Environmental pollutants are important exogenous factors inducing oxidative stress in humans. Fine particulate matter, heavy metals and other pollutants enter the human body and trigger oxidative stress by inducing excessive generation of reactive oxygen species. This impairs mitochondrial function and activates inflammatory signaling pathways, which subsequently contribute to the development of various chronic diseases. Tea polyphenols, as the primary antioxidant components in tea, can directly scavenge free radicals, activate the Nrf2/ARE signaling pathway, inhibit pro-oxidant enzyme activity, protect mitochondria and block the inflammation-oxidative stress vicious cycle, thereby alleviating oxidative damage. This paper reviewed the classification of common environmental pollutants and the mechanisms by which they induce oxidative stress in humans, systematically analyzed the pathways through which tea polyphenols mitigate oxidative stress and their protective effects at the cellular, organ and systemic levels, and elucidated the application value of tea consumption and tea polyphenol-related products in counteracting health risks associated with environmental pollution.

Polyphenols possess abundant active structures that can form a stable network with matrix materials through multiple molecular interactions, making them suitable for the preparation of multifunctional composite materials with properties such as adhesion, self-healing, antibacterial, antioxidant, chromogenic response, and conductive sensing. In this work, the effects of polyphenol structures on material performances were reviewed. Dominant fabrication strategies including blending, electrospinning and layer-by-layer self-assembly for wearable polyphenol-based sensing materials, together with their technical characteristics, were summarized. Research advances of the as-prepared sensing materials in human motion monitoring and wound healing surveillance were also concluded. It was pointed out that continuous film-forming, multimodal signal integration, intelligent recognition and low-cost green manufacturing technologies were regarded as key research directions in future studies. Industrial applications of wearable polyphenol-based sensing materials were further promoted through the exploration of the above technologies.

Tea polyphenols are rich in phenolic hydroxyl groups, and possess excellent antioxidant and antibacterial activities, making them suitable for use as natural active additives in the fabrication of biodegradable composite films. In this paper, the physicochemical properties of tea polyphenols, mainstream preparation techniques of composite films (solution casting, electrospinning, layer-by-layer self-assembly, etc.) and their application advances in fruit preservation as well as the storage of meat and aquatic products were reviewed. It was demonstrated that the lipid oxidation and protein deterioration of fresh foods could be effectively inhibited by tea polyphenol composite films, and the shelf life was markedly prolonged. However, several drawbacks were found in such films: uneven release of active components, easy structural failure under high humidity, weak interlayer bonding force and relatively high preparation cost. It was suggested that future studies could integrate arti ficial intelligence calculation, molecular simulation and machine learning and that a formula database of tea polyphenol composite films could be created to enable targeted and precise design of the films and promote iterative upgrading of packaging materials for fresh food preservation.

Various bioactive constituents in tea have been found to possess favorable reduction, coordination, biocompatibility and interfacial properties, making them ideal nanocarriers for preparing drug delivery nanomaterials. On the basis of reviewing the performances and drawbacks of primary tea-derived bioactive substances, the reaction mechanisms, technical features of dominant fabrication approaches including in situ growth, coordination self-assembly, blending crosslinking and electrostatic assembly were summarized in this paper, together with the applications of resultant nanocarriers in enhancing ingredient stability as well as realizing sustained, controlled and targeted drug delivery. It was proposed that fabrication procedures, targeted modification and stimuli-responsive design should be further optimized to promote the industrialized application of tea-based nanomaterials in drug delivery.

α-Farnesene, a key sesquiterpene, modulates aroma quality and stress response in tea plants. α-Farnesene synthase (AFS), the rate-limiting terminal enzyme in its biosynthetic pathway, serves as a core molecular hub linking terpenoid metabolism, stress-resistant breeding, and quality regulation in Camellia sinensis. Based on the terpenoid secondary metabolic network of tea plants, this study systematically reviewed the cloning, identification, expression patterns, and biological functions of the α-farnesene synthase gene (CsAFS) in Camellia sinensis. It further described the synergistic regulatory network composed of transcription factors, phytohormones and environmental signals, and clarified the scientific implications and intrinsic crosstalk mechanisms of tea-specific regulatory modules involving CsAFS. Through cross-species comparative analysis, this paper revealed the evolutionary conservation and species-specific characteristics of CsAFS, and comprehensively dissected its biological roles in stress response, aroma formation and quality regulation. Meanwhile, potential applications of CsAFS in stress-resistant breeding, ecological tea garden construction, and tea processing quality improvement were discussed. In view of current research gaps, such as incomplete functional characterization of gene family members, immature genetic transformation systems, and insufficient compatibility between regulatory strategies and practical tea production, future research priorities were proposed based on cutting-edge advances in tea science. This study aimed to provide theoretical foundations for stress-resistant breeding, ecological cultivation, and quality improvement in tea plants.

