Oxidative Modification, Structural Conformation, and Gel Properties of Pork Paste Protein Mediated by Oxygen...

The objective of this study was to investigate the effect of pork oxidation through modified atmosphere packaging (MAP) on gel characteristics of myofibrillar proteins (MP) during the heat-induced gelation process. The pork longissimus thoracis (LT) was treated by MAP at varying oxygen concentrations (0, 20, 40, 60, and 80% O₂) with a 5-day storage at 4 °C for the detection of MP oxidation and gel properties. The findings showed the rise of O₂ concentration resulted in a significant increase of carbonyl content, disulfide bond, and particle size, and a decrease of sulfhydryl content and MP solubility (p < 0.05). The gel textural properties and water retention ability were significantly improved in MAP treatments of 0-60% O₂ (p < 0.05), but deteriorated at 80% O₂ level. As the concentration of O₂ increased, there was a marked decrease in the α-helix content within the gel, accompanied by a simultaneous increase in β-sheet content (p < 0.05). Additionally, a judicious oxidation treatment (60% O₂ in MAP) proved beneficial for crafting dense and uniform gel networks. Our data suggest that the oxidation treatment of pork mediated by O₂ concentration in MAP is capable of reinforcing protein hydrophobic interaction and disulfide bond formation, thus contributing to the construction of superior gel structures and properties.