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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 （617）      PDF（pc） （4782KB）（698）       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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A Grading Identification Method for Tea Buds Based on Improved YOLOv7-tiny HONG Konglin, WU Minghui, GAO Bo, FENG Yening Journal of Tea Science    2024, 44 (1): 62-74.   DOI: 10.13305/j.cnki.jts.2024.01.006 Abstract （382）      PDF（pc） （2946KB）（436）       Knowledge map    Save The intelligent grading and recognition of tea buds in a natural environment are fundamental for the automation of premium tea harvesting. To address the problems of low recognition accuracy and limited robustness caused by complex environmental factors like lighting, obstruction, and dense foliage, we propose an enhanced model based on YOLOv7-tiny. Firstly, a CBAM module was added into the small object detection layer of the YOLOv7-tiny model to enhance the model's ability to focus on small object features and reduce the interference of complex environments on tea bud recognition. We adjusted the spatial pyramid pooling structure to lower computational costs and improve detection speed. Additionally, we utilized a loss function combining IoU and NWD to further enhance the model's robustness in small object detection by addressing the sensitivity of the IoU mechanism to position deviations. Experimental results demonstrate that the proposed model achieves a detection accuracy of 91.15%, a recall rate of 88.54%, and a mean average precision of 92.66%. The model's size is 12.4 MB. Compared to the original model, this represents an improvement of 2.83%, 2.00%, and 1.47% in accuracy, recall rate, and mean average precision, respectively, with a significant increase of 0.1 MB in model size. Comparative experiments with different models show that our model exhibits fewer false negatives and false positives in multiple scenarios, along with higher confidence scores. The improved model can be applied to the bud grading and recognition process of premium tea harvesting robots. Reference | Related Articles | Metrics

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Study on the Spatiotemporal Evolution and Spatial Differentiation Pattern of Carbon Sink in China’s Tea Industry YUAN Liwen, ZHANG Junbiao, QIN Jiangnan Journal of Tea Science    2024, 44 (1): 149-160.   DOI: 10.13305/j.cnki.jts.2024.01.011 Abstract （371）      PDF（pc） （655KB）（363）       Knowledge map    Save The tea garden ecosystem has an important carbon storage function. Analyzing and evaluating the carbon sink level during the production and planting process of tea gardens is of great significance for scientifically evaluating the potential ecological value of tea gardens and promoting the green and low-carbon development of the tea industry. This paper selected data from 16 major tea producing provinces in China from 1978 to 2020, used biomass models of tea plant growth cycles and soil carbon content models to calculate and evaluate the basic situation of carbon sinks in China’s tea industry. The center of gravity fitting model was used to analyze the spatiotemporal evolution of carbon sinks in the tea industry, and the driving factors of spatial differentiation were explored in conjunction with geographic detector models. The results show that: (1) The total carbon sink of China’s tea industry had shown a phased growth trend, reaching 735.311 million tons in 2020, and the accumulation of soil carbon sink was higher than that of plant carbon sink. The carbon sink intensity showed a “rise-decrease-rise” characteristic. (2) There were significant differences in carbon sink intensity among different provinces in the tea industry. High-intensity provinces were concentrated in the eastern coastal and western regions of China, and the carbon sink gravity center had long been located within Hunan province, but there was a slight trend of westward displacement. (3) The agricultural subsidies and the development level of agricultural economy were important driving forces that affect the spatial distribution pattern of carbon sinks in China’s tea industry, but there were differences in the dominant factors for the spatial differentiation of carbon sinks in different regions. Based on this, this paper proposed relevant suggestions from the management and operation of carbon sinks in the tea industry, as well as the formulation of industrial policies. Reference | Related Articles | Metrics

