Jianping Wu, Andreas Schieber and graduate students Chamila Nimalaratne and Daise Lopes-Lutz of the University of Alberta examined egg yolks produced by hens fed diets of mostly wheat or corn, and found the yolks contained tryptophan and tyrosine, two amino acids high in antioxidant properties. The antioxidants help in the prevention of cardiovascular disease and cancer.
The discovery, while important, may be only the beginning of finding antioxidant properties in egg yolks, Wu says.
"Ultimately, we're trying to map antioxidants in egg yolks so we have to look at all of the properties in the yolks that could contain antioxidants, as well as how the eggs are ingested," Wu says in a statement.
In previous research, Wu's team discovered egg proteins were converted by enzymes in the stomach and small intestines and produced peptides that act the same way as ACE inhibitors -- prescriptions drugs that are used to lower high blood pressure.
The findings were published in the journal Food Chemistry.