Download - Beverages- Tea and Coffee
BEVERAGESTEA & COFFEE
Afshan P T
A drink, or beverage, is a liquid which is specifically prepared for human consumption. In addition to filling a basic human need, beverages form part of the culture of human society.
Types of beverage
Soft drinks Hot beverages Alcoholic beverages Non-alcoholic beverages Miscellaneous
Non-alcoholic beverages
Non-alcoholic beverages are drinks that usually contain alcohol, such as beer and wine, but contain less than 0.5% alcohol by volume. This category includes low-alcohol beer, non-alcoholicwine, and apple cider.
Soft drinks
Beverages like colas, sparkling water, iced tea, lemonade, squash, and fruit punch are among the most common types of soft drinks, while hot chocolate, hot tea, coffee, milk, tap water, alcohol, andmilkshakes do not fall into this classification. Many carbonated soft drinks are optionally available in versions sweetened with sugars or with non-caloric sweeteners.
Hot beverages
A hot beverage is any beverage which is normally served heated. This may be through the addition of a heated liquid, such as water or milk, or by directly heating the beverage itself.
Some examples of hot beverages are: Coffee-based beverages Hot chocolate Tea-based beverages
Miscellaneous
Some substances may be called either food or drink, and accordingly may be eaten with a spoon or drunk, depending upon their thickness and solutes.
Buttermilk Soup Yogurt
TEA
Plant
Camellia sinensis Two main varieties
C.sinensis var. sinensis C. sinensis var. assaminca
Family: Theaceae Mainly grown in subtropics and
mountainous regions of tropics It can be grown from above sea level
and just over 2100 meters
Tea is the agricultural product of the leaves, leaf buds, and internodes of the Camellia sinensis plant, prepared and cured by various methods. "Tea" also refers to the aromatic beverage prepared from the cured leaves by combination with hot or boiling water,[2] and is the common name for the Camellia sinensis plant itself.
Although tea contains various types of polyphenols, "contrary to widespread belief, tea does not contain tannic acid".
After water, tea is the most widely-consumed beverage in the world.[4] It has a cooling, slightly bitter, astringent flavour which many enjoy
There are at least six varieties of tea: white, yellow, green, oolong, black and pu-erh. All teas are made from the same species of plant, though different varieties may be used, and the leaves are processed differently, and, in the case of fine white tea, grown differently. Pu-erh tea, a post-fermented tea, is also often used medicinally
Chinese tea – Green tea, flowery flavour and light
Assam tea – Black tea, “heavy” stronger
Green tea: Freshly picked leaves are steamed and dried without the withering stage and thus retain a faint but distinctive ‘grassy’ taste, and their green color.
The term "herbal tea" usually refers to an infusion or tisane of leaves, flowers, fruit, herbs or other plant material that contains no Camellia sinensis.[8] The term "red tea" refers to an infusion made from either black tea (mainly in Chinese, Korean, Japanese and other East Asian languages) or theSouth African rooibos plant (containing no Camellia sinensis).
History
The Chinese believe that tea was first drunk during the reign of Shen Nung (The Divine healer) during 2737 BC
History of tea in India
The cultivation and brewing of tea in India has a long history of applications in traditional systems of medicine and for consumption. Tea had been known for millennia in India as a medicinal plant. The consumption of tea in India was first clearly documented in the ancient epic Ramayana (500 BC). Research shows that tea is introduced to eastern and northern India, and was cultivated and consumed there for a hundred or two of years. However, commercial production of tea in India did not begin until the arrival of the British East India Company, at which point large tracts of land were converted for mass tea production.
India was the top producer of tea for nearly a century, but was displaced by China as the top tea producer in the 21st century
Chemistry of tea
Caffeine the stimulant 3-4%, theobromine (.017%) and theophylline (.013%
Polyphenols – flavonoids, catechins Anittumor and antimutagenic Prevent tumor cell growth and division Green tea is 6 times better than black tea
Health effects
Tea leaves contain more than 700 chemicals, among which the compounds closely related to human health are flavanoides, amino acids, vitamins (C, E and K), caffeine and polysaccharides
associated with cell-mediated immune function of the human body
important role in improving beneficial intestinal microflora, as well as providing immunity against intestinal disorders
protecting cell membranes from oxidative damage.
prevents dental caries due to the presence of fluorine.
The role of tea is well established in normalizing blood pressure, lipid depressing activity, prevention of coronary heart diseases and diabetes by reducing the blood-glucose activity.
possesses germicidal and germistatic activities against various gram-positive and gram negativehuman pathogenic bacteria
Both green and black tea infusions contain a number of antioxidants, mainly catechins that have anti-carcinogenic, anti-mutagenic and anti-tumoric properties.
The IARC list teas as under Group 3 carcinogens since injection of black tea concentrates under the skins of mice showed some cancerous growths. However, it has not been possible to prove that tea affects humans in similar ways through consumption
COFFEE
This drink revives 1/3 of world’s population.
Coffee is a brewed drink prepared from roasted seeds, commonly called coffee beans, of the coffee plant. They are seeds of coffee cherries that grow on trees in over 70 countries. Green(unroasted) coffee is one of the most traded agricultural commodities in the world.[1] Due to its caffeine content, coffee can have a stimulating effect in humans.
http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GGIH,GGIH:2007-04,GGIH:en&q=picture+of+coffee+plant
The energizing effect of the coffee bean plant is thought to have been discovered in Yemen in Arabia and in the northeast region of Ethiopia, and the cultivation of coffee first expanded in the Arab world.
