枳椇子多糖的酸提取工艺优化及其理化性质与抗氧化活性研究

Optimization of acid extraction process for polysaccharide from Hovenia dulcis seed and analysis of its antioxidant activity

为优化枳椇子多糖的提取工艺,并对其理化性质和抗氧化活性进行研究。该研究采用酸溶剂提取枳椇子粗多糖,经单因素考察和正交试验优化提取工艺参数,通过Sevag法除蛋白、DEAE-52阴离子交换柱对多糖进行分离纯化,得到枳椇子精制多糖。采用高效液相色谱、紫外光谱、傅里叶变换红外光谱、刚果红实验、碘-碘化钾和扫描电镜等方法对枳椇子多糖进行理化性质分析;对枳椇子多糖的体外抗氧化活性进行评价。结果表明,枳椇子多糖的最佳提取工艺为温度90℃,料液比为1∶100(g∶mL),时间2.5 h,盐酸浓度0.2 mol/L,在此条件下多糖得率为(4.07±0.07)%。经分离纯化后获得分子质量为3.03×10^(5)Da的均一性枳椇子精制多糖(Hovenia dulcis polysaccharide,HDP),HDP由甘露糖、氨基葡萄糖、鼠李糖、葡萄糖醛酸、半乳糖醛酸、葡萄糖、半乳糖、鼠李糖、阿拉伯糖组成,摩尔百分比为10.46%、1.44%、8.19%、9.79%、4.54%、4.61%,、38.02%、9.95%、13.01%。结构鉴定HDP为吡喃环型酸性多糖,具有无规则螺旋的空间构象且含有较多分支,并表现出片层状的微观形态。HDP清除ABTS阳离子自由基、DPPH自由基和羟自由基的IC_(50)值分别是0.867、1.178、2.112 mg/mL。该研究通过优化酸提枳椇子多糖工艺,获得一种精制的酸性多糖HDP,并揭示HDP具有潜在的抗氧化活性,该研究结果将为枳椇子多糖的功能食品开发提供理论依据。

This study aimed to optimize the extraction process of Hovenia dulcis polysaccharide and investigate its physicochemical properties and antioxidant activity.The crude polysaccharide of H.dulcis was extracted by acid solvent,and the extraction process parameters were optimized by single-factor investigation and orthogonal experiment.The polysaccharide of H.dulcis was separated and purified by the Sevag method and DEAE-52 anion exchange column,the physical and chemical characteristics were analyzed using high-performance liquid chromatography,high-performance gel permeation chromatography,ultraviolet spectrum,Fourier transform infrared spectrometer,Congo red test,potassium iodide,and scanning electron microscope.The antioxidant activity of H.dulcis polysaccharides was further analyzed.Experimental results indicated that the most quantity of polysaccharide extracted from H.dulcis reached up to 4.07%,in the conditions of the solid-liquid ratio being 1∶100,90℃of the extraction temperature,150 min of the extraction time.After separation and purification,this study obtained a homogeneous refined polysaccharide from H.dulcis,named HDP with a molecular weight of 3.030×10^(5)Da,which was a pyran ring acidic polysaccharide with many branches.HDP was composed of mannose,glucosamine,rhamnose,glucuronic acid,galacturonic acid,glucose,galactose,rhamnose,and arabinose,with molar percentages of 10.458%,1.442%,8.187%,9.788%,4.536%,4.606%,38.024%,9.948%,and 13.009%.In addition,HDP exhibited a lamellar micromorphology.It was also found that the IC_(50)values of HDP for scavenging ABTS cationic radicals,DPPH free radicals,and hydroxyl radicals were 0.867 mg/mL,1.178 mg/mL,and 2.112 mg/mL,respectively.Therefore,this study obtained a refined acidic polysaccharide HDP by optimizing the acid extraction process of H.dulcis polysaccharides and revealed that HDP had potential antioxidant activity.The results of this study could provide a theoretical basis for the development of functional food of H.dulcis polysaccharides.