Optimization Of Isomaltooligosaccharide Size Distribution By Acceptor Reaction Of Weissella Confusa Dextransucrase And Characterization Of Novel Alpha-(1 -> 2)-Branched Isomaltooligosaccharides

Long-chain isomaltooligosaccharides (IMOs) are promising prebiotics. IMOs were produced by a Weissella confusa dextransucrase via maltose acceptor reaction. The inputs of substrates (i.e., sucrose and maltose, 0.15-1 M) and dextransucrase (1-10 U/g sucrose) were used to control IMO yield and profile. According to response surface modeling, 1 M sucrose and 0.5 M maltose were optimal for the synthesis of longer IMOs, whereas the dextransucrase dosage showed no significant effect. In addition to the principal linear IMOs, a homologous series of minor IMOs were also produced from maltose. As identified by MS '' and NMR spectroscopy, the minor trisaccharide contained an alpha-(1 -> 2)-linked glucosyl residue on the reducing residue of maltose and thus was alpha-D-glucopyranosyl-(1 -> 2)-[alpha-D-glucopyranosyl-(1 -> 4)]-D-glucopyranose (centose). The higher members of the series were probably formed by the attachment of a single unit branch to linear IMOs. This is the first report of such alpha-(1 -> 2)-branched IMOs produced from maltose by a dextransucrase.