Oligosaccharides

Oligosaccharides are carbohydrates comprising between three and ten monosaccharide units linked by glycosidic bonds, occupying the size range between simple sugars and polysaccharides. They are synthesised either by limited hydrolysis of polysaccharides or by the addition of monosaccharides, a process catalysed by glycosyltransferase enzymes. In foods they occur naturally in legumes, where raffinose and stachyose cause flatulence, and in human milk, where they nourish beneficial gut bacteria. Commercial fructo- and galacto-oligosaccharides are added as prebiotic fibres to infant formula, yoghurts, and functional foods. Their low digestibility, mild sweetness, and fermentability by colonic microflora make them valuable tools for gut-health positioning.