Development of chitin nanofiber-reinforced chitosan composite coatings for banana preservation

Development of eco-friendly packaging materials is essential to extend the shelf life of perishable fruits and vegetables, reduce food wastage, and minimize dependance on petroleum-based plastics. Here, we report a novel high-performing chitosan-based film reinforced with chitin nanofibers (ChNFs) derived from shrimp shell waste. Incorporation of ChNFs markedly enhanced UV-shielding, water resistance, thermal stability, mechanical integrity, and barrier properties of chitosan films. Such efficiency is owed to the high strength and stiffness of ChNFs and their strong interfacial interactions with the chitosan matrix. Among all formulations, the films containing 50 wt% ChNFs (CS50) exhibited optimal multi-functional performance, including nearly complete ultraviolet (UV)-blocking, 95.4% and 124.6% improvements in tensile strength and Young's modulus, respectively, as well as 16.2% and 41.1% reductions in water vapor permeability and oxygen transmission rate compared with neat chitosan films. When applied as a dip-coated layer on the banana epidermis, the CS50 coatings significantly delayed banana ripening by suppressing respiration and ethylene production, while maintaining weight, pH, and firmness during 12 days of storage. Unlike polyethylene packaging, which traps moisture and allows oxygen ingress, the CS50 coatings enabled controlled moisture release, while effectively retarding oxygen permeation, thereby minimizing physiological deterioration. Therefore, this study demonstrates a scalable strategy for converting seafood waste into advanced bio-based coatings with superior barrier performance and protective functions, offering a promising eco-friendly alternative to conventional plastic packaging for preserving fresh food produce.