Design and Development of Continuous Ohmic Heater for Milk and Its Performance Study

Present study aimed for the design and development of a continuous ohmic heating system for heating of milk. The holding capacity of the designed heater was 8.24 litre and had a 'tube in tube' type arrangement. The heat transfer area of the ohmic heater was increased by employing two stages, consisting of SS-316 pipes. Process was controlled by using an electrical panel equipped with all the required electrical components. The designed ohmic heater for milk was optimized for heating of milk temperature up to 73°C. Efficient heating of milk was heated at optimized conditions of 137.7 V (stage-1) and 72.2V(stage-2) with 1.5 l/min flowrate. The average heating rate for milk 4.6˚C/min. At optimized conditions, system performance co-efficient was found to be 86.95. The milk heated using ohmic heater showed no significant difference in the composition and sensory attributes when compared to the conventional heating method. Moreover, the alkaline phosphatase test was also parallel to the thermal heating system and milk was highly acceptable by the sensory panel and cost is considerably lower than the thermal system.