Novel gelatin-based materials of fish by-products: a systematic review on the functional properties of biofilms, nanocomposites, and nanofibers for food and biomedical applications

The growing global fish production has generated large volumes of fish waste and by-products, posing significant economic and environmental challenges. Recycling these materials has emerged as a promising strategy to produce high-value biomaterials from underutilized resources. In this context, this study aimed to conduct a systematic literature review, structured according to the Population-Concept-Context (PCC) framework and reported following the PRISMA guidelines, based on a search of PubMed, Scopus, and Web of Science covering publications from 2015 to 2025. The review focused on technological innovations in gelatin extraction from fish by-products and the development of biofilms, nanocomposites, and nanofibers for food packaging and biomedical applications. After applying the eligibility criteria, 45 studies were included. The analysis showed that electrospinning and solvent casting were the predominant fabrication techniques, reflecting the intrinsic molecular characteristics of fish gelatin. Biofilms and nanocomposite films were mainly developed for food packaging because of their favorable mechanical and barrier properties, whereas nanofibers were predominantly explored for biomedical applications owing to their porous architecture and high surface area. The incorporation of natural or synthetic additives generally improved the mechanical, thermal, barrier, and biological properties of fish gelatin-based materials. Despite these advances, the review identified important research gaps, including the lack of standardized extraction and characterization protocols and the limited correlation between structural characterization and functional performance. Future studies should establish robust structure–property relationships to accelerate the industrial application of fish gelatin-based materials.