Heterocyclic Aromatic Amines Research Articles

High-throughput screening of the Saccharomyces cerevisiae genome for 2-amino-3-methylimidazo [4,5-f] quinoline resistance identifies colon cancer-associated genes.

Heterocyclic aromatic amines (HAAs) are potent carcinogenic agents found in charred meats and cigarette smoke. However, few eukaryotic resistance genes have been identified. We used Saccharomyces cerevisiae (budding yeast) to identify genes that confer resistance to 2-amino-3-methylimidazo[4,5-f] quinoline (IQ). CYP1A2 and NAT2 activate IQ to become a mutagenic nitrenium compound. Deletion libraries expressing human CYP1A2 and NAT2 or no human genes were exposed to either 400 or 800 µM IQ for 5 or 10 generations. DNA barcodes were sequenced using the Illumina HiSeq 2500 platform and statistical significance was determined for exactly matched barcodes. We identified 424 ORFs, including 337 genes of known function, in duplicate screens of the "humanized" collection for IQ resistance; resistance was further validated for a select group of 51 genes by growth curves, competitive growth, or trypan blue assays. Screens of the library not expressing human genes identified 143 ORFs conferring resistance to IQ per se. Ribosomal protein and protein modification genes were identified as IQ resistance genes in both the original and "humanized" libraries, while nitrogen metabolism, DNA repair, and growth control genes were also prominent in the "humanized" library. Protein complexes identified included the casein kinase 2 (CK2) and histone chaperone (HIR) complex. Among DNA Repair and checkpoint genes, we identified those that function in postreplication repair (RAD18, UBC13, REV7), base excision repair (NTG1), and checkpoint signaling (CHK1, PSY2). These studies underscore the role of ribosomal protein genes in conferring IQ resistance, and illuminate DNA repair pathways for conferring resistance to activated IQ.

Comprehensive Review of Red Meat Consumption and the Risk of Cancer.

Red and processed meat consumption rates are increasing in the United States. In this review, we present the current evidence that links red meat consumption and cancer development. A literature search was conducted in the PubMed and Google Scholar databases to review red meat consumption and its association with breast cancer and gastrointestinal cancer. Due to the presence of heme iron, which triggers oxidative reactions that eventually result in tumor formation, red meat consumption is strongly associated with the development of breast cancer. Ingestion of red meat increases Helicobacter pylori infections, resulting in enhanced expression of the CagA gene and the secretion of pro-inflammatory cytokines. This is the leading cause of gastric cancer. There is a strong correlation between heterocyclic amines and polycyclic aromatic hydrocarbons in red meat and the development of pancreatic cancer. However, additional research is necessary to confirm this finding. Adult colorectal cancer is caused by the formation of heterocyclic amines and DNA adducts due to the intake of red and processed meats cooked at higher temperatures. The consumption of poultry is associated with a reduced risk of breast and gastrointestinal cancers, but the results are inconsistent. The evidence is strong for the association between red meat and breast cancer and most gastric cancers. The presence of aromatic hydrocarbons, heterocyclic amines, and heme iron in red meat has been found to be behind tumorigenesis. Poultry has been shown to have a low association with cancer, but additional research is needed.

Carboxyl-functionalized covalent organic frameworks for the efficient adsorption of foodborne heterocyclic aromatic amines

