The Maillard reaction is the name given to a reaction between sugars and amino acids and proteins when subjected to heat. In cooking, it causes browning of food and creates complex flavors.
The Maillard reaction is named for its discoverer, Louis-Camille Maillard, who first described it in 1912. It occurs at temperatures ranging from 122 to 329 degrees Fahrenheit and results in complex mixtures of molecules which vary by the food being browned. Foods that derive some of their flavor from the Maillard reaction include seared, grilled or roasted meats; baked goods; the coatings of deep-fried foods; malted barley; and maple syrup.