Journal of Tea Science

The Physiological Functions of Caffeine and Their Related Mechanisms

WU Ming-yan, FAN Fang-yuan, LIANG Yue-rong, ZHENG Xin-qiang, LU Jian-liang

Journal of Tea Science. 2010, 30(4): 235-242. doi:10.13305/j.cnki.jts.2010.04.001

Abstract ( 1436 )

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Caffeine, one of the most widely consumed psychostimulants and dietary components, showed complicated effects on the nervous system, endocrine system, respiratory and cardiovascular system. It also showed anticarcinogenic activity. However, intake of caffeine may increase the risk of osteoporosis and abortion. Recent advance in the research on caffeine’s physiological functions and their related mechanisms was reviewed in this paper.

Effect of Green Tea on Diabetes

WANG Dong-feng, WANG Lin-ge, ZHANG Li, XU Ying, Bucheli Peter

Journal of Tea Science. 2010, 30(4): 243-250. doi:10.13305/j.cnki.jts.2010.04.002

Abstract ( 547 )

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Diabetes mellitus is a disorder of metabolism and associated with long-term complications that affect eyes, heart, blood vessel, and kidney function. Though oral hypoglycemic agents and insulin are the main prevention and therapy treatment of diabetes, but they have severe side effects and fail to significantly alter the course of diabetic complications. As one of the most popular beverages consumed worldwide, green tea is being widely studied for its health benefits in recent years. In vitro and in vivo studies provide strong evidence that green tea presents a great prophylactic and therapeutic effect against diabetes. This review summarizes the beneficial effects of green tea on diabetes prevention and treatment.

Effects on Aroma Composition of Pu-erh Tea under Solide State Fermentation with Different Beneficial Microorganisms

ZHANG Chun-hua, SHAN Zhi-guo, YUAN Wen-xia, LI Ya-li, SUN Ting-ting, QIN Tai-feng, XIA Kai-guo, REN Hong-tao, LI Guo-rong, ZHOU Hong-jie

Journal of Tea Science. 2010, 30(4): 251-258. doi:10.13305/j.cnki.jts.2010.04.003

Abstract ( 666 )

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The effects of different beneficial microorganism treatments on the aroma components of Pu-erh tea were investigated, the simultaneous distillation and extraction method(SDE) and gas chromatography-mass spectrometry (GC-MS) were used to determine the volatiles in Pu-erh tea. The Pu-erh tea, having been inoculated with several types of beneficial microorganism authorized by the patent (such as Trichoderma viride Pers.ex Fr., Aspergillus niger van Tieghem, Rhizopus arrhizus Fischer, Saccharomyces cerevisiae）Trichoderma viride Pers.ex Fr., Aspergillus niger van Tieghem, Rhizopus arrhizus Fischer, Saccharomyces cerevisiae), was processed under solid state fermentation (SSF). Results shows that, 13 compounds, 53.66% of aroma contents sample were separated and identified from the Pu-erh tea fermented under beneficial fungus of Trichoderma viride Pers.ex Fr. Sample of which the highest contents were terpene-ol compounds and their derivatives. As for the Pu-erh tea fermented by Aspergillus niger van Tieghem fungi, 18 compounds representing 74.77% of aroma contents were separated and identified. In the Pu-erh tea fermented by Rhizopus arrhizus Fischer fungi, 19 compounds representing 54.19% of aroma contents were separated and identified. In the Pu-erh tea fermented by saccharomyces yeast, 19 compounds representing 59.15% of aroma contents were separated and identified. In the Pu-erh tea fermented by Aspergillus niger van Tieghem fungi and Rhizopus arrhizus Fischer fungi, the contents of Methoxy-benzene and its derivatives come out to be highest that 31.24%, 24.04%. In the solid-state fermentation by beneficial fungus of Saccharomyces cerevisiae fungi, the contents of terpene-ol and Methoxy-benzene and its derivatives are higher, up to be 21.89%, 24.07% respectively. Sensory evaluation indicated that the taste of Pu-erh tea sample fermented by Trichoderma viride Pers.ex Fr. was mellow and sweet. Meanwhile, the aroma possesses the fragment of flower and wood. The taste of Pu-erh tea fermented by Aspergillus niger van Tieghem fungi is mellow and the aroma with the fragment of flower and fruits. The taste of Pu-erh tea fermented by Rhizopus arrhizus Fischer fungi, is mellow and smooth, and possesses the strong old fragment. The taste of Pu-erh tea fermented by Saccharomyces cerevisiae fungi, is mellow, sweet and smooth, with quite strong old fragment.