The development of sorbents with high sensitivity and specificity for the effective extraction and assessment of carcinogenic heterocyclic aromatic amines (HAAs) in thermally processed foods is of utmost significance for food safety monitoring. Herein, we report the design and synthesis of a carboxyl-functionalized covalent organic framework (COF), TpPa-(COOH)2, through the regulation of carboxyl modification and crystallinity. The resulting flower-like TpPa-(COOH)2 exhibited excellent crystallinity and microporosity in an eclipsed stacking structure. Compared to TpPa, the introduction of carboxyl moieties in TpPa-(COOH)2 provided additional binding sites and significantly enhanced adsorption affinity for the 16 target analytes, despite having a smaller BET surface area. The adsorption of HAAs by TpPa-(COOH)2 followed the pseudo-second-order model and exhibited rapid kinetics (10–30 min). The experimental data demonstrated a strong fit with the Freundlich isotherm model, resulting in a maximum adsorption capacity of HAAs ranging from 1.8 to 155.8 mg/g. Additionally, the presence of interfering compounds only caused a slight reduction in both the equilibrium adsorption capacity and HAAs recovery. Notably, TpPa-(COOH)2 maintained its effective adsorption performance even after three adsorption–desorption cycles. Theoretical calculations indicated that the rapid binding of HAAs to TpPa-(COOH)2 could be attributed to the joint effects of electrostatic interaction, π–π interaction, C–H–π interaction, lone pair–π interaction, and hydrogen bonding. This adsorbent exhibits a notable enhancement in both adsorption capacity and mass transfer rates for the adsorption of HAAs, surpassing the performance of the reported adsorbents. This highlights its substantial potential for the precise detection of HAAs within food systems.

Effect of simultaneous application of antioxidants in oil and in chicken on heterocyclic aromatic amine formation in deep-fat fried chicken breast

This study aimed to estimate the effects of simultaneous application of antioxidants in meat and in oil on heterocyclic aromatic amine (HAA) formation in fried chicken during 40 deep-fat frying cycles. The experiment was carried out by adding Adinandra nitida leaf extract (ANE) (200 mg/100 g) to chicken while adding tea polyphenols (TP) (40 mg/100 g), sesamol (SL) (40 mg/100 g), or rosemary extract (RE) (40 mg/100 g) to soybean oil. It was found that the addition of TP, SL or RE in oil reduced the lipid oxidation and the formation of total HAAs in meats. Adding ANE alone to meat reduced total HAA contents in meats by 11.98%–38.00%; simultaneously adding TP, SL or RE to oil reduced total HAA contents in meats by 33.98%–61.46%, 15.86%–44.94%, and 25.22%–48.01%, respectively, during 40 frying cycles. Pearson correlation analysis revealed significant correlations (all absolute values of correlation coefficients > 0.53) between HAA formation and oxidation indices. This research supplies evidence that adding antioxidants to both meat and oil inhibits HAA formation during deep-fat frying.

Impact of Cumin (Cuminum cyminum) Incorporation on the Generation of Heterocyclic Aromatic Amines in Meatballs

In the current study, the impacts of using cumin (0.5% and 1%, w/w) in beef meatballs on heterocyclic aromatic amines (HAAs) formation and some quality characteristics when cooked at 150 and 250 °C were investigated. It was found that using of cumin at different ratios in beef meatballs showed a significant (p < 0.01) effect on pH, thiobarbituric acid reactive (TBARS) value, and total HAA. The cooking process significantly (p < 0.01) affected the meatballs’ water content, pH, and TBARS values, while the cooking loss and total HAA content of meatballs were significantly (p < 0.01) affected by cooking temperature. It was found that the cumin usage rate in meatballs increased the pH value, while it was found to decrease the TBARS value. As expected, the cooking process was associated with a reduction in water, while it was found to result in an increase in the pH and TBARS values. On the other hand, both cooking temperature and cumin addition to meatballs led to an increase in their total HAA content. Diverse samples exhibited detectable levels of IQx, MeIQx, MeIQ, and PhIP compounds. The presence of MeIQx compound was found in all samples, except for the control group cooked at 150 °C. Additionally, the use of 0.5% and 1% cumin in meatballs cooked at temperature of 250 °C had an inhibitory effect on MeIQx compound. Our results revealed that the incorporation of cumin in the meatballs resulted in an increase in the total HAA content, likely due to its prooxidant effect. However, it was found that the use of cumin at certain rates could reduce the formation of MeIQx compound with an antioxidant effect. However, in this study found that even if 100 g of meatballs with the highest concentration of total HAA were consumed, the maximum HAA exposure limit value (0–15 µg/day) was not exceeded.

