Determination of free amino acids of porcine serum responsible for the meat quality by 1H NMR and HPLC analyses
The objective of this study was to determine alternative meat-quality factors in porcine sera. We investigated serum metabolites from high pH group (HpHG) and low pH group (LpHG) on the basis of pH 24 h of post-mortem muscle (pH24h). The pH24h correlated well with the water holding capacity (WHC) of porcine meat, whereas a strongly negative correlation was observed between pH24h and serum sodium level. For serum metabolites obtained by 1H NMR spectra and PicoTagTM based HPLC, principal components analysis showed clear differences between the HpHG and the LpHG. The 1H NMR spectra of serum metabolites at 600 MHz showed that free amino acids such as alanine, leucine, phenylalanine, and valine were qualitatively higher in the HpHG than in the LpHG. The relative abundance of three amino acids was quantitatively verified by HPLC: Phenylalanine and valine (P<0.01) and leucine (P<0.05). These free amino acids in porcine serum are considered as suitable indicators of meat quality in Berskshire pigs.
Key words: Porcine meat quality, muscle pH, principal components analysis, serum metabolites, free amino acids.