Effects of Rosemary Extracts on the Reduction of Heterocyclic Amines in Beef Patties

ABSTRACT:  The effects of rosmarinic acid and a rosemary antioxidant powder were evaluated on the reduction and mutagenicity of MeIQx, PhIP, and comutagens norharman and harman in beef patties fried at 375 °F for 5 min each side and 400 °F for 7.5 min each side. Both rosemary extracts were found to effectively decrease the formation and overall mutagenic activity of heterocyclic amines (HCAs) due to their antioxidative characteristics. At the lower temperature, rosmarinic acid was able to reduce MeIQx by up to 64% and PhIP by 48%, while rosemary powder reduced the formations of MeIQx up to 69% and PhIP up to 66%. The effects of the rosemary extracts were more dramatic when cooking temperature and time were increased, as rosmarinic acid was able to reduce MeIQx formation up to 70% and PhIP up to 64%; also, rosemary powder significantly reduced MeIQx up to 57% and PhIP up to 77%. The overall mutagenic activity was evaluated by the Ames Salmonella assay and both rosemary extracts were capable of reducing mutagenicity in beef patties at the higher cooking temperature of 400 °F. At 375 °F there was an insignificant trend of the rosemary extracts decreasing the number of Salmonella revertants. There was no significant inhibiting effect by any of the rosemary extracts on the formation of either norharman and harman as measured in this study.     

Inhibitory activity of Asian spices on heterocyclic amines formation in cooked beef patties

Heterocyclic amines (HCAs) are mutagenic compounds formed when foods are cooked at high temperatures. Numerous reports have shown that natural antioxidants from spices, fruits, chocolate, and tea can inhibit formation. In this study, we evaluated HCA formation in the presence of 5 of Asian spices: galangal (Alpinia galangal), fingerroot (Boesenbergia pandurata), turmeric (Curcuma longa), cumin (Cuminum cyminum), and coriander seeds (Coriandrum sativum). HCA levels were compared to patties containing rosemary (Rosmarinus officinalis), of which the inhibitory effect is well documented. Inhibition of HCA formation by the spices was evaluated in beef patties cooked at 204 °C (400 °F) for 10 min. All spices were mixed into patties at 0.2% before cooking, and HCAs levels were measured in the final product. All patties, including the control, contained 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline (MeIQx) and 2-amino-1-methyl -6-phenylimidazo [4,5-b]pyridine (PhIP). The average HCA content of the control patties was 7 ng/g MeIQx and 6.53 ng/g PhIP. Turmeric (39.2% inhibition), fingerroot (33.5% inhibition), and galangal (18.4% inhibition) significantly decreased HCAs compared with the control. But, only turmeric and fingerroot were as effective as rosemary in preventing HCA formation. The HCA inhibition in patties containing spices was significantly correlated to the total phenolic content (R(2) = 0.80) and the scavenging activity (R(2) = 0.84) of the spices as measured by the 2,2-diphenyl-β-picrylhydrazyl assay. Results of this study suggest that addition of Asian spices can be an important factor in decreasing the levels of HCAs in fried beef patties.     

Concentration-dependent inhibition of Escherichia coli O157:H7 and heterocyclic amines in heated ground beef patties by apple and olive extracts,onion powder and clove bud oil

The effects of plant compounds on Escherichia coli O157:H7 and two major heat-induced heterocyclic amines (HCAs) MeIQx and PhIP in grilled ground beef patties were determined. Ground beef with added apple and olive extracts, onion powder, and clove bud oil was inoculated with E. coli O157:H7 (10⁷ CFU/g) and cooked to reach 45 °C at the geometric center, flipped and then cooked for another 5 min. Cooled samples were taken for microbiological and HCA analyses. Olive extract at 3% reduced E. coli O157:H7 to below detection. Reductions of up to 1 log were achieved with apple extract. Olive and apple extracts reduced MeIQx by up to 49.1 and 50.9% and PhIP by up to 50.6 and 65.2%, respectively. Onion powder reduced MeIQx and PhIP by 47 and 80.7%, respectively. Inactivation of E. coli O157:H7 and suppression of HCAs in grilled meat were achieved by optimized amounts of selected plant compounds.     

