Preparation And Anti-alcoholism Activity In Vitro Of Black Bean Polypeptide

The protein content of black bean is the most all of the beans and its amino acid composition is better than soybean. Polypeptide has good characters and bioactivity, include high digestion and aborption, high stability, high solubility, the resistant to oxidant, lowered blood pressure and anti-alcoholism activity and so on. In this paper, the raw materials were the small black beans with green kernel from northeast China. The polypeptide was obtained after defatted, protein extraction, enzymatic hydrolysis. Black bean protein extraction conditions were optimized by orthogonal experiment, the protein digestion conditions was optimized by response surface design based on the single factor experiment and the effect was verified by valle-hoch method in vitro.(1) The extraction of proteinThe raw material basic components were tested. The results showed the black bean protein content was10%higher than soybean protein content. In order to improve the yield of protein and lower the impurity content of protein, pretreatment and degreasing of black bean was used before protein extraction. Using the protein yield as the index, the extraction conditions were optimized. The optimum conditions for protein extraction were extracting temperature50℃, solid-liquid ratio l:20g/mL, pH value9.0and extraction time2.5h.(2) The preparation of black bean polypeptideThis experiment adopted the step by step method to hydrolyze protein. The protein digestion conditions with alkaline protease were optimized with the degree of hydrolysis as index, these were enzymolysis temperature50℃, enzymolysis time4h, enzymolysis solid-liquid ratio1:15g/mL, enzyme quantity5000U/g and enzyme solution pH value9.0. In this point the highest enzymic hydrolysis degree was achieved. The trypsin was used on this basis to achieve the hydrolyzate which had the highest activation of alcohol dehydrogenase activity in vitro.Based on this, then use trypsin to improve the degree of hydrolysis and black beans polypeptide yield.(3) The sober activity of black bean polypeptide in vitroPolypeptides generally have sober function. In order to improve the hangover effect of the polypeptide, the black bean peptides were isolated by molecular weight and the sober activities in vitro were measured. The amino acid composition was analyzed. The results showed the sober activity with polypeptide between500Da to2000Da was optimal. The amino acid analysis indicated its high sober activity was related with high content of leucine and alanine.