15 February 2012, Volume 32 Issue 1

    

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  Progress in the Research of Biosynthesis of Volatile Terpenoids and Their Glycosides in Tea Plant

  HE Zhi-rong, XIANG Wei, XU Yan, GAO Li-ping, XIA Tao, WEI Shu

  Journal of Tea Science. 2012, 32(1): 1-8. https://doi.org/10.13305/j.cnki.jts.2012.01.008

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  Tea aromatic quality is largely dependent on the spectrum and abundance of volatile terpenoids and their glycosides produced and accumulated in tea leaves. Very often, the compounds of monoterpenes (C₁₀) and sesquinterpene (C₁₅) possess pleasant floral scent, contributing significantly to tea aromatic quality. However, studying on the biosynthesis pathway of these volatile terpenoids and their glycosides in tea plant is just at beginning. In this review, speed-limiting biosynthetic steps and related enzymes in plant volatile terpenoid biosynthesis pathways are summarized. The genes encoding 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) and 3-hydroxyl-3-methylglutaryl-CoA reductase (HMGR) as well as terpenoid synthases are proposed as key enzymes for volatile terpenoid biosynthesis. Uridine diphosphate-glycosyltransferase may affect biosynthesis and accumulation of glycosides of volatile terpenoids in tea plant while glycosidase play a key role in the glycoside hydrolysis and release of glycosidically bound terpenoid volatiles during tea leaf processing. Manipulation of these genes may control the flux of the terpenoid metabolism towards the volatile terpenoid biosynthesis. The factors influencing tea aromatic quality such as tea cultivars, growing management, processing ways are also discussed.
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  Investigation and Comparison of the Aroma Components in Guangdong Black Tea

  WANG Qiu-shuang, CHEN Dong, XU Yong-quan, YIN Jun-feng

  Journal of Tea Science. 2012, 32(1): 9-16. https://doi.org/10.13305/j.cnki.jts.2012.01.002

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  For the purpose of studying the volatile aroma components in Guangdong black tea and determine the main aroma components, the headspace solid-phase micro-extraction method and gas chromatography-mass spectrometry were used to determine the aroma compounds in black tea samples and their contribution to the total aroma. Results showed that more than 50 aroma compounds were identified including alcohol, ester, aldehyde, ketone, terpene, hydrocarbon etc., among which the alcohol was the most important compounds and ester and aldehyde were next to flower-like, fruit-like, refreshing and sweet aroma were the main character of Guangdong black tea. Linalool, gerariol, methyl salicylate, linalool oxide and nonanal were the five most important compounds, representing 37.55%, 11.90%, 8.89%, 5.4% and 5.21% of the total aroma respectively. The alcohol was the most important compounds in Yingde tea population, the contents of aldehyde and ketone were more in Baimao tea population. Dancong and Fujian tea plant contained more terpene compounds.
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  Effect of Extraction Temperature on Tea Sediment Formation in Green Tea Infusion

  XU Yong-quan, CHEN Gen-sheng, LIU Ping, ZHONG Xiao-yu, YUAN Hai-bo, YIN Jun-feng

  Journal of Tea Science. 2012, 32(1): 17-21. https://doi.org/10.13305/j.cnki.jts.2012.01.003

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  The effect of different extraction temperature (20~100℃) on the content of main chemical components, reversible and irreversible sediment amount of green tea infusion was investigated. The results showed that, with the increasing of extraction temperature, the solid concentration, content of main chemical components and the amount of reversible and irreversible tea sediment all significantly increased. When the extraction temperature was lower than 40℃, there was only a small amount of tea sediment and irreversible tea sediment formed. When the extraction temperature increased from 50℃ to 90℃, the solid concentration increased a little, but the more tea sediment amount increased. If the extraction temperature is lower than 50℃, the formation of tea sediment will be decreased greatly.
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  Analysis of Fatty Acid Composition in the Seed Oilfrom Fujian Tea Germplasm

  CHANG Yu-xi, ZHENG De-yong, YE Nai-xing, YANG Jiang-fan

  Journal of Tea Science. 2012, 32(1): 22-28. https://doi.org/10.13305/j.cnki.jts.2012.01.011

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  The fatty acid compositions of 42 cultivars of tea seeds oil from Fujian province were determined by GC. The results indicated that the average content of saturated fatty acid (SFA) was 20.59%, the monounsaturated fatty acid (MUFA) was 50.57%, and the PUFA was 28.11%. The DHA with a mean of 0.11% was discovered in tea seeds. The investigated fatty acid compositions of fine cultivars were better than that in local cultivars. The major compositions of tea seeds oil were stearic acid, arachidic acid, palmitic acid and DHA. When 11 kinds of higher contents and special compositions were chosen as principal component analysis. The results showed that tea seeds oil possesses a high level of oleic acid, linoleic acid, and low levels of erucic acid and TFA. The tea seeds showed a potential value in the development of high grade edible oil.
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  Influence of Extrusion Parameters on Crude Fiber in the Extruded Green Tea Leaves

