The Maillard reaction is occurring for most of cooking: such as caramel, or roasting.
What is Maillard reaction?
The Maillard reaction was first discovered by Louis Camille Maillard and the reaction between carbohydrates (sugar) and proteins, and is responsible for changes in color, flavor and nutritive in food.
The Maillard reaction occurs in three main steps:
The ketosamine products then either dehydrates into reductones and dehydro reductones, which are caramel, or products short chain hydrolytic fission products such as diacetyl, acetol or pyruvaldehyde which then undergo the Strecker degradation.