Effects and mechanisms of using "clean" smoke particles in the smoking process on the formation of ß-carboline heterocyclic amines (ß-CHAs) in smoked meat patties.

ß-Carboline heterocyclic amines (ß-CHAs), known for their synergistic neurotoxic and carcinogenic effects, are predominantly produced by humans through cigarette smoke and food and are found particularly in meats cooked at high temperatures. Few studies have explored the differences in the mechanisms of accumulation of ß-CHAs in smoked meat and meat processed at high temperatures. In this research, the concentration of ß-CHAs in smoked meats prepared using a variety of wood materials was measured using LCMS/MS. Additionally, key volatile organic compound markers associated with ß-CHAs accumulation in smoke were identified through GCMS and multivariate statistical analysis and subsequently confirmed in a chemical simulation system. Three types of strainers, each with a distinct aperture size, were used to assess the efficacy of particle filtration in reducing ß-CHAs levels in smoked meat. The findings indicated that smoke exposure indeed increases the ß-CHAs content of meat. However, only the strainer capable of filtering PM2.5-sized particles reduced the amount of ß-CHAs present compared to the control group. In contrast, strainers with larger pore sizes facilitated excessive accumulation of ß-CHAs. The presence of aldehydes such as 1 H-pyrrole-2-carboxaldehyde, 5-methylfurfural, benzaldehyde, furfural, and nonanal exhibited a positive correlation with the accumulation of ß-CHAs. Conversely, phenolic compounds, including 2-methoxy-4-vinylphenol, 2-methoxy-5-methylphenol, p-cresol, phenol, 2-methoxy-4-(1-propenyl)-, (Z)-, phenol, 3-ethyl-, and phenol, 4-ethyl-2-methoxy-, showed a negative correlation. Thus, filters made from chelated carbonyl trap materials both chemically and physically disrupt the buildup of ß-CHAs in smoked meats. The use of this approach will not only improve the quality of these products but will also contribute to decreasing the amount of inhalation pollutants released into the environment.

Effect of Chinese quince proanthocyanidins on the inhibition of heterocyclic amines and quality of fried chicken meatballs and tofu.

Heterocyclic amines (HCAs) have potential carcinogenic and mutagenic activity and are generated in cooked protein-rich foods. Adding proanthocyanidins (PAs) to these foods before frying is an effective way to reduce HCAs. In this study, polymeric PAs (PPA) and ultrasound-assisted acid-catalyzed/catechin nucleophilic depolymerized PAs (UAPA, a type of oligomeric PA) were prepared from Chinese quince fruits (CQF). Different levels of PPA and UAPA (0.05%, 0.1%, and 0.15%) were added to chicken meatballs and tofu; then these foods were fried, and the content of HCAs in them after frying was investigated. The results showed that PPA and, particularly, UAPA significantly inhibited the formation of HCAs in fried meatballs and tofu, and this inhibition was dose-dependent. The inhibition of HCAs by both PPA and UAPA was stronger in the chicken meatballs than in fried tofu. The level of total HCAs was significantly reduced by 57.84% (from 11.93 to 5.03 ng/g) after treatment of meatballs with 0.15% UAPA, with inhibition rates of 78.94%, 50.37%, and 17.81% for norharman, harman, and 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), respectively. Of note, there was a negative correlation between water, lipid, protein, creatine, and glucose content and HCA content in the crust, interior, and whole (crust-plus-interior) measurements of all fried samples. Interestingly, PPA and UAPA were found more effective in inhibiting HCAs in the exterior crust than in the interior of the fried chicken meatballs. These results provide evidence that further studies on the reduction of the formation of harmful HCAs in fried foods by adding CQF PAs could be valuable to the fried food industry. PRACTICAL APPLICATION: Chinese quince proanthocyanidins treatments significantly inhibited the generation of heterocyclic amines (HCAs) in chicken meatballs and tofu when deep-fried. These results suggest that Chinese quince proanthocyanidins can be used as natural food additive for reducing HCAs in fried foods, laying the foundation for using Chinese quince fruit proanthocyanidins for HCA inhibition in the food industry.

The magnetic layered double hydroxide/zeolitic imidazolate framework-8 nanocomposite coupled with HPLC-MS/MS for the detection of heterocyclic aromatic amines in thermally processed meat.

