Identification and classification of olive oils by high‐resolution13C nuclear magnetic resonance

Unsaponifiable matter from 19 olive and olive pomace oils were studied by high‐resolution13C nuclear magnetic resonance spectroscopy. Their spectra showed characteristic peaks that corresponded to molecular substructures rather than the individual constituents present in the unsaponifiable matter. The presence of squalene and other hydrocarbons, sterols and triterpenic alcohols, in addition to other groups of minor compounds, were observed. Based on the analysis of these spectra, it was possible to distinguish among different grades of olive oils by using stepwise discriminant analysis. This direct method of analysis is suggested to be used in artificial neural networks to define oil identity and quality.