Journal of Tea Science

Advances in Research on the Regulation of Tea Polyphenols and Effects on Intestinal Flora

ZHOU Fang, OUYANG Jian, HUANG Jian'an, LIU Zhonghua

Journal of Tea Science. 2019, 39(6): 619-630. doi:10.13305/j.cnki.jts.2019.06.001

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Metabolic syndrome (MS) is an abnormal multi-metabolic disease that comprises a combination of various diseases such as hypertension, abnormal blood sugar, dyslipidemia and obesity. Tea polyphenols (TPs) are the characteristics secondary metabolites in tea leaves. The latest studies show that TPs can improve the disorder of gut flora (GF) and modulate the co-metabolism of Host-GF by the intervention & treatment to achieve the goal of improving MS. This paper systematically summarized the absorption and metabolism of TPs and the effects of TPs on GF in in vitro fermentation models, animal experiments, and clinical trials. The underlying mechanism among TPs-GF-Host was described, which would facilitate further exploring the effects of TPs on human health based on the theory of intestinal flora and developing functional products of TPs. In addition, it also provided theoretical foundation for developing functional products associating with TPs.

Protective Effect of Fu Brick Tea on Intestinal Mucosal Barrier and Liver Injury in NAFLD Rats

ZUO Gaolong, CHEN Meiyan, LIN Yong, LIN Haiyan, LIU Zhonghua, WU Wenliang

Journal of Tea Science. 2019, 39(6): 631-640. doi:10.13305/j.cnki.jts.2019.06.002

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To explore the protective effect of Fu brick tea on intestinal mucosal barrier and liver injury in rats with high-fat induced non-alcoholic fatty liver disease (NAFLD). SD male rats were randomly divided into normal, NAFLD, low-dose and high-dose Fu brick tea groups, 8 rats each group. The establishment of NAFLD rat model and the intervention effect of Fu brick tea were evaluated by analyzing the feed intake, weight change, blood lipid index, liver index and pathological section of rats. Intestinal integrity and intestinal permeability was assessed by pathological and PAS staining sections of jejunum and colon, villus height/crypt depth (V/C value) serum diamine oxidase (DAO) activity and lipopolysaccharide (LPS) activity. Intestinal-related inflammation was assessed by the number of jejunum intraepithelial lymphocytes (JIL) and the activity of serum tumor necrosis factor-alpha (TNF-α). The results show that Fu brick tea could reduce the feed intake andbody weight of NAFLD rats, decrease blood lipid levels, reduce the activity of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in serum, and inhibit lipid accumulation and inflammation in the liver. Fu brick tea also reduced the levels of serum inflammatory factors TNF-α and serum LPS and increased the activity of serum DAO. Moreover, Fu brick tea inhibited inflammatory cell infiltration in jejunum and colon villi of NAFLD rats, reduced the jejunum villus shedding, fracture, sparse and disorder, increased the jejunum villus V/C value, and decreased the number of jejunum intraepithelial lymphocytes, and increased the number of goblet cells in the jejunum and colon. These data indicate that Fu brick tea could effectively improve the intestinal mucosal barrier and liver injury induced by high-fat diet, which could be used to prevent and treat NAFLD.

Protective Effects of Fu Brick Tea Extracts on Inflammatory Bowel Disease Induced by Dextran Sulfate Sodium in Mice

HU Ankai, YAO Liyun, ZHAO Yueling, LIU Chang, WANG Yuefei, XU Ping

Journal of Tea Science. 2019, 39(6): 641-651. doi:10.13305/j.cnki.jts.2019.06.003

