Temperature and moisture dependent dielectric properties of egg white powder

Dielectric properties of egg white powder (EWP) in the moisture content range of 5.5-13.4% d.b. were measured with an impedance analyzer employing a coaxial probe technique in the frequency range from 10 to 3000 MHz and temperature range from 20 degrees C to 100 degrees C. The dielectric properties of EWP were maximum in the frequency range of 250-300 MHz for temperatures ranging from 30 degrees C to 100 degrees C at all moisture content levels. The dielectric constant and loss factor values of EWP increased with an increase in moisture content and temperature. The second-order models were fitted for experimental dielectric constant and loss factor data as a function of moisture content and temperature at five selected radio (13.56, 27.12 and 40.68 MHz) and microwave (915 and 2450 MHz) frequencies with coefficients of determination >= 0.939. Penetration depths of EWP were calculated for five selected frequencies at different moisture contents and temperatures. (C) 2015 Elsevier Ltd. All rights reserved.