Extraction and physicochemical properties of collagen from white fish of Taihu Lake ( Erythroculter ilishaeformis)

Collagens were extracted from the fin, scale, skin, muscle, bone and swim bladder of white fish at different p H.HPLC, SDS-PAGE, peptide mapping and DSC were used to investigate the compositions and physiochemical properties of the collagens, which were extracted from different parts of white fish.The results showed that, collagens could be more soluble in the acidic p H range from 3 ~ 4, while the solubility decreased under neutral and alkaline condition. Extraction ratios of collagens from skin and swim bladder were 18.80% and 15.95% respectively, which were higher than those of other white fish parts.Similar peptide maps of collagens extracted from different parts of white fish indicated that primary structures of these collagens were quite similar in terms of amino acid sequence.Nearly 1/3 of the total amino acid was Gly, and a high level of Pro and Hyp up to 154.2¹99.0 residues/1000 residues.The collagens from all parts of white fish were comprised of two kinds α chains ( α1and α2) and classified as type I collagens.The denaturation temperatures of these collagens were between 34.16³6.40 ℃.The collagens extracted from different parts of white fish had good similarity in composition, structure and physicochemical properties.