Comparison of antioxidative and synergistic effects of rosemary extract with α-tocopherol, ascorbyl palmitate and citric acid in sunflower oil

The antioxidative activities of four natural antioxidants: rosemary extract (ROS.CON), α-tocopherol (TOC), ascorbyl palmitate (AP) and citric acid (CA) were studied in sunflower oil stored at 60° C. Among them, rosemary extract (ROS.CON) exhibited the best antioxidative activity, as determined by peroxide and anisidine value measurements. α-Tocopherol showed a prooxidative effect on stability of sunflower oil at tested conditions. The synergistic effects of α-tocopherol (TOC), ascorbyl palmitate (AP) and citric acid (CA) on rosemary extract (ROS.CON) were investigated. When combined with citric acid and especially ascorbyl palmitate, the rosemary extract showed an additive antioxidative effect, while by mixture with α-tocopherol a negative synergism was observed.