Extraction Of Collagen Of Goose Skin And Studies On The Character Of Its Biologically Active Peptide

As a local breed, Zhedong goose enjoys a wide distribution in Zhejiang Province. The goose skin was used to tanning, but at present the demand of goose skin for the tanning industry was reduced dramatically, thus most of the goose skin was littered as waste, which led to the problem of environmental pollution as well as the waste of biological resourses.Studies showed that collagen could be obtained with methods such as acid process, alkaline process, enzyme process, while collagen peptide was generally obtained by the hydrolysis of collagen peptide collagen or gelatin. Collagen peptide has many biological functions, such as anti-oxidation, reducing blood pressure, promoting the mineral absorption, improving immunity, antibiosis and so on.This paper studied on goose skin to find the optimal technique to extract collagen peptide and then worked on its biological character with experiments in vivo and vitro. Main results are as follows:1The optimal conditions of extracting goose skin collagen with acid were determined: used ether to skim in the pretreatment; used lactic acid as the leaching solution, pH1.9, the ratio of material to liquid1:50(g/mL)、extracting time60h.Under these conditions,we got the highest extracting level (30.12%) and the purity reached92.01%. The collagen we got with this method was typical type I with triple helix structure。2From flavourzyme, papain, alkaline protease and trypsin, we chose flavor protease, in company with papain to hydrolyze collagen, with indexes of DH, scavenging capacity of DPPH-and bitterness, the best extraction technology after orthogonal test was:papain:flavor protease=1:1, enzyme quantity4000U·g-1, temperature50℃, pH6.0, hydrolysis time5h. The gained collagen peptide had the highest degree of hydrolysis and scavenging capacity of DPPH·,28.3%and89.2%respectively, and no bitter taste. The forth peak P4was separated and purified by Sephadex G-75and showed the best sensory evaluation, solubility and emulsification.3D-galactose induced aged mice model was established to study the effects of collagen polypeptide P4on the antioxidant in vivo. Through safety tests we found P4did no harm and sensitization to the growing of B16cells. On the basis of the results, five groups were classified:normal control group, D-galactose induced aged model group, low dose of goose skin collagen peptide group, high dose of goose skin collagen peptide group and VE control group. The levels of TC,LDL-C,LDL-C/HDL-C were significantly decreased while the levels of HDL-C,HDL-C/TC were improved; what’s more, the results of MDA content, SOD, TAC, GSH-Px and CAT activity showed the collagen peptide significantly improved the antioxidant ability in vivo. And the immunity ability also increased significantly which was deduced from the data of spleen index and thymus index.4B16melanoma cells in mice model were cultivated in vitro to study the effects of collagen polypeptide P4on the synthesis and mechanism of melanin. Studies have shown that P4has no toxicity to cells. After incubation with peptide at a dose of100μg/ml, the melanin and the tyrosinase activity were lowed33.11%(P<0.01) and27.76%(P<0.01) respectively. Furthermore, the level of GSH was reduced while the level of GSSH was increased by adding peptide to the nutrient solution which effectively improved the cells’reduction ability. When the concentration of collagen peptide P4arrived50μg/ml, the content of cAMP decreased40.75%(P<0.01), thus helped inhibit the synthesis of melanin.