Production of Rubusoside Derivatives by Transgalactosylation of Various β-Galactosidases

Abstract

Rubusoside derivatives by transgalactosylation of various β-galactosidases were isolated and their structures were analyzed. Escherichia coli β-galactosidase produced mainly 13-O-β-D-glucosyl-19-O-[β-D-galactosyl-(1→6)-β-D-glucosyl]-steviol (RGal-2). Bacillus circulans β-galactosidase produced mainly 13-O-β-D-glucosyl-19-O-[β-D-galactosyl-(1→4)-β-D-glucosyl]-steviol (RGal-la) in the early stage of the reaction and then produced 13-O-[β-D-galactosyl-(1→4)-β-D-glucosyl]-19-O-β-D-glucosyl-steviol (RGal-1b). With decreasing the amount of these products (RGal-la and RGal-1b), RGal-2 was produced.