PSV-29 Changes in the PSE and DFD porcine muscle proteome during autolysis

Abstract

Abstract Despite reducing of pale, soft, exudative (PSE) pork share, its amount is 45% in Russia and 65% in Belarus of the total. Dark, firm, dry (DFD) pork occurrence increases to 20% in Russia and 30% in Belarus. Protein changes in normal (NOR), PSE and (DFD) pork muscle during 5 days ageing were studied. Were found differences in their protein profiles and potential protein markers of such raw materials were identified. Mainly in range 600–1000 Da and up to 450 Da. Analysis of the peptide composition showed two myosin light chain isoforms (MLC) (Mw/pI): MLC-like protein — 21.8/5.00 and phosphorylated MLC f -21.0/4.90, in the sample. One of which is fast, the other is slow MLC isoform. Increase in the number of fragments was noted of such proteins as pyruvatekinase, α-enolase, muscle creatine phosphokinase and GPDH, adenylatekinase, αB-crystallin. A correlation between muscle proteins breakdown (the troponin group/troponin family) and the characteristics of meat was found. In NOR samples, troponin I decomposed quite clearly. The most obvious autolysis marker is the appearance and increase of three additional fragments of fast skeletal muscle troponin T, which differ in molecular weight and pI. According to the tryptic peptides mass spectra, the C- and N-molecule terminal parts peptides are no longer detected sequentially. Moreover, in DFD samples, they are most significantly split into shorter peptides. Appearance of short N-terminal GPDH 21 kDa fragment on the 5th day of autolysis is PSE specific marker. Totally 12, 14 and 18 specific peptides were identified in chilled and 18, 32 and 38 on 5th day of autolysis in PSE, NOR and DFD pork respectively. DFD meat can be considered a source of natural specific low-molecular peptides, specifically to produce meat products with functional properties. (Research was supported by the Russian Science Foundation, project 16-16-10073)