Caramelization is the browning of sugar, a process used extensively in cooking for the resulting sweet nutty flavor and brown color. The brown colors are produced by three groups of polymers: caramelans (C24H36O18), caramelens (C36H50O25), and caramelins (C125H188O80). As the process occurs, volatile chemicals such as diacetyl are released, producing the characteristic caramel flavor.
Like the Maillard Reaction, caramelization is a type of non-enzymatic browning. However, unlike the Maillard reaction, caramelization is pyrolytic, as opposed to reaction with amino acids.
While increasing the complexity of flavors, caramelization reduces the fermentability of sugars.