Polycyclic aromatic hydrocarbons (PAHs) in dry tea leaves and tea infusions in Vietnam: contamination levels and dietary risk assessment

Using QuEChERS and HPLC Method to Monitor the Background Concentration of Polycyclic Aromatic Hydrocarbons in Commercial Black Tea Leaves and Infusions in Taiwan

Tea is an integral part of Taiwanese culture and is a popular drink as it contains many beneficial compounds. However, during the processing of tea, polycyclic aromatic hydrocarbons (PAHs) may form. This study investigated the concentrations of PAH4 in different black tea leaves and tea infusions based on the origin of the tea. The samples were extracted using QuEChERS, while the content of PAH4 was analyzed by high performance liquid chromatography coupled to a fluorescence detector (HPLC-FLD). The content of PAH4 in the tea leaves ranged from 2.88 µg/kg to 218.2 µg/kg (dry weight), with the highest concentration being found in teas from Vietnam. The concentration of BaP ranged from ND to 47.92 µg/kg. The release of PAH4 from tea leaves to tea infusions was significantly low, with the highest transfer being 25.8%. In this study, all PAH4 compounds in commercial black tea leaves can be detected by QuEChERS extraction with a simple HPLC method.

Dietary Exposure and Health Risk Assessment of Polycyclic Aromatic Hydrocarbons in Black Tea Consumed in Taiwan

Polycyclic aromatic hydrocarbons (PAHs) are organic compounds found in many foods and drinks, and there have been some concerns over these compounds due to their carcinogenic nature. This study evaluated the concentrations of PAH4 (BaP, BaA, BbF, and CHR) in different black tea infusions and drinks based on the origin of the tea. The release of PAH4 from tea leaves to tea infusions was significantly low, with the highest transfer being 25.81%. The mean concentrations of BaP and PAH4 in tea infusions were used to conduct a risk assessment for the Taiwanese population, which showed that the 19-65 age group had the highest estimated intake of PAH4 and BaP among all age groups. These results, however, also showed margin of exposure (MOE) values well above the benchmark of 10,000. This indicated that PAH exposure from black tea consumption for the Taiwanese population constitutes a low-level health concern.

Concentrations of polycyclic aromatic hydrocarbons in Vietnamese takeaway coffee: effects of coffee variety, roasting temperature and time

The research goal was to estimate the level of risk to human health posed by polycyclic aromatic hydrocarbons (PAHs) in Vietnamese takeaway coffee. A variety of roasted coffee beans were collected and tested for the presence of PAHs in various takeaway locations throughout Vietnam. Furthermore, the effect of roasting conditions on PAH concentrations in Vietnamese Robusta coffee was also studied and demonstrated. Gas chromatography-mass spectrometry, a modern, accurate, and fast method, was used to determine the research results. Six PAHs, namely naphthalene, anthracene, pyrene, fluorene, phenanthrene, and benz[a]anthracene, were found in the 100 collected samples, with average concentrations (μg/kg dry weight) of 943.7 ± 40.3, 195.1 ± 4.9, 36.1 ± 1.1, 33.3 ± 2.2, 28.2 ± 1.7, and 2.0 ± 0.1, respectively. It was found that the tested samples were almost free of PAH4 contamination. The research showed that the total value of PAH quantifications in Robusta coffee increased with increasing roasting temperature and decreased with increasing roasting time. In addition, the calculated value of the total hazard quotient (THQ) was less than 1, and the obtained value of the incremental lifetime carcinogenic risk (ILCR) did not exceed 1·10^-5, meaning that coffee consumers in Vietnam are safe from exposure to PAHs present in the investigated coffee beans.

Concentration and risk assessment of PCNs in green tea in different locations in China

Polychlorinated naphthalenes (PCNs) were added to the Stockholm Convention list of persistent organic pollutants in 2015. PCNs are mainly unintentionally produced during industrial processes nowadays, and can be widely found in environmental media and foodstuffs. Dietary intake is the primary pathway for human exposure to PCNs. PCNs in different categories of foodstuffs have been reported. However, little information on PCN concentrations in green tea, a popular beverage worldwide is available. In this study, all 75 PCN congener concentrations and distributions in green tea samples (n = 102) from 11 regions in China were determined, and risk assessment of human exposure to PCNs through tea consumption was conducted. The PCN concentrations in all the green tea samples were 3.62-175 pg/g dry weight (mean 36.1 pg/g dry weight). Similar PCN homolog and congener profiles were found in green tea samples from different areas. The dominant PCN homologs in all of the green tea samples were di-CNs, tetra-CNs, and tri-CNs. No direct relationships were found between PCN emission sources and PCN concentrations in the green tea samples. The brewing technique could affect the PCN concentrations and homolog profiles in tea leaves. PCNs in green tea from China were found to pose little risk to humans.

