Ohmic Heating for Pasteurization Using Electrical Conductivity in Fruit Juices

The ohmic heating, also called Joule heating is employed as pasteurization technique in juices of litchi, mango, guava and aloe vera. It is an advanced heating treatment where heating is homogenous and mainly employed for thermal treatment of food and juices. The temperature ranges from 20 oC - 70 oC at different voltage gradients (7V/cm, 12V/cm, 17V/cm, 22V/cm, 27V/cm) in present study. The observed electrical conductivity showed a linear rising behavior (0.04S/m – 1.73 S/m)with rise in temperature due to ohmic heating and the results indicated that the effect of voltage gradient was statistically significant on the ohmic heating rate (p<0.05). The significant changes were observed in the pH value of juices at room temperature for mango, guava and aloe vera before and after ohmic heating. The value of TSS of the chosen juices does not change significantly due to ohmic heating. The measurements of these parameters during ohmic heating are important in designing of ohmic heaters for commercial applications and food processing industry.