Salicylic acid (SA) is a naturally occurring phenolic compound in plants, functions as a key component in signaling pathways that activate and precisely modulate the defense response against pests and diseases. In plants, SA is predominantly synthesized through the isochorismate synthase and phenylalanine ammonia-lyase pathways. SA can undergo diverse modifications in plants, such as hydroxylation, glycosylation and methylation, which contribute to SA storage and signal transduction. Activation of the SA signaling pathway significantly reprograms secondary metabolism of plants, consequently enhancing plant resistance. Tea plants (Camellia sinensis) exhibit relatively high endogenous SA content in leaves, with values ranging from 6.9 to 41.4 μg·g^-1. This review summarized the latest research progress on tea plants, specifically focusing on the biosynthesis of SA, SA derivatives, and SA-mediated resistance. The issues in the existing research and the focuses of future research were also discussed. This review provided a reference for the in-depth exploration of the role and mechanism of SA in regulating the disease and pest resistance of tea plants and the development of novel green control technologies.

Tea anthracnose, a foliar pathological damage caused by Colletotrichum spp., is widely distributed in the mountainous tea gardens of Southwest China and the Jiangnan region. The disease is most severe in spring and autumn, significantly impacting tea yield and quality. This paper comprehensively reviewed the pathogen biology, disease symptoms, epidemic patterns, and control technologies of tea anthracnose, with particular emphasis on recent advances in agricultural, chemical, and biological control strategies. Furthermore, prospects for sustainable and environmentally friendly management approaches were discussed.

Nitrogen (N) is an essential macronutrient for plant growth and development, and has been the subject of significant research. In recent years, breeding plants with high nitrogen use efficiency (NUE) has become a prominent focus, both theoretically and practically. However, compared with the remarkable research progress achieved in staple food crops such as rice and wheat, little systematic research has been conducted into cash crops. Tea plant (Camellia sinensis) is an important cash crop, with its economic benefits primarily derived from vegetative organs (buds and leaves). Nitrogen plays a crucial role in the growth, morphology, and quality formation of tea leaves. This paper reviewed the effects of nitrogen on tea plant growth and quality, summarized research progress on nitrogen-efficient tea plants from the perspectives of physiological processes, molecular regulatory mechanisms, and genetic foundations, outlined screening criteria for nitrogen-efficient tea cultivars, and provided future research directions.

The unique characteristics of γ-amino butyric acid (GABA) tea as a functional food resource have made it a popular healthy beverage and a hot topic in research. This paper reviewed the common strains of microbial fermentation of GABA tea, the research status and application technology of microbial fermentation of GABA tea, and the effects of metabolites on the quality and physiological health effects of GABA tea. Meanwhile, the future research and development of microbially fermented GABA tea were also prospected.

As a traditional agricultural planting model, intercropping in tea gardens introduces other plant species into the tea garden ecosystem to construct a complex tea garden ecosystem. It has various positive effects on improving the species diversity and stability of the tea garden ecosystem, as well as increasing the yield and quality of tea. To systematically evaluate the comprehensive impact of intercropping on the tea garden ecosystem, this paper integrated relevant research in recent years. Firstly, the types and main functions of intercropping in tea gardens were classified and analyzed. Secondly, the focus is on analyzing the impacts of intercropping on multiple dimensions such as micro-climate, soil environment, growth and metabolism of tea plants, regulation of diseases, pests and weeds, and carbon sequestration and emission reduction in tea gardens, in order to clarify the suitable intercropping types and specific regulatory mechanisms. Through this study, the mechanism and effects of intercropping in tea gardens on tea production were systematically elucidated, with the aim to provide a theoretical basis for the construction of high-quality and high-yield tea gardens and the green and sustainable development of the tea industry, and to offer ideas and references for future research directions.

