Journal of Tea Science

Review on Theasinensins in Tea

XU Bin, XUE Jinjin, JIANG Heyuan, ZHANG Jianyong, WANG Yan

Journal of Tea Science. 2014, 34(4): 315-323. doi:10.13305/j.cnki.jts.2014.04.001

Abstract ( 476 )

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Theasinensins (TSs) are produced by oxidation of catechins. Catechins, due to tea rolling, come into and contact with enzymes during tea processing, TSs are generated. The research achievements indicated the physiological function, recently, rising concern of TSs. The article summarized the discovery of TSs, mechanism of TSs formation, analytical method, separation and preparation, pharmacological action.

Simultaneous Determination of 16 Polycyclic Aromatic Hydrocarbons in Dark Tea by HPLC

HU Linling, LIU Zunying, LIU Qiuling, FENG Jinyu, QIN Yu, XIAO Wenjun

Journal of Tea Science. 2014, 34(4): 324-330. doi:10.13305/j.cnki.jts.2014.04.002

Abstract ( 414 )

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A high performance liquid chromatography method that can rapidly detect 16 polycyclic aromatic hydrocarbons in dark tea was established. PAHs were ultrasonic extracted by acetone and methylene dichloride from tea, and purified by silica gel column and eluted with n-hexane. The results showed that the method was satisfactory when the C₁₈ column(4.6 mm×250 mm, 5 μm) was used for HPLC, methyl alcohol and ultrapure water was used for mobile phase, the flow rate was set at 0.6 mL·min^-1, the column temperature was set at 30℃, the UV detection wavelength was set at 274 nm, 16 polycyclic aromatic hydrocarbons can be well separated, the correlation coefficient of 16 PAHs was more than 0.996, detection limit was 0.1-1.0 μg·L^-1, the detection linearity range was 1.0-200.00 μg·L^-1, the recovery of sample with standard was 81.9%-116.5%, the relative standard deviation was less than 2%. The method was characterized by speedily, sensitive, accuracy and low cost, it reduces the requirement for experimental instrument, and can be used for the detection of 16 polycyclic aromatic hydrocarbon in dark tea.

Effect of Benzothiadiazole (BTH) and β-aminobutyric Acid (BABA) on Growth of Tea Shoot and Quality Components

LI Zhenzhen, YANG Yiyang, HU Yunfei, LI Ronglin, LI Xinghui, SONG Fulin, SU Hang, SHI Liang

Journal of Tea Science. 2014, 34(4): 331-336. doi:10.13305/j.cnki.jts.2014.04.003

Abstract ( 492 )

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The effects of different concentrations of BTH and BABA on growth of tea shoot, quality components and metabolic enzyme activity of leaves were investigated. The results showed that, the bud length and weight, water content, amount of dry matter was not significant compared with control (P>0.05). The content of polyphenols, total amino acids, caffeine and soluble protein were increased by 29.32%, 49.10%, 23.77%, 96.34% after 75 mg·L^-1 BTH treatment and 15.75%,45.50%,21.31%,87.18% after 400 mg·L^-1 BABA treatment. And yet, the content of soluble sugar and phenol ammonia ratio decreased. The activity of PPO and GS improved obviously, POD and PAL activity decreased relatively. These preliminary results showed that 75 mg·L^-1 BTH and 400 mg·L^-1 BABA could improve the quality of tea to some extent by adjusting the main components and the activity of related enzymes.

Applied Research on Near-infrared for On-line Rapid Determination of Tea Moisture Content

CHEN Shousong, ZHENG Gongyu, JIN Xinyi, HAO Zhilong, YE Qiuping, LAI Zhilong

Journal of Tea Science. 2014, 34(4): 337-343. doi:10.13305/j.cnki.jts.2014.04.004

Abstract ( 444 )

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Research on an implement method to determinate tea moisture content with rapid non-destructive and on-line technology. Comparing to national standard method, it was proved that the effect of those factors including the dynamic and static state of conveyor belt, spread thickness, measuring height, tea grade on the accuracy of tea moisture content accuracy. The results showed that there were significant differences between CK and different spread thickness and grade, no obvious difference in the treatment of dynamic or static state and measure height. The optimal parameters are that tea conveyor belt speed is 0.8 m·s^-1, conveyor belt should be fully covered by tea samples, and should avoid from the external light irradiate tea samples, spread thickness is (20±5) mm, measure height is (250±50) mm. Different grade of tea set at different measuring channels can be more accurate in measured results.

