Is eating duck eggs without yolk harmful to human health?

The nutritional content of eggs is relatively comprehensive and balanced. It contains almost all the nutrients needed by the human body. Whether it is egg white or egg yolk, their protein has extremely high physiological value and is easy to digest and absorb. The utilization rate can reach 95%. Above, it is a relatively complete natural food.

How many eggs are good to eat a day? First let’s look at how many nutrients you can get from an egg.

A medium-sized egg, weighing about 50 grams on average, can provide 6 grams of protein, 5 grams of fat, 72 kcal of energy, 23 mg of calcium, 89 mg of phosphorus, 1.2 mg of iron, and 612 international units of vitamin A , thiamine 0.07 mg, riboflavin 0.13 mg, niacin 0.04 mg, cholesterol 300 mg. If we compare an egg with 50 grams of lean meat, the quality of protein and fat in eggs is better than that of lean meat, and the vitamin content is also higher, but the price is cheaper than lean meat. From both nutritional and economic considerations, it is better to eat eggs. More cost-effective.

In recent years, because it has been learned that people with atherosclerosis and coronary heart disease have increased blood cholesterol, many people have become afraid of cholesterol. They are afraid that eating egg yolks will cause arteriosclerosis. So I dare not eat eggs. This concern is unnecessary. Under normal circumstances, cholesterol is not a harmful thing. It is also an indispensable and important substance for the human body. In the body, cholesterol is not only one of the basic materials that make up cells, but also can synthesize several important hormones. , it can also be converted into vitamin d3 in the body.

On the other hand, the cholesterol in human plasma does not all come from food. It comes from both exogenous and endogenous sources. Exogenous sources come from food, and all meat, eggs, and animal fats contain cholesterol. It is estimated that you should eat about 500 milligrams a day. If you eat less animal food, you will not reach this amount. Endogenous cholesterol is synthesized by the body itself, about 1.0 to 1.5 grams per day, which is far more than what is consumed from food, so most of the cholesterol in the body is produced by the body. Under normal circumstances, the body has the ability to automatically adjust. That is, if you eat more cholesterol, less cholesterol will be synthesized in the body; if you eat less cholesterol, more cholesterol will be synthesized in the body. In addition, egg yolk is also rich in lecithin, which is a strong emulsifier. It can make cholesterol and fat particles in the blood smaller and keep them suspended, thereby preventing the deposition of cholesterol and fat on the blood vessel wall and passing through the blood vessel wall. Utilized by body tissues and does not increase plasma cholesterol. Dr. Margaret Flynn of Missouri State University in the United States organized a team to study "eggs and cholesterol" and conducted a six-month experiment on 116 men aged 32 to 62. They first asked the subjects not to eat any egg food for three consecutive months, and measured the serum cholesterol content. Then each person added 2 eggs a day, and then measured cholesterol again after 3 months. The difference between the two results was not obvious, indicating that the subjects The cholesterol content in the body of the patient is not affected by egg cholesterol. Scientists believe that for an elderly person whose blood cholesterol concentration is within the normal range, if he eats two eggs a day, his blood cholesterol will increase by up to 2 mg%. This very small amount will not cause atherosclerosis, and other nutrients in eggs ingredients, but will bring more benefits to people, so there is no need to be afraid of eating eggs. Of course, eating too many eggs is not good either. First, it is a waste of high-quality protein. Second, the protein breakdown products will increase the burden on the liver and kidneys, which is also detrimental to the body. For a person with a normal metabolism, it is good for the body to eat eggs appropriately, such as 1 to 2 eggs a day, or several times a week.

The most nutritious cooking method: There are many ways to eat eggs. In terms of nutrient absorption and digestibility, boiled eggs are 100%, scrambled eggs are 97%, fried eggs are 98%, and fried eggs are 98%. It is 81.1%, 92.5% when cooked with boiled water and milk, and 30% to 50% when eaten raw. From this point of view, boiled eggs are the best way to eat, but be careful to chew them slowly, otherwise it will affect absorption and digestion. However, for children, steamed egg custard and egg drop soup are the most suitable, because these two methods can loosen the protein and be easily digested and absorbed by children.

