use of polymeric plasticizers and lower levels of
di-(2-ethylhexyl)adipate plasticizer in PVC films to reduce migration into foods.
Food Additives and Contaminants 5(3):277-282

Crompton, T.T. 1979. Additive migration from plastics into food. Pergamon Press,
Oxford, England

Crosby, N.T. 1981. Food Packaging Materials: Aspects of Analysis and Migration of
Contaminants. Applied Science Publishers, Ltd. London, pp 106-122

Di Pasquale, G., Di Iorio, G., Capaccioli, T., Gagliardi, P. and Verga, GR. 1978. Gas
chromatographic headspace determination of residual acrylonitrile in
acrylonitrile-butadiene—styrene resins and migration into a simulated fatty
foodstuffs liquid. J. Chromatography 160(1): 133

Dixon, L.E., Hernandez, R.J., Gray, 1., and Harte, B. 1988. Release of components from
a plastic container during microwave heating. Packaging Technology and Science
1: 1 17- 121

Giacin, LR. 1980. Evaluation of plastics packaging materials for food packaging
applications: food safety considerations. J. Food Safety 4:257-276

Giacin, JR. and Brzozowska, A. 1985. Analytical measurements of package
cgrrapozngezntngéom unintentional migrants. J. Plastic Film and Sheeting
1 1 ): -

Giam, CS. and Wong, MK. 1987. Plasticizers in food. J. Food Protection
50(9):769-782

73

Gilbert, S.G. 1976. Migration of minor constituents from food packaging materials. J.
Food Science 41(4):955

Gilbert, S.G., Miltz, J. and Giacin, J .R. 1980. Transport considerations of potential

migrants from food packaging materials. J. Food Processing and Preservation
4(1980):27-49

Gilbert, J. and Startin, J .R. 1982. Determination of acrylonitrile monomer in food
packaging materials and in foods. Food Chem. 9:243 -

Guise, W. 1986. Packaging for the microwave. Food Processing 47(7):39-40

Heath, LL. and Reilly, M. 1981. Migration of acetyl-tributylcitrate from plastic film into
poultry products during microwave cooking. Poultry Science 60:2258-2264

Hotchkiss, J .H. and Landois-Garza, J. 1987. Plastic packaging can cause aroma
sorption. Food Engineering 59(4):39, 42

Huang, HF. 1987. New product concepts in microwaveable food packaging.
Microwave World 8(6):5-7

Keefer, RM. 1986. The role of active containers in improving heating performance in
microwave ovens. Microwave World 7(11/12):11-15

Kim, H. and Gilbert, S.G. 1988. Determination of potential migrants from commercial
polyethylene terepthalate. In: Frontiers of Flavor, Proceedings of the 5th
International Flavor Conference, Porto Karras, Chalkidiki, Greece, 1-3 July, 1987.
G. Charalambous (ed)

Komolprasert, V. and Ofoli, R.Y. 1989. Mathematical modeling of microwave heating
by tshe moeéthod of dimensional analysis. J. Food Processing and Preservation
13: 7-1

Lawrence, W.H., Malick, M., Turner, J .E., Singh, A.R., and Autian, J. 1975. A
toxicological investigation of some acute short term and chronic effects of
administering di-2-ethylhexyl-phthalate (DEHP) and other phthalate esters.
Environ. Research, 9: 1-1 1

Lentz, RR. and Crossett, T.M. 1988. Food/susceptor interface temperature during
microwave heating. Microwave World 9(5):11-16

McCowin, G.L. and Brown, T.C. 1988. The FDA’s perspective on microwave
susceptors. Microwave World 9(5):4-5

McNeal, T., Brumle , W.C., Breder, C., and Sphon, LA. 1979. Gas-solid
chromatograp 'c-mass spectrometric confirmation of low levels of acrylonitrile
after distillation from food simulating solvents. J. Assoc. 017. Anal. Chem. 62:41

74

Miltz, J. and Rosen—Doody, V. 1984. Migration of styrene monomer from polystyrene
{alcglaglirérg materials into food simulants. J. Food Processing and Preservation

Mitchell, P. 1988. FDA holds 2public meeting on microwave susceptors. Food
Processing 49(11):10, 1

Mudgett, RE. 1986. Microwave properties and heating characteristics of foods. Food
Technology 40(6): 84-98

Mudgett, RE. 1989. Microwave food processing. Food Technology 50(1):117-126

Perry, M.R. 1987a. Packa ° g for the microwave oven. Part I. J. Packaging
Technology 1(3):87- 9, 92

Perry, M.R. 1987b. Packaging for the microwave oven. Part II. J. Packaging
Technology 1(4):1 14-118

Risch, SJ. 1988. Migration of toxicants, flavors and odor-active substances from
flexible packaging materials to food. Food Technology 49(7):95-102

Rosenkranz, T. and Higgins, P. 1987 . The technology of microwave-absorbing materials
for microwave packaging. Microwave World 8(6):10-15

Rothenberger, R 1987. Current product trends in microwaveable foods. Microwave
World 8(5):]2—14

Schroeder, G ..L 1989. Non-volatile extracts of PET by microwave heated corn oil or
corn oil at 232°C (450°F). James River Corporation, N eenah W1. Unpublished

report.

Schwope, A. D., Till, D.E., Ehntholt, DJ. Sidman, K. R., Whelan, R. H., Schwartz, P. S.
and Reid, R. C. 1987. Migration of BHT and Irganox 1010 from low-density
12>oly etgy legezéLDPE) to foods and food- -simulat1ng liquids. Food Chem. Toxic.

5(4): 17-

Startin, J.R, Sharman, M, Rose, MD, Parker, 1, Mercer, A.J, Castle, L, Gilbert, J. 1987.
Migration from plasticized films into foods. 1. Migration of di-(2-ethylhexyl)
adipate from PVC films durin home-use and microwave cooking. Food Additives
and Contaminants 4(4): 385-3 8

Swami, S. and Mudgett, RE. 1981. Efi‘ect of moisture and salt contents on the dielectric
lighdagror of liquid and semi-solid foods. Proceedings of the MP1 Symposium

Turpin, C. 1980. US Patent No. 4,190,757, February 26.

75

Varner, S.L., Breder, C.V. and Fazio, T. 1983. Determination of styrene migration from
food-contact polymers into margarine, using azeotropic distillation and headspace
gas chromatography. J. Assoc. 0f. Anal. Chem, 66:1067

Withey, J. R. And Collins, PG. 1978. Styrene monomer in. foods: a limited Canadian
survey, Bull. Environ. Contam. Toxicol. 19:86

Wright, B.W. 1984. PET thermoformed ovenable containers - a concept whose time has
come. SPHE Journal. Spring, pp. 19-20, 28

76

APPENDIX A1. Average temperature of corn oil heated in susceptor
material for one minute.

 

 

Time, s Temperature, °C
Trial 1 Trial 2 Trial 3 Am e
0.0 23.5 23.4 23.5 23.5
2.0 24.5 24.6 24.3 24.5
4.0 26.7 26.9 26.2 26.6
6.0 29.7 28.8 29.0 29.2
8.0 36.5 35.1 35.9 35.8
10.0 45.6 47.1 46.6 46.4
12.0 50.0 55.3 52.6 52.6
14.0 54.5 58.8 57.8 57.1
16.0 58.9 62.9 62.6 61.5
18.0 63.4 68.1 67.8 66.4
20.0 68.1 73.2 73.8 71.7
22.0 73.1 78.1 80.7 77.3
24.0 75.8 84.2 83.6 81.2
26.0 79.9 87.8 86.5 84.7
28.0 84.5 92.6 90.4 89.1
30.0 87.9 96.5 93.7 92.7
32.0 92.4 99.7 98.2 96.8
34.0 96.5 105.4 102.2 101.4
36.0 101.4 108.4 106.6 105.5
38.0 106.1 111.1 110.7 109.3
40.0 109.2 112.4 113.7 111.8
42.0 112.6 115.8 117.0 115.1
44.0 116.4 119.2 120.6 118.7
46.0 1 19.5 123.0 123.4 121.9
48.0 122.6 126.5 126.2 125.1
50.0 125.5 130.0 128.7 128.1
52.0 128.4 133.5 131.4 131.1
54.0 130.3 137.2 133.4 133.6
56.0 131.2 140.7 134.1 135.3
58.0 131.9 143.2 133.7 136.3
60.0 133.2 143.5 132.6 136.4

77

APPENDIX A2. Average temperature of corn oil heated in susceptor material for
two minutes.

