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Tea's popularity and flavor are influenced by factors like cultivation and processing methods and shaping techniques also have an impact on tea flavor. This study employed targeted metabolomics and chemometrics to investigate how shaping techniques affect the flavor of milk-flavored white tea (MFWT). The results showed that the tea cake sample with the shortest pressing time (Y90) has the highest amino acid content and milky aroma intensity. There were variations in amino acids, catechins, and soluble sugars among MFWT samples with different shaping techniques. The total contents of amino acids and catechins in tea cake sample (Y90) were significantly lower than those in the loose tea sample (SC) and bundle-like tea sample (SG), while the total sugar content was significantly higher than that in SC (P1) in Y90 remained lower relative to SC and SG (P

Wang Xufeng's "Tetralogy of Tea People" showcases traditional Chinese tea culture through his depiction of the ups and downs of a tea family, the Hang clan, in a century in Zhejiang. Firstly, as public space, the Worry-Free Tea House corresponded with China's modern and contemporary historical process, demonstrating the open, inclusive, and indomitable national spirit in tea culture. The production process of Longjing tea and tea tree flower tea symbolizes the ideal personality of being clean and independent. The Mansheng teapot is a symbol of "using objects to enlighten the way", carrying the narrative function of moving towards bright future. The line of "how can people regard tea bitter? It's as sweet as shepherd's purse in my mind" is the essence of tea, and it is also an important way for individuals to inspire their thoughts on existence and towards their true nature. [ABSTRACT FROM AUTHOR]

As one of the most consumed non-alcoholic beverages in the world, tea is acclaimed for its pleasant flavor and various health benefits. Different types of tea present a distinctive flavor and bioactivity due to the changes in the composition and proportion of respective compounds. This article aimed to provide a more comprehensive understanding of tea flavor (including aroma and taste) and the character of tea in preventing and alleviating diseases. The recent advanced modern analytical techniques for revealing flavor components in tea, including enrichment, identification, quantitation, statistics, and sensory evaluation methodologies, were summarized in the following content. Besides, the role of tea in anti-cancer, preventing cardiovascular disease and metabolic syndrome, anti-aging and neuroprotection, and regulating gut microbiota was also listed in this article. Moreover, questions and outlooks were mentioned to objectify tea products' flavor quality and health benefits on a molecular level and significantly promote our understanding of the comprehensive value of tea as a satisfactory health beverage in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • Different taste and aroma characteristics were presented in 4 white tea and their processing samples. • The maturity of fresh tea leaves was the primary factor that promoted the formation of milky flavor. • The processing method was the key to inducing milky aroma under mature fresh tea leaves conditions. Targeted metabolomics combined with chemometrics were applied to investigate the flavor profiles of 4 white tea samples, which were produced from different maturity fresh tea leaves with different withering methods. Mature leaves that underwent novel withering process at higher temperature (28-30℃) and humidity (75 ± 3 %) (MN) were characterized by intense milky flavor. The content of free amino acids, catechins, and soluble sugars in MN were significantly lower than that in the other 3 tea samples, resulting in a sweet and mellow taste with low bitterness. Meanwhile, MN possessed the highest intensity of milky aroma, which could be mainly attributed to the existence of dihydro-5-pentyl-2(3H)-furanone and 2-pentyl-furan as the key volatile substances with coconut and creamy fragrance. These findings provide insight into the substance foundations of milky flavor, and identified leaf maturity and processing method as the determining factors of the milk-flavored white tea (MFWT). [ABSTRACT FROM AUTHOR]

