Effect of dietary rosemary and α-tocopheryl acetate on the oxidative stability of raw and cooked pork following oxidized linseed oil administration

The effect of a 2% dietary administration to pigs of oxidized linseed oil (targeted level of 150 mEq. O2/kg oil after heating at 50 °C and exposure to air for 3–4 days following addition of 10 ppm CuSO4), either or not in combination with antioxidants, on the oxidative stability of raw and cooked pork during illuminated chill storage was assessed. The antioxidant treatments were: 40 ppm α-tocopheryl acetate, 40 ppm rosemary extract, 40 ppm rosemary extract + 2 ppm gallic acid, and 40 ppm α-tocopheryl acetate + 40 ppm rosemary extract. A total of 20 ppm of α-tocopheryl acetate (ATA) was added to all diets in order to meet the physiological requirement of the animals. The antioxidant treatments did not exert any effect on colour and protein oxidation. Lipid oxidation was only decreased by dietary ATA when comparing the ATA supplemented groups combined versus a control treatment group for raw but not for cooked meat. This was due to a higher content of α-tocopherol in the meat and subcutaneous fat. The lipid oxidation results suggested a lack of antioxidant effect for the rosemary extract. No evidence for a synergistic effect of the antioxidant combinations was observed.