Active Chitosan/Gelatin Composite Films Incorporated with Biosynthesized AgNP-Loaded Nanoliposomes: Characteristics, Bioactivities, Release Rate and Application for Shelf-Life Extension of Mussel Meat

Functional biopolymer-based packaging systems incorporating nanostructured active components have gained increasing attention for improving food stability and extending shelf-life. Chitosan/gelatin (CS/GE) composite films containing biosynthesized silver nanoparticle-loaded nanoliposomes (AgNP-NLs) at 0, 1, 3, and 5% (w/w, polymer basis) were developed. Their structural, physicochemical, mechanical, barrier, antioxidant, antimicrobial, and release properties were examined. Scanning electron microscopy images showed a continuous matrix with dispersed nanoliposomal structures, while Fourier-transform infrared spectroscopy spectra indicated the interactions between AgNP-NLs and the CS/GE network without major disruption of characteristic functional groups. Increasing AgNP-NLs concentration markedly improved ultraviolet (UV) protection, with UV-B blocking reaching 99.30% in the 5% film, and enhanced antioxidant and antimicrobial activities. The 5% film exhibited temperature-dependent Ag+ release. A slower and more sustained release was achieved at 4 °C than at 25 °C. When applied to wrap mussel meat, the 5% film effectively retarded lipid oxidation and microbial growth, as evidenced by lower peroxide value, thiobarbituric acid reactive substances, total viable, and psychrophilic bacterial counts. Eicosapentaenoic acid content was retained, and the formation of oxidation-related volatiles was reduced. Overall, AgNP-NLs incorporation improved CS/GE film functionality and extended refrigerated mussel shelf-life to 12 days compared with 6 days for the control.