F. Angerosa et al., CARBON STABLE ISOTOPES AND OLIVE OIL ADULTERATION WITH POMACE OIL, Journal of agricultural and food chemistry, 45(8), 1997, pp. 3044-3048
Adulteration of olive oils can be detected by comparison of the C-13/C
-12 ratios as obtained subsequently by high-resolution gas chromatogra
phy (HRGC) and isotope ratio mass spectrometry (IRMS). In delta(13)C v
alues determined for the aliphatic alcoholic fraction of pomace oil, t
he adulterant was significantly more negative than those of virgin and
refined olive oils. Quantitative analysis of isoprenoids and methylst
erols isolated from each grade of olive oil supports the decreasingly
negative values of C-13/C-12 ratios for the better grades of olive oil
. These results have turned out to be a good tool for detecting adulte
ration of olive oil with the cheaper pomace olive oil, even down to a
5% level.