SUPPLEMENTATION OF BROILER DIETS WITH ALL-RAC-ALPHA- OR A MIXTURE OF NATURAL SOURCE RRR-ALPHA-,GAMMA-,DELTA-TOCOPHERYL ACETATE .2. EFFECT ON THE OXIDATIVE STABILITY OF RAW AND PRECOOKED BROILER MEAT-PRODUCTS

Oxidative stability of muscle from broilers fed I) basal feed; 2) basa l feed supplemented with 100 mg of a mixture of natural source RRR-alp ha-, gamma-, delta-tocopheryl acetate/kg feed; 3) basal feed supplemen ted with 100 mg of synthetic all-rac-alpha-tocopheryl acetate/kg feed; 4) basal feed supplemented with 500 mg of a mixture of natural source RRR-alpha-, gamma-, delta-tocopheryl acetate/kg feed; or 5) basal fee d supplemented with 500 mg of synthetic all-rac-alpha-tocopheryl aceta te/kg feed, was evaluated during chill and freezer storage by determin ation of thiobarbituric acid reactive substances (TEARS). The oxidativ e stability of precooked muscle was investigated in a chill storage ex periment and in a model system with accelerated oxidation. The basal f eed contained a standard added amount of 46 mg all-rac-alpha-tocophery l acetate/kg feed. Furthermore, the basal feed had a high natural cont ent of vitamin E, resulting in a dietary vitamin E level in the contro l feed of 72 mg alpha-tocopherol and 69 mg gamma-tocopherol, a level t hat provided a reasonable oxidative stability for the meat. In spite o f this, raising the dietary vitamin E level resulted in improved oxida tive stability of broiler muscle during storage. Supplementation of br oiler feed with 100 mg all-rac-alpha-tocopheryl acetate/kg, resulting in a total alpha-tocopherol content of 198 mg/kg feed, was found to be sufficient to improve stability of precooked broiler breast and preco oked thigh muscles during chill storage, and further to ensure stabili ty of raw meat during chill and freezer storage. The mixture of natura l source RRR-alpha-, gamma-, delta-tocopherol was less effective in pr otecting broiler muscles than the synthetic all-rac-alpha-tocopherol, when compared on a weight basis.