Heterocyclic aromatic amines in meat: Formation mechanisms, toxicological implications, occurrence, risk evaluation, and analytical methods

Heterocyclic aromatic amines (HAAs) are detrimental substances can develop during the high-temperature cooking of protein-rich foods, such as meat. They are potent mutagens and carcinogens linked to an increased risk of various cancers. HAAs have complex structures with nitrogen-containing aromatic rings and are formed through chemical reactions between amino acids, creatin(in)e, and sugars during cooking. The formation of HAAs is influenced by various factors, such as food type, cooking temperature, time, cooking method, and technique. HAAs exert their toxicity through mechanisms like DNA adduct formation, oxidative stress, and inflammation. The research on HAAs is important for public health and food safety, leading to risk assessment and management strategies. It has also led to innovative approaches for reducing HAAs formation during cooking and minimizing related health risks. Understanding HAAs' chemistry and formation is crucial for developing effective ways to prevent their occurrence and protect human health. The current review presents an overview about HAAs, their formation pathways, and the factors influencing their formation. Additionally, it reviews their adverse health effects, occurrence, and the analytical methods used for measuring them.

Impact of seed-roasting treatment on polycyclic aromatic hydrocarbons, 3-MCPD esters, heterocyclic amines and volatile components formation in sunflower oil

Seed-roasting is a crucial process conducted to improve the organoleptic and conservative features of oilseeds. In this paper, raw sunflower seeds were roasted at 160, 180 and 200 °C for various times. Three hazards (polycyclic aromatic hydrocarbons, 3-monochloro-1,2-propanediol esters and heterocyclic amines) and volatile components in the corresponding oil extracted from roasted sunflower seeds were analyzed. Polycyclic aromatic hydrocarbons, 3-monochloro-1,2-propanediol esters and heterocyclic amines were measured using HPLC, GC-MS and UPLC-MS, respectively. Volatiles were determined by GC-MS. The results show that the strength of seed-roasting promoted the formation of the three hazard factors. The contents of polycyclic aromatic hydrocarbons, 3-monochloro-1,2-propanediol esters and heterocyclic amines in sunflower oil increased 9.4, 22.1 and 121.6 fold respectively after roasting at 200 °C for 25 min. The main volatiles were aldehydes and terpenes with a greenish and earthy taste. Volatile levels possessing pleasant flavors of floral, roasted and nuts, particularly aldehydes and pyrazines, generally increased with roasting. However, at high intensity roasting, the appearance of furans would bring burnt, bitter, as well as viscosity, resulting in poor sensory for oil. Considering the limitation of the above mentioned hazards established by EU, the optimal roasting condition of sunflower seed was 180–200 °C for 15–20 min.

Effects of volatile organic compounds of smoke from different woods on the heterocyclic amine formation and quality changes in pork patty

This study investigated the effects of smoke derived from cypress (CY), mulberry (MU), metasequoia (ME), pine (PI), and camphor (CA) on the heterocyclic aromatic amines (HAs), flavor, and sensory attributes of smoked pork patty. The results showed that the smoke derived from the five kinds of wood and the flavor of the corresponding smoked meat were classified into three types. Moreover, the smoke of CY and PI, and the smoke of MU and ME can be classified into one category respectively, which significantly improved the flavor of the smoked meat. Both free and protein-bound HAs were detected in smoked meat, while the smoking process significantly increased the HAs content, especially free Norharman (3.26 ng/g in control meat, and 82.24 ng/g in meat smoked with CY). Correlation analysis showed that various volatile organic compounds (VOCs) and HAs were closely associated. Future research should pay attention to the VOCs in smoked meat including vanillin, Close attention should be paid to tridecane and crotonic acid, as well as tetradecane and α-Dehydro-ar-himachalene in smoke, which were consistently correlated with various HAs and may participate in HAs formation. These results may reveal how the smoking process influences the formation of HAs and which factors should be targeted to inhibit HAs in smoked meat products.

