Modelling the formation of heterocyclic amines in slices of longissimus thoracis and semimembranosus beef muscles subjected to jets of hot air

The formation of heterocyclic amines (HAs) was modelled in slices of longissimus thoracis (LT) and semimembranosus (SM) beef muscles subjected to jets of hot air at temperatures ranging from 170 and 250 °C and treatment times ranging from 1 to 20 min. The quantity of HAs formed in the SM muscle was clearly less that that formed in the LT muscle as soon as the heat treatment was longer than 300 s. The extreme dehydration obtained with the hot-air jets slowed the formation of IQx, MeIQx and, particularly, 4,8-DiMeIQx compared with superheated steam treatments. The reverse effect was observed for PhIP concentrations which increased 1.4- to 5.5-fold. This highlights the important effect of water activity variations on HA formation, even at very low a_w values.     

Inhibitory effect of marinades with hibiscus extract on formation of heterocyclic aromatic amines and sensory quality of fried beef patties

Heterocyclic aromatic amines (HAA) are carcinogenic compounds found in the crust of fried meat. The objective was to examine the possibility of inhibiting HAA formation in fried beef patties by using marinades with different concentrations of hibiscus extract (Hibiscus sabdariffa) (0.2, 0.4, 0.6, 0.8 g/100 g). After frying, patties were analyzed for 15 different HAA by HPLC-analysis. Four HAA MeIQx (0.3–0.6 ng/g), PhIP (0.02–0.06 ng/g), co-mutagenic norharmane (0.4–0.7 ng/g), and harmane (0.8–1.1 ng/g) were found at low levels. The concentration of MeIQx was reduced by about 50% and 40% by applying marinades containing the highest amount of extract compared to sunflower oil and control marinade, respectively. The antioxidant capacity (TEAC-Assay/Folin–Ciocalteu-Assay) was determined as 0.9, 1.7, 2.6 and 3.5 μmol Trolox antioxidant equivalents and total phenolic compounds were 49, 97, 146 and 195 μg/g marinade. In sensory ranking tests, marinated and fried patties were not significantly different (p > 0.05) to control samples.     

Effect of lipid oxidation products on the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in model systems

Ternary mixtures of creatinine, phenylalanine and lipids (or carbohydrates) were heated at 200 °C for 1 h to determine the potential contribution of lipids to the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Although unoxidised lipids did not contribute to PhIP formation, their oxidation produced many compounds that significantly increased the formation of PhIP. Among the different lipid oxidation products (LOPs) studied, which included ω-6 and ω-3 derived lipid hydroperoxides, 2,4-alkadienals, 2-alkenals, 4,5-epoxy-2-alkenals, 4-oxo-2-alkenals, and 4-hydroxy-2-nonenal, 4-oxo-2-nonenal was the most reactive compound. It produced 32.48 pmol of PhIP/μmol of creatinine in comparison with the 7.92 pmol of PhIP/μmol of creatinine produced by the control phenylalanine/creatinine reaction mixture. 4-Oxo-2-nonenal reactivity was similar to that of most carbohydrates; although ribose and arabinose produced more PhIP (44–46 pmol of PhIP/μmol of creatinine). In addition to single LOP, the addition of oxidised soybean oil for 24–144 h at 60 °C also increased PhIP formation. All these results pointed out to a potential contribution of LOP to the formation of PhIP in food products. This contribution will depend on the lipid content of the food product and its easiness to be oxidised.     