Alkaloids, as a class of nitrogen-containing secondary metabolites characterized by remarkable chemical diversity, are widely distributed in higher plants, fungi, and bacteria. Most natural alkaloids possess biological activities such as antioxidant, anti-inflammatory, and anti-tumor effects. This review comprehensively summarized the identified alkaloid groups in tea and briefly analyzed their biological activities, including: (1) purine alkaloids, which regulate neural excitability by antagonizing adenosine receptors and inhibiting phosphodiesterase to regulate metabolic functions, exhibit anti-inflammatory, and other biological activities. (2) flavor alkaloids have effects in preventing diabetes and inhibiting cancer cell angiogenesis. (3) the mechanisms by which prenylated indole alkaloids exert anti-inflammatory effects, inhibit cancer cell growth and exert neuro-protective effects. Finally, the future research directions focusing on the identification, appraisal, synthesis and functional evaluation systems of tea alkaloids were proposed.

Nitrogen metabolism genes play a key role in tea plants′ response to various environmental stresses. They do this mainly by regulating metabolites in different pathways. In recent years, significant progress has been made in the study of nitrogen metabolism genes in tea plants using techniques such as transcriptome and metabolome analysis, genome identification. However, there are still many scientific problems that need to be solved urgently, such as the low genetic transformation efficiency of tea plants, the limited research on gene epigenetics, and the limited application of gene breeding in production. This article systematically summarized the expression patterns of nitrogen metabolism genes in tea plants under different stress conditions, organs, and soil elements, as well as the research progress on the regulation mechanism of carbon and nitrogen balance in tea plants under different stresses, revealing the importance of these genes in tea plant stress adaptation and quality improvement. In addition, the research methods, transgenic technology, and breeding applications of nitrogen metabolism genes in tea plants were discussed in order to provide reference for the study of nitrogen metabolism gene regulation mechanisms and breeding research in tea plants.

Qingzhuan brick tea, as one of China’s characteristic brick-shaped dark tea mainly produced in Xianning city of Hubei Province, is widely favored by consumers for its unique sensory characteristics and health benefits. Focusing on the quality of Qingzhuan brick tea, this paper reviewed its sensory characteristics, main active components and health effects, as well its main influencing factors. It also prospected the future product development and research directions of Qingzhuan brick tea, in order to provide a reference for the diversified development of Qingzhuan brick tea products and personalized precise nutrition research, and promote the development of Qingzhuan brick tea processing and storage technology in the direction of modernization and intelligence.

Tea polyphenols are the most abundant active components in tea, with a variety of physiological functions. However, there is a lack of a systematic summary regarding the research history of tea polyphenols. This paper systematically reviewed the discovery, naming and functional application of tea polyphenols, while also briefly discussed their health benefits in immune regulation, anti-inflammation, and oxidative stress as well as the structural basis of the active hydroxyl groups in polyphenols. Consequently, it provided support for the application research of tea polyphenols in different fields. In addition, in view of the problems of poor stability and low bioavailability of tea polyphenols, we provided a brief overview of research on novel tea polyphenol nanobiomaterials. These nanobiomaterials exhibited the characteristics of high stability, safety and multi-functionality, which were anticipated to enhance the further application of tea polyphenols.

During the processing of tea beverages, a considerable amount of foam is generated, which adversely affects the quality, stability, and appearance of the products and is a major challenge for the industry. Proper understanding and management of the causes of foam generation and control technologies are critical to optimizing the production process. This article systematically examined the fundamental theory of foam generation and analyzed the impact of various factors such as tea components, temperature and pH levels on this process. Additionally, it outlined different methods for foam elimination, discussed defoaming principles, and categorized commonly used anti-foaming agents in the food industry, intending to provide valuable references for optimizing tea beverage processing technology.

