Structural analysis of water-soluble and -insoluble β-glucans of whole-grain oats and barley

Water-soluble and water-insoluble (1 --> 3),(1 --> 4)-beta-D-glucans were isolated from whole-grain oats and barley and digested with lichenase. The oligosaccharides thus produced were analysed using anion-exchange chromatography with pulse-amperometric detection (HPAEC-PAD). The FT-IR, H-1 NMR and solid-state C-13 CP-MAS NMR spectra of the beta-glucans were also measured. Analyses of the ratio of oligosaccharides with degrees of polymerisation 3 and 4 (DP3:DP4) showed small structural differences between oats and barley and between the water-soluble and water-insoluble (beta-glucans. The molar masses analysed using the SEC-HPLC method were 500,000 g/mol for the soluble beta-glucans of both oats and barley and < 200,000 g/mol for the insoluble beta-glucans. No differences were found in the FT-IR and NMR spectra. Published by Elsevier Ltd.