Flow Model Fitting and Dynamical Viscoelasticity Analysis of Fenugreek Gum Solutions

Abstract:

The flow and viscoelastic behavior were measured by steady-shear and small-amplitude oscillatory experiments at 25 ℃，respectively. The aim of this paper was to provide meaningful guidance for Fenugreek Gum＇s application in various areas by the rheology analysis. The results showed that FG aqueous solutions exhibited an initial shear-thicking behavior，followed by a shear-thinning behavior above a critical value of shear rate，suggesting a non-Newtonian fluid characteristic. The experimental data were evaluated by the Herschel-Bulkey and Carreau models，results were founded to be well correlated to the Carreau model with a high R2. The hysteresis loop represented a certain thixotropic property of FG solutions，and showed concentration dependence. However，FG solutions at a concentration less than 0.35% showed a negative value of thixotropic loop area，suggesting the structural breakdown and no recovery was measured in the corresponding experiment. The dynamical viscoelastic properties of FG aqueous solutions showed the storage and loss modulus increased with the increase of angular frequency and FG concentrations，and decreased with the increase of temperatures. In addition，the FG solutions exhibited a solid，elastic-like behaviour，while FG at a concentration of 0.1% w/w exhibited a transition from a fiuid-like to gel-like structure.