Use of Olive Waste Cake Extract as a Natural Antioxidant for Improving the Stability of Heated Sunflower Oil

Olive waste cake (OWC) is underestimated as an agricultural waste. In this work, OWC extract were obtained by ethanol. Antioxidant efficacy of ethanolic OWC extract at levels of 100, 200, 400 and 600 ppm were studied. Samples of sunflower oil mixed with OWC extract were intermittent heated at 180±5°C for 4 hr / day, for 5 consecutive days and has been assayed for stabilization of sunflower oil against control (antioxidant free sample) and 200 ppm Butylated hydroxi toluene (BHT) containing sample. Results exhibited the efficiency of OWC at level up 100 ppm in reducing the changes in the physical properties of sun flower oil during the heating at 180±5°C, whereas changes were lower than that of the control and the sample containing 200 ppm, also the OWC at the same mentioned levels reduced the changes in the chemical properties of sunflower oil. With regarding to the oxidative stability of sunflower oil, the OWC treated sample (with the same levels) revealed good oxidative stability parameters peroxide value (PV), Thiobarbituric acid (TBA) value and Rancimat induction period) as compared with the other samples, also the calculated oxidative stability parameters (protection factor and calculated oxidative stability at ambient temperature i.e. Induction, Expired and Shelf-life months) were higher than that of the control, BHT treated samples, while the sample treated with 100 ppm OWC revealed lower physical and chemical quality properties than BHT treated sample. It was concluded that olive waste cake extract at 200 ppm and higher levels can effectively protect sunflower oil during the heating at 180 ± 5°C.