Enhancing Lipid Oxidative Stability of Cooked-Chilled Lamb Meat through Dietary Rosemary Diterpenes

A dietary rosemary extract (DRE) containing carnosic acid and carnosol at 1:1 (w/w) for enhancing the lipid oxidative stability in cooked-chilled lamb meat, is evaluated. Three diets for fattening lambs are tested: i) a cereal-based concentrate (C-diet); ii) the C-diet plus 600 mg vitamin E per kg feed (E-diet); and iii) the C-diet plus 600 mg rosemary diterpenes per kg feed (R-diet). Griddled-chilled lamb patties are kept at 4 °C and lighting for 2 days, simulating catering conditions. Diterpenes have a lower deposition rate than vitamin E in lamb muscle and are completely degraded during cooking. DRE is thus less effective than dietary vitamin E in enhancing the oxidative stability of the patties. After 2-day storage, the R-diet shows lower (p < 0.01) peroxide values and thiobarbituric acid reactive substances than the C-diet, while, in contrast to the E-diet, it does not inhibit (p > 0.05) the formation of cholesterol oxidation products. The R-diet increases (p < 0.05) the proportion of polyunsaturated fatty acids and decreases (p < 0.05) the n-6/n-3 ratio. These findings suggest antioxidant protection by dietary bioactive compounds beyond the direct radical scavenging activity that is able to stabilize lipids during the meat shelf-life. Practical Applications: Cooked-chilled meat lipids strongly oxidize in ready-to-eat dishes kept in retailing conditions, which may negatively affect their levels of polyunsaturated fatty acids (PUFA), cholesterol oxidation products (COP), and other lipid oxidation products. Dietary rosemary diterpenes can be used as a clean alternative to feed additives to enhance the oxidative stability of cooked-chilled meat. Improved health and antioxidant status of the animal might be able to reduce oxidative spoilage during meat shelf-life. Diterpenes provide lesser antioxidant protection than dietary vitamin E but may improve the PUFA content, with positive implications for the nutritional quality of lamb fat. The use of dietary antioxidants with different properties may contribute to improving the efficacy of animal feeds to improve meat quality.