Electroconductive thawing by liquid contact

Summary A method of rapid thawing, especially suitable for large frozen products is proposed. The method is based on electroconductive heating of the frozen product immersed in a liquid and positioned between two electrodes having no direct contact with the piece. The electrical current passing through the product generates internal heat, thus considerably shortening thawing time. Furthermore, in this process a low surface temperature can be maintained at any desired level, by circulating cooling water over the product, without affecting thawing rates. Local overheating within the product is avoided by either controlling current density or by programming various combination of pulse duration and frequency. For example, it took 160 min to thaw a −20°C frozen cylindrical (17 cm ø× 33 cm) meat chunk where the temperature at the surface and at the thawed part were maintained below 7 and 2WC, respectively. In comparison, 450 min were needed to thaw a similar frozen sample immersed in a 20°C stirred water.