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

Author
item Xu, Jingyuan - James
item CHANG, TUNGSUN - JOHNS HOPKINS UNIVERSITY
item Inglett, George
item Kim, Sanghoon
item TSENG, YIIDER - JOHNS HOPKINS UNIVERSITY
item WIRTZ, DENIS - JOHNS HOPKINS UNIVERSITY

Submitted to: Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/11/2006
Publication Date: 11/22/2006
Citation: Xu, J., Chang, T., Inglett, G.E., Kim, S., Tseng, Y., Wirtz, D. 2006. Micro-heterogeneity and micro-rheological properties of high-viscosity oat beta-glucan solutions. Food Chemistry. 103(4):1192-1198.

Interpretive Summary: Heart disease is the leading cause of death in the United States. Many scientific research reports suggest that reducing total and LDL cholesterol concentrations can decrease the risk of heart attack. Soluble fiber beta-glucan is one of the key dietary materials in healthy food products known for reducing serum cholesterol levels. Several new food products containing high amounts of beta-glucan have been invented, and much research has been done with beta-glucan. However, the properties and the structure-function relationship of beta-glucan are still not clearly understood. This paper examines some of the physical properties of one of the high viscosity oat beta-glucans. Using a technology named multiple-particle tracking (MPT), we studied the flow behavior and micro-rheology of beta-glucan. The results of this research give us much more insight into the physical properties of beta-glucan. It is also shown that the technique of MPT is powerful for studying the properties of food systems. This work could benefit food scientists who will develop new food products with beta-glucan.

Technical Abstract: 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 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 the material showed a certain degree of heterogeneity at 2%. A 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 a viscoelastic one at 2%. Both micro-structural heterogeneity and micro-rheological property shifts occurred in a small concentration range, between 1% and 2% of beta-glucan.