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Risk Assessment and Source Analysis of Heavy Metal Pollution in Chinese Tea Gardens in 2000-2022 Based on Meta-analysis YANG Yanhu, CHEN Xiaohan, ZHANG Xiaoqing, REN Dajun, ZHANG Shuqin, CHEN Wangsheng Journal of Tea Science    2024, 44 (1): 37-52.   DOI: 10.13305/j.cnki.jts.2024.01.002 Abstract （363）      PDF（pc） （1446KB）（408）       Knowledge map    Save Heavy metal pollution is one of the important factors affecting the ecological environment of tea gardens and the safety of tea products. This study collected literature on heavy metal (Cu, Pb, As, Hg, Cd, Cr, Zn, Ni) pollutions in tea garden soils in major tea producing areas in China, including Hubei, Hunan, Fujian, Yunnan, Guizhou and Sichuan. The weight of a single study was obtained using meta-analysis method to obtain the weighted average of heavy metal concentrations in tea garden soils in each province and across the country. The potential ecological risk index method and geological accumulation index method were used for ecological risk assessment, and source analysis using the APCS-MLR model was applied. The results show that compared with the background values, all 8 heavy metals were enriched to a certain extent, with Hg and Cd pollutions being more severe. The moderate and above risks of Hg were mainly distributed in inland provinces such as Guizhou, Shaanxi, Sichuan and Anhui. The moderate and above risks of Cd were mainly distributed in coastal provinces such as Guangdong, Fujian, Zhejiang, Jiangsu, Shandong, Hainan, etc. The two heavy metals show mild to moderate risks. Compared with other countries in the world, tea gardens or agricultural land in developing countries generally have higher levels of heavy metals, with Cd and Hg being the elements with more severe pollution levels. The source analysis results show that the first, second, third, and fourth principal components are natural sources, industrial activity pollution sources, traffic exhaust pollution sources, and agricultural activity pollution sources, respectively. Industrial and agricultural activities are the main pollution factors, with Hg mainly coming from industrial activities and Cd mainly coming from agricultural activities. Reference | Related Articles | Metrics

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Research on the Path to Realize the Value of Tea Agricultural Cultural Heritage: Empirical Analysis Based on 31 Typical Cases MA Jie, YE Chaoyang, MAO Liyu Journal of Tea Science    2024, 44 (1): 161-174.   DOI: 10.13305/j.cnki.jts.2024.01.013 Abstract （362）      PDF（pc） （584KB）（397）       Knowledge map    Save The realization of the value of tea agricultural cultural heritage (TACH) is an important way for its protection and sustainable development. Based on the technology-organization-environment framework (TOE), this study explored the configuration effects of TOE condition variables on TACH value realization, as well as the linkage matching relationship among different elements. Based on 31 typical cases of TACH as research samples, the Fuzzy-sets qualitative comparative analysis (FsQCA) method was applied to explore the influencing factors and driving paths of TACH value realization. This study found that: (1) the realization of the value of TACH is the result of the combined action of necessary and sufficient conditions. (2) the realization of the value of high-level TACH is the result of the combination of core conditions and marginal conditions, with three typical models: "Collaborative Organizational Environment Type", "Social Resource Driven Type " and "Comprehensive Coupling Type". (3) The driving combination for the realization of non-high-level and high-level TACH value is asymmetric. Therefore, different paths could be chosen based on one's own resource endowment and external factors, in order to promote TACH value realization. Reference | Related Articles | Metrics

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Research Progress on the Mechanism of Natural Tea Components in Alleviating Acne WU Zhiyuan, WANG Kaibo, CHEN Silin, ZHAO Bi, SHEN Shiquan Journal of Tea Science    2024, 44 (1): 16-26.   DOI: 10.13305/j.cnki.jts.2024.01.010 Abstract （360）      PDF（pc） （1220KB）（414）       Knowledge map    Save Tea, as a natural beverage, is highly favored due to its clear health benefits. With in-depth research on the active ingredients of tea in recent years, it has been confirmed that natural components can have positive effects on various disease models. Acne is an inflammatory skin disease with a high prevalence and recurrence rate. In addition to traditional clinical diagnosis and treatment, complementary and alternative therapies represented by patches, skin care, and dietary improvement are also popular. In the market, more and more acne control products claim to add tea active ingredients to the raw materials. Natural components such as tea polyphenols, caffeine, theanine and tea saponins have shown great potential in alleviating acne. In this paper, the effects and molecular mechanisms of different functional components of tea on inhibiting sebum secretion, alleviating acne, improving skin microbial imbalance, and alleviating skin focal inflammation were reviewed, in order to provide reference for the research and development of tea natural products. Reference | Related Articles | Metrics

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Experimental Study on High-quality Tea Plucking by Robot LI Yatao, ZHOU Yujie, WANG Shaoqing, CHEN Jianneng, HE Leiying, JIA Jiangming, WU Chuanyu Journal of Tea Science    2024, 44 (1): 75-83.   DOI: 10.13305/j.cnki.jts.2024.01.003 Abstract （357）      PDF（pc） （1757KB）（436）       Knowledge map    Save This study evaluated the performance of a newly developed track-type tea plucking robot on Longjing tea picking, including its detection accuracy, localization accuracy, end effector plucking accuracy, time consumption across each stage. The results show that the detection success rate of the developed robot was 88.54%, the localization success rate was 84.07%, the end effector plucking success rate was 87.22%, and the overall plucking success rate was 61.30%. The plucked tea leaves met the requirements of middle-grade Longjing tea. The single tea shoot plucking time was approximately 1.51 s, and the machine could pluck over 2 000 tea shoots per hour, basically achieving the picking efficiency of one machine replacing one worker. Reference | Related Articles | Metrics

