Ohmic Heating of Foods

Abstract

This chapter reviews all aspects of ohmic heating and considers the process as a green process from two points of view. Firstly, the very rapid heating process minimizes the time available for heat loss from the product and the equipment. Secondly, the direct application of electrical energy to the food ensures that the inefficiencies in energy transfer at each transformation stage in a conventional process are absent. The mechanism of ohmic heating is considered in some detail together with the factors effecting heating rate. There are also some general treatments on the changes induced in a food during ohmic heating (both physical and biochemical) as well as the mechanisms of microbial destruction that may occur during the ohmic process as opposed to the well know thermal destruction. Three sections cover the three main ohmic heating processes, namely, non-preserving heating, ohmic sterilization and ohmic dehydration. This is followed by a lengthy section in which all of the main food categories are assessed from the aspect of ohmic treatment. Finally, there are three further sections that consider the process economics, process control strategies and a review of the extensive work on modeling of ohmic heating.