Proton Nuclear Magnetic Resonance (1H NMR) was employed to study monovarietal commercial Spanish extra-virgin olive oils (EVOO) (Arbequina, Arroniz, Cornicabra, Hojiblanca and Picual). Each sample was analyzed by a standard pulse and by an experiment suppressing the main lipid signals, enabling the detection of signals of minor components. The aim was to determine the possibilities of both 1H NMR approaches to characterize EVOO composition, focusing on acyl groups, squalene, sterols, triterpene acids/esters, fatty alcohols, wax esters and phenols (lignans, tyrosol, hydroxytyrosol, oleocanthal, oleacein, oleokoronal, oleomissional, ligstrodials and oleuropeindials), and to determine hydrolysis and oxidation levels. The signal assignments (in deuterated chloroform) are thoroughly described, identifying for the first time those of the protons of esters of phytol and of geranylgeraniol. Correct signal assignment is fundamental for obtaining sound results when interpreting statistical data from metabolomic studies of EVOO composition and adulteration, making it possible to differentiate and classify oils.
... and Δ-5-campesterol from Larodan (Malm?, Sweeden); ursolic acid and ursolic acid methyl ester
from Extrasynthese (Genay, France); Δ-5-avenasterol from Chemfaces (Hubei, PRC);
hydroxytyrosol from Seprox Biotech (Madrid, Spain); apigenin from Biopurify (Chengdu, PRC ...