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Analysis of the Major Characteristic Aroma Compounds in Different Grades of Jingshan Tea ZHANG Huiyuan, MA Kuan, GAO Jing, JIN Yugu, WANG Yujie, SU Zhucheng, NING Jingming, CHEN Hongping, HOU Zhiwei Journal of Tea Science    2024, 44 (1): 101-118.   DOI: 10.13305/j.cnki.jts.2024.01.009 Abstract （337）      PDF（pc） （1818KB）（380）       Knowledge map    Save To characterize the difference of odorants among different grades of Jingshan tea, we investigated the super grade, the first grade, the second grade and the third grade of Jingshan tea by stir bar sorptive extraction gas chromatography-mass spectrometry (SBSE-GC-MS), headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and gas chromatography-olfactometry (GC-O) analysis. Herein, we detected and identified 161 volatile organic compounds. The differences between the four grades of Jingshan tea were revealed by principal component analysis (PCA) and hierarchical cluster analysis (HCA). The variable importance in projection (VIP) of the orthogonal partial least squares discriminant analysis (OPLS-DA) was used to determine candidate differential volatile compounds among tea samples of different grades and further screening of differential compounds was carried out through analysis of relative odor activity value (ROAV) and GC-O analysis. A total of 18 volatile compounds were identified as key odorants for the discrimination of different grades of Jingshan tea, including linalool, geraniol, indole, (Z)-jasmone, dimethyl sulfide, etc. Among them, the contents of hoterienol, methyl jasmonate, and indole in the super grade Jingshan tea were significantly higher than those in other grades, and together with (Z)-jasmone, δ-decalactone, and 1-octen-3-ol and other aroma-active compounds constitute the characteristic floral aroma of super grade Jingshan tea samples. This study revealed significant differences in the characteristic volatile compounds among different grades of Jingshan tea, providing a reference for distinguishing the grades of green teas by chemometrics combined with multivariate statistical analysis. Reference | Related Articles | Metrics

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Effects of Foliar Application of Different Concentrations of Organic-based Biostimulant Formulas on Yield and Quality of Tea (Camellia sinensis L.) in Red Soil Regions WANG Limin, CHEN Shiping, HUANG Dongfeng Journal of Tea Science    2024, 44 (1): 53-61.   DOI: 10.13305/j.cnki.jts.2024.01.007 Abstract （320）      PDF（pc） （903KB）（440）       Knowledge map    Save The purpose of this study was to evaluate the effect of different concentrations of organic-based biostimulant formulas (OBFs) on the yield and quality of tea (Camellia sinensis L.) in red soil regions. A field experiment was therefore conducted to investigate the nutrient uptake, yield, and quality of tea under different fertilization treatments. On the basis of conventional fertilization, foliar applications with the volume percentage concentration of OBFs including 0 (T0), 0.33% (T1), 0.66% (T2), 0.99% (T3), 1.32% (T4), and 1.65% (T5) were set up. The results show that foliar application of OBFs improved agronomic characteristics, enhanced nutrient uptake of tea plants and improved the tea yield and quality. Compared with the T0 treatment, tea yield in the T1, T2, T3, T4 and T5 treatments increased by 1.4, 1.4, 1.3, 2.1 and 2.4 times, respectively (P<0.05). In addition, as the concentrations of OBFs increased, the contents of total alkaloid, caffeine, and amino acids were first increased and then decreased. The contents of total alkaloid in the T1 and T2 treatments increased by 9.6% and 9.3%, caffeine increased by 9.3% and 11.4%, and amino acids increased by 5.0% and 12.4% in comparison with the T0 treatment, respectively (P<0.05). Meanwhile, under T1 and T2 treatments, nitrogen (N) uptake of tea leaves increased by 5.5% and 6.1%, phosphorus (P) increased by 19.9% and 13.3% and potassium (K) increased by 20.9% and 10.0%, respectively (P<0.05). Under T1 treatment, silicon (Si) increased by 14.8%. Furthermore, tea yield was positively correlated with bud density, 100-bud weight, leaf area and chlorophyll content. Meanwhile, the contents of total alkaloid and caffeine were positively related to N, P, K and Si contents in tea leaves, respectively. Similarly, there was a significant and positive relationship between N, P and K contents in tea leaves and the contents of amino acids and essential amino acids. Overall, foliar application with 1.65% OBFs could increase tea yield, while foliar application with 0.33% and 0.66% OBFs could promote N, P, K and Si uptake in tea leaves, improve agronomic characteristics, which is beneficial for tea yield and quality. Reference | Related Articles | Metrics

