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Research Progress on Colored Substances in Tea LONG Piaopiao, SU Shengxiao, ZHANG Liang Journal of Tea Science    2023, 43 (5): 593-606.   DOI: 10.13305/j.cnki.jts.2023.05.010 Abstract （378）      PDF（pc） （733KB）（377）       Knowledge map    Save The color of tea leaves and infusions is an important attribute to tea flavor and quality. Colored substances contain chromophore and auxochrome groups, which contribute to producing different shades of green, yellow, and red hue in tea infusion. As the concentrations of colored substances increase, the tea infusions’ color will increase accordingly, presenting different colors such as yellowish-green, reddish-yellow and reddish-brown. Furthermore, fermentation (enzymatic oxidation) and drying stages during processing, as well as temperature, pH, and concentration in sensory evaluation, affect the color and brightness of tea infusions. This review revealed the color formation mechanisms by summarizing the chemical structures, color characteristics, coloration mechanisms and other factors of color substances in tea. It also provided a theoretical evidence for the quality improvement of tea flavor and the innovation of processing technology. Reference | Related Articles | Metrics

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Analysis of Aroma Characteristics and Volatile Components of Zhenghe White Tea with Different Storage Years HUANG Wei, ZHANG Lingzhi, ZHANG Jialin, LIN Fuming, RONG Jiefeng, XIAO Chunyan, YUE Penghang, YU Huazhu, SUN Weijiang, HUANG Yan Journal of Tea Science    2023, 43 (5): 667-680.   DOI: 10.13305/j.cnki.jts.2023.05.006 Abstract （277）      PDF（pc） （1492KB）（314）       Knowledge map    Save In order to investigate the aroma characteristics of Zhenghe white tea with different storage years, quantitative descriptive analysis (QDA) combined with headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used to analyze the aroma characteristics and volatile components of Zhenghe white peony tea stored for 0, 5, 10 and 15 years. The results show that the aroma characteristics of Zhenghe white peony tea varied significantly among different storage years. The aroma characteristics of BMD0 were mainly pekoe, fresh, sweet and floral. With the extension of storage time, the pekoe, fresh, sweet and floral weakened, while the stale flavour and woody increased. A total of 66 volatile components were detected in Zhenghe white peony tea with different storage years, mainly alcohols, esters and acids, with the highest alcohol content in BMD0 and BMD5, and the highest ester content in BMD10 and BMD15. With the extension of storage time, the total volatile components decreased significantly, and the composition and proportion of relative contents changed significantly. The Orthogonal partial least-squares discrimination analysis (OPLS-DA) model could effectively discriminate Zhenghe white peony tea with different storage years. A total of 14 volatile components were screened based on relative odor activity value (rOAV)>1, while 30 volatile components were screened based on variable importance for the projection (VIP)>1. Based on rOAV value>1 and VIP value>1, 6 major volatile components were screened, including β-ionone, α-ionone, nerolidol, benzyl alcohol, benzeneacetaldehyde, linolenic acid. This study provided a theoretical reference and basis for the scientific storage of white tea and the flavour analysis of aged white tea. Reference | Related Articles | Metrics

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Present Status and Development Trends of Research on Tea Polysaccharides LI Yan, LIN Yongfeng, LIU Wenmei, ZOU Zehua, LIU Guangming, LIU Qingmei Journal of Tea Science    2023, 43 (4): 447-459.   DOI: 10.13305/j.cnki.jts.2023.04.001 Abstract （264）      PDF（pc） （475KB）（479）       Knowledge map    Save Tea polysaccharides are important active ingredients in tea. Studying the properties of tea polysaccharides and promoting the development of tea polysaccharides products will benefit both the tea industry and the health industry. In the present paper, literatures related to tea polysaccharides from the Web of Science database over the past decade were visually analyzed. The results show that the overall number of papers related to tea polysaccharides showed an increasing trend from 2013 to 2022. The co-occurrence, emergence and frequency analysis of keywords show that the antioxidant activities of tea polysaccharides are a continuous research hotspot, which may also be one of the main trends in future research. At present, global research on tea polysaccharides mainly focuses on the physicochemical properties including monosaccharide composition, solubility, emulsification and biological activities such as antioxidation, anticancer and antidiabetic. Although tea polysaccharides exhibit a variety of biological activities, the underlying mechanisms are still not well understood. Recent studies have shown that tea polysaccharides can exert probiotic potential by affecting gut microbiota. In addition, the transformation and development of tea polysaccharide-related products are particularly insufficient. In the future, researchers can focus on developing biofilm products, drug delivery vehicles and functional foods using tea polysaccharides. Overall, the present paper summarized the main contents and hot spots in the field of tea polysaccharides, aiming to serve as a reference for researchers in this field as well as for the development of the tea polysaccharide industry. Reference | Related Articles | Metrics

