Isolation and characterization of novel heterogeneous branched cyclomalto-oligosaccharides (cyclodextrins) produced by transgalactosylation with α-galactosidase from coffee bean

Transgalactosylated derivatives of cyclomalto-hexaose (αCD), -heptaose (βCD), and -octaose (γCD) were synthesized by α-galactosidase from coffee bean using melibiose as a donor and αCD, βCD or γCD as an acceptor. Mono- and di-O-α-d-galactosylated CDs were isolated and purified by HPLC. Their structures were elucidated by fast-atom bombardment mass spectrometry (FABMS) and 13C NMR spectroscopy. For structural determination of positional isomers of 61,6n-di-O-α-d-galactosyl-CDs, digestion products with cyclodextrin glucanotransferase were analyzed by HPLC and FABMS.