抗氧化紫球藻胞外多糖酶解物制备工艺优化

Optimization on the enzymatic preparation of extracellular polysaccharide from Porphyridium creuntum with antioxidant activities in vitro

以紫球藻胞外多糖为原料,·OH清除率为评价指标,依据单因素试验,利用Box-Behnken中心组合试验和响应面分析法,对EPS粗品的酶解工艺进行优化,并评价EPS粗品酶解前后的抗氧化活性。结果表明,EPS粗品酶解最佳工艺参数为:酶解时间6.3h,酶解pH 8.0,酶解温度63℃,酶添加量(酶/底物)2.7 U/mg,酶解液对·OH的清除率达到(70.64±0.38)%;优化酶解条件下酶解产物的抗氧化活性显著提高,酶解产物对·OH、DPPH·、ABTS^+·和O_2^-·的半数清除浓度(IC_(50))分别为(1.67±0.58),(1.08±0.01),(0.64±0.01),(4.16±0.01)mg/mL。

The optimum enzymatic conditions of extracellular polysaccharide of Porphyridium creuntum（EPS）were investigated in this research.Based on the results of single factor experiment,by using the Box-Behnken response surface method array design,the optimum conditions for hydrolyzing EPS to obtain antioxidant hydrolysates with the highest hydroxyl radical scavenging activity were as follows：enzymolysis reaction time 6.3 h,enzymolysis reaction pH 8.0,enzymolysis temperature 63 ℃,and enzyme-to-substrate ratio 2.7 U/mg.Under the conditions,the scavenging rate of hydroxyl radical was 70.64%.Subsequently,the antioxidant activity of the enzymatic hydrolysates were determined in vitro.The results showed that the enzymatic hydrolysates had good scavenging abilities on ·OH,DPPH·,ABTS^＋·and O_2^-·,the half-scavenging concentration values of the crude hydrolysates against·OH,DPPH·,ABTS^＋· and O2^-· radicals were（1.67±0.58）mg/mL,（1.08±0.01）mg/mL,（0.64±0.01）mg/mL and（4.16±0.01）mg/mL respectively.