Question answered by Dr. Catherine Riddle, Radiochemist, Idaho National Laboratory
Baking causes a chemical change in your ingredients from raw batter to cooked cakes, breads, cookies, or biscuits. Since there are multiple reactions depending on what you are baking, let’s look specifically at the chemistry that goes into baking a cake step by step. Last week we learned about the chemistry of boiling water, butter, eggs, flour, sugar and baking powder. This week we will learn about the Maillard reaction and heat. (You can check out Part 1 of baking chemistry at www.idahoaskascientist.com.)
The Maillard Reaction. The Maillard reaction works its magic during baking by breaking down sugars and amino acids in the batter which are responsible for flavor formation which occurs between 140oC – 165oC (284oF – 329oF). In 1912 French biochemist Louis Camille Maillard (pronounced “my-yar”), studied reactions between amino acids and sugars in food at elevated temperatures. This reaction not only changes the color of your cake it also affects its texture, flavor, and is the reason it turns golden brown. For more information on the Maillard reaction you can visit https://cen.acs.org/articles/90/i40/Maillard-Reaction-Turns-100.html.
Heat. Heat is very important in baking and it produces two types of chemical reactions. The first is “exothermic,” a reaction that produces heat; the second is “endothermic,” a reaction that absorbs heat. Heat helps the eggs and the baking powder (specifically the sodium bicarbonate) to do their job in our confection. As our cake bakes, it produces an endothermic chemical reaction that changes batter into a fluffy, delicious dessert!Finally, after all the physical and chemical reactions, the breaking of bonds, production of flavors, and yes, all your hard work too, your culinary chemistry achievement is now ready to enjoy!
Have you ever smelled bacon sizzling in the frying pan? That amazing aroma is due to the Maillard Reaction. The Maillard reaction is many small, simultaneous chemical reactions that occur when proteins and sugars in and on your food are transformed by heat, producing new flavors, aromas, and colors. The Maillard reaction is sometimes called the browning reaction. You can see the results of this reaction in many of our cooked foods like:
- Caramel made from milk and sugar
- Baked goods like cookies and cakes
- Roasted meats and vegetables
- Dried fruit like raisins
- Fried eggs and potatoes
- Self-tanning products (not food, but super-cool!)
Maillard reactions happen best when two factors are used: dryness and high heat. The reactions can happen quickly like when we bake (or toast) bread or slowly like when grapes are dried into raisins.
You will need: 2 slices of bread, toaster
- Toast one of the slices of bread.
- Compare the toast to the untoasted bread. Can you see the difference? Do they taste differently? Do they smell the same?
For further research you will need: 2 pieces of beef, fish or chicken, plastic wrap, wire rack, skillet, stove
- Make sure your 2 pieces of meat are similar in size.
- Wash your hands.
- Wrap one piece of raw meat tightly in plastic wrap.
- Place the other piece of raw meat on a wire rack over a plate to dry out.
- Wash your hands thoroughly again.
- Place both pieces of meat in the refrigerator for an hour.
- Unwrap the meat and, with an adult helper, sear each piece of meat separately in the skillet.
Did you notice a difference in the pieces of cooked meat? Do they look the same? Do they taste the same?
Surface moisture takes time to cook off, so wetter meat is often done before the Maillard reaction can fully take effect. But if you dry the meat before you cook, the Maillard reaction happens and all those flavor compounds permeate the meat.