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1.
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  相似文献   

2.
茶绿色素稳定性的研究   总被引:1,自引:0,他引:1  
对茶绿色素的稳定性进行研究.结果表明:荼绿色素的光谱特性在663 nm为特征吸收峰;茶绿色素对热较稳定;金属离子K+、Na+、Zn2+、Cu2+、Mg2+,Ca2+对该色素的稳定性影响较小,Al3+、Fe2+和Fe3+对其稳定性有明显的影响或破坏作用;pH对该色素的影响明显,在弱酸性条件下(pH=5~6)稳定性较好;光对该色素的稳定性影响较大;苯甲酸钠对该色素的稳定性影响较小;该色素抗氧化性较弱,抗还原性较强.  相似文献   

3.
BACKGROUND: Tea is an infusion made from dried leaves of tea (Camellia sinensis) and can be a good dietary source of essential trace metals for humans. Therefore, it is necessary to consider variations in element content of tea leaves among tea cultivars. Thus, elemental fingerprint techniques, based on elemental contents (Al, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, P, Pb, and Zn) determined by inductively coupled plasma atomic emission spectrometry (ICP‐AES) and multivariate statistical analysis, have been used to differentiate eight tea cultivars. RESULTS: The ranges of element concentrations in leaves of the eight cultivars were in good agreement with those obtained in previous studies and the level of most elements in tea leaves was significantly different among cultivars. The classifications of eight tea cultivars were 100% accurate in total by principal component analysis (PCA), hierarchical cluster analysis (HCA), linear discriminant analysis (LDA), and back‐propagation neural network (BPNN) analysis. CONCLUSION: Each cultivar presented a distinctive element fingerprint and the elements in tea leaves can be significant predictors in differentiating tea cultivars. Copyright © 2009 Society of Chemical Industry  相似文献   

4.
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  相似文献   

5.
Five tea clones of the Camellia assamica variety grown in Wushwush tea plantation farms, Ethiopia, were analyzed for their contents of essential, non-essential and toxic metals (K, Ca, Mg, Fe, Mn, Cu, Zn, Na, Cd and Pb) by atomic absorption flame emission spectroscopy. Both the tea leaves and the soils of the study farms showed similar accumulation patterns in their contents of the studied macronutrients. Among the macronutrient metals, K was the most abundant element in the tea leaves (17.7–24.8 mg/g) and the soils (7.14–9.73 mg/g). Mn was the predominant micronutrient heavy metal in the tea leaf tissues ranging between 501 and 1281 mg/kg. Level of Fe (29.6–100 mg/kg) in the leaf tissue was found to be the second most abundant micronutrient next to Mn whereas concentrations of Cu and Co were relatively lower both in the soil and tea samples. The toxic heavy metals Pb and Cd in the leaf tissues were present at levels too low to be detected by the analytical technique used in this study. The soils were found to be acidic (pH 5.04–5.49) with high organic matter (5.48–6.02%). Fe was the most abundant metal followed by Mn, Na and Zn in the soils. Unlike the tea leaves, the soils were found to contain traces of the toxic metal, Cd (0.02–1.10 mg/kg). The levels of most of the metals determined in this study compared well with those reported for tea leaves from some other parts of the world.  相似文献   

6.
BACKGROUND: Turnip‐rooted parsley, a field‐crop of northern Europe, has recently been introduced to the Mediterranean region for fresh consumption or production of essential oil. Because of soil salinity within this area, the sensitivity of turnip‐rooted and two other parsley subspecies (plain‐ and curly‐leafed) to salt was studied. RESULTS: NaCl or CaCl2 additions to the irrigation water raised the electrical conductivity (EC) in increments from 0.5 dS m?1 to 4.5 dS m?1 (year 1) or 6.0 dS m?1 (year 2), reducing parsley foliage weight in year 2, but increasing the root weight of turnip‐rooted parsley in year 1. Raising the EC with NaCl increased the yield of foliar essential oil from curly‐leafed parsley (both years), but not from the other cultivars. CaCl2 had less effect on oil yield. The relative concentrations of the principal aroma constituents (β‐phellandrene, myristicin, β‐myrcene and apiole) of the foliar essential oil were affected by NaCl or CaCl2 in a way that differed between cultivars. Oil yield from parsley roots was very low and apparently unaffected by salinity. CONCLUSION: All three parsley subspecies are moderately sensitive to salinity, but may be cultivated at <4.5 dS m?1 EC. Salinity may assist oil production by increasing oil yield (curly‐leafed parsley) and positively affecting certain aroma constituents. Copyright © 2009 Society of Chemical Industry  相似文献   

