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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/11131

Title: Rheological and microstructural investigation of oat B-glucan isolates varying in molecular weight
Authors: Agbenorhevi, Jacob K.
Kontogiorgos, Vassilis
Kirby, Andrew R.
Morris, Victor J.
Tosh, Susan M.
Keywords: Oat b-glucan
Molecular weight
Rheological properties
Atomic force microscopy
Issue Date: 2011
Publisher: International Journal of Biological Macromolecules
Citation: International Journal of Biological Macromolecules, 49 (2011) 369– 377
Abstract: The rheological properties and microstructure of aqueous oat b -glucan solutions varying in molecular weight were investigated. The structural features and molecular weights (MW) were characterized by 13C NMR spectroscopy and high performance size-exclusion chromatography (HPSEC), respectively. The microstructure of the -glucans dispersions was also examined by atomic force microscopy (AFM). The samples with B-glucan content between 78 and 86% on a dry weight basis had MW, intrinsic viscosity ([ ]) and critical concentration (c*) in the range of 142–2800 × 103 g/mol, 1.7–7.2 dl/g and 0.25–1.10 g/dl, respectively. The flow and viscoelastic behaviour was highly dependent on MW and on the concentration of the -glucans dispersions. Pseudoplastic behaviour was exhibited at high concentrations and Newtonian behaviour was evident at low concentrations. At the same concentration, the viscosity was higher for higher MW samples. The Cox–Merz rule was applicable for the lower molecular weight samples at higher concentrations whereas the high molecular weight sample deviated at concentrations greater than 1.0%, w/v. The mechanical spectra with variation of both MW and concentration were typical of entangled biopolymer solutions. AFM images revealed the formation of clusters or aggregates linked via individual polymer chains scattered heterogeneously throughout the system. The aggregate size increased with the molecular weight of the samples investigated and has been linked to the rheological behaviour of the samples.
Description: An article published by International Journal of Biological Macromolecules, 49 (2011) 369– 377
URI: http://hdl.handle.net/123456789/11131
Appears in Collections:College of Science

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