小米谷糠多糖的提取小米谷糠多糖的提取、羧甲基化修饰及其羧甲基化修饰及其功能特性

Extraction,Carboxymethylation Modification and Functional Properties of Millet Bran Polysaccharides

以小米谷糠为原料,采用超声辅助酶法从小米谷糠中提取多糖,优化提取工艺,并对其进行羧甲基化修饰,探究小米谷糠多糖羧甲基化前后的加工特性和抗氧化活性。结果表明:小米谷糠多糖最佳提取条件为提取温度96℃、提取时间186 min、料液比1∶22(g/mL)、超声时间32 min,多糖得率可达8.21%。红外光谱分析结果表明小米谷糠多糖成功引入COO—。功能特性研究结果显示,小米谷糠多糖、羧甲基化小米谷糠多糖持水性分别为1.78 g/g和3.13 g/g;持油性分别为3.43 g/g和5.64 g/g;乳化性分别为10.58%和22.33%;乳化稳定性分别为56.49%和57.38%;起泡性分别为53.75%和50.87%;泡沫稳定性分别为39.32%和41.93%。羧甲基化修饰后,多糖对自由基的清除能力增强,对DPPH·、·OH和O2-·清除率最高分别为78.21%、64.27%、70.27%,较修饰前分别提高了12.32%、17.09%、9.35%。因此,小米谷糠多糖和羧甲基化小米谷糠多糖均具有良好的加工特性和较强的抗氧化活性,而羧甲基化修饰可明显提高其抗氧化活性。

Ultrasound⁃assisted enzymatic hydrolysis method was employed to extract polysaccharide from mil⁃let bran.The extraction process was optimized and carboxymethylation modification was carried out to investi⁃gate the processing characteristics and antioxidant properties of millet bran polysaccharides before and after carboxymethylation modification.The results were as follows:The optimum extraction conditions were an ex⁃traction temperature of 96℃,extraction time of 186 min,material⁃liquid ratio of 1∶22(g/mL),and ultra⁃sonic time of 32 min.The polysaccharide yield was 8.21%.The results of infrared spectroscopic analysis showed that COO—was successfully introduced into millet bran polysaccharide.It was also shown that the water⁃holding capacity of millet bran polysaccharide and carboxymethylated millet bran polysaccharide were 1.78 g/g and 3.13 g/g,respectively.The oil⁃holding capacity was 3.43 g/g and 5.64 g/g,respectively.Emulsifying prop erties were 10.58%and 22.33%respectively.Emulsion stability 56.49%,57.38%;foaming property 53.75%,50.87%;foam stability 39.32%,41.93%.After carboxymethylation,the scavenging ability of polysaccharide on free radicals was enhanced,and the highest scavenging rates against DPPH·,·OH,and O2-·were 78.21%,64.27%,and 70.27%,increased by 12.32%,17.09%,and 9.35%,respectively.Therefore,both millet bran polysaccharide and carboxymethylated millet bran polysaccharide had good processing characteris⁃tics and strong antioxidant properties,and carboxymethylation could significantly improve their antioxidant properties.