7.
Contents of various elements in dyferent parts of the tea plant (shoot, mature leaf, small stem, thick wood and root), black tea manufactured by the crush-tear-curl and orthodox processes, and tea brew after 1 and 5 min of infusion were determined by inductively coupled plasma atomic emission spectrometry. From these, the amount of each element assimilated in the production of 1000 kg of marketable tea, as well as the quantity of each element brought into infusion and thus possib f y taken up through drinking tea, were calculated and discussed. Among the various elements assimilated by the tea plant, the shoot jraction (economically important for manufacturing commercial tea) contained high concentrations of N, P, K and Mg while the mature leaf accumulated Al, Bu, Ca, Cd, Mn, Pb and Sr. Of the dgerent elements brought into infusion while brewing black tea, the amount of K was found to be the largest (> 10000 μg g−1 tea) followed by P (700–1200 μg g−1), Mg (300–700 μg g−1), Ca and A1 (each 150–300 μg−1), Mn (60–150 μg g−1), Cu, Na, Si and Z n (each 6–50 μg g−1), B, Ba, Cr, Fe, Ni and Pb (each Id μg g−1), and Sr, Co and Gd (each <1μg g−1). The proportion of the totalamount of an element brought into infusion showed that the elements Ba, Ca, Fe and Sr were less soluble (<10 % of total amount), Al, B, Cd, Co, Cr, Cu, Mg, Mn, P, Pb, Si and Zn were moderately soluble (10–50 %), and K, Nu and Ni were highly soluble (>50%). The overall mean of the extent of solubility of all elements in 1 and 5 min showed that, out of the amount soluble in 5 min, about 68% was dissolved within 1 min.  相似文献   

8.
Abstract: Yellow‐cracking Bolete (Xerocomus subtomentosus) mushrooms and soil were collected from Note? Forest–a large forested enclave in western part of Poland. Mercury was determined by cold vapour atomic absorption spectroscopy and the other elements by inductively coupled plasma atomic emission spectroscopy. K, P, and Mg were particularly abundant, with mean values of 46000, 8400, and 1100 mg/kg dry weight (dw) in caps followed by Na, Rb, Zn, and Ca with mean concentrations of 580, 350, 200, and 170 mg/kg dw, respectively. In descending order, the mean concentrations of Fe, Al, Cu, and Mn were 52, 49, 46, and 14 mg/kg dw, while the mean for the remaining elements was around 1.0 mg/kg dw or less. The elements such as Ca, Cu, Hg, K, Mg, Na, P, Rb, Zn, Ag, Cd, and Ni were accumulated (with bioconcentration factor (BCF) > 1), while Al, Ba, Fe, Mn, Sr, Co, Cr, and Pb were excluded (BCF < 1) in the fruiting bodies. The Pb and Cd content did not exceed the maximum levels set by the EU for cultivated mushrooms. Mercury in a conventional meal (300 g) portion of Yellow‐cracking Bolete was far below the provisionally tolerable weekly intake of 0.004 mg/kg body weight (bw) as reevaluated recently by WHO. Practical Application: The method presented in this study allows one to determine the content of 20 elements (Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, Rb, Sr, and Zn) in caps and stipes of Yellow‐cracking Bolete (Xerocomus subtomentosus) mushrooms and soil samples collected from Poland. This study has revealed that the total Cd, Hg, and Pb dose provided to human body due to consumption of Yellow‐cracking Bolete does not pose threat to a consumer's health.  相似文献   