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Construction of Flavor Wheel and Quantitative Sensory Description Analysis of Pu'er Tea and Fu Brick Tea CHEN Guohe, HU Tengfei, XIE He, FU Wenjie, ZHAI Yuke, BAO Sudou, AN Qin, WANG Chao, WANG Yingzi, LIU Zhonghua, HUANG Jian'an Journal of Tea Science    2023, 43 (5): 631-644.   DOI: 10.13305/j.cnki.jts.2023.05.008 Abstract （241）      PDF（pc） （1988KB）（233）       Knowledge map    Save Flavor wheel is a simple and easy method to understand descriptor system, which is convenient for consumers to communicate the sensory flavor attributes of Pu'er tea and Fu brick tea. In this study, by establishing a sensory evaluation team, sensory evaluation was conducted on the flavor of Pu'er tea and Fu brick tea, and the flavor wheels of Pu'er tea and Fu brick tea were drawn from two dimensions: aroma and taste. On this basis, a vocabulary for quantitative sensory description of Pu'er tea and Fu brick tea was established by setting reference samples with different intensities for 23 typical sensory descriptions. Furthermore, using the M-value method combined with analysis of variance and multivariate statistical analysis, the main sensory descriptors that can better describe Pu'er tea and Fu brick tea were selected. A total of 7 aroma descriptors (woody, sweet aroma, herbal, ferment, glutinous, jujube and aged) and 5 flavor descriptors (sweet taste, bitter, astringent, sour and mellow and thick) were selected for Pu'er tea, and 5 aroma descriptors (woody, sweet aroma, herbal, aged and fungal floral) and 5 flavor descriptors (sweet taste, bitter, astringent, sour and mellow and thick) were identified for Fu brick tea, and these descriptors can better evaluate the sensory quality characteristics of Pu'er tea and Fu brick tea samples. The results of this study provide application value for distinguishing and evaluating the sensory flavor characteristics of Pu'er tea and Fu brick tea, as well as in the development of their products. Reference | Related Articles | Metrics

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Analysis of Codon Usage Bias and Phylogenesis in the Chloroplast Genome of Ancient Tea Tree Camellia taliensis in Forest-tea Garden TONG Yan, HUANG Hui, WANG Yuhua Journal of Tea Science    2023, 43 (3): 297-309.   DOI: 10.13305/j.cnki.jts.2023.03.010 Abstract （227）      PDF（pc） （571KB）（227）       Knowledge map    Save Camellia taliensis is one of the important tea plants which is often grown in forest-tea gardens, which participated in the origin and domestication of C. sinensis var. assamica. To determine the codon usage bias pattern and its main influencing factors in the chloroplast genome of C. taliensis, neutral plotting, ENC-plot, PR2-plot analyses were performed and the optimal codons were found. The results show that the GC content of 54 CDS sequences was 37.68%, while GC1 and GC2 content were 46.44% and 39.77%, higher than GC3 (27.67%), indicating that the third base of the codon preferred to end in A/U. The effective codon number (ENC) ranged from 35.64 to 56.67 , with an average value of 46.1, demonstrating weak codon usage bias in chloroplast genome of C. taliensis. Neutral plotting, ENC-plot, PR2-plot analyses show that the main factor affecting the codon usage bias of the C. taliensis chloroplast genome was natural selection. In total, 11 optimal codons were identified in the chloroplast genome of C. taliensis. Although phylogenetic trees constructed by matK gene and CDS sequence display different topological structures, all trees show that C. taliensis and C. gymnogyna are clustered into one branch and are closely related to cultivated tea plant. This study provided the basis for analyses of genetic evolution, phylogeny and improved agronomic traits of C. taliensis. Reference | Related Articles | Metrics

