Effect of barley β-glucan molecular size and level on wheat dough rheological properties

The effect of adding low (10(5) Da) or high (2.03 x 10(5) Da) molecular weight barley beta-glucans in two wheat flours of different breadmaking quality were studied. Mechanical spectra and creep-recovery analysis data within (low stress) and out (high stress) of the linear viscoelastic region were obtained. The results revealed that the theological behavior of beta-glucan-enriched doughs depend on concentration and molecular weight of the polysaccharide as well as on the flour type used. Addition of beta-glucan increased the G' values of the good breadmaking quality flour doughs, whereas decreased the G' of the poor quality wheat cultivar. Supplementation with beta-glucans increased the resistance to deformation, flowability and elasticity of the doughs under low stress. Significant correlations between frequency sweep and creep-recovery parameters of optimally developed doughs from both flours were found. The addition of beta-glucan in the dough recipe of the poor breadmaking wheat flour may result in similar theological responses to those obtained from a non-fortified good breadmaking quality wheat flour. (C) 2008 Published by Elsevier Ltd.