NMR-Metabolomic Study on Monocultivar and Blend Salento EVOOs including Some from Secular Olive Trees

Abstract

The aim of the present work has been to characterize, by NMR-based metabolic profiling, extravirgin olive oils (EVOOs) from a subarea (Salento) of Apulia, leader EVOO producer among the Italian regions. According to the European Union (EU) definition, Protected Designation of Origin (PDO) products are mostly closely linked to the concept of terroir due to the place of origin, climate and local know-how. Moreover, the authenticity and traceability of several products such as olive oils with specific geographical origin require to be preserved by analytical methods. In this regard, about a hundred EVOO samples (monovarietal and blend samples, cultivars Ogliarola Salentina and Cellina di Nardò, basis of “Terra d’Otranto” PDO, campaign 2012-2013) were therefore analyzed by 1 H NMR spectroscopy and multivariate statistical analysis. Both unsupervised (PCA) and supervised (OPLS-DA) statistical analyses allowed differentiation of monocultivar oils and blends characterization. Other features such as the age of the trees (young, <100 years, and secular olive trees, >100 years) could also be investigated. Cellina samples showed a higher content of aldehydic and phenolic compounds, while Ogliarola samples were characterized by NMR signals in the range of δ H 6.5 - 5.6, which could be ascribed to higher carotenoids content. Higher polyphenols and polyunsaturated fatty acid content were also found in young over secular tree EVOOs.