Improvement of pale, soft, and exudative (PSE)-like chicken breast protein is urgently needed, to reduce the economic losses induced by its downgraded processing quality. The pH-shifting treatment increases the emulsifying properties of the myofibrillar protein (MP) of PSE-like meat, but the emulsion stability under various environmental conditions has yet to be explored. The creaming index under 60 and 80 °C decreased from 20.1% to 28.9%–16.1% and 26.7%, respective, indicating a higher stability against heating. pH-shifting significantly increased the stability of the emulsion, particularly at pH 7.0 and 7.5. Also, the pH-shifted emulsion could more effectively resist instability brought by freeze-thaw cycles. However, at lower salt concentrations, the stability of the pH-shifted emulsion was poor. Throughout the 48-h storage period at 4 °C, the pH-shifted group reached stability faster than the control, and the turbiscan index values were stabilized at 1.8 and 4.7, respectively. Overall, pH-shifting could improve the emulsion stability of PSE-like MP against heating, pH altering, salt content changing, freezing-thawing, and storage.
An unresolved problem in the field of food protein is the poor dispersibility of pale, soft, exudative (PSE)-like meat protein. This study aimed to verify the structural and functional robustness of myosin. Two different models, namely, PSE-induced whole meat model and pH shifting plus temperature holding of protein solution model, were developed. A novel combination of pH shifting (from 5.6 to 7.0) and low speed shearing (400 rpm) treatment decreased myosin turbidity by 9.6% and 36.5%, respectively. After readjusting the pH to 7.0, z-average size decreased from 289.0 nm to 1563.6 nm–274.0 nm and 333.3 nm, respectively. The experimental groups exhibited excellent solubility like the normal group. Scanning electron microscopy revealed that large myosin clusters and aggregates decreased. The improvement in PSE myosin stability increased the absolute ζ-potential value from −13.1 mV to −15.5 mV under treatment. Raman analysis revealed that the increase in protein function was not only because of surface charge states induced by pH shifting but also because of conformation recovery as evidenced by the increase in α-helix content. Results indicated that pH shifting and proper low shearing could fulfill the robustness of myosin function by recovering conformation and improving solubility.
危险品化学品经营许可证（带存储）