ABSTRACT
Chitin is a dietary fiber-based polysaccharide that is widely distributed in the natural world, including in crab and shrimp shells; the epidermis or shells of insects, such as beetles and grasshoppers; shellfishes, such as hard clams or oysters; squid bones; and the cell walls of fungi, such as mushrooms and yeast. It is a naturally occurring high-molecular-weight substance that provides protection to living organisms. Therefore, it serves a role analogous to cellulose in the vegetable kingdom. The main body of chitin is chemically a polysaccharide with a molecular weight exceeding 1,000,000 kDa in which N-acetyl-D-glucosamine residues are β-1,4-linked. Chitosan is a cationic polysaccharide and is commonly derived from chitin. It is a polysaccharide in which 2-amino-2-deoxy-D-glucose units are β-1,4-linked. Its molecular weight is less than that of chitin because it is manufactured via the deacetylation of chitin. In other words, to make chitosan, it is necessary to remove the N-acetyl group from the chitin by a process known as deacetylation.