Note: You should eat less tea eggs, because tea contains acidifying substances that, combined with the iron in eggs, will irritate the stomach and affect the digestive function of the gastrointestinal tract.

Whether the egg white or the yolk is better:

The correct way to eat is to eat the whole egg. The egg white contains more protein, while the other nutrients are more in the yolk. .

Some people believe that eating eggs raw provides the best nutrition.

In fact, eating raw chicken has many disadvantages and is very harmful to human health.

Raw eggs contain anti-enzyme and anti-biotic proteins. The former hinders the contact between protease and protein in the human gastrointestinal tract, affecting the digestion and absorption of protein. The latter can combine with biotin in food to form a substance that the human body cannot absorb. However, the above two harmful substances present in raw eggs are destroyed once cooked and no longer affect the body's absorption of nutrients.

The protein structure of raw eggs is dense and difficult for digestive enzymes in the gastrointestinal tract to access, so it is not easily digested and absorbed. The structure of cooked egg protein becomes soft and easy to be digested and absorbed by the human body.

About 10% of fresh eggs contain pathogenic bacteria, mold or parasite eggs. Some parents use boiling water to boil eggs and add sugar to feed their children. Because the bacteria and parasite eggs in the eggs cannot be completely killed, it can easily lead to diarrhea and parasitic diseases. If salmonella is present in eggs, it can also cause food poisoning. It has recently been discovered that egg shells may contain 0-157 enterohemorrhagic Escherichia coli. Even if the amount of bacteria is very small, if the eggs are raw, it is enough to cause food poisoning. Some people use raw eggs to treat constipation in children. This does not cure constipation, but it can also infect humans and animals with toxoplasmosis. This disease has an acute onset, and almost all organs in the body are invaded by Toxoplasma gondii, causing lesions, and in severe cases, death.

Therefore, eggs must be cooked, preferably steamed eggs. It is not advisable to wash eggs with boiling water, let alone eat raw eggs.

Boiled eggs are one of the common ways to eat them, but if they are not cooked properly, the egg whites will often be cooked but the yolks will be undercooked; or the eggs will be overcooked and the whites and yolks will be very soft. Hard, which is not conducive to digestion and absorption.

The correct method of boiling eggs: put the eggs in a pot of cold water, raise the temperature over slow heat, then boil over low heat for 2 minutes. After stopping the fire, soak for another 5 minutes, so that the egg whites will be tender and the yolks will be solid but not old.

According to nutritionists: eggs with different boiling times have different digestion times in the human body. "3-minute eggs" are lightly cooked eggs, which are easiest to digest and take about 1 hour and 30 minutes; "5-minute eggs" are half-boiled eggs, which take about 2 hours to be digested in the human body; eggs that are boiled for too long will not be digested in the human body It takes 3 hours and 15 minutes.

The "5-minute eggs" are not only soft and tender, but also beneficial to human nutrition. The American medical community published a research report that 24 adults ate two half-boiled eggs a day. After 6 weeks, the blood lipids did not increase, but the good cholesterol (HDL), which is beneficial to the human body, increased by 10%.

Nutritional and eating methods of eggs

Eggs are very nutritious. , a relatively low-priced commonly used food. It has a wide range of food targets, ranging from 4 to 5-month-old babies to the elderly.

1. The nutritional value of eggs

1. Protein

Eggs are rich in high-quality protein. Each hundred grams of eggs contains 12.7 grams of protein. The protein contained in two eggs is roughly equivalent to the protein of 3 ounces of fish or lean meat. The digestibility of egg protein is also highest in milk, pork, beef and rice.

Eggs are particularly rich in methionine, and cereals and beans lack this essential amino acid, so combine eggs with Eating a mixture of cereals or legumes can improve the bioavailability of the latter two.

2. Fat

Eggs contain 11.6 grams of fat per 100 grams, mostly concentrated in the yolk. Among them, most of them are unsaturated fatty acids, and the fat is milky and easy to be absorbed by the body.