 

 

Time, 8 Temperature, °C
Trial 1 Trial 2 Trial 3 Avera e
0.0 22.1 22.6 23.2 22.6
2.0 23.0 25.8 25.6 24.8
4.0 28.2 29.0 29.6 28.9
6.0 37.7 32.9 31.5 34.0
8.0 45.1 37.4 33.8 38.8
10.0 51.3 40.4 36.8 42.8
12.0 56.8 43.0 40.1 46.6
14.0 65.0 45.8 42.8 51.2
16.0 70.8 49.1 46.2 55.4
18.0 76.3 52.5 49.8 59.5
20.0 80.7 55.5 53.3 63.2
22.0 85.1 60.5 57.1 67.6
24.0 90.7 65.5 61.3 72.5
26.0 96.5 70.6 66.6 77.9
28.0 99.5 76.1 70.7 82.1
30.0 103.7 80.5 74.9 86.4
32.0 107.9 85.4 79.5 90.9
34.0 1 12.2 89.6 84.0 95.3
36.0 1 16.1 93.6 88.6 99.4
38.0 119.6 97.5 91.9 103.0
40.0 122.7 101.5 95.9 106.7
42.0 125.8 105.8 99.6 1 10.4
44.0 129.0 109.0 103.3 113.8
46.0 131.9 111.8 106.6 116.8
48.0 134.1 114.2 110.1 119.5
50.0 136.5 117.2 113.3 122.3
52.0 138.8 120.0 116.6 125.1
54.0 140.7 123.3 1 19.7 127.9
56.0 142.9 126.4 123.3 130.9
58.0 145.3 128.8 127.1 133.7
60.0 146.9 131.5 130.5 136.3
62.0 148.6 134.1 133.6 138.8
64.0 150.1 137.1 136.3 141.2
66.0 151.4 139.9 139.0 143.4
68.0 152.7 142.8 141.7 145.7
70.0 153.9 145.4 144.0 147.8
72.0 155.2 147.6 146.4 149.7
74.0 156.5 150.0 148.5 151.7
76.0 157.7 152.3 151.0 153.7
78.0 158.7 154.4 153.3 155.5

APPENDIX A2 (can’t)
80.0 159.6
82.0 161.2
84.0 162.6
86.0 164.3
88.0 165.9
90.0 167.0
92.0 168.2
94.0 169.6
96.0 170.5
98.0 171.7
100.0 172.8
102.0 173.9
104.0 174.7
106.0 175.8
108.0 177.0
1 10.0 177.7
1 12.0 178.6
1 14.0 179.8
116.0 180.6
1 18.0 181.4
120.0 182.1

156.4
158.2
160.4
162.4
164.6
166.0
167.7
170.4
172.9
174.7
175.8
167.2
178.7
180.1
181.5
182.5
183.7
184.7
186.0
186.6
187.6

78

155.8
158.5
161.3
164.1
166.3
168.4
170.3
172.1
173.7
175.0
176.6
178.0
179.9
181.2
182.6
183.7
184.7
185.8
186.6
187.5
188.4

157.3
159.3
161.4
163.6
165.6
167.1
168.7
170.7
172.4
173.8
175.1
173.0
177.8
179.0
180.4
181.3
182.3
183.4
184.4
185.2
186.0

79

APPENDIX A3. Average temperature of corn oil heated in susceptor material for
three minutes.

 

 

Time, s Temperature, °C
Trial 1 Trial 2 Trial 3 Avera e

0.0 23.2 22.9 22.7 22.9
2.0 26.4 24.7 28.6 26.6
4.0 26.8 25.3 31.8 28.0
6.0 31.5 29.5 36.5 32.5
8.0 36.2 32.3 40.4 36.3
10.0 39.3 35.3 43.8 39.5
12.0 43.3 38.3 46.9 42.8
14.0 45.8 40.9 49.5 45.4
16.0 48.5 44.0 51.8 48.1
18.0 51.2 47.7 55.0 51.3
20.0 55.2 50.8 58.3 54.8
22.0 59.7 53.7 61.3 58.2
24.0 64.3 56.9 64.9 62.0
26.0 68.8 60.0 67.9 65.6
28.0 72.7 62.9 70.9 68.8
30.0 76.2 66.5 73.5 72.1
32.0 78.9 69.1 76.3 74.8
34.0 83.1 72.8 78.5 78.1
36.0 86.9 75.9 80.9 81.2
38.0 91.2 79.3 83.8 84.8
40.0 95.5 82.8 86.3 88.2
42.0 98.6 86.1 88.3 91.0
44.0 104.7 89.8 90.9 95.1
46.0 109.2 92.6 93.7 98.5
48.0 1 15.6 96.1 97.0 102.9
50.0 1 17.7 99.8 100.9 106.1
52.0 120.0 103.2 106.4 109.9

. 54.0 123.4 107.4 110.8 113.9
56.0 126.7 111.0 115.6 117.8
58.0 130.4 114.7 119.0 121.4
60.0 135.8 118.1 123.1 125.7
62.0 140.1 122.2 126.5 129.6
64.0 143.3 125 .7 129.4 132.8
66.0 146.3 129.4 133.9 136.5
68.0 148.1 132.8 135.7 138.9
70.0 150.6 133.4 136.2 140.1
72.0 152.8 136.6 138.1 142.5
74.0 154.4 139.8 140.6 144.9
76.0 156.7 141.4 143.5 147.2
78.0 158.6 143.8 146.1 149.5
80.0 160.6 145.8 149.1 151.8

APPENDIX A3 (can’t)
82.0 162.2
84.0 163.7
86.0 165.6
88.0 167.1
90.0 168.3
92.0 169.8
94.0 171.1
96.0 172.1
98.0 172.9
100.0 174.1
102.0 175.6
104.0 176.5
106.0 177.4
108.0 177.9
1 10.0 178.8
1 12.0 179.8
114.0 180.5
1 16.0 181.0
118.0 181.5
120.0 181.8
122.0 182.4
124.0 182.8
126.0 183.0
128.0 183.0
130.0 183.5
132.0 183.9
134.0 184.4
136.0 185.2
138.0 185.6
140.0 186.2
142.0 186.7
144.0 187.3
146.0 187.9
148.0 188.3
150.0 188.9
152.0 189.0
154.0 189.1
156.0 189.9
158.0 189.9
160.0 189.9
162.0 190.3
164.0 190.6
166.0 191.0
168.0 191.1
170.0 191.4

148.3
150.7
153.6
155.9
157.3
159.9
161.9
164.1
165.7
167.4
169.4
171.1
172.2
174.0
175.3
176.8
178.2
178.6
178.8
179.3
179.6
180.1
180.9
181.2
181.8
182.4
183.0
184.1
185.0
186.0
186.9
187.8
188.6
189.4
190.1
191.0
191.6
192.4
193.1
193.3
194.0
194.4
194.7
195.1
195.6

80

152.2
155.3
157.6
160.3
162.8
165.0
166.8
168.2
169.7
171.4
172.9
174.2
175.1
176.7
177.6
178.6
179.4
180.1
181.2
182.4
183.5
184.4
185.7
186.2
187.2
187.8
188.6
188.8
189.3
189.9
190.6
191.2
191.7
192.6
192.9
193.6
194.3
194.7
195.6
196.2
196.7
197.3
197.7
198.2
198.7

154.2
156.6
158.9
161.1
162.8
164.9
166.6
168.1
169.4
171.0
172.6
173.9
174.9
176.2
177.2
178.4
179.4
179.9
180.5
181.2
181.8
182.4
183.2
183.5
184.2
184.7
185.3
186.0
186.6
187.4
188.1
188.8
189.4
190.1
190.6
191.2
191.7
192.3
192.9
193.1
193.7
194.1
194.5
194.8
195.2

APPENDIX A3 (can’t)
172.0 191.4
174.0 191.6
176.0 191.9
178.0 192.1
180.0 192.9

195.9
196.4
196.9
197.0
197.4

81

198.8
198.9
199.0
199.3
199.5

195.4
195.6
195.9
196.1
196.6

82

APPENDIX A4. Average temperature of corn oil heated in susceptor material for
four minutes.

 

 

Time, s Temperature, °C

Triall Trial 2 Trial 3 Average
0.0 23.8 23.4 23.5 23.6
2.0 25.3 25.5 25.4 25.4
4.0 28.0 29.4 28.7 28.7
6.0 30.6 31.7 30.8 31.0
8.0 33.5 34.1 33.5 33.7
10.0 35.9 36.8 35.9 36.2
12.0 38.5 39.8 38.4 38.9
14.0 41.6 42.5 36.5 40.2
16.0 44.6 46.1 39.6 43.4
18.0 47.5 49.3 42.5 46.4
20.0 50.7 52.6 45.6 49.6
22.0 53.6 55.8 48.4 52.6
24.0 56.1 58.5 51.0 55.2
26.0 59.9 61.6 54.4 58.6
28.0 63.2 64.2 57.3 61.6
30.0 66.2 67.2 60.3 64.6
32.0 69.2 70.2 63.4 67.6
34.0 72.4 72.9 66.3 70.5
36.0 75.2 75.8 69.0 73.3
38.0 78.1 78.9 72.3 76.4
40.0 81.6 82.6 75.8 80.0
42.0 84.8 85.5 78.8 83.0
44.0 87.9 88.2 81.8 86.0
46.0 90.9 91. 85.0 89.2
48.0 94.2 94.3 87.9 92.1
50.0 97.2 97.3 90.9 95.1
52.0 100.6 100.9 94.4 98.6
54.0 104.9 104.4 98.0 102.4
56.0 109.0 107.9 101.6 106.2
58.0 112.4 111.1 104.8 109.4
60.0 115.5 114.1 107.9 112.5
62.0 118.3 117.3 110.9 115.5
64.0 121.3 121.0 114.3 118.9
66.0 125.9 125.5 118.8 123.4
68.0 130.3 129.6 123.0 127.6
70.0 134.5 133.9 126.9 131.8
72.0 139.2 137.2 130.6 135.7
74.0 143.7 140.4 134.1 139.4
76.0 146.6 143.8 137.2 142.5
78.0 148.4 147.7 140.7 145.6
80.0 151.8 130.3 151.8 144.6

