Micro-Heterogeneity and Micro-Rheological Properties of High-Viscosity Barley β-Glucan Solutions Studied by Diffusing Wave Spectroscopy (DWS)

Soluble fiber beta-glucan is one of the key dietary materials in healthy food products known for reducing serum cholesterol levels. The micro-structural heterogeneity and micro-rheology of high-viscosity barley beta-glucan solutions were investigated by the diffusing wave spectroscopy (DWS) technology. By comparing the mean-square displacement (MSD) of the microspheres imbedded in eight concentrations of beta-glucan solutions, we found that the solutions exhibited nearly homogeneous behavior at aecurrency sign0.1 %, but the material showed a clear degree of heterogeneity at aeyen0.25 %. Micro-rheology investigation revealed that beta-glucan solutions displayed nearly perfect viscous behavior at aecurrency sign0.1 %, but the property changed into viscoelastic one at aeyen0.25 %. The magnitude of high-frequency viscoelastic moduli for the 0.25 % - 0.75 % beta-glucan solutions can be characterized by EuroG*Euro ae omega(3/4), which is the semi-flexible polymer behavior. However, the magnitude of high-frequency viscoelastic moduli (EuroG*Euro) for the 1.0 % - 1.25 % beta-glucan solutions is proportional to omega(1/2), which is the flexible polymer behavior. All micro-structural heterogeneity and micro-rheological property shifts occurred in relatively small concentration ranges.