Residence time distribution (RTD) of particulate foods in a continuous flow pilot-scale ohmic heater

The residence time distribution (RTD) of a model particulate-fluid mixture (potato in starch solution) in the ohmic heater in a continuous sterilization process was measured using a radio frequency identification (RFID) methodology. The effect of solid concentration and the rotational speed of the agitators on the RTD were studied. The velocity of the fastest particle was 1.62 times the mean product velocity. In general, particle velocity was found to be greater than the product bulk average velocity. Mean particle residence time (MPRT) increased with an increase in the rotational speed of the agitators (P < 0.05), and no particular trend was observed between the MPRT and the solid concentration. The distribution curves E (theta) were skewed to the right suggesting slow moving zones in the system.