Effect of resting temperature on the aggregation and gel properties of pork myosin with sodium bicarbonate

Abstract

This study investigated the influence of resting temperature (8 h at 4, 20, 40, 60, and 80 °C) on the thermal aggregation behavior and gelation properties of pork myosin solution with 40 mM sodium bicarbonate. The results showed that from 4 °C to 40 °C, turbidity and particle size decreased progressively, indicating enhanced solubility and molecular dispersion before rising again above 40 °C, signaling aggregation onset. Concurrently, surface hydrophobicity and active sulfhydryl content increased to maxima at 40 °C (P < 0.05), reflecting controlled unfolding and exposure of buried domains. Functionally, gelation from 4 °C to 40 °C significantly improved (P < 0.05) water retention, textural parameters, and gel strength, while whiteness declined slightly consistent with formation of a fine, uniform, and highly hydrated network. At 80 °C, severe irreversible denaturation occurred, manifesting as network fragmentation, reduced gel strength, diminished hardness and elasticity, and compromised water retention. Meanwhile, T_2b and T₂₁ relaxation times decreased monotonically up to 40 °C, and P₂₁ peaked area at 40 °C collectively affirming that 40 °C represents the thermodynamic optimum for sodium bicarbonate-assisted gelation of pork myosin. Collectively, these findings indicate that 40 °C is the critical thermal condition under which sodium bicarbonate most effectively controlled aggregation, and formed good structure with dark color in pork myosin gels.