Fresh pork begins to deteriorate soon after slaughter as muscle tissue consumes its energy reserves. Researchers have now demonstrated that applying an electrostatic field (EF) during controlled freezing-point storage can slow this biochemical process. The treatment preserved more glycogen and adenosine triphosphate (ATP), limited lactate buildup, and altered the structure of soluble muscle proteins. It also influenced post-translational modifications (PTMs) on glycolytic enzymes, potentially offering a new method to maintain fresh pork quality during refrigerated transport and storage without freezing the meat.
Postmortem glycolysis is a major factor in meat quality loss, where glycogen is converted to lactate, causing pH to drop and leading to pale, soft, exudative meat with poor water-holding capacity. Conventional refrigeration slows this process, but storage near the freezing point offers better preservation, though it requires precise temperature control. Electrostatic fields have shown promise in improving water distribution and expanding the usable near-freezing temperature range, but their effects on metabolic pathways and enzyme regulation had not been thoroughly investigated.
Researchers from the Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, and the College of Food Science and Engineering, Ocean University of China, conducted a study published in Food Quality and Safety (DOI: 10.1093/fqsafe/fyag047). They compared pork muscle stored at 4 ± 0.5 °C, at −1 ± 0.5 °C, and at the same near-freezing temperature with a continuous 12-kV electrostatic field. The study tracked changes in energy metabolites, glycolytic enzymes, and sarcoplasmic protein structure over 120 hours postmortem.
The team collected longissimus thoracis et lumborum muscle from eight pig carcasses and measured glycogen, glucose, pyruvate, lactate, ATP, and Na⁺/K⁺-ATPase activity. They also analyzed phosphorylation and acetylation of lactate dehydrogenase (LDH), triosephosphate isomerase (TPI), and pyruvate kinase (PK). After 120 hours, electrostatic-field-treated pork had 17.5% less lactate than conventionally refrigerated samples, while glycogen and ATP consumption were reduced by 14.9% and 37.3%, respectively. The treated samples also retained more pyruvate and showed lower Na⁺/K⁺-ATPase activity. Early exposure promoted larger protein aggregates, but from 36 to 120 hours, proteins became smaller, more dispersed, and more ordered. Enzyme modifications changed over time, with the treatment generally reducing phosphorylation and increasing acetylation, consistent with slower glycolytic activity.
The authors suggest that the preservation effect is not just from lower temperature but from the EF influencing the molecular environment of glycolytic enzymes. The time-dependent protein changes—from initial unfolding to later ordering—may explain the reduced conversion of pyruvate to lactate and better energy retention. These findings provide a mechanistic basis for developing EF-assisted cold storage in fresh meat supply chains, potentially protecting water-holding capacity, texture, and appearance during processing and retail. The low-power 30-watt system also suggests energy efficiency, though commercial benefits were not directly tested.
Future research should validate the causal link between protein structural changes and enzyme PTMs, including molecular dynamics simulations. Larger studies should assess microbial safety, sensory quality, shelf life, equipment scale-up, and performance across different muscles and products before industrial adoption.
