Eggs and Protein
A combination of amino acids, some of which are called essential because the human body needs them but can't synthesize them. The human diet must regularly supply protein which contains all of the essential amino acids. The egg boasts them all: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptoOphan and valine. They are present in a pattern that matches very closely the pattern the body need, so the egg is often the measuring stick by which other protein foods are measured.
In addition to the 9 essential amino acids, there are 9 other amino acids in an egg. Altogether, each Large egg provides a total of 6.25 grams of high-quality, complete protein. For this reason, the egg is classified with meat in the food categories. One egg = 1 ounce of lean meat, fish or poultry. A Large egg provides 10 to 13% of the Daily Reference Value for protein and varying amounts of many other nutrients.
Egg Yolk Nutritional Information
The yolk or yellow portion makes up about 33% of the liquid weight of the egg. It contains all of the fat in the egg and a little less than half of the protein.
With the exception of riboflavin and niacin, the yolk contains a higher proportion of the egg's vitamins than the white. All of the egg's vitamins A, D and E are in the yolk. Egg yolks are one of the few foods naturally containing vitamin D.
The yolk also contains more phosphorus, manganese, iron, iodine, copper, and calcium than the white, and it contains all of the zinc. The yolk of a Large egg contains about 59 calories.
It is the yolk which is responsible for the egg's emulsifying properties.
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