Isomaltose

Isomaltose is a disaccharide composed of two α-D-glucose units linked by an α‑1,6 glycosidic bond. Its chemical formula is C12H22O11, and the molecule is non‑reducing because the anomeric carbon of the non‑reducing end is locked in the glycosidic linkage. The α‑1,6 linkage distinguishes it from maltose, which has an α‑1,4 bond. Isomaltose can be produced enzymatically by the action of α‑glucosidases that cleave longer dextrin chains, or it can be isolated from the hydrolysis of starch under specific conditions that favor α‑1,6 bond formation.

The sugar is naturally found in small amounts in foods containing partially hydrolyzed starch such as certain cereals and in the hydrothermal vents where thermophilic microorganisms produce oligosaccharides with alternating α‑1,4 and α‑1,6 linkages. In the laboratory, it is also synthesized via acid or enzymatic methods that convert starch or glycogen fragments into a mixture of disaccharides, among which isomaltose is a major component.

Isomaltose is water‑soluble and has a sweetness level that is lower than sucrose but higher than most other saccharides. It is often used as an intermediate in the synthesis of larger oligosaccharides, especially for the creation of branched glycans. Because of its relative resistance to enzymatic breakdown, it can influence the texture and stability of food products, serving as a texturizer and humectant in confectionery and bakery items.

In addition to food applications, isomaltose is studied as a potential low‑calorie sugar for nutritionally tailored foods. Its limited caloric value and modest glycemic impact make it attractive for use in dietetic formulations. Research into its role as a glucose source in fermentation processes has also been reported, though commercial utilization remains limited compared with more common sugars.