Boiling eggs seems simple, but it is difficult to control the heat. If the time is too short, the egg yolk will be undercooked, and if the time is too long, the eggs will become old and unpalatable.
In fact, the best time to boil eggs is easy to grasp. Put cold water in the pot and wait for 5 minutes after the water boils. The cooked eggs will not only kill harmful pathogenic bacteria, but also preserve nutrients relatively completely.
If an egg is cooked in boiling water for more than 10 minutes, a series of chemical changes will occur inside it. The protein structure becomes more compact and is less likely to come into contact with the protein-digesting enzymes in the 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 yolk to form iron sulfide that is difficult for the human body to absorb, resulting in greater nutritional losses.
Undercooked eggs are more harmful. Raw eggs not only have the problem of salmonella contamination, but also have two harmful substances, anti-enzyme protein and avidin. The former will affect the digestion and absorption of protein; the latter can combine with biotin in food, causing biotin deficiency in the human body and causing symptoms such as mental fatigue and muscle soreness. Once the eggs are cooked, the above two substances will be destroyed.
In addition, when boiling eggs, you can also master the following skills to prevent the loss of nutrients: the water must cover the eggs, otherwise the protein will not easily solidify in places that are not immersed in water, which will affect digestion; soak the eggs in cold water for a while before boiling to reduce the egg content. Internal air pressure; then use medium heat and boil cold water to prevent the eggshell from cracking and avoiding the loss of nutrients.