Study on preparation and separation of Konjac oligosaccharides

► Konjac oligosaccharides were prepared by γ-irradiation and β-mannanase. ► It was analyzed by gel permeation chromatography and ion exchange column in HPLC. ► The oligosaccharides could be effectively separated by ultrafiltration. To study the preparation and separation of Konjac oligosaccharides, Konjac Glucomannan was degraded by the combination of γ-irradiation and β-mannanase, and then the degradation product was separated by ultrafiltration. To our interest, for most of Konjac oligosaccharides obtained by this method, the molecular mass was lower than 2200Da. In addition, the 1000Da molecular weight cut off membrane could effectively separate the Konjac oligosaccharides. In conclusion, the combination of γ-irradiation and β-mannanase was an efficient method to obtain Konjac oligosaccharides, and the oligosaccharides of molecular mass lower than 1000Da could be effectively separated by ultrafiltration.