One‐Pot Stereoselective Synthesis of 2,3,4‐Unprotected β‐N‐Glycopyranosides from Glycals and Amines

AbstractA one‐pot synthesis of 2,3,4‐unprotected β‐N‐glycopyranosides from glycals and amines with exclusive β‐stereoselectivity under room temperature conditions is reported. This method was achieved via palladium‐catalyzed Tsuji‐Trost amination followed by dihydroxylation directly, tolerating anilines, heterocyclic aromatic amines, and N,O‐dimethylhydroxylamine, especially the reaction of primary amines and glycals has not been reported before. Furthermore, the protocol was applied to modify clinical drugs (prazosin, imiquimod) and construct the analogue of the natural product amphimedoside A.

Nuclear DNA and Mitochondrial Damage of the Cooked Meat Carcinogen 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine in Human Neuroblastoma Cells.

Animal fat and iron-rich diets are risk factors for Parkinson's disease (PD). The heterocyclic aromatic amines (HAAs) harman and norharman are neurotoxicants formed in many foods and beverages, including cooked meats, suggesting a role for red meat in PD. The structurally related carcinogenic HAAs 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-9H-pyrido[2,3-b]indole (AαC) also form in cooked meats. We investigated the cytotoxicity, DNA-damaging potential, and mitochondrial damage of HAAs and their genotoxic HONH-HAA metabolites in galactose-dependent SH-SY5Y cells, a human neuroblastoma cell line relevant for PD-related neurotoxicity. All HAAs and HONH-HAAs induced weak toxicity except HONH-PhIP, which was 1000-fold more potent than the other chemicals. HONH-PhIP DNA adduct formation occurred at 300-fold higher levels than adducts formed with HONH-MeIQx and HONH-AαC, assuming similar cellular uptake rates. PhIP-DNA adduct levels occurred at concentrations as low as 1 nM and were threefold or higher and more persistent in mitochondrial DNA than nuclear DNA. N-Acetyltransferases (NATs), sulfotransferases, and kinases catalyzed PhIP-DNA binding and converted HONH-PhIP to highly reactive ester intermediates. DNA binding assays with cytosolic, mitochondrial, and nuclear fractions of SH-SY5Y fortified with cofactors revealed that cytosolic AcCoA-dependent enzymes, including NAT1, mainly carried out HONH-PhIP bioactivation to form N-acetoxy-PhIP, which binds to DNA. Furthermore, HONH-PHIP and N-acetoxy-PhIP inhibited mitochondrial complex-I, -II, and -III activities in isolated SH-SY5Y mitochondria. Mitochondrial respiratory chain complex dysfunction and DNA damage are major mechanisms in PD pathogenesis. Our data support the possible role of PhIP in PD etiology.

The influence of heat treatment type on the fat component and heterocyclic aromatic amines formation in minced poultry meat products

In this study the influence of heat treatment type on the change in the fatty acid composition, indices and parameters of fat oxidation, the level of heterocyclic amines formation in the chopped poultry ready-to-eat products enriched with ω‑3 fatty acids and an antioxidant complex were studied. The composition of ingredients and recipes of ready-to-eat products are developed with consideration of the medical and biological requirements for the diets of oncological patients. These ready-to-eat products feature some antioxidant substances in their composition that can bind free radicals, and provide for a reduction in the risk of carcinogens formation during the manufacturing process. The heat treatment was run in several ways, also called as modes — cooking in a microwave oven (MW), cooking in a convection oven in the “convection” mode with preliminary short-term roasting, steam cooking. For comparison, the conventional, i. e. not enriched food sample was used as a control one. The introduction of ω‑3 fatty acids into the food formulation made it possible to change the fatty acid composition towards increasing the proportion of polyunsaturated fatty acids (PUFAs). It was found that the profile of fatty acids was influenced by both the ingredients of the product and the type of its heat treatment. The joint use of a PUFA source and a complex of antioxidants made it possible to obtain a ready-to-eat product with a high level of ω‑3; and to ensure the ratio of ω‑6 group acids: ω‑3 ratio amounts to 1–2:1. Heat treatment of enriched semi-finished products by microwave cooking and by steam cooking showed a lesser effect on the change in the content and composition of polyunsaturated fatty acids — the loss of fatty acids was 1.2% and 2.8%, respectively, while in the “convection” cooking mode with preliminary roasting this loss was equal to 3.5%. It was found that the antioxidant complex in the composition of the food product and gentle heat treatment methods cause less lipid peroxidation and the formation of carcinogenic heterocyclic aromatic amines (HAA) during the food manufacturing process.

