Cereal Chem 68:31-39   |  VIEW ARTICLE

Molecular Characterization of Cereal Beta-D-Glucans. Structural Analysis of Oat Beta-D- Glucan and Rapid Structural Evaluation of Beta-D-Glucans from Different Sources by High- Performance Liquid Chromatography of Oligosaccharides Released by Lichenase.

P. J. Wood, J. Weisz, and B. A. Blackwell. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

Oligosaccharides obtained by the action of (1-3),(1-4)-beta-D-glucan-4-glucanohydrolase (lichenase) on the (1-3),(1-4)-beta-D-glucan of oats (oat beta-glucan) were characterized by methylation analysis. The polysaccharide was confirmed as composed mainly of beta-(1-3)-linked cellotriosyl and cellotetraosyl units with a small amount of regions containing 4-8 consecutive (1-4)-linked units. 13C-Nuclear magnetic resonance data confirmed these structural features. The oligosaccharides released by lichenase were analyzed by elution with water from a Bio-Rad HPX-42A high-performance liquid chromatography column with peak detection by an automated orcinol-sulfuric acid reaction, and the ratio of tri- to tetrasaccharide was determined. This ratio defines the major structural repeating units of the cereal (1-3),(1-4)-beta-D- glucans and may be determined without prior purification of polysaccharide. The molar ratio of tri- to tetrasaccharide determined for oats was 2.1 +/- 0.1, for barley 3.2 +/- 0.3, and for wheat 3.5 +/- 0.4. No difference was detected between the beta-D-glucan from oat brans and the whole groat. In addition, the areas or heights of the major tri- and tetrasaccharide reaction products were used for quantitation by calibration with a beta-D-glucan standard.