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Seasonal Dynamic Characteristics of Soil Physical and Chemical Properties and Enzyme Activities of Different Planting Patterns in the Wuyishan WANG Feng, CHANG Yunni, SUN Jun, WU Zhidan, CHEN Yuzhen, JIANG Fuying, YU Wenquan Journal of Tea Science    2024, 44 (2): 231-245.   DOI: 10.13305/j.cnki.jts.2024.02.004 Abstract （306）      PDF（pc） （1416KB）（412）       Knowledge map    Save Tea (Camellia sinensis L.) is one of the most important and traditional economic crops widely cultivated in the subtropical regions of China, which are usually developed from forestland. Soil enzyme activity is an important indicator of soil fertility and nutrient transformation. The purpose of this study is to investigate the seasonal dynamic characteristics of soil properties and enzyme activities of different planting patterns in Wuyishan city, and to provide theoretical basis for reasonable evaluation of soil ecological effects of organic tea cultivation. In this paper, three different planting patterns (forestland, conventional and organic tea gardens) were selected as the research objects. Soil samples were collected in May, August, November and February from 2021 to 2022. The soil properties and enzyme activities (urease, nitrate reductase, polyphenol oxidase, catalase, invertase and acid phosphatase) were determined in different seasons, and the dynamic changes with seasons were also investigated. The results show that: comparing with the forestland, the contents of soil ammonium nitrogen, total phosphorus, available phosphorus and available potassium increased significantly in the conventional tea garden, while the total potassium and pH decreased significantly. Compared with the conventional tea garden, the soil organic matter and total nitrogen contents increased significantly in the organic tea garden. The soil total phosphorus, available phosphorus, total potassium and available potassium contents decreased significantly. The soil pH also increased, and the proportion of soil nutrients was more coordinated. The effects of planting pattern and season and their interactions on urease and peroxidase activities were significant. Compared with the forestland, the soil urease, polyphenol oxidase, catalase and acid phosphatase activities decreased by 12.05% to 63.55% in the conventional tea garden, while urease activities significantly increased by 324.95% in the organic tea garden, and the soil nitrate reductase activities were not changed by planting mode. In general, the soil urease, polyphenol oxidase, invertase and acid phosphatase activities were significantly higher in summer and autumn (May and August) than those in winter and spring (November and February). The highest soil nitrate reductase and catalase activities were found in spring (February). The results of permutational multivariate analysis of variance show that the effect of planting pattern on the overall soil physical and chemical properties was much greater than that of seasonal changes. Redundancy analysis shows that soil environmental factors explained 77.03% of the variation in soil enzyme activity, and the soil organic matter, total nitrogen, ammonium nitrogen, total phosphorus, soil available phosphorus, total potassium, available potassium and pH were the main driving factors of soil enzymes. In summary, the conversion of forestland into tea gardens has a significant impact on soil properties and enzyme activities. Conventional planting leads to the accumulation of available phosphorus and potassium in tea garden soil and the decrease of soil enzyme activity, while organic planting improves soil enzyme activity and enhances soil carbon and nitrogen nutrient supply capacity, and thus is beneficial for maintaining a sustainable ecosystem in tea garden soil. Reference | Related Articles | Metrics

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Analysis of Flavor Characteristics and Biochemical Composition Differences of Ziyang Green Tea Based on Sensory Evaluation and Metabolomics Techniques CHEN Dequan, REN Yangmei, HE Mengdi, LI Youxue, YE Lili, XUE Huaqian, ZENG Jianming, DING Changqing Journal of Tea Science    2024, 44 (2): 316-328.   DOI: 10.13305/j.cnki.jts.2024.02.005 Abstract （299）      PDF（pc） （1171KB）（393）       Knowledge map    Save To analyze the differences in flavor characteristics and biochemical composition of Ziyang green tea with different drying processes, 6 Xixiangtea (hot-air convection drying combined with roller-type conduction drying) and 10 Cuifeng tea (hot-air convection drying) were used for the study, and their flavor profiles and biochemical composition were analyzed by sensory evaluation, component detection,UHPLC-Q-Exactive/TM and multivariate statistical methods. Sensory analysis shows that the aroma of Xixiang tea was mainly high-fresh, and the Cuifeng tea was mainly faint-scent. The color of Xixiang tea was darker green than that of Cuifeng tea. The overall sensory score of Cuifeng tea was higher than that of Xixiang tea. The quantitative analysis shows that the total amino acids and 10 amino acid fractions (histidine, arginine and threonine,…) were significantly higher in Xixiang tea than those in Cuifeng tea (P<0.05), but the contents of tea polyphenols, catechin fractions and caffeine, and other quality components, did not show significant differences. A total of 262 non-volatile compounds were identified by metabolomics analysis, including 13 classes of amino acids, catechins, dimeric catechins, phenolic acids, flavonoid glycosides and organic acids. Partial least squares discrimination and comparative analysis found that there was no difference in metabolite species between Xixiang tea and Cuifeng tea, but there was a difference in their contents. Compounds with VIP>1.2 were selected as key differential compounds, mainly amino acids, phenolic acids and flavonoid glycosides. The contents of amino acids and flavonoi dglycosides in Cuifeng tea were lower than those in Xixiang tea, while the content of dimerized catechins was higher than that of Xixiang tea. This study provided a theoretical basis for a comprehensive understanding of the formation of the quality of Xixiang tea and Cuifeng tea, as well as a reference for the sensory quality of dry tea and biochemical compositional differences due to different drying processes of green tea. Reference | Related Articles | Metrics

