Kinetics on colour changes in rice due to parboiling

Paddy (IR 20 variety) was parboiled by soaking at 70 degrees C for 3 it followed by steaming at different pressures (101-304 kPa, absolute pressure) for up to 60 min. The colour variables determined were Hunter L,a,b-values, chroma and total colour difference for the rice samples. Response surfaces for these colour variables against time and pressure of parboiling were developed. Most of the colour changes followed zero order kinetics. The activation energies for chroma and total colour difference were 22.1 and 11.1 kJ mol(-1), respectively. The colour development due to parboiling was minimum at low steaming pressure and short times. Copyright (C) 1996 Elsevier Science.