Sorption of flavour compounds in aqueous solution into polyethylene film

Sorption of flavour compounds by the polyethylene (PE) liner of laminated pouches (PET/Al/PE) containing a flavour solution has been studied. The solution contained 43 volatile compounds (each 2 μl litre⁻¹) in sugar ester solution (3 g litre⁻¹). The distribution ratios of the flavour compounds for sorption into various PE liners increased with carbon chain length of the flavour compounds from 0.01 to 0.1 for alcohols, from 0.03 to 1.23 for aldehydes, from 0.02 to 5.77 for aliphatic esters and from 0.11 to 11.6 for benzoates. In each series (all straight‐chain compounds) the distribution ratios increased about threefold for each methylene group, but in the compounds composed of 11 or more carbon atoms the increment was less or negative. The distribution ratio for a given PE film was proportional to the film thickness. The distribution ratios increased with decreasing crystallinity of the PE film and the results for the films of different crystallinities suggested the existence of an impermeable boundary region surrounding the crystalline material amounting to about 20% of its volume.