An Improved Method of Theabrownins Extraction and Detection in Six Major Types of Tea (<i>Camellia sinensis</i>)

Lee, Tzan-Chain; Zang, Qian-Nan; Lin, Kuan-Hung; Hu, Hua-Lian; Lu, Ping-Yuan; Zhang, Jing-Yao; Kang, Chun-Qin; Li, Yan-Jie; Ko, Tzu-Hsing

doi:https://doi.org/10.1155/2022/8581515

Journal of Chemistry

On this page

Abstract Introduction Materials and Methods Results and Discussion Conclusion Abbreviations Data Availability Conflicts of Interest Authors’ Contributions Acknowledgments Supplementary Materials References Copyright Related Articles

Special Issue

Natural Bioactive Compounds: Chemistry, Extraction, and Applications

View this Special Issue

Research Article | Open Access

Volume 2022 | Article ID 8581515 | https://doi.org/10.1155/2022/8581515

An Improved Method of Theabrownins Extraction and Detection in Six Major Types of Tea (Camellia sinensis)

Tzan-Chain Lee,^1,2Qian-Nan Zang,¹Kuan-Hung Lin,³Hua-Lian Hu,¹Ping-Yuan Lu,¹Jing-Yao Zhang,¹Chun-Qin Kang,¹Yan-Jie Li,⁴and Tzu-Hsing Ko⁵

Academic Editor: Marwa Fayed

Received13 Jul 2022

Revised17 Aug 2022

Accepted20 Aug 2022

Published27 Sept 2022

Abstract

Tea pigments consisting of theabrownins (TBs), theaflavins (TFs), and thearubigins (TRs) affect the color and taste of tea. TBs include a variety of water-soluble compounds, but do not dissolve in n-butanol and ethyl acetate. Previously, the traditional method of TB extraction only mixed tea with n-butanol, and TBs were retained in the water phase. However, without ethyl acetate extraction, TFs and TRs remained in the water phase and affected the detection of TB content. Although an improved method had been devised by adding an ethyl acetate extraction step between tea production and n-butanol extraction, the proportional equation for calculating TB content (%) was not yet developed. In this study, we compared the absorbance at 380 nm (A₃₈₀) of TB solutions from six major types of tea (green, yellow, oolong, white, black, and dark teas) extracted by improved and traditional methods from the same tea samples. Significantly lower A₃₈₀ values were obtained from TB solutions via the improved method compared to the traditional method for six major types of tea, and the highest and lowest slops in TB concentrations from A₃₈₀ analyses were from dark tea and green tea, respectively. Moreover, newly developed equations for TB content in those six tea types extracted by the improved methods were also established.

1. Introduction

Tea is either prepared by infusion or decoction of Camellia sinensis dried leaves, which are classified into six major types (green, oolong (or cyan), black, white, yellow, and dark) based on the manufacturing process. Both black and oolong teas are two kinds of aerated tea leaves. After plucking, these fresh leaves are processed by withering, rolling, aeration, and then inactivation by drying (Figure 1(a)). During the aeration process, polyphenols are oxidized by endogenous enzymes such as polyphenol oxidase and peroxidase, thus producing many oxidative compounds. Polyphenol oxidation results in the pigment’s dynamic transition into tea pigments that include TFs, TRs, and TBs [1, 2]. The relationship among TFs, TRs, and TBs is shown in Supplementary Figure 1. The transition induces color changes in tea leaves ranging from green to red brown [3]. All the pigments affect the color and flavor of liquid tea [3–7]. TBs give tea leaves a brown color and can be formed by TFs or TRs oxidation or polyphenol aggregation with other sugars and acidic compounds [8, 9]. The leaves of oolong tea are green with red edges (Figure 1(b)III) due to the formation and accumulation of oxidized polyphenols from leaf margins during the aeration process. As the aeration period proceeds, the surfaces of all tea leaves become reddish brown (Figure 1(b)I) and black tea leaves are produced. Therefore, oolong tea is “semioxidized” tea, and black tea is “fully oxidized” tea [10]. White tea is obtained by only withering and drying, as more prolonged withering leads to a severe water deficiency that induces membrane disintegration and polyphenol oxidization by endogenous enzymes. In addition, white tea can be stored for a long time, during which chemical reactions such as catechin and amino acid oxidation can occur that induce better flavor and taste (more sweetness and smoothness) and more health benefits [11–13].

