Journal of Tea Science

Study on the GCG in Green Tea

LU Hai-peng, TAN Jun-feng, GUO Li, GU Ji-ping, LIN Zhi

Journal of Tea Science. 2008, 28(2): 79-82. doi:10.13305/j.cnki.jts.2008.02.002

Abstract ( 517 )

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The GCG content in different tea germplasms, change of GCG content during green tea processing and the tea leaf treated with high temperature steam were studied by using the HPLC determination. Results showed that the content of GCG in five tested tea cultivars was more than 1.5% among 200 tea germplasms, and it was increased continuously during the green tea processing. Temperature was the key factor that influenced the GCG content in tea, and the high temperature steam treatment could effectively increase the GCG content in green tea.

Discriminant Classification of Production Area of Flatten-shaped Green Tea Based on Multiple Chemical Fingerprint

CHENG Hao, WANG Li-yuan, ZHOU Jian, YE Yang, LIU Xu, LU Wen-yuan

Journal of Tea Science. 2008, 28(2): 83-88. doi:10.13305/j.cnki.jts.2008.02.003

Abstract ( 410 )

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The method of Discriminanting Classification of Flatten-shaped Green Tea Production Area Based on Multiple Chemical Fingerprint was studied by way of using samples from single cultivar and from mixed cultivars, with three groups of samples produced in West Lake District Hangzhou, Xinchang County Shaoxin and Lishui respectively. The result showed that samples from three district could be distinguished effectively by using those discriminant method obtained form the investigation, whether single cultivar samples or mixed cultivar samples were used. The recognition accuracies of the training sample set and the test sample set were all 100% except one Yingshuang cultivar test sample. When using mixed samples of 9 cultivars, the recognition accuracy of the training sample set 143 samples was 93.7% and that the test sample set was 91.7%. Those above result revealed that it was possible to distinguish or verify the producing area attribute of flatten-shaped green tea products by combining the techniques of multiple chemical fingerprint and discriminant classification.

Determination of Theanine in Tea by Paired Ion Chromatography

GONG Yu-shun, HUANG Jian-an, CUI Xiang-xing, LI Qing, LI Yin-hua, CHEN Jin-hua

Journal of Tea Science. 2008, 28(2): 89-92. doi:10.13305/j.cnki.jts.2008.02.004

Abstract ( 491 )

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A paired ion chromatographic method was developed for rapid determination of theanine in tea. SDS was added as a paired ion reagent, mobile phase was a mixture of acetonitrile and phosphoric acid aqueous solution, detection wavelength was set at 200 nm. The retention time of Theanine was 6.27 min. The calibration of theanine was in good linearity in the range of 0.04~20 μg with the regression equation Y=1.51466×10⁶X+3.28706×10⁵(r²=0.99901). The detection limits was 1.15 ng(S/N=3). This method is rapid, simple, and accurate for the analysis of theanine in tea.

Determination of Trace Lead in Tea with Screen-printed Carbon Electrodes

ZHAO Guang-ying, WU Yan-yan

Journal of Tea Science. 2008, 28(2): 93-100. doi:10.13305/j.cnki.jts.2008.02.005

Abstract ( 433 )

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The square wave anodic stripping voltammetric (SWASV) methodology using a screen printed carbon electrode (SPCE) in situ plated in mercury (Ⅱ) was developed by the authors to determine lead in tea. A detailed description of the systematic laboratory test carried out to optimize its performance is reported. A series of optimum parameter are as follows Hg²⁺concentration: 4×10^-4 mol/L, Plating potential: -1.1 V, E_step: 3 mV, Frequency: 10 Hz, Amplitude: 60 mV, pH: 5, plating time: 280 s, balance time: 30 s. Under the optimized analytical condition, the obtained sensitivity, linearity, and detection limit are 22.7 nA/(μg/L), 10~225 μg/L (r=0.9986), and 0.74 μg/L(S/N=3),respectively. The interference effect was thoroughly studied with various metals in the determination of 120 μg/L Pb²⁺. Tea was digested using domestic microwave oven and PTFE sealed and pressurized microwave digestion tank. The standard method of analysis was used to detect the samples and comprised with the GB method, no significant deviation was found. The method was sensitive, accurate, fast and suitable for the determination of trace lead in tea.

