Module 8. Tea
Lesson 28
TEA-INTRODUCTION AND CLASSIFICATION
28.1 Introduction
Tea is one of the most popular beverages in the world. It also provides valuable source of income to many tea producer countries. It is a capital earning industry. To promote its development, the Govt. of India has set up Tea Board under the Ministry of Commerce. Tea Taster’s academy has recently come up in Coonoor in the Nilgiris.
Tea is a perennial plant having a lifespan extending 100 years.
The popularity of tea is due to:
28.2 History
The history of tea production in India spans more than 160 years. In 1838, the first consignment of tea from Assam was shipped to England.
The word ‘Chai’ is derived from a Cantonese word ‘Chah’. Plantations in Darjeeling, Tarai and Dooars regions of northern Bengal and Nilgiris and other regions of South India.
28.3 Origin and Distribution
Centre of origin – Southeast China
Later it spread to Southern portion of China, parts of India, Myanmar, Thailand, Laos and Vietnam
Early part of 19th Century – An unsuccessful attempt was made to establish Chinese tea in India. Only when the native ‘wild’ tea plants found in Assam were used, the tea production in India became successful.
Tea industries in India are there in Assam, West Bengal, Kerala, Karnataka, Tamilnadu and to some extent in Tripura and Himachal Pradesh.
28.4 FSSA Definition of Tea
Tea means tea other than Kangra tea obtained by acceptable processes, exclusively from the leaves, buds and tender stems of plant of the Camellia sinensis (L) O. Kuntze. It may be in the form of black or oolong tea. The product shall have characteristic flavour free from any off odour, taint and mustiness. It shall be free from living insects, moulds, dead insects, insect fragments and rodent contamination. The product shall be free from extraneous matter, added colouring matter and harmful substances.
Tea may contain ‘natural flavours’ and ‘natural flavouring substances’ which are flavour preparations and single substance respectively, acceptable for human consumption, obtained exclusively by physical processes from materials of plant origin either in their natural state or after processing for human consumption in packaged tea only. Tea containing added flavour shall bear proper label declaration. Tea used in the manufacture of flavoured tea shall conform to the standards of tea. The flavoured tea manufacturers shall register themselves with the Tea Board before marketing flavoured tea. The product shall conform to the following requirements expressed on basis of material oven-dried at 103±2oC. The specifications for tea are furnished in Table 28.1.
Table 28.1 Specific requirements of tea by FSSA
|
Parameters |
Requirements |
|
Total ash (w/w) |
Min. 4.0% and Max. 8.0% |
|
Water soluble ash |
Min. 45% of total ash |
|
Alkalinity of water soluble ash expressed as KOH (w/w) |
Min. 1.0% and Max. 3.0% |
|
Acid insoluble ash (w/w) |
Max. 1.0% |
|
Water extract (w/w) |
Min. 32.0% |
|
Crude fibre (w/w) |
Max. 16.5% |
28.4.1 Kangra tea
It is derived exclusively from leaves, buds and stems of plants of the Camellia sinensis grown in Kangra and Mandi valleys of Himachal Pradesh.
Tea for domestic market may contain added vanillin flavour up to a maximum extent of 0.5% by weight and other flavours as depicted in Table 28.2.
Table 28.2 Permitted flavors for inclusion in tea by FSSA
|
Flavours |
Per cent by weight (Max.) |
|
Cardamom |
2.8 |
|
Ginger |
1.0 |
|
Bergamot |
2.0 |
|
Lemon |
1.6 |
|
Cinnamon |
2.0 |
|
Mixture of above flavours |
The level of each individual flavour shall not exceed the quantity specified above |
28.4.2 Green tea
It means the product derived solely and exclusively, and produced by acceptable processes, notably enzyme inactivation, rolling or comminution and drying, from the leaves, buds and tender stems of varieties of the species Camellia sinensis (L) O. Kuntze, known to be suitable for making tea for consumption as a beverage. The product shall have characteristic flavour free from any off odour, and rodent contamination visible to the naked eye. The product shall be free from extraneous matter, added colouring matter and harmful substances. The other specifications for such tea are same as for Tea, except for total catechins which should be min. 9.0 and max. 19.0% w/w.
28.5 Health Benefits of Tea
Black tea leaf contains significant amounts of vitamin E & K. Vitamin C is present in green tea, but only traces are found in black tea. The phenolic constituents (referred to as vitamin P) strengthen the walls of capillary blood vessels. Tea also contains vitamin A (carotenoids) and vitamin B. It is too low in Fe, Cu and Fluoride.
5 cups of tea supplies 25% and 10% of the daily requirements of minerals like Mn and Zn respectively.
Catechins (viz., epigallocatechin gallate) have antimicrobial and anticancer properties. The black tea polyphenols absorb metals from the diet i.e. lead from contaminated water. Moderate amount of caffeine present in a cup of tea is mildly stimulating whilst provoking minimal irritability.
Decaffeinated teas have already appeared in the market.
28.6 Adulteration
Common adulterant is ‘spent’ or ‘used’ tea plus some colouring substances unfit for human consumption.
28.7 Health Hazards
Caffeine is toxic to cardiovascular and nervous systems, when consumed excessively. Tea contains tannin which interferes with Fe absorption. Thus, it is prudent to avoid tea either before or after meals.
28.8 Caffeine in Tea
It is an important pharmacological agent.
Mild stimulating action – central nervous system is almost indiscriminately stimulated from the top downwards; helps enhancing work efficiency by overcoming fatigue.
Caffeine often prescribed for migraine headache. It induces secretion of catecholamines in mammalian tissue.
Increases the level of serum lipids, but this effect is almost nullified by antilipidemic activity of high levels of polyphenols in tea. It is effective as a respiratory stimulant; produces peripheral vasodilation and increased circulation in kidneys and brain; increases the number of active glomeruli in the kidney and has a diuretic action.
Caffeine causes secretion of both acid and pepsin in the stomach and can aggravate peptic ulcer.
28.9 Classification of Teas
Tea plant Camellia sinensis (L) O. Kuntze is the only important economic species of the family Theaceae.
The two botanical varieties are recognized
28.9.1 China tea (Camellia sinensis var. sinensis)
It is a variety found in more temperatate producing regions such as China, Japan, USSR< Turkey, Iran and Northern, higher altitude growing areas of India. It produces delicately flavoured tea.
28.9.2 Assam tea (Camellia sinensis var. