This divine drink is tea
IntroductionWe love to drink tea: we drop in for tea with friends or in a cafe, drink tea for breakfast, lunch or dinner. “If you don’t drink tea, you can’t live in the world like that,” says folk proverb. But we don’t think at all about its benefits or harms,
what determines the quality and taste of tea, what is the difference between varieties and the difference in price, because today there are quite a lot of varieties of this product. Tea as a drink is so familiar and known to everyone that, it would seem, you won’t find anything unusual in it.
Relevance of the problem Tea
- Has a tonic effect on the human body
- Strengthens vital functions
- Perfectly quenches thirst
- Allows a person to endure the absence of food for a long time
- Is it true that tea has a tonic effect on the human body?
- Is it true that nature has created a kind of chemical warehouse of substances in the tea leaf?
- Identifying students' tea drinking preferences through a social survey.
- Study of the composition of tea and its effect on the human body;
- Comparison of types of tea by chemical properties;
- Research on tea as a natural indicator;
Unlike many other plants, the tea bush blooms in the fall. The ovaries overwinter on the bushes, and in the spring they begin to grow and develop; the seeds ripen in October.
The tea bush belongs to the tea family and is a perennial evergreen shrub. Withstands short-term frosts (up to –23°C) Tea shoots begin to develop at 11-12°C
Types of tea
The entire variety of teas is divided into four main types: black, green, red and yellow.
Color is only an external reflection of differences in biochemical processes processing of tea leaves, which ultimately affects the chemical composition and basic taste characteristics of each type of tea.
Getting black tea
- Withering (leaves become soft and curl)
- Fermentation (the chemical composition of the leaves changes significantly; the leaves acquire a copper-red color and a specific aroma)
- Drying (leaves turn black)
Drying (leaves retain their green color and natural properties)
Hibiscus tea
A floral tea drink obtained from the calyx of the flower of the hibiscus plant.
Chemical composition of tea Main components of tea
- Tannins consist of tannin and catechins, which give tea a pleasant astringency
- Alkaloids caffeine – increases vitality, invigorates theophylline – has vasodilating and diuretic effects
- Vitamins
- Tea leaves contain a large number of chemicals
- The tea leaf is a kind of chemical warehouse
The purpose of our work is to study chemical composition and properties of tea, research on tea as a natural indicator.
Method for determining caffeineReagents: magnesium oxide; concentrated nitric acid.
Equipment: porcelain cup, alcohol lamp, Petri dish.
Progress:
Pour 1 teaspoon of black into a porcelain cup loose leaf tea, added 0.5 teaspoon of magnesium oxide. We placed the cup on the tripod ring and covered it with a Petri dish. Light the alcohol lamp, heat the porcelain cup covered with the Petri dish in the upper part of the flame for 1-2 minutes
Method for determining caffeineThey removed the Petri dish. Add one drop of concentrated nitric acid to the caffeine. The appearance of an orange color indicates its presence.
Black tea
Reagents: iron (III) chloride.
Equipment: porcelain cups
Hibiscus tea
Method for determining tannin in teaTea "Riston" (black
bagged)
Ahmad black tea
bagged)
Method for determining tannin in teaTea "Riston" (black
sheet)
Ahmad black tea
sheet)
Method for determining tannin in teaTea "Riston" (green
bagged)
Ahmad green tea
bagged)
Change in color of Hibiscus tea (action of alkali) Change in color of black tea (action of alkali) Change in color of green tea (action of alkali) Change in color of black tea (action of acid) Change in color of green tea (action of acid)Vyacheslav Afanasyev, student of State Budgetary Educational Institution of Secondary Professional Education RO OATT, supervisor - M.I. Zadera, chemistry teacher
Presentation about the history of tea, its properties and benefits for the body
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Information project Tea The work was carried out by a first-year student of group VF-1-14 Afanasyev Vyacheslav GBOU SPO RO OATT
Tea is a drink obtained by boiling, brewing or infusing a leaf of a tea bush, which is previously prepared in a special way. Tea also refers to the leaf of the tea bush itself, processed and prepared for making a drink. This preparation includes preliminary drying (drying), rolling, more or less prolonged enzymatic oxidation, and final drying. Other operations are introduced into the process only for production individual species and varieties of tea.
Sometimes the word “tea” is also used as the name of a tea bush - a species of plant of the Camellia genus of the Tea family; In botanical scientific literature, the name Camellia sinensis is usually used for this species.
