Preparation and properties of chitosan/zein-perilla essential oil composite film: its structure, physicochemical characterization, and antioxidant properties

This study used chitosan and zein as film-forming matrices and added perilla essential oil (PEsO) to prepare a new type of fresh-keeping film. The morphology, structure and properties of the composite film were analyzed through scanning electron microscopy (SEM), infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), hydrophilicity/hydrophobicity and antioxidant tests. Compared with chitosan/zein film, films loaded with PEsO exhibited a significant increase in barrier capacity, thermal stability and antioxidant ability. SEM analysis showed that after the addition of PEsO, micropores and particles were formed on the film surface, which affected the mechanical properties of the film and decreased the tensile strength and elongation at break of the film. FTIR indicated that there are inter-molecular interactions between PEsO, chitosan, and zein. Thermo- gravimetric analysis showed that PEsO delayed the thermal decomposition of the film and improved its thermal stability. Overall, the addition of PEsO enabled to improve the optical properties, barrier properties, thermal stability and antioxidant properties of the chitosan/zein film, and the composite film could be a good candidate for food packaging material especially applied for high-fat and easily oxidized foods.