Transcriptome and Metabolic Profiling Unveiled Roles of Peroxidases in Theaflavin Production in Black Tea Processing and Determination of Tea Processing Suitability

2020 ◽  
Vol 68 (11) ◽  
pp. 3528-3538 ◽  
Author(s):  
Gaoyang Zhang ◽  
Jihong Yang ◽  
Dandan Cui ◽  
Dandan Zhao ◽  
Yingying Li ◽  
...  
Keyword(s):  
Metabolic Profiling ◽  
Black Tea

Determination of flavonol glycosides in green tea, oolong tea and black tea by UHPLC compared to HPLC

2015 ◽  
Vol 183 ◽  
pp. 30-35 ◽  
Author(s):  
Heyuan Jiang ◽  
Ulrich H. Engelhardt ◽  
Claudia Thräne ◽  
Beate Maiwald ◽  
Janina Stark
Keyword(s):  
Green Tea ◽  
Black Tea ◽  
Flavonol Glycosides ◽  
Oolong Tea

scholarly journals Determination of Oxalate and Some Inorganic Anions in Green and Black Tea

2013 ◽  
Vol 67 (4-5) ◽  
pp. 429-432 ◽  
Author(s):  
Elena Yusenko ◽  
Evgeniya Polyntseva ◽  
Anna Lyzhova ◽  
Olga Kalyakina
Keyword(s):  
Oxalic Acid ◽  
Green Tea ◽  
Ion Chromatography ◽  
Black Tea ◽  
Inorganic Anions ◽  
Sample Treatment ◽  
Oxalate Concentration ◽  
Relative Standard ◽  
Oxalate Ions

Abstract Oxalate concentration differs in various daily consumed food products. The role of oxalic acid in the human body is very significant, as its compounds are responsible for the stability of biological membranes. However, insoluble calcium and magnesium oxalates can be accumulated in the body in the form of kidney stones. Oxalate concentration has been measured by high performance liquid, gas after derivatization and ion chromatography (IC). The most effective method for the simultaneous determination of oxalate and inorganic anions is ion chromatography with conductometric detection. Here, we report the results of the measurement of oxalic acid in bleak and green tea samples. Separation was performed by IC on an anion-exchange column Shodex IC SI-90 with surface-layer sorbent and conductimetric detection. The main analytical features of the method were: limit of detection of oxalic acid 0.03 mg/l, linear range 0.1-20 mg/l, correlation 0.9998, relative standard deviation 1%. The method did not need specific sample treatment and was successfully applied to the analysis of black and green tea samples. Oxalic acid was determined in the ranges 16.7-84 mg/l for green tea and 63-116 mg/l for black tea. Green tea contained lower oxalate ions concentration than black tea. The IC method has a lower detection limit for oxalate ions than HPLS and GC, ten and two times less, respectively

scholarly journals Determination of the Chemical Composition of Tea by Chromatographic Methods: A Review

2015 ◽  
Vol 4 (3) ◽  
pp. 56 ◽  
Author(s):  
Alexandr Ya Yashin ◽  
Boris V. Nemzer ◽  
Emilie Combet ◽  
Yakov I. Yashin
Keyword(s):  
Chemical Composition ◽  
Volatile Compounds ◽  
Black Tea ◽  
Storage Conditions ◽  
Organoleptic Evaluation ◽  
Chromatographic Methods ◽  
Tea Quality ◽  
Processing And Storage ◽  
And Storage

<p>Despite the fact that mankind has been drinking tea for more than 5000 years, its chemical composition has been studied only in recent decades. These studies are primarily carried out using chromatographic methods. This review summarizes the latest information regarding the chemical composition of different tea grades by different chromatographic methods, which has not previously been reviewed in the same scope. Over the last 40 years, the qualitative and quantitative analyses of high volatile compounds were determined by GC and GC/MS. The main components responsible for aroma of green and black tea were revealed, and the low volatile compounds basically were determined by HPLC and LC/MS methods. Most studies focusing on the determination of catechins and caffeine in various teas (green, oolong, black and pu-erh) involved HPLC analysis.</p> <p>Knowledge of tea chemical composition helps in assessing its quality on the one hand, and helps to monitor and manage its growing, processing, and storage conditions on the other. In particular, this knowledge has enabled to establish the relationships between the chemical composition of tea and its properties by identifying the tea constituents which determine its aroma and taste. Therefore, assessment of tea quality does not only rely on subjective organoleptic evaluation, but also on objective physical and chemical methods, with extra determination of tea components most beneficial to human health. With this knowledge, the nutritional value of tea may be increased, and tea quality improved by providing via optimization of the growing, processing, and storage conditions.</p>

Determination of fluoride levels after brewing in three Turkish black tea products

2013 ◽  
Vol 1 (3) ◽  
pp. 63
Author(s):  
MuratSelim Botsali ◽  
Yagmur Sener ◽  
Sibel Yildirim
Keyword(s):  
Black Tea
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