Minimal clean-up and rapid determination of polycyclic aromatic hydrocarbons in instant coffee

The essential aim of this work is the development of a simple, fast, quantitative and economic method for polycyclic aromatic hydrocarbons (PAHs) potentially generated by roasting coffee beans, which is the most important process in the coffee industry for the development of the characteristic flavour of the bean mix. The PAHs were chosen because they differed in the number of aromatic rings, had different polarity, have low residual limits, are commonly widespread in the environment and are generated by roasting. The key issue is whether or not the most polar PAHs, those with lower molecular weight or less rings, appear in the water extracts of ground roasted coffee beans, taking into account that those PAHs with lower molecular weight are those with higher volatality. The proposed analytical method is also broadly applicable to other roasted foods or their aqueous extracts. The method was evaluated by constructing calibration curves, measurement of recovery and precision, and the limits of detection. The method involves extraction with hexane, clean-up with a silica cartridge, concentration to dryness and injection of the acetonitrile solution of the residue for HPLC analysis with fluorescence detection. The method allowed to confirm or not the presence of the selected PAHs in instant coffees.     

Occurrence of polycyclic aromatic hydrocarbons in smoked cheese

The presence of polycyclic aromatic hydrocarbons (PAH) in smoked cheeses of different origin was studied. The samples were subjected to an initial extraction of fat and an alkaline treatment, extracted with cyclohexane, cleaned up by means of solid-phase extraction tubes, and analyzed by gas chromatography/mass spectrometry (GC/MS) operating in selective ion-monitoring mode (SIM). The results revealed the presence of numerous polycyclic aromatic hydrocarbons in the exterior zone of the samples, some of them with methyl groups. In all cases, the concentrations of compounds of low molecular weight were much higher than those of high molecular weight. Polycyclic aromatic hydrocarbons with varying degrees of carcinogenicity were identified, including benzo(a)pyrene in concentrations, which, although they did not exceed the limit established for this compound in the rind of ripened cheeses, do exceed the limit of 0.03 microg/kg fixed for other foods smoked with smoke flavorings. Significant differences in the number and concentration of PAH in smoked cheese also were observed from rind to interior, the rind being the most contaminated zone.     

食品中多环芳烃及卤代多环芳烃的研究进展

综述了多环芳烃及卤代多环芳烃的性质、毒性及国内外食品中的污染情况和研究现状,并对目前的分析测定方法进行了介绍,希望为我国开展食品领域内多环芳烃和卤代多环芳烃的研究提供参考。     

Factors affecting elimination of polycyclic aromatic hydrocarbons from smoked meat foods and liquid smoke flavorings

This review deals with effects of environmental and physicochemical factors affecting polyaromatic hydrocarbon (PAH) elimination from smoked meat products and liquid smoke flavoring (LSF). In the introductory part, some essential information are aimed at principles of food smoking and PAH formation during smoke generation as a result of incomplete wood combustion. Also, an application of alternative technology for food aromatization using LSF is briefly mentioned. Similarly, latest European legislation, biological effects, and analytical aspects of PAHs are mentioned concisely. The main part is devoted to physicochemical factors affecting the PAH content in smoked meat products, such as light, additional cooking, and packaging, which are able to decrease considerably PAH content in some meat products. The most important effect on PAH concentration decrease in LSF has low-density polyethylene (LDPE) package due to sorption processes on a surface of the plastic with subsequent diffusion into the plastic bulk. A less effective material is polyethylene terephthalate (PET), when only a surface adsorption process comes into account. Moreover, this process is affected also by other compounds presented in liquid media able to compete for the adsorption center on the PET surface.     

