Comparison of different digestion methods of green and black tea at the Sarajevo market for the determination of the heavy metal content

The content of Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn was determined in commercially available black and green tea from Sarajevo market. The concentrations of metals in tea infusion and solutions prepared by applying four digestion methods were determined by using FAAS. The results show that the highest concentration of total metals was obtained after acid digestion in an autoclave. The concentration of metals soluble in water obtained in tea infusion does not exceed maximum allowed values provided by WHO (Guidelines for drinking-water quality, World Health Organization, Geneva, 2011). Among the investigated metals Mn was the highest and ranged from 286 to 334 μg g^?1 in tea infusion of green and black tea, respectively, to 1,078 and 1,528 μg g^?1 total content of Mn in green and black tea, respectively. The concentration of heavy metals in water extracts of tea was distinctly low in comparison with the total content. The concentrations of Cd and Pb were under the determination limit using FAAS. The total content of all determined metals was higher in black tea than in green tea.     

Heavy metals in vegetables and respective soils irrigated by canal,municipal waste and tube well waters

Heavy metal contamination in the food chain is of serious concern due to the potential risks involved. The results of this study revealed the presence of maximum concentration of heavy metals in the canal followed by sewerage and tube well water. Similarly, the vegetables and respective soils irrigated with canal water were found to have higher heavy metal contamination followed by sewerage- and tube-well-watered samples. However, the heavy metal content of vegetables under study was below the limits as set by FAO/WHO, except for lead in canal-water-irrigated spinach (0.59 mg kg^?1), radish pods (0.44 mg kg^?1) and bitter gourd (0.33 mg kg^?1). Estimated daily intakes of heavy metals by the consumption of selected vegetables were found to be well below the maximum limits. However, a complete estimation of daily intake requires the inclusion of other dietary and non-dietary exposure sources of heavy metals.     

Tea and Its Consumption: Benefits and Risks

The recent convention of introducing phytochemicals to support the immune system or combat diseases is a centuries’ old tradition. Nutritional support is an emerging advancement in the domain of diet-based therapies; tea and its constituents are one of the significant components of these strategies to maintain the health and reduce the risk of various malignancies. Tea is the most frequently consumed beverage worldwide, besides water. All the three most popular types of tea, green (unfermented), black (fully fermented), and oolong (semifermented), are manufactured from the leaves of the plant Camellia sinensis. Tea possesses significant antioxidative, anti-inflammatory, antimicrobial, anticarcinogenic, antihypertensive, neuroprotective, cholesterol-lowering, and thermogenic properties. Several research investigations, epidemiological studies, and meta-analyses suggest that tea and its bioactive polyphenolic constituents have numerous beneficial effects on health, including the prevention of many diseases, such as cancer, diabetes, arthritis, cardiovascular disease (CVD), stroke, genital warts, and obesity. Controversies regarding beneficialts and risks of tea consumption still exist but the limitless health-promoting benefits of tea outclass its few reported toxic effects. However, with significant rise in the scientific investigation of role of tea in human life, this review is intended to highlight the beneficial effects and risks associated with tea consumption.     

Micronutrients (B,Co, Cu,Fe, Mn,Mo, and Zn) content in made tea (Camellia sinensis L.) and tea infusion with health prospect: A critical review

Tea (Camellia sinensis L.) is a perennial acidophilic crop, and known to be a nonalcoholic stimulating beverage that is most widely consumed after water. The aim of this review paper is to provide a detailed documentation of selected micronutrient contents, viz. boron (B), cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn) in made tea and tea infusion. Available data from the literature were used to calculate human health aspect associated with the consumption of tea infusion. A wide range of micronutrients reported in both made tea and tea infusion could be the major sources of micronutrients for human. The content of B, Co, Cu, Fe, Mn, Mo, and Zn in made tea are ranged from 3.04 to 58.44 μg g^?1, below detectable limit (BDL) to 122.4 μg g^?1, BDL to 602 μg g^?1, 0.275 to 13,040 μg g^?1, 0.004 to 15,866 μg g^?1, 0.04 to 570.80 μg g^?1 and 0.01 to 1120 μg g^?1, respectively. Only 3.2 μg L^?1 to 7.25 mg L^?1, 0.01 μg L^?1 to 7 mg L^?1, 3.80 μg L^?1 to 6.13 mg L^?1, 135.59 μg L^?1 ?11.05 mg L^?1, 0.05 μg L^?1 to 1980.34 mg L^?1, 0.012 to 3.78 μg L^?1, and 1.12 μg L^?1 to 2.32 μg L^?1 of B, Co, Cu, Fe, Mn, Mo, and Zn, respectively, are found in tea infusion which are lower than the prescribed limit of micronutrients in drinking water by World Health Organization. Furthermore, micronutrient contents in tea infusion depend on infusion procedure as well as on the instrument used for analysis. The proportion of micronutrients found in different tea types are 1.0–88.9% for B, 10–60% for Co, 2.0–97.8% for Cu, 67.8–89.9% for Fe, 71.0–87.4% for Mn, 13.3–34% for Mo, and 34.9–83% for Zn. From the results, it can also be concluded that consumption of three cups of tea infusion per day does not have any adverse effect on human health with respect to the referred micronutrients rather got beneficial effects to human.     

