不同蛋白酶对小麦蛋白酶解物抗氧化活性的影响

摘要

小麦蛋白是小麦淀粉加工的副产物,酶解是提高小麦蛋白溶解性和功能性的有效方式,而酶解用酶种类可能对酶解产物的功能性如抗氧化活性有一定影响.采用碱性蛋白酶、中性蛋白酶、胃蛋白酶、风味蛋白酶、胰蛋白酶、木瓜蛋白酶6种常用的蛋白酶分别对小麦蛋白进行酶解,并对酶解4h后酶解物的多肽得率、分子质量分布、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除率、超氧阴离子自由基(O2-·)清除率、羟自由基(·OH)清除率等反映水解程度和抗氧化能力的主要指标进行评价.结果表明,风味蛋白酶酶解物中多肽得率最高,达91.44％,且分子质量小于3 000 D的多肽含量达76.9％;酶解物质量浓度为3 mg/mL时,木瓜蛋白酶酶解物对DPPH自由基清除作用最好,清除率为65.12％ (P＜0.01),其次是风味蛋白酶(58.43％)和碱性蛋白酶(55.29％);碱性蛋白酶酶解物对O2-·清除率效果最好,清除率为58.68％ (P＜0.01),其次是风味蛋白酶(49.25％);碱性蛋白酶和木瓜蛋白酶酶解物对·OH清除效果最佳,清除率分别为59.23％和58.16％.结果说明,蛋白酶种类对小麦蛋白酶解物抗氧化活性影响显著,风味蛋白酶对提高蛋白水解程度和生成小分子质量多肽的作用明显,而碱性蛋白酶、木瓜蛋白酶和风味蛋白酶对提高酶解产物抗氧化活性效果较好.%Wheat gluten is a main by-product of wheat starch processing.Enzymatic hydrolysis is an effective way of improving the solubility and functionality of wheat gluten;however,protease type may influence the functionalities of wheat gluten hydrolysates such as antioxidant activities.Six frequently used proteases including Alcalase,Neutrase,Pepsin,Flavourzyme,Pancreatin and Papain were used for the hydrolysis of wheat gluten,and the degree of hydrolysis and antioxidant capacity of four-hour hydrolysates were evaluated in terms of polypeptide yield,molecular weight distribution,1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity,superoxide radical anion (O2-·) scavenging activity,and hydroxyl radical (·OH) scavenging activity.The results showed that Flavourzyme hydrolysate exhibited the highest polypeptide yield (91.44％),containing up to 76.9％ polypeptide with a molecular weight of less than 3 000 D.Papain hydrolysate at a concentration of 3 mg/mL exhibited the best DPPH radical scavenging activity (65.12％ scavenging percentage,P ＜ 0.01),followed by Flavonrzyme hydrolysate (58.43％) and Alcalase hydrolysate (55.29％).Alcalase hydrolysate exhibited the best superoxide anion radical scavenging activity (58.68％ scavenging percentage,P ＜ 0.01),followed by Flavourzyme hydrolysis (49.25％).Alcalase and Papain hydrolysates exhibited the best hydroxyl radical scavenging activity (scavenging percentages of 59.23％ and 58.16％,respectively).Therefore,protease type had a notable effect on antioxidant activities of wheat gluten hydrolysates.In addition,Flavourzyme hydrolysis gave a significant improvement in the degree of hydrolysis and the formation of small polypeptides;moreover,Alcalase,Papain and Flavourzyme resulted in improved antioxidant activities of hydrolysates.