Sustainable zein-based bioplastic films reinforced with silver nanoparticle-embedded casein nanocomposites for active fruit packaging: characterization and functional assessment

This study aimed to synthesize silver nanoparticle-embedded casein nanocomposites (AgNP@CN) and incorporated them into zein (ZN)-derived bioplastic films to enhance their functional properties. The shape, size/dimension, morphology, surface charge, and surface chemistry of AgNP@CN were investigated. After forming AgNP@CN-functionalized ZN bioplastic films (AgNP@CN-ZN), the bioplastic films were characterized. Incorporation of AgNP@CN improved the mechanical properties, thermal stability, surface hydrophobicity, and UV resistance of ZN films. Additionally, the water vapor barrier properties of AgNP@CN-ZN bioplastic films were comparable to or superior to those of conventional plastics. In terms of food packaging, the AgNP@CN-ZN films effectively reduced weight loss and enzymatic browning in banana peels as a food model. Accordingly, the silver content in banana pulp wrapped with AgNP@CN-ZN film was 5.57 × 10 −5 mg/kg, well below the specific migration limit. Overall, the research highlights the feasibility of using nanoparticle-protein composites to reinforce the functional properties of bioplastics for sustainable packaging applications. • Silver nanoparticle-embedded casein nanocomposites (AgNP@CN) were synthesized. • Zein bioplastic films functionalized with AgNP@CN were prepared and characterized. • AgNP@CN functionalization improved mechanical strength and flexibility of zein films. • Higher AgNP@CN content of zein film has better water vapor barrier and UV resistance. • Applications of AgNP@CN-functionalized films as packaging materials were examined.