Inhibition of heterocyclic amine formation by water-soluble vitamins in Maillard reaction model systems and beef patties

The inhibitory activities of 11 water-soluble vitamins against heterocyclic amine formation were examined in a PhIP and a MeIQx producing chemical model. Six investigated vitamins (pyridoxiamine, pyridoxine, nicotinic acid, biotin, thiamine and l-ascorbic acid) out of the 11, exhibited significant inhibition (>40%) in both models. Pyridoxamine was the most potent inhibitor, and its inhibitory effect increased with increasing concentration in the model, although not in a linear manner. The activity of pyridoxamine, niacin and ascorbic acid was investigated using fried beef. Moderate inhibition (∼20%) of the formation of PhIP, 4,8-DiMeIQx and MeIQx was found for niacin and ascorbic acid; whereas pyridoxamine reduced the levels of all three HAs by ∼40%. GC–MS analysis showed that pyridoxamine significantly reduced the level of PhIP intermediate, phenylacetaldehyde. LC–ESI–MS/MS analysis revealed that pyridoxamine directly reacts with phenylacetaldehyde to form an adduct, whose structure was characterised by MS and NMR spectroscopy.     

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.     

Effects of varying degrees of doneness on the formation of Heterocyclic Aromatic Amines in chicken and beef satay

The study was carried out to determine the effect of cooking method on Heterocyclic Aromatic Amines (HAs) concentration in grilled chicken and beef (satay). Six common HAs were investigated: 2-amino-3-methylimidazo[4,5-f]quinolone (IQ), 2amino 3,4dimethylimidazo [4,5f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8 trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-3,7,8trimethylimidazo [4,5-f]quinoxaline (7,8-DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP). Chicken and beef satay samples were grilled to medium and well done level of doneness. Charcoal grilled (treatment A), microwave pre-treatment prior to grilling (treatment B), and microwave-deep fried (treatment C) were applied to beef and chicken satay samples. The satay samples which were microwaved prior to grilling (B) showed significantly (p < 0.05) lower HAs concentration as compared to those charcoal grilled (A). Both medium and well done cooked beef and chicken satay samples that were microwaved and deep fried (C) as an alternative method to grilling were proven to produce significantly lesser HAs as compared to charcoal-grilled (A) and microwaved prior to grilling (B).     

Comparative formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in creatinine/phenylalanine and creatinine/phenylalanine/4-oxo-2-nonenal reaction mixtures

The comparative formation of the heterocyclic aromatic amine 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in both creatinine/phenylalanine (CRN/Phe) and creatinine/phenylalanine/4-oxo-2-nonenal (CRN/Phe/ON) systems was studied to analyse the ability of lipid-derived reactive carbonyls to promote PhIP formation. Although PhIP was produced to some extent in the CRN/Phe system, the presence of the oxidized lipid increased considerably the amount of PhIP produced. This increase seemed to be a consequence of the decrease in the E_a of the reaction when the lipid was present, which diminished from 112.9 to 80.9 kJ/mol. On the other hand, the addition of the lipid did not seem to produce PhIP by an alternative mechanism because PhIP was formed analogously in both CRN/Phe and CRN/Phe/ON systems as a function of pH, creatinine concentration, phenylalanine concentration, time, temperature, oxygen concentration in the reaction atmosphere, and the addition of different amounts of ammonia. All these results suggest that the ability of lipid oxidation products to produce PhIP is related to their capacity to induce the Strecker degradation of phenylalanine to phenylacetaldehyde. Therefore, any other reactive carbonyl compound that can produce the Strecker degradation of phenylalanine should also be considered as a potential inducer of PhIP formation under appropriate conditions.     

Effect of amino acids on the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in creatinine/phenylalanine and creatinine/phenylalanine/4-oxo-2-nonenal reaction mixtures

2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation in mixtures of creatinine, phenylalanine, amino acids and 4-oxo-2-nonenal was studied, to analyse the role of amino acids on the generation of this heterocyclic aromatic amine. When oxidised lipid was absent, cysteine, serine, aspartic acid, threonine, asparagine, tryptophan, tyrosine, proline, and methionine increased significantly (p < 0.05) the amount of PhIP formed in comparison to the control. When lipid was present, only the addition of methionine, glycine, and serine increased significantly (p < 0.05) the amount of PhIP produced, while histidine, cysteine, lysine, tryptophan, tyrosine, and alanine reduced significantly (p < 0.05) PhIP. These results may be a consequence of the different competitive reactions that occur. Thus, in the absence of lipids, thermal decomposition of the amino acids produced reactive carbonyls that converted phenylalanine into phenylacetaldehyde as a key step in the formation of PhIP. When oxidised lipid was present, amino acids competed with phenylalanine for the lipid, and amino acid degradation products were formed, among which alpha-keto acids seemed to play a role in these reactions. These results suggest that PhIP can be produced by several alternative reaction pathways from all major food components, including amino acids and lipids, in addition to carbohydrates.     

