Dielectric study on the dynamics of an aqueous solution of gellan gum

Abstract

In order to make clear the dynamics of water related to the coil-helix and the sol-gel transitions in aqueous solutions of gellan gum, dielectric relaxation measurements of 2.5 and 5.0 wt% gellan gum aqueous solutions in the temperature range between 2.5 and 52.5 °C were performed over a frequency range from 30 Hz to 10 GHz using time-domain reflectometry. The dielectric relaxation peak of water is observed around 10 GHz, and the relaxation curve is well described by the Cole-Cole equation. The parameter for the symmetric distribution of the relaxation time, β, shows different temperature dependences below and above the coil-helix and sol-gel transitions. The conformation of gellan gum molecules affects the variation of the local structure of water.