Biopolymer-Based Nanocomposite Edible Coatings for Postharvest Preservation of Horticultural Crops: Mechanisms, Functional Additives, and Safety Perspectives

Postharvest losses of horticultural crops represent a significant global challenge, impacting food security, economic stability, and environmental sustainability. Traditional preservation methods cannot maintain the quality and extend the shelf life of these highly perishable commodities. In response, biopolymer-based nanocomposite edible coatings have emerged as a promising, eco-friendly alternative. Existing reviews typically address barrier mechanisms, functional additives, or safety in isolation and rarely integrate nanomaterial migration and regulatory considerations with coating design and application. This gap limits the translation of laboratory findings into safe, commercially viable coatings. This review therefore provides an integrated, mechanism-to-safety synthesis of biopolymer nanocomposite edible coating. This review examines the physiological drivers of postharvest deterioration, and the barrier functions through which coating counteract them. The review further evaluates polysaccharide, protein and lipid matrices, the nanomaterials used as fillers and active agents, and the functional additives that confer antimicrobial and antioxidant activity. Conventional and emerging application methods are compared, and their effects on physicochemical and sensory quality are assessed. The novelty of this work lies in three contributions: (i) an integrated framework linking coating mechanisms, formulation and application to safety outcomes; (ii) a dedicated treatment of nanoparticle migration, FDA/EFSA regulatory status and consumer perception, areas that are only briefly mentioned in comparable reviews; and (iii) a systematic comparative analysis against recent reviews, which clarifies where this synthesis advances the field. Remaining challenges (industrial scalability, cost-effectiveness and integration with smart packaging) are identified, and research priorities are prosed to support the development of safe, effective and sustainable coatings that reduce food waste and improve food quality. The practical impact of this synthesis is that it provides formulators with a trade-off framework that identifies which coating properties can be optimized simultaneously, and it gives regulators and industry a consolidated account of the migration, toxicity and regulatory evidence needed before commercial adoption.