Steady and dynamic shear rheological properties of buckwheat starch-galactomannan mixtures.

摘要

Effects of galactomannans (guar gum, tara gum, locust bean gum) on the rheological properties of buckwheat starch pastes under steady and dynamic shear conditions were determined. The power law and Casson models were applied to describe flow behaviour of buckwheat starch and galactomannan mixtures. Values of apparent viscosity ( eta_a,100), consistency index (K) and yield stress ( sigma_oc) for buckwheat starch-galactomannan mixtures were significantly greater than those for the control, indicating that there was high synergism of starch with galactomannans. Magnitudes of storage modulus (G') and loss modulus (G'') for the starch-galactomannan mixtures increased with increasing frequency ( omega). Dynamic moduli (G', G'') and complex viscosity ( eta*) for buckwheat starch-galactomannan mixtures were markedly higher than those of the control.