Gellan polymer solution properties: dilute and concentrated regimes

Flow properties of dilute and concentrated gellan polysaccharide solutions were investigated under low and intermediate shear rates, respectively, to study the behavior of the polymer in water. An apparent stiffness parameter , B'-value, was calculated from the low shear intrinsic viscosity data obta ined at various Na+ concentrations. B'-value data suggested that gellan pol ymer chains are partially flexible. Critical concentration, C*, for gellan solutions was found to be 0.064% w/v, under the measurement conditions used . Flow curves as a function of increasing gellan concentration approached p ower-law flow. With decreasing temperature, gellan polymer solutions showed a transition to power-law behavior between 28 and 25 degrees C. This trans ition was attributed to partial gelation of gellan polymer below the transi tion temperature range. (C) 2000 Elsevier Science Ltd. All rights reserved.