Inhibition of Heterocyclic Aromatic Amines in Pork Chops Using Complex Marinades with Natural Antioxidants

Five marinades were developed using natural antioxidants. Based on a consumer test of the appearance, three marinades were chosen for further investigation: an oregano, an acerola and a Dijon marinade, the Dijon marinade containing acerola, sumac and oregano. A barbecue and a sumac marinade were not included in the further study. In a home use test, consumers barbecued pork chops with the three marinades. Most of the consumers preferred the oregano and the Dijon marinade, while the acerola marinade was less liked. After controlled cooking using both direct and indirect heat to a core temperature of 65°C and 80°C, the content of the heterocyclic aromatic amines (HCA) PhiP, MeIQx, DiMeIQx, Harman and Norharman was analysed. All of the marinades reduced the content of MeIQx and DiMeIQx, although only with indirect heat, while PhiP was reduced using both grilling methods. Surprisingly, in particular the content of Harman—and to a lesser extent Norhaman—was very high in the Dijon-marinated chops. The results demonstrated that it was possible to develop well-liked marinades that can reduce the formation of selected HCAs.

CATALYTIC LABELLING AND ~3H NMR ANALYSES OF SOME AROMATIC AND HETEROCYCLIC COMPOUNDS

This paper described the ~3H NMR determination of the positions and content of 24 tritium labeled aromatic and heterocyclic compounds prepared by catalytic tritiation derivatives, pyrrole, 1,2,4-triazole, thiazole, benzothiazole, purine and derivatives, indole, indanol, piperidine and derivative, diphenylamine, N- phenylanthranilic acid, 8- OH- quinoline, naphthol, diphenylether have been tritiated by catalytic exchange method using tritiated water and platinum catalyst (from the dioxide and sodium borohydride), and the pattern of labelling has been assigned by ~3H NMR spectroscopy. The results show that this exchange process can give general labelling compounds at various time and temperatures. For 4-Br-diphenylether, Raney nickel was used instead of Pt as a catalyst.

Synthesis,Characterization and Protonation Study of Novel Poly(thioether imide)s based on Aromatic Heterocyclic Diimide

Novel poly（thioether imide）s were synthesized by 2,5-dimercapto-l,3,4-thiadiazole, and aromatic heterocyclic chlorodiimids through nucleophilic!substitution reaction as alkali catalysts were presented. The poly（thioether imide）s exhibited good thermal property. The glass transition temperatures of polymers were around 373 ℃, and 10% weight loss temperatures were in the range of 450-500 ℃ in nitrogen/air atmosphere. Meanwhile, the chloroform dilute solutions of these polYmers could show strong UV-vis absorption peaks at about 289 nm. After being protonated by inorganic acids （HC1）, the new shoulder absorption peaks were observed at 350 nm. The PL absorption bands of polymer solutions were in the region of 350-550 nm, which showed the green-yellow fluorescence.

The role of flavonoids in mitigating food originated heterocyclic aromatic amines that concerns human wellness

Meat products are an important part in our daily diet,providing valuable nutrients for the human body.However,heating processes cause the meat to become more appetizing with changes in texture,appearance,flavor,and chemical properties by the altering of protein structure and other ingredients.As one kind of cooking-induced contaminants,heterocyclic aromatic amines(HAAs)are widely present in protein aceous food products with strong carcinogenic and mutagenic properties.In order to promote the safety of traditional meat products,this review focused on the formation,metabolism,biological monitoring and inhibitory mechanism of HAA.An overview of the formation pathways,hazards,and control methods of HAAs during food processing in recent years was studied,aiming to provide some valuable information for exploring effective methods to inhibit the production of associated hazards during food processing.Systematic selection of different types of flavonoids to explore their effects on the formation of HAAs in an actual barbecue system can provide theoretical reference for effectively controlling the formation of HAAs and reducing their harm to human health.

HETEROCYCLIC SCHIFF BASE NEODYMIUM COMPLEX AS CATALYST FOR RING-OPENING POLYMERIZATION OF ε-CAPROLACTONE

An aromatic heterocyclic Schiff base neodymium complex bearing thiazole was synthesized and its activity in the ring-opening polymerization ofε-caprolactone(CL)was examined.The conditions of the CL/Nd molar ratio,monomer concentration,polymerization time and temperature were investigated.Activities of ca.171 kg/Nd·h were obtained under the optimum condition(CL/Nd=1600(molar ratio),[CL]=2.26 mol L^(-1),1 h at 50℃),giving a poly(ε-caprolactone)(PCL)of number-average molecular weight M_n=5.4×10~4 and molecular...

