Jerusalem artichoke flour as food ingredient and as source of fructooligosaccharides and inulin

Jerusalem artichoke tuber is one of the main sources of fructans (inulin and fructooligosaccharides) along with chicory roots. Its ease of cultivation and good production yield make this tuber a valuable underutilized ingredient, but its short shelf life demands its conversion to a more stable form. Jerusalem artichoke flour from whole (unpeeled) tubers resulted rich in minerals, especially potassium (27.6 mg/g db), and showed a partic-ularly high water retention capacity, being able to retain more than three times its weight in water. This was related to its total dietary fiber content (13.0% db). Fructans were extracted from Jerusalem artichoke flour with similar efficiency as from the tuber (85.0% and 87.8% db, respectively). The diffusion syrup was concentrated by rotavapor or by evaporation on a hot plate, and fructans were precipitated by freeze-thaw cycles or alcoholic precipitation. All the fructan powders obtained showed lower whiteness indexes (61.5-67.3) than commercial inulin from chicory roots (97.5). No significant differences were observed in the fructans obtained from both concentration methods. Alcoholic precipitation showed the highest yield (14.8-16.3%), MW (7190-7870 Da), and whiteness index (66.9-67.3), while freeze-thaw cycles provided MW of 5850-5950 Da and showed greater similarity in their FTIR spectra with commercial inulins (>94%).