Review of Chitin and Chitosan as Fiber and Film Formers

Chitin is one of the most abundant polysaccharides found in nature. It is often considered a cellulose derivative although it does not occur in organisms producing cellulose. Cellulose consists of β-(1→4)-D-glucopyranose units. In contrast, chitin has the same backbone but the 2-hydroxy has been replaced by an acetamide group, resulting in mainly β-(1→4)-2-acetamido-2-deoxy-D- glucopyranose structural units (GLcNAc). Chitosan is the N-deacetylated derivative of chitin, though this N-deacetylation is almost never complete. A sharp nomenclature border has not been defined between chitin and chitosan based on the degree of N-acetylation [1, 2]. Structural examples of cellulose, chitin, and chitosan can be found in Fig. 1. The structural and chemical features will be elaborated on in a later section.