Preparation of acrolein/resveratrol-grafted chitosan-sodium alginate bilayer films and their antibacterial and antioxidant activities

Active packaging tends to maintain the quality of fruits and effectively controls spoilage. In this study, active bilayer thin films were prepared using chitosan, sodium alginate, and resveratrol as the raw materials. Acrolein was used to cross-link chitosan with resveratrol, and the residual acrolein was removed using cysteine. Acrolein increased the loading capacity of resveratrol on chitosan by 142.53% and 71.35% compared with the crosslinking agents cinnamaldehyde and glutaraldehyde, respectively. The covalent binding of resveratrol-acrolein-chitosan significantly and remarkably improved the mechanical properties, light resistance, antibacterial and antioxidant capacities of the bilayer films. Fruit preservation confirmed that the bilayer thin film could effectively prevent browning of fresh-cut apples. The film properties indicate that this newly designed bilayer film can serve as an effective and competitive packaging material to solve the problem of fresh-fruit preservation.