15 June 2014, Volume 34 Issue 3

    

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  Advances on the Research of Fungi in Pu-erh Tea

  ZHAO Zhenjun, LIU Qinjin

  Journal of Tea Science. 2014, 34(3): 205-212. https://doi.org/10.13305/j.cnki.jts.2014.03.001

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  During the process of Pu-erh tea post-fermentation, fungal action plays an important role in forming its specific flavor and taste. This paper summarizes the fungal colonization, the effect of fungi on the quality of Pu-erh tea and also introduces the safety of fungi.
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  Study on Antioxidant Activity of Volatile Components from Pu-erh Tea

  REN Hongtao, ZHOU Bin, QIN Taifeng, XIA Kaiguo, ZHOU Hongjie

  Journal of Tea Science. 2014, 34(3): 213-220. https://doi.org/10.13305/j.cnki.jts.2014.03.002

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  The change of aromatic components in Pu-erh tea during the pile-fermentation process were determined by SDE/GC-MS. The different volatile oils of Pu-erh tea were evaluated by DPPH and FRAP of antioxidant activity. The relationship between the antioxidant activity and the content of main volatile components were analyzed. The results showed that the contents of methoxybenzene compounds increased distinctively during the pile-fermentation process. Compared with the beginning of fermentation, the scavenging activities on DPPH radical and antioxidant activity by FRAP were increased gradually and improved by 100% and 296% respectively. The free-radical scavenging activities of DPPH radical and antioxidant activity by FRAP were highly correlated with the content of methoxybenzene compounds and linalool oxide compounds.
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  Effects of EGCG from Tea on Regulating Lipid Metabolism and Alleviating Liver Injury in Rats with Non-alcoholic Fatty Liver Disease

  YAN Yujun, LIU Zhonghua, LIN Yong, HUANG Jian′an, PENG Bin, JIANG Huajun

  Journal of Tea Science. 2014, 34(3): 221-229. https://doi.org/10.13305/j.cnki.jts.2014.03.003

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  Non-alcoholic fatty liver disease (NAFLD) is a pathological metabolic syndrome performed as the fat accumulation and/or fatty degeneration in the liver, which is directly relevant to lipid metabolic disorder. In order to investigate the effects of EGCG from tea on regulating lipid metabolism and alleviating liver injury in rats with NAFLD, NAFLD model rats were established by feeding a high fat diet, and then the rats of EGCG protective groups were given daily oral administration of EGCG with three doses of 10, 50 mg·kg^-1 and 100 mg·kg^-1, respectively. The results showed that, compared with the model group, EGCG could decrease serum levels of triglyceride (TG), total cholesterol (TC) and low density lipoprotein-cholesterol (LDL-C), increase serum level of high density lipoprotein-cholesterol (HDL-C), reduce activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum, and ameliorate liver oxidative stress. Also, histological analysis showed that EGCG could reduce the formation of lipid droplets in the liver cells, and RT-PCR analysis showed that EGCG could regulate the expression of genes involved in lipid metabolism. Taken together, these experiment results indicated that GCG from tea effectively alleviate lipid metabolic disorder and lipid-induced liver injury.
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  Effect of Liupao Tea on Glucose and Lipid Metabolism in Palmitate-induced Insulin Resistance 3T3-L1 Adipocytes

  TENG Cuiqin, LIU Zhonghua, GONG Shouji, PENG Yuxuan, Ma Rui

  Journal of Tea Science. 2014, 34(3): 230-238. https://doi.org/10.13305/j.cnki.jts.2014.03.004

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  To investigate the effect of Liupao tea on glucose and lipid metabolism in palmitate-induced insulin resistance 3T3-L1 adipocytes. Glucose intake decreased and insulin resistance was induced in 3T3-L1 adipocytes after incubation in 1mmol/L palmitate for 24 hours. Compared with the model group, the concentrations of glucose and NEFA decreased along with the increase of Liupao tea concentrations in medium. The mRNA expression of key enzyme for glycolysis of glucose (Hexokinase, 6-phosphofructokinase-1, and pyruvatekinase) and the Lipid-Metabolism-Related Enzymes (Sn-glycerol-3-phosphate acyltransferase) significantly increased in the Liupao tea groups comparing with model sample. Meanwhile the glucose transporter 4 mRNA expression was also increased and the acetyl-CoA carboxylase, protein tyrosine phosphatase 1B mRNA expression was decreased. Low doses of Liupao tea reduced carnitine palmitoyl transferase I mRNA expression while high doses significantly raised it. Research proved that Liupao tea were able to increase glucose uptake and activate the glucolipid metabolic pathways. Liupao tea showed the effect of improving insulin resistance induced by palmitate in 3T3 -L1 adipocytes.
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  Research on Synergistic Protection and Repairing Effects of EGCG and Theanine in Oxidative Damaged Cells

