226 Proteomic and Metabolomic Profiles are Associated with Fresh Pork Loin Quality Phenotypes

Abstract

Abstract The objective was to define proteomic and metabolomic profiles associated with premium and poor-quality pork. Fresh pork loins (n=100) were aged 12 to 14 d postmortem before quality evaluation. Chops with a star probe values less than 4.5 kg, and a Hunter L score less than 47 were categorized as Premium (n=10). Chops with star probe values greater than 5.7 kg and Hunter L greater than 49.7 were categorized as Poor (n=10). Proteins soluble in low ionic strength buffer (50 mM Tris-HCl pH 8.5 and 1 mM EDTA) were extracted, digested with trypsin, and labeled with 11-plex isobaric TMT labels. Peptides were introduced to the Q-Exactive Hybrid Quadrupole-Orbitrap Mass Spectrometer and identified and quantified with Proteome Discoverer. Data were normalized to the total ion count from each run, Log2 transformed, and median normalization was performed. Only proteins identified in at least one-half of the samples containing at least two unique peptides were included in the analysis. Non-targeted metabolomic analyses were conducted on extracts (80% methanol) of each sample. Separation was conducted with a TG-5MS column (Thermo Scientific, 30m x 0.25mm x 0.25mm). Masses between 50-620 m/z were scanned at four scans/sec after electron impact ionization operating at 70eV. All data were analyzed in R 4.1.1 using the limma package with a false discovery rate of 0.05. Poor chops contained more sugars, including glucose, glucose-6-phosphate, fructose, and galactose. Premium chops had more amino acids, including leucine, isoleucine, serine, and methionine. Proteins/peptides in greater abundance in the soluble fraction in the Premium chops (n=24 proteins) included titin, filamin, phosphoglycerate mutase, AMP deaminase, heat shock protein 27, and calcium transporting ATPase. Proteins/peptides in greater proportion in the Poor chops (n=12 proteins) included annexin, adenylate kinase, and Maillard deglycase. The results demonstrate that distinct molecular phenotypes are associated with variation in fresh pork quality.