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Title: MICRO-HETEROGENEITY AND MICRO-RHEOLOGICAL PROPERTIES OF BETA-GLUCAN SOLUTIONS

Author
item Xu, Jingyuan - James
item CHANG, T - JOHN'S HOPKINS UNIVERSITY
item Inglett, George
item Kim, Sanghoon
item TSEBG, Y - JOHN'S HOPKINS UNIVERSITY
item WIRTZ, D - JOHN'S HOPKINS UNIVERSITY

Submitted to: Polymer Processing Society
Publication Type: Proceedings
Publication Acceptance Date: 7/6/2006
Publication Date: 7/6/2006
Citation: Xu, J., Chang, T., Inglett, G.E., Kim, S., Tsebg, Y., Wirtz, D. 2006. Micro-heterogeneity and micro-rheological properties of beta-glucan solutions. Polymer Processing Society. p. 291.

Interpretive Summary: Heart disease is the leading cause of death in the United States. Compelling evidence suggests that reducing total and LDL cholesterol concentrations in serum can decrease the risk of heart attack. Many reports show that soluble fibers can lower serum cholesterol levels. Beta-glucan, as a soluble fiber, is one of the major healthy components in food products. Consumption of beta-glucan has been shown to decrease total and LDL cholesterol levels. The mechanism by which beta-glucan reduces cholesterol levels might be related to its viscosity, bile salt binding capacity or fermentability. However, very little is known about its physical properties. In this work, we investigated the micro-structural heterogeneities and micro-rheological properties of beta-glucan solutions using Multiple-Particle Tracking technique.

Technical Abstract: Soluble fiber beta-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 beta-glucan solutions were investigated by monitoring the thermally driven displacements of well-dispersed microspheres via video fluorescence microscopy. By comparing the distribution of the time-dependent mean-square displacement (MSD) and ensemble-averaged MSD of polystyrene microspheres imbedded in four concentrations of beta-glucan solutions, we found that the solutions exhibited perfectly homogeneous behavior at less than or equal to 1%, but showed a certain degree of heterogeneity at 2%. Micro-rheology investigation revealed that beta-glucan solutions displayed nearly perfect viscous behavior at less than or equal to 1%, but the property changed into viscoelastic at 2%. Both micro-structural heterogeneity and micro-rheological property shifts occurred in a small concentration range, between 1% and 2% of beta-glucan.