(a)

(b)

The objective of our study was to “improve” (Figure 2) the abovementioned “traditional” method by adding an ethyl acetate extraction step between liquid tea production and n-butanol extraction. Moreover, our method’s new equations for the TB content (%) of the six major types of tea extraction had different absorbance values at 380 nm (A₃₈₀) and slope compared to black tea analyses by the traditional method.

2. Materials and Methods

2.1. Samples

The six major types of tea samples obtained are listed in Table 1. All were purchased from local tea markets located in Anxi, Fujian Province, Dali, Yunnan Province, and Chongqing City, China. Each tea sample was ground into tea powder using a grinder (Joyoung Co., Shandong, China) and then stored in sealed cans until analysis.

2.2. Preparation of Liquid Tea Samples

Boiling distilled and deionized water (d.d. H₂O; 125 mL) was added to 3.0 grams of tea powder in a 250 mL conical flask and shaken in a water bath at 90°C for 10 min. The liquid tea was then centrifuged at 1,800 × for 10 min at 4°C. The supernatant was diluted to 125 mL with d.d. H₂O and then divided into two aliquots, one for TB extraction by the traditional method and the other by our improved method (Figure 2).

2.3. TB Extraction

The traditional method was based on Yao et al. [33] and Roberts and Smith [35, 36], with a few modifications. Briefly, 25 mL of tea solution was extracted with the same volume of n-butanol (Xilong Scientific Co., Guangdong, China) and shaken for 3 min. The lower layer of the solution was then centrifuged at 1,800 × for 10 min at 4°C. Two mL of the supernatant was then mixed with 2 mL of saturated (10.2%) oxalic acid (SINOPHARM Co., Shanghai, China) and 6 mL of d.d. H₂O was then added, followed by dilution to 25 mL with 95% (v/v) ethanol (SINOPHARM Co., Shanghai, China). A₃₈₀ values of the above solutions were measured using a UV-1750 spectrophotometer (Shimadzu, Japan), and 95% (v/v) ethanol was used as a blank. TB content (%) = [7.06 × 2 × A₃₈₀ × 100%]/ [ × 1/3 × (1-M)] = [21.18 × 2 × A₃₈₀ × 100%]/ × (1-M), where “” is the weight (gram) of the tea sample, “M” is the moisture content (%) of the tea sample, and 21.18 is the inverse slope of A_380.

The improved method with TB concentrations from TB extracted samples was modified from the abovementioned traditional method. Mainly, 35 mL of ethyl acetate (SINOPHARM Co., Shanghai, China) was added to samples of the six tea types (35 mL) in a 125 mL separating funnel and shaken for 3 min. After discarding the upper layer, the lower layer (25 mL) was then extracted with 25 mL of n-butanol (Xilong Scientific Co., Guangdong, China) and shaken for 3 min; the lower layer solution was used for centrifugation at 1,800 × for 10 min at 4°C. The A₃₈₀ detections of the solutions were done the same way as in the abovementioned traditional method, and TB contents (%) were determined by the six equations for the improved method. TB in the six tea types was extracted by the improved method and then freeze-dried. Freeze-dried samples were dissolved in d.d. H₂O, various concentrations of TB solution (2 mL) were mixed with 2 mL of saturated oxalic acid, 6 mL of d.d. H₂O was added, and the samples were then diluted to 25 mL with 95% (v/v) ethanol. Samples were then measured at A₃₈₀.

2.4. Moisture

Moisture in the tea powder was measured using a vacuum oven according to an international standard method (ISO1573 (BS6049-2), 1980).

2.5. Data Analysis

Paired data with A₃₈₀ values of both traditional and improved methods were subjected to paired t-tests using Microsoft Excel 2019. TB contents (%) are presented as mean values ± standard deviations (SD) of twelve independent sets of experiments with similar results. Paired t-tests were calculated with high significance at using SPSS version 23.0 (SPSS, Chicago, USA). Linear equations were established by regression analysis between A₃₈₀ measurements and TB concentrations of the six tea types using SigmaPlot ver. 12.5 (SYSTAT Software, San Jose, CA).

