Chitosan and chitosan derivative-based composite packaging for food preservation: Preparation strategies, performance modulation, and application prospects.

As naturally derived polymeric materials, chitosan and its derivatives exhibit considerable promise in food preservation, owing to their biodegradability, non-toxicity, structural tunability, and favorable mechanical properties. This review critically surveys recent progress in chitosan-based food preservation materials, with emphasis on preparation strategies, performance modulation, smart packaging functionalities, and prospective applications. The sources and intrinsic physicochemical characteristics of chitosan are examined, alongside various functionalization routes, including physical blending, chemical modification, and derivative synthesis. The systematic discussion then focuses on how these modification strategies-either independently or synergistically-regulate the key performance parameters of chitosan-based films and coatings, such as mechanical strength, water vapor and gas barrier properties, antibacterial and antioxidant activities, thermal stability, optical transparency, and biodegradability. Special attention is given to the emerging role of intelligent packaging in modern food preservation, and the mechanisms by which chitosan-based materials enable real-time, visual monitoring of food freshness through the integration of pH-sensitive dyes or volatile amine sensors are analyzed in detail. Future directions for chitosan and its derivatives in this field are outlined, with particular focus on their integration into smart packaging systems, and prioritized research avenues are proposed for further performance optimization, industrial scale-up, and commercialization. This review aims to provide a valuable reference for the development of efficient, sustainable, and intelligent food packaging solutions.