Analysis on Similarities and Differences of Aromatic Composition in Longjing Teas from Three Producing Regions

ZHANG Xinting, WANG Mengxin, HAN Baoyu

Journal of Tea Science. 2014, 34(4): 344-354. doi:10.13305/j.cnki.jts.2014.04.005

Abstract ( 543 )

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Twelve tea samples were chosen from Xihu producing region, Qiantang producing region, and Yuezhou producing region. Their essential oils were extracted by SDE (Simultaneous Distillation and Extraction) method, and qualitatively and quantitatively analyzed by GC-MS, and combined with the retention time of the authentic standards. In succession, similarities and differences of aromatic composition of them were analyzed by cluster analysis. The results showed that the aroma of Longjing teas from Xihu producing region held the most individual number and the most contents of the aroma compounds within the three producing regions, especially, with abundant typical component linalool, cis-3-hexenyl caproate, β-ionone, nerolidol, benzaldehyde, nonanal, geraniol, cedrol, trans-furanoid linalool oxide. By using the 9 components as variables and 13 tea samples as entities, a cluster analysis was conducted, which divided the 13 tea samples into 2 groups. The 6 tea samples from Xihu producing region clustered together as a group, which still contained one tea sample from Qiantang producing region and Another tea sample from Yuezhou producing region. The other 5 tea samples clustered together as another group. Although Shuangpu Town belonged to Xihu producing region, the aroma of its tea samples were different from those of other 6 tea samples from Xihu producing region. Oblate shaped tea-Jintinglvxue could not be clustered into Xihu producing region group. It was regarded that: (1) Xihu Longjing teas from the original production place held the most individual number and the most abundant contents of aromatic components than those from other producing regions. The aromatic style of Qiantang producing region appeared similarly with that of Yuezhou producing region, in which one or two tea samples were high grade and similar with Xihu Longjing tea, accordingly, included into Xihu Longjing group, the production place of Jingtinglvxue tea was far from that of Xihu Longjing tea, and its aromatic style was obviously different from that of Xihu Longjing tea. (2) the difference among the aroma of Longjing teas from the several roducing regions can be disclosed based on the appropriate parameters and multivariate analysis.

The Ameliorative Effect of L-theanine on Chronic Unpredictable Mild Stress-induced Depression in Rats

PENG Bin, LIU Zhonghua, LIN Yong, LIN Haiyan, HUANG Jian'an

Journal of Tea Science. 2014, 34(4): 355-363. doi:10.13305/j.cnki.jts.2014.04.006

Abstract ( 495 )

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The ameliorative effect of L-theanine on chronic unpredictable mild stress-induced depression in rats and the possible mechanism were investigated. The model of chronic unpredictable mild stress (CUMS) rats was established, and the antidepressant effect of L-theanine was evaluated through sucrose preference test, open-field test and light/dark box test. Then, the contents of the 5-hydroxytryptamine (5-HT), noradrenaline (NA), adrencocorticotropic hormone (ACTH) and corticosterone (CORT) in the hippocampus and prefrontal cortex were determined by ELISA analysis for exploring the underlying mechanism. Also, the enzyme activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) in the serum and hippocampus were measured. The results showed that, compared with control group, the percentage of sucrose preference, the numbers of crossing and rearing, and the number of entries into light box and total duration time in model group were very significantly lower, which demonstrated the model was successfully established. Compared to the model group, the behavior of CUMS-induced depression was significantly ameliorated by the administration of L-theanine, especially that with high dose. Meanwhile, L-theanine could significantly increase the contents of 5-HT and NA, decrease the contents of ACTH and CORT in the hippocampus and prefrontal cortex of rats, increase the activities of SOD and GSH-Px in serum and prefrontal cortex, which further demonstrated the antidepressant function of L-theanine. The underlying mechanism might be mainly related to the enhanced secretion of monoamine neurotransmitter.

