What Does Adding Egg to Pastry Do? – A Comprehensive Guide

Eggs are among the most essential ingredients used in pastry baking. They are present in most pastry products, and some of them cannot be made without eggs. In this blog post, we’ll explore the composition of eggs and their role in baked goods.

Eggs have a diverse impact on pastries. They:

1. Increase moisture content.
2. Increase the cake's sponginess by trapping air with a thin film.
3. Enrich products they are used in.
4. Serve as emulsifiers, especially in sponge cakes. 
5. Play a significant role in binding the ingredients in pastry.
6. Enhance the flavor and color of cakes.

The Significance of Eggs in Baking

Eggs are one of the most crucial ingredients in pastry making. When incorporated into the dough, they enhance the nutritional value and impart a golden hue to the pastry’s structure. The lecithin found in egg yolks acts as an emulsifying agent, facilitating the even distribution of fat in the dough.

Whipped egg whites serve as a physical leavening agent, contributing to the lightness of beaten batters. When brushed onto the surface of the pastry, egg wash transforms into a shiny glaze during baking. Additionally, eggs are an essential ingredient in custards and creams.

Eggs are essential components of many baked goods. They provide a light and airy quality to pastries while ensuring stability and uniformity. Eggs, except for hard-boiled ones, are among the most easily digestible substances.

We use whole eggs, pasteurized egg liquids, and egg powder in baking. In pastry making, we typically use chicken eggs, although it’s possible to use eggs from other birds. However, it’s important to note that duck eggs should be avoided as they can easily lead to food poisoning.

The Composition of Eggs

Eggs are at their best when they are absolutely fresh, typically in the size range of 50-55 grams. An egg’s composition includes approximately 11% shell, about 58% egg white, and roughly 31% yolk.

A complete egg contains approximately 75% water, about 13% protein, and roughly 12% fat. Egg white has a water content ranging from 86% to 91%, with a dry matter content of 8-12%, consisting primarily of proteins, a small amount of fat, and some carbohydrates. The water content of the egg yolk is 45-50%, and the protein content ranges from 14-17%. The egg yolk’s fat content is 30-34%, primarily composed of lecithin and cholesterol.

The energy content of an egg is primarily derived from its fat and protein content. The yolk’s energy value is predominantly due to fat, while the energy value of the egg white solely comes from proteins, as it contains minimal fat. The egg white is primarily composed of proteins dissolved in water.

As eggshells are porous, various biochemical and physical changes occur inside them during storage, which can reduce quality or lead to spoilage. Eggs should be stored in the refrigerator at temperatures ranging from 41 to 64°F (5 to 18°C), for up to 30 days.

The Role of Eggs in Pastry Making

1. Increased Moisture Content

Eggs contain a significant amount of water, with roughly 75% of their weight consisting of water. This water content in eggs is a source of moisture in baking, and it contributes to the hydration of the dry ingredients, such as flour and sugar. Fresh eggs, in particular, are considered wet ingredients in baking due to their high moisture content.

As the pastry bakes, the water content in the eggs turns into steam, contributing to a moist interior. This steam helps maintain a moist environment within the pastry, preventing it from drying out during baking.

Eggs also contribute to the freshness of pastries. Their moisture content helps keep the pastry from becoming stale too quickly. Moisture from eggs helps maintain the pastry’s quality for a more extended period by keeping baked goods soft, moist, and fresh, preventing them from becoming dry and crumbly.

2. Physical Leavening

Egg white is highly valuable in the confectionery industry primarily because of its excellent whipping properties, which are crucial for creating the right volume in light pastries such as sponge cakes and soufflés.

With the addition of the recommended amount of sugar, an egg can effectively aerate an equal weight of flour as its own weight. However, if you’re incorporating more flour into a whipped pastry than the weight of the egg, you may need to consider other leavening agents like baking powder.

The leavening effect of eggs comes from the air they trap. Egg white forms membranes that enclose a relatively large amount of air without breaking, thereby enhancing the light and airy texture of the dough.

During beating, egg white captures air and expands in volume, making it suitable for lightening batters and creams. It also can bind a significant amount of water and coagulate upon exposure to heat, providing structure and stability to baked goods.

As pastries containing eggs bake, the water in the eggs evaporates and turns into steam. This steam also helps with the rise and tenderness of pastries.

3. Enriched Texture and Nutrition

The egg yolk, in particular, contains a significant amount of fat. This fat not only adds flavor but also contributes to the richness and tenderness of baked products.

Fat helps inhibit the formation of gluten, a protein responsible for the elasticity and toughness of some baked goods. By reducing gluten development, eggs can result in a more tender crumb in pastries like cakes and cookies.

During the cooking of custards, creams, and fillings, the egg yolk binds water and acts as an excellent thickening agent. In some pastry recipes eggs are used as a binding agent to hold the ingredients together, creating a cohesive mixture. In cheesecakes, eggs play a critical role in achieving a creamy and dense filling.

Additionally, egg yolks contain vitamins A, B1, B2, and D, as well as iron, calcium, potassium, and phosphorus.

While we’re on the subject of eggs in baked goods, you may wish to read my article on whether bread dough needs eggs or not.

4. Emulsification

Among the compounds found in the egg yolk, lecithin is essential. Lecithin is a phosphoric acid compound bound to fat and is valuable for its emulsifying properties. This property allows them to blend and stabilize ingredients that would typically separate, such as water and fat. In doing so, eggs create a smoother and more uniform texture in the final product.

5. Binding ingredients

Egg whites are rich in a protein called albumin, which is primarily responsible for binding. Albumin consists of proteins that have a unique ability to denature (unfold) and coagulate (form a stable structure) when exposed to heat. This denaturation and coagulation process occurs during baking, helping to create a network that holds the pastry ingredients together.

This coagulated protein network is what gives pastries their structure and stability. It prevents the pastry from falling apart and maintains its shape during baking.

6. Enhanced Flavor and Color

In custard-based pastries like crème brûlée or flan, egg yolks are the most important ingredient. They provide the distinctive creamy and custardy flavor that defines these desserts, making them smooth and flavorful.

The egg yolk acts as a natural coloring agent, as it contains pigments that give baked goods their yellow color. Eggs, when used as an egg wash, can provide a glossy and golden-brown finish to the surface of baked items.

Furthermore, egg white’s protein content contributes to the browning and the formation of a crust in baked goods. This not only improves the appearance but also adds an appealing aroma and flavor due to the Maillard reaction.

Eggwash can also be used to help toppings, like seeds or sugar, adhere to the surface of baked goods.

Final Thoughts

In conclusion, eggs are a fundamental ingredient in pastry baking, contributing to the structure, moisture, flavor, texture, color, and leavening of a wide variety of baked goods.

Eggs are a staple in baking, making pastries better in various ways. Their versatility makes them indispensable in various types of pastries, from cakes to pies.