Reduction strategies for polycyclic aromatic hydrocarbons in processed foods

Polycyclic aromatic hydrocarbons (PAHs) are a large group of carcinogenic compounds. PAHs are ubiquitous in the environment and food, thus human beings may be exposed to PAHs through ingestion (water and food), inhalation (air and smoking), and skin contact in daily life. Dietary intake is the major source of exposure to PAHs in humans. Significant and harmful levels of PAHs can be generated during food processing and cooking. Although the formation of PAHs during processing is almost unavoidable, the levels can be diminished with reduction strategies. This review aims to provide comprehensive insights into the mechanisms underlying the formation of PAHs and factors influencing their formation in processed foods. The strategy for the reduction of PAHs including change in ingredients (i.e., reducing fat content), pretreatment conditions (i.e., reducing the pH), processing methods and parameters (i.e., reducing processing temperature and time), and packaging and storage conditions, are discussed. Potential novel strategies for PAH reduction are also identified and the feasibility is evaluated.     

Optimisation and validation of an HPLC method for determination of polycyclic aromatic hydrocarbons (PAHs) in mussels

A method for determination of 11 polycyclic aromatic hydrocarbons (PAHs) in mussels (Mytilus galloprovincialis), using HPLC coupled to a fluorescence detector, has been optimised and validated, according to European Community rules. Sample preparation involves alkaline digestion of mussel tissue, liquid–liquid extraction of organic compounds and solid phase clean-up. Accuracy and precision of the method were determined by a validation study, carried out to demonstrate that the method is useful for both screening purposes and confirmation. Commission Regulation (EC) No. 2007/333/EC stated the performance criteria for the analysis of the only benzo[a]pyrene (BaP) in food products of animal origin, since BaP is the most studied PAH. We extended the BaP analysis performance criteria to other 10 toxic PAHs (listed in Commission Recommendation (EC) No. 2005/108/EC) and the validation study was performed also in agreement with Commission Decision (EC) No. 2002/657/EC. The method was applied to investigate 27 mussel samples from actively producing shellfish plants located in Campania (Italy) and variable levels of PAHs were detected ranging from <0.2 to 16 μg/kg wet weight.     

食品中多环芳烃的提取、纯化、以及检测方法的研究进展

对食品中多环芳烃(PAHs)的提取、纯化机理和检测方法进行了概述,侧重介绍了样品提取、纯化和分离过程中影响PAHs回收率的各种因素。     

HPLC determination of polycyclic aromatic hydrocarbons in olive oils

 In this paper, HPLC with spectrofluorimetric detection was applied to the determination of polycyclic aromatic hydrocarbons (PAHs) in olive oils. These compounds may sometimes contaminate vegetable oils because of their specific lipophilic characteristics, which are a significant problem for their extraction and purification from lipid matrices. Some improvements to previously published methods are introduced and satisfactory results for repeatability and recovery were obtained. Data on 51 authentic olive oil samples are reported and it was found that there is usually a limited presence of PAHs in extra virgin olive oils; furthermore, the analysis of some blends of refined and virgin oils shows that the distributions of light and heavy PAHs are different with the content of the former being lower in refined samples. As an example of this fact, two samples of lampante oil were followed throughout the refining step. Received: 23 September 1996 / Revised version: 17 December 1996     

食品中痕量多环芳烃检测技术的研究进展

多环芳烃(polycyclic aromatic hydrocarbons, PAHs)是造成食品污染的痕量危害物质, 精确和快速的检测食品中的痕量多环芳烃, 是食品安全重要的技术保障。本文概括了易受PAHs污染的食品类型, 综述了食品中PAHs的主要检测技术及其的研究进展。检测技术主要包括色谱检测、光谱检测和免疫学检测方法, 其中色谱检测高效液相色谱(high performance liquid chromatography, HPLC)和气相色谱-质谱(gas chromatography-mass spectrometer, GC-MS)是食品中PAHs的主流检测方法, 荧光光谱法、表面增强拉曼光谱法光谱检测和免疫学检测在食品PAHs检测中也已常见, 免疫学检测法基于其快速和现场性特点, 显示出极强的应用前景潜力。并对未来的研究趋势进行展望。     

