Olive oil extraction by supercritical carbondioxide and comprasion of biophenolic and triglyceride composition of the extracts with conventional extracted ones

Olives collected from the local olive oil producers situated almost in all olive producing geographic regions of Turkey were extracted with supercritical carbondioxide (SCE) and the oils obtained have been investigated with respect to trigliserid acid and biophenolics composition. Samples from oils extracted from the same olives by the local oil producers via the conventional methods and the results obtained from SCE and the conventional methods were compared. While the oleic acid contents were lower in SCE oils when compared with the conventionally extracted oils, the reverse was true for palmitic, stearic, and linoleic acid contents. Iodine value measurements has shown that there were slight decreases in unsaturated acid contents of SCE oils compared to the corresponding conventionally extracted oils due to the relative changes in the contents of these four major acids of the olive oils. The highest linoleic acid contents were %12.9, %12.4 and %12.0 in SCE oils obtained from Burhaniye/Taylieli olives, Izmir/Bornova olives and Mut olives (Ayvalik type) while the corresponding values for the conventionally extracted oils were %9.5, %9.7, and %8.7 mg/kg. SCE oils had oleic acid contents less than the corresponding values from conventionally extracted oils with a ratio varying between 8 to 14 percent. The biophenolic contents of SCE oils were many folds higher than the corresponding values obtained from the conventionally extracted oils. Three of the SCE oils, namely Izmir/Bornova, Hatay/Altinozu and Mut (Gemlik type) had the highest total biophenolic contents of 117.0, 115.6, and 102.3 mg/kg, respectively. Key Words: Olive, SCE, biophenolics, fatty acid compositions