清香型乌龙茶品质形成中游离氨基酸指纹图谱变化规律

为探明游离氨基酸在茶树新梢生育过程的代谢变化及清香型乌龙茶制作工艺对其指纹图谱化学模式的影响,分别以铁观音、黄棪、金观音和黄观音品种春茶新梢为供试材料,对其新梢生育及乌龙茶制作过程中的游离氨基酸进行高效液相色谱-AQC(6-氨基喹啉基-N-羟基琥珀酰亚氨基甲酸酯)柱前衍生化检测分析。结果表明,18种已标定游离氨基酸指纹峰面积经标准化(尤其是自然对数变换)数据预处理后,再进行相似度分析(夹角余弦)、聚类分析法(欧氏距离-近邻法)和主成分分析,均可获得较为一致的可视化模式识别结果。4个茶树品种可划分为铁观音和黄棪、金观音和黄观音2个类群,不同生育期芽叶与清香型乌龙茶在制品可进行较好区分。茶氨酸、甘氨酸、谷氨酸等8种主要游离氨基酸在茶树新梢生育过程中发生较为明显的增减变化,且在中、小开面2～4叶中的含量相对较低;在清香型乌龙茶制作过程中,各主要游离氨基酸含量发生小幅变化,毛茶成品中略有增加。由此可见,游离氨基酸在茶树新梢生育过程中含量及组成的动态变化较清香型乌龙茶制作工艺的影响更为明显。该研究结果可为清香型乌龙茶鲜叶原料选取和品质工艺控制提供参考。     

不同品种乌龙茶种植后土壤肥力和茶叶品质的变化

本研究以毛蟹(C.sinensis cv.Maoxie)、本山(C.sinensis cv.Benshan)、梅占(C.sinensis cv.Meizhan)3个乌龙茶品种为研究对象,分析不施肥条件下茶树根部土壤养分随种植年限的变化,以及茶叶品质的变化。结果表明,不同茶树的根部土壤p H值均随茶树种植年限的增长而呈现下降趋势。不同茶树根部土壤的有机质及有效磷含量达到Ⅰ级肥力;0年取样的茶树土壤碱解氮含量为Ⅰ级肥力,不施肥种植1~2年后均为Ⅱ级肥力;土壤速效钾含量在茶树0年取样时为Ⅰ级肥力,不施肥种植1年后毛蟹根部土壤为Ⅲ级肥力,本山和梅占则为Ⅱ级肥力,2年后均为Ⅲ级肥力。茶树叶片品质分析结果表明,随着不施肥种植时间的延长,茶叶中茶多酚、茶氨酸、咖啡碱的含量呈现下降趋势。同一种茶树在不同种植年限间,茶多酚含量的变化较为微弱,而茶氨酸、咖啡碱含量则呈显著差异。不同种植年限下茶树叶片中表没食子儿茶素没食子酸酯、表儿茶素没食子酸酯与表没食子儿茶素含量及其品质指数均随着不施肥种植时间的延长而呈下降趋势,且同一种茶树不同种植年限间的变化率均呈显著差异。     

Near-infrared spectroscopy in saffron quality control: determination of chemical composition and geographical origin

Near-infrared reflectance spectroscopy has been applied for the first time to saffron spice to determine the chemical composition and geographical origin of 111 samples from the there main producers' countries: Iran, Greece, and Spain. The validation procedures with the results obtained by UV-vis and HPLC-DAD measurements demonstrated that this technique is appropriate to determine the following parameters: moisture and volatile content, coloring strength, (250 nm), and (330 nm), established on the ISO 3632 Technical Specification Normative and used to certify saffron quality in the international market. Also, it can be used to estimate the content of the five main crocetin glycosides, the compounds responsible for saffron color, the best correlations being for trans-crocetin di-(beta-D-gentibiosyl) ester (R2= 0.93), trans-crocetin (beta-D-glucosyl)-(beta-D-gentibiosyl) (R2= 0.94), and picrocrocin (R2= 0.92), the compound accepted as responsible for saffron bitterness. Finally, a discriminant analysis among the three geographical origins reveals that Iranian samples are the most different, whereas Greek and Spanish samples are more similar. All of these results reveal that NIRS spectroscopy has an enormous potential for its application to saffron quality control as the results are obtained in 2 min and without any sample manipulation.     