Effect of Marinades on the Formation of Heterocyclic Amines in Grilled Beef Steaks

ABSTRACT:  Heterocyclic amines (HCAs) are suspected human carcinogens formed in muscle foods during high temperature grilling or cooking. Inhibition of HCAs by commercial marinades rich in polyphenolic antioxidant containing spices was evaluated with beef round steaks cooked at 204 °C (400 °F). Treatment effects on the levels of 4 HCAs were investigated: 2-amino-3,8-dimethylimidazo[4,5- f ]quinoxaline (MeIQx), 2-amino-1-methyl-6-phenyl-imidazo[4,5- b ]pyridine (PhIP), 1-methyl-9H-pyrido[4,3- b ]indol (harman), and 9H-pyrido[4,3- b ]indol (norharman). The marinades were formulated according to the package label instruction in an oil, water, and vinegar mixture, and the steaks were treated for 1 h prior to grilling. All 3 marinades, Caribbean, Southwest, and herb, significantly decreased the imidazo-azaarene HCAs (MeIQx, PhIP) as contrasted to controls and liquid blanks. The Caribbean mixture showed the highest decrease in the total HCA content (88%), followed by the herb (72%) and Southwest (57%). With a few exceptions there were significant decreases in HCAs for treatments with only the marinade bases (ingredients without any spices/herbs). As measured by high-performance liquid chromatography (HPLC), the marinades contained considerable amounts of the polyphenolic antioxidants carnosic acid, carnosol, and rosmarinic acid with Caribbean being the highest. Commonly available spice-containing marinades can be effective inhibitors of HCA formation and provide reduced exposure to some of the carcinogens formed during grilling.     

Influence of fructooligosaccharides and garlic on formation of heterocyclic amines in fried ground beef patties

The effects of fructooligosaccharide (FOS) and garlic on the formation of 15 heterocyclic amines (HCAs) were evaluated in fried beef patties. The HCAs were extracted from the fried meat samples and purified using a solid-phase extraction method and then analyzed on a liquid chromatography-mass spectrometry. Among the 15 HCAs, 3-amino-1, 4-dimethyl-5H-pyrido-[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido [4,3-b]indole (Trp-P-2), 2-amino-6-methyldipyrido [1,2-a:3′,2′-d]imidazole (Glu-P-1), 2-aminodipyrido [1,2-a:3′,2′-d]imidazole (Glu-P-2), 9H-pyrido [3,4-b]indole (norharman), 1-methyl-9H-pyrido [3,4-b]indole (harman), 2-amino-9H-pyrido [2,3-b]indole (AαC), 2-amino-3,8 dimethylimidazo [4,5-f]-quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo [4,5-b]-pyridine (PhIP) were detected in all of the cooked beef patties. Analysis of variance revealed that the addition of 1 or 3 g of FOS significantly reduced the formation of total amino-carboline type HCAs in the cooked beef patties, and adding the 1 or 3 g of FOS to ground beef patties reduced levels of PhIP and MeIQx (amino-imidazo-azaarenes; AIAs) in the patties. When it is compared with the HCA formation in control, additions of minced garlic (5.0, 10.0, and 15.0 g) to the ground beef patties (100 g) reduced HCA formation in the range of 14 to 100%.     

Formation of heterocyclic aromatic amines in doner kebab cooked with different methods at varying degrees of doneness

This study was designed to determine the formation of heterocyclic aromatic amines (HCAs) in two different types of doner kebab (yaprak doner-YD or mix doner-MD) cooked with different cooking methods (gas or electric) at varying degrees of doneness (rare, medium, well-done). In doner samples, nine common HCAs (IQ, IQx, MeIQ, MeIQx, PhIP, 4,8-DiMeIQx, 7,8-DiMeIQx, AαC, MeAαC) were detected. Additionally, the changes in the HCA precursors were evaluated. The initial concentration of precursors gradually decreased with the increase in doneness degree due to degradation or possible contribution in the Maillard reaction to form HCA compounds as a result of heat treatment (p < 0.05). Creatine content decreased, while creatinine content increased because of the conversion reaction. The two most abundant HCA in doner samples were 4,8-DiMeIQx and IQ, which measured in the range of 0.020–2.865 ng g^?1 and 0.052–0.513 ng g^?1, respectively. Other detected HCAs were determined in especially well-done samples. In conclusion, the diversity and the amount of each HCA compound in doner kebab samples showed variation depending on the effect of doneness degree, doner kebab type or cooking methods (p < 0.05).     

