Maillard reaction
From WaiWiki
The heat-induced reaction of amino groups of amino acids, peptides, and proteins with carbonyl groups of reducing sugars such as glucose results in the concurrent formation of so-called Maillard browning products, such as heterocyclic amines (HCAs), acrylamides, Pent-4-en-1-amine, Styrene, Acetamide, Chloropropanols and Furan, which are all present in cooked foods.