Total polyphenol content and antioxidant capacity of commercially available tea (Camellia sinensis) in Argentina

Tea, Camellia sinensis (L.) O. Kuntze (Theaceae) is cultivated in Argentina in the northeastern region (provinces of Misiones and Corrientes), between 26 degrees and 28 degrees south latitude, the southernmost area of the world where tea is cultivated. The objective of this work was to determine the total polyphenol content and the in vitro antioxidant capacity of green and black tea cultivated and industrialized in Argentina. Twelve samples of eight brands were analyzed. The total polyphenol content was determined according to the International Organization for Standardization method (ISO) 14502-1 for the determination of substances characteristic of green and black tea. The antioxidant capacity was determined by the ferric thiocyanate method (FTC) and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) free-radical scavenging assay. Green tea showed a higher polyphenol content than black tea. The total polyphenol concentration in green tea was found to vary from 21.02 +/- 1.54 to 14.32 +/- 0.45% of gallic acid equivalents (GAE), whereas in black tea, the polyphenol content ranged from 17.62 +/- 0.42 to 8.42 +/- 0.55% of GAE (P < 0.05). A similar profile was observed for the antioxidant capacity determined by both methods. The antioxidant activities were well correlated with the total polyphenol content (r (2) = 0.9935 for the ferric thiocyanate method and r (2) = 0.9141 for the 1,1-diphenyl-2-picrylhydrazyl free-radical scavenging assay). This is the first systematic screening for the quantification of polyphenols and antioxidant activity in tea commercialized in Argentine markets. The results obtained herein allow one to conclude that Argentine tea is of very good quality when compared to teas from other sources.     

Pigments in green tea leaves (Camellia sinensis) suppress transformation of the aryl hydrocarbon receptor induced by dioxin

Environmental contaminants such as dioxins enter the body mainly through diet and cause various toxicities through transformation of the aryl hydrocarbon receptor (AhR). We previously reported that certain natural flavonoids at the dietary level suppress the AhR transformation induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In this study, we identified lutein and chlorophyll a and b from green tea leaves as the novel antagonists for AhR. These active compounds suppressed AhR transformation dose-dependently with the 50% inhibitory concentration (IC(50)) values against 0.1 nM TCDD-induced AhR transformation at 3.2, 5.0, and 5.9 microM, respectively. (-)-Epigallocatechin gallate, which is the most abundant flavonoid in green tea leaves, also showed stronger suppressive effects than did other major tea components, with the IC(50) value of 1.7 microM. Thus, these pigments of green tea leaves have the potential to protect from dioxin toxicity through the suppression of AhR transformation.     

Determination of tea polyphenols and caffeine in tea flowers (Camellia sinensis) and their hydroxyl radical scavenging and nitric oxide suppressing effects

The native occurrence of tea polyphenols, namely, (-)-epicatechin, (+)-catechin, (-)-epigallocatechin 3-gallate, (-)-epicatechin, and (-)-epicatechin 3-gallate, and caffeine in tea flowers was assessed by an isocratic HPLC procedure. The levels of total catechins and caffeine were determined in tea flowers collected from 10 different species of Camellia sinensis. The results showed the levels of total catechin ranged from 10 to 38 mg/g, whereas the level of caffeine ranged from 3 to 8 mg/g. Levels of catechins and caffeine in tea leaves and various teas were also determined and ranged from 2 to 126 mg/g and from 23 to 49 mg/g, respectively. Both tea flower and tea leaf extracts exert their strong hydroxyl radical scavenging effects in the Fenton reaction system and nitric oxide suppressing effects in LPS-induced RAW 264.7 cells. Most tea flowers contain less caffeine, but comparable amounts of total catechins, compared to tea leaves and teas. The present study demonstrates that both tea flowers and tea leaves contain appreciable amounts of catechins and caffeine. It is likely that tea flowers might be useful for making alternative tea beverages.     

