Aluminium and nutrients induce changes in the profiles of phenolic substances in tea plants (Camellia sinensis CV TTES, No. 12 (TTE))

BACKGROUND: Tea plants are always cultivated in acid soils in hilly regions and their growth can be dependent on to soluble aluminium (Al). The mechanism of Al detoxification and the influence of Al on phenolic compounds (i.e. catechin) in the roots of tea plants has remained obscure. This study aimed to investigate the influence of Al changes on the concentrations of phenolic substances in tea plants through hydroponic experiments. RESULTS: Tea plants were cultivated in nutrient solution containing 1.5 and 2.5 mmol L^?1 Al, and these treatments enhanced the growth of new buds and roots. Aluminium stimulated the uptake of Ca, Mg, K and Mn, whereas the uptake of Fe, Cu and Zn was retarded. Moreover, total phenol concentrations in tea plant tissues increased with increasing Al concentrations. In general, catechin concentrations in leaves increased with increasing Al concentrations in the hydroponic experiments. High correlation coefficients were obtained between Al and (?)‐ECG (r² = 0.85, P < 0.01) and between Al and total phenols (r² = 0.92, P < 0.01). CONCLUSIONS: The Al concentration in tea plants indeed increases catechin concentrations and plays an important role in the growth of tea plants. Copyright © 2011 Society of Chemical Industry     

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     

Formation of trihalomethanes in foods and beverages

Trihalomethanes (THMs) are suspected carcinogens and reproductive toxicants commonly found in chlorinated drinking water. This study investigates THM formation during the preparation of beverages and foods using chlorinated drinking water. A total of 11 foods and 17 beverages were tested. Under the experimental conditions, each food and beverage formed THMs, primarily chloroform, although low or trace levels of brominated THMs were also detected. Tea formed the highest THM levels (e.g., chloroform levels from 3 to 67 µg l^?1), followed by coffee (from 3 to 13 µg l^?1), rice (9 µg l^?1), soups (from 0.4 to 3.0 µg l^?1), vegetables (<1 µg l^?1), and baby food (<0.7 µg l^?1). Chloroform formation with instant tea, used as a highly reproducible model system, increased with free chlorine concentration, decreased with higher food (tea) concentration, and was unaffected by reaction (steeping) time and bromide ion concentration. These findings indicate that chlorine-food reactions are fast, but that formation decreases as the chlorine demand of the food system increases. THMs are formed in the preparation and cooking of a wide variety of foods if free chlorine is present, and our results suggest that tea can be a significant source of exposure to THMs.     

Determination of the caffeine contents of various food items within the Austrian market and validation of a caffeine assessment tool (CAT)

The caffeine content of 124 products, including coffee, coffee-based beverages, energy drinks, tea, colas, yoghurt and chocolate, were determined using RP-HPLC with UV detection after solid-phase extraction. Highest concentrations of caffeine were found for coffee prepared from pads (755?mg?l^?1) and regular filtered coffee (659?mg?l^?1). The total caffeine content of coffee and chocolate-based beverages was between 15?mg?l^?1 in chocolate milk and 448?mg?l^?1 in canned ice coffee. For energy drinks the caffeine content varied in a range from 266 to 340?mg?l^?1. Caffeine concentrations in tea and ice teas were between 13 and 183?mg?l^?1. Coffee-flavoured yoghurts ranged from 33 to 48?mg?kg^?1. The caffeine concentration in chocolate and chocolate bars was between 17?mg?kg^?1 in whole milk chocolate and 551?mg?kg^?1 in a chocolate with coffee filling. A caffeine assessment tool was developed and validated by a 3-day dietary record (r ^2?=?0.817, p?<?0.01) using these analytical data and caffeine saliva concentrations (r ^2?=?0.427, p?<?0.01).     

