Interactions of ferric ions with olive oil phenolic compounds

• Type: Article in International Scientific Journal
• Date: 2005

Authors

Paiva Martins, F (Author) FCUP; Gordon, MH (Author) Other

Journal

Title: Journal of Agricultural and Food Chemistry

Vol. 53

Pages: 2704-2709

ISSN: 0021-8561

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge - 53 Citations

Scopus - 59 Citations

Scientific classification

FOS: Agrarian Sciences > Other Agrarian Sciences

Other information

Authenticus ID: P-000-3WA

DOI: 10.1021/jf0481094

Abstract (EN): The ferric complexing capacity of four phenolic compounds, occurring in olives and virgin olive oil, namely, oleuropein, hydroxytyrosol, 3,4-dihydroxyphenylethanol-elenolic acid (3,4-DHPEA-EA), and 3,4-dihydroxyphenylethanol-elenolic acid dialdehyde (3,4-DHPEA-EDA), and their stability in the presence of ferric ions were studied. At pH 3.5, all compounds formed a reversible 1:1 complex with ferric ions, but hydroxytyrosol could also form complexes containing > 1 ferric ion per phenol molecule. At pH 5.5, the complexes between ferric ions and 3,4-DHPEA-EA or 3,4-DHPEA-EDA were relatively stable, indicating that the antioxidant activity of 3,4-DHPEA-EA or 3,4-DHPEA-EDA at pH 5.5 is partly due to their metal-chelating activity. At pH 7.4, a complex containing > 1 ferric ion per phenol molecule was formed with hydroxytyrosol. Oleuropein, 3,4-DHPEA-EA, and 3,4-DHPEA-EDA also formed insoluble complexes at this pH. There was no evidence for chelation of Fe(II) by hydroxytyrosol or its derivatives. At all pH values tested, hydroxytyrosol was the most stable compound in the absence of Fe(III) but the most sensitive to the presence of Fe(III).

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 6