Microcomponents of olive oil. Part II: Digalactosyldiacylglycerols from Olea europaea

Two galactolipids, 1 and 2, were isolated and identified both in olive fruits and in olive oil. They are characterized by a low polarity, despite the presence of a diglycosidic unit, giving, in water, micelles. Because of this characteristic, compounds 1 and 2 could be responsible for the stability of the light emulsion typical of freshly produced olive oil. The presence of hydrophilic ortho-diphenolic compounds enhances the antioxidant properties of this oil, particularly in the first period after the production. In addition, the functions present in 1 and 2 are susceptible to hydrolysis and may be easily modified in the alkaline treatment used for the olive oil refining process. For this reason, their presence in olive oil may be a very useful indication of the untreated food product.