Caffeine in Chiang Rai tea infusions: Effects of tea variety,type, leaf form,and infusion conditions

Caffeine in Chiang Rai tea infusions was found to be dependent on infusion conditions (water temperature and infusion time), and leaf form (non-ground or ground) but independent of tea variety and type. For non-ground leaf samples, the higher the water temperature and the longer the infusion time, the higher the caffeine concentrations in tea infusions. After infusing for longer than 15 min, the dissolution rate of caffeine became slower and the concentration was essentially constant. For ground leaves, the caffeine content was not influenced by infusion time. Caffeine concentrations in tea infusions from Camellia sinensis var. sinensis (26.8 ± 0.81 and 22.3 ± 5.55 mg/100 ml for ground and non-ground samples, respectively) were not significantly different from that of Camellia sinensis var. assamica (24.4 ± 0.66 and 20.3 ± 5.07 mg/100 ml for ground and non-ground samples, respectively). The difference in caffeine concentration between green tea (28.1 ± 8.19 mg/100 ml) and oolong tea (20.3 ± 1.52 mg/100 ml) was not statistically significant.     

Heavy metal levels in two fish species Leuciscus cephalus and Lepomis gibbosus

The concentrations of heavy metals (Cd, Co, Cu, Fe, Mn, Ni, Pb, Zn) were measured in muscle, gill and liver of two fish species (Leuciscus cephalus and Lepomis gibbosus) caught from Saricay, South-West Anatolia. Levels of metals varied depending on different tissues in species. The mean concentrations (μg g⁻¹ wet weight) of heavy metals in tissues of Leucis cephalus were as follows: Cd: 0.010–0.084, Co: nd–0.131, Cu: 0.193–2.611, Fe: 4.240–172.000, Mn: 0.112–24.230, Pb: 0.068–0.874, Zn: 6.350–28.550, and in tissues of Lepomis gibbosus were as follows; Cd: 0.008–0.082, Co: nd–0.233, Cu: 0.065–4.360, Fe: 11.200–125.000, Mn: nd–12.434, Pb: 0.070–0.920, Zn: 6.540–16.064. Ni was not determined in all organs studied.     

Melatonin contents in mulberry (Morus spp.) leaves: Effects of sample preparation,cultivar, leaf age and tea processing

The effects of sample preparation, cultivar, leaf age and tea processing on melatonin content of mulberry (Morus spp.) leaves were investigated. Sample preparation using ultrasonic technique in combination with solid phase extraction resulted in high recovery rate (76%), when compared to homogenisation in combination with liquid–liquid extraction procedure (12% recovery rate). The melatonin contents in mulberry leaves harvested from three major cultivars (Buriram 60, Sakonnakhon and Khunphai) grown in Thailand were identified and quantified using high-performance liquid chromatography combined with fluorescence detector. The average melatonin content of the mulberry leaves cv. Buriram 60 (279.6 ng/g dry weight (DW)) was higher than those of cv. Sakonnakhon (100.5 ng/g DW) and cv. Khunphai (40.7 ng/g DW). The melatonin contents of all cultivars tested were highest in the tip of the leaves, followed by that in the young leaves, whereas the lowest was found in the old leaves. The melatonin contents of the two types of tea produced from mulberry leaves cv. Buriram 60 were also determined. Heat treatment during tea processing decreased the melatonin content in mulberry leaves cv. Buriram 60 by approximately 87%, when compared to that of the fresh leaves. However, there were no significant differences between the melatonin contents of the mulberry leaf tea produced with blanching (mulberry green tea) and those produced without blanching (mulberry black tea).     

