Structural Analysis and Synthesis of Oligosaccharides Isolated from Fermented Beverage of Plant Extract

Abstract

Fermented beverage of plant extract was prepared from about fifty kinds of fruits and vegetables. Natural fermentation was conducted by lactic acid bacteria (Leuconostoc spp.) and yeast (Zygosaccharomyces spp. and Pichia spp.). Fourteen kinds of oligosaccharides have been isolated from this beverage; their struc- tures were confirmed by methylation analysis, MALDI-TOF-MS and NMR measurements. In these saccha- rides, five novel oligosaccharides have been found to be constructed by fructose residue of pyranose form, and fructosyl residues of sucrose bond with the -D-galactose and -D-glucose. The characteristics of one of the novel saccharides, O --D-fructopyranosyl-(2↑6)-D-glucopyranose (Fp2-6G) were investigated, and included non-cariogenicity and low digestibility. Furthermore, the unfavorable bacteria, Clostridum perfringens, Es- cherichia coli and Enterococcus faecalis, that produce mutagenic substances did not use the saccharide. The Fp2-6G synthesis activity of crude enzyme of the 5 yeast strains isolated from plant extract was examined us- ing the ABEE-converting method. Fp2-6G synthetic activity was observed only in a reaction mixture using crude enzyme from the Y-1 strain. The Y-1 strain was identified as Pichia spp.