Marine-Derived Edible Biopolymer Coatings for Seafood Preservation: Structure–Property–Interface Relationships

Marine-derived edible biopolymer coatings are increasingly investigated for seafood preservation, yet their reported performance remains difficult to compare because polymer characteristics, coating formation, interfacial behavior, and preservation outcomes are frequently evaluated independently. This critical narrative review synthesizes literature published primarily from January 2016 to June 2026, while retaining earlier foundational studies when mechanistically relevant. Collagen, gelatin, chitosan, alginate, carrageenan, and emerging marine-derived materials are examined through a structure–property–interface–performance framework that distinguishes evidence from isolated polymers, preformed films, model substrates, and coatings applied directly to seafood. The available evidence shows that polymer identity and dry-film properties alone do not reliably predict coating performance on moist seafood surfaces. Molecular characteristics, solution rheology, wettability, spreading, adhesion, hydration stability, coating continuity, and active-compound retention and release jointly determine preservation efficacy. Direct seafood studies demonstrate meaningful shelf-life extensions in selected systems, but remain highly heterogeneous and frequently lack quantitative characterization of coating thickness, adhesion, interfacial stability, and release behavior. Evidence is concentrated mainly in refrigerated fish and crustaceans, whereas mollusks, cephalopods, processed aquatic products, frozen systems, and pilot-scale applications remain underrepresented. Future progress requires standardized molecular and formulation reporting, direct quantitative characterization of the coating–seafood interface, integrated microbiological, oxidative, physicochemical, and sensory validation, and demonstration of safety, scalability, economic feasibility, and environmental benefit.