For their quality / price ratio, eggs represent an excellent food, boasting remarkable nutritional properties at a minimal expense. We know better the characteristics and nutritional profile of eggs.
Hard-boiled, soft-boiled, scrambled or in the form of an omelette: unless you follow a vegan diet, raise your hand if you don’t keep at least one pack of eggs in the fridge, one of the most common and used foods all over the world.
Understanding why it is easy to say: we are talking about a food that is easily available and really very versatile, satiating, above all it is the best and most convenient protein food available. The emphasis must be placed on the proteins defined as noble and of high biological value, such as to make eggs among the main food choices even in athletes. Let’s explore the properties and nutritional values of eggs below.
What do eggs contain: nutritional values and calories
From a legislative point of view, when we talk about eggs we always refer to those from hens produced on the farm, unless there are different specific indications.
With an average weight of about 60 g divided between egg white (between 35 and 40 g), yolk (between 14 and 18 g) and shell, eggs provide about 130 calories per hectogram (the calories of a single egg are about 85 ), 13 g of protein, 0.7 g of carbohydrates and 9 g of fat.
Of the latter, about 3 g are represented by saturates, but it is above all the cholesterol present (only in the yolk) that has been accused: with its 358 mg per hectogram, in fact, with just one egg the recommended daily amount is exceeded. from the food guidelines. This has for a long time demonized the frequent weekly consumption of this precious food, considering it co-responsible for the onset of cardiovascular diseases; theory, then, proved to be incorrect.
The fats in the egg are found only in the yolk, the most full-bodied part of the egg, for about 27% of the total, and are mostly made up of saturated fats and cholesterol, but there is also lecithin, a phospholipid that stimulates HDL activity; they are, instead, totally absent of the albumen, constituted for about 90% of water and for the rest of proteins, vitamins and mineral salts.
Egg proteins are the best possible, possessing a complete amino acid profile since it is composed of essential amino acids, necessary for the construction of cellular structures, but not synthesized by the body independently, except through the introduction of food. Since this composition is as close as possible to the proteins to be synthesized, it is said that eggs contain proteins of very high biological value, greater than those of both animal and vegetable origin.
A single egg provides about 7 g of protein; this value does not change according to cooking, so even a hard-boiled egg always provides 7 g of protein. Since the albumen is essentially formed almost exclusively of water, it represents a “pure” protein source; the proteins present there are defined albumins and among them are ovalbumin, ovotransferrin, ovoglobulin, avidin, responsible for the lack of absorption of vitamin H (or biotin), and lysozyme, with an antibacterial function.
Finally, the egg does not lack mineral salts, such as iron, magnesium, calcium, sodium. We see below the table showing the nutritional values of the egg.
Nutritional values per 100g of egg:
- Waterfall: 77.1 g
- kcal: 128
- Proteins: 12.4 g
- Fat: 8.7 g
- Carbohydrates: 0.7 g
- Fibers: 0 g
- Sodium: 137 mg
- Potassium: 133 mg
- Soccer: 48 mg
- Magnesium: 13 mg
- Phosphorus: 210 mg
- Iron: 1.5 mg
- Vitamin B1: 0.09 mg
- Vitamin B2: 0.30 mg
- Vitamin B6: 0.12 mg
- Folic acid: 51 μg
- Vitamin A: 225 μg
- Vitamin B12: 2.5 μg
- Biotin: 20 μg
- Cholesterol: 358 mg
Beneficial properties of eggs
Eggs are a suitable food for everyone. Very nourishing and satiating, even in overweight or obese subjects, they contribute to metabolic regulations and to the maintenance of tissues, both from a functional and tonic point of view, thanks to the excellent presence of proteins and vitamins:
- In the yolk there are mainly the water-soluble B6 and B12, involved in the metabolism of nucleic acids, amino acids and fatty acids, in the prevention of cellular aging and in the stimulation of brain functions, the fat-soluble D, K, useful for bones, and the E, with strong antioxidant properties;
- In the egg white, however, vitamins B1 , B2 and B3 are concentrated mainly, involved in energy regulation.
Eggs are also friends of sight, given the presence of vitamin A, lutein and zeaxanthin, carotenoids with a protective action against the risk of degenerative eye diseases.
Eggs also have a form of protection towards the cardiovascular system and cleaning of blood vessels, given the presence of lecithin. It helps to esterify cholesterol through the synthesis of an enzyme, LCAT, and to remove excess from the bloodstream through the bile, contributing and preventing atherosclerotic diseases. There are therefore many properties of eggs, a food that is worth inserting regularly in the diet. But how many can you eat? And what are the best cooking methods?
