Antioxidant capacity and physicochemical parameters of rape honey (Brassica sp.)

Zadatak ovog rada bio je karakterizirati med od uljane repice (Brassica sp.) s naglaskom na antioksidativni kapacitet. Antioksidativni kapacitet meda ovisi prvenstveno o njegovu botaničkom podrijetlu, a najčešće se povezuje s udjelom fenola i bojom. Od fizikalno-kemijskih parametara određeni su: udio vode, električna provodnost, boja, aktivnost dijastaze, udio HMF-a, omjer fruktoze i glukoze te njihov zbroj. Udio fenola određen je modificiranom Folin-Ciocalteu metodom dok je antioksidativni kapacitet određen FRAP i DPPH metodama. Rezultati analiza pokazali su da med od uljane repice karakterizira nizak omjer fruktoze i glukoze s prosječnom vrijednosti 1,00±0,03 te da spada u kategoriju jako svijetlo žutih medova prema Pfund-ovoj skali (prosječna vrijednost 37,5±7,9 mm Pfund). Udio ukupnih fenola nalazio se u rasponu 108,2-152,6 mg galne kiseline/kg meda, dok je antioksidativni kapacitet određen FRAP metodom bio 144,6-232,3 μM Fe(II), a onaj određen DPPH metodom 17,51-29,09 mg/ml.The aim of this study was characterisation of rape honey (Brassica sp.) with emphasis on antioxidant capacity. Antioxidant capacity of honey primarily depends on its botanical origin and generally is correlated with phenolic content and honey colour. Following physicochemical parameters were determined: water content, electrical conductivity, colour, diastase activity, HMF content, fructose (F) and glucose (G) ratio and their sum. Total phenolic content was determined by modified Folin-Ciocalteu method while antioxidant capacity of honey was determined by FRAP and DPPH methods. Results showed that rape honey has low F/G ratio with average value of 1,00±0,03 and according to the Pfund scale belongs to category extra light amber (the average value 37,5±7,9 mm Pfund). Total phenolic content was 108,2-152,6 mg gallic acid/kg of honey, while antioxidant capacity determined by FRAP method was 144,6-232,3 μM Fe(II) and antioxidant capacity which was determined by DPPH method was 17,51-29,09 mg/ml