Phenolic compounds and antioxidant capacity of selected fruit species

Etanolni ekstrakti, pripremljeni od četiri vrste voća, korišteni su za određivanje sadržaja fenolnih spojeva. Odabrane vrste voća: naranča (Citrus sinensis), mandarina (Citrus reticulata), jabuka (Malus domestica Borkh.) i borovnica (Vaccinium corymbosum) nabavljene su na lokalnoj zagrebačkoj tržnici. Ukupni fenoli, ukupni flavonoidi i ukupni neflavonoidi određivani su primjenom Folin-Ciocalteu metode. Antioksidativni kapacitet istraživanih vrsta voća određivan je upotrebom: 2,2-difenil-1-pikrilhidrazil radikal metode (DPPH), [2,2'-azinobis(3-etilbenzotiazolin-6-sulfonske kiseline)] radikal kation metode (ABTS) i Ferric Reducing Antioxidant Power metode (FRAP). Od svih istraživanih vrsta voća najveća količina polifenolnih spojeva određena je u borovnici. U svim istraživanim uzorcima utvrđen je visoki antioksidativni kapacitet. Također je utvrđena dobra korelacija između fenolnih spojeva i antioksidativnog kapaciteta primjenom FRAP i ABTS metoda.Ethanol extracts prepared from four fruit species obtained on local market in Zagreb, namely orange (Citrus sinensis.), mandarin (Citrus reticulata), apple (Malus domestica Borkh.) and blueberry (Vaccinium corymbosum ) were examined for their phenolic components. Total phenolics, total flavonoids and total nonflavonoids were determined by the Folin-Ciocalteu method. Antioxidant capacity of investigated plant extracts were examined using: 2,2-diphenyl-1-picrylhydrazyl assay (DPPH), Ferric reducing antioxidant power assay (FRAP) and [2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)] radical cation assay (ABTS). Among investigated fruit species the highest amount of all group of phenols in blueberry fruits was examined. Among all investigated samples very high antioxidant capacity was determined. Very good correlation between phenolics and antioxidant capacity was examined using FRAP and DPPH methods