Abstract In order to explore the effects of thymol on the antimicrobial activity, structure, physical properties and fresh-keeping application of starch/PBAT composite films, different contents of thymol (0, 1%, 3% and 5%) were used to prepare antimicrobial composite films by extrusion blow molding. The results indicated that tourier transform infrared spectroscopy showed there was intermolecular hydrogen bonding force among starch/PBAT and thymol. The inhibition effect on Botrytis cinerea and the preservation effect of cherry tomato of the composite film were significantly improved, the hardness and nutritional characteristics of cherry tomato were maintained, and the fruit decay rate was reduced. The addition of thymol increased the water vapor permeability of the starch based composite films, but reduced the interaction between the composite film and water. Although thymol reduced the mechanical properties of the composite film, high concentration of thymol further improved the mechanical properties. In conclusion, the high concentration of thymol improved the comprehensive properties of starch composite film, and proved the application prospect of the film as active food packaging material.

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.