THE HYDROCARBON FRACTION OF VIRGIN OLIVE OIL AND CHANGES RESULTING FROM REFINING

In numerous Spanish virgin olive oils, 6,10-dimethyl-1-undecene, vario us sesquiterpenes, the series of n-alkanes from C14 to C35, n-8-heptad ecene and squalene are the only less volatile components detected by g as chromatography in the hydrocarbon fraction. In oils from olives of the Arbequine variety, a series of n-9-alkenes has also been found. In refined oils, notable features are the absence of the most volatile c ompounds and the appearance of other hydrocarbons produced during the refining process. Among these, n-alkanes, alkadienes (mainly n-hexacos adiene), stigmasta-3,5-diene, isomerization products of squalene, isop renoidal polyolefins coming from hydroxy derivatives of squalene and s teroidal hydrocarbons derived from 24-methylene cycloartanol were iden tified. Physical refining produces larger amounts of degradation produ cts and greater losses of n-alkanes than chemical processing. Squalene is the major hydrocarbon component in all oils, both virgin and refin ed. The ranges of concentration for the different hydrocarbons found i n Spanish virgin olive oils are presented.