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Pu-erh Tea
''Pu'er'' or ''pu-erh'' is a variety of fermented tea traditionally produced in Yunnan Province, China. In the context of traditional Chinese tea production terminology, fermentation refers to microbial fermentation (called 'wet piling'), and is typically applied after the tea leaves have been sufficiently dried and rolled. As the tea undergoes controlled microbial fermentation, it also continues to oxidize, which is also controlled, until the desired flavors are reached. This process produces tea known as 黑茶 ''hēichá'' (lit. 'black tea') (which is different from the English-language ''black tea'' that is called 红茶 ''hóngchá'' (lit. 'red tea') in Chinese). Pu'er falls under a larger category of fermented teas commonly translated as ''dark teas''. Two main styles of pu'er production exist: a traditional, longer production process known as ''shēng'' (''raw'') pu'er; and a modern, accelerated production process known as ''shóu'' (''ripe'') pu'er. Pu'er traditionally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermented Tea
Fermented tea (also known as post-fermented tea or dark tea) is a class of tea that has undergone microbial fermentation, from several months to many years. The exposure of the tea leaves to humidity and oxygen during the process also causes endo-oxidation (derived from the tea-leaf enzymes themselves) and exo-oxidation (which is microbially catalysed). The tea leaves and the liquor made from them become darker with oxidation. Thus, the various kinds of fermented teas produced across China are also referred to as dark tea, not be confused with black tea. The most famous fermented tea is produced in Yunnan province. The fermentation of tea leaves alters their chemistry, affecting the organoleptic qualities of the tea made from them. Fermentation affects the smell of the tea and typically mellows its taste, reducing astringency and bitterness while improving mouthfeel and aftertaste. The microbes may also produce metabolites with health benefits. Additionally, substances lik ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Activity
Enzyme assays are laboratory methods for measuring enzymatic activity. They are vital for the study of enzyme kinetics and enzyme inhibition. Enzyme units The quantity or concentration of an enzyme can be expressed in molar amounts, as with any other chemical, or in terms of activity in enzyme units. Enzyme activity Enzyme activity is a measure of the quantity of active enzyme present and is thus dependent on various physical conditions, ''which should be specified''. It is calculated using the following formula: :\operatorname=\operatorname=\operatorname\times\operatorname where :\operatorname= Enzyme activity :\operatorname= Moles of substrate converted per unit time :\operatorname= Rate of the reaction :\operatorname= Reaction volume The SI unit is the katal, 1 katal = 1 mol s−1 (mole per second), but this is an excessively large unit. A more practical and commonly used value is enzyme unit (U) = 1 μmol min−1 (micromole per minute). 1 U corresponds to 16.67 nano ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pu-erh Tea (detail)
''Pu'er'' or ''pu-erh'' is a variety of fermented tea traditionally produced in Yunnan Province, China. In the context of traditional Chinese tea production terminology, fermentation refers to microbial fermentation (called 'wet piling'), and is typically applied after the tea leaves have been sufficiently dried and rolled. As the tea undergoes controlled microbial fermentation, it also continues to oxidize, which is also controlled, until the desired flavors are reached. This process produces tea known as 黑茶 ''hēichá'' (lit. 'black tea') (which is different from the English-language ''black tea'' that is called 红茶 ''hóngchá'' (lit. 'red tea') in Chinese). Pu'er falls under a larger category of fermented teas commonly translated as ''dark teas''. Two main styles of pu'er production exist: a traditional, longer production process known as ''shēng'' (''raw'') pu'er; and a modern, accelerated production process known as ''shóu'' (''ripe'') pu'er. Pu'er traditionally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Taipei, Taiwan
Taipei (), officially Taipei City, is the capital and a special municipality of the Republic of China (Taiwan). Located in Northern Taiwan, Taipei City is an enclave of the municipality of New Taipei City that sits about southwest of the northern port city of Keelung. Most of the city rests on the Taipei Basin, an ancient lakebed. The basin is bounded by the relatively narrow valleys of the Keelung and Xindian rivers, which join to form the Tamsui River along the city's western border. The city of Taipei is home to an estimated population of 2,646,204 (2019), forming the core part of the Taipei–Keelung metropolitan area, which includes the nearby cities of New Taipei and Keelung with a population of 7,047,559, the 40th most-populous urban area in the world—roughly one-third of Taiwanese citizens live in the metro district. The name "Taipei" can refer either to the whole metropolitan area or just the city itself. Taipei has been the seat of the ROC central govern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Free-radical
In chemistry, a radical, also known as a free radical, is an atom, molecule, or ion that has at least one unpaired valence electron. With some exceptions, these unpaired electrons make radicals highly chemically reactive. Many radicals spontaneously dimerize. Most organic radicals have short lifetimes. A notable example of a radical is the hydroxyl radical (HO·), a molecule that has one unpaired electron on the oxygen atom. Two other examples are triplet oxygen and triplet carbene (꞉) which have two unpaired electrons. Radicals may be generated in a number of ways, but typical methods involve redox reactions. Ionizing radiation, heat, electrical discharges, and electrolysis are known to produce radicals. Radicals are intermediates in many chemical reactions, more so than is apparent from the balanced equations. Radicals are important in combustion, atmospheric chemistry, polymerization, plasma chemistry, biochemistry, and many other chemical processes. A majority of na ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fermentation (food)