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The Mechanism and Research Progress of Epigallocatechin Gallate in Improving Non-alcoholic Fatty Liver Disease CHEN Jiaxin, ZHANG Jinjia, ZUO Huiling, JIAO Yuhang, SHI Anhua Journal of Tea Science    2024, 44 (4): 543-553.   DOI: 10.13305/j.cnki.jts.2024.04.003 Abstract （293）      PDF（pc） （655KB）（314）       Knowledge map    Save The incidence of nonalcoholic fatty liver disease (NAFLD) is increasing year by year and there is no specific drug available. The active ingredient of green tea, epigallocatechin gallate (EGCG), has been widely proven to have a favorable ameliorative effect on NAFLD in the low dose range. Some of the mechanisms by which EGCG delays the development of NAFLD through anti-oxidative stress, anti-inflammation, inhibition of iron death, reduction of lipogenesis, up-regulation of autophagy, modulation of intestinal flora, and reduction of bile acid metabolism were summarized in this paper, so as to provide insights for in-depth research on improving NAFLD. Reference | Related Articles | Metrics

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Establishment of Lu'an Guapian Green Tea Brewing Control Chart ZHAO Xiaoyi, CHEN Aini, JIANG Qing, ZHAO Lei, QIU Tong, FANG Wanxin, LIANG Chuyun, SHARIPOVA Alina, DAI Qianying Journal of Tea Science    2024, 44 (1): 133-148.   DOI: 10.13305/j.cnki.jts.2024.01.012 Abstract （289）      PDF（pc） （2403KB）（160）       Knowledge map    Save The Coffee Brewing Control Chart is widely used in the coffee industry. According to the evaluation indices of coffee, this study applied extraction yield (EY) and total dissolved solids (TDS), which represent flavor balance and strength respectively, as quality indices to evaluate Lu'an Guapian green tea (LAGP) infusion. The optimum range of EY and TDS which yielded the maximum consumer acceptance were estimated by survival analysis. EY ranged from 2.53% to 4.57%, and TDS ranged from 0.14% to 0.28%. The LAGP Brewing Control Chart was established regarding the optimum range as the “ideal” zone. The chart was verified by both consumers and experts. This study indicates that when tea to water ratios (g∶mL) ranged from 1∶30 to 1∶15, brewing temperature ranged from 85 ℃ to 100 ℃, regulating brewing time of the first, second and third infusion less than 33 s, 15 s and 13 s, respectively, the ideal infusion can be gained. The study scientifically provided theory basis for guiding green tea brewing like LAGP. Reference | Related Articles | Metrics

