PLA‐Derived High‐Barrier Slow‐Release Antibacterial Film: Industrial‐Scale Preparation and Enhanced Preservation of Salmon

This study developed an industrially scalable, fully bio-based multilayer film for sustainable packaging of high-fat aquatic products. The film combines high barrier properties with long-acting antimicrobial function through a tailored structure: Outer polylactic acid (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) and intermediate polyvinyl alcohol (PVA) barrier layers, and an inner PLA/PBAT/thermoplastic starch (TPS) blend layer serving as a reservoir. To enable sustained release, a β-cyclodextrin-carvacrol inclusion complex (β-CD@CAR), prepared by saturated aqueous solution, was incorporated into this reservoir layer. The resulting film showed excellent barrier performance (OTR: 298.9 ± 6.1 cm3/m2·24h·0.1 MPa; WVTR: 146.21 ± 41.45 g/m2·24 h) and robust mechanical properties (tensile strength: 27.32 ± 5.12 MPa; elongation at break: 72.15 ± 11.22%). The β-CD@CAR complex provided controlled CAR release, imparting strong antibacterial activity (reductions of 1.88 and 2.01 log CFU/g against Staphylococcus aureus S. aureus and Escherichia coli E. coli, respectively). When applied to salmon preservation, the film effectively delayed microbial growth, pH increase, color deterioration, quality loss, and protein oxidation, extending shelf life by at least four days. This work demonstrates a scalable strategy for active packaging by integrating a multilayer barrier with a cyclodextrin-mediated release system, showing significant industrial potential for preserving perishable, high-fat foods. Notably, the film was fabricated via industrially viable melt-extrusion and thermal lamination. This scalable approach, combined with the tailored multilayer architecture, represents a significant advance towards practical active packaging.