An oligosaccharide is a carbohydrate composed of a small number of monosaccharide (simple sugar) units, typically between three and ten. Oligosaccharides occur naturally in plants and animals and play various biological roles.
Oligosaccharides that play a dietary role include raffinose, stachyose, verbascose, inulin, fructo and galacto-oligosaccahrides. They are present in legumes, beans, cabbage, broccoli, brussel sprouts, onions, artichoke, fennel, asparagus, beans and peas, and are also frequently included in pre-biotic supplements.