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 L_1 acetate buffer (pHผ3.6) with one volume 10 mmol L_1 TPTZ solution and one volume 20 mmol L_1 FeCl3 solution. TPTZ was dissolved in 40 mmol L_1 hydrochloric acid. Absorbency of prepared FRAP solution at lผ593 nm in t ผ0 was 0.120_ 0.010. Honey samples were added in amounts of 10 mL (0.5 g mL_1) and AOA was calculated as absorbency increase from five parallel determinations and expressed in mg ascorbic acid equivalent in kg of honey. 2.5. Statistical analysis Statistical analyses were performed using the software Statistica 8.0 (StatSoft) on the basis of parametrical and non-parametrical tests at the level of significance aผ 0.05 and cluster analysis.