Chitosan-based coatings and films: Mechanisms and applications in postharvest preservation of mangoes

Mangoes, a globally significant tropical fruit, suffer substantial postharvest losses due to ethylene sensitivity, chilling injury, and fungal infections. Chitosan-based coatings and films have emerged as sustainable solutions to mitigate these challenges. This review elucidates the mechanisms by which chitosan preserves mango quality, including the formation of a semi-permeable barrier to regulate gas exchange and moisture loss, direct antimicrobial activity against pathogens like Colletotrichum spp., and induction of systemic resistance through defense-related enzyme activation. Furthermore, chitosan's antioxidant properties delay oxidative senescence by scavenging reactive oxygen species. Recent advancements in composite formulations—such as blending chitosan with polysaccharides, proteins, nanoparticles, and plant-derived extracts—enhance mechanical strength, barrier properties, and bioactive performance. Despite promising laboratory results, challenges persist in scaling up production, optimizing additive concentrations to balance efficacy and phytotoxicity, and ensuring regulatory compliance. This work consolidates fragmented knowledge, providing a theoretical framework for chitosan-based preservation technologies and highlighting future directions for sustainable postharvest management of climacteric fruits.