How many minutes should you boil eggs to make them tasty? This experiment will tell you!

You have all eaten eggs, right? There are so many ways to eat them, such as boiled eggs, fried eggs, scrambled eggs, egg soup... However, if you want to talk about the simplest and most convenient way, it must be boiled eggs! For office workers who are short on time, boiled eggs are the best way to supplement protein!

Although boiling eggs is a simple task, the resulting eggs will vary greatly if the boiling time is different. How long should you boil them to get the egg you want?

After experiments, we found that eggs at room temperature are most delicious when they are cooked in boiling water for 8 to 9 minutes.

Next, let’s talk about the changes in the taste and nutrition of eggs during this experiment~

To cook the best eggs

We did an experiment

In order to minimize errors, before boiling the eggs in this experiment, we must first ensure that the surface of the eggs is clean and free of chicken feces. Secondly , the eggs must be taken out of the refrigerator in advance and the temperature of the eggs must be controlled at room temperature.

Take a deeper pot with enough water to cover the eggs. Bring the water to a boil and then put the eggs in. Also prepare a basin of cold water.

There are 13 eggs in total. Cook them over medium heat for 3-20 minutes. Take out the eggs that have reached the cooking time and put them in cold water to cool down for 3-5 minutes so that they can be easily peeled. After all the eggs are cooked and peeled, cut them in half and place them in a position for comparison.

Image source: Author

As can be seen from the above figure:

- Cook for 3 minutes : When peeling the shell, it feels soft. Although the egg white is solidified, it is soft in texture and will burst if you squeeze it with a little force. The egg yolk is not solidified at all and is liquid.

-Boil for 4 minutes : The egg white is coagulated and its hardness is slightly higher than that of eggs boiled for 3 minutes, but the yolk is still in a flowable state.

-Boil for 5 minutes : The egg white solidifies and the hardness increases further, but it is still relatively soft, and the egg yolk is in a semi-fluid state.

-Boil for 6 minutes : The egg white is solidified, and most of the egg yolk is solidified, but the middle part is semi-solidified liquid with a strong fishy smell.

-Boil for 7 minutes : The egg white is solidified. Although the egg yolk is almost completely solidified, there is still a bit of semi-solid in the center. The color is brighter and the taste is slightly fishy.

- Cook for 8~9 minutes : The egg white is solidified and elastic, the egg yolk is completely solidified but still relatively soft, with bright color and soft texture.

-Boil for 10 minutes : The egg white and yolk are basically cooked. Most of the egg yolk has changed from bright orange to yellow and has become harder.

-Cook for 12~15min : The egg white and yolk are fully cooked. The egg white feels harder and the egg yolk becomes firmer and turns yellow. The yolk has a stronger fat aroma and tastes slightly dry and a bit choking.

Image source: Author

Secondly, when the egg is boiled for more than 15 minutes, the yolk will turn green:

-Boil for 20 minutes : During the cooking process, the outer surface of the yolk did not turn green at 10 and 12 minutes. The outer surface of the yolk of the egg boiled for 15 minutes only turned slightly green, while the outer surface of the yolk of the egg boiled for 20 minutes began to turn obviously green.

Among these eggs, eggs at room temperature taste best when boiled in boiling water for 8 to 9 minutes. At this time, the eggs are not fishy, ​​have moderate elasticity, and are soft and non-choking . If you like to eat soft-boiled eggs, boil them for 4 to 5 minutes for the best effect.

Nutritional changes of boiled eggs

When it comes to eating eggs, some people think that hard-boiled eggs are nutritious and delicious, but others think that the nutrients in hard-boiled eggs are destroyed and that only raw eggs are nutritious. In fact, the cooking process of eggs does not affect the main nutrients much.

1

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 that of the human body, and the human body has a very high absorption rate. The protein in raw eggs is gelatinous and difficult for the human body to digest and absorb. However, when the eggs are cooked, the protein will denature and be more easily absorbed and utilized by the human body. Studies have long found that the protein digestibility of cooked eggs is as high as 97%, while that of raw eggs is only 50% at most.

This is because raw eggs contain anti-trypsin substances, which will inhibit the activity of trypsin and affect the digestion of protein.

2

Vitamin A, Vitamin E

Both are fat-soluble vitamins with antioxidant properties. They are relatively stable during normal cooking. After raw eggs become cooked eggs, the contents of vitamin A and vitamin E do not change much.

3

B vitamins

Eggs contain nutrients such as vitamin B1, vitamin B2, niacin, biotin, vitamin B12, etc. The loss of these nutrients in boiled eggs is very small, so there is no need to worry about it.

Raw eggs contain anti-biotin protein, which will affect the body's absorption of biotin. Biotin is involved in the digestion of food. If it is lacking, it may cause perioral dermatitis, conjunctivitis, hair loss, thinning hair, lighter hair color, fatigue and other symptoms. People with severe deficiency may lose their eyebrows, hair and eyelashes within 3 to 6 months. However, most people rarely lack biotin, and most people who eat raw eggs for a long time may suffer from biotin deficiency.

4

Minerals

Eggs are rich in minerals, such as calcium, phosphorus, potassium, and iron, which are relatively stable during cooking and have little impact.

5

Phospholipids, cholesterol

Boiling eggs has little effect on the phospholipid and cholesterol content, but long-term cooking may cause varying degrees of oxidation, which is not good for health.

Although cooked eggs are better for nutrient absorption, they should not be cooked for too long, otherwise the surface of the egg yolk will gradually turn green. This is because during the cooking process, the iron in the egg yolk combines with the sulfur in the egg white to form dark green ferrous sulfide, so the surface of the egg yolk turns 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 the egg yolk, after all, the iron content of an egg is not much and the utilization rate is low, so it doesn't matter.

The tea eggs that have been cooked for a long time in the breakfast shop. Image source: author

I love soft-boiled eggs, this point cannot be ignored

Soft-boiled eggs mostly refer to eggs whose egg white has solidified and whose yolk is semi-fluid or semi-solid. They have a smooth and delicious taste and are very popular.

Copyright images in the gallery. Reprinting and using them may lead to copyright disputes.

From a nutritional perspective, anti-trypsin and anti-biotin proteins are mainly found in egg whites. For foods like soft-boiled eggs, the anti-nutritional components are almost eliminated as long as the egg white is coagulated. At the same time, the egg yolk is not overheated. In this way, the nutrients in the egg yolk are better preserved and the cholesterol is almost not oxidized, making it a relatively healthy food.

However, people who like to eat soft-boiled eggs really need to be vigilant, as they may get food poisoning. This is because improperly cooked eggs may carry salmonella and other bacteria, increasing the risk of food poisoning.

Salmonella is a bacteria that can exist in the intestines of humans and animals and is commonly found in animal-derived foods, including eggs, meat and raw milk. There are two ways for Salmonella to infect eggs: first, it may be infected by infected hen reproductive tissue before the eggshell is formed; second, it may be contaminated by feces on the eggshell. Eggs are not completely "sealed" and are covered with small holes on the surface. Bacteria can easily penetrate the egg shell and penetrate into the egg.

Don't underestimate salmonella. Infection with it can cause abdominal pain, diarrhea, vomiting, and even death. However, it is not heat-resistant and will die immediately when heated to 100℃, and it will be destroyed at 60℃ for 15 minutes.

Generally speaking, when the yolk temperature reaches 60°C, it will become opaque, and when it reaches 74°C, it will gradually solidify. Therefore, if the egg white of the soft-boiled egg you eat has solidified and is soft, while the yolk is still in a liquid and flowable state, it means that the temperature of the center of the yolk may not reach above 60°C, and it is difficult to kill Salmonella.

Therefore, for food safety, it is recommended not to eat eggs raw, and it is better to cook them as much as possible . Friends who really like to eat soft-boiled eggs must pay attention to the following two points:

1

Note how to save

Eggs that can be eaten raw generally need to be stored at 0~10℃, and it is best to seal them individually and store them in the refrigerator.

2

Keep an eye on the expiration date

This is because although eggs have shells, they are not sealed and are covered with small holes on the surface, which cannot be guaranteed to be completely sterile. Long-term storage or improper storage methods will lead to bacterial growth.

Summarize

Soft-boiled eggs have a unique and delicious taste, but if you are careless, it will increase food safety risks. Friends who don't like to "worry" should just eat hard-boiled eggs! Raw eggs at room temperature are put into the pot after the water boils. Boil for 8 to 9 minutes for a better state and taste. Everyone has different tastes, so you can choose the boiling time according to your own preferences.

If the eggs are just taken out of the refrigerator, it is recommended to put them in cold water, start timing 3 minutes after the water boils, then turn off the heat without opening the lid, and simmer for 5 minutes.

References

[1] Yang Yuexin. Chinese Food Composition Table 6th Edition Volume 2[M]. Peking University Medical Press, 2019

[2]Evenepoel, P et al. "Digestibility of cooked and raw egg protein in humans as assessed by stable isotope techniques." The Journal of nutrition vol. 128,10 (1998): 1716-22. doi:10.1093/jn/128.10.1716

[3] Sun Changhao. Nutrition and Food Hygiene. 8th edition. People's Medical Publishing House. 2018

[4] Wang Xiangdong, Xu Jianguo, He Junyan. Study on the influence of egg cooking process on FeS formation in products[J]. Food Science, 2006(10):366-369.

[5]https://www.cfs.gov.hk/sc_chi/programme/programme_rafs/programme_rafs_fm_01_22.html

[6] Wang Xueshuo, Cui Shenghui, Xing Shuxia, Ding Hong. Hazard analysis, contamination investigation and prevention of Salmonella in catering food[J]. Chinese Pharmaceutical Affairs, 2013, 27(09): 974-979. DOI: 10.16153/j.1002-7777.2013.09.006.

[7] Written by Nathan Myhrvold, Chris Young, and Maxime Billet; Photographed by Ryan Matthew Smith and Nathan Myhrvold; Translated by the Modernist Cooking Translation Team. Modernist Cooking: The Art and Science of Cooking, Volume 4: Ingredients and Preparation [M]. Beijing: Beijing Fine Arts Photography Publishing House, September 2016.

Planning and production

This article is a work of Science Popularization China-Starry Sky Project

Produced by: Science Popularization Department of China Association for Science and Technology

Producer｜China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

Author: Xue Qingxin, registered nutritionist

Review | Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center

Planning丨Yinuo Linlin

Editor: Yinuo