Most people know that eggs are very healthy and are a great source of high-quality protein. Getting enough protein is very important for building bones and muscles, as well as maintaining good overall health. But what type does this food contain?
Not everyone looks at the type of protein, carbohydrate, or fat they eat with each meal. However, this can be interesting to create strategic eating plans. In the case of the egg, we will analyze the amount and types found in the whites and yolks.
How much protein does an egg contain?
The average egg contains around 6 to 7 grams of protein. However, the content of this macronutrient depends on the size of the egg. So, approximately, this is the amount that the different sizes contribute:
- Small (38 grams): 4,9 grams of protein
- Medium (44 grams): 5,7 grams of protein
- Large (50 grams): 6,5 grams of protein
- Extra large (56 grams): 7,3 grams of protein
- Giant (63 grams): 8,2 grams of protein
To put these numbers into perspective, a typical sedentary man needs about 56 grams of protein per day, while a sedentary woman needs about 46 grams. In the case of athletes, the amount should be greater to meet the physical demands of the muscles.
Yolk and white protein content
Now let's look at the protein content of the different parts of the egg. People often think that protein is only found in egg whites, since they are made up of little more than protein. Egg yolks are known to be where almost all the nutrients and fats are found.
However, in addition to these nutrients, the yolk also contains up to approximately half of the egg's protein content. In a large egg containing around 7 grams of protein, 3 grams will come from the yolk and 4 grams from the white . Therefore, eating the whole egg, not just the white, is the best way to obtain the most protein and nutrients.
Protein types
Egg proteins, which are distributed in both the yolk and the white (albumin), are nutritionally complete proteins containing all the essential amino acids. Egg protein has a "chemical score" (the level of essential amino acids in a protein food divided by the level found in an "ideal" protein food) of 100, a "biological value" (a measure of how efficiently dietary protein is converted into body protein) of 94, and the highest "protein efficiency ratio" of any dietary protein.
The main proteins found in egg yolk include low-density lipoprotein (LDL), which makes up 65%, high-density lipoprotein (HDL), phosvitin , and livetin. These proteins exist in a homogeneously emulsified fluid. Egg white is composed of about 40 different types of proteins. Ovalbumin is the main protein (54%), along with ovotransferrin (12%) (a type of protein whose main characteristic is its ability to bind iron, providing antimicrobial properties) and ovomucoid (11%). Other proteins of interest include flavoprotein, which binds to riboflavin; avidin, which can bind and inactivate biotin; and lysozyme, which has a lytic effect against bacteria. Ovomucin, another type of glycoprotein, is also present, representing less than 2% of egg white protein, and is responsible for providing the gelatinous texture.
Egg protein contains substantial amounts of essential and non-essential amino acids. Although a large egg provides only 3% of the energy of a 2000 kcal diet, it provides 11% of protein needs. The essential amino acids in an egg contribute between 12% and 31% of the recommended daily allowance.
Does cooking affect protein quality?
The high-quality protein abundant in eggs contains all nine essential amino acids in the correct proportions. However, the amount of that protein the body can actually use seems to depend on how they are prepared. Eating raw eggs appears to provide the least amount of protein.
One study looked at how much protein was absorbed from cooked eggs compared to raw eggs. It found that participants absorbed 90% of the protein from cooked eggs, compared to just 50% of the protein from raw eggs. Another study gave healthy people a meal containing cooked or raw egg protein. It found that 94% of the protein in the cooked egg was absorbed, compared to only 74% of the protein in the raw egg.
This means that cooking eggs helps make the protein more digestible and more readily available to the body. Furthermore, eating raw eggs carries a risk of bacterial contamination and food poisoning.
What do egg supplements contain?
There are mainly two types of egg supplementation: albumen and whole egg powder.
Egg white supplement is obtained by separating the egg white from the yolk. The white is then subjected to a dehydration and spray-drying process to obtain a fine powder. It is commonly used to mix with water to make shakes or smoothies. It is also used to create high-protein recipes. It is a food that is pure protein, with no fat, carbohydrates, or cholesterol. In fact, 30 grams of egg white supplement is equivalent to 7 egg whites and 26 grams of high-biological-value protein.
On the other hand, the whole egg powder is also often sold as a supplement. This format is used in confectionery as an emulsifier, improving the miscibility between lipid and other aqueous phases. Thanks to this, the mixtures of the recipes manage to be more homogeneous. In addition, thanks to the characteristics and proteins of the albumen, the egg coagulates when subjected to heat, becoming the key ingredient in any dessert.
It can also be used to cook savory recipes. Remember that the egg is an excellent source of protein, phospholipids, vitamins and minerals. In addition, 51% of its composition is protein. The rest of the nutrients are the same as those of a normal whole egg. In this case there are fats and carbohydrates.