迷迭香提取物对冷藏调理猪肉饼品质的影响

研究不同剂量迷迭香提取物对4 ℃冷藏调理猪肉饼抗脂肪氧化、抑菌能力及品质特性的影响。将0.03%、0.06%和0.09%的迷迭香提取物分别添加到调理猪肉饼中,测定其在10 d冷藏过程中硫代巴比妥酸值、菌落总数、pH值、颜色（L*、a*、b*值）、出品率和感官指标的变化。结果表明：与对照组相比,添加迷迭香提取物的各处理组具有显著的抗脂肪氧化效果和更高的出品率（P＜0.05）,效果与添加0.02%二丁基羟基甲苯相当。迷迭香提取物添加量为0.06%和0.09%的处理组在冷藏7 d后表现出显著的抑菌能力（P＜0.05）,这两组的pH值在冷藏期间显著低于对照组（P＜0.05）。迷迭香提取物添加量为0.06%的猪肉饼在冷藏4 d后红度值（a*）与对照组相比显著升高（P＜0.05）,迷迭香提取物添加量为0.09%的猪肉饼在10 d冷藏过程中亮度值（L*）显著低于对照组（P＜0.05）,而这两组猪肉饼的黄度值（b*）在冷藏期间均显著高于对照组（P＜0.05）。此外,猪肉饼的香气、质地和总体可接受程度均没有随迷迭香提取物添加量的增加而发生显著变化（P＞0.05）。可见,迷迭香提取物在调理猪肉饼中具有较好的抗氧化和抑菌效果,并且在一定程度上能改善肉饼颜色,而对肉饼的感官品质不会造成不良影响。     

Effect of enhancement on the formation of heterocyclic amines in cooked pork loins: Preliminary studies

Heterocyclic amines (HCAs) which are produced in meats cooked at high temperature a risk factor for certain human cancers. This study evaluated the effect of enhancement on HCA formation in cooked pork loins. Three samples of pork loin were prepared including non-injected loin, 12% water-injected loin, and 12% salt/phosphate injected loin. The HCAs were identified in all samples: PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine), MeIQx (2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline), and DiMeIQx (2-amino-3,4,8-trimethylimidazo [4,5-f]quinoxaline). Injection of salt/phosphate significantly reduced the level of PhIP by 42.7%, MeIQx by 79.0%, and DiMeIQx by 75.0%. Enhancement with water alone did not reduce HCA formation.     

Influence of food condiments on the formation of carcinogenic heterocyclic amines in cooked chicken and determination by LC-MS/MS

Heterocyclic amines (HCAs) are known to be suspected human carcinogens produced by high-temperature cooking of protein-rich foods such as meat and fish. In the present study, the influence of numerous food condiments on the formation of HCAs in cooked chicken was investigated. Chicken samples were subjected to pan-frying under controlled temperature. The levels of HCAs DMIP, MeIQx, 4,8-DiMeIQx, PhIP, harman and norharman were found to be between 0.93 and 27.52 ng g^?1, whereas IQ, MeIQ, AαC, MeAαC, Trp-P-1 and Trp-P-2 were found either below the limit of quantification or not detected in the control sample. Nevertheless, for samples cooked using food condiments, the amounts of HCAs (DMIP, MeIQx, 4,8-DiMeIQx and PhIP) were between 0.14 and 19.57 ng g^?1; harman and norharman were detected at higher concentrations up to 17.77 ng g^?1 while IQ and MeIQ were at levels below the limit of quantification; and AαC, MeAαC, Trp-P-1 and Trp-P-2 were not detected in any of the samples. The outcomes revealed that the formation of HCAs (except harman and norharman) diminished after the addition of food condiments. Edible oil contributed to the highest levels of HCA formation, followed by garlic, paprika, pepper and tomato.     

Influence of extra virgin olive oil on the formation of heterocyclic amines in roasted beef steak

In this study, heterocyclic anime (HCA) contents were monitored in commonly consumed pan-fried beefsteak based on the highest level of human exposure. Effect of addition of extra virgin olive oil (EVOO) on HCAs formation in fried beef steaks was evaluated. After EVOO was spread on the meat surface, the raw beef was cooked at 200°C for 5 min on each side. The HCAs were extracted from the meat samples and purified using a solid-phase extraction method and then analyzed by liquid chromatography-mass spectrometry (LC-MS). Among the 15 HCAs, 3-amino-1,4-dimethyl-5H-pyrido-[4,3-b]indole (Trp-P-1), 3-amino-1-methyl-5H-pyrido [4,3-b]indole (Trp-P-2), 9H-pyrido [3,4-b]indole (Norharman), 1-methyl-9H-pyrido [3, 4-b]indole (Harman), 2-amino-9H-pyrido [2,3-b]indole (AαC), 2-amino-3-methyl-9H-pyrido [2,3-b]indole (MeAαC), 2-amino-3,8-dimethylimidazo [4,5-f]-quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo [4,5-b]-pyridine (PhIP) were detected in all of the cooked beefsteaks. HCAs formation was significantly reduced (p<0.05) when the EVOO was added to the beef prior to cooking. The addition of 2 and 4 g of EVOO considerably inhibited HCAs formation in the fried beefsteak. However, adding excess amounts of EVOO promoted some HCAs formation.     

