Browsing by Author "Tasew Tsedale"

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    In Vitro Antibacterial and Antioxidant Activities of Field Collected (Jimma and Yirgacheffe) Coffee Beans and Roasted-Ground Shop Coffee From Addis Ababa
    (Addis Ababa University, 2019-05-03) Tasew Tsedale; Mamo Hassen (PhD)
    Coffee has long been among the first beverages consumed worldwide and most traded commodities. The coffee extract is reported to show antibacterial and antioxidant activities. Ethiopia as the land of origin of the Coffea arabica and producer and exporter of different coffee varieties has not yet developed enough studies on the health aspects of coffee. This study aimed at investigating the antibacterial and antioxidant activities of coffee bean samples collected from two coffee-growing regions of Ethiopia, Yirgacheffe and Jimma, as well as roasted ground coffee bean sample from a coffee shop in Addis Ababa. The antibacterial test was conducted on medium-roasted, boiled water extracts. Qualitative phytochemical test was conducted to assess the availability of most common secondary metabolites on roasted sample extracts. Agar well-diffusion bacterial susceptibility test, minimum inhibitory concentration test and minimum bactericidal concentration tests were determined against eight bacterial strains to assess the antimicrobial activities of the coffee samples using chloramphenicol as positive control. The antioxidant activity assessment was done following the DPPH IC50 percent inhibition test and DPPH antioxidant content measure procedure on light roasted and green coffee bean samples as well as light roast shop sample methanol extracts. The susceptibility test data was analyzed using (Minitab.v17.1.0.) one-way ANOVA mean ± SD (p˂0.05). All coffee samples showed strong antibacterial and antioxidant activities. However, samples from Yirgacheffe, Jimma and the shop sample showed significant variation in both their antibacterial as well as antioxidant activities. The different coffee bean samples activity was also variable against the different test bacteria. The study highlighted the health importance of Ethiopian coffee using field samples. In-depth investigations using samples from wider agro-ecological regions and localities and testing fractionates is necessary.