Enzymatic Preparation And Research On The Antibacterial Activity Of Tartary Buckwheat Protein Hydrolysates

Buckwheat is a kind of edible and medicinal product, it widely used for its high nutritional value and varieties of physiological functions,such as antioxidant,anticancer, lowering blood lipid and blood pressure in life. As an an important biologically active substances in buckwheat,buckwheat protein has broad prospects for market development and research value owing to its natural antibacterial and antioxidant capacity.In this paper, we used Tartary buckwheat from Shanxi Province as raw materials. The process route about the isolation and purification of buckwheat protein were established after several of pretreatments. At first, we focused on the preparation of buckwheat crude protein and buckwheat protein hydrolysates,which to further study the antibacterial activity and antioxidant capacity in vitro of buckwheat.The main contents as follows:1. we extracted the tartary buckwheat water-soluble protein by saturated ammonium sulfate method and further purified the protein extracts by DEAE-Fast-Flow ion exchange and Sephadex G-75 gel filtration chromatography. At last, we used vitro digestion(1h pepsin followed by 2h pancreatin) and Sephadex G-25 gel filtration chromatography to obtain four kinds of buckwheat protein hydrolysates,named Pep1、Pep2、Pep3、Pep4.2. The antimicrobial activity of buckwheat protein crude extracts tested by the method of diffusion filter paper,and we useed four strains as the mian indicator bacteria to complete the antimicrobial experiment.The results concluded that : In addition to E. coli, the buckwheat protein crude extracts can all inhibited the growth of other tested bacteria(Staphylococcus aureus).In a word, the inhibitory effect to gram-positive bacteria(G+)was better than gram-negative bacteria(G-).3. We chose four bacteria(Escherichia coli、Salmonella Lignieres、Staphylococcus aureus and Enterobacter sakazakii) for antibacterial test,The minimum inhibitory concentration(MIC) of buckwheat protein hydrolysates were used the tube dilution method. The results showed that the inhibitory effect by Staphylococcus aureus was the strongest.The minimum inhibition concentration to buckwheat peptitde 3 and peptitde 4 were 0.375mg/ml and 0.093 mg/ml.4. We used three antioxidant experiments(DPPH, ABTS, FRAP) to study theantioxidant effects of buckwheat crude protein on the condition of different concentrations in vitro.The results showed that on the same conditions, the antioxidation ability of buckwheat crude protein increased with the rise of protein concentrations,but slightly lower than the control(VC and BHT). We chose DPPH(radical scavenging experiment) to evaluate the antioxidant activities of buckwheat protein hydrolysates.Above all,the clearance rate of Tartary buckwheat protein hydrolysates were significantly improved compared with buckwheat crude protein,and also the clearance rate added to 80%. It revealed that Tartary buckwheat protein after enzymatic hydrolysis have stronger antioxidant activity.