  LIU Xiaohui, JIE Guoliang, LIN Kang, WU Yuanyuan, WANG Yuefei, TU Youying

  Journal of Tea Science. 2014, 34(3): 239-247. https://doi.org/10.13305/j.cnki.jts.2014.03.005

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  This paper investigated the scavenging capacities of EGCG and theanine, the two main active components in tea, alone or synergistically on ABTS, DPPH and hydroxyl radicals in vitro were investigated. The oxidative injury experimental model of mouse macrophage (RAW 264.7) by H₂O₂ was established for measuring the oxidative level and antioxidative enzyme activities by EGCG and theanine. The results showed that EGCG and theanine showed synergistic effect on the scavenging of ABTS and hydroxyl radical except for the DPPH radical. EGCG and theanine could synergistically reduce the contents of reactive oxygen species and lipid peroxidation, and enhance the activity of GSH-Px on RAW 264.7, which meant that the combination of above two compounds could synergistically reduce the oxidative damage of the cells through improving the antioxidant capacity.
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  Studies on Daily Flight Activity and Adult Flight Capacity of Empoasca vitis Göthe

  BIAN Lei, SUN Xiaoling, CHEN Zongmao

  Journal of Tea Science. 2014, 34(3): 248-252. https://doi.org/10.13305/j.cnki.jts.2014.03.006

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  Empoasca vitis Göthe has two flight activity peaks in the morning (6:00-7:00) and evening (16:00-17:00). For adults, the mean flight distances, the mean flight times and the mean flight speeds measured at different times of day, show no significant difference. The mean no flight time of the adults will increase significantly at night (22:00-23:00), and that of the males is longer than the females at noon (12:00-13:00). The results will provide useful reference for biological characteristics analysis and field control of Empoasca vitis.
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  Community Structure and Diversity of Spiders in Tea Plantations in Yingde Region of Guangdong

  LI Jianlong, LI Huashou, LI Xiudi, LIU Jie, LI Jiaxian, TANG Hao, TANG Jingchi

  Journal of Tea Science. 2014, 34(3): 253-260. https://doi.org/10.13305/j.cnki.jts.2014.03.007

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  Spiders are the important natural enemy communities in tea plantation ecosystems. In order to understand the influence of two types of habitat management on the spider communities in terms of species composition, structure and diversity in tea plantations, samples were collected between June 2010 and May 2011 by using both clapping and trap methods, and from the tea plantations within small woodland (Ⅰ) and tea plantations with conventional production (Ⅱ) in Yingde Region of Guangdong. The number of predatory spiders was 1 551 in tea plantation Ⅰ with 16 families and 40 species, and their richness and abundance were higher than those in tea plantation Ⅱ. In addition, tea plantation Ⅰ had relatively more dominant species and individual numbers. The dominant species, Itatsina praticola, showed the largest number of individuals, accounting for 16.39% of the total. Species richness in tea plantation I was significantly higher than that in tea plantation Ⅱ, but the dominance index was lower. These results indicated that less human interference in the surrounding habitat of tea plantations could affect the natural habitat giving a relatively stable and rich ecosystem, and hence improve the protection of spider species diversity.
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  Application of Retention Index on Volatile Compound Identification of Tea and Development of Retention Index Database

  LIN Jie, CHEN Ying, SHI Yuanxu, WANG Xiaochang

  Journal of Tea Science. 2014, 34(3): 261-270. https://doi.org/10.13305/j.cnki.jts.2014.03.008

