2.4.2. DPPH (1,1-diphenyl-2-picrylhydrazyl) assay
For DPPH assay the modified method of Brand-Williams, Culivier, and Berset (1995) was used. Fresh DPPH methanolic solution (Aผ 0.200_ 0.010) was prepared before every measurement; 2 mL DPPH solution was inserted into a plastic cuvette and absorbency in time tผ 0 min (t0)was measured. Then a 10 mL honey sample was added (0.5 g mL_1). The solution was stirred and left to stand for 20 min at laboratory temperature and then absorbency at lผ 515 nm was measured. AOA was calculated as a decrease of absorbency from the equation: AOA๐% ผ 100 _ ๐At20=At0 _ 100 (1) and expressed in mg ascorbic acid equivalent (AA eq.) in kg ofhoney. Average values were determined from five parallel determinations.