Effect of green tea marinades on the formation of heterocyclic aromatic amines and sensory quality of pan-fried beef

The effect of a green tea marinade on the formation of heterocyclic aromatic amines (HAs) was examined in pan-fried beef cooked at 180–200 °C for 4 min each side. Different marinating times were assayed and unmarinated samples cooked in similar conditions provided reference HAs levels. A green tea marinade catechin rich was prepared taking 1 g of green tea and infusing with 125 ml of boiling tap water during 10 min. Four HAs were quantified in unmarinated and marinated meat samples during 1, 2, 4 and 6 h at 5 °C. Compared with the unmarinated samples, marinating in green tea resulted in a significant decrease (p < 0.05) of levels of PhIP and AαC. Person correlation indicated that the reduction of the levels of these HAs in meat marinated with the increase of marinating time was significant (respectively, r = −0.799, p < 0.0001; r = −0.631, p < 0.05). No reduction was observed for 4,8-DiMeIQx and MeIQx.     

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%.     

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。     

Inhibition of Heterocyclic Amine Formation in Beef Patties by Ethanolic Extracts of Rosemary

ABSTRACT: Heterocyclic amines (HCAs) are mutagenic compounds formed during cooking muscle foods at high temperature. Inhibition of HCAs by rosemary extracts were evaluated with beef patties cooked at 191 °C (375 °F) for 6 min each side and 204 °C (400 °F) for 5 min each side. Five rosemary extracts extracted with different solvents were used in this study: extract 100W (100% water), 10E (10% ethanol), 20E (20% ethanol), 30E (30% ethanol), and 40E (40% ethanol). The 5 extracts were directly added to beef patties at 3 levels (0.05%, 0.2%, and 0.5%) before cooking and HCA contents were extracted and quantified. All of the patties contained 2-amino-3,8-dimethylimidazo [4,5-f]quinoxaline (MeIQx), and 2-amino-1-methyl-6-phenylimidazo [4,5-b]pyridine (PhIP). There was no statistical difference in the inhibition of HCAs in the 0.05%, 0.2%, and 0.5% rosemary extracts. All rosemary extracts significantly decreased the levels of MeIQx and PhIP at both cooking conditions. When cooking at 204 °C (400 °F) for 5 min each side, rosemary extracts 10E and 20E were superior to rosemary extracts 100W, 30E, and 40E in inhibiting HCA formation. Rosemary extract 20E showed the greatest inhibition of MeIQx (up to 91.7%) and PhIP (up to 85.3%). The inhibiting effect of rosemary extracts on HCA formation corresponded to their antioxidant activity based on a DPPH scavenging assay. Rosemary extract 10E and 20E contain a mixture of rosmarinic acid, carnosol, and carnosic acid. It is possible that these compounds might act synergistically in inhibiting the formation of HCAs.     

Effects of cooking methods on the formation of heterocyclic aromatic amines of two different species trout

Heterocyclic aromatic amines (HAAs) are sometimes formed in meats and fish cooked at high temperatures. In the present study, the effects of cooking methods by deep-fat frying, pan-frying, grilling and barbecuing on the formation of HAAs of fillets of rainbow trout (Oncorhynchus mykiss) and brown trout (Salmo trutta fario) were investigated. Barbecued brown trout (1 g) was estimated to contain 0.12 ng of IQ (2-amino-3-methylimidazo[4,5-f]quinoline), 0.02 ng 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline). Grilled rainbow trout (1 g) was estimated to contain 0.02 ng 4,8-DiMeIQx. MeIQ (2-amino-3,4-dimethylimidazo[4,5-f]quinoline), MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline) and PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine) were not detectable in all cooked fish.     