The raw material for making tea is the leaves of the tea bush, which are grown in large quantities on special plantations. Most tea plantations are located on mountain slopes in areas with a tropical or subtropical climate. Tea leaves are collected and sorted by hand: for teas of the highest grade (and value), unopened buds and the youngest leaves are used, only the first or second flush (the first or second group of leaves on the shoot, counting from the end); coarser teas are made from mature leaves.
By type of tea plant Chinese variety (Thea sinensis var. sinensis): Chinese (for example, Yunnan tea, oolong, etc.), Japanese (Sentya), Darjeeling, Formosan, Vietnamese, Indonesian, Georgian, etc., Assam variety (Thea sinensis var. assamica): Indian (Assamese, etc.), Ceylonese, Kenyan, Ugandan, etc., Cambodian variety, a natural hybrid of the above: grown in some areas of Indochina.
Origin: Chinese. China produces green and black teas; in addition, it the only country, producing white and yellow teas, as well as oolongs and puerhs. All Chinese tea produced from a Chinese variety of tea bush. Indian. The bulk of tea produced is black, produced from the Assam variety of the tea plant. Ceylonese. Manufacturer - Sri Lanka, share in world production - about 9-10%. Black and green tea are produced, only the Assam variety of the tea plant is cultivated. African. African teas are only black, cut, of medium and low quality, with good extract and a sharp taste. Turkish. Exclusively black tea, cut, for the most part medium or low quality, with poor extractivity, requiring boiling or soaking in a water bath to prepare the drink, rather than brewing. Russian. Krasnodar tea. It is produced in extremely small quantities and is practically never found on the market (even in Russia). Currently, this is the only type of tea that is grown directly in Russia.
According to the method of mechanical processing and type of tea leaf. According to the type of mechanical processing, teas are divided into three main groups: Long tea (loose); Pressed; Extracted (soluble). Baikhovo teas are the most common. This tea is a mass of individual, unrelated tea leaves. Pressed teas If the coarsest material is used for pressing brick tea - the lower leaves and even shoots of tea bushes, then for pressing slab and tablet tea - tea crumbs and powder formed during the production of long teas. Extracted Teas As for extracted teas, they are produced either in the form of a liquid extract or in a dry, crystalline form (powder from one way or another dehydrated brewed tea), they are given the general name of instant teas. Its weak bouquet is usually made up for by aromatization.
By additives There are many varieties of flavored tea and tea with additives - floral, fruit and others. The aroma can be imparted to tea by the direct addition of flowers, dried berries or fruits, the addition of natural or artificial essential oils, as well as keeping the tea in contact with aromatic additives (they are separated from the tea with paper or cloth, but transfer their aroma to it, since the tea easily absorbs foreign odors). The most common varieties of flavored tea are: “Earl Grey” (English Earl Grey) with the aroma of bergamot, jasmine tea with jasmine flowers, genmaitha - tea with fried rice, popular in Japan, tea with the aroma of lemon, known in the West as “Russian tea” , Tuareg mint tea. In addition to the above, lotus flowers, peony, roses (or rose oil, or its substitute), cherries, orange zest, strawberries, artificial flavors with the smell of cream, chocolate are often used to flavor tea.
Usage The tea drink is prepared primarily by brewing: dry tea is poured hot water and infuses for some time. The dosage of dry tea, infusion time and water temperature depend on the type of tea and tradition. In most traditions, it is believed that the higher the degree of fermentation of tea, the higher the temperature of the water. In any tradition, preparing and drinking tea usually includes the following steps: general preparation for tea drinking, measuring and preparing the tea leaves, heating the water, preparing dishes for brewing, brewing, pouring the tea, and actually drinking the tea.
Effect of tea The tea drink is a complex combination of substances that has a multifaceted and generally beneficial effect on the human body. The total number of chemical compounds included in its composition, isolated at the end of the 20th century, is about 300, some of them have not yet been identified, and the biochemical role of some of the known ones is defined only in general terms. Characteristic groups of substances present in tea: Tannins, in particular tannin, which is responsible for the characteristic tart taste of tea. Essential oils that impart aroma to tea and affect its taste. Alkaloids, primarily theine (tea caffeine), due to which tea affects nervous system. Proteins and amino acids that affect metabolism. Biological pigments responsible for the color of tea (thearubigens, theaflavins, carotene, chlorophyll, xanthophyll).
Changes in properties when milk is added Various independent studies claim that when milk is added to tea, it loses a number of beneficial properties. In particular, the positive effect on the cardiovascular system disappears, and the anticancer effect decreases due to a decrease in the level of antioxidants.