3. Results and Discussion

3.1. Comparisons of TB Extractions between Traditional and Improved Methods

Figure 3 illustrates A₃₈₀ values from TB solutions extracted by traditional and improved methods. Readings from the improved method were significantly lower (around 80–90%) compared to the traditional method in all six tea types, indicating that ethyl acetate extraction removes TFs and portions of TRs from liquid tea [33] and decreases TB A₃₈₀ values. TB compositions were different between these extraction methods, and revised parameters for the improved method should therefore be established.

After plucking, yellow, green, and dark tea leaves are first fixed by steaming or pan-frying (Figure 1(a)) to inactivate all endogenous enzymes. Green tea is produced after rolling and drying. Yellow tea is obtained when tea leaves are kept wet and under high temperatures for 6 to 12 h (Figure 1(a)) between fixing and drying, during which chlorophylls are degraded and polyphenols are auto-oxidized. Dark tea is harvested after leaves have been kept wet and microorganisms grow on their surfaces for many days between fixing and drying (Figure 1(a)). During this piling process, microbes (mainly Aspergillus fumigatus, Aspergillus Niger, and Saccharomyces cerevisiae) secrete many enzymes to induce polyphenol oxidation, cell wall degradation, and fermentation [14–17]. TB content increases during dark tea processing [18], and the leaves become dark brown (Figure 1(b)).

Similar plant secondary metabolites can reduce the risk of age-related chronic diseases and promote health benefits [19, 20]. TBs have physiological functions such as reducing blood lipid and blood sugar levels [21–23]; controlling of diabetes mellitus [24]; attenuation of hypercholesterolemia [25, 26]; reducing serum levels of total cholesterol, low-density cholesterol, and triglycerides [27]; and osteoclastogenesis suppression and prevention of bone loss [28], together with inhibition of cell cycling and tumor cell growth [29]. In addition, TB content is a positive parameter in evaluating fragrance and flavor in dark tea and white tea [9, 18, 30, 31]. Zhu et al. [32] and Cheng et al. [18] reported that stringent taste levels were decreased and stale and fungal aromas increased with TB content. Furthermore, dark tea and white tea leaves can be stored for a long time, and longer storage times result in higher TB content [14]. In contrast, during storage, an increased TB content worsens tea quality in both black tea and oolong tea due to the loss of aroma and sweetness molecules [5, 7, 33]. Therefore, TB content may be an objective measure of tea quality [34]. Yao et al. [33] combined three methods [35–37] to analyze TF, TR, and TB contents and constructed a “traditional” method of TB extraction (Figure 2). However, TBs are defined as a variety of water-soluble compounds but are not dissolved in n-butanol and ethyl acetate [22, 27]. In the traditional method, without ethyl acetate extraction, TFs or TRs would be retained in the TB layer solution and thus affect the accuracy of TB content analysis, because A₃₈₀ is detected from TF, TR, and TB solutions. In addition, the TB equation was based on black tea samples extracted from the traditional method [33, 35, 36]. Whether the slop parameter of the black tea equation is the same as other types of tea remains unknown.

(a)

(b)

(c)

(d)

(e)

(f)

Figure 3

Comparisons of A₃₈₀ values with TB extractions by the traditional method (black bar) and the improved method (white bar) of six major types of tea: green tea (a), yellow tea (b), oolong tea (c), white tea (d), black tea (e), and dark tea (f). Test numbers of tea samples (1∼11) in each major type of tea: (a) 1–5, Longjing, and 6–11, Jinyun Maofeng in green tea. (b) 1–11, Huoshan Huangya in yellow tea. (c) 1–4, Anxi Tieguanyin, and 5–11, Wuyi Dahongpao in oolong tea. (d) 1–6, four-years-old Baimudan, and 7–11, four-years-old Gong-Mei white tea. (e) 1–6, Yunnan black tea, and 7–11, Lapsang Souchong black tea. (f) 1–6, four-years-old, ripened Pu-Erh teas, and 7–11, four-years-old, ripened Pu-Erh caked dark tea.

