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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 （542）      PDF（pc） （477KB）（392）       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 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 （498）      PDF（pc） （733KB）（518）       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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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 （402）      PDF（pc） （475KB）（553）       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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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 （387）      PDF（pc） （1492KB）（476）       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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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 （312）      PDF（pc） （1988KB）（389）       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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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 （306）      PDF（pc） （528KB）（329）       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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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 （305）      PDF（pc） （2029KB）（277）       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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Construction of Polyphenol Self-assembly Antibacterial Biomaterials and Progress in Their Applications XU Wei, YU Rongxin, ZHANG Xiangchun, ZHANG Yiwen, CHEN Hongping, TIAN Baoming, ZHENG Qinqin, WU Yuanyuan, XIA Chen, WEI Bing Journal of Tea Science    2024, 44 (1): 1-15.   DOI: 10.13305/j.cnki.jts.2024.01.004 Abstract （303）      PDF（pc） （4782KB）（254）       Knowledge map    Save Bacterial infection, a leading cause of global mortality, can result in various diseases. While antibiotics are the primary treatment for infections, their excessive and irrational use has led to the emergence of a variety of bacterial drug resistance, posing a serious threat to human health. Plant polyphenols have natural antibacterial properties, but the instability of the phenolic hydroxyl structure limits their bioavailability. To solve this problem, researchers have explored the self-assembly of polyphenols with other substances to construct new nano-biomaterials. These biomaterials not only enhance the stability and bioavailability of polyphenols but also exhibit synergistic antibacterial activity, showing a great promise in the field of antibacterial applications. This review examined the construction strategies and antibacterial properties of different types of polyphenol self-assembled biomaterials developed in recent years, including polyphenol-metal, polyphenol-hydrogel, polyphenol-chitosan, polyphenol-protein and polyphenol-liposome. Furthermore, the challenges and future prospects of the novel polyphenol self-assembling biomaterials in the field of antibacterial application were discussed. 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 （296）      PDF（pc） （1970KB）（317）       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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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 （275）      PDF（pc） （1058KB）（170）       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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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 （269）      PDF（pc） （624KB）（206）       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

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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 （263）      PDF（pc） （1842KB）（218）       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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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 （249）      PDF（pc） （2465KB）（114）       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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Study on the Control Effect of Chemical Pesticides on the Empoasca onukii Adults ZOU Jiating, GUO Yuhang, BIAN Lei, LUO Zongxiu, LI Zhaoqun, XIU Chunli, FU Nanxia, CAI Xiaoming Journal of Tea Science    2023, 43 (4): 544-552.   DOI: 10.13305/j.cnki.jts.2023.04.003 Abstract （248）      PDF（pc） （419KB）（101）       Knowledge map    Save Empoasca onukii is an important pest in tea gardens. Currently, the control was mainly depended on chemical pesticides, but less attention was paid to the control effect on the adults. In this study, the control effects of chemical pesticides on the adult E. onukii were evaluated through field experiments, and the reasons for the poor control efficiency were investigated by laboratory test. The results show that the chemical pesticides with good control effects on nymphs in the field did not have ideal control effects on adults. Indoor studies have shown that when spraying the entire tea shoots at concentrations even lower than those in the field, the adult mortality rates were 100%. Furthermore, the adult mortality rates were the highest (63.33%~71.67%) when the pesticides were applied at the middle part of tea plant shoots, and the adult mortality rates were the lowest (20.00%~28.33%) when applied at the top of shoots. Moreover, the adult mortality rate could be increased by increasing the shading range around the shoots or reducing the light intensity at the top of the shoots, when the pesticides were applied at the top of shoots. These results indicate that the main reason for the poor control efficiencies of chemical pesticides on the adult E. onukii in field is that the adults mainly live in the middle part of tea plant shoots. This phenomenon should also be related with light intensity. This finding provided a reference for the control of the adult E. onukii, and helped to enhance the control effects of chemical pesticides on E. onukii. Reference | Related Articles | Metrics

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Exploratory Study on the Image Processing Technology-based Tea Shoot Identification and Leaf Area Calculation LÜ Danyu, JIN Zijing, LU Lu, HE Weizhong, SHU Zaifa, SHAO Jingna, YE Jianhui, LIANG Yuerong Journal of Tea Science    2023, 43 (5): 691-702.   DOI: 10.13305/j.cnki.jts.2023.05.007 Abstract （239）      PDF（pc） （2181KB）（156）       Knowledge map    Save In this study, based on the picture collection of tea shoot growth in the field, we used deep learning target detection algorithm YOLOv5 to construct a model for identifying different growth stages of tea shoots, and the testing results indicate that the model had high accuracy. Furthermore, the Image-J software and the image processing methods of threshold cutting based on Gray, RGB and HSV values were applied to process tea leaf area, and the accuracy and efficiency of different methods were compared. The results show that the accuracy of HSV-based algorithm system of cutting tea leaves and automatically calculating tea leaf area was over 94%, which had better performance than RGB-based algorithm system. The research results provide technical support for the intelligent recognition model of tea growth state and information extraction algorithm of leaf traits, and also build a theoretical basis for the development of tea bud automatic recognition module of tea plucking machinery. Reference | Related Articles | Metrics

