title: Protective effects of extra virgin olive oil phenolics on oxidative stability in the presence or absence of copper ions.
abstract: The antioxidant activity of the phenolic fraction of extra virgin olive oil was assessed in samples that had a decreasing content of antioxidants in the presence and absence of copper ions as a catalyst of autoxidation. The oxidation process was evaluated by measuring primary and secondary oxidation products. Changes in phenols and tocopherols were investigated by high-performance liquid chromatography. Both the total phenol content and their antioxidant activity were monitored by spectrophotometric assays (with Folin-Ciocalteu and ABTS*+ reagents). The important role of phenolic compounds (particularly the o-diphenols) in protection from autoxidation was confirmed. However, the tocopherols were more quickly consumed in oils that had the lowest content of o-diphenols, which also showed evidence of an ability to chelate copper. In particular, a dramatic decrease was observed in the isomeric form of decarboxymethyl-oleuropein aglycone after addition of the metal, despite its significant increase in samples stored in the absence of copper.
authors.affiliation: Dipartimento di Scienze degli Alimenti, Università di Bologna, Piazza Goidanich 60, I-47023 Cesena (FC), Italy. bendini@alma.unibo.it
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bendini
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Cerretani
authors.forename: Samuele
authors.initials: S
authors.lastname: Vecchi
authors.forename: Alegria
authors.initials: A
authors.lastname: Carrasco-Pancorbo
authors.forename: Giovanni
authors.initials: G
authors.lastname: Lercker
mesh_terms: D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D003300:Copper / Q000494:pharmacology*; D004355:Drug Stability; D000069463:Olive Oil; D010084:Oxidation-Reduction; D010636:Phenols / Q000032:analysis / Q000494:pharmacology*; D010938:Plant Oils / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D024505:Tocopherols / Q000032:analysis
chemical_list: D000975:Antioxidants; D000069463:Olive Oil; D010636:Phenols; D010938:Plant Oils; D003300:Copper; D024505:Tocopherols