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Ecological Thoughts in Ancient Chinese Tea Books and Their Contemporary Value LIU Xinqiu, DU Xiya Journal of Tea Science    2023, 43 (3): 437-446.   DOI: 10.13305/j.cnki.jts.2023.03.013 Abstract （218）      PDF（pc） （362KB）（213）       Knowledge map    Save Chinese traditional ecological thoughts with the core of Confucianism, Buddhism, Taoism culture, in the pursuit of harmony in the process of human and nature, are consisted of a series of environmental protection and respect for life. It is formed by the particular geographical environment, political status, economic conditions and cultural factors, which thereby formed an agriculture production system of intensive cultivation. Under the influence of the ecological thoughts, a special system of tea planting management and tea drinking methods has been established in the production and development of tea industry, which was mostly recorded in the tea books of all dynasties. The ecological thoughts of tea industry were embodied in different periods, including the historical understanding of tea planting ecological environment, the development and evolution of tea garden management technologies and the stage change of tea drinking mode. The ecological concept of ancient tea industry has been inherited and can still be used for reference and implementation today. Reference | Related Articles | Metrics

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Advances in the Application of Metabolomics in the Study of Physiological and Biochemical Metabolism of Tea Plants [Camellia sinensis (L.) O. Kuntze] MAO Chun, HE Ji, WEN Xuefeng, WU Chuanmei, YI Chengxi, LIAN Jianhong, GUO Wenmin Journal of Tea Science    2023, 43 (5): 607-620.   DOI: 10.13305/j.cnki.jts.2023.05.009 Abstract （215）      PDF（pc） （477KB）（334）       Knowledge map    Save Tea is a leafy perennial crop, and its physiological metabolism is significantly affected by external environmental factors. Main biochemical components such as amino acids, caffeine and tea polyphenols not only give tea unique flavor quality and health characteristics, but also are important contributors to the resistance of tea plants to biotic and abiotic stresses. Metabolomics technologies have the characteristics of high throughput, high sensitivity and systematization. They can identify and quantify tea metabolites comprehensively, accurately and quickly. The in-depth study of metabolomics provides a technical platform for the further development and utilization of tea metabolites. This paper reviewed the applications of metabolomics in the study of physiological and biochemical metabolism (photosynthesis, respiration, carbon and nitrogen metabolism) and metabolism of main quality biochemical components (flavonoids, alkaloids, amino acids, etc.) of tea plants in recent years, and prospected the future applications of metabolomics in the field of tea, so as to provide some theoretical references for further tea management, cultivar breeding and quality improvement. Reference | Related Articles | Metrics

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Research Progress of Quantitative Evaluation Methods for Tea Grade ZOU Dan, YIN Xiaoli, GU Huiwen, LONG Wanjun, FU Haiyan, SHE Yuanbin Journal of Tea Science    2023, 43 (6): 733-746.   DOI: 10.13305/j.cnki.jts.2023.06.011 Abstract （205）      PDF（pc） （2029KB）（192）       Knowledge map    Save Grade is an important indicator for discerning the quality of green tea and other types of tea, and it is directly related to their selling prices. However, there is often a phenomenon of falsely labeling tea grades in the market, which seriously undermines consumer rights. At present, tea grade is mainly assessed by sensory evaluation. Sensory evaluation, after long-term development, has formed relatively unified standard, but it still has a certain subjectivity. To evaluate the tea grade more accurately and objectively, researchers have developed a series of quantitative evaluation methods for tea grade. Given the significant practical importance of evaluating tea grade, this article provided a comprehensive review of the recent research status in the qualitative and quantitative evaluation of tea grades, including bionic sensing intelligent sensory detection technology, specific chemical components detection and metabolomics techniques. Major problems and challenges on tea grade evaluation were discussed, and future development trend was also prospected in this study. It has positive guiding significance for objective, scientific and standardized evaluation and quality control of tea quality. Reference | Related Articles | Metrics

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Changes of Endogenous Hormone Contents and Expression Analysis of Related Genes in Leaves of Tea Plants Under Heat and Drought Stresses TANG Ziyi, DU Yue, YANG Hongbin, LI Xinghui, YU Youben, WANG Weidong Journal of Tea Science    2023, 43 (4): 489-500.   DOI: 10.13305/j.cnki.jts.2023.04.006 Abstract （200）      PDF（pc） （1970KB）（221）       Knowledge map    Save Extreme environments, such as heat and drought, seriously affect the growth and development of tea plants and the quality of tea production. Hormones are important signaling factors, but the molecular mechanisms of hormones involved in the response of tea plants to heat and drought stresses are rarely reported. In this study, we systematically analyzed the changes in endogenous hormone contents and the expression levels of related genes in leaves of tea plants under heat and drought stresses. The results show that the contents of IAA and GA3 were significantly reduced and the contents of ZR were slightly increased in leaves of tea plants under heat and drought stresses, which were presumably used to delay the growth of tea plants to adapt to the environment stresses. Meanwhile, many genes related to biosynthesis and signal response of IAA, GA3 and ZR were significantly differentially expressed, which provided a molecular basis for explaining the hormone content changes and signal transduction. In addition, the contents of ABA and JA increased significantly under both heat and drought stresses, which may depend on the up-regulated expressions of ABA biosynthetic pathway genes such as ZEP, NCED, SDR and JA biosynthetic pathway genes such as LOX, OPR, ACX. Furthermore, many ABA signal responsive genes such as PYR/PYL, PP2C and JA signal responsive genes such as JAZ, MYC2 were also significantly differentially expressed, suggesting the important role of ABA and JA signaling pathways in the response of tea plants to heat and drought stresses. These results provided theoretical references for further exploring the molecular mechanisms of tea plants response to heat and drought stresses, which rely on endogenous hormones. Reference | Related Articles | Metrics

