Abstract

Chitosan is a naturally available biopolymer. It has been prepared by alkaline N-deacetylation process of shrimp (Crangon crangon) chitin and fish (Labeorohita) chitin. The physico-chemical properties such as the degree of deacetylation (DD), solubility, water binding capacity, fat binding capacity and chitosan yield have indicated that shrimp shell and fish scale waste are good sources of chitosan. The deacetylation value of shrimp shell chitosan, fish scales and commercial chitosan was found to be 76, 80 and 84%, respectively. The crystalline index (CrI) of fish and shrimp shell was 84 and 82%. Fat binding capacity of fish chitosan, shrimp chitosan and commercial chitosan was found to be 226, 246 and 446%, respectively. Fourier transforms infrared spectroscopy (FTIR) spectra presented a detailed structure of α-chitin with O-H, N-H and CO stretching movements. Structural differences between shrimp chitosan and fish chitosan were studied by using FTIR, thermo-gravimetric analysis (TGA), X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). FTIR spectra were used to determine the chitosan degree of deacetylation (DD). Characteristic properties of extracted chitosan were found to depend upon the source of origin and degree of deacetylation.

Key words: Chitosan, fish scales, shrimp shell.