Effects of soil pH on the uptake of Al,F and other elements by tea plants

Soil extractable Al, F and Zn concentrations decreased whereas extractable Ca, Cu, K, Mg, Na and P concentrations increased when the soil pH was raised from 3 to 6. These trends led to a decrease in growth of tea seedlings as determined by measurements of relative dry weight gain (RDW), relative leaf number gain (RLN) and relative leaf area gain (RLA). Tea seedlings of both ‘large‐leafed’ and ‘small‐leafed’ varieties grown in soils at pH 3 and 3.5 were the tallest and healthiest, while those at pH 6 died after 3 months. The large‐leafed variety showed higher growth rates than the small‐leafed variety. The highest (p < 0.05) amounts of Al and F, 4225 and 430 mg kg^?1 respectively, were found in seedlings under pH 3.5 treatment. When Al and F concentrations in seedlings increased, elements such as Ca, Mg, Na and Zn gently decreased (p < 0.05) whereas P increased. K and Cu were not affected. The results indicated that soil pH values higher than 4 reduced Al and F concentrations in tea plants. © 2001 Society of Chemical Industry     

Determination of the exposure parameters that maximise the concentrations of the anaesthetic/sedative eugenol in rainbow trout (Oncorhynchus mykiss) skin-on fillet tissue

Studies were conducted to determine the anaesthetic/sedative concentrations and durations that would maximise anaesthetic/sedative residue concentrations in rainbow trout (Oncorhynchus mykiss) skin-on fillet tissue. Rainbow trout (167–404 g) were exposed to 50 mg l^?1 AQUI-S^® 20E (10% active ingredient, eugenol) in 17°C freshwater for durations up to 1440 min, 100 and 250 mg l^?1 AQUI-S^® 20E for durations up to 240 min, and 500 and 1000 mg l^?1 AQUI-S^® 20E for durations up to 90 min. Fish exposed to 100 mg l^?1 AQUI-S^® 20E for durations of 30, 60, 120 and 240 min had the greatest eugenol concentrations in the fillet tissue, 50, 58, 54 and 62 µg g^?1, respectively. All other exposure concentrations and durations resulted in significantly lower eugenol concentrations, i.e. all < 39 µg g^?1.     

Magnesium nutrition on accumulation and transport of amino acids in tea plants

BACKGROUND: Free amino acids in young tea shoots are important chemical constituents, remarkably influencing the quality of green teas. Nutrient solution, soil pot and field experiments were conducted to investigate the effect of magnesium nutritional status on accumulation and transport of free amino acids in tea plants ( Camellia sinensis (L.) O. Kuntze). RESULTS: A sufficient supply of Mg in nutrient solution increased biomass production and concentrations of free amino acids, notably theanine in young shoots and roots, without affecting total N in the leaves, absorption rates of inorganic N and glutamine synthetase activity. Amino acids in xylem saps and phloem exudates or total sugars in phloem exudates of tea plants from pot and field experiments showed their highest levels in bud breaking and shoot extension in early spring (March and early April). Application of Mg increased the amounts of amino acids and total sugars in the xylem saps and phloem exudates. CONCLUSION: Adequate supply of Mg nutrient promoted the synthesis of theanine in roots and its accumulation in the young shoots of tea plants. Magnesium nutritional status was an important factor influencing the mobility of amino acids and sugars via xylem and phloem especially when N and C reserves remobilized to support spring growth of young shoots. Copyright © 2011 Society of Chemical Industry     

Effects of Azadirachta excelsa on feeding behaviour,body weight and mortality of Crocidolomia binotalis Zeller (Lepidoptera: Pyralidae)

We investigated the effects of methanolic extracts of Azadirachta excelsa wood (SWE) at concentrations of 5, 10 and 20 g l^?1 against Crocidolomia binotalis. Second instars were fed a diet of cabbage leaves treated with SWE or were contacted topically with SWE. The results indicated that SWE produced significant (p < 0.05) antifeedant and contact toxicity effects. However, among the different treatments, a lesser effect on pupal weight was noted in the contact toxicity test. In most instances, untreated leaves were severely damaged, whereas leaves treated with SWE were not attacked or were only slightly damaged. Although both methods of SWE treatment caused a significantly high mortality rate, there was no difference in dose response in the range studied. Thus SWE at a concentration of 5 g l^?1 was shown to be as active as that at 20 g l^?1. The results indicate that SWE is a potent antifeedant and also has toxicity against C binotalis. Copyright © 2003 Society of Chemical Industry     

