Extraction and functional properties of barley β-glucan as affected by temperature and pH

Barley is high in beta-glucan, a soluble fiber component. Effects of extraction temperature (40 55 C) and pH (7.0 10.0) on recovery, purity and functional properties of beta-glucan were investigated on whole Condor barley flour. At pH 7.0, 8.0 and 55 degrees C, 86.5% of the beta-glucan in the feed flour was recovered in the gum product with 89.1% (d.w.b.) purity. beta-Glucan content increased (p<0.05) with temperature but not with pH. Apparent viscosity of 1% (w/v) dispersions of beta-glucan gum from pH 7.0 increased (p<0.05) with extraction temperature at constant shear rate and viscosity decreased slightly with increasing shear rate. Whippability and foam stability of gums from pH 8.0 and 45 degrees C were maximum. Emulsions prepared with beta-glucan gum from pH 7.0 and 55@c were 63% stable after centrifugation. Barley beta-glucan shows great potential as a thickener or stabilizer.