Synthesis of Neohesperidin Glycosides and Naringin Glycosides by Cyclodextrin Glucano-transferase from an AlkalophilicBacillusSpecies

Cyclodextrin glucanotransferase from an alkalophilic Bacillus species produced neohesperidin monoglucoside and a series of its maltooligoglucosides by transglycosylation with neohesperidin as an acceptor and soluble starch as a donor. As the reaction using beta-CD as a donor at an alkaline pH was very effective for solubilizing neohesperidin, the amount of glycosides formed was increased. As a result, its amount with beta-CD at pH 10 was about 7 times greater than that with soluble starch at pH 5. Neohesperidin monoglucoside was purified from the reaction mixture by glucoamylase and naringinase treatments, an Amberlite XAD-16 column, a Sephadex LH20 column, and HPLC on an ODS column. The structure of the purified monoglucoside was identified as 3G-alpha-D-glucopyranosyl neohesperidin by FAB-MS, methylation analysis, and 1H- and 13C-NMR. The solubility of neohesperidin monoglucoside in water was approximately 1500 times higher than that of neohesperidin, and the bitterness of the monoglucoside was about 10 times less than that of neophesperidin. In addition, naringin was also glycosylated by the same method as neohesperidin, and its monoglucoside was identified as 3G-alpha-D-glucopyranosyl naringin. The solubility of naringin monoglucoside in water was also at least 1000 times higher than that of naringin without altering its bitterness.