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|Title: ||Rheological and microstructural investigation of oat B-glucan isolates varying in molecular weight|
|Authors: ||Agbenorhevi, Jacob K.|
Kirby, Andrew R.
Morris, Victor J.
Tosh, Susan M.
|Keywords: ||Oat b-glucan|
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
|Description: ||An article published by International Journal of Biological Macromolecules, 49 (2011) 369– 377|
|Appears in Collections:||College of Science|
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