The structure and chemical composition of a chicken egg. Calorie Egg white chicken. Chemical composition and nutritional value Composition of egg white and yolk

Calories, kcal:

Proteins, g:

Carbohydrates, g:

Eggs are familiar and traditional food products, chicken eggs are considered the most common. Laying hens lay one (rarely two) eggs once a day, the most useful are eggs from young domestic hens, they are small in size, but have a pronounced "egg" taste.

Chicken egg calories

calories chicken egg is 157 kcal per 100 grams of product. It should be borne in mind that the average weight of one egg varies from 35 to 75 g, so the calculation of calories will be appropriate.

Harm of chicken eggs

The main harm of chicken eggs is the possible presence of a dangerous microbe in them - salmonella, which causes salmonellosis, which causes severe inflammation intestines, blood poisoning and paratyphoid. Excessive consumption of boiled eggs can cause digestive problems, constipation.

In the chemical composition of chicken eggs there are more than ten basic vitamins - vitamins (,), and, as well as almost the entire table chemical elements Mendeleev -, and, and, boron and, and titanium, silicon, and aluminum, and. There is a lot of iron in eggs, but it is not absorbed very well from eggs, so it is better to use meat and liver as a source of iron. At the same time, if you drink raw eggs, they also prevent the absorption of iron from other foods.

A chicken egg consists of protein and yolk. - a supplier of natural, easily digestible protein, on average, protein contains 10 g per 100 g of egg white. contains fat-soluble vitamins and cholesterol.

Egg yolk contains a high amount of fat, but it is mainly polyunsaturated fatty acid and monounsaturated fatty acids, saturated fatty acids account for a smaller % content:

Polyunsaturated fatty acids:

Linoleic acid - 16%
Linolenic acid - 2%

Monounsaturated fatty acids:

Palmitoleic acid - 5%
Oleic acid - 47%

Saturated fatty acids:

Palmitic acid - 23%
Stearic acid - 4%
Myristic acid - 1%

One egg contains about 130 mg of choline. Choline, which is part of the yolk, regulates the amount of fat and cholesterol in the body.

Part of the chicken egg, improves blood flow to the brain, which improves memory and prevents the development of sclerosis (calorizator). Even egg shells, washed, peeled and dried, are very useful product to strengthen bones and stimulate hair growth.

In the composition of eggs, the cholesterol content reaches - 570 mg. Cholesterol is found only in the yolk and it is considered the least harmful, because it is balanced by lecithin, which in turn is necessary for the nutrition of nerve cells.

Nutritionally, an egg replaces two hundred grams of milk and fifty grams of meat. Chicken eggs must be consumed several times a week, they are almost completely absorbed by the body (by 97-98%), without clogging the intestines with unnecessary toxins. Although eggs are considered a very nutritious food, they do not get better. Moreover, they are often included in therapeutic diets.

Egg and cholesterol

In a day healthy person 1 egg is allowed. If a person has elevated level cholesterol in the blood, then nutritionists recommend eating 2-3 eggs per week.

Categories of chicken eggs

Chicken eggs sold from poultry farms are labeled depending on the shelf life and weight of an individual egg. Usually on the package we see a letter and a number, or two capital letters, find out what they mean.

The first is a sign indicating the shelf life of the product:

D - dietary egg, the implementation period does not exceed 7 days,
C - table egg, allowable implementation period - 25 days.

By weight, chicken eggs are divided as follows:

B - egg the highest category, weighing 75 g and above,
O - selected egg, 65-74.9 g,
1 - egg of the first category, 55-64.9 g,
2 - egg of the second category, 45-54.9 g,
3 - egg of the third category, 35-44.9 g.

Differences in chicken eggs in appearance

Chicken eggs, even in one package, can look completely different - almost round and elongated, with a pronounced sharp tip or almost perfect oval shape, white, cream, light brown, with dark spots, matte and glossy, smooth and rough to the touch. For quality and taste features this does not affect in any way, usually white eggs are laid by white hens, and colored eggs are laid by laying hens bright colors. Therefore, choosing eggs various colors First of all, we give preference to our aesthetic predilections. Often there are eggs with two yolks - until now, scientists have not come to an unambiguous conclusion whether this is a pathology or a common thing. For serving, such eggs are very effective, and differ from ordinary ones in an enlarged shape.

