Transformative nanoantioxidant chitosan films: High-performance active packaging with minimal cytotoxicity

This study developed a nanoantioxidant-based active food packaging film with antibacterial activity, low cytotoxicity, and potential for food preservation. Ag-doped ZnO nanoparticles (ZnO.Ag NPs) were synthesized with antioxidant and UV-shielding properties and loaded with catechin (Cat) to enhance biological activity. These nanoantioxidants were incorporated into chitosan/poly(vinyl alcohol) (CS/PVA) films (CP.(ZAC)) at varying concentrations. Adding ZnO.Ag@Cat reduced the water contact angle (89° to 78°) and water vapor permeability (121 × 10^-4 to 99 × 10^-4 g.Pa^-1.day^-1.m^-1). The films exhibited nearly 100 % antibacterial efficacy against Staphylococcus aureus and Escherichia coli. Molecular docking revealed that catechin inhibited bacterial virulence factors, including SarA and CRP proteins. CP.(ZAC)₉ extended strawberry shelf life at 4 °C to 12 days while maintaining quality indices such as weight loss, total soluble solids (TSS), pH, and electrical resistance. The antioxidant properties of CP.(ZAC)₉ mitigated oxidative stress, reducing H₂O₂ accumulation in strawberries. These findings demonstrate the potential of nanoantioxidant-based films to enhance shelf life and quality, offering a sustainable alternative for food preservation.