Chitosan

What is chitosan chitosan? Chitosan is a modified carbohydrate polymer derived from the chitin component of crustacean shells such as crab, shrimp, squid, etc. "Chitin is" deproteinized, desalted, deacetylated ". (Razdan, A. and Pettersson, D 1996, 387). It is dietary fiber, which means that it can not be digested by human digestive enzymes (Razdan, A. and Pettersson, D. 1996). Chitosan consists of NH 4 + (ammonium) groups attached to the polyglucosamine chain.

Chitosan is a natural polysaccharide composed of glucosamine and N-acetylglucosamine and has various molecular weights and degrees of deacetylation. The amino group of chitosan has a pKa value of about 6.5 so chitosan is positively charged and soluble in a weakly acidic solution and its charge density is adjusted to the extent of pH and deacetylation Dependent. Chitosan is believed to promote the transport of polar drugs across the epithelium through a combination of strong mucoadhesive properties and transient opening of cell-cell tight junctions. Chitosan is also non-toxic and non-irritating to the nasal membrane. The chitosan solution can be easily prepared by dissolving the solid in a dilute acid solution such as acetic acid, citric acid, lactic acid or glutamic acid. Chitosan salts such as chitosan glutamate or chitosan hydrochloride can be easily dissolved in water.

Chitosan is a naturally abundant aminated polysaccharide. Its chemical properties give chitosan unique functional properties. The main feature of chitosan is its degree of acetylation and molecular weight. These are decisive for the functional properties of chitosan, from solubility and material forming ability of chitosan to biodegradability and various biological activity characteristics. The great potential to use chitosan in various fields has long been recognized. The biological properties of chitosan makes it particularly suitable for applications related to agriculture, food and environmental engineering applications. In this chapter we will explore the relationship between the chemical properties of chitosan and its main functional properties.

The main NH 2 group of chitosan is an important structural element in its various applications. Chitosan is insoluble at neutral and alkaline pH, whereas under acidic conditions amine groups from chitosan are protonated to produce soluble polysaccharides. Hydrolysis can occur in a strongly acidic medium, which results in a reduction in the viscosity and molecular weight of chitosan. In recent years, there has been great interest in the correlation between the physicochemical properties of chitosan based materials and the origin, molecular weight and degree of deacetylation of chitosan based materials (Shukla et al., 2013).