KINETICS OF TAMARIND SEED HYDRATION

The kinetics of hydrothermal behaviour of unpunched and punched tamari nd (Tamarindus indica) seeds were determined at different temperatures (25-80 degrees C). The kinetic parameters determined were hydration r ate constant, equilibrium moisture content frequency factor and activa tion energy. Punching of seed increases the hydration rate constant an d the equilibrium moisture content but reduces the activation energy c ompared to unpunched seeds. The hydration rate constant values for the unpunched seeds were 0.13, 0.16, 0.18, 0.31 and 0.38h(-1) at hydratio n temperatures of 25, 35, 50, 65 and 85 degrees C, respectively; the c orresponding values for the punched seeds were 0.37, 0.40, 0.41, 0.43 and 0.52 h(-1). Linear relationships (r greater than or equal to 0.92, p less than or equal to 0.01) were obtained between the rate of moist ure absorption and average moisture content. The equilibrium moisture content also increases linearly (r greater than or equal to 0.95, p le ss than or equal to 0.01) with an increase in hydration temperature. ( C) 1997 Elsevier Science Limited.