不同蛋白酶制备藜麦麸皮多肽及其活性研究

以藜麦麸皮为原料,利用高浓度乙醇粗提藜麦麸皮蛋白,并用4种蛋白酶(碱性、中性、复合、风味蛋白酶)酶解蛋白得到多肽。测定醇沉蛋白的分子质量分布、氨基酸组成以及4种蛋白酶的酶解能力和所得多肽的活性。结果表明,藜麦麸皮蛋白分子质量主要条带分布在22.8 k、39.1 k和52.7 kDa,其含有17种氨基酸,必需氨基酸/总氨基酸为35.17%,疏水性氨基酸/总氨基酸为28.48%。碱性蛋白酶对藜麦麸皮蛋白具有较高的水解能力,在120 min时达到13%,肽得率高达88.88%。风味蛋白酶酶解的多肽具有较好的α-葡萄糖苷酶抑制活性和Fe^2+螯合能力,分别为81.67%和89.03%;碱性蛋白酶酶解的多肽对酪氨酸酶的抑制率达到73.17%;中性蛋白酶酶解的多肽对DPPH自由基清除能力较强,为84.91%。研究结果表明藜麦多肽具有良好的生物活性,为藜麦麸皮进一步开发利用提供了一定的理论依据。

Activity of polypeptides from Chenopodium quinoa husks prepared with different proteases

Quinoa husks protein was extracted by high concentration ethanol from quinoa husks,and the protein was hydrolyzed by four kinds of proteases(alkaline,neutral,compound and flavor protease)to produce polypeptides.The molecular weight distribution and amino acid composition of quinoa protein,the enzymatic hydrolysis ability of four proteases and the activities of the polypeptides were determined.The results showed that quinoa husks protein with molecular weight of 22.8 kDa,39.1 kDa and 52.7 kDa contained 17 kinds of amino acids,and the ratios of essential amino acids and hydrophobic amino acids to total amino acids were 35.17%and 28.48%,respectively.The hydrolysis ability of alkaline protease for quinoa husks protein was the highest,with degree of hydrolysis reached 13%at 120 min,and the peptides yield was 88.88%.The peptides produced by flavor protease showed high α-glucosidase inhibitory activity and Fe^2+chelating ability,which were 81.67%and 89.03%respectively;the inhibition rate of alkaline protease produced peptides against tyrosinase was 73.17%,while neutral protease produced peptides had strong scavenging ability to DPPH free radicals,which was 84.91%.This study showed that quinoa peptides had good biological activities,which could provide a theoretical basis for further development and utilization of quinoa husks.