ISHS Acta Horticulturae 586: IV International Symposium on Olive Growing
STUDY OF THE STEROLIC FRACTION OF SOME FREE CROSSBREEDING OLIVE CULTIVARS |
| Authors: | H. Fourati, M. Cossentini, M. Khlif |
| Keywords: | olive oil, unsaponifiable, varietal character, sterols. |
| Abstract:
In the present work, we have been interested in studying the unsaponifiable part, particularly the sterolic fraction, of oils extracted from 17 olive seeds cultivars obtained by a free crossbreeding. The aim is to study the influence of varietal character on the sterolic fraction. The gas chromatography preliminary analysis on capillary column showed an important variability among the oils extracted from these cultivars, in their fatty acid composition. The analysis of the sterols, silylated with trimethylsilytrifluoroacetamide (BSTFA), by gas chromatography on a capillary column indicated the presence of eight sterols. The quantitative study of this fraction revealed no significant difference in the percentage of sterols among all studied oils. There was a clear predominance of the  -sitosterol, which is a very interesting sterol from a biological view because it opposes the intestinal absorption of the cholesterol.
In fact, it exceeded 80% in all oil samples.
In addition to these eight sterols, we observed traces of two triterpenes alcohols: the erythrodiol and the uvaol.
These two compounds are usually used to detect refined grignons oil in the virgin olive oil. Despite the great fatty acids composition variability observed, no significant difference was detected on the sterolic composition of oils extracted from the studied cultivars. We can then conclude that the sterolic composition seems not to be a varietal character. | |
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