Sensory quality and chemical composition in carrots: A multivariate study

Carrots from designed trials and organic and conventional farms were analysed for sensory quality and chemical composition. The data were combined in principal component analyses and partial least squares regression for exploration of the main factors responsible for the variation in quality. One of the most important factors was fertilization. Carrots grown with no fertilizer and carrots fertilized with 40–80 kg nitrogen ha^?1 as mineral fertilizer or 20–72 tons ha^?1of organic fertilizer contained more total sugars and total flavour strength, less crispness, crude protein, true protein and carotene, and had a lower pH, compared with carrots fertilized with 100–192 kg nitrogen ha^?1 as mineral fertilizer. Location site was also very important in the explanation of the total variation and was a composite factor of precipitation, temperature in June, growth system and length of growth period. Soil type, amount of organic fertilizer, use of pesticides and temperatures in July and August seemed to be of less importance.     

Uptake,transport and assimilation of 15N-nitrate and 15N-ammonium in tea (Camellia sinensis L.) plants

¹⁵N studies were conducted using hydroponically grown tea (Camellia sinensis L.) plants to clarify the characteristics of uptake, transport and assimilation of nitrate and ammonium. From the culture solution containing 50 mg L^-1 N0₃-N and 50 mg L^-1 NH.-N, the uptake of NH₃-N after 24 h was twice as high as that of NO₃-N, while the uptake of N0₃-N from the culture solution containing 90 mg N0₃-N and 10 mg NH₃-N was twice that of NH₄-N. The presence of 0.4 mM Al had no significant effect on the N0₃-N and NH₄-N uptake from the culture solutions containing 50 mg L^-1 N0₃-N and 50 mg L^-1 NH₄-N, 90 mg L^-1 N0₃-N and 10 mg L^-1 NH₄-N or 99 mg L^-1 N0₃-N and 1 mg L^-1 NH₄-N. Transport of N0₃-derived N to young leaves was much more rapid than that of NH₄-derived NO₃ and NH₄-derived N was largely retained in the roots and lower stem. Young and mature shoots separated from the roots absorbed more N0₃-N than intact plants. Nitrate assimilation occurred in both, roots and young as well as mature leaves. Internal cycling of N0₃-derived Nand NH₄-derived N from one root part to another part was not appreciable after 28 h, suggesting that a longer of time is required for cycling in woody plants.     

对比不同微生物肥料与化肥对茶园土壤肥力和茶叶品质的影响

为探究微生物肥料对茶园土壤肥力及茶叶产量与品质的影响,以茶树“龙井43”品种为材料,通过田间试验,研究了不施肥(CK)、常规化肥(TF)、多菌种复合微生物肥料(BCF1)、豆粕发酵类微生物肥料(BCF2)、黄腐酸类微生物肥料(BCF3)对茶园土壤养分含量与碳、氮、磷转化酶活性及绿茶产量与品质的影响。结果表明,与常规化肥相比,3种微生物肥料使土壤pH平均提升0.27个单位、容重显著降低9.73%,土壤速效钾、有效磷、有机质和碱解氮含量平均提升9.72%、6.25%、9.19%和5.40%;与常规化肥相比,3种微生物肥料使土壤β-葡萄糖苷酶、β-N-乙酰氨基葡萄糖酶活性分别增加11.61%、20.13%,且黄腐酸类微生物肥料使亮氨酸氨基肽酶、纤维二糖苷酶和β-木聚糖酶活性分别显著增加97.70%、66.44%和71.62%。与常规化肥相比,3种微生物肥料处理使茶叶磷积累量上升10.08%;铁、钙、锰和镍分别增加19.63%、7.56%、12.06%和24.14%。与常规化肥相比,黄腐酸类微生物肥料显著提高了百芽重、发芽密度、鲜叶产量和游离氨基酸总量。相关性分析表明鲜叶产量与土壤速效钾、碱解氮、有机质含量及纤维二糖苷酶、酸性磷酸酶和β-木聚糖酶活性显著正相关(P<0.05)。综上所述,3种微生物肥料相比化肥可以更好地提高茶园土壤肥力,提高茶叶产量和品质,其中黄腐酸类微生物肥料效果最好。     

