Determination of total phenolic content and antioxidant activities of five different brands of Ethiopian coffee

Abstract

High consumption of coffee has been considered to have negative health consequences, often attributed to the stimulant effects of caffeine. However, coffee is also one of the largest sources of antioxidants in the diet and contains various compounds with potential beneficial effects on glucose metabolism, inflammation and blood vessel function. The present work was carried out to determine the total phenolic content and antioxidant activity of five different Ethiopian coffee varieties, namely Sidamo, Yirgacheffe, Harare, Wollega and Jimma coffee. Total phenolic content was determined by the Folin-Ciocalteu method and expressed as Gallic acid equivalents whereas antioxidant activities were determined by 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, reducing power and total antioxidant activity. The tested coffee beans contained appreciable amounts of total phenolic contents (54.87-80.51 g GAE /g); DPPH Scavenging capacity (73.33-84.16%), reducing power (0.634 ± 0.62 – 0.887 ± 0.14) and total antioxidant activity (0.198-0.346) at 0.2 mg/mL extract concentration. The study showed that total phenolic content and antioxidant activities of the coffee extracts were capable of protecting against free radical mediated damage and may have applications in preventing and curing various diseases.