Study on Adsorption Characteristic of Cu(Ⅱ) Ions by Tea Fiber

CUI Xiao-ning, HOU Wei-hua, YANG Xiao-ping, TAN Yang, CAI Jin-xin

Journal of Tea Science. 2010, 30(4): 259-262. doi:10.13305/j.cnki.jts.2010.04.004

Abstract ( 529 )

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The ability of tea fiber to absorb the Cu²⁺ was investigated. The results showed that the optimal pH value and temperature for the adsorption were about 4.55 and 30℃ respectively. When Cu²⁺ initial concentration was 200 mg/L, the adsorption capacity of tea fiber rose first and then decreased with the increase of its addition, and the adsorption capacity reached the maximum with its addition dose of 90 mg. The adsorption process of tea fiber for Cu²⁺ followed a pseudo-second order kinetic equation. The adsorption was more fitted to the Langmuir isotherm equation than the Freundlich isotherm equation. The maximum adsorption capacity was 16.78 mg/g.

Study of the Growth of Eurotium Cristatum Fungi on Some Kinds of Tea and Plant Materials

CAI Zheng-an, LIU Su-chun, LIU Xing-yi, HUANG Jian-an, ZHOU Lin, ZHU Qi

Journal of Tea Science. 2010, 30(4): 263-268. doi:10.13305/j.cnki.jts.2010.04.005

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The growth of Eurotium Cristatum on some kinds of tea and plant materials in simulated processing condition of Fu-brick tea was investigated. Results showed that the Eurotium Cristatum fungi grew very well on different kinds of tea and plant materials without inoculation. It was demonstrated as the Eurotium Cristatum fungi through sensory evaluation and microscopic examination after it was separated and cultivated. The nutrition of Eurotium Cristatum fungi, the pathway spore dissemination, and the possibility in the application and development of multi-function healthy tea were also discussed.

Analysis on the Activity of Tea Pyridoxal Kinase

NIU Tian-tian, ZHANG Jian-yun, HUANG Long-quan

Journal of Tea Science. 2010, 30(4): 269-272. doi:10.13305/j.cnki.jts.2010.04.006

Abstract ( 331 )

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Pyridoxal Kinase (PLK) is the key enzyme in VB₆ metabolism. The crude solution of PLK enzyme was directly extracted from tea plant, after depositing and dialysing with ammonia sulfate by using the phenylhydrazine derivative method to assay the activity of the PLK and its properties. Results showed that the addition of 100%(m/m) PVPP of the fresh tea leaves extraction the PLK could get the best results. The purified tea PLK was enriched by 4.0 fold and its specific activity was 0.737 nmol/(min·mg protein). The requirement of divalent ion for catalysis was mandatory, Zn²⁺was the most efficient ion for catalysis; the optimum temperature and pH of the enzyme were 60℃ and 6.0, respectively. Under optimal conditions, the Km values for pyridoxal and its reactive substrate ATP were 19.3 μmol/L and 53 μmol/L.

