Extra virgin olive oil, a key ingredient of Mediterranean Diet, was a widley investegated matrix. Olive oil is mainly composed of triacylglycerols (Ca. 98%); instead, polar lipids, in particular phospho, sulfo, and glycolipids is the minor component (2%) [1]. The aim of this work is to characterize and identify the olive oil polar lipid profile allowing to provide a chemical identity to olive oil and evaluate possible adulaterations [2]. The lipids extraction methods most widley used are Folch [3] or Bligh and Dyers [4], followed by clean-up or enrichment procedure. Firstly, the extra virgin olive oil samples will be subjected to pretreatment, prior to the analysis, by comparison of different liquid-liquid extractions and solid phase enrichment. Lipids will be extracted by using various solvent mixtures, for example hexane with ethanol, isopropanol, ethyl acetate to achieve greater polar lipids recovery. Finally, enrichment optimization methods will be optimized by applying a different SPE cartridges reported in literature [5,6,7]. Two solid phase extraction based on weak anion exchange (WAX) and griphitized carbon black (GCB) will be performed obtaining the best enrichment especially for lower aboundant polar lipids. Moreover, lipids identification will be performed with Lipostar, new comprehensive software for lidomic study. Being polar lipids profile in this matrix slightly characterized, but it represents an important target especially for the Mediterranean country economy, with this project could be characterized more exhaustively than the state of the art.
The goal of the project is to obtain the lipidomic profile of the principale component in mediterranean diet, namely extra virgin olive oil. In this way, bioactive lipids profile could be characterized more exhaustively than the current state of the art.
1) First comprehensive characterization of polar lipids in extra virgin olive oil, a principal component of mediterranen diet will be performed. This part will take into consideration: polar lipid extract preparation, enrichment procedure and lipids identification. Firstly, a sample preparation procedure will be devised by comparison of different extraction procedures and solid phase enrichment, adaptation to the olive oil matrix, to maximize lipid recovery, and lipid identification. This step coupled with the optimized lipid separation will help achieve a larger coverage of polar lipid species in extra virgin olive oil and allow to characterize polar lipid profile.
2) Improvement of current Lipostar database with lipid classes focusing particularly on the fosfo-, sulfo-, and glycolipid species. Exact precursor masses and fragmentation data will be collected and added to the database, to increase the probability of lipid identification in extra virgin olive oil.
3) Lipids profile characterization of different extra virgin olive oil, coming from different regions, will be carried out.
4) In addition, bioactive polar lipids will be quantified throughout an optimized extraction procedure. Olive oil species will be characterized both from a qualitative point of view and from a quantitative point of view.