Comparison of the Frying Performance of High Oleic Oils Subjected to Discontinuous and Prolonged Thermal Treatment

Frying is a popular practice because of its unique sensory characteristics and low cost. The high temperature reached with this cooking method alters molecules present in the oil. The deterioration of the oil depends primarily on its chemical composition. The aim of this study was to evaluate the thermal stability of high oleic sunflower oil (HOSO), sunflower oil (SO) and mixed oil (MIX) during deep frying of French fries. Octanoic acid and unsaturated fatty acid (UFA)/saturated fatty acid (SFA) ratio showed a good correlation with total polar compounds (TPC) for all frying samples analyzed. HOSO and MIX were characterized by reduced levels of thermal degradation, while SO resulted in the highest values of oxidation products (highest TPC values). SO was also the oil more retained by the food matrix, whereas MIX was the least absorbed. HOSO and MIX, having a high oleic acid content (77.58 and 59.92 %, respectively) and a low linoleic acid content (13.42 and 25.70 %, respectively), showed the best characteristics for the frying process.