Withering is an important process for tea quality formation. Fresh tea leaves are subjected to a variety of environmental stresses such as water loss, temperature, light and mechanical damage during withering. Under these stresses, complex physiological and biochemical changes in leaves, which ultimately contribute to the formation of tea quality. This paper reviewed the effects of different environmental stresses on the formation of tea taste and aroma during the withering process. It mainly analyzed how different environmental stresses regulate the synthesis and metabolism of compounds in fresh tea leaves, and further explored their effects on the changes in cellular physical structure, enzymatic, and non-enzymatic chemical reactions in fresh tea leaves. This review provided theoretical supports for improving tea quality.

Tea waste and summer-autumn tea can be used to produce Kombucha and bacterial cellulose, helping to reduce environmental pollution and resource waste while developing high market value products. Bacterial cellulose, as a highly crystalline and sustainably renewable polysaccharide, has a wide range of potential applications in biomedicine, eco-friendly packaging, textiles, new energy batteries, skincare products, and other fields. This paper reviewed recent research on the applications of bacterial cellulose membranes, focusing on the effects of different fermentation environments and tea types on the quality of bacterial cellulose membranes. It confirmed that adjusting fermentation parameters can produce cellulose with specific crystalline structures. The paper also discussed the role of tea components in the formation of bacterial cellulose membranes and proposed new ideas for improving the yield and quality of Kombucha bacterial cellulose membranes. The health benefits of Kombucha bacterial cellulose membranes and their significant role in sustainable product development were emphasized. The paper highlighted the need for further research to promote their industrial application.

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.

Tea withering or drying with solarization is beneficial to save a lot of energy cost and contribute to the unique flavor formation. In this paper, the advances of solarization tea were reviewed from the aspects of flavor quality characteristics, flavor chemical characteristics, technical and environmental factors affecting their formation. Linalool, geranyl, 1-octene-3-ol and capric aldehyde are the key aroma components of solarization tea, among which 1-octene-3-ol and 1-octene-3-one may be related to sun exposure flavor. Reasonable use of environmental factors such as sunlight and air humidity is a basic requirement for processing high-quality solarization tea. On this basis, the development of technology upgrading and theoretical research for solarization tea was prospected from the technical, theoretical and industrial levels.

Tea is an important economic crop in traditional Chinese agriculture, with a long history and rich cultural connotation. The different parameters of tea origin, storage time and processing method determine the quality, nutritional value and market positioning. Known as a newly developed non-destructive testing technique, GC-IMS can analyze the volatile organic compounds (VOCs) of samples under normal pressure to characterize the differences between samples. This paper collected the existing literature data, reviewed the applications of GC-IMS technology in the study of kind differentiation, grade identification, origin identification, storage time determination and processing quality control of tea, and analyzed the current problems and future prospects of GC-IMS technology in the field of tea application, and provided theoretical reference for the flavor research, process optimization, quality analysis and quality monitoring of tea.

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.

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.

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.

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.

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.

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.

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.

Tea, as a hobby drink, the flavor is its first quality attribute. The presentation of its taste is the comprehensive perception effect of the human taste organs on the flavor components in tea infusion, which is generally manifested as bitter, astringent, fresh, sweet and other sensory experiences. Among them, bitterness is the most easily perceived taste attribute, and as a crucial factor affecting the flavor quality of tea. Meanwhile, due to the bitter taste, summer and autumn tea resources are faced with the dilemma of large abandonment, resulting in a great waste of resources. Based on this, this paper reviewed the physiological basis of bitter perception and the evaluation methods of bitter taste perception. Taking green tea infusion as the main carrier, the bitter taste components of tea were systematically integrated, and the interaction effect between other taste monomers and bitter compounds, as well as the regulatory mechanism of post-treatment on the bitter taste of tea infusion were discussed. It was expected to enrich the theoretical basis of taste chemistry and clarify the flavor characteristics of bitter compounds of tea, the taste mechanism and the interaction effect between taste substances, and provide theoretical reference for promoting the high-value utilization and taste regulation of summer and autumn tea.