Determination of the Total Content of Polyphenols in Kudincha by Folin-Ciocalteu Colorimetry

LIU Li-xiang, Tanguy Laura, LIANG Xing-fei, SUN Yi, YE Hong, ZENG Xiao-xiong

Journal of Tea Science. 2008, 28(2): 101-106. doi:10.13305/j.cnki.jts.2008.02.006

Abstract ( 609 )

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A quantitative method for the determination of the total content of polyphenols in kudincha was studied by using FC method (Folin-Ciocalteu colorimetry ) with chlorogenic acid as standard. The results showed that the total polyphenol contents of kudincha could be well calculated according to their colorimetric absorption at 747 nm by applying Folin-Ciocalteu reagent 3.0 ml and saturated Na₂CO₃4.5 ml at 30℃ for 30 min, and the linear range of standard curve was 20.0~100.0 mg/L. Stability, precision, repetition and recovery rate were in the range of 0.887%~1.416% by RSD (relative standard deviation). There are not any differences for the results obtained by FC method and ferrous tartrate colourimetry. Therefore, FC method is convenient, fast, and accurate to determine the total polyphenols of kudincha.

The Regulation of Oolong Herb Tea on the Serum Lipid Level and the Preventive Effects of ECV in Experimental Hyperlipidemia Rats

ZHENG Liang-pu, LIN Wei, YE Hong-zhi, CHEN Wen-lie, HU Hai-xia

Journal of Tea Science. 2008, 28(2): 107-110. doi:10.13305/j.cnki.jts.2008.02.012

Abstract ( 461 )

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To establish the hyperlipidmia rat models by feeding high lipid diet, then the herb, tea and oolong herb tea were irrigated into stomach separately for 35 days in succession, the level on the activity of ALT, AST enzyme and the level of cholesterols of TCHO, TG, HDL-C, LDL-C, as well the contents of NO and ET-1 in rat blood measured were measured. Meanwhile, the general conditions and histopathological changes in tissues of liver and kidney were observed to explore the influence of Oolong herb tea on the serum lipid level and the preventive effect on vein endothelium cells in experimental hyperlipidemia rats investigated. Results showed that compared the blood levels of TCHO, TC, LDL-C, TCHO and the ET-1 content were reduced significantly in treatment group while HDL-C and NO increased(P<0.05, P<0.01) compared with the control group. The effect of Oolong herb tea was more remarkable than that of herb and tea treatment. It is concluded that the herb, tea and Oolong herb tea are able to regulate the level of serum lipid effectively prevent hyperlipidemia and have a protective effect of vein endothelium cells. It is showed that the synergistic effect between herb and tea and improve the efficacy in Oolong herb tea.

Deodorizing Effect of Tea Functional Ingredients on Methyl Mercaptan

GONG Yu-shun, HUANG Jian-an, LIU Zhong-hua, WANG Kun-bo, YANG Zhi-hui

Journal of Tea Science. 2008, 28(2): 111-114. doi:10.13305/j.cnki.jts.2008.02.007

Abstract ( 791 )

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The deodorizing effect of tea functional ingredients on methyl mercaptan (CH₃SH) was studied in this investigation. The results indicated that green tea extracts, catechins and EGCG showed deodorizing negative effect on methyl mercaptan, while theaflavins was effective. When dissolved in pH10 alkaline solution, theaflavins showed extremely strong activity, and the effectiveness against methyl mercaptan reached 0.232 mg separately per 1 mg 40% theaflavins.

Protective Effects of Camellia angustifolia Chang on Oxidative Stress-induced Liver Damage in Mice

GU Chen-fei, BAO Li, XIE Guo, LU Yan-qing, YAO xin-sheng, Kurihara Hiroshi

Journal of Tea Science. 2008, 28(2): 115-122. doi:10.13305/j.cnki.jts.2008.02.013

Abstract ( 419 )