Identification of nitrogen-polyaromatic compounds in asphaltene from co-processing of coal and petroleum residue using chromatography with mass spectrometry

Abstract Asphaltene, from co-processing of coal and petroleum residues is one of the most precious and complex molecular mixtures existing, with tremendous economic relevance. Asphaltene was separated by Soxhlet extraction with methylbenzene and then divided into three parts by distillation. Gas chromatography （GC） and high-performance liquid chromatography （HPLC） were coupled with quadrupole time-of-flight mass spectrometry （Q-TOF MS） to separate and characterize organic nitrogen species in the distillates of asphaltene at molecular level. Molecular mass of compounds was mainly distributed from 150 to 600 ~t. Number of rings plus double bonds （rdb） and synchronous fluorescence spectra indicated that most of the organonitrogen compounds （NPAC） contained heterocyclic aromatic rings, including pyridines, anilines, quinolins, pyrroles, carbazoles and indoles plus various alkyl groups. Constant-wavelength synchronous fluo- rescence spectrometry （CWSFS） indicated NPAC with 2-3 rings were the main structures of organonitrogen compounds and the corresponding structural information was proposed. Some organic nitrogen isomers were separated and identified by atmospheric pressure chemical ionization （APCI） GC-Q-TOF MS and electrospray ionization （ESI） HPLC-Q-TOF MS. The methodology applied here contained chromatographic injection of the diluted sample using conventional columns sets and Data Analysis 4.2 software. Identifying molecular structures provides a foundation to understand all aspects of coal- derived asphaltene, enabling a first-principles approach to optimize resource utilization.

Porous boronate affinity monolith for on-line extraction coupled to high-performance liquid chromatography for sensitive analysis of heterocyclic aromatic amines in food samples

A novel on-line solid-phase microextraction–high-performance liquid chromatography（SPME–HPLC）system was developed for the determination of heterocyclic aromatic amines（HAAs） in food samples. A poly（vinylphenylboronic acid-co-ethylene glycol dimethacrylate） polymer monolith was prepared for on-line efficient extraction and large-volume injection was used to increase the sensitivity of detection.The polymermonolith, based on a ternary porogen, was prepared by in situ polymerization of vinylphenylboronic acid（VPBA） and ethylene glycol dimethacrylate（EGDMA） in a fused-silica capillary column. It showed good permeability, high extraction capacity, and high selectivity. The column-tocolumn reproducibility was satisfactory, and the enrichment factors for HAAs were 3746–7414.Conditions influencing the on-line extraction efficiency, including p H of sample solutions, flow rate of extraction and desorption, and desorption volume, were investigated. The proposed method had low limit of detection（0.10–0.15 ng/L） and good linearity. Trace HAAs in roast beef and lamb samples were determined, and the amounts of 2-amino-3-methylimidazo[4,5-f]quinoline, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, and 2-amino-3,4,7,8-tetramethyl-3H-imidazo[4,5-f]quinoxaline in these samples were 0.235–2.08 ng/g. The recoveries for the five HAAs ranged from74.3% to 119%, and the relative standard deviation（RSDs） were less than 8.2%. The results showed that the proposed on-line method was highly sensitive for monitoring HAAs in different food samples.

Effect of woodchip types on heterocyclic aromatic amine formation and quality characteristics of smoked bacon

The impact of different woodchips(beech,oak,pear,and apple)on the contents of heterocyclic aromatic amines(HAAs)and quality characteristics of smoked bacon was investigated.The results indicated that the contents of total HAAs and non-polar HAAs in beech-and oak-smoked bacon were lower than that in pear-and apple-smoked bacon(P<0.05).There were no HAAs detectable in control(non-smoking)sample.The smoking process promoted the formation of free amino acids(FAA)in the smoked bacon.The total contents of FAA in beech-and oak-smoked bacon were higher than these in the pear-and apple-smoked bacons(P<0.05).The beech-smoked bacon had the highest L^(*)-value(P<0.05),and oak-smoked bacon had the lowest thiobarbituric acid-reactive substance(TBARS)value and carbonyl content(P<0.05).Additionally,woodchip types had no significant influence on a^(*)-value,b^(*)-value,moisture content,aw,T_(20),T_(21) and T_(22)(P>0.05).PCA of the HAA contents and quality characteristics could effectively differentiate that were unsmoked and smoked bacon.Therefore,woodchip types had a great influence on HAA contents and quality of smoked bacon.