There are several options for how you can find out about the freshness of eggs. But knowing such a thing that the longer the egg is stored, the easier it becomes, we chose the simplest option - dip the egg into a glass of water. If the egg drowned, then it is the freshest, 1-3 days after the chicken laid it, if the egg floats, but does not rise high, then this means that the chicken laid the egg about 7-10 days ago. And if the egg is left floating on the surface of the water, the chicken laid such an egg more than 20 days ago.

Each egg is covered with a film from nature, which allows the eggs to be stored for a long time, so it is not recommended to wash it off before storing the eggs, but before the process of cooking the eggs, it is better to wash off the film with water.

Chicken egg and weight loss

Many have heard about the benefits of chicken eggs and their beneficial effects on the process of losing extra pounds. "Two boiled eggs for breakfast - overweight as it happened" - a familiar slogan, right? If you think about it carefully, it's not so simple. Recall that athletes-bodybuilders, who are critical of any product, consume only proteins during the “drying” period of the body, ignoring the yolks in order to get pure protein and get rid of cholesterol. Therefore, before unconditionally believing in quick weight loss on chicken eggs alone, you need to understand whether it is so useful. However, there are those that are based on the use of chicken eggs and lead to real weight loss.

Cooking chicken eggs

Probably, there is no simpler and more necessary product in nature and in our refrigerator than a chicken egg. Starting with a raw egg, which is drunk, seasoned with pepper and beaten into eggnog, to soft-boiled eggs, in a bag, poached and hard boiled. Fried eggs, simple omelettes, with bacon and fillings, puddings and egg muffins, fillings for pies, meatloaf and pancakes, an indispensable ingredient in almost all your favorite salads, cold appetizers, desserts - meringues and almond cakes, dough additives and colored eggs for Easter - the list can be continued indefinitely, because chicken eggs are a universal product that are boiled, fried and baked in the oven, eaten raw and in any case, except for pleasure, they get the maximum benefit.

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How many proteins, fats and carbohydrates are contained in one chicken egg? And how much separately in the yolk and protein?

It is important to know when the diet is limited to the choice of products for weight gain or on a diet, because the protein is not completely absorbed from the products, and here it is not enough to count for long.

Let's try to figure it out.

Let's start with the fact that eggs are dietary, marked with the letter D and canteens marked with the letter C - these designations only speak of shelf life.

Eggs are considered dietary if they can be stored for no more than 7 days. Therefore, look at the packing date when buying eggs. Everything that is stored for more than 7 days, but not more than 25 days, is table eggs.

Egg categories are defined as follows

The highest category (B) - 75 g or more,
Selected egg (O) - from 65 to 74.9 g,
The first category (1) - from 55 to 64.9 g,
The second category (2) - from 45 to 54.9 g,
The third category (3) - from 35 to 44.9 g.

The highest category is quite rare on sale, the third - even rarer. All other names of eggs: rejuvenating, rustic, this is about nothing - a marketing ploy, supposedly they have more selenium and others useful elements. But no one has done it yet clinical trials, the influence of such eggs on the rejuvenation of a person or his health. And it is important for us to know only the composition of BJU (proteins, fats and carbohydrates) and calorie content.

I buy a package, inspect it, the composition of the product per 100 g of weight is written on the package. On the package with eggs, the composition is written: protein 12.7 g, fat 11.5 g, carbohydrates 0.7 g, calorie content 157 kcal. Poultry farms analyze their products, and I hope that these data can be trusted.

All eggs appear to be the same size, but this is only at first glance.

I weigh, the smallest egg weighs 66 g, the largest 72 g - and if you look closely, you can see that it is larger. I choose these two eggs from the whole package and will calculate the average values from them.