3. Other micronutrients

Eggs also have other important micronutrients, such as potassium. , sodium, magnesium, phosphorus, especially the iron in egg yolk reaches 7 mg/100 grams. Infants eating eggs can supplement the iron deficiency in milk. Eggs are rich in phosphorus, but calcium is relatively insufficient. Therefore, milk is used. Food and eggs can be nutritionally complementary to babies. Eggs are also rich in vitamins a, b2, b6, d, e and biotin. Especially in egg yolks, vitamins a, d and e dissolve easily with fat. It is absorbed and utilized by the body. However, the content of vitamin C in eggs is relatively small, so you should pay attention to eating it with foods rich in vitamin C.

2. Is it better to eat egg yolk or egg white?

Egg yolk and egg white proteins are both high-quality proteins and have high digestibility.

However, there are big differences in other nutrients between egg yolk and egg white. Egg white is mainly ovalbumin. In addition to being rich in yolk phosphoprotein, egg yolk is also rich in fat and micronutrients (micronutrients are a general term for vitamins and trace elements). ), especially rich in iron, phosphorus and vitamins a, d, e and b.

3. Do raw eggs have high nutritional value?

Eggs are easily infected by salmonella and other pathogenic microorganisms. Eating raw eggs is prone to digestive system diseases. Raw egg whites contain organic biotin protein. and antitrypsin, which hinder the breakdown and absorption of proteins and biotin. On the contrary, the protein structure of cooked eggs changes from dense to loose, making it easier for the body to digest and absorb. Of course, after overheating, the protein will coagulate excessively, which is not conducive to digestion and absorption.

Egg Myth abc

Myth a: The more eggs the mother eats, the better

The mother consumes a lot of physical energy during childbirth, her digestion and absorption function is weakened, and her liver detoxifies. Function reduction, eating a large amount of eggs will increase the burden on the liver and kidneys, causing adverse consequences. Eating too much protein will also produce a large amount of ammonia, hydroxyl, phenol and other chemical substances in the intestines, which are very toxic to the human body. It is prone to abdominal distension, dizziness, limb weakness, coma and other symptoms, leading to "protein poisoning" syndrome". Protein intake should be calculated based on the body's digestion and absorption functions of protein. Under normal circumstances, it is enough for pregnant women to eat about 3 eggs a day.

Myth b: Eating eggs often leads to high cholesterol

No. Because the egg yolk is rich in lecithin, it is a powerful emulsifier that can make cholesterol and fat particles extremely fine and smoothly pass through the blood vessel wall and be fully utilized by cells, thereby reducing cholesterol in the blood. Moreover, the lecithin in the egg yolk can release choline after digestion, enter the blood and synthesize acetylcholine, which is the main substance of neurotransmitters and can improve brain function and enhance memory.

Myth c: Raw eggs are more nutritious

Eating raw eggs is not only unhygienic, it can easily cause bacterial infection, and nutrients are not easily absorbed. Raw eggs contain avidin, which affects the absorption of biotin in food and can lead to "biotin deficiency" such as loss of appetite, general weakness, and muscle pain. In addition, raw eggs contain "antitrypsin", which will destroy the human body's digestive function. As for those "hairy eggs" that have been incubated but have not yet hatched chicks, they are even more unhygienic.

Deciphering the techniques for cooking eggs

Spreading eggs: Avoid using high heat, otherwise a lot of nutrients will be lost. Because when the temperature is too high, the protein in the eggs will be destroyed and decomposed. Especially fried eggs that are crispy will suffer even greater nutritional losses. But it won't work if the fire is too low. The time is relatively long, the water is lost more, and the eggs are dried out, affecting the texture. Therefore, it is best to use medium heat when spreading eggs.

Steamed egg custard: Whether the egg custard can be steamed well, in addition to adding an appropriate amount of water, mainly depends on whether the egg liquid is stirred well. When stirring, the air should be mixed evenly and the time should not be too long. Temperature is also directly related to the good mixing of egg liquid. For example, when the temperature is below 20℃, the egg whisking time should be longer (about 5 minutes), so that after steaming, there will be holes of different sizes that are invisible to the naked eye; when the temperature is above 20℃ , the time should be appropriately shorter. Do not add oil and salt at the beginning of stirring the eggs, as this will easily damage the egg colloid and make the steamed egg custard thick and hard; if you stir the egg liquid evenly before adding oil and salt, stir it for a few times, then put it into the steamer and take it out of the pot. The egg custard will be very soft.

