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

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.

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。

The freshness and color quality of postharvest tea leaves can be markedly prolonged and retained by proper preservation measures. Here, we investigated the dynamic changes of chlorophyll and its derivatives in postharvest tea leaves under different lowerature treatments using natural withering as a control. Chlorophyll decomposition was found closely related with chlorophyllide, pheophorbide, and pheophytin. Lowerature withering could slow chlorophyll degradation in postharvest tea leaves via significant inhibition on the enzyme activity and gene expression of Mg-dechelatase, chlorophyllase, and pheophorbide a oxygenase. At the initial stage of withering, a significant increase was observed in the chlorophyll content, expression of chlorophyll-synthesis-related enzymes (such as glutamyl-tRNA synthetase, etc.), and chlorophyll synthase activity in newly picked tea leaves. Moreover, an obvious decrease was found in the content of l-glutamate as the foremost precursor substance of chlorophyll synthesis. Hence, our findings revealed that the chlorophyll synthesis reaction was induced by the light-dehydration-stress in the initial withering of tea leaves. This study provides a theoretical basis for exploring preservation technology in actual green tea production. © 2019 American Chemical Society.