Polyunsaturated fatty acids are highly susceptible to oxidation which greatly reduces their nutritional value and their organoleptic properties as well as flavor and quality of the foods that are fortified with them. Commonly used antioxidants such as tocopherols have generally limited antioxidant activity for highly polyunsaturated edible oils and the amounts of more effective synthetic antioxidants such as TBHQ are regulated to limits of less than 200 ppm. More recently introduced natural antioxidants based on rosemary extracts have been reported to have better antioxidant efficacy and stability when used in edible oils such as vegetable and marine oils. Also lecithin has been reported in the past to be a positive synergist to antioxidants in fats and oils when used combination with both natural and synthetic antioxidants.
We evaluated natural antioxidants rosemary extracts in combination with several phospholipids to produce an antioxidant blend with a superior antioxidant activity when compared to commercial extracts. This presentation will include results on antioxidant activity of various common antioxidant ingredients including tocopherols, ascorbyl palmitate, rosemary extracts and several lecithins in fish oil. Oxidation tests, conducted in an OSI instrument at 80 C and 110 C, confirmed that rosemary extracts-based phospholipid antioxidant blends were more effective antioxidants than tocopherols-based antioxidant blends for anchovy fish oil. Tocopherols stopped been effective at approximately 1000 ppm. On the other hand, the efficacy of rosemary-phospholipid antioxidant blend developed in this work increased proportionally with the concentration at levels higher than 5000 ppm.