Copyright of Food Research & Development is the property of Food Research & Development Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Highlights • Withered tea leaves were subjected to transcriptome and metabolite profiling. • Tea leaves were intact, alive and showed active gene-expression during withering. • Dehydration triggered changes in transcription and content of tea flavor compounds. Abstract Withering is an indispensable process for improving flavors in green, black and white teas during their manufacturing. The effects of the withering process on the formation of tea flavors were investigated using transcriptome and metabolite profiling in withered tea leaves. A total of 3268, 23,282 and 25,185 differentially expressed genes (DEGs) were identified at 3 h (68%, water content), 12 h (61%) and 24 h (48%) of the withering process, respectively. The DEGs, involved in flavonoid biosynthesis were significantly downregulated, which could be correlated with the reduction of catechins. Enhancement of terpenoids and alpha-linolenic acid metabolism could trigger an increase in the total content and number of volatiles. The increase in free amino acid-content could be related to 261 DEGs. Our study suggests that dehydration stress during withering induced significant changes in the gene transcription and content of the tea flavor compounds, which promoted the special flavors in various teas. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Food Safety & Quality is the property of Journal of Food Safety & Quality Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper describes a method for developing a novel, low-cost, hand-held electronic nose (E-Nose) for black tea flavor estimation using metal–oxide–semiconductor gas sensors. In this research, a first-level experimentation has been conducted with a computer-assisted-technology-based system for sensor selection and validation. In the second level, a novel hand-held E-Nose is designed and developed for generation of tea aroma, capturing the response patterns and signal processing in a microcontroller (PIC 18F45K22) for tea flavor grading. The results of the first-level experimentation provide the sensor selection, where only four out of 12 sensors were selected based on their performance. Moreover, the classification network was predetermined for implementation in the microcontroller. Experiments conducted on the developed hand-held E-Nose show the classification on eight different grades of tea (each with ten samples) varying from 70% to 100%, revealing an average classification efficiency of 90%. The repeatability of the system was also found to be 80%. The developed system also overcomes the problem of heating the tea sample, since the volatile organic compounds of tea are generated due to the emitted heat of the sensors in the proposed system. [ABSTRACT FROM PUBLISHER]

Withering leads to the formation of high-quality flavor in black tea. This study investigated the effects of natural withering (NW), sun withering (SW), and warm-air withering (WW) on the flavor compounds of withered leaves by using target metabolomic and transcriptomic approaches. The results revealed that 4282, 4770, and 1246 differentially expressed genes (DEGs) were identified in the NW, SW, and WW samples, respectively. The expression of DEGs involved in volatile compound and flavonoid biosynthesis was the highest in the WW sample, which may be the main reason for the significant increase in volatile compound and catechin contents in the WW sample. The withering methods mainly affected the contents of non-proteinaceous amino acids, such as theanine. Withering methods significantly affect the expression levels of DEGs involved in metabolic pathways; this provides a systematic explanation for flavor formation in black tea. • Different withering methods affect the flavor formation of black tea. • The essence of the withering method is the type of stress. • Warm-air withering increased the content of flavor compounds. • Comprehensive explanation of the mechanism of action of withering method of black tea. [ABSTRACT FROM AUTHOR]

Tea is the world's oldest and most popular caffeine-containing beverage with immense economic, medicinal, and cultural importance. Here, we present the first high-quality nucleotide sequence of the repeat-rich (80.9%), 3.02-Gb genome of the cultivated tea tree Camellia sinensis . We show that an extraordinarily large genome size of tea tree is resulted from the slow, steady, and long-term amplification of a few LTR retrotransposon families. In addition to a recent whole-genome duplication event, lineage-specific expansions of genes associated with flavonoid metabolic biosynthesis were discovered, which enhance catechin production, terpene enzyme activation, and stress tolerance, important features for tea flavor and adaptation. We demonstrate an independent and rapid evolution of the tea caffeine synthesis pathway relative to cacao and coffee. A comparative study among 25 Camellia species revealed that higher expression levels of most flavonoid- and caffeine- but not theanine-related genes contribute to the increased production of catechins and caffeine and thus enhance tea-processing suitability and tea quality. These novel findings pave the way for further metabolomic and functional genomic refinement of characteristic biosynthesis pathways and will help develop a more diversified set of tea flavors that would eventually satisfy and attract more tea drinkers worldwide. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cuticular waxes changed during leaf development and dehydration or withering treatment. • Cuticular wax loading is positively correlated to tea flavor formation. • Caffeine is a major component in tea leaf cuticular wax. • Caffeine and inositol increased during dehydration or withering treatment. Despite some studies on tea leaf cuticular wax, their component changes during dehydration and withering treatments in tea processing and suspected relation with tea flavor quality formation remain unknown. Here, we showed that tea leaf cuticular wax changed drastically in tea leaf development, dehydration, or withering treatment during tea processing, which affected tea flavor formation. Caffeine was found as a major component of leaf cuticular wax. Caffeine and inositol contents in leaf cuticular wax increased during dehydration and withering treatments. Comparisons showed that tea varieties with higher leaf cuticular wax loading produced more aroma than these with lower cuticular wax loading, supporting a positive correlation between tea leaf cuticular wax loading and degradation with white tea aroma formation. Dehydration or withering treatment of tea leaves also increased caffeine and inositol levels in leaf cuticular wax and triggered cuticular wax degradation into various molecules, that could be related to tea flavor formation. Thus, tea leaf cuticular waxes not only protect tea plants but also contribute to tea flavor formation. The study provides new insight into the dynamic changes of tea leaf cuticular waxes for tea plant protection and tea flavor quality formation in tea processing. [ABSTRACT FROM AUTHOR]

