Abstract

The physicochemical properties, cationic composition and rheological behaviour of exudates from Ficus glumosa were investigated. The gum was found to be mild acidic, ionic and soluble in water, sparingly soluble in ethanoland insoluble in acetone and chloroform. The trend for the decreasing concentration of elements determined in the gum sample is Mg > Ca > Mn > Zn > Fe > Ni > Zn > Cu > Cd > Pb. Rheological properties of the gums have been adequately modeled using Huggins, Kraemer, Arrhenius, Tanglertpaibul and Rao theories. The results indicated that the viscosity of the gum increases with increasing pH and concentration but decreases with increase in temperature. Values of intrinsic viscosity obtained from Huggins and Kraemer plots were similar (11.197). The value of activation energy (E_vis) of the gum studied was found to be 1.915 kJ/mol. The low E_vis values obtained suggests the existence of few inter and intra-interactions between the molecules of the gums within the investigated temperature. F. glumosa gum exudate hence, possesses the potentials to be used as an additive in food and other industries.

Key words: Ficus glumosa, gum, heavy metal, characterization, rheological modeling.