Abstract In order to investigate the controlled release and antifungal effect of thyme essential oil on peach fruit, the four polysaccharides such as xanthan gum, gum tragacanth, arabic gum and pullulan were used to construct the essential oil-chitosan based composite film. The physical and chemical properties of composite film and its inhibition effect on Monilinia fructicola of peach fruit in vitro and in vivo were evaluated. The results showed that thyme essential oil contained some antifungal compounds such as 2-methoxy-3- (2-propenyl)-phenol, D-limonene and thymol. The addition of four polysaccharides decreased the tensile strength and elongation at break of composite film, and caused obvious fluctuation in the peak at 3263, 2884, 1552 and 1025 cm-1. Particularly, the strong interaction was found between chitosan and arabic gum which improved the antifungal effect of thyme essential oil in vitro. Moreover, the chitosan composite film combined with arabic gum exhibited the best inhibition effect on Monilinia fructicola of peach fruit in vivo regardless of the coating of film solution or film fumigation method. The work showed that chitosan-arabic gum composite film would be a potential application for improving the antifungal effect of essential oil on the preservation of peach fruit.

Abstract In order to optimize the performance of chitosan-tea polyphenols composite films, effects of glycerol and Tween on the antioxidative activities and physical performance of chitosan composite films were evaluated. The results indicated that both flexibility and water vapour permeability of chitosan/tea polyphenols films were improved with the addition of glycerol, meanwhile the solubility and swelling degree decreased. Moreover, the release time of antioxidants from films was delayed with the addition of glycerol. The presence of Tween 20 had no significant effect on the tensile strength of films, but changed the DPPH radical scavenging activity depending on the blend ratio of glycerol and Tween. DSC, FTIR and X-ray analysis showed strong interaction among chitosan, tea polyphenols, glycerol and Tween. The optimum ratio was 0.5% tea polyphenols, 1.2% glycerol and 0.1% Tween. This study provided a reference that an optimized chitosan/tea polyphenols composite film could be obtained by the regulation of glycerol and Tween.