9.
Abstract The mineral composition of medlar fruit collected (June 15 - October 8) in Turkey at five stages of development was studied. In the fruit, 32 minerals were analyzed and 16 minerals (Al, Ba, Ca, Cu, Co, Fe, K, Li, Mg, Mn, Na, Ni, P, Sr, Ti and Zn) were present at detectable levels. The ripe medlar fruit was richest in potassium (7370 μg/g dry wt), calcium (1780 μg/g dry wt), phosphorus (1080 μg/g dry wt), magnesium (661 μg/g dry wt) and sodium (183 μg/g dry wt). During the fruit development, Al, Ba, Fe, Mn, P, Sr, and Zn were highest in August (unripe fruits) while the concentrations of K, Ca, Mg and Cu gradually decreased throughout development. The ripe medlar fruit is an important source of nutritionally needed minerals and trace elements, in particular Ca, Cu, Fe, K, Mg, Mn, Na and Zn, for human populations in southeastern Europe, Turkey and Iran.  相似文献   

10.
Concentrations of eight essential minerals were determined in 78 samples of goats'milk from the Canary Islands. The following mean values (ranges) were found: Se (μ/L), 19.98 (9.2‐31.2); Fe (mg/L), 0.52 (0.19‐1.17); Cu (mg/L), 0.17 (0.08‐0.31); Zn (mg/L), 3.31 (1.6‐4.6); Na (mg/L), 514 (289‐906); K (mg/L), 1585 (1212‐2160); Ca (mg/L), 1533 (1118‐1962); and Mg (mg/L), 157 (101‐210). Comparing with data for human milk and cows' milk from the Canary Islands, the mean concentrations of Se, K and Mg arranged in according the following sequence: goats' milk > cows' milk > human milk. Cows' milk had the highest (P<0.05) mean concentration for Ca and Zn, while humans had the highest (P < 0.05) mean concentration for Cu. The milk of goats milked once per day had significantly higher concentrations of Se and lower Mg and Zn than the milk of goats milked twice per day. While the concentrations of Na and Mg increased significantly from March to August, the concentrations of Se, Fe and Cu in goats' milk decreased significantly from March to June.  相似文献   

11.
The current study describes a fast and efficient procedure of ultrasound-assisted extraction for determination of Ca, Mg, K, Na, Cu, Zn, Mn, and Al in tea leaves by inductively coupled plasma optical emission spectrometry (ICP OES). The variables of procedure were optimized using the Box–Behnken design and the conditions selected were nitric acid concentration (1.0 mol L?1), sonication time (7 min), and sonication temperature (75 °C). The extraction efficiency was calculated using the analyte concentration obtained by a total digestion procedure as reference. Accuracy was confirmed by analysis of certified reference material of apple leaves (NIST 1515) and spinach leaves (NIST 1570a) using the procedure proposed. A statistical evaluation using Student’s t test showed that there is no significant difference between the value obtained with the proposed procedure and the certified value, at 95% confidence level. The proposed procedure was successfully applied and is a good alternative to conventional acid digestion procedure and can be applied to routine analysis for determination of Ca, Mg, K, Na, Zn, Mn, Cu, and Al in tea leaves used for the preparation of infusions.  相似文献   

12.
《Food chemistry》2002,76(4):483-489
The metal content of several tea beverages, infusions, instant and tea soft drinks was determined. Eleven metals Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, Sr and Zn were determined by inductively coupled plasma atomic emission spectrometry (ICP–AES). A study of the differences in the metal contents of tea beverages has been carried out. Pattern recognition techniques such as principal components analysis and linear discriminant analysis were used to discriminate between the tea beverages. The metal intake related to tea consumption has also been studied.  相似文献   

