【摘要】 以纤维素酶水解胡芦巴半乳甘露聚糖所得产物1为原料;用普鲁兰酶水解产物1侧链的α-1,6糖苷键,以还原糖得率为指标,通过L9(34)正交试验优化了制备低相对分子质量胡芦巴半乳甘露聚糖(产物2)的工艺,并对产物进行了表征。试验结果表明,普鲁兰酶的最佳工艺条件为:酶用量为2000ASPU/g,酶解时间2h,pH值5.2,酶解温度60℃,此时还原糖得率为43.8%。用黏度法测得水解产物2的黏均相对分子质量(MV)为5.10×104。红外光谱结果表明,1595cm-1的—OH吸收峰和1402cm-1处C—H的变角振动吸收峰变强,由此说明胡芦巴半乳甘露聚糖的糖苷键断裂,羟基的数量增加。X射线衍射图谱结果表明,胡芦巴半乳甘露聚糖的结晶区只受轻微破坏,由此说明酶解反应主要发生在胡芦巴半乳甘露聚糖的非结晶区。更多还原

【Abstract】 The degradation technology of fenugreek galatomannan by enzymatic hydrolysis was studied to prepare low-molecular-mass fenugreek galactomannan. Fenugreek galactomannan and hydrolysis product were further characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Fenugreek galactomannan was pretreated using cellulase and then hydrolyzed by pullulanase. Optimization of the reaction parameters was carried out using L9(34) orthogonal tests, using the yield of reducing sugar as index .The optimal reaction conditions were obtained as follows: enzyme dosage 2000ASPU/g, treatment time 2h with pH value 5.2 at 60℃. The yield of reducing sugar was 43.8% with the average viscosimetric molecular weight (MV) of 5.10×104. The results of FT-IR indicated the breakage of glycosidic linkage and the increase of hydroxyl groups. In the crystallized area of the fenugreek gum, only slight degradation was observed by XRD results, which indicated that degradation reaction mainly occurs in the non-crystalline region of fenugreek galactomannan.更多还原