Abstract
Olive oil industry generates huge amounts of by-products that are discarded and can be a serious environmental problem. In this study, the antioxidant activity of olive mill wastewater (OMWW), and olive pomace (OP) extracts (at different concentrations) with soy lecithin, on the thermal oxidative stability of sunflower oil (SO) were determined. The results generally showed that the higher the extract concentration added to SO, the higher the thermal stability of SO. OMWW and OP extracts had similar antioxidant activity in linoleic acid emulsion (87.59% and 97.74%). Trolox equivalent antioxidant capacity (TEAC) of extracts ranged between 6.7-27.1 mu M. When extracts with lecithin were added to SO, the induction periods (IP) and protective factors of SO were higher. In addition, the extracts were more effective when added together with lecithin. OMWW extract was more efficient in lowering the conjugated diene (CD) content in SO samples than the OP extract during the thermal oxidation test at 180 degrees C. SO enriched with OMWW extract and lecithin, had lower p-anisidine values, higher tocopherol content and higher IP than SO enriched with butylated hydroxytoluene (BHT) at the end of 40 h.