STUDY OF AROMA SCALPING THROUGH THERMOSEALABLE POLYMERS USED IN FOOD-PACKAGING BY INVERSE GAS-CHROMATOGRAPHY

Scalping of aroma components in polymers used for food packaging was d etermined by solubility experiments. Aromas were selected from differe nt families. esters, alcohols, hydrocarbons and ketones. Polymers were a linear low density polyethylene (LLDPE), an ionomer and a new therm osealable polyester (PET). Polymers were selected from thermosealable materials because of their resistance to fats and oils. Sorption isoth erms (low sorbate activity range) for every system aroma (vapour)/poly mer were determined by inverse gas chromatography. Isotherms were foun d to be linear. Hence, solubility coefficients (S) as defined by Henry 's law were calculated from the isotherm slopes. According to S values , PET appears to be the best choice to minimize aroma scalping by sorp tion in the packaging inner layer, Ionomers improve the barrier to aro ma when compared with LLDPE except for polar sorbates. Sorption of aro ma components was shown to be selective, e.g. limonene was preferentia lly sorbed in LLDPE. The value of S for the limonene/LLDPE system was 2.5 times the value of S for ethyl caproate/LLDPE. This selectivity ma y lead to an imbalance in the flavour and may be more important than t he prevention of overall scalping.