Carefully break and separate the yolks from the whites. I weigh on electronic scales (error + - 1 g).

The shell weighs 8 g for an egg, which is 72 g, for the rest of the eggs, which are 66-68 g each, the shell weighs 7-8 g. The yolks weigh 18-20 g. Proteins average 42-43 g.

Now let's turn to the nutritional value of chicken eggs. On different sites and nutrition calculators, the information is contradictory. I am trying to find something that sheds light on this confusion and compare it with institute textbooks, for example, on the commodity science of food products (Kazantseva N.S.). So, according to theory, chicken egg protein contains in its composition on average: water 80-85%, proteins 12-13%, carbohydrates about 0.7%, minerals 0.6%, fat 0.3%.

I remember what was written on the packaging of my specific eggs.

100 g of the edible part of the egg contains 12.7 g of proteins, then

64 g egg without shell (72g-8g) - 8.13 g proteins (amino acids),

59 g egg without shell (66g-7g) - 7.5 g proteins (amino acids).

The average amount of proteins (amino acids) is 7.8 g per egg.

We check according to the theory: The protein part of the eggs consists of approximately 13% of proteins (amino acids), which means that in 43 g of my egg protein there are approximately 5.6 g of amino acids. In a smaller egg, 42 grams of protein contains approximately 5.4 grams of proteins. The average is 5.5 g of proteins. This is the figure I will write down in my nutrition calculator. By the way, 0.7% protein carbohydrates are 0.3 g, the amount of fat in the protein is 0.13 g, and the calorie content is 25 kcal.

We can boil or fry this egg, and in any form it will contain all the same 5.5 g of protein and 0.3 carbohydrates. But if we fry it in oil, the BJU changes.

Now the yolks. Chemical composition yolks are more vague: according to some data, the yolk contains about 31.8% fat, 16% protein, 0.2% carbohydrates, 1.1% minerals, and 50% water.

According to others - up to 33% fat, if you turn to Wikipedia, which refers to USDA National Nutrient Database data, so chicken yolks weighing 17 g contain 4.51 g of fat - this is 26.5% - very little, some of the wrong chickens in America, not like ours!

In general, I am again guided by the nutritional value declared on the packaging of those eggs that I bought. It says 11.5 g per 100 g of egg weight. If you remember, fats are contained not only in the yolk, but in the yolk and protein, there is nothing in the shell except calcium salts.

For 100 g of the edible part of the egg, there are 11.5 g of fat, then

64 g of egg without shell accounts for 7.36 g of fat.

For 59 g of egg without shell, 6.7 g of fat. The average is 7 grams of fat per egg.

How to distribute it all between protein and yolk? It's simple here: all the data on the amount of fat in the egg protein, according to different sources, are approximately the same - 0.3% fat. I have already calculated that this is 0.13 g of fat. Then the yolk accounts for an average of 7-0.13=6.87 g of fat.

16% of the protein from the total mass of the yolk is on average 3g (I count between eggs weighing 72 and 66g). A 0.2% carbohydrates 0.038 g. Average calorie content 74.3 kcal.

By the way, at the expense of caloric content, everywhere they write, then the yolk has it three times higher than that of the protein. Let's compare 25 kcal and 74.3 kcal - the difference is 2.9 times, so that's right!

Summing up, according to my calculations the nutritional value table eggs of selected category.

	Weight, g	Proteins, g	Fats, g	Carbohydrates, g	kcal
Nutritional value of the product	100	12,7	11,5	0,7	157
Whole egg C0	59-62	7,8	7	0,34	99
Protein 1 egg C0	42-43	5,5	0,13	0,3	25
Yolk of 1 egg С0	18-20	3	6,87	0,038	74,3

What do you want to say in the end. Of course, the difference in the chemical composition of chicken eggs is sometimes different. You can take any to calculate your diet - averaged from various nutrition calculator sites, or from a package of purchased eggs. In fact, it is worth believing rather the information that is written on the package with eggs. The fact is that the chemical composition of eggs depends on the breed of chickens, on their age, and other factors that are individual at each poultry farm.