  WANG Bo, YE Yang, ZHOU Xiao-fen, QIAN Yuan-feng

  Journal of Tea Science. 2012, 32(1): 29-36. https://doi.org/10.13305/j.cnki.jts.2012.01.004

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  Extruded green tea leave processed with a twin screw extruder, using response surface design method to establish the regression model between the moisture content of material, feeding speed, rotational speed of screw, temperature of barrel and the content of crude fiber in the green tea leaves. The results showed that the significance of parameters on the content of crude fiber in the green tea dregs was decreased according to the order of rotational speed of screw>temperature of barrel>feeding speed>moisture content of material. The optimal parameters of low content of crude fiber in the green tea dregs were as follows: moisture content of material 70%, feeding speed rotational 90r/min, speed of screw 90r/min and temperature of barrel 50℃. At this point, the content of crude fiber in the tea dregs was around 15%, compared with the raw materials before extrusion, the content of crude fiber decreased 3%.
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  Study on the Influence of Immobilized Cellulase on the Summer Tea Extract

  WANG Jia-hui, LI Yan, YAO Zi-han, WANG Jia-jian

  Journal of Tea Science. 2012, 32(1): 37-43. https://doi.org/10.13305/j.cnki.jts.2012.01.005

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  Immobilization of cellulase on carrier of chitosan beeds crosslinked by glutaraldehyde were studied, and applied the immobilized cellulase to the hydrolysis of the summer green tea. Through the orthogonal test, the optimal extract technology has been investigated: adding 1.0g immobilized cellulose enzyme in 1.0g green tea, the ratio of tea and water is 1∶20,and extracted 50min under 55℃. Compared to the traditional tea extraction method by hot water, the contents of tea polyphenols, amino acid and caffeine increased by using this technology, and the ratio of polyphenol to ammo acid was decreased. The immobilized cellulase still maintain a high activity, the relative activity of enzyme was more than 80%, after 7 times extraction.
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  Optimization on Processing Parameters for Biodiesel from Tea Seed Oil

  PENG Zhong-jin, MA Cheng-jin, XIAO Wang, HUANG Ting, ZHENG Jun-xiao, XIANG Yong-ping

  Journal of Tea Science. 2012, 32(1): 44-52. https://doi.org/10.13305/j.cnki.jts.2012.01.001

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  Methyl esterification preparation of biodiesel from tea seed oil was investigated. According to single factor investigation, a mathematical model with transesterification ratio as a response to reaction temperature, catalyst dosage, reaction time, mole ratio of methanol to oil was established using Box-Behnken central composite experimental design. This was followed by response surface analysis. It was found that the optimal process conditions for methyl esterification of tea seed oil were as follows: reaction temperature 58℃, catalyst dosage（mass percent to oil）1.05%, reaction time 66min, mole ratio of methanol to oil 9.7∶1, and that the resultant transesterification ratio was 98.79%. Fourier transforms infrared spectroscopy and GC/MS were used to analyze biodiesel, and the quality indexes of biodiesel in the experiment reached the national biodiesel standards of Chinese.
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  mRNA Differential Expressionof Camellia sinensis under Drought Conditions

  CHEN Sheng-xiang, QI Gui-nian, XIA Jian-bing, ZOU Yao, SHAN Hong-li

  Journal of Tea Science. 2012, 32(1): 53-58. https://doi.org/10.13305/j.cnki.jts.2012.01.012

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  20% PEG-6000 was used for simulating drought treatment to Camellia sinensis cv. Fuding-dabaicha clone. mRNA differential display reverse transcriptase polymerase chain reaction (DDRT-PCR) was used to study the mRNA differential expression between drought stress and irrigated contro1. One down regulated gene was found under drought stress. Sequence analysis and homology alignment showed that N_3-5 showed 75% homogenicity with the Camellia sinensis clone Sajin tea leaf mutant color tag S31.B15 genomic sequence (Accession：DQ443473.1). It was suggested that the fragments N_3-5 was related to drought tolerance mechanism of tea plant according to the functions of their homologous sequences.
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  Analysis of Differential Gene Expression on Specific Tea Cultivar “Zijuan” for Leaf Color Changing

  CHEN Lin-bo, XIA Li-fei, SUN Yun-nan, LIANG Ming-zhi, ZHANG Zheng-zhu, LI Ye-yun, WAN Xiao-chun

  Journal of Tea Science. 2012, 32(1): 59-65. https://doi.org/10.13305/j.cnki.jts.2012.01.013