APPENDIX A4 (can’t)
82.0 153.8
84.0 155.3
86.0 157.6
88.0 160.3
90.0 163.0
92.0 165.0
94.0 167.4
96.0 168.9
98.0 170.7
100.0 171.5
102.0 172.1
104.0 173.6
106.0 175.0
108.0 176.3
1 10.0 177.3
1 12.0 178.6

114.0 180.0
116.0 180.8
118.0 181.7
120.0 182.8
122.0 183.7
124.0 184.6
126.0 185.3
128.0 185.9
130.0 186.3
132.0 187.2
134.0 187.7
136.0 188.4
138.0 188.9
140.0 189.4
142.0 189.9
144.0 190.3
146.0 190.4
148.0 191.3
150.0 191.7
152.0 192.4
154.0 192.9
156.0 193.4
158.0 193.7
160.0 193.9
162.0 194.0
164.0 104.3
166.0 194.5
168.0 194.4
170.0 194.8
172.0 194.9
174.0 195.1

153.1
154.7
157.6
160.4
163.2
165.0
167.1
169.7
170.9
171.7
173.4
174.7
175.5
176.4
177.4
178.5
179.9
181.2
182.4
183.5
184.3
185.0
185.8
186.4
187.4
188.1
188.9
189.4
189.9
189.9
190.2
190.4
190.9
191.1
191.6
191.5
191.6
192.5
193.0
193.3
193.7
194.1
194.3
194.2
194.6
195.0
195.4

83

147.1
149.7
153.0
155.8
158.2
160.6
162.8
164.6
166.4
167.8
169.5
171.1
172.6
173.9
175.1
176.2
177.3
178.5
179.7
180.9
181.8
182.7
178.9
179.5
180.2
180.9
181.6
182.2
182.9
183.1
183.9
184.5
187.1
187.7
188.3
188.9
189.4
190.2
190.4
191.0
192.0
192.3
192.7
193.2
193.4
193.7
194.0

151.3
153.2
156.1
158.8
161.5
163.5
165.8
167.7
169.3
170.3
171.7
173.1
174.4
175.5
176.6
177.8
179.1
180.2
181.3
182.4
183.3
184.1
183.3
183.9
184.6
185.4
186.1
186.7
187.2
187.5
188.0
188.4
189.5
190.0
190.5
190.9
191.3
192.0
192.4
192.7
193.2
163.6
193.8
193.9
194.3
194.5
194.8

APPENDIX A4 (can’t)
176.0 195.0
178.0 195.3
180.0 195.7
182.0 196.0
184.0 196.4
186.0 196.8
188.0 197 .3
190.0 197 .7
192.0 198.1
194.0 198.0
196.0 198.4
198.0 198.9
200.0 199.4
202.0 199.9
204.0 200.2
206.0 200.1
208.0 200.5
210.0 200.8
212.0 201.2
214.0 201.7
216.0 202.0
218.0 202.4
220.0 202.8
222.0 203.1
224.0 203.4
226.0 203.9
228.0 204.1
230.0 204.0
232.0 204.3
234.0 204.6
236.0 205.0
238.0 205.3
240.0 205.9

195.8
196.2
196.5
196.6
196. 9
197 .0
197.6
198.1
198.5
198.8
199.3
199.6
199.8
200. 2
200 .0
200. 5
200. 9
201.3
201.6
210.9
202.2
202.7
203.0
203.4
203.7
204.1
204.6
204. 5
205 .0
205.4
205 .9
206.3
206.8

84

194.5
194.8
195.0
195.4
195.5
195.8
196.0
196.4
196.8
197.0
197.5
197.7
197.9
198.2
198.2
198.6
198.9
199.2
199.5
202.7
199.9
200.3
200.6
200. 8
200. 9
201.1
201.4
201.5
201.8
202.1
202.6
203.0
203.4

85

APPENDIX A5. Average temperature of corn oil heated in susceptor material for
five minutes.

 

Time, 8 Temperature, °C
Trial 1 Trial 2 Trial 3 Avera c

0.0 20.6 20.3 21.7 20.9
2.0 20. 7 20.3 21.9 21.0
4.0 23. 6 21.4 26.5 23.8
6.0 26. 6 23.7 32.0 27.4
8.0 30.2 26.2 38.6 31.7
10.0 33.0 28.9 47.7 36.5
12.0 36.1 32.2 59.5 42.6
14.0 38. 4 35.6 68.2 47.4
16.0 40. 3 38.1 75.3 51.2
18.0 43. 3 39.4 81.7 54.8
20.0 45 .5 42.8 89.1 59.1
22.0 47.6 46.6 94.3 62. 8
24.0 49.7 49.9 100.0 66. 5
26.0 52.1 52.7 103.6 69. 4
28.0 54.4 55.6 107.4 72. 5
30.0 56. 5 58.2 111.1 75.3
32.0 59. 3 61.1 114.7 78.4
34.0 61. 8 64.5 118.0 81.4
36.0 63.3 67.5 121.2 84.0
38.0 65.7 70.2 123.4 86.4
40.0 67.8 72.1 125.5 88.4
42.0 69.6 75.5 128.4 91.1
44.0 71.2 79.1 130.9 93.7
46.0 72. 8 82.1 131.9 95.6
48.0 74. 8 85.1 132.5 9‘7. 5
50.0 77. 3 87.8 133.9 99. 7
52.0 79.0 89.8 134.9 101.2

. 54.0 81.0 91.3 135.8 102. 7
56.0 82.5 93.8 137.8 104.7
58.0 84.5 95.7 139.0 106. 4
60.0 86.1 97 .7 140.7 108. 2
62.0 87.2 100.6 142.1 1100
64.0 88.7 103.3 144.2 112.1
66.0 89.8 105.2 146.7 113.9
68.0 91.4 106.8 148.3 115.5
70.0 92.9 109.8 150.0 117.6
72.0 94.7 111.7 151.9 119. 4
74.0 95.9 113.4 153.5 120. 9
76.0 97.5 115.9 155.5 123 .0
78.0 98.9 118.6 157.3 124 .9
80.0 100.5 120.4 159.4 126. 8

APPENDIX A5 (con’t)
82.0 101.6
84.0 103.0
86.0 104.8
88.0 106.3
90.0 108.1
92.0 109.8
94.0 111.6
96.0 112.7
98.0 114.4
100.0 116.2
102.0 118.1
104.0 120.2
106.0 1212
108.0 122.4
110.0 122.9
112.0 124.2
114.0 125.7
116.0 126.8
118.0 128.1
120.0 129.5
122.0 130.8
124.0 131.8
126.0 132.3
128.0 133.9
130.0 134.5
132.0 135.3
134.0 136.4
136.0 137.6
138.0 137.9
140.0 138.6
142.0 140.0
144.0 141.0
146.0 142.1
148.0 143.4
150.0 1442
152.0 145.5
154.0 146.8
156.0 148.3
158.0 149.4
160.0 150.1
162.0 151.3
164.0 152.4
166.0 153.1
168.0 154.5
170.0 155.7
172.0 156.8
174.0 157.7

122.3
124.7
126.6
128.9
130.8
132.5
133.6
135.2
137.3
138.9
141.0
141.8
144.0
145.9
147.9
149.3
150.3
152.0
153.3
152.9
154.2
155.7
147.5
158.3
158.9
160.5
162.1
164.0
165.6
167.2
168.8
170.0
171.1
172.2
174.1
175.4
176.5
177.2
179.0
180.2
181.5
183.0
184.3
185.6
186.3
187.0
188.4

86

160.3
161.1
162.1
162.9
163.6
164.2
165.3
166.1
166.9
167.5
169.3
171.0
173.2
175.2
176.5
177.8
178.4
179.2
180.2
181.5
182.5
184.0
185.5
186.2
187.7
188.2
189.3
189.9
190.4
190.9
191.2
191.9
192.5
193.2
194.4
195.4
195 .9
196.3
197.0
198.1
199.3
200.0
200.5
201.1
201.6
202.2
202.9

128.0
129.6
131.2
132.7
134.1
135.5
136.8
138.0
139.5
140.8
142.8
144.3
146.1
147.8
149.1
150.4
151.5
152.7
153.8
154.6
155.8
157.1
155.1
159.4
160.4
161.3
162.6
163.8
164.6
165.6
166.7
167.6
168.5
169.6
170.9
172.1
173.1
173.9
175.1
176.1
177.4
178.5
179.3
180.4
181.2
182.0
183.0