Metal concentration of wild edible mushrooms in Soguksu National Park in Turkey

Twelve varieties of fruiting bodies of wild edible mushrooms collected in 2002 from Soguksu National Park, Ankara, Turkey were analysed for Pb, Cd, Zn, Fe, Mn, Cu, Cr, Ni, and Co contents by inductively coupled plasma optical emission spectrometry (ICP-OES). Dried samples were dissolved by microwave digestion. The contents of trace metals in the mushroom samples were found in the ranges: 0.7–4.2, 0.31–54.2, 29–146, 138–1714, 10–77, 6–187, not detected–21.6, 0.7–4.2 and not detected–5.2 mg kg⁻¹ for Pb, Cd, Zn, Fe, Mn, Cu, Cr, Ni and Co, respectively. The levels of Pb and Cd analysed in all edible mushroom samples except Agaricus arvensis and Ramaria obtusissima for Cd were found to be lower than the legal limits.     

Levels of nutritionally-important trace elements and macronutrients in edible leaves and grain of 27 nodulated cowpea (Vigna unguiculata L. Walp.) genotypes grown in the Upper West Region of Ghana

Analysis of edible leaves and grain of 27 nodulated cowpea genotypes in 2005 and 2006 revealed differences in mineral density. Cowpea genotype IT82D-889 exhibited high concentrations of P, K, Ca, Mg and S in grain relative to Brown Eye, IT84S-2246 and TVx3236. Fe concentration in cowpea grain ranged from 63 mg/kg in Ngonji to 137 mg/kg in Soronko, while Zn was 44 mg/kg in Ngonji and 65 mg/kg in Vuli-1. Leaf concentrations of Cu, Mn, B and Fe were consistently higher in the genotypes Apagbaala, IT84S-2246, Fahari and IT97K-499-39, while Fe, Cu, B and Zn were lower in TVu11424, Brown Eye, Vuli-1, Soronko and Glenda. Compared with spinach, cowpea leaves had greater levels of Fe (5-fold in magnitude), Mn, P, Ca, K and Mg. Based on these data it is likely that when and where the dietary intake of cowpea leaves is high in Africa, children would suffer less from micronutrient deficiency.     

Minor and trace elements in different honey types produced in Siena County (Italy)

The concentrations of 23 chemical elements (Al, As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Sb, Se, Sr, Th, Tl, U, Zn) were determined in 51 honey samples of different botanical origin produced in Siena County (Italy). K, Ca, Na and Mg were the most abundant elements, with mean contents of 1195, 257, 96.6 and 56.7 mg/kg, respectively. The Fe, Zn and Sr contents generally ranged from 1 to 5 mg/kg. Except for Ba, Cu, Mn and Ni, the trace element contents were below 100 μg/kg. The analytical data indicated a good level of quality of the honeys, especially with regard to the concentrations of toxic trace elements, such as As, Cd, Pb and Sb, and suggested a significant influence of the botanical origin on the element composition. Some local geological and geochemical features also seemed to affect the chemistry of the honey.     

Determination of metals in fish species from Aegean and Mediterranean seas

Determination of metal levels in muscles and livers of twelve fish species from Aegean Sea and Mediterranean Sea by ICP-AES was made. The levels of Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn in muscles of fish were <0.01–0.39, <0.01–0.45, 0.07–1.48, 0.51–7.05, 9.18–136, 0.18–2.78, 0.03–1.72, 0.21–1.28 and 3.51–53.5 mg kg⁻¹, respectively. Metal levels in muscles were generally lower than those in livers. Metal concentrations in the edible parts of fish were assessed for human uses according to provisional tolerable weekly intake (PTWI) and provisional tolerable daily intake (PTDI). The estimated values of all metals in muscles of fish in this study were below the established values. Therefore, it can be concluded that these metals in edible parts of the examined species should pose no health problems for consumers.     