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Exploring the Potential Mechanism of Hypoglycemic Effect of Fungus Fermented Black Tea Based on Liver Transcriptomics ZENG Hongzhe, PENG Liyuan, WAN Liwei, LIU Changwei, FANG Wenwen, WANG Kuofei, ZHANG Xinyi, WEN Shuai, HUANG Jian'an, LIU Zhonghua Journal of Tea Science    2023, 43 (5): 645-656.   DOI: 10.13305/j.cnki.jts.2023.05.003 Abstract （238）      PDF（pc） （2294KB）（251）       Knowledge map    Save EGCG is often regarded as the main active ingredient in tea to protect blood glucose homeostasis. The content of low molecular weight polyphenols such as EGCG in fungus fermented black tea (FFBT) is extremely low, and there are few studies on the hyperglycemic effect of FFBT. To explore the hypoglycemic effects and potential mechanisms of FFBT, GK rats with spontaneous hyperglycemic were given 280 mg·kg-1 FFBT extract (equivalent to 9 g of FFBT for daily human consumption) by gavage intervention. The study assessed the effects of FFBT on body weight, glucose homeostasis, regulatory factors related to glucose homeostasis, diabetic complications and liver transcription profiles in hyperglycemic rats. The results indicated that FFBT could obviously reduce the fasting blood glucose level and random blood sugar level of hyperglycemic rats, improve the abnormal glucose metabolism in hyperglycemic rats, maintain glucose homeostasis and alleviate the damage caused by diabetic complications in hyperglycemic rats. In addition, transcriptome analysis revealed that the hypoglycemic properties of FFBT might be related to the regulation of gene expression in the liver, such as Gck, Pklr, Pkm. This study found that FFBT may be a potential hypoglycemic functional beverage, providing a theoretical basis for the development and utilization of fermented tea such as FFBT. Reference | Related Articles | Metrics

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Study on the Influence of Tea Green Leafhopper Infestation on the Tenderness of Fresh Tea Leaves and the Extraction Rate of Metabolites Related to Oolong Tea Quality WU Shuhua, MAO Kaiquan, CHEN Jiaming, LI Jianlong, XUE Jinghua, ZENG Lanting, YANG Yuhua, GU Dachuan Journal of Tea Science    2023, 43 (6): 806-822.   DOI: 10.13305/j.cnki.jts.2023.06.005 Abstract （237）      PDF（pc） （4187KB）（201）       Knowledge map    Save Tea green leafhopper is a major insect widely distributed in tea gardens, which has a significant impact on the yield and quality of tea. However, the effects of tea green leafhopper infestation on the tenderness of fresh tea leaves and the extraction rate of metabolites related to oolong tea quality remain unclear. By means of shear force measurement, broken tea rate analysis, oolong tea brewing, metabolite analysis and correlation analysis, it was found that the infestation of tea green leafhoppers significantly increased the contents of cell wall materials lignin, cellulose and pectin, and decreased the tenderness of fresh tea leaves and broken tea rate. The extraction rates of tea polyphenols, free amino acids, soluble sugars, catechin monomers, amino acid monomers and theanine were affected. Moreover, except for epicatechin gallate (ECG), the extraction of these taste substances and the tenderness of fresh tea leaves were significantly correlated with the contents of cell wall materials. In this study, the extraction rule of taste quality metabolites after tea green leafhoppers infestation was explored, and the influence of tea green leafhopper infestation on quality traits was explored from three aspects: tea picking, processing and brewing. Reference | Related Articles | Metrics