Probabilistic dietary exposure and carcinogenic risk of heterocyclic aromatic amines formed in the main groups of fast foods: Investigation of different ages and genders

Probabilistic dietary exposure and carcinogenic risk of heterocyclic aromatic amines formed in the main groups of fast foods: Investigation of different ages and genders

Inhibition of the CYP Enzymatic System Responsible of Heterocyclic Amines Bioactivation by an Asclepias subulata Extract.

Asclepias subulata plant extract has previously demonstrated antiproliferative activity and antimutagenicity against heterocyclic aromatic amines (HAAs) commonly found in cooked meat. The objective of this work was to evaluate the in vitro ability of an ethanolic extract from the medicinal plant Asclepias subulata extract (ASE), non-heated and heated (180 °C), to inhibit the activity of CYP1A1 and CYP1A2, which are largely responsible for HAAs bioactivation. Ethoxyresorufin and methoxyresorufin O-dealkylation assays were performed in rat liver microsomes exposed to ASE (0.002-960 µg/mL). ASE exerted an inhibitory effect in a dose-dependent manner. The half inhibitory concentration (IC50) for unheated ASE was 353.6 µg/mL and 75.9 µg/mL for heated ASE in EROD assay. An IC40 value of 288.4 ± 5.8 µg/mL was calculated for non-heated ASE in MROD assay. However, after heat treatment, the IC50 value was 232.1 ± 7.4 µg/mL. Molecular docking of corotoxigenin-3-O-glucopyranoside, one of the main components of ASE, with CYP1A1/2 structure, was performed. Results show that the interaction of corotoxigenin-3-O-glucopyranoside with CYP1A1/2s' α-helices, which are related with the active site and the heme cofactor, may explain the plant extract's inhibitory properties. Results showed that ASE inhibits CYP1A enzymatic subfamily and may potentially act as a chemopreventive agent by inhibiting bioactivation of promutagenic dietary HAAs.

Effects of soy protein and its hydrolysates on the formation of heterocyclic aromatic amines in roasted pork

This study investigated the influence mechanism of soy protein and its hydrolysates (under three different degree of hydrolysis) on formation of heterocyclic aromatic amines (HAAs) formation in roasted pork. The results showed that 7S and its hydrolysates significantly inhibited the formation of quinoxaline HAAs, and the maximum inhibitory rate of MeIQx, 4,8-MeIQx, and IQx was 69%, 79%, and 100%, respectively. However, soy protein and its hydrolysates could promote the formation of pyridine HAAs (PhIP, and DMIP), its content increased significantly with the increase in the degree of hydrolysis of the protein. The content of PhIP increased 41, 54, and 165 times with the addition of SPI, 7S, and 11S at 11% degree of hydrolysis, respectively. In addition, they promoted the formation of β-carboline HAAs (Norharman and Harman), in a manner similar with that of PhIP, especially the 11S group. The inhibitory effect on quinoxaline HAAs was probably correlated with DPPH radical scavenging capacity. Nevertheless, the promotive effect on other HAAs might be related to the high levels of free amino acids and reactive carbonyls. This research may provide recommendation for the application of soy protein in high-temperature meat products.