Trace element levels in honeys from different regions of Turkey

A survey of 25 honey samples from different botanical origin, collected all over the Turkey was conducted to assess their trace element contents. The aim of this study was to determine the levels of cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn), copper (Cu), nickel (Ni), chromium (Cr), zinc (Zn), aluminium (Al) and selenium (Se) in honey samples from different regions of Turkey. Trace element contents were determined by a flame and graphite furnace atomic absorption spectrometry technique after dry-ashing, microwave digestion and wet-digestion. The accuracy of the method was corrected by the standard reference material, NIST-SRM 1515 Apple leaves. The contents of trace elements in honey samples were in the range of 0.23–2.41 μg g⁻¹, 0.32–4.56 μg g⁻¹, 1.1–12.7 μg g⁻¹, 1.8–10.2 μg g⁻¹, 8.4–105.8 μg kg⁻¹, 2.6–29.9 μg kg⁻¹, 2.4–37.9 μg kg⁻¹, 0.9–17.9 μg kg⁻¹, 83–325 μg kg⁻¹ and 38–113 μg kg⁻¹ for Cu, Mn, Zn, Fe, Pb, Ni, Cr, Cd, Al and Se, respectively. Iron was the most abundant element while cadmium was the lowest element in the Turkish honeys surveyed. The results showed that trace element concentrations in the honeys from different regions were generally correlated with the degree of trace element contamination of the environment.     

Elemental analysis of nuts and seeds by axially viewed ICP OES

A method for the multi-elemental determination of metals (Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Sr and Zn), metalloids (B and Si), and non-metals (Cl, P and S) in the babassu nut and mesocarp, sapucaia nut, coconut pulp, cupuassu pulp and seed, and cashew nut by axially viewed inductively coupled plasma optical emission spectrometry is presented. A diluted oxidant mixture (2 ml HNO₃ + 1 ml H₂O₂ + 3 ml H₂O) was used to achieve the complete decomposition of the organic matrix in a closed-vessel microwave oven. The accuracy of the entire proposed method was confirmed by standard reference material analysis (peach leaves-NIST SRM1547). The certified values showed a good agreement at a 95% confidence limit (Student’s t-test). The average RSD for repeatability of calibration solutions measurements were in the range of 1.1–6.7%. Limits of quantification (LOQ = 10 × LOD) were in the level of 0.00072–0.0532 mg/l. The macro and micronutrient ranges in the different nuts and seeds did not exceed the dietary reference intake (DRI), except for Mn in the babassu nut.     

Mineral composition of edible seaweed Porphyra vietnamensis

Edible seaweed Porphyra vietnamensis growing along seven different localities of the Central West Coast of India was analyzed for mineral composition (Na, K, Ca, Mg, B, Pb, Cr, Co, Fe, Zn, Mn, Hg, Cu, As, Ni, Cd and Mo) by inductively coupled plasma atomic emission spectroscopy (ICP-AES). The concentration ranges found for each sample, were as follows: Na, 24.5–65.6; K, 1.76–3.19, Ca, 1.40–6.12; Mg, 4.0–5.90 (mg/g d wt); Pb, 0.01–0.15; Cr, 0.13–0.22; Co, 0.06–0.20; Fe, 33.0–298; Zn, 0.93–3.27; Mn, 4.22–10.00; Hg, 0.01–0.04; Cu, 0.54–1.05; As, 1.24–1.83; Ni, 0.02–0.25; Cd, 0.14–0.55; Mo, 0.02–0.03 and B, 0.02–0.07 expressed in mg/100 g dry weight. Mineral composition of P. vietnamensis was found relatively higher as compared to the land vegetables as well as to other edible seaweeds, and it is in concurrence with the recent macrobiotic recommendation for western countries. It could therefore be used as food supplement as a spice to improve the nutritive value in the omnivorous diet.     

Analysis of Trace Metals and Perfluorinated Compounds in 43 Representative Tea Products from South China

Six trace metals (Cd, Pb, Cr, Cu, Zn, and Mn) and 2 perfluorinated compounds (PFCs), perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), were analyzed in 43 representative tea products (including 18 green, 12 Oolong, and 13 black teas) from 7 main tea production provinces in China, using the atomic absorption spectrophotometer for trace metals analysis and HPLC‐MS/MS for PFOS and PFOA analysis. The average contents of the 3 essential metals Mn, Cu, and Zn ions in the tea samples were 629.74, 17.75, and 37.38 mg/kg, whereas 3 toxic metals Cd, Cr, and Pb were 0.65, 1.02, and 1.92 mg/kg, respectively. The contents of heavy metals in the 3 types of tea were in the order of black tea > Oolong tea > green tea. Both PFOS and PFOA contents were low and PFOA content was higher than PFOS in the tea samples. The highest concentration of PFOA was 0.25 ng/g dry weight found in a Hunan green tea. The Principal component analysis was performed with the trace metals and PFCs to analyze the relationships of these indices. The results showed that black teas had higher trace metals and PFCs than green and Oolong teas, and the teas from Hunan and Zhejiang provinces had higher Pb and Cr than others.     