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Identification of Transcription Factors Interacting with CsNCED2 Promoter and Their Response to Abiotic Stress LI Jiasi, LIU Yingqing, ZHANG Yongheng, ZHANG Ying'ao, XIAO Yezi, LIU Lu, YU Youben Journal of Tea Science    2023, 43 (3): 325-334.   DOI: 10.13305/j.cnki.jts.2023.03.007 Abstract （198）      PDF（pc） （1496KB）（113）       Knowledge map    Save Nine cis epoxide carotenoid dioxygenase (NCED) is a key rate-limiting enzyme in abscisic acid (ABA) synthesis and widely involved in plant growth and development as well as abiotic stress response. CsNCED2 is involved in the response to drought and salt stress in tea plants, while the transcriptional regulation mechanism involved is still unclear. In this study, two transcription factors, CsDof5.4 and CsERF38, which binded to the CsNCED2 promoter were identified by yeast single hybrid (Y1H) library screening. Subcellular localization, yeast self-activation and luciferase (LUC) assay show that they were located in the cell nucleus and could activate the expression of CsNCED2. RT-qPCR results show that the expressions of CsERF38 and CsDof5.4 were highly correlated with CsNCED2 under salt stress. While under drought stress, only the expression of CsERF38was highly correlated with that of CsNCED2. In this study, two transcription factors (CsDof5.4 and CsERF38) binding to the CsNCED2 promoter were identified. Both drought and salt stresses could induce the expression of CsNCED2, thus participate in the abiotic stress response in tea plants. Reference | Related Articles | Metrics

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Preparation of a Cross-linked Polyphenol Oxidase Aggregate Based on Catechins and Its Efficient Catalytic Synthesis of Theaflavin-3,3ʹ-digalate ZHOU Jinghui, LIU Changwei, ZHANG Sheng, XU Gang, XU Wei, HUANG Jian′an, LIU Zhonghua Journal of Tea Science    2023, 43 (3): 377-388.   DOI: 10.13305/j.cnki.jts.2023.03.005 Abstract （194）      PDF（pc） （1818KB）（133）       Knowledge map    Save In order to prepare theaflavin more efficiently and economically, catechins were used as the cross-linking reagent in this study, and a polyphenol oxidase (tyrosinase) crossed-linked aggregate derived from Bacillus megaterium was prepared and used for the synthesis of theaflavin-3,3ʹ-digalate. Through optimization of enzyme cross-linking parameters and the catalytic performance before and after cross-linking, the results show that the optimal enzyme activity recovery rate of cross-linked enzyme (200 U·mL-1) could be obtained at pH 4.0, EGCG 0.5 mg·mL-1 and cross-linking time 50 min. Compared with free enzymes, cross-linked enzymes showed better catalytic performance (thermal stability, organic solvent tolerance, substrate tolerance). When the cross-linked enzyme was used to synthesize theaflavin-3,3′-digallate, the concentration of the product could reach 800 μg·mL-1, and the cross-linked enzyme could be reused for at least three batches. This method could significantly reduce the application cost of theaflavin, which has potential industrial application value. Reference | Related Articles | Metrics

