Ohmic heating for tropical food processing : f experimental studies on heating and nutrition effects.

Abstract

Ohmic heating of foods is a novel food processing operation which directly utilizes electricity as the major heat source, and can be termed as an electroheat technique. The heat effect is achieved by passing an electric current through the product to be heated, the passage of current through the material obeys Ohm's law and depending upon the resistance offered by the media, heat is generated. If the objective is only heat generation, it matters little whether DC or AC is used, however, the use of AC can eliminate electrolysis. Electrolysis of food is obviously undesirable and so ohmic heaters are operated using an AC supply. Little work has been carried out with regard to this process and that it is only recently research has been started in UK, USA and France. Ohmic heating offers several important advantages over conventional food processing. It is possible to apply the technique to process many types of food materials. Some of these are beverage, dairy and vegetable products etc. Results of studies conducted on heating profiles and nutrient retention are presented. Initially a detailed picture of current fruits and vegetable production and associated problems are presented as this provides the essential back drop to this study. Basic nutrition studies have revealed some new information. Nutrition studies conducted has been for the first time and is of major importance.