What is an Egg Yolk?
The egg yolk is the yellow part of the egg that is surrounded by white or clear material. When an egg is fertilized, the developing chick uses the egg yolk as a food source, and it’s an excellent one because of its nutritional content. This superior nutrition has long been recognized by humans as a primary reason to eat eggs. However in modern times, the higher cholesterol and fat content of egg yolks may make some people avoid them and eat the egg white only.
The nutritional components of the egg yolk are striking. In chicken eggs, egg yolks contain half the egg’s protein amounts, and each yolk has about 60 calories. They offer excellent levels of vitamins A, D, and E. The downside of yolks is their cholesterol content, which is about 200 mg. Since it’s recommended that people get no more than 300 mg. of cholesterol a day, two eggs easily exceeds cholesterol limits. For people who have high cholesterol levels and must lower intake, eating egg yolks is usually not recommended.
Many ignore these guidelines and use eggs to make a variety of foods. These include simply cooking the eggs in different ways. Sunny side up eggs take advantage of the look of the egg yolk because it stays intact as the egg cooks. Hard-boiling eggs also results in a solid yolk in the center of the egg. Other times, people mix the yolk and white of the egg to create things like scrambled eggs, omelets, quiches and frittatas.
Eggs are frequently used in baking and the egg yolk is very helpful in this respect. It acts as an emulsifier, binding ingredients together. Sometimes recipes require only egg yolks.
In many cake recipes, separating yolks from egg whites is required. Recipes for white cakes usually use egg whites only, which can leave a lot of leftover yolks. Cooks may choose to use these in cakes that are “yellow” cakes, and yolks can also be used in custard or things like hollandaise sauce.
Humans haven’t just viewed the egg yolk as a source of food. Sometimes yolks may be used on Petri dishes to help identify certain forms of bacteria. Tempera paints were traditionally made by adding dyes to egg yolks. In some cultures, women have used egg yolks as a facemask to treat acne or various other skin disorders. Advice columnists like Dear Abby occasionally recommended the treatment to her readers.
Written by Tricia Ellis-Christensen