Metal levels in Trachurus trachurus and Cyprinus carpio in Turkey

Concentrations of five toxic metals were determined in two fish species from Turkish cities during 2010–2011. The obtained lead concentrations for all of the studied Trachurus trachurus (mean 777 μg kg^?1) and Cyprinus carpio (mean 439 μg kg^?1) samples were found to be higher than the maximum level (ML) of 300 μg kg^?1, while Cd concentrations in the same samples were lower than the ML. Mean chromium (501 μg kg^?1), Ni (272 μg kg^?1) and Cu (785 μg kg^?1) concentrations in T. trachurus were significantly higher than in C. carpio (336 μg Cr kg^?1, 229 μg Ni kg^?1 and 394 μg Cu kg^?1), similar to those of Pb and Cd. Measured Pb concentrations in T. trachurus tissues are significantly higher than the ML, while those of Cd in both T. trachurus and C. carpio species were lower than the ML values.     

Soil and vegetable compositional relationships of eight potentially toxic metals in urban garden fields from northern Nigeria

BACKGROUND: Human exposure to heavy metals is attributed to consumption of vegetables raised in polluted soil environment. We examined the concentrations of As, Cd, Co, Cr, Cu, Ni, Pb and Zn in soils and lettuce (Latuca sativa) and amaranthus (Amaranthus caudatus) in 15 garden fields under long‐term wastewater irrigation. RESULTS: The concentrations of As (0.3–2.1 mg kg^?1), Cd (0.07–0.3 mg kg^?1), Co (4.6–9.1 mg kg^?1) and Cr (21.6–36.2 mg kg^?1) in the gardens were consistent with background concentrations in soils, but Ni (12.6–25.7 mg kg^?1), Cu (12.5–24.6 mg kg^?1), Pb (25.7–71.6 mg kg^?1) and Zn (52.3–158 mg kg^?1) concentrations were double the concentrations normally encountered in arable fields in the region. The concentrations of Cd and As in the vegetables were within safe limits, but Co (0.14–0.67 mg kg^?1 fresh weight (fw)) and Ni (1.0–2.7 mg kg^?1 fw) concentrations in lettuce were relatively high for leaf vegetables. The concentration of Pb (0.65–4.80 mg kg^?1 fw) was above safe limit of 0.3 mg kg^?1 fw, while the concentrations of Cu (1.3–2.7 mg kg^?1 fw and Zn (10.2–23.6 mg kg^?1 fw) were close to the unsafe limits for leaf vegetables. There were no strong linear correlations between soil metal concentrations and bio‐concentrations in the vegetable crops. CONCLUSION: We surmise that leaf vegetables can accumulate metals in their tissues to unsafe levels even when total metal concentrations in these soils are below the allowable concentrations in agricultural soils. Copyright © 2008 Society of Chemical Industry     

Tea caffeine: Metabolism, functions, and reduction strategies

Tea is a product made up from topmost part of the plant Camellia sinensis. This part includes bud, first leaf (next to bud), second leaf, and stem (spanning from bud to second leaf). Tea is the second most consumed beverage in the world, well ahead of coffee, beer, wine, and carbonated soft drinks. Clinical studies have demonstrated that one of the harmful effects of tea over consumption, at least in sensitive peoples is due to its caffeine content. In view of this, major points discussed in this article are the following: i) a brief overview on tea and its biochemical composition, ii) health effects of tea drink, iii) caffeine metabolism and its functions, iv) possible strategies for caffeine reduction in tea, and v) feasibility of tea improvement through biotechnological approaches.     

