EFFECT OF DIETARY ALPHA-TOCOPHEROL SUPPLEMENTATION AND GAMMA-IRRADIATION ON ALPHA-TOCOPHEROL RETENTION AND LIPID OXIDATION IN COOKED MINCEDCHICKEN

The effects of dietary alpha-tocopherol supplementation and gamma-irra diation on alpha-tocopherol retention and lipid oxidation in cooked mi nced chicken during refrigerated storage were studied. Minced breast a nd thigh meat from broilers fed diets supplemented with 100, 200 or 40 0 mg alpha-tocopheryl acetate/kg feed was irradiated at 2.5 or 4.0 kGy . Cooked irradiated and unirradiated meat was stored at 4 degrees C fo r 5 days. alpha-Tocopherol concentrations increased with increasing di etary supplementation. Concentrations decreased during storage, but re tention was not affected by irradiation. Lipid stability was determine d by measuring the formation of thiobarbituric acid-reacting substance s (TBARS) and cholesterol oxidation products (COPs) during storage. TB ARS and COPs increased during storage and were reduced by increasing l evels of dietary alpha-tocopheryl acetate supplementation. Irradiation accelerated TBARS formation during storage, but this was prevented by supplementation with 200 mg alpha-tocopheryl acetate/kg feed. Irradia tion tended to increase COPs during storage, although no consistent ef fects were observed. In general supplementation with over 400 mg alpha -tocopheryl acetate/kg feed may be required to control cholesterol oxi dation in minced chicken. The results suggest that, overall, irradiati on had little effect on lipid stability in alpha-tocopherol-supplement ed meat following cooking and storage. (C) 1998 Elsevier Science Ltd, All rights reserved.