This is the science behind the classic banana bread recipe!
Banana bread uses many scientific principles. One of them is that it uses both baking soda and baking powder. The acidic counterpart to baking soda is the lemon juice that is added to the smashed bananas, because although bananas are technically acidic fruits, they are not acidic enough for the reaction. The baking soda acts as a leavening agent to lift the bread, but if it was just used by itself, it would alter the taste of the bread, and also change the color to be much darker. The lemon juice is used to counteract the basicness of the baking soda, and to slow the Maillard browning reaction. The recipe also calls for buttermilk, which assists in increasing the acidity to balance the baking soda. Both baking soda and powder are used when buttermilk is an ingredient in Banana bread because the soda isn’t enough to lift the bread.
The recipe uses flour and eggs as the main bases that react, and making sure to use the exact amount that the recipe calls for is crucial because not doing so could affect the texture of the bread. These ingredients are the core of the reaction other than the leavening agents, and changing these can alter the texture grittiness, the dryness/wetness, and the holding together of the bread itself. The recipe also stresses not to overmix the batter. if you overmix the wet and dry ingredients, the flour will start to over-develop and create more gluten, which would result in a tough, dense and rubbery bread.
The Bananas are also supposed to be overripe, which increases the amount of Maillard browning, and fructose present in the bananas. The ethylene gas that is released once bananas have been picked causes a decrease in acid, the breakdown of chlorophyll, and the conversion of starch into sugar. This conversion makes the bananas sweeter, which when added to the banana bread, makes the bread sweeter. The decrease in acid makes it a more basic environment, and the sugar present makes the Maillard browning reactions occur.
When it comes to the science of the process, the butter is creamed first to incorporate air into the butter, which helps the batter become fluffier and not as dense. The dry ingredients aren’t added to the wet ingredients until the very end because there are 2 types of leavening agents in the dry ingredients, and we don’t want them to start reacting until the bread is in the oven. The reason the bread is baked at a lower temperature for a longer time is because you don’t want the outside to become to crispy and burnt while the inside is undercooked. The batter for banana bread is fairly dense, so you want enough time for the heat to travel through and cook the bread all the way through without burning the outside to a crisp.