Comparative study of ohmic vacuum, ohmic, and conventional-vacuum heating methods on the quality of tomato concentrate

Due to the high energy consumption of heating in the conventional processing methods, energy efficient systems are demanded for thermal concentration of juices. Ohmic heating is an emerging technology and a very promising in food industries. Comparing with conventional heating processes, ohmic heating can save energy and provide a rapid and uniform heating of pumpable food, resulting a product with a higher quality. The results showed that vacuum coupled with ohmic heating had a significant effect on quality. One of the keys to reducing the thermal damage to products during manufacture is the shortening of the heating time and reducing the boiling point, ohmic-vacuum heating required a lower time and boil at lower temperature, thereby is more advisable for thermal processing from the point of view of energy saving and quality aspects.