Abstract：This study aimed to investigate the effects of different cations (Na+, K+ and Li+) at a concentration of 0.6 mol/L and pH levels (7.0, 6.0 and 5.0) on the frozen storage stability of myofibrillar protein (MP) solution. The results demonstrated that both cation species and pH significantly influenced the degree of MP denaturation during freezing. At the same pH level, K+ addition resulted in the most pronounced aggregation of MP after freezing, while Na+ and Li+ had similar effects on MP aggregation. At pH 7.0 in the presence of K+, the solubility of MP was the lowest after freezing, with a marked decrease from 83.08% to 43.38%. Concurrently, the presence of K+ resulted in significantly higher surface hydrophobicity and larger particle size in MP compared to the other cations (P < 0.05). Among the three ions, K+ had the most substantial impact on MP structure after freezing, manifested by a conformational shift from α-helix to β-turn and random coil, along with reduced maximum fluorescence intensity of intrinsic fluorescence spectroscopy. Furthermore, K+ treatment led to the highest degree of MP oxidation after freezing. Decreasing pH enhanced the detrimental effects of freezing on MP, with the effect being particularly pronounced in the presence of K+. In conclusion, different cations and pH levels significantly affected the physicochemical properties of MP following freezing; notably, K+ promoted MP denaturation and oxidation.
2026, Vol. 40 
