Level of caffeine, trigonelline and chlorogenic acids in green coffee (Coffea arabica L.) beans from Amhara region, Ethiopia

Abstract

Ethiopia's Amhara region produces a wide range of local coffee varieties with varying cup characteristics. However, the coffees have not yet been characterized and then trademarked to be included in the country's coffee export market. Thus, the study aimed to determine the levels of caffeine, trigonelline, and chlorogenic acids in green coffee beans grown in different zones of the Amhara region. Eighty green coffee beans were collected from East Gojjam, West Gojjam, Awi, Bahir Dar, and South Gondar zones and determinations were made by HPLC-VWD. Caffeine ranged from 0.78 to 1.55%, trigonelline 0.53–1.27%, and chlorogenic acids 3.29–7.73% (w/w dry mass). Green coffee beans from the Awi zone contained higher mean levels of caffeine, while East Gojjam coffee contained higher levels of chlorogenic acids and trigonelline. Coffee beans from Zegie peninsula exhibited the lowest trigonelline and caffeine levels, while the Awi zone coffee showed the lowest mean concentration of chlorogenic acids. Linear discriminant analysis reveals the possibility of distinguishing coffee samples into their respective cultivation zones with a success rate of 51%.

Keywords

• Amhra region
• Caffeine
• Chlorogenic acids
• Coffee
• Ethiopia
• HPLC