It can be noticed that the samples of soybean oil presented a small variation among the peroxide values until the 14 day of storage. Figure 3c shows that, at the end of storage period, the rosemary extract increased the protection at 44 %, when compared to the soybean oil without additives. Besides, it is observed that the rosemary extract, for the corn oil (Fig. 3b), acted as a good antioxidant, protecting the oil with a protection factor of 60 %. The protection factor was also verified for the antioxidant TBHQ at the concentration of 100 mg kg-1. In the samples of sunflower oil, both rosemary extract and TBHQ were efficient in controlling the formation of peroxide; however,