DESCRIPTION

Galacto-oligosaccharides (GOS) occur as a white, pale yellow amorphous powder, or a colorless, pale yellow, viscous syrup. Galacto-oligosaccharides are produced through enzymatic conversion of lactose using β-galactosidase. Galacto-oligosaccharides are substances comprising between 2 and 8 saccharide units, with one of these units being a terminal glucose and the remaining saccharide units being galactose, and disaccharides comprising two units of galactose. Typically, the oligosaccharides in GOS are linked via β-glycosidic bonds with 1-3, 1-4, or 1-6 anomeric configurations. Although tri- to hexa-saccharides with 2–5 galactose units tend to be the main components of galacto-oligosaccharides, disaccharides consisting of galactose and glucose with β-glycoside bonds different from lactose are also present. Some galacto-oligosaccharides contain trace amounts of oligosaccharides with 9–10 saccharide units. The degree of polymerization of galacto-oligosaccharides can vary markedly, depending mainly on the specific enzyme and manufacturing conditions used.