Biopolymers as Sustainable Armour for Extending the Shelf Life of Vegetables: Mechanisms, Applications and Emerging Trends

Vegetables remain metabolically active long after harvest and continued respiration, transpiration and enzymatic turnover drive rapid postharvest deterioration. Global assessments indicate that close to one-third of harvested produce is lost before consumption and Indian estimates place vegetable losses at 5–15 per cent, rising to nearly 50 per cent for highly perishable commodities such as tomato within two weeks of ambient storage. Petroleum-derived plastics and synthetic wax coatings have long served as postharvest protective barriers, but concerns over microplastic accumulation and toxic residues such as N-nitrosomorpholine have accelerated interest in biodegradable alternatives. This review synthesises current understanding of biopolymer-based edible coatings, derived from polysaccharides, proteins, lipids and their composites, as a sustainable protective “armour” for vegetables. It examines the molecular basis of their barrier and bioactive functions, including modulation of gas and moisture exchange, ethylene management, enzymatic browning inhibition and antimicrobial/antioxidant delivery. Coating application techniques and advanced nanocomposite and electrospun formulations are discussed alongside safety, regulatory and economic considerations. Representative experimental studies on tomato, carrot, spinach, pointed gourd and green chilli illustrate practical efficacy. Persistent limitations of mechanical weakness, moisture sensitivity and unresolved nanomaterial safety continue to constrain large-scale industrial adoption of these coatings.