Tea Processing and its Impact on Catechins, Theaflavin and Thearubigin Formation

Shitandi, Anakalo; Ngure, Francis; Mahungu, Symon M.

doi:10.1016/b978-0-12-384937-3.00016-1

Cited by 7 publications

(6 citation statements)

References 37 publications

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“…2 There are six types of tea named green, yellow, oolong, white, Pu-erh and black tea based on the processing methods (on the basis of the degree of fermentation/oxidation) and sensorial characteristics. 3 Among them, the most consumed tea types can be classified as green tea (non-fermented), oolong tea (semi-fermented) and black tea (fully fermented) in the world. According to the types of tea, health benefits can vary depending on the polyphenols; especially catechin and phenolic acid composition.…”

Section: Introductionmentioning

confidence: 99%

Synchronous fluorescence spectroscopy combined with chemometrics for determination of total phenolic content and antioxidant activity in different tea types

Bilge

Özdemir

2020

J Sci Food Agric

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BACKGROUND The aim of this study is to monitor the antioxidant activity (AA) and total phenolic content (TPC) variations of different kinds of teas depending on the infusion temperature and time by using synchronous fluorescence spectroscopy (SFS) combined chemometrics as a rapid method. In this study, black tea, oolong tea, green tea, and green tea powder (matcha) samples were brewed at 80 °C and 96 °C for 2.5 to 30 min. Synchronous fluorescence spectra were recorded at different wavelength interval (Δλ) values for optimal models. AA and TPC of tea samples were determined by 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) assay and Folin–Ciocalteu methods as reference methods, respectively. Partial least square (PLS) method was used for correlation between reference methods and SFS method. RESULTS Results showed that SFS combined with chemometrics could be an alternative rapid way to monitor TPC and AA of teas with 0.932 and 0.918 of validation R2 values in fermented teas (black tea–oolong) while with 0.961 and 0.860 of validation R2 values in non‐fermented teas (green tea and green tea powder), respectively. Limit of detection (LOD) and root mean square error of prediction (RMSEP) values were ≤ 6.61 μg mL−1 and ≤ 17.42, respectively. CONCLUSION Based on the lowest R2 value (0.860) on TPC analysis, the proposed method is more appropriate for AA analysis of green tea and green tea powder. Furthermore, infusion time was more effective for obtaining different amounts of TPC and AA in fermented tea types while only infusion temperature was effective on green tea and green tea powder samples. Therefore, obtained calibration‐validation models gave better results for fermented tea types.

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Section: Introductionmentioning

confidence: 99%

Synchronous fluorescence spectroscopy combined with chemometrics for determination of total phenolic content and antioxidant activity in different tea types

Bilge

Özdemir

2020

J Sci Food Agric

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“…Tea from different regions has different capacities to oxidize catechins due to variations in the levels of polyphenol oxidase. The temperature of processing has an influence on oxidation as the uptake of oxygen increases up to 29 °C, where the enzyme activity reaches a peak (Shitandi et al, 2013) and the development of tea cream (haze) due to the complexing polyphenols with proteins and oxidized lipids formed during fermentation.…”

Section: Variation Of Haze Values Polyphenols and Caffeine Of Tea Ext...mentioning

confidence: 99%

Manufacturing of Low Haze Instant Tea Extracts Using Sri Lankan Broken Mixed Fannings (BMF) as Raw Materials

et al. 2022

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Haze or tea cream in instant tea significantly affects tea-based product manufacturing due to its impact in preparing unclouded tea infusions. The effect of pre-processing temperature of spray drying and cultivar elevation with haze development of instant tea production from Broken Mixed Fannings (BMF) was studied first time by analyzing Total polyphenol (TPC), caffeine content, yield and haze value in instant tea. Significant differences in haze and TPC percentages were observed across elevation categories of upcountry (86.1 NTU &16.33%), mid country (49.6 NTU &13.25%), and low country (29.7 NTU &11.94%) respectively. A strong positive correlation (0.992) was observed between TPC and haze level while a negative correlation showed between Caffeine and haze level (-0.967). However, there were no significant differences for haze, TPC and caffeine contents among tea estates in the same elevation category. The highest yield (27.17%) and lowest haze value (48.75 NTU) of instant tea were reported at the pre-process spray drying temperature of 70°C when compared with 40, 50, 60, 80 and 90°C. The method was validated in large-scale production and could be recommended as a proven methodology to reduce haze development and acquire a high yield of instant tea.

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“…Tea prepared from the leaves of Camellia sinensis species is one of the most world-wide favorite beverages and is consumed by over two-thirds of world's population. Based on the processing methods and sensory qualities of products, the six types of tea were defined as green, yellow, dark, oolong, white, and black teas [1] . Of which, three types are widely available on the global markets and more often cited as green tea, black tea and oolong tea [2] .…”

Section: Introductionmentioning

confidence: 99%

Camellia sinensis Tea and Cancer Risk: A Systematic Review

Le¹,

Lay²,

Wu³

et al. 2019

J. Ayu. Her. Med.

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Background: This article aims to provide currently available data and insight science knowledge on association between teas, their polyphenols and the risk of cancers including prostate, liver, lung, gastric, breast, colon and colorectal, esophageal, oral cavity, non-hodgkin's lymphoma, esdometrial, and pancreatic based on published studies by searching Pub Med and database of Web of Science belonging Institute for Science Information and secondary referencing qualified for inclusion. In addition, the molecular mechanisms of tea in cancer prevention also briefly discussed. The authors hope that this work will be help for readers, researches, reviewers, and editors who are interested in the related field of the Camellia sinensis tea studies.

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Tea Processing and its Impact on Catechins, Theaflavin and Thearubigin Formation

Cited by 7 publications

References 37 publications

Synchronous fluorescence spectroscopy combined with chemometrics for determination of total phenolic content and antioxidant activity in different tea types

Synchronous fluorescence spectroscopy combined with chemometrics for determination of total phenolic content and antioxidant activity in different tea types

Manufacturing of Low Haze Instant Tea Extracts Using Sri Lankan Broken Mixed Fannings (BMF) as Raw Materials

Camellia sinensis Tea and Cancer Risk: A Systematic Review

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