椰肉蛋白酶解及其产物的抗氧化活性研究

Enzymatic Hydrolysis of Coconut Protein and Antioxidant Activity of the Hydrolysates

摘要:

将新鲜椰肉粉碎脱脂，利用碱溶酸沉法制备椰肉蛋白。用Alcalase碱性蛋白酶、Neutrase中性蛋白酶、菠萝蛋白酶、Papain木瓜蛋白酶酶解椰肉蛋白，以DPPH自由基清除能力和水解度为指标对酶解过程进行分析，筛选出最适合制备抗氧化酶解物的酶为Alcalase碱性蛋白酶。然后采用单因素及多指标正交实验设计优化Alcalase碱性蛋白酶酶解条件，其中酶解温度和底物浓度对DPPH自由基清除率影响最大。优化后的制备参数为：酶解温度50 ℃，pH值10.5，加酶量14000 U/g，酶解时间7 h，底物浓度2%，该条件下水解液中蛋白含量为15.8 mg/mL，水解度和DPPH?清除率分别为29.16%和89.07%，椰肉蛋白酶解物显示出较强的抗氧化活性，接近同一浓度下谷胱甘肽的抗氧能力，比同浓度Vc的DPPH自由基清除率高3.33倍。

Abstract:

Coconut was crushed and defatted, giving coconut powder. Coconut protein was obtained by alkaline extraction and acid precipitation from coconut powder. Then coconut protein was hydrolyzed by four proteases (Alcalase, Neutrase, bromelin, Papain), among which Alcalase showed to be the optimal in terms of degree of hydrolysis and DPPH?scavenging rate of hydrolysates. By single factor and multi-index orthogonal design, hydrolysis conditions were optimized using degree of hydrolysis and DPPH?scavenging rate as the evaluating indexes. Hydrolysis temperature and substrate concentration showed the highest influence on DPPH?scavenging activity. The optimal conditions were substrate concentration 2% (m/V), enzyme concentration 14000 U/g, pH 10.5, temperature 50 ℃ and hydrolyzing time 7 h. Under these conditions, the protein content of hydrolysates, the scavenging rate on DPPH?and the degree of hydrolysis were 15.8 mg/mL, 89.07% and 29.16%, respectively. The antioxidant activity of coconut hydrolysates closed to that of the same concentration of glutathione, being 3.33 times higher than that of the same concentration of Vitamin C.