Provided is a method for manufacturing crystalline isomaltulose from
sucrose, comprising the steps of: 1) contacting an
.alpha.-glucosyltransferase enzyme to aqueous sucrose solution or slurry
under the condition wherein the .alpha.-glucosyltransferase enzyme is
active; in which said condition is maintained after the concentration of
isomaltulose in the reaction mixture reaches the point at which crystals
are formed, and 2) separating the reaction mixture into crystalline
isomaltulose and remaining syrup. According to the present invention,
enzymatic conversion of sucrose and crystallization of isomaltulose are
carried out simultaneously in a same reaction vessel. In addition, the
enzyme can be used repeatedly.
