Rheological and Light Scattering Properties of Flaxseed Polysaccharide Aqueous Solutions

• Published in: Biomacromolecules Vol. 7; no. 11; pp. 3098 - 3103
• Main Authors: Goh, Kelvin K. T, Pinder, D. Neil, Hall, Christopher E, Hemar, Yacine
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.11.2006
• Subjects: Applied sciences; Chromatography, Gel; Exact sciences and technology; Flax - chemistry; Light; Natural polymers; Physicochemistry of polymers; Polysaccharides - chemistry; Rheology; Scattering, Radiation; Solutions; Starch and polysaccharides; Viscosity; Water; Molecular rigidity; Hydrodynamic radius; Light scattering; Intrinsic viscosity; Linseed; Radius of gyration; Experimental study; Molecular weight property relation; Oilseed cake; Dynamical scattering; Plant origin; Oside polymer; Aqueous solution; Conformation
• ISSN: 1525-7797; 1526-4602
• DOI: 10.1021/bm060577u

Polysaccharides isolated from flaxseed meals using ethanol consisted of a soluble (∼7.5% w/w) and an insoluble fraction (2% w/w). The soluble fraction was dialyzed in various salt concentrations and characterized using viscometry and light scattering techniques. Observations using a size-exclusion column coupled to a multiangle laser light scattering (SEC-MALLS) revealed three molecular weight fractions consisting of a small amount (∼17%) of large molecular weight species (1.0 × 106) and a large amount (∼69%) of small molecular weight species (3.1 × 105 Da). Dynamic light scattering measurements indicated the presence of very small molecules (hydrodynamic radius ≈ 10 nm) and a very large molecular species (hydrodynamic radius in excess of 100 nm); the latter were probably aggregates. The intrinsic viscosity, [η], of the polysaccharide in Milli-Q water was 1030 ± 20 mL/g. The viscosity was due largely to the large molecular weight species since viscosity is influenced by the hydrodynamic volume of molecules in solution. The Smidsrod parameter B obtained was ∼0.018, indicating that the molecules adopted a semi-flexible conformation. This was also indicated by the slope (∼0.56) from the plot of root-mean-square (RMS) radius versus molar mass (M w).