Influence of natural food ingredients on the formation of heterocyclic amines in fried beef patties and chicken breasts

The effects of natural food ingredients including Korean bramble, onion, and marinade sauce with water extracts of olive and lotus leaf on the formation of 15 heterocyclic amines (HCAs) were evaluated in fried beef patties and chicken breasts. The patties and chicken breasts containing natural food ingredients were fried at 230 and 200°C for 8 min on each side. Addition of 4 g Korean bramble to beef patties reduced the formation of 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 9H-pyrido [3,4-b]indole (Norharman), and 2-amino-6-methyldipyrido [1,2-a:3′,2′-d]imidazole (Glu-P-1) by 74, 62, and 39%, respectively. Also, when 2 g onion was added to beef patties, the formation of 2-amino-3,4,8-trimethylimidazo [4,5-f]quinoxaline (4,8-DiMeIQx), Glu-P-1, MeIQ, Norharman, and 2-amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine (PhIP) was inhibited by 100, 96, 88, 74, and 79%, respectively. When marinade sauce containing 2% water extracts of olive and lotus leaf was added to chicken breasts, most HCAs formation was inhibited. Especially, the formation of Glu-P-1, 2-aminodipyrido [1,2-a:3′,2′-d]imidazole (Glu-P-2), and MeIQ were reduced by 100%.     

Antioxidant capacity and inhibitory effect of grape seed and rosemary extract in marinades on the formation of heterocyclic amines in fried beef patties

The effect of oil-based marinades containing grape seed extract (Vitis vinifera L.; 0.2, 0.4, 0.6 and 0.8 g/100 g) formulated in a water/oil emulsion or rosemary extract (Rosmarinus officinalis; 0.12, 0.2, 0.6, 1.0 and 1.5 g/100 g) in oil on the formation of heterocyclic amines (HAs) in fried beef patties was examined. After application of marinades and frying, four HAs MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline), PhIP (2-amino-1-methyl-6-phenylimidazo[4,5b]pyridine), Norharman, and Harman were found at low levels in all fried patties, MeIQx (0.3–1.0 ng/g), and PhIP (0.02–0.3 ng/g). The content of MeIQx and PhIP were significantly reduced by approx. 57% and 90% (p < 0.05), respectively, after use of marinades containing the highest extract concentration. The antioxidant capacity of grape seed was about two-times greater than that of rosemary extract. A correlation between inhibition of HAs and Trolox-equivalents (MeIQx, R² = 0.85, p < 0.001; PhIP, R² = 0.83, p < 0.001) was found. Sensory tests showed a high acceptance of flavour and colour for controls and samples.     

Occurrence of heterocyclic amines in cooked meat products

Heterocyclic amines (HCAs), potent mutagens and a risk factor for human cancers, are produced in meats cooked at high temperature. The aim of this study was to determine the HCA content in cooked meat products (beef, chicken, pork, fish) prepared by various cooking methods (pan frying, oven broiling, and oven baking at 170 to 230 °C) that are preferred by U.S. meat consumers. The primary HCAs in these samples were PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine) (1.49-10.89 ng/g), MeIQx (2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline) (not detected-4.0 ng/g), and DiMeIQx (2-amino-3,4,8-trimethyl-imidazo [4,5-f]quinoxaline) (not detected-3.57 ng/g). Type and content of HCAs in cooked meat samples were highly dependent on cooking conditions. The total HCA content in well-done meat was 3.5 times higher than that of medium-rare meat. Fried pork (13.91 ng/g) had higher levels of total HCAs than fried beef (8.92 ng/g) and fried chicken (7.00 ng/g). Among the samples, fried bacon contained the highest total HCA content (17.59 ng/g).     