Chicken eggs- an indispensable product in our diet. Not a single feast is complete without eggs, it is a staple in many dishes and pastries, and is also used for cosmetic and medical purposes.

Composition of a chicken egg

A chicken egg weighs approximately 58 grams, consists of a shell, protein and yolk.

The shell makes up about 10% of the egg, it may have white or Brown color which depends on the breed of chicken.
Protein makes up most of the egg, namely 60%. Protein mainly consists of both water and protein compounds such as ovalbumin, conalbumin, ovomucoid, globulin and others.
The yolk is the core of the egg containing all the vitamins and minerals, it takes up 30% of the egg. The yolk contains fat-soluble vitamins, including vitamin D, as well as cholesterol.

Chicken egg calories and nutritional value

Demand for eggs never falls, which gives a stable profit to many poultry farms and personal subsidiary plots. It's no secret that an egg obtained in household, has great value, nutritional value and usefulness. On average, one person eats 290 eggs a year; people value eggs not only for their nutritional value, but also for their taste.

Nutritional value of 1 chicken egg:

proteins 12.5 grams
fats 11.5 grams
carbohydrates 0.8 grams
water 74 grams
fatty acids 2.5 grams
ash 1-1.5 grams
monosaccharides and disaccharides 0.6 grams.

The calorie content of the product is 158 kcal.

In addition to the above, the chicken egg contains many macro and microelements such as:

phosphorus 190 mg
potassium 140 mg
magnesium 11 mg
calcium 54 mg
sodium 135 mg
chlorine 155 mg
sulfur 177 mg
iron 2.6 mg
zinc 1 mg
iodine 21 mg
fluorine 54 mg
copper 83 mg

Chicken egg is rich in fat-soluble as well as water-soluble vitamins:

vitamin A 0.24 mg
vitamin E 2 mg
vitamin B2 0.43 mg
vitamin PP 0.20 mg
vitamin B12 0.53 mg
vitamin K 0.31 mg
vitamin B9 7 mg
vitamin D 2.3 mg

Useful biologically active and nutrients in a chicken egg for a person they play a huge role, restore tissues and kill harmful pathogenic microorganisms.

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Useful properties of chicken eggs

As already mentioned, a chicken egg is very useful and even necessary for the human body, it has a number of useful properties Let's look at them in more detail:

Strengthens immune system , helps fight viruses, saturating the body essential vitamins and minerals.
Reduce the risk of malignant compounds and oncological diseases.
Takes care of the cardiovascular system.
Strengthens vision and restores optic nerves, prevents eye diseases.
Good for bones and muscles promotes the absorption of calcium and proper growth bones.
Restores muscle tissues , thanks to the protein - protein, increases endurance.
Increases brain performance, improves memory and develops intelligence.
Strengthens nervous system , relieves tension, improves mood.
Recommended for pregnant women and lactating mothers, are quickly absorbed, and promote lactation. Also, chicken eggs are useful for women planning pregnancy, as they contain folic acid.
Promotes sperm activity and useful to men in planning offspring.
Fights ulcers and improves the functioning of the gastrointestinal tract.
Improve hair color and texture.
Promotes weight loss, recommended for consumption for breakfast in boiled form.

Harm of a chicken egg - truth or myth?

A chicken egg can really harm the human body, but only because of non-compliance with sanitary standards, overuse or individual health contraindications:

Cholesterol
Cholesterol is not always harmful to our body, but in correct proportions even useful. AT egg yolk a lot of cholesterol and you can not eat them in large quantities. Cholesterol will not harm the body. If you eat no more than 2 yolks per day or limit yourself to eating only egg white. For neutralization bad cholesterol you can eat with eggs such foods as plums, raisins, cabbage, beans, oranges, spinach.
salmonella virus
The risk of bringing salmonella into human body very large if used raw eggs and do not wash them before cooking. Salmonella does not harm the egg, it is contained in the egg shell and protein. When a virus enters the human body, it can cause a number of serious illnesses such as blood, intestinal and typhoid infections.
Diabetes
Chicken eggs are contraindicated for diabetics, and their use can lead to a heart attack or stroke.
Allergy
Allergy to chicken eggs is a rare phenomenon. But with individual intolerance to eggs, you can cause acute reaction organism.

