梁平柚柚皮多糖的提取、结构解析及抗氧化能力研究

Optimization of extraction technology,structure analysis and antioxidant activity of polysaccharides from Liangping pomelo peel

为提高梁平柚柚皮的综合利用率,采用单因素实验与响应面实验优化酶法辅助提取梁平柚柚皮多糖的工艺参数。采用液相色谱-质谱联用、紫外光谱、红外光谱和扫描电镜对梁平柚柚皮多糖的结构进行表征,并采用体外抗氧化实验考察其抗氧化活性。结果表明,酶法辅助提取梁平柚柚皮多糖的最佳工艺参数为:液料比25∶1(mL∶g),提取pH 6.0,酶解时间90 min,酶解温度50℃。此条件下,梁平柚柚皮多糖提取率为5.46%。梁平柚柚皮多糖主要由核糖(1.18%)、葡萄糖醛酸(1.32%)、甘露糖(4.26%)、鼠李糖(4.72%)、葡萄糖(11.46%)、半乳糖(21.48%)、半乳糖醛酸(23.67%)和阿拉伯糖(31.90%)等单糖组成;紫外光谱与红外光谱分析表明,梁平柚柚皮多糖不含蛋白质与核酸,是一种具有吡喃糖环并由β-糖苷键连接的酸性多糖;扫描电镜结果表明,梁平柚柚皮多糖呈片状,并具有纤维状的结构。此外,抗氧化结果表明,在一定浓度范围内,梁平柚柚皮多糖的体外抗氧化活性具有剂量效应关系。其DPPH自由基清除率、·OH清除率和·O_(2)^(-)清除率的IC 50值分别为1.71、1.43和5.37 mg/mL。研究数据为梁平柚柚皮的开发利用提供了一定参考。

To improve the comprehensive utilization rate of Liangping pomelo peel,a single factor experiment and response surface methodology were used to optimize the enzymatic assisted extraction process parameters of polysaccharide from Liangping pomelo peel.The structure of it was characterized by liquid chromatography-mass spectrometry,ultraviolet spectrum,infrared spectroscopy,and scanning electron microscope,and the antioxidant activity in vitro was investigated.The optimum extraction conditions were as follows:the liquid-solid ratio was 25∶1(mL∶g),the pH was 6.0,the enzymolysis time was 90 min,and the enzymolysis temperature was 50℃.Under these conditions,the extraction rate of polysaccharide was 5.46%.The monosaccharide composition showed that it was mainly composed of ribose(1.18%),glucuronic acid(1.32%),mannose(4.26%),rhamnose(4.72%),glucose(11.46%),galactose(21.48%),galacturonic acid(23.67%)and arabinose(31.90%);the results of UV and IR spectra showed that it was acidic polysaccharide with pyranose ring and linked byβ-glucoside bond,and contained no protein and nucleic acid.The results of the scanning electron microscope showed that it had lamellar and fibrous structures.In addition,the results of in vitro antioxidant experiment showed that the antioxidant activities was dose-dependent in a certain concentration range.And the IC_(50) of DPPH radical scavenging rate,hydroxyl radical scavenging rate and superoxide anion radical scavenging rate were 1.71,1.43 and 5.37 mg/mL,respectively.This study can provide a reference for the development and utilization of Liangping pomelo peel.