Recent advances in chitosan-based active composites for sustainable food packaging and preservation

The global transition toward a circular economy has positioned chitosan (CS) as a premier biopolymer for replacing petrochemical plastics; however, a significant knowledge gap persists between laboratory-scale innovation and industrial-scale viability. This review provides an integrated synthesis of recent advances in CS-based composites, specifically addressing the functionality-scalability paradox that hinders commercial adoption. We analyze the technical performance of CS modified through biopolymer blending (starch, cellulose, alginate, gelatin), chemical cross-linking, and the incorporation of bioactive fillers including metallic nanoparticles, carbon dots, and natural extracts. Critical insights reveal that while CS composites significantly extend the shelf life of produce, meat, and seafood by regulating internal atmospheres and inhibiting microbial growth, their industrial application is restricted by high moisture sensitivity and processing brittleness. Furthermore, we uniquely evaluate the regulatory landscape, highlighting that stringent migration limits for metallic nanoparticles (Ag, ZnO, TiO 2 ) necessitate a strategic shift toward bio-based reinforcements. Future research must move beyond iterative material testing by using AI-assisted material design to optimize synergies among components, by developing extrusion-ready thermoplastic CS graft copolymers, and by implementing closed-loop waste-to-wealth models that utilize agricultural residues as both the polymer source and bioactive filler. By bridging material science with regulatory frameworks and economic feasibility, this review outlines a definitive roadmap for the commercialization of the next generation of active and sustainable food packaging.