Investigation of Processes in Black Tea Manufacture through Model Fermentation (Oxidation) Experiments

Stodt, Ulf W.; Blauth, Nadine; Niemann, Steffi; Stark, Janina; Pawar, Vikas; Jayaraman, Sujatha; Koek, J. H.; Engelhardt, Ulrich H.

doi:10.1021/jf501591j

Cited by 96 publications

(64 citation statements)

References 25 publications

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“…From the microbiological view, the post-fermentation of PFPT is a solid-state fermentation (SSF). Unlike the chemical changes of black tea in fermentation, which are catalyzed by endogenous enzymes in tea leaves [3,4], the chemical changes in the SSF of PFPT are catalyzed by the microbial enzymes [1]. Presently, the SSF of PFPT is a natural fermentation without the use of starter cultures or the sterilization of raw materials.…”

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confidence: 99%

Microbial Succession and the Dynamics of Chemical Compounds during the Solid-State Fermentation of Pu-erh Tea

Duan

Zhang

et al. 2017

Applied Sciences

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An in-depth knowledge of the microbiota and metabolites in the solid-state fermentation (SSF) of Post-fermented Pu-erh tea (Pu-erh Shucha, PFPT), a Chinese traditional tea with various health benefits, is essential to develop modern fermentation technology. In this work, the microbial diversity and succession in two laboratory-developed SSF protocols for PFPT were investigated using pyrosequencing analyses of the bacterial 16S rRNA and fungal 18S rRNA genes. The active bacteria in the initial stages of SSF (seven days) were from the raw materials and environment, with a dominance of Proteobacteria in both the raw materials and SSF after seven days. The environmental bacteria were inoculated into the tea mass throughout the fermentation process and multiplied, with a dominance of Firmicutes at day 14 and 21, and then Firmicutes and Actinobacteria at the last stages of fermentation (day 28 and 35). The dominant fungi came from the raw material and were identified at the genus level as Aspergillus throughout the SSF process. The contents of tea polyphenols, free amino acids, gallic acid, theaflavin, thearubigin, and catechins decreased significantly (p < 0.05), while the level of theabrownin increased significantly (p < 0.05). The caffeine content showed no significant change (p > 0.05). In total, 30 bacterial and three fungal genera showed significant correlations to 1-8 and 3-4 identified tea compounds, respectively (p < 0.05). The dynamics of the microbiota and chemical compounds, and correlations between their changes in the SSF of PFPT were revealed, and present a foundation for further studies on the microbial effects on chemical compounds.

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confidence: 99%

Microbial Succession and the Dynamics of Chemical Compounds during the Solid-State Fermentation of Pu-erh Tea

Duan

Zhang

et al. 2017

Applied Sciences

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“…Polyphenol oxidase and peroxidase are thought to play a role in the fermentation process, oxidation and formation of black tea compounds , Emdadi et al 2009, Stodt et al 2014. Also, they lead to the formation of black tea polyphenols and aroma compounds characteristic of black tea and involved in the plants' defence mechanism against environmental stresses [Harbowy and Balentine 1997].…”

Section: Resultsmentioning

confidence: 99%

The effect of bacteria-based formulations on tea (Camellia sinensis L.) growth, yield, and enzyme activities

Çakmakçı

Atasever

Erat

et al. 2017

Annals of Warsaw University of Life Sciences - SGGW - Horticulture and Landscape Architecture

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“…In general, CTC tea requires a shorter fermentation time, as it involves extensive cell rupturing, thereby leading to more exposed area for the enzymes and oxygen. As shown in Figure 2, the concentrations of TF and TR as well as the desirable quality characteristics increase with fermentation time, reaching optimum levels and then degrading if the fermentation time is prolonged (Sanyal, 2011;Stodt et al, 2014). If fermentation time is extended, TF gradually degrade to TR, and the body of tea liquor becomes thick (Borah and Bhuyan, 2003;Gill et al, 2011).…”

Section: Effect Of the Fermentation Process Parameters On The Qualitymentioning

confidence: 99%

“…TF are responsible for the brightness, briskness, and quality of tea liquor, and the color, taste, and body are determined by the content of TR. TF and TR are responsible for two main color pigments, orange-red and reddish-brown, respectively (Chen et al, 2010;Chen et al, 2012;Stodt et al, 2014).…”

Section: Sensory Characteristics Colormentioning

confidence: 99%

Fermentation: The Key Step in the Processing of Black Tea

Pou¹

2016

Journal of Biosystems Engineering

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Background: The same plant, Camellia sinensis, is used to produce all types of tea, and the differences among the various types arise from the different processing steps that are used. Based on the degree of fermentation, tea can be classified as black, green, white, or oolong tea. Of these, black tea is the most or fully fermented tea. The oxidized polyphenolic compounds such as theaflavins (TF) and thearubigins (TR) formed during fermentation are responsible for the color, taste, flavor, and aroma of black tea. Results: Research indicates that an optimum ratio of TF and TR (1:10) is required to ensure a quality cup of tea. The concentrations of TF and TR as well as desirable quality characteristics increase as fermentation time increases, reaching optimum levels and then degrading if the fermentation time is prolonged. It is also necessary to control the environment for oxidation. There are no established environment conditions that must be maintained during the fermentation of the ruptured tea leaves. However, in most cases, the process is performed at a temperature of 24-29°C for 2-4 h or 55-110 min for orthodox tea or crush, tear, and curl (CTC) black tea, respectively, under a high relative humidity of 95-98% with an adequate amount of oxygen. Conclusion: The polyphenolic compounds in black tea such as TF and TR as well as un-oxidized catechins are responsible for the health benefits of tea consumption. Tea is rich in natural antioxidant activities and is reported to have great potential for the management of various types of cancers, oral health problems, heart disease and stroke, and diabetes and to have other health benefits such as the ability to detoxify, improve urine and blood flow, stimulate, and improve the immune system.

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Investigation of Processes in Black Tea Manufacture through Model Fermentation (Oxidation) Experiments

Cited by 96 publications

References 25 publications

Microbial Succession and the Dynamics of Chemical Compounds during the Solid-State Fermentation of Pu-erh Tea

Microbial Succession and the Dynamics of Chemical Compounds during the Solid-State Fermentation of Pu-erh Tea

The effect of bacteria-based formulations on tea (Camellia sinensis L.) growth, yield, and enzyme activities

Fermentation: The Key Step in the Processing of Black Tea

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