3.2. Equations Established for the Improved Method

The traditional method’s empirical equation for determining TB content (%) is [21.18 × 2 × A₃₈₀ × 100%]/ (1-M), where “” stands for the weight (in grams) of tea sample powder and 21.18 is the inverse slope of A₃₈₀ based on black tea [33, 35, 36]. In our study, six major types of tea were extracted by the improved method, their solutions were freeze-dried, and TB powder was collected. After TB powders were dissolved in d.d. H₂O, different A₃₈₀ values were observed from the samples. Figure 4 shows that A₃₈₀ values were significantly () and positively correlated with the TB concentrations of green tea (r = 0.9963, R² = 0.9926), yellow tea (r = 0.9961, R² = 0.9922), oolong tea (r = 0.9977, R² = 0.9954), black tea (r = 0.9987, R² = 0.9975), white tea (r = 0.9973, R² = 0.9947), and dark tea (r = 0.9975, R² = 0.9950). Regression equation slopes for dark tea, white tea, black tea, oolong tea, yellow tea, and green tea were 0.0704, 0.0475, 0.0381, 0.0350, 0.0166, and 0.0160, respectively. Furthermore, the inverse slopes of dark tea, white tea, black tea, oolong tea, yellow tea, and green tea were 14.205, 21.053, 26.247, 28.571, 60.241, and 62.5, respectively. The equations for the six tea types using the improved method were as follows: dark tea: [14.205 × 2 × A₃₈₀ × 100%]/ × (1-M), white tea: [21.053 × A₃₈₀ × 100%]/ × (1-M), black tea: [26.247 × 2 × A₃₈₀ × 100%]/ × (1-M), oolong tea: [28.571 × 2 × A₃₈₀ × 100%]/ × (1-M), yellow tea: [60.241 × 2 × A₃₈₀ × 100%]/ × (1-M), and green tea: [62.5 × 2 × A₃₈₀ × 100%]/ × (1-M).

In those empirical equations, “M” means the tea sample’s moisture content (%) and “w” stands for the weight (in grams) of tea sample powder. Figure 4 shows that two types of aerated tea (black tea and oolong tea) had similar variations, but green tea and yellow tea almost completely overlapped, indicating that the TB compositions were similar in these two types of tea. Wang et al. [38] demonstrated that green tea and yellow tea had similar chemical components according to metabolome analysis. After high-temperature treatments in fixation and drying processes during storage, isomer flavanols and chlorophyll metabolites (e.g., pheophytins) were produced in the autooxidation process, and the color of tea leaves turned olive brown [39–43]. The slope of white tea was higher than that of black tea and lower than that of dark tea (Figure 4), implying that the TB composition in white tea is notably different from that in dark tea and black tea. Although liquid chromatography-mass spectrometry analysis was used to determine the chemical composition in white tea after long-term storage [11, 12, 44], the TB composition still remained unknown. In addition, the TB of dark tea contains some fungi-specific metabolites detected by gas chromatography-mass spectrometry or liquid chromatography-mass spectrometry-based metabolomics [18, 23, 32, 45–49].

3.3. Comparison of TB Content between Traditional and Improved Methods in Tea Extractions

TBs were extracted by both traditional and improved methods, and calculations were made with appropriate equations at A₃₈₀. Figure 5 shows that the TB contents of these two methods were significantly different () in all types of liquid teas.

We repeated many studies by using the traditional extraction method and found that dark tea had the highest TB content (10%∼14%) of the six tea types [14, 15, 50, 51], followed by black tea (7%∼9%) [14, 50, 52], and ranges of 2%∼3.5% in green tea and yellow tea [50, 52]. The improved method showed that black tea had the highest TB content (7.97%∼11.19%, average 9.75%), and oolong tea ranged 2.65%∼6.23% with an average of 5.25%. Black tea and oolong tea were oxidized by endogenous enzymes in a longer aeration process and had higher TB contents. The TB contents of white tea ranged from 5.35% to 8.02%, averaging 7.03%, suggesting that four years of storage was sufficient to transfer high levels of TB content in the leaves. The TB contents of dark tea ranged from 5.66 to 7.66%, averaging 6.96%, while green tea and yellow tea ranged from 2.63 to 4.46% with an average of 4.03% and 3.87 to 5.2% with an average of 4.61%, respectively, indicating that their values differed significantly from levels derived from the traditional extraction method. Dark tea had the highest A₃₈₀ of the six tea types (Figure 3); however, high slop in TB concentrations (Figure 4) resulted in TB content not being as high as with the traditional method (Figure 5). TB composition is formed during tea processing, and the aeration procedure is one of the most important steps in black tea and oolong tea processing, while it does not occur in other teas. Therefore, different equations are proposed to calculate TB content in different types of tea, especially dark tea, yellow tea, and green tea.