Fluoride in teas of different types and forms and the exposure of humans to fluoride with tea and diet

Human exposure to the fluoride (F) from commercial teas was assessed. The efficacy of the F leaching was determined from the total F (F_t) contents in the teas (53–435 mg/kg) and the F concentrations in tea infusions (0.31–3.55 mg/l of free F available to human organism). Both were determined with a fluoride ion selective electrode. The efficacies of F leaching from the green, oolong and black teas were 55–90% with continuous, and 74–100% by repeated infusions, and were not affected by the type or the manufactured form. Lower efficacies were observed from Pu’erh teas, 21–38% with continuous, and 37–59% by repeated infusions. The daily intake of F with daily consumption of five cups of tea can represent 9–101% of the adequate intake (AI) for an adult person with 70 kg, and with tea and diet 25–173% of the AI in non-fluoridated and 35–210% of AI in fluoridated areas. The upper limits of these intakes can be already associated with a risk of developing F-related adverse effects.     

The effect of recirculating aquaculture systems on the concentrations of heavy metals in culture water and tissues of Nile tilapia Oreochromis niloticus

To date, farming fish in recirculating aquaculture systems (RAS) is one of the most environmentally friendly ways of producing fish. However, with the trend towards intensification, and consequently decrease in water exchange rates, these systems may accumulate substances, such as heavy metals, in the water and fish. Inductively-coupled plasma-optical emission spectrometry (ICP-OES) and inductively coupled plasma-mass spectroscope (ICP-MS) were used to determine Al, As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn, in the water and fish (Nile tilapia Oreochromis niloticus). Three RAS were used, differing in daily water exchange rates (30, 70 and 1500 l/kg feed/d). The concentrations of As, Fe, Mn, Ni and Zn in the water increased with decreasing water exchange rates, suggesting an accumulation of heavy metals as more water was re-used. Such accumulation in the water was, however, not translated into accumulation in the liver and muscle. Accumulation of heavy metals was always higher in the liver than in the muscle; however, As reached 1.61 mg/kg wet weight in the muscle of fish farmed in RAS-70 l/kg feed/d. However, these levels are considerably lower than permissible safety levels for human consumption.     

Total phosphorus and its extractable form in plant drugs. Interrelation with selected micro- and macroelements

Determinations of total phosphorus, its extractable inorganic form and selected essential elements (Ca, Mg, Na, K, Fe, Zn, Mn, Cu) in 27 leaves of medicinal plants supplied from the Polish herbal enterprise – Herbapol, were carried out. After the microwave digestion of plant samples, the total phosphorus was determined spectrophotometrically, using the phosphomolybdenum blue method, whereas contents of metals were established by flame atomic absorption spectrometry (FAAS). Extraction with 2% (v/v) acetic acid solution was done in order to separate the extractable inorganic fraction of phosphorus, which was evaluated by the same method as used for the total elements. The macroelements (P, Ca, Mg, Na, K) were determined in a range of concentration from several hundreds of mg/kg to thousands of mg/kg of dry plant tissue. Microelements (Fe, Zn, Mn, Cu) were found in a range up to several hundreds of mg/kg of dry plant weight. The average level of the inorganic fraction of phosphorus represented 63.2% of the total concentration of that non-metal in leaves, which indicates that a large fraction of phosphorus may be bioavailable for people who often use herbal teas in their everyday diet. Statistically significant correlations between the total and extractable phosphorus and among metals (Ca–Mg, Ca–K, Ca–Fe, Mg–Fe, Cu–K, Cu–Zn, and Mn–Zn) were observed, confirming their indispensable role in activation of the same group of enzymes in medicinal plants. PCA revealed, that the levels of the total, extractable phosphorus and metals, may depend on the origin of the analyzed leaf sample from plants of the same plant species.     