APPENDD( A5 (can’t)
176.0 158.7
178.0 159.8
180.0 160.6
182.0 161.8
184.0 163.2
186.0 164.1
188.0 164.9
190.0 165.9
192.0 166.8
194.0 167.8
196.0 168.4
198.0 169.0
200.0 169.9
202.0 170.5
204.0 171.1
206.0 171.8
208.0 172.8
210.0 173.4
212.0 173.8
214.0 174.7
216.0 175.3
218.0 176.2
220.0 177.1
222.0 177.9
224.0 178.6
226.0 179.2
228.0 180.0
230.0 180.8
232.0 181.3
234.0 182.2
236.0 182.9
238.0 183.8

240.0 184.5
242.0 185.5
244.0 186.7
246.0 187 .6
248.0 188.9
250.0 190.1
252.0 191.0
254.0 192.3
256.0 193.2
258.0 194.3
260.0 195.0
262.0 196.6
264.0 197.2
266.0 198.4
268.0 199.3

189.5
190.5
191.4
192.6
193.6
195.0
195 .8
197 .7
198.9
199.7
200.3
201.1
201.5
202.3
202.9
203.6
204.1
204.5
205.0
205.4
205.6
205.8
205.8
206.2
206.5
206.9
207.5
208.1
208.4
208.7
208.9
209.2
209.5
209.6
209.7
209.9
210.2
210.5
210.6
210.8
21 1.0
21 1.3
21 1.4
21 1.6
21 1.8
212.1
212.5

87

203.2
204.1
204.8
205.2
205.6
205.9
206.3
206.7
207.1
207.7
208.2
208.6
209.0
209.8
210.3
210.7
210.6
210.8
211.2
211.7
212.1
212.2
212.5
212.9
212.8
213.3
213.6
213.7
213.9
214.3
214.6
214.9
215.3
215.5
215.8
216.1
216.7
216.9
217.3
217.9
218.3
218.7
219.3
219.2
219.4
219.8
220.0

§§§

N
8.5:

LbbiflbbmwMHMHaL‘hNo-F

EE§§§§§§§§§§§§§§
aid-33

APPENDIX A5 (can’t)
270.0 200.1
272.0 201.6
274.0 202.3
276.0 203.2
278.0 204.1
280.0 204.8
282.0 205.7
284.0 206.2
286.0 207.0
288.0 207 .5
290.0 208.8
292.0 209.7
294.0 210.3
296.0 21 1.1
298.0 212.1
300.0 212.6

212.6
212.9
213.2
213.5
213.7
214.0
214.2
214.3
214.4
214.6
214.8
215.0
215.1
214.1
215.4
215.7

88

220.3
220.2

220.4 .

220.7
220.9
221.3
221.4
221.8
222.1
222.7
222.9
223.1
223.7
224.2
224.8
225.3

211.0
211.6
212.0
212.5
212.9
213.3
213.8
214.1
214.5
214.9
215.5
215.9
216.3
216.5
217.4
217.8

89

APPENDIX A6. Average temperature of corn oil heated in susceptor material for
six minutes.

 

 

Time, 8 Temperature, °C
Trial 1 Trial 2 Trial 3 Average
0.0 23.1 22.2 23.0 22.8
2.0 23.3 22.2 23.3 22.9
4.0 27.6 24.3 27.0 26.3
6.0 33.3 28.0 30.4 30.6
8.0 37.3 31.0 33.1 33.8
10.0 40.9 33.5 36.1 36.8
12.0 43.0 35.5 38.1 38.9
14.0 46.4 38.5 41.6 42.2
16.0 50.5 42.9 44.0 45 .8
18.0 55.8 47.4 47.3 50.2
20.0 61.8 52.8 50.3 55.0
22.0 68.0 57.6 58.8 61.5
24.0 74.4 61.6 62.2 66.1
26.0 80.8 65.6 68.2 71.5
28.0 87.3 69.6 72.8 76.6
30.0 92.6 73.1 79.0 81.6
32.0 97.7 76.4 83.6 85.9
34.0 102.0 79.3 85.2 88.8
36.0 107.0 82.9 88.4 92.8
38.0 111.2 85.5 94.6 97.1
40.0 114.1 87.9 99.6 100.5
42.0 1 17 .0 90.1 103.3 103.5
44.0 120.7 93.0 107 .4 107.0
46.0 123.6 95.1 111.1 109.9
48.0 125.7 97.1 117.3 113.4
50.0 128.7 99.6 120.9 116.4
52.0 131.9 102.9 125 .7 120.2
54.0 135.5 105.1 129.2 123.3
56.0 138.1 107.1 133.0 126.1
58.0 140.4 108.0 135.4 127.9
60.0 143.0 108.3 137.8 129.7
62.0 145.4 108.7 139.4 131.2
64.0 147.3 109.2 141.9 132.8
66.0 148.6 109.8 143.6 134.0
68.0 150.7 1 10.0 145.1 135.3
70.0 152.4 110.6 148.8 137.3
72.0 154.0 1 1 1.1 150.9 138.7
74.0 155.3 111.9 152.8 140.0
76.0 156.8 112.2 154.9 141.3
78.0 158.3 112.6 157.3 142.7
80.0 159.1 1 13.7 159.0 143.9

APPENDIX A6 (can’t)
82.0 159.9
84.0 160.7
86.0 162.1
88.0 163.4
90.0 165.0
92.0 166.6
94.0 167.8
96.0 169.0
98.0 170.3
100.0 171.2
102.0 172.1
104.0 173.4
106.0 174.8
108.0 175.9

1 10.0 176.6
1 12.0 177.4
1 14.0 178.4
116.0 179.0
118.0 179.6
120.0 180.1
122.0 181.0
124.0 181.6
126.0 182.3
128.0 182.6
130.0 183.0
132.0 183.4
134.0 183.8
136.0 184.2
138.0 185.0
140.0 185.7
142.0 185.5
144.0 185.9
146.0 186.1
148.0 186.6
150.0 187.0
152.0 186.9
154.0 187.3
156.0 188.2
158.0 188.9
160.0 189.2
162.0 189.0
164.0 189.4
166.0 189.8
168.0 190.3
170.0 191.2
172.0 191.6

114.9
116.2
118.2
119.8
121.4
123.5
124.3
125.8
126.8
128.0
129.4
132.9
133.3
134.4
135.2
135.5
137.3
138.0
138.6
138.9
139.1
139.6
139.9
140.3
140.4
141.4
141.7
142.3
143.0
144.2
144.2
145.0
146.1
147.5
148.6
151.1
152.6
154.4
155.7
157.6
160.0
161.5
162.6
163.4
164.3
165.2

160.8
162.3
163.8
165.2
166.6
168.5
170.2
171.3
171.9
173.1
173.6
174.1
174.7
175.4
176.8
177.5
177.9
179.0
179.7
180.4
181.1
181.9
182.5
183.1
184.3
185.3
186.1
186.5
187.2
187.8
188.1
188.7
189.2
189.6
190.1
190.5
191.1
191.6
192.0
192.9
193.5
194.1
194.7
195.2
195.4
195.5

145.2
146.4
148.0
149.5
151.0
152.9
154.1
155.4
156.3
157.4
158.4
160.1
160.9
161.9
162.9
163.5
164.5
165.3
166.0
166.5
167.1
167.7
168.2
168.7
169.2
170.0
170.5
171.0
171.7
172.6
172.6
173.2
173.8
174.6
175.2
176.2
177.0
178.1
178.9
179.9
180.8
181.7
182.4
183.0
183.6
184.1

APPENDIX A6 (con’t)
174.0 192.0
176.0 191.9
178.0 192.3
180.0 192.9
182.0 193.3
184.0 193.6
186.0 193.4
188.0 193.7
190.0 194.0
192.0 194.4
194.0 194.9
196.0 195.3
198.0 195.2
200.0 195.1
202.0 195.3
204.0 195.6
206.0 196.0
208.0 196.5
210.0 196.7
212.0 197.2
214.0 197.5
216.0 198.1
218.0 198.4
220.0 198.8
222.0 199.2
224.0 199.7
226.0 200.2
228.0 200.7
230.0 201.1
232.0 201.0
234.0 201.1
236.0 201.4
238.0 201.9

' 240.0 202.5
242.0 202.9
244.0 203.4
246.0 203.8
248.0 204.1
250.0 204.6
252.0 204.9
254.0 205.3
256.0 205.2
258.0 205.7
260.0 205.9
262.0 206.1
264.0 206.9

165.8
166.2
166.9
167.3
167.8
168.4
168.9
169.7
169.5
169.9
170.4
171.8
172.1
172.9
173.3
173.9
174.5
174.8
174.7
175.2
175.9
176.9
177.4
177.9
178.3
178.8
179.4
179.7
180.1
179.9
180.3
180.7
181.1
181.0
181.4
182.1
182.8
183.3
184.2
184.7
185.0
185.7
186.6
187.4
188.2
189.1

