noun, plural: isomaltoses
Isomaltose is a disaccharide with a chemical formula of C12H22O11 and it is comprised of two glucose units. In this regard, isomaltose is similar to maltose. The difference is on the glycosidic linkage that joins two glucose units. In maltose, the glucose molecules are linked together by an alpha-1→4 glycosidic bond. In isomaltose, the linkage is an alpha-1→6 glycosidic bond.
Similar to maltose, the isomaltose is a reducing sugar. Since it has only one of the two anomeric carbons in the glycosidic bond, it can turn into an open-chain form with its functional group acting as a reducing agent.
Isomaltose is one of the main constituents in isomalto-oligosaccharide (IMO), the others are isomaltotriose, isomaltotetraose, isomaltopentaose, panose, kojibiose, etc. These carbohydrates are linked together by an alpha-D-(1,6)-linkages to form isomalto-oligosaccharide. IMO is produced naturally in fermented foods, e.g. soy sauce and sake. In humans, the alpha-(1,6)-linkages are not as easily hydrolyzed as the alpha-(1,4)-linkages. Thus, IMO is relatively not easy to digest.
Word origin: isos- ("equal") + malt + -ose (a suffix used in chemical naming of sugars)