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To investigate the protective effect of Camellia angustifolia Chang extracts (CA. extracts) on restraint stress-induced liver damage in mice, The mice model of stress-induced liver damage was used in investigation. After 18βh restraint stress on mice 4 days following CA. extracts treatment, the liver damage was established. Alanine aminotransferase (ALT) and xanthine oxidase(XOD)activities, malondialdehyde (MDA) contents, GSH levels, GPX and GST activities, as well as oxygen radical absorbance capacity (ORAC) values in liver were determined to evaluate the hepatoprotective effects. Compared with restraint model group, CA. extracts can markedly reduce ALT activities, MDA contents and XOD activities, protect the liver damage induced by oxidative stress. Additionally, CA. extracts can effectively increase the ORAC values both in vivo and in vitro, as well as GSH levels, GPX activities and GST activities. Oral treatment of CA. extracts was found to reduce restrain-stress-induced liver damage in terms of above mentioned biochemical parameters, it is considered that this protective effects may be related to its free radical scavenging activity and lipid peroxidation inhibitory effects.

Study on Nutritional Function of Bacterial Bio-fertilizer on Tea Plant

ZHANG Ya-lian, CHANG Shuo-qi, LIU Hong-yan, FU Hai-ping, LI Jian-quan

Journal of Tea Science. 2008, 28(2): 123-128. doi:10.13305/j.cnki.jts.2008.02.010

Abstract ( 503 )

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The phosphorus-releasing and potassium-releasing ability of two species of bacterium in soils of tea garden (pH5.5~6.5) was investigated under laboratory condition. The amounts of bacterium per unit volume were ascertained by the absorbance of culture solution under special wavelength and various pH. Results showed the absorbance was relatively high under pH5.5~6.5, that meant these bacterium grew well under the above pH range: the bacterial bio-fertilizer made of bacterial fermentation liquid and rapeseed cake can enhance the contents of fast-acting phosphorus and potassium, improve the growth of tea shoots and increase the tea yield after applied in the soils of tea garden. Results indicated that the selected bacterial strain and the produced bio-fertilizer showed good effectiveness in proving the soil fertility and growth of tea plant and increase the yield of tea garden.

Effect of Natural Minerals on Immobilization of Lead in Soils of Tea Garden

WANG Hao, ZHANG Ming-kui

Journal of Tea Science. 2008, 28(2): 129-134. doi:10.13305/j.cnki.jts.2008.02.011

Abstract ( 393 )

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The soluble and exchangeable fractions of Pb in the tea garden soils are the most important pools regarding toxicity and bioavailability of Pb to tea plants. Thus, it is very important to reduce Pb solubility and bioavailability in Pb-contaminated tea garden soils. Reducing Pb solubility and bioavailability in contaminated area without removing it from the soil is one of the common practices in decreasing the negative impacts on the crops and improving the soil quality. Therefore, the aim of this work was to study the effect of natural minerals: kaolinite, bentonite, zeolite,and apatite applied to Pb-contaminated tea garden soil on water extractable and exchangeable forms of Pb. A soil derived from Pb contaminated tea garden was incubated with clay minerals of either kaolinite, bentonite, zeolite,or apatite, for 100 d. During the incubation experiment, concentrations of exchangeable and water soluble Pb in the soils were measured. Water extractable and exchangeable forms of Pb were changed by incubation and addition of minerals. The addition of clay minerals led to a significant decrease in water soluble and exchangeable forms of soil Pb during the incubation experiment, resulting in low Pb extractability. The reduction in Pb extractability decreased in the order of apatite > zeolite > bentonite> kaolinite, and increased with increasing applied amount of the minerals and decreasing size of the minerals. The reduction in water soluble Pb due to the addition of the minerals was greater than that of exchangeable Pb in the soils. Our results clearly show that the use of natural minerals, especially of apatite and zeolite, is promising tool for reduction the availability and possible toxicity of Pb in Pb-contaminated tea garden soils. Therefore, the soils polluted with Pb may be ameliorated by addition of clay minerals, especially apatite and zeolite. Recommended amount of minerals for ameliorating Pb-contaminated soil is 20 g/kg.

