coffee extract concentration was plotted to obtain a regression equation, with Trolox being the reference standard to express the antioxidant activity of various extracts of coffee brews. Trolox (0.0125 0.125 mg/mL) or coffee brew extract (5 20 mg/mL) was reacted with an equal volume of TEMPO (1 mM) and a regression equation was determined for Trolox/sample concentration vs.% of inhibition. The ratio between the regression equation slopes for coffee extracts and Trolox, defined the antioxidant capacity of individual extracts of coffee brew. The results are expressed as mmol equivalents of Trolox/g of coffee brew extract (dry matter).