Mechanism of Oxidation-induced Functionality Changes of Myofibrillar Protein

Texture-related characteristics (tenderness, firmness, juiciness, etc.) are among the most important factors that define "quality" and consumer acceptance of meat and meat products. These quality parameters are ultimately attributed to muscle proteins, especially their chemical properties and functionality. Recent studies have produced concrete evidence that links quality deterioration in muscle foods during processing and storage to oxidative changes in proteins, suggesting that controlling protein oxidation may be of great importance to ensuring meat product quality. Although some progress has been achieved in the effort to establish the role of protein oxidation in fresh and processed meats, the mechanism of muscle protein oxidation and its impact on protein functionality remain poorly understood. The objectives of this research are to characterize protein oxidation under meat processing conditions, and to elucidate the relationship between protein oxidation and texture-related functional properties of muscle foods. Myofibrillar proteins isolated from pork shoulder muscle will be subjected to three oxidizing systems commonly encountered in meats: a hydroxyl radical-generating system (Fe/H2O/ascorbate); oxidizing lipids (linolenic); and a metmyoglobin oxidizing system. Oxidized proteins will be characterized for structural changes by differential scanning calorimetry, fluorometry, FTIR; for the formation of protein adducts and derivatives by HPLC; and for aggregation patterns by electron microscopy and electrophoresis. Oxidized proteins will be further analyzed for gelation and emulsification properties in relation to the above physicochemical changes. An elucidation and improved understanding of the mechanism ofmyofibrillar protein oxidation would help the design of antioxidative/oxidative strategies for optimizing the quality and storage stability of fresh and processed muscle foods, thereby contributing to the sustainability of the U.S. agriculture and the food industry.