The blends are controlled for flavor, aroma, color and strength or body of the beverage from the roasted bean.
It has been established, primarily from gas chromatography evidence, that there are nearly 1000 different more or less volatile compounds present in roasted coffee.
Most results from the thermal decomposition of carbohydrates and phenols, especially chlorogenic acids that are present at significant concentrations in green beans during roasting.
Some compounds are located in the carbohydrate matrix of the roasted bean whereas others are located in the coffee oil distributed within the bean.
Heterocyclic aroma chemicals, which are major constituents of a brewed coffee extract possessed considerable antioxidants activities.
The flavor and aroma of coffee are best when it is freshly roasted. Many of the aromatic components of roasted coffee, and particularly of coffee oil itself, are extremely susceptible to deterioration by the action of moisture and oxygen.
The staleness of coffee exposed to air is due to the oxidative changes that take place with certain coffee constituents.
The major factor affecting coffee quality is the length of storage, as volatile aroma compounds are lost, especially from ground coffee, with methanethiol and 2,3-pnentanedione being used as indicators of coffee freshness, because they are rapidly lost on storage, especially the 2,3-pentanedione.
Coffee aroma chemicals
