Purification And Functional Properties Of Walnut Albumin And Antioxidant Petides

Defatted walnut meal is raw material,and we make walnut albumin through the method of alkali extraction and acid precipitation.The antioxidant activity in vitro and in vivo of albumin is determined.The enzymolysis conditions of walnut albumin are optimized and the antioxidant activities of walnut polypeptide are determined.Evaluation of the possible mechanism of walnut albumin by distribution and abundance of intestinal microflora in mice.The main results are as follows.The antioxidant ability of albumin showes dose relationship,and its reducing power reach to 85.63% at 5.0mg/mL,the same concentration with Vc,and the radical scavenging activity of ABTS reaches to 100% at 1.5mg/mL,and the radical scavenging activity of hydroxyl radicals can reach 100% at 16mg/mL,and the radical scavenging activity of DPPH and Fe2+ can reach 100% and 72.25% respectively at 0.5mg/mL.The in vivo antioxidant test in aging mice fed albumin is determined by the level of SOD,GSH-PX,MDA and T-AOC in liver homogenate and brain homogenate and serum,that can maintain and even improve the level of SOD,GSH-PX and T-AOC index and maintain or reduce the content of MDA,what Proves albumin can improve the antioxidant ability of mice.By using method of single factor and response to determine the technology research of process conditions about the albumin enzymolysised by alkaline protease,and the hydrolysis degree of protein and the radical scavenging ability of enzymatic hydrolysate is determined.Optimal technological conditions is optimized as the following: hydrolysis temperature of 45?,Alcalase concentration of 8000U/g,substrate concentration of 4%,pH of 9.5 and hydrolysis time of 2.5h.The polypeptide extracts prepared Under the optimum hydrolysis conditions has dose relationship.The scavenging efficiency of DPPH,Fe2+,ABTS is 92.63%,89.65% and 74.37%,respectively,at 0.5mg/mL and the scavenging efficiency of ·OH is 84.07% at 5mg/mL what show that polypeptide extract of walnut albumin has good antioxidant activity.Three components,>10,10-3,< 3kDa are obtained by ultrafiltration and showe a good dose relationship.Further purification of < 3kDa components by Sephadex G-25.We determine the 16 S rRNA of mice feces to explore the effect of feeding walnut albumin on the intestinal microogranisms of mice.After the amplification and sequence of mice feces.The intestinal microflora of mice in each group are analyzed by OTU analysis,species annotation,sample complexity analysis and multi sample comparison analysis.The results showed feeding albumin for aging model mice has the function of maintaining the relative abundance of harmful microorganisms such as Helicobacter and probiotics suchu as lactobacillus in some degree.