Food aroma partition between packaging materials and fatty food simulants

By means of thermal desorption experiments, the partition equilibrium (partition coefficient, K) was analysed for six food aroma components (d-limonene, n-decane, ethyl caproate, phenylethanol, n-hexanol and hexanal) between three sealable polymer films suitable for direct food contact (ultra-low density polyethylene, ULDPE; ionomer, ION; and polyester, PET) and four fatty food simulants (ethanol 95%, EtOH: sunflower oil, Oil; n-heptane, HEP; and iso-octane, OCT). The results showed that aroma scalping is highly dependent on the fatty food simulant utilized. Polar aroma components were more sorbed into polymers in the presence of a non-polar fatty food simulant, and vice versa. K values in the presence of Oil were always between those in EtOH and in HEP or OCT. In general, PET was the packaging film which showed the lowest partition coefficient for non-polar components while ULDPE showed the lowest partition for polar aromas. The partition equilibrium of mixed d-limonene, ethyl caproate, and n-hexanol was also determined. The differences in K values between isolated aromas and mixed aromas were small. In general, the most sorbed aroma showed increased partition by mixture while the partition of the least sorbed was reduced.