Effect of Electric Field-Assisted Controlled Freezing Point Storage on the Quality and Key Glycolytic Enzymes of Fresh Pork

This study aimed to investigate the effect of electric field-assisted controlled freezing point storage on postmortem pork quality and the activities of key glycolytic enzymes. Pork longissimus dorsi muscles were assigned to different storage conditions: conventional refrigeration storage (4 ℃), controlled freezing point storage at -1.0 ℃, 4 kV electric field-assisted controlled freezing point storage (-1 ℃ + 4 kV), and 12 kV electric field-assisted controlled freezing point storage (-1 ℃ + 12 kV). The quality parameters, activities of key glycolytic enzymes, and phosphorylation and acetylation levels of sarcoplasmic proteins were analyzed. The results showed that the -1 ℃ + 12 kV group exhibited a significantly higher pH at 72 h postmortem compared with the 4 ℃ and -1 ℃ groups, but significantly lower cooking loss at 6-36 h and significantly lower shear force at 120 h compared with the 4 ℃, -1 ℃, and -1 ℃ + 4 kV groups (P < 0.05). During 36-120 h postmortem, the activities of glycogen phosphorylase, lactate dehydrogenase, and pyruvate kinase exhibited decreasing trends in the 4 ℃, -1 ℃, and -1 ℃ + 12 kV groups. Notably, the three enzyme activities remained lower in the -1 ℃ + 12 kV group than in the 4 ℃ and -1 ℃ groups during 36-120 h postmortem. At 72 h postmortem, the phosphorylation and acetylation levels of sarcoplasmic proteins were markedly lower in the -1 ℃ + 12 kV group than in the 4 ℃ and -1 ℃ groups. In conclusion, compared with the 4 ℃ and -1 ℃ + 4 kV groups, the -1 ℃ + 12 kV group exhibited significantly delayed pH decline, decreased cooking loss, and improved tenderness. Furthermore, 12 kV electric field treatment appeared to influence the activities of key glycolytic enzymes by modulating their post-translational modifications, thereby contributing to the preservation of meat quality.