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Study on the Glycosidically Bound Volatiles and Aroma Constituents in the Processing of Wuyi Rougui WU Zongjie, OU Xiaoxi, LIN Hongzheng, YU Xinru, CHEN Shouyue, WU Qingyang, LI Xinlei, SUN Yun Journal of Tea Science    2024, 44 (1): 84-100.   DOI: 10.13305/j.cnki.jts.2024.01.005 Abstract （284）      PDF（pc） （1428KB）（387）       Knowledge map    Save ‘Rougui’, the main cultivar of Wuyi rock tea, is characterized by a rich floral and pungent cinnamon aroma. To elucidate the contribution of key aroma constituents and glycosidically bound volatiles (GBVs) to Wuyi Rougui rock tea, this study employed ultra-high-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF/MS) and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) to investigate the dynamic changes of GBVs and aroma constituents during the processing of Wuyi Rougui rock tea. The results reveal that a total of 276 aroma constituents were identified from 11 different processing stages of Wuyi Rougui rock tea. These aroma constituents belong to various chemical classes, including esters, alcohols, heterocyclic constituents, ketones, aldehydes and terpenes, with heterocyclic constituents, esters, terpenes and alcohols being the predominant aroma components. Orthogonal partial least squares-discriminant analysis (OPLS-DA) identified 35 characteristic aroma constituents in Wuyi Rougui rock tea, as indicated by their Variable Importance in Projection (VIP) values and Odor Activity Values (OAV) greater than 1. Notably, the contents of constituents associated with green and grassy flavor, such as (Z)-3-hexen-1-ol, (E)-2-nonenal and hexanal, exhibited decreasing trends during the processing, while aroma constituents associated with floral or fruity aromas, like linalool, benzyl alcohol, benzaldehyde, eugenol and β-ocimene, displayed increasing trends. Furthermore, in fresh leaves of Wuyi Rougui rock tea, aroma constituents including linalool, benzyl alcohol, benzaldehyde, 2-ethoxy-3-methylpyrazine and (E,E)-3,5-octadien-2-one exhibited ACI values greater than 1, suggesting they are key aroma constituents during the processing of Wuyi Rougui rock tea. Constituents such as dehydrocinnamyl alcohol and α-ionone contributed to the characteristic cinnamon aroma of Wuyi Rougui rock tea. In addition, ten GBVs were identified. During the processing, the contents of glucosides showed an upward trend, while primeveroside showed trend. The total contents of GBVs remained relatively stable. During the late stages of fermentation, both GBVs demonstrated declining trends, particularly constituents like benzyl primeveroside, 2-phenylethyl primeveroside, geranyl glucoside, linayl primeveroside and benzyl glucoside. The results indicate that GBVs were involved in the development of the faint scent and floral-fruity notes of Wuyi Rougui rock tea. This study clarified the role of characteristic aroma constituents and GBVs in the aroma formation of Wuyi Rougui rock tea, in order to better improve the aroma quality of Wuyi Rougui rock tea. Reference | Related Articles | Metrics

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Research Progress in the Residue Analysis and Risk Assessment of Chiral Pesticides in Tea HU Yue, NING Yating, LI Hongxia, LUO Fengjian, YIN Rongxiu, ZHANG Xinzhong Journal of Tea Science    2024, 44 (3): 363-385.   DOI: 10.13305/j.cnki.jts.2024.03.013 Abstract （276）      PDF（pc） （902KB）（381）       Knowledge map    Save Chiral pesticides have one or more enantiomers, and their biological activity, toxicity, environmental behavior, degradation and metabolism may be different. Tea, as one of the three major beverages, has attracted much attention in terms of quality and safety. However, more attention is currently paid to the total amount of pesticide racemate residues. With the development of analytical techniques, it is particularly crucial to fully understand the stereoselective behavior of the chiral pesticide enantiomer in tea, as well as to examine residue degradation in tea and to set the maximum residue limits for enantiomers. This would help to improve the efficacies of chiral pesticides and reduce their residues and toxicities to non-target organisms. In this paper, the current status of chiral pesticide separation and residue detection technology in tea were reviewed, such as liquid chromatography, gas chromatography and supercritical fluid chromatography. In addition, it provided a summary of the residue degradation behaviors and risk assessment of chiral pesticide enantiomers in tea, which would be useful as a guide for further in-depth studies on chiral pesticide enantiomers in tea. Reference | Related Articles | Metrics

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Physiological Differences and Expression Analysis of Wax Synthesis Related Gene WSD1 in Tea Roots Treated with Fluorine SONG Bo, JIA Peining, YE Wenqi, WU Jun, SUN Weijiang, XUE Zhihui Journal of Tea Science    2024, 44 (2): 219-230.   DOI: 10.13305/j.cnki.jts.2024.02.010 Abstract （275）      PDF（pc） （3895KB）（373）       Knowledge map    Save Tea plant, as one of the plants with high fluorine contents, has fluoride-polymerizing property. In this paper, based on scanning electron microscopy, the roots of ‘Huangdan’ and ‘Foshou’ were treated with different fluoride concentrations (10 mg·L-1 and 50 mg·L-1) and different time periods (1 d and 16 d). The differentially expressed gene WSD1 of tea wax synthesis under fluoride treatment was screened from the transcriptome data of our research group. The results show that under 50 mg·L-1 fluoride treatment, the epidermal cells of ‘Huangdan’ root had slightly more wax on the surface and relatively loose cell arrangement, while the epidermal cells of ‘Foshou’ root had blurred boundaries, significantly more wax on the surface, and fluorine intolerance symptoms such as cell wall distortion and breakage. Quantitative fluorescence results of WSD1 related to wax synthesis show that WSD1 had a significant up-regulation effect on the wax content of tea root under exogenous fluoride treatment. The prediction results of WSD1 protein interaction network and correlation analysis show that WSD1 was negatively regulated by CSS0041298, CSS0012327 and CSS0049082. This study provided a theoretical reference for alleviating fluorine stress in tea plants from the perspective of the interaction between tea plants and wax synthesis, and provided a scientific basis for further exploring the regulation of fluorine absorption in tea plants and the breeding of fluorine-tolerant tea cultivars. Reference | Related Articles | Metrics