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Diversity Analysis of Leaf Phenotype and Biochemical Components in Tea Local Population Resources TANG Lu, LI Changle, GE Yue, WANG Pu, ZHAO Hua, WANG Mingle, WANG Yu, GUO Fei, NI Dejiang Journal of Tea Science    2023, 43 (4): 473-488.   DOI: 10.13305/j.cnki.jts.2023.04.008 Abstract （194）      PDF（pc） （528KB）（205）       Knowledge map    Save In order to protect tea germplasm resources and promote tea germplasm innovation, the phenotypic character and biochemical component diversity of 32 tea germplasm resources from 12 provinces were studied. The results showed that the genetic diversity index of 16 phenotypic character ranged from 0.81 to 1.94, and the phenotypic genetic diversity of the test population was high. The cumulative contribution rate of the six phenotypic characters including leaf area, leaf shape, leaf upper surface, young shoot pubescence, leaf tip shape and leaf cross section were 71.78%, which was the main factor causing the phenotypic difference of the tested tea population. Based on the determination results of biochemical components in two years, the variation coefficient of caffeine content (17.95% and 14.55%) was the largest, followed by the variation coefficient of tea polyphenol content (13.61% and 8.11%). The variation coefficient of free amino acid (5.62% and 7.52%) was the lowest. Cluster analysis based on the results of biochemical component content determination was conducted to divide the tested tea tree populations into three groups, each including different types of germplasm. From the geographical distribution of the tested tea populations, the content of biochemical components showed regional differences. Reference | Related Articles | Metrics

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Glyphosate-stress Effects on Shikimic Acid in Tea Leaves LIU Hongxia, LIU Yingying, CHEN Hongping, CHAI Yunfeng Journal of Tea Science    2023, 43 (5): 657-666.   DOI: 10.13305/j.cnki.jts.2023.05.005 Abstract （194）      PDF（pc） （1058KB）（110）       Knowledge map    Save To investigate the effect of glyphosate stress on the growth and shikimic acid metabolism of tea (Camellia sinensis L.) plants, tea seedlings were cultured in nutrient solution with different concentrations of glyphosate and the visual phytotoxicity on tea leaves was observed. The non-targeted analysis of non-volatile metabolites in the leaves and quantitative determination of shikimic acid and glyphosate in the leaves were carried out by ultra-high performance liquid chromatography-quadrupole orbitrap high-resolution mass spectrometry. The results show that the tea seedlings under the high dose of glyphosate (200 mg·L-1) treatment exhibited characteristics of pesticide damage, while the tea seedlings under the low dose of glyphosate (50 mg·L-1) treatment and control did not show apparent pesticide damage. Mass spectrometric and statistical analysis indicates that there were significant changes in the contents of shikimic acid pathway metabolites in the leaves of glyphosate-treated tea seedlings, with shikimic acid being one of the main differential metabolites. Within 21 d, the accumulation of shikimic acid in leaves was highly positively correlated with the absorption amount and action time of glyphosate. When the absorption amount of glyphosate was larger than 28 mg·kg-1, the shikimic acid metabolism in tea plants was significantly inhibited, resulting in a large accumulation of shikimic acid in tea leaves. Compared with the control group, the content of shikimic acid in tea leaves affected by pesticides increased about 16-fold. This study shows that shikimic acid is one of the main metabolites of tea plants in response to glyphosate stress. Reference | Related Articles | Metrics

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Catalytic Function, Promoter Structure and Functional Analysis of CsNUDX1-cyto in Different Tea Cultivars YANG Jihong, ZHOU Hanchen, XU Yujie Journal of Tea Science    2023, 43 (5): 621-630.   DOI: 10.13305/j.cnki.jts.2023.05.001 Abstract （193）      PDF（pc） （1842KB）（139）       Knowledge map    Save Geraniol is an important monoterpenoid in tea plants, and its accumulation varies greatly among different tea cultivars. The recent study shows that CsNUDX1-cyto is responsible for the production of geraniol and its glycosides in tea plants. In order to explore the differences in the catalytic function and regulation of CsNUDX1-cyto in different tea cultivars, this study analyzed the differences in the accumulation of geraniol and expression patterns of CsNUDX1-cyto, and analyzed the differences in the catalytic function, promoter structure and function of CsNUDX1-cyto in seven tea cultivars. The result shows that CsNUDX1-cyto expression was positively correlated with geraniol content (r=0.805). The content of geranyl in fresh leaves of Camellia sinensis var. sinensis (CSS) was significantly higher than that in C. sinensis var. assamica (CSA) cultivars. Agrobacterium tumefaciens-mediated genetic transformation system shows that CsNUDX1-cyto of different tea cultivars could promote the biosynthesis of geraniol. Analysis of promoter activity shows that CsNUDX1-cyto promoter had the weakest activity in ‘Yunkang 10’, and the structural analysis shows that the promoter of CsNUDX1-cyto in ‘Yunkang 10’ had an 185 base sequence insertion at the transcription start site -33, making the enhancing element CAAT-box located at -133 (CAAT-boxes in other cultivars were located at -47). The results of this study indicate that CsNUDX1-cyto in different tea cultivars could promote geraniol biosynthesis, but the genetic diversity of the promoter region results in differences in its expression level. Reference | Related Articles | Metrics