Evaluation of polycyclic aromatic hydrocarbons content in different stages of soybean oils processing

A study was conducted in order to determine the levels of 13 polycyclic aromatic hydrocarbons (PAHs) in crude soybean oils produced in Brazil and to evaluate the influence of the refining process in their reduction. Analysis of intermediary products (neutralized, bleached and deodorized oils) showed that all compounds were reduced through refining (up to 88%). Neutralization and deodorization steps contributed effectively to the PAHs decrease. The mean total PAHs content in crude and deodorized oil samples ranged, respectively, from 10 to 316 and 3 to 69μg/kg. Since vegetable oils have been shown to be the major sources of PAHs in the diet, a monitoring program should be developed by the refining industries and the use of activated carbon during oil processing is highly recommended.     

油籽炒籽条件对油脂中多环芳烃含量影响的研究

以花生仁和芝麻籽为原料,研究了炒籽温度和炒籽时间对其油脂中16种多环芳烃含量的影响。结果表明,随着炒籽温度的提高及炒籽时间的延长,花生油和芝麻油中Bap、PAH4、PAH16的含量都呈明显上升趋势。对照GB2716及欧盟No 835/2011中对Bap、PAH4的限量规定,花生仁的合理炒籽温度为不超过160℃、炒籽时间不超过20 min,芝麻的合理炒籽温度为不超过180℃、炒籽时间不超过20 min。在优化的炒籽条件下,花生油中Bap、PAH4、PAH16含量(μg/kg)分别从原料中的0.31、4.60、16.69增加至1.07、11.98、48.86,芝麻油中Bap、PAH4、PAH16含量分别从原料中的0.63、5.23和21.84增加至0.93、8.28和47.95。     

四种多环芳烃低剂量联合暴露对大鼠毒性作用的初步研究

目的 初步研究4种多环芳烃(苯并[a]芘、苯并[a]蒽、艹屈和苯并[b]荧蒽)低剂量联合暴露的毒性作用。方法 购入50只8周龄SD雄性大鼠,随机分为5组,每组10只,分别按0、10、50、250、1000 μg/kg·BW剂量连续灌胃染毒,基于人体4种多环芳烃的实际暴露量,灌胃剂量的比例设定为苯并[a]芘∶苯并[a]蒽∶艹屈∶苯并[b]荧蒽=0.99∶2.92∶2.68∶1.68。大鼠于染毒30 d后处死,取血清、脏器等生物样本,计算脏器系数,进行大鼠肝脏病理切片观察病理学改变,并检测肝功能相关指标、氧化应激相关指标及脂代谢相关指标。结果 相较于对照组,染毒组大鼠肝脏结构有明显异常,肝窦扩大,肝细胞出现气球样变;1 000 μg/kg·BW组肝脏脏器比显著升高。染毒30 d后1 000 μg/kg·BW组大鼠血清谷草转氨酶均显著上升(P<0.05);染毒组大鼠血清谷胱甘肽过氧化物酶在30 d时显著升高(P<0.05);染毒30 d后,1 000 μg/kg·BW组大鼠血清高密度脂蛋白胆固醇显著下降并且肝脏胆固醇显著上升(P<0.05),250 μg/kg·BW组大鼠血清甘油三酯显著上升(P<0.05),50 μg/kg·BW及以上染毒剂量的染毒组肝脏中TG显著上升(P<0.05)。结论 PAH4低剂量联合暴露对SD雄性大鼠产生了一定程度的肝损伤、氧化应激及脂代谢紊乱等不良影响。     

食品中多环芳烃的研究进展

简述了近年来关于食品中多环芳烃的形成机理、分析方法及控制措施的研究进展,以期为解决食品中多环芳烃的污染问题提供依据。     

Milk and urine excretion of polycyclic aromatic hydrocarbons and their hydroxylated metabolites after a single oral administration in ruminants

