Contamination of Tea and Tea Infusion with Polycyclic Aromatic Hydrocarbons

Exploring tea and herbal infusions consumption patterns and behaviours: The case of Portuguese consumers

Consumption of tea and herbal infusions (THIs) have a long history in traditional medicine and cultural practices. The health-promoting benefits attributed to THIs are considered influential factors in consumer choices. However, there is limited data on consumer choices and attitudes that might interfere with the positive effects associated with THIs consumption. The aim of this study was to investigate the consumption pattern and behavior of THIs consumers in Portugal, assessing the influence of socio-demographic factors on the selection of THIs products and consumer practices related to these beverages. An online survey was conducted, and from the collected data, 720 responses met the aim of the study and were further analyzed. Most of the respondents were female, 74.4%, belonging to the 40-60 age group (40.6%) and were medium consumers of THIs (47.2%). Green tea was the most consumed type among participants, and its consumption was associated not only with age but also with the pattern of THIs consumption. Despite that, participants preferred herbal infusions, with citronella, chamomile, and lemon verbena being the most consumed types. For certain types of herbal infusions, consumption was associated with age, while other types were preferred by moderate or heavy consumers. Most participants purchased THIs in supermarkets, registered trademark and brand stores, in the form of THIs bag. Light consumers use only bag, while medium/heavy consumers indicated the use of other forms. Almost half of the respondents admitted to not reading the information on product labels before consumption and using THIs after the expiry date, while only one-third of them declared paying attention to the label instructions. This study revealed the impact of socio-demographic factors as age on the consumption patterns and preferences of THIs of consumers. Of concern is the neglect of label usage among Portuguese consumers. This emphasizes the urgency of implementing interventions to guide proper label use and promote good consumption practices to ensure the quality of THIs products.

Antioxidant and inflammatory-modulating properties of ginger and bitterleaf teas

The present study evaluated the effects of ginger and bitterleaf tea infusions on redox and inflammatory balance in rats. Twenty-four Wistar rats with weights of between 160 and 180 g were assigned into four (4) groups (n = 6). The control group received distilled water, while the remaining groups were administered tea infusions of ginger, bitterleaf, or a combination of both at 5 mg/mL, respectively. Bitterleaf and ginger teas elevated the levels of superoxide dismutase, catalase, glutathione peroxidase, and reduced glutathione in rat plasma and liver, while malondialdehyde levels decreased. Furthermore, ginger tea caused an increase in the expression of nuclear factor erythroid-2-related factor 2 (Nrf-2) and reduced tumor necrosis factor alpha (TNF-α). The GC-MS analysis of the teas identified 77 chemical compounds, among which gingerol and precocene I were predominant. Collectively, the findings indicate, in particular, that ginger tea may boost antioxidant and anti-inflammatory capacity by increasing Nrf-2 levels.

Chemical fingerprinting, comparative in vitro antioxidant properties, and biochemical effects of ginger and bitterleaf infusion

Botanicals with remarkable pharmacological properties include Zingiber officinale Roscoe [Zingiberaceae] (ginger) and Gymnanthemum amygdalinum (Delie) Sch. Bip [Asteraceae] (bitterleaf). The plants are frequently used as teas and decoctions, and have been studied in the treatment of various illnesses. Thus, this study investigated the in vitro antioxidant activities and chemical fingerprints of ginger and bitter leaf infusions separately and as a combination. In addition, we assessed the effects of the tea infusions on rat liver and kidney indices. The findings from this study showed that the bitterleaf infusion had the highest phenolic content (21.77 ± 3.140 µg gallic acid equivalent/mg) in comparison with that of ginger (15.17 ± 1.50 µg gallic acid equivalent/mg) and their combination (8.81 ± 0.48 µg gallic acid equivalent/mg). The ginger infusion had the highest flavonoid content (547.15 ± 1.17 µg quercetin equivalent/mg), which was preceded by bitterleaf (473.02 ± 10.48 µg quercetin equivalent/mg) and the ginger and bitterleaf infusion (415.08 ± 4.15 µg quercetin equivalent/mg). Furthermore, our results showed that the tea infusions had no significant effect on the liver function indices (ALT and AST) compared to the control. In contrast, the rat plasma urea significantly increased in the groups given bitterleaf and a combination of ginger and bitterleaf infusions, while creatinine significantly decreased in the group that received the combined form of the infusion. The GC-MS analysis of ginger and bitterleaf infusions revealed that n-hexadecanoic acid, oleic acid, and ergosterol were most abundant in the bitterleaf infusion. At the same time, gingerol, 2-butanone, and 4-(4-hydroxy-3-methoxyphenyl) were the most abundant in the ginger infusion. Together, the findings are not only evidence in support of the medicinal value of these plants but also reinforce their prospects as nutriceuticals.