In this research, a novel magnetic nanocomposite (Fe3O4@Zn/Al-LABSA-LDH/ZIF-8) was synthesized using Fe3O4 as the magnetic core, layered double hydroxide (LDH) with linear alkylbenzene sulfonic acid (LABSA) intercalation and zeolitic imidazolate framework-8 (ZIF-8) as the shell. Benefiting from the intercalation of LABSA into LDH combined with ZIF-8, the multiple interactions, including π-π stacking, hydrogen bonding, and electrostatic interactions, conferred high selectivity and good extraction capability to the material towards heterocyclic aromatic amines (HAAs). Fe3O4@Zn/Al-LABSA-LDH@ZIF-8 was used as an adsorbent for magnetic solid-phase extraction (MSPE) to enrich HAAs in thermally processed meat samples, followed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) detection. The method exhibited a low detection limit (0.021-0.221 ng/g), good linearity (R2 ≥ 0.9999), high precision (RSD < 7.2 %), and satisfactory sample recovery (89.7 % -107.5 %). This research provides a promising approach for developing novel adsorbents in sample preparation and improving analytical performance.

Heterocyclic fluorescent Schiff base chemosensors for the detection of Fe(III) and Cu(II) ions.

Two new Schiff bases were synthesized from 1-(2,4-dihydroxyphenyl)ethanone and pyridine derivatives. Both compounds were characterized using infrared, UV-Vis., 1H NMR, 13C NMR and mass spectral studies. Density functional theory (DFT) calculations were performed for both the Schiff bases with 6-31G(d, p) as the basis set. Vibrational frequencies calculated using the theoretical method were in good agreement with the experimental values. Both the Schiff bases were highly fluorescent in nature. The cation-recognizing profile of the compounds was investigated in aqueous methanol medium. The Schiff base 4-(1-(pyridin-4-ylimino)ethyl)benzene-1,3-diol (PYEB) was found to interact with Fe(III) and Cu(II) ions, whereas the Schiff base 4,4'-((pyridine-2,3-diylbis(azanylylidene))bis(ethan-1-yl-1-ylidene))bis(benzene-1,3-diol) (PDEB) was found to detect Cu(II) ions. The mechanism of recognition was established as combined excited state intramolecular proton transfer (ESIPT)-chelation-enhanced fluorescence (CHEF) effect and chelation-enhanced quenching (CHEQ) process for the detection of Fe(III) and Cu(II) ions, respectively. The stability constant of the metal complexes formed during the sensing process was determined. The limit of detection for Fe(III) and Cu(II) ions with respect to Schiff base PYEB was found to be 1.64 × 10-6 and 2.16 × 10-7 M, respectively. With respect to Schiff base PDEB, the limit of detection for Cu(II) ion was found to be 4.54 × 10-4 M. The Cu(II) ion sensing property of the Schiff base PDEB was applied in bioimaging studies for the detection of HeLa cells.

Development of a UPLC-MS/MS-based method for simultaneous determination of advanced glycation end products and heterocyclic amines in stewed meat products.

A novel analytical strategy was proposed to simultaneously quantify two advanced glycation end products (AGEs) including Nε-(Carboxymethyl)lysine (CML), Nε-(Carboxyethyl)lysine (CEL) and eight heterocyclic amines (HAs) including IQ, MeIQ, MeIQx, 4,8-DiMeIQx, 7,8-DiMeIQx, PhIP, Harman, and Norharman. The procedure was based on a two-step extraction, solid phase extraction (SPE) purification followed by ultra performance liquid chromatography tandem mass spectrometry. The established method showed a good linearity (R2 ≥ 0.9950), rapid processing time (8 min per sample), satisfactory recoveries (matrix spiked recoveries range from 72.2% to 119.6%) and precision (intra-day and inter-day RSDs were <19.3%). The limit of quantification (LOQ) and limit of detection (LOD) resulted to be between 0.05-15 ng/g and 0.2-50 ng/g, respectively. The validated technique was further applied to determine HAs and AGEs in eight stewed meat product samples consumed in Shanghai, with the amount of HAs and AGEs ranging from 2.851 to 18.289 ng/g and 118.158-543.493 ng/g, respectively.

Effects of seasoning addition and cooking conditions on the formation of free and protein-bound heterocyclic amines and advanced glycation end products in braised lamb.