Analysis on the Activity of PNPO of VB₆-metabolizing Enzymes from Tea Leaf

LI Yan-xia, ZHANG Jian-yun, HUANG Long-quan

Journal of Tea Science. 2010, 30(4): 273-276. doi:10.13305/j.cnki.jts.2010.04.007

Abstract ( 495 )

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The crude extract of Pyridoxamine (Pyridoxine)-5′-phosphate Oxidase (PNPO) extracted from fresh tea leaves which were grinded by liquid nitrogen with Tris-HCL+ KPO buffer (pH8.5) and fractionated with solid ammonium sulfate, the enzymatic properties were investigated with phenyl hydrazine method. Results showed that when Pyridoxamine phosphate (PMP) as the substrate, the best time for the PNPO oxidation was 30 min, and the optimum pH was 6.5, and the optimum temperature was 50℃. When the value of pH was from 6.0 to 9.0 and temperature was from 10℃ to 40℃, the enzyme was stable. The Km_pmpof the reactive substrate PMP was 2.34 mmol/L under the optimum measure condition.

Structure and Dynamics of Collembola Population in Tea Plantations with Different Habitats

CHEN Li-lin, YOU Min-sheng, CHEN Shao-bo, WU Jia-lin

Journal of Tea Science. 2010, 30(4): 277-286. doi:10.13305/j.cnki.jts.2010.04.008

Abstract ( 510 )

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Collembola is an alternative source of food for natural enemies, a kind of bio-control agent and played an important roles in suppressing pest populations in many agroecosystems. The composition, structure and diversity of the Collembola sampled in the tea canopies or on the ground litters of tea plantations with different habitats on Wuyi Mountains from March 2006 to April 2008 (excluding March 2008) were investigated. In the tea canopies, the species richness (S) of Collembola in the tea plantation intercropped with Paspalum notatum, Cassia rotundifolia or with natural ground cover, and the Shannon-Wiener index (H′) of Collembola in the tea plantation intercropped with C. rotundifolia or with natural ground cover were significantly higher than those on the bare ground. The species abundance (N) of Collembola in the tea plantation intercropped with C. rotundifolia or with natural ground cover was significantly higher than that in the tea plantation intercropped with P. notatum. On the ground litters, the species richness (S), species abundance (N) and absolute abundance ($\bar{n}$) of collembola in the tea plantations intercropped with P. notatum, C. rotundifolia or with natural ground cover were significantly higher than those on the bare ground; the collembola effective diversity index (e^H′) in the the tea plantations intercropped with P. notatum or with natural ground cover was significantly higher than that in the the tea plantations intercropped with C. rotundifolia. The effective diversity index (e^H′), evenness index (E) and absolute abundance ($\bar{n}$) of collembolan in the tea canopies were no significant difference among crop treatments. It also showed no significant difference in the Shannon-Wiener index (H′) and evenness index (E) on the ground litters. The higher similarity of Collembola population was found within the canopies or the ground litters of the four different tea plantations. These findings suggested that rational intercropping may potentially increase the habitat diversity in tea plantations and strengthen the roles of neutral insects in implementation of integrated pest management (IPM) program in tea plantations.

Application of Principal Component Analysis and Cluster Analysis in Evaluation of Color Stability of Tea Beverage

ZHANG Rui-lian, YUAN Hai-bo, YIN Jun-feng, XU Yong-quan, CHEN Jian-xin, WANG Fang, WANG Zhi-lan, YANG Yu-zhou

Journal of Tea Science. 2010, 30(4): 287-294. doi:10.13305/j.cnki.jts.2010.04.009

Abstract ( 607 )

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Principal component analysis (PCA) and Cluster analysis were applied to analyze liquid color stability of tea beverage made from differently processed tea sample. Four principal components generalized from 17 indixes which influence quality stability of tea beverage construct the mathematical evaluation model, and 38 Processes were cluster classified based on the score of comprehensive evaluation. Research showed that, it can be divided into three kinds. The first kind, Z<10, means the liquid color stability of tea beverage is well. The second kind, 10≤Z≤20, means the liquid color stability of tea beverage is common, The third kind, Z>20, means the liquid color stability of tea beverage is bad. It was found after the comprehensive analysis of mathematical evaluation model combined with process type, the dry treatment of raw tea is more important in influencing the stability of tea beverage.

