双酶水解玉米醇溶蛋白制备抗氧化肽的工艺优化
Optimization of dual- enzymatic preparation of antioxidant peptides from zein
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摘要: 为了制备抗氧化活性肽,利用Alcalase碱性蛋白酶和中性蛋白酶分步酶解玉米醇溶蛋白。在单因素的基础上,以1.1-二苯基苦基苯肼(DPPH·)自由基清除率、羟基自由基清除率和水解度(DH)为响应值,采用响应面(RSM)中心组合实验,选取Alcalase碱性蛋白酶加酶量、中性蛋白酶与Alcalase碱性蛋白酶活力之比、底物浓度为自变量,探讨最佳酶解工艺条件。采用Design-Expert软件,通过响应面优化确定修正后各因素的最佳工艺条件为:Alcalase碱性蛋白酶加酶量12880 U/(g底物)、中性蛋白酶与Alcalase碱性蛋白酶活力之比为1∶4,底物浓度为3.4%。在此修正条件下,DPPH·自由基清除率为42.98%,水解度为32.18%,与预测值的相对误差为1.04%。浓度为20 mg/m L时,玉米醇溶蛋白的DPPH·自由基清除率和羟基自由基清除率分别为同浓度VC的85.8%和67.0%。Abstract: In order to prepare antioxidative peptides, zein powder was subjected to stepwise hydrolysis initially with Neutral protease followed by Alcalase. DPPH· cleavage activity and degree of hydrolysis were used to evaluate antioxidative activity of hydrolysates. Furthermore, response surface methodology ( RSM) was employed to optimize hydrolysis conditions, including Alcalase dosage, Neutral protease / Alcalase, and substrate concentration.The modified optimum conditions obtained were as follows: Alcalase dosage of 12880 U / g, Neutral protease /Alcalase of 1 ∶ 4, and substrate concentration of 3.4%. Under the modified condition, DPPH· radical scavenging activity of 42.98% and DH of 32.18% were obtained, and the relative error of forecast value was 1.04%. When the concentration was 20 mg / m L, the DPPH·radical scavenging activity and the hydroxyl radical rate were 85.8% and67% of VC, respectively.