Role of transition metals,Fe(II), Cr(II), Pb(II), and Cd(II) in lipid peroxidation

Cod liver oil was oxidized with Fenton-like systems containing transition metals Fe(II), Cr(II), Pb(II), and Cd(II). Malonaldehyde (MA) formed from 10 μl cod liver oil oxidized by a Fenton-like system containing each metal at levels of 0.25, 0.5, 1 and 4 μmol was analyzed by a gas chromatograph equipped with a nitrogen phosphorus detector. The MA production exhibited dose response and the greatest amount (837.0 ± 19.1 nmol) was obtained by the Fe(II) system at the level of l μmol. Generally, higher MA formation is observed in the lower the third ionization potential of the metal. The decreasing order of MA formed in the metal systems at the level of 1 μmol is Fe(II) > Cr(II)(274.1 ± 20.1 nmol) > Pb(II)(150.7 ± 13.0 nmol) > Cd(II)(95.4 ± 6.7 nmol). The amounts of MA formed in Cr(II), Pb(II), and Cd(II) systems were considerably lower than those in the Fe(II) system. The relative formations of MA in the Cr(II) and Pb(II) systems were similar to those in the Fe(II) system. The results suggest that trace amounts of metals contribute oxidative effects to lipid peroxidation followed by various diseases.     

Trace metals in raw cows’ milk and assessment of transfer to Comté cheese

As part of a program to assess the transfer of metals from soil to dairy products, the transfer of metal trace elements to milk and cheese was studied. Concentrations of non-essential (Cd and Pb) and essential elements (Cu and Zn) were determined by atomic absorption spectrometry in 61 samples of raw milk and 21 of the corresponding cheese. While metal concentrations (dry weight) in raw milk were very low (Cd: 0.34–1.01 ng/g; Pb: 0.009–0.126 μg/g; Cu: 0.28–1.71 μg/g; Zn: 20.62–30.96 μg/g), concentrations in the corresponding cheese were significantly higher (Cd: 0.68–11.37 ng/g; Pb: 0.020–0.925 μg/g; Cu: 5.35–21.34 μg/g; Zn: 33.66–63.41 μg/g). The retention factor R_t suggests a concentration effect during the cheese making process, especially in the case of Cu, due to the use of large copper vats. Concentrations of non-essential elements (Cd and Pb) in cheese largely remained below those considered as dangerous for consumers. Finally, Comté cheese may constitute a useful source of Cu and Zn in human diet.     

A survey of selected heavy metal concentrations in Wisconsin dairy feeds

Heavy metals such as zinc (Zn), copper (Cu), chromium (Cr), arsenic (As), cadmium (Cd), and lead (Pb) are potential bioaccumulative toxins of the dairy production system. The heavy metal content of dairy feeds, however, remains poorly documented, particularly in the United States. This survey determined the heavy metal content of 203 typical dairy ration components sampled from 54 dairy farms in Wisconsin. Lowest heavy metal concentrations were found in homegrown alfalfa (Medicago sativa L.) hay and haylage, and corn (Zea mays L.) grain and silage. Highest metal concentrations were found in purchased feeds, particularly mineral supplements, and to a lesser extent corn- or soybean-based concentrates. Zinc and Cu were found at the highest concentration in complete dairy (total mixed and aggregated component) rations and reflected the deliberate addition of these metals to meet animal nutrient requirements although more than half the farms fed Cu and Zn above US recommended levels. Concentrations of Cr, As, Cd, and Pb were present in much lower concentrations and decreased in the order Cr > As > Pb > Cd. No complete Wisconsin dairy ration contained heavy metal concentrations above US maximum acceptable concentrations and would be unlikely to induce any toxic effects in dairy cattle. Concentrations of Cd in complete dairy rations were closest to US maximum acceptable concentrations, suggesting the greatest potential long-term risk to exceed US maximum acceptable concentrations if whole farm levels of Cd were to increase in the future. With the exception of Pb, the main sources of Zn, Cu, Cr, As, and Cd in the complete dairy feed ration originated from imported feed. The continued importation of heavy metals in dairy feed is likely to be associated with accumulation of these metals in soils where manure is applied. Although the cycling of many heavy metals through the dairy food chain will be limited by factors such as a soil's cation exchange capacity, pH, salinity, and phytotoxicity of the metal, these may be less limiting for Cd. It is important that sources of Cd in the dairy system are identified and minimized to prevent problems associated with Cd accumulation in the dairy soil system arising over the long-term.     

