小麦制粉产物中阿糖基木聚糖的制备及其分子特性研究

Preparation and Molecular Characteristics of Arabinoxylans from Different Wheat Milling Fractions

以小麦为原料,研究了小麦麸皮、小麦次粉和小麦粉中阿糖基木聚糖的得率、单糖组成、阿拉伯糖与木糖质量比、分子量和分子量分布等性质。结果表明:小麦麸皮、小麦次粉和小麦粉的阿糖基木聚糖得率分别为8.99%、7.28%和1.12%,其单糖组成主要为阿拉伯糖和木糖。小麦麸皮中的阿糖基木聚糖具有较低的阿拉伯糖与木糖比,表明其直链较少。HPSEC分析结果表明小麦粉阿糖基木聚糖分子量最高,而麸皮阿糖基木聚糖分子量最低。动态光散射分析得出三种阿糖基木聚糖水溶液的粒度大于其碱性溶液粒度,表明阿糖基木聚糖在不同的溶液中具有不同的聚合度。对三种阿糖基木聚糖进行回收率分析显示,1.0 M NaOH溶液可作为阿糖基木聚糖的良好溶剂,而水作为溶剂效果较差。综上所述,小麦麸皮、小麦次粉可作为阿糖基木聚糖的有效资源。

Arabinoxylans prepared from wheat bran, shorts and flour were characterized by monosaccharide composition, weight ratio of arabinose and xylose, molecular weight and molecular weight distribution. The yields of ambinoxylans from bran （WBAX）, shorts （WSAX） and flour （WFAX） were 8.99%, 7.28% and 1.12%, respectively. Arabinose and xylose were the main monosaccharide. WBAX had the lowest Ara/Xyl ratio compared with WSAX and WFAX, indicating it had less linear chain. HPSEC analysis showed that WFAX possessed the highest molecular weight, while WBAX had the lowest molecular weight. Dynamic light scattering （DLS） studies found that the particle size of the three arabinoxylans in water was larger than in alkaline solution, suggesting the degree of aggregation of arabinoxylans varied in different solvents. Based on the recovery of WBAX, WSAX and WFAX from different solvents by DLS analysis, 1.0 M NaOH solution exhibited good solvent property for wheat arabinoxylans. In contrast, water appeared to be a poor solvent. All results showed that wheat bran and shorts could be used as effective resources for arabinoxylans.