91

195.8
196.2
196.5
196.4
196.9
197 .2
197.6
197.4
197.9
198.2
198.7
198.9
199.2
199.7
200.2
200.3
200.5
201.6
201.9
202.5
203.4
203 .9
203.9
204.1
204.6
205.3
205 .9
206.0
205 .9
206.3
207 .0
207 .5
207.9
208.2
208.5
209.1
209.8
210.3
210.7
21 1.1
21 1.7
21 1.9
212.2
212.6
212.7
213.0

§§§§§§§
bububuh

APPENDIX A6 (can’t)
266.0 207.2
268.0 207 .7
270.0 208.1
272.0 208.7
274.0 209.0
276.0 208.9

. 278.0 209.4
280.0 209.8
282.0 210.3
284.0 210.8
286.0 21 1.4
288.0 212.0
290.0 212.5
292.0 212.9
294.0 213.4
296.0 213.9
298.0 214.5
300.0 215.1
302.0 215.0
304.0 215.6
306.0 216.1
308.0 216.9
310.0 217.3
312.0 217 .8
314.0 218.3
316.0 219.0
318.0 219.5
320.0 219.4
322.0 219.8
324.0 220.2
326.0 220.5
328.0 220.8
330.0 220.7
332.0 221.0
334.0 221.5
336.0 221.9
338.0 222.4
340.0 222.8
342.0 223.1
344.0 223.6
346.0 223.9
348.0 224.3
350.0 224.2
352.0 224.7

189.5
190.0
190.3
191.5
192.3
193.0
193.6
194.2
194.9
195.5
196.0
196.5
197.1
197.8
198.4
198.9
199.4
200.1
200.7
201.5
202.1
202.8
203.3
204.7
205.3
205.9
206.4
207.0
207.6
208.1
208.9
209.4
209.9
210.3
210.8
21 1.5
21 1.8
212.3
212.7
213.0
214.4
214.9
215.0
215.5

92

213.5
213.9
214.2
214.8
215.5
216.1
216.0
216.4
216.8
217.3
217.7
218.0
218.4
218.8
219.1
219.6
219.7
220.0
221.3
221.8
222.4
222.8
223.4
223.9
224.3
224.3
224.6
224.9
225.2
225.5
225.9
226.1
226.5
226.7
226.6
227.0
227.1
227.6
228.0
228.2
228.6
229.1
229.4
229.7

bbhoh&bbbbboh

NNNNNNNNN N” N N
35;;55888§33§§8§8§§§
OWQNQWW

213.

214.2
214.7
215.5
216.0
216.4
216.8
217.1
217.5
217.9
218.4
218.8
219.0
219.3
219.6
220.1
220.4
220.9
221.3
221.6
222.3
222.8
222.9
223.3

APPENDIX A6 (can’t)
354.0 225.0
356.0 225.2
358.0 225.8
360.0 226.1

216.1
216.9
217.7
218.3

93

230.1
230.2
230.5
230.7

E§§§
bhbh

94

APPENDIX A7. Temperature profile of corn oil heated in susceptor material for
seven minutes.

 

T1me, 8 Temperature. °C
Trial 1 Trial 2 Trial 3 Average
0.0 23.3 23.5 23.1 23.3
2.0 26.2 25.7 24.1 25.3
4.0 29.7 28.9 28.0 28 .9
6.0 35.2 33.3 36.1 34.8
8.0 38.8 38.5 41.6 39.6
10.0 41.8 41.9 45.3 43.0
12.0 45 .1 45.8 48.9 46.6
14.0 49.8 50.9 53.3 51.4
16.0 54.4 56.6 59.7 56.9
18.0 60.0 61.3 65.6 62.3
20.0 64.1 67.5 75.0 68.8
22.0 67.7 72.9 78.4 73.0
24.0 71.7 78.0 83.1 77.6
26.0 76.5 83.2 88.4 82.7
28.0 80.9 87.8 93.0 87.2
30.0 84.7 92.3 98.5 91.8
32.0 88.2 96.5 104.6 96.4
34.0 92.4 100.7 109.1 100.7
36.0 97.8 105.2 111.8 104.
38.0 101.7 109.2 115.4 108.8
40.0 105.0 1 12.9 120.7 112.9
42.0 107.9 115.8 123.2 115.6
44.0 111.8 118.2 125.5 118.5
46.0 1 15.1 120.4 127.1 120.9
48.0 117.6 122.5 129.3 123.1
50.0 120.3 124.7 131.8 125.6
52.0 122.4 126.9 133.7 127.7
54.0 124.6 129.1 135.8 129.8
56.0 126.6 131.1 137.7 131.8
58.0 128.5 133.2 139.2 133.6
60.0 130.4 134.6 140.8 135.3
62.0 133.7 136.5 142.9 137.7
64.0 136.4 138.3 144.4 139.7
66.0 139.1 140.0 146.2 141.8
68.0 138.3 141.7 147.7 142.6
70.0 142.6 143.7 150.3 145.5
72.0 144.2 145.6 152.3 147.4
74.0 146.3 147.1 153.6 149.0
76.0 148.6 148.2 154.1 150.3
78.0 149.9 149.5 155.1 151.5
80.0 152.0 150.9 156.2 153.0

APPENDIX A7 (con’t)
82.0 153.9
84.0 155.6
86.0 157.4
88.0 158.6
90.0 159.8
92.0 160.9
94.0 161.9
96.0 163.1
98.0 164.5
100.0 165.7
102.0 166.4
104.0 167.5
106.0 168.8
108.0 169.8
110.0 170.7
112.0 171.7
114.0 172.4
116.0 173.1
118.0 1742
120.0 1752
122.0 175.9
124.0 176.5
126.0 177.2
128.0 178.2
130.0 178.8
132.0 179.7
134.0 180.5
136.0 181.7
138.0 183.0
140.0 183.9
142.0 184.6
144.0 185.3
146.0 186.1
148.0 187.1
150.0 187.8
152.0 188.5
154.0 189.3
156.0 190.0
158.0 190.5
160.0 191.3
162.0 192.0
164.0 192.5
166.0 193.3
168.0 193.8
170.0 194.2
172.0 194.7
174.0 195.4

152.0
153.2
154.4
155.3
156.2
157.1
158.1
159.2
160.7
161.7
162.6
163.3
163.7
164.6
165.1
165.9
166.6
167.4
168.1
168.8
169.5
170.2
170.8
171.3
171.9
172.5
173.0
173.3
173.7
174.3
174.9
175.2
175.7
176.1
176.7
177.3
178.0
178.6
179.1
179.6
180.0
180.5
180.9
181.5
182.0
182.4
183.1

95

157.1
158.1
159.0
160.1
160.9
161.7
162.5
163.7
165.3
166.2
166.8
167.3
167.8
168.6
168.9
169.4
169.9
170.4
170.6
171.2
171.7
172.4
172.8
173.6
173.9
174.9
175.3
175.6
176.2
177.0
177.9
178.3
179.0
179.5
180.3
181.1
181.9
182.7
183.0
183.5
184.0
184.6
185.0
185.8
186.4
186.9
187.6

154.3
155.6
156.9
158.0
159.0
159.9
160.8
162.0
163.5
164.5
165.3
166.0
166.8
167.7
168.2
169.0
169.6
170.3
171.0
171.7
172.4
173.0
173.6
174.4
174.9
175.7
176.3
176.9
177.6
178.4
179.1
179.6
180.3
180.9
181.6
182.3
183.1
183.8
184.2
184.8
185.3
185.9
186.4
187.0
187.5
188.0
188.7

APPENDIX A7 (con’t)
176.0 196.3
178.0 197.0
180.0 197.9
182.0 198.7
184.0 199.7
186.0 200.5
188.0 201.4
190.0 202.6
192.0 203.2
194.0 204.1
196.0 204.7
198.0 205.6
200.0 206.3
202.0 207.4
204.0 207 .9
206.0 208.8
208.0 209.6
210.0 210.7
212.0 21 1.2
214.0 21 1.5
216.0 212.0
218.0 212.2
220.0 212.4
222.0 212.7
224.0 212.8
226.0 213.0
228.0 213.3
230.0 213.6
232.0 213.9
234.0 214.1
236.0 214.4
238.0 214.7
240.0 215.1
242.0 215.7
244.0 215.9
246.0 216.1
248.0 216.5
250.0 216.7
252.0 217.1
254.0 217.2
256.0 217.4
258.0 217.7
260.0 218.0
262.0 218.3
264.0 218.5
266. 0 218.8
268 .0 219.1

183. 5
184. 0
184. 5
185 .0
185.4
186.0
186.4
186.7
187.4
188.1
188.7
189.2
189.7
190.1
190.5
191.0
191.5
192.0
192.4
193.0
193.3
193.8
194.3
194.8
195.3
195.9
196.4
196.9
197.2
197.6
197.9
198.2
198.7
199.2
199.5
200.0
200.5
201. 1
201.6
202. 1
202.6
203.1
203.5
204. 0
204. 5
205 .0
205.6

