Effects of ultrasound-assisted tumbling on the quality and protein oxidative modification of spiced beef.

The aim of this study was to investigate the effects of ultrasound-assisted tumbling (UT) with different ultrasound powers (frequency 20 kHz, powers of 0, 300 W, 450 W and 600 W) on the quality of spiced beef as explained from the perspective of the changes of muscle fibers and myofibrillar proteins (MPs). The results showed that pH value, tenderness and yield rate of UT groups were all apparently improved compared with the single tumbling group (P < 0.05). Ultrasound-assisted tumbling treatment could loosen muscle fiber structure supported by scanning electron microscopy (SEM) result, and the increased myofibrillar fragmentation index (MFI) value (P < 0.05). Additionally, an upward trend was observed in protein oxidation degree with the rise of ultrasound power level (P < 0.05), while the difference between groups in MPs solubility was not significant (P > 0.05). Above all, ultrasound-assisted tumbling treatment could effectively improve the quality of spiced beef by exacerbating the modifications in muscle fiber structure and MPs.