Why does egg wash make baked goods shiny?

* Proteins: Egg whites contain proteins that denature (change their structure) when heated. This denaturation creates a thin, transparent film on the surface of the baked good.

* Moisture: The egg wash adds moisture to the surface, which helps the crust to brown and develop a glossy finish.

* Fat: Egg yolks contain fat, which contributes to the shine and helps create a richer, more flavorful crust.

Here's a more detailed breakdown:

1. Before baking: When you brush the egg wash onto the dough or batter, the proteins in the egg white are in their native state.

2. During baking: As the oven heats up, the proteins in the egg white denature and solidify, forming a thin film on the surface. This film traps some of the moisture within the baked good, contributing to a moister and more flavorful crust.

3. After baking: The film created by the egg wash dries and becomes transparent, leaving a glossy finish on the baked good. The fat in the egg yolk contributes to the shine, creating a more golden and vibrant hue.

Other factors that contribute to shine:

* Sugar: Sugar in the dough or batter also contributes to browning and glossiness.

* Milk solids: If you use milk in your recipe, the milk solids will also contribute to the shine.

Overall, egg wash is a simple and effective way to add shine, texture, and a beautiful golden brown color to your baked goods.