石榴皮多糖硒酸酯制备工艺参数优化及其结构分析

Optimized Preparation and Structural Analysis of Polysaccharide Selenate from Pomegranate Rind

以石榴皮多糖与亚硒酸钠为原料制备石榴皮多糖硒酸酯,以产物硒含量和收率为指标,原料配比、硝酸体积分数、反应温度和反应时间为单因素,通过单因素试验和Box-Behnken试验设计方法对工艺条件进行优化,并对产物结构进行分析。结果显示:石榴皮多糖硒酸酯最佳制备工艺条件为原料配比1:1.0(g/g)、硝酸体积分数0.61%、反应温度77.0℃、反应时间11.3 h,在该工艺条件下,制得石榴皮多糖硒酸酯中硒含量为4.48 mg/g,产物收率为41.87%;紫外光谱、红外光谱和热重分析充分证实石榴皮多糖硒酸酯中含有Se=O键、Se—O键和Se—C键。优化后的石榴皮多糖硒酸酯制备工艺条件实现了石榴皮多糖的硒化,为石榴皮资源的充分开发利用提供良好条件。

In this paper, polysaccharide selenate was prepared via the reaction between pomegranate rind polysaccharide and sodium selenite. Four reaction conditions including ratio between the substrates, final HNO3 concentration, reaction temperature and time were optimized based on the selenium（Se） content and yield of product using single factor experiments and Box-Behnken experimental design. At the same time, the structure of the obtained product was analyzed. Results showed that the optimum reaction conditions for preparing polysaccharide selenate were established as follows： ratio between pomegranate rind polysaccharide and sodium selenite, 1：1.0（g/g）; final HNO3 concentration, 0.61%; temperature, 77.0 ℃; and time, 11.3 h. Under these conditions, the Se content and yield of polysaccharide ester selenate were 4.48 mg/g and 41.87%, respectively. Ultraviolet spectroscopic（UV）, infrared spectroscopic（IR） and thermogravimetric analyses（TGA）fully confirmed that the polysaccharide ester selenate contained Se=O, Se-O and Se-C. The selenization of pomegranate rind polysaccharide under the optimized reaction conditions can create a good condition for the full development and utilization of pomegranate rind resources.