Some properties of xanthan gum in aqueous solutions: effect of temperature and pH

The properties of xanthan gum (XG) aqueous solutions were investigated by using viscometric, electrokinetic and surface tension measurements. The effects of polymer concentration, temperature and pH on the viscosity of the XG solutions were evaluated and discussed. Zeta potential data determined for XG solutions in water in the temperature range of 15–45 °C corroborated with the results obtained from the viscometric investigations suggest the occurence of conformational changes above 36 °C. The activation energy of flow and that associated with the electrophoretic migration of the charged particles were estimated for XG solutions in water. In acid medium, xanthan gum determines a slight decrease of the surface tension of pure water at all investigated temperatures.