基于Plackett-Burman设计和响应面法优化羊肝抗氧化肽的制备工艺

以羊肝为原料，分别测定5种蛋白酶酶切羊肝所得的酶解液的羟基自由基清除率和肽得率。结果表明，风味蛋白酶羟自由基清除率（84.50%）和肽得率（22.49%）最好。在单因素试验基础上，以羟基自由基清除率为评价指标，采用响应面法优化最佳酶解条件。结果表明，羊肝抗氧化肽制备的最佳酶解条件为料液比1∶3（g∶mL）、加酶量2 400 U/g、酶解温度50 ℃、pH7.50、酶解时间2.8 h。在此优化条件下，测得实际羟自由基清除率为93.70%，与模型理论值相接近。羊肝酶解产物中总氨基酸含量为57.23 g/100 g，其中疏水性氨基酸和必需氨基酸占总氨基酸含量分别为46.47%和41.63%，表明以风味蛋白酶酶解羊肝产物具有较高的抗氧化活性和营养价值。

Optimization of preparation technology of antioxidant peptides from sheep liver by Plackett-Burman design and response surface methodology

Using the sheep liver as raw material, the hydroxyl free radical scavenging rate and peptide yield of enzymatic hydrolysis solution was obtained from sheep liver, the activity of five protease were determined. The enzyme screening results showed that hydroxyl free radical scavenging rate (84.50%) and peptide yield (22.49%) of enzymatic hydrolysis solution by flavor protease were the optimal. On the basis of single factor experiments, with hydroxyl free radical scavenging rate as evaluation index, the optimum enzymolysis conditions were optimized by response surface method. The results showed that the optimum hydrolytic conditions of sheep liver antioxidant peptides preparation were material-liquid ratio 1∶3 (g∶ml), enzyme addition 2 400 U/g, enzymolysis temperature 50 ℃, pH 7.50 and enzymolysis time 2.8 h. Under the conditions, the actual hydroxyl free radical scavenging rate was 93.70%, which was close to the model theoretical value. The total amino acid content in the sheep liver enzymolysis products was 57.23 g/100 g, in which the contents of hydrophobic amino acid and essential amino acid were 46.47% and 41.63%, respectively. It indicated that sheep liver enzymolysis products by flavor protease had high antioxidant activity and nutritional value.