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A differential scanning calorimetric study of conversion of ovalbumin to S ‐ovalbumin in eggs
Author(s) -
Donovan John W.,
Mapes Carol J.
Publication year - 1976
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740270220
Subject(s) - ovalbumin , differential scanning calorimetry , egg white , chemistry , kinetics , egg allergy , denaturation (fissile materials) , chromatography , biochemistry , thermodynamics , biology , nuclear chemistry , immunology , allergy , antigen , physics , quantum mechanics , food allergy
The presence of S ‐ovalbumin, a more heat‐stable form of ovalbumin formed on storage of eggs, can be determined by differential scaning calorimetry of egg white. At a heating rate of 10°C/min, at pH 9, the characteristic denaturation temperature of ovalbumin is 84.5°C, that of S , ovalbumin, 92.5°C. The formation of S ‐ovalbumin proceeds through a previously unrecognised intermediate species having a denaturation temperature of 88.5°C. The kinetics of the conversion on storage of eggs at 4, 22 and 37°C have been determined. Differential scanning calorimetry is a rapid and convenient method of determining the quality of eggs held in storage. Freeze‐dried preparations of ovalbumin stored in the cold for 20 years showed partial conversion to the intermediate, but not to S ‐ovalbumin.