Abstract: The effects of ultrasound treatment at different powers (20 kHz for 6 min; 0, 150, 300, 450 and 600 W) on the structure, physicochemical properties and emulsifying properties of pale, soft and exudative-like (PSE-like) chicken meat myofibrillar protein (MP) were investigated. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed no significant changes in the composition of MP after ultrasound treatments; however, the band intensities of myosin heavy chain and actin were significantly increased at ultrasonic power of 450 and 600 W (P < 0.05). The α-helix content, surface hydrophobicity and solubility of MP increased and the β-fold content decreased as the ultrasonic power increased to 450 W. The α-helix content, surface hydrophobicity and solubility of MP decreased at 600 W ultrasonic power, but they were still significantly higher than those of the control group (P < 0.05). With an increase in ultrasound power, the fluorescence intensity of MP increased, and the particle size and zeta potential of MP and MP emulsion decreased significantly (P < 0.05). At ultrasonic power of 600 W, the highest emulsification activity index (EAI) and emulsion stability index (ESI) of MP, and the lowest oil/water interfacial tension and Turbiscan stability index of MP emulsion were obtained, indicating the highest emulsion stability. The cold field emission scanning electron micrograph confirmed that the oil droplets of the emulsion were smaller and more uniform. In summary, ultrasonic treatment can change the structure and physicochemical properties of PSE-like chicken MP, in turn improving the emulsion stability.

Key words: pale, soft and exudative-like chicken; myofibrillar protein; ultrasound; structural properties; emulsifying properties