Toward a criterion for suspect thiouracil administration in animal husbandry

Thyreostats are growth-promoters banned in Europe since 1981. The identification of thiouracil (TU) in animal biological matrices can, however, no longer be systematically interpreted as a consequence of illegal administration. Indeed, some experimental results have indicated a causal link between cruciferous-based diet and the presence of TU in urine of bovines. The present study aims at investigating, on a large scale (n?>?1300), the natural occurrence of thiouracil in urine samples collected from different animal species. TU was identified in main breeding animal species: bovine, porcine and ovine. The natural distribution of TU allowed proposing threshold values to differentiate compliant from suspect urine samples. Suggested values are 5.7 and 9.1?µg?l^?1 in male adult bovines (6–24?months), 3.1 and 8.1?µg?l^?1 in female adult bovines (6–24 months), 7.3 and 17.7?µg?l^?1 in calves (<6 months), 3.9 and 8.8?µg?l^?1 in female bovines (>24 months), and 2.9 and 4.1?µg?l^?1 in porcines at a 95 and 99% confidence level, respectively.     

Investigation of the presence of prednisolone in bovine urine

Over the past two years low levels of prednisolone have been reported in bovine urine by a number of laboratories in European Union member states. Concentrations vary, but are reported to be below approximately 3 µg l^–1. Forty per cent of bovine urine samples from the Dutch national control plan had concentrations of prednisolone between 0.11 and 2.04 µg l^–1. In this study the mechanism of formation of prednisolone was investigated. In vitro conversion of cortisol by bacteria from faeces and soil, bovine liver enzymes and stability at elevated temperatures were studied. In vitro bovine liver S9 incubation experiments showed a significant 20% decrease of cortisol within 6 h, and formation of prednisolone was observed from 0.2 g l^–1 at t = 0 to 0.5 g l^–1 at t = 6. Under the influence of faeces, the stability of cortisol in urine is reduced and cortisol breaks down within 50 h. Prednisolone is formed up to 4 µg l^–1 at 70°C after 15 h. However, this decreases again to zero after 50 h. With soil bacteria, a slower decrease of cortisol was observed, but slightly higher overall formation of prednisolone, up to 7 µg l^–1 at 20°C. As opposed to incurred urine, in fortified urine incubated with faeces or soil bacteria no prednisolone was detected. This difference may be explained by the presence of natural corticosteroids in the incurred sample. With UPLC-QToF-MS experiments, in urine and water samples incubated with faeces, metabolites known from the literature could be (tentatively) identified as 20β-hydroxy-prednisolone, cortisol-21-sulfate, oxydianiline, tetrahydrocortisone-3-glucuronide and cortexolone, but for all compounds except 20β-hydroxy-prednisolone no standards were available for confirmation. Based on the results of this study and literature data, for regulatory purposes a threshold of 5 µg l^–1 for prednisolone in bovine urine is proposed. Findings of prednisolone in concentrations up to 5 µg l^–1 in bovine urine can, most likely, originate from other sources than illegal treatment with growth promoters.     