Cloning and Expressing Analysis of a Nitrogen Transporter 2.5 Gene from Tea Plant[Camellia sinensis (L.)]

FENG Suhua, WANG Liyuan, CHEN Changsong, LIN Zhenghe, CHENG Hao, WEI Kang, ZHANG Chengcai

Journal of Tea Science. 2014, 34(4): 364-370. doi:10.13305/j.cnki.jts.2014.04.007

Abstract ( 353 )

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The full cDNA length of NRT2.5 gene was obtained via rapid amplification of cDNA ends (RACE) from tea plant [Camellia sinessis (L.)] leaves. The cDNA sequence of this gene was 2 457 bp and opening reading frame (ORF) was 1 362 bp, encoding for 454 amino acids. The putative protein of this gene had an isoelectric point of 9.63 and a calculated molecular weight of 48.7 kD. Bioinformatics analysis showed that NRT2.5 of tea plant was highly homologous to the genes such as TcNRT2.5 and AtNRT2.5, and its encoded protein had the common structural characteristics of NRT family. Fluorescence quantitative real-time PCR analysis showed that NRT2.5 gene were detected in all the tested tissues of tea plant but was mainly detected in the mature leaves and roots. The expression level in different nitrogen concentration showed that the expression of NRT2.5 gene in low N concentration was significant higher than that in high concentration.

Sequencing of Chloroplast Genome of Camellia sinensis and Genetic Relationship for Camellia Plants Based on Chloroplast DNA Sequences

CHEN Chunmei, MA Chunlei, MA Jianqiang, LIU Shengchuan, CHEN Liang

Journal of Tea Science. 2014, 34(4): 371-380. doi:10.13305/j.cnki.jts.2014.04.008

Abstract ( 406 )

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Chloroplast genome sequences have comprehensive application prospects in species identification, phylogeny analyses and transgenic breeding. The complete chloroplast genome of Camellia sinensis cv. Longjing 43 was sequenced using Illumina sequencing technology. The study of genetic relationship for tea plant and its closely related species based on chloroplast DNA sequences trnL-trnF. The results showed that the chloroplast genome of ‘Longjing 43’ was found to be 157 096 bp in length which included a pair of inverted repeats (IRs) of 26 080 bp, separated by a small singlecopy region of 18 283 bp and a large single-copy region (LSC) of 86 653 bp. A total of 133 predicted genes including 86 protein-coding genes, 8 ribosomal RNA genes and 39 tRNA genes were identified. Sequence alignment of trnL-trnF for Plants were selected, the sequence of trnL-trnF ranged from 481 bp to 501 bp in length, the longest length of trnL-trnF region was 501 bp in C. tachangensis, the shortest was 481 bp in C. nitidissima. Phylogenetic analysis showed that all of the Sect. Thea being organized in the same clade. The results will play an important role for tea breeding and phylogenetic relationship study of tea plant and other Camellia species.

Investigation on Guide Vane Motion Model for Cylinder Tea Fixation Machine Based on Logarithm Spiral Line

XU Haiwei, TAN Heping, LI Gang, XIE Chi, LI Jian

Journal of Tea Science. 2014, 34(4): 381-386. doi:10.13305/j.cnki.jts.2014.04.009

Abstract ( 426 )

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Fixation is one of the key processes in green tea manufacturing, and in the cylinder fixation machine, the guide vane has important role on pushing and throwing the fixing tea leaves, which showed a great influence on the tea taste. In this paper, the helix rise angle of guide vane in tea cylinder fixation machine was analyzed based on the logarithm spiral line, which showed great influence on the uniformity of green tea production. The Fluent software is used to do simulations under the fixing leaves heating condition and pushing situation in the cylinder tea fixation machine under the fixed and subsectional design helix rise angles, respectively. With the simulations, the subsectional design structure can effectively improve the green tea quality. This analysis can guide the design in the cylinder fixation machine, to shorten the design cycle, and to improve the design accuracy.