13.
以张掖高台种植的文冠果芽茶与叶茶为试验材料,对其营养功能成分及抗氧化活性进行比较;使用INQ法对其营养成分进行质量评价,并对功能成分与抗氧化能力进行相关性分析。结果表明,芽茶中K、Zn、Cu含量及K/Na显著高于叶茶(P<0.05),二者均呈现高K低Na特点。芽茶中粗蛋白含量显著高于叶茶(P<0.05)、而粗脂肪含量叶茶显著高于芽茶(P<0.05)。营养质量评价表明,芽茶、叶茶K、Ca、Fe、Mn、Zn、Cu、粗脂肪、粗蛋白INQ均>1;Na、Mg和可溶性总糖INQ芽茶<叶茶<1。芽茶多酚含量显著高于叶茶(P<0.05),黄酮含量差异不明显。芽茶与叶茶对DPPH自由基、ABTS自由基、O2?·清除能力的IC50分别为2.52和2.69、1.65和1.74、1.64和2.10 μg·mL?1,阳性对照芦丁在此浓度范围内无IC50,抗氧化能力强弱为芽茶>叶茶>芦丁。相关性分析表明,芽茶、叶茶多酚、黄酮含量与DPPH自由基、ABTS自由基、O2?·清除率均呈极显著正相关(P<0.01),芽茶相关系数为0.892~0.990,叶茶相关系数为0.879~0.994。以上研究表明,文冠果芽茶的营养功能价值及抗氧化能力优于叶茶,有开发新产品的潜力。  相似文献   

14.
用微波消解,电感耦合等离子体发射光谱法测定小米和高粱米中的金属元素。试验结果表明,2种粗粮中富含多种对人体有益的K,Na、Ca、Mg、Al、Fe、Zn、Cu等金属元素。对比发现,高粱米中各种金属元素的含量远远超过大米,8种金属元素的含量均是大米的几十至几百倍;小米中的各种金属元素的含量也超过大米。可见小米和高粱米是人们饮食中很好的矿物质来源。方法回收率在92.0%~102.0%之间,相对标准偏差小于4.8%。方法操作简单,分析速度快,准确度高,灵敏度好。  相似文献   

15.
Concentrations of K, Na, Fe, Zn, Ca, Cu and Mg were determined in the longissimus dorsi, semimembranosus and diaphragm muscles. In 94 market weight animals the average concentrations of the elements in ppm of wet weight in the three muscles ranged as follows: Cu, 0.70–1.66; Fe, 18.0–38.1; Ca, 23.8–30.2; Zn, 26.8–40.5: Ma. 198–248: Na. 528–708: and K. 3060–3840. The concentrations of all seven elements in the diaphragm muscle were significantly different from those in the other two muscles. The Cu, Fe, Zn and Mg contents in the longissimus dorsi were significantly different from those in the semimembranosis. Sex and breed differences were less pronounced. In a group of 20 mature cows, Fe, Ca, Zn, Mg and Na were affected by age.  相似文献   

16.
The elemental concentration of K, Na, P, Ca, Fe, Mg, Cu, Zn, and Mn was determined in seeds of three cultivars of cowpeas [Vigna unguiculata (L.) Walp.] treated with 0, 2000, and 4000 ppm simazine as a foliar spray and side dressed with 0, 30, and 60 kg/ha ammonium nitrate fertilizer. The element Ca was increased by the simazine treatment in‘Pinkeye Purple Hull’and Mn was increased by the ammonium nitrate fertilizer treatment in‘Mississippi Silver’. Significant fertilizer by simazine interactions were found with the remaining elements. Similar treatment responses in the elemental concentration were found among the three cultivars. The percentage recommended dietary allowances based on the individual elemental concentrations that a 100s raw edible portion of cowpeas would supply were not significantly affected by the treatments.  相似文献   

17.
加工精度对大米矿物元素指纹信息影响研究   总被引:1,自引:0,他引:1  
矿物元素指纹分析技术已逐渐被应用到农产品的产地溯源中,大米中的矿质元素指纹信息的稳定性不仅与环境(地域和年际)密切相关,还受品种和加工精度的影响。研究农产品矿物元素指纹信息在不同加工等级与不同品种间的稳定性,解析品种、加工精度及其交互作用对各元素含量变异的贡献率,筛选出受品种、加工精度影响较小的元素作为产地溯源的指纹信息。可为农产品产地矿物元素指纹溯源技术的应用提供理论参考。本研究以水稻作为模式生物,于2013年收获期在黑龙江同一地市的3个品种的水稻样品,加工成5个不同等级,利用电感耦合等离子体质谱仪(ICP-MS)测定不同等级大米中49种矿物元素的含量。对数据进行单因素方差分析、多因素方差分析。大米中元素Na、Mg、Al、K、Ca、Cr、Mn、Fe、Co、Cu、Zn、Rb、Sr和Ba含量与加工精度密切相关;元素Na、Mg、Al、K、Ca、Cr、Mn、Cu、Zn、Rb和Mo含量与品种密切相关;在今后产地溯源技术筛选溯源指标时应考虑这些元素。  相似文献   

