Abstract: In order to develop a slow-release film with excellent performance, this study used polyvinyl alcohol (PVA) and chitosan (CS) as the film-forming matrix, β-cyclodextrin (β-CD) as the slow-release agent, and oregano oil (OEO) as the antibacterial and antioxidant. OEO was used as an antibacterial and antioxidant agent to prepare β-CD/CS/PVA films with different OEO additions. The effects of different OEO additions on the basic properties, physicochemical structure, antibacterial and antioxidant properties and slow-release performance of the composite films were investigated. The results showed that FTIR showed that none of the components caused changes in membrane structure; with the increase of OEO addition, the mechanical properties, thermal stability, hydrophobic properties and photo-blocking properties were improved, and the antibacterial and antioxidant abilities were significantly enhanced (P<0.05), among which the inhibition circles of CP-O2% were 10.00 mm and 10.86 mm for S. aureus and E. coli, respectively, and the scavenging rate of DPPH radicals was as high as 80.84%. The composite membranes also had good slow release performance in 95% ethanol, in which CP-O0.5% and CP-O1.5% could be continuously released in this medium for 540 min. It was concluded that when OEO was added at 2%, the composite membranes had better overall performance and more potential for research and development.

Key words: polyvinyl alcohol, chitosan, oregano oil, β-cyclodextrin, sustained release