Contents of creatine, creatinine and carnosine in porcine muscles of different metabolic types.

Creatine, creatinine and carnosine have been analyzed by hydrophilic interaction chromatography (HILIC) in seven different pork muscles of different metabolic type (Semimembranosus, Biceps femoris, Gluteus maximus, Longissimus dorsi, Gluteus medius, Trapezius and Masseter). As reported in previous literature, carnosine contents are related with the type of metabolism, being higher in those muscles with glycolytic metabolism. Creatine and creatinine also showed significantly higher concentrations in glycolytic muscles such as Semimembranosus, Biceps femoris, Gluteus maximus and Longissimus dorsi. Masseter, a red oxidative muscle, was characterized by the lowest contents of creatine, creatinine and carnosine and, finally, Gluteus medius and Trapezius, both intermediate muscles, had also intermediate contents of these studied compounds. Finally, a correlation between initial content of creatine and creatinine formation after cooking has been verified using pure standards and two different metabolic type muscles, Longissimus dorsi and Masseter, obtaining slightly higher creatinine amounts in Longissimus dorsi, probably due to its higher initial creatine content and its lower pH.