Influence of Dietary Fat and Vitamin E on Shelf Life of Ground Broiler Breast and Thigh Meat
Type of Degreedissertation
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A series of experiments were conducted to determine the effects of dietary fat sources and vitamin E supplementation on shelf life of ground broiler breast and thigh meat. The first experiment evaluated the influence of dietary fat sources and inclusion levels on ground breast and thigh meat shelf life stored under refrigerated conditions (2°C) with either oxygen permeable or impermeable packaging. Corn oil resulted in higher raw ground thigh meat lipid oxidation rate than lard. Microbial counts and lipid oxidation increased with refrigerated storage of raw ground meat and was higher in thigh than in breast muscle. Oxygen impermeable packaging appeared to reduce lipid oxidation. Experiment two evaluated the influence of dietary fat sources on ground breast and thigh meat shelf life stored under frozen conditions (-18°C) for 3 and 6 months with either permeable or impermeable packaging. Oxidative deterioration was nearly 3-fold higher in ground thigh than in ground breast meat. At 3 months of storage, higher levels of oxidation occurred with corn oil than lard; with higher fat inclusion level and with oxygen permeable packaging. Ground meat in oxygen impermeable packaging showed lower lipid oxidation than oxygen permeable film. An improvement in oxidative stability and a reduction of bacterial growth were seen in ground meat samples stored in impermeable packaging at 3 months of storage. Two final experiments investigated the effects of vitamin E supplementation on ground breast and thigh meat (either raw or cooked) shelf life under refrigerated and frozen storage. Data from both experiments confirmed that dietary vitamin E supplementation at high levels (>120 IU/kg) significantly reduced the rate of lipid oxidation in cooked ground breast and thigh meat. Microbial and oxidative changes that occur during refrigerated and frozen storage of ground and cooked broiler meat were positively influenced by dietary vitamin E supplementation. Significant effects were achieved with thigh meat (especially cooked) but not with breast meat. Lipid oxidation increased during refrigerated storage on both raw and cooked ground meat. Unsaturated lipid content of poultry meat may justify the need for different packaging types or diet supplementation with antioxidants to optimize the quality and shelf life of ground poultry meat.