Study of heating pattern during heat treatment of milk by ohmic heating

Abstract

Ohmic heating is one of the novel thermal techniques that involve the passage of an electrical current through a food product resulting in heat generation. Efforts are being made to apply ohmic heating in heat treatment of milk commercially. In the present study, heating pattern of milk was studied during heat treatment of milk by ohmic heating. Provision was made in the ohmic heating set up to place multiple temperature sensors to determine uniformity of heating in the bulk liquid. Cow milk was heated from 20 to 90 oC using ohmic heating technology. The parameters for study were heating rate, thermal efficiency, temperature distribution and temperature profile. Rapid heating was observed with heating rate of 3.5 oC/min and the thermal efficiency of the ohmic heating unit obtained was 88.8%. Low temperature gradient in the range of 0-1 oC was observed indicating uniform heating of milk by this novel technique.