Eggs are an essential part of many people’s diets, whether they’re part of a balanced breakfast or a key ingredient in a meal. Humans have been enjoying eggs from the very beginning of time and have domesticated animals for their egg laying for thousands of years. While humans may have eaten them raw before the advent of cooking, we didn’t do that for long. Since then, eggs have taken many forms on our plates, from over easy to omelets. But, they also play a key role in many recipes, aside from being a good source of protein. Knowing why we use eggs in cooking can help you adjust, and even create your own, recipes!
For the most part, eggs are used for three basic reasons: to create texture, add structure, and act as a bridge for other ingredients. When you dig deeper, these roles become much more interesting.
Tenderizes Baked Goods
Having a nice texture for your baked goods means balancing between firmness and softness. If a baked good is too soft, it’ll fall apart, but if it’s too firm, it’s like eating hardtack. Eggs play an important role in keeping baked goods tender by augmenting the chemistry of the dough.
Gluten proteins from the wheat provide structure and firmness to the bread. The longer the protein strands, the more firm and airy the final product is. The fats in egg yolks shorten the gluten strands, to make a more tender, softer baked good. Egg yolks have an emulsifying effect (more on that later) that help create smoother mixtures of batters and baked foods.
Tender cake is enjoyable to eat, but moistness is also important. Eggs help with achieving a moist cake in three key ways. First, eggs add moisture because they’re around 76 percent water. This directly adds liquid to the mixture. Similarly, fats can also add moisture. The other way is a bit more chemical, as the protein strands from eggs trap moisture within the dough.
A Leavening Agent
Eggs, especially egg whites, are used as leavening agents, which add an airy lightness to baked or cooked goods. The protein in eggs trap air bubbles that expand as the food is cooked. Since there’s so much water in the eggs, it turns to steam when heated. The air and steam trapped in the dough creates the leavening effect in baked goods.
Binds the Recipe Together
Eggs are rich in proteins. Like gluten from flour gives shape to a cake, egg proteins add structure to your recipes. Think of it this way: a brick wall without mortar would fall apart easily. The egg proteins act like a mortar for the other ingredients by binding different ingredients together. As the proteins solidify when cooked, they add structure to the food.
When you add a crust to fried chicken, for example, and you place it in an egg dip, the protein in the egg holds the flour and breading to the chicken. As it cooks, it firms up and keeps the breading in place to create the crispy outside of the chicken. Similarly, egg acts as a binding agent in burgers or meatballs, holding the strands of ground meat together to form a patty or ball. You could make a patty without egg or another binding agent, but it wouldn’t be nearly as cohesive.
Emulsification is the mixing together of two liquids that normally would not combine, like oil and water. If you’re making a sauce and the fat keeps separating from the rest of the sauce and settling on top, you need emulsification. Adding an egg is an excellent way to emulsify your sauces and dressings.
Both egg whites and yolks contain proteins that act as emulsifiers, albumin in egg whites and lectins in yolks. These proteins effectively act as middlemen between the ingredients that struggle to mix together, with one side of the protein combining with the one ingredient, usually an oil, and the other side combining with the other ingredient, usually water. This makes it easier for an emulsion to form since you can create one with enough temperature, mixing time, or force.
Finishing the Recipe
Finally, eggs can be used to add the final touches to a recipe in several ways. An egg wash, a mixture of egg white and water, can be used to create a shiny exterior on baked goods or hold other ingredients to the food. Furthermore, an egg wash can be used to seal puff pastry or other casings in recipes like a pie or Beef Wellington. A whole egg, both the whites and yolk, can promote the Maillard reaction on food, giving it a satisfying brown exterior.
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Whether it’s a breakfast egg scramble, egg salad at lunch, pasta for dinner, or a soufflé for dessert, eggs are useful in almost every meal. They create key characteristics of recipes and act as the glue that holds the other ingredients together. It’s safe to say that eggs play a key role in many kitchens.