Direct Measurement of Thermal Effusivity of Avian Eggs and Their Constituents: A Photopyroelectric Study
Gábor Szafner1, Dane Bicanic2,3, Katalin Kovácsné Gaál4 and Ottó Dóka1*
1Institute of Mathematics, Physics and Informatics, Faculty of Agricultural and Food Sciences, University of West Hungary, Deák F. sq. 1, HU-9200 Mosonmagyaróvár, Hungary
2Laboratory of Biophysics, Department of Agrotechnology and Food Sciences, Wageningen University and Research Centre, Dreijenlaan 3, NL-6703 HA Wageningen, The Netherlands
3Department of Food Quality and Nutrition, Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia
4Institute of Animal Breeding, Faculty of Agricultural and Food Sciences, University of West Hungary, Vár 4, HU-9200 Mosonmagyaróvár, Hungary
Article history:
Received: November 6, 2011
Accepted: February 12, 2012
Key words:
thermal properties of avian eggs, thermal effusivity, heat penetration coefficient, photopyroelectric method
Summary:
The front configuration photopyroelectric method has been used to determine, in a nondestructive fashion, thermal effusivity of the yolk and the white of eggs of several bird species as well as of the blends of a single egg yolk and egg white (also called liquid eggs) of different avian eggs. Statistically significant differences in thermal effusivity of egg whites were observed in ten out of twenty-one comparisons made. However, in the case of egg yolks, the differences were observed in twenty among twenty-one comparisons carried out. These observations are related to a varying fat content of egg yolk and a large amount of water found in egg white. The effusivity of the blends prepared from yolks and eggs varies because the contents of the yolk and white in avian eggs differ.
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