Use of capillary electrophoresis with UV detection to compare the phenolic profiles of extra-virgin olive oils belonging to Spanish and Italian PDOs and their relation to sensorial properties

BACKGROUND: There is much interest in foods that belong to Protected Designations of Origin (PDO) because the quality and other essential and exclusive characteristics are guaranteed because of a particular geographical environment. We have used a capillary electrophoretic method for the simple, rapid and simultaneous characterization and quantification of the polyphenolic fraction of extra-virgin olive oil from different PDOs (18 compounds in less than 7 min). To demonstrate the usefulness of this method, we have analyzed 16 samples of a Spanish PDO and nine other samples belonging to an Italian PDO (n = 5).RESULTS: In this way, it was possible to compare the phenolic profiles of the oils of different zones of the same PDO, as well as the phenolic profiles of Spanish and Italian extra-virgin olive oils. Univariate statistics were used for differentiating the oils produced in each PDO. Furthermore, the correlations among several of the phenolic compounds present in the extracts of olive oil and its sensorial properties were checked. decarboxylated oleuropein aglycon (DOA) (b) (peak 6) was the compound more related to the bitterness of the oils, Ac Pin (peak number 4) and the unidentified peak with tmig 4.025 min played an important role in the pungent taste of the oils, and these two latter compounds and the peak 13 seemed to be related to the fruitiness of the oils.CONCLUSIONS: The electrophoretic method described in the current work has the ability to detect and quantify simultaneously 18 phenolic compounds (belonging to five different families) in less than 7 min. This technique could improve the characterization of this polar fraction and determine the geographical origin of olive oils or detect possible 'PDO markers'. In fact, capillary electrophoresis coupled to statistical analysis enabled discrimination among olive oils belonging to two different PDOs considering eight phenolic compounds present in the extracts, and also identification of the phenolic compounds which could have more influence on several sensory attributes such as bitterness, pungency and fruitiness.