Chitosan/indole-3-acetic acid/silver nanoparticle composite films: Preparation, characterization and efficacy in inhibiting postharvest potato dry rot.

This study aimed to prepare and characterize a chitosan (CS)-based composite film incorporating indole-3-acetic acid (IAA) and silver nanoparticles (AgNPs) via a solution casting method, and to evaluate its efficacy in controlling Fusarium oxysporum-induced dry rot in postharvest potatoes. Microstructural analysis revealed uniformly dispersed AgNPs and a compact network, with FTIR and XRD confirming that hydrogen bonding dominates CS and IAA interactions while coordination interactions govern CS and AgNP associations. This compact network significantly enhanced tensile strength (40.09% increase) and barrier properties (12.57% reduction in WVP). The film also exhibited improved hydrophobicity (WCA = 75.09°), thermal stability, and antioxidant activity. Notably, it showed significant inhibitory effects against F. oxysporum (30.04 mm inhibition zone), reducing decay rate to 6.17% (70.56% reduction) in storage trials. These findings suggest that the CS/IAA/AgNPs film represents an effective approach for managing postharvest potato dry rot, demonstrating great potential for practical application.