Effects of ultrasound-assisted modification during freeze-thaw cycle on gel properties and conformation of myosin in EGCG-modified systems: Roles of ionic strength and ultrasound power

This study investigated effects of ultrasound power and ionic strength on conformation and gel properties of chicken myosin under freeze-thaw (FT) cycle in EGCG-mediated system. Ultrasound significantly increased solubility, α -helix content, and surface hydrophobicity, while reduced turbidity, particle size, sulfhydryl content, and intrinsic fluorescence ( P  < 0.05), indicating that mechanical forces induced by ultrasound promoted structural unfolding, which increased disulfide bonding and hydrophobic interactions, thereby enhancing myosin-myosin and myosin-EGCG interactions. Ultrasound significantly increased β -sheet, viscosity, gel strength, and ratio of immobile water, while reduced α-helix content and thawing loss of frozen myosin gel ( P  < 0.05). SEM, LF-NMR, and MRI analyses indicated that ultrasound facilitated formation of a compact network structure of myosin gel after FT cycle, significantly increasing water-holding capacity (WHC) of frozen myosin gel. WHC of myosin gel at 0.6 M NaCI was better than that at 0.3 M NaCI, resulting in higher gel strength and thawing loss.