What kind of change does a cake that is cooking undergo as it bakes? I would think it was a chemical and physical change. Am I correct?
Yes, you are correct! When a cake is cooking, it undergoes both chemical and physical changes. Let me explain each of these changes in more detail:
1. Chemical Change: During the baking process, various chemical reactions occur within the cake batter. One of the key reactions is the combination of ingredients such as flour, sugar, eggs, and leavening agents (such as baking powder or baking soda) with heat. This causes the ingredients to undergo chemical reactions, resulting in the transformation of the batter into a completely different substance – a cake. This is often referred to as the "baking reaction."
2. Physical Change: In addition to the chemical changes, numerous physical changes occur during the baking process. These changes involve alterations in the cake's physical structure, appearance, and texture. Here are some examples of physical changes that take place while a cake bakes:
- Evaporation: As the cake batter heats up, some of the liquid ingredients (such as water or milk) start evaporating. This loss of moisture causes the cake to become less liquid and more solid.
- Expansion: The heat applied to the cake batter causes air bubbles trapped within the batter to expand, leading to the rising or leavening of the cake.
- Browning: During baking, the outer surface of the cake goes through a process called the Maillard reaction. This reaction causes a chemical change in the proteins and sugars present on the cake's surface, resulting in a golden-brown color and the development of desirable flavors and aromas.
- Setting: The heat from the oven causes the proteins in the batter to denature and coagulate, which helps the cake solidify and hold its structure when cooled.
So, in summary, a cake cooking undergoes both chemical changes (such as the transformation of ingredients into a cake) and physical changes (such as evaporation, expansion, browning, and setting).