The accumulation of heterocyclic amines (HAs) and advanced glycation end products (AGEs) in thermally processed meats has been arising safety concerns. The effects of cooking conditions and seasoning addition on the formation of HAs and AGEs in Chinese traditional braised lamb were investigated by UPLC-MS/MS analysis. Soy sauce significantly increased the formation of HAs and AGEs, among which light soy sauce had the greatest promoting effect (69.45-15300.62 %). Conversely, spices inhibited HAs and AGEs formation, the inhibition rate of free HAs and AGEs reached 22.06-34.72 % when using 70 % ethanol extract. Hot blanching treatment and adding soy sauce and spices at a later stage could significantly suppress HAs and AGEs production. Flavonoids, including galangin, hesperidin, narirutin, etc., were identified as key effectors in spices. These findings help to promote awareness of the formation of HAs and AGEs in braised lamb and provide valuable insights for optimizing processing techniques to minimize their production.

Comparing application methods of reishi mushroom (Ganoderma lucidum) extract in deep-fried meatballs: impact on heterocyclic aromatic amine formation.

BACKGROUND: The present research was conducted to investigate the impact of reishi mushroom extract (RME) on the formation of heterocyclic aromatic amines (HAAs) in meatballs. Sample preparations involved applying RME using either the spreading or addition method, with varying concentrations (0%, 0.25%, 0.5%, and 1% of RME), followed by deep-frying at temperatures of 150 and 190 °C for 3 min. RESULTS: The types and levels of HAAs varied based on the frying temperature, method of extract application, and the extract concentration. Notably, total HAA contents increased with rising the frying temperature (P < 0.01) and varied from undetectable levels to 4.91 ng g-1 across all analyzed meatballs. The addition method was more effective than the spreading method (P < 0.01), and among the concentrations tested 0.25% RME exhibited the highest efficacy in reducing total HAAs (P < 0.05). Furthermore, the addition method inhibited lipid oxidation more efficiently compared to the surface spreading method (P < 0.05). CONCLUSION: This study demonstrated that RME had mitigating effects on HAAs depending on the concentration and frying conditions in deep-fried meatball samples. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

One Pot Synthesis of Nanofiber-Coated Magnetic Composites as Magnetic Dispersive Solid-Phase Extraction Adsorbents for Rapid Determination of Tetracyclines in Aquatic Food Products.

A magnetic adsorbent based on a C-nanofiber (Fe3O4@C-NFs) nanocomposite was synthesized using a simple one-pot co-precipitation method. The characterized results showed that the obtained C-nanofiber-coated magnetic nanoparticles had many attractive features such as a large specific surface area and a highly interwoven and branched mesoporous structure, as well as distinguished magnetism. The nanocomposite was then used as an adsorbent in the magnetic solid phase extraction (MSPE) of four typical tetracyclines (oxytetracycline, tetracycline, chlortetracycline, and doxycycline) in aquatic products. The TCs in the extract were determined using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Experimental variables of MSPE, including the sorbent amount, pH condition, adsorption and desorption time, and desorption solvent, were investigated and optimized systematically. The method validation indicated that the developed method showed good linearity (R2 > 0.995) in the range of 1.0-200 ng/mL. The average recoveries at the spiked levels ranged from 90.7% to 102.7% with intra-day and inter-day relative standard deviations (RSDs, n = 6) ranging from 3.72% to 8.17% and 4.20% to 9.69%, respectively. The limit of detection (LOD) and limit of quantification (LOQ) for the four kinds of TCs were 0.7 µg/kg and 2.0 µg/kg, respectively. Finally, MSPE based on C-nanofiber-coated magnetic nanoparticles was successfully applied to TC analysis in real aquatic products (grass carp, large yellow croaker, snakehead, mandarin fish, Penaeus vannamei, swimming crab, etc.). Compared with traditional extraction methods, the proposed method for TC analysis in aquatic products is more sensitive, effective, recyclable, and environmentally friendly.

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 ß-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.

Non-thermal plasma activated peroxide and percarbonate for tetracycline and oxytetracycline degradation: Synergistic performance, degradation pathways, and toxicity evaluation.

