Non-enzymatic browning is a natural process that produces a brown or “cooked” color in foods without the activity of enzymes, which are cell adjuvants—or, catalysts—for a specific biochemical reaction to take place in an organism. The two main forms of non-enzymatic browning are caramelization and the Maillard reaction.
Maillard reactions are essential in nearly all foods and may be partly or totally responsible for the distinctive flavor of baked goods, beer, chocolate, dairy, etc.. In many cases, such as in coffee, the overall food flavor is a combination of the Maillard reaction and caramelization.
Whereas Maillard reactions already occur at room temperature, caramelization, instead, only involves sugars, which have to be melted between 120‒150 °C.
Maillard reactions take place when a food possesses both free amino acids (coming from proteins) and reducing sugars (coming from either a monosaccharide or some 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.
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 reaction in food processing means influencing specific flavors to provide taste recall and profile consistency for a particular brand.