Browning reaction can be a sign of product spoilage but it is useful in many food preparations. Popular examples are: toasted bread and biscuits, beer, cassava cakes, condensed milk, caramel, roasted meat and bread.
The Maillard reaction in foods is a chemical reaction between an amino acid and a reducing sugar, usually requiring heat. It is vitally important in the preparation or presentation of many types of food, and, like caramelization, is a form of non-enzymatic browning.
In the process, hundreds of different flavor compounds are created. These compounds, in turn, break down to form yet more new flavor compounds, and so on. Each type of food has a very distinctive set of flavor compounds that are formed during the Maillard reaction. It is these same compounds that flavor scientists have used over the years to create artificial flavors.
Toasted bread and Biscuits