甜菊糖是一类被广泛使用的天然高倍甜味剂。本文研究了一种新的来源于Paneibacillusmacerans JFB05-01的α-环糊精葡萄糖基转移酶催化甜菊苷(St)的转糖苷反应,以此克服其后苦涩味这一致命缺点。最终优化条件为:60℃下,以水为溶剂,淀粉水解液作为糖基供体,浓度为15 mg/mL,甜菊苷浓度为10 mg/mL,加酶量为15 U/g St,3 h后可到平衡,甜菊苷的转化率可达59.2%,St-Glu 1的产率为32.4%。转苷产品经淀粉糖化酶水解0.75 h,St-Glu 1含量提高至43.1%。转苷产物的溶解度提高60倍以上,后苦涩味明显改善。

Steviol glycosides have been used widely as natural intensive sweeteners.The transglycosylation of stevioside with cornstarch hydrolysate catalyzed was investigated using a new α-cyclodextrin glucanotransferase from Paneibacillus macerans JFB05-01.Optimum conditions were as fellows: 60 ℃,DI water as solvent,cornstarch hydrolysate 15mg/mL and stevioside 10mg/mL,enzyme loading 15 U/g St,3h,final conversion of stevioside and yield of St-Glu 1 were 59.2% and 32.4%,respectively.The hydrolysis of transglycosylated products with glucoamylase increased St-Glu 1 to 43.1%.Solubility of glycosylated derivatives was 60 times as high as that of stevioside,whose taste was improved as well.