Ochratoxin A in wines,musts and grape juices from Spain

A survey on the occurrence of ochratoxin A (OTA) in 240 grape‐based beverages was carried out. Red and white wines from four different Spanish Designations of Origin (n = 160), musts (n = 20), grape juices (n = 10), ordinary wines (n = 20), special wines (Malaga, muscatel, sherry, vermouth, etc) (n = 20) and sparkling wines (n = 10) were assayed for OTA content using immunoaffinity column clean‐up and high‐performance liquid chromatography with fluorimetric detection (detection limit 0.05 µg l^?1). Forty‐three (17.9%) of the samples tested contained detectable levels of OTA. The overall mean OTA concentration in red and white wines of Designations of Origin was 0.30 and 0.18 µg l^?1 respectively (ranges 0.05–3.19 and 0.05–1.13 µg l^?1 respectively). The percentage of wine samples with detectable amounts of OTA was higher for red (18.3%) than for white (10%) wines. OTA was also found in two of 10 red ordinary wines (0.68 and 4.24 µg l^?1), whereas none of 10 white ordinary wines contained OTA. The mean OTA amount detected in sparkling wines was 0.44 µg l^?1 (range 0.14–0.71 µg l^?1). Two of 20 must samples contained OTA at low levels (0.08 and 0.18 µg l^?1), while none of 10 grape juice samples contained OTA. Highest amounts of OTA were found in special wines (45%), with a maximum of 15.25 µg l^?1 in a muscatel sample. Copyright © 2004 Society of Chemical Industry     

Uptake and distribution of iodine in grass and clover plants grown in solution culture

Perennial ryegrass (S23), timothy (S48), white clover (S100) and red clover (Hungaropoly), grown in culture solutions containing 0.2 × 10^?7, 1.0 × 10^?7, 5.0 × 10^?7 and 1.0 × 10^?6 M -potassium iodide, showed relatively small differences in iodine uptake. The lowest uptake occurred with timothy, the species that also produced the lowest yields of dry matter. Red clover had the lowest concentration of iodine in the shoots on all treatments, its difference from the other species being proportionately greater at the higher levels of iodide supply. The transport of iodine from roots to shoots was restricted in all species, with roots having much greater concentrations of iodine than shoots. However, with the exception of red clover, transport to the shoots increased considerably as the supply of iodide was increased. Two diploid and two tetraploid varieties of red clover also showed only small differences in uptake and concentration of iodine in their shoots and roots, although the tetraploid varieties did have somewhat lower concentrations in their shoots at the lowest level of iodide supply. Plants of perennial ryegrass and red clover grown for eight weeks on solutions containing 1.0 × 10^?7 M -iodide had higher concentrations of iodine in dead and senescent leaves than in green shoot material. Iodide was taken up much more readily than iodate, and chloride, even at concentrations up to 50000 times the iodide concentration, did not depress the uptake of iodide.     

Factors affecting the levels of catechins and caffeine in tea beverage: estimated daily intakes and antioxidant activity

Increased public awareness of health benefits of green tea is generally based on the high polyphenol content of tea leaves and the resulting beverage. A number of factors, such as species, season, agronomic condition and age of the leaves, are known to affect the composition of commercial teas. In the present study the effects of factors associated with domestic preparation and analytical methods, such as brewing time, concentration, solvent and type of tea product, on levels of catechins and caffeine, antioxidant activity and estimated daily intakes were investigated. There were large variations in the levels of total catechins: 43 and 117 mg g^?1 dry matter (DM) (brewed for 30 s and 5 min respectively); 72 and 161 mg g^?1 DM (extracted in boiling water and 50% acetonitrile respectively); 72 and 117 mg g^?1 DM (a tea bag and tea leaves respectively). The effects on caffeine content were comparatively smaller. These variations consequently led to considerable variations in estimated daily intakes based on three cups (600 ml), ranging between 538 and 2014 mg g^?1 DM of total catechins and between 103 and 466 mg g^?1 DM of caffeine. The antioxidant activity was highest (26 680 µmol g^?1 DM) for tea leaves brewed for 5 min and lowest (10 110 µmol g^?1 DM) for a tea bag product brewed for 1 min. Copyright © 2005 Society of Chemical Industry     

