Caramelization

Caramelization is the browning of sugar that occurs when it is heated, breaking the sugar molecules down and recombining them into hundreds of new aromatic compounds, including diacetyl, which produces the flavor recognized as buttery, as well as the characteristic brown color. Distinct from the Maillard reaction, which requires both sugars and proteins, caramelization is used deliberately to make caramel candy, to brown onions slowly into a sweet, deep-flavored condiment, and to give roasted vegetables and baked goods their surface color and flavor. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/