In medicine The strong bactericidal effect of tea has been confirmed experimentally. Recipes for using tea in the form of dry powder, leaves, extract or infusion for medical purposes have long been known, including for treating ulcers, burns, washing festering eyes, and stopping vomiting. The modern pharmaceutical industry produces caffeine from tea (including tea production waste), and from coarse lower leaves- vitamin P. Vitamin P preparations are used, in particular, in the treatment of internal hemorrhages and radiation sickness. Tea extracts are used as a sedative and analgesic, in some cases replacing morphine
In the food and cosmetic industries, methods have been developed for producing yellow, green and brown food dyes from tea. These dyes are used in confectionery industry(in particular for coloring marmalade and dragees), their advantage is that they are absolutely natural and harmless to humans; moreover, tea food coloring contains vitamin P. In cosmetics, tea can also be used as a dye, for example, in hair dyes.
Myths and legends associated with tea According to Chinese tradition, tea was discovered by the cultural hero Shen-nong, the patron of agriculture and medicine, one of the Three Great Ones, who created all crafts and arts. According to legend, Emperor Shen Nong traveled in search of medicinal herbs with a cauldron on a tripod in which he boiled water for healing decoctions. In 2737 BC. e. Several tea tree leaves fell into a cauldron of boiling water. The broth seemed tasty and gave me energy. Since then, Shen-nong has not drunk any other drinks. Another myth, of more recent origin, attributes the invention of tea to the famous Buddhist preacher, founder of Chan Buddhism, Bodhidharma. According to legend, in 519 AD. e. Bodhidharma was meditating, but fell asleep. Waking up, in anger, he pulled out his eyelashes (or cut off his eyelids) and threw them to the ground. The next day, tea tree seedlings grew in this place. Bodhidharma tried a decoction of the leaves and found that they drove away sleep.
The work was carried out by KSENTYA WAYMAN, a student of the % class of Municipal Educational Institution Secondary School No. 45 in Tver.
Presentation on cooking - topic hot drinks "Tea" for 5th grade students. The work was carried out by Ksenia Vaiman. The presentation provides a complete understanding of the types of tea and how to use it. The work was done competently and can be used not only by students to improve their knowledge, but also by teachers when conducting technology lessons.
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Tea The work was completed by a 5th grade student of Municipal Educational Institution Secondary School No. 45 of the city of Tver Vaiman Ksenia
What is tea? Tea is a drink obtained by boiling, brewing, or infusing a leaf of a tea bush, which is previously prepared in a special way. Tea also refers to the leaf of the tea bush itself, processed and prepared for making a drink. Tea bush branch
Growing and harvesting tea The raw material for making tea is the leaves of the tea bush, which are grown in large quantities on special plantations. In China, India and Africa, where the largest share of tea is produced, harvesting takes place up to four times a year. The most prized teas come from the first two harvests.
Growing and Harvesting Tea Tea leaves are collected and sorted by hand: for teas of the highest grade (and value), unopened buds and the youngest leaves are used. The work of the pickers is quite hard and monotonous: the ratio of the mass of finished black tea to the raw leaf is about ¼, that is, to produce a kilogram of tea it is necessary to collect four kilograms of leaf. The production rate for pickers is 30-35 kg of sheets per day.
Types of tea; Baikhovye (loose) Baikhovye teas are the most common. This tea is a mass of individual, unrelated tea leaves. Black long teas are divided according to the size of the tea leaves into: leaf (large); broken or broken (medium); seeding and crumbs (small).
Types of tea Pressed teas Among pressed teas there are: brick; tile and tablet.
Types of Tea Extracted Teas When it comes to extracted teas, they are produced either in the form of a liquid extract or in a dry, crystalline form, and are given the general name of instant teas. Its weak bouquet is usually made up for by aromatization. Attempts to prepare tea concentrates in the form of a highly soluble extract that does not require a brewing procedure have been made for a long time. Modern instant teas are prepared either by directly processing tea leaves and extracting juice from them, or from an infusion of highly concentrated tea. They are not particularly different from tea brewed from dry leaves. Its positive property is the simplicity and speed of preparation.
Types of tea Granulated tea Tea in bags Bagged tea consists of tea crumbs and dust, or very fine long tea, placed in bags made of filter paper (in the past, fabric was also used as a material for bags, now a fine polymer mesh is also sometimes used).
Types of tea Capsule tea Since the advent capsule coffee machines a technology for quickly brewing tea has appeared: tea is passed through a special capsule placed in a special capsule hot water under pressure. On this moment Capsule tea is not particularly diverse and is not very widespread, however, some versions of tea in capsules are already presented by several companies.
