IMPORVING OF VEGETABLE OILS STABILITY BY USING SOME NATURAL ANTIOXIDANTS PREPARATIONS

Sunflower oil (Antioxidant free) was treated with black seed and lettuce oil preparations at concentration of 0.1,0.3 and 0.5% , to study the improving stability of sunflower oil toward oxidation and rancidity at ambient , and thermal process at 120 ̊C for 18 hours. Radical scavenging activity DPPH% results indicated increased the ability of scavenging activity for black seed oil preparation compared to lettuce oil preparation 95.62 and 88.02 % and total phenolic compound contents ranged from 649.79 and 356.73mg/g gallic acid respectively . While results of HPLC indicated ellagic , benzoic and e-vanillic were higher in black seed oil preparation compared with e-vanillic , benzoic and catechol in lettuce oil preparation respectively. Obtained data proved that acid , peroxide and thiobarbituric acid (TBA) values that sunflower oil treated with black seed oil were higher than the other treated with lettuce oil preparation after thermal process. Black seed oil preparation caused the highest oxidative stability (highest induction period) 7 and 6 hours before and after thermal process . The results indicated that the 0.5% black seed oil preparation before and after thermal process and 0.5% and 0.1% from lettuce oil preparation regestied the more efficiency before and after thermal process respectively.