food& flavors
Applications
note
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food& flavors
MonitoringVolatileCompounds in FoodContact PackagingUsingPurge and
TrapGC/MS and anRtx
®
-5MSCapillaryColumn
Introduction
Food packaging can be designed from awide variety ofmateri-
als, in a range of sizes, shapes, and colors.With the increasing
popularity of convenience foods, meals often are preparedwith-
in the packagingmaterials. Packagesmight be placed in an
oven, amicrowave, orwithin a pot of boilingwater. For
microwavable packaging, foodmanufacturers prefer to use
cheap, safe, and, to some extent, recyclablematerials.
1
Microwave susceptor systems can be used to heat foodsmore
rapidly, aswell as to crisp and brown the foods they contact.
Susceptors aremade by laminatingmetallized polyester to paper-
board. For dual-ovenable applications, ovenable paperboard and
CPET (crystalline polyethylene terephthalate) can be used.
For all packagingmaterials, there is the potential to generate
undesirable volatile compoundswhen used at elevated tempera-
tures. Inmany instances, these compounds canmigrate into or
out of packagingmaterials.When flavor compoundsmigrate
out of a food or beverage into the packaging, scalping occurs.
This can result in a loss of flavor or a change to the flavor pro-
file. Ofmore concern from a food safety perspective are com-
pounds that have the potential tomigrate out of the packaging
material into the food product.
TheUSFood&DrugAdministration (FDA) has stated,
“Anyonemanufacturing food contact articles for use in the
home or in food service establishments shouldmake sure that
nothing from the articles imparts flavor, color, odor, toxicity, or
other undesirable characteristics to food, thereby rendering the
food adulterated.”
2
In order to test the safety of food contact
materials, packaging should be tested under simulated use con-
ditions. Purge and trap gas chromatography/mass spectrometry
(GC/MS) is a powerful tool formonitoring the volatile com-
pounds that are generated during heating of packagingmateri-
als. This analysis technique can be applied to awide range of
packagingmaterials that are heated during food preparation.
Indirect food additives are defined as substances that are used
in the processing, packaging, holding, and/or transporting of
food, have no functional effect on the food, but whichmight
become a component of the food.
1
Plastic packaging in general
ismade of non-volatile, highmolecular weight polymers, but
volatile compounds often are added to improve the functional
properties of the polymers. Such volatile compounds include
plasticizers, antioxidants, UVblockers, and lubricants. The
packaging inks and dyes used to create the label graphics can
contain residual solvents, whichmay be toxic at certain concen-
trations. In addition, thermal breakdown of a polymermight
occur in the inner ply of a boil-in bag or oven bag, thereby
forming volatile species. Compounds such as benzene, styrene,
and tetrahydrofuran (THF) have been shown to cause adverse
affects on humans, and food contact materials need to be tested
to ensure these volatiles are not present at significant levels.
In addition to the safety concerns, volatile compoundsmigrat-
ing into foodmaterials can change the flavor profile of the food
product. For example, polystyrene is used to packagemany
aqueous-based, fatty or dry foods. Trace levels of styrene pres-
ent in the polystyrene can impart a “plastic” taste to the food
product.
In 21CFR 170.39, theUSFDAoutlines the data needed to
request an exemption from regulation as a food additive.
Information needed includes the use conditions, time/tempera-
ture, food type, andwhether thematerial is used once ormulti-
ple times. Other required information includes a detailed
description of the analytical method and themethod validation
data, including the detection limit.
Figure 1
1. isopropanol
2. methylene chloride
3. 2-methyl-1-propanol
4. tetrahydrofuran
5. benzene
6. toluene
7. hexanal
8. furfural
9. 4-heptanone (IS)
10. butyl ether
11. styrene
12. dodecane
The Rtx
®
-5MS column exhibits good peak shape and high
sensitivity for 12 volatile compounds that may
be present in food packaging.
1
2
9
3
4
5
6 7 8 10
11
12
2 4 6 8 10 12 14 16 18 20
GC_FF00457
See Table I, back page,
for analysis conditions.
