Chapter 1

·      The cultivars which show better fermentability and higher content of polyphenols are evaluated to be a good quality for black tea manufacture

·      Almost all of the cultivars belonging to the var. sinensis group have a relatively low fermentability and less content of polyphenols.

·      The “ferment ability” of tea leaves is genetically regulated as shown by the activity of polyphenol oxidase which is controlled by a polygene system and shows high value.

·      The genetic trait has been taken as one of the main marks in the breeding program of tea, especially of black tea.

·      In three to four years after tea tree cuttings which were rooted on the nursery field and later transplanted to the farm, the young plants are pruned and arranged into a semi cylindrical shape to be convenient for field work.

·      Young buds and leaves for 5-6 year old trees are nipped three to four times a year

·      The steaming treatment protects against degradation of vitamins and thus the content of green tea is much higher than fermented teas

·      Then dried in a current of air of moderate temp

·      The moisture content of the fresh leaves that is usually 78-80% decreases to about 10$ during the rolling process

·      The rolling process disrupts the leaf tissue and mizes them uniformily in shape as much as possible

·      The rolled and dried leaves called aracha are finally roasted and cut to prepare the final products by tea dealers the firing also adds a fired flavor.

·      Shading of the tea plant increases the amount of amino acids, especially of theanine in young shoots and decreases the polyphenol content.

·      High correlation between the price of tea and content of amino acids especially of theanine or arginine

·     

·      Cha-no-yu

·      The tea ceremony where matcha is consumed

·      78.6% is processed to produce Sencha

·      12% Bancha

·      0.4 Gyokuro

·      0.6% Matcha

The tea leaf is rich in polyphenols and the amount is more than 10% on a dry basis. It is also rich in caffeine amounting to 1-4% of the dried leaf. The content of amino acids especially those of theanine and glutamic acid are relatively high. These chemical components have various physiological functions, which will be described.

1.     Carbohydrates including cellulosic fiber

2.     Protein, these components are almost insoluble

3.     Tea polyphenols

4.     Caffeine

5.     Vitamins

6.     Inorganic Elements

7.     Lipids

·      Polyphenols are almost infused with hot water or exracted with ethyl acetate form the aqueous solution. The slight astringent and bitter taste of green tea infusion is attributed to the polyphenols.

·      Six kind of catechin and its derivatives which slightly deviate depending on the species of tea plant and season 14of harvesting

·      (+)-GC and )+)-C are usually trace or minor component

·      -Epigallocatechin and epigallocatechin gallate are stronger in bitterness and more astringent than epicatechin or epicallocatechin

·      Catechin is synthesized in tea leaves through malonic acid and shikimic acid-metabolic pathways.

·      Gallic acid is derived form an intermediary product produced in the shikimic acid-metabolic pathway

·      Caffeine has been found to be a cardiac stimulant and a diuretic. It also stimulates the cerebral cortex to induce excitation in the central nervous system.

·      It can cause irritation of the gastrointestinal tract and sleeplessness

·      Other nitrogenous compounds in the tea infusion are amino acids,amides, proteins, and nucleic acids.

·      Theanine and glutamic acid are the major amino acids in the green tea infusion and aspartic acid and arginine are the next.

·      The contents of amino acids in tea leaves harvested in spring are larger than those in later seasons.

·      Theanine in tea leaves is a unique amino acid and is known to be produced by the tea plant and certain species of genus Camellia.

·      The rate of metabolism of theanine in tea leaves in slow but its transport from root to leaf is so rapid that this amino acid is accumulated in tea leaves

·      Chemical and biochemical characteristics of theanine are described in ch.12–àsee notes from CH 12

·      Vitamin C content of oolong or black tea is less than green tea because it is decomposed during the enzymatic process.

·      The levels of aluminum and fluorine are relatively higher than other plants. Tea plant is scarcely affected even in the field containing large amounts of aluminum sulfate which is a main causal factor for acidic soil.

·      It has been presumed that the tea plant has a biochemical mechanism to neutralize the toxicity of aluminum

·      In the leaf aluminum exists mainly in a chelate form, indicating that Catechins prevent the expression of damage by accumulation of aluminum.

·      starch is also contained and affects the quality of green tea

·      the synthesis of starch begins with dawn and ends at sunset, therefore, the content of starch in the tea leaves varies significantly in the day.

·      Starch in tea leaves harvested in the morning is less than that in the afternoon.