4. Conclusion

This study provided an improved method for the analysis of TB content (%) from six major types of tea. This method decreases the A₃₈₀ values of TBs with differing TB absorbance capabilities in six major types of tea. Six equations have been developed to analyze TB content (%) in those six tea types extracted by an improved method, and the ranges of TB content (%) showed significant differences compared to the traditional method.

Abbreviations

SD:	Standard deviation

Data Availability

The data used to support this study are available from the corresponding author upon request.

Conflicts of Interest

The authors declare that there are no conflicts of interest regarding the publication of this article.

Authors’ Contributions

T-C L. designed the experiments; T-C L. and Q-N Z. collected the sample, conducted experiments, and analyzed the data. T-C L. and K-H L. wrote the article; T-C L., Q-N Z., H-L H., P-Y L., J-Y Z., C- K., and Y-J L. collected the sample and investigated the study; T-H Ko projected-ministration and reviewed and edited the manuscript.

Acknowledgments

This work was supported by the Starting Research Fund from the Fujian Agriculture and Forestry University (KXR19001), and the Starting Research Fund from the Wuzhou University (WZUQDJJ30173).

Supplementary Materials

Supplementary Figure 1: the simplified scheme of relationship among TF, TR, and TB. (Supplementary Materials)

References

E. Haslam, “Thoughts on thearubigins,” Phytochemistry, vol. 64, pp. 61–73, 2003.
View at: Google Scholar
G. S. Gill, A. Kumar, and R. Agarwal, “Monitoring and grading of tea by computer vision–a review,” Journal of Food Engineering, vol. 106, pp. 13–19, 2011.
View at: Google Scholar
C. Dong, G. Liang, B. Hu et al., “Prediction of congou black tea fermentation quality indices from color features using non-linear regression methods,” Scientific Reports, vol. 8, Article ID 10535, 2018.
View at: Google Scholar
M. Obanda, P. Okinda O, and R. Mang’Oka, “Changes in the chemical and sensory quality parameters of black tea due to variations of fermentation time and temperature,” Food Chemistry, vol. 75, no. 4, pp. 395–404, 2001.
View at: Publisher Site | Google Scholar
M. Obanda, P. O. Owuor, R. Mang’oka, and M. M. Kavoi, “Changes in thearubigin fractions and theaflavin levels due to variations in processing conditions and their influence on black tea liquor brightness and total colour,” Food Chemistry, vol. 85, no. 2, pp. 163–173, 2004.
View at: Publisher Site | Google Scholar
M. Cavia-Saiz, M. D. Busto, M. C. Pilar-Izquierdo, N. Ortega, M. Perez-Mateos, and P. Muñiz, “Antioxidant properties, radical scavenging activity and biomolecule protection capacity of flavonoid naringenin and its glycoside naringin, a comparative study,” Journal of the Science of Food and Agriculture, vol. 90, no. 7, pp. 1238–1244, 2010.
View at: Publisher Site | Google Scholar
K. Wang, Q. Chen, Y. Lin, and Z. Liu, “Comparison of phenolic compounds and taste of Chinese black tea,” Food Science and Technology Research, vol. 20, no. 3, pp. 639–646, 2014.
View at: Publisher Site | Google Scholar
J. T. Dwyer and J. Peterson, “Tea and flavonoids: where we are, where to go next,” The American Journal of Clinical Nutrition, vol. 98, no. 6, pp. 1611S–1618S, 2013.
View at: Publisher Site | Google Scholar
Q. P. Wang, J. S. Gong, Y. Chisti, and S. Sirisansaneeyakul, “Production of theabrownins using a crude fungal enzyme concentrate,” Journal of Biotechnology, vol. 231, pp. 250–259, 2016.
View at: Publisher Site | Google Scholar
Q. Zhang, J. Ruan, B. Caballero, P. M. Finglas, and F. Toldrá, “Tea: analysis and tasting,” Encyclopedia of Food and Health, Academic Press, Oxford, U K, 2016.
