Effect of Heating Temperature on the Structure and Functional Properties of Tilapia Myosin

To explore the effect of heating temperature on myosin functional properties, this study systematically analyzed the correlation between its functional properties (solubility, turbidity, emulsifying activity, and flavor binding capacity) and structural changes of tilapia myosin at different temperatures (40~90 ℃). Results demonstrated that with increasing temperature, myosin solubility significantly decreased (51.91% reduction at 90 ℃ vs 40 ℃) (Pα-helix (5.44% decrease) and β-sheet (42.08% decrease) contents, alongside a 102.64% increase in random coils. This exposed internal hydrophobic groups (0.30% increase in surface hydrophobicity) and active sulfhydryl groups (10.23% increase), enhancing hydrophobic interactions and providing additional flavor-binding sites. However, weakened electrostatic repulsion reduced emulsifying activity. In the medium-temperature stage (50~60 ℃), the unfolding of myosin structure intensified, leading to a 19.59% increase in surface hydrophobicity. The exposed active sites of myosin enhanced flavor-binding capacity, reduced the solubility and increased emulsifying activity and turbidity. In the high-temperature phase (60~90 ℃), irreversible denaturation promoted dense aggregate formation via hydrophobic interactions and disulfide bonds, evidenced by increased β-sheet (19.85%) and β-turn (4.72%) contents. Aggregation led to turbidity increase (6.21% increase at 90 ℃ vs. 40 ℃) (P<0.05), reduced surface hydrophobicity (26.95% reduction), and diminished active sulfhydryl content (76.27% reduction). Although the network formed between myosin molecules enhanced the emulsifying activity (29.68% increase at 80 ℃ vs 60 ℃), it masked flavor-binding sites, decreasing flavor retention. The research results provided theoretical references for the regulation of heat treatment parameters in fish meat product processing.