title: Challenges in Radiofrequency Pasteurization of Shell Eggs: Coagulation Rings.
abstract: A total of 50 different configurations of simple radiofrequency (RF) heating at 27.12 MHz of a shell egg were simulated using a finite element model with the purpose of pasteurizing the egg. Temperature-dependent thermal and dielectric properties of the yolk, albumen, and shell were measured, fitted, and introduced into the model. A regression equation that relates the top electrode voltage to the gap between the electrodes and vertical position of the egg was developed. Simulation and experimental results had good agreement in terms of temperature deviation (root mean squared error ranged from 0.35 °C to 0.48 °C) and both results demonstrated the development of a "coagulation ring" around the air cell. The focused heating near the air cell of the egg prevented pasteurization of the egg due to its impact on quality (coagulation). Analysis of the electric field patterns offered a perspective on how nonuniform RF heating could occur in heterogeneous food products. The results can be used to guide development of RF heating for heterogeneous food products and further development of RF pasteurization of eggs.
authors.affiliation: Dept. of Food Science and Technology, Univ. of Nebraska-Lincoln, Lincoln, NE, 68588, U.S.A.
authors.forename: Soon Kiat
authors.initials: SK
authors.lastname: Lau
authors.affiliation: Dept. of Poultry Science, Univ. of Georgia, Athens, GA, 30602-2772, U.S.A.
authors.forename: Harshavardhan
authors.initials: H
authors.lastname: Thippareddi
authors.affiliation: Dept. of Biological Systems Engineering, Univ. of Nebraska-Lincoln, Lincoln, NE, 68583-0726, U.S.A.
authors.forename: David
authors.initials: D
authors.lastname: Jones
authors.affiliation: Dept. of Mechanical and Materials Engineering, Univ. of Nebraska-Lincoln, Lincoln, NE, 68588-0526, U.S.A.
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Negahban
authors.affiliation: Dept. of Food Science and Technology, Univ. of Nebraska-Lincoln, Lincoln, NE, 68588, U.S.A. jeyam.subbiah@unl.edu.|Dept. of Biological Systems Engineering, Univ. of Nebraska-Lincoln, Lincoln, NE, 68583-0726, U.S.A. jeyam.subbiah@unl.edu.
authors.forename: Jeyamkondan
authors.initials: J
authors.lastname: Subbiah
mesh_terms: D000818:Animals; D002138:Calibration; D002645:Chickens; D003198:Computer Simulation; D004528:Egg Shell; D004531:Eggs / Q000032:analysis*; D004566:Electrodes; D020342:Finite Element Analysis; D005504:Food Analysis / Q000379:methods*; D006358:Hot Temperature; D008962:Models, Theoretical; D061352:Pasteurization / Q000379:methods*; D011846:Radio Waves; D012044:Regression Analysis
keywords: dielectric properties; egg; heat transfer; radiofrequency heating; simulation