Study on Optimization of Ultrasound-assisted Extraction Technology of Total Flavonoids from Green Tea by Response Surface Methodology

ZHAO Xi, SU Ben-wen, ZHENG Hong-fa, HUANG Huai-sheng, YUAN Ying-fang

Journal of Tea Science. 2010, 30(4): 295-301. doi:10.13305/j.cnki.jts.2010.04.010

Abstract ( 411 )

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In order to optimize the conditions for the ultrasound-extraction technology of total flavonoids from green tea, the Plackett-Burman design was introduced to evaluate the effects of five factors based on single factor test. Ethanol concentration, ratio of liquid to solid and extraction times were found to be the critical for the factors activity of total flavonoids extraction. The optimum conditions for extraction were obtained through Box-Behnken center-united experiment design and Response Surface Methodology with the extraction rate of total flavonoids as the response. The results showed that the optimum extraction conditions are as follows: ethanol concentration 77%, ratio of liquid to solid 42: 1 and extraction times 2. Under the above conditions, the experimental value of extraction rate of total flavonoids is 3.76%, and its predicted value 3.79%, which indicated that the combination of Plackett-Burman design and response surface analysis can well optimize the extractive technology of total flavonoids from green tea.

Study on Anti-influenza Virus Effect of Tea Polyphenols in vitro and in vivo

HUANG Shen-hui, TANG You-zhi, ZHOU Xue-meng, XIE Guo, KURIHARA Hiroshi, HE Zi-hua, CHEN Jian-xin

Journal of Tea Science. 2010, 30(4): 302-308. doi:10.13305/j.cnki.jts.2010.04.011

Abstract ( 435 )

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Tea polyphenols gallocatechin (GC), epicatechin (EC), epigallocatechin (EGC), epicatechin gallate (ECG),epigallocatechin gallate (EGCG), protocatechuic aldehyde (PAD) and protocatechuic acid (PA) were evaluated for their ability to inhibit influenza virus in MDCK cells. Among these compounds, the EGCG and ECG showed a marked antiviral effect against influenza virus infections in MDCK cells and this effect was observed in all influenza virus subtypes tested, including H₅N₁, H₁N₁ and H₉N₂ virus. The 50% effective inhibitory concentrations (EC₅₀) of EGCG and ECG for three virus subtypes were 0.04~0.11 mmol/L and 0.05~0.07 mmol/L, respectively, which were less than the EC₅₀ value of ribavirin(0.41~0.53 mmol/L) in MDCK cells. All these tea polyphenols tested showed an inhibitory effect on the neuraminidases (NAs) from H₅N₁, H₁N₁ and H₉N₂ viruses. The 50% effective inhibitory concentrations (IC₅₀) of EGCG and ECG for three NAs from virus subtypes were 0.03~0.14 mmol/L and 0.34~0.69 mmol/L, respectively. The inhibitory effect of EGCG and ECG on the NAs was similar to their antiviral effect in MDCK cells, which suggested their anti-influenza effect was due to their inhibition on the NAs. In addition, the inhibitory effect on mice infected by influenza virus of extracts from C. assamica var. Kucha containing 85% polyphenolics was evaluated. At the concentration of 1 000 mg/(kg·d), the extracts possessed potent inhibitory effect on BALB/c’s pneumonia consolidation infected by influenza viruses. The inhibition of the extracts on lung index was 37%.

Inhibitory Effects of Sun-dried Green Tea Soup from Different Areas of Yunnan on PTPs Targets

WANG Li-bo, LIANG Ming-zhi, FU Xue-qi, LI You-yong, WANG Ping-sheng, MA Wei, CAI Li, JI Peng-zhang

Journal of Tea Science. 2010, 30(4): 309-312. doi:10.13305/j.cnki.jts.2010.04.012

Abstract ( 432 )

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Using inhibitory rate and IC₅₀ as indexes, the inhibitory effects of sun-dried green tea soup from different areas of Yunnan on 4 targets of PTP1B, SHP-1, SHP-2, HePTP were investigated to compare the functional differences of Pu’erh tea raw materals. Results indicated that the inhibitory effects of different sun-dried green tea were different significantly. Besides, tea cultivar 73-11 sample showed very good inhibitory effect on these four targets, its inhibitory rate and IC₅₀ is >92.0% and <5.5 mg/mL respectively. Based on these conclusions, tea soup of Pu-erh tea’s raw material sun-dried tea possessed different functional effects.