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Data Enhancement Optimization and Class Activation Mapping Quantitative Evaluation for CNN Image Recognition of Multiple Tea Categories ZHANG Zhanyi, ZHANG Baoquan, WANG Zhouli, YANG Yao, FAN Dongmei, HE Weizhong, MA Junhui, LIN Jie Journal of Tea Science    2023, 43 (3): 411-423.   DOI: 10.13305/j.cnki.jts.2023.03.006 Abstract （191）      PDF（pc） （1936KB）（405）       Knowledge map    Save There are many kinds of tea in China, and subjective identification is easy to be confused and very dependent on professional experience. Convolutional Neural Network (CNN) image recognition applied to multi-tea identification has the advantages of objectivity, adaptability to complex image backgrounds and portability to mobile devices. However, the current CNN image recognition of tea lacks data enhancement optimization and objective evaluation of recognition accuracy, which limits the robustness and generalization ability of model recognition. In this study, a total of 6 123 images of 29 common tea categories were collected to construct a dataset, and the ResNet-18 (Residual network-18) training effects of 10 image data enhancement methods were compared. To objectively evaluate the accuracy of the model recognition area, two gradient-weighted class activation mapping (Grad-CAM ) quantitative evaluation indexes (IOB and MPI) were constructed. The results show that grid erasure (Ratio=0.3), resolution perturbation and HSV (Hue, Saturation, Value) color space perturbation are better data enhancement methods, with four indicators of accuracy, loss, IOB and MPI performing better. Furthermore, through the ablation experiment, the optimal combination of data enhancement methods “horizontal mirror flip + grid erasure (Ratio=0.3) + HSV color perturbation” was obtained. The accuracy rate of model test reached 99.82%, with a loss value of only 0.64, and the IOB and MPI indicators also performed better, reflecting good accuracy in image recognition. This study optimized the tea image data enhancement method, and obtained the multi-tea CNN image recognition model with high robustness. The constructed quantization indexes IOB and MPI also solved the problem of accuracy evaluation of CAM recognition region. Reference | Related Articles | Metrics

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Comparison of Soluble and Membrane-bound Polyphenol Oxidase from Cultivars Suitable to Ninghong Tea Production ZHAN Kun, YANG Zhengli, XU Ziyi, LAI Zhangfeng, LI Jun, CHEN Luojun, ZHOU Sixi, LI Mingxi, GAN Yudi Journal of Tea Science    2023, 43 (3): 356-366.   DOI: 10.13305/j.cnki.jts.2023.03.003 Abstract （189）      PDF（pc） （459KB）（78）       Knowledge map    Save In order to investigate the enzymatic properties of polyphenol oxidase (PPO) in cultivars suitable for Ninghong tea production, as well as to increase the theaflavin content in Ninghong tea, one bud and two fresh leaves from ‘Ningzhou population’, ‘Ningzhou 2’ and ‘Dayelong’ were used as raw materials to obtain membrane-bound polyphenol oxidase (mPPO) and soluble polyphenol oxidase (sPPO) crude enzymes and to analyze the enzymatic properties. Using catechol as the substrate, the mPPO specific activity of each cultivar was higher than sPPO specific activity. mPPO specific activity of ‘Dayelong’ was the highest (542.59±25.13 U·mg-1), and sPPO activity of ‘Ningzhou 2’ was the lowest (112.57±14.01 U·mg-1). The optimum reaction temperature for mPPO was 40-60 ℃, the optimum reaction temperature for sPPO was 30-50 ℃, and the highest optimum reaction temperature for mPPO of ‘Ningzhou 2’ and ‘Dayelong’ was 55 ℃. The lowest sPPO optimum reaction temperature for ‘Ningzhou 2’ and ‘Ningzhou population’ was 35 ℃. The optimum pH of sPPO ranged from 7.00-8.50 with one peak, while the optimum pH of mPPO ranged from 5.00-8.00 with two peaks. The optimum pH of sPPO in ‘Ningzhou population’ was 8.00, and the optimum pH of mPPO in ‘Ningzhou 2’ was 5.50. mPPO and sPPO had strong affinity for dihydroxy phenols, and mPPO in ‘Ningzhou 2’ had the strongest affinity for catechol and the highest catalytic efficiency. Ascorbic acid had the best inhibitory effect on sPPO in ‘Ningzhou population’. While halide inhibitors had no inhibitory effect on both sPPO and mPPO activities in tea cultivars suitable for Ninghong tea production. EDTA had an activating effect on mPPO. The thermal deactivation of sPPO and mPPO in these tea cultivars followed the primary reaction kinetics, with mPPO in ‘Dayelong’ having the best thermal resistance, the worst thermal sensitivity, and the weakest sensitivity to temperature. While sPPO in ‘Ningzhou population’ had the worst thermal resistance. The sPPO of ‘Ningzhou population’ was the worst heat-resistance, the highest heat-sensitivity and temperature-sensitivity. The results show that there were some differences in the sPPO and mPPO enzyme properties among the cultivars. Tea cultivar ‘Dayelong’ had the highest mPPO specific activity and the best heat resistance, which provided a suitable enzyme source for the processing of high theaflavin Ninghong tea. This study also provided a theoretical reference for the actual Ninghong tea production. Reference | Related Articles | Metrics

