Studies On The Development Of Gonad, Embryo, Larva And Juvenile Of Acrossocheilus Fasciatus

A high yield of beef production and consumption as a food in China, it results in a greatdeal of cattle skin over40million pieces each year. Most cattle skin materials were directly provided forthe leather industry at lower prices, which only40prsent of them was put into use for leather manufacture.Therefore, a large part was taken to be as waste management, or directly landfill. It leads to a waste ofresources or causes a pollution of the environment.Cattle skin is rich in collagen, which is a valuable biological resource. With its excellentbiocompatibility, biodegradability and weak antigenicity, collagen is widely used in the field of functionalfoods, cosmetic, beverage, plastic surgery too.This thesis determinationed the content of collagen in the cattle skin, the composition of cattle skinwas also analyzed．The collagen from cattle skin has been extracted by using acid swelling—pepsindigestion method，The optimal processing conditions were obtained by orthogonal experiments．Thephysical and chemical properties of cattle skin collagen were studied, too. In order to obtain smallcollagen petides, used Papain and protamex as two-complex proteases to further hydrolyzed cattle collagen.The optimal processing conditions were obtained by orthogonal experiments, and the physical andchemical properties of secondary hydrolysates were determined.Main research results were as follows:1. The content of total protein was32.92%±0.025, Crude fat was0.84%±0.096, moisture level was61.73±0.187, collagen was26.2%of cattle skin in my experiment.2. The collagen from cattle skin has been extracted by using acid swelling—pepsin digestion method.Effects of enzyme addition, temperature and extract time as well as solid-liquor ratio on extractionefficiency of collagen were investigated in this paper．The optimal processing conditions wereobtained by orthogonal experiments as follows:0.5mol／L acetic acid as extraction solvent, theadded pepsin dosage of3000U/g and the ratio of material to liquor1：30（g/ml）, extraction at30℃for8h, the recovery yield of the collagens was61.7%. The maximum absorb wavelength ofsample is232nm by UV scan, which is consistent with the Sigma product.3. Papain and protamex were chosen as the two-complex proteases to further hydrolyzed cattlecollagen through the experiment. Then the optimal conditions of hydrolyzing the cattle collagenwith papainase had been found by single factor experiments and orthogonal tests as follows:temperature60℃, pH=6, time6h and the added papainase dosage of6000U. Thehydrolyzed degree of the cattle skin collagen was26.7%, and hydrolysis of the hydroxylradical scavenging rate reached30.2%under these conditions. The protamex optimalconditions of hydrolyzing the cattle collagen as follows: temperature55℃, pH=8, time8h andthe added protamex dosage of8000U,from which the hydrolyzed degree of the cattleskin collagen was36.1%, and hydrolysis of the hydroxyl radical scavenging rate reached24.5%.