Abstract: Aquatic products, rich in protein and unsaturated fatty acids, hold an important position in the food industry. However, they are highly susceptible to quality deterioration such as spoilage, oxidative degradation, and enzymatic browning during storage and processing, thereby reducing their edible and commercial value. As a carboxymethylated derivative of chitosan (CS), carboxymethyl chitosan (CMCS) exhibits excellent water solubility, biocompatibility, antimicrobial activity, and antioxidant properties, demonstrating broad application prospects in the preservation and processing of aquatic products. This review summarizes the molecular characteristics, functional properties, and preparation methods of CMCS, and examines its practical applications in the preservation, processing, and intelligent packaging of aquatic products. Additionally, the future prospects of CMCS in the processing and preservation of aquatic products are discussed, aiming to provide references and a theoretical basis for the innovative application of CMCS in the processing and preservation of aquatic products and for technological advancements in this field.

Key words: aquatic product application; processing and preservation; carboxymethyl chitosan; smart packaging