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  Standard mixture of n-alkanes and n-alkanes in samples were applied respectively to determine the retention index (RI) of tea volatiles. The linear correlation coefficients of retention time with carbon number for the two methods were both above 0.99, indicating quite good reliability for calculating RI. With the applying of RI, the correct identification rate of the volatiles increased from 46.67% to 74.67%. Meanwhile, RI enabled effective identification of the isomers contained in tea volatiles, and greatly increased the identification accuracy. Data in relevant literatures were summarized to construct a RI database for HP-innowax column. The RI database could also improve the efficiency of compound identification using HP-innowax column.
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  Simultaneous Determination of 11 Kinds of Pesticide Residues in Tea by HPLC-MS-MS

  LIU Yanhui, YU Changhong, LIU Yan, LIU Jian, ZHANG Ting

  Journal of Tea Science. 2014, 34(3): 271-278. https://doi.org/10.13305/j.cnki.jts.2014.03.009

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  A method for rapid determination of 11 kinds of pesticide residues in tea samples by matrix solid-phase disperse extraction and high performance liquid chromatography and tandem mass spectrometry was proposed. The pesticide residues in tea sample were firstly extracted by a mixture of V(acetonitrile):V(acetic acid)=99:1, and the extract was solid-phase disperse purified by PSA and then separated on a Waters Xterra MS C₁₈ column with a gradient system of a mixture of methanol and water with ammonium formate. Multi-reaction monitoring (MRM) was employed for quantitative determination. Eleven pesticide residues could be detected within 20 min. The linear range of 11 pesticide residue was 0-500 ng·mL ^-1 and the limits of detection were between 0.1-1.7 μg·kg^-1. The correlation rate was more than 0.9995. The average recoveries (spiked at the levels of 10-400 μg·kg^-1) ranged from 62.4% to 114.8% with relative standard deviation between 3.28% and 19.34%. After extraction and purification, 11 pesticide residues in 5 samples of different kinds of tea with significant variation in content were analyzed. And the residue content of 11 pesticides in green tea sample was 1.7-339.4 μg·kg^-1. Recoveries in this sample were ranged from 86.1% to 104.1% with relative standard deviations less than 20%. This method is accurate, sensitive, simple, rapid,safe and suitable for identification and quantification of multiple pesticide residues in tea.
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  Analysis and Structural Identification of Anthocyanin Components in Purple Buds and Leaves of Tea Plant

  LI Zhi, WANG Riwei, ZHANG Lixia, HAN Xiaoyang

  Journal of Tea Science. 2014, 34(3): 279-287. https://doi.org/10.13305/j.cnki.jts.2014.03.010

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  A rapid method for analysis of anthocyanins in purple buds and leaves of tea plant was established by high-performance liquid chromatography (HPLC) based on the screening of mobile phase and the optimization of elution gradient. Using the established HPLC method, nine major chromatographic peaks were separated from crude extracts of anthocyanins from purple buds and leaves of tea plant. Further, the ultraviolet-visible spectrum and mass spectrum data of seven out the nine components were obtained by HPLC-DAD-MS/MS analysis. Combined with the literature data, five major components of anthocyanins were identified as delphindin-3-galactoside, cyanidin-3-gal-actoside, delphindin-3-rutinoside, cyanidin-3-rutinoside, and pelargonium-3-rutinoside. Additionally, each component was quantitatively analyzed using an external standard method, and crude extracts of anthocyanins were obtained at the purity of 32%. The proposed method is convenient and rapid with high accuracy and reproducibility, which can be applied for determining anthocyanins in purple buds and leaves of tea plant.
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  Effect of Withering Light Intensity on Physical Characteristics and Respiration of Tea Fresh Leaves

  HUA Jinjie, YUAN Haibo, JIANG Yongwen, CHENG Gensheng, WANG Weiwei, LIU Ping

  Journal of Tea Science. 2014, 34(3): 288-296. https://doi.org/10.13305/j.cnki.jts.2014.03.012

