SORPTION OF VINYLCHLORIDE BY SELECTED FOOD CONSTITUENTS

The problem of migration from a packaging material into packaged food is treated in the literature using extraction studies from polymeric materials into simulating solvents such as heptane, oil, water, 3% acetic acid, 50% ethanol, etc. (Figge, 1972). Such studies provide a good measure for predicting possible migration into foods, but do not serve as a direct measure for the relative affinity of foods or their components for the migrant (e.g. vinylchloride monomer, VCM). The approach taken in this study was to establish directly the relative affinities of the basic food constituents for vinyl‐chloride. Sorption measurements of VCM by four basic food constituents, (water, corn oil, casein and sucrose) were conducted. In addition, sorption studies were carried out with oil in water emulsions. For water, oil, oil/water emulsions and casein, it was found that the partition coefficient values (defined as the equilibrium concentration of VCM sorbed over the equilibrium concentration of VCM in headspace) were fairly constant within the sorbate (VCM) concentrations studied. At 24°C, the partition coefficient values for oil, casein and water were 23.7 × 103, 11.7 × l03 and 2.1 × 103, respectively. Sucrose did not sorb detectable amounts of VCM under the experimental conditions employed. The sorption of VCM by an oil‐in‐water emulsion, representing a multi‐component system, follows the same relationship to initial headspace concentration and temperature as do water and oil. The total amount of VCM sorbed by the emulsion, however, is not the exact arithematical sum of potential contributions of its individual components. Sorption studies showed that the chemical nature of the sorbent (i.e. food constituent), starting sorbate (i.e. VCM) concentrations and temperature are important factors affecting the extent of vinylchloride sorption. Copyright © 1979, Wiley Blackwell. All rights reserved