96

187.9
188.2
188.6
189.1
189. 8
190. 3
190. 8
191.2
191.7
192.3
192.7
193.5
193.9
194.1
194.5
194.8
195.4
196.0
196.6
197.0
197.4
197.5
198.0
198.5
198.9
199.5
200.2
200.7
201.2
201.6
202.2
202.3
202.6
203.1
203.0
203.3
203.8

204. 9
205.5
206. 0
206.4
206.9
207 .2
207. 8
208. 3
208 .9

203.8

§§§§§§§§§§§§§§§§
bhbbifiqucwcu—ouwmhu

NNN
t-‘O-III-h
HOG

APPENDIX A7 (can’t)
270.0 219.4
272.0 219.6
274.0 219.8
276.0 220.1
278.0 220.2
280.0 220.5
282.0 220.6
284.0 221.0
286.0 221.3
288.0 221.5
290.0 221.6
292.0 221.9
294.0 222.1
296.0 222.4
298.0 222.6
300.0 223.0
302.0 223.7
304.0 223.9
306.0 224.1
308.0 224.3
310.0 224.5
312.0 224.8
314.0 225.4
316.0 225.5
318.0 225.8
320.0 226.1
322.0 226.4
324.0 226.6
326.0 226.8
328.0 227.0
330.0 227.4
332.0 227.6

. 334.0 227.9
336.0 228.0
338.0 228.3
340.0 228.6
342.0 228.8
344.0 229.0
346.0 229.2
348.0 229.5
350.0 229.7
352.0 229.9
354.0 230.1
356.0 230.4
358.0 230.7
360.0 230.9
362.0 231.1

2838888

:88

97

21 1.6
212.0
212.3
212.6
213.0
213.3
213.7
214.2
214.5
214.9
215.3
215.7
216.1
216.5
216.8
217.3
217.9
218.2
218.6
219.1
219.6
220.0
220.5
220.9
221.3
221.7
222.1
222.4
222.8
223.3
223.7
224.1
224.5
224.9
225.3
225.7
226.2
226.6
227.0
227.4
227.9
228.6
229.1
229.5
230.4
230.9
231.4

APPENDIX A7 (con’t)
364.0 231.5
366.0 231.7
368.0 232.0
370.0 232.2
372.0 232.4
374.0 232.7
376.0 232.9
378.0 233.2
380.0 233.4
382.0 233.5
384.0 233.7
386.0 234.0
388.0 234.3
390.0 234.4
392.0 234.7
394.0 235.1
396.0 235.4
398.0 235.6
400.0 235.5
402.0 235.9
404.0 236.2
406.0 236.4
408.0 236.6
410.0 236.9
412.0 237.1
414.0 237.4
416.0 237.5
418.0 237.8
420.0 238.1

229.7
230.2
230.6
231.2
231.6
232.2
232.7
233.3
233.8
234.4
234.8
235.2
235.7
236.2
236.7
237.2
237.7
238.2
238.8
239.4
240.0
240.5
241.1
232.5
242.0
242.5
243.0
243.6
244.2

98

234.8
235.5
236.0
236.7
237.4
238. 1
238.9
239.6
240.3
240.9
241 .5
241 .8
242.5
243.0
243.6
244.2

245.4
246.0
246.8
247.6
248.2
248.9
249.3
249.8
250.3
250.8
25 1.5
252.0

tAfiPPENDIX A8. Average temperature of corn oil heated in CPET tray for one
nute.

 

Time, 8 Temperature, °C
Trial 1 Trial 2 Trial 3 Average
0.0 21.7 22.3 21.7 21.9
4.0 22.8 23.8 22.6 , 23.0
8.0 23.8 25.2 23.4 24.1
12.0 24.8 26.3 24.1 25.1
16.0 25.6 27.6 24.9 26.0
20.0 26.4 28.8 25.9 27.0
24.0 27.1 29.9 26.3 27.8
28.0 27.8 30.9 27.0 28.5
32.0 28.5 31.9 27.6 29.3
36.0 29.3 33.0 28.2 30.1
40.0 29.7 34. 28.9 30.9
44.0 30.3 35.0 29.3 31.5
48.0 31.0 36.0 29.9 32.3
52.0 31.5 36.9 30.6 33.0
56.0 32.2 37.9 31.1 33.7
60.0 32.3 38.8 31.8 34.3

100

lAfil’g’ENDIX A9. Average temperature of corn oil heated in CPET tray for two
utes.

 

Time, 8 Temperature, “C
Trial 1 Trial 2 Trial 3 Avera e

0.0 23.3 23.4 22.7 23.1
4.0 23.5 24.8 23.9 24.1

8.0 23.7 25.4 25.1 24.7
12.0 23.8 26.5 26.1 25.5
16.0 23.9 27.4 26.9 26.1
20.0 25.0 28.5 27.7 27.0
24.0 26.2 29.2 28.7 28.0
28.0 27.4 30.2 29.4 29.0
32.0 28.3 31.1 30.4 29.9
36.0 29.3 31.9 31.2 30.8
40.0 30.1 32.7 32.4 31.7
44.0 31.0 33.5 33.1 32.5
48.0 31.9 34.2 34.2 33.4
52.0 32.7 34.7 35.0 34.1
56.0 33.6 35.6 35.7 34.9
60.0 34.4 36.4 36.7 35.8
64.0 35.3 37.4 37.4 36.7
68.0 36.1 37.9 38.2 37.4
72.0 37.0 38.8 39.0 38.3
76.0 37.2 39.7 39.6 38.8
80.0 38.1 40.4 40.3 39.6
84.0 38.8 41.2 41.1 40.4
88.0 39.2 42.0 42.0 41.1
92.0 38.8 42.5 42.6 41.3
96.0 39.2 43.0 43.1 41.8
100.0 40.5 43.6 43.7 42.6
104.0 41 6 44.2 44.4 43.4
108.0 43.1 44.7 45.1 44.3
112.0 44.0 45.1 45.7 44.9
1 16.0 44.6 45 .4 46.5 45.5
120.0 45 1 45.9 46.4 45.8

101

hAflP'IENDIX A10. Average temperature of corn oil heated in CPET tray for three
utes.

 

Time, 8 Temperature, °C
Trial 1 Trial 2 Trial 3 Average

0.0 23.8 25.1 23.1 24.0
4.0 25.3 25.8 24.7 25.3

8.0 27 .1 27.3 26.3 26.9
12.0 28.6 28.8 27.5 28.3
16.0 30.1 29.9 28.5 29.5
20.0 31.7 31.1 30.2 31.0
24.0 33.0 32.1 31.4 32.2
28.0 34.3 33.1 32.8 33.4
32.0 35.6 34.1 34.0 34.5
36.0 36.8 34.9 34.9 35.5
40.0 38.0 35.8 35.6 36.4
44.0 39.1 36.7 37.0 37.6
48.0 40.0 37.6 37.9 38.5
52.0 41.2 38.6 38.9 39.6
56.0 42.2 39.6 39.9 40.6
60.0 43.5 40.5 41.1 41.7
64.0 44.6 41.4 41.9 42.6
68.0 45.5 42.2 43.1 43.6
72.0 46.6 43.0 44.1 44.6
76.0 47.6 43.7 45.1 45.5
80.0 48.7 44.3 45.8 46.2
84.0 49.7 44.9 46.8 47.1
88.0 50.4 45 .4 47.4 47.7
92.0 51.3 46.1 48.1 48.5
96.0 52.1 46.4 48.8 49.1
100.0 52.7 46.8 50.0 49.8
104.0 53. 47.2 50.5 50.3
108.0 53.9 47.7 51.1 50.9
112.0 54.6 48.1 51.5 51.4
116.0 55.0 48.7 52.1 51.9
120.0 55.5 49.0 52.7 52.4
124.0 56.0 49.6 53.1 52.9
128.0 56.4 49.9 53.8 53.4
132.0 57.0 50.6 54.3 53.9
136.0 57.4 51.1 54.9 54.5
140.0 58.1 51.4 55.9 55.1
144.0 58.7 52.2 56.5 55.8
148.0 59.3 52.8 57.5 56.5
152.0 59.9 53.2 57.8 56.9
156.0 60.6 53.8 58.1 57.5
160.0 61.2 54.1 58.6 58.0

APPENDIX A10 (can’t)
164.0 61.7
168.0 62.2
172.0 62.6
176.0 63.1
180.0 64.1

54.8
55.2
55.5
55.9
56.4

102

59.0
59.2
59.7
59.7
59.2

58.5
58.8
59.3
59.6
59.9

103

fiPENDIx All. Average temperature of corn oil heated in CPET tray for live
utes.

