Gelling temperatures of high acyl gellan as affected by monovalent and divalent cations with dynamic rheological analysis

The effects of Na+, K+, Ca++ and Mg++ cations on the sol-gel transitions of high acyl (HA) gellan dispersions were investigated. Gelling temperatures of 1% HA gellan dispersions containing selected cations (monovalent cations, 10-200 mM; divalent cations, 2-80 mM) were determined using dynamic rheological analysis. Gelling temperatures increased with cation concentrations. Divalent cations exhibited greater effects on the gelling temperature than equivalent concentrations of monovalent cations, but the effects between the two different types of divalent cations or the two different monovalent cations were not significantly different. An equation based upon the assumption that the effects of cations on gelling temperatures were additive fitted well with the experimental data (R-2 = 0.98, standard error of prediction = 0.58 degreesC). (C) 2003 Elsevier Ltd. All rights reserved.