18.
The quantitative analysis of Al, B, Cu, Fe, Mn, P and Zn by inductively coupled plasma optical emission spectrometry (ICP-OES) and Ca, K and Mg by atomic absorption spectrometry (AAS) has been carried out in both the raw material and infusions from 31 samples of traditional plant stimulants (tea and coffee) and mate, rooibos, honeybush and chamomile. The results were discussed with respect to differences to the beverage quality and their role in the human diet. The levels of elements not significantly differ between tea types (black, green, oolong, white), and between Arabica and Robusta coffee. In comparison with tea, coffee was found to be a poor source of elements with the exception of Ca and Fe. High levels of B, Ca, Cu, Mn, Mg and Zn were found in mate (mainly green type) and of B, Ca, Cu, Fe and P in chamomile, whereas the amounts of all elements in rooibos and honeybush infusions were low (except of Ca). Apart from tea, other stimulants appeared to not represent important sources of potentially harmful amounts of Al for the human diet.  相似文献   

19.
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.  相似文献   

20.
《Journal of dairy science》2022,105(3):2315-2325
This observational study described first-milking colostrum mineral concentrations and total yields, and evaluated its associations with cow serum mineral concentrations, parity, and first postpartum milking yield in 100 multiparous Jersey cows from a single herd fed a negative dietary cation-anion difference diet prepartum. Additionally, first- and second-milking colostrum mineral concentrations and total yields were compared in a subset of 65 cows. Serum minerals (Ca, P, Mg, Na, K, Zn, Fe, Cu) were assessed before first milking. Cows were milked at 9 h and 4 min ± 3 h and 32 min and at 21 h and 11 min ± 3 h and 43 min postpartum (± standard deviation); yields were recorded and samples collected for mineral concentrations assessment (Ca, P, Mg, Na, K, Zn, Fe, Cu). Linear regression was used to evaluate the associations between first-milking colostrum mineral concentrations and total yields and cows' serum mineral concentrations, parity, first-milking colostrum yield, and calving-to-milking interval. The most abundant minerals in first-milking colostrum were (least squares mean ± standard error of the mean) Ca (55.71 ± 13.52 mmol/L; 8.75 ± 5.74 g) and P (41.91 ± 13.01 mmol/L; 5.26 ± 3.72 g), followed by Na (39.65 ± 13.23 mmol/L; 3.08 ± 1.77 g), K (36.47 ± 7.57 mmol/L; 5.79 ± 4.20 g), Mg (13.43 ± 3.09 mmol/L; 1.25 ± 0.78 g), Zn (272.12 ± 113.34 μmol/L; 71.98 ± 55.34 mg), Fe (12.51 ± 3.79 μmol/L; 2.56 ± 1.55 mg), and Cu (3.34 ± 1.22 μmol/L; 0.77 ± 0.56 mg). Higher concentrations of Ca, Mg, Na, Zn, Fe, and Cu, and total yields of Mg, Zn, Fe, and Cu were observed at first- compared with second-milking colostrum. Serum and first-milking colostrum Cu concentrations were positively associated, but no significant associations were observed between other minerals' serum and first-milking colostrum concentrations or total yields. Parity was associated with first-milking colostrum Ca, P, K, and Fe concentrations and yields; younger multiparous cows had higher concentrations and total yields of these minerals. Linear (Fe), quadratic (P, Na, and K), and cubic (Mg, Zn, and Cu) associations were observed between first-milking colostrum mineral concentrations and yield. In all cases, mineral total yields were linearly associated with first-milking colostrum yield. In conclusion, variation in first-milking colostrum mineral concentrations and total yields across cows could be partially explained by cow parity and colostrum yield. Further research including primiparous and cows under different management settings is needed to expand the knowledge and understanding of colostrum mineral concentrations and total yields in dairy cows.  相似文献   

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