One of the easiest foods to cook is definitely hard boiled eggs: hard to miss, just boil the water and put them in. After peeling our dish, you may see a grey or green ring “discoloured” between the egg white and the yolk: have you ever wondered what it is and why it is created?
The grey colouration appears “simply” due to a chemical reaction during the boiling of the egg (and yes, it is safe and the egg can be eaten quietly). The proteins in the egg are kept together by sulfur, which decomposes with heat and becomes hydrogen sulphide. The latter combines with the iron in the egg yolk and can produce the result we see often.
It is iron sulphide that creates grey (or green) rings around the egg, and this is usually the result of excessive cooking. Nothing serious then, it is just a sign that you have too cooked your egg. From a nutritional point of view only one part (very small and insignificant!) of iron was lost.
In short, color is not a symptom of “unpleasantness” of eggs. By the way: what is the difference between white and brown eggs? While according to a bio-engineering point of view, the egg is an amazing biological object that has a series of characteristics that make it a structure \”perfect” (as we told you in a previous news).