The plant
Coffea arabica (arabica coffee) – 75%, C. canephora (robusta coffee) 24% and C. liberica are grown commercially
Family - Rubiaceae Three varieties are known
Arabica Robusta Liberica
Coffee berries, which contain the coffee seed, or "bean", are produced by several species of small evergreen bush of the genus Coffea. The two most commonly grown are the highly regarded Coffea arabica, and the 'robusta' form of the hardier Coffea canephora. The latter is resistant to the devastating coffee leaf rust (Hemileia vastatrix). Both are cultivated primarily inLatin America, Southeast Asia, and Africa. Once ripe, coffee berries are picked, processed, and dried. The seeds are then roasted to varying degrees, depending on the desired flavor. They are then ground and brewed to create coffee. Coffee can be prepared and presented in a variety of ways.
Coffee Chemistry
Caffeine (1-2%) Chlorogenic acid Tannins (3-5%) Sugars (15-17%) Fatty oils (10 -15%) Proteins (10 -15%)
Caffeine Content
1 Cup of coffee – 65-175 mg
1 Cup of tea – 50 mg
Health and pharmacology
Most widely consumed neuroactive compound
Coffee prepared using paper filters removes oily components called diterpenes that are present in unfiltered coffee. Two types of diterpenes are present in coffee: kahweol and cafestol, both of which have been associated with increased risk of coronary heart disease via elevation of low-density lipoprotein (LDL) levels in blood
Aspects of Caffeine
Desirable effects
Stimulant, increased alertness, concentrate, energy, bronchial dilator
Toxicity
Restlessness, jitters, anxiety, insomnia, elevated or irregular heart rate
No tolerance
Most develop little or no tolerance to the nervous system effects
Withdrawal effects
Transient but persistent, headache, low energy, in ability to concentrate
Absorption
Rapidly absorbed following oral consumption
Peak blood (plasma) levels usually with 30 minutes
Distribution
Distributes into all body compartments –
Pass easily into brain, breast milk and crosses placenta
Does not accumulate
Metabolized in the liver
Changed to di- and mon- methylxanthines
Excreted in the urine
Metabolism/Elimination
How long it takes to leave the body
Average adult – 3-5 hrsChild less that 6 months – 24 hrsPregnant – 7-8 hrsSmoker – 2-3 hrs
Varies between individuals
Half-life
Blocks Adenosine receptor
Adenosine is a calming neurotransmitter
Mechanism Of Action
Adenosine ReceptorAdenosine Receptor
AdenosineAdenosine
Cell MembraneCell Membrane
Signal ProteinSignal Protein
Positive ResponseCalming effect
Positive ResponseCalming effect
Outside CellOutside Cell
Inside CellInside Cell
Adenosine binds to receptorAdenosine binds to receptor
11
33
22
Normal Action of Adenosine
CaffeineCaffeine11
Caffeineinactivates
receptor
Caffeineinactivates
receptor
No ResponseResulting in Stimulation
No ResponseResulting in Stimulation
3322
Action of Caffeine
Adenosine ReceptorAdenosine Receptor
Adenosinecan not bindAdenosinecan not bind
CaffeineCaffeine
1.Pleasant stimulant effects
2.Short Half-life (you need to back for more)
3.Can’t drink too much at any one time (toxicity)
4.Headache when you stop drinking it
Why so many $$s from caffeine?
Coffee consumption has been shown to have minimal or no impact, positive or negative, on cancer development;[75] however, researchers involved in an ongoing 22-year study by the Harvard School of Public Health state that "the overall balance of risks and benefits [of coffee consumption] are on the side of benefits."
coffee consumption reduces the risk of being affected by Alzheimer's disease, Parkinson's disease, heart disease,diabetes mellitus type 2, cirrhosis of the liver, and gout.
increases the risk of acid reflux and associated diseases
The presence of antioxidants in coffee has been shown to prevent free radicals from causing cell damage
In a healthy liver, caffeine is mostly broken down by the hepatic microsomal enzymatic system. The resulting metabolites are mostly paraxanthines-theobromine and theophylline-and a small amount of unchanged caffeine is excreted by urine. Therefore, the metabolism of caffeine depends on the state of this enzymatic system of the liver. Elderly individuals with a depleted enzymatic system do not tolerate coffee with caffeine.
both decaffeinated coffee and coffee with caffeine cause heartburn. Moderate amounts of coffee (50–100 mg of caffeine or 5–10 g of coffee powder a day) are well tolerated by most elderly people.
Coffee consumption can lead to iron deficiency anemia in mothers and infants. Coffee also interferes with the absorption of supplemental iron. Interference with iron absorption is due to the polyphenols present in coffee. Although the inhibition of iron absorption can cause an iron deficiency, iron is considered a carcinogen in relation to the liver. Polyphenols contained in coffee are therefore associated with decreasing the risk of liver cancer development
the smell of coffee can restore appetite and refresh olfactory receptors.
Over 1,000 chemicals have been reported in roasted coffee; more than half of those tested (19/28) are rodent carcinogens.[86] Coffee's negative health effects are often blamed on its caffeine content.
drinking caffeinated coffee can cause a temporary increase in the stiffening of arterial walls.[87] Caffeinated coffee is not recommended for everybody. It may aggravate preexisting conditions such as gastroesophageal reflux disease, migraines, arrhythmias, and cause sleep disturbances
Coffee is no longer thought to be a risk factor for coronary heart disease
may have a mixed effect on short-term memory, by improving it when the information to be recalled is related to the current train of thought but making it more difficult to recall unrelated information.
ability to act as an antidepressant. link between decrease in suicide rates
and coffee consumption, the action of caffeine in blocking the inhibitory effects ofadenosine on dopamine nerves in the brain reduced feelings of depression
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