响应面法优化龙须菜蛋白酶解工艺及酶解液的抗氧化活性

Optimization for enzymatic hydrolysis of Gracilaria lemaneiformis protein and antioxidant activity of its hydrolysate

为获得高抗氧化活性的龙须菜蛋白酶酶解液,运用响应面(RSM)分析方法对龙须菜蛋白酶解工艺条件进行优化。经单酶筛选,在单因素实验基础上,以亚铁离子螯合率和DPPH自由基清除率为主要指标,水解度为辅助指标,研究酶解时间、p H、酶解温度、底物质量浓度、加酶量对龙须菜蛋白酶解液抗氧化活性和水解度的影响。结果表明:在所选的5种蛋白酶中,复合蛋白酶是龙须菜蛋白酶解的最适用酶;酶解液抗氧化活性的最优酶解条件为酶解时间8.1 h、酶解温度50.1℃、p H7.0、底物浓度10 g/L、加酶量0.1%(0.15 AU/g)。在此条件下,酶解液的亚铁离子螯合率为74.61%,DPPH自由基清除率为47.66%,水解度为17.58%。对比常用抗氧化剂,酶解液在亚铁离子螯合能力方面显著高于0.01%维生素C和0.01%BHA(p<0.05),而在DPPH自由基清除能力和还原能力方面,酶解液低于0.01%维生素C和0.01%BHA(p<0.05)。优化后的龙须菜蛋白酶酶解液具有一定的抗氧化活性。

Response surface methodology （RSM）was employed to optimize the process conditions for the enzymatic hydrolysis of Gracilaria lemaneiformis protein. After the single enzyme screening experiments, the ferrous ion- chelating and DPPH free radical scavenging abilities as the main index, the degree of hydrolysis as the auxiliary index, the effects of hydrolysis time, pH, hydrolysis temperature, concentration of substrate and enzyme dose on the degree of hydrolysis and the antioxidant activity of hydrolysates were investigated based on the single factor experiments.The results showed that protamex was the best enzyme for the enzymatic hydrolysis of Gracilaria lemaneiformis protein.The optimal conditions for the ferrous ion-chelating ability and the scavenging activity on DPPH free radical were as follows：hydrolysis time of 8.1 h, pH7.0, temperature of 50.1 ~C, substrate concentrate of 10 g/L, and enzyme dose of 0.1%.Under these conditions, the ferrous ion-chelating ability of hydrolysate was up to 74.61% , significantly higher than that of 0.01% ascorbic acid and 0.01% BHA （p 〈 0.05 ）.The scavenging ability of DPPH free radical was 47.66% ,and the degree of hydrolysis was 17.58% ,lower than that of 0.01% ascorbic acid and 0.01% BHA （p 〈 0.05）. These results suggested that the protein hydrolysates possess excellent antioxidant activity.