Carbonyl-trapping by phenolics and the inhibition of the formation of carcinogenic heterocyclic aromatic amines with the structure of aminoimidazoazaarene in beef patties

Carcinogenic heterocyclic aromatic amines (HAAs) with the structure of aminoimidazoazaarene (PhIP, MeIQx, IQ, and MeIQ) are produced by reaction of creatin(in)e, ammonia, and reactive carbonyls (phenylacetaldehyde, acrolein, and crotonaldehyde). In an attempt to provide efficient methodologies for HAA reduction in beef patties, this study: identified phloroglucinol as the most efficient phenolic to reduce HAA formation (76–96% inhibition); isolated and characterized by NMR and MS phloroglucinol/phenylcetaldehyde and phloroglucinol/acrolein adducts; and determined by LC-MS/MS adduct formation in beef patties treated with phloroglucinol. Obtained results suggested that addition of trihydroxyphenols (including phloroglucinol) to beef patties should decrease HAA formation. This was confirmed by both immersing beef patties in apple (or pear) juice before cooking (>90% inhibition) and including wheat bran in patty recipe. All these results confirm the key role of reactive carbonyls in the formation of carcinogenic HAAs and propose carbonyl-trapping as a way for controlling HAA formation in food products.

Effect of Chemical Refining on the Reduction of β-Carboline Content in Sesame Seed Oil.

β-carbolines (harman and norharman) are potentially mutagenic and have been reported in some vegetable oils. Sesame seed oil is obtained from roasted sesame seeds. During sesame oil processing, roasting is the key procedure to aroma enhancement, in which β-carbolines are produced. Pressed sesame seed oils cover most market share, while leaching solvents are used to extract oils from the pressed sesame cake to improve the utilization of the raw materials. β-carbolines are nonpolar heterocyclic aromatic amines with good solubility in leaching solvents (n-hexane); therefore, the β-carbolines in sesame cake migrated to the leaching sesame seed oil. The refining procedures are indispensable for leaching sesame seed oil, in which some small molecules can be reduced. Thus, the critical aim is to evaluate the changes in β-carboline content during the refining of leaching sesame seed oil and the key process steps for the removal of β-carbolines. In this work, the levels of β-carbolines (harman and norharman) in sesame seed oil during chemical refining processes (degumming, deacidification, bleaching and deodorization) have been determined using solid phase extraction and high performance liquid chromatography-mass spectrometry (LC-MS). The results indicated that in the entire refining process, the levels of total β-carbolines greatly decreased, and the adsorption decolorization was the most effective process in reducing β-carbolines, which might be related to the adsorbent used in the decolorization process. In addition, the effects of adsorbent type, adsorbent dosage and blended adsorbent on β-carbolines in sesame seed oil during the decolorization process were investigated. It was concluded that oil refining can not only improve the quality of sesame seed oil, but also reduce most of the harmful β-carbolines.

Evaluation of Chinese Prickly Ash and Cinnamon to Mitigate Heterocyclic Aromatic Amines in Superheated Steam-Light Wave Roasted Lamb Meat Patties Using QuEChERS Method Coupled with UPLC-MS/MS

Chinese prickly ash and cinnamon contain many antioxidants, which scavenge free radicals and can reduce many harmful compounds, such as heterocyclic aromatic amines (HAAs). Modern technologies used for cooking, such as the use of superheated steam roasting, are beneficial in decreasing the development of HAAs. The current study was based on the use of these two spices in roasted lamb patties to mitigate the formation of HAAs in superheated steam roasted patties. Results exhibited significant differences (p < 0.05) in the content of both polar and non-polar HAAs as compared to control patties. In cinnamon roasted patties, polar HAAs were reduced from 23.76 to 10.56 ng g−1, and non-polar HAAs were reduced from 21.34 to 15.47 ng g−1. In Chinese prickly ash patties, polar and non-polar HAAs were 43.60 ng g−1 and 35.74 ng g−1, respectively. Similarly, cinnamon-treated patties showed a significantly higher (p < 0.05) reduction in polar HAAs (23.52 to 12.41 ng g−1) than non-polar (16.08 to 9.51 ng g−1) at concentrations of 0.5–1.5%, respectively, as compared to the control, with 45.81 ng g−1 polar and 35.09 ng g−1 non-polar HAAs. The polar HAAs tested were PhIP, DMIP, IQx, and 8-MeIQx, while the non-polar were harman and norharman. Both spices and superheated steam controlled HAAs to a significant level in lamb meat patties.