·      The tea leaves harvested in the morning are usually evaluated to be better quality

·

·      Polyphenols are produced as a secondary metabolite of higher plants

·      Plant polyphenols can be divided into two major groups

1.     Proanthocyanidins

2.     Polyesters based on gallic acid and or hexahydroxydiphenic acid as their derivatives.

In chemistry , a derivative is a compound  that is derived from a similar compound by a chemical reaction.

·       Green tea polyphenols are a class of flavanols which are C15 compounds and their derivatives are composed of two phenolic nuclei A and B ring, connected by three carbon units C-2, C-3, C-4

·       The flavanol structure of catechin (3,3’4’,5,7-pentahydroxyflavan contains two asymmetric carbon atoms at C-2 and C-3

·       Catechin and its derivatives also have nucleophilic centers at C-6 and C-8

·       Which are reactive with electrophilic specimens. They are highly chemically reactive showing the properties of metal chelator, oxidative radicals scavenger, nitrosation in habitor

Chapter 1

Editor –in-chief, American Journal of Clinical Nutrition, Associate in Medicine, Indiana University, Medical School.

Introduction

·      “Five recognized authorities present the known pertinent facts about the pharmacologic, physiologic, psychological, and clinical aspects of tea. Yet, as these presentations show, tea is more than an aqueous infusion of caffeine and tannins: it has effects beyond what can be seen by the gastroscope, or deducted from gastric aspiration; one cannot describe its ancient popularity on the basis of its somewhat negligible vitamin and mineral content. Some how the vital fraction remains undiscovered-or perhaps there is no single missing factor, but merely the fortuitous combination of fractions, which together produce something bigger and better than the simple addition of components.”

·      “At least some similar explanation must be devised to explain the fact that tea as a beverage has been known from earliest times. It was perhaps the first drink made by man for the express purpose of enjoying whatever mysterious qualities it has. Let us not forget that in past millenniums man did not have a shiny aluminum tea kettle, electric range and neatly packaged, standardized tea leaves. It must have been quite a chore to rustle up a cup of tea in ancient Cathay.

·      Tea is a loved drink across Europe, The United States, etc.

·      Much of the stimulus to the 16^tha and 17^th century exploration was derived from large commercial ventures as the English and Dutch East India Companies.

·      The golden age of the China Clipper ships in the mid 19^th century was due to the tea trade for these were tea carrying cargo vessels

·      “Tea for Two” in song

·      “Tea and Sympathy”
·      “The Tea House of the August Moon”

·      The reading of tea leaves by fortune-tellers

·      Tea and toast as a sensible home remedy for many ills

·      Standard household management, the teaspoon

·      2700 BC

·      “Built a fire from the branches of a the plant. Some of the leaves accidently fell into the boiling water. The exhilarating effect of this accidental brew led him to popularize the custom.”

·      The most important constituents of tea are the mixed xanthine bases

·      The principal one of these is trimethyl xanthine which, has been found to identical with caffeine

·      Theobromine, theophylline, and Xanthine

1.     Cerebral stimulants

2.     Coronary vessel dilators

3.     Diuretics

·      Other actions inclue cardiac stimulation and respiration stimulation.

·      Of the three main actions of the methylated xanthines, caffeine is preferred for cerebral stimulation

·      Theophyline is the drug of choice for coronary dilation

·      Theophylline exceeds theobromine in its acute diuretic action but the diuresis of theobromine is more prolonged and therefore is the iduretic which is generally prefered.

·      Thiamine B-vitamin 1

·      7-25% in the dried leaf

·      Tannins designated as the polyphenols

·      The tannins or polyphenols may be divided into two classes depending upon their solubility in ethyl acetate.

·      Soluable group occurs as an orange powder

·      The insoluable group as a born powder

·      Odorless and elicits a bitter taste

·      The principal site of action of caffeine is on the central nervous system and the sensory cortex

·      Larger doses affect the motor areas and the action descends to the medulla oblongata and the spinal chord

1.     Increased mental alacrity

2.     Altertness and brighter spirits

3.     More acute and discriminating sensations

4.     Facilitation of association of ideas

5.     Retardation of action owing to more discriminating judgement

6.     Occasional insomnia

·      Therapeutic use in hypertensive headaches

·      Shown to decrease the arterial and post-arteriolar vascular tension of cerebral vessels, and through this mechanism relieves hypertensive headaches

·      Caffeine affect on the respiratory system, and blood pressure were mostly when the caffeine was administered other than orally.