饮茶和食管癌关系的研究进展

茶是除水以外消耗最多的一种饮料,在日常生活中随处可见。茶多酚是茶叶中主要的活性成分之一,研究表明,茶多酚具有抗氧化、抗肿瘤等作用,可作为癌症的保护因素。而喜食烫食可能会损伤食管黏膜,使食道上皮细胞脱落、更新加快,从而增加食管癌的发病风险。关于饮茶与食管癌关系的研究至今还没有得到一致的结论。本文主要从茶的消耗量、茶的种类、饮茶温度3 方面对近年来茶和食管癌关系的研究进行综述,并对未来的研究重点进行展望。     

Temperature and Time of Steeping Affect the Antioxidant Properties of White,Green, and Black Tea Infusions

Tea (Camellia sinensis) is the most highly consumed beverage in the world next to water. The common way of preparation is steeping in hot water which is varying for different type of tea. We investigated the antioxidant properties of 6 type of tea leaves under different time and temperatures of extraction method used. In general, all samples tested in this study demonstrated high levels of antioxidant capacity and antioxidant activity. The results indicate that the antioxidants activity is significantly affected by time and temperature of steeping and the highest was depending on the variety. White state values, green and black teas showed different levels of antioxidants under different extraction conditions. Overall, the highest activity for white tea was in prolonged hot and in some assays prolonged hot and cold extracts, whereas for green tea the highest activity observed in prolonged cold steeping while, for black tea was in short hot water infusion. The results of this study showed the antioxidant capacity of white and green tea was greater than black tea.     

Determination of 16 phthalate esters in tea samples using a modified QuEChERS sample preparation method combined with GC-MS/MS

A modified QuEChERS method for the determination of 16 phthalate esters (PAEs) in tea samples using GC-MS/MS was developed and validated. The kinds and amounts of adsorbents were optimised, and the crude extracts were purified using primary secondary amine (PSA), graphitised carbon black (GCB) and anhydrous magnesium sulphate (MgSO₄). Compared with extraction without matrix hydration, the addition of water could achieve higher extraction efficiency. The recoveries for PAEs obtained against matrix-matched standards at spiking levels of 50, 200 and 500 μg kg^–1 ranged from 84.7% to 112.7% with relative standard deviations below 20% (n = 6) for all cases. Limits of detection (0.6–36.0 μg kg^–1) and quantitation (2.0–120.0 μg kg^–1) were achieved using the proposed method for all PAEs. A total of 105 tea samples were found to be contaminated with PAEs.     

Tea flavonoids: their functions,utilisation and analysis

The three main categories of tea: green, black and oolong, result from different processing procedures. In recent years tea has attracted more and more attention because of reported health benefits, in particularly as an antioxidant, but also as an anticarcinogenic and antiarteriosclerotic agent. It is generally believed that flavonoids are mainly responsible for these actions. Tea is now consumed throughout the world not just as a popular beverage, but, because its extracts have been prepared in a variety of physical forms, for example, strong infusions, soft extracts and powders, it is now widely available in a range of food, beverage, and toiletry and cosmetic products.     

Heavy metals in vegetables sold in the local market in Jordan

Heavy metals (As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn) in various vegetables (cabbage, green onion, lettuce, parsley, rocket, spinach, carrot, onion, potato and cauliflower) from the market in Jordan were measured using inductively coupled plasma-mass spectrometry. As, Cd, Co, Cr, Cu, Mn, Ni, Pb and Zn ranged from 0.009–0.275 mg kg^?1 wet weight, 0.004–0.060 mg kg^?1, 0.003–0.401 mg kg^?1, 0.105–3.51 mg kg^?1, 0.15–1.15 mg kg^?1, 0.93–14.39 mg kg^?1, 0.044–0.702 mg kg^?1, 0.072–0.289 mg kg^?1 and 2.23–6.65 mg kg^?1, respectively. Parsley, followed by spinach, contained the highest concentration of heavy metals. Onion contained high levels of toxic heavy metals. The content of Cu in parsley and spinach and Pb in onion exceeded the Codex limits. However, the daily intake of heavy metals from the tested vegetables was lower than the maximum limits for allowable intake.     

Application of different forms of calcium to tea soil to prevent aluminium and fluorine accumulation

