Meaning
Chemical solvents used to mimic the aggressive extraction behaviour of oily or fatty foods are necessary for assessing the safety of plastic food packaging. These test media, classified as organic simulants, are selected based on their ability to penetrate and swell the polymer matrix similarly to food lipids. Standardized liquids include refined olive oil, synthetic triglyceride mixtures, and specific organic solvents like isooctane.
These fluids accelerate the migration of low molecular weight additives, providing a conservative measure of potential food contamination.
Testing Protocol
Regulatory compliance for food contact materials requires exposing the polymer to organic simulants under specified conditions. The temperature of the test is chosen to represent the maximum temperature the package will encounter during use. For microwaveable containers, this involves exposure to high-temperature oil simulants.
The extract is then analysed to ensure that the migration of antioxidants remains below regulatory limits.
Material Interaction
The physical impact of organic simulants on the polymer depends on the chemical structure of the resin. Amorphous polymers like polystyrene are highly susceptible to solvent swelling and structural damage when exposed to these simulants. This interaction increases the rate of additive migration by opening up the polymer matrix.
Semi-crystalline resins resist solvent penetration, resulting in lower migration rates during testing.
Analytical Calibration
Measuring extracted compounds in fatty simulants is highly complex. The simulant must be separated from the analyte before chromatography. This separation is challenging with vegetable oils.
Volatile solvents simplify the extraction.
