Effect of commercial marinades on the mutagenic activity, sensory quality and amount of heterocyclic amines in chicken grilled under different conditions.

The effect of processing conditions on the mutagenic activity and sensory quality of everyday food was studied by investigating grilled chicken samples seasoned with four different marinades and grilled at temperatures of about 110, 170 and 220 degrees C. The amounts of the heterocyclic amines 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 were determined only in samples grilled at 220 degrees C, using a gas chromatography-mass spectrometry technique with negative-ion chemical ionization. Sensory quality was determined using the extended ranking test method and the mutagenic activity using the Ames Salmonella assay. At 220 degrees C one of the marinades decreased the mutagenic activity in the chicken samples compared with the unseasoned control or samples treated with the other marinades. Great variations, without any clear correlation with mutagenicity, were observed in the amounts of heterocyclic amines between chicken samples treated with the same or different marinades. At the grilling temperatures of 170 degrees C and 110 degrees C the mutagenic activities of the chicken samples were lower or they were non-mutagenic. There was no correlation between mutagenic activity and sensory quality of the products. The samples with high mutagenic activity were ranked to be as good as the samples with lower or no mutagenicity. The results show that it is possible to prepare grilled products with reduced mutagenicity without compromising their sensory quality. It was also evident that marinades can have a reducing effect on the mutagenicity of grilled chicken. Variation observed in the amounts of heterocyclic amines between equivalent products makes it difficult to estimate their concentration in everyday foods.

Screening of heat-processed Finnish foods for the mutagens 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.

The concentrations of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and DiMeIQx (i.e. the sum of 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline and 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline) were determined as their 3,5-bis(trifluoromethyl)benzyl bromide derivatives in commercial heat-processed daily Finnish foods using the gas chromatography-mass spectrometry technique with negative chemical ionization. With this technique it was possible to detect picogram quantities of halogenated aminoimidazoazaarene (AIA) derivatives. The mutagenic activities of the food samples were tested using the Ames Salmonella assay. The mutagenicities and amounts of the AIA compounds analysed varied considerably in the food samples. All the flame-broiled fish samples and the majority of the grilled pork and chicken samples were positive in the test; of all the food samples tested fish samples had the highest mutagenic activity. Industrially produced meat patties were non-mutagenic. The amounts of MeIQx, DiMeIQx and PhIP in grilled products that exhibited mutagenic activity varied in the range 0.04 to 0.4, 0.03 to 0.2 and 0.5 to 3.8 ng per g cooked food, respectively. Some of the highly mutagenic flame-broiled fish samples contained only PhIP, the amount of which varied from 0.5 to 5.5 ng per g fish. One of the samples also contained a small amount of MeIQx. None of the non-mutagenic meat patties contained detectable amounts of MeIQx, DiMeIQx or PhIP. In this screening study evaluation of the occurrence of AIA compounds was carried out in a relatively wide range of commercial heat-processed Finnish foods. Considerable differences between equivalent products from different manufacturers were found in many cases. This variation indicates that industrial processing of food has a marked effect on the mutagenic activity of the product.

Sources of mutagenicity in cooked Finnish foods.

The mutagenic activities of the alkaline fractions derived from various heat-processed, ready-made meat, fish and poultry foods were studied using the Salmonella mutagenicity assay with strain TA98 and S-9 mix to provide information about the mutagenicity of everyday Finnish foods. The majority of the food samples tested were mutagenic. The mutagenic activities of various commercial ready-made products. Mutagenicity varied remarkably between different samples. The cooking temperature clearly affected the mutagenicities of fried or reheated food samples, mutagenicity increasing with increasing temperature. The results indicate that the main sources of cooked-food mutagens in everyday Finnish foods are grilled and broiled products and foods fried at restaurants and at home. By comparison, commercial ready-made fried foods are only a minor source of mutagenicity. Variations between equivalent food samples indicated that heat processing has a marked effect on the mutagenic activity of the product, which might therefore be reduced by modifying the cooking process.