Olive oil
Olive oil contains traces of phenolics (about 0.5%), such as esters of tyrosol, hydroxytyrosol, oleocanthal and oleuropein, which give extra virgin olive oil its bitter, pungent taste, and are also implicated in its aroma. Olive oil is a source of at least 30 phenolic compounds, among which are elenolic acid, a marker for maturation of olives, and alpha-tocopherol, one of the eight members of the Vitamin E family. Oleuropein, together with other closely related compounds such as 10-hydroxyoleuropein, ligstroside and 10-hydroxyligstroside, are tyrosol esters of elenolic acid.