Baking is a widely known and loved activity. It has been practiced for centuries ever since humans discovered that certain ingredients have the capacities to interact with each other and heat forming completely new edible products – baked foods. Baking is, in fact, a chain of chemical reactions most cooks are familiar with, yet they are not aware of the reasons why the ingredients behave the way they do. This paper is focused on examining the main ingredients used in bakery from the point of view of Chemistry.
Flour is one of the main ingredients in baking. Most flours are mainly a composition of protein and starch.2 Wheat flour contains high level of gluten, which is a protein that turns into an elastic substance when mixed with water. This reaction causes the dough to puff up while baking and makes the final product fine, soft, light and airy.
Even though high level of gluten in flour provides a lot of benefits for the baked foods, there is one major disadvantage – many people cannot eat products that contain gluten due to a condition called Celiac disease.3 No wheat containing foods are allowed for these people. To provide such individuals with an opportunity to eat baked foods, wheat flour is replaced with almond flour. This kind of flour does not contain gluten, which makes it impossible for the almond flour dough to trap bubbles of air and rise during the process of baking as wheat flour dough does.3 Almond flour is hypoallergenic and this is its main quality.
Oat flour is another substitute to wheat flour. As well as almond flour, it is gluten free. This quality makes oat flour healthier for people with Celiac disease.1 The disadvantage of oat flour is that due to the lack of gluten the dough with it is not as elastic, and as a result the final foods may fall apart.1 This effect can be addressed if more binding and emulsifying elements such as water or eggs are added. Yet, one must be careful doing this as adding too many eggs makes baked foods heavier.
Yeast is composed of very small plants, which can grow and multiply by dividing into more plants.2 To be able to grow yeast requires warm, moist conditions with addition of sugar and starch because this is what yeast feeds on. The growth slows down when the ingredients are refrigerated. Yeast also produces alcohol. Another by-product of yeast is carbon dioxide; it forms bubbles that make the dough rise.2 The bubbles need to be spread evenly within the dough for better texture. Leaving such dough for too long will make it sour due to the influence of alcohol.2
Fat is the ingredient that traps the air bubbles within itself during intense mixing or beating. As a result, the substances become light and airy during baking as heat causes the bubbles of air to expand. Fat added between the layers of dough prevents them from sticking together, forming layered pastries. Fat limits the network of gluten, making the dough tender and easier to break. Fats contained in butter or lard are also used for their flavors. This way fat is responsible for such processes as creaming, shortening, layering and flavor.2
Sugar’s well known function is sweetening the products, but it also has a capacity to caramelize under heat, which provides browning to the pastries by means of adding an attractive looking crust on them. This is called Maillard reaction, during which sugar keton or aldehyde is turned into an unsaturated aldehyde or keton.2 Besides, high level of sugar improves the keeping feature of baked foods.
Sodium bicarbonate also known as baking soda is never used on its own. It is always mixed together with other ingredients, which contain acids. Sodium bicarbonate has a capacity to release carbon dioxide when it is heated. The overuse of baking soda makes baked foods taste unpleasantly bitter and can cause digestion issues. This happens when the incorrect pH level occurs.2
Baking powder is a mixture of sodium bicarbonate and a solid acidic substance. The addition of water makes both elements dissolve and react. Baking powder is preferred over pure baking soda because it is more balanced and its by-products are less alkaline so the taste of the final product is not ruined by too much sodium bicarbonate.2
Eggs contain a lot of lecithin, the protein that traps air bubbles when beaten providing lighter structure to the product. Eggs can also be used as a binding substance for keeping the ingredients together and producing a homogenous mass, in this case eggs are used to replace water.2 Besides, eggs are the source of nutritious fat and amino acids. Finally, eggs are often put on top of the baked foods for glazing because when heated they undergo Maillard reaction.
Salt is a necessary ingredient in the baked foods because it has the capacity to enhance the flavor of the final products and strengthen the fat and sugar mixtures that are initially soft.
In conclusion, baking is directly connected to Chemistry because it is based on a variety of chemical reactions between such elements as acids, salts, proteins and fats. Every valuable quality of baked goods is a result of some reaction, and knowing the correlation between the ingredients, their qualities and interactions makes a better cook, who is able to improve their products based on professional knowledge.
Bibliography
- Oomah BD. Baking and Related Properties of Wheat-Oat Composite Flours. Cereal Chem. 1983;60(3): 220-225.
- The Chemistry of Baking. Food-D-Baking n. d.;6: 1-8.
- Wallace J. The Effect of Almond Flour on Texture and Palatability of Chocolate Chip Cookies. Web.