 

 

Time, 3 Temperature, °C
Trial 1 Trial 2 Trial 3 Avera e

0.0 23.7 23.3 23.0 23.3
4.0 24.9 23.6 24.2 24.2
8.0 26.1 24.9 26.1 25 .7
12.0 27.3 26.1 27.8 27.1
16.0 28. 3 27.3 29.5 28. 3
20.0 29. 2 28.3 31.0 29.5
24.0 30. 3 29.2 32.5 30. 7
28.0 31. 3 30.1 34.1 31. 8
32.0 32. 2 31.1 35.7 33 .0
36.0 33.1 31.9 37.3 34.1
40.0 33.8 32.9 38.6 35.1
44.0 34. 8 33.7 40.1 36.2
48.0 35 .7 34.5 41.4 37.2
52.0 36. 5 35.3 42. 6 38.1
56.0 37.5 36.1 43.7 39.1
60.0 38.4 37 .0 45.0 40.1
64.0 39.4 37.8 46.0 41.1
68.0 40. 3 38.8 47.1 42.1
72.0 41.3 39.6 48. 3 43.0
76.0 42.1 40.5 49. 8 44.1
80.0 43.2 41.1 51.1 45.1
84.0 44.0 42.0 52.4 46.1
88.0 44. 6 42.7 53.6 47.0
92.0 45. 4 43.4 54.7 47.8
96.0 46.0 44.0 56.0 48.7
100.0 46. 4 44.6 57.2 49.4
104. 0 47 .0 45.1 58.2 50.1
- 108 .0 47. 3 45.7 59.1 50.7
112. 0 47.9 46.3 60. 2 51.4
116.0 48.5 47.1 61.0 52.2
120.0 48.9 47.9 61.9 52.9
124.0 49.4 48. 7 62.7 53.6
128.0 50.1 49. 4 63 .4 54.3
132.0 50.5 50. 2 64.0 54.9
136.0 51.0 51.1 64.5 55.5
140. 0 51.6 52.0 64. 9 56.2
144 .0 52.1 52. 9 65. 8 56.9
148. 0 52.7 53 .7 66.3 57.6
152. 0 53.0 54. 8 66.7 58.2
156.0 53.5 55. 8 67. 3 58.8
160.0 54.1 56.8 67. 8 59.5

APPENDIX A11 (con’t)
164.0 54.6
168.0 55.1
172.0 55.8
176.0 56.3
180.0 56.9
184.0 57.6
188.0 58.2
192.0 58.9
196.0 59.4
200.0 59.9
204.0 60.6
208.0 61.1
212.0 61.4
216.0 62.2
220.0 62.6
224.0 63.3
228.0 63.8
232.0 64.3
236.0 64.7
240.0 64.6

104

68.1
68.6
69.1
69.5
69.8
70.6
71.0
71.5
72.0
72.8
73.4
74.3
75.0
75.7
76.3
77.1
78.0
78.7
79.3
79.8

833$$$§$$8
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105

hAflPPFtJNDIX A12. Average temperature of corn oil heated in CPET tray for five
nu es.

 

 

Time, 8 Temperature, °C
Trial 1 Trial 2 Trial 3 Average

0.0 22.9 23.5 20.8 22.4
4.0 23.4 24.7 21.1 23.1
8.0 25.0 26.0 22.1 24.4
12.0 26.4 27.1 22.9 25.5
16.0 28.0 28.5 24.0 26.8
20.0 29.4 29.7 24.9 28.0
24.0 30.7 30.7 25.7 29.0
28.0 32.1 31.8 26.4 30.1
32.0 33.5 32.8 27.3 31.2
36.0 34.8 34.0 28.1 32.3
40.0 36.2 34.8 29.0 33.3
44.0 37.3 35.8 29.8 34.3
48.0 37.4 36.8 30.4 34.9
52.0 39.6 37.7 31.3 36.2
56.0 40.6 38.8 32.0 37.1
60.0 41.6 39.6 32.7 37.9
64.0 42.8 40.4 33.6 38.9
68.0 43.9 41.3 34.5 39.9
72.0 45.1 42.2 35.3 40.8
76.0 45.8 42.8 36.2 41.6
80.0 47.5 43.7 37.0 42.7
84.0 48.6 44.4 37.7 43.5
88.0 49.7 45.0 38.5 44.4
92.0 48.7 45.6 39.3 44.5
96.0 49.7 46.2 40.0 45.3
100.0 50.6 46.5 40.5 45.9
104.0 51.6 47.4 41.1 46.7
- 108.0 52.4 48.1 41.5 47.3
112.0 53.5 48.7 42.1 48.1
116.0 54.3 49.5 42.7 48.8
120.0 55.0 50.1 43.2 49.4
124.0 55.7 50.9 43.7 50.1
128.0 56.4 51.5 44.2 50.7
132.0 56.9 52.4 44.6 51.3
136.0 57.5 53.2 45.2 51.9
140.0 58.0 54.0 45.6 52.5
144.0 58.5 55.0 46.1 53.2
148.0 58.9 55.7 46.5 53.7
152.0 59.0 56.6 47.0 54.2
156.0 59.3 57.5 47.3 54.7
160.0 59.6 58.4 47.9 55.3

164.0
168.0
172.0
176.0
180.0
184.0
188.0
192.0
196.0
200.0

APPENDIX A12 (con’t)

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O ppgpégpppprrppppflfl. O 0 O O O O O O O 0 O O
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78.8

m
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U)
m

74.2
75.0
75.8
76.7
77.5
78.6
79.6
80.5
81.2
82.2
82.9
83.7
84.8
85.7
86.6
87.5
88.5
88.7

106

48.4
48.8
49.3
49.9
50.4
50.9
5 1.3
51.7
52.2
52.7
53.2
53.5
54.2
54.7
55.6
56.9
58.1
59.7
60.8
61.5
62.4
62.7
63.1
64.1
64.5
65.0
65.3
65.6
66.5
66.7
67.3
67.8
68.3
68.8
69.3

64.3

353.833.3383"
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71.4

107

35!:me A13. Average temperature of corn oil heated in CPET tray for six
utes.

 

Time, 8 Temperature, °C
Trial 1 Trial 2 Trial 3 Average

0.0 22.2 21.9 23.2 22.4

4.0 23.4 22.8 23.5 23.2

8.0 24.8 23.9 24.7 24.5
12.0 25.9 24.9 25.8 25.5
16.0 27.0 25.8 26.8 26.5
20.0 27.9 26.7 27.8 27.4
24.0 29.0 27.5 28.4 28.3
28.0 29.9 28.3 29.2 29.1
32.0 30.7 29.1 30.1 30.0
36.0 31.5 29.9 30.8 30.7
40.0 32.5 30.5 31.3 31.4
44.0 33.5 31.4 31.9 32.2
48.0 34.3 32.1 32.6 33.0
52.0 35.2 32.8 33.0 33.7
56.0 36.1 33.5 33.6 34.4
60.0 36.9 34.3 34.2 35.1
64.0 37.7 34.9 34.8 35.8
68.0 38.4 35.6 35.2 36.4
72.0 39.1 36.3 35.7 37.0
76.0 39.8 36.9 36.3 37.7
80.0 40.5 37.7 36.6 38.2
84.0 40.9 38.3 37.1 38.8
88.0 41.4 39.0 37.8 39.4
92.0 41 8 39.5 38.5 39.9
96.0 42 3 40.2 39.2 40.6
100.0 42 8 40.9 40.0 41.2
104.0 43 5 41.4 40.7 41.9
108.0 44 1 42.0 41.4 42.5
112.0 44 4 42.6 42.1 43.0
116.0 45 0 43.2 43.0 43.7
120.0 45 6 43.8 43.7 44.3
124.0 46 2 44.5 44.4 45.0
128.0 46 7 45.1 45.1 45.6
132.0 47 5 45.9 45.9 46.4
136.0 47 9 46.4 46.7 47.0
140.0 48 8 47.1 47.2 47.7
144.0 49 5 48.0 48.0 48.5
148.0 50 2 48.8 48.6 49.2
152.0 51 0 49.4 49.3 49.9
156.0 51 6 50.2 49.9 50.5
160.0 52 4 50.8 50.6 51.2

108

APPENDIX A13 (con’t)
164.0 53.1 51.5 51.2 51.9
168.0 53.9 52.2 51.9 52.7
172.0 54.6 52.8 52.5 53.3
176.0 55.4 53.4 53.0 53.9
180.0 56.0 54.1 53.8 54.6
184.0 56.7 54.6 54.6 55.3
188.0 57.4 55.1 55.2 55.9
192.0 58.2 55.9 55.9 56.7
196.0 58.8 56.3 56.8 57.3
200.0 59.4 56.9 57.6 58.0
204.0 60.2 57.4 58.4 58.7
208.0 60.8 58.0 59.0 59.3
212.0 61.6 58.7 59.7 60.0
216.0 62.2 59.1 60.4 60.5
220.0 62.9 59.8 61.1 61.3
224.0 63.5 60.4 61.8 61.9
228.0 64.2 61.1 62.6 62.6
232.0 64.8 61.6 63.3 63.2
236.0 65.7 62.1 63.9 63.9
240.0 66.3 62.6 64.6 64.5
244.0 67.1 63.0 65.2 65.1
248.0 67.6 63.5 65.7 65.6
252.0 68.4 64.0 66.4 66.3
256.0 69.0 64.4 66.8 66.7
260.0 69.6 64.9 67.2 67.2
264.0 70.2 65.4 67.4 67.7
268.0 71.0 66.0 67.6 68.2
272.0 71.6 66.4 67.7 68.5
276.0 72. 66.9 67.7 68.9
280.0 72.9 67.3 67.9 69.4
284.0 73.4 67.8 67.9 69.7
288.0 73.9 68.1 67.9 70.0
292.0 74.5 68.3 68.0 70.2
296.0 75.1 68.8 68.2 70.7
300.0 75.7 69.1 68.4 71.0
304.0 76.3 69.3 68.7 71.4
308.0 76.6 69.6 69.0 71.7
312.0 77.3 69.8 69.3 72.2
316.0 77.7 70.1 69.6 72.5
320.0 77.9 70.3 70.0 72.7
324.0 78.2 70.5 70.3 73.0
328.0 78.7 70.6 70.8 73.4
332.0 78.8 70.9 71.1 73.6
336.0 79.2 71.0 71.5 73.9
340.0 79.2 71.3 72.0 74.1

344.0 79.6 71.6 72.3 74.5

APPENDIX A13 (con’t)
348.0 79.8
352.0 79.8
356.0 80.0
360.0 79.8

72.0
72.3
72.7
73.0

109

72.6
73.2
73.6

75.1
75.4
75.6

110

2:";me A14. Average temperature of corn oil heated in CPET tray for seven
nutea.

