响应面法优化金果榄多糖提取工艺及抗氧化活性研究

Optimization of Extraction Process of Polysaccharide from Tinosporae Radix by Response Surface Method and Study on Its Antioxidant Activity

目的研究复合酶提取金果榄多糖的最佳条件,并探讨其体外抗氧化活性。方法复合酶种类及配比为纤维素酶∶果胶酶∶木瓜蛋白酶=1∶1∶1,液料比固定为20 mL/g,以金果榄多糖得率为响应值,在单因素试验基础上,以酶解pH值、酶解时间、复合酶添加量、酶解温度为自变量,采用响应面法建立数学模型,筛选最佳提取工艺;采用DPPH自由基、羟自由基(·OH)、超氧阴离子自由基(O_2^-·)清除能力体系评价金果榄多糖体外抗氧化活性。结果金果榄多糖最佳提取条件为:酶解pH值5.1,酶解时间56 min,复合酶添加量2.0%,酶解温度52℃。在此条件下多糖得率为14.03%,与理论值14.12%的相对误差<5%。酶解温度对多糖得率影响最显著,酶解时间、酶解pH值次之,酶添加量影响最小。金果榄多糖对DPPH、·OH、O2_^-·清除的半数抑制浓度分别为1.358、0.927、1.096 mg/mL,与维生素C比较,抗氧化活性较弱。结论本研究优选的金果榄多糖复合酶法提取工艺方便可行,酶解得到的多糖具有较强的体外抗氧化活性。

Objective To optimize extraction process for polysaccharides from Tinosporae Radix through compound enzymatic hydrolysis;To investigate its antioxidant activity in vitro. Methods The types and ratios of the complex enzymes were cellulase: pectinase: papain = 1:1:1. The liquid-to-solid ratio was fixed at 20 mL/g, and the yield of the polysaccharide from Tinosporae Radix was the response value. On the basis of single factor experiment, the enzymatic hydrolysis p H value, enzymatic hydrolysis time, complex enzyme addition amount and enzymatic hydrolysis temperature were used as independent variables, and the response surface method was used to establish a mathematical model to screen the optimal extraction process. DPPH, ·OH, O2-· free radical scavenging system was used to evaluate in vitro antioxidant activity of polysaccharide from Tinosporae Radix. Results The optimum extraction conditions were as follows: enzymatic hydrolysis p H value was 5.1;enzymolysis extraction time duration was 56 min;the compound enzyme concentration was 2.0%;enzymolysis extraction temperature was 52 ℃. Under the optimal conditions, there was a difference of less than 5% between predicted extraction rate 14.12% and experimental extraction rate 14.03%. The polysaccharide yield was most significantly affected by enzymolysis extraction temperature, followed by enzymolysis extraction time duration, enzymolysis p H value and compound enzyme concentration. The half-inhibitory concentration of polysaccharide from Tinosporae Radix for DPPH, ·OH, and O2-· free radical scavenging was 1.358, 0.927, and 1.096 mg/mL, respectively. Antioxidant activity of sample polysaccharides was weaker than those of vitamin C. Conclusion Extraction process for polysaccharides from Tinosporae Radix through compound enzymatic hydrolysis is convenient and feasible, and extracted polysaccharides have good antioxidant activity in vitro.