Enhancement in growth and quality parameters of tea [Camellia sinensis (L.) O. Kuntze] through inoculation with arbuscular mycorrhizal fungi in an acid soil

The present study was undertaken to determine the effect of inoculation with arbuscular mycorrhizal fungi (AMF) from natural and cultivated tea rhizospheres (NTR and CTR, respectively) on growth as well as on quality parameters of tea [Camellia sinensis (L.) O. Kuntze]. Seeds (after germination) and cuttings were inoculated with AMF consortia from NTR and CTR in non-sterilized acid soil (pH 5.0). Seedlings and cuttings were grown under net-house conditions and the data on growth and quality parameters were recorded up to 2 years. Tea plants were found to be highly colonized by AMF (74–83%) after 1 year. The significant increase in most of the growth parameters (root/shoot length, dry weight; r/s ratio) was recorded in AMF-treated plants, which also showed better tea quality parameters than noninoculated plants. Maximum significant increases up to 31% and 100%, over control, were recorded in amino acids and total protein content, respectively. Similarly, maximum increase in total polyphenols (15%) and caffeine content (34%) over control was also significant. Enhanced sugar content (maximum 16% in total soluble sugars, maximum 45% in reducing sugars, and maximum 69% in non-reducing sugars) was recorded in AMF-inoculated plants. In most cases, better response was observed in tea plants inoculated with AMF consortia from NTR. These results indicate that growth and quality of tea can be improved by AMF inoculations in acid soils.     

Phosphate rock dissolution and transformation in the rhizosphere of tea (Camellia sinensis L.) compared with other plant species

Tea (Camellia sinensis L.) is generally grown in highly weathered acidic Ultisols of the humid tropics. The low pH, large P fixing capacity and moisture content of these soils favour the dissolution of phosphate rock. Plant species differ widely in their ability to take up P from phosphate rock, and we have compared phosphate mobilization in the rhizosphere of tea with that under calliandra (Calliandra calothyrsus L.), Guinea grass (Panicum maximum L.) and bean (Phaseolus vulgaris L.) by studying the changes in the concentration of P fractions at known distances from the root surface in an acidic (pH in water 4.5) Ultisol from Sri Lanka treated with a phosphate rock. Plants were grown in the top compartment of a two-compartment device, comprising two PVC cylinders physically separated by a 24-μm pore-diameter polyester mesh. A planar mat of roots was formed on the mesh in the top compartment, and the soil on the other side of the mesh in the lower compartment was cut into thin slices parallel to the rhizosphere and analysed for pH and P fractions. All plant species acidified the rhizosphere (pH [water] difference between bulk and rhizosphere soils was 0.17-0.26) and caused more rock to dissolve in the rhizosphere (10–18%) than in the bulk soil (8–11%). Guinea grass was most effective, though the rate of acidification per unit root surface area was least (0.02μmol H⁺ cm^?2) among the four species. Tea produced the largest rate of acidification per unit root surface area (0.08μmol H⁺ cm⁺²). All species depleted P extracted by a cation–anion exchange resin and inorganic P extracted by 0.1 M NaOH. All except tea depleted organic P extracted by 0.1M NaOH in the rhizosphere. The external P efficiencies (mg total P uptake) of Guinea grass, bean, tea and calliandra in soil fertilized with phosphate rock were 4.82 ± 0.42, 4.02 ± 0.32, 1.06 ± 0.02 and 0.62 ± 0.02, respectively, and the corresponding internal P efficiencies (mg shoot dry matter production per mg plant P) were 960 ± 75, 1623 ± 79, 826 ± 33 and 861 ± 44. This study showed that the various crops cultivated in tea lands differ in their rates of acidification, phosphate rock dissolution and P transformation in the rhizosphere. This requires testing under field conditions.     