In food processing, fermentation is the conversion of carbohydrates to alcohol or organic acids using microorganisms—yeasts or bacteria—under anaerobic (oxygen-free) conditions. Fermentation usually implies that the action of microorganisms is desired. The science of fermentation is known as zymology or zymurgy. The term "fermentation" sometimes refers specifically to the chemical conversion of sugars into ethanol, producing alcoholic drinks such as wine, beer, and cider. However, similar processes take place in the leavening of bread (CO2 produced by yeast activity), and in the preservation of sour foods with the production of lactic acid, such as in sauerkraut and yogurt. Other widely consumed fermented foods include vinegar, olives, and cheese. More localised foods prepared by fermentation may also be based on beans, grain, vegetables, fruit, honey, dairy products, and fish. History and prehistory Natural fermentation precedes human history. Since ancient times, h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camellia Sinensis Var
''Camellia'' (pronounced or ) is a genus of flowering plants in the family Theaceae. They are found in eastern and southern Asia, from the Himalayas east to Japan and Indonesia. There are more than 220 described species, with some controversy over the exact number, and also around 3,000 hybrids. The genus was named by Linnaeus after the Jesuit botanist Georg Joseph Kamel, who worked in the Philippines and described a species of camellia (although Linnaeus did not refer to Kamel's account when discussing the genus). Of economic importance in East Asia, Southeast Asia, and the Indian subcontinent, leaves of '' C. sinensis'' are processed to create the popular beverage tea. The ornamental '' C. japonica'', '' C. sasanqua'' and their hybrids are the source of hundreds of garden cultivars. '' C. oleifera'' produces tea seed oil, used in cooking and cosmetics. Descriptions Camellias are evergreen shrubs or small trees up to tall. Their leaves are alternately arranged, simple, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Green Tea
Green tea is a type of tea that is made from '' Camellia sinensis'' leaves and buds that have not undergone the same withering and oxidation process which is used to make oolong teas and black teas. Green tea originated in China, and since then its production and manufacture has spread to other countries in East Asia. Several varieties of green tea exist, which differ substantially based on the variety of ''C. sinensis'' used, growing conditions, horticultural methods, production processing, and time of harvest. The two main components unique to green tea are "catechins" and "theanine," and the health effects of these components are attracting a great deal of attention in Japan and abroad. History Tea consumption has its legendary origins in China during the reign of mythological Emperor Shennong. A book written by Lu Yu in 618–907 AD (Tang dynasty), ''The Classic of Tea'' (), is considered important in green tea history. The ''Kissa Yōjōki'' (喫茶養生記 ''Book ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxidation
Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a decrease in the oxidation state. There are two classes of redox reactions: * ''Electron-transfer'' – Only one (usually) electron flows from the reducing agent to the oxidant. This type of redox reaction is often discussed in terms of redox couples and electrode potentials. * ''Atom transfer'' – An atom transfers from one substrate to another. For example, in the rusting of iron, the oxidation state of iron atoms increases as the iron converts to an oxide, and simultaneously the oxidation state of oxygen decreases as it accepts electrons released by the iron. Although oxidation reactions are commonly associated with the formation of oxides, other chemical species can serve the same function. In hydrogenation, C=C (and other) bonds ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tea Processing
Tea processing is the method in which the leaves from the tea plant '' Camellia sinensis'' are transformed into the dried leaves for brewing tea. The categories of tea are distinguished by the processing they undergo. In its most general form, tea processing involves different manners and degrees of oxidation of the leaves, stopping the oxidation, forming the tea and drying it. The innate flavor of the dried tea leaves is determined by the type of cultivar of the tea bush, the quality of the plucked tea leaves, and the manner and quality of the production processing they undergo. After processing, a tea may be blended with other teas or mixed with flavourants to alter the flavor of the final tea. When producing black, pu'erh and oolong teas there is an additional purpose of processing: to encourage oxidization, which further develops flavour and aroma compounds. History The history of tea processing corresponds intimately with the role that tea played in Chinese society and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Appellation
An appellation is a legally defined and protected geographical indication primarily used to identify where the grapes for a wine were grown, although other types of food often have appellations as well. Restrictions other than geographical boundaries, such as what grapes may be grown, maximum grape yields, alcohol level, and other quality factors may also apply before an appellation name may legally appear on a wine bottle label. The rules that govern appellations are dependent on the country in which the wine was produced. History The tradition of wine appellation is very old. The oldest references are to be found in the Bible, where ''wine of Samaria'', ''wine of Carmel'', ''wine of Jezreel'', or ''wine of Helbon'' are mentioned. This tradition of appellation continued throughout the Antiquity and the Middle Ages, though without any officially sanctioned rules. Historically, the world's first exclusive (protected) vineyard zone was introduced in Chianti, Italy in 1716 and th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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