Effects of ageing and low internal temperature of grilling on the formation of heterocyclic amines in beef Longissimus dorsi muscle

The mutagenic heterocyclic amines (HAs) originate in processed proteinaceous food. The effects of ageing (non-aged - i.e. 24 h post mortem vs. 14 and 28 days post mortem kept at 1 °C) and final internal temperature on cooking (T_i, 65 and 80 °C) on the content of HAs in grilled steaks (two-plated grill, temperature of 220 °C) were studied. HA precursors (creatine, creatinine, and free amino acids) and ageing indicators, such as instrumentally measured colour values, pH_ultimate values and length of myofibrilar fragments on raw and cutting values on grilled beef Longissimus dorsi muscles were determined. The muscles originated from eight commercially slaughtered Simmental bulls, 19-20 months old. The content of HAs was determined by a solid-phase extraction procedure. Meat ageing is accompanied by large changes in the chemical composition and structure of muscle tissues. In general, all the ageing indicators and precursors of HAs were influenced by ageing time at the 5% level or less. Creatine content declined significantly (non-aged: 6.00 mg g⁻¹, 14 days: 5.82 mg g⁻¹, and 28 days: 5.55 mg g⁻¹) and creatinine increased with days of ageing (non-aged: 0.19 mg g⁻¹, 14 days: 0.24 mg g⁻¹, and 28 days: 0.26 mg g⁻¹). Higher contents of total free amino acids were determined after 14 and 28 days of storage (28.18 μmol g⁻¹ and 37.59 μmol g⁻¹) than in non-aged beef (19.00 μmol g⁻¹). In this study, two HAs were determined: MeIQx (2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline) and PhIP (2—amino-1-methyl-6-phenylimidazo-[4,5-b]pyridine). The content of HAs increases with ageing. At lower T_i, more MeIQx was formed; at higher T_i, more PhIP was formed. MeIQx was present in all samples while PhIP was found only in samples grilled to higher T_i. Samples treated to T_i = 80 °C generally contained less HAs (non-aged meat: 0.20 ng g⁻¹, 14 days: 0.26 ng g⁻¹, and 28 days: 0.28 ng g⁻¹) than samples treated to T_i = 65 °C (non-aged meat: 0.19 ng g⁻¹, 14 days: 0.36 ng g⁻¹, and 28 days: 0.39 ng g⁻¹) on account of MeIQx thermolability.     

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).     

Antioxidant spices reduce the formation of heterocyclic amines in fried meat

 Heterocyclic aromatic amines (HAs) are mutagenic compounds that are formed during heating of meat and fish. These substances are reaction products of creatine with amino acids and carbohydrates. It is recommended that exposure to these probable human carcinogens should be minimised. Five heterocyclic aromatic amines which occur in beef were investigated: 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethyl-imidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethyl-imidazo[4,5-f]quinoxaline (4,8-DiMeIQx), and 2-amino-1-methyl-6-phenyl-imidazo[4,5-b]pyridine (PhIP). Clean-up was done by acid-base partition followed by SPE using blue cotton. HPLC analysis was carried out by using electrochemical detection for IQ- and IQx-type compounds and fluorescence detection for PhIP. The concentrations of the aromatic amines were as follows: IQ, 10.2 μg/kg; MeIQ, 2.46 μg/kg; MeIQx, 13.2 μg/kg; 4,8-DiMeIQx, 2.26 μg/kg; and PhIP, 5.48 μg/kg. The application of spices (rosemary, thyme sage, garlic, brine) reduced the content of the HAs below 60% of the amount found in the control. Received: 23 April 1998     