THE INTRAMOLECULAR AROMATIC-RING STACKING INTERACTION OF THE TERNARY MIXEDLIGAND COMPLEXES:STUDY OF Pd^(2+)-HETEROCYCLIC RING BASE-NUCLEOTIDE SYSTEM BY POTENTIOMETRIC pH TITRATION

One of the typical phenomena of intramolecular ligand-ligand interaction in complexes is the aromatic-ring stacking which depends on the stacking of those non-coordinating aromatic rings. Since 1974 H. Sigel reported that the stacking interaction was observed between pyridine ring of bpy（bpy=2, 2′-bipyridyl） and purine ring of ATP4-(ATP4-=adenosine 5′-triphosphate) among the mixed-ligand Cu（bpy） （ATP）2- complexes. The study on this field has been extended to a large amount of ligands such as nucleotides, xanthosines,

Critical steps in the production of oil from oilseed to reduce heterocyclic aromatic amines

Contamination by the heterocyclic aromatic amines(HAAs)norharman and harman is one of the risks in vegetable oil production,so oil producers strive to decrease their content in the end products.In this study,the effects of production conditions—specifically,two pretreatment methods(roasting and microwaving),four extraction methods(two pressing and two solvent extraction)and adsorption refining(four absorbents)—of five oils(flaxseed,peanut,rapeseed,sesame,and sunflower seed)were evaluated.The results showed that microwaving as a pretreatment produced significantly fewer HAAs than roasting(P<0.05).After two pretreatments,the HAA content of oils was ranked from high to low as follows:sunflower oil,sesame oil,flaxseed oil,rapeseed oil,and peanut oil.Solvent-extracted oils(9.16–316.73μg/kg)had fewer HAAs than pressed oils(26.61–633.93μg/kg).Using adsorbents reduced HAAs in oils from the initial 21.77–484.22 to 0.31–41.58μg/kg,and the removal rate reached 99.28%.This study provides critical HAA reduction strategies for application in the oil production process to obtain safe final products.

伊立替康药物中间体7-乙基喜树碱合成的课程思政设计

抗癌药物伊立替康中间体7-乙基喜树碱的合成是杂环芳烃的烷基化反应。本案例通过将实验过程与药物合成和“健康中国”相关联,对实验进行了创新性的思政融入设计。师生全员在案例的导入、研讨、实施、反思与考核的全过程进行全方位的课程思政教育,解决了实验课只注重实验内容而忽略思政教育的问题,实现了“三全育人”。在此过程中不仅激发了学生的学习兴趣,有效地进行了科学思维和创新思维的训练,培养了学生的探索精神和创新意识,而且强化了学生提高原子利用率的绿色化学意识、环保意识和可持续发展意识,提升了学生为健康中国贡献力量的责任感和使命感,坚定了学生运用所学专业知识服务国家的决心和信心。

基于福井函数方法的芳杂环化合物亲电取代反应位点预测及图形可视化教学应用

基于福井函数方法,利用Gaussian和Multiwfn软件预测了常见芳杂环化合物及取代芳杂环化合物的亲电取代反应位点,使之以可视化图像形式展现并应用于基础有机化学的教学实践。

芳杂环亚胺类化合物的研究进展

芳杂环亚胺类化合物因其特有的C=N键,具有很强的生物活性,在医药、材料、农业和染料等领域应用十分广泛。芳杂环亚胺类化合物也是一类重要有机中间体,可以发生还原、加成、环氧化等众多有机反应,更是杂环合成中的重要前体之一。本文围绕着芳杂环亚胺类化合物的种类、应用和国内外研究进展进行综述,为日后合成芳杂环亚胺类化合物提供一定参考。

