Comparison of antioxidant activity of different flours determined by DPPH and ABTS method

The objective of this study was to compare antioxidant activity of different flours (rye, barley, buckwheat, yellow corn and white corn) determined by DPPH and ABTS method. Antioxidant activity determined in extracts of flours by DPPH method ranged from 20.92 to 58.95 μmol TE/100 g and from 54.91 to 95.32 μmol TE/100 g by ABTS method. The lowest antioxidant activity was determined for yellow and white corn by both methods. The highest antioxidant activity was determined for barley, 58.95 μmol TE/100 g (DPPH method) and buckwheat, 95.32 μmol TE/100 g (ABTS method). Determination of antioxidant activity was also conducted by “QUENCHER” method which is based on using free radicals directly on sample without prior extraction. Values of antioxidant activity obtained from extracts, and directly from samples, were compared. Antioxidant activity was higher when “QUENCHER” method was used as evaluation method. ABTS antioxidant activity was higher in contrast to DPPH antioxidant activity (regardless of sample preparation) probably due to higher selectivity of DPPH free radicals. Also, EC50 (efficiency coefficient) and ARP (antiradical power) values were determined. Higher EC50 value was determined by DPPH method. Lower EC50 means that ARP is higher. The lowest EC50 had buckwheat flour (5.89 mg and 17.38 mg for ABTS and DPPH method, respectively) thus it had the highest ARP value.