Browning is a process of gradual change in the color of food products to brown or dark brown over time, which can affect the food quality in either a positive or negative manner.
Numerous reactions lead to browning in foods. Some of these may generate flavors and/or alter the nutritional properties of foods.
Maillard reaction is a browning caused by sugars and amino acids reacting with each other. This creates many of the desirable flavors in the coffee. Heat speeds up the reaction.
The desirable fragrance of coffee beverages develops during roasting procedures. Typical roasting temperatures range from 180 to 250∘ C, and roasting time varies between 2 and 25 min depending on the process employed.
After 3-4 minutes of roasting, the coffee has sufficiently dried to allow other enzymatic and non-enzymatic changes to begin. This is observable as the bean changes from green to yellow to brown. The that sugars are breaking down, amino acids are realigning, and the chemistry of the bean is changing. At this point, it tends to have a grassy and bready aroma.
Non-enzymatic browning reaction in coffee