The aim of this study was to establish the transfer of phenanthrene, pyrene, and benzo[a]pyrene and their major hydroxylated metabolites to milk and to urine after a single oral administration (100 mg per animal of each compound) in 4 lactating goats. Detection and identification of the analytes (native compounds, 1-OH pyrene, 3-OH phenanthrene, 3-OH benzo[a]pyrene) were achieved using gas chromatography-mass spectrometry. Benzo[a]pyrene, phenanthrene, and pyrene were rapidly detected in the plasma stream, whereas 1-OH pyrene and 3-OH phenanthrene appeared later in plasma. These data suggest that pyrene and phenanthrene are progressively metabolized within the organism. Recovery rates of pyrene and phenanthrene in milk over a 24-h period appeared to be very low (0.014 and 0.006%, respectively), whereas the transfer rates of their corresponding metabolites were significantly higher: 0.44% for 1-OH pyrene and 0.073% for 3-OH phenanthrene. Recovery rates in urine were found to be higher (1 to 10 times) than recovery rates in milk. The 1-OH pyrene was found to be the main metabolite in urine as well as in milk. Thus, as has been established for humans, 1-OH pyrene could be considered as a marker of ruminant exposure to polycyclic aromatic hydrocarbons. Because 1-OH pyrene and 3-OH phenanthrene were measured in milk (unlike their corresponding native molecules), metabolites of polycyclic aromatic hydrocarbons should be taken into consideration when evaluating the safety of milk. Benzo[a]pyrene and 3-OH benzo[a]pyrene were (less than 0.005%) transferred to milk and urine in very slight amounts. This very limited transfer rate of both compounds suggests a low risk of exposure by humans to benzo[a]pyrene or its major metabolite from milk or milk products.     

8种多环芳烃联合暴露致大鼠肝脏毒性及BMDL推导

目的 探究8种多环芳烃（PAH8）联合暴露的大鼠肝脏毒性,利用基准剂量法（BMD）获得PAH8致肝脏毒性的基准剂量95%置信区间下限值（BMDL）。方法 雄性SD大鼠随机分为5组,每组10只,分别按照0、10、50、250和1 000μg/kg·BW剂量的PAH8连续染毒30 d后处死大鼠,计算脏器系数,进行肝脏病理学检测和油红O染色,检测血清谷丙转氨酶、谷草转氨酶、丙二醛、谷胱甘肽过氧化物酶（GSH-Px）、甘油三酯（TG）、总胆固醇（TC）的水平及肝脏TG、TC含量。选择具有统计学意义、毒理学意义和剂量效应趋势的肝脏毒性数据,利用BMDS 3.2软件进行BMD分析,选择最佳拟合模型得到BMDL值。结果 1 000μg/kg·BW剂量组大鼠肝脏系数较对照组显著升高（P<0.05）。PAH8染毒后部分大鼠肝脏出现细胞水肿、炎性浸润、脂肪变性等病理改变。10～250μg/kg·BW剂量组血清GSH-Px较对照组显著升高（P<0.01）,但1 000μg/kg·BW剂量组GSH-Px显著降低（P<0.001）。肝脏中TC含量呈现剂量效应趋势,1 000μg/kg·BW剂量...     

Residue pattern of polycyclic aromatic hydrocarbons during green tea manufacturing and their transfer rates during tea brewing

ABSTRACT

Residues of polycyclic aromatic hydrocarbons (PAHs) in green tea and tea infusion were determined using gas chromatography-tandem mass spectrometry to study their dissipation pattern during green tea processing and infusion. Concentration and evaporation of PAHs during tea processing were the key factors affecting PAH residue content in product intermediates and in green tea. PAH residues in tea leaves increased by 2.4–3.1 times during the manufacture of green tea using the electric heating model. After correction to dry weight, PAH residue concentrations decreased by 33.5–48.4% during green tea processing because of PAH evaporation. Moreover, spreading and drying reduced PAH concentrations. The transfer rates of PAH residues from green tea to infusion varied from 4.6% to 7.2%, and PAH leaching was higher in the first infusion than in the second infusion. These results are useful for assessing exposure to PAHs from green tea and in formulating controls for the maximum residue level of PAHs in green tea.     

