Antioxidant Activity of Coffee Model Systems

Coffee model systems prepared from combinations of chlorogenic acid (CGA), Nα-acetyl-1-arginine (A), sucrose (S), and cellulose (C) were roasted at 240 °C for 4 min prior to analysis by UV−visible spectrophotometry, capillary zone electrophoresis (CZE), and the ABTS radical cation decolorization assay. The A/CGA/S/C and A/S/C systems were also fractionated by gel filtration chromatography. Antioxidant activity of the systems showed a positive, nonlinear relationship with the amount of CGA remaining after roasting. Sucrose degradation was a major source of color in the heated systems. There was no relationship between antioxidant activity and color generation. Keywords: Coffee model systems; antioxidant activity; chlorogenic acid; ABTS radical cation assay; capillary electrophoresis