Preparation and Study of Antibacterial and Antioxidant Properties of a Chitosan/Rosmarinic Acid/Proanthocyanidins Composite Bio‐Food Film

ABSTRACT In response to the environmental and safety issues posed by conventional synthetic packaging materials, this study develops high‐performance natural edible biofilms using chitosan (CS) as the matrix, incorporating rosmarinic acid (RA) and proanthocyanidins (PA). The composite films were prepared via the solution casting method, and their structure was characterized using FTIR, SEM, XRD, and TGA. The pyrogallol structure of RA and the polyhydroxy flavone structure of PA synergistically enhanced free radical scavenging and metal ion chelation through their hydroxyl groups. The results demonstrate that the addition of RA and PA significantly improved the antibacterial and antioxidant properties of the films, with inhibition rates against Escherichia coli and Staphylococcus aureus exceeding 95% and DPPH (1,1‐Diphenyl‐2‐picrylhydrazyl) radical scavenging rates reaching at least 85%. Furthermore, the composite film exhibited excellent mechanical and barrier performance, achieving a tensile strength of 76.98 MPa and reducing the water vapor permeability to 0.92 × 10 −3 g m −2 h −1 Pa −1 mm. This study provides innovative strategies for the development of environmentally friendly food packaging materials.