Abstract:Chitosan and gelatin come from natural sources and have good film-forming properties, but both have poor bacteriostatic performance, which limits their application in food packaging. In order to
enhance antimicrobial activity of the film, nano-zinc oxide was incorporated in gelatin/chitosan composite film. In this study, chitosan and gelatin were used as film-forming materials and nano-zinc oxide was added as antibacterial material, and the composite film was prepared by blending method. The effects of nano-zinc oxide content on the structure ,mechanical properties and antibacterial properties of chitosan/gelatin/nano-zinc oxide composite films were investigated. The results showed that the introduction of nano-zinc oxide effectively improved the mechanical properties,water vapor permeability ,thermal stabilily and antibacterial properties of the composite film. When the content of nano-zinc oxide in the composite film is 0.5% , the antibacterial performance of the composite film was the best, with the water solubil-ity of 17.3% , the water absorption rate of 100.0% , the tensile strength of 5.5 MPa, the elongation at break of 8.0% , the water vapor transmittance of 94.72 g·m 2 . hˉ', the water vapor permcability of 2.44 x10-" g?cm'·s'·Pa', and the diameter of the zone of inhibition of Staphylococcus aureus of(37.8±0.1) mm and Escherichia coli of (25.7±0.1) mm. These findings indicate that chitosan/gelatin/nano-zinc oxide composite films have great potential to be developed as biodegradable alternative for postharvest packaging of fresh fruits and vegetables.