Measuring changes in radio-frequency dielectric properties of chicken meat during storage

Abstract

Changes in dielectric properties of stored chicken meat were tracked by using a radio-frequency dielectric spectroscopy method. For this purpose, the dielectric properties were measured with an open-ended coaxial-line probe and a vector network analyzer over a broad frequency range from 200 MHz to 20 GHz at 23 °C. Chicken meat samples were stored in a refrigerator for 8 days at 4 °C. Dielectric constant and loss factor were measured daily over that period. The dielectric constant decreased with frequency and storage duration with a slope change at about 4 GHz. The dielectric loss factor increased with storage duration for frequencies below 3 GHz and remained almost constant above that. The frequency dependence of the dielectric loss factor was dominated by ionic conduction in the lower frequency range and dipolar relaxation of water above 3 GHz. For frequencies below 3 GHz, both the dielectric loss factor and loss tangent increased linearly with storage duration. A three-dimensional representation of the dielectric loss factor as a function of storage duration and conductivity provided analytical expressions that can be used to track chicken meat aging from measurement of the dielectric properties at a single frequency.