苦竹笋多糖提取工艺优化及其抗氧化活性研究

Optimization of Extraction Technology and Antioxidant Activity of Polysaccharides from the Bamboo Shoots of Pleioblastus Amarus

优化苦竹笋中多糖的提取工艺,并对其结构和抗氧化活性进行研究。以苦竹笋为研究对象,在单因素的基础上,通过响应面试验优化苦竹笋多糖的提取条件,应用紫外光谱、傅里叶红外光谱和扫描电镜对多糖的纯度、官能团和外貌进行分析,以DPPH自由基、ABTS自由基、.OH自由基清除能力和总还原力为指标评价苦竹笋多糖的抗氧化活性。结果表明,苦竹笋多糖最佳提取工艺为:酶用量4.1%、酶解时间85 min、酶解温度49℃。在此条件下苦竹笋多糖提取率为(2.66±0.08)%,与预测值基本相符。苦竹笋多糖几乎不含蛋白质和核酸,是一种整体呈片状,表面有不规则纹路,结构紧密,具有糖醛酸的吡喃酸性多糖。苦竹笋多糖对DPPH自由基、ABTS自由基、.OH自由基的半数抑制浓度(IC_(50))分别为2.52、1.19、1.12 mg/mL,当浓度为5 mg/mL时,其总还原能力与维生素C质量浓度为0.5 mg/mL时的还原能力基本相等,具有良好的抗氧化活性。该结果为苦竹笋多糖进一步的化学结构和功能研究提供了试验基础与理论依据。

The purpose is to optimize the extraction technology of polysaccharides from the bamboo shoots of Pleioblastus amarus Keng f.and to study its structure and antioxidant activity.Based on the results of the single experiments,the response surface method was applied to optimize the extraction conditions of polysaccharides from bamboo shoots.The purity,functional groups and external structure of the polysaccharides were analyzed by ultraviolet spectrum,fourier transform infrared spectroscopy and scanning electron microscopy.The antioxidant activity of polysaccharides from the bamboo shoots was evaluated by measuring DPPH free radical,ABTS free radical,OH free radical scavenging ability and total reducing power.The results showed that the optimal extraction conditions were as follows:enzyme dosage of 4.1%,enzyme time of 85 min and enzyme temperature of 49.Under these conditions,the extraction yield of polysaccharide from bamboo shoots was(2.66±0.08)%,which were basically consistent with the predicted value.The obtained bamboo shoots polysaccharide was acid polysaccharide of pyranoid with uronic acid,and contains almost no protein and nucleic acid,and the whole shape is flake,the surface has irregular lines,the structure is compact.The half inhibitory concentration(IC_(50))of the polysaccharides on DPPH free radical,ABTS free radical and-OH free radical were 2.52 mg/mL,1.19 mg/mL and 1.12 mg/mL respectively,and when the concentration was 5 mg/mL,the total reducing power was basically equal to Vitamin C with concentration of 0.5 mg/mL,and it proved that the polysaccharides have good antioxidant activity.The results provide a theoretical basis for further study on the structure determination and the function of the polysaccharides.