Chemical Characterization of Harar and Berry Coffee Beans with Special Reference to Roasting Effect

The chemical composition of two Abyssinian coffee; Harar and Berry beans, which are dominating the coffee market in the Gulf area were determined. Green beans were heavier and had a higher humidity than roasted beans. Although they did not differ with respect to pH, Harar beans were more acidic (titarable acidity). The oil ( ~ 12%) and protein ( ~13%) contents were comparable with other arabiaca coffee varieties. Roasting did not noticeably alter the levels of these ingredients. Moreover, caffeine followed the same trend. The fatty acids contents of coffee lipid were determined by capillary chromatography. Results revealed that the major fatty acid contents were ahnost similar in both green coffee types. The ranking of the main fatty acids were palmitic, linoleic, stearic and linolenic. The total free amino acid profile indicated that Gln, Asp, Lys and Leu acids were the dominants in the green coffee of both types. While, the minor ones were Arg, Ala, Cys, Val and Phe. In Harar and Berry beans, roasting process did not lead to change the fatty and amino acids either in composition or distribution. In addition the effect of roasting on the coffee matrix also was discussed