Influence of color on dielectric properties of marinated poultry breast meat

Authors: Samuel, Dora; Trabelsi, Samir

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/9/2012
Publication Date: 8/15/2012
Citation: Samuel, D.D., Trabelsi, S. 2012. Influence of color on dielectric properties of marinated poultry breast meat. Poultry Science. 91:2011-2016.

Interpretive Summary: The absorption of microwave energy in food is influenced by the dielectric properties of the material. Moisture or water content is the dominant factor affecting the dielectric properties of foods and their interaction with radio-frequency (RF) and microwave (MW) electric fields. Up to 50% of raw poultry meat in the United States is marinated with mixtures of water, salts, and phosphates which are used to increase water-holding capacity and cooked yield. Salt and phosphates can contribute to non-uniform temperature distribution and thus greatly affect the heating rate of foods during microwave heating. It has been reported that pH variation associated with extreme raw breast meat color variation can affect breast meat marination and cooked meat quality. The influence of color on the dielectric properties was observed prior to marination. However, minimal color influence was detected after marination of the poultry breast meat.

Technical Abstract: The dielectric behavior of foods when exposed to radio-frequency and microwave electric fields is highly influenced by moisture content and the degree of water binding with constituents of the food materials. The ability to correlate specific food quality characteristics with the dielectric properties can lead to the development of rapid, nondestructive techniques for such quality measurements. Water-holding capacity (WHC) and water-binding capacity are critical attributes in meat quality. Up to 50% of raw poultry meat in the United States is marinated with mixtures of water, salts, and phosphates. The objective of this study was to determine if variations in breast meat color would affect the dielectric properties of marinated poultry meat over a broad frequency range from 500 MHz to 50 GHz. Poultry meat was obtained from a local commercial plant in Georgia (USA). Color and pH measurements were taken of the breast filets. Groups of breast filets were sorted into classes of pale and normal before adding marination pickup percentages of 0, 5, 10, and 15. Breast filets were vacuum tumbled and weighed for pickup percentages. Dielectric properties of the filets were measured with a coaxial open-ended probe on samples equilibrated to 25º C. Samples were then ground for measurement of the ionic conductivity of each sample. Samples from pale meat exhibited higher dielectric properties than samples from normal meat. No differences could be observed between samples from pale and normal meat after marination of the samples. Overall, dielectric properties increased as the marination pickup and ionic conductivity increased. Marination pickup strongly influenced the dielectric loss factor. Differences between samples marinated at different pickup levels were more pronounced at lower frequencies for the dielectric loss factor. As frequency increased the differences between samples decreased. Differences in dielectric constant between samples were not as consistent as those seen with the dielectric loss factor.