Inhibitory effect of carbohydrates on the formation of mutagens in fried beef patties.

Beef patties were prepared by mixing minced meat with water and either glucose (1, 2 or 4%), lactose (1, 2 or 4%) or powdered milk (2, 4 or 8%) before frying. In another experiment, minced meat was mixed with starch from golden bread crumbs (3%) or potatoes (4%), with and without glucose (1, 2 or 4%). The patties (100 g) were fried for 3 min at 150 or 180 degrees C in a double-sided fryer. The mutagenic activity in the crust was determined using the Ames test. With the addition of glucose or lactose (1-4%), the mutagenic activity was inhibited by 34-76%. A similar inhibition of the mutagenic activity was obtained with powdered milk. However, starch from golden bread crumbs or potatoes caused only a slight (not significant) decrease in mutagenic activity whereas adding both starch and glucose to the beef patties inhibited mutagenic activity by up to 54%.

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.