Transglycosylation specificity of glycosyl donors in transglycosylation of stevioside catalysed by cyclodextrin glucanotransferase.
Specificity of glycosyl donors is a critical issue in transglycosylation of stevioside, the main methodology to improve edulcorant quality of stevioside. The most popular glucanotransferase applied in this reaction is cyclodextrin glucanotransferase (CGTase) that catalyses cyclisation, coupling, hydrolysis and disproportionation simultaneously; which results a crosstalk in the glycosyl donors that comes from initial reactants, reaction intermediates as well as side products in parallel reactions. In this work, the specificity of glycosyl donors was studied to understand the transglucosylation pathways with the designed experiments and material balance analysis on the products using a commercial CGTase. It has been found that cyclodextrins and starches provided the best transglucosylation yield, while the assayed mono- and disaccharides were not effective glycosyl donors to stevioside with the CGTase. It is proposed that α- and β-cyclodextrins performed transglycosylation via coupling to produce intermediates of reducing sugar and followed by disproportionation with stevioside; while starches may perform the transglycosylation combined the cyclodextrins pathway and hydrolysis pathway of starches.
State Key Laboratory of Food Science and Technology, School of Chemical and Materials Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China.
Tong
T
Lu
State Key Laboratory of Food Science and Technology, School of Chemical and Materials Engineering, Jiangnan University, Wuxi, Jiangsu 214122, China. Electronic address: ymxia@jiangnan.edu.cn.
Yong-mei
YM
Xia
D002384:Catalysis; D045786:Diterpenes, Kaurane / Q000378:metabolism*; D005960:Glucosides / Q000378:metabolism*; D005964:Glucosyltransferases / Q000378:metabolism*; D006031:Glycosylation; D006868:Hydrolysis; D013213:Starch / Q000737:chemistry; D013549:Sweetening Agents / Q000378:metabolism*
D045786:Diterpenes, Kaurane; D005960:Glucosides; D013549:Sweetening Agents; C012043:stevioside; D013213:Starch; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase
Cyclodextrin; Cyclodextrin glucanotransferase; Starch; Stevioside; Sweetener; Transglycosylation