CHARACTERIZATION OF MINOR POLAR COMPOUNDS IN VIRGIN OLIVE OIL USING COMPREHENSIVE TWO-DIMENSIONAL GAS CHROMATOGRAPHY WITH TIME-OF-FLIGHT MASS SPECTROMETRIC DETECTION

Virgin olive oil (VOO) is a high-quality food product from a nutritional standpoint, and also 3010possesses many beneficial health characteristics. The minor polar compounds (MPCs) in virgin olive oil constitute a small fraction (1-2%) of the total chemical composition, but contain a rich array of natural products that include free fatty acids, acylglycerols, aliphatic alcohols, sterols, and phenolic compounds. A number of relevant MPCs have already been identified that play an important role during the manufacturing process (extraction, conservation of sensory properties, long-term storage of the final product), and after the product is in use by the consumer (strong antioxidants and radical scavengers that are important for protection against chronic conditions such as cancer and atherosclerosis). However, the complexity of the MPC fraction has precluded its detailed characterization for better elucidation of potential key trace compounds that also have significant effects for this high-quality food product. The analysis of MPCs in VOO has previously been achieved using reversed-phase HPLC with UV-Vis diodearray detection (DAD). HPLC/DAD analysis presents a challenge, however, in the determination of the total MPC profile because it is limited to the compounds that absorb at select wavelengths of interest, and is not capable of identifying significant compound classes such as the free fatty acids, monoacylglycerols, and triterpenic acids. In this work we report our investigations on the potential use of comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (GC×GC/TOF MS) for the improved screening of the MPC profiles in VOO. Methanolic extracts of oil samples from two different cultivars (Ascolana tenera and a 1:1 blend of Frantoio and Leccino) were analyzed for their MPCs as trimethylsilyl derivatives. Over 300 compounds were recognized by the MS library, and catalogued according to their bi-dimensional retention coordinates. A new approach for the tentative identification of known and new analytes in blind screening protocols was developed.