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Fu brick tea is a special dark tea in China. In the present work, three extracts, including Fu brick tea water extract (FWE), Fu brick tea ethanol soluble fraction (FES) and Fu brick tea ethanol precipitation fraction(FEP), were prepared and used to further explore their protective effects on inflammatory bowel disease in mice. Researches show that all the Fu brick tea extracts could alleviate the intestinal structure damage of IBD mice. Moreover, the extracts increased the activities of SOD, CAT and the levels of GSH and reduced the levels of IL-6, IL-1β, TNF-α in serum and colon tissue supernatant of mice. Furthermore, the protein level of NF-κB p65 in the colon tissues in the FWE group was decreased compared to the model group. The protein level of IκBα was increased in the FWE group and FES group. Levels of Nrf2 and HO-1 were also increased in the FWE and FES groups. In conclusion, Fu brick tea extracts had a protective effect on IBD mice induced by DSS.

Comparative Study on the Structure and Hypoglycemic Activity of Several Tea Polysaccharides

LIU Danqi, REN Fazheng, LI Jingming, HOU Caiyun

Journal of Tea Science. 2019, 39(6): 652-660. doi:10.13305/j.cnki.jts.2019.06.004

Abstract ( 938 )

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To study and compare the composition, blood sugar lowering effect and composition of WTP, GTP and BTP. Shoumei, Longjing and Bailingongfu were selected as representatives of white tea, green tea and black tea, and the composition, molecular weight of tea polysaccharides were determined. The mice diabetes model was induced by streptozotocin, metformin was used as a positive control to study the hypoglycemic effect of tea polysaccharides, and qPCR was used to determine the expression level of related genes in mice liver. The results showed that the molecular weights of WTP, GTP and BTP are 18 180 Da, 19 470 Da and 8 745 Da, respectively. The selected tea polysaccharides have hypoglycemic effect, the fasting blood glucose decline rates of WTP, GTP and BTP were 53.2%, 52.8% and 61.6%, respectively. Tea polysaccharides can all improve glucose tolerance, down-regulate the expression of Foxo1, G6Pc, PEPCK and TXNIP genes in mice and there are some differences.

Identification and Pathogenicity Analysis of Pathogens in Tea Branches

ZHANG Lan, GUO Huawei, LI Menghan, LIAO-YANG Wenke, LI Xin, HAN Wenyan

Journal of Tea Science. 2019, 39(6): 661-668. doi:10.13305/j.cnki.jts.2019.06.005

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The pathogens of diseased tea branches in tea garden of Datong town, Jiande city were identified by morphological and molecular methods. Two fungal pathogens were identified, namely Fusarium incarnatum and Colletotrichum fructicola. F. incarnatum here was reported as the pathogen of tea trees. Leaves and stems of Longjing43 and Zhongcha108 were used in the experiment to analyze the pathogenicity of the two pathogens. The results show that F. incarnatum had strong pathogenicity to young leaves and stems of Longjing43, indicating it is the main pathogen causing relative disease. F. incarnatum and C. fructicola might infect tea leaves together which needs more attention in tea disease recognition, control and prevention in future.

Cloning and Expression Analysis of Serine Protease EoSP1 in Tea Geometrid (Ectropis obliqua) and Its Response to Starvation

ZHANG Xin, Chen Chengcong, DU Qin, LI Xiwang, SUN Xiaoling

Journal of Tea Science. 2019, 39(6): 669-680. doi:10.13305/j.cnki.jts.2019.06.006

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Serine protease plays an important role in the digestion process of Lepidoptera insects. In this study, we cloned a serine protease encoding gene EoSP1 from Ectropis obliqua and analyzed its basic characteristics and expression patterns. The coding sequence of EoSP1 is 858 bp, encoding 285 amino acid residues with deduced molecular weight of 29.53 kDa and isoelectric point of 5.44. Compared with other serine proteases, EoSP1 contains conserved serine protease catalytic sites (H₉₅, A₁₆₁ and S₃₂₈) and protein interaction domains, and shows the closest relationship with SPs from Mamestra configurata. Further, EoSP1-GST fusion protein similar to the predicted size was purified from E. coli cells. qRT-PCR analysis showed that the expression level of EoSP1 was much higher in larvae than that in adults, pupae and eggs, and expressed in midgut of larvae specifically. EoSP1 was down-regulated by starvation treatment, and the expression level was change back to that of control group after re-feeding. The above results provide a basis for the function analysis of digestive enzyme and screening of new insect-resistance targets in Ectropis obliqua.

