For my final project, I decided to make blueberry muffins. I chose four components of the recipe to focus on: the use of different leavening agents and the difference between yeast breads and quick breads; why recipes often instruct you to mix wet and dry ingredients separately; starch gelatinization; and antioxidants and free radicals.
Muffins are technically a quick bread, which means that they are leavened using something other than yeast. While the leavening agents used vary by recipe, in general quick breads require at least one acidic agent and one basic agent. When the acidic and basic agents combine, they will release carbon dioxide. The carbon dioxide causes air pockets to form in the dough or batter, which will cause the bread to rise, similar to the way that it rises when you use yeast. As the name implies, quick breads rise much faster than yeast-based breads do. This is because when baking with traditional yeast, you need to wait for the chemical reaction that produces the carbon dioxide to occur before you bake your bread. When baking quick breads, however, the chemical reaction that causes the bread to rise actually occurs when the dough or batter comes into contact with a liquid and when it is actually being heated, which effectively removes one of the longest steps from the baking process. In my blueberry muffin recipe, I will be using baking powder as my leavening agent because it contains both acidic (baking soda) and basic (cream of tartar) components.
Oftentimes, baking recipes will instruct you to mix wet and dry ingredients separately and then combine them a little bit at a time. This is a crucial step that can dramatically improve the quality of your finished baked goods, for several reasons. Mixing the ingredients separately can make it easier for you to disperse the different ingredients throughout the mixture, which will result in a more consistent batter or dough. More importantly, however, mixing wet and dry ingredients separately will facilitate emulsion and prevent your batter or dough from becoming overworked. Most muffin recipes call for eggs, some type oil (often vegetable oil), and either milk or cream. Oil and milk do not mix with each other naturally, but the egg yolk acts as an emulsifier that helps bind the oil and milk together, which is necessary for a good muffin batter. Mixing the wet ingredients separately and then adding the dry ingredients incrementally will help create and preserve this emulsion. As we learned in the Breaking Bread lab, kneading bread dough can facilitate gluten formation, which makes the bread light and fluffy. However, when baking muffins, cakes, cookies, and other numerous other baked goods, excessive gluten formation can make the finished product very dense and crumbly. This is because gluten contributes to the batter’s elasticity, but overworking the batter can cause the gluten to become too elastic, which will prevent the batter from rising properly when cooked. Mixing the dry and wet ingredients separately reduces the likelihood that you will over mix the batter when you are trying to incorporate the ingredients into each other, which will prevent you from overworking the batter.
The muffin recipe I used, like many recipes for baked goods, called for a substantial amount of flour. Flour is an important ingredient because in addition to aiding in gluten formation, it also contributes to the structure of the muffins through the process of starch gelatinization. Starch is a major component in flour, and some varieties of flour can contain up to 75% starch. Starch gelatinization refers to the process by which starch molecules in the flour absorb water from the batter. This process begins to occur around 60°F, because starch is insoluble at lower temperatures. During starch gelatinization, bonds in the starch will break, which allows the hydrogen atoms in the starch to bond with water in the muffin batter. As the starch molecules absorb this water, the batter becomes firmer, which contributes to the baked muffin’s final structure.
Blueberries are often revered to as a “super food,” in part because they contain high levels of antioxidants that react with the free radicals in our bodies. The term “free radicals” refers atoms that contain valence (unpaired) electrons. Typically, an atom will contain electron pairs that stabilize each other and spin in opposite directions in the atom’s orbitals. However, when an atom loses a paired electron, the remaining unpaired electron will cause the atom to become highly reactive. The process of gaining and losing electrons occurs naturally in our bodies, but the resulting free radicals react with each other and with our cells, which can set off a chain reaction that results in even more reactions. The reaction with our cells can be detrimental to our health, and free radicals have been linked to cancer, autoimmune disorders, and a number of other diseases, as well as aging. Antioxidants are phytochemicals, vitamins, and enzymes that can prevent or stop the free radical reactions by donating free electrons to the free radicals so that their outer electrons are no longer unpaired. The pigments that give blueberries and other similarly colored berries their color contains anthocyanin, which is a powerful antioxidant with notable health benefits. This is why many of the foods that we typically associate with high levels of antioxidants are red, blue, or purple.
- 2 cups all-purpose flour
- 2 teaspoons baking powder
- ½ cup white sugar
- 1 stick unsalted butter, melted
- 1 egg
- ¾ cup milk
- 1 pint blueberries
- ¼ cup granulated brown sugar
- Preheat oven to 350 degrees F
- Mix flour, baking powder, and white sugar in a bowl
- Mix butter, egg, and milk in another bowl
- Gradually combine wet and dry ingredients and mix until just combined
- Stir blueberries into batter
- Pour batter into muffin tins; fill each cup approximately 2/3 full
- Sprinkle granulated sugar on top of the batter
- Bake for 25-30 minutes