ABSTRACT
Chemical composition of coffee beans: an overview Michael N. Clifford, University of Surrey, UK; Iziar A. Ludwig, Universitat de Lleida, Spain; and Alan Crozier, University of California Davis, USA
1 Introduction
2 Overall composition of green coffee
3 Roasting and associated transformations
4 Chlorogenic acids in green coffee beans
5 Chlorogenic acids in roasted coffee beans, instant coffee and beverage
6 Caffeine
7 Trigonelline
8 Diterpenes
9 Melanoidins
10 Production of volatiles
11 Conclusion and future trends
12 Where to look for further information
13 References
Two coffee species are of economic importance, namely Coffea arabica, commonly known as Arabica coffee, which accounts for ~60% of the world’s production, with the remaining ~40% coming from Coffea canephora var. Robusta (FAS/USDA 2016). In general, Arabica coffee bean brew is appreciated for its superior cup quality and aroma, whereas Robusta brew possesses a more aggressive flavour and contains higher amounts of soluble solids and caffeine (Farah, 2012). Chemical composition of a coffee brew depends, besides variety, on several other factors, such as climatic and processing conditions, roasting, grinding and barista procedures. The pleasant aroma, taste and brown colour of brewed coffee are all a consequence of the roasting process that leads to profound changes in the chemical composition of the beans (Belitz et al., 2009).
