A study on degradation kinetics of thiamine in red gram splits (Cajanus cajan L.)

The kinetics of thiamine degradation in red gram splits (Cajanus cajan L.) as well as in pure thiamine solutions (at initial concentrations present in red gram splits) have been studied at pH 4.5, 5.5 and 6.5, over a temperature range of 50–120 °C (steady state temperature process). The degradation kinetics of thiamine, in normal open pan cooking, pressure-cooking and a newly developed and patented fuel-efficient ‘eco- cooker’, have also been studied (unsteady state heating process). The thiamine degradation was observed to follow first order kinetics where the rate constant increased with an increase in the temperature. The temperature dependence of degradation was adequately modelled by the Arrhenius equation. A mathematical model has been developed, using the steady state kinetic parameters obtained, to predict the losses of thiamine from the time-temperature data of the unsteady state heating/cooking process. The results obtained indicate a thiamine degradation of similar magnitude in all the three modes of cooking used in the study.