Methylamino acids as indices in meat products

Summary A method is suggested for determining the 3-methylhistidine and N′-methyllysine content in meat and meat products using an ion exchange chromatography technique. 3-methylhistidine tires showed less variation within a sample than titres of N′-methyllysine. Concentrations of both 3-methylhistidine and N′-methyllysine in beef, lamb, pork and whale hydrolysates are given. In beef and lamb, the 3-methylhistidine concentrations have a mean value 6–0 (±0.7) mg/gN. the concentrations in pork varied between 5 and 56 mg/g N, an increase in concentration being related to an increase in age, whilst those of whalemeat were consistently high (° 300 mg/gN), A dipeptide of 3-methylhistidine and β-alanine, as found in whalemeat extracts, appears to be present in pork and can readily be removed from both pork and whale by a prior washing procedure. the levels of the residual, protein-bound 3-methylhistidine are then similar to those found in beef and lamb. Interspecies variation in N′-methyllysine is less marked. 3-methylhistidine and N′-methyllysine were absent from the non-meat proteins analysed. The similar interspecies value for the 3-methylhistidine bound to actin and myosin is tentatively suggested as an index of meat content in meat products.