Study On Antioxidative Peptide Of Peanut Meal

Peanut meal, which is mainly applied in feed, sometimes even discarded as waste,is a by-product when peanut oil is extracted.Simultaneously.As natural antioxidants,antioxidant peptides have attracted increasing interests because of their safety and good antioxidative properties in recent years.Therefore, making full use of Peanut meal to prepare antioxidant peptide is an important research topic.It represents a significant value.In this paper,the optimum conditions for producing the antioxidative peptide of peanut meal,using liquid state fermention by Bacillus subtilis20029 screened,were determined by response surface methodology as follows:temperature30℃,pH value 8,the period of fermentation 49.5h.Under the optimal condition,the DPPH radical-scavenging activity of fermentative product reached 63.28%.Under the different fermentation time,the correlation of DPPH radical (DPPH?) scavenging activity and the content of peptide was studied,there were strong relativities about DPPH radical (DPPH?) scavenging activity and the content of peptide,P=0.0010.Using ultrafiltration to Peanut meal,the result showed it was a good method of separation. After ultrafiltration,there was no considerable change of the antioxidative activity of filtrate.Peptide was desalted by DA201-C (macroporous adsorption resin).The results indicated that the adsorption of peptide belonged to rapid equilibrium adsorption.The breakthrough point was affected by the flow rate,concentration.The result of the research of thermal dynamics showed that the adsorption of peptides was in accordance with Langmuir equation,the correlation coefficient were all more than 0.98.The primary purification was carried out by ethanol with different concentration (25 %～100 %) according to their hydrophobic property,the fraction eluted by ethanol with 75% concentration showed the best antioxidant activity.the amino acid composition and molecular weight of each fraction were different with each other.PMFH-75 was separated by Gel filtration chromatography and RP-HPLC, PMFH-75 was separated into four components by Gel filtration chromatography,The DPPH radical (DPPH?) scavenging activity of the F3 was significantly higher than the other three components. Meanwhile,the composition and structure of F3 were analyzed.Finally,the ingredients of residue after fermentation were analyzed.In respect of the composition of amino acids,comparing to raw materials,the results showed that the content of Met increased,Arg decreased,but the nutritive value of protein was improved.