“Actually, in one sense, we need no experimental proof of the psychological benefits of tea; in many cases it is sufficient for the physician’s purposes that his patient merely think that tea has cheered and brightened his attitude toward life. If there is a distinction between one who is happy and one who thinks he is happy, the distinction is semantic”

·      “Nevertheless, there is satisfaction to be gained from the fact that experimental proof does exist”

·      One explanation of the paradox is that caffeine and tea tannins interact antagonistically when they meet in a cup of tea

·      Thus the gastrointestinal disturbances ordinarily induced by each separately are counteracted and the two substances form an antagonistic synergism.

·      Vitamin C

·      Halpenny and MacDermot study

·      Investigated the separate affects of tea, coffee, caffeine, and tannin in terms of clinical effects, gastric analyses, peptic activity in vitro, metabolic rate changes, gastroscopic observation, barium meal examinations.

·      Look into study

·      The difference in constituent proportions between types of tea appears to be significant only in fluorine content. This varies not only with plant variety but also with the age of the plant: the older the plant, the higher the amount of fluorine. Oxidation has it’s effects: the highest fluorine content is in black tea, there is less in semi-oxidized Oolong and lest in green tea.

·      Many of the substances are in trace amounts much of the pharmacology is due to the caffeine and the balance between the caffeine and tannins.

·      The balance together does not produce the ill effects that can be experienced when consumed separately.

·      Another variable that can affect the tea is the length of brewing and the quality. Since the type of tea, length of the brew, and the temperature of the water will change the amount of tannins and caffeine the brew will change in balance depending on the skill of the tea maker.

·      Three minutes after pouring boiling water on tea most of the caffeine has been extracted and the caffeine/tannin ratio is at its highest.

·      A longer brewing adds progressively more tannin but little or no additional caffeine

·      Less research done around tannins.

Budhidharma

6^th century Indian Prince

founder of chan Buddhism, which would become zen buddhism

·      Tea is a beverage to be tasted and enjoyed for its delicate aroma not to be gulped or poured down the gullet for effect with as little contact with the tongue as possible.

·      Tea drinking encourages a sensitive and discriminating enjoyment of intellectual and social exchange.

·      American custom of iced tea on a summer afternoon

·      The art of being relaxed while fully conscious

·      They contribute to the enjoyable experience of finding oneself socially accepted by people who are quite sober.

·      It encourages courteous and lively discussion in an atmosphere of mutual respect.

Chapter 1

·      “pekoe” is from the Chinese pak-ho often used to describe the fine down on a newborn’s skin.

·      Pekoe is a reference for the three types of tea-leaf picking: imperial picking, fine picking, and medium picking.

1.     Imperial Picking: the bud and first leaf below it.

2.     Fine Picking: the bud and the first two leaves

3.     Medium Picking: the bud and the following three leaves

2.     Bi Luo Chun

3.     Anji Bai Cha

4.     Xin Yang Mao Jian

·      Represent 70% of all Chinese production

·      Major growing regions are located in the south of the country

1.     Fujian

2.     Zhejiang

3.     Anhui

4.     Henan

5.     Jiangsu

6.     Jiangxi

·      The traditional method is to spread the leaves on bamboo racks and leave them to dry for one to three hours in order to remove the surplus water.

·      To prevent them from drying too rapidly they are sometimes spread on cloths in the shade

·      The mechanical method involves spreading the leaves in cylindrical machine with bamboo walls so that they spin dry for a few minutes while fans blow air on them

·      The enzyme polyphenol oxidase is triggered to breakdown the leaves cell structure when the leaves have been picked, withered, and rolled. To half this process of oxidation the leaves are dehydrated.

·      Methods vary according to region

·      Small quantities of leaves are put in pans or vats that are consistently stirred so they don’t burn.

·      Next different techniques are used according to the form the leaves are supposed to take. If the leaves are to be flat, as in the long Jing variety they are pressed to the bottom of the vat briefly before being stirred in a back and forth movement.

·      If it is to be curly like the Bi Luo Chun variety they are rolled by hand and constantly stirred until they dry.

·      The heat starts low and then gets higher in the vat. The temperature will vary depending on conditions.

·      When the leaves are mechanically pressed they are heated at least three times in rotating cylinders.

·      Sometimes in between heating periods they will be spread on cooling cloths.

