Mutagen formation in a model beef supernatant fraction. IV. Properties of the system.

Abstract

To identify the precursors and elucidate the reaction conditions that yield heterocyclic amine mutagens in cooked meat products and fish, we have used a supernatant 2 (S2) fraction prepared from H2O-homogenized lean round steak. Compounds (MW less than 500) in S2 are the sources of the microsomal-dependent, Salmonella TA 1538 mutagenic activity in open boiled (aqueous), 200 degrees C pressure-heated (aqueous), or 200 to 300 degrees C oven-baked (freeze-dried) homogenates. Combined incorporation-HPLC experiments show that they are also the precursors for frameshift mutagen formation in the outer surfaces of 200 degrees C griddle-fried ground beef. Maximal stimulations of boiled S2 mutagenic activity are given by 10 mM Trp, 2.5 mM creatine phosphate (CP), and synergistically by 10 mM Trp + 2.5 mM CP + 1.0 mM FeSO4 (a mixture abbreviated as S2*). Boiling S2 for 30 hr at the acidic optimum pH of 4.0----600 TA 1538 revertants (no additions) and 1,400 revertants (+CP), while S2*----24,000 revertants/10(8) bacteria/g of dry beef. By the criteria of HPLC, paper electrophoresis, and resistance of the active HPLC fractions to acid-nitrite inactivation, boiled S2 contains 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 3-amino-1-methyl-5H-pyrido[4,3-b]indole (Trp-P-2) and a minor amount of 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ). Boiling S2 with CP doubles the IQ, halves the Trp-P-2, produced traces of MeIQ, and generates an unknown nitrite-resistant mutagen. Boiled S2* contains these same four mutagens, but both the IQ and Trp-P-2 are increased and large amounts of Trp-P-1 also are generated. The identities of IQ, Trp-P-2, and Trp-P-1 were verified by purification and by light-absorption and mass spectra. Their increments in stimulated S2 indicate that Trp (or its degradation products) and CP (or its degradation products) are the beef juice precursors for the indole ring in Trp-P type mutagens and the NH2-imidazole ring in IQ-type mutagens, respectively. Aqueous (pressure) heating or oven-baking S2 for 2 hr at 200 degrees C greatly elevates its TA 1538 activity----45,000 revertants/10(8) bacteria/g of dry beef; dry heating at 300 degrees C----approximately 180,000 revertants/g of dry beef. Along with the increases in total TA 1538 activity at 200 to 300 degrees C, the number of mutagens formed from the less than 500 MW S2 precursors also multiplies.(ABSTRACT TRUNCATED AT 400 WORDS)

Mutagenic Activity of Heterocyclic Amines in Cooked Foods

“…Incorporation of the dried supernatant fraction into meat shows that it contains the precursors for mutagen formation because it increases the mutagenic activity of fried ground beef. Boiling the beef supernatant results in the formation of 2-amino-3-methylimidazo [4,5-f] quinoline (LQ); 3-amino-1-methyl-5Hpyrido [4,3-b]indole (Trp-P-2), and a small amount of 2-amino-3,4-dimethylimi- dry heating at 300°C gave 190,000 revertants/g of beef (12). Once the soluble supernatant precursors are concentrated to a freeze-dried powder, aqueous conditions are not essential for heterocyclic amine mutagen formation at ordinary cooking temperatures.…”

Isolation of the carcinogen IQ from fried egg patties

“…From our results one could assume, however, that the mutagenic activity we have observed (Bjeldanes et al, 1982b) under more reasonable cooking conditions is, at least in part, due to the compound IQ. The precursors of IQ-like compounds have been suggested (Yoshida and Fukuhara, 1982;Jagerstad et al, 1984;Taylor et al, 1985) as being creatine or creatinine in the presence of other amino acids and sugars. Our results comparing fried egg whites with egg yolks clearly implicate components found in the yolk as the precursors to the mutagens detected (Bjeldanes et al, 1982c).…”

Utilization of Asian spices as a mitigation strategy to control heterocyclic aromatic amines in charcoal grilled lamb patties

“…In meat products cooked at temperatures above 150°C, some harmful compounds are produced due to reactions between creatinine, amino acids, and sugars; these compounds are called heterocyclic aromatic amines (HAAs) (John & Beedanagari, 2014). Researchers have proposed many ways to control HAAs in cooked meat products, either using some modified cooking technologies, such as the use of microwave cooking (Taylor, Fultz, & Knize, 1986), or using some additives which have antioxidant potential (Balogh, Gray, Gomaa, & Booren, 2000) as a preventive strategy, but none of the strategies have been effective in inhibiting the heterocyclic amines in processed meat (Wong, Cheng, & Wang, 2012). Based on different studies and the pathways to generate HAAs, (Jiang & Xiong, 2016) if oxidation caused by free radicals could be reduced, the production of HAAs could be controlled in cooked meat.…”