泥鳅蛋白抗氧化肽的Plastein反应修饰研究

采用中性蛋白酶水解泥鳅蛋白制备抗氧化肽,以DPPH自由基清除能力为指标,用木瓜白酶对泥鳅蛋白抗氧化肽进行Plastein反应修饰研究。通过单因素试验研究了外源氨基酸种类、pH值、时间、E/S、温度和外源氨基酸的添加量对泥鳅蛋白抗氧化肽Plastein反应修饰的影响,在此基础上采用响应面法对泥鳅蛋白抗氧化肽Plastein反应修饰工艺进行了优化。结果表明,泥鳅蛋白抗氧化肽Plastein反应修饰的最佳条件为:底物浓度40%、组氨酸添加量为0.5 mmol·g^-1、E/S为1 782.49 U·g^-1 、pH值9.0、温度35 ℃、时间3 h,此条件下制备的Plastein反应修饰产物的抗氧化活性是修饰前的1.99倍,其对DPPH自由基的清除率为(77.98±0.08)%。

Modification of antioxidant peptide from loach protein by Plastein reaction

Loach protein was hydrolyzed by neutrase to prepare antioxidant peptide in this study. Plastein reaction was used to modify loach protein hydrolysates for enhancing the scavenging ability of DPPH free radical of peptides by papain. The influences of the types of added amino acids, the extrinsic glycine dose, the substrate/enzyme ratio, pH value, temperature and hydrolysis time on scavenging ability of DPPH free radical of the Plastein reaction modification of loach protein hydrolysates were investigated by using single factor analysis method. On this basis, the optimal technology conditions for Plastein reaction modification of antioxidant peptide from loach protein was obtained by response surface methodology. Results showed that the optimal conditions for Plastein reaction modification of antioxidant peptide from loach protein were as followings: substrate concentration at 40%, extrinsic dose of histidine at 0.5 mmol·g^-1, E/S ratio at 1 782.49 U·g^-1, pH at 9.0, temperature at 35 ℃, and reaction time at 3.0 h. The antioxidant activity of modified antioxidant peptide by Plastein reaction was about 1.99 times of original antioxidant peptide under this condition, and the scavenging ability of DPPH free radical was (77.98±0.08)%.