A dietary fiber composition comprising at least one cereal grain component containing β-glucan, characterized in that the β-glucan is selected to have a maximum molecular weight in the range of 500 kDa to 3000 kDa, a solubility at 37 oC of at least 50% of ß-glucan extracted with respect to the total content of ß-glucan in an extract of the fiber composition, and with a viscosity of the extract at 37 oC of at least 500 mPa.s measured at 30 s-1； the extract being prepared by mixing a 5 g sample of the fiber composition in an Erlenmeyer flask with 75 ml of 20 mM sodium phosphate buffer, pH 6.9, containing 10 mM NaCl； stirring the mixture slowly for 15 min at 37 oC； addition of 250 μl of human salivary α-amylase solution (5 mg / ml in 3.6 mM CaCl2)； stirring the mixture for an additional period of 15 min； pH adjustment to 2.0 with 6M HCl and 1M； addition of 625 μl of swine pepsin solution (0.5 mg / ml in 0.9% NaCl)； incubation of the mixture for 30 min at 37 oC； pH adjustment to 6.9 with 3M NaOH； adding 1.25 ml of pancreatin solution (0.5 mg / ml in 20 mM sodium phosphate buffer containing 10 mM NaCl)； incubation continued for 90 min； and centrifugation of an aliquot for 10 min at 7,000 x g.Una composicion de fibra dietetica que comprende al menos un componente de grano de cereal que contiene ß- glucano, caracterizada por que el ß-glucano se selecciona para que tenga un peso molecular maximo en el intervalo de 500 kDa a 3000 kDa, una solubilidad a 37 oC de al menos un 50 % de ß-glucano extraido con respecto al contenido total de ß-glucano en un extracto de la composicion de fibra, y con una viscosidad del extracto a 37 oC de al menos 500 mPa.s medido a 30 s-1； preparandose el extracto por mezcla de una muestra de 5 g de la composicion de fibra en un matraz Erlenmeyer con 75 ml de tampon de fosfato sodico 20 mM, pH 6,9, que contiene NaCl 10 mM； agitacion de la mezcla lentamente durante 15 min a 37 oC； adicion de 250 μl de solucion de α-amilasa salivar humana (5 mg/ml en
