Effect of the "Ottobratica" variety ripening stage on the phenolic profile of the obtained olive oil

A study about phenols' composition of virgin oil from olives of the ottobratica variety was conducted by spectrophotometric examination and by liquid chromato-graphic analysis (HPLC). Samples of three olive oils of this Calabrian autochthonous cultivar (Italy) were collected in October, November and December 2007 and some quality indices were evaluated. In particular, the free acidity increased during ripening over the 2% value in December sample. The three oils revealed a peroxide number less than 10 mEq of o 2/kg. concerning the total phenols' content, the initial amount lowered from 408 to 190 mg of gallic acid/kg oil during ripening and successive processing. finally, 18 phenolic compounds were detected by hplc analysis and 16 of them were quantified: simple phenols (hydroxytyrosol and tyrosol); secoiridoids derivatives (hydroxytyrosol acetate, dialdehydic form of the decarboxymethyl oleuropein aglycon, dialdehydic form of the decarboxymethyl ligstroside aglycon, dialdehydic form of the oleuropein aglycon, dialdehydic form of the ligstroside aglycon); phenolic acids (vanillic, ferulic, 4-hydroxybenzoic, p-cumaric, and o-cumaric acids); lignans (1-acetoxypinoresinol and pinoresinol); flavonoids (luteolin and apigenin).