The invention concerns a method for preparing a polydispersed saccharide composition poor in glucose (G), fructose (F) and saccharose (GF) containing at least 93.5% by weight per dry matter of fructo-oligosaccharides constituted by a chain of fructose units with a terminal glucose of formula GFn, n and m being between 2 and 20 and comprising a content of glucose, fructose and saccharose in total less than 5% by weight per dry matter. The method consists in subjecting a substance containing fructanes to partial hydrolysis, the said substance containing fructanes of an average degree of polymerisation not less than 7 and containing glucose, fructose and saccharose in total at most 3.5% by weight per dry matter.
