There are many ways to eat eggs, such as boiled eggs, fried eggs, scrambled eggs, egg soup...... However, if you want to say that it is simple and convenient, it must be boiled eggs! For office workers who are short of time, boiled eggs are the best in the world to supplement protein!
Although the job of boiling eggs is simple, the eggs obtained by boiling time are also very different, how long does it take to boil to get the egg you want?
After experiments, we found that when the eggs are boiled in a pot under water at room temperature, when they are boiled for 8~9 minutes, the eggs are the most delicious.
Next, let's talk about the taste of eggs and the changes in their nutrition during this experiment~
In order to boil the best eggs
We did an experiment
In order to minimize the error, before boiling the eggs in this experiment, first of all, ensure that the surface of the eggs is clean and clean, and there is no chicken feces, and secondly, the eggs should be taken out of the refrigerator in advance to control the temperature of the eggs at room temperature.
Take a deeper pot with enough water to submerge the eggs, bring the water to a boil before adding the eggs, and prepare 1 basin of cold water.
A total of 13 eggs, boil them over medium heat for 3min~20min, take out the eggs that have been boiled for a long time and put them in cold water to cool down for 3~5min, so that they can be easily peeled. After all the shells are boiled and peeled, cut them in half and compare them in a good position.
Source: Author
As you can see from the diagram above:
- Cook for 3min: When peeling the shell, it obviously feels soft, although the egg white is solidified, the texture is soft, and the egg will be pinched and popped with a little force. The yolk is not solidified at all and is in a liquid state.
- Boiled for 4min: The egg whites are solidified and the hardness is slightly improved compared to eggs boiled for 3min, but the yolk is still in a flowable state.
- Cook for 5min: the egg whites are coagulated, the hardness is further improved, but it is still relatively soft, and the egg yolk is in a semi-flowing state.
- Cook for 6min: the egg whites are coagulated, and most of the egg yolks are coagulated, but the middle part is semi-coagulated and liquid, and the fishy smell is strong.
- Cook for 7min: the egg whites are coagulated, although the egg yolk is almost all solid, a little bit in the center is still semi-solid, the color is brighter, and the taste is slightly fishy.
- Cook for 8~9min: egg whites are inherently elastic, the egg yolk is all solidified but still relatively soft, the color is bright, and the taste is soft.
- Cook for 10min: The egg whites and egg yolks are basically cooked, and most of the egg yolks have changed from bright orange to yellow, and the firmness has increased.
- Cook for 12~15min: The egg whites and egg yolks are fully cooked, the egg whites feel harder, the egg yolks have become firmer, the color has become yellow, the yolk fat has a strong fragrance, and the taste is slightly dry, a little choking.
Source: Author
Secondly, when the egg is boiled for more than 15min, the yolk turns green:
- Boiling for 20min: During the boiling process, the outer surface of the egg yolk did not turn green for 10min and 12min, the outer surface of the yolk of the egg boiled for 15min only slightly turned green, and the outer surface of the yolk of the egg boiled for 20min began to turn green significantly.
Among these eggs, the eggs at room temperature are boiled in a pot under boiling water for 8~9 minutes to taste the best, the eggs at this time are not fishy, the elasticity is moderate, and the taste is soft and not choking. If you like soft-boiled eggs, boiling them for 4~5 minutes gives the best results.
Nutritional changes in boiled eggs
In the matter of eating eggs, some people think that hard-boiled eggs are nutritious and delicious, but some people think that the nutrition of hard-boiled eggs is destroyed, and raw eggs are nutritious. In fact, the process of boiling eggs does not have much effect on the main nutrients.
protein
The most important purpose of eating eggs is to supplement protein, the protein content of eggs is 13.1g/100g, and it is a complete protein, the amino acid composition is very similar to the human body, and the human body absorbs and utilizes it very high. The protein in raw eggs is gelatinous, which is not easy for the human body to digest and absorb, while the protein will be denatured after cooking cooked eggs, which is easier for the body to absorb and utilize. Studies have long found that cooked eggs have a protein digestibility of up to 97%, while raw eggs are only 50% at most.
This is because raw eggs contain antitrypsin substances, which inhibit trypsin activity and affect protein digestion.
Vitamin A, vitamin E
They are fat-soluble vitamins with antioxidant properties and are relatively stable in general cooking, and vitamin A and vitamin E do not change much after raw eggs become mature eggs.
B vitamins
Eggs contain nutrients like vitamin B1, vitamin B2, niacin, biotin, vitamin B12, etc., and their loss in boiled eggs is minimal and there is no need to get tangled.
