Tracing the trans-Pacific tea trade from the eighteenth century onward, Green with Milk and Sugar shows how the interconnections between Japan and the United States have influenced the daily habits ...of people in both countries. Robert Hellyer explores the forgotten American penchant for Japanese green tea and how it shaped Japanese tastes.
Shiqiang Wei
Angewandte Chemie International Edition,
February 12, 2018, Letnik:
57, Številka:
7
Journal Article
Recenzirano
“My favorite drink is Chinese tea. My science “heroes” are Isaac Newton and Albert Einstein ...” This and more about Shiqiang Wei can be found on page 1744.
In this paper, the differentiation of green, black, Oolong, white, and Pu-erh teas has been carried out according to their free amino acid contents. Alanine, arginine, asparagine, aspartic acid, ...glutamic acid, isoleucine, histidine, leucine, phenylalanine, serine, theanine, threonine, and tyrosine have been determined by liquid chromatography with derivatization with o-phthalaldehyde and fluorescence detection. The chromatographic separation was achieved with a Hypersil ODS column and gradient elution. The amino acid contents were used as chemometric descriptors for classification purposes of different tea varieties. Principal component analysis, k-nearest neighbors, linear discriminant analysis, and artificial neural networks were applied to differentiate tea varieties. Using back-propagation multilayer perceptron artificial neural networks, 100% success in the classification was obtained. The most differentiating amino acids were glutamic acid, asparagine, serine, alanine, leucine, and isoleucine. Keywords: Tea; amino acids; reversed phase high-performance liquid chromatography; derivatization; chemometrics; pattern recognition
Tea, made from the leaves of the Camellia senenisis plant, is the second most consumed beverage worldwide after water. Accumulating evidence from cellular, animal, epidemiological and clinical ...studies have linked tea consumption to various health benefits, such as chemoprevention of cancers, chronic inflammation, heart and liver diseases, diabetes, neurodegenerative diseases, etc. Although such health benefits have not been consistently observed in some intervention trials, positive results from clinical trials have provided direct evidence supporting the cancer-protective effect of green tea. In addition, numerous mechanisms of action have been suggested to contribute to tea’s disease-preventive effects. Furthermore, effects of the processing and storage of tea, as well as additives on tea’s properties have been investigated.
Change they can't believe in Parker, Christopher S; Parker, Christopher S; Barreto, Matt A
2013., 20141026, 2013-05-21, 2015-01-01
eBook
Are Tea Party supporters merely a group of conservative citizens concerned about government spending? Or are they racists who refuse to accept Barack Obama as their president because he's not ...white?Change They Can't Believe Inoffers an alternative argument-that the Tea Party is driven by the reemergence of a reactionary movement in American politics that is fueled by a fear that America has changed for the worse. Providing a range of original evidence and rich portraits of party sympathizers as well as activists, Christopher Parker and Matt Barreto show that the perception that America is in danger directly informs how Tea Party supporters think and act.
In a new afterword, Parker and Barreto reflect on the Tea Party's recent initiatives, including the 2013 government shutdown, and evaluate their prospects for the 2016 election.
Tea (
Camellia sinensis L) is one of the most widely popular nonalcoholic beverage, consumed by over two-thirds of the world's population due to its medicinal, refreshing and mild stimulant effects. ...Mainly four types of made tea viz., black or red, oolong, green and white are used for tea infusion (water extract from fermented tea leaf) worldwide. Tea plays a major role in terms of the intake of a number of nutritional trace elements in humans. Besides essential macro- and microelements, experimental studies have demonstrated that the accumulation of significant amount of excess nonessential trace elements in tea leaves may eventually increase the metal body burden in humans. Different literatures have indicated that among different trace elements, levels of aluminium (Al), arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), fluoride (F) manganese (Mn), and nickel (Ni) in different tea infusions were 0.06–16.82
mg
L
−
1
, trace—1.53
μg
L
−
1
, trace—0.79
μg
L
−
1
, below detectable limit—43.2
μg
L
−
1
, 0.02–40.0
mg L
−
1
, 0.2–4.54
mg
L
−
1
, 0.1–250
mg
L
−
1
and BDL—0.16
mg
L
−
1
, respectively. It has also been reported that in some of the tea infusions, toxic metals exceed the maximum permissible limits stipulated for different countries. In the present review, an attempt has been made to update and evaluate the knowledge of the presence of some selected trace elements in tea leaves, made tea and tea infusion, based on the available literature. Existing reports suggested that the presence of trace elements in green tea is lower than the black tea in most cases. However, the available literatures still appear to have some limits and may need more detailed investigations before reaching the conclusions.
Volatile compounds are important components of tea aroma, a key attribute of sensory quality. The present review examines the formation of aromatic volatiles of various kinds of teas and factors ...influencing the formation of tea volatiles, including tea cultivar, growing environment and agronomic practices, processing method and storage of tea. The determination of tea volatiles and the relationship of active-aroma volatiles with the sensory qualities of tea are also discussed in the present paper.
Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Tea polyphenols which includes (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), ...(-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG) and theaflavin (TF) have been reported to possess various biological activities. The present study focused on changes in content of organic acid and tea polyphenols in kombucha tea prepared from green tea (GTK), black tea (BTK) and tea manufacture waste (TWK) during fermentation. Concentration of acetic acid has reached maximum up to 9.5
g/l in GTK on 15th day and glucuronic acid concentration was reached maximum upto 2.3
g/l in BTK on 12th day of fermentation. Very less concentration of lactic acid was observed during the fermentation period and citric acid was detected only on 3rd day of fermentation in GTK and BTK but not in TWK. When compared to BTK and TWK very less degradation of EGCG (18%) and ECG (23%) was observed in GTK. TF and thearubigen (TR) were relatively stable when compared to epicatechin isomers. The biodegradation of tea catechins, TF and TR during kombucha fermentation might be due to some unknown enzymes excreted by yeasts and bacteria in kombucha culture.
Tea (
) and herbal tea have been recognized as rich sources of bioactive constituents with the ability to exert antioxidant actions. The aims of this study were to analyze phenolic, carotenoid and ...saccharide contents in a set of Vietnamese tea and herbal tea and compare the results with those of green and black teas marketed in the U.S. In total, 27 phenolics, six carotenoids and chlorophylls, and three saccharides were quantitatively identified. Catechins, quercetin glycosides and chlorogenic acid were the predominating phenolics in the teas, with the concentrations following the order: jasmine/green teas > oolong tea > black tea. Lutein was the dominant carotenoid in the teas and its concentrations were generally found to be higher in the jasmine and green teas than in the oolong and black teas. The study showed that the green teas originating in Vietnam had much higher levels of phenolics and carotenoids than their counterparts stemming from another country. The application of partial least squares discriminant analysis (PLS-DA) as a chemometric tool was able to differentiate phenolic profiles between methanolic extracts and tea infusions. Through principal component analysis (PCA), the similarities and dissimilarities among the jasmine, green, oolong, black teas and herbal teas were depicted.
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