Biochemical conversion and flavor chemistry of Congou black tea: From fresh leaves to tea infusions

2021 ◽  
Author(s):  
Jia Li ◽  
Haibo Yuan ◽  
Yongwen Jiang
Keyword(s):  
Black Tea ◽  
Biochemical Conversion ◽  
Tea Infusions ◽  
Flavor Chemistry

scholarly journals Black Tea Source, Production, and Consumption: Assessment of Health Risks of Fluoride Intake in New Zealand

2017 ◽  
Vol 2017 ◽  
pp. 1-27 ◽  
Author(s):  
Declan T. Waugh ◽  
Michael Godfrey ◽  
Hardy Limeback ◽  
William Potter
Keyword(s):  
New Zealand ◽  
Black Tea ◽  
Fluoride Content ◽  
The Public ◽  
Fluoride Intake ◽  
Production And Consumption ◽  
Tea Infusions ◽  
High Prevalence ◽  
Consumption Rates ◽  
Fluoride Ion Selective Electrode

In countries with fluoridation of public water, it is imperative to determine other dietary sources of fluoride intake to reduce the public health risk of chronic exposure. New Zealand has one of the highest per capita consumption rates of black tea internationally and is one of the few countries to artificially fluoridate public water; yet no information is available to consumers on the fluoride levels in tea products. In this study, we determined the contribution of black tea as a source of dietary fluoride intake by measuring the fluoride content in 18 brands of commercially available products in New Zealand. Fluoride concentrations were measured by potentiometric method with a fluoride ion-selective electrode and the contribution of black tea to Adequate Intake (AI) and Tolerable Upper Intake Level (UL) was calculated for a range of consumption scenarios. We examined factors that influence the fluoride content in manufactured tea and tea infusions, as well as temporal changes in fluoride exposure from black tea. We review the international evidence regarding chronic fluoride intake and its association with chronic pain, arthritic disease, and musculoskeletal disorders and provide insights into possible association between fluoride intake and the high prevalence of these disorders in New Zealand.

scholarly journals Green Tea Daily Consume Reduced Free Radicals on Moderate Smokers

2018 ◽  
Vol 2 (2) ◽  
pp. 39
Author(s):  
Rosyanne Kushargina ◽  
Rimbawan Rimbawan ◽  
Budi Setiawan
Keyword(s):  
Free Radicals ◽  
Experimental Design ◽  
Antioxidant Capacity ◽  
Green Tea ◽  
Black Tea ◽  
Intervention Period ◽  
Tea Leaves ◽  
Positive Effects ◽  
Tea Infusions ◽  
Total Antioxidant

<p><em>Smoking </em><em>can </em><em>enhance </em><em>free radicals on blood plasma. Many previous studies proved that tea is a source of antioxidants which might reduce free radicals. Green tea is known to have the higher antioxidant capacity compared to </em><em>black tea</em><em>.</em><em> This study aim</em><em>s </em><em>to analyze the effect </em><em>of green tea on reduction of free radicals on moderate smokers</em><em>, using a pre-post experimental design. </em><em>Green tea infusions were prepared with commercially available dried tea leaves (Green Tea Gamboeng Series) from the </em><em>Research</em><em> </em><em>Centers of Tea</em><em> </em><em>and</em><em> </em><em>Cinchona</em><em> Gambung, West Java. </em><em>Nine moderate smokers (11-21 cig/day) aged 30-45 years were instructed to drink 200 ml green tea three times a day for </em><em>four</em><em> weeks. Total Antioxidant Capacity (TAC) of blood serum was measured at baseline and after four weeks intervention period. The level of TAC significantly increased from 1.18 m mol/L to 1.34 m mol/L after </em><em>four</em><em> weeks intervention (P=0.000). These results prove that drinking 200 ml of green tea </em><em>three</em><em> times a day for </em><em>four</em><em> weeks has a significant benefit reduc</em><em>ing f</em><em>ree radicals of moderate smokers. Moderate smokers are advised to consume green tea continuously to sustain these positive effects.</em><em></em></p>

scholarly journals A predictive approach to the antioxidant capacity assessment of green and black tea infusions

2020 ◽  
Author(s):  
Małgorzata Muzolf-Panek ◽  
Anna Kaczmarek ◽  
Anna Gliszczyńska-Świgło
Keyword(s):  
Data Mining ◽  
Antioxidant Activity ◽  
Antioxidant Capacity ◽  
Black Tea ◽  
Multivariate Adaptive Regression Splines ◽  
Total Phenolic ◽  
Data Mining Techniques ◽  
Tea Quality ◽  
Tea Infusions ◽  
Green And Black Tea

AbstractContemporary consumers drink significant amounts of tea because of its health–benefits mainly associated to the presence of polyphenols with high antioxidant activity. Therefore, the information how to obtain tea infusion of the highest quality, i.e. with high antioxidant capacity is needed. In this study, the various models for the prediction of total polyphenols and antioxidant activity of green and black tea infusions were developed and compared. Three mathematical equations: Spiro’s, Peleg’s and logarithmic, and two data mining techniques: multivariate adaptive regression splines (MARS) and artificial neural networks (ANNs) were used to build the predictive models. The results obtained show that Spiro’s model could be used for the prediction of green tea quality expressed as total phenolic content or the antioxidant activity (determination coefficients above 0.99), whereas Peleg’s model is more suitable for black tea quality prediction (determination coefficients above 0.99). Data mining techniques (MARS and ANNs) enable to create models fast and of simple application with very good acceptability (determination coefficients above 0.99).

scholarly journals Influence of phenolic compounds on sensory parameters of tea infusions

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S195-S198
Author(s):  
P. Košulič ◽  
J. Pokorný ◽  
Z. Panovská
Keyword(s):  
Phenolic Compounds ◽  
Green Tea ◽  
Black Tea ◽  
Total Polyphenols ◽  
Iso Standards ◽  
Tea Infusions ◽  
Sensory Parameters

A set of 9 black teas and 10 green teas were analyzed. Sensory parameters of tea infusions were correlated with the content of total polyphenols (determined after Folin and Ciocalteu) and sensory parameters (determined after ISO standards). Total polyphenols affect both the astringency and the bitterness of green tea and black tea infusions. The relations are mainly semilogarithmic, but very close to linear. Sucrose decreased the astringency by 30–40%, and the bitterness was suppressed still more.