高温煤焦油中稠环芳烃和氮杂环芳香族化合物的分离富集

煤焦油是高附加值稠环芳烃的主要来源,甚至是某些芳香族化合物的唯一来源。先用纯石油醚,再用乙酸乙酯体积分数为5%和30%的石油醚/乙酸乙酯混合溶剂依次作为洗脱剂,采用柱层析法对高温煤焦油的石油醚萃取物洗脱,得到洗脱液1-3(E_(1)-E_(3))。在E_(1-6)和E_(1-10)中富集到5种四环稠环芳烃,其中荧蒽在E_(1-10)中相对含量达71.02%。此外,在E_(2-2)中富集到6种酚类和9种氮杂环芳香族化合物,在E_(3-2)中富集到7种1~4环的氮杂环芳香族化合物。

N-异海松酰基-N′-芳杂环基硫脲类衍生物的合成及生物活性

为得到潜在的新型抑菌剂和抗肿瘤药物,笔者以异海松酸为原料,先与草酰氯反应制备得到异海松酰氯,后与硫氰化钾反应生成异海松酰基异硫氰酸酯,在此基础上与不同杂环取代胺反应,设计并合成了10个新型N-异海松酰基-N′-芳杂环基硫脲类衍生物4a~4j,采用傅里叶红外光谱(FT-IR)、氢核磁共振(1H NMR)、碳核磁共振(13C NMR)和质谱(MS)等手段确定了目标化合物的结构,研究了N-异海松酰基-N′-芳杂环基硫脲类衍生物的抑菌及抗肿瘤活性。研究结果表明,大部分N-异海松酰基-N′-芳杂环基硫脲类衍生物对金黄色葡萄球菌都具有良好的抑菌活性,其中化合物4b、4c、4d、4e和4f对金黄色葡萄球菌的最低抑菌质量浓度达到0.98μg/mL,优于对照物青霉素钠,其中化合物4h的最低抑菌质量浓度也达到15.60μg/mL;化合物4i和4j的最低抑菌质量浓度为31.30μg/mL,大部分衍生物对樟子松枯梢病菌和无壳异担子菌无明显的抑菌活性。在浓度为100μmol/L时,部分N-异海松酰基-N′-芳杂环基硫脲类衍生物具有较好的抗肿瘤活性,化合物4f和4g对肝癌细胞的体外抑制率分别为68.59%和82.30%,化合物4g对宫颈癌细胞、前列腺癌细胞和乳腺癌细胞的体外抑制率分别为80.74%、71.21%和62.14%。

不同烟熏时间鸡腿肉香气化合物与危害物及相关前体物研究

为探究不同熏制时间下熏鸡风味成分和危害物的变化及其与前体物的关系,利用色谱质谱等技术对香气化合物、杂环胺(HAs)、晚期糖基化终末产物(AGEs)、多环芳烃(PAHs)、还原糖、游离氨基酸与脂肪酸等进行定性定量分析。结果表明,在熏鸡腿中共鉴定出67种香气化合物,气味活性值(OAVs)>1的香气化合物有24种,以愈创木酚贡献率最大。随着熏制时间增加,酚类化合物、HAs、AGEs和4种多环芳烃(PAH4)含量显著升高(P<0.05),而水分、肌酐和葡萄糖则逐渐减少。9H-吡啶并[3,4-b]吲哚(Norharman)、羧甲基赖氨酸(CML)、羧乙基赖氨酸(CEL)和?(Chr)是熏鸡中主要潜在危害物,熏制12 h后的含量分别为37.38 ng·g^(-1)、123.94μg·g^(-1)、180.13μg·g^(-1)和41.10μg·kg^(-1)。最佳熏制时间为6 h,长时间熏制不利于熏鸡香气化合物的保持且伴生大量危害物。相关性分析表明,壬醛、1-辛烯-3-醇、2,5-二甲基吡嗪等关键香气化合物含量与还原糖、部分游离氨基酸和不饱和脂肪酸含量显著负相关;Norharman、CEL和PAH4等含量与多种游离氨基酸、水分等含量显著或极显著负相关;苯丙氨酸、甲硫氨酸、酪氨酸和色氨酸等含量同时与香气化合物和危害物含量显著(P<0.05)或极显著正/负相关(P<0.01)。本研究揭示了熏鸡熏制过程中香气化合物与危害物协同伴生关系,可为熏鸡风味保持和危害物消减提供数据基础。

