Interactions between aroma and edible films. 1. Permeability Of methylcellulose and low-density polyethylene films to methyl ketones

This work contributes to the study of aroma transfers through edible and plastic packaging films. Permeability, sorption, and diffusivity of three methyl ketones (2-heptanone, 2-octanone, and 2-nonanone) in and through low-density polyethylene and methylcellulose-based edible films have been determined. Permeability was measured using a dynamic method coupled with a gas chromatograph. The methyl ketone permeability of polyethylene films mainly depends on diffusivity of the penetrant in the polymer. In the case of 2-heptanone, a saturation of the polymer network is observed at high vapor concentrations. The formation of clusters could take place when concentrations are higher in the vapor phase. Physicochemical interactions between aroma compounds and components of the methylcellulose-based film induce structural changes such as plasticization. Therefore, the diffusion step depends on the aroma concentration differential, and permeability is essentially driven by the sorption.