DIFFERENTIAL SCANNING CALORIMETRY DETECTION OF HIGH OLEIC SUNFLOWER OIL AS AN ADULTERANT IN EXTRA-VIRGIN OLIVE OIL

Differential scanning calorimetry (DSC) was employed to detect high oleic sunflower oil (HOSo) as an adulterant in extra-virgin olive oil (EVOo) by means of cooling and heating thermograms. Addition of HOSo did not significantly alter cooling profiles of EVOo except for onset temperature of crystallization, which was significantly shifted toward lower temperature at 40% of adulterant addition. At the same percentage of adulteration, the heating profile of EVOo was significantly changed as the major endotherm broadened and the minor event became smaller and less evident. Cooling thermograms of pure oils and their admixtures were deconvoluted into three constituent exothermic peaks in an attempt to detect addition of HOSo at levels lower than 40%. Thermal properties of the two lower-temperature exotherms (area percentage, offset temperature and range of transition) were significantly changed at >= 20% of HOSo substitution, suggesting that DSC can be employed to detect this oil as an EVOo adulterant.