Comparative Analysis of Polycyclic Aromatic Hydrocarbons and Halogenated Polycyclic Aromatic Hydrocarbons in Different Parts of Perilla frutescens (L.) Britt

Perilla frutescens (L.) Britt., a medicinal herb and edible plant, is very popular among East Asian countries. The perilla leaves, stems and seeds can be used as traditional medicines and foods. Polycyclic aromatic hydrocarbons (PAHs) and halogenated PAHs (HPAHs) are organic pollutants that are widely present in the environment, such as in water, air and soil, and are harmful to humans. In this study, the contents of 16 PAHs and 4 HPAHs in perilla leaves, stems and seeds were determined by gas chromatography tandem mass spectrometry (GC-MS). A total of 12 PAHs were detected in all samples, and no HPAHs were detected. The total contents of PAHs in perilla leaves, stems and seeds varied from 41.93 to 415.60 ng/g, 7.02 to 51.52 ng/g and 15.24 to 180.00 ng/g, respectively. The statistical analyses showed that there were significant differences in the distribution of PAHs in perilla leaves, stems and seeds. On the basis of the toxic equivalent quantity (TEQ) and incremental lifetime cancer risk (ILCR) model, the cancer risks of the intake of perilla leaves, stems and seeds were assessed to be from 3.30 × 10⁻⁸ to 2.11 × 10⁻⁵, 5.52 × 10⁻⁹ to 5.50 × 10⁻⁸ and 1.20 × 10⁻⁸ to 1.41 × 10⁻⁷, respectively. These were lower than 10⁻⁴ (the priority risk level of the EPA) and suggested that there may be almost no cancer risk from the intake of these traditional Chinese medicines (TCMs).

Determination of Glyphosate, Glufosinate, and Their Major Metabolites in Tea Infusions by Dual-Channel Capillary Electrophoresis following Solid-Phase Extraction

In this study, two analytical procedures were developed and validated using dual-channel capillary electrophoresis-coupled contactless conductivity detection (CE-C4D) followed by solid-phase extraction (SPE) for simultaneous determination of glyphosate (GLYP), glufosinate (GLUF), and their two major metabolites, aminomethylphosphonic acid (AMPA) and 3-(methylphosphinico) propionic acid (MPPA), respectively, in a popular beverage such as tea infusions. GLYP, GLUF, and AMPA were analyzed in the first channel using background electrolyte (BGE) of 1 mM histidine (His) adjusted to pH 2.75 by acetic acid (Ace). In contrast, MPPA was quantified in the second channel with a BGE of 30 mM His adjusted to pH 6.7 by 3-(N-morpholino) propanesulfonic acid (MOPS) and 10 µM of cetyltrimethylammonium bromide (CTAB). In addition, the samples of tea infusions were treated using SPE with 10 mL of 0.5 mM HCl in methanol as eluent. At the optimized conditions, the method detection limit (MDL) of GLYP, GLUF, AMPA, and MPPA is 0.80, 1.56, 0.56, and 0.54 μg/l, respectively. The methods were then applied to analyze four target compounds in 16 samples of tea infusions. GLYP was found in two infusion samples of oolong tea with concentrations ranging from 5.34 to 10.74 µg/L, and GLUF was recognized in three samples of green tea infusion in the range of 45.1-53.9 µg/L.

