小米多肽的制备及其抗氧化功能研究

采用碱性蛋白酶Alcalase水解小米蛋白，以二苯代苦味肼基(DPPH)自由基清除率为指标，通过单因素试验和正交试验确定小米多肽最佳制备条件，用硝基四氮唑蓝(NBT)还原试验、脱氧核糖法检测其对超氧阴离子自由基(O2·)和羟自由基(·OH)的清除能力，分光光度法测定小鼠红细胞溶血和肝线粒体MDA生成量。结果表明：碱性蛋白酶Alcalase制备小米多肽的最佳酶解条件为pH8.5、E]/S]5%、温度40℃、时间3.5h、对DPPH自由基、O2·和·OH的清除率分别为68.93%、40.06%和48.63%，并具有明显抑制氧化溶血现象和·OH诱导线粒体氧化损伤的功能，表明小米多肽具有较强的抗氧化功能。

Preparation and Antioxidation in vitro of Millet Peptides

Millet peptides were prepared by means of alcalase hydrolysis, and the optimum enzymatic hydrolysis parameters were determined by single-factor test and orthogonal design. Then their scavenging activity to surperoxide anion radical and hydroxyl radical were detected by nitroblue tetrazolium (NBT) test and deoxyribose method, and the extent of erythrocatalysis and the formation of malondialdehyde (MDA) in liver mitochondria were detected by spectrophotometric method. The results showed that the optimum preparation conditions for millet peptides are hydrolysis with 5% of concentration ratio of enzyme to substrate at pH 8.5 and 40 ℃ for 3.5 h. The scavenging activity of millet peptides to DPPH radical, superoxide anion radical (O2·) and hydroxyl radical (·OH) are 68.93%, 40.06% and 48.63%, respectively. Moreover, the millet peptides can effectively inhibit the hemolysis of red blood cells and the damage of mitochondria. Therefore, they have significant antioxidation.