Tetracycline (TC) and Oxytetracycline (OTC) are common antibiotics increasingly detected in the environment, posing a potential risk to human and aquatic lives. Although conventional methods such as adsorption and photocatalysis are used for the degradation of TC and OTC, they are inefficient in removal efficiency, energy yield, and toxic byproduct generation. Herein, a falling-film dielectric barrier discharge (DBD) reactor coupled with environmentally friendly oxidants (hydrogen peroxide (HPO), sodium percarbonate (SPC), and HPO + SPC) was applied, and the treatment efficiency of TC and OTC was investigated. Experimental results showed that moderate addition of the HPO and SPC exhibited a synergistic effect (SF > 2), significantly improving the antibiotic removal ratio, total organic removal ratio (TOC), and energy yield by more than 50%, 52%, and 180%, respectively. After 10 min of DBD treatment, the introduction of 0.2 mM SPC led to a 100% antibiotic removal ratio and a TOC removal of 53.4% and 61.2% for 200 mg/L TC and 200 mg/L OTC, respectively. Also, 1 mM HPO dosage led to 100% antibiotic removal ratios after 10 min of DBD treatment and a TOC removal of 62.4% and 71.9% for 200 mg/L TC and 200 mg/L OTC, respectively. However, the DBD + HPO + SPC treatment method had a detrimental effect on the performance of the DBD reactor. After 10 min of DBD plasma discharge, the removal ratios for TC and OTC were 80.8% and 84.1%, respectively, when 0.5 mM HPO + 0.5 mM SPC was added. Moreover, principal component and hierarchical cluster analysis confirmed the differences between the treatment methods. Furthermore, the concentration of oxidant-induced in-situ generated ozone and hydrogen peroxide were quantitatively determined, and their indispensable roles during the degradation process were established via radical scavenger tests. Finally, the synergetic antibiotic degradation mechanisms and pathways were proposed, and the toxicities of the intermediate byproducts were evaluated.

The enhance mechanism of DOM on tetracyclines degradation by electrochemical technology: A improvement of treatment processes.

Tetracyclines (TC) is a typical broad-spectrum antimicrobial agent, and excessive use of TC can lead to a large accumulation of residual tetracycline in water. DOM is organic substances that can pass through the 0.45 µm filter. While dissolved organic matter (DOM) is one of the most significant substances in water, which has an important effect on water treatment. In this study, ultraviolet and visible spectrophotometry (UV-Vis) is applied to explore DOM to the effect of the electrochemical degradation. Three-dimension excitation emission matrix fluorescence spectroscopy (3D-EEM) is used to identify the component variation of DOM after the electrochemical oxidation (EO). Liquid chromatograph mass spectrometer (LC-MS) is used to confirm the degradation pathway of TC whether spontaneous or electrochemical oxidation. High performance liquid chromatography (HPLC) suggests the ROS production by DOM in the electrochemical oxidation under different conditions. Results show that DOM can promote the degradation of TC in the electrochemical oxidation. Tailwater DOM containssubstances can produce persistent free radicals, which can promote the degradation under light and dark conditions, natural source DOM can produce more free radicals under light. Therefore, TC wastewater should be added tailwater to promote the degradation of TC before the further water treatment. Otherwise, TC can be degraded to differentpathways (light, electricity, and degrade spontaneously). This study provides a significant idea for practical water treatment of tetracyclines, and promotes the practical application of electrochemical technology.

Quantification of hetero-cyclic amines from different categories of braised beef by optimized UPLC-TQ-XS/ESI method.

This research work has developed and optimized a sensitive analytical method for separation and quantification of heterocyclic amines (HCAs) mainly including PhIP, Harman, Norharman, IQ, MeIQ, AαC, MeAαC and Trp-P-2 by optimizing UPLC-TQ-XS using electrospray ionization source (ESI+) on ACQUITY UPLC® BEH C18 column in <7 min, from braised beef sample matrix. Meanwhile, modified HCAs extraction by modifying QuEChERS (quick, easy, cheap, efficient, rugged and safe) technique and revisited with solid phase extraction (SPE) for HCAs purification, instead using traditional QuEChERS salts. Moreover, optimized pH conditions of HCA extracts before purification, for better extraction recoveries. Furthermore, this method was validated in terms of method validation parameters. Lastly, simulation of real braised beef model provided the minimum formation of HCAs by optimizing cooking parameters and precursors in a cooking system. Therefore, this method could be applied simultaneously on braised beef matrix either marketed or home cooked for HCAs analysis.

Sensory acceptability of antioxidant-based formulations dedicated to mitigate heterocyclic aromatic amines in cooked meat.

