Influence of catechins and theaflavins on the astringent taste of black tea brews

Zhang, Ding; Kuhr, Susanne; Engelhardt, Ulrich H.

doi:10.1007/bf01201768

Cited by 84 publications

(47 citation statements)

References 11 publications

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“…In terms of green leaf total polyphenol content BB35 was much lower than a number of other clones and was therefore expected to be ranked as low. This lack of precision in the prediction of quality by the phenol reagent method was evidence of the fact that the method determines all phenolic components present in the green leaf whereas the same components give rise to di †erent organoleptic responses in black tea (Sanderson et al 1976 ;Ding et al 1992). Not all Ñavanols are consumed in fermentation reactions during black tea processing (Ding et al 1992 ;Kuhr and Engelhardt 1992).…”

Section: Discussionmentioning

confidence: 97%

“…This lack of precision in the prediction of quality by the phenol reagent method was evidence of the fact that the method determines all phenolic components present in the green leaf whereas the same components give rise to di †erent organoleptic responses in black tea (Sanderson et al 1976 ;Ding et al 1992). Not all Ñavanols are consumed in fermentation reactions during black tea processing (Ding et al 1992 ;Kuhr and Engelhardt 1992). These residual unoxidised Ñavanols, which are colourless, contribute to the astringency of black tea (Sanderson et al 1976), and thus directly inÑuence the sensory evaluation of the black teas (Ding et al 1992).…”

Section: Discussionmentioning

confidence: 98%

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Flavanol Composition and Caffeine Content of Green Leaf as Quality Potential Indicators of Kenyan Black Teas

Obanda¹,

Owuor²,

Taylor

1997

J. Sci. Food Agric.

217

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The flavanol composition and caffeine content of green tea leaf, black tea quality parameters of theaflavins, thearubigins, liquor brightness and total colour varied more among clones than with time of the year. In green leaf, either (‐)epicatechin gallate or (‐)epigallocatechin gallate was the dominant flavanol present. Regression analysis of tasters' preferences for black teas against green leaf chemical components showed positive and significant correlations for (‐)epicatechin gallate (r = 0·498, P ⩽ 0·05 for taster A; r = 0·665, P ⩽ 0·01 for taster B, and r = 0·678, P ⩽ 0·01 for both tasters' overall ranking), (‐)epigallocatechin gallate (r = 0·513, P ⩽ 0·05 for taster B; r = 0·532, P ⩽ 0·05 for both tasters' overall ranking and caffeine (r = 0·523, P ⩽ 0·05 for taster A; r = 0·657, P ⩽ 0·01 for taster B; and r = 0·686, P ⩽ 0·01 for both tasters' overall ranking). Similar regressions against black tea theaflavins, thearubigin content, liquor brightness and total colour were not significant. The results suggest that the green leaf chemical components, (‐)epicatechin gallate, (‐)epigallocatechin gallate and caffeine could be used as quality potential indicators during clonal selection and propagation. © 1997 SCI.

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Section: Discussionmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 98%

Flavanol Composition and Caffeine Content of Green Leaf as Quality Potential Indicators of Kenyan Black Teas

Obanda¹,

Owuor²,

Taylor

1997

J. Sci. Food Agric.

217

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“…Of the four major TFs, the amount of theaflavin-3-3´-digallate (TF4) was the highest and simple theaflavin (TF1) was the lowest. Owuor et al (2006) reported the astringency level of TF4 to be 6.4 times and TF3 and TF2 2.2 times more than TF1.The level of astringency and/or briskness is usually associated with simple theaflavin, theaflavin-digalate equivalent and unoxidised catechins (Ding et al 1992). In our study it was observed that significant level of tasters' brightness, briskness, strength and quality was more in TF1 which was in conformity with earlier observations (Ding et al 1992).…”

Section: Resultsmentioning

confidence: 99%

Spatial variability of theaflavins and thearubigins fractions and their impact on black tea quality

et al. 2015

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The spatial distribution of theaflavin and thearubigin fractions and their impact on black tea quality were investigated using multivariate and geostatistics techniques. Black tea samples were collected from tea gardens of six geographical regions of Assam and West Bengal, India. Total theaflavin (TF) and its four fractions of upper Assam, south bank and North Bank teas were higher than the other regions. Simple theaflavin showed highest significant correlation with tasters' quality. Low molecular weight thearubigins of south bank and North Bank were significantly higher than other regions. Total thearubigin (TR) and its fractions revealed significant positive correlation with tasters' organoleptic valuations. Tea tasters' parameters were significantly and positively correlated with each other. The semivariogram for quality parameters were best represented by gaussian models. The nugget/sill ratio indicated a strong/ moderate spatial dependence of the studied parameters. Spatial variation of tea quality parameters may be used for quality assessment in the tea growing areas of India.

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“…EGCG is also a component of black tea, but the present method is not considered suitable for determining the EGCG content in black tea. In black tea, EGCG does not always have the major polyphenols while it does contain a considerable amount of ECG and theafiavin gallates (Ding et a/, 1992), from which gallic acid may be produced by tannase. However, our FIA method has the possibility of being a rapid method for the estimation of the astringency of black tea because high correlations have been reported between astringency and the content of EGCG, ECG and theaflavin gallates in black tea (Ding et al, 1992;Owuor & Obanda, 1995).…”

Section: Resultsmentioning

confidence: 99%

Flow Injection Analysis of (-)-Epigallocatechin Gallate in Green Tea Infusions with an Immobilized Tannase Reactor.

Horie

Mukai

Kohata

et al. 1997

FSTI

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A flow injection method to determine the concentrations of (-)-epigallocatechin gallate (EGCG) in tea infusions was developed. A bioreactor, packed with immobilized tannase, was connected to a pH-ISFET (Ion Sensitive Field Effect Transistor) electrode. The pH decrease, due to the gallic acid produced from EGCG by the enzyme reaction, was monitored by the electrode. The response of this system was linear between 50 mg/ I and 1,000 mg/ I of EGCG. The sample could be injected every 3 min. The concentrations of EGCG in green tea infusions obtained by this FIA method showed a fairly high correlation with those by HPLC.

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Influence of catechins and theaflavins on the astringent taste of black tea brews

Cited by 84 publications

References 11 publications

Flavanol Composition and Caffeine Content of Green Leaf as Quality Potential Indicators of Kenyan Black Teas

Flavanol Composition and Caffeine Content of Green Leaf as Quality Potential Indicators of Kenyan Black Teas

Spatial variability of theaflavins and thearubigins fractions and their impact on black tea quality

Flow Injection Analysis of (-)-Epigallocatechin Gallate in Green Tea Infusions with an Immobilized Tannase Reactor.

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