Coffee Constituents

Coffee has been for decades the most commercialized food product and most widely consumed beverage in the world. Since the opening of the first coffee house in Mecca at the end of the fifteenth century, coffee consumption has greatly increased all around the world. In 2010, coffee production reached 8.1 million tons worldwide [1]. This represents more than 500 billion cups, with the United States, Brazil, Germany, Japan, and Italy being the major consumer countries. However, per capita consumption in North European countries such as Finland, Norway, Denmark, and Sweden may reach 8 kg/year, more than two times that of the United States or Brazil [2]. The reasons for this continuous increase in coffee consumption include improved cup quality through selection of varieties and breeding, better agricultural practices; the creation of specialty shops, and a change in coffee’s image through the dissemination of information on the health benefits of long-term coffee consumption. Today, coffee is considered a functional food, primarily due to its high content of compounds that exert antioxidant and other beneficial biological properties. The characteristic flavor and richness of coffee aroma make it a unique beverage, with almost a thousand volatile compounds identified in roasted coffee [3]. The coffee tree belongs to the Rubiaceae family, genus Coffea. Although more than 80 coffee species have been identified worldwide [4], only two are economically important. Coffea arabica, also known as Arabica coffee, is responsible for approximately 70% of the global coffee market, and Coffea canephora or Robusta coffee (commercial name of one of the main C. canephora cultivars) accounts for the rest [1,5]. Arabica and Robusta coffees are different in many ways, including their ideal growing climates, physical aspects, chemical composition, and characteristics of the brew made with the ground roasted seeds. This chapter will focus on the chemical composition of these two coffee species, including the nonvolatile and volatile compounds important for flavor, quality, and health-promoting actions. To understand the chemical changes that occur during coffee production, we will briefly address the main technological processes green coffee seeds undergo before they are consumed as brewed coffee beverage.