Estimation of black tea quality by analysis of chemical composition and colour difference of tea infusions

2003 ◽  
Vol 80 (2) ◽  
pp. 283-290 ◽  
Author(s):  
Yuerong Liang ◽  
Jianliang Lu ◽  
Lingyun Zhang ◽  
Shan Wu ◽  
Ying Wu
Keyword(s):  
Chemical Composition ◽  
Black Tea ◽  
Colour Difference ◽  
Tea Quality ◽  
Tea Infusions

Influence of brewing pots on mineral content of black tea infusions

2013 ◽  
Vol 38 (1) ◽  
pp. 57-62
Author(s):  
Muhittin Tayfur ◽  
Nilgun Karaagaoglu ◽  
Sevil Basoglu ◽  
Seyit Mehmet Mercanligil
Keyword(s):  
Mineral Content ◽  
Black Tea ◽  
Tea Infusions

Determination of lemon and carbonate effects on caffeine content of various teas and investigation of daily caffeine intakes / Çeşitli çayların içerdikleri kafein miktarlarına limon ve karbonatın etkisi ve günlük alım miktarlarının incelenmesi

2016 ◽  
Vol 41 (5) ◽  
Author(s):  
Funda Demir ◽  
Azmi Seyhun Kıpçak ◽  
Özgül Dere Özdemir ◽  
Mehmet Burçin Pişkin ◽  
Emek Möröydor Derun
Keyword(s):  
Green Tea ◽  
Camellia Sinensis ◽  
Black Tea ◽  
Daily Maximum ◽  
Caffeine Content ◽  
Tea Infusions ◽  
Health Field

AbstractObjective: Tea (Camellia sinensis), has been used for health field in thousands of years. Caffeine is one of the key component in tea and investigation of caffeine is a popular working subject among the researches. The novelty of this study is not only the determination of the caffeine contents of the teas, but also how addition of lemon and carbonate effects the caffeine contents. Another aim of the study is the investigation of the daily caffeine intakes from teas.Methods: Tea infusions were prepared and caffeine contents were extracted by using chloroform and determined by UV-Vis Spectrophotometer. For lemon and carbonate addition experiments, lemon was added before the caffeine analysis and carbonate was added at the beginning.Results: Maximum caffeine contents from highest to lowest were seen in black, earl grey and green in classic teas; fennel, mint and sage in herbal teas; lemon, apple and rosehip in fruit teas. With lemon addition caffeine contents were increased except green tea and with carbonate addition caffeine contents were decreased except black and fennel tea. Daily caffeine intakes are found between 32.10% (green tea with carbonate) - 77.20% (black tea with lemon), 1.85% (sage tea with carbonate) - 4.05% (fennel tea with lemon) and 2.10% (rosehip with carbonate) - 4.00% (lemon tea with lemon) in classic, herbal and fruit teas, respectively.Conclusion: The significance of this study indicates that herbal and fruit teas contain caffeine, which is assumed zero in literature. The caffeine amount of herbal teas (20.79±0.36-30.68±0.63 ppm) were found barely higher than the fruit teas (22.87±0.54-28.54±0.75 ppm) but daily maximum caffeine intakes were found less than 5%. The daily maximum caffeine intakes were found in the teas as 525.36±2.84-20.79±0.36 ppm, where lemon addition increased to 617.90±3.54-22.97±0.58 ppm and carbonate addition decreased to 488.54±2.05-16.84±0.28 ppm.

scholarly journals Black Tea Samples Origin Discrimination Using Analytical Investigations of Secondary Metabolites, Antiradical Scavenging Activity and Chemometric Approach

Molecules ◽  
2018 ◽  
Vol 23 (3) ◽  
pp. 513 ◽  
Author(s):  
Wojciech Koch ◽  
Wirginia Kukula-Koch ◽  
Łukasz Komsta
Keyword(s):  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Principal Component ◽  
Black Tea ◽  
Epicatechin Gallate ◽  
Tea Infusions ◽  
Chemometric Approach ◽  
Dpph Scavenging ◽  
Dpph Radical Scavenging ◽  
Comprehensive Study

A comprehensive study on the composition and antioxidant properties of black tea samples with a chemometric approach was performed via LC-ESI-Q-TOF-MS, DPPH radical scavenging assay, and Folin–Ciocalteu assay (TPC). Marked differences between the teas from seven different countries (China, India, Iran, Japan, Kenya, Nepal, Sri Lanka) were shown. The Indian samples demonstrated the highest total catechin content (184.8 mg/100 mL), the largest TPC and DPPH scavenging potential (58.2 mg/100 mL and 84.5%, respectively). The applied principal component analysis (PCA) and ANOVA revealed several correlations between the level of catechins in tea infusions. EC (epicatechin), ECG (epicatechin gallate), EGC (epigallocatechin), and EGCG (epigallocatechin-3-gallate) content was not correlated with DPPH, gallic acid, and TPC; however, a strong correlation of EC and ECG between themselves and a negative correlation of these two catechins with EGCG and EGC was noted. Interestingly, simple catechins were not found to be responsible for antioxidant properties of the black teas. The samples collected in the higher altitudes were similar.

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