The present work was carried out on some new sesame seeds varieties namely: Toshaka 1, Shandaweel 3 and Giza 32 in an attempt to evaluate the utilization of sesame oil as a source of natural antioxidants. Antioxidative effect of isolated natural antioxidants on the oxidative stability of sunflower oil during heating up to 18 hours was evaluated. The acid value of sunflower oil was increased during heating up to 9 hours and then decreased. The oil samples treated with antioxidants had the least amount of free fatty acids, after heating up to 9 hours, which is due to a very low degree of hydrolysis in oil as affected by addition of antioxidants. As heating time was increased, peroxide values increased up to 9 hours, and then decreased. The peroxide values were also less in sunflower oil treated with antioxidants, which was an indication that antioxidants decreased the oxidation of sunflower oil.
The addition of antioxidants to sunflower oil was very effective since the TBA values after 18 hours of heating were significantly less than the values of the oil without adding antioxidants.
Conjugated diene and triene formation in oil samples increased with heating time up to 18 hours. Blending of sunflower oil with antioxidants, resulted in a significant decrease in conjugated diene and triene values, compared with control samples. In general it could be concluded that sunflower oil containing natural antioxidants had a much greater oxidative stability than oils without adding antioxidants. Addition of natural antioxidants could increase shelf life of oils. In addition, natural antioxidants are safe and impart health benefits to the consumer