Utilization of molecular distillation for determining the effects of some minor compounds on the quality and frying stability of olive pomace oil

The objective of this study was to determine the effects of some minor components such as squalene and mono- and diglycerides (MDG) on the frying stability of olive pomace oil. Refined olive pomace oil was distilled using a falling film type short-path distillation unit at 230 °C under a pressure of 0.02 mbar to remove minor components. Distilled olive pomace oil was introduced with approximately 10,000 mg/kg of squalene and 2.5% of MDG. Fryings were performed 8 times/day at 180 °C for 3 min. Whole frying procedure proceeded for 5 days. Total polar compounds, polymerized triglycerides (PTG), free fatty acids, viscosity, color index, p-anisidine value, smoke point, fatty acid composition and iodine values of the oils were monitored. Results indicated that all criteria except smoke point and iodine value increased in all fractions during fryings. The lowest total polar compound was obtained in distilled olive pomace oil while PTG was the lowest in the MDG added fraction. Lower increases in viscosity and color indexes were recorded in squalene incorporated samples. It was observed that squalene and MDG were not effective on the oxidation rate of unsaturated fatty acids during frying.