The growth and development of tea plants are affected by external environmental factors, and light is one of the most important factors, which can affect the growth and secondary metabolites of tea plants alone or in coordination with other environmental factors such as temperature, etc. This paper introduced the research progress of light regulation of tea plant growth and metabolic at domestic and abroad in recent years. The main points of discussion were the effects of different spectral bands, photon flux and photoperiod on tea plant growth, types and contents of metabolites. It’s mainly for clarifying the light regulated metabolic process of tea plant growth, analyzing the light regulated mechanism, and providing theoretical support for the development of light regulated metabolic technology that can be used in production practice.

Catechins are a kind of bioactive substances rich in tea, which have the functions of anti-oxidation, anti-tumor, anti-virus, anti-inflammatory and immune regulation. However, due to the high activity of phenolic hydroxyl groups, catechins are easy to lose in vitro and in vivo activities, resulting in lower bioavailability. The recent development of nanobiotechnologies is expected to solve the problem of low bioavailability of catechins through ligand design, accurate synthesis and intelligent regulation, which can expand its application in the field of life and health. In this review, a summary on the progress of catechin biomedical nanomaterials in recent years, including the anti-tumor, antibacterial, anti-inflammatory, drug delivery and anti-virus activities, was firstly made. Later, the construction and biological mechanism of catechin biomedical nanomaterials were discussed in detail. Finally, future perspectives on the design and application of novel catechin nanomaterials were provided.

Camellia sinensis (L.) O. Kuntze is a hyper fluoride (F) accumulation plant, whose F content in tea leaves is much higher than other plants, without any toxic symptoms. However, F is not an essential element for tea plant growth, and under high F stress, F affects the normal growth of plants by destroying the cell structure and inhibiting enzyme activities. In order to provide a theoretical basis for the future study of F accumulation in tea plants, the research progresses in the absorption, enrichment and accumulation/detoxification mechanisms of F in tea plants were reviewed.

The quality of tea is the embodiment of the shape and inner quality of tea, and evaluating the quality of tea quickly and accurately is essential for tea trade and processing. Sensory evaluation, composition analysis and detection, and emerging technologies are the main tea quality evaluation techniques at present. This article summarized the research progress of three major evaluation technologies in recent years, and focused on the development trend of emerging technologies. Sensory evaluation is greatly influenced by subjective factors, but combined with quantitative description and analysis can reduce the influence of subjectivity. Component analysis detection has high threshold, difficult operation, time-consuming and labor-consuming, and the results obtained are relatively accurate. Emerging technologies are simple, fast, and non-destructive, but at present they cannot achieve satisfactory accuracy. In the tea product diversification today, only multi-dimensional comprehensive utilization of multiple methods can quickly and efficiently detect the quality of tea, and provide assistance for the healthy and efficient development of the tea industry.

As one of the main measures of habitat management, reasonable intercropping of functional plants in tea garden can shade tea bushes and keep them warm, conserve water and soil, increase fertility and promote growth, as well as maintain micro-habitat stability. It also can attract natural enemies, repel pests, reduce the damage caused by diseases, insects, and weeds in tea garden, therefore it is beneficial for improving the quality and efficiency of the tea. However, unreasonable intercropping will destroy the micro-habitat of tea garden, compete for nutrients, thus affecting the growth of tea plants. In this paper, the intercropping of functional plants and their effects on the ecosystem functions and services in tea garden in recent years were reviewed. These effects mainly included the species, management models, functions and common problems with the most widely used functional plants, as well as the regulatory effects of intercropping of functional plants on the growth and development of tea plants, tea quality and yield, and tea pests. The ultimate goal of this paper was to provide guidance for the application of intercropping measures to promote the comprehensive regulation of pests in tea garden, and enhance the ecosystem functions and services of tea garden.

Tea beer is a new type of beer, obtained by adding tea or tea extract in the brewing process with the dual flavor characteristics of tea and beer. The development of tea beer would not only enrich the types, flavors, and physiological effects of beer, but also improve the utilization rate and additional value of tea resources and benefit for the common development of tea and beer industries. However, the studies of tea beer on pretreatment of raw materials, fermentation and clarification technologies were still not mature. Therefore, this paper systemically summarized the processing technologies of tea beer, including the pretreatment of raw materials, fermentation and clarification technologies. Based on that, we made the prospects for the future of tea beer, aiming to provide a reference for the research and development of tea beer in depth.

