Impact of pre-rigor ultrasonication on beef quality: A mechanistic perspective involving glycolytic and mitochondrial metabolism at the early postmortem

This study investigated the impacts of pre-rigor ultrasonication (0, US300, and US600 W for 30 min with the frequency of 20 kHz) on pH variation and quality attributes of beef muscle, along with the underlying mechanisms related to glycolytic and mitochondrial metabolism at the early postmortem. Results demonstrated that both pre-rigor US treatments, particularly US600, accelerated early postmortem pH decline as well as improved meat color redness, water-holding capacity, and tenderness during subsequent aging. Mechanistically, US600 potentiated pH decline through dual pathways involving direct upregulation of sarcoplasmic calcium and glycolytic enzyme activities, coupled with the disruption of mitochondrial structure and function. However, US300 accelerated glycolytic flux and pH decline only through regulating mitochondrial metabolism without directly affecting glycolytic enzyme activities. Moreover, the reasons for the improved beef quality were integrated from both pH-dependent and independent pathways. This work elucidated how postmortem energy metabolism and the resulting beef quality responded to the variations in pre-rigor US, informing the rational design of potential US technology for consistent high-quality beef production.