Dynamic Approach to the Sorption of Flavors into a Food Packaging Film

A new analytical method for determining the diffusion, permeation and solubility coefficients of flavors into food packaging materials has been established. The proposed method for gaseous and aqueous samples is based on the monitoring of the flavors that have passed through a film by a flame ionization detector. One can thus predict the dynamic sorption behavior of flavors in food packaging materials under a low vapor pressure. The factors which affect the sorption behavior were elucidated by using of the present method. In order to improve the sorption property of packaging materials, modifications of the packaging materials by electron-beam irradiation and by hydrolysis for ethylene vinyl acetate copolymer (EVA) and polyethylene films were studied. In both modified films, the sorption depression was observed for volatile compounds with a low solubility parameter (SP) value; this effect resulted from a restriction of the chain mobility by mild crosslinking and a lowering of the affinity by surface polarization for irradiated and hydrolyzed films, respectively. Furthermore, by using the proposed thermodynamic affinity concept, represented as the twodimensional distance (δC) between two SP values of film and flavor, packaging materials with high flavor preservation against sorption can be designed.