Oligosackarider

Oligosackarider (oligosaccharides) are carbohydrates composed of a small number of monosaccharide units, typically 3 to 10, linked by glycosidic bonds. They are intermediates between simple sugars (monosaccharides and disaccharides) and larger polysaccharides. They occur in plants and animals and are often part of glycoproteins and glycolipids when attached to proteins or lipids.

Structural variety: they can be linear or branched; linkages include alpha- and beta-glycosidic bonds, making them resistant or susceptible to enzymatic digestion. Common examples include raffinose and stachyose—tris- and tetrasaccharides consisting of galactose, glucose, and fructose units. In plants, raffinose family oligosaccharides serve as transport carbohydrates and osmoprotectants.

Biological roles and metabolism: in humans, most oligosaccharides are not digestible due to lack of certain glycosidases, so they reach the colon where gut microbes ferment them, producing short-chain fatty acids and gases; some oligosaccharides act as prebiotics and support beneficial bacteria. Oligosaccharides are also used as attachment points in glycoproteins and glycolipids, affecting cell recognition and signaling.

Analytical aspects and food relevance: oligosaccharides are analyzed in food science and nutrition; their presence influences flavor, texture, and digestibility; processing can reduce levels (e.g., enzymatic treatment or fermentation).

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