The proteome of goat meat exudate: Temporal proteomics as a new way to uncover the underlying mechanisms of meat tenderization

This study applied shotgun proteomics to investigate the temporal changes in goat meat exudate and elucidate the biochemical mechanisms underlying postmortem aging. Exudates were collected from vacuum packaged goat Longissimus thoracis muscles at 24, 48 and 72 h postmortem. A total of 823 proteins were identified and quantified, of which 188 were differentially abundant: n = 60 between 24 h vs. 48 h, n = 56 between 48 h vs. 72 h and n = 168 between 24 h vs. 72 h. Comparative analyses revealed distinct temporal release patterns, with catalytic and ATP-metabolic proteins predominating early postmortem (17%), structural and contraction-related proteins peaking between 48 h and 72 h (39%), and binding, transport, and calcium homeostasis proteins (27%), as well as extracellular matrix (ECM) and matrisome components (14%), accumulating later. Chaperones including heat shock proteins and proteolytic and related enzymes were consistently released from 24 h to 72 h, but in lower percentages (5% and 4%, respectively). Overlap analysis identified 14 core proteins including FLNC, TNNI2, TNNC2, PDLIM7, TMOD4, MYOZ1, MYBPC1, MYOM2 (muscle contraction and structure), DYSF, EIF4G2, PPARGC1A (binding, transport and calcium homeostasis), DCN, OGN, and IGFALS (matrisome and ECM associated proteins), shared across all time points, which mapped to five significantly enriched pathways, primarily myofibril assembly and muscle system processes. These findings provide the first comprehensive proteomic profile of goat meat exudate, demonstrating its potential as a non-invasive source for monitoring postmortem biochemical changes and meat tenderization dynamics, ultimately offering insights to improve meat quality.