Performance evaluation of a continuous type ohmic heating unit on watermelon juice

Abstract

Performance evaluation of developed continuous type ohmic heating unit with done by response surface methodology according to Box-Behnken Design for watermelon juice. The low and high levels of the variables were 40 and 50 Hertz for frequency of power supply; 25 and 35 V for applied voltage and 12 and 24lphfor capacity. Response studied was system performance coefficient (SPC). It was found that effects of frequency, voltage and capacity were significant on SPC. Optimum conditions (desirability = 0.825) obtained by numerical optimization were processing time- 5.75 min, Voltage- 75V and product thickness – 14.4 mm to achieve maximum SPC. Corresponding to the optimum conditions, the predicted value for frequency were 42 Hertz, applied voltage 30 V and flow rate 24 lphin order to obtain specific performance coefficient (SPC) of 76.8%