How multi-frequency ultrasonication treatment affects the conformational performances, oxidation, emulsification, and...

This study concentrated on the influence of multi-frequency ultrasonication (under varied frequency modes) on the structural, oxidation, emulsification, and gel characteristics of beef myofibrillar protein (MP). The results showed that total thiol groups and surface hydrophobicity were increased following ultrasonication, whereas reduction in carbonyl content was observed. Compared to the control, dual frequency ultrasound (25/28 kHz) increased the emulsifying activity and stability, and as well the ζ-potential of beef MP (to 7.49 m²/g, 18.35 min, and 8.25 mW respectively), but reduced the particle size. Reference to color, beef MP gel exhibited significantly higher L^⁎ and whiteness values, a stable a^⁎ value, and lower b^⁎ value. Besides, water holding capacity of gel and cooking loss rate were increased to 66.72 % and 7.71 % under dual frequency ultrasound (25/28 kHz), respectively. After dual frequency (25/28 kHz) ultrasound, the α-helix in beef MP decreased to 10 %, while the irregular coil content increased by 12 %. At the same ultrasound frequency, the MP gel displayed a notably dense and uniform surface appearance. Correlation analysis and the proposed mechanism of ultrasonication on the oxidation characteristics of beef MP and the improvement of emulsification gel properties indicated that sonication impaired the carbonyl content and altered the spatial conformation of beef MP, causing the collapse of disulfide bonds to form thiol groups inside beef MP. Multi-frequency ultrasound treatment, compared to single-frequency ultrasound, offers a broader range of effects, deeper penetration, and stronger synergistic effects, allowing it to act more uniformly on beef MP. Altogether, these findings provide both theoretical insight and practical guidance for using multi-frequency ultrasonication to develop functional meat products with improved texture, emulsification, and oxidative stability. This aligns with growing consumer demands for high-quality, health-oriented, and safe protein-based foods.