The roots contain a substantial amount of the prebiotic fiber inulin. Inulin is a naturally occurring polysaccharide. Resistant starch, inulin, fructooligosaccharide and galactooligosaccharide are dietary fibers which are fully fermented. Dried chicory root extract contains, by weight, about 98% inulin and 2% other compounds. Inulin may also be synthesized from sucrose. Hydrolyses inulin and levan, and also sucrose. Its sweet flavor comes from the oligofructose inulin (also called fructo-oligosaccharide), which is a prebiotic. Inulin is a heterogeneous collection of fructose polymers. Chicory root is the main source of extraction for commercial production of inulin. Fresh chicory root may contain between 13 and 23% inulin, by total weight. Individuals with digestive diseases have benefited from removing fructose and inulin from their diet. Some traditional diets contain over 20 g per day of inulin or fructo-oligosaccharides. Tubers stored for any length of time convert their inulin into its component fructose. In Asteraceae, the energy store is generally in the form of inulin rather than starch. This heart is stripped of its leaves and heated to convert the inulin to sugars.