 

Time, 8 Temperature, °C
Trial 1 Trial 2 Trial 3 Average

0.0 23.1 22.5 23.1 22.9
4.0 23.5 23.2 23.8 23.5

8.0 24.7 24.3 24.8 24.6
12.0 26.1 25.6 25.7 25.8
16.0 27.3 26.9 26.6 26.9
20.0 28.4 28.0 27 .4 27.9
24.0 29.3 29.1 28.2 28.9
28.0 30.3 30.1 29.1 29.8
32.0 31.1 31.3 30.0 30.8
36.0 32.0 32.1 30.7 31.6
40.0 32.9 33.0 31.5 32.5
44.0 33.7 33.8 32.4 33.3
48.0 34.5 34.7 33.3 34.1
52.0 35.4 35.7 34.0 35.0
56.0 36.2 36.4 34.9 35.8
60.0 37.0 37.4 35.7 36.7
64.0 37.7 38.3 36.6 37.5
68.0 38.4 39.2 37.4 38.3
72.0 39.1 39.9 38.3 39.1
76.0 39.8 40.7 39.1 39.8
80.0 40.1 41.4 39.9 40.5
84.0 40.7 42.1 40.8 41.2
88.0 41.2 42.8 41.4 41.8
92.0 41.5 43.5 42.0 42.3
96.0 42 1 44.2 42.7 43.0
100.0 42.3 44.7 43.4 43.4
104.0 42.7 45.3 43.9 43.9
108.0 43.1 45.9 44.7 44.5
112.0 43.5 46.6 45.1 45.0
116.0 44.0 47.2 45.7 45.6
120.0 44.4 47.8 46.0 46.1
124.0 44.8 48.3 46.7 46.6
128.0 45.2 49.1 47.2 47.1
132.0 45.7 49.6 47.7 47.6
136.0 46.1 50.4 48.2 48.2
140.0 46.5 50.9 48.7 48.7
144.0 47.1 51.5 49.3 49.3
148.0 47.5 52.2 49.8 49.8
152.0 47.9 52.9 50.4 50.4
156.0 48.4 53.6 50.7 50.9
160.0 49.1 54.4 51.3 51.6

111

APPENDDI A14 (con’t)
164.0 49.6 55.2 51.8 52.2
168.0 50.2 55.9 52.3 52.8
172.0 50.8 56.7 53.0 53.5
176.0 51.4 57.3 53.6 54.1
180.0 52.0 58.3 54.2 54.8
184.0 52.7 59.1 54.7 55.5
188.0 53.4 59.6 55.4 56.1
192.0 54.0 60.5 55.7 56.7
196.0 54.5 61.3 56.3 57.3
200.0 55.3 61.9 56.9 58.0
204.0 55.8 62.6 57.4 58.6
208.0 56.5 63.3 57 9 59.2
212.0 57.0 63.9 58 5 59.8
216.0 57.6 64.7 59.0 60.4
220.0 58.1 65.3 59.5 61.0
224.0 58.7 65.9 60.0 61.5
228.0 59.2 66.5 60.6 62.1
232.0 59.8 67.1 61.1 62.6
236.0 60.2 67 .8 61.7 63.2
240.0 60.7 68.3 62.1 63.7
244.0 61.2 68.9 62.5 64.2
248.0 61.7 69.7 63.1 64.8
252.0 62.4 70.2 63.8 65.5
256.0 62.8 70.8 64.5 66.0
260.0 63.5 71.3 64.8 66.5
264.0 64.0 71.9 65.5 67.1
268.0 64.5 72. 66.0 67.6
272.0 65.0 72.9 66.5 68.1
276.0 65.5 73.5 67.0 68.6
280.0 66.0 74.1 67.6 69.2
284.0 66.4 74.9 68.0 69.8
288.0 67.0 75.5 68.6 70.4
292.0 67.5 76.1 69.1 70.9
- 296.0 67.7 76.6 69.7 71.3
300.0 65.5 77.5 70.2 71.0
304.0 68.7 77.8 70.6 72.4
308.0 69.1 78.3 71.1 72.8
312.0 69.7 78.8 71.6 73.4
316.0 70.2 79.3 72.0 73.8
320.0 70.6 79.7 72.4 74.2
324.0 71.0 80.2 72.9 74.7
328.0 71.3 80.8 73.6 75.2
332.0 71.7 81.1 73.8 75.5
336.0 72.1 81.4 74.5 76.0
340.0 72.3 81.6 74.9 76.3
344.0 72.5 81.9 75.3 76.6
348.0 72.8 82.0 75.6 76.8

112

APPENDIX A14 (con’t)
352.0 72.9 82.2 76.1 77.0
356.0 73.2 82.6 76.3 77.3
360.0 73.4 82.8 76.5 77.5
364.0 73.6 82.8 76.7 77.7
368.0 73.9 82.9 76.9 77.9
372.0 74.3 83.0 77.2 78.1
376.0 74.8 82.9 77.4 78.4
380.0 75.3 82.7 77.7 78.5
384.0 75.9 82.6 78.0 78.8
388.0 76.3 82.7 78.3 79.1
392.0 76.8 82.7 78.7 79.4
396.0 77.2 82.9 79.1 79.7
400.0 77.9 83.1 79.6 80.2
404.0 78.5 83.3 79.9 80.6
408.0 78.9 83.6 80.3 80.9
412.0 79.4 83.8 80.7 81.3
416.0 79.9 84.2 80.8 81 6

420.0 80.3 84.3 81.1 819

113

APPENDIX B. Temperature recorded by the four probes at four
interface locations in the susceptor material after one minute of
exposure.

 

Time, 8 Temperature, °C

Probe 1 Probe 2 Probe 3 Probe 4
0 23.9 23.0 23.5 23.5
2 24.2 24.5 24.7 24.6
4 25.5 25.6 28.6 25.0
6 29.8 26.3 33.1 26.6
8 38.5 31.2 39.8 33.9
10 51.0 38.5 47.3 49.4
12 57.4 42.0 50.6 60.3
14 63.5 45.1 55.0 67.7
16 67.7 47.5 61.5 73.6
18 71.6 50.8 67.8 81.1
20 74.5 55.7 74.1 90.9
22 74.5 62.1 82.6 103.4
24 73.6 65.8 88.1 106.8
26 76.8 69.4 93.5 106.2
28 80.5 73.3 95.2 107.9
30 82.9 77.3 99.6 110.8
32 86.3 81.9 102.0 1 15.5
34 89.4 86.4 105.8 119.3
36 92.5 92.2 108.4 122.2
38 95.3 97.4 1 12.6 124.5
40 97.9 100.6 115.0 127.2
42 100.4 103.3 118.3 130.0
44 103.0 107 .0 122.1 132.9
46 105.0 1 10.7 125.5 135.0
48 107.1 115.1 127.8 136.8
50 109.2 119.5 130.0 138.4
52 1 1 1.5 124.3 132.2 140.4
54 113.7 128.5 134.6 142.4
56 115.2 133.2 136.9 144.3
58 115.6 134.9 138.0 146.5
60 115.2 135 .8 139.6 148.4

 

114

APPENDIX C. Sample calculation of concentration of DMT, DET, and BHET in
corn oil extracts from susceptor material.

The following is a sample calculation of the concentration of DET in corn oil
extract after 1 minute exposure in the microwave oven. The calibration factor (CF) of
DET is 9.36 x 10‘12 g/units and average area response of DET at 1.0 minute is 1473 units.
The diameter of the cell was 12.2 cm, giving an exposed area equal to 1.169 dm’.
Volume of the sample injected was 10111 (0.01 ml) out of a total volume of 2.0 m1.

CFxR,me,
waA

 

Concentration (pg lg) =

9.17 x 10’11 x 1473 x 2
0.01 x 1.169

 

= 23.211321»:2

The concentration of DMT, DET, and BHET listed in Table 5 were calculated in a

similar manner.

 

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