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Genetic Analysis and Marker Development for Wuyi Tea (Camellia sinensis, Synonym: Thea bohea L.) Based on GBS-SNP LI Li, LUO Shengcai, WANG Feiquan, LI Xiangru, FENG Hua, SHI Yutao, YE Jianghua, LIU Fei, ZHAO Jialin, LI Shuying, ZHANG Bo Journal of Tea Science    2023, 43 (3): 310-324.   DOI: 10.13305/j.cnki.jts.2023.03.001 Abstract （181）      PDF（pc） （4730KB）（94）       Knowledge map    Save In order to understand the genetic diversity background of Wuyi tea (Camellia sinensis, Synonym: Thea bohea L.), 126 Wuyi tea cultivars/strains and 223 elite tea cultivars/strains (a total of 349 tea germplasm resources) from 12 different regions were collected. Genotyping by sequencing (GBS) technology was used to screen 973 high-quality core SNPs for genetic diversity and background analysis. Model-based structure (Structure), phylogenetic tree construction (NJ-tree) and principal component analysis (PCA) show that the 349 tea resources could be divided into 5 subgroups, and the clustering of subgroups was mainly based on the genetic relationship between tea resources, rather than morphological characteristics such as tree type or leaf shape. Gene flow analysis shows that Wuyi tea might have spread from southern Fujian Province to Wuyi Mountain in northern Fujian Province and from Wuyi Mountain to Zhejiang Province. Genetic similarity analysis shows that among 349 tea cultivars/strains, 136 pairs of cultivars/strains had genetic similarity greater than 0.9, among which 26 pairs involved Wuyi tea. Based on the results of gene flow and genetic similarity, the genetic relationship and background of some representative and controversial Wuyi tea were discussed and analyzed. Furthermore, through the discernibility analysis of pairwise comparison, 21 SNPs were selected from 973 SNP markers that can 100% identify 349 tea cultivars/strains, among which 18 SNPs could 100% identify 126 Wuyi tea cultivars/strains. Genetic fingerprints were established and identification primers were developed. These results provided valuable information for the management and breeding of Wuyi tea in the future. Reference | Related Articles | Metrics

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Regulatory Effect and Mechanism of EGCG on Metabolic Disorders in High-fructose Diet Mice ZHOU Jihong, CHEN Wei, DING Lejia, WANG Yuefei Journal of Tea Science    2023, 43 (3): 399-410.   DOI: 10.13305/j.cnki.jts.2023.03.012 Abstract （181）      PDF（pc） （3419KB）（201）       Knowledge map    Save This study investigated the effects and mechanisms of epigallocatechin gallate (EGCG) on high-fructose diet-induced metabolic disorders. Fifteen male SPF C57BL/6 mice were randomly divided into three groups: normal diet group (NCD), high-fructose diet group (HFD), and high-fructose diet supplemented with 1% EGCG group (HFE), with 5 mice in each group. After 8 weeks of feeding, the body weight, energy utilization rate, ALT and AST levels, as well as tissue morphology staining of the mice were measured. Furthermore, hepatic TNF-α, IL-1β, IL-6 and intestinal IL-6 inflammatory cytokine levels were detected by ELISA. The expressions of Srebp-1c, Tlr4, Myd88 in liver and Zo-1, Occludin, Tlr4 and Myd88 in intestine were measured by quantitative real-time PCR. Protein expressions of ZO-1 and Occludin were detected by IHC. The results show that dietary supplementation of EGCG could effectively reduce high-fructose diet-induced body weight gain, fat accumulation, hepatic and intestinal inflammatory responses, and could improve the intestinal barrier function by upregulating the expression of Zo-1 and the protein expressions of ZO-1 and Occludin. It also modulated lipid metabolism by reducing the expression level of Srebp-1c in liver, and downregulated the expression levels of inflammatory-related genes (Tlr4 and Myd88) in colon and liver. The results above suggest that dietary supplementation of EGCG has a preventive effect on high-fructose diet-induced metabolic disorders and inflammatory responses, and its mechanism may be related to the regulation of the gut-liver axis mediated by the TLR4/MyD88 signaling pathway. Reference | Related Articles | Metrics

