Eggs – Does beating hot oil into eggs before cooking an omelette make a difference

The main purpose of beating an egg is to "denature" the protein within the egg. Proteins are long chains of amino acids and they have lots of internal chemical bonds, which hold them together into tightly contained units. When a protein is denatured, those internal bonds break and the amino acid chains unravel and become elongated. At the same time, atoms that were previously bonded (as part of the internal bonds I mentioned) become available to bond with other molecules.

When an egg is heated to 40 degrees celsius, its protein chains become denatured and elongate, which allows chemical reactions to occur. The egg changes from a liquid solution of protein into a solid mass.

A similar thing happens with you beat an egg. The physical act of beating causes the protein strands to stretch, thereby causing the protein to denature (the internal bonds are broken as a result of the application of physical force). So, rather than the protein chains being bound up into tight balls, they become long strands. This is similar to gluten when it is developed. These strands form structures that allow the trapping of air, which results in a lighter texture.

Beating eggs is not just about mixing. It's about changing the structure of the eggs to produce a physical effect. To read more about this, see "The Science of Cooking" by Peter Barham.

I have a theory about your omelette (and sadly, no means to test it). But I think it is plausible, please feel free to point out logical errors.

I think that the unappetizing coloring is due to the creation of sulfur salts in your pan. Egg whites are rich in sulfur, as are all alliums (including chives). If you heat them enough (you don't mention whether you overcooked the omelette, but it happens often enough), the heat changes the molecules in which the sulfur is bound, and the sulfur atoms (or sulfur containing ions) are free to react with whatever they find around. If they happen to find iron or copper, they form sulfides and sulfates with them. These sulfides and sulfates have colors ranging from blue to green, and pure iron sulfide is black. A mixture of them with the yellow yolk can easily look gray, especially when the color is desaturated through the addition of white cream cheese.

You say you used a coated pan, but there are still possible sources for the iron and copper. First, nuts contain trace elements, including iron and copper. Second, yolks too contain iron (in fact, the bluish coloring on the surface of a hard boiled yolk is an iron sulfide created when the proteins in the egg white denaturated from the heat). Third, you can't exclude contamination of the ingredients (plants sometimes store metal ions from the environment).

I have no way to prove any of the above, but at least it sounds like a good working theory. But I will understand if you aren't eager to reproduce in order to investigate the effect closer.