View at: Google Scholar
J. M. Ning, D. Ding, Y. S. Song, Z. Z. Zhang, X. Luo, and X. C. Wang, “Chemical constituents analysis of white tea of different qualities and different storage times,” European Food Research and Technology, vol. 242, pp. 2093–2104, 2016.
View at: Google Scholar
D. Qi, A. Miao, J. Cao et al., “Study on the effects of rapid aging technology on the aroma quality of white tea using GC-MS combined with chemometrics: in comparison with natural aged and fresh white tea,” Food Chemistry, vol. 265, pp. 189–199, 2018.
View at: Publisher Site | Google Scholar
F. Y. Fan, C. S. Huang, Y. L. Tong et al., “Widely targeted metabolomics analysis of white peony teas with different storage time and association with sensory attributes,” Food Chemistry, vol. 362, Article ID 130257, 2021.
View at: Publisher Site | Google Scholar
Q. Wang, C. Peng, and J. Gong, “Effects of enzymatic action on the formation of theabrownin during solid state fermentation of Pu-erh tea,” Journal of the Science of Food and Agriculture, vol. 91, no. 13, pp. 2412–2418, 2011.
View at: Publisher Site | Google Scholar
W. N. Wang, L. Zhang, S. Wang et al., “8-C N-ethyl-2-pyrrolidinone substituted flavan-3-ols as the marker compounds of Chinese dark teas formed in the post-fermentation process provide significant antioxidative activity,” Food Chemistry, vol. 152, pp. 539–545, 2014.
View at: Publisher Site | Google Scholar
D. Haas, B. Pfeifer, C. Reiterich, R. Partenheimer, B. Reck, and W. Buzina, “Identification and quantification of fungi and mycotoxins from Pu-erh tea,” International Journal of Food Microbiology, vol. 166, no. 2, pp. 316–322, 2013.
View at: Publisher Site | Google Scholar
Z. J. Zhao, H. R. Tong, L. Zhou, E. X. Wang, and Q. J. Liu, “Fungal colonization of Pu-erh tea in Yunnan,” Journal of Food Safety, vol. 30, no. 4, pp. 769–784, 2010.
View at: Publisher Site | Google Scholar
L. Cheng, Q. Yang, Z. Chen et al., “Distinct changes of metabolic profile and sensory quality during qingzhuan tea processing revealed by LC-MS-based metabolomics,” Journal of Agricultural and Food Chemistry, vol. 68, no. 17, pp. 4955–4965, 2020.
View at: Publisher Site | Google Scholar
I. Shah, M. A. Shah, M. A. Nawaz et al., “Analysis of other phenolics (capsaicin, gingerol and alkylresorcinols),” Recent Advances in Natural Products Analysis, Elsevier, Amsterdam, Netherland, 2020.
View at: Google Scholar
M. Bule, I. A. Issa, F. Khan et al., “Development of new food products based on phytonutrients,” Phytonutrients in Food from Traditional to Rational Usage, Woodhead Publishing, Cambridge, UK, 2020.
View at: Google Scholar
R. A. Anderson and M. M. Polansky, “Tea enhances insulin activity,” Journal of Agricultural and Food Chemistry, vol. 50, no. 24, pp. 7182–7186, 2002.
View at: Publisher Site | Google Scholar
J. S. Gong, C. X. Peng, T. Chen, B. Gao, and H. J. Zhou, “Effects of theabrownin from Pu-erh tea on the metabolism of serum lipids in rats: mechanism of action,” Journal of Food Science, vol. 75, no. 6, pp. H182–H189, 2010.
View at: Publisher Site | Google Scholar
Y. Xiao, M. Li, Y. Wu, K. Zhong, and H. Gao, “Structural characteristics and hypolipidemic activity of theabrownins from dark tea fermented by single species Eurotium cristatum PW-1,” Biomolecules, vol. 10, no. 2, 2020, Pub. ID. 204.
View at: Publisher Site | Google Scholar
S. Culas, R. A. U. J. Marapana, I. R. Palangasinghe, and A. C. Liyanage, “Development of liquid-based tea and its antidiabetic effect,” Journal of Chemistry, vol. 2021, Article ID 8863936, 6 pages, 2021.
View at: Publisher Site | Google Scholar
Y. Hou, W. F. Shao, R. Xiao et al., “Pu-erh tea aqueous extracts lower atherosclerotic risk factors in a rat hyperlipidemia model,” Experimental Gerontology, vol. 44, no. 6-7, pp. 434–439, 2009.
