响应面法优化制备南瓜籽抗氧化肽的工艺

以南瓜籽分离蛋白为原料，采用酸性蛋白酶酶解制备南瓜籽抗氧化肽。选用加酶量、酶解温度、pH值、底物质量浓度、酶解时间作为研究对象，以酶解液对DPPH自由基的清除率为评价指标，在单因素试验的基础上，运用Plackett-Burman筛选试验确定显著因素，然后通过三因素三水平的Box-Behnken响应面分析法优化制备南瓜籽抗氧化肽的酶解工艺条件。结果表明：酸性蛋白酶酶解南瓜籽蛋白质的最佳工艺条件为：酶解温度50℃、pH2.5、酶解时间5h、底物质量浓度0.05g/mL、加酶量6000U/g pro，在此条件下，DPPH自由基清除率可达到92.82%。

Optimization of Preparation Process for Antioxidant Peptides from Pumpkin Seed by Response Surface Methodology

Pumpkin seed protein isolate was hydrolyzed by acidic protease to prepare antioxidant peptides. One-factor-at-a-time experiments were done to explore the effects of enzyme concentration, pH, temperature, substrate concentration and hydrolysis time on the scavenging activity of pumpkin seed hydrolysate against DPPH free radicals. Enzyme concentration, susbstrate concentration and hydrolysis time were identified as main affecting parameters and optimized using response surface analysis based on a three-variable, three-level Box-Behnken design. The optimal hydrolysis conditions were determined as hydrolysis temperature of 50 ℃, hydrolysis pH of 2.5, enzyme concentration of 6000 U/g, substrate concentration of 0.05 g/mL and hydrolysis time of 5 h. Under these conditions, the scavenging activity of DPPH free radicals was up to 92.82%.