Characterization of olive leaf extract polyphenols loaded by supercritical solvent impregnation into PET/PP food packaging films

An olive leaf extract (OLE) obtained by enhanced solvent extraction (ESE) with high antioxidant was used as the active substance in supercritical solvent impregnation (SSI) of PET/PP films. The extract was characterised by UPLC-QTOF-MS and it was then compared with the profile of the impregnated polyphenols for different operational conditions, namely pressure (100, 200, 300 and 400 bar) and time (5 min and 1, 2, and 22 h), in order to evaluate the possible selective impregnation. Oleuropein and luteolin-7-glucoside were the main phenolic antioxidants in both the extracts and the impregnated matrices. 400 bar and 1 h were stablished as the best impregnation conditions due to the higher concentration and wider variety of OLE compounds observed in the matrix. After study the migration of compounds into food simulants, the effectiveness of the impregnated film against lipid oxidation was evaluated during the storage of sunflower seeds.