Polymeric Biocoatings for Postharvest Fruit Preservation: Advances, Challenges, and Future Perspectives

The growing demand for fresh fruit, coupled with high postharvest losses, highlights the need for sustainable and effective preservation technologies. In this context, polymeric biocoatings are emerging as a promising alternative to conventional synthetic packaging, thanks to their biodegradability, film-forming capacity, and potential to incorporate bioactive compounds. This review article summarizes recent advances in the development of coatings based on polysaccharides, proteins, and nanomaterials, analyzing their physicochemical, functional, and sensory properties, and the main conventional and emerging application methods used in fresh fruit. It also highlights the role of phenolic compounds and essential oils as antioxidant and antimicrobial agents, along with the valorization of agro-industrial by-products under circular economy schemes. Finally, it discusses the challenges associated with standardization, industrial scaling, and consumer acceptance, proposing future perspectives aimed at designing multifunctional systems that extend the shelf life and improve the quality of fresh products, in line with environmental sustainability objectives. Unlike recent reviews, this work unifies structure–function relationships with quantitative comparisons of coating performance across fruits. It further contributes a critical evaluation of emerging application technologies and their technological and regulatory readiness, offering a distinctly more integrated perspective.