2.4.4. FRAP – the ferric reducing/antioxidant power assay A modified method of Politeo, Jukic, and Milos (2007) was used.
A working FRAP solutionwas prepared by mixture of 10 volumes of 300 mmol L1 acetate buffer (pH¼3.6) with one volume
10 mmol L1 TPTZ solution and one volume 20 mmol L1 FeCl3 solution. TPTZ was dissolved in 40 mmol L1 hydrochloric acid.
Absorbency of prepared FRAP solution at l¼593 nm in t ¼0 was 0.120 0.010. Honey samples were added in amounts of 10 mL (0.5 g mL1) and AOA was calculated as absorbency increase from five parallel determinations and expressed in mg ascorbic acid equivalent in kg of honey.