Sources of contamination by polycyclic aromatic hydrocarbons in Spanish virgin olive oils

The presence of polycyclic aromatic hydrocarbons (PAHs) in virgin olive oils results from contamination on olive skins and the oil itself during processing. Determination of nine PAHs was carried out by isolation of the hydrocarbon fraction and subsequent clean-up by solid phase extraction, followed by RP-HPLC analysis using a programmable fluorescence detector. Contamination of olive skins depends directly on environmental pollution levels and inversely on fruit size. In the oil mill, PAHs levels were increased by contamination from combustion fumes during the extraction process. Other procedures, such as washing or talc addition during extraction, did not affect PAHs levels. High concentrations of PAHs were only found as a consequence of accidental exposure to contamination, such as direct contact of olives with diesel exhaust and oil extraction in a polluted environment.     

Sources of contamination by polycyclic aromatic hydrocarbons in Spanish virgin olive oils

The presence of polycyclic aromatic hydrocarbons (PAHs) in virgin olive oils results from contamination on olive skins and the oil itself during processing. Determination of nine PAHs was carried out by isolation of the hydrocarbon fraction and subsequent clean-up by solid phase extraction, followed by RP-HPLC analysis using a programmable fluorescence detector. Contamination of olive skins depends directly on environmental pollution levels and inversely on fruit size. In the oil mill, PAHs levels were increased by contamination from combustion fumes during the extraction process. Other procedures, such as washing or talc addition during extraction, did not affect PAHs levels. High concentrations of PAHs were only found as a consequence of accidental exposure to contamination, such as direct contact of olives with diesel exhaust and oil extraction in a polluted environment.     

Rapid determination of polycyclic aromatic hydrocarbons in natural tocopherols by high-performance liquid chromatography with fluorescence detection

A simple and rapid method has been developed and validated for the determination of seventeen polycyclic aromatic hydrocarbons (PAHs) in natural tocopherol products. Samples were dissolved in n-hexane, cleaned by an alumina column, and separated and determined by reversed-phase high-performance liquid chromatography (HPLC) with fluorescence detection. The recoveries were greater than 77.9%, except for the lowest molecular weight PAHs (Na, 1-Me, 2-Me, AC, F) which were between 15.9% and 75.8%. The limits of quantification were less than 0.38 ng/g for the heavy PAHs and less than 1.50 ng/g for the light PAHs. Good repeatabilities were achieved with RSD less than 10.7% for all the objective compounds. This method has been applied to evaluating PAHs contents in various natural tocopherol products and controlling natural tocopherol product quality.     

Analysis of polycyclic aromatic hydrocarbons in fish: Optimisation and validation of microwave-assisted extraction

An accurate and sensitive method for determination of 18 polycyclic aromatic hydrocarbons (PAHs) (16 PAHs considered by USEPA as priority pollutants, dibenzo[a,l]pyrene and benzo[j]fluoranthene) in fish samples was validated. Analysis was performed by microwave-assisted extraction and liquid chromatography with photodiode array and fluorescence detection. Response surface methodology was used to find the optimal extraction parameters. Validation of the overall methodology was performed by spiking assays at four levels and using SRM 2977. Quantification limits ranging from 0.15–27.16 ng/g wet weight were obtained. The established method was applied in edible tissues of three commonly consumed and commercially valuable fish species (sardine, chub mackerel and horse mackerel) originated from Atlantic Ocean. Variable levels of naphthalene (1.03–2.95 ng/g wet weight), fluorene (0.34–1.09 ng/g wet weight) and phenanthrene (0.34–3.54 ng/g wet weight) were detected in the analysed samples. None of the samples contained detectable amounts of benzo[a]pyrene, the marker used for evaluating the occurrence and carcinogenic effects of PAHs in food.