Longjing tea is well-known for its exceptional umami/mellow flavor, but the complexity of interactions among chemical compositions has impeded in-depth understanding. This study comprehensively compared the taste contributors in ‘Longjing 43’ (LJ43) and ‘Qunti’ (QT). Peptidomics revealed 865 identified water-soluble peptides in QT, and 497 in LJ43, with 44 umami peptides predicted. Potential umami peptide-T1R1/T1R3 complexes were further modeled using AlphaFold 3. LJ43 had higher levels of theanine (>18 mg/g), and glutamine (∼4 mg/g) compared to QT. Similar amounts of flavan-3-ols (>150 mg/g), particularly EGCG (>60 mg/g) and ECG (>30 mg/g) were determined in LJ43 and QT. Moreover, Longjing teas' characterized flavor contributions by macromolecules (peptides), and small molecules (amino acids, catechins, saccharides, and Maillard reaction products) were integrated. These insights will greatly expand tea flavor chemistry and provide promising approaches promotion premium Longjing teas. © 2025 Elsevier Ltd

Variations in cultivars and cultivation altitudes have significant impacts on tea flavour compounds however lack of comprehensive understanding. This study provided insights into differential accumulation of crucial flavour compounds in response to cultivars, cultivation altitudes, and processing. Twelve flavonoids (262.4 ∼ 275.4 mg•g−1) and 20 amino acids (AAs) (56.5 ∼ 64.8 mg•g−1) were comparative analyzed in ‘Longjing 43′ and ‘Qunti’ fresh leaves harvested at low (80 m, LA) and high (500 m, HA) altitudes. Additionally, an in-depth correlation unravelling of 31 alkaloids, 25 fatty acids, 31 saccharides, 8 organic acids, and 7 vitamins and flavonoids/AAs during green tea (GT) and black tea (BT) processing was performed. Enhenced flavonoid accumulation alongside higher AAs and saccharides in HA GT promoted a sweet/mellow flavour. Abundant flavonoids, AAs, and saccharides derivates in LA BT gave rise to a sweet aftertaste. The study presents an integrated illustration of major flavour compounds' differential accumulation patterns and their interrelations, providing new insights into the influence of cultivation conditions on tea flavour. © 2024 Elsevier Ltd

Strip/needle green teas (SGT/NGT) processed using innovative technologies are in high demand; however, mechanisms behind their color and flavor have not been comprehensively studied. We aimed to reveal the dynamics of major pigmented components (carotenoids, lipids, flavonoids, and Maillard products) and their contributions to the flavor of green teas. The total content of flavonoids in SGT and NGT were 255 +/- 4.51 and 201 +/- 3.91 mg center dot g(-1), respectively; these values are slightly lower than that in fresh leaves (FLs), resulting in a fresh and sweet aftertaste. In average, carotene content in SGT/NGT (24.8 mu g center dot g(-1)) was higher than in FL (17.4 mu g center dot g(-1)), whilst xanthophyll content (603 mu g center dot g(-1)) decreased to one-half of that in FL (310 mu g center dot g(-1)). Among the 218 primary metabolites, glutamine, glutamic acid, and arginine were found to accumulate and were dominate contributors for the umami and sweet taste. Notably, more than 96 volatiles were screened and revealed their correlations with carotenoids, lipids, and amino acids. Overall, the synergism between pigments and their non-enzymatic derivates' contribution to GT characterized flavor was illustrated.

This study investigated the effect of anaerobic treatment on the non-volatile components and angiotensin-converting enzyme (ACE) inhibitory activity in purple-colored leaf tea. Results showed that after 8 h of anaerobic treatment, the γ-aminobutyric acid (GABA) content significantly increased from 0.02 mg/g to 1.72 mg/g (p © 2024 The Authors

Intelligently processed black teas (BT) possess premium quality but there is a lack in comprehensive understanding of flavor formation mechanism. In this study, the accumulation of carotenoids, flavonoids, and Maillard products and (non)enzymatic degradations and conjugations to characterized flavors were comprehensively studied. Significant decrease was observed that flava-3-ols were heavily oxidised from > 240 mg·g−1 in fresh leaves (FL) to −1, while other 21 flavonoids decreased by −1 to 728 ± 44.9 μg·g−1) but decreased in BT. Strong correlations were confirmed between the 218 primary metabolites, carotenoids, and flavonoids, and their contributions to BT sweet tastes were elucidated. Furthermore, 45 floral/sweet volatiles with VIP > 1 originating from carotenoids, lipids, and amino acids were screened. An integrated illustration of pigments thermal- and enzymatic-dominated contributions to BT flavour was comprehensively conducted. © 2023 Elsevier Ltd

The functional components in tea confer various potential health benefits to humans. To date, several special tea products featuring functional components (STPFCs) have been successfully developed, such as O-methylated catechin-rich tea, gamma-aminobutyric acid-rich tea, low-caffeine tea, and selenium-rich tea products. STPFCs have some unique and enhanced health benefits when compared with conventional tea products, which can meet the specific needs and preferences of different groups and have huge market potential. The processing strategies to improve the health benefits of tea products by regulating the functional component content have been an active area of research in food science. The fresh leaves of some specific tea varieties rich in functional components are used as raw materials, and special processing technologies are employed to prepare STPFCs. Huge progress has been achieved in the research and development of these STPFCs. However, the current status of these STPFCs has not yet been systematically reviewed. Here, studies on STPFCs have been comprehensively reviewed with a focus on their potential health benefits and processing strategies. Additionally, other chemical components with the potential to be developed into special teas and the application of tea functional components in the food industry have been discussed. Finally, suggestions on the promises and challenges for the future study of these STPFCs have been provided. This paper might shed light on the current status of the research and development of these STPFCs. Future studies on STPFCs should focus on screening specific tea varieties, identifying new functional components, evaluating health-promoting effects, improving flavor quality, and elucidating the interactions between functional components.