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Study on the Differences of Leaf Color and Volatiles of Different Insect-resistance Tea Cultivars SUN Yue, LIU Mengyue, GAO Chenxi, WU Quanjin, CAO Shixian, YU Shuntian, CHEN Zhidan, JIN Shan, SUN Weijiang Journal of Tea Science    2023, 43 (4): 525-543.   DOI: 10.13305/j.cnki.jts.2023.04.005 Abstract （178）      PDF（pc） （2465KB）（103）       Knowledge map    Save In order to explore the differences in leaf color and volatiles of different insect-resistant tea cultivars, a two-year field population density survey was conducted on 11 tea cultivars. Through the indoor incubation test of field branches and the indoor life parameter determination test, the reliability of field population density as the resistance grading standard was proved. The color difference and wax content per unit leaf area of leaves were determined, and the volatiles of new shoots of one bud and two leaves that were not harmed by pests and diseases were detected by gas chromatography-mass spectrometry (GC-MS) in order to screen the differences among different insect-resistant tea cultivars. The results show that, M. onukii preferred tea cultivars with darker, lighter yellow leaves. D minowai preferred tea cultivars with brighter, more saturated colors and a higher yellow color, and D minowai placed more emphasis on the color of the leaf back. In terms of volatiles, the population densities of M. onukii were significantly and positively correlated with the relative content of linalool and negatively correlated with the relative contents of nonanal and dodecane. Population densities of D. minowai were significantly and positively correlated with the relative levels of dodecane and phenylethanol. The effects of dodecane on M. onukii and D. minowai were opposite, and the same trend was observed for the relationship between wax and population density in tea leaves, suggesting that the same volatile substance may have different reactions to different insects. Reference | Related Articles | Metrics

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Research on the Effect Evaluation and Dynamic Mechanism of the Integrated Development of Tea and Tourism Industry LIN Xi, WU Qinyao, YANG Jiangfan Journal of Tea Science    2023, 43 (5): 718-732.   DOI: 10.13305/j.cnki.jts.2023.05.011 Abstract （176）      PDF（pc） （624KB）（116）       Knowledge map    Save This study was based on the theories of industry integration, industry chain value, and coupling coordination, as well as previous research results. Taking the development level of the tea industry and tourism industry in the eight main tea-producing areas in China from 2011 to 2020 as the empirical research object, a quality evaluation index system for the development of the tea and tourism industry was constructed, and the coupling coordination model and spatial analysis method were used to evaluate and present the effect of tea tourism integration. And regression models were used to explore the driving mechanism of tea tourism integration development. The results indicate that the tea and tourism industries in the main tea-producing areas over the past decade were highly coupled, which were present in the middle to late stages of integrated development. The overall trend shows a spatial feature of "high in the middle and low on both sides", with an inverted "U" shape in the east-west direction. The high value area at the provincial level has always been Yunnan Province. The driving force mechanism is the joint influence of internal and external factors: the internal driving force is the internal coupling between the tea and tourism industries, which drives the formation of a new business model: the integration of tea and tourism. In terms of external macro environment, policy guidance and support are the leading forces, sustained economic development is the driving force, social and cultural prosperity is the pulling force, and technological innovation and application are the supporting forces. Suggestions were also made on further promoting the integrated development of tea tourism consisting of strengthening government guidance and support to improve factor protection, promoting the improvement of industry quality and efficiency to consolidate the foundation of development, digging and highlighting cultural connotations to expand the depth of development, applying technology to cultivate talents and thus strengthen development support. Reference | Related Articles | Metrics