What happens to flour when heated?

When flour is heated, several changes occur due to the application of heat:

1. Protein Coagulation: Flour contains gluten proteins, which form a network when mixed with water. When heated, these proteins coagulate or solidify. This process is similar to the coagulation of egg white when boiled. The coagulation of gluten proteins gives structure and elasticity to baked goods.

2. Starch Gelatinization: Starch is the main carbohydrate in flour. As flour is heated in the presence of water, the starch granules absorb water and swell, causing the mixture to thicken. This process is called gelatinization. The gelatinized starch forms a gel, trapping water and contributing to the texture of baked goods.

3. Maillard Reaction: When flour is heated, the reducing sugars (such as glucose) present in the flour react with amino acids to produce a range of compounds through a series of complex chemical reactions known as the Maillard reaction. This reaction is responsible for the development of brown colors, flavors, and aromas characteristic of baked goods. Examples include the golden crust of bread or the browning of cookies.

4. Evaporation of Moisture: As flour-based products are heated, moisture evaporates. The evaporation of water results in the removal of steam and contributes to the formation of a crust. In baked goods like bread or cakes, the process of evaporation leads to the characteristic rise and expansion of the product.

5. Browning Reactions: The high temperatures during baking or heating cause the caramelization of sugars and the browning of proteins, contributing further to the color and flavor development of flour-based products.

It's important to note that the specific changes that occur when flour is heated can vary depending on factors such as the type of flour, the temperature, the duration of heating, and the presence of other ingredients.