Micro-rheological and micro-heterogeneity properties of soluble glutinous rice starch (SGRS) solutions using diffusing wave spectroscopy (DWS)

Authors: Xu, Jingyuan - James; Liu, Sean; Boddu, Veera

Submitted to: Journal of Food Measurement and Characterization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/24/2019
Publication Date: 7/10/2019
Citation: Xu, J., Liu, S.X., Boddu, V.M. 2019. Micro-rheological and micro-heterogeneity properties of soluble glutinous rice starch (SGRS) solutions studied by diffusing wave spectroscopy (DWS). Journal of Food Measurement and Characterization. 13:2822-2827. https://doi.org/10.1007/s11694-019-00202-8.
DOI: https://doi.org/10.1007/s11694-019-00202-8

Interpretive Summary: Soluble glutinous rice starch (SGRS) is widely used in the food industry, and has better binding characteristics than dextrin. However, the properties and the structure-function relationship of SGRS are still not clearly understood. This paper examines some of the physical properties of the SGRS. Using a technology named Diffusion Wave Spectroscopy (DWS) as well as mechanical rheometry, we studied the flow behavior and micro-rheology of SGRS. The results of this research gave us insight into the physical properties of SGRS. It has also shown that the technique of DWS is powerful for studying the properties of food systems.

Technical Abstract: As a natural biopolymer, soluble glutinous rice starch (SGRS) is widely used in the food industry; and has better binding characteristics than dextrin. The micro-structural heterogeneity and micro-rheology of SGRS solutions were investigated by the novel technique diffusion wave spectroscopy (DWS). By comparing the mean-square displacement (MSD) of the microbeads imbedded in six concentrations of SGRS solutions, we found that the solutions exhibited nearly homogeneous behavior at less than or equal to 0.5%, but the material displayed a clear degree of heterogeneity at >1%. Micro-rheology investigation revealed that SGRS solutions showed nearly perfect viscous behavior at less than or equal to 0.5%, but the property changed into a viscoelastic one at >1%. The magnitude of high-frequency viscoelastic moduli for the 3-5% SGRS solutions is proportional to (omega) power (3/4), which is the semi-flexible polymer behavior. However, the magnitude of high-frequency viscoelastic moduli for the 7-10% SGRS solutions is proportional to (omega) power (1/2), which is the flexible polymer behavior. All micro-structural heterogeneity and micro-rheological property shifts occurred in relatively small concentration ranges.