[ Fructooligosaccharide, FOS, oligofructose, oligofructan ]
An oligosaccharide fructan that is a source of dietary fibre (prebiotic). It is fermented in the upper larger intestine by anaerobic bacteria.
As an alternative sweetener, FOS has sweetness levels between 30 and 50 percent of sugar and is therefore usually combined with higher-intensity sweeteners in food products such as yogurt.
FOS has been proposed as a prebiotic dietary supplement and as treatment for yeast infections.