Effect of Dietary Tocopherol on the Oxidative Stability of Turkey Meat

Abstract

The effects of dietary concentrations of dl-α-tocopheryl acetate and storage atmospheres on the oxidative stability of uncooked turkey carcass tissues were investigated. Eight hundred, one-day-old Nicholas white female turkey poults were raised to 16 weeks of age, randomly divided into 4 dietary groups for 3 weeks and assigned one of four pelletized diets containing either: A) 1.63 IU dl-α-tocopheryl acetate/kg of feed (Week 16 to 18); B) 1.63 IU (Week 16 to 17), 275 IU (Week 18); C) 55 IU (Week 16 to 18); or D) 275 IU (Week 16 to 18). All turkeys were processed at 19 weeks. Turkey breasts, thighs, skin, and subcutaneous fat and composites made up of these three tissues were evaluated for tocopherol levels shortly after processing (0 time) and TBA (2-thiobarbituric acid) numbers following refrigerated and frozen storage under N2 or air atmospheres. Composites were also evaluated by gas chromatographic headspace mediods at 0, 1, and 3 months of frozen storage.Tissue tocopherol levels and TBA numbers were significantly influenced by dietary tocopherol concentrations. As dietary levels increased, there were corresponding increases in tocopherol deposition for breast, thigh, and composite but not for skin and fat. Treatment (TMT) D turkey composites had mean tocopherol levels 3 to 3.3 times larger than TMT A tissues. Tocopherol levels were 100 to 600% higher in all treatments for thigh meat than breast or skin and fat. Overall TBA numbers were significantly affected by treatment and storage time but not storage atmosphere. Treatments B, C, and D composites, breasts, and thighs had TBA values significantly lower than TMT A. Furthermore, tocopherol tissue levels and TBA numbers were significantly correlated to the relative headspace volatile concentrations from heated turkey meat composites.It was concluded that tocopherol supplemented turkey diets are effective in reducing lipid oxidation during storage. Furthermore, headspace gas chromatography appears to be a potentially useful tool for determining oxidation in meat tissues.