Identification of (+)-pinoresinol and (+)-1-acetoxypinoresinol in virgin olive oil by capillary zone electrophoresis (CZE) and high performance liquid chromatography-mass spectrometry detection (HPLC-MSD)

In the last few years, the use of capillary electrophoresis (CE) in food analysis has considerably increased. Particularly, studies by CE of minor polar components, having antioxidant properties, are still scattered. Between those, simple and complex phenolic compounds of virgin olive oil are important for the protection against lipid oxidation and for the sensory properties. Recently, two phenolic compounds belonging to the lignan family, (+)-pinoresinol and (+)-1-acetoxypinoresinol, showing chemoprotective effects, have been identified in virgin olive oil. In this paper (+)-pinoresinol and (+)-1-acetoxypinoresinol were identified and collected by HPLC-MSD from olive barks and from virgin olive oil extracts, respectively. These compounds were also separated by a rapid capillary zone electrophoretic (CZE) method, in some virgin olive oil extracts and (+)-1-acetoxypinoresinol was one of the most abundant peaks, while (+)-pinoresinol was found in trace. By CZE were also separated other typical phenolic olive oil components, namely tyrosol, hydroxytyrosol, phenolic acids and a secoiridoid component. The CZE separation was performed within 10 min, using a 40 cm x 50 μm capillary and a 45 mM sodium tetraborate buffer (pH 9.60), at 27 kV and 30°C.