07-Plant beveages-4p

07-Plant beveages-4p - Caffeine & Beverages: ! Tea !...

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1 Caffeine & Beverages: Tea Coffee soft drinks Caffeine Caffeine is a bitter, white crystalline xanthine alkaloid that acts as a stimulant drug. Caffeine is found in varying quantities in the seeds, leaves, and fruit of some plants, where it acts as a natural pesticide that paralyzes and kills certain insects feeding on the plants. Pharmacology Inside the body caffeine acts through several mechanisms, but its most important effect is to counteract a substance called adenosine that naturally circulates at high levels throughout the body, and especially in the nervous system. In the brain, adenosine plays a generally protective role, part of which is to reduce neural activity levels or Opium versus Caffeine
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2 Tea: a representative herb The first cup of tea was an accident According to Chinese mythology, in 2737 BC the Chinese Emperor, Shen Nung, herbalist, was suffered from some poisonous grasses when the wind blew a few tea leaves before him. History of tea consumption 500B.C., Monks drank tea when they sat in meditation. 700A.D., Tang Dynasty, tea came available to the common people. 1000A.D., Song dynasty, delicate tea ceremony formed 1300A.D., Yuan Dynasty, tea ceremony back to simple and natural. 1650A.D., Qing Dynasty, complicated and delicate tea ceremony reformed. Opium Wars The First Opium War or the First Anglo- Chinese War was fought between the British East India Company and the Qing Dynasty in China from 1839 to 1842 with the aim of forcing China to import British opium. The Boston Tea Party whose tea was it? The East India Company
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3 Tea in China: Different types of tea Black tea ± fermented ² Oolong tea ± semi-fermented ² Green tea ± not fermented ² Fermentation of tea is more accurately described as oxidation which is caused by enzymes, since the process involves oxidation of phenolic compounds and not fermentation by microorganisms Tea is a drink made by infusing leaves of the tea plant Camellia sinensis in hot water Best quality tea is made from the bud and first two leaves of the growing shoot Strictly speaking, the term tea does not include herbal infusions such as chamomile and mint Green tea: Green tea has the longest history and still ranks first in output and variety today. Unfermented, Keeps most of the antioxidants like catechin People like its freshness and natural fragrance. Green leaf, clear water Preparation of green tea Long Jing tea Bi Luo Chun tea Denaturing the Enzymes!
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4 Black tea (red tea): Fermented Strong fragrances are developed during fermentation Green leaf turned to black (red) after fermentation 90% lost of antioxidants during processing. Wulong or Oolong tea:
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This note was uploaded on 03/10/2012 for the course FST 10 taught by Professor Jack during the Winter '08 term at UC Davis.

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07-Plant beveages-4p - Caffeine & Beverages: ! Tea !...

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