The total polar fraction and individual phenols present in virgin olive oil were tested for their antioxidant effect in refined
olive oil. Hydroxytyrosol and caffeic acid showed protection factors greater than BHT. Protocatechuic and syringic acid were
also found to have antioxidant activity. Tyrosol, p-hydroxyphenylacetic acid, o-coumaric acid, p-coumaric acid, p-hydroxybenzoic
acid and vanillic acid had very little or no effect, and their contribution to the stability of the oil is negligible.
Key Words Antioxidant activity - olive oil - phenols - polar fraction - protection factor