The phenolic profiles and antioxidant activity in different types of tea

Phenolics are suggested to be the major bioactive compounds responsible for the health benefits of tea. Seven types of tea were extracted using boiling water. The extraction kinetics was investigated. To more fully characterise the antioxidant profiles and possible associated health benefits of these tea types, the total water‐soluble solid content, phenolics, flavonoids, and antioxidant and antiproliferative activities were quantified. Green tea leaves (GTL) were found to have the highest phenolic content (128.7 ± 1.7 mg g^?1, P < 0.05), followed by teas of decaffeinated green tea bag (dGTB), green tea bag (GTB), black tea bag (BTB), decaffeinated BTB, black tea leaves and oolong tea leaves (OTL). Among the three leaf teas, GT displayed the greatest antioxidant activity (4850.2 ± 60.7 μmol g^?1, P < 0.05), followed by black tea (BT) and oolong tea (OT). As for the four bag teas, decaffeinated GT possessed the strongest antioxidant activity (4431.1 ± 335.0 μmol g^?1, P < 0.05), followed by GT, BT and decaffeinated BT. The results display that phenolic/flavonoid content well correlated with antioxidant activity. Proliferation of three human cancer cells was significantly inhibited in a dose‐dependent manner after exposure to some tea extracts. This may influence consumers in selecting the type of tea and tea brewing times, exhibiting greater health benefits.     

Fluoride content of soft drinks,nectars, juices,juice drinks,concentrates, teas and infusions marketed in Portugal

A potentiometric method using a fluoride combination ion-selective electrode was validated and used to analyse 183 samples, including soft drinks, juices, nectars, juice drinks, concentrates, teas and infusions marketed in Portugal. The fluoride levels were higher in extract-based soft drinks, juice drinks and juice, with fluoride values of 0.86 ± 0.35, 0.40 ± 0.24 and 0.37 ± 0.11 mg l^?1, respectively. The lowest fluoride concentration was found in infusion samples (0.12 ± 0.01 mg l^?1), followed by teas and carbonated soft drinks with fluoride concentrations of 0.16 ± 0.12 and 0.18 ± 0.07 mg l^?1, respectively. Nectars, concentrates and juice-based drinks had similar fluoride concentrations of 0.33 ± 0.16, 0.29 ± 0.12 and 0.25 ± 0.14 mg l^?1, respectively. The fluoride concentrations in all these samples would only contribute intakes below the acceptable daily intake (ADI = 0.05 mg kg^?1 body weight day^?1), indicating that, individually, these beverages cannot induce fluoride toxicity in the population group of children.     

Occurrence and stability of inorganic and organic arsenic species in wines,rice wines and beers from Central European market

We investigated in total 80 wine samples of different types and seven grape juice and 23 beer samples purchased from markets in Central Europe in order to understand the arsenic (As) speciation and help assess the potential As toxicity via intake of alcoholic beverages. Generally, total As concentrations in most samples investigated were below the drinking water limit 10?µg?l^?1 published by the World Health Organization (WHO); ranging from 0.46 to 21.0?µg?l^?1 As in red and white wines and from 0.75 to 13.4?µg?l^?1 As in beers. In addition, concentrations of total As in rice wine and in rice beer were 0.63–6.07 and 3.69–8.23?µg?l^?1 As, respectively. The total As concentrations in ice wine ranged from 7.94 to 18.8?µg?l^?1 As, significantly higher than in white and red wine. Arsenite predominated as the As species in most of the wine samples, whereas arsenate was the dominant species in rice wine, beer and rice beer. Methyl As components were usually minor components in all wine and beer samples. Monomethylarsonic acid, dimethylarsinic acid and two additional unknown As species were frequently found in grape juice, late harvest and ice wine with higher sweetness. After air exposure, arsenite, arsenate, monomethylarsonic acid and dimethylarsinic acid were stable at 4°C for months, probably due to the acidic conditions of wine and beer samples. The presence of sulfite had little influence on As speciation in wine. Despite the predominance of more toxic arsenite and arsenate in wine and beer, the estimated weekly exposure to As (via consumption of beer, wine and rice wine) is low. The As intake per capita is 6.81?µg from beer, <1.93?µg from wine and 0.88?µg from rice wine, estimated using the median of total As concentration multiplied by the average consumption per capita of the corresponding beverage.     

