Studies on Modified Tamarind Kernel Powder. Part I: Preparation and Physicochemical Properties of Sodium Salt of Carboxymethyl Derivatives

Abstract Sodium salt of 0‐carboxymethyl derivatives of tamarind kernel powder (TKP), at different levels of substitution, was prepared in iso‐propanol medium. The derivatives were characterised by degree of substitution (DS), intrinsic viscosity and elution profile (GPC). Alkaline solutions, purified by alcohol precipitation showed higher intrinsic viscosity due to an alkali soluble fraction. Solution properties of the derivatives as a function of DS were found to be affected both by the substituent groups as well as by the alkali used for derivatization. Swelling power, solubility and tolerance to organic solvents of the derivatives increased with increasing carboxymethylation. The interaction properties of TKP with calcium chloride and sodium tetraborate were found to be reversed upon carboxymethylation.