In a previous work, we studied the inhibition of heterocyclic aromatic amine formation by natural ingredients rich in antioxidants: caper, oregano, wine and green tea. This present work aimed to assess the sensory impact of the addition of these ingredients in ground beef patties. The best liked formulations were determined by a hedonic scoring. Caper and oregano were not significantly different from the standard, the most appreciated, due to their congruency with cooked meat. Direct dissimilarity assessment was performed to evaluate the overall, gustative and odor differences between formulations. Olfactive differences were evidenced as key drivers of these differences. Standard and caper were close while oregano was found significantly different from them. A fast sensory profiling permitted to evidence that aromatic plant note was discriminant for oregano formulation. Gas chromatography-mass spectrometry/multibooth olfactometry identified the distinctive odor-active compounds of the formulations as pyrazines and sulfide for oregano formulation and ester for caper formulation.

Inhibitory and antioxidative capacity of nutmeg extracts on reduction of lipid oxidation and heterocyclic amines in pan-roasted beef patties.

Identification and inhibition of mutagenic and carcinogenic heterocyclic amines (HCAs) from pan-roasted beef patties were performed by adding (0.02%) tertiary butyl hydroquinone (TBHQ) and (0.05%) ethanol-extracted nutmeg (ENE) using HPLC and principal component analysis. Ten HCAs, including six polar and four non-polar, were assessed. The addition of (0.05%) ENE significantly (P < 0.05) reduced the cooking loss and shrinkage of patties during cooking and reduced the total formation HCAs by 73.97%, which proved the significant (P < 0.05) inhibitory effect as a natural antioxidant against lipid oxidation and HCA formation compared to TBHQ. The DPPH radical-scavenging activity, total phenolic content, and available active metabolites of ENE were estimated. Furthermore, a positive correlation was observed between pH, level of thiobarbituric acid reactive substances, and HCA formation in both the groups. TBHQ and ENE were significant HCAs inhibitors (P < 0.001), but ENE showed resilient oxidative stability during refrigeration storage. Therefore, ENE can be used to reduce HCAs formation in pan-roasted beef patties.

Effects of emulsifiers on heterocyclic amine formation and water distribution in roasted chicken patties.

The present study aimed to investigate the effects of five emulsifiers, including DATEM, DMG, PL, SDS, and SPP, on HA formation in chemical models and roasted chicken patties. UPLC-MS analysis showed that DMG and SPP were the most promising among them. In particular, at 0.15-0.9% (w/w) in roasted chicken patties, they effectively reduced the contents of PhIP (21-43%), MeIQx (26-50%) and 4,8-DiMeIQx (16-43%) relative to the control, whereas DATEM, PL and SDS promoted their formation. Low-Field Nuclear Magnetic Resonance and Magnetic Resonance Imaging analysis revealed that the inhibitory effect of SPP and DMG was partly mediated through their capability to help retain water in the macromolecular structures of the muscle tissue. This favorable effect was also supported by the significantly improved adhesiveness of the SPP and DMG samples relative to other samples. These findings suggest that SPP and DMG are effective additives for attenuation of HA contents in meat-based products.

Raw to charred: Changes of precursors and intermediates and their correlation with heterocyclic amines formation in grilled lamb.

This work aimed to investigate the changes and correlations of precursors, intermediates and heterocyclic amines (HCAs) in lamb during charcoal grilling. 28 chemical compounds were detected by high-performance liquid chromatography and gas chromatography-mass spectrometry in grilled lamb from raw to charred. Results demonstrated the types and contents of HCAs were increased during grilling, of which 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP) was dominant and accounted for 61% at the end of grilling (42 min). Glucose and creatine (P < 0.05) decreased with grilling time, creatinine (P < 0.05) and total free amino acid increased. The types and contents of four intermediates (formaldehyde, acetaldehyde, phenylacetaldehyde, 2,5-dimethylpyrazine) increased during grilling. Glucose, creatine, creatinine, ten free amino acids and four intermediates showed significant correlation to HCAs. Also, the ratios of four precursors were significantly correlated with HCAs (P < 0.05), besides creatine/glucose ratio. These results suggested that the time of charcoal grilling should not exceed 14 min at 145 °C in order to reduce the formation of harmful compounds in lamb meat.

Electrophilic components from Xiaoheiyao (rhizomes of Inula nervosa Wall.) alleviate the production of heterocyclic aromatic amines via creatinine inhibition.

