Effects of precursor composition and water on the formation of heterocyclic amines in meat model systems

Model systems based on pressed meat from ox, pork and chicken were used to study the formation of carcinogenic/mutagenic heterocyclic amines (HAs). The composition of precursors (free amino acids, creatine and glucose) was examined and samples were heated in test-tubes under wet and dry conditions at 175 and 200°C for 30 min. Several HAs were detected, and the formation of DMIP (2-amino-1,6-dimethylimidazo[4,5-b]-pyridine), TMIP (2-amino-1,5,6-trimethyl-imidazo[4,5-b]-pyridine), IFP (2-amino-1,6-dimethylfuro[3,2-e]imidazo[4,5-b]-pyridine) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine) was found to be favoured by dry heating conditions. Highest amounts of PhIP and IFP were detected in heated meat juice from chicken breast, while more MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]-quinoxaline) was found in heated meat juices from roast beef and pork chop. Norharman (9H-pyrido[3,4-b]-indole) and Harman (1-methyl-9H-pyrido[3,4-b]-indole) were also detected at high levels.