The kinetics of riboflavin degradation in spinach (Spinacea oleracea L.) as well as in pure riboflavin solutions at initial contentrations present in spinach was studied over a temperature range of 50-120 degreesC (steady state temperature process), and during normal open pan cooking, pressure cooking and a newly developed and patented fuel-efficient 'EcoCooker' has also been studied (unsteady state heating process). The degradation followed first order kinetics. where the rate constant increased with an increase in the temperature. The temperature dependence of degradation was adequately modeled by Arrhenius equation. A mathematical model has been developed using the steady state kinetic parameters obtained to predict the losses of riboflavin from the time-temperature data of the unsteady state heating/cooking process. The results obtained indicate a riboflavin degradation of similar magnitude in all! the three modes of cooking used in the study. (C) 2004 Elsevier Ltd. All rights reserved.