Comment on Addressing Analytical Requirements To Support Health Claims on “Olive Oil Polyphenols” (EC Regulation 432/212)

n a recent paper published in this Journal, Mastralexi et al.(1) compared two methods for analyzing the total contents of hydroxytyrosol and tyrosol in olive oil. Both methods involve the hydrolysis of the derived bound forms of these compounds to their total free forms. The first method was studied by Mulinacci et al.(2) (protocol 1), and it requires a previous extraction of the phenolic compounds from the oil and further hydrolysis with 1 M H2SO4 at 80 °C. The other method proposed by Romero and Brenes(3) (protocol 2) implies direct hydrolysis with 2 M HCl at ambient temperature without a previous extraction step.