Accelerated solvent extraction method for the quantification of polycyclic aromatic hydrocarbons in cocoa beans by gas chromatography-mass spectrometry

New research development on trans fatty acids in food: Biological effects, analytical methods, formation mechanism, and mitigating measures

The trans fatty acids (TFAs) in food are mainly generated from the ruminant animals (meat and milk) and processed oil or oil products. Excessive intake of TFAs (>1% of total energy intake) caused more than 500,000 deaths from coronary heart disease and increased heart disease risk by 21% and mortality by 28% around the world annually, which will be eliminated in industrially-produced trans fat from the global food supply by 2023. Herein, we aim to provide a comprehensive overview of the biological effects, analytical methods, formation and mitigation measures of TFAs in food. Especially, the research progress on the rapid, easy-to-use, and newly validated analytical methods, new formation mechanism, kinetics, possible mitigation mechanism, and new or improved mitigation measures are highlighted. We also offer perspectives on the challenges, opportunities, and new directions for future development, which will contribute to the advances in TFAs research.

Polycyclic aromatic hydrocarbons (PAHs) in the upstream rivers of Taihu Lake Basin, China: spatial distribution, sources and environmental risk

The polycyclic aromatic hydrocarbon (PAH) pollution in Taihu Lake Basin has caused widespread concern. However, the spatial temporal distribution of PAHs in the upstream rivers of Taihu Lake Basin remains largely unknown. Thus, this study aims to investigate the level, spatial distribution, sources, and environment risk caused by PAHs in upstream rivers of Taihu Lake Basin. The concentrations of total 16 PAHs (∑16PAHs) ranged from 188.64 to 1060.39 ng/g, with an average of 472.62 ng/g. High-molecular-weight (HMW) PAHs were the predominant compounds in most sample sites. The results of source analysis demonstrated that the PAH pollution was mainly sourced from mixture of combustion and direct petroleum spillage. The ecological risk assessment showed that moderate ecological risk caused by the PAH contaminants might occur in most sample sites. The incremental lifetime cancer risks (ILCRs) ranged from 2.07 ×10-4 - 2.66 × 10-3 for children and 9.66 ×10-5 - 1.24 × 10-3 for adult, indicating moderate cancer risk of PAH-contaminated sediments.

Determination of contaminants of emerging concern and their transformation products in treated-wastewater irrigated soil and corn

In many parts of the world, clean water has become increasingly scarce. Irrigation of agricultural land with treated wastewater is commonly used in response to water shortages but there is concern about the environmental fate and transport of contaminants present in the irrigation wastewater. This study aimed to examine the presence of wastewater sourced contaminants in soil and field grown corn (Zea mays) crops spray irrigated with treated wastewater. Soil, corn grain, leaves, and roots were sampled and tested from a long-term wastewater irrigation site as well as a non-irrigated control site in close geographic proximity. Samples were analyzed using comprehensive two-dimensional gas chromatography coupled to time of flight mass spectrometry (GC × GC-TOFMS) and both targeted and non-targeted analyses were conducted to determine chemical differences between the wastewater irrigated and control samples. Target compounds detected and quantified in the samples include herbicides, phthalates, and polycyclic aromatic hydrocarbons. Non-targeted analysis showed chemical differences between each the wastewater irrigated and control samples. Furthermore, new chloro-dimethyl-benzotriazole compounds, which are suspected to be transformation products created by the chlorine disinfection process of the wastewater treatment plant, were tentatively identified in the wastewater effluent. Twenty of these new benzotriazoles were detected and semi-quantified in the wastewater irrigated soil samples at a maximum concentration of 472 ng/g. Eight of the most abundant benzotriazoles were also detected in the corn roots at concentrations up to 56 ng/g.

Polycyclic Aromatic Hydrocarbons in Foods: Biological Effects, Legislation, Occurrence, Analytical Methods, and Strategies to Reduce Their Formation

Polycyclic aromatic hydrocarbons (PAHs) are chemical compounds comprised of carbon and hydrogen molecules in a cyclic arrangement. PAHs are associated with risks to human health, especially carcinogenesis. One form of exposure to these compounds is through ingestion of contaminated food, which can occur during preparation and processing involving high temperatures (e.g., grilling, smoking, toasting, roasting, and frying) as well as through PAHs present in the soil, air, and water (i.e., environmental pollution). Differently from changes caused by microbiological characteristics and lipid oxidation, consumers cannot sensorially perceive PAH contamination in food products, thereby hindering their ability to reject these foods. Herein, the occurrence and biological effects of PAHs were comprehensively explored, as well as analytical methods to monitor their levels, legislations, and strategies to reduce their generation in food products. This review updates the current knowledge and addresses recent regulation changes concerning the widespread PAHs contamination in several types of food, often surpassing the concentration limits deemed acceptable by current legislations. Therefore, effective measures involving different food processing strategies are needed to prevent and reduce PAHs contamination, thereby decreasing human exposure and detrimental health effects. Furthermore, gaps in literature have been addressed to provide a basis for future studies.