A Short Review on Carcinogenicity

Humans are exposed to a variety of different and persistent DNA-damaging agents, some of which have been identified as carcinogens. DNA damage can occur from exposure to exogenous agents, but damage from endogenous processes is more common. That is, epidemiological studies of migrant populations from low-cancer-risk areas to high-cancer-incidence countries suggest the role of environmental factors and/or lifestyle as important players in the etiology of cancer. As a result, it can be assumed that carcinogens found in the environment or our diet are to blame. Carcinogen exposure is associated with various forms of DNA damage, including single-strand breaks, double-strand breaks, chemical DNA cross-links, oxidative stress, and DNA-DNA or DNA-protein breaks. This review focuses on DNA damage caused by the following carcinogens: polycyclic aromatic hydrocarbons, heterocyclic aromatic amines, mycotoxins, ultraviolet light, ionizing radiation, aristolochic acid, nitrosamines, and particulate matter. In addition, we discuss several cancers for which molecular epidemiological evidence suggests that these agents are etiological risk factors. The complex role that carcinogens play in the pathophysiology of cancer development remains unclear, but DNA damage remains central to this process.

The impact of temperature-controlled smoldering smoking on polycyclic aromatic hydrocarbons and heterocyclic amines contents in Frankfurter-type sausages

The impact of temperature-controlled smoldering smoking conditions on the accumulations of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HAs) in Frankfurter-type sausages was investigated. Depending on the temperature, smoking can be divided into two phases: an unstable pyrolysis stage (≈ 200 s) and a stable pyrolysis stage (>200 s), which had different effects on hazardous substances contents. The unstable pyrolysis stage, which contributed 66.9 ∼ 89.6% of PAH accumulations by comparing with sausages smoked for 15 min, has significant impact on high PAH residues. By contrast, the contents of HAs showed steady increase trends with smoking time. Few types of free-HAs with low concentrations (3.05 ∼ 22.9 ng/g DW), but more types of bound-HAs with much higher levels (10.8 ∼ 396 ng/g DW) were found. In addition, the formation of some HAs followed the first-order reaction model. However, the detailed formation mechanisms of PAHs and HAs under temperature-controlled smoldering smoking conditions remain to be studied.

New heterocyclic azo-disperse dyes; their synthesis, characterization, application, photo physical properties and solvatochromic studies

In current research exploration, novel heterocyclic disperse dyes were synthesized, using 8-aminonaphthalen-2-ol as a coupling component and different heterocyclic aromatic amines e.g. sulfadiazine, sulfamethazine, sulfathiazole sodium salt, 2-aminobenzothiazole and 2-amino-6-methoxybenzothiazol as a diazonium component. Different analytical techniques including FT-IR, 1H-NMR, UV-Visible, FAB-LRMS and FAB-HRMS were used for the structural elucidation of the synthesized disperse dyes. The melting point of the synthesized compounds were also determined. The solvatochromism of these dyes was examined in six organic solvents possessing different polarity and the sensitivity of the absorption maxima (λmax) to acidic and basic pH were evaluated in methanol. Bathochromic shift was observed with increase in solvent polarity and under acidic pH. The fluorescence studies all the dyes were performed in four different solvents. The obtained chromophores were applied on polyester fabric observing different parameters like build-up profile, perspiration fastness, rubbing fastness, wash fastness, light fastness and sublimation fastness. All the dyes exhibited good to very good color yield and excellent fastness properties.