Dietary Intake of Fluoride in the United Kingdom and Fluoride Content of Some Foodstuffs

Using samples from the Total Diet Study, the average dietary intake per person of fluoride in the United Kingdom is estimated to be 1.82 mg day^?1. Beverages account for 71% of the total dietary intake and tea contributes most to the intake from the beverages group. Above-average consumption of tea, as recorded in Great Britain, could result in fluoride intakes as high as 8.9 mg day^?1. It is estimated that tap water containing 1 mg litre^?1 of fluoride could increase normal dietary intakes by 54%. Individual foods have been analysed and the results show that tea infusions and foods containing skin or bone have higher fluoride concentrations than other foods. Concentrations as high as 44 mg kg^?1 were found in the tail meat of krill, and a sample of mechanically deboned meat contained 2.8 mg kg^?1 fluoride. Samples of flour, bread, vegetables, meat and fish products and infant foods generally contained less than 1 mg kg^?1 of fluoride. Soft drinks from an area with a fluoridated water supply had a higher fluoride concentration than samples taken from an area with unfluoridated water.     

Occurrence of pyrrolizidine alkaloids in animal- and plant-derived food: results of a survey across Europe

Pyrrolizidine alkaloids (PAs) are secondary metabolites of plant families such as Asteraceae or Boraginaceae and are suspected to be genotoxic carcinogens. Recent investigations revealed their frequent occurrence in honey and particularly in tea. To obtain a comprehensive overview of the PA content in animal- and plant-derived food from the European market, and to provide a basis for future risk analysis, a total of 1105 samples were collected in 2014 and 2015. These comprised milk and milk products, eggs, meat and meat products, (herbal) teas, and (herbal) food supplements collected in supermarkets, retail shops, and via the internet. PAs were detected in a large proportion of plant-derived foods: 91% of the (herbal) teas and 60% of the food supplements contained at least one individual PA. All types of (herbal) teas investigated were found to contain PAs, with a mean concentration of 460 µg kg^?1 dry tea (corresponding to 6.13 µg L^?1 in [herbal] tea infusion). The highest mean concentrations were found in rooibos tea (599 µg kg^?1 dry tea, 7.99 µg L^?1 tea infusion) and the lowest in camomile tea (274 µg kg^?1 dry tea, 3.65 µg L^?1 tea infusion). Occurrence of PAs in food supplements was found to be highly variable, but in comparable ranges as for (herbal) tea. The highest concentrations were present in supplements containing plant material from known PA-producing plants. In contrast, only 2% of the animal-derived products, in particular 6% of milk samples and 1% of egg samples, contained PAs. Determined levels in milk were relatively low, ranged between 0.05 and 0.17 µg L^?1 and only trace amounts of 0.10–0.12 µg kg^?1 were found in eggs. No PAs were detected in the other animal-derived products.     

Optimisation of the Amido Black assay for determination of the protein content of grape juices and wines

While the heat/chill stability of white wines cannot be predicted from the total protein concentration, this information is useful in assessing the effectiveness of fining treatments. We have adapted the Amido Black assay for use in grape juice and wine. The response of bovine serum albumin (BSA) was similar in water, model wine and model juice. The linear range of the assay (<100 mg l^?1) extends beyond protein concentrations typically found in grape juices and wines. The limit of quantification was 11.1 mg l^?1 for BSA in model wine and 7.6 mg l^?1 in model juice, while the limit of detection was found to be less than 3 mg l^?1 in either solution. In contrast to other methods of protein determination, this assay is not affected by common wine phenolic and pectic compounds or by glutathione. The mean response of BSA was similar in model juice and red and white grape juices. The mean response of BSA in red wine was lower than in white wine and model wine (p < 0.001), and there was considerable variation in response among wines. Protein concentrations determined using this method were reproducible (CV < 10%). This optimised assay can be used to monitor protein levels in grape juices and wines. © 2001 Society of Chemical Industry