Micro - heterogeneity and micro - rheological properties of high - viscosity oat b - glucan solutions q

Soluble fibre b-glucan is one of the key dietary materials in the healthy food products known for reducing serum cholesterol levels. The micro-structural heterogeneity and micro-rheology of high-viscosity oat b-glucan solutions were investigated by monitoring the thermally driven displacements of well-dispersed microspheres via video fluorescence microscopy. By comparing the distribution of the timedependent mean-square displacement (MSD) and ensemble-averaged MSD of polystyrene microspheres imbedded in four concentrations of b-glucan solutions, we found that the solutions exhibited perfectly homogeneous behaviour at 61%, but showed a certain degree of heterogeneity at 2%. Micro-rheology investigation revealed that b-glucan solutions displayed nearly perfect viscous behaviour at 61%, but the property changed into viscoelastic at 2%. Both micro-structural heterogeneity and micro-rheological property shifts occurred over a small concentration range, between 1% and 2%, of b-glucan. Published by Elsevier Ltd.