Using of olive leaves extract for increasing the stability of refined soybean oil

Olive leaves are considered a waste during olive oil extraction and appear as a good source of natural antioxidant because it contains a high percent of phenolic compounds. This work aims to evaluate the effect of olive leaves extract (OLE) on acceleration of lipid oxidation in refined soybean oil. The olive leaves extract was added to refined soybean oil with different concentrations (5, 10, 50, 100 and 200 ppm). The butylated hydroxytoluene (BHT) at concentration 200 ppm was used as a control. The refined soybean oil (SBO) samples treated with OLE and BHT which exposed to accelerated oxidation in the dark conditions in an oven at (70±3°C) for 72 hours. The olive leaves extract showed a high antioxidant activity like synthetic antioxidant (BHT) at 200 ppm by measuring the peroxide values (PV) and thiobarbituric acid value (TBA) during accelerated storage. The olive leaves extract approximately has the same strong antioxidant activity of the BHT when is used as natural antioxidant in soybean oil at 200 ppm.