Evolution of phenols and pigments in extra virgin olive oil from irrigated super-intensive orchard

Phenolic compounds have a high importance in olive oil because of their effect on shelf life and sensory properties. This study reports on the HPLC profiles of the phenolic compounds of virgin olive oils obtained from Arbequina olives from the harvesting in a super-intensive orchard under a linear irrigation system. In addition, phenolic content, carotenoid and chlorophyllic pigments, and oxidative stability were analyzed. Total phenol content and 3,4-DHPEA-EDA increased up to a maximum throughout the ripening process. The simple phenols tyrosol and hydroxytyrosol acetate increased throughout the ripening process, however, there was not found a clear trend in hydroxytyrosol content. Minor constituents such as vanillic acid and p-coumaric acid increased up to a maximum and then decreased, since vanillin decreased progressively throughout the time of harvest. 3,4-DHPEA-EDA and lignans were present in considerable amounts in the studied samples, while oleuropein aglycone was present in a low amount. Total phenol content and oil stability followed the same trend throughout the study, so a very good correlation was established between them. Total secoiridoids and, specifically, 3,4-DHPEA-EDA seemed to be responsible for oil stability. The pigment content decreased during ripening, and not a positive correlation was found between pigments and oil stability. Practical applications: The results can be used to determine the best time for harvesting in order to obtain olive oils with different phenols and pigment contents. This is important for sensory characteristics of the olive oils and also for olive oil stability.