Formation and mitigation of heterocyclic aromatic amines in fried pork

Heterocyclic aromatic amines (HAAs) are potent mutagens and carcinogens generated during the heat processing of meat. HAAs, which are abundant in processed meat products, include 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), and 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP). The content of these three HAAs in fried pork was determined by LC-MS/MS. The effects of frying time and temperature, sample shape, and addition of antioxidants on the generation of HAAs were investigated. The results show that HAAs were produced during frying, and their levels increased with increasing frying time and temperature. Pork patties had the highest concentration of HAAs compared with pork meatballs and pork strips. The addition of antioxidant of bamboo leaves (AOB), liquorice extract, tea polyphenol, phytic acid and sodium iso-ascorbate to pork before frying had an inhibitory effect on HAA generation, with AOB being the most effective antioxidant. Inhibition levels of nearly 69.73% for MeIQx, 53.59% for 4,8-DiMeIQx and 77.07% for PhIP in fried pork were achieved when the concentrations of AOB added were 0.02, 0.01 and 0.10 g kg^?1, respectively.     

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.     

Effects of skin and grilling method on formation of heterocyclic amines in chicken pectoralis superficialis muscle

Mutagenic heterocyclic amines (HAs) originate in processed proteinaceous foods. The effects of the presence of skin (with vs. without) and of grilling method (two plate vs. infrared) on the content of HAs in grilled chicken pectoralis superficialis muscle (temperature, 220 °C) were investigated. HA precursors (creatine, creatinine, free amino acids and carbohydrates) and HAs of these raw and grilled breast muscles were determined. The muscles originated from 24 birds of either sex (provenance Ross; aged 40-45 days). The HA content was determined in homogenates of the upper and lower surface slices of the grilled muscles (T_i = 82 °C). A higher content of total free amino acids was seen for the muscle (27.1 mmol kg⁻¹ raw meat) than for the skin (21.7 mmol kg⁻¹ raw meat). The creatine, creatinine and carbohydrate levels in the skin were below the limits of detection. The contents of creatine (31.8-38.7 mmol kg⁻¹) and creatinine (0.24-0.33 mmol kg⁻¹) in the breast muscle were determined. Relatively high levels were seen for glucose (23 mmol kg⁻¹ raw meat) and fructose (10 mmol kg⁻¹ raw meat) in the muscle, with other sugars present at low levels (<2 mmol kg⁻¹ raw meat). For the chicken muscle grilled on a two-plate grill, the contents of total HAs (PhIP, MeIQx, DiMeIQx, Harman and Norharman) were lower with the skin in place than in the muscle grilled without the skin (3.5 μg kg⁻¹vs. 4.8 μg kg⁻¹). Also, during infrared grilling with the skin, lower amounts of HAs were formed than with grilling on the two-plate grill (2.4 μg kg⁻¹vs. 3.5 μg kg⁻¹). On average, the infrared-grilled samples with skin contained 3-fold more total HAs than similar samples without the skin (2.4 μg kg⁻¹vs. 0.8 μg kg⁻¹), with the highest levels seen for PhIP and MeIQx.     

Mutagenic heterocyclic amine content in thermally processed offal products

Heterocyclic amines (HAs) are potent mutagens formed during heat-processing of proteinaceous food. PhIP is the most ubiquitous and abundant mutagenic HA. In this study several offal products (beef liver, lamb kidney and beef tongue) have been thermally processed and analysed for HAs for the first time. Norharman and harman were the amines most abundant, found at concentrations below 2 ng g⁻¹. PhIP was only formed up to 0.12 ng g⁻¹. Among the rest of HAs analysed, only DMIP, MeIQx and 4,8-DiMeIQx were detectable in cooked kidney and tongue up to 0.25 ng g⁻¹. The influence of cooking additives on HAs formation was evaluated, finding higher levels of norharman and harman, up to 8.87 ng g⁻¹, in liver processed with additives, whereas similar levels of the rest of HAs were found in these samples. The low amounts of HAs found after the prolonged thermal treatments over 200 °C indicates that offal products are among the types of meat that produce lowest exposure to HA.