Maillard reactions—also known as non-enzymatic browning—are essential in nearly all foods and are (partly) responsible for the flavor of baked goods, beer, chocolate, etc.. In many cases, such as in coffee, the total flavor is a combination of Maillard reactions and caramelization.
Maillard reactions take place when a food possesses both free amino acids (coming from proteins) and reducing sugars (coming from either a monosaccharide or certain disaccharides, oligosaccharides, and polysaccharides). Combined, these agents generate a vast array of complex compounds, depending on pH (acidity), activity water (the ability of the available water molecules to bind other substances), presence or absence of oxygen, time, and temperature.
Whereas Maillard reactions already occur at room temperature, caramelization, instead, only concerns sugars, which have to be melted between 120 – 150 °C.
The Maillard reaction is named after the French scientist Louis Camille Maillard, who studied the reactions of amino acids and carbohydrates in 1912.
Understanding and controlling the Maillard reactions in food processing means influencing specific flavors to provide taste recall and profile consistency for a particular brand.