View at: Publisher Site | Google Scholar
F. Huang, X. Zheng, X. Ma et al., “Theabrownin from Pu-erh tea attenuates hypercholesterolemia via modulation of gut microbiota and bile acid metabolism,” Nature Communications, vol. 10, no. 1, 2019, Pub. ID. 4971.
View at: Publisher Site | Google Scholar
C. X. Peng, Q. P. Wang, H. R. Liu, B. Gao, J. Sheng, and J. S. Gong, “Effects of Zijuan pu-erh tea theabrownin on metabolites in hyperlipidemic rat feces by Py-GC/MS,” Journal of Analytical and Applied Pyrolysis, vol. 104, pp. 226–233, 2013.
View at: Publisher Site | Google Scholar
T. Liu, Z. Xiang, F. Chen et al., “Theabrownin suppresses in vitro osteoclastogenesis and prevents bone loss in ovariectomized rats,” Biomedicine & Pharmacotherapy, vol. 106, pp. 1339–1347, 2018.
View at: Publisher Site | Google Scholar
L. Zhou, F. Wu, W. Jin et al., “Theabrownin inhibits cell cycle progression and tumor growth of lung carcinoma through c-myc-related mechanism,” Frontiers in Pharmacology, vol. 8, 2017, Pub. ID. 75.
View at: Publisher Site | Google Scholar
P. O. Owuor and M. Obanda, “The use of green tea (Camellia sinensis) leaf flavan-3-ol composition in predicting plain black tea quality potential,” Food Chemistry, vol. 100, no. 3, pp. 873–884, 2007.
View at: Publisher Site | Google Scholar
P. Tang, D.-Y. Shen, Y.-Q. Xu, X.-C. Zhang, J. Shi, and J.-F. Yin, “Effect of fermentation conditions and plucking standards of tea leaves on the chemical components and sensory quality of fermented juice,” Journal of Chemistry, vol. 2018, Article ID 4312875, 7 pages, 2018.
View at: Publisher Site | Google Scholar
M. Z. Zhu, N. Li, F. Zhou et al., “Microbial bioconversion of the chemical components in dark tea,” Food Chemistry, vol. 312, Article ID 126043, 2020.
View at: Publisher Site | Google Scholar
L. H. Yao, Y. Jiang, N. Caffin et al., “Phenolic compounds in tea from Australian supermarkets,” Food Chemistry, vol. 96, no. 4, pp. 614–620, 2006.
View at: Publisher Site | Google Scholar
Z. Feng, Y. Li, M. Li et al., “Tea aroma formation from six model manufacturing processes,” Food Chemistry, vol. 285, pp. 347–354, 2019.
View at: Publisher Site | Google Scholar
E. A. H. Roberts and R. F. Smith, “Spectrophotometric measurements of theaflavins and thearubigins in black tea liquors in assessments of quality in teas,” Analyst, vol. 86, no. 1019, pp. 94–98, 1961.
View at: Publisher Site | Google Scholar
E. A. H. Roberts and R. F. Smith, “The phenolic substances of manufactured tea. IX. –The spectrophotometric evaluation of tea liquors,” Journal of the Science of Food and Agriculture, vol. 14, no. 10, pp. 689–700, 1963.
View at: Publisher Site | Google Scholar
L. H. Yao, Y. Chen, and C. Cheng, “The kinetics of black tea infusion,” Journal of Food and Fermentation and Industry, vol. 19, pp. 38–44, 1993.
View at: Google Scholar
Y. Wang, Z. Kan, H. J. Thompson et al., “Impact of six typical processing methods on the chemical composition of tea leaves using a single Camellia sinensis cultivar, Longjing 43,” Journal of Agricultural and Food Chemistry, vol. 67, no. 19, pp. 5423–5436, 2019.
View at: Publisher Site | Google Scholar
J. L. Lu, S. S. Pan, X. Q. Zheng, J. J. Dong, D. Borthakur, and Y. R. Liang, “Effects of lipophillic pigments on colour of the green tea infusion,” International Journal of Food Science and Technology, vol. 44, no. 12, pp. 2505–2511, 2009.
View at: Publisher Site | Google Scholar
V. Sai, P. Chaturvedula, and I. Prakash, “The aroma, taste, color and bioactive constituents of tea,” Journal of Medicinal Plants Research, vol. 5, pp. 2110–2124, 2011.
View at: Google Scholar