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The Effect of Organic Management on Soil pH in Tea Gardens SHEN Xingrong, WANG Qiuhong, HU Qiang, WANG Donghui, FU Shangwen, HAN Wenyan, LI Xin Journal of Tea Science    2024, 44 (2): 261-268.   DOI: 10.13305/j.cnki.jts.2024.02.011 Abstract （267）      PDF（pc） （311KB）（436）       Knowledge map    Save Soil excessive acidification is one of the main problems affecting the sustainable and healthy development of tea industry. To understand the long-term impact of organic management on soil pH of tea gardens, this study selected both soil samples from organic and conventional tea gardens in 84 tea producing counties of 18 provinces in China. The organic tea garden was managed organically from 1 to 21 years. The results show that the mean soil pH in organic tea gardens was significantly increased by 0.36, compared to the conventional tea gardens. With the increase of the years under organic management, the overall pH of tea garden soil shows a significant rise, and then a stable trend. The soil pH under organic management for 1-5, 6-10, 11-15 and 16-21 a significantly increased by 0.48, 0.23, 0.28 and 0.30, respectively compared to those in conventional tea gardens. The organic management also helped the soil pH towards the direction for most suitable growth and development of tea plants, the proportion of soils with pH 4.5-5.5 was only 41.9% in conventional tea gardens, it was increased to 53.1%、48.9%、58.7% and 66.7% in tea gardens under organic management for 1-5, 6-10, 11-15 and 16-21 a, respectively. These results indicate that organic management could not only overcome soil over acidification, but towards to the direction of the most suitable soil pH for the growth and development of tea plants. Reference | Related Articles | Metrics

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Chemical Composition Analysis of Unique ‘Rattan Tea’ in Yunnan FANG Chenggang, YANG Gaozhong, YANG Yingbiao, ZHANG Liqiu, CHEN Xia, LI Lianchao, LÜ Haipeng, LIN Zhi Journal of Tea Science    2024, 44 (2): 299-315.   DOI: 10.13305/j.cnki.jts.2024.02.009 Abstract （263）      PDF（pc） （2075KB）（374）       Knowledge map    Save ‘Rattan tea’ is a unique tea in Yunnan, named after the distinctive cultivation method developed by local tea farmers over generations which prompts tea tree trunks to resemble rattan in appearance. To investigate the impact of the ‘rattan tea’ pluck management system on tea quality, the one bud and two leaves from rattan tea plantation were collected to produce sun-dried tea, black tea and white tea, and the samples of the same kind of fresh leaves of the modern tea plantation were used as the control. These samples were used for the sensory evaluation and chemical composition analysis. The study shows that the sun-dried tea made from fresh rattan tea leaves exhibits a higher refreshing aroma and stronger taste, while the white tea has a stronger aroma and sweeter taste. In contrast, the black tea from modern tea gardens is characterized by a higher level of sweet aroma and a refreshing taste. The total catechin content in rattan tea was significantly lower than that in modern tea plantations, particularly in rattan white tea (67.11 mg·g-1), which was significantly lower than that of modern tea plantation white tea (84.19 mg·g-1). The content of theanine in rattan sun-dried tea (16.79 mg·g-1) was significantly higher than that in modern tea plantation sun-dried tea (14.69 mg·g-1). Both rattan sun-dried tea and rattan white tea exhibited lower phenol-to-amino acid ratios. A total of 205 primary metabolites were identified, with rattan white tea accumulated a richer profile of sugars. In addition, a total of 127 volatile compounds were detected in all tea samples. Alcohols and esters were the predominant volatile components in different tea types, with rattan white tea exhibiting significantly higher total volatile compound content than modern tea plantation white tea. Rattan black tea contained a higher content of geraniol, while modern tea plantation black tea had higher levels of linalool. In summary, the processing methods of sun-dried tea and white tea were found to be more conducive to obtain high-quality rattan tea products, and the overall chemical quality of tea samples made from rattan tea plantation were better than that of tea samples from modern tea plantation. Reference | Related Articles | Metrics

