Fresh pork quality during storage and transport may get a boost from a novel application of electrostatic fields, according to research published in the journal Food Quality and Safety. The study, conducted by 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, demonstrates that combining an electrostatic field with controlled freezing-point storage can slow the biochemical processes that lead to meat deterioration, preserving quality attributes such as color, moisture, and texture.
The research addresses a common problem in the meat industry: postmortem glycolysis. After slaughter, muscle tissue continues to metabolize glycogen, converting it into lactate. This accumulation of lactate causes pH to drop, which can lead to pale, soft, and exudative meat with poor water-holding capacity. Conventional refrigeration slows this process but is not always sufficient, especially during long distribution chains. Storage near the freezing point offers better preservation but requires precise temperature control. Electrostatic fields have previously been explored for improving water distribution and extending the temperature range for near-freezing storage, but their effects on metabolic pathways and enzyme regulation were not well understood.
In the study, pork muscle samples were stored under three conditions: conventional refrigeration at 4 ± 0.5 °C, controlled freezing-point storage at −1 ± 0.5 °C, and the same near-freezing conditions with a continuous 12-kilovolt electrostatic field. The researchers tracked changes in energy metabolites, glycolytic enzymes, and sarcoplasmic protein structure over 120 hours postmortem. They measured glycogen, glucose, pyruvate, lactate, adenosine triphosphate (ATP), and sodium-potassium adenosine triphosphatase (Na⁺/K⁺-ATPase) activity. They also analyzed post-translational modifications (PTMs) on key glycolytic enzymes: lactate dehydrogenase (LDH), triosephosphate isomerase (TPI), and pyruvate kinase (PK).
The results were striking. After 120 hours, pork treated with the electrostatic field contained 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. Additionally, the electrostatic field altered the structure of sarcoplasmic proteins. Early in storage, proteins formed larger aggregates, but from 36 to 120 hours, they became smaller, more dispersed, and more ordered. This suggests that the treatment not only slows down glycolysis but also changes the molecular environment in which enzymes operate.
Post-translational modifications on glycolytic enzymes also changed with storage time. The treatment tended to reduce phosphorylation and increase acetylation, which is consistent with slower glycolytic activity. Correlation analysis linked the protein structural shifts with enzyme modification levels, indicating that the electrostatic field influences both the conformation and the regulatory switches of these enzymes.
The authors emphasize that the preservation effect is not simply a result of colder temperatures. Instead, the electrostatic field appears to modulate the molecular environment, altering protein structure and enzyme activity in a time-dependent manner. This provides a mechanistic explanation for the slower conversion of pyruvate into lactate and better retention of cellular energy.
The findings offer a foundation for developing electrostatic-field-assisted cold storage for fresh meat supply chains. By slowing pH decline and conserving ATP, this technology could help protect water-holding capacity, texture, appearance, and overall saleable quality during processing, transport, and retail display. The system uses only 30 watts, suggesting potential for energy-efficient preservation, although commercial benefits were not directly tested in this experiment.
Future research should validate the causal link between protein structural changes and enzyme PTMs, potentially using molecular dynamics simulations. Larger studies are needed to assess microbial safety, sensory quality, shelf life, equipment scale-up, temperature fluctuations, operating costs, and performance across different muscles and meat products before industrial adoption. The study was supported by the National Key Research and Development Program of China and was published with DOI: 10.1093/fqsafe/fyag047.
