Extraction and characterization of acid soluble collagen (ASC) from airbladder of striped cat fish (Pangasius hypophthalmus)

Abstract

The aim of the present study was to extract high pure acid soluble collagen (ASC) from the airbladder of striped cat fish (Pangasius hypophthalmus). ASC was extracted and its physico-chemical characterization was carried out to confirm the purity and structural integrity of extracted collagen. The yield of ASC extract was determined to be 73.4 plus or minus 0.8 percentage of the dry weight of raw material. Amino acid analysis revealed the glycine content as 243.0 plus or minus 1.3 residues per1000 residues, imino acids as 186.1 plus or minus 1.4 residues per 1000 residues respectively and was shown to be devoid of non-collagenous amino acids such as tryptophan. Electrophoretic analysis confirmed the subunit pattern of type I collagen and showed that it also contained beta and gamma subunits. UV/Vis absorption and FT-IR analysis demonstrated the primary and secondary structural integrity of collagen and also indicated that no denaturation had occurred during extraction process. H-NMR analysis validated the structural integrity of collagen triple helix. The denaturation temperature (Td) of ASC was assessed as 33.3 degree celsius. The air bladder collagen extracted from striped cat fish is of high purity and belongs to type I with intact triple helical structure.