Coffee chemistry| Analysis and Bioconversion

Coffee plant and brewing

Coffee is a popular plant that grows well in tropical countries. The popularity of coffee is due to it beans . This is because, the beans are used all around the world. Different countries have brands of coffee as commercial products but the processing is not exactly the same. Therefore , the appearance and taste are not exactly the same.

However, the beans which usually appear dark and brown. The processing require drying or roasting with heat from natural sunlight or artificial heating. In addition to this , the beans can be grounded into different sizes and sold in the market .

Finally , it is brewed into beverages in raw or processed form around the world. The brewing of coffee involves boiling the beans in hot water and then separating the beans from the water. The water is served as a beverage and people drink it with or without sugar and milk.

Chemical composition 

Most people are only interested in the consumption and taste of the beverage . However, they have little knowledge of the constituents besides caffeine. In addition to caffeine , the other predominant organic compounds are trigonelline and chlorogenic acids.

Caffeine, trigonelline and chlorogenic acids are waste products from the coffee plant. These are also known as secondary metabolites and are stored in the coffee beans. The chemical structure and function of these compounds depends on the structure of the precursors which are the compounds from which there are made. 

For instance , caffeine is made by bioconversion from Xanthosine which is a made from xanthine and ribose sugar. This is made possible by the help of a specific enzyme that is called synthase. Trigonelline is made from nicotinamide adenine dinucleotide (NAD)  and this involves nicotinic acid compound  byproduct. In addition to the above , caffeine and trigonelline are alkaloids but have different structures. Caffeine has a purine structure but trigonelline has a pyrimidine structure. 

Lastly, chlorogenic acids are mainly produced from bioconversion  of core phenylpropanoid molecules. 

Ref: Coffee Plant Biochemistry by Ashihara, Fujimura and Crozier

Biochemistry in the body

Apart from the above , these three compounds interact with body. This occur as soon as coffee is consumed and digested. As a result, this starts the  effects that is normally observed from coffee . In addition , this depends on the amount of coffee consumed . For instance , there is increased blood flow and alertness but excess will cause insomnia and other issues. I have therefore linked videos of the effect of caffeine in this link. Click here.  The other interactions of caffeine with the body is illustrated here.  Click here.

Trigonelline may decrease bone density and mineralization . This can affect the bone strength and function but, this was based on experiments on rats and not on humans. Therefore, the statement could be a huge assumption when linked to humans and this is shown in the link here.   Moreover, full details of the effects of trigonelline is shown in this link here.

Chlorogenic acid may impact the bitter taste found in coffee. This might be due to the roasting process and this occur because the roasting is not the same for every brand of coffee. However , it may have several important benefits in addition to the bitter taste. Full effect of chlorogenic acid in the body is shown and is linked here.

Finally, it is worth to know,  that coffee may have good and even therapeutic effects. However,  drinking too high amounts of coffee will lead to increased  amounts of  constituents compounds. Too high amounts (over 400mg)  and more can cause side effects such as lack of sleep.