Ohmic Heating for Food Products- A Review

Ohmic heating is a novel technology for food processing. This review paper summarizes the research progress and application in ohmic heating technology used in food processing. Ohmic heating is an electrical resistance heating method for the heat treatment of food products. When electric current passes through the food, the food heats up because of its internal electrical resistance. In this process heating rate depends upon the electrical conductivity and field strength. By this method a product undergoes a minimum structural damage, retain its nutritional value. This technique gives excellent processed quality products in minimum operating time. In this method electrical energy is converted into thermal energy. This is an uniform and rapid heating method. Electrical conductivity of food plays an important role in the ohmic heating process. Ohmic heating is good for liquid products, milk desserts, yoghurts, eggs, fruit juices, condiments, gelatine, wine, and hydrocolloids, etc which have electrical conductivity greater than 0.05 S/m. This method can be used in several sectors of food processing such as thawing process, blanching, sterilization, pasteurization, enzyme inactivation, expression, extraction, desalination and waste water treatment, rice bran stabilization, tofu making process, semi meat ball cooking and drying process etc.