STABLE CARBON-ISOTOPE RATIOS (C-13 C-12) OF OLIVE OIL COMPONENTS

A study was carried out relating carbon isotope discrimination (delta C-13) for the whole oil and some of its classes of compounds of four Italian olive varieties collected at six different stages of ripening in the period October-January 1991-1992. The delta C-13 value ranges found were as follows: whole oil, -27.18 to -28.57; sterols, -25.18 to -26.21; long-chain alcohols, -26.80 to -28.40; glycerol, -28.07 to -30.33. The major conclusions were that (a) most of the oil components appeared to be strictly Of C3 biosynthetic origin, (b) the ripening stage of the fruit did not affect the delta C-13 Values, and (c) the delta C-13 values of oil samples and the related classes of substances are significantly different. The implication is the delta C-13 values could be used in determining the purity and origin of olive oils.