Hydration kinetics of five bambara seed varieties from Botswana was studied by soaking in water at temperatures 25-100 degrees C in constant-temperature water bath for 0.5-24 h using Peleg equation. Peleg's equation adequately described the hydration characteristics of bambara seeds tinder the experimental condition with the mean relative percentage deviation modulus (E) of less than 10% for each variety. For each variety, Peleg's rate constant K, decreased significantly as the hydration temperature was increased from 25 to 100 degrees C suggesting a corresponding increase in the initial water absorption rate. Peleg capacity constant K(2) increased with increase in temperature (25-75 degrees C) and dropped at 100 degrees C in all varieties, demonstrating that the water absorption rate increased and water absorption capacity decreased with increase in temperature. While an E(a) of 37.83, 39.60, 33.02, and 33.33 kJ/mol was calculated for NTSR, BotR, DipC1, DipC2 bambara seeds, respectively, a lower value of 16.46 kJ/mol was obtained for AS17. The negative values of enthalpy (AH) for all the variety indicate that changes during the hydration of bambara seeds are associated with exothermic and energetically favorable transformation. The higher values of E(a) and free energy of activation (Delta G*) for NTSR, BotR, DipC1, and DipC2 indicate that the seeds experience a large change and hydration was more influenced by temperature. However, the lower value of E(a) and the negative values of entropy of activation (Delta S*) for AS17 indicate that the seeds were more thermally stable and hydration changes was less influenced by temperature. The optimum soaking time for bambara seeds for all the varieties appear to be 6 h at temperature <= 75 degrees C. (c) 2008 Elsevier Ltd. All rights reserved.