Design, manufacture and performance evaluation of a batch ohmic heating system

The present work was undertaken with an objective to study the design, development and construction and performance evaluation of a batch ohmic heating system. Direct ohmic heating (Joule’s heating) is a technology to warm up the food using an electric energy where electric current is passed through a material which gets heated by virtue of its electrical resistance. In this study, firstly new batch ohmic heating containing a static cell (200-mm-long Teflon cylinder with 94 mm diameter at a constant voltage gradient of 15 V/cm) was developed and constructed. To evaluate the performance of this heating unit various food systems was used, i.e. sodium chloride solutions (concentrations : 0.2 and 0.6% w/v), starch solutions (2 and 5% w/v) and 0.5% w/v NaCl, a two-phase food systems (5% starch, 0.5% w/v NaCl and oil (1% and 10% w/v). Heating rates for previously named food systems were determined by tracking and recording the temperature profiles for a given time intervals. The data indicates the heating up rate increases with increasing concentrations of starch and salt but decreases with increasing oil in food.