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Identification of CAB Gene Family and Excavation of Key Genes Related to Leaf Yellowing Variationin Tea Plants (Camellia sinensis) ZHONG Sitong, ZHANG Yazhen, YOU Xiaomei, CHEN Zhihui, KONG Xiangrui, LIN Zhenghe, WU Huini, JIN Shan, CHEN Changsong Journal of Tea Science    2024, 44 (2): 175-192.   DOI: 10.13305/j.cnki.jts.2024.02.007 Abstract （262）      PDF（pc） （2408KB）（390）       Knowledge map    Save Members of the light-harvesting chlorophyll a/b binding protein (CAB) gene family play an important role in plant leaf yellowing variation. In this study, the CAB family members were identified from tea plant ‘Tieguanyin’ genomic data. The bioinformatics and expression patterns were analyzed. Furthermore, the expression patterns of the CABs gene were analyzed by gene cloning and qRT-PCR in tea cultivars with different leaf colors. The key CAB genes related to tea yellowing were screened by correlation analysis of leaf color parameters and chlorophyll SPAD values. The results show that 25 members of the CAB gene family were identified, their amino acid length ranged from 167-337 and the protein molecular weight ranged from 18.5-37.1 kDa. Most CAB members were stable and hydrophobic proteins, and distributed in chloroplast by the subcellular localization prediction. According to the evolutionary relationship, CAB family members are divided into 13 subfamilies, and the Lhcb1 subfamily has the most members. Cis-acting element analysis of promoter shows that CAB family members have a lot of light-responsive elements, as well as other elements related to growth and development, hormone response, and adversity stress. The members of Lhcb1 subfamily were cloned from tea plants, CAB1, CAB6, and CAB7 genes were screened by sequence alignment. The expression analysis shows that CAB1, CAB6, and CAB7 genes had tissue expression characteristics with higher expression levels in buds, leaves and fruits, and could respond to various stresses. Finally, the qRT-PCR indicates that the expressions of CAB1, CAB6, and CAB7 genes were consistent in the yellow and green leaves. Compared with green leaves, the expression of CAB genes in yellow leaves were significantly down-regulated. The correlation analysis of gene expressions and related leaf color parameters shows that the gene expressions of CAB1, CAB6, and CAB7 were significantly correlated with leaf color parameters a, b, L, and chlorophyll SPAD values (P<0.01). Among them, the expression of CAB1 shows the highest correlation coefficient. The subcellular localization analysis shows that CAB1 was distributed in the nucleus, cytoplasm, and chloroplasts. The studies analyzed the basic characteristics of CAB family members in tea plants and the key genes related to tea color variation were identified, which provided a theoretical basis for the molecular regulation mechanism of tea color variation. Reference | Related Articles | Metrics

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Inductive Effect and Mechanism of EGCG on Beiging of White Adipose Tissue in High-fat Diet-fed GK Rats WAN Liwei, ZENG Hongzhe, PENG Liyuan, WEN Shuai, LIU Changwei, BAO Sudu, AN Qin, HUANG Jian'an, LIU Zhonghua Journal of Tea Science    2024, 44 (1): 119-132.   DOI: 10.13305/j.cnki.jts.2024.01.008 Abstract （261）      PDF（pc） （1738KB）（227）       Knowledge map    Save The types of adipose tissue are closely related to human metabolism. Transforming white adipocytes into thermogenic beige adipocytes through dietary or nutritional interventions is a safe strategy to reduce fat accumulation and regulate metabolism. Currently, research on the role of white adipose tissue beiging has mainly focused on obese populations. To explore the effect of EGCG on promoting the beiging of white adipose tissue in non-obese individuals with metabolic disorders and its related mechanisms, this study used non-obese, spontaneously diabetic type 2 GK rats. These rats were fed a high-fat diet and received 40 mg·kg-1 and 80 mg·kg-1 EGCG daily by gavage. In this study, we assessed body weight, food intake, cellular morphology of adipose tissue, gene expression levels associated with beiging, and protein expression levels of UCP1 in GK rats. Additionally, transcriptome sequencing was also performed on epididymal white adipose tissue. The results show that gavage intervention with 80 mg·kg-1 EGCG has no significant effect on the food intake and body weight of GK rats. It induced a trend of beiging in adipocytes towards a multilocular phenotype transformation, characterized by a decrease in cell size and an increase in cell number. Moreover, it significantly upregulated the expression levels of beiging-related genes Pparg, Ppargc1a, Ucp1 and the protein expression level of UCP1.This demonstrates the inducing effect of EGCG on the beiging of visceral epididymal white adipose tissue in high-fat diet-fed GK rats, indicating its potential in the regulation of lipid metabolism. Combined with transcriptome analysis, the results suggest that the induction mechanism of EGCG on the beiging of white adipose tissue in high-fat diet-fed GK rats may be associated with the PPAR signaling pathway, PI3K/Akt, and MAPK signaling pathway. Reference | Related Articles | Metrics