Abstract:Wuyi Rock tea is one of well-known tea in China. The 'Spring Tea Competition' every year is a big event in tea industry of Wuyishan City. In this paper, 667 samples with four grades of Wuyi Rougui teas from 'Spring Tea Competition, 2019' were collected to determine quality indexes. The relationship between the quality index and tea grades was analyzed. The results showed that the higher the grade of teas, the higher the total quality score (TQS) of sensory evaluation. Most of tea quality indexes had the same t… Show more
“…Processing facilitates tea quality formation, and the contents of tea polyphenols, theanine, caffeine, amino acids, flavonoids, catechin fractions, soluble sugars, and other indexes are key in the evaluation of tea quality (Pang et al., 2022). In this study, the content of tea polyphenols, flavonoids, and catechin components in tea leaves showed a significant decreasing trend, whereas the content of theanine, caffeine, free amino acids, and soluble sugars showed a significant increasing trend as the degree of shaking and tumbling intensified.…”
Shaking and tumbling are extremely important for the formation of the special flavor of Wuyi rock tea. In this study, we analyzed the effects of different shaking and tumbling degrees on the quality index content of tea leaves and determined changes in gene expression in tea leaves using RNA sequencing technology. On this basis, the correlation between gene expression intensities in tea leaves and tea quality index content was analyzed. The results showed that heavy shaking and tumbling (MW3) increased gene expression of metabolic pathways, biosynthesis of secondary metabolites, starch and sucrose metabolism, biosynthesis of amino acids, glycine, serine, and threonine metabolism, alpha‐linolenic acid metabolism pathways and decreased gene expression of flavonoid biosynthesis, carbon fixation in photosynthetic organisms, phenylpropanoid biosynthesis, and plant hormone signal transduction pathways in tea leaves, which in turn increased the content of caffeine, soluble sugar, amino acid and decreased the content of flavone, tea polyphenol, catechin component in tea leaves; the opposite was true for light shaking and tumbling. Second, this study found that MW3 was more beneficial in improving the mellowness, sweetness, and fresh and brisk taste of tea leaves and reducing the bitterness of tea leaves. This study provides some references to guide the processing of Wuyi rock tea with different flavors.Practical ApplicationHeavy shaking and tumbling was more beneficial in improving the mellowness, sweetness, and fresh and brisk taste of tea leaves and reducing the bitterness of tea leaves. Therefore, the degree of shaking and tumbling in Wuyi production can be appropriately improved to produce high‐quality tea and improve the economic benefits of tea.
“…Processing facilitates tea quality formation, and the contents of tea polyphenols, theanine, caffeine, amino acids, flavonoids, catechin fractions, soluble sugars, and other indexes are key in the evaluation of tea quality (Pang et al., 2022). In this study, the content of tea polyphenols, flavonoids, and catechin components in tea leaves showed a significant decreasing trend, whereas the content of theanine, caffeine, free amino acids, and soluble sugars showed a significant increasing trend as the degree of shaking and tumbling intensified.…”
Shaking and tumbling are extremely important for the formation of the special flavor of Wuyi rock tea. In this study, we analyzed the effects of different shaking and tumbling degrees on the quality index content of tea leaves and determined changes in gene expression in tea leaves using RNA sequencing technology. On this basis, the correlation between gene expression intensities in tea leaves and tea quality index content was analyzed. The results showed that heavy shaking and tumbling (MW3) increased gene expression of metabolic pathways, biosynthesis of secondary metabolites, starch and sucrose metabolism, biosynthesis of amino acids, glycine, serine, and threonine metabolism, alpha‐linolenic acid metabolism pathways and decreased gene expression of flavonoid biosynthesis, carbon fixation in photosynthetic organisms, phenylpropanoid biosynthesis, and plant hormone signal transduction pathways in tea leaves, which in turn increased the content of caffeine, soluble sugar, amino acid and decreased the content of flavone, tea polyphenol, catechin component in tea leaves; the opposite was true for light shaking and tumbling. Second, this study found that MW3 was more beneficial in improving the mellowness, sweetness, and fresh and brisk taste of tea leaves and reducing the bitterness of tea leaves. This study provides some references to guide the processing of Wuyi rock tea with different flavors.Practical ApplicationHeavy shaking and tumbling was more beneficial in improving the mellowness, sweetness, and fresh and brisk taste of tea leaves and reducing the bitterness of tea leaves. Therefore, the degree of shaking and tumbling in Wuyi production can be appropriately improved to produce high‐quality tea and improve the economic benefits of tea.
“…These findings serve as a valuable reference for establishing quality standards for diverse black tea products, as well as guidance for the oriented processing of various grades of tea. A classification of tea grades was conducted in recent years, including green tea (such as Xihu Longjing tea [23] and Huangshan Maofeng tea [24]), oolong tea (such as Anxi Tiehuanyin tea [25], Wuyi Rougui Tea [26], and Yashi Xiang tea [27]), and even Sri Lankan tea products [28]. Additionally, related quality identification was also revealed based on standard tea samples.…”
Innovative Tangyang Congou black tea, also known as Minkehong black tea (MKH), is of high quality and hence has gained a reputation on the market. In this study, standard samples of MKH were used as the research material, and the results of sensory evaluation showed that the overall quality of MKH decreased along with the downgrading. The radar chart showed a strong association between higher grades and specific aroma and taste character. Based on the detection of ultra-performance liquid chromatography–mass spectrometry (UPLC–MS) and related analysis, the content of both the ester-type catechins and non-ester catechins decreased along with the downgrading, and the details of their change trends were revealed. The content and dynamic changes in caffeine were also investigated. A total of 19 kinds of amino acids (AAs) were clustered; among them, 4 kinds of AAs, namely, Thr, Leu, Asp, and Ile, significantly contributed to the taste of the tea. Notably, the content of Thr had the highest correlation with the grade of MKH, and the correlation coefficient was 0.991 (p < 0.01). According to gas chromatography–mass spectrometry (GC–MS) detection and analysis, a total of 861 kinds of volatile compounds were detected, the aroma-active compounds in different grades were selected, and an aroma wheel of MKH was constructed. Our results found that non-volatile and volatile compounds not only contribute to defining the level of MKH standard samples but also provide a chemical basis for the measurement of flavour and quality of MKH.
“…Wuyi rock tea is a typical oolong tea, and is semi-fermented and its production process is more complex than other types of tea ( Wong et al, 2022 ; Ye et al, 2023 ). High-quality Wuyi rock tea should have distinct characteristics such as fruity, floral, woody and fatty, and the key to the production of these odor characteristics lied in the preliminary processing ( Pang et al, 2022 ; Xu et al, 2022 ). The preliminary processing of Wuyi rock tea was mainly divided into two stages.…”
Fermentation is extremely important for the formation of the special flavor of Wuyi rock tea. This study determined volatile metabolite contents using GC-MS technique and futher analyzed their odor characteristics during the traditional deep fermentation technology of Wuyi rock tea. The results showed that 17 characteristic compounds significantly changed during the first stage of the preliminary processing, namely fresh leaves, withering and fermentation. The key to the formation of floral aroma lied in dihydromyrcenol, and the woody aroma derived from six terpenoids, and their synthesis depended on dihydromyrcenol content. The fruity aroma was dominated by six esters, and the fruity aroma mainly came from (Z) -3-hexen-1-yl butyrate, (E) -3-hexen-1-yl butyrate and 5-Hexenyl butyrate. This study provided an important theoretical and practical basis for improving the preliminary processing of Wuyi rock tea.
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