DETERMINATION OF THE OVERALL MIGRATION FROM SILICONE ELASTOMERS INTO SIMULANTS AND FOODSTUFFS USING ~1H-NMR TECHNIQUES

摘要

Silicone baking moulds among other silicone products for food contact applications have had a market share between 23 and 46 % within the last few years and are therefore of relevant economic importance. Their migration properties are regulated within the Council of Europe's Resolution AP (2004) 5 on silicones used for food contact applications and German BfR Recommendation XV on silicone articles. To examine the inertness and migration properties of common silicon moulds during preparation of different foodstuffs a new analytical approach based on ~1H-NMR spectroscopy was developed and used to analyse household as well as a commercial usage of silicone moulds. In all cases mainly cyclic and sometimes additionally linear silanol terminated dimethyl siloxanes were found to be the substances transferred into foodstuffs. Oligomers up to 50 [Si(CH3)2-0]-units have been identified. Migration mainly depends on the type of food (fat content, consistency) and contact temperature. For stirred cakes, pizza and creme bailee silicone moulds may usually meet the overall migration limits of the Council of Europe's Resolution AP (2004) 5 for foodstuffs of 60 mg/kg. However, food with a high content of free available fat as for instance a meat loaf may exceed the limit. Furthermore migration rises with time and temperature of the preparation conditions but slowly decreases during repeated usage. No significant formation of potentially migrating substances could be observed during repeated heating or long-term usage. Incorporation of fat from the foodstuff into the elastomer accounts to about 1 % (w/w) and may lead to sensory spoiling of the material.