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  Setting three different withering light intensities, the water content, bulk destiny, flexibility, elasticity, plasticity and color value, the released amount of CO₂ of the withering leaves were evaluated, and the effects of different withering light intensity on physical characteristics of rolled leaves, fermented leaves and fired tea were also analysed. The results showed that with the increasing of withering time, moisture content of tea fresh leaves decreased gradually, bulk destiny and elasticity of leaves increased at first and then decreased during withering, and were the highest at 6 000 lx in moderate range (the moisture content was between 60% and 65%), elasticity decreased at first and then increased, the elasticity of tea leaves were relatively highest when the withering light intensity was 6 000 lx, and the variation of plasticity was opposite, the L value (luminosity) declined generally, the “a” value (red and green degree) decreased at first and then increased, and it had the lowest value at 6 000 lx, namely the green keeping was the best, the results of sensory evaluation also showed that the liquor color and shape of black tea at 6 000 lx had the highest score, with the best quality, the released amount of CO₂ decreased at first, then increased and was stable finally, the urning point occurred during withering at 6 h, and the amount was the largest when the withering light intensity was 6 000 lx.
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  Isolation of CsRAV2 Transcription Factor Gene of Tea Plant and its Expression Analysis

  WU Zhijun, LI Xinghui, FANG Wanping, ZHOU Lin, ZHAO Zhen, ZHUANG Jing

  Journal of Tea Science. 2014, 34(3): 297-306. https://doi.org/10.13305/j.cnki.jts.2014.03.013

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  The RAV transcription factor, one subfamily of AP2/ERF family transcription factor, includes several genes that encode proteins involved in the development and regulation of abiotic/biotic resistance in higher plant. The CsRAV2 genes, which encoding to the RAV transcription factor, were cloned from tea plant (Camellia sinensis) cultivars ‘Anjibaicha’ and ‘Yingshuang’ by PCR and RT-PCR using DNA and cDNA as template, respectively. Then, nucleic acid and deduced amino acid sequence, phylogenetic tree, and molecular modeling were predicted and analyzed. The lengths of CsRAV2 genes from the two tea plant cultivars were 1 089 bp, encoding 362 amino acids. No intron was found in the CsRAV2 gene. The transcription factor of CsRAV2 contained two distinct DNA domains mainly found in higher plants RAV family factors, one AP2 domain together with one B3 domain. The CsRAV2 were hydrophilic protein. The protein of CsRAV2 from tea plant and AtRAV from Arabidopsis had similar three-dimension structure. Quantitative real-time PCR analysis of the expression profiles showed that the CsRAV2 gene was tissue-specific expressed in the two tea plant cultivars. The highest expression levels of the CsRAV2 gene were found in the root. The CsRAV2 gene was induced by high temperature, low temperature, PEG and high-salinity treatment, respectively. There were differences profiles between different teacultivars.
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  Application of Le Bissonnais Method to Study Soil Aggregates Stability in Tea Field

  WANG Shengqiang, ZHENG Zicheng, LI Tingxuan

  Journal of Tea Science. 2014, 34(3): 307-314. https://doi.org/10.13305/j.cnki.jts.2014.03.014

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  Through field investigation and laboratory analysis, soil aggregates stability in tea field was studied by Le Bissonnais method. Results showed that (1) the mass percentage of >5 mm soil aggregates expressed as wet stirring treatment (81.05%-95.62%)> slow wetting treatment (64.18%-89.31%)> fast wetting treatment (17.62%-24.26%) under different tea field age, and values of mean weight diameter (MWD), geometric mean diameter (GMD) and bias coefficient (C_S) of soil aggregates showed the same variation. The primary destructive mechanism of tea field soil aggregates was dissipation and fast wetting treatment was closer to the actual situation of tea field soil. (2) Stability of soil aggregates in response to continuous cropping of tea was significantly different under fast wetting treatment. Along with the increasing of planting age of the tea field values of soil aggregates MWD, GMD and C_S displayed a falling-and-rising trend, and lower values were found in tea fields with 23 years of age and showed that field soil aggregates stability was weakest in tea field with 23 years of age. (3) The stability of soil aggregates in tea field showed a positive correlation with contents of soil organic matter and clay under fast wetting treatment. The increased contents of soil organic matter and clay were beneficial to formation of soil aggregates and improved to stability of soil aggregates. Therefore, in management of tea fields, it is essential to increase the amount of straw covering the soil, so as to weaken the role of dissipation on soil aggregates disintegration, and in tea fields with 16 to 23 years of age, it was necessary to apply to use organic manure, so as to improve the stability of soil aggregates.