Cocoa beans of different origins and varieties and their derived products contamination with polycyclic aromatic hydrocarbons

Levels of polycyclic aromatic hydrocarbons (PAHs) in cocoa beans of several varieties originating from different countries and their derived products from one technological line were examined. PAHs analysis was performed using HPLC-FLD/DAD and confirmed by GC-MS. Significant differences in total 19 PAHs contents between raw cocoa beans of different varieties and origins were observed. The highest sums of 19 PAHs were determined in roasted cocoa beans, cocoa mass and cocoa butter (16.69-74.15 μg kg^-1 of fat). The roasting temperature of 160 °C led to PAHs formation, though not the heavy ones. Lowering temperature to 140 °C while extending the time minimized the total contamination but to a small extent. In all samples relatively low levels of total contamination were noted, with light PAHs being predominant and the sum of 4 heavy and marker PAHs much lower than the maximum legal limit. Therefore, analysed products, especially chocolate, do not threaten consumers' health.

Quantification of PAH4 in roasted cocoa beans using QuEChERS and dispersive liquid-liquid micro-extraction (DLLME) coupled with HPLC-FLD

Roasting is an important process in cocoa production which may lead to formation of non-desirable compounds such as polycyclic aromatic hydrocarbons (PAHs). Therefore, PAH4 (sum of four different polycyclic aromatic hydrocarbons; benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) in roasted cocoa beans was determined using a modified method (combination of QuEChERS and DLLME), and quantified by HPLC-FLD. The modified method was validated and met the performance criteria required by the EU Regulation (No. 836/2011). Results show a significant (p < 0.05) increase of PAH4 (0.19-7.73 ng/g) with an increase in temperatures (110-190 °C) and duration (10-50 min). The PAHs content in whole cocoa bean roasting was detected even at the lowest temperature (110 °C) compared to nib roasting detected at 150 °C which indicates that PAHs was transferred from dried shells to roasted cocoa beans during the roasting process. The data obtained may help to control and minimize PAH4 formation during cocoa processing.

Development of a screening analytical method for the determination of non-dioxin-like polychlorinated biphenyls in chicken eggs by gaschromatography and electron capture detection

A sensitive and reproducible screening analytical method is here proposed for the determination of six non dioxin-like polychlorinated biphenyls (NDL-PCBs, congener 28, 52, 101, 138, 153, 180) in chicken eggs based on accelerated solvent extraction (ASE) procedure for the fat extraction and determination, a solid phase extraction (SPE) sample clean-up process, and a gas chromatography - electron capture detection (GC-ECD) analysis. The optimized chromatographic separation, in less than 25 min, returned good responses for the six NDL-PCBs in the range of 2.5-60.0 µg L^-1, with correlation coefficients always higher than 0.9995. Instrumental limits of detection were between 0.08-0.35 µg L^-1, corresponding to 0.05 and 0.23 ng g^-1 fat in the matrix, while method detection limits, calculated on spiked egg samples, ranged from 1.6 to 3.5 ng g^-1 fat. The method has been extensively validated in terms of selectivity, sensitivity, recovery, precision, ruggedness and measurement uncertainty, following the European Directives.

Occurrence, composition profiles and risk assessment of polycyclic aromatic hydrocarbons in municipal sewage sludge in China

A nationwide survey, including 75 sludge samples and 18 wastewater samples taken from different wastewater treatment plants (WWTPs) from 23 cities, was carried out to investigate the occurrence and composition profiles of polycyclic aromatic hydrocarbons (PAHs) in China. In total, the concentrations of ∑₁₆PAHs in sludge ranged from 565 to 280,000 ng/g (mean: 9340 ng/g) which was at a moderate level in the world. The composition profiles of PAHs were characterized by 3- and 4-ring PAHs in textile dyeing sludge and 4- and 5-ring PAHs in domestic sludge. Significant variations in regional distribution of PAHs were observed. Both the principal components analysis and diagnostic ratios revealed that vehicle exhaust, coal and natural gas combustion were the main sources of PAHs in China. The estimated concentrations of PAHs were 3820 ng/L and 1120 ng/L in influents and effluents of the WWTPs, respectively. The high toxic equivalent quantity (TEQ) values of PAHs are ascribed to the high PAH levels. Risk quotient values (RQs) in sludge indicated that there was low potential risk to soil ecosystem after sludge had been applied one year except for indeno [1,2,3-cd]pyrene (IcdP) detected in Huaibei, Anhui province.

Effect of cetyltrimethyl ammonium bromide on uptake of polycyclic aromatic hydrocarbons by carrots

This is the first study investigating the effect of cationic surfactants on the mobility of polycyclic aromatic hydrocarbons (PAHs) in aged contaminated soils and on PAH bioaccumulation in tuberous vegetables. In an aerobic soil incubation experiment, 150 mg/kg cetyltrimethyl ammonium bromide (CTMAB) decreased the bioavailability of PAHs primarily via immobilization (by 13%). In a carrot pot experiment, the effectiveness of CTMAB to reduce PAH uptake by carrots decreased with time. Accordingly, the bioavailability of PAHs in the soil decreased in the first 90 days and then increased and remained stable until harvest. In the leaching test, the leaching loss of CTMAB (15%) was lower in soils treated with small amounts of CTMAB in several applications than it was in soils (24%) treated once with CTMAB. Therefore, CTMAB, when applied in appropriate doses via addition methods, can effectively reduce the environmental risk of PAH entering humans and livestock through the food chain.