Effects of Green Tea Powder on Immunological Function of Aged Canines

LI Jing, YAN Ze-qing, LI Qun

Journal of Tea Science. 2010, 30(4): 313-316. doi:10.13305/j.cnki.jts.2010.04.013

Abstract ( 415 )

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The aim of experiment was to investigate the effects of different levels of green tea powder on immunological function in aged canines. Seventy two ten year-old aged canines with an average body weight of 34.5~37.5 kg were randomly allocated into 4 groups with 3 replicates of 6 canines, four diets containing green tea powder (0, 1 000, 2 000, 4 000 mg/kg) were given to feed the canine for 9 weeks. The results indicated that containing green tea powder (2 000 mg/kg) group T Lymphocyte Transformation Rate(LTT) reached the highest, increased significantly (P<0.05) up to 47.83%. Although lower adding green tea powder (1 000 mg/kg) reduced serum lysozyme activity in the aged canine, but not significantly (P<0.05), and 2 000 mg/kg and 4 000 mg/kg groups serum lysozyme activity in aged canine were increased obviously (P<0.01). Compared with control the contents of lysozyme in the 2 and 3 treatments increased 32.76% and 19.39% respectively. At the same time, that addition of green tea powder, the total protein(TP) in blood were slightly higher than those in control (P>0.05). When the levels of green tea power increased, the contents of globulin increased. Treatment 3(4 000 mg/kg) were higher than those in the control group(P>0.05).

Effect of Pu-erh Tea on Bone Mineral Densityin Wistar Rats

HOU Yan, XIAO Rong, SHAO Wan-fang, ZHOU Ling, YANG Lan-lan, GONG Jiang, YANG Lei, WANG Guo-cheng

Journal of Tea Science. 2010, 30(4): 317-321. doi:10.13305/j.cnki.jts.2010.04.014

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The effects of Pu-erh tea on the indexes of bone mineral density and bone growth in wistar rats were investigated. 100 male wistar rats were divided into 10 groups of 10 rats each randomly. The first group severed as control. The 9 treatments groups were given daily oral administrations (20 mL/kg) of fermented Pu-erh tea, unfermented Pu-erh tea or green tea tract at the conversation listed above, which yielded dose of 0.5, 1.0 or 2.0 g/kg(body weight). The control group were given oral administrations of distilled water. After 90 d of treatment, the rats were sacrificed, peeled left femur and the weight of femur, the content of calcium and phosphorus in bone, the density of bones etc were determined. The resulted showed that compared to the control group, the weight of left femur in groups treated with either low, medium dose of unfermented Pu-erh tea and green tea or each dose of fermented Pu-erh tea was not statistically signification(P>0.05). The content of calcium in bone in groups treated with either the highest dose of unfermented Pu-erh tea and green tea or low, median dose of fermented Pu-erh tea was significantly higher than the control group(P<0.05) while the content of phosphorus in each group was significantly higher than the control group(P<0.05). The density of each group of fermented and unfermented Pu-erh tea and green tea was not statistically signification(P>0.05). Under the experimental conditions, these tea did not affect bone mineral density of rats.

The Measurement on TBT of the Sino-Japan Green Tea Trade

JIANG Tao, QIN Qiong-xia

Journal of Tea Science. 2010, 30(4): 322-327. doi:10.13305/j.cnki.jts.2010.04.015

Abstract ( 449 )

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The value of Technology Trade Barrier(TBT) in Sino-Japan green tea trade was gauged by the method of tariff-equivalent and wedge model. Based on the individual decision, The family utility function was used to estimate the Japanese consumer preference of different green tea. And then by the data on Sino-Japan green tea trade and Japan domestic month statistics, the value of the corresponding trade tariffs equivalence was gotten.

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