In-pack combination of ultrasonication and sous-vide accelerates goat meat tenderization: gene expression and biochemical changes during early post-mortem storage.

Meat tenderness is key to consumer acceptance but is challenged by goat meat's leanness and high connective tissue content. A promising solution is the in-pack combination of ultrasonication (US) and sous-vide (SV) technologies to enhance tenderness while ensuring product safety. This study investigates the individual and combined effects of US and SV on biochemical and molecular changes in goat meat during the first 48 h post-mortem, focusing on glycolysis, proteolysis, apoptosis, and water retention, compared to an untreated control (C). At 48 h post-mortem, US + SV resulted in the fastest pH decrease (p < 0.05), correlating with glycogen and ATP depletion and lactate accumulation, indicating accelerated glycolysis and hastened rigor mortis. Both US and SV individually enhanced sarcoplasmic and myofibrillar protein degradation, as shown by increased solubility and myofibrillar fragment index (MFI), and their combination had a synergistic effect on proteolysis. Only US + SV promoted collagen degradation (p < 0.05). US alone accelerated ATP degradation, whereas SV had no significant effect (p > 0.05), suggesting minimal impact on energy metabolism. SV enhanced US-driven proteolysis, likely by stabilizing proteolytic enzyme activity to function effectively in catalyzing the breakdown of proteins. Gene expression analysis confirmed that US + SV and US induced early apoptosis and proteolysis, particularly within the first 12 h, which corresponded to lower Warner-Bratzler Shear Force (WBSF) values, indicating improved meat tenderness. Despite higher weight loss, US + SV improved cooking loss compared to C (p < 0.05). These findings suggest that US + SV accelerates proteolysis and enhances meat tenderness, providing valuable insights for the meat industry in optimizing post-mortem processing techniques.