VOLATILE PROFILE OF GREEN COFFEE BEANS FROM COFFEA ARABICA L. PLANTS GROWN AT DIFFERENT ALTITUDES IN ETHIOPIA

This study was aimed to identify volatile compounds of 31 green coffee bean samples and evalute their correlation with altitude of the coffee plants grown in two zones (Gedeo and Jimma) in Ethiopia. A total of 81 different compounds were detected. The contents of dominant volatile compounds in green coffee beans were in the range: trans-linalooloxide (3.24-19.13%), linalool (1.56-21.76%), 2-methoxy-4-vinylphenol (2.34-15.08%) and cis-linalooloxide (1.03-13.27%). In addition, benzene acetaldehyde (0.45-10.97%), 2-heptanol (0.67-8.49%), alpha-terpineol (0.64-6.52%), phenylethyl alcohol (0.44-4.98%) and furfural (0.92-5.3%) were the next dominant compounds. The volatile compounds identified in the green coffee beans are groups of alcohols, aldehydes, ketones, pyrazines, pyridines, and furans. The volatile compounds in green coffee beans showed either weak positive or weak negative correlation with the altitude of coffee plants indicating that variation in altitude of the coffee plants does not significantly influence the volative compounds of green coffee beans.