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Egg category

Chicken eggs are classified according to weight, there are 5 main categories:

(SV) the highest category. These are the largest eggs weighing from 75 grams.
(OV) selected egg. Enough large eggs from 65 to 74.9 grams
(С1) first category. A clean, even shell and a strong yolk, an egg weighing from 55 to 64.9 grams.
(C2) second category. The egg is small from a young hen, weighing from 45 to 54.9 grams.
(C3) third category. The smallest chicken egg in size and weight is from 35 to 44.9 grams.

In addition to the standard classification, eggs can differ in additional types: have two yolks, be enriched with iodine or selenium, dietary eggs. Remember that an egg is considered dietary only up to 7 days of storage. After 7 days, this egg is considered a table egg.

How long to boil chicken eggs?

Boiling chicken eggs is simple: place the egg in cold salted water and put on fire. People boil eggs depending on the desired consistency, hard-boiled or soft-boiled eggs.

On average, boiling an egg takes from 3 to 10 minutes:

If you boil an egg for 3 minutes. After three minutes, the egg cannot be considered ready, rather raw. The protein in such an egg is still soft, and the yolk is very liquid.
If you boil an egg for 5 minutes. After five minutes, the egg is considered half cooked. The protein in the egg will be ready and hard, but the yolk will be watery. Such an egg is truly called soft-boiled.
If you boil an egg for 7 minutes. Seven minutes of boiling will make the egg ready, but not yet hard-boiled. The egg will be soft, but easy to peel and not fall apart when pressed.
If you boil an egg for 9 minutes. It is after 9 minutes of cooking that the egg can be considered cool with confidence. Now it is important not to overcook the egg, otherwise the yolk will turn blue and taste like rubber.

Can you lose weight by eating chicken eggs?

Eggs are very useful for dietary and proper nutrition, therefore, with the help of eggs, you can lose weight if you follow certain rules:

Eggs should be eaten boiled without adding salt for breakfast. They are easily digested and guarantee a long feeling of satiety.
Before breakfast, drink warm water, 1-2 cups on an empty stomach.
Eat fruits with eggs, citrus fruits and berries are especially effective for weight loss.
Do not mix egg and potato consumption, since starch is poorly absorbed with egg white. It is better to replace potatoes with some vegetable.
Try the 3 Day Egg Diet for Fast Weight Loss. During the diet, you can only eat eggs and citrus fruits, drink water and green tea. A day you need to eat 2-3 eggs and 4 fruits. The result of the diet can be a weight loss of 2-3 kg.

Eggs are a biologically valuable product that can and should be eaten. They will help keep strong bones, lose weight and regain youth. In the event of any painful symptoms after eating eggs, you should consult a doctor.

Now I don't have to worry about being overweight!

This effect can be achieved in just a few months, without diets and exhausting workouts, and most importantly - with the preservation of the effect! It's time for you to change everything! The best complex weight loss of the year!

Chicken eggs are a product that is present on the menu of almost every person. They can have a dark and light shell color - it depends on what breed the chicken was that laid the egg. But the color of the shell in no way affects the quality characteristics of the product.

The size of a chicken egg depends on several factors.:

the age of the bird;
the food she eats;
chicken breed;
conditions of detention.

We recommend reading:

In any case, chicken eggs have certain beneficial properties - they are due to the chemical composition of the product.