Amino acids effects on heterocyclic amines formation and physicochemical properties in pan-fried beef patties

The effects of surface application of amino acids on the formation of heterocyclic amines (HCAs) and meat quality properties were evaluated in pan-fried beef patties (230 °C/15 min). Tryptophan, lysine, leucine, and proline at three concentrations, 0.05%, 0.20%, and 0.50% (w/w), were tested. The meat crusts were analyzed for HCA content using liquid chromatography-tandem mass spectrometry. Results showed that surface application of all tested amino acids significantly reduced total HCA content (P < 0.05), and the interaction of amino acid type and concentration significantly affected (P < 0.05) both individual and total HCA formation. Tryptophan at 0.50% reduced total HCAs the most (0.92 ng/g, 93% inhibition), followed by 0.50% lysine (1.94 ng/g, 84% inhibition), while leucine (3.95 ng/g, 64% inhibition) and proline (4.71 ng/g, 56% inhibition) were less effective at 0.50%. In addition, applying amino acids to meat surface significantly influenced (P < 0.05) pH and surface color change of beef crusts; particularly, lysine at 0.20% and 0.50% increased pH and a^* (redness) but reduced b^* (yellowness), while tryptophan and leucine at 0.50% increased L^* (whiteness). No significant effect was observed on cooking loss. Adding amino acids at 0.50% affected (P < 0.05) formation of aldehydes and pyrazines (as the key flavor compounds of fried beef). Overall, the results of this study suggested that adding amino acids to ground beef patties could effectively mitigate mutagenic HCA formation during cooking.     

Heterocyclic amine content in commercial ready to eat meat products

Heterocyclic amines (HCAs) are produced in meats cooked at high temperature, which are potent mutagens and a risk factor for human cancers. The aim of this study was to estimate the amount of HCAs in some commonly consumed ready-to-eat (RTE) meat products. The RTE products were purchased from a local grocery store, and HCA were analyzed using an analytical method based on solid-phase extraction followed by HPLC. The primary HCAs in these samples were PhIP (2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine) (not detected-7.9 ng/g) and MeIQx (2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline) (not detected-3.6 ng/g). Products ranked in order of increasing total HCA content: pepperoni (0.05 ng/g)相似文献   

Formation of heterocyclic amine–amino acid adducts by heating in a model system

Although mutagenic and carcinogenic heterocyclic amines (HCAs) are known to be formed in cooked meat and fish, human HCA exposure and carcinogenic risk have not been elucidated in sufficient detail. In this work, we investigated the formations of HCA–amino acid adducts in a model system by using a liquid chromatography–mass spectrometry to elucidate another source of human HCA exposure. The 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) adduct with glycine was formed easily by heating at 200 °C within 5 min, which is probably based on the dehydration condensation of the amino group of PhIP and carboxyl group of glycine. PhIP and other HCAs such as 2-amino-3-methyl-3H-imidazo[4,5-f]quinolone, 2-amino-3,8-dimethylimidazo[4,5-f]-quinoxaline and 3-amino-1,4-dimethyl-5H-pyrido[3,4-b]indole, also bound with various amino acids by heating. Among these amino acids, proline tends to form adducts with HCAs, but serine, cysteine and lysine hardly bound with HCAs. These results provided a basic understanding of the formation of HCA adducts with amino acids during cooking.     

迷迭香提取物对真空包装熟猪肉饼抗氧化和抑菌效果的影响

以真空包装熟猪肉饼为试材,探讨不同质量分数迷迭香提取物的抗氧化、抑菌能力及其对肉饼品质的影响。将0.03%、0.06%和0.09%的迷迭香提取物分别添加到肉饼中,对肉饼在10 d冷藏期间的硫代巴比妥酸（thiobarbituricacid reactive substance,TBARS）值、菌落总数、挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量、pH值、红度值（a*）和质构进行测定,并与0.02%二丁基羟基甲苯（butylated hydroxytoluene,BHT）进行比较。结果表明：添加迷迭香提取物的各处理组抗脂肪氧化能力高于空白对照组（P＜0.05）,迷迭香提取物添加量为0.09%的处理组在前7 d的冷藏过程中抑菌能力显著高于空白对照组（P＜0.05）。添加迷迭香提取物的各处理组TVB-N含量在冷藏4 d后显著低于空白对照组,而pH值在整个冷藏过程中均显著低于空白对照组（P＜0.05）。在冷藏1 d后,添加0.09%迷迭香提取物的肉饼a*值与空白对照组相比显著上升,而在冷藏7、10 d后,添加迷迭香提取物的各处理组a*值均显著升高（P＜0.05）。此外,添加迷迭香提取物的各处理组咀嚼性在冷藏4、7、10 d后显著升高,硬度在冷藏1、10 d后显著升高,迷迭香提取物添加量为0.09%的肉饼在冷藏4、7 d后硬度也显著提升（P＜0.05）。可见,迷迭香提取物能有效抑制真空包装熟猪肉饼的脂肪氧化及微生物生长,并且能在一定程度上改善其颜色和质构。     

