Kappa carrageenan/acrylic acid graft-copolymers (kC-g-AAc) were prepared by using gamma-radiation. The prepared graft-copolymer was acidified to convert the sulfate group (-OSO3-) in kappa carrageenan into sulfuric group (-OSO3H) to be used as catalytic reagent for sucrose hydrolysis. The hydrolysis of sucrose to glucose and fructose by kC-g-AAc copolymers was investigated. The kinetics of the reaction was determined for various kC/AAc compositions and the reaction rate constants were obtained in a temperature range of 40-70 degrees C. The catalytic activity of the copolymers was found to be dependent on the reaction temperature and kC/AAc compositions, it increased with high reaction temperature and enhanced kC content (high -OSO3H groups) in the feed solution. The obtained results suggest that the prepared kC-g-AAc copolymers considered as catalytic reagent for sugar hydrolysis. (C) 2008 Elsevier B.V. All rights reserved.