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以水解度为指标,对碱性蛋白酶酶解魔芋飞粉蛋白条件进行优化;测定不同酶解阶段及不同分子质量魔芋多肽的ACE抑制活性,筛选具有高ACE抑制活性的降血压多肽。结果表明:在底物质量分数2.25%,加酶量3 500 U/(g底物),温度55℃,pH 7.82的条件下酶解270 min,酶解产物的ACE抑制率达到最大值94.6%,此时水解度9.97%,多肽得率12.26%;酶解液经浓缩、干燥得到的魔芋多肽粉呈淡黄色,多肽含量52.62%,粗蛋白含量62.30%;用葡聚糖凝胶G-25和葡聚糖凝胶G-15串联柱分离得到2个具有高ACE抑制活性的多肽组分,其分子质量分别为1 500和1 000 Da,半抑制质量浓度分别为0.12 mg/mL和0.088 mg/mL。
The degree of hydrolysis was used as an index to optimize the enzymatic hydrolysis of konjac powder by alkaline protease. The ACE inhibitory activity of konjac peptides at different enzymatic hydrolysis stages and molecular weights was determined, and the antihypertensive peptides with high ACE inhibitory activity were screened. The results showed that the ACE inhibitory rate reached the maximum of 94.6% under the conditions of 2.25% substrate concentration, 3 500 U / (g substrate), temperature 55 ℃, pH 7.82 for 270 min, , The degree of hydrolysis is 9.97%, the yield of polypeptide is 12.26%; the konjac polypeptide powder obtained by concentrating and drying in the hydrolyzate is light yellow, the polypeptide content is 52.62% and the crude protein content is 62.30%; using dextran gel G-25 Two polypeptide components with high ACE inhibitory activity were isolated from Sephadex G-15 column, and their molecular weights were 1 500 and 1 000 Da respectively. The half-inhibitory concentrations were 0.12 mg / mL and 0.088 mg, respectively / mL.