Radio-frequency heating of heterogeneous food - Meat lasagna

This research studied feasibility of using radio-frequency (RF) energy to thermally process highly heterogeneous foods in large containers as shelf-stable products. Meat lasagna was selected as the food for the study. Dielectric properties of beef, mozzarella cheese, noodles, and sauce were determined between 1 and 1800 MHz and from 20 to 121 degrees C. A 6-kW 27-MHz RF system was used to sterilize packaged meat lasagna in large polymeric containers (295 x 253 x 42 mm) during which the temperature of different components were monitored. Computer simulations were also conducted to evaluate the influence of the dielectric properties of each food component on the electric field distribution and heating pattern during RF heating. The measurements indicated small temperature differences in beef meatballs, mozzarella cheese and sauce when they were properly distributed between layers of noodles. Simulation results suggested that in spite of large differences in electric field intensities in different food components, adequate heat transfer reduced differential heating. Thus, RF heating can be used to process pre-packaged heterogeneous foods and retain product quality. (C) 2011 Elsevier Ltd. All rights reserved.