Using α-chitin nanocrystals to improve the final properties of poly (vinyl alcohol) films with Origanum vulgare essential oil

Abstract

-In the present work, nanocomposite films based on poly(vinyl alcohol) (PVA) containing different amounts of Origanum vulgare essential oil (OEO, 0, 0.5, 1, 1.5 and 2% v/v) were reinforced with 0.5% (w/v) of alphachitin nanocrystals (α-CHNC, from shrimp and from lobster) and prepared by solvent casting. Another set of films was prepared without α –CHNC to assess the effect of the nanocrystals on the final properties of the films. The obtained nanocomposite films were homogeneous and showed better thermal stability and mechanical properties. After exposure the nanocomposite films to ultraviolet radiation, the obtained data revealed that the presence of α-CHNC into the materials has a retarding effect on their loss of mechanical properties. It was also shown that the antioxidant activity and the total phenolic content of the materials increased with the augmentation of OEO and with the antioxidant release time. Interestingly, the nanocomposite films made of chitin nanocrystals from shrimp showed better total phenolic content than the unfilled films and the nanocomposite films made of chitin nanocrystals from lobster over the first 48 h. Henceforward, this study demonstrated the potential of the nanocomposite films based on PVA, OEO and reinforced with α-CHNC for active food-packaging applications.