|ROELVINK, JOCHEM - Former ARS Employee|
Submitted to: Journal of Microwave Power and Electromagnetic Energy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/8/2014
Publication Date: 12/1/2014
Citation: Trabelsi, S., Roelvink, J. 2014. Investigating the influence of aging on radiofreuqncy dielectric properties of chicken meat. Journal of Microwave Power and Electromagnetic Energy. 48(4):215-220.
Interpretive Summary: Quality of chicken meat is of interest to both producers and consumers. Quality is often assessed through measurement of physical properties including color, pH, water holding capacity, drip loss, cook yield and texture. The procedures for determining these quality factors are lengthy and tedious and often require costly instrumentation. Chicken meat is composed on average of 70% water, 20% proteins, and 5% lipids. Dielectric properties of materials are the electrical characteristic that determines their interaction with electric fields. If good correlations between quality factors and the dielectric properties of chicken meat can be found, the quality of the meat could be sensed rapidly with suitable instruments that sense the dielectric properties. Because water is the major component in chicken meat, and water has higher dielectric properties than the other components, dielectric spectroscopy, the measurement of dielectric properties over a range of frequencies could be useful for rapid assessment of chicken meat quality. A major concern in chicken meat consumption is the deterioration of quality during storage. Effects of aging on chicken meat dielectric properties were investigated through measurement of these properties with an open-ended coaxial-line probe between 200 MHz and 20 GHz at room temperature. Results of the measurements show that the dielectric constant decreases with the storage duration at all frequencies, while the dielectric loss factor increased with storage duration at frequencies below 4 GHz and decreased slightly or remained constant at frequencies above that. The same trends for the dielectric constant and dielectric loss factor were observed in their variation with water loss. To further understand the dynamics of aging, the effect of water loss by mechanical means on the dielectric properties of fresh chicken meat were investigated. Both the dielectric constant and dielectric loss factor decreased with water loss. Further studies are needed to assess the usefulness of dielectric properties in sensing quality of chicken meat. Successful sensing of quality by rapid measurements would be of benefit to processors, marketers and consumers.
Technical Abstract: Changes in quality attributes of aging chicken meat were tracked through measurement of the dielectric properties with an open-ended coaxial probe between 200 MHz and 20 GHz at 23 °C. The chicken meat was stored in a refrigerator for 8 days at 4 °C. Changes in dielectric constant and loss factor were measured daily over an 8-day span study. The dielectric constant decreased with frequency and storage duration with a slope change at about 4 GHz. The frequency dependence of the dielectric loss factor was dominated by the ionic conduction in the lower frequency range and dipolar relaxation of water above 3 GHz. The dielectric loss factor increased with storage duration for frequencies below 3 GHz and remained almost constant above that frequency. A Cole-Cole model revealed that the ionic conductivity, s, and relaxation time spread, a, increased with storage time, while the relaxation time, t, remained almost constant.