Zingiber officinale and Vernonia amygdalina Infusions Improve Redox Status in Rat Brain

The study investigated the effects of Zingiber officinale root and Vernonia amygdalina leaf on the brain redox status of Wistar rats. Twenty-four (24) rats weighing 160 ± 20 g were randomly assigned into four (4) groups, each with six (6) rats. Animals in Group 1 (control) were orally administered distilled water (1 mL), while the test groups were orally administered 5 mg/mL of either Z. officinale, V. amygdalina infusion, or a combination of both, respectively, for 7 days. The rats were sacrificed at the end of treatments and blood and tissue were harvested and prepared for biochemical assays. Results showed that administration of V. amygdalina and Z. officinale, as well as their coadministration, reduced the levels of malondialdehyde (MDA), nitric oxide (NO), acetylcholinesterase (AChE), and myeloperoxidase (MPO) in rat brain tissue compared with the control group. Conversely, coadministration of V. amygdalina and Z. officinale increased the levels of reduced glutathione (GSH) in rat brain tissue compared with the control group. However, the administration of the infusions singly, as well as the combination of both infusions, did not have any effect on the rat brain levels of glutathione peroxidase (GPx) and catalase (CAT) antioxidant enzymes compared to the control. Taken together, the findings indicate that the V. amygdalina and Z. officinale tea infusions have favorable antioxidant properties in the rat brain. The findings are confirmatory and contribute to deepening our understanding of the health-promoting effects of V. amygdalina and Z. officinale tea infusions.

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).

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.

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.

In-a-syringe surfactant-assisted dispersive liquid-liquid microextraction of polycyclic aromatic hydrocarbons in supramolecular solvent from tea infusion

In this work, an automated surfactant-assisted dispersive liquid-liquid microextraction approach based on in-a-syringe concept was developed for the first time. The procedure assumed mixing aqueous sample phase and hydrophilic emulsion containing hexanoic acid and sodium hexanoate in a syringe of flow system. Sodium hexanoate acted as an emulsifier in dispersive liquid-liquid microextraction process and it was required for the formation of supramolecular solvent phase. After spontaneous separation of phases in the syringe, the upper supramolecular solvent phase containing target analytes was withdrawn and analyzed. The procedure was applied to the determination of 13 polycyclic aromatic hydrocarbons in tea infusion by high performance liquid chromatography with fluorescence detection. It was shown that the supramolecular solvent provided effective extraction of polycyclic aromatic hydrocarbons and fast phase separation in the syringe without centrifugation. The enrichment factors were in the range of 38-46. The automated microextraction procedure lasted 4 min including syringe cleaning. Under optimal experimental conditions the linear detection ranges were found to be 0.05-50.00 μg L^-1 with limits of detection calculated from a blank test, based on 3σ, 0.02-0.04 μg L^-1. Recovery values in the range of 85-105% were achieved for tea infusion with a reproducibility expressed as RSD less than 4.1%.

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.

