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The dielectric properties of 15 vegetables and fruits were measured at 2450MHz from 5 to 130 8C. Equations were developed as a function of temperature, ash, and either moisture content or water activity, and compared to literature equations. Dielectric constant of vegetables and fruits decreased with temperature and ash content. However, ash was not a factor in the equations produced separately for fruits. Dielectric loss factor changed quadrically with increasing temperature: first decreasing and then increasing. This transition temperature decreased with ash content. Ash increased the dielectric loss factor. Garlic and potato gave unusual results, which could be explained by the behavior of solutions of inulin and potato starch, respectively.

The dielectric properties of 19 different ham samples with different moisture (38.2% to 68.9%) and ash contents (1.78% to 6.80%) were measured at -35 to 70 °C at 2450MHz. Equations were developed as a function of temperature, moisture, and ash, and compared to literature equations. The dielectric constant decreased with ash content and increased with moisture content. It increased instead of decreasing with temperature. The dielectric loss factor increased with moisture content for moisture contents lower than 60.7%, then decreased for higher moisture contents. Ash content and temperature increased dielectric loss factor. Frozen samples had low dielectric activity that was increased by ash content above -20 to -10 °C.

The dielectric properties of cod, perch, salmon, chicken breast, chicken thigh and beef were measured at 15 to 65 degrees C at 2450 MHz. The samples covered a moisture range of 68.9-81.2% and ash range of 0.96-1.20%. Equations were developed as a function of temperature, moisture, and ash, and compared to literature equations. The dielectric constant decreased with temperature and increased with moisture content. It was not affected by ash content. The dielectric loss factor increased with moisture content for moisture contents lower than 74.9%, then decreased for higher moisture contents. The dielectric-loss factor was quadratically related to temperature, decreasing to 30.2 degrees C then increasing. The dielectric loss factor increased with ash content. The effect of moisture content and temperature on the dielectric loss factor in the literature is reviewed to explain these results.

The dielectric properties of turkey meat at water activities of 0.84 to 0.98 were measured at 2450 and 915MHz. Equations were developed as a function of temperature, moisture, water activity, and ash, and compared to literature equations. Unexpected results were: as the water activity decreased or ash increased, the dielectric constant increased with temperature, and dielectric loss factor of reduced moisture samples was determined by moisture not ash. It is theorized that the effect of temperature on dielectric constant is a function of the ratio of bound to free water. Glycerol did not affect the dielectric properties, while lactic acid decreases them by promoting water loss during protein denaturation.