How to boil eggs to harden the shell

Boiling eggs is quite common and simple in our daily life. If you want to prevent the boiled eggs from breaking easily, you can add a small amount of salt or baking soda. Adding these ingredients will harden the eggshells, which can also prevent the eggshells from cracking when boiling eggs. Salt and baking soda can increase the hardness of the eggshells.

How long does it take to boil eggs?

It is best to boil eggs in cold water and cook for 3 minutes after the water boils. At this time, the eggs are soft and have the highest nutritional value and are most conducive to human absorption. Wash the eggs, put them in cold water, and after boiling, time them for 3 and 5 minutes respectively, then remove them from the water and cool them down. "3-minute eggs", the egg white is cooked and tender, and the egg yolk is just cooked and slightly runny. "5-minute eggs", the egg white is cooked and tender, and the egg yolk is cooked but not hard. Eggs boiled at different times will take different amounts of time to digest in the human body. "3-minute eggs" are slightly cooked and easiest to digest, taking about 1 hour and 30 minutes; "5-minute" eggs are half-cooked and take about 2 hours to digest in the human body; eggs that are boiled for too long take a relatively longer time to digest in the human body. The most nutritious eggs are the "5-minute eggs". These eggs are not only soft and tender, with a strong egg flavor, but are also beneficial to human nutrition.

If eggs are cooked in boiling water for more than 10 minutes, a series of chemical changes will occur inside them. The protein structure becomes tighter and less likely to come into contact with the protein-digesting enzymes in gastric juice, making it more difficult to digest. The protein in eggs contains a lot of methionine. After being heated for a long time, it will decompose into sulfide, which reacts with the iron in the egg yolk to form iron sulfide which is difficult for the human body to absorb, resulting in a lot of nutritional loss.

Undercooked eggs are more harmful. Raw eggs are not only contaminated with Salmonella, but also contain two harmful substances: anti-enzyme protein and anti-biotin protein. The former will affect the digestion and absorption of protein; the latter can combine with biotin in food, leading to biotin deficiency in the human body and causing symptoms such as mental fatigue and muscle aches. The above two substances will be destroyed once the eggs are cooked.

How to cook boiled eggs

Boiling eggs may seem simple, but it actually requires a lot of knowledge. If the eggs are not cooked properly, the nutritional value will be destroyed.

Wash the fresh eggs and soak them in a pot of water.

minutes, then bring to a boil over low heat. This is to prevent the eggshells from bursting during cooking.

Bring the eggs to a boil over low heat, then simmer over medium heat for 8 minutes. Avoid cooking for too long, otherwise the ferrous ions in the egg yolk will react chemically with the sulfur ions to form a brown precipitate of ferrous sulfide, which will hinder the body's absorption of iron.

You don't have to take out the cooked eggs immediately. Wait 1-2 minutes before taking them out, or put them in boiled water or cold water to cool down for half a minute. This will make it easier to peel the eggs. To prevent bacterial infection, it should not be placed in tap water.