Trichilia Roka Gum: Rheological Analysis

Trichilia roka gum was purified and analyzed and subjected to physicochemical, spectroscopic and rheological analysis. Results obtained from physicochemical analysis indicated that the gum is mildly acidic, ionic and exhibited properties that are closely related to most useful food and pharmaceutical gums. The gum has rich content of fibre, major elemental ions and other useful minerals. GCMS and XRF studies on the gum also revealed that the gum has several industrially useful minerals. The viscosity of the gum is found to be significantly affected by concentration, temperature, pH and concentration of electrolyte. Calculated value of intrinsic viscosity from Kraemer and Huggins plots were 4.67 to 8.57 dl/g while those obtained from Tanglertpaibul
1 shows the photographs of the crude and purified gum. After purification, the percentage yield obtained for the gum was 74 % and the swelling capacity was 15 times its original value. TR gum is whitish yellow in colour and exhibited bland and sour taste and is mildly acidic. TR gum is soluble in cold and hot water but insoluble in acetone, chloroform and ethanol indicating that the gum is ionic. The solubility of the gum in water decreases with increase in temperature, indicating that the dissolution reaction of the gum is exothermic because the heat given off during the dissolution of the gum is more than the heat required to break the molecules of the gums apart (Eddy et al.,
This can be achieved by using a linear regression called the graphic double extrapolation procedure (GDEP). This equation has also beenfound to be closely related to the Huggins equation and can be written as follows:
_sp/C = [] + k^' []^2 C 4
From equation 4, a plot of _sp/C versus C should be linear with intercept equals to the intrinsic viscosity. Fig. 8presents plots for the variation of _sp/C with C (Huggins’ plots). The intrinsic viscosities, Huggins constants and degree of linearity (R2 = 0.9807) were deduced from the plots. The results obtained indicate that the values of R2 (0.9was very close to unity indicating excellent correlation and hence better fitness of the data to the Huggins model. The Huggins constants deduced from the plots were found to be 0.0749 while calculated value of []was 8.57 dl/g. According to Higiroet al. (2007), theoretical values of k’ are expected to be between 0.3 and 0.8 and that values larger than unity imply polymer-polymer aggregation. The value obtained from this study fall below this range, indicating that molecular