Study of Antioxidant Effects of Selected Types of Coffee

Abstract

Coffee is a rich source of dietary antioxidants which protects the human body against the effects of dangerous free radicals. The aim of this study was to determine and compare the antioxidant activity, content of total phenols and flavonoids in selected types of coffee with respect to the way of their processing. The individual coffees were investigated with regard to their origin and composition. The antioxidant effects were determined by the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging assay. The content of total phenols was analysed by the Folin-Ciocalteu method and the content of flavonoids in the coffee extracts was determined by a colorimetric method. The highest antioxidant activity was exhibited by the extract of unroasted ground 100 % green coffee Arabica (89.55 %), and the high scavenging of free radicals was achieved also by the extracts of roasted ground 100 % coffees Arabica and Robusta. The highest levels of total phenols (77.54 µg.ml−1) and flavonoids (1.74 µg.ml−1) were measured in the extract of unroasted ground 100 % green coffee Arabica. High levels of these substances were found also in extracts of roasted ground 100 % coffees Arabica and Robusta. The lowest levels of total phenols (31.24 µg.ml−1) and flavonoids (0.91 µg.ml−1) were detected in the extract of instant coffee Arabica. The processing of coffee by roasting decreased the level of the investigated antioxidant components but considerably improved the taste and aroma, the properties that make coffee one of the most popular drinks in the world.

Keywords

• antioxidant effect
• coffee arabica (l.)
• free radicals