Heterocyclic Amines: 2. Inhibitory Effects of Natural Extracts on the Formation of Polar and Nonpolar Heterocyclic Amines in Cooked Beef

ABSTRACT: The effects of natural extracts on the formation of polar (IQ, MeIQ, MeIQx, 4,8-DiMeIQx, and PhIP) and nonpolar (norharman, harman, and AαC) heterocyclic amines (HAs) were examined in ground beef cooked at 200 and 210°C for 20 min. In experiment 1, the formation of MeIQx was effectively reduced by 77%, 75%, and 69%, respectively, for 1.0% pine bark extract (Pycnogenol®), 1.0% Oleoresin rosemary (Herbalox®), and grape seed extract (ActiVin^TM) at 200°C for 20 min. No 4,8-DiMeIQx was observed in the 1.0% ActiVin. When compared with the initial concentrations, glucose and creatine significantly decreased for all treatments and the control at 200°C after 20 min. In experiment 2, IQ was not formed in any treatment when beef was fried at 210°C for 10 min/side. The formation of MeIQx was reduced by 64% and 61% at 1.0% ActiVin and 1.0% Pycnogenol. Herbalox (1.0%) more effectively decreased the amount of nonpolar HAs than other treatments. No AαC and norharman were detected at 1.0 % Herbalox. Natural extracts, ActiVin, Pycnogenol, and Herbalox, effectively decreased the formation of polar and nonpolar HAs. The results provide valuable information to inhibit the formation of HAs in cooked meats.     

葡萄籽提取物对烤羊肉中杂环胺形成的影响

将0.05%VE,0.1%与0.5%葡萄籽提取物,0.1%与0.5%槲皮素分别添加于羊肉表面,在200℃下煎烤10 min,利用固相萃取-配备二极管阵列检测器和荧光检测器的高效液相色谱分析烤羊肉中15种杂环胺的形成量,以探讨天然提取物对烤羊肉中杂环胺形成量的影响。结果表明:烤羊肉中共检测出10种杂环胺,其中极性杂环胺4种,非极性杂环胺6种,总量达51.68 ng/g。在极性杂环胺中2-氨基-1-甲基-6-苯基-咪唑并[4,5-b]吡啶(PhIP)的形成量较高,达10.50 ng/g;非极性杂环胺中9H-吡啶并[3,4-b]吲哚(Norharman)与1-甲基-9H-吡啶并[3,4-b]吲哚(Harman)的形成量较高,分别达19.66 ng/g与12.23 ng/g。烤羊肉中添加天然抗氧化剂只对极性杂环胺有抑制作用,其中添加0.5%葡萄籽提取物可以显著抑制2-氨基-3甲基咪唑并[4,5-f]喹啉(IQ),2-氨基-3,8-二甲基咪唑并[4,5-f]喹喔啉(MeIQx),2-氨基-3,4,8-三甲基咪唑并[4,5-f]喹喔啉(4,8-DiMeIQx)与PhIP 4种极性杂环胺的形成(P<0.05),其生成量分别减少36.65%,67.73%,35.63%与30%。天然抗氧化剂对烤羊肉中非极性杂环胺的抑制作用不明显。     

Formation of protein adducts of 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine in cooked foods

Heterocyclic amines (HCAs) are mutagenic and carcinogenic compounds found in cooked meat and fish. Although HCAs are known to form adducts with protein after metabolic activation, adduct formation during cooking has not been elucidated. In this study, we showed that 2‐amino‐1‐methyl‐6‐phenylimidazo[4,5‐b]pyridine (PhIP) is released from high molecular weight compounds by acid or enzymatic hydrolysis of cooked foods. Formation of free and protein adduct forms of PhIP was dependent on cooking temperature and time, and PhIP–protein adducts were estimated to form after formation of free PhIP. We also demonstrated that PhIP–protein adduct is formed by heating of PhIP and albumin as a model protein. A new adduct peak including [M+H]⁺ (m/z=225) of PhIP as a fragment ion was detected in the high molecular weight fraction of heat‐treated protein by LC–MS analysis. From model experiments by heating of PhIP and amino acids, the adduct was estimated to be produced by condensation of the amino group of PhIP and the carboxyl group of protein. PhIP–protein adducts were detected in several cooked meat and fish at ng/g food level as PhIP content. These results suggest that food‐borne protein adducts of HCAs may influence human HCA exposure and carcinogenic risk.