Screening of miRNA Related to Anthocyanin Synthesis in Tea Cultivar ‘Zijuan’ Based on High Throughput Sequencing

CHEN Linbo, XIA Lifei, LIU Yue, SUN Yunnan, JIANG Huibing, TIAN Yiping, CHEN Liang

Journal of Tea Science. 2019, 39(6): 681-691. doi:10.13305/j.cnki.jts.2019.06.007

Abstract ( 773 )

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In order to screen the miRNAs related to anthocyanin synthesis in 'Zijuan', the miRNA library was constructed by using the tea cultivars 'Zijuan' (ZJ), 'Yunkang 10' (YK) and 'Fuding Dabaicha' (FD). In this study, 46 known miRNAs and 67 unknown miRNAs were identified, and 765 annotated target genes were predicted. A total of 24 miRNAs were screened out, which were differentially expressed between ZJ and YK, and between ZJ and FD. Four target miRNAs involved in the regulation of anthocyanin synthesis, namely miR828a, miR845c, novel_14 and novel_87, were identified by target gene analysis of 24 differentially expressed miRNAs. The predicted target genes include transcription factor genes MYB4, MYB23, MYB26, MYB82, bHLH74 and 4CL (4-coincyl-CoA-linked enzyme), DFR (dihydroflavonol 4-reductase) and UFGT (UDP-glucoside flavonoid 3-O-glucosyltransferase). Eight differentially expressed miRNAs were analyzed by RT-PCR and the results were consistent with transcriptome analysis. Finally, a theoretical basis for further study of regulation mechanisms related to anthocyanin biosynthesis in tea plant was provided.

Aroma Profiling of Oolong Tea by SDE and HS-SPME in Combination with GC-MS

CHEN Lin, YU Wenquan, ZHANG Yinggen, XIANG Lihui, WANG Lili, YOU Zhiming

Journal of Tea Science. 2019, 39(6): 692-704. doi:10.13305/j.cnki.jts.2019.06.008

Abstract ( 967 )

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To better understand the aroma characteristics of oolong tea, the volatile compounds of three representative Fujian oolong tea samples (Tieguanyin, Rougui and Shuixian) were isolated by simultaneous distillation-extraction (SDE) and head space solids-phase microextraction (HS-SPME) coupled with three different fiber coatings, and analyzed by gas chromatography-mass spectrometry (GC-MS). 262 aroma components were detected by different extraction methods. The number of aroma components detected from high to low was 204 (Rougui), 175 (Shuixian), and 120 (Tieguanyin), respectively. HS-SPME with dry samples were detected with 186 aroma components, followed by HS-SPME with wet samples (139), and SDE method detected 33 aroma components. Different extraction methods can complement each other on the detection of aroma components. A 65βμm PDMS/DVB (Polydimethylsiloxane/Divinylbenzene) fiber showed good reproducibility, and some common or characteristic aroma components in oolong tea samples were robustly detected, such as nerolidol, indole, alpha-farnesene, phenylethyl alcohol, benzyl nitrile, methyl salicylate, etc. Compared with Tieguanyin, Rougui and Shuixian had higher number of aroma components, and the aroma compositions of Rougui were the most complex. These results were in consistent with the sensory evaluation of oolong tea produced from north and south of Fujian province, and Rougui showed higher aroma quality than that of Shuixian.

