Abstract:To address the challenge of postharvest preservation of strawberries, a functional composite edible film with antioxidant and antibacterial properties was prepared. Genipin (GP) was used as a crosslinking agent to graft Nisin onto chitosan film substrates, and tea polyphenol microcapsules were incorporated into the membrane system. The influence of wall-core ratio on the embedding rate of tea polyphenol microcapsules was investigated, and the mechanical properties, water vapor permeability, antibacterial activity, antioxidant activity and strawberry preservation efficacy of the composite film were characterized. The results showed that when the wall-core ratio was 4:1, the encapsulation efficiency of tea polyphenol microcapsules reached 80.76%, and the average particle size was 2.027 μm. With the addition of 0.5% genipin, the tensile strength of the composite film increased by 45.27%, and the water vapor permeability decreased by 19.64%. With the addition of 5.0% tea microcapsules, the diameters of the inhibition zones against Staphylococcus aureus and Escherichia coli were 8.10 mm and 6.94 mm, respectively, and the antioxidant activity was 1.5 times higher than that of pure chitosan film. In the strawberry preservation experiment, the mass loss rate, pH increase and hardness decrease of the group treated by dipping in composite film solution were all significantly lower than those of the control group. The proposed composite edible film demonstrates promising application prospects in strawberry preservation.