酶法水解牦牛皮蛋白制备抗氧化肽工艺的优化

以牦牛皮为原料，用碱性蛋白酶水解牦牛皮蛋白制备抗氧化肽。以水解度和牦牛皮蛋白水解物对DPPH自由基清除率的IC₅₀值为评价指标，在单因素实验的基础上，结合响应面（Box-Behnken）试验设计筛选出牦牛皮抗氧化肽的最佳制备工艺。结果表明，最佳制备工艺为:水解温度51 ℃，酶用量10890 U/g，水解时间10.6 h，pH8.5，底物浓度5%，此时水解度为41.39%±0.69%，牦牛皮抗氧化肽清除DPPH·、ABTS+·、·OH的IC₅₀值分别为2.884、2.110、2.523 mg/mL。综上，该制备工艺下的牦牛皮抗氧化肽对自由基有良好的清除能力，且有较强的还原能力，说明牦牛皮抗氧化肽有望作为天然抗氧化剂得到开发利用。

Process of the Preparation of Antioxidant Peptides by Enzymatic Hydrolysis of Yak Hide Protein

Antioxidant peptide were produced from the yak hide protein through alkaline protease hydrolysis. Based on a single-factor experiment and the Box-Behnken response surface design, the best antioxidant peptide were determined using the yak hide protein hydrolysis degree and the IC₅₀ of the yak hide protein hydrolysate scavenging activity against DPPH free radical as the evaluation indices. Results showed that, the best hydrolysis process was as follows: Temperature 51 ℃, enzyme dosage 10890 U/g, hydrolysis time 10.6 h, pH8.5, substrate concentration 5%. Per the above conditions, the degree of hydrolysis was 41.39%±0.69% and the IC₅₀ values of yak hide antioxidant peptides on DPPH·, ABTS+· and ·OH were 2.884, 2.110, 2.523 mg/mL, respectively. In conclusion, the antioxidant peptides of yak skin under the preparation process had good scavenging capacity for free radicals and strong reducing capacity, which indicated that the antioxidant peptides of yak skin would be expected to be developed and utilized as natural antioxidants.