Research on Main Physical Properties of Tea Leaves in High-quality Green Tea Processing

LI Chen, AI Zeyi, YU Zhi, CHEN Yuqiong, NI Dejiang

Journal of Tea Science. 2019, 39(6): 705-714. doi:10.13305/j.cnki.jts.2019.06.009

Abstract ( 1049 )

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Taking one bud and one bud with one leaf of tea as the test materials, the variations of physical properties of tea leaves such as bulk density, texture and tensile properties in needle-shaped green tea processing were studied by the method of constant weight and graduated cylinder, TPA and stress-strain tensile test. As a result, the bulk density of tea leaves was first increased and then decreased, with the peak in the rolled leaves (water content 56%-58%). it was sharply decreased during the post-forming, fixing and drying processes. The plasticity presented the same trend with the maximum appeared in the rolling process. It then remained a high level in the forming process (water content 58%-23%), and declined significantly during the fixing and drying processes. The trend of elasticity was opposite to the plasticity, with the lowest level in the rolling and forming processes (water content 58%-23%). Less variation was observed in flexibility during the whole processing. The tensile process of tea leaves undergoed linear, nonlinear and plastic deformation to fracture stages. The trend of maximum force was decreased first and then increased (water content 56%-57%). The tensile strength was increased during the whole processing. The elastic modulus varied a little before the rolling process and then increased significantly. The correlation analysis shows that the tensile strength of tea leaves was significantly and negatively correlated with water content in the processing, and the diversification of main physical properties of one bud and one bud with one leaf in processing were not exactly the same. Besides the similar level of plasticity and flexibility, the bulk density, elasticity and maximum force of one bud were higher than that of one bud with one leaf. While the plasticity, tensile strength and elastic modulus showed an opposite trend. In the whole processing, apart from the similar level of plasticity and flexibility, the bulk density and elasticity of one bud in each process were higher than that of one bud with one leaf, but the elastic modulus and tensile strength showed an opposite trend. the maximum force of one bud with one leaf was significantly higher than that of one bud after the rolling process. In conclusion, the differences in raw materials should be emphasized in the principles of mechanical design and processing techniques.

Nonlinear Manifold Dimensionality Reduction Methods for Quick Discrimination of Tea at Different Altitude by Near Infrared Spectroscopy

LIU Peng, AI Shirong, YANG Puxiang, LI Wenjin, XIONG Aihua, TONG Yang, HU Xiao, WU Ruimei

Journal of Tea Science. 2019, 39(6): 715-722. doi:10.13305/j.cnki.jts.2019.06.010

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In order to improve the accuracy of near infrared (NIR) spectroscopy identification methods for tea at different altitude, the non-linear manifold dimensionality reduction methods of locally linear embedding (LLE) and laplacian eigenmaps (LE) were used to reduce the dimension of NIR spectral data, and compared with non-linear (KPCA) and linear (PCA) dimensional reduction methods. Discrimination models were established for tea at different altitude based on different dimensional reduction methods and least squares support vector machine (LSSVM) algorithm. Visualization of different dimensionality reduction results show that data processed by KPCA and PCA methods were more discrete. In particular, there were more overlaps between 400-800 m and 800-1 200 m samples. However, the same kind of sample points could be gathered well in three-dimensional space by the nonlinear manifold dimensionality reduction methods can. Tea at different altitude could be easily separated and the aggregation effect of the LE was better than that of the LLE. The results of models indicate the LE_LSSVM model had the best performance, with the prediction set accuracy and Kappa value of 100% and 1.00 respectively. Compared with PCA_LSSVM, KPCA_LSSVM and LLE_LSSVM models, the accuracy of prediction set was improved by 1.7%, 1.7%, 3.3% and Kappa values increased by 0.025, 0.03, and 0.05. The results show that LE and other nonlinear manifold dimensionality reduction methods were effective in reducing dimension of near infrared spectral data, simplifying model complexity, and improving model precision. The study provides a new means for rapid detecting for tea quality research.

