Deep-fat frying of food: heat and mass transfer, transformations and reactions inside the frying material

Deep-fat frying is a popular process that has been studied essentially to clarify the complex mechanisms of fat decomposition at high temperatures and to assess their effects on human health. The aim of this paper is to show how the application of process engineering methods has recently improved our understanding of the basic principles and mechanisms involved at different scales and different times during the process: pretreatment, frying, and cooling. New results concerning the understanding of the frying process have been obtained as a result of major breakthroughs in on-line instrumentation (heat, steam flux, and local pressure sensors), in the methodology of microstructural and imaging analysis (NMR, MRI, SEM) and in software tools for the simulation of coupled transfer and transport phenomena. Such advances have opened up the way for the creation of a major database of the behavior of various materials and to the development of new tools to control frying operations via final product quality in real conditions. Lastly, this paper promotes an integrated approach to the frying process including various competencies such as those of chemists, engineers, toxicologists, nutritionists, and materials scientists as well as of the catering and industrial sectors.