Insight into the effect of ultrasound treatment on the rheological properties of myofibrillar proteins based on the changes in their tertiary structure

This was the first study to perform correlation analysis to determine the relationships between tertiary structural and rheological properties of the myofibrillar proteins (MPs) under ultrasound treatment (UT, frequency 20 kHz, power 500 W, intensity 30 %) for 0, 2, 4, 6, 8, and 10 min. The objectives of this study were to 1) characterize the changes of the small and large deformation rheological properties of MPs based on the tertiary structural changes; 2) determine relationships of rheological property, tertiary structural changes, and UT time. The results showed that UT could enhance the structural rigidity and the resistance of the system to permanent deformation observed in rheological tests. Besides, UT could unfold MPs, expose more hydrophobic amino acid residues to increase the surface hydrophobicity (S0-BPB), destroy disulfide bonds to increase the content of reactive sulfhydryl content (R-SH). The correlation analysis showed that the rheological properties of MPs could be improved by UT with a longer treatment time (0–10 min), while inevitably and significantly changing the tertiary structure of MPs (p < 0.05). These findings suggested that UT might be effective in the food-processing industry to change the structure of proteins and improve rheological properties.