Polar and non-polar heterocyclic amines in cooked fish and meat products and their corresponding pan residues

Abstract

Fourteen cooked dishes with their corresponding pan residues were analysed for polar and non-polar heterocyclic amines using HPLC. The choice of foods, including beef, pork, poultry, game, fish, egg and sausages, was based on an investigation of an elderly population in Stockholm participating in an analytical epidemiological case-control study on cancer risks after intake of heterocyclic amines. The food items were prepared using normal household cooking practices, and to reflect the wide range of surface browning of the cooked dishes that would be encountered in this population, four cooking temperatures were used in the range 150–225°C. For all food samples, the total amount of heterocyclic amines formed at 150°C was less than 1 ng/g cooked product, and at 175°C less than 2 ng/g. The highest concentrations of heterocyclic amines were detected in fillet of pork, reindeer meat and chicken breast fried at 200 and 225°C and their corresponding pan residues. The total sum of 2-amino-3,8-dimethylimidazo-[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline and 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine was about 1 μg per 100 g portion (including pan residues) for reindeer meat and chicken breast, and between 1.9 and 6.3 μg per 100-g portion for fillet of pork. PhIP was the most abundant heterocyclic amine, identified in 73 of 84 samples, and the highest concentration of PhIP, 32.0 ng/g, was found in the pan residue from fillet of pork cooked at 225°C. The non-polar heterocyclic amines 3-amino-1,4-dimethyl-5 H-pyrido[4,3- b]indole and 3-amino-1-methyl-5 H-pyrido[4,3- b]indole were detected in the range of 0.5–7.4 ng/g in most foods cooked at 225°C, and also in meat sauce prepared at 200 and 175°C. The other heterocyclic amines tested for: 2-amino-3-methylimidazo-[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-6-methyl-pyrido-[1,2- a:3′,2′- d]-imidazole and 2-aminodipyrido-[1,2- a:3′,2′- d]imidazole, were present only at very low or non-detectable levels. The low recoveries of the amino-α-carbolines 2-amino-9 H-pyrido[2,3- b]indole and 2-amino-3-methyl-9 H-pyrido[2,3- b]indole made it impossible to quantify them. However, the co-mutagenic substances 1-methyl-9 H-pyrido-[3,4- b]indole and 9 H-pyrido[3,4- b]indole were detected at levels of about 1–30 ng/g in most of the dishes cooked at 200 and 225°C.