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Variability of 4-monomethylsterols and 4,4′-dimethylsterols in olive oil and their use as indicators of olive variety, ripening degree, and oil storage temperature

Lukic, Marina, Lukic, Igor, Sladonja, Barbara, Pilizota, Vlasta
Journal of agricultural and food chemistry 2015 v.63 no.22 pp. 5499-5508
discriminant analysis, flame ionization, gas chromatography-mass spectrometry, multivariate analysis, olive oil, olives, ripening, storage temperature
To investigate the variability of 4-monomethylsterols and 4,4'-dimethylsterols in olive oil as a result of variety, ripening, and storage temperature, 36 samples were subjected to gas chromatography with flame ionization detection (GC-FID) and with mass spectrometric detection (GC-MS), and results were processed by univariate and multivariate statistics. Relative amounts (percent) of β-amyrin, cycloartenol, and 24-methylenecycloartanol accounted for the most variation due to variety, while citrostadienol (percent) and 24-methylenecycloartanol (milligrams per 100 g) were strongly affected by ripening. Multivariate statistics differentiated olive oils regardless of storage conditions, which implied the possibility to use 4-monomethyl- and 4,4'-dimethylsterols as indicators of variety and ripening degree for fresh and stored oils. Absolute changes in 4-monomethyl- and 4,4'-dimethylsterols after storage were of a much smaller magnitude, meaning the investigated olive oils essentially retained health-beneficial features that derive from these compounds. Relative changes caused by storage were specific for each storage temperature and were useful in discriminating oils by linear discriminant analysis.