白酒丢糟酸水解制备木糖及其结构变化

Production of xylose from distiller's grains(DG) by acid hydrolysis and the structural change of DG

采用混合酸水解法提取白酒丢糟中的木糖,并研究木糖提取过程中丢糟的结构变化。以木糖收率为指标,考查酸解温度、固液比、混合酸浓度和酸解时间4个因素对木糖提取效果的影响,利用正交试验优化工艺参数。结果表明,从丢糟中提取木糖的最优条件为温度110℃、固液比1∶12(g∶mL)、混合酸浓度1.5%和时间145min,该条件下的木糖收率为61.24%。经酸水解法提取木糖后,丢糟的木质纤维结构变化明显,孔隙率和比表面积增加,形貌结构改变,半纤维素和纤维素无定形区被降解,导致结晶度增加。

The method of mixed acid hydrolysis was used to produce xylose from distiller＇s grains （DG）, and the structural changes of DG during the production of xylose were investigated with X-ray diffraction （XRD） and scanning electronic microscopy （SEM）. In order to improve the yield of xylose, the key parameters including temperature, mixed acid concentration, solid-liquid ratio and acid hydrolysis time were investigated by means of orthogonal test. The optimal levels for the highest yield of xylose were obtained under the conditions of temperature of ll0~C , solid-liquid ratio of 1： 12（g： mL）, mixed acid concentration of 1.5% , time of 145 min. The yield of xylose reached 61.24% under opti- mized conditions. Studies on the structure of DG during the production of xylose showed that the lignoeellulosic structur- al changes undergone by acid hydrolysis were obvious. The disruption of lignoeellulosic structure resulted in the increas- ing surface exposure and porosity of acid hydrolysis residues. The crystallinity of acid hydrolysis residues was increased by comparison of DG, as a result of the degradation of hemieellulose and the amorphous region of cellulose.