A novel dispersive liquid-liquid microextraction using a low density deep eutectic solvent-gas chromatography tandem mass spectrometry for the determination of polycyclic aromatic hydrocarbons in soft drinks

Ready-to-drink teas can provide, if properly packaged, the taste and wellness character of traditional teas. Nevertheless, in tea processing, there may be several contaminations, among which polycyclic aromatic hydrocarbons (PAHs), anthropogenic contaminants that can present carcinogenic and mutagenic properties. In this work, a novel low-density deep eutectic solvent-based dispersive liquid-liquid microextraction (LDDES-DLLME) procedure followed by gas chromatography tandem mass spectrometry (GC-MS/MS) was optimized for analysis of 15 polycyclic aromatic hydrocarbons (PAHs) in ready-to-drink herbal-based beverages. The new deep eutectic solvent (DES) was synthesized with natural compounds (camphor and hexanoic acid). Several parameters of the extraction procedure such as type and volume of extraction solvent, type, volume of dispersive solvent, and time of extraction were evaluated to achieve the highest yield and to attain the lowest detection limits. The validated method showed very low limits of detection (0.01 μg L^-1) and quantification (0.2 μg L^-1), good inter- and intra-day precisions (RSD<16.87%), and recoveries higher than 69%. The method was applied to 16 type of samples and it was found total PAHs levels ranging from 0.20 to 1.82 μg L^-1. The developed LDDES-DLLME showed a reliable and innovative alternative for the extraction of PAHs from beverages, cost-effective and environmentally friendly, and providing a satisfactory throughput.

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

The total mean ∑[Formula: see text] in samples were from 75.3 to 387.0 ng/g dry weight (d.w) and showed high value in black dry tea, followed by herbal, oolong, and green tea. The mean ∑[Formula: see text] (a combination of benz[a]anthracene, chrysene, benzo[b]fluoranthene, and benzo[a]pyrene) values were 54.3 ng/g, 16.4 ng/g, 14.2 ng/g, and 6.6 ng/g for black, herbal, green, and oolong teas, respectively. Concentration for benzo[a]pyrene (BaP) was from 0.4 to 35.8 ng/g, and the BaP equivalent concentration values ranged from 0.3 to 48.1 ng/g. There was only 1 black tea sample that BaP concentration exceeded the maximum level according to European Union (EU) standards. Tea samples marketed in Vietnam showed insignificant difference with the samples from other origins by same analytical method. Black teas showed high PAHs contents in dry tea samples but the released percentage of sum of PAHs from tea-to-tea infusion was lower than that in other tea type samples. The released percentages of PAH4 from tea-to-tea infusion were 40.7, 15.4, and 1.9 for green, herbal, and black tea. High temperature in black tea manufacturing processes might reduce essential oil content in tea that might effect on the PAHs partially release into the infusion. Indeed, based on EU regulations, we may conclude that tea consumers are safe in risk of exposure to PAHs obtained from teas.

Interactions of food matrix and dietary components on neonicotinoid bioaccessibility in raw fruit and vegetables

Humans are frequently exposed to the residues of various neonicotinoids, highlighting the need to understand human exposure through oral ingestion of contaminated foods. In this study, the effects of different food matrices (tomato, cucumber, and carrot) and their interaction with dietary component additives, including proteins and dietary fiber, was investigated. The results showed that the presence of a food matrix had a significant effect on the bioaccessibility of neonicotinoids (imidacloprid, thiamethoxam, acetamiprid, and thiacloprid) in both the gastric and intestinal environments. Neonicotinoids in tomato presented relatively low bioaccessibility, indicating that the daily intake of the tomato can be regarded as being relatively safer. Moreover, the addition of protein or dietary fiber to fruit and vegetables had a marked influence on neonicotinoid bioaccessibility and the effects varied between the different matrices. In particular, the addition of 2.0% dietary fiber significantly reduced the bioaccessibility (18.38-67.91%). Therefore, we recommend that consuming an increased intake of dietary fiber could improve the safety of fruit and vegetables in daily life. The present results can support the identification of suitable food intake conditions for the significant reduction of pesticide residue levels.