The oxidative degradation of barley β-glucan in the presence of ascorbic acid or hydrogen peroxide

Cereal beta-glucans are polysaccharides with health benefits that have been linked to their ability to increase luminal viscosity. However, the functional properties of cereal beta-glucans may be diminished by the susceptibility of this polysaccharide to oxidative degradation. In this study, barley beta-glucan was oxidised with hydrogen peroxide or ascorbic acid and the oxidative degradation of beta-glucan was investigated using both asymmetrical flow field-flow fractionation (AsFlFFF) with aqueous solvent and high performance size exclusion chromatography (HPSEC) with LiBr in DMSO as the solvent. Oxidation was shown to cause degradation of beta-glucan, the reaction being faster when oxidised with hydrogen peroxide compared with ascorbic acid. Both HPSEC and AsFlFFF showed comparable results as long as aggregates (only observed in AsFlFFF) were not included in the integration. The compact aggregates observed in oxidised samples suggest oxidation driven interactions between beta-glucan molecules. (C) 2015 Elsevier Ltd. All rights reserved.