Rational design of antibacterial and biodegradable PCL/oxidized cassava starch/Nisin ternary films based on molecular docking

This study focuses on the rational design of biodegradable active packaging films by combining oxidized cassava starch (OCS), polycaprolactone (PCL), and Nisin via hot-pressing. Systematic characterization demonstrated that OCS incorporation reduced PCL crystallinity through hydrogen bonding, markedly altering film microstructure and functionality, and enhancing biodegradability in synergy with Nisin. Key experimental data revealed that the ternary composite films exhibited superior comprehensive performance: the soil degradation rate reached 15.98% after 72 days, a 316% increase compared to pure PCL. Regarding antimicrobial efficacy, the inhibition rate against Staphylococcus aureus reached 85.79%. Additionally, all composite films maintained low water absorption (<2%), and some formulations exhibited excellent flexibility with a peak elongation at break of 117.98%. Molecular docking further revealed that hydrogen bonds and salt bridges stabilized the structure, with the strongest binding affinity reaching −5.0 kcal/mol, influenced by the oxidation pattern of OCS. This research presents a novel, eco-friendly ternary composite film with tunable degradation and strong antibacterial activity. This work provides a strategic framework for designing next-generation carbohydrate-based active packaging and offers a practical engineering strategy to tailor bio-based films for food preservation applications.