Isolation and characterization of collagen from fish waste material- skin, scales and fins of Catla catla and Cirrhinus mrigala

The collagen of skin, scales and fins of Catla catla and Cirrhinus mrigala were isolated and characterised. Nine fishes of each fish species of three weight groups were collected from a commercial fish farm. Collagen characterisation using SDS-PAGE revealed the molecular weights (kDa) of the C. catla skin, scales, and fins which ranged from 120 to 210, 70 to 201, and 68 to 137 kDa, respectively. The size of the collagen of C. mrigala skin, scales and fins ranged from 114 to 201, 77 to 210, and 70 to 147 kDa, respectively. Glycine and alanine were the most abundant amino acid, whereas tryptophan was totally absent in all selected tissues. Thus, significant variation exists in type of collagen and amino acid profile within the weight groups of the two fish species. The imino acid (proline and hydroxyproline) contents estimated in C. catla and C. mrigala skin (161-165 and 160-168), scales (155-159 and 152-161) and fins (162-171 and (152-155) residues/1,000 residues, respectively. The proximate analysis was also performed for skin, scales and fins. The maximum protein content of the skin was determined as 26.10 % and 22.90 % in the C. catla and C. mrigala, respectively, from the W-3 weight group. The scales of the W-3 weight group exhibited maximum protein contents of 25.90 and 21.77 % for C. catla and C. mrigala, respectively. The maximum protein contents (19.04 % and 18.12 %) were recorded for C. catla and C. mrigala, respectively in the fins.