Polycyclic Aromatic Hydrocarbons (PAHs) Sample Preparation and Analysis in Beverages: A Review

The monitoring of food contaminants is of interests to both food regulatory bodies and the consumers. This literature review covers polycyclic aromatic hydrocarbons (PAHs) with regard to their background, sources of exposures, and occurrence in food and environment as well as health hazards. Furthermore, analytical methods focusing on the analysis of PAHs in tea, coffee, milk, and alcoholic samples for the last 16 years are presented. Numerous experimental methods have been developed aiming to obtain better limits of detections (LODs) and percent recoveries as well as to reduce solvent consumption and laborious work. These include information such as the selected PAHs analyzed, food matrix of PAHs, methods of extraction, cleanup procedure, LOD, limits of quantitation (LOQ), and percent recovery. For the analysis of tea, coffee, milk, and alcoholic samples, a majority of the research papers focused on the 16 US Environmental Protection Agency PAHs, while PAH4, PAH8, and methylated PAHs were also of interests. Extraction methods range from the classic Soxhlet extraction and liquid–liquid extraction to newer methods such as QuEChERS, dispersive solid-phase microextraction, and magnetic solid-phase extraction. The cleanup methods involved mainly the use of column chromatography and SPE filled with either silica or Florisil adsorbents. Gas chromatography and liquid chromatography coupled with mass spectrometry or fluorescence detectors are the main analytical instruments used. A majority of the selected combined methods used are able to achieve LODs and percent recoveries in the ranges of 0.01–5 ug/kg and 70–110%, respectively, for the analysis of tea, coffee, milk, and alcoholic samples.

Polycyclic Aromatic Hydrocarbon Risk Assessment and Analytical Methods Using QuEchERS Pretreatment for the Evaluation of Herbal Medicine Ingredients in Korea

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and mutagenic compounds that are often formed during the thermal processing of herbal medicine ingredients. In this study, the concentrations of four PAHs (PAH4) in various herbal medicine ingredients were monitored. Further, the QuEChERS method was used to replace conventional pretreatment, a more complex and cumbersome approach. The recovery range of the QuEChERS method ranged between 89.65–118.59%, and the average detection levels of benzo[a]anthracene (BaA), chrysene (CHR), benzo[b]fluoranthene (BbF), and Benzo[a]pyrene (BaP) in 50 herbal medicine ingredients were 0.18, 0.27, 1.13, and 0.17 μg/kg, respectively. The BaP and PAH4 levels in all tested samples were deemed safe according to risk characterization analyses based on European Union and Korean guidelines. Therefore, our findings indicated that the QuEChERS method could be used as an effective alternative to conventional sample pretreatment for the analysis of herbal medicine ingredients.

Effects of manufacturing procedures and preparation conditions on European Union priority polycyclic aromatic hydrocarbons in Oolong tea samples

The study evaluated the changes in polycyclic aromatic hydrocarbons (PAHs) of Oolong tea samples at each heat treatment stage of the manufacturing process, different post-treatment methods and different brewing conditions. The content of PAHs in the tea leaves was significantly increased during stir fixation (280 °C for 8 min) stage of the manufacturing process. In the subsequent heat treatment process, the PAHs content did not change much until the Oolong tea product (primary) was further roasted. The level of PAHs increased with the roasting time. Charcoal roasting resulted in higher PAHs content in the product compared with electric roasting. Higher brewing temperature caused higher level of PAHs released into the tea infusion. The level of released PAHs decreased with the increase of the number of tea brewing (the total released PAHs was about 4%). The risk assessment results for PAHs in the tea infusions showed a low level of health concern.

Persistent organic pollutants (PCBs and PCDD/Fs), PAHs, and plasticizers in spices, herbs, and tea - A review of chromatographic methods from the last decade (2010-2020)

Edible and highly demanded plant-derived products such as herbs, spices, and tea may be subjected to exogenous contamination of well-known chemical hazards such as persistent organic pollutants (POPs), and emerging ones such as plasticizers, affecting negatively the safety of these food commodities. This fact has led to the increasing analysis of exogenous compounds including priority POPs such as polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs), as well as highly persistent polycyclic aromatic hydrocarbons (PAHs). Currently, plasticizer residues are also considered an emerging issue because of the extensive use in food packaging and potential migration into foodstuffs. In this review, the studies published from 2010 to 2020 were discussed, including the main extraction methods applied for these contaminants from herbs, spices, and tea, and it was revealed the trend toward the use of less solvent-consuming and time-effective methods. Chromatographic methods were also described, which were mainly combined with detection techniques such as classical or mass spectrometry (MS) detection. Finally, a comprehensive overview of the occurrence of these selected exogenous compounds was presented in the studied matrices, showing that their monitoring should be further investigated to ensure food safety of highly consumed condiments and tea.