How many eggs to eat and how to use them
In order to preserve its virtues, the method of cooking the eggs is fundamental. For example, the nutritional properties of a hard-boiled egg are almost comparable to those of a raw egg, but they will be better preserved if the cooking times do not exceed 8 minutes, starting from the beginning of the boiling of the water. This avoids the degradation of thermolabile vitamins (heat sensitive vitamins), the release of free radicals by peroxidation of fats and a lower digestibility of proteins.
Specifically, it is good to consider that it is mainly the egg white that must be well cooked as, as we have seen, it contains avidin, a substance that “sequester” biotin (prevents its absorption) and that is deactivated only with cooking. Furthermore, egg white is more prone to bacterial contamination, which is another reason why it should be well cooked.
As for the yolk, however, it can be eaten even more raw. In this way, not only is the content of thermolabile vitamins present inside it preserved, but its digestibility is also improved, as the yolk proteins are more digestible if subjected to short cooking. In general, therefore, we can say that the egg white must be well cooked while the yolk can also remain a little more raw.
And what about omelettes and scrambled eggs? For this type of preparations, due to the prolonged cooking and the high temperatures to which they are subjected, the nutritional properties of the eggs are partially compromised.
Healthy individuals have no particular motivation to drastically reduce their weekly egg consumption. Several studies have confirmed the absence of a direct correspondence between this food and the increase in blood cholesterol, attributable to a much more complex network of causes, such as excessive intake of sugars, refined carbohydrates, saturated fats, sedentary life, hypertension.
It is therefore possible to take even 4 eggs per week, remembering that for the purpose of a correct diet it is always preferable to vary the foods to be brought to the table as much as possible. If we want to increase the quantity, however, we can consume more egg whites, putting the yolks aside.
If we choose a plate of fresh egg pasta (about 100 grams of pasta), keep in mind that we will increase the intake of both proteins and fats, compared to an almost complete meal. Therefore, we could consider it as the replacement portion of an egg, among those that we will consume over the course of the week.
How to read the abbreviations on eggs
First of all it is good to consider that eggs can be of 3 categories: A, also called fresh eggs and intended for human consumption; B, second quality eggs, stored in the refrigerator and, finally, category C eggs, mainly intended for the food industry.
On the shell of each egg there is an alphanumeric code, made up of alternating numbers and letters that give specific indications on characteristics and origin. The first issue provides information about the type of farm:
- 0 = organic production
- 1 = outdoor farming
- 2 = on the ground
- 3 = in a cage
This is followed by two letters indicating the country of origin, three specific numbers of the municipality of breeding, the initials of the province to which they belong and, finally, three digits relating to the identification code of the laying farm.
How to properly store eggs
Once purchased, the eggs can be stored in the refrigerator at home, at a temperature of 4 ° C, for a maximum of 28 days. Refrigeration has the purpose of slowing down bacterial proliferation and avoiding food degradation. It is also possible to freeze egg products, after separation of egg white and yolk, while it is not possible to freeze a whole egg. Hard-boiled eggs, on the other hand, can be stored in the refrigerator for up to 6 or 7 days.
To understand if an egg is fresh there is a simple trick: immerse the egg in cold water and salt. If the egg rests on the bottom then the egg is fresh, if it floats, the egg is less fresh.
Contraindications of eggs
Properly balanced and associated with the right foods, eggs can be eaten without major problems, except for a few exceptions. In case of an established egg allergy, it is of course necessary to avoid its use altogether; in children, starting from 10 months only the hard-boiled yolk can be introduced, in small quantities at a time, crumbled into the baby food, and then switch to the egg white only after one year of age, since it is more at risk of causing allergic reactions being concentrated in proteins.
Subjects suffering from colitis must reduce consumption and prefer short and digestible cooking, such as poached or soft-boiled, while in the presence of gallstones the egg must be excluded because the cholecystokinin present in the yolk stimulates the contraction of the gallbladder, causing the formation of colic. In cases of gastritis, duodenitis and gastric ulcers, the eggs should not be totally eliminated, but limited, avoiding elaborate forms of cooking such as omelettes.
Eggs in brief:
- The calories of an egg are about 85. The value does not change with cooking;
- The fats, therefore also the cholesterol, are contained only in the yolk;
- Eggs contain proteins of very high biological value, but also vitamin B12, biotin and minerals;
- A hard-boiled egg, cooked for about 8 minutes, retains the same nutritional properties as raw egg;
- It is possible to consume 4 eggs per week or to increase the consumption of egg whites only;
- 100 gr of egg pasta replace an egg; During cooking, the egg white must be well cooked while the yolk can remain raw;
- A fresh egg immersed in water and salt does not float, a less fresh egg does;
- Fresh eggs can be kept in the fridge for about 28 days. They should not be frozen.