酶法提取地桃花多糖的工艺优化及其抗氧化活性

目的:研究纤维素酶提取地桃花多糖的最佳条件,并探讨其体外抗氧化活性。方法:以地桃花多糖得率为响应值,在单因素试验基础上,以液料比、酶解温度、酶解时间、酶添加量为试验因素,采用响应面法建立数学模型,筛选最佳提取工艺条件;并使用DPPH和·OH自由基清除能力体系检测地桃花多糖的抗氧化活性。结果:纤维素酶酶解提取地桃花多糖最佳条件为:酶添加量10.8 mg/mL、酶解时间72 min、液料比7:1 mL/g、酶解温度43℃、pH为5.0,在此条件下地桃花多糖得率为13.32%,与理论值13.37%相对误差小于5%。地桃花多糖具有较强的抗氧活性,对DPPH和·OH自由基清除的半数抑制浓度IC₅₀分别为1.082、3.202 mg/mL,但与维生素C比较,抗氧化活性较弱。结论:通过响应面法获得地桃花多糖纤维素酶酶法提取的最佳条件,该工艺条件方便可行,提取到的多糖具有较强的自由基清除能力。

Optimization of Enzymatic Extraction Process of Polysaccharide from Urena lobata L. and Its Antioxidant Activity

Objective:This study was aimed to optimize polysaccharides extraction from Urena lobata L. by cellulase enzymolysis approach and investigate its antioxidant activity. Methods:The mathematical model was established by response surface method(RSM)based on the results of single factor experiments,using polysaccharides extraction rate as response value and the ratio of water to material,cellulase concentration,extraction temperature and time as experimental factors,which was used to screen optimum polysaccharide extraction conditions from Urena lobata L.. Antioxidant activity of polysaccharides was studied by DPPH and ·OH free radical elimination method.Results:The optimum conditions obtained by RSM were as follows:The cellulase level was 10.8 mg/mL,extraction time duration was 72 min,the ratio of water to feedstock was 7:1 mL/g,extraction temperature was 43℃,the pH value was 5.0. Under the optimal conditions,there was a difference of less than 5% between predicted extraction rate 13.37% and experimental extraction rate 13.32%. IC₅₀ of DPPH and ·OH were 1.082 mg/mL and 3.202 mg/mL,respectively. Antioxidant activity of sample polysaccharides was weaker than those of vitamin C. Conclusion:The polysaccharide extraction process from Urena lobata L. by cellulase enzymolysis approach was obtained,which was convenient and feasible,and extracted polysaccharides had good free radical scavenging activity.