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  Differences of gene expression between young and mature leaves of tea plant (Camellia sinensis var. assamica, cultivar Zijuan) were studied by cDNA-AFLP. The results showed that 59 Transcript-Derived Fragments (TDFs) were obtained, including 26 up-regulated TDFs from young leaves, and 33 up-regulated TDFs from mature leaves. According to blasting results, these TDFs were included signal transduction genes, transcription factors, primary metabolism genes, putative protein and unknown protein and no significant homology found. RT-PCR was used to analyze the expression of ZM4, ZM7, ZM12, showed that expression of these ZM4, ZM7, ZM12 increased obviously in mature leaves. This study established a basis for further understanding the purple mechanism of tea leaves in cultivar “Zijuan” and related gene cloning.
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  Perspective of Financing Risk from the Differentiationin Fujian Tea Enterprises

  YANG Jiang-fan, XU Qing, XIE Xiang-ying, GUAN Xi, GAO Shui-lian, CHEN Qian

  Journal of Tea Science. 2012, 32(1): 66-72. https://doi.org/10.13305/j.cnki.jts.2012.01.009

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  Some questionnaires were used in 221 Tea Corporations in cities and towns of Fujian, which mainly producing and marketing tea, to survey the advantage of differentiation, and the results elarified the situation of financing in these corporations and the risk under it. Conclusions indicated that Fujian tea enterprises were small to micro in scale basically, which mostly meet its financial needs through financial institutions such as banks and cooperative, mainly related to financing, deposit, settlement, etc. In view of the big financing risk, financing and loans problems were prevalent among tea enterprises. Constructing institutional framework to crack the financing risk of Fujian tea enterprises should start with system innovation of the financial institutions, credit protection of industry associations and policy supporting of functions.
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  Technical Regulations and Sino-Japan Tea Trade:Evidence from Disaggregation Data

  JIANG Tao, ZHANG Yong, LUO Jian-yi, QIN Qiong-xia

  Journal of Tea Science. 2012, 32(1): 73-80. https://doi.org/10.13305/j.cnki.jts.2012.01.006

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  The paper analyzed the differenct impact on Sino-Japan tea trade by technical regulations between and within 4 digital and 6 digital of HS. It was discovered that the significant differences were existed in the influence of technical regulation under the HS catalogue of 4 digital and 6 digital. Forthmore, the black tea and green tea of big package are significant influenced by Japan technical regulation, and not significantly affected on the small-single pachage of black and green tea. This investigation provided a more efficient idea on the active of the international technical regulation in the China tea trade.
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  The Anti-obesity Effects of Fuzhuan Brick Tea on High-fat-diet Induced Obesity in Rats

  WANG Die, HUANG Jian-an, YE Xiao-yan, CAO Dan, ZHANG Jian-wei, LIU Zhong-hua

  Journal of Tea Science. 2012, 32(1): 81-86. https://doi.org/10.13305/j.cnki.jts.2012.01.007

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  The aim of the study was to investigate the anti-obesity effects of the Fuzhuan brick tea and green tea on a high-fat-diet induced rat model. Experimental groups were given daily oral administrations of tea aqueous extracts at different concentrations, which yields doses of 75mg/kg, 150mg/kg or 300mg/kg. The results showed that the body weight gains and the weights of perinephric fat pads and epididymal adipose tissues were significantly reduced in rats administrated with tea aqueous extracts compared with the model control group. Supplementation with tea aqueous extract decreased the values of the food utilization efficiency, fat coefficient and Lee’s index. Histological analysis in the present study showed that both tea aqueous extracts had suppressive effects on the number and size of the adipose tissue fat cells. Moreover, serum levels of the triglycerides of the Fuzhuan brick tea groups are lower than that of the green tea groups.
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  Effect of Theabrownin Extracted from ‘Zijuan’ Pu-erh Tea on Growth of Rats with Hyperlipidemia Food

  WANG Qiu-ping, GONG Jia-shun

  Journal of Tea Science. 2012, 32(1): 87-94. https://doi.org/10.13305/j.cnki.jts.2012.01.010

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  The effect of theabrownin(TB) extracted from ‘Zijuan’ Pu-erh tea on growth of rats with hyperlipidemia food was studied. The experimental rats were divided into six groups: normal control group, positive control group, hyperlipidemia model group, and low-, medium-, and high-dose theabrownin treatment groups (0.135g/kg, 0.405g/kg, and 1.215g/kg body weight, respectively). The effect of theabrownin extracted from ‘Zijuan’ pu-erh tea on food intake, water intake, body weight and body length, index and pathology section of livers of rats was investigated. After the stage of intervention, TB showed no effect on food intake, water intake, and body length of rats. TB can significantly prevent the increasing of body weight and the fatty degeneration of rat livers with hyperlipidemia food. TB extracted from ‘Zijuan’ Pu-erh tea showed the effect on controlling body weight of hyperlipidemia rats, and it can decrease the fat deposition and prevent the formation of fatty livers of animals, especially with medium and high dose TB(P<0.5).