Introduction

Coffee is one of the beverages that are with us in every moment of our lives. It is prepared from roasted coffee beans which are in the Coffea genus. And all coffee plants belong to the family of Rubiaceae1. By separating the seed from the coffee fruit, a green raw product emerges as known as unroasted coffee. After roasting, it becomes a consumable product. Then it takes its place on our tables as a cup of coffee by adding hot water and going through different processes.

Image 1:

Image 1: A cup of black coffee1.

Among the many species of the Coffee genus, these two are commercially produced: Coffee arabica and Coffee canephora (also known as ‘robusta‘). These two differ due to the regions in which they are grown and many other factors1,2.

C. arabica

It was first described in 1753. It makes up almost %60 of the coffee consumed.  The best-known varieties of C. arabica are ‘typica’ and ‘bourbon‘. Other varieties that developed from these are caturra (Brazil, Colombia), Mundo Novo (Brazil), Tico (Central America) etc… It matures in 7-9 months and grows at higher altitudes than robusta. And it is self-pollinating. C. arabica has a bitter and sharp flavor. An important difference that distinguishes arabica coffee from robusta is that it is often susceptible to attacks by pests and diseases. Therefore, resistance is an important issue in plant breeding programs.

Robusta

It was first described in 1895. It makes up about 40% of the coffee consumed. ‘Robusta’ is a term for C. canephora’s widely grown variety. It matures in 10-11 months and grows at lower altitudes than C. arabica. It also requires crossing. Robusta beans are usually grown in the eastern hemisphere, especially in Africa, India, and Indonesia. It has about twice as much caffeine as arabica. It is easier to grow robusta due to the climate and geographical location. Robusta is characterized as softer and sweeter.

Coffee is selectively bred due to characteristics such as taste, quality, bean size, shape, and caffeine content. Crosses between arabica and robusta aim to improve the disease resistance of arabica or to improve the cup quality of robusta. Arabica has 44 chromosomes, robusta has 22 chromosomes, while the natural hybrid of each other, Hibrido de Timor, has 44 chromosomes. The cross of Hybrido de Timor and Caturra is resistant to coffee leaf rust.

Image 2:

Image 2: Coffee Arabica berrys2.

Where was the coffee found until it took this form and came to our tables? Coffee began to be consumed in Arabia, where it got the name ‘qahwah’ in the 16th century2. It was also first used by Sufis to stay awake in religious rituals3.

In the 17th century, it was moved to Europe with Venetian merchants. And then, because of the European colonization of Asia, Africa, and America, coffee plantations were established in various parts of the world. That’s how coffee began to be one of the most popular things around the world4.

In 1583, Leonhard Rauwolf gave this description of coffee after the trip to the Near East:

“A beverage as black as ink, useful against numerous illnesses, particularly those of the stomach. Its consumers take it in the morning, quite frankly, in a porcelain cup that is passed around and from which each one drinks a cupful. It is composed of water and the fruit from a bush called bunnu.”

In recent years, if we look at the per capita consumption around the world, the Scandinavian countries are at the top of the list5. Also, coffee, which we sometimes consume more than water, binds us to itself with the caffeine it contains.

Caffeine

  • Caffeine is a white crystalline purine, a bitter alkaloid with the formula C8H10N4O2. It was named by the German chemist Friedrich Ferdinand Runge in 1819. Its name is derived from coffee6.
  • It’s generally found in coffee, tea, cola, and cacao. Apart from coffee and tea, it is found in high doses in guarana, which is a tropical plant especially common in Brazil. Guarana contains guaranine, a close relative of caffeine. Another substance that has similar properties to caffeine and influences the nervous system is tannin, which is found in tea.
  • The average caffeine consumption per day in the United States is 200 mg. Ingested caffeine absorbed in the blood in 1-2 hours. It is absorbed by most tissues, and the remaining products are excreted in the urine7.
  • According to the International Olympic Committee (IOC), caffeine is a “controlled or restricted substance”. So how much does caffeine affect performance? The studies in the 1970s suggested that caffeine increased endurance performance by increasing the adrenaline in the blood. However, subsequent studies in the 1980s suggested that caffeine does not have an ergogenic effect. According to recent studies, the mechanism of these improvements is unclear. But still, athletes can legally improve their performance by using caffeine in appropriate doses7,2.
  • Caffeine is found in many prescription and over-the-counter medications. These drugs are for many different ailments, such as headaches, staying awake, colds, and loss of appetite. And caffeine content varies between 7-200 mg per tablet. To make a rough calculation, caffeine is usually taken less than 300 mg a day, which is equal to about 5 cups of instant coffee or tea8.
  • Since it does not accumulate in the body, its effects are short-term and temporary.
  • People’s reactions to caffeine may vary. For example, a pregnant woman can keep caffeine in her body 3 times longer than a normal person. People who smoke cigarettes, on the contrary, remove it from their bodies 2 times faster8,2.
  • Of all the physiological effects of caffeine, the best known is that it stimulates the nervous system. This allows a person drinking a cup of coffee or tea to be alert and more concentrated8,3.
  • Another short-term effect is an increase in blood pressure, plasma renin, serum-free fatty acids, the production of urine and gastric acid8,4.

Conclusion

In recent years, Coffea has been investigated using recombinant DNA technology and tissue culture techniques. By adding new genes for traits, it may be possible to produce plants with any combination of required traits1,5.

References:

  1. London: International Coffee Organization. Archieved on 24 March 2009. https://www.ico.org/botanical.asp
  2. Weinberg, Bennett Alan; Bealer, Bonnie K. (2001). The World of Caffeine: The Science and Culture of the World’s Most Popular Drug. New York: Routledge
  3. Brill, E. J. (1993). EJ Brill’s First Encyclopaedia of Islam: 1913-1936. S-Ṭaiba(Vol. 7). Brill.
  4. “Suave Molecules of Mocha” — Coffee, Chemistry, and Civilization | 03.7.2005 | Hannah Meyers | Food, Science https://www.newpartisan.com/home/suave-molecules-of-mocha-coffee-chemistry-and-civilization.html
  5. Bernard, Kristine (5 January 2018) https://www.worldatlas.com/articles/top-10-coffee-consuming-nations.html
  6. https://www.dictionary.com/browse/caffeine
  7. Caffeine and Exercise Performance by Lawrence L. Spriet, Ph.D., FACSM (Chair) and Terry E. Graham, Ph.D., FACSM.   http://www.acsm.org/docs/current-comments/caffeineandexercise.pdf
  8. Evaluation of Caffeine Safety, a scientific status summary by the Institute of Food Technologists’ Expert Panel on Food Safety and Nutrition, 1987. Food Technology, Institute of Food Technologists, Chicago, 41(6):105-113.June 1987 http://www.ico.org/caffeine.asp

Image References:

  1. https://www.tastingtable.com/img/gallery/coffee-brands-ranked-from-worst-to-best/l-intro-1645231221.jpg
  2. http://botanyphoto.botanicalgarden.ubc.ca/wp-content/uploads/2015/09/coffea-arabica.jpg

Inspector: Furkan EKER

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