Xiaoheiyao is the rhizome of Inula nervosa Wall., a traditional spice and medicinal herb in China. In this study, the creatinine inhibitor from Xiaoheiyao extract and also the effects and mechanism on the production of heterocyclic aromatic amines (HAAs) were investigated. Xiaoheiyao extract inhibited the total contents of seven detected HAAs in grilled beef patties, particularly aminoimidazole-azaarenes (AIAs) in a dose-dependent manner, reaching a maximum inhibition rate of 62% for total HAAs and 73% for AIAs. The most effective subfraction of Xiaoheiyao extract (IER80) contained abundant potential creatinine inhibitors, as revealed by immobilized creatinine probe, HPLC and UPLC-MS/MS analyses. Moreover, electrophilic p-coumaric acid derivatives were discovered from IER80 by feature based molecular networking. p-Coumaric acid was demonstrated to inhibit the contents of total HAAs and AIAs in grilled beef patties and model system. Quantitative analyses of the precursor and intermediates of AIAs in model system revealed that p-coumaric acid mainly affected the generation of AIAs by inhibiting creatinine.

Heterocyclic aromatic amines in roasted chicken: Formation and prediction based on heating temperature and time.

The effects of chicken roasting temperature and time on the production of heterocyclic aromatic amines (HAAs) were investigated and an HAA prediction model based on heating conditions was established. Generally, the HAA content was significantly affected by the heating conditions in the roast chicken. Transportation of precursors from meat to skin, exposure of skin to high temperatures, and fat oxidation in the skin may result in higher HAAs than meat. Principal component analysis (PCA) showed that the effect of relatively high temperatures and long roasting times on HAAs was stronger than that of lower temperatures and shorter roasting times. In the prediction of HAA production, all regression correlation coefficient (R) values were close to one. The errors of 15 samples of experimental and predictive data were close to zero. Based on the results, backpropagation-artificial neural network (BP-ANN) has a high potential for predicting the production of HAAs under heating conditions.

Propolis extract reduces heterocyclic aromatic amine formation in chicken thigh meat.

1. The objective of the present study was to examine the effect of propolis extract on reducing the formation of carcinogenic/mutagenic heterocyclic aromatic amines (HAAs), thereby minimising dietary exposure in human consumers.2. Chicken thigh meat samples were marinated with various concentrations (0%, 0.25%, 0.5% and 1%) of propolis extract, and cooked in a pan at 150°C or 200°C. Proximate composition, pH, lipid oxidation, creatine, creatinine content and twelve HAA levels of samples were analysed.3. Varying levels of IQx (≤35.44 ng/g), MeIQx (≤0.58 ng/g), MeIQ (≤1.60 ng/g), 7,8-DiMeIQx (≤0.83 ng/g), 4,8-DiMeIQx (≤0.75 ng/g), Harman (≤5.54 ng/g), Trp-P-2 (≤1.77 ng/g), PhIP (≤1.61 ng/g) and AαC (≤0.93 ng/g) were quantified in control samples. Total HAA levels ranged between 2.83 and 47.26 ng/g across all samples. Propolis extract decreased the levels of total HAAs by 41.2-89.4% and 49.4-91.4% at 150°C and 200°C, respectively.4. The results demonstrated that propolis extract marination might be an effective strategy to reduce the dietary exposure of HAAs via mitigating their formation in chicken thigh meat.

Development and optimization of an ultra-fast microextraction followed by HPLC-UV of tetracycline residues in milk products.

The present study developed a new ultra-fast microextraction (within 8 min) with acetonitrile followed by gradient reversed-phase HPLC-UV method to determinate six tetracyclines simultaneously in various milk products with HPLC analysis time of 9 min. Chromatographic separations were achieved with a phenomenex™ Synergi 4 µm Fusion-RP (150 × 4.60 mm) column at 220 nm, using acetonitrile/KH2PO4 buffer (4 mmol·L-1, pH 2.5) as mobile phase. The HPLC method showed excellent peak resolutions (3.3-8.8) and peak symmetry (0.99-1.11) inspite of short analysis time. The extraction rates from milk products showed consistently very good values over all tetracyclines (milk 80.58 ± 5.39 %, yoghurt 82.61 ± 5.63 %, cream cheese 80.13 ± 6.32 %, buttermilk 81.07 ± 6.49 %, kefir 79.69 ± 6.51 %, skyr 78.12 ± 5.22 %, quark 65.37 ± 4.72 %). The optimized method was found to be specific, reproducible, robust. This study combines for the first time a fast, cheap quantification of six tetracyclines via HPLC-UV with a reliable microextraction applicable to various milk products using only standard laboratory equipment.