Determination of Phospholipids in Olive Oil by 31P NMR Spectroscopy

A nondestructive analytical method based on NMR spectroscopy was developed for the determination of phospholipids in olive oil. The phospholipids extracted from virgin olive oil with a mixture of ethanol/water (2:1 v/v) were identified and quantified by high resolution31P NMR spectroscopy. The main phospholipids found in olive oil were phosphatidic acid, lyso-phosphatidic acid, and phosphatidylinositol. Validation of the 31P NMR methodology for quantitative analysis of phospholipids in olive oil was performed. Sensitivity was satisfactory with detection limits of 0.25-1.24 µmol /mL. In addition, the composition of fatty acids in phospholipids model compounds and those in olive oil samples was estimated by employing one- and two-dimensional 1H NMR. The results indicated that the fatty acid composition in phospholipids and triacylglycerols of olive oil was similar.