Carotenoids differentiate among tea cultivars and play role in contributing aroma flavor and colour appearance in tea products. In this study, 3 carotenes and 16 xanthophylls were accurately quantified of 0.79–1.56 × 103 μg g−1 in 15 tea cultivars possessing leaves of different colours. Lutein and β-carotene accounted for >80% of total carotenoids. Single carotenoid accumulation patterns and their correlations with chlorophylls and primary metabolites (amino acids, alkaloids, and saccharides) were elucidated. Tea processing (withering, ‘kill-green,’ fermentation, and drying processes) decreased tea carotenoids by >65%, promoting volatile apocarotenoid production. In total, 25 crucial carotenoid-derived aroma compounds were detected in green, white, and black teas prepared from purple shoots. Additionally, α/β-ionone and their derivates, and dihydroactinidiolide accounted for >50% of total volatiles and therefore explained the fruity aroma in purple tea products. A comprehensive integrative analysis of sensory attributes and volatile and carotenoid precursor dynamics clearly revealed patterns of tea carotenoid accumulation and degradation contribution to tea aroma. © 2022

In this study, we produced roasted, baked, steamed, and sun-dried green tea products using the same batch of fresh tea leaves (FTL) of Longjing 43 (Camellia sinensis var. sinensis), and explored processing effects on the metabolic profiles of four types of green teas (FGTs) using the widely targeted metabolomics. Results showed that 146 differential metabolites including flavonoids, amino acids, lipids, and phenolic acids were screened among 1034 non-volatiles. In addition, nineteen differential metabolites were screened among 79 volatiles. Most of nonvolatiles and volatiles metabolites changed notably in different manufacturing processes, whereas there were no significant differences (p>0.05) in the levels of total catechins between FGTs and FTL. The transformation of metabolites was the dominant trend during green tea processing. The results contribute to a better understanding of how the manufacturing process influences green tea quality, and provide useful information for the enrichment of tea biochemistry theory.

针对当前茶叶加工的数字化和智能化水平偏低，精制工艺与工程装备不配套等突出问题，系统开展了针芽形绿茶和条形绿茶自动化加工关键参数研究，在此基础上，研制智能摊青模块、智能杀青模块、智能揉捻模块等关键设备，开发出智能化生产线的数据采集与监控系统(SCADA);构建针芽形绿茶和条形绿茶初制精制智能化成套设备 2 套，茶鲜叶处理能力≥400公斤/小时，工艺单元具备主要参数实时采集、故障诊断与自动监控等功能，实现了数字化集成控制，并在浙江、湖南、湖北、海南、江西等具有地理标志保护的茶叶主产区进行试验考核和示范推广，取得了显著成效，为实现我国茶叶的标准化、数字化和智能化加工奠定了良好的基础。In view of the low digital and intelligent level of tea processing and the mismatch between refining process and engineering equipment,this project has systemic studied the crucial parameters of automatic processing of needle bud green tea and strip green tea.Base on this,intelligent fresh leave spreading module,intelligent killing green module,and intelligent rolling module have been developed.Moreover,the data acquisition and monitoring system(SCADA)of intelligent green tea production line has been developed.Two sets of intelligent complete sets of equipment for processing and refining of needle bud green tea and strip green tea are constructed,with the processing capacity of fresh tea leaves ≥ 400 kg/h.The process units have the functions of real-time acquisition of main parameters,fault diagnosis and automatic monitoring,which realize digital integrated control.Till moment,it has been applied in Zhejiang,Hunan,Hubei,Hainan Jiangxi and other major tea producing areas where geographical indication protection.Demonstration and extension of these green tea intelligent production lines have achieved remarkable results,which has laid a good foundation for the standardization,digitization and intelligent processing of tea in China.

采用来自湖北宣恩的鄂茶10号嫩芽材料,按照不同的做形方式（烘条、理条、滚条、搓条）和理条叶含水量（含水量40%、37%、33%、30%）加工成干茶,采用感官评价和理化测定对茶叶的外形和主要成分进行分析,探究不同做形方式对茶叶品质的影响,从而得出条形名优绿茶的最适做形方式。结果显示,不同做形方式影响茶叶形状品质,理条与搓条做形评分都显著高于烘条和滚条做形处理,不同做形方式对干茶和茶汤色泽影响显著。综合各项因素,理条做形外形条索紧结优美,综合品质最好。随着理条叶含水量的降低,茶叶条索变得紧直,香气浓度提高,但干茶和叶底绿色度和润度明显下降,色泽变暗;叶绿素总量和叶绿素a含量显著下降,氨基酸含量增加,茶多酚、可溶性糖和叶绿素b含量变化不明显。综合感官评价和理化指标分析,理条做形以理条后叶子含水量在33%～37%为宜。