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°C. In the region of thawing (-3 to -1°C), dielectric constant (ε') and dielectric loss factor (ε') 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 (α) also showed significant changes (P<0.05). k and α values were significantly lower, while c values were significantly higher in this region than at other measured temperatures for the three blends. RF (27.12MHz) vs. MW (896 and 2450MHz) 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.