Chemical modification of Cassia occidentalis seed gum:: carbamoylethylation

The seeds of Cassia occidentalis, an annual weed occurring throughout India, is a rich source of galactomannan gum. The gum derived from seed endosperm can be potentially utilized in a number of industries to replace the conventional gums. With a view to utilize the gum for broader applications, carbamoylethylation of C occidentalis seed gum was carried out with acrylamide in presence of sodium hydroxide under different reaction conditions. Variables studied were concentration of sodium hydroxide, acrylamide, gum-solvent ratio, reaction time and temperature. The nitrogen content, carboxyl content and total ether content were determined. The optimum condition for preparing carbamoylethyl C occidentalis seed gum (%N = 2.57) comprised concentration of acrylamide (0.070 mol), sodium hydroxide (0.125 mol), C occidentalis seed gum (0.03 mol) at 30 degrees C for 3 h. Rheological properties of carbamoylethyl C. occidentalis seed gum solution showed non-Newtonian pseudo-plastic behavior, relatively high viscosity, cold water solubility and solution clarity vis-A-vis unmodified C. occidentalis seed gum. (c) 2004 Elsevier Ltd. All rights reserved.