Eggs with shells are boiled in cold water, and boiled for five minutes. At this time, the boiled eggs can completely preserve nutrition and kill harmful bacteria. The air pressure is different in different areas, and the boiling time is inconsistent.

Many people think that the longer the eggs are cooked, the better, so as to ensure that the eggs are cooked. This idea is also incorrect. When eggs are boiled in boiling water for more than ten minutes, chemical changes will take place inside. At this time, its protein structure becomes more compact, and it is not easy to contact with digestive enzymes in the stomach, so it is difficult to digest. Moreover, methionine in eggs will decompose into sulfide after long-term heating, which will react with iron in egg yolk to generate iron sulfide that is not easily absorbed by human body, and the loss of nutrition will be more serious.

Extended data:

Boiled eggs are one of the most common ways to eat eggs. You can cook them in water. However, although boiled eggs are rich in nutrition, eating too much will lead to indigestion, so boiled eggs should not be eaten too much, generally not more than 1 a day. If boiled eggs are cooked properly, the nutritional absorption rate of boiled eggs can reach 100%, thus becoming the first choice for breakfast or nutritious meals.