Study On Preparation And Characters Of Cod Skin Collagen And Collagenous Oligopeptide

Cod skin is the main by-product of cod processing industry. These underutilized resources is abundant and origin concentrated, which is high valueable to exploite and utilize both in environment and society. Collagen is the chief component of cod skin, 57.54% of total protein, that has unique structure and biological function and is widely used in chemical industrial, biomedical material and food industry. Collagenous oligopeptide which possess good absorbency and bioactivities also has been beget widespread concern.This study foucuses on investigate the extraction technology of collagen and Collagenous oligopeptide from cod skin. Then, the structure, properties and biological activities of products were also researched. Major content of the paper as following:The pretreatment technic of cod skin stuff was ascertained. Firstly, the cod skin was defatted with organic reagents. the optimum parameters were: temperature 4℃, hexane, soak time 8 hours, and the removal rate of fat was 91.18%. Then, the cod skin was removed petit protein with sodium chloride. the optimum parameters were: temperature 4℃, 7.5% NaCl, soak time 12 hours, and the removal rate of petit protein was 46.09%, at same time, collagen loss was little.Collagen was isolated from cod skin by acid-enzyme binding method at temperature 4℃. The results indicated that, the optimal extraction conditions were as follow: pepsin addition of 1.0%, solid/liquor ratio of 1:40, extraction time of 24 hours, citric acid concentration of 0.20 mol/L. Under this condition, the yield of the cod skin collagen was 48.67%.Then, Sodium chloride was applied to precipitate collagen, and ultrafiltration was used for desalination and purification of collagen. The molecular weight cutoff of cellulose acetate membrane is 30,000 Da. The best techniques were confirmed as follow: intermittent operation, pressure 1.0 MPa, injection times 3 hours, and desalting rate was 89.98%, loss rate of collagen was 8.75%.The hydrolytic characteristics of cod skin by pepsin were studided. The enzymatic dynamics equation was, -rs=(2.9004E-3×[S])/([S]+0.2156).The isolated protein was confirmed by different phsico-chemical techniques. FTIR sepectroscopy and CD sepectrum analysis showed triple helix is complete. UV epectrum accord with character of collagen. The result of SDS-PAGE suggested the prepared collagen was typeⅠcollagen. The prepared collagen is in line with typical amino acids of collagen. Its thermal stability was not good as terrestrial animals by DSC.The enzymatic hydrolysis technology of Bioactivities of collagenous oligopeptide was investigatied. Alcalace and parenzyme were more suitable enzymes. Double-enzyme composite hydrolysis technology was conducted to obtain a lot of lower relative molecular weight peptide product. The optimal scheme was: admixture, enzyme/substrate ratio of 2500 U/g, pH 8.5, temperature 50℃, time 6 hours and the degree of hydrolysis is 29.71%.The molecular weight distribution of prepared Collagenous oligopeptide was survey and evaluate by HPLC. Result showed most of the relative molecular weight present to below 1000 Da, The vitro detection methods were applied to evaluate antioxidant bioactivity of prepared Collagenous oligopeptide. The results show that there is good antioxodation effect of the peptide.