SYNTHESIS OF HESPERIDIN GLYCOSIDES BY CYCLODEXTRIN GLUCANOTRANSFERASEAND STABILIZATION OF THE NATURAL PIGMENTS

An improved method for the synthesis of hesperidin glycosides was deve loped using both beta-cyclodextrin (beta-CD) and alpha-rhamnosidase tr eatments. The reaction, which contained 0.5% (8.2 mM) hesperidin as an acceptor, 5% soluble starch as a donor and 2 units/ml of cyclodextrin glucanotransferase (CGTase) from an alkalophilic Bacillus species was incubated at 40 degrees C and pH 10 for 16 h, was used as the standar d reaction. During the transglycosylation reaction, both beta-CD and a n alkaline pH were very effective for solubilizing hesperidin, and the amount of hesperidin glycosides formed by CGTase with 5% B-CD as a do nor at pH 10 was about 50 times greater than the amount formed with so luble starch at pH 5. During the purification steps, alpha-rhamnosidas e hydrolyzed the unreacted hesperidin into lower molecular weight and more hydrophobic compounds (hesperetin-7-glucoside), but it did not hy drolyze the hesperidin glycosides. Therefore, hesperidin glycosides we re easily separated from the unreacted hesperidin using Sephadex LH-20 . Various kinds of natural pigments were stabilized against ultraviole t radiation using the prepared hesperidin glycosides.