Study of microwave cooking of legumes with excess water: The case of chickpeas

Abstract

In the context of the agro-ecological transition towards sustainable systems, legumes are a real opportunity in terms of agronomy and nutrition. The development of vegetable seed consumption is currently hampered by the problem of the long hydration and cooking stages of current processes. Low CO2 emission processes, such as microwave treatment, are preferred. The efficiency of these processes relies on the transformation of the energy contained in an electromagnetic wave into heat within materials with dielectric losses. The objective of the presented work is to study the evolution of the characteristics of leguminous seeds during the operation of cooking in excess of water by microwave treatment. Kinetics of texture modification and mass gain of the seeds were performed for three different levels of microwave power (between 400 and 1200 W) and compared to hot plate cooking. Empirical models by multi-parameter equations were proposed and validated by a 1000 W treatment. The results show that the evolution of hardness and mass gain is strongly related to the evolution of mass transfer coupled with volume heat transfer phenomena, specific to electromagnetic wave heating. Two different profiles of hardness and mass gain were observed depending on the type and intensity of the treatment. This work is a preliminary experimental study allowing to express hypotheses, which will be validated later by a more thorough study.