Effects of Green-making Technique on Aroma Pattern of Oolong Tea

CHEN Lin, CHEN Jian, CHEN Quanbin, ZHANG Yinggen, SONG Zhenshuo, WANG Lili, YOU Zhiming

Journal of Tea Science. 2014, 34(4): 387-395. doi:10.13305/j.cnki.jts.2014.04.011

Abstract ( 458 )

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Under controlled indoor air conditions set at (22±1)℃ with relative humidity of (71±4)%, a two-factor experiment, including degree of withering and intensity of rocking, was designed to investigate the effects of green-making technique on aroma characteristics of WIP (work in process) as compared with tea samples prepared during the respective process of Fresh-scent Oolong tea, South Fujian Oolong tea, and North Fujian Oolong tea. Aroma fingerprints of all tea samples were determined by gas chromatography coupled with mass spectrometry and processed with metabolomics analysis platform. The results from cloud plot and principal component analysis indicated that aroma pattern of WIPs would be obviously altered according to weight loss percentage of green leaves, accompanied with the increase on the contents of α-farnesene, benzeneacetaldehyde, geraniol, 3-hexen-1-ol and cis-3-hexenyl hexanoate, and the contents of phytol, indole, butylated hydroxytoluene and ethylbenzene were be decreased accordingly. However, the aromas pertinent to Oolong tea would not be fully formed only combinating on single shaking action with different intensity. Green-making was the essential procedure to bring about special aroma quality of Oolong tea, and the contents of floral scent compositions in tea samples, such as indole, trans-nerolidol, phenylacetaldehyde, etc., could be considered as the most important chemical indicators for quality control, in the green-making process of Oolong tea.

Calculation and Analysis on Mechanism of Winding Grass for Tea Cultivation Machinery

XU Liang

Journal of Tea Science. 2014, 34(4): 396-400. doi:10.13305/j.cnki.jts.2014.04.012

Abstract ( 298 )

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Guizhou is a large tea-producing province, tea garden management cultivation machinery is widely used by tea farmers, and weeding is an important part in tea field management. During field experiment, it was found that winding grass on cultivating machine is a common problem during appliation. This paper conducted on the investigation on the species and length of weed in tea garden of Guizhou province, and analyze the grass winding phenomenon. Through the mechanical analysis and calculation of weed winding, the mathematical model of winding force was established. Based on the analysis of mathematical model, the measures and methods for reducing winding grass are finally concluded.

Research on the Antihyperlipdemic Activity of Theaflavins, Catechins and Saponius Mixture Preparations

ZHANG Cong, TAN Rong, KONG Junhao, GE Qingfeng, YANG Xiufang, WANG Zhijun

Journal of Tea Science. 2014, 34(4): 401-407. doi:10.13305/j.cnki.jts.2014.04.013

Abstract ( 500 )

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The antihyperlipdemic activity in vitro of theaflavins(TFs), catechins(Cs) and saponius(SPs) were assessed in lipid clearance rate in the model of HepG2 steatosis by using the admini stration with 1 mmol·L^-1 oleic acid(OA) in 24 h. Based on the cell viability test(MTT value), lipid clearance was used to evaluate the effect of TFs, Cs and SPs on HepG2 steatosis. The response surface methodology based on a Box-Behnken experimental design was used to optimize the density of the three extractions for combined lipid-lowering in vitro. Results indicated that TFs, Cs and SPs showed a significant inhibitory effect on TG accumulation in HepG2 cells. The ability of lipid-lowering was significant promoted when the three extractions acted on HepG2 at the same time. TFs, Cs and SPs could showed the prevention and curing effect of hyperlipidemia.

Progress on Tea Classification and Discussion on Liupu Tea’s Attribution

WU Ping

Journal of Tea Science. 2014, 34(4): 408-416. doi:10.13305/j.cnki.jts.2014.04.014

Abstract ( 609 )

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By describing the theory and method of tea classification in China and foreign countries, and the special manufacturing technology and the quality characteristic of dark tea, it was regarded that whatever the semi-finished or the finished tea of Liupu tea, both of them were under the process of pilling up and color changing and according with the theory of tea classification, and the related standard and regulation, so could be called as dark tea, according to the investigation on the method of piling up and color changing in the various manufacturing stages of processing process of Liupu tea, the major factors influencing the piling up and color changing and the sensory quality characteristics of semi-finished tea and finished tea. However, the finished tea have received two times of piling up and color changing processes in comparing with the semi-finished tea.

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