Nutritional value of 100 g:

Calories: 157 kcal
Proteins: 12.7 gr
Fat: 11.5 gr
Carbohydrates: 0.7 gr

Water: 74.1 gr
Saturated fatty acids: 3 g
Cholesterol: 570 mg
Mono- and disaccharides: 0.7 g
Ash: 1 gr

vitamins:

Vitamin A: 0.25 mg
Vitamin PP: 0.19 mg
Vitamin E: 2 mg
Beta-carotene: 0.06 mg
Vitamin A (RE): 260 mcg
Vitamin B1 (thiamine): 0.07 mg
Vitamin B2 (riboflavin): 0.44 mg
Vitamin B5 (pantothenic): 1.3 mg
Vitamin B6 (pyridoxine): 0.14 mg
Vitamin B9 (folic): 7 mcg
Vitamin B12 (cobalamins): 0.52 mcg
Vitamin D: 2.2 mcg
Vitamin E (TE): 0.6 mg
Vitamin H (biotin): 20.2 mcg
Vitamin K (phylloquinone): 0.3 mcg
Vitamin PP (Niacin equivalent): 3.6 mg
Choline: 251 mg

Macronutrients:

Calcium: 55 mg
Magnesium: 12 mg
Sodium: 134 mg
Potassium: 140 mg
Phosphorus: 192 mg
Chlorine: 156 mg
Sulfur: 176 mg

trace elements:

Iron: 2.5 mg
Zinc: 1.11 mg
Iodine: 20 mcg
Copper: 83 mcg
Manganese: 0.029 mg
Selenium: 31.7 mcg
Chromium: 4 mcg
Fluorine: 55 mcg
Molybdenum: 6 mcg
Cobalt: 10 mcg

Do you know that the product in question is the only one that is absorbed by the human body almost completely (by 97-98%)? And at the same time, the chemical composition of a chicken egg contains all the vitamins and minerals necessary for normal life. Here are just a few of them:

lecithin - found in the yolk, contributes to the normalization of brain cells, the dissolution of existing plaques in blood vessels, and improves liver function;
luten - significantly improves the level of vision;
- strengthens bone tissue;
choline - is the prevention of cancer;
niacin - affects the formation of germ cells, increases the efficiency of the brain;
- necessary during pregnancy.

Separately, it should be said that the benefits of a chicken egg for the human body lie not only in protein and yolk. The shell is very useful with a high content of calcium - it can also and even needs to be eaten. Of course, no one says that you can just take and gnaw it, you have to cook it natural medicine to strengthen bones and normalize metabolic processes. To do this, thoroughly wash the shell, boil in water for 10 minutes, dry and grind to a powder. And in this form, you need to consume 3 grams of shell from chicken eggs daily, and in order for calcium to be better absorbed, you need to add 2-3 drops of lemon juice to the daily dose of the “medicine”.

The calorie content of chicken eggs is high - 157 kcal per 100 g of product. It is not for nothing that boiled chicken eggs were given (and are given) for breakfast in kindergartens and schools - they are easily perceived by the body, the stomach does not become crowded, but there are enough calories for both physical and mental activity.

The benefits of chicken eggs

The fact that the product in question is really useful for the human body is not questioned by any of the scientists and doctors. Judge for yourself what happens to the body with regular and moderate (!) Eating chicken eggs:

bone tissue is strengthened - this is especially important in childhood and old age;
prophylaxis is carried out;
corrects the work of the liver in case of simple diseases;
improves the condition of the walls blood vessels- removes plaques from there, makes the walls more elastic;
serves as a prevention of breast cancer;
favorably affects the intrauterine development of the fetus;
increases the efficiency of the brain, improves memory;
significantly increases concentration of attention even during prolonged mental activity;
protects ophthalmic nerve from weakening;
is the prevention of cataracts.

In addition, by eating 2 chicken eggs every day, a person provides his body daily dose vitamins and minerals.

Harm of chicken eggs

The debate about the benefits and harms of the product in question has been going on for several decades. Of course, in spite of everything positive traits chicken egg, it also has its drawbacks - this is exactly the harm that may be done to the body.

Avoid ingestion too a large number"Bad" cholesterol from chicken eggs can also be done by separating the protein from the yolk. In this case, only protein, which does not contain cholesterol in its composition, will go into food.

Secondly, many scientists and doctors point out how harmful property chicken eggs risk of infection. it infection absolutely does not play a role in the health of the chicken or the quality of the egg, but when it enters the human body, it provokes the development of very complex, sometimes deadly, diseases.

