Hydroxytyrosol as active ingredient in poly(vinyl alcohol) films for food packaging applications

Hydroxytyrosol (HTyr), a biophenol found in extra-virgin olive oil or olive oil by-products, well known for its strong antioxidant activity, was used as active ingredient for poly(vinyl alcohol) (PVA) matrix to develop film formulations by solvent casting process. The effect of HTyr on the morphological, thermal stability, optical, mechanical and release properties of PVA were investigated, while water absorption capacity, migration with food stimulants, water vapor permeability and antioxidant properties were tested taking into account the final application as food packaging systems. Morphological investigations evidenced homogeneity of all PVA/HTyr films, while the presence of HTyr clearly accounted for an increase of the crystallinity degree of the polymer matrix and also for providing antioxidant activity of the final films. The successful development of novel, environmentally friendly, safe active food packaging materials as an alternative to that which is petroleum based represents solid ground for product improvement and future testing on food.