高压液相色谱法同时测定植物组织中六种细胞分裂素组分和生长素

利用高效液相色谱研究了植物组织中六种细胞分裂素组分和生长素含量的测定方法。结果表明,采用反相色谱柱Hibar.RT250-4.6,在45℃恒温下以甲醇1%乙酸(40/60,v/v)溶液为流动相0、.6.mL/min等度洗脱,在=269.nm处能准确检测出植物组织中六种内源细胞分裂素组分和生长素的含量,检测限低至0.001.mg/L。本研究对样品的提取和纯化过程也做了改进,排除了杂质和色素对样品的干扰,为研究植物体内源激素对环境响应特征提供了有效的测定方法。     

固相萃取-高效液相色谱串联质谱法同时测定有机肥料中13种抗生素残留

建立了同时测定有机肥料中磺胺类、四环素类和喹诺酮类13种抗生素残留的高效液相色谱-串联质谱法,并对样品的前处理方法、仪器分析参数进行了优化。结果表明,13种抗生素在50~1 000 ng/mL间线性关系良好,相关系数均达到0.999以上,检出限在0.02~0.04 mg/kg,样品加标回收率在69%~111%之间,具有良好的重现性。该方法具有灵敏度高、准确度高等优点,可用于有机肥料中13种抗生素残留的同时检测。运用该方法在有机肥料实际检测中发现恩诺沙星、诺氟沙星、土霉素等抗生素残留。     

Soil carbon sequestration,plant nutrients and biological activities affected by organic farming system in tea (Camellia sinensis (L.) O. Kuntze) fields

There is growing interest in investigations into soil carbon (C) sequestration, plant nutrients and biological activities in organic farming since it is regarded as a farming system that could contribute to climate mitigation and sustainable agriculture. However, most comparative studies have focused on annual crops or farming systems with crop rotations, and only a few on perennial crops without rotations, e.g. tea (Camellia sinensis (L.) O. Kuntze). In this study, we selected five pairs of tea fields under organic and conventional farming systems in eastern China to study the effect of organic farming on soil C sequestration, plant nutrients and biological activities in tea fields. Soil organic C, total nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg), available nutrients, microbial biomass, N mineralization and nitrification were compared. Soil pH, organic C and total N contents were higher in organic tea fields. Soil microbial biomass C, N and P, and their ratios in organic C, total N and P, respectively, net N mineralization and nitrification rates were significantly higher in organic fields in most of the comparative pairs of fields. Concentrations of soil organic C and microbial biomass C were higher in the soils with longer periods under organic management. However, inorganic N, available P and K concentrations were generally lower in the organic fields. No significant differences were found in available calcium (Ca), Mg, sodium (Na), iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) concentrations between the two farming systems. These findings suggest that organic farming could promote soil C sequestration and microbial biomass size and activities in tea fields, but more N-rich organic fertilizers, and natural P and K fertilizers, will be required for sustainable organic tea production in the long term.     

Microsatellite variability within and among local landrace populations of tea, Camellia sinensis (L.) O. Kuntze, in Kyoto, Japan

Genetic variability within and among eight landrace populations of tea (Camellia sinensis (L.) O. Kuntze) located in southern Kyoto, Japan, was surveyed with six microsatellite markers. The average number of alleles per locus was 3.83 to 4.67 for landrace populations, whereas the corresponding value among modern cultivars and breeding lines was 6.63. Expected heterozygosity values averaged over loci within landrace populations ranged from 0.498 to 0.723. A similar level of variation, 0.682, was observed for cultivars and breeding lines. High fixation index values (0.177–0.417) for each population are consistent with biparental inbreeding within the population. Genetic differentiation among local populations was extremely low with F _ST = 0.062, although AMOVA revealed significant differentiation among landrace populations. We propose that these populations share a common ancestral gene pool and that some degree of artificial selection within each population has been performed by local farmers. Neighbor-joining analysis revealed that genetic relationships among populations reflect geographical location of populations. This might result from more frequent genetic exchange by nearby farmers.     

