Patent ID: 7592160

Claim:
A process for producing isomaltitol, comprising the steps of: (a) allowing an α-isomaltosylglucosaccharide-forming enzyme, which forms an α-isomaltosylglucosaccharide with a glucose polymerization degree of at least three and having both the α-1,6 glucosidic linkage as the linkage at the non-reducing end and the α-1,4 glucosidic linkage other than the above linkage, via the α-glucosyl-transfer from a material saccharide having a glucose polymerization degree of at least two and having the α-1,4 glucosidic linkage as the linkage at the non-reducing end, without substantially increasing the reducing power of the material saccharide, to act on a saccharide with a glucose polymerization degree of at least two and having the α-1,4 glucosidic linkage as the linkage of non-reducing end to form said α-isomaltosylglucosaccharide wherein said α-isomaltosylglucosaccharide-forming enzyme has the following physicochemical properties: (1) Molecular weight Having a molecular weight of about 117,000 to about 160,000 daltons when determined on SDS-PAGE (sodium dodecyl sulfate polyacrylamide gel electrophoresis); (2) Isoelectric point Having an isoelectic point of about 4.7 to about 5.7 when determined on isoelectrophoresis using ampholine; (3) Optimum temperature Having an optimum temperature of about 40° C. to about 45° C. when incubated at a pH of 6.0 for 60 min; Having an optimum temperature of about 45° C. to about 50° C. when incubated at a pH of 6.0 for 60 min in the presence of 1 mM Ca 2+ ; (4) Optimum pH Having optimum pH of about 6.0 to about 6.5 when incubated at 35° C. or 60 min; (5) Thermal stability Being stable up to a temperature of about 35° C. to 40° C. when incubated at a pH of 6.0 for 60 min, Being stable up to a temperature of about 40° C. to 45° C. when incubated at a pH of 6.0 for 60 min in the presence of 1 mM Ca 2+ , (6) pH Stability Having a stable pH range at about 4.5 to about 10.0 when incubated at 4° C. for 24 hours; (b) allowing an isomaltodextranase to act on the resulting mixture in the step (a) to form isomaltose; (c) hydrogenating either the resulting mixture in the step (b) directly or the isomaltose, which has been separated from the mixture to form isomaltitol; and (d) collecting the formed isomaltitol.