Analysis of dielectric properties of rice vinegar and sake

The objectives of this study were to determine the dielectric properties of rice vinegar and sake (rice wine) in the 0.3 to 3 GHz frequency range at temperatures from 5°C to 70°C. Dielectric properties of both liquids were analyzed theoretically with the modified Cole-Cole relation including ionic conductivity effect. The important parameters, such as relaxation wavelength, static component of the dielectric constant, and ionic conductivity, were determined at various conditions using the nonlinear least squares method. Penetration depth was estimated under various conditions. The dielectric constant decreased with increasing frequency, concentration, and temperature for both liquid foods. At low frequencies, the loss factor decreased with increasing frequency, but at high frequencies, it increased with frequency. The effect of ionic loss was substantial at higher temperatures and lower frequencies for each material. Dielectric properties of rice vinegar and sake could be adequately analyzed with the modified Cole-Cole relation including ionic conductivity effect.