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United States Department of Agriculture

Agricultural Research Service

Title: Microstructure and Microrheology of Wheat Gliadin Suspensions Studied by Multiple-Particle Tracking

Authors
item Xu, Jingyuan
item Tseng, Yiider - JOHNS HOPKINS UNIV
item Carriere, Craig
item Wirtz, Denis - JOHNS HOPKINS UNIV

Submitted to: Biomacromolecules
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 29, 2001
Publication Date: N/A

Interpretive Summary: Wheat proteins represent an important commodity group. Due to the depressed price structure for wheat, new value-added applications need to be found. In order to develop new applications for wheat proteins the relationships between wheat and protein structure and its physical properties need to be established. The research reported in this paper utilizes a novel method to establish some of these relationships. This work is part of ongoing efforts to establish a database for the structure-property performance of wheat proteins and the development of new application areas.

Technical Abstract: By monitoring the thermally driven displacements of imbedded polystyrene microspheres via video fluorescence microscopy, we quantified the microstructural and micromechanical heterogeneities of wheat gliadin suspensions. We found that the degree of heterogeneity of the suspensions, as measured by the width and skewness of the microspheres' mean squared displacement (MSD) distribution, increased dramatically over a narrow range of gliadin concentrations. The ensemble averaged MSD of a 250 mg/ml gliadin suspension adopted a power law behavior, which scaled with time. This behavior was also observed for a homogenous aqueous glycerol solution; however, the shape of the MSD distribution for the gliadin suspension was wider and more asymmetric than for glycerol. For increasing concentrations of gliadin, the ensemble averaged MSD rapidly displayed a plateau at small time scales, the MSD distribution became wider and more asymmetric, and the local viscoelastic moduli, extracted from multiple particle-tracking measurements, showed an increasingly wider range.

Last Modified: 10/25/2014
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