Diaporthein B/ZnO/chitosan biodegradable film for postharvest preservation of apples: Characterization and application

Apple ring rot, caused by Botryosphaeria dothidea , is a major postharvest disease that reduces the shelf life and quality of apples. In this study, a biodegradable composite packaging film was developed by incorporating diaporthein B (DTB), a marine-derived antifungal compound, into a chitosan (CS) matrix reinforced with zinc oxide nanoparticles (ZnO). This strategy aimed to enhance the bioavailability and applicability of DTB for postharvest disease control. The resulting DTB/ZnO/CS film exhibited synergistic antifungal activity and significantly suppressed lesion expansion caused by B. dothidea on infected apples, with an inhibition rate of 65.5 % after 4 days of incubation. Moreover, it contributed to maintaining fruit quality by preserving physicochemical quality, delaying senescence, and mitigating oxidative stress during storage. Biodegradability assays confirmed the film’s rapid degradation in natural soil, highlighting its eco-friendly properties. Subacute toxicity evaluations indicated no adverse effects, supporting its biosafety for potential food-contact applications. Overall, the DTB/ZnO/CS film represents a sustainable and practical strategy for controlling apple ring rot and other postharvest fungal diseases, while contributing to food safety and sustainability.