And this issue can be solved if you adhere to the following rules:

But in general it is worth knowing - in recent times the risk of contracting salmonellosis from chicken eggs has been significantly reduced. This happened due to vaccination activities at poultry farms.

Thirdly, the chicken egg is recognized as an allergenic product. Indeed, people often have characteristics allergic reaction- small rashes, redness of certain areas of the skin, itching. But it needs to be clarified:

Allergy to eggs most often manifests itself in children at a younger age and by the age of 5-7 years passes without a trace.
Even if there is an allergy in adulthood, then only the yolk of an egg can be consumed - the protein contains a huge amount of protein, which serves as a provocateur of an allergic reaction.

And there is one more thing - when diagnosed, chicken eggs can provoke the development of myocardial infarction or stroke. But even in this case, there is no categorical ban on eating the product in question - there is only a recommendation not to allow it to be consumed excessively.

Some features of the choice of chicken eggs

In stores, you can often see chicken eggs with different markings - sometimes it is red, sometimes blue, with some letters and numbers. What does it all mean and what should be guided by when buying the product in question?

Diet egg - not stored at a negative temperature, the implementation period is only 7 days. Dietary is not some sort / type / type of chicken egg, it is simply a designation of “increased freshness”. This is how red ink markings are applied to a dietary egg.

Table egg - the product has already passed the “dietary” stage, that is, at least 7 days have passed since the egg was laid by the chicken. This does not mean that the product has lost some of its useful properties, just a table chicken egg is stored and sold according to different rules. These eggs are stamped with the date of laying in blue ink. Table eggs are stored at room temperature for no more than 25 days, and in the refrigerator - no more than 90 days.

Another point to consider when buying the product in question is the category of eggs. There are 3 main categories:

Category 1 - egg weight ranges from 55-64 g;
Category 2 - the egg will already weigh 45-55 g;
Category 3 - weight below 45 g.

There is another category, denoted by the letter "B" - the eggs are very large, each reaches a weight of 75 grams. But such an egg is practically not found on store shelves. But the selected chicken egg is well known to consumers. The weight of such an egg is somewhat larger than that of the same product of category 1.

Chicken eggs are a healthy product. And listen various versions about how harmful / useful they can be for a long time. We note that if you use the product in question moderately, do not get carried away, then the body will definitely benefit much more than harm.

In the composition of eggs attracts attention high level balance of biologically active components. The chemical composition of eggs is given in the table.

Squirrels

The quantity and quality of protein in the protein and yolk are different. The egg white contains mainly ovoalbumin - 69.7%, conalbumin - 9.5%, ovoglobulin - 6.7%,%, ovomucoid - 12.7%, ovomucin - 1.9%, lysozyme - 3% and avidin - 0.0 5%. Of these proteins, ovoalbumin and conalbumin, which is a flavoprotein, are of the greatest biological value.

The presence of ovoglobulin ensures the ability of egg whites to form foam when churned, and the presence of ovomucin ensures the stabilization of this foam. The yolk contains phosphoproteins - vitellin, livetin and phosphovitin.

The main protein of the yolk is vitellin, the content of which reaches 80%. The amino acid composition of egg proteins (white and yolk) is shown in the table.

The chemical composition of eggs

It can be seen from the table that essential amino acids are well represented not only in the yolk proteins - vitellin and livetin, but also in egg white proteins - ovoalbumin and conalbumin, which, along with vitellin, are an important source of plastic materials for the organism developing in the egg. Avidin, which is contained in egg white, has the ability to actively bind to biotin (vitamin H) and form a biologically inactive biotin-avidin complex, leading to the development of a vitamin deficiency state. It should be noted that another egg white protein, lysozyme, which has antibiotic properties, is very close in structure to the avidin-biotin complex, and these compounds may be identical.

Fats

The egg contains 10% fat, which is completely concentrated in the yolk (99%). One third of the egg fat is represented by lipoids (phospholipids), the other two thirds are neutral fats(triglycerides).