·      As the leaves are heated a chemical process is triggered: The sugars and proteins they contain are transformed giving the tea an aromatic quality that is sometimes reminiscent of grilled nuts.

·      Shaped by hand or machine into twisted, flat, needle shaped, or bead shaped leaves.

During this stage the aromatic oils released during rolling become stabilized in the leaves. Any remaining water is eliminated to remove any risk of mold. At the end of this process only 2-4 percent of moisture remains in the leaves.

·      The leaves are then sorted by size by means of a bamboo mesh of different sizes placed one on top of another.

·      Monks used tea as a stimulant to stay awake during long hours of meditation

·      Monk Saisho, is said to be the first to bring the custom to Japan.

·      There was strained relationship between China and Japan at the time though and it was not until the end of the 12^th century that Japan could truly be considered as having a tea culture.

·      1191 monk Eisai (1141-1215) founder of the Rinzai sect of Zen Buddhism brought a few tea-tree seeds back from a pilgrimage to China and planted them in the Hizen, in the Northern part of the island of Kyushu, as well as around the monasteries of Hakata (Fukuoka).

·      Eisai spread the idea that tea should be consumed for its medicinal properties.

·      Eisai wrote the first Japanese book on tea. Published in 1211.

·      He brought plants as well as introduced the Japanese to the Chinese method of preparing tea used during the Song dynasty (960-1279)

·      Tea leaves were ground to a fine powder before being brewed.

·      The ritual and discipline as well as the austere nature of Rinzai Zen philosophy had a great influence on the rigidly codified evolution of the Japanese Tea ceremony

·      Later, tea plants were planted on the main island of Honshu near Kyoto, the former capital of Japan.

·      Originally cultivated by Monks

·      13^th century, noblemen were meeting to drink tea during ceremonial gatherings, the samarai also made it party of their lifestyle.

·      16^th century, grand tea masters appeared, one being Sen no Rikyu. He codified the tea ceremony (chanoyu) and established a close relationship between Buddhist values and the various schools of Japanese tea of the era.

·      1641-1853, Japan remained cut off from the rest of the world. It was a policy of isolation, known as sakoku. It forbade anyone from leaving the archipelago and permitted almost no contact with the outside world.

·      For more than 200 years china alone provided the rest of the world with tea.

·      Isolation had some positive notes.

·      1738, Soen Nagatani created a method of leaf dehydration using steam. Thanks to this method, the fresh aroma of the leaves creates a green tea that is very different from Chinese green tea.

·      1859, Japan abandons policy of isolation and opens to the international market and began to export teas.

·      End of the 19^th century the archipelago began industrializing its production methods in particular with the use of heating cylinders invented by Kenzo Takahashi. Around this time the Japanese began to produce black tea.

·      First years after the first world war Japanese tea exports set an unprecedented records; they exported up to 22,003 tons of green tea.

·      The explosion in demand was short lived and Japanese exports of black tea dropped quickly

·      Japan had a hard time competing with the tea coming out of Sri Lanka, India, and Kenya.

·      In 1920s studies on tea Catechins were released to the public to promote the sale of tea and to encourage citizens to consume it on a daily basis.

·      Mixture of leaves and roasted and popped grains of rice. It was originally a beverage drunk by the poor who supplemented their tea with rice.

·      Usually made with Bancha but can also be made of Sencha and Matcha teas

·

Bancha Shizuoka

·      An everyday tea up until the middle of the Edo era (1603-1868) for rural regions every household once grew a small amount for personal consumption.

·      Large pieces of irregularly shaped leaves make up the June harvested Bancha tea.

Sencha

·      There are two major styles of Sencha tea: Asamushi and Fukamusi.

·      Asamushi has a shorted dehydration period and rigoriously sorted leaves.

·      Fukamusi has a longer period of dehydration and more fine particles preserved through storage

Kabusecha Banryu

·      Shade grown tea cultivated in gardens that are covered by canopies for about two weeks before the leaves are picked. The goal is to increase the level of chlorophyll and amino acids (particularly theanine) in the leaves.

Matcha

·      Intoduced by Buddhist monks at the beginning of the first millennium, Matcha was the first type of tea consumed in Japan. Originally dried up and ground between millstone.

·      Some modern taste lends the Matcha to be aged for a few months after processing

·      Sencha Keikoku (Sencha means infused tea)

·      Hojicha Shizuoka (Hojicha menas leaves that have been roasted for a few minutes at temperatures of 390 degrees F)

·      Bocha

·      Kamairicha