Active chitosan- poly (vinyl alcohol) film reinforced with zinc oxide nanoparticles for food packaging applications

Active packaging represents an innovative alternative to improve the quality of food and extend the shelf life of the product. The main aim of this research is to develop antibacterial films based on chitosan (Cs), polyvinyl alcohol (PVA), and zinc oxide nanoparticles (ZnONps) to find a solution of food deterioration due to the presence of pathogenic microorganisms. ZnONps were synthesized by green chemistry using the leaves extract of Petroselinum crispum. The films were fabricated with 0; 0.5; and 1% w/v of ZnONps using different proportions of Cs: PVA by the casting method. The mechanical, physicochemical, antimicrobial, and antifungal properties were assessed. Moreover, the influence of the Cs/PVA/ZnONps films in the conservation of the Isabella grape was analyzed (pH, titratable acidity, weight loss, total soluble solids, and decay rate) and it was compared to commercial coating and uncoated grapes. Results showed the increase in the content of PVA improved the mechanical properties and increased the water absorption. Besides, Young’s Module, and tensile strength of the films improved with ZnO nanoparticles addition. The antimicrobial activity of the nanocomposite films against Escherichia Coli was demonstrated. Finally, it was corroborated the nanocomposite films preserve the quality and extend the shelf life of Isabella grapes 6 days more than the commercial coating affirming their use in food packaging. To the best of our knowledge, no previous work related with the development of films based on Cs/PVA reinforced with ZnONPs has tested its application as fruits packaging, determining its effect on the ripening process through physic-chemical assays. Graphical Abstract