Study On Preparation And Activity Of Antioxidant Peptide From Seabuckthorn Seed

China's seabuckthorn resources is No.1 in the world,There are many seabuckthorn processing enterprises,mainly concentrated in the seabuckthorn juice,seabuckthorn seed oil development.In the process of shallow development and utilization of seabuckthorn resources,these enterprises produce large quantities of seabuckthorn seed meal which are discarded or just used as fodder,in which containing 25% to 30% proteins of them are not utilized reasonably and efficiently.In this thesis,seabuckthorn seed meal protein was extracted from seabuckthorn seed meal which produced after seabuckthorn seed oil extraction,and the optimum technological conditions for preparing antioxidant active peptide by enzymatic hydrolysis were studied.The main research contents and research results are as follows:(1)Optimize the process of seabuckthorn seed meal protein extraction.The technology of extracting seabuckthorn seed meal protein by alkali dissolving was optimized.The optimal protein extraction conditions of seabuckthorn seed meal used in this experiment are as follows:the extraction time was50 min,the pH value was12,The ratio was1:12,the temperature of extraction was50?,the pH of acid precipitation was 4.0.The content of seabuckthorn seed meal protein after vacuum freeze-drying was80.03%.(2)To study the preparation process of seabuckthorn antioxidative active peptides.TheThe ABTS clearance rates of the polypeptides obtained from alkaline protease,neutral protease and flavour protease,and papain digestion of seabuckthorn seed meal protein by single factor experiments were 26.03%,25.00%,23.53%,and 20.14%,respectively.Consider the combination,combine the flavor enzymes and neutral enzymes to Enzymolysis Seabuckthorn protein.Single factor experiments confirmed that the highest ABTS clearance rate was 26.72% for seabuckthorn polypeptides obtained when the ratio of flavor enzyme to neutral enzyme was 3:2,and the enzymatic hydrolysis effect was better than that of any single enzyme.The results of the single factor experiment of the amount of complex enzyme,substrate concentration,the hydrolysis time,and the hydrolysis temperature during the enzymatic hydrolysis were about 2200 U/g,3%,80 minutes,and 50?.Orthogonal rotation combined experiment was used to further optimize the technological parameters of enzyme digestion,and the regression analysis model was established.According to the actual production conditions,the optimum technological conditions for the preparation of the antioxidant polypeptide of seabuckthorn seed meal by the combination of flavor enzyme and neutral enzyme were as follows: flavor enzyme:neutral enzyme=3:2(U:U),the pH was 7.0,the temperature was 52.5?,the amount of enzyme was2400U/g,the substrate concentration was 3% and the enzymolysis time was 80 min.Under this condition,the ABTS clearance rate of seabuckthorn seed meal diluted 100 times was 27.63% and the polypeptide concentration was about 21.62mg/mL.(3)To determine the decolorization process conditions of seabuckthorn polypeptides.Single factor experiments showed that the decolorization rate of powdered activated carbon was 53.44%,the decolorization rate of granular activated carbon was 24.59%,and the decolorization rate of diatomite was 8.63%.Finally,powdered activated carbon was used to decolorize seabuckthorn polypeptides.Chose the decolorization rate and peptide nitrogen loss rate as indicators,the optimum conditions determined by orthogonal experiment were:the powdered activated carbon usage was 2.5%,decolorization temperature 50 ?,the system pH was 3.0,decolorization time was 100 min.The antioxidant activity of decolorized seabuckthorn peptides and seabuckthorn polypeptides treated with optimal decolorization conditions was systematically tested in vitro for antioxidant activity.Decolorization treatment would cause some reduction in the antioxidant activity of seabuckthorn polypeptides,but it was within the acceptable range.The antioxidant activity of seabuckthorn polypeptides in different systems was not exactly the same,but it could be demonstrated that the seabuckthorn polypeptides prepared in this study have high antioxidant activity.