Characterization of Acid-soluble Collagen from the Skin of Hammerhead Shark (Sphyrna lewini )

Abstract

The characteristics of the acid-soluble collagen (ASC) from the skin of hammerhead shark (Sphyrna lewini) (ASC-H) were investigated and compared with those of calf skin collagen (CSC). ASC-H with a yield of 4.23 ± 0.54% (based on the wet weight of skins) contained Gly (227 residues/1,000 residues) as the major amino acid and had imino acids of 205 residues/1,000 residues. Amino acid composition, sodium dodecyl sulfate polyacrylamide gel electrophoresis pattern and Fourier transform spectroscopy (FTIR), confirmed that ASC-H was mainly composed of type I collagen. The peptide map of ASC-H was different from that of CSC, suggesting the differences in amino acid sequences and conformation. Td of ASC-H was 16.89C, which was similar to those of cold-water fishes but significantly lower than those of tropical fish species and mammals. ASC-H exhibited high solubility in pH (1-4) and low NaCl concentrations (≤3%). In addition, the lyophilized collagen displayed loose, fibrous and porous ultrastructure. Practical Applications At present, large quantities of by-products, accounting for 50–70% of the original raw material, are generated during the process of aquatic products processing industry. Therefore, optimal use of these by-products is a promising way to protect the environment and produce value-added products to increase the revenue of fish processors. Recently, many scientists have focused their interests on isolation and characterization of collagens extracted from skins of aquatic organisms. However, no information regarding acid-soluble collagen (ASC) from skins of Hammerhead shark (Sphyrna lewini) has been reported. The aim of this study was to isolate and characterize ASC from skin of Hammerhead shark in comparison with type I collagen from calf skin (CSC). Therefore, the collagen extracted from the skin of hammerhead shark could bring considerably economic benefits as a substitute for mammalian collagen.