Tea Camellia sinensis (L), is a well‐known accumulator of aluminium and fluorine from acidic soil. A reduction is desirable as aluminium and fluorine absorbed will leach into the tea liquor through infusion, thus posing a serious threat to the health of consumers. The present study aims to investigate the effects of adding different forms of calcium on Al and F uptake by tea plants, in order to reduce the concentrations of these elements contained in the plants. All true lime materials increased the soil pH and decreased soil extractable Al and F concentrations. There were no (p < 0.05) changes in pH values when CaCl₂ was added, and a slight decrease in Al and F concentrations was observed in the treatments with CaSO₄. Tea seedlings under the addition of CaSO₄ were the tallest and healthiest, followed by CaCl₂, CaCO₃, Ca(OH)₂ and CaO. Seedlings under large doses of Ca(OH)₂ and CaO were dead. Relative growth rates decreased significantly with the increase of calcium compounds except in CaSO₄ treatment. The highest Al concentration was also found in the treatment of 4000 mg CaSO₄ kg^?1; it then decreased gradually from 3364 to 933 mg Al kg^?1 in leaves. For all treatments in both varieties, F concentrations in leaves were lower than the control (374 mg kg^?1). Calcium chloride was a suitable agent for reduction of Al and F uptake by tea plants while maintaining a high growth rate of the seedlings. Copyright © 2004 Society of Chemical Industry     

Identifications of inhibitors of IgE production by human lymphocytes isolated from ‘Cha Chuukanbohon Nou 6’ tea leaves

BACKGROUND: Tea (Camellia sinensis L.) is consumed all over the world and in especially large quantities in Japan and China, where it has been used not only as a daily beverage but also for medicinal purposes for thousands of years. Tea has been found to exhibit various bioregulatory activities, including antiallergic, anticarcinogenic, antimetastatic, antioxidative, antihypertensive, antihypercholesterolemic, anti‐dental caries and antibacterial effects, and to influence intestinal flora. RESULTS: Cha Chuukanbohon Nou 6 is a tea cultivar improved by the National Institute of Vegetable and Tea Science (NIVTS) in Japan. On comparing chemical constituents of 11 varieties of tea leaves by high‐performance liquid chromatography, we found two new major compounds in Cha Chuukanbohon Nou 6. Nuclear magnetic resonance spectroscopy revealed these compounds to be theogallin and 1,2‐di‐O‐galloyl‐4,6‐O‐(S)‐hexahydroxydiphenoyl‐β‐D ‐glucopyranose. The two were similar in chemical structure to strictinin, an inhibitor of immunoglobulin (Ig) production. Thus their effects on the production of Igs by peripheral blood lymphocytes were tested. Both compounds, like strictinin, inhibited IgE production. CONCLUSION: The results suggest Cha Chuukanbohon Nou 6 to be the basis of an antiallergic beverage. Copyright © 2009 Society of Chemical Industry     

茶叶质量安全主要化学影响因素分析方法研究进展

茶叶是一种很受欢迎的饮料作物,具有独特的香气、药用及保健功效,深受消费者喜爱。现代工业的迅速 发展和化肥、农药的大量使用造成了严重的环境污染、生态破坏等问题,导致茶叶质量安全受到严重威胁,引起社 会的广泛关注。本文总结相关文献,从茶叶样品的前处理技术和检测技术两个方面,对影响茶叶质量安全的主要化 学因素农药残留、重金属残留和真菌毒素的分析方法进行了总结,对各方法的优缺点进行了比较,并对未来的发展 趋势进行了展望,以期为今后开展相关的检测研究提供参考。     

Leaching of residues of certain pesticides from black tea to brew

Tea is the most commonly consumed beverage in the world. It is prepared after infusing processed black tea in hot water. During the process of brewing, along with flavour and aroma, the residues of plant protection chemicals may also be transferred into the tea brew or infusion. The leaching of certain pesticides, such as ethion, endosulfan, dicofol, chlorpyrifos, deltamethrin, hexaconazole, fenpropathrin, propargite, quinalphos and lambdacyhalothrin from powdered black tea into the brew was studied. The rate of transfer of the pesticide residue from black tea to the hot brew was largely influenced by physicochemical parameters, such as water solubility and octanol-water partition coefficient. Tea brews prepared from untreated black tea samples were fortified with standard solutions of the respective pesticides, extracted and analysed using GC and HPLC by following standardised methods. Results revealed that the rate of leaching of residues of these pesticides into the tea brew was low due to their low solubilities in aqueous medium and high octanol-water partitioning coefficients.     

