M—Cheftionary

 Maillard Reaction

A chemical reaction between amino acids and reducing sugars that occurs when food is exposed to dry heat above approximately 285°F (140°C).

This reaction produces hundreds of flavor and aroma compounds responsible for the brown color and savory complexity found in seared meat, toasted bread, roasted vegetables, and coffee. 

The Maillard Reaction cannot occur in the presence of surface moisture, because water limits temperature to the boiling point (212°F).