Use of Dielectric Properties to Detect Egg Protein Denaturation

Abstract

Changes in water and ion binding that occur during egg protein denaturation can be detected by measuring the dielectric properties. The dielectric properties of egg yolk, egg white and egg ovalbumin were tested from 25 to 105 degrees C at 11 frequencies from 300-2450 MHz. DSC was used to determine the temperature of protein denaturation. Both the dielectric constant and loss factor of egg yolk decreased due to denaturation of the protein lipovitellin. The dielectric constant increased at the initial denaturation and decreased after the complete denaturation and aggregation of egg ovalbumin in both egg white and ovalbumin.

Effect of Radiofrequency Heating on the Dielectric and Physical Properties of Eggs

“…The time delay between the electric field and dipole polarization suggests a permanent degradation of free energy. In accordance with the Debye model this frequency is dependent on the viscosity of the liquids, such that more viscous liquids relax at lower frequencies as compared to the less viscous ones [2]. In eggs, the suspended matter is biomolecules and electrolytes and has much lesser relaxation frequencies than water.…”

Dielectric properties of egg whites and whole eggs as influenced by thermal treatments

“…The dielectric properties of egg whites are primarily dependent on water, electrolytes, and proteins such as ovalbumin and conalbumin (Bircan & Barringer, 2002;Ragni, Al-Shami, Mikhaylenko, & Tang, 2007). Previous research reports that the protein denaturation temperature of liquid egg whites is in the range of 58-62 C, ovalbumin at around 84 C, and conalbumin in the range of 65-70 C (Bircan & Barringer, 2002;Donovan, Mapes, Davis, & Garibaldi, 1975;Payawal, Lowe, & Stewart, 1946).…”

“…Many studies determine the dielectric properties of food materials in RF and microwave frequency ranges, including vegetables, fruits, meat, pasta, and others (Bircan & Barringer, 2002;Guan, Cheng, Wang, & Tang, 2004;Nelson, 1992;Sipahioglu & Barringer, 2003;Tinga & Nelson, 1973;Tong & Lentz, 1993;Tran & Stuchly, 1987;Wang, Wig, Tang, & Hallberg, 2003). However, there is a lack of systematic studies on the dielectric properties of whole eggs and egg whites at RF from 27 to 1800 MHz over temperatures from 20 to 120 C. Knowledge of dielectric properties is important to the research of RF and microwave heating in applications for pasteurization and sterilization of egg products.…”

Dielectric properties of honey adulterated with sucrose syrup

“…Ash content increased with increasing sucrose content in mixture. The dielectric constant is decreased by Frequency, Hz the presence of ions, which bind water and reduce its mobility (Bircan and Barringer, 2002) . Similar results were also found in honey-sucrose syrup mixture of yellow-locust and milk-vetch.…”