中性蛋白酶水解藏羊血清蛋白制备抗氧化肽的研究

Preparation of antioxidant peptide by hydrolization of tibitan sheep serum protein by neutral protease

采用中性蛋白酶对藏羊血清蛋白进行水解,以水解度为评价指标,研究水解温度、时间、p H、酶与底物浓度比([E]/[S])对水解度的影响。在单因素的基础上进行响应面实验,对中性蛋白酶水解藏羊血清蛋白的工艺条件进行优化。结果表明:当[E]/[S]为2400 U/g,温度为50℃,水解时间为5.5 h,水解p H为6.8是最优水解条件,水解度可达到(15.44±0.395)%。通过研究水解产物DPPH自由基清除能力、羟自由基(·OH)的清除能力以及超氧阴离子(O-2·)的清除能力来分析其抗氧化活性。结果表明多肽的抗氧化活性和多肽的浓度在一定的浓度范围内有良好的量效关系,随着多肽浓度的增大,其抗氧化活性增加,其对DPPH自由基、羟自由基和超氧阴离子的半抑制浓度(IC50)分别为:6.035、3.555和2.872 mg/m L。

Tibitan sheep serum protein was hydrolyzed by neutral protease, the influences of the temperature, hydrolysis time,pH value and the substrate/enzyme ratio on the degree of hydrolysis of Sheep serum protein were investigated.On the basis of single factor tests and response surface methodology,the optimal working parameters were worked out and tested.The optimum hydrolysis parameters were as follows-when the amount of enzyme was 2400 U/g, hydrolyzing 5.5 hours at temperature 50 ℃ under pH6.8, and the degree of hydrolysis was 15.44 ± 0.395% under the optimum conditions.The antioxidant activities of the hydrolysate was measured by the inhibiting effect on the scavenging ability of 1, 1- diphenyl-2-pycrylhydrazyl （ DPPH ）, hydroxyl radical and superoxide radical.The antioxidant activities increased with increasing concentrations of test samples.The peptides exhibited high scavenging ability of DPPH, hydroxyl radical and superoxide radical with an IC50 value of 6.035,3.555 and 2.872 mg/mL respectively.