Effect of pH of Dispersion on Some Physicochemical Properties of Regenerated Cashew Gum

Abstract

Cashew gum is the exudate obtained from the bark of the tree Anacardium occidentale. The gum has been modified by regenerating the native cashew gum from buffer solutions of different pH. The regenerated cashew gum was prepared by dispersing processed native cashew gum in buffer solution of different pH and recovered by precipitating with acetone. The physicochemical properties of the gums obtained were evaluated by determining their moisture sorption, swelling and thermal properties at similar temperature conditions. The isothermal moisture sorption and maximum swelling time increased with increase in the pH of buffer solutions used for dispersing the native cashew gum. The various DSC thermal transitions shown in the thermographs of the gums regenerated from distilled water were similar to those of the gums regenerated from buffer solutions of pH 7 and 2.5 but different from those regenerated from pH 10 buffer dispersion. Generally,samples of cashew gum regenerated from the dispersions of the different pHs showed characteristically different equilibrium moisture sorption, maximum swelling ratio and thermal properties.