Hybrid chitosan-based nanomaterials from food waste streams: Design, functionalization, and applications in sustainable food packaging

The increasing demand for sustainable and functional food packaging has accelerated research into bio-based materials derived from renewable resources. In this context, chitosan, a biodegradable as well as biocompatible polysaccharide primarily obtained from food waste streams such as crustacean shells, fungal biomass, insects, and agro-industrial byproducts, has appeared as a promising candidate for next-generation food packaging systems. However, challenges related to functionality, scalability, and underutilization of waste-derived chitosan sources limit its broader application. This review highlights a comprehensive overview of sources, extraction, physicochemical properties of chitosan, and food waste valorization strategies, with a unique focus on the design, functionalization, and application of hybrid chitosan-based nanomaterials for advanced packaging systems. Furthermore, recent advances in hybrid chitosan nanomaterials are critically discussed, highlighting their enhanced structural, functional, and stimuli-responsive characteristics. The review systematically explores the green and scalable fabrication techniques and their role in tailoring material performance, together with applications of hybrid chitosan systems in active and smart food packaging. It highlights the relationship between nanostructure design, functional modification, and packaging performance to guide the development of sustainable next-generation packaging materials. These multifunctional systems demonstrate significant potential for shelf-life extension, improving food safety, and enabling real-time quality monitoring. Despite notable progress, challenges related to industrial scalability, cost-effectiveness, and regulatory approval remain critical barriers to commercialization. Therefore, future research directions are proposed, focusing on the development of fully biodegradable, safe-by-design materials, integration of food waste-derived bioactives, and advancement of intelligent packaging technologies within a circular economy framework. Overall, this review emphasizes the transformative potential of hybrid chitosan-based materials in addressing current limitations of conventional packaging and advancing sustainable food systems.