Oligosaccharide

Oligosaccharides ( Gr. oligos - few ) are carbohydrates (sugars ) composed of several identical or different monosaccharides ( simple sugars ) are lined up and connected to each other by glycosidic bonds. Corresponding to the number of monosaccharide units present is referred to as di-, tri -, tetra-, pentasaccharides etc., which may be linear ( unbranched) and branched. Connections of many monosaccharides are called polysaccharides. The demarcation between oligo -and polysaccharides is fluid, but usually you go in oligosaccharides of from three to ten monosaccharides connected. According to another source consist oligosaccharides of from two to ten monosaccharide units.

Properties

The physical and sensory properties are similar to those of the monosaccharides. This also applies to the reactions in which, however, the difference between the reducing and non-reducing oligosaccharides is observed. The non-reducing not exhibit the reducing ability, mutarotation and reactions with alcohols and amines. Since it is glycosides, oligosaccharides are readily hydrolysed by acids, but to bases stable.

Galacto-oligosaccharides (GOS ) are composed of one to seven galactose and a glucose unit; they do not occur in cow, but in breast milk and affect bifidogenic ( prebiotic ). Some oligosaccharides have antibiotic effects.

Biochemistry

Oligosaccharides are often bound to proteins and lipids, for example, in the cell membrane and play a role in cell recognition. Among other things, they determine the blood groups according to the AB0 system.