Vol. 7, Special Issue 6 (2019)
Ohmic heating, a novel technology for processing of liquid foods: A review
Author(s): Satish Kumar, Ashok Kumar, Sanoj Kumar, Jitendra Kumar and Prem Prakash
Abstract: Ohmic heating is a thermal process in which heat is generated internally by passing alternating electrical current through a body such as a food system, that serves as an electrical resistance; therefore this technology can also be referred as electro-conductive heating, joule heating, electro-heating, electrical resistance heating and direct electrical resistance heating (Sastry, 2008). The main advantage of ohmic heating is the rapid and relatively uniform volumetric heating in which we can use large size heating tubes with lower shear rates and it allows the heating of fragile particles. Electrical conductivity is the main parameter in ohmic heating and for purely liquid foods, the electrical conductivity increases linearly with temperature but in overall it falls as the concentration of solids increases. Proper electric conductance management is essential to successfully apply ohmic heating. During batch heating tests, the temperature difference in the smaller ohmic unit (4.8 cm long) ranges from 1 to 2 ºC and in the larger unit (30.4 cm long) it showed considerable differences in temperature along its axis for different voltage gradients. A wide range of ohmic heating applications have been reported in different products such as sour cherry juice; orange juice; apple, orange, and pineapple juices; grape juice and pomegranate juice. In ohmic heating processing, the effect on the quality and shelf life of apricots in syrup was studied by using a continuous pilot scale ohmic unit which comprises a hopper containing the product, a pump, a control system, a heating column, a holding and cooling tube, a storage tank for recycling, an aseptic tank to store the treated product and an aseptic filler.
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How to cite this article:
Satish Kumar, Ashok Kumar, Sanoj Kumar, Jitendra Kumar and Prem Prakash. Ohmic heating, a novel technology for processing of liquid foods: A review. International Journal of Chemical Studies. 2019; 7(6): 778-782.