Types of tea There are many varieties of flavored tea and tea with additives - floral, fruit and others. The aroma can be imparted to tea by the direct addition of flowers, dried berries or fruits, the addition of natural or artificial essential oils, as well as keeping the tea in contact with aromatic additives (they are separated from the tea with paper or cloth, but transfer their aroma to it, since the tea easily absorbs foreign odors).
Types of tea Herbal teas There is a large group of drinks - herbal, berry, flower infusions, brewed leaves of other trees and shrubs, which are traditionally called teas, although they do not contain actual tea tree leaves: Chamomile tea Rosehip tea Currant tea Thyme tea St. John's wort tea Oregano tea ...
Consumption The tea drink is prepared primarily by brewing: dry tea is poured with hot water and infused for some time. The dosage of dry tea, infusion time and water temperature depend on the type of tea and tradition. In any tradition, preparing and drinking tea usually includes the following steps: general preparation for tea drinking, measuring and preparing the tea leaves, heating the water, preparing dishes for brewing, brewing, pouring the tea, and actually drinking the tea.
Other ways to use tea In medicine Recipes for using tea in the form of dry powder, leaves, extract or infusion for medicinal purposes have long been known. In cooking, powdered dry tea is used as a seasoning for a wide variety of dishes. Fresh tea leaves, eaten raw, are eaten as a salad. Tea extract from fresh green leaves is used for preserving food products, including meat, like good remedy, preventing rotting and deterioration. In the food and cosmetic industries, methods have been developed for producing yellow, green and brown food dyes from tea. In cosmetics, tea can also be used as a dye, for example, in hair dyes. Other Uses Tea oil is produced from the seeds of the tea plant. In composition and properties it is close to olive oil, especially cold-pressed oil. Used in various industries.
Slide 1
HISTORY OF TEA Where and when did tea come to us? What beneficial properties does he have? Extracurricular activity in the 6th grade of the municipal educational institution “Secondary school No. 27 with in-depth study of individual subjects” in the city of Balakovo, Saratov regionSlide 2
One day, 5 thousand years ago, a Chinese emperor, while relaxing in the forest, ordered water to be warmed for drinking. Suddenly the wind rose and several tea leaves fell into the cup. The Emperor drank the drink and felt more cheerful.
Slide 3
Tea is a Chinese word. It appeared where Russian people traded with the Chinese of the northern provinces; they call tea cha-e, hence our word tea
Slide 4
One Englishman managed not only to steal tea seeds, but also to learn the secret of its complex processing. Thanks to this, Europeans were able to grow tea in their colonies
Slide 5
In Russia, the first tea party took place in 1638. The Tsar's steward V. Tyumenets, being an ambassador to Mongolia, first tried the drink at the feast, which he liked, and Altynkhan sent the Russian Tsar Mikhail Fedorovich several pounds of tea. In Russia, tea has become widespread, especially in the northern and eastern regions of Siberia and Central Asia.
Slide 6
The tsar and his boyars initially used the drink as a medicine for illness and bodily fatigue. After all, doctors attributed to him the ability to “refresh and cleanse the blood” and the ability to keep him from sleeping during church services. They liked the tea so much that they became addicted to drinking it at the royal court and in the boyars' mansions every day.
Slide 7
Soon Russia took second place after England in tea consumption. Specialized shops selling tea were opened in large cities of the country. True, for a long time this drink was considered rare and belonged to the nobility. Tea drinking in Russia has become so popular over 300 years that it has become one of the national customs. One of the foreign travelers noticed that the Russians had practiced making tea so much that they unexpectedly invented a samovar. They appeared in Russia in 1679.
Necessary conditions for good tea: 1. Good tea and quality water. 2. Convenient dishes that do not contain foreign odors. 3. White key water. 4. Warmed up teapot. 5. Correct water temperature. 6. It is important not to over-bake the tea.
To get true pleasure and maximum benefits from tea, you need to store, prepare and drink it correctly. At long-term storage tea essential oils evaporate and it loses its aroma. Tea easily absorbs moisture and is susceptible to various odors. Therefore, it should be stored in porcelain, earthenware or glassware with the lid tightly closed.
Brew tea only in a porcelain or earthenware teapot, having first poured boiling water over it. After pouring in the tea leaves, pour boiling water and cover the kettle with a towel or napkin so that the lid and spout of the kettle are closed to preserve the aroma. You can’t cover it with a hot-water bottle doll: the tea must simmer, otherwise it will smell like a broom. Some people pour boiling water to 1/3, to ?, to 2/3, others immediately to the top, leaving 1-1.5 cm unfilled to the lid (a place for foam to form).
Infuse black tea for 5 minutes and green tea for 8 minutes. For brewing, the water must be clean and soft. The ideal source of water for tea are springs, streams, and mountain rivers.