低共熔溶剂双水相萃取-UPLC法检测吸烟者尿液中杂环胺类化合物

为评估香烟烟气中杂环胺的暴露水平,建立了一种基于低共熔溶剂/无机盐双水相萃取-UPLC法测定吸烟者尿液中5种杂环胺(IQ,IQ[4,5-b],Harman,Norharman和Phe-P-1)的方法.制备了7种以氯化胆碱(ChCl)为氢键受体的低共熔溶剂,并对其进行了表征;系统考察了影响萃取效率的主要参数,并将该方法与其它方法进行了对比研究.结果表明,在最佳提取条件下,杂环胺(HAAs)的回收率为81.9%~106.2%,日内和日间精密度分别低于2.9%和3.2%,检出限和定量限分别为0.020~0.097 ng/g和0.19~0.39 ng/g.该方法具有操作简单、环境友好及单样品成本低等特点,为尿液中杂环胺的检测提供了一种新方法,在生物样品检测领域具有良好的开发与应用价值.

食品中杂环胺在机体中的代谢机制和减控措施的研究进展

杂环胺作为一类热诱导形成的有害物,广泛存在于富含蛋白质的高温加工食品中。经体内代谢活化后具有较强的致癌和致突变性,可对机体造成严重危害。该文详细综述了杂环胺的分类、在不同食品中的含量及检测方法、代谢机制、毒性作用及其减控措施,以充分揭示食品有害物杂环胺发挥毒性作用的机理,以期为其毒性控制和探索新型减控措施提供参考。

活性羰基化合物及其对食品加工过程中化学危害物形成的影响

活性羰基化合物(reactive carbonyl species,RCSs)是一类活泼的醛酮类物质。RCSs在体内通过脂质氧化和糖酵解等反应形成,也可在食品加工过程中通过脂质氧化和美拉德反应形成。RCSs在体内通常维持一个低浓度水平,当过量存在时会引起机体系列病变发生。人体摄入RCSs主要源于加工食品,与此同时,食品加工过程中的RCSs还会诱导其他加工危害物的形成,因此控制食品中RCSs的形成对于营养健康至关重要。本文对RCSs的形成、生物学活性,及其对食品加工中杂环胺、晚期糖基化终末产物、丙烯酰胺以及多环芳烃等加工危害物形成的影响进行综述,以期为食品加工中RCSs及其相关食品加工安全控制提供参考。

改良QuEChERS方法结合超高效液相色谱测定火腿肠中杂环胺类化合物

以火腿肠为研究对象,建立以磁性氧化石墨烯为基质净化材料的改良QuEChERS方法,结合超高效液相色谱(UPLC)技术快速测定火腿肠中4种杂环胺(IQ、Harman、Norharman和Phe-P-1)含量,利用方法学考查该方法的分析性能,并将其用于实际样品的检测。结果表明,与传统净化材料相比,所合成的磁性氧化石墨烯材料具有更高或相当的杂环胺回收效果和基质净化能力,可用作改良QuEChERS方法的净化材料。改良QuEChERS方法的适宜条件为:提取溶剂为碱化乙腈(含体积分数1%的氨水)、用水量1 mL、涡旋萃取时间5 min、萃取盐为无水Na_(2)SO_(4)/NaCl(用量0.50 g/0.13 g)、离心时间3 min,磁性氧化石墨烯用量7.5 mg、净化时间1 min。该条件下,4种杂环胺的R2均大于0.9995,在低、中、高浓度3个加标水平下杂环胺的回收率分别为99.9%~104.3%、101.2%~106.7%和85.7%~101.2%,检出限和定量限分别为0.71~1.52 ng/g和1.00~2.53 ng/g,日内及日间精密度分别低于4.4%和4.9%,精确度和精密度均良好。11种市售火腿肠均未检出4种HAAs,但检测到多种未知物质,且其含量均高于本文方法的定量限。与其他常用前处理技术相比,本文方法具有快速、简便、单样品成本低、有机溶剂用量少等特点,可用于火腿肠中杂环胺的检测。