Saponin glycosides present in a wide variety of plants have the ability to haemolyse red blood cells. They are known to be relatively heat stable. The present study aims at the development of a kinetic model for degradation of saponins in soybean flour (Glycine max.) subjected to a defined set of processing conditions. This study was carried out at isothermal conditions over a temperature range of 80-130 degrees C, and also under nonisothermal conditions in three different cooking methods viz., open pan, pressure cooking and cooking in a recently developed and patented fuel efficient 'EcoCooker'. The degradation of saponins was adequately modeled by the Arrhenius equation. Using the time-temperature data of the nonisothermal heat process and isothermal kinetic rate parameters, a mathematical model has been developed to predict the degradation of saponins in any nonisothermal heating process of known time-temperature profiles. (c) 2005 Elsevier Ltd. All rights reserved.