Abstract: Proper packaging of foods is of particular importance for inhibiting the growth and reproduction of harmful microorganisms in foods during storage, delaying the quality deterioration and extending the shelf life. Chitosan-coated antimicrobial polyethylene (PE) bilayer films incorporated with hops extract were prepared in this study to investigate the effects of different concentrations of hops extract on the surface structure, physical properties and antibacterial activity of the films. Furthermore, the release behavior of hops extract from the films was investigated in simulated food systems (ethanol solutions at 10%, 50%, and 95%, V/V) at different temperatures (4, 25 and 35 ℃). The results showed that the addition of hops extract especially at 0.2 g/100 mL increased the water resistance and UV barrier capacity of the film and imparted good antioxidant and antimicrobial activity to it. Under the same conditions, the release percentage of hops extract increased with increasing its concentration, and the release amount similarly increased with increasing temperature and ethanol concentration, which indicates that the chitosan-coated antibacterial PE bilayer films could be used for the packaging of high-fat foods. Moreover, the antibacterial films not only overcome the poor water resistance of single-layer edible films, but also had antibacterial effects while PE packaging films do not have.

Key words: hops extract; chitosan; polyethylene; release; bilayer film