A study on the degradation kinetics of visual green colour in spinach ( Spinacea oleracea L.) and the effect of salt therein

Abstract

The effect of salt on the degradation of visual green colour ‘− a’ in spinach puree ( Spinacea oleracea L.) over a temperature range of 50–120 °C (steady state temperature process) as well as under conditions of normal open pan cooking, pressure-cooking and a newly developed and patented fuel-efficient EcoCooker has been studied (unsteady state heating process). The degradation of visual green colour as measured by ‘− a’ value followed a 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 green colour from the time–temperature data of the unsteady state heating/processing method. The results obtained indicate a protective effect of salt on the degradation of visual green colour.