Effects of meat composition and cooking conditions on the formation of mutagenic imidazoquinoxalines (MeIQx and its methyl derivatives).

In recent years it has been shown that certain methyl derivatives of 3H-imidazo[4,5-f]quinoxaline-2-amine are responsible for a major part of the mutagenicity formed during frying, broiling or baking of meat, and also formed in the preparation of meat extracts. The present study describes the precursors of these compounds and their formation with participation of Maillard or nonenzymatic browning reactions. The formation of these IQ-type mutagens was shown to occur when model systems of creatin(in)e, reducing monosaccharides, and certain amino acids were heated at 128 degrees C for 2 hr. In meat experiments, the mutagenicity was found to be significantly correlated with the presence of creatin(in)e in the meat samples. The same conditions that are favorable for Maillard reactions, such as supply of starting materials, high temperature, and a suitable water concentration, also increased the yield of mutagenicity during cooking. Fats seemed to act as regulators of the amount of heat transferred into the product rather than as reactants in the formation of mutagenicity.