Inulin was found to be a semi-crystalline material, which presents both the existence of a glass transition temperature and a melting transition. At room temperature, its glass transition occurred at 18% (d.b.) moisture content, corresponding to Aw values close to 0.75. When pre-solubilized and stored below its Tg, inulin remains in a low-crystalline state (∼13% relative crystallinity), while at conditions above Tg, recrystallization occurs and it reaches ∼40% relative crystallinity (same value as native inulin). Inulin's functionality in foods, such as fat-mimetic properties, might then be a consequence of its semi-crystalline properties and glass transition temperature, which are influenced by storage conditions such as moisture.