Study On Preparation And Photoprotective Effect Of Collagen And Collagen Peptides From Skin Of Takifugu Bimaculatus

With the acceleration of open production and management of aquaculture puffer in China,puffer fish processing industry has developed rapidly and many by-products of fish skin processing have not been fully utilized,resulting in waste of resources.In order to promote the application of collagen and collagen polypeptide in cosmetics,collagen and collagen polypeptide were extracted from the skin of Takifugu bimaculatus,and their antioxidant activity and photoaging protection were studied.The analysis of the basic components of the skin of Takifugu bimaculatus showed that the protein accounted for 90.3%of the dry weight of the skin,and the collagen accounted for 94.89%of the total protein.Acid-soluble collagen(ASC)and enzyme-soluble collagen(PSC)were extracted from fish skin by acetic acid dissolution and pepsinase hydrolysis.The purity of both ASC and PSC was over 90%.The physicochemical properties of ASC and PSC were studied.Scanning electron microscopy showed that the ASC was laminated and the PSC was filamento,they are porous.Collagen was identified by SDS-PAGE gel electrophoresis,Fourier transform infrared spectroscopy and ultraviolet full wavelength scanning.The results showed that two kinds of collagen were typical I collagen.The thermal denaturation temperature and thermal shrinkage temperature of PSC were higher than those of ASC.At the same time,collagen has strong emulsifying stability,water absorption and moisture retention.In this paper,the hydrolysis conditions were optimized by single factor test and response surface analysis.Finally,the optimum hydrolysis conditions were as follows:temperature 48.03?,pH 5.35,enzyme dosage 51000 U/g,time 4 h,feed-liquid ratio 0.4%(w/v),actual hydrolysis value 46.79%.In vitro studies have demonstrated that collagen polypeptide from the skin of Takifugu bimaculatus has protective effect on oxidative damage of HES cells induced by hydrogen peroxide.At the concentration of 1000 ug/ml,the smaller the molecular weight of collagen polypeptide,the better the protective effect.Collagen polypeptide also has protective effect on UVB-induced photoaging injury of Hacat cells,and its protective mechanism may be through reducing the level of intracellular reactive oxygen species.The results of photoaging experiment in mice showed that collagen and collagen polypeptide had no effect on the weight of mice viscera,and could effectively improve the skin appearance and tissue structure of mice exposed to ultraviolet radiation.Collagen can enhance the activity of endogenous antioxidant enzymes in serum.Collagen polypeptide can significantly reduce the expression of TNF-a and COX-2 genes,MMP-2 and MMP-9 genes at the level of mRNA,thus inhibiting skin inflammation and collagen degradation in model mice.In summary,this paper synthetically utilizes fish skin waste in the processing of puffer to prepare collagen and collagen polypeptide of puffer,to determine its physical and chemical properties,and to explore its antioxidant activity and skin photoprotection,so as to provide data support for the high value utilization of puffer and the improvement and development of puffer industry chain.