LEVEL OF CAFFEINE IN RAW AND ROASTED COFFEE BEAN VARIETIES OF HARARGHE, ETHIOPIA

Abstract

Due to the chemical compound called caffeine found in coffee bean, coffee is an important commodity culturally, commercially and economically in the world. But, unless consumed based on the recommended food intake, beside its advantages, caffeine has many disadvantages that affect the purpose for which coffee is cultivated. Therefore, the caffeine content in coffee bean should be known. Concerning determination of caffeine in different Ethiopian coffee bean, only few reports are available. Particularly, there are no reports on the level of caffeine for different varieties of coffee, Harar A, Harar B, and Harar C, grown around Hararghe. The classifications Harar A, B and C are based on multiple parameters such as size, shape, color and flavor. Such classifications can be regarded as indicators of the intrinsic properties of the coffee under investigation. So, this research was aimed to investigate the amount of caffeine in raw and roasted Hararghe coffee varieties using UV-Vis spectrometer. To achieve this objective, the three varieties of Hararghe coffee were collected from Ethiopian Commodity Exchange (ECX), Dire Dawa branch. Then, the level of caffeine was determined from both raw and roasted coffee bean after extracting it by dichloromethane using liquid-liquid extraction method. The concentration for raw coffee bean of Harar A, B and C were 512, 340.8 and 314 mg/100 g, respectively. Similarly, the concentration for the roasted coffee been of Harar A, B and C were 914, 772.2 and 640 mg/100 g, respectively. Based on the results, a higher concentration was observed in the roasted than the raw coffee bean. When compared with reported data of caffeine content of coffee bean, the level of caffeine obtained from both the raw and roasted bean in this study was lower.