Epimerisation of catechins in green tea infusions

Wang, H

doi:10.1016/s0308-8146(00)00099-6

Cited by 187 publications

(143 citation statements)

References 13 publications

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…It was also found that the concentration of catechin increased at a higher rate when the RH was elevated, probably due to limited access of oxygen to roasted material. This assumption agrees with observations of Wang and Helliwell [29] who noticed that at high temperature, in particular under anaerobic conditions, more catechins, being (−) epiforms (2R, 3R), could undergo conversion to suitable (−) forms (2S, 3R). Similar conclusions were reported by Tamrin et al [18] who reported that during cocoa powder roasting with vacuum (45.6 and 60.8 cmHg) at temperatures from 100 to 120 °C, the low oxygen in the roasting space may slow the oxidation processes of the catechins.…”

Section: Resultssupporting

confidence: 93%

Changes in the flavan-3-ols, anthocyanins, and flavanols composition of cocoa beans of different Theobroma cacao L. groups affected by roasting conditions

Oracz

Nebesny

Żyżelewicz

2015

Eur Food Res Technol

View full text Add to dashboard Cite

Section: Resultssupporting

confidence: 93%

Changes in the flavan-3-ols, anthocyanins, and flavanols composition of cocoa beans of different Theobroma cacao L. groups affected by roasting conditions

Oracz

Nebesny

Żyżelewicz

2015

Eur Food Res Technol

View full text Add to dashboard Cite

“…The effect of water type on the ECG content was in agreement with the trend observed with EGCG, EGC and EC, but the differences were not significant (p [ 0.05). In general, the catechin content was the highest in tea infusions made with pure water, intermediate with spring water, and the lowest with tap water, consistent with a previous report that catechins were more easily epimerised and then rapidly degraded in infusions prepared with tap water, compared with purified water (Wang and Helliwell 2000), and also with the observation that green tea extracts prepared with tap water contained less polyphenols (Zhou et al 2009). This could be explained by the complexity of ions in tap water including Ca 2?…”

Section: Effect Of Water Quality On Individual Catechin Contentsupporting

confidence: 89%

“…, K ? , or by differences in pH between tap and purified water (Wang and Helliwell 2000). Ions such as Ca 2?…”

Section: Effect Of Water Quality On Individual Catechin Contentmentioning

confidence: 99%

Effect of water quality on the main components in Fuding white tea infusions

Zhang

Jiang

et al. 2017

J Food Sci Technol

View full text Add to dashboard Cite

The aim of this study was to investigate the effect of water quality on the main components in Fuding white tea infusions, including catechins, caffeine, theanine and free amino acids. Pure, tap and spring water were tested, and water quality was found to have a distinct effect on the main compounds extracted. Pure water, which was weakly acidic and low in dissolved ions, achieved the highest catechin content, whereas caffeine and theanine, and amino acids, were higher in infusions made with spring and tap water, respectively. Sensory evaluation was performed to evaluate infusion colour, taste and aroma, and sensory quality was similarly influenced by water type, due primarily to differences in dissolved ions. Pure water was more suitable for brewing white tea with superior colour, aroma and taste.

show abstract

“…These results indicate that excessive extraction temperatures above 801C could lead to an increased epimerization of the epistructured catechins to non-epistructured catechins. This has also been observed in previous studies [16,17], which found that epimerisation from the epistructured to the non-epistructured catechins happened predominantly when the brewing temperature was above 801C. Therefore, care should be taken to prevent exposure of the catechins to temperatures above 801C during hot water extractions.…”

Section: Effect Of Extraction Temperaturesupporting

confidence: 82%

Optimizing conditions for the extraction of catechins from green tea using hot water

Vuong

Golding

Stathopoulos

et al. 2011

J of Separation Science

179

118

View full text Add to dashboard Cite

Six different factors involved in the extraction of catechins from green tea using water were examined for their impact on the yield of catechins and on the efficiency of water use. The best temperature and time combination for catechin extraction was at 80°C for 30 min. The yield of catechins was also optimal with a tea particle size of 1 mm, a brewing solution pH <6 and a tea-to-water ratio at 50:1 (mL/g). In terms of efficient use of water in a single extraction, a water-to-tea ratio of 20:1 (mL/g) gave the best results; 2.5 times less water was used per gram of green tea. At the water-to-tea ratio of 20:1 mL/g, the highest yield of catechins per gram of green tea was achieved by extracting the same sample of green tea twice. However, for the most efficient use of water, the best extraction was found to be once at a water-to-tea ratio of 12:1 (mL/g) and once at a water-to-tea ratio of 8:1 (mL/g). Therefore, all six of the factors investigated had an impact on the yield of catechins extracted from green tea using water and two had an impact on the efficiency of water use.

show abstract

Epimerisation of catechins in green tea infusions

Cited by 187 publications

References 13 publications

Changes in the flavan-3-ols, anthocyanins, and flavanols composition of cocoa beans of different Theobroma cacao L. groups affected by roasting conditions

Changes in the flavan-3-ols, anthocyanins, and flavanols composition of cocoa beans of different Theobroma cacao L. groups affected by roasting conditions

Effect of water quality on the main components in Fuding white tea infusions

Optimizing conditions for the extraction of catechins from green tea using hot water

Contact Info

Product

Resources

About