title: On-line HPLC-DPPH screening method for evaluation of radical scavenging phenols extracted from apples (Malus domestica L.).
abstract: An on-line HPLC-DPPH screening method for phenolic antioxidants in apple methanol/water (80:20, v/v) extracts was applied. The determination of antioxidants was based on a decrease in absorbance at 515 nm after postcolumn reaction of HPLC-separated antioxidants with the 2,2'-diphenyl-1-picrylhydrazyl radicals (DPPH*). Each of the antioxidants separated by the HPLC column was observed as a negative peak corresponding to its antioxidative activity. The on-line method was applied for quantitative analysis of the antioxidants. A linear dependence of negative peak area on concentration of the reference antioxidants was observed. For validation of the on-line method the limit of detection, LOD (microg/mL), and the limit of quantification, LOQ (microg/mL), of the phenolic compounds were determined. Comparison of the UV and DPPH radical quenching chromatograms with authentic compounds identified catechin, chlorogenic acid, caffeic acid, epicatechin, and phloridzin in the apple cultivars (Lobo, Golden Delicious, and Boskoop), and the distribution of total antioxidant activity was calculated.
authors.affiliation: Institute of Food Chemistry and Technology, Graz University of Technology, Petersgasse 12, A-8010 Graz, Austria.
authors.forename: Donata
authors.initials: D
authors.lastname: Bandoniene
authors.forename: Michael
authors.initials: M
authors.lastname: Murkovic
mesh_terms: D000975:Antioxidants / Q000032:analysis; D015764:Bepridil / Q000031:analogs & derivatives*; D001713:Biphenyl Compounds; D002109:Caffeic Acids / Q000032:analysis; D002392:Catechin / Q000032:analysis; D002726:Chlorogenic Acid / Q000032:analysis; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016166:Free Radical Scavengers; D005609:Free Radicals; D005638:Fruit / Q000737:chemistry*; D007700:Kinetics; D027845:Malus / Q000737:chemistry*; D010636:Phenols / Q000032:analysis*; D010695:Phlorhizin / Q000032:analysis; D010851:Picrates; D011786:Quality Control
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D002109:Caffeic Acids; D016166:Free Radical Scavengers; D005609:Free Radicals; D010636:Phenols; D010851:Picrates; D002726:Chlorogenic Acid; D015764:Bepridil; D002392:Catechin; D010695:Phlorhizin; C004931:1,1-diphenyl-2-picrylhydrazyl; C040048:caffeic acid