As one of the most consumed non-alcoholic beverages in the world, tea is acclaimed for its pleasant flavor and various health benefits. Different types of tea present a distinctive flavor and bioactivity due to the changes in the composition and proportion of respective compounds. This article aimed to provide a more comprehensive understanding of tea flavor (including aroma and taste) and the character of tea in preventing and alleviating diseases. The recent advanced modern analytical techniques for revealing flavor components in tea, including enrichment, identification, quantitation, statistics, and sensory evaluation methodologies, were summarized in the following content. Besides, the role of tea in anti-cancer, preventing cardiovascular disease and metabolic syndrome, anti-aging and neuroprotection, and regulating gut microbiota was also listed in this article. Moreover, questions and outlooks were mentioned to objectify tea products' flavor quality and health benefits on a molecular level and significantly promote our understanding of the comprehensive value of tea as a satisfactory health beverage in the future., (Copyright © 2023. Published by Elsevier Inc.)

• Metabolites are identified that affect tea quality during five months. • Flavonoids are major differential metabolites and show specific temporal accumulation patterns. • Flavonoid-related genes expressed specifically that influenced the accumulation of flavonoids. • Structural genes involved in flavonoid biosynthesis are regulated by specific transcription factors. Flavonoids are the major class of characteristic secondary compounds in Camellia sinensis that affect quality of tea. However, the temporal variation and the underlying regulatory mechanism of flavonoid biosynthesis during different growth months require a further investigation. Here, we combined analyses of the metabolomics and transcriptomics to tea leaves freshly collected during five different months for a comprehensive understanding of flavonoid metabolism regulation in tea plants. Through loading plot analysis, significant changes in the contents of metabolites during growing months were discovered, and further co-expression and association analysis indicated that one flavone glycoside (naringenin-7-O-glucoside) and two flavonol glycosides (quercetin-3-O-galactoside and kaemferol-3-O-(6″-O-p-courmaroyl)-glucoside) were evaluated as growth markers, which may explain the high bitterness and astringency of August teas; additionally, the high levels of two flavan-3-ols (gallocatechin and catechin gallate) may contribute to the flavor formation of April tea. Meanwhile, multiple flavonoid-related structural genes, MYB and bHLH transcription factors exhibit specific expression patterns to modulate the biosynthesis of these key flavonoids. A co-expression regulatory sub-network was constructed based on profiles of differentially expressed genes; one CsbHLH and six transcription factors (three CsbHLHs and three CsMYBs) exhibited negative and positive roles in the regulation of flavonoid biosynthetic genes, respectively. Taken together, our results provide new insights into the regulation of principle flavonoids for unique flavor of tea regulated by many flavonoid-related structural genes and transcription factors during different growth months. [ABSTRACT FROM AUTHOR]

Tea-specialized metabolites contribute to rich flavors and healthy function of tea. Their accumulation patterns and underlying regulatory mechanism are significantly different under different nitrogen (N) conditions during adaptation stage. Here, we find that flavonoids associated with tea flavor are dominated by different metabolic and transcriptional responses among the four N conditions (N-deficiency, nitrate, ammonia, and nitric oxide). Nitrogen-deficiency tea plants accumulate diverse flavonoids, corresponding with higher expression of hub genes including F3H, FNS, UFGT, bHLH35, and bHLH36. Compared with N-deficiency, N-supply tea plants significantly increase proline, glutamine, and theanine, which are also associated with tea flavor, especially under NH 4 + -supply. As NH 4 , which attributes to, at least in part, efficient N transport and assimilation, and active protein degradation. A distinct divergence of N reallocation in young shoots of tea plant under different N sources contributes to diverse tea flavor.+ -tolerant species, tea plant exploits the adaptive strategy by substantial accumulation of amino acids including theanine to adapt excess NH 4 + , which attributes to, at least in part, efficient N transport and assimilation, and active protein degradation. A distinct divergence of N reallocation in young shoots of tea plant under different N sources contributes to diverse tea flavor.