Influence of cultivar on quality parameters and chemical composition of strawberry fruits grown in Brazil

Six strawberry cultivars grown on the same commercial plantation in Brazil were evaluated for their chemical composition and quality attributes at the ripe stage. The profiles of the main soluble sugars, ascorbic acid, and anthocyanins were also obtained during the developmental stages. Results showed significant differences among cultivars in all of the investigated parameters. Cv. Campineiro showed an average value for texture of 0.63 N, half the value found for cv. Oso Grande. Anthocyanin content ranged from 13 (cv. Campineiro) to 55 (cv. Mazi) mg/100 g. Total ascorbic acid found for cv. Campineiro (85 mg/100 g) was twice the amount found in cv. Dover (40 mg/100 g). Fructose was the predominant soluble sugar in almost all cultivars. The proportion among the main soluble sugars (fructose, sucrose, and glucose) was similar for Oso Grande and Toyonoka cultivars. The flavonol content (quercetin plus kaempferol derivatives) ranged from 2.7 to 7.1 mg/100 g, with a mean value of 6.1 mg/100 g, whereas free ellagic acid ranged from 0.9 to 1.9 and total phenolics varied from 159 to 289 (mean 221) mg/100 g.     

Simultaneous determination of thiamin and riboflavin in mushrooms by liquid chromatography

A simple, fast, inexpensive, and reliable method useful for the simultaneous, routine determination of thiamin and riboflavin in mushrooms is examined. It uses the extraction procedure, with slight modifications, proposed by the AOAC for the extraction of thiamin and riboflavin, followed by a liquid chromatographic separation on a reversed-phase Spherisorb ODS column with methanol/water as mobile phase gradient. Fluorometric detection is used at the following excitation and emission wavelengths, respectively, 360 and 425 nm in the case of thiamin and 422 and 515 nm for riboflavin. The analytical parameters of linearity, the precision of the method (RSD = 2.45 and 2.51% for thiamin and riboflavin, respectively), and the results of the comparison with the corresponding AOAC fluorometric methods show that the studied method is useful for the measurement of thiamin and riboflavin in fresh mushrooms.     

Simultaneous determination of thiamine and riboflavin in foods by liquid chromatography

Recent methods for determination of thiamine (thiochrome) and riboflavin by liquid chromatography (LC) are outlined and discussed, and a new method allowing the simultaneous determination of these 2 vitamins by using a single fluorescence detector is described. This system involves an ODS 5 micron ultrasphere column and a pH 7.5 mobile phase composed of 0.005M tetrabutyl ammonium phosphate in methanol-water (20 + 80).     

Fast determination of catechins and xanthines in tea beverages by micellar electrokinetic chromatography

Antioxidant properties and stimulating effects of green tea are related to its content of cathechins and xanthines; tea quality evaluation is based on organoleptic tests and on the presence of those components. In this work, by a MEKC method, eight cathechins and three xanthines were quantified in some tea-based beverages. The best separation was realized using a phosphate-borate running buffer, with sodium dodecyl sulfate as micellar agent. A 40 cm capillary, a temperature of 29 degrees C, a voltage of 30 kV, and UV detection at 200 nm were used. The method showed a very good sensitivity (limit of detection ranging from 0.0011 to 0.0051 microg/mL) and was applied to real tea samples to characterize their antioxidant content. Statistical studies were performed and showed a satisfactory reliability of the data.     

Simultaneous determination of 16 nucleosides and nucleobases by hydrophilic interaction chromatography and its application to the quality evaluation of Ganoderma

In order to develop a simple, efficient, and sensitive method for comprehensive analysis of the nucleosides and nucleobases in natural products, a zwitterionic hydrophilic interaction chromatography (ZIC-HILIC) method for the simultaneous determination of 16 nucleosides and nucleobases has been studied. A mechanistic study confirmed that ZIC-HILIC separation showed a mixed-mode effect of both hydrophilic and electrostatic interactions. This method was validated to be precise, accurate, and sensitive with overall precision (intra- and interday) less than 1.8% (RSD), and LOD and LOQ was in the range of 0.005-0.029 μg/mL and 0.018-0.096 μg/mL, respectively. With this method, the nucleosides and nucleobases in Ganoderma of different species (G. atrum, G. lucidum, and G. sinense) and origins were quantified. The results showed that the contents varied with the species and origins. With the aid of hierarchical cluster analysis (HCA), cultivated Ganoderma from different origins and species were successfully discriminated. It is for the first time that the content of nucleosides and nucleobases in G. atrum is reported and compared. Our data showed that HILIC had advantages as a useful and potential tool for the study of the bioactive components in Ganoderma as well as their quality control, and could therefore be used for the determination of the analytes in other natural products.