Abstract: Edible composite films were prepared from chitosan (CS) and γ-polyglutamic acid (γ-PGA) as film-forming materials with added curcumin (Cur). The thickness, water solubility, transparency and surface structure of the films were studied, and the antibacterial effect against bacteria on the surface of bacon and sausage was evaluated. The results showed that addition of γ-PGA reduced the film thickness and increased water solubility. Under scanning electron microscopy, the CS/Cur/γ-PGA film showed a compact surface. The Fourier transform infrared (FTIR) spectra of the pure and composite films indicated that there was an interaction among CS, Cur and γ-PGA in the mixed solution. The CS/Cur/γ-PGA composite film was applied to the surface coating of bacon and sausage, and it was found that the sensory quality of the samples treated with it was superior to that of commercially available wrap film packaging after storage under the condition of 28 ℃ and 50% relative humidity for 3 days. The total number of colonies in the composite film group was 1 (lg(CFU/g)) lower than the commercially available wrap film packaging group. The edible composite film has the potential to play a positive role in food preservation.

Key words: edible film, chitosan, γ-polyglutamic acid, curcumin