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Changes in Chemical Composition of Zijuan Tea under Anaerobic Treatment Conditions and Their Effects on in vitro ACE Activity YANG Gaozhong, SHI Jiang, ZHANG Yue, PENG Qunhua, LIN Zhi, LÜ Haipeng Journal of Tea Science    2023, 43 (4): 553-566.   DOI: 10.13305/j.cnki.jts.2023.04.007 Abstract （231）      PDF（pc） （1565KB）（356）       Knowledge map    Save In this study, fresh leaves of Zijuan tea were treated with anaerobic treatment and used to make freeze-dried, green, black and white tea samples. The main non-volatile components (such as catechins, amino acids, anthocyanins) in these samples were determined and their in vitro angiotensin-converting enzyme (ACE) inhibitory activities were evaluated by high performance liquid chromatography. In addition, molecular docking simulation experiments were conducted to investigate the potential interaction mechanisms between the major chemical components in tea and ACE. The results show that the GABA content in the freeze-dried samples after anaerobic treatment increased to 1.72 mg·g-1, which was significantly higher than that in the tea samples without anaerobic treatment (0.04 mg·g-1, P<0.05). The composition and contents of amino acids and polyphenolic compounds in the tea samples were significantly affected by the processing methods after anaerobic treatment. The white tea process could increase the contents of amino acid components in the tea samples, while the freeze-drying process could maximize the retention of polyphenolic compounds in the tea samples. The in vitro ACE inhibitory activity of Zijuan tea fresh leaf samples was significantly enhanced after anaerobic treatment (P<0.05); the strongest ACE activity inhibition was observed in samples prepared by freeze-drying process after anaerobic treatment, which was significantly higher than that of samples prepared by green, white, and black tea processing methods (P<0.05). In addition, molecular docking simulation experiments reveal that the strength of the interaction between the main chemical components in tea and ACE was related to the hydrophilic groups and aromatic ring structures in their molecular structures. The results of the study helped to reveal the effect of anaerobic treatment on the ACE inhibitory activity of Zijuan tea and provided a theoretical basis for the development of special functional Zijuan tea products with potential treatment of hypertension. Reference | Related Articles | Metrics

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Geochemical Characteristics and Risk Assessment of Heavy Metals in Typical Tea Gardens in Yunnan Province XIE Mengli, CHANG He, ZHOU Xiaohua, YANG Tianfu, LONG Kun Journal of Tea Science    2023, 43 (4): 501-512.   DOI: 10.13305/j.cnki.jts.2023.04.004 Abstract （224）      PDF（pc） （963KB）（316）       Knowledge map    Save In order to explore the relationship and the current situation between the geological background of tea garden and the content of heavy metal elements in tea, the rocks, soil and tea in Mengku tea garden and Jingmai tea garden in Yunnan Province were selected as the research objects. The contents of 10 heavy metal elements (Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn, Mn, As) were determined. Multivariate statistical analysis and spatial analysis were used to summarize the characteristics and risk assessment of heavy metals in tea gardens. The results show that: (1) compared with the abundance of elements in the crust, the rocks in Mengku and Jingmai tea gardens were rich in As. While the rocks of Mengku tea garden were poor in Hg and the rocks of Jingmai tea garden were poor in Mn. (2) The soil of Mengku tea garden was mainly polluted by As and Cr. The soil of Jingmai tea garden was mainly polluted by Cr and Cu. They were all lightly polluted and had good soil quality. (3) The average contents of heavy metal elements in tea followed the order of Mn>Zn>Cu>Ni>Cr. The accumulation ability followed the order of Mn>Zn>Hg>Cu>Ni. Only a few tea samples from Mengku tea garden had As content exceeding the standard. And the heavy metal contents in tea were generally at the safe level. (4) For tea samples from Mengku and Jingmai tea gardens, Mn had the highest non-carcinogenic risk. As in Mengku tea had the highest carcinogenic risk. Cr in Jingmai tea had the highest carcinogenic risk. And other heavy metal elements were within the safe range. Reference | Related Articles | Metrics

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Study on Characteristic Flavor Substances in Tea Aroma Type Distilled Spirit Based on GC-MS and GC-O HUANG Cui, WANG Fengli, CHEN Yaolin, YU Jiajun, WANG Wei, DU Sufeng, SONG Tao, CAI Zhongshui, XUE Jie, WU Yun Journal of Tea Science    2023, 43 (5): 703-717.   DOI: 10.13305/j.cnki.jts.2023.05.002 Abstract （219）      PDF（pc） （880KB）（190）       Knowledge map    Save As a further extension of the deep processing technology of tea raw materials, tea aroma type distilled spirit combines the aroma of tea and wine, and has a unique flavor. In order to clarify the changes of flavor substances of tea aroma type distilled spirit under different processes, solid-phase microextraction/gas chromatography-mass spectrometry was used to analyze the flavor components. The odor specific magnitude estimation method and Odor activity value method in liquid-liquid extraction/gas chromatography-olfactometry-mass spectrometry were used to determine the characteristic flavor substances and their contribution to the overall flavor. The results show that 76 kinds of aroma substances were detected, including 32 esters, 14 alcohols, 10 aldehydes and ketones, 4 acids, 13 terpenes and 3 other substances. Gas chromatography-olfactometry mass spectrometry analysis results show that there were 21 aroma compounds that could be smelled, and 12 key aroma compounds were identified by OAV and OSME together, including linalool (rose flowers), anisole (herbal), ethyl caprate (fruit), ethyl caproate (wine aroma) and so on. The results show that different kinds of microorganisms, fermentation methods and distillation technology significantly affected the composition and contents of flavor substances in tea aroma type distilled spirit. The results of this study have important guiding significance for the characteristic aroma characterization and quality control of tea aroma type distilled spirit. Reference | Related Articles | Metrics