Catechin compounds, mainly including monomeric catechins and polymericcatechins, are the main components of tea polyphenols in Camellia sinensis and the decisive components of the "taste" of green tea. The synthesis and accumulation of tea catechin compounds have remarkable tissue- and organ- specificity. The leaves mainly biosynthesize monomeric catechins, and roots mainly accumulate polymeric catechins. The downstream enzymes of flavonoid metabolism pathway, leucoanthocyanidin reductase (LAR) and anthocyanin reductase (ANR) are the key enzymes determining the types of catechins. This paper mainly reviewed the research progress on the biosynthesis, accumulation, and transcriptional regulation of catechins in Camellia sinensis, with emphasis on the latest research progress in the function and transcriptional regulation of LAR, ANR and leucoanthocyanidin dioxygenase (LODX). Our views on the unsolved problems in catechin synthetic pathway were also proposed.

The tea plant has the characteristics of high heterozygosity, large genome and high duplication, which has led to the slow progress of the preliminary research on the tea plant genomes. The rapid development of genome sequencing technologies has strongly promoted the deciphering and improvement of the tea plant genomes. This article reviewed the development of genome sequencing technologies, and classified the assembly and research progress of tea plant genomes in recent years according to the draft level, chromosome level and haplotype level. By discussing the future application and development direction of tea plant genomes, it provided a reference for the functional genomics research and precision molecular breeding in tea plants.

Cocoa tea (Camellia ptilophylla Chang) is a specific tea resource in China, and theobromine (TB) and gallocatechin gallate (GCG), as the dominant chemical components of cocoa tea, have various health effects. This paper summarized intervention effects and mechanisms of cocoa tea, TB and GCG on cardiovascular diseases, cancers, obesity, diabetes, neurodegenerative diseases, dental diseases, respiratory diseases and kidney diseases, etc. This review would provide a theoretical reference for the development of functional cocoa tea products.

Aroma is one of the key indicators to evaluate tea quality, and aroma quality is formed by the complex interactions between different volatile compounds. Premium roasted green teas generally have characteristics of excellent flavor quality, and are the most typical and representative Chinese green tea. In recent years, studies on their volatile compounds had increased gradually and made good progress. However, there were very few systematic explanations on the composition characteristics in aroma compounds of diverse high-quality roasted green teas. Therefore, the present study summarized the research progression in volatile compounds of premium roasted green teas in recent twenty years, enumerated the aroma compounds, illuminated the common compounds, and further discussed the key aroma compounds. These results will provide scientific evidence for the flavor evaluation and aroma quality control for the premium roasted green tea.

Tea (Camellia sinensis) is known as a global health beverage, and global tea consumption increases due to its biological activities. In the last 30 years, antiviral activities of tea and its components, especially tea polyphenols, with different modes of action were demonstrated on diverse families of viruses, such as influenza virus, coronavirus, hepatitis virus, and human immunodeficiency virus, etc. This review summarized the current knowledge on the antiviral activities of tea and its components. Most of these studies demonstrated antiviral properties of tea and its components by in vitro biochemical or cell experiments with little rodent and clinical studies. Therefore, it is still unclear whether the antiviral effects of daily tea consumption are available. More large-scale randomized intervention and epidemiological/clinical studies are needed to confirm clinical efficacy of tea and its components.

Melanin is a kind of high molecular biological pigment. The color of skin is determined by the type and accumulation of melanin as well as the redistribution and degradation of melanosome. Solar ultraviolet radiation is the most common cause of melanin formation. Although melanin can protect skin cells from UV damage, the abnormal accumulation of melanin will lead to diseases related with melanin disorders. Therefore, the development of green, safe and efficient melanin inhibitors extracted from plants has become a research hotspot in recent years. Many studies have proved that extract or monomer compounds of tea could significantly inhibit (a) the activity of tyrosinase, (b) the growth, proliferation, infiltration and metastasis of melanocytes, (c) the occurrence of skin cancer. In this paper, the research progress of tea active compounds inhibiting melanin formation in acellular tyrosinase test system, cell test system, animal model and human skin was reviewed to fully explore the key active compounds, find a safe and efficient inhibitor of melanin synthesis and provide reference for the comprehensive utilization of tea products and increasing the added value of tea industry.