Time-temperature study of the kinetics of migration of DPBD from plastic into chocolate, chocolate spread and margarine

Migration of low molecular weight substances into foodstuffs is a subject of increasing interest and an important aspect of food packaging because of the possible hazardous effects on human health. The migration of a model substance (diphenylbutadiene) from low-density polyethylene (LDPE) was studied in foodstuffs with high fat contents: chocolate, chocolate spread and margarines (containing 61% and 80% fat). A simplifying mathematical model based on Fick's diffusion equation for mass transport processes from plastics was used to derive effective diffusion coefficients which take also kinetic effects in the foods into account and to determine partition coefficients between plastic and food. With this model migration levels obtainable under other storage conditions can be predicted. The effective diffusion coefficients for both margarines stored at 5 degrees C (3.0-4.2 x 10(-10) cm(2) s(-1)) and at 25 degrees C (3.7-5.1 x 10(-9) cm(2) s(-1)) were similar to each other, lower than for chocolate spread stored at 5 degrees C ( 9.1 x 10(-10) cm(2) s(-1)) and higher than the diffusion coefficient for chocolate stored at 25 degrees C (2.9 x 10(-10) cm(2) s(-1)). Good agreement was found between the experimental and the estimated data, allowing validation of this model for predicting diffusion processes in foodstuffs with high fat contents.