L. Kusmita, I. Puspitaningrum, and L. Limantara, “Identification, isolation and antioxidant activity of pheophytin from green tea (Camellia sinensis, (L.) Kuntze),” Procedia Chemistry, vol. 14, pp. 232–238, 2015.
View at: Publisher Site | Google Scholar
X. Li, R. Zhou, K. Xu et al., “Rapid determination of chlorophyll and pheophytin in green tea using fourier transform infrared spectroscopy,” Molecules, vol. 23, no. 5, 2018, Pub. ID. 1010.
View at: Publisher Site | Google Scholar
X. Yu, S. Hu, C. He et al., “Chlorophyll metabolism in postharvest tea (Camellia sinensis L.) leaves: variations in color values, chlorophyll derivatives, and gene expression levels under different withering treatments,” Journal of Agricultural and Food Chemistry, vol. 67, no. 38, pp. 10624–10636, 2019.
View at: Publisher Site | Google Scholar
D. Xie, W. Dai, M. Lu et al., “Nontargeted metabolomics predicts the storage duration of white teas with 8-C N-ethyl-2-pyrrolidinone-substituted flavan-3-ols as marker compounds,” Food Research International, vol. 125, Article ID 108635, 2019.
View at: Publisher Site | Google Scholar
L. Zhang, W.-W. Deng, and X.-C. Wan, “Advantage of LC-MS metabolomics to identify marker compounds in two types of Chinese dark tea after different post-fermentation processes,” Food Science and Biotechnology, vol. 23, no. 2, pp. 355–360, 2014.
View at: Publisher Site | Google Scholar
P. Long, M. Wen, D. Granato et al., “Untargeted and targeted metabolomics reveal the chemical characteristic of pu-erh tea (Camellia assamica) during pile-fermentation,” Food Chemistry, vol. 311, 2020, Pub. ID. 125895.
View at: Publisher Site | Google Scholar
Y. Ma, T.-J. Ling, X.-Q. Su et al., “Integrated proteomics and metabolomics analysis of tea leaves fermented by Aspergillus niger, Aspergillus tamarii and Aspergillus fumigatus,” Food Chemistry, vol. 334, Article ID 127560, 2021.
View at: Publisher Site | Google Scholar
J. Shi, W. Ma, C. Wang et al., “Impact of various microbial-fermented methods on the chemical profile of dark tea using a single raw tea material,” Journal of Agricultural and Food Chemistry, vol. 69, no. 14, pp. 4210–4222, 2021.
View at: Publisher Site | Google Scholar
W. Zhang, J. Cao, Z. Li et al., “HS-SPME and GC/MS volatile component analysis of Yinghong No. 9 dark tea during the pile fermentation process,” Food Chemistry, vol. 357, Article ID 129654, 2021.
View at: Publisher Site | Google Scholar
G. Xie, M. Ye, Y. Wang et al., “Characterization of pu-erh tea using chemical and metabolic profiling approaches,” Journal of Agricultural and Food Chemistry, vol. 57, no. 8, pp. 3046–3054, 2009.
View at: Publisher Site | Google Scholar
C. Tan, J. S. Gong, and L. P. Bao, “Study on theabrownin physicochemical and microbial change in the fermentation process of Zijuan green tea,” Food and Fermentation Industries, vol. 12, pp. 43–48, 2011.
View at: Google Scholar
C. X. Peng, J. Liu, H. R. Liu, H. J. Zhou, and J. S. Gong, “Influence of different fermentation raw materials on pyrolyzates of Pu-erh tea theabrownin by Curie-point pyrolysis-gas chromatography–mass spectroscopy,” International Journal of Biological Macromolecules, vol. 54, pp. 197–203, 2013.
View at: Publisher Site | Google Scholar
W. Tao, Z. Zhou, B. Zhao, and T. Wei, “Simultaneous determination of eight catechins and four theaflavins in green, black and oolong tea using new HPLC–MS–MS methodflavins ingreen, black and oolong tea using new HPLC–MS–MS method,” Journal of Pharmaceutical and Biomedical Analysis, vol. 131, pp. 140–145, 2016.
View at: Publisher Site | Google Scholar

Copyright

Copyright © 2022 Tzan-Chain Lee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

PDF Download Citation

Download other formats

Order printed copies

Views

600

Downloads

539

Citations