Dielectric and thermophysical properties of different beef meat blends over a temperature range of-18 to+10 °C

Dielectric and thermophysical properties of three different beef meat blends (lean, fat and 50:50 mixture) were evaluated over a range of temperatures from - 18 to + 10 degrees C. In the region of thawing (-3 to - 1 degrees C), dielectric constant (epsilon '') and dielectric loss factor (epsilon') values for radio frequency (RF) and microwave (MW) were significantly higher (P < 0.05) than at other measured temperatures for the three blends. In the same region, thermal conductivity (k), specific heat (c) and thermal diffusivity (alpha) also showed significant changes (P < 0.05). k and alpha values were significantly lower, while c values were significantly higher in this region than at other measured temperatures for the three blends. RF (27.12 MHz) vs. MW (896 and 2450 MHz) frequencies had an important effect (P < 0.05) on the measured dielectric properties of the beef meat blends, with a general tendency towards higher values at the RF frequency. Finally, composition significantly influenced (P < 0.05) the measured dielectric and thermophysical properties at all temperatures used. These data are of potential value to food technologists in the context of rapid defrosting of meat products. (C) 2007 Elsevier Ltd. All rights reserved.