Chitin, Chitosan, and their Derivatives from Seafood Waste and Processing Byproducts

Processing of crustaceans such as shrimp, crab, etc., or molluscs, e.g., squid generates large amounts of byproducts, especially shells and squid pens. Improper disposal of those byproducts may cause deleterious implications on environment and human health. The valorization of shells or squid pens via conversion to several high-value bioactive compounds could pave a way for sustainable utilization of marine resources. Crustacean shells and squid pens serve as a potential source of chitin, which can further be deacetylated into chitosan (CS), a positively charged polysaccharide that exhibits biocompatibility and biodegradability. Derivatization or degradation of CS can enhance bioactivities including antioxidant, antimicrobial, antitumor activities, etc. The present chapter covers the established methods of chitin and CS extraction from seafood processing waste. Moreover, the methods for preparation of various CS derivatives, e.g., chitooligosaccharides or chemically modified CS are also revisited. Recent trends in applications of CS derivatives in the food sector are also explored. Furthermore, CS derivatives for biomedical uses are addressed.