Proteomic analysis of the quality deterioration of pork: a comparative study of fresh and six-month frozen storage

This study investigates the quality deterioration of pork during six-month frozen storage using polarized light microscopy and tandem mass tag (TMT)-based quantitative proteomics. Ice recrystallization analysis revealed the formation of larger ice crystals over time, which mechanically disrupted muscle structure and reduced water-holding capacity. Proteomic analysis identified 180 Differentially Expressed Proteins (DEPs) between fresh and frozen pork, with significant alterations in proteins related to structural integrity, energy metabolism, and stress response. Key metabolic pathways, including glycolysis, fatty acid degradation, and oxidative phosphorylation, were notably suppressed in frozen samples. Protein-protein interaction network analysis highlighted central regulatory nodes such as ATP5F1A and CAT, which were downregulated in frozen pork. Moreover, potential freeze-responsive biomarkers such as CA2, ALDH2, S100A1, and TRIM63 were identified, indicating metabolic impairment and muscle contraction dysfunction in frozen meat. These findings offer molecular-level insights into freeze-induced damage mechanisms and suggest potential biomarkers for evaluating frozen pork quality.