Estimation of minerals,nitrate and nitrite contents of medicinal and aromatic plants used as spices,condiments and herbal tea

In this study, the minor and major mineral contents of 31 kinds of medicinal and aromatic plant collected from the south region of Turkey in 2004 year were established by inductively coupled plasma atomic emission spectrometry (ICP-AES). The samples were composed of Al, Ca, Fe, K, Mg, Na, P and Zn. The highest mineral concentration were measured between 57.70–2962.74 mg/kg Al, 1160.04–16452.88 mg/kg Ca, 44.83–1799.5 mg/kg Fe, 3570.73–27669.72 mg/kg K, 477.17–4313.59 mg/kg Mg, 1102.62–20912.33 mg/kg Na, 443.60–9367.80 mg/kg P and 7.18–48.36 mg/kg Zn. The highest values of Ca, K and P were established in Foeniculum vulgare (bitter fennel) (16452.88 mg/kg), Ocimum minumum (basil) (27669.72 mg/kg) and F. vulgare (bitter fennel) (9367.80 mg/kg), respectively. The heavy metal contents were determined too low in all samples.     

Elemental Composition of Various Sour Cherry and Table Grape Cultivars Using Inductively Coupled Plasma Atomic Emission Spectrometry Method (ICP-OES)

Three sour cherry and three table grape cultivars were analyzed using inductively coupled plasma optical emission spectrometry. The elements: Na, K, Ca, Mg, Fe, Cu, Zn, Mn, Cr, Cd, Co, Pb, and Ni were detected in all samples; four elements are very abundant (K, Na, Ca, and Mg), and four are not abundant (Cu, Fe, Mn, and Zn). Five of them are trace elements (Cr, Cd, Co, Pb, and Ni) at <0.1 mg/kg. Among the 13 elements analyzed, potassium was the most abundant element distributed throughout all categories of fruits. Iron was the predominant minor element constituents. Manganese concentration was the highest in table grape cultivars. The accuracy of the results was evaluated by spike recovery tests. Analysis of variance was used to establish the metals with significant difference in mean content between the cultivars from sour cherries and between table grapes. Principal component analysis was used to evaluate the distribution of metals.     

Determination of industrial pollution effects on citrus honeys with chemometric approach

The aim of this study was to determine the levels of essential, trace and toxic elements, such as K, Ca, Fe, Cu, Al, Ni, Sn, Pb and Cd in citrus honeys from different regions (industrialized and nonindustrialized) of Hatay, Turkey. K, Ca, Na and Mg were the most abundant elements, with mean contents of 363.5, 256.6, 88.1 and 37.7 mg/kg, respectively. The trace element mean contents ranged between 0.032 and 15.58 mg/kg. Significant differences in Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr levels were observed between two different regions. The findings that Fe, Cu, Al, Ni, Sn, Pb, Cd, Co and Sr contents in citrus honeys from industrialized regions were higher than citrus honeys from non-industrialized regions indicate that the honeys were affected by industrial pollution. Chemometric methods were applied to classify honey according to mineral content. Cluster analysis showed three clusters corresponding to the three different regions.