Rheological and light scattering properties of flaxseed polysaccharide aqueous solutions.
Polysaccharides isolated from flaxseed meals using ethanol consisted of a soluble ( approximately 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 ( approximately 17%) of large molecular weight species (1.0 x 10(6)) and a large amount ( approximately 69%) of small molecular weight species (3.1 x 10(5) Da). Dynamic light scattering measurements indicated the presence of very small molecules (hydrodynamic radius approximately 10 nm) and a very large molecular species (hydrodynamic radius in excess of 100 nm); the latter were probably aggregates. The intrinsic viscosity, [eta], 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 approximately 0.018, indicating that the molecules adopted a semi-flexible conformation. This was also indicated by the slope ( approximately 0.56) from the plot of root-mean-square (RMS) radius versus molar mass (M(w)).
Goh
Kelvin K T
KK
Institute of Food, Nutrition and Human Health and Institute of Fundamental Sciences, Massey University, Private Bag 11 222, Palmerston North, New Zealand. K.T.Goh@massey.ac.nz
Pinder
D Neil
DN
Hall
Christopher E
CE
Hemar
Yacine
Y
D002850:Chromatography, Gel; D019597:Flax / Q000737:chemistry*; D008027:Light; D011134:Polysaccharides / Q000737:chemistry*; D012212:Rheology; D012542:Scattering, Radiation; D012996:Solutions; D014783:Viscosity; D014867:Water
D011134:Polysaccharides; D012996:Solutions; D014867:Water