Polyphenols and antioxidant capacity in products of mandarin and clementine

Cilj ovog rada je odrediti ukupne i pojedinačne (hesperidin i naringin) fenolne spojeve u želiranim proizvodima mandarine (Citrus Unshiu Marcovitch) sorte Saigon i klementine (Citrus Clementine) sorte Corsica SRA 63. Od svake vrste voća proizvedena su tri džema i marmelada na kojima su provedena ispitivanja. Ukupni fenolni spojevi i flavonoidi određivani su spektrofotometrijski i to flavonoidi dvjema metodama, a hesperidin i naringin (flavanon glikozidi) primjenom HPLC metode uz UV- Diode Array detekciju. Proizvodi mandarine i klementine imaju slične udjele svih ispitivanih fenolnih spojeva iako mandarina ima uglavnom nešto veće vrijednosti. Antioksidacijski kapacitet određen je primjenom DPPH, FRAP i ABTS metode. Porast udjela fenolnih spojeva i antioksidacijskog kapaciteta nije pokazao izrazitu pravilnost obzirom na udio pulpe u proizvodima. Iz skupine flavanon glikozida veći udio u svim proizvodima pokazuje hesperidin. Na temelju koeficijenata korelacije DPPH metoda pokazala se neprikladnom, dok se FRAP metoda pokazala najboljom za određivanje antioksidacijskih kapaciteta želiranih proizvoda mandarine i klementine.The aim of this study was to determine bioactive compounds, the total and single polyphenols in products of mandarin (Citrus Unshiu Marcovitch) cv. Saigon and clementine (Citrus Clementine) cv. Corsica SRA 63. Three jams and one marmelade were made and submited to the analysis. Total phenolic content was measured using the Folin-Ciocalteau method, flavonoids were measured by two methods, and HPLC method was used for the analysis of individual flavanone glycosides. Three different methods (DPPH, FRAP and ABTS) were used to determine the antioxidant capacity. The results showed similar values for both kinds of products, but mandarine products, in general, showed higher levels of all analysed polyphenols. The flavanone glycosides, determined in investigated samples by HPLC method are: hesperidin and naringin. Hesperidin was dominant in all products. According to FRAP method, all samples posses evident antioxidant capacity