Coffee aroma and its 800 molecules

There are five criteria to taste and evaluate coffee : strength, acidity, aroma, sweetness and bitterness. Which process give these different tastes to coffee? Of course, there is coffee-roasting but basically it’s closely related to genes.

Roasting

The coffee-roasting, a heating process up to 200°C, transforms odourless molecules, or chemical precursors present in coffee beans, into odour molecules. The coffee aroma is composed of 800 molecules. Some factors such as temperature or lenght of roast will determine if the coffee will be bitter, acidic… The quantity of molecules present in beans will also influence this aroma and depend on the way the genes are expressed. A gene is a segment of DNA. It’s a code. The decoding of the information contained in a gene is called gene expression.

It depends on the expression of genes

The biosynthesis of precursors such as polysaccharids, lipids (particularly triglycerides), saccharose and chlorogenics acids (phenolic compounds), depend on the expression of 137 genes of Arabica coffee. This kind of coffee constitutes 75% of the world market. That’s the reason why it’s the aim of many research projects.The studies of the of IRD and Cirad (French research center) researchers have permitted the identification of genes involved in the formation of the precursors.

However, they should evaluate if the environment has an effect on the expression of these genes. A lot of work for the future!

Reference :

Metabolic pathways in tropical dicotyledonous albuminous seeds: Coffea arabica as a case study