Kojibiose (2-O-α-D-Glucopyranosyl-D-Glucose): Isolation and Structure: Isolation from Hydrol

Abstract

IT has previously been reported that saké and koji extract produced from rice by the application of Aspergillus oryzae contains two new disaccharides¹, one of which has been confirmed to be 1 : 3-α-linked gluco-biose (kojibiose)^3,4 by its conversion into glucose with acid, R _F in paper chromatography, M _G in ionophoresis in borate buffer, its resistance to almond β-glucosidase, lack of formation of osazone and the similarity of its stain (aniline hydrogen phthalate spray) to that of sophorose. Peat et al. ⁴ have also described the isolation of a gluco-biose (octaacetate; melting point 166°, [α]_D + 153°), believed to contain the 1 : 2-α-linkage, from a mixture of disaccharides synthesized from glucose by Aspergillus niger. One of us (K. A.) has detected kojibiose in the acid hydrolysate (hydrol) of sweet potato starch which is known to have undergone marked reversion⁵. We now report the isolation of this sugar from hydrol.