The Microscopic Analysis of Yellow-Greenish Spontaneous Fluorescence in the Tea Leaves of Fluorescent Green Spot Disease

JIANG Shu-yuan, ZHANG Li-xia, GUO Yan-kui, ZHAO You-quan, JIA Ming, ZHAI Heng

Journal of Tea Science. 2008, 28(2): 135-141. doi:10.13305/j.cnki.jts.2008.02.009

Abstract ( 443 )

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The fluorescent green spot disease is a physiological disease of tea mature leaves. The green spots on the leaf back emit yellow-greenish fluorescence. In order to investigate the rule of the disease occurrence by using spontaneous fluorescence as a probe and the spectra of yellow-greenish fluorescent compounds for their isolation and identification, the fluorescence microscopy, microscopic fluorescence spectral imaging, laser scanning confocal microscopy and flow cytometry were used in this investigation. This experiment covered the condition of microscopic observation, emission spectral characters of yellow-greenish spontaneous fluorescence and their localization in the diseased tea leaves. Results showed that the diseased leaves could emit several kinds of spontaneous fluorescence by irradiating different lights, and the optimal microscopic condition for observing the yellow-greenish fluorescence was that the diseased leaves were excited by blue light and images recorded in multicolor and green color mode, in which there were three fluorescence peaks at 515 nm, 535 nm, and 585 nm within the light range of yellow and green. The yellow-greenish fluorescence were firstly emitted in the sheath cell of vascular bundle and then in the barrier cells, sponge cells and the epidermis cells. And the location of fluorescence was the vacuole of the diseased cells.

Electronic Scanning Analysis on the Carbon Particle in the Exhaust Air of Diesel Engine Burning Tea-Seed Oil

MA Rong-chao, WU Wei-xiong, QIN Wen, HUANG Mei, CHEN Chuan

Journal of Tea Science. 2008, 28(2): 142-146. doi:10.13305/j.cnki.jts.2008.02.008

Abstract ( 416 )

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Vegetal energy is becoming one of the important energy sources for diesel engine. On the basis of the burning character research of tea-seed oil on diesel engine, material handling was applied to the tea-seed oil. With the processed oil, burning test was carried out on the S195 diesel engine, and micro electronic scanning apparatus was applied to measure the carbon particle in the exhaust air. And the result shows that it is feasible to burn tea-seed oil or mixture oil of tea-seed oil and diesel oil without changing the basic structure of the engine while with better burning performance, the carbon deposit in the combustion chamber and on the oil nozzle as well as the exhaust contaminant drops. So the undergone material handling tea-seed oil has better burning character than the diesel oil or the mixture of tea-seed oil and diesel oil without material handling.

Study on the Plasmid Stability of the Genetically Engineered Escherichia coli Bacteria Strain for the Biosynthesis of Theanine

LU Wen-yuan, CHENG Hao, WANG Li-yuan, ZHOU Jian

Journal of Tea Science. 2008, 28(2): 147-151. doi:10.13305/j.cnki.jts.2008.02.001

Abstract ( 437 )

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The stability of the recombinant plasmid pET32a-GGT in the genetically engineered E. coli bacteria strain for the biosynthesis of theanine was in investigated this article. Result showed that the recombinant plasmid didn’t appear obvious gene deletion, showed structural stability after 100 generations. However, the plasmid is showed segregational instability, the plasmid-free cells appeared after 20 generations, and 18% cells was plasmid-harboring cells after 100 generation under no Amp selection pressure. It was structural and segregational stability under optimizing culture medium and condition during the fermentation process, with activity ofγ-GGT 4.64 U/ml and yield of theanine 35.18 g/L.

Aesthetic Image of Tea in the Tea Poems Written in Tang and Song Dynasty

ZHU Hai-yan, LIU Zhong-hua, LIU De-hua, SHI Zhao-peng

Journal of Tea Science. 2008, 28(2): 152-156. doi:10.13305/j.cnki.jts.2008.02.014

Abstract ( 529 )

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In modern society the relationship between tea and daily life becomes more and more intimate, and the effects of tea culture are so profound that the study upsurges have come. In view of existing situation a new study point cut-in from aesthetics was explored. In this article, knowledge of aesthetics, tea science, poem science and history science were synthetically applied to analyze the beauty of shapes, colors, fragrances, flavors of tea expressed in many exquisite tea poems written in Tang and Song Dynasty. The results vividly traced out extremely clean and perfect taste image of tea, and enriched the themes and contents of poems studies, filled up the study blank of tea poem aesthetics.

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