2024 Volume 38 Issue 2 Pages 169-177
Objective: The aim in this study was to analyze the solubility and immunoglobin E (IgE) -binding ability of the egg white proteins in boiled eggs during boiling.
Methods: Boiled eggs were prepared by cooking large commercial hen's eggs in boiling water. Protein extraction from the raw (boiled for 0 min) and boiled egg whites, after lyophilization, was performed with phosphate-buffered saline (PBS), sodium dodecyl sulfate and urea solution, and 2-mercaptoethanol (2-ME) solution; the extracts were analyzed using the inhibition ELISA, SDS-PAGE, and IgE immunoblotting.
Results: The amount of ovalbumin (OVA) in the PBS fraction decreased significantly over time during 7 and 9 minutes of boiling. The SDS-PAGE results showed that the ovotransferrin, OVA, and lysozyme disappeared over time in the PBS fraction but were detected in the 2-ME solution fraction. Additionally, the band presumed to be ovomucoid (OVM) did not disappear from the PBS fraction after 20 minutes of boiling. The bands of IgE-binding proteins in the PBS fraction decreased at approximately 5 and 10 minutes.
Conclusions: Egg white proteins except OVM gradually became insoluble in water up to 10 minutes of boiling time and did not change thereafter. The results of this study provide basic data on the guidance of heated egg consumption.
