Abstract: Tamarind gum as the raw material was studied for the preparation of carboxymethyl tamarind gum using ethanol as solvent. The degree of substitution (DS) and total extent of etherification were determined by variables such as concentration of ethanol, chloroacetic acid as well as alkalization reaction temperature and time,sodium hydroxide, sodium hydroxide and chloroacetic acid molar ratio as well as etherification reaction temperature and time. The optimum conditions for preparing carboxymethyl tamarind gum were got through orthogonal experiments.The effectiveness of the treatments was evaluated by means of infrared spectroscopy. The results indicated that the degree of substitution of tamarind gum which was modified can reach more than 0.5,and by the analysis of infrared spectrum, the structure of the gum was successfully accessed the carboxymethyl groups, then the water solubility and viscosity stability of carboxymethyl tamarind gum had a significant improvement.

Key words: tamarind gum, carboxymethylation, degree of substitution, characterization