Raw eggs contain avidin, which will affect the body's absorption of biotin, biotin participates in the digestion process of food, if it is missing, it may lead to perioral dermatitis, conjunctivitis, hair removal, hair thinning, light hair color, fatigue and other symptoms, severe deficiency of people can lose eyebrows, hair, eyelashes in 3~6 months. However, the average person is rarely deficient in biotin, and most people who eat raw eggs for a long time may develop biotin deficiency.
Minerals
Eggs are rich in minerals, such as calcium, phosphorus, potassium, and iron, which are relatively stable in cooking and have little effect.
Phospholipids, cholesterol
Boiled eggs have little effect on phospholipid and cholesterol levels, but prolonged cooking may occur with varying degrees of oxidation, which is not good for health.
Although cooked eggs are better absorbed, they should not be boiled for too long, otherwise the surface of the egg yolk will gradually turn green. This is because during the cooking process of eggs, the iron in the yolk and the sulfur in the egg white are combined to form dark green ferrous sulfide, so the surface of the yolk becomes dark green.
This ingredient is not harmful to the human body, but it will affect appetite, although it will also affect the absorption of iron in egg yolks, but after all, the iron content of 1 egg is not much and the utilization rate is low, so it doesn't matter.
Tea eggs that have been boiled for a long time at the breakfast shop. Source: Author
I love soft-boiled eggs, and this cannot be ignored
Soft-boiled eggs mostly refer to eggs whose egg whites have solidified and the yolk is in semi-flowing or semi-solid conditions, and they are very popular because of their smooth and delicious taste.
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From a nutritional point of view, antitrypsin and avidin are mainly found in egg whites, as long as the egg whites are coagulated, the anti-nutrients are almost eliminated, and the egg yolk is not overheated, so that the egg yolk is well retained in nutrients, and the cholesterol is almost oxidized, which is also a relatively healthy food.
However, people who love soft-boiled eggs really have to be vigilant, and they may get food poisoning. Improper cooking of eggs can carry salmonella and other bacteria, increasing the risk of food poisoning.
Salmonella is a bacterium found in the intestines of humans and animals, and is commonly found in foods of animal origin, including eggs, meat, and raw milk. Salmonella can infect eggs in two ways: first, it can be infected by the reproductive tissues of the infected hen before the eggshell is formed, and second, it can contaminate the egg through the feces on the eggshell, which is not actually completely "sealed", the surface is covered with small holes, and bacteria can easily penetrate the inside of the egg through the shell.
Don't underestimate Salmonella, after being infected by it, it can cause abdominal pain, diarrhea and vomiting, and severe death. However, it is not heat-tolerant, dying instantly when heated to 100°C, and destroying it after 15 minutes at 60°C.
In general, when the yolk temperature reaches 60°C, it becomes opaque, and when it reaches 74°C, it gradually forms a solid. So, if the egg white of the soft-boiled egg you eat has solidified and the texture is soft, and the yolk is still in a liquid flowable state, the core temperature of the yolk may not have reached more than 60°C, and it is difficult to kill Salmonella.
Therefore, for the sake of food safety, it is recommended that eggs should not be eaten raw, and it is better to eat them cooked as much as possible. Friends who really love soft-boiled eggs must pay attention to the following 2 points:
Pay attention to how you save it
Raw eggs generally need to be stored at 0~10°C, and it is best to seal them separately and store them in the refrigerator.
Be optimistic about the expiration date
This is because eggs are not airtight despite their shells, and their surfaces are covered with small holes, which cannot guarantee complete sterility, and bacteria can grow over a long period of time or in the wrong way.
summary
The taste of soft-boiled eggs is unique and delicious, but if you are careless, it will increase the potential food safety hazards, and the little friends who are "worried" simply eat hard-boiled eggs! Raw eggs at room temperature and other water are boiled in the pot, and the state and taste of boiling for 8~9 minutes are better, everyone has different tastes, and you can choose the boiled egg time according to your preferences.
If it is an egg that has just been taken out of the refrigerator, it is recommended to put the water in a pot under cold water, start timed for 3 minutes after the water boils, then turn off the heat and leave the lid uncovered, and simmer for 5 minutes.
bibliography
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Planning and production
This article is a work of popular science China-Star Project
Produced by the Department of Science and Technology of the China Association for Science and Technology
Producer: China Science and Technology Press Co., Ltd., Beijing Zhongke Galaxy Culture Media Co., Ltd
Author丨Xue Qingxin is a registered dietitian
Audit丨Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center
Planning丨 A Nuo Linlin