两步法高效制备玉米芯木寡糖的工艺研究

Studies on Extraction and Preparation of Xylooligosaccharides from Corncobs

以玉米芯为原料,通过碱提醇沉法和酶水解法两步高效提取制备木寡糖。玉米芯成分分析结果表明,玉米芯中水分含量为(12.06±1.23)%,粗纤维含量为(43.34±0.49)%,粗灰分含量为(1.87±0.03)%,脂肪的含量为(0.67±0.02)%,可溶性蛋白质含量为(0.07±0.01)%,可溶性糖含量为(0.34±0.01)%,还原糖含量为(0.13±0.01)%,木质素含量为(28.47±0.87)%。通过单因素和正交试验确定了碱提醇沉法提取玉米芯木聚糖粗品的工艺为:提取温度85℃,碱质量分数15%,料液比1∶15(g/m L),提取时间150 min,该工艺条件下木聚糖得率为12.44%。通过正交试验确定了酶解制备木寡糖的最佳工艺条件为底物浓度40 g/L,酶含量0.02%,反应时间4 h。在此条件下酶解制备木寡糖相对含量为89.61%。

The extraction and preparation of xylooligosacchrides through alkali extraction and alcohol precipi-tation method and enzymatic hydrolysis from Corncob were studied. Firstly, the composition of corncobs was an-alyzed. The result indicated that moisture, crude fiber content,crude ash content, fat content, protein content, soluble sugar content,reducing sugar content, xylogen content of corncobs were amounted to （12.06±1.23）%, （43.34±0.49）%,（1.87±0.03）%,（0.67±0.02）%,（0.07±0.01）%,（0.34±0.01）%,（0.13±0.01）%, （28.47± 0.87）%, respectively. The extraction processing of xylan from the corncob was established through single factor experiment and orthogonal test as the followings：corncob powder was mixed with 15%sodium hydroxide at the ratio of 1：15（g/mL） and the mixture was heated to 85℃for 150 min. Under this condition, the yield of corncob xylan was 12.44%. The processing parameters of xylan hydrolysis by xylanase were optimized as the substrate concentration of 40 g/L, xylanase dosage of 0.02%, hydrolysis for 4 h. Under this condition, the yield of xy-looligosaccharides was 89.61%.