Interaction of fat‐ containing food with plastics packaging

Abstract

AbstractPackagings for fatty food should protect against light, oxygen, microorganisms, and loss of water vapor and flavor substances. Low off‐taste and adequate mechanical stability is required. Pigmented plastics fulfill most of these requirements. Two main effects caused by the interaction of fatty food components with plastic packaging materials are described: stress cracking and migration. A method for characterizing fatty foodstuffs was developed to distinguish between foodstuffs containing free fat available on the surface and those actually having an aqueous surface. The basic types of migration behavior are shown by typical migration curves of an antioxidant from rigid PVC and from HD‐PE into test fat. In model experiments, the swelling of the HD‐PE as well as the migration of the antioxidant was determined quantitatively as a function of time by means of radiotracer techniques. Based on these results and Fick’s diffusion equations, a theory was developed with which it is possible to describe the migration behavior of antioxidants from polyolefins and PVC quite precisely. It was also possible to solve some problems with HI‐PS. This mathematical model permits calculation of the migration at constant temperature as a function of time and concentration of the antioxidant in the polymer. As there is a definite mathematical relationship between the concentration of an additive in the polymer and the migration into test food or actual food, it is recommended that regulations for plastic food packaging are based on compositional limits, rather than migration limits, because of definite advantages in compliance and control.