Application of Ag/Tannic acid-Fe^III nanocomposite as multifunctional bacteriostatic to enhance the performance of chitosan/gelatin/polyvinyl alcohol complex films

As the demand for food quality and safety continues to rise, antimicrobial active packaging materials with good mechanical and barrier properties have received urgent attention from the food industry. In this study, three types of Ag/tannic acid-Fe-III ion nanocomposites (TFA) were synthesized using an in-situ method and incorporated into a chitosan/gelatin/polyvinyl alcohol complex film (CF) to produce multifunctional and highly crosslinked active films. The impact of TFA prepared through three different methods on the microstructure and functional properties of the CF were investigated. The structure of the TFA-loaded films was investigated to confirm the strong intermolecular interactions between the polymers and TFA. The TFA established multidimensional physical interactions and cross-linked the polymers, thereby enhancing the mechanical properties of the CF and providing excellent antioxidant activity and photothermal effects. Under 808 nm near-infrared laser irradiation, the TFA-loaded films displayed potent antibacterial performance against both S. aureus and E. coli bacteria. This study demonstrated that the nanocomposite prepared via ascorbic acid reduction (TFAV) given the highest comprehensive performance rating to the film. It can be utilized not only for conventional food packaging but also as a continuous sterilization strategy for meat products storage due to its photothermal antibacterial functionality.