Preventive effects of black tea theaflavins against mouse type IV allergy

BACKGROUND: Tea (Camellia sinensis L.), one of the most popular beverages, contains various beneficial constituents. We investigated the preventive effects of black tea theaflavins, theaflavin‐3‐gallate (3‐TF) and theaflavin‐3,3′‐digallate (TFDG), on oxazolone‐induced type IV allergy in male ICR mice. RESULTS: Percutaneous administration of both 3‐TF and TFDG at 0.2 mg ear^?1 showed significant preventive effects against mouse type IV allergy. Oral administration of these agents at 50 mg kg^?1 body weight also showed significant preventive effects against mouse type IV allergy. Oral administration of 3‐TF and TFDG at a dose of 50 mg kg^?1 body weight prevented the increases in levels of some proinflammatory cytokines, interleukin‐12 (IL‐12), interferon‐gamma (IFN‐γ), and tumour necrosis factor‐alpha (TNF‐α), in the sera and/or ears of mice with type IV allergy. Lowering of serum antioxidant activity in mice with allergic symptoms was also prevented by oral administration of these theaflavins at a dose of 50 mg kg^?1 body weight. The anti‐allergic mechanisms of action of theaflavins involve inhibition of the fluctuations of cytokines and maintenance of antioxidant status in allergic mice. CONCLUSION: These results suggest that the theaflavins as well as catechins contribute to the anti‐allergic effects of black tea. Copyright © 2010 Society of Chemical Industry     

Determination of pyrrolizidine alkaloids in tea,herbal drugs and honey

Honey was previously considered to be one of the main food sources of human pyrrolizidine alkaloid (PA) exposure in Europe. However, comprehensive analyses of honey and tea sampled in the Berlin retail market revealed unexpected high PA amounts in teas. This study comprised the analysis of 87 honey as well as 274 tea samples including black, green, rooibos, melissa, peppermint, chamomile, fennel, nettle, and mixed herbal tea or fruit tea. Total PA concentrations in tea ranged from < LOD to 5647 µg kg^?1, while a mean value of about 10 µg kg^?1 was found in honey samples. Additionally, herbal drugs were investigated to identify the source of PA in teas. Results suggest that PA in tea samples are most likely a contamination caused by co-harvesting of PA-producing plants. In some cases such as fennel, anise or caraway, it cannot be excluded that these plants are able to produce PA themselves.     

Validation of a LC–MS Method for the Determination of Urea Contamination in Market Teas

Tea is one of the most widely consumed beverages in the world preceded only by water. In some culture style of tea plant, urea fertilizer is sprayed on tea leaf in order to increase crop output; besides, in some processing method of green tea, urea is illegally added to maintain tea’s vivid color. The above-mentioned process may unavoidably cause urea residue, and prolonged or repeated exposure of body to urea may cause adverse effects. In this work, an easy and reliable hydrophilic interaction liquid chromatography/mass spectrometry analytical method for determination of urea in tea was firstly validated; the method exhibited a linear response from 4 to 60 μg mL^?1 (R ²?>?0.9996), the limit of quantitation for urea is 4 μg mL^?1, the mean recoveries of urea spiked at levels of 10 and 20 μg mL^?1 were 95–110 %, and the relative standard deviations of intra- and inter-day measurements were less than 7.8 %. The method was later successfully applied to the analysis of urea residue in some market tea samples. The result showed that there is obvious urea contamination in some market teas, and the contamination percentage is especially high in green tea samples. Among the samples investigated, urea was detected at concentration ranges of 24.02–46.02 mg/kg. Some attention should be paid on the health effect resulting from such urea contamination in tea.     

Energy drink consumption and impact on caffeine risk

The impact of caffeine from energy drinks occurs against a background exposure from naturally occurring caffeine (coffee, tea, cocoa and foods containing these ingredients) and caffeinated beverages (kola-type soft drinks). Background caffeine exposure, excluding energy drinks, was assessed for six New Zealand population groups aged 15 years and over (n = 4503) by combining concentration data for 53 caffeine-containing foods with consumption information from the 2008/09 New Zealand Adult Nutrition Survey (ANS). Caffeine exposure for those who consumed energy drinks (n = 138) was similarly assessed, with inclusion of energy drinks. Forty-seven energy drink products were identified on the New Zealand market in 2010. Product volumes ranged from 30 to 600 ml per unit, resulting in exposures of 10–300 mg caffeine per retail unit consumed. A small percentage, 3.1%, of New Zealanders reported consuming energy drinks, with most energy drink consumers (110/138) drinking one serving per 24 h. The maximum number of energy drinks consumed per 24 h was 14 (total caffeine of 390 mg). A high degree of brand loyalty was evident. Since only a minor proportion of New Zealanders reported consuming energy drinks, a greater number of New Zealanders exceeded a potentially adverse effect level (AEL) of 3 mg kg^?1 bw day^?1 for caffeine from caffeine-containing foods than from energy drinks. Energy drink consumption is not a risk at a population level because of the low prevalence of consumption. At an individual level, however, teenagers, adults (20–64 years) and females (16–44 years) were more likely to exceed the AEL by consuming energy drinks in combination with caffeine-containing foods.