The Role of Plasma Membrane H⁺-ATPase on Nitrogen-regulated Phosphorus Uptake in Tea Plants

CHEN Linmu, CHEN Jingguang, WANG Ningning, ZHANG Xianchen

Journal of Tea Science. 2019, 39(6): 723-730. doi:10.13305/j.cnki.jts.2019.06.011

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Phosphorus is one of the most important mineral elements for plant growth and development, and different nitrogen forms can regulate phosphorus uptake. As is well-known that plant plasma membrane (PM) H⁺-ATPase plays an important role in nutrition uptake, it may also relate to the different nitrogen-modulated phosphorus uptake. In our study, PM H⁺-ATPase in tea roots were isolated by two-phase partitioning in aqueous dextranT-500 and polyethylene glycol, and the effect of different nitrogen forms on phosphorus uptake and the characteristic parameters of PM H⁺-ATPase in tea roots were examined by using non-invasive micro-test technique and Western-blot. It was found that ammonium significantly improved the phosphorus accumulation in tea plants as compared with nitrate nutrition. In addition, less depolarized PM potentials, higher net H⁺ flux, PM H⁺-ATPase activities and protein levels were found under ammonium treatment than those under nitrate nutrition treatment. Furthermore, vanadate (the PM H⁺-ATPase inhibitor) significantly decreased phosphorus accumulation in tea plants under ammonium and nitrate nutrition treatments, which further suggests that PM H⁺-ATPase may be involved in phosphorus accumulation in tea plants regulated by different nitrogen forms.

Characteristics of Soil Nitrification Potential in Different Tea Gardens of China

NIU Siyun, NI Kang, ZHAO Chenguang, MA Lifeng, RUAN Jianyun

Journal of Tea Science. 2019, 39(6): 731-741. doi:10.13305/j.cnki.jts.2019.06.012

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In order to characterize the nitrification activities of tea plantation soils in different areas, totally 30 typical soil samples from 12 provinces were collected. The soil nitrification potential was determined by using the shaken-soil-slurry method. The multiple regression analysis and partial least squares regression (PLS) were carried out to characterize the main impact factors. The nitrification potential in tea plantation soils ranged from 0.24 to 5.31 mg·kg^-1·h^-1, and the abundance of AOA in soil was significantly higher than that of AOB. Both AOA and AOB showed significantly positive correlation with soil nitrification potential. Abundance of ammonia oxidation microbes, C/N, nitrate, ammonium, total nitrogen and organic carbon contents were the significant important factors influencing nitrification potential, with a descending order of importance according to PLS. These results reveal that nitrification potential is still high in tea plantation soil, since AOA dominate the ammonia oxidation process. The difference of ammonia-oxidizing microorganisms, availability of soil carbon, nitrogen caused by climate, soil conditions and fertilization regimes are likely to be the main factors for the variation of the nitrification potential in tea plantation soils.

Research and System Design of Tea Processing Remote Cloud Monitoring and Traceability

JIANG Jiandong, ZHOU Qian, PAN Bosong, ZHAO Zhangfeng, ZHONG Jiang, QIAO Xin, ZHANG Xian

Journal of Tea Science. 2019, 39(6): 742-752. doi:10.13305/j.cnki.jts.2019.06.013

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In view of the remote monitoring demand of tea processing and the lack of tea processing traceability, a remote IoT （Internet of things） monitoring platform for state parameters during tea processing was proposed. It achieved the remote monitoring of both processing line and tea state. A traceability evaluation model of tea processing was established by using B/S framework to show real-time information, combined data of both fresh leaf states and tracing information of processing, and analytic hierarchy process to analyze the effects of production parameters on tea quality. On this basis, the quality evaluation model of tea production offline and online database fusion was constructed to improve the quality of data storage. Finally, the remote monitoring system development and traceability information collection verification test were carried out for the Huangshan Maofeng preliminary processing production line. The results show that the platform is stable, the data display is accurate and complete, and the real-time performance is good, which provides technical support for tea quality optimization and big data analysis.

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