Maillard reaction

Maillard reactions—similar to but different from caramelization—occur among sugar and the amino acids, proteins, and peptides and are generally induced by heat. Sugar chemically reacts with proteins in the heat of the oven to contribute a golden brown exterior to baked products. The greater the sugar content of a mix, the deeper the end brown color. In addition, the crisp exterior that results helps the baked product retain its moisture for a longer period of time. These reactions also contribute to the wonderful, inviting aromas that emanate from baking breads, cakes, and cookies.