Isolation and characterization of a novel polysaccharide from seeds of Peltophorum pterocarpum

Peltophorum pterocarpum seeds yielded ∼20% water soluble polysaccharide. The polysaccharide is a galactomannan with mannose:galactose ratio of 4.4:1. The polysaccharide had an intrinsic viscosity of 3.14 dl/g and weight average molecular weight of 2.49 × 105 g/mol. The polysaccharide solutions were non-Newtonian at concentrations above 1%. A double logarithmic plot of the zero shear specific viscosity versus volume concentration gave a coil overlap concentration, c* of 2.6/[η], with slope c1.4 in the dilute regime and c4.3 in the concentrated regime. The experimental data were fitted to different viscosity models with the Martin model giving the best fit. The Cox–Merz empirical rule gave close superimposition of the data from steady shear viscosity η ( γ ˙ ) and complex viscosity η*(ω).