Amino acid composition of egg proteins

Amino acid	The content of amino acids in % of proteins in
Amino acid	whole egg	egg albumin	conalbumin	ovomucoid	vitelline	Livetine
Valine	7,3	7,1	8,2	6,0	1,0	9,8
Leucine	9,2	9,2	8,8	5,1	9,9	10,6
Isoleucine	8,0	7,0	5,0	1.5	-	-
Phenylalanine	6,3	7,7	5,7	2,9	2,5	3,0
Tyrosine	4,5	3,7	4,6	3,2	5,1	5,2
tryptophan	1,5	1,2	3,0	0,3	1,4	1,5
Threonine	4,9	4,0	5,9	5,5	4,9	-
cystine	2,4	0,5	3,8	6,7	1,2	3,1
Methionine	4,1	5,2	2,0	1,0	2,9	2,4
Arginine	6,4	5,7	7,6	3,7	7,7	5,8
Histidine	2,1	2,4	2,6	2,2	1,6	1,2
Lysine	7,2	6,3	10,0	6,0	5,1	6,0
Aspartic acid	-	9,3	13,3	13,0	2,1	3,1
Glutamic acid	-	16,5	11,9	6,5	12,2	7,0

The composition of the latter is dominated by unsaturated fatty acids (67%), which gives all egg fats high biological properties. Egg lipids contain phospholipids, sterols and cerebrosides. The main part of phospholipids is lecithin, the amount of which in the yolk is 8.6% or 1.6 g. Lecithin contains up to 75% choline; about 50% of the lecithin in the yolk is associated with vitellin. In addition to lecithin, the yolk contains cephalin and sphingomyelin, which have the same biological activity as lecithin. The main sterol of the egg yolk is cholesterol, the content of which in the egg is stable and, according to some sources, is 468 mg% (Sisley, 1958). According to other sources, the yolk contains 0.3 g of cholesterol.

The cholesterol in the yolk is found predominantly in free state(84%) in mobile, unbound form. The ratio of lecithin - cholesterol in the egg is favorable, and like in no other food product the content of lecithin exceeds the content of cholesterol. The ratio of lecithin to cholesterol in the yolk of an egg is 6:1.

vitamins

Eggs are one of the important sources of choline. No other food product contains such an amount of choline as eggs - 1700 mg%. Eggs contain all fat-soluble vitamins (in mg%): retinol - 0.6; vitamin D2 - 0.042-0.12; tocopherols - 20; vitamin K - 0.02.

Vitamins of the Β group are quite fully represented (in mg%): thiamine - 0.14 (in the yolk 0.35-0.48); riboflavin - 0.69; pantothenic acid in a whole egg - 1.4, in the yolk - 6; folic acid- 0.09; pyridoxine - 0.02; biotin (vitamin H): in the yolk 0.037, in the protein -0.01, in the whole egg -0.02. In crude protein, biotin is bound to the protein avidin. The ability of avidin to bind biotin causes the occurrence of disorders such as food poisoning after eating raw egg whites. These disorders can be considered as biotin avitaminosis.

The yolk of the egg contains a significant amount of carotenoids, giving it a yellow color. Among the carotenoids here are α- and β-carotene, xanthophyll and cryptoxanthin. Xanthophyll is 3 times more than carotene.

mineral elements

Eggs are the most important source

phosphorus (470 mg%, yolk)
sulfur (220 mg%)
iron (5.8 mg%)
copper (0.4 mg%)

Calcium carbonate is well represented in the egg shell (93% by weight of the shell). There is evidence of good absorption of calcium salts eggshell. Fine eggshell flour can in some cases be successfully used in the enrichment of culinary and bakery products calcium.

The digestibility of a heat-treated egg is better than that of a raw one. Under the influence of heating to a temperature of 80 °, the antitriptic enzyme present in the raw egg is destroyed, and the unfavorable avidin-biotin complex is also cleaved. All egg components are subjected to heat treatment and are well absorbed: proteins - by 98% and fats - by 96%.