Effect of hydroxytyrosol methyl carbonate on the thermal,migration and antioxidant properties of PVA-based films for active food packaging

Hydroxytyrosol methyl carbonate (HTyr-MC), a synthetic non-cytotoxic hydroxytyrosol-derived compound showing excellent antioxidant capacity, was obtained in high yield and purity by an ecofriendly procedure and used as active ingredient for poly(vinyl alcohol) (PVA) matrix. Novel PVA/HTyr-MC binary films were developed by solvent casting in water adding 2%, 5% and 10% by weight of HTyr-MC to PVA. Morphological, thermal and optical properties, water absorption capacity,migration to foodsimulant andantioxidant characteristics ofPVA/HTyr-MCfilmswere finely investigatedin viewof their potential application as active food packagingmaterials. The morphological and transparency studies underlined that HTyr-MCwas homogeneously dispersed in the PVAmatrix and it is able to act as a nucleation agent, influencing the diffusion processes of the water through the polymer chain without negatively affecting the release of the active ingredient. The overall migration levels for all studied formulationswere lower than the migration limits permitted by the current legislation for food contactmaterials while the data of antioxidant assays demonstrated a good antioxidant activity induced by HTyr-MC presence also at the lowest concentration. These novel films represent a valid and sustainable alternative to non-ecofriendly-basedmaterials.