inulin

 A substance of very wide occurrence. It is found dissolved in the sap of the roots and rhizomes of many composite and other plants, as Inula, Helianthus, Campanula, etc., and is extracted by solution as a tasteless, white, semicrystalline substance, resembling starch, with which it is isomeric, having fructose units in place of most of the glucose units. It is intermediate in nature between starch and sugar, and replaces starch as the reserve food in Compositae. Called also dahlin, helenin, alantin, alant starch, etc.  [1913 Webster]