The effect of metal ion content on the viscosity of gum ghatti

Abstract

Abstract Cold water extraction of gum ghatti gives a soluble gum and an insoluble gel. The two fractions were shown by potentiometric titration to have the same acid equivalent weight and to be largely in the salt form, with less than 10% in the free acid form. Quantitative analysis of the two fractions for metal ion content showed that the gel fraction was largely a calcium salt. The soluble fraction contains calcium, potassium, sodium, and magnesium. Precipitation of the calcium ions reduces the viscosity but the original viscosity is not restored by addition of calcium ions.