Beat egg drop soup: Add a few drops of vinegar when the soup is boiling, and the egg juice will appear as beautiful egg drops when it enters the water.

Boiled eggs: The key is to control the time, generally 8 to 10 minutes is appropriate. If it is cooked too raw, the protein will not be loosened and it will be difficult to digest and absorb. If it is cooked too old, the protein structure will change from loose to tight, making it difficult to digest and absorb.

Special Tips

Do not add MSG to scrambled eggs

Eggs themselves contain a large amount of glutamic acid and a certain amount of sodium chloride. If you add MSG, heat them The latter two substances will generate a new substance - monosodium glutamate, the main component of MSG, and the umami flavor of the egg itself will be masked.

Put cold water into the pot, and the water surface must cover the eggs

After the fire boils, turn off the heat and do not lift the lid at this time

Let the eggs soak in the boiling water 5 minutes is enough

The eggs cooked in this way are cooked layer by layer

When you bite into the tender eggs, the yolk inside will be in circles

Exceptionally beautiful and without loss of nutrients

If you want the eggs to be older, soak them for eight minutes. The fishy smell will be less when cooked this way

Nutritional comparison of various eggs

In addition to eggs, common ones include duck eggs, goose eggs, salted duck eggs, pigeon eggs, quail eggs, etc. . Their nutritional components are roughly the same, but there are some subtle differences:

1. Duck eggs contain the highest methionine and threonine.

2. The calcium content in salted duck eggs is twice that of eggs, which is equivalent to the calcium content in pigeon eggs.

3. Goose eggs have the highest fat content, the highest corresponding cholesterol and calories, and are the richest in iron and phosphorus.

4. Although the protein and fat content in pigeon eggs are slightly lower than that of eggs, they contain higher calcium and iron elements than eggs.

5. The protein and fat content of quail eggs are equivalent to those of eggs, but their riboflavin (vb2) content is 2.5 times that of eggs. The carotene in eggs is the most in the yolk of all eggs.

Therapeutic effects of eggs

The dietary effects of egg whites are mainly to moisten the lungs and soothe the throat, clear away heat and detoxify, and are used to treat sore throat, red eyes, diarrhea, malaria and burns; Taking appropriate amounts of breast milk can treat convulsions;

How to steam egg custard? What are some tips?

Steps:

1. Take 2 eggs, break them into a basin, stir them evenly first, then add 200 ml (a small cup) of warm water and 1 gram of refined salt, and stir well. Set aside for later use.

2. Add water to the pot, put the egg basin into the drawer, and steam slowly over low heat until it becomes solid (like tofu brains) and is cooked.

3. After taking it out of the pot, add 0.5 grams of sesame oil and it is ready to eat.

Tips:

1. Apply a few drops of cooked oil on the inner wall of the steamed egg custard basin in advance, so that the egg custard will not stick to the bottom easily.

2. Put the eggs in a basin and stir well before adding water. Otherwise, the egg liquid will not be stirred evenly and the steamed egg custard will easily settle.

3. The key to steamed egg custard lies in the heat. If steamed over strong fire, the egg juice will boil and small holes will appear, which will affect the taste and appearance, so be sure to use a gentle fire.

4. Are eggs high in iodine and zinc good for the human body?

According to relevant experts, so-called high-iodine and high-zinc eggs mostly add zinc, iodine, iron and other trace elements into chicken feed. After chickens eat these feeds, the eggs they lay will have corresponding The content of trace elements is higher than that of ordinary eggs. However, this kind of eggs is only suitable for a small group of people and should not be eaten casually. Excessive intake of certain trace elements can be harmful to the human body. For example, too much iodine in the human body can cause a series of neurological symptoms, while zinc content in the body exceeding a certain level can easily cause calcium, iron, etc. deficiencies