What effect does lemon juice have on a raw egg?

When lemon juice is added to a raw egg, the acidic nature of the juice causes the proteins in the egg white to coagulate and the yolk to become firm. This is because the acid causes the protein molecules to unfold and form new bonds with each other, creating a solid structure. The process is similar to what happens when an egg is cooked in heat, but the lemon juice provides an acidic environment instead of heat. This reaction is also known as protein denaturation.

The chemical process that takes place when lemon juice is added to a raw egg can be explained as follows:

- The lemon juice contains citric acid, which is a weak organic acid.

- The acid molecules dissociate in water, releasing hydrogen ions (H+) and citrate ions (C6H5O7-).

- The hydrogen ions react with the amino acids in the egg white proteins, causing them to become positively charged.

- The positively charged amino acids then repel each other, causing the protein molecules to unfold and become disorganized.

- As the protein molecules unfold, they expose their hydrophobic (water-hating) side chains to the water.

- The hydrophobic side chains of the protein molecules interact with each other, forming new bonds and creating a solid, coagulated structure.

This process of protein denaturation is also responsible for changes in the texture, appearance, and flavor of eggs when they are cooked. For example, when an egg is fried, the heat causes the proteins in the egg white to coagulate and the yolk to become firm, while the flavor of the egg changes due to chemical reactions between the proteins and sugars.