The Technical Research And Activity Analysis Of Whey Antioxidant Peptide

As a functional factor which has health promotion, the bioactive peptide becomes the hottest research subject at home and abroad. The bioactive peptide which is produced by using lactoprotein as material not only has functionality, but also can provide extra nutrients. Therefore, it has a good develop prospect. The milk antioxidant peptide is a kind of bioac-tive peptide with the ability of scavenging free radical and inhibiting lipid peroxidation reaction. For food preservative, disease preventionit, delay senility and functional foods research, it has a very important significance to study it in deep.During the cheese making, it separates a lot of whey which is chiefly made of whey protein. Whey protein has high nutritional value bacause of the full kinds and high contents of amino acids. Producing antioxidant peptide by whey can change waste into useful material, make full use of whey nutrients and avoid the pollution; The bioactive peptide derived from whey protein increases the added value of dairy products, develop the functional food resarch and has better heath and economic benefits. So it will promote the development of the dairy industry.In this paper, I explored the optimum parameter of producing antioxidant peptide by whey protein concentrate(WPC80); Separated the antioxidant peptide by ultrafiltration and analyzed its component. The main results as fllows:(1)Design the process of producing whey antioxidant peptide by Trypsin. Optimization of the enzymolysis was carried out by the single factor tests. The optimum condition of the enzymolysis as follows:with clearance of DPPH as criteria, concentration was3%, time was90min, temperature was50℃, pH was8.0. Based on this theory, further optimize the condition of enzymolysis.(2)The crucial conditions were the temperature(A), pH(B), and the amount of the enzym(C). The regression equation was obtained by Box-behnken response surface test.It was:Y=45.79-4.32A+2.91B-1.42C+3.71AB+3.21AC+0.43BC-6.57A2-5.08B2-5.66C2. The optimum condition of the enzymolysis was48.31℃,8.08, and1.78%. In this condition, the clearance of DPPH was47.76%. The result was proved accurate and reliable, and had statistical significance.(3)Design the process of producing whey antioxidant peptide by the Fermented. The ratio of L. bugaricus cultured and streptococcus thermophilus was1:1, and the culture cycle was24h. Optimization of the enzymolysis was carried out by the single factor tests. The optimum condition of the enzymolysis as follows:with clearance of DPPH as criteria, concentration was10%, time was24h, temperature was37～47℃, pH was6.0～6.8. The inoculation was3%～5%. Based on this theory, further optimize the condition of fermentation.(4)Orthogonal experiment design was used to analyze Temperature(A), pH(B), and The inoculation(C) which could affect the quality of the antioxidant activity of the product. The optimum condition of the fermentation was37℃,6.8,4%. In this condition, the clearance of DPPH was66.95%.(5)Separated the substrate and the fermentation by ultrafiltration. Found the ultrafiltrate has the highest antioxidant activity by the Membranes of5kDa. I compared the antioxidant activity of the substrate with the fermentations. The fermentation had higher antioxidant activity. Its clearance of DPPH was79%. The reason was enzyme specificity and the diversity of lactic acid bacteria protein enzymes.(6)Molecular weight of whey fermentation products with antioxidant activity focused on less than2KDa by Tricine-SDS-PAGE electrophoresis; By amino acid analyzer, more than70%amino acids were Hydrophobic amino acids and aromatic ring amino acids which have close relations with antioxidant activity. The whey antioxidant peptide was full of the essential amino acids for human body and children, so it can be used for the functional food development..(7)From process principle, process conditions and the nature of the final product to compare the enzymolysis with the ferment. The fermentation had some a dvantages of the functional food development. And pay attention to a reasonable prospect of the development in the functional food of whey antioxidant peptide.(8)The antioxidant activity of the fermentation was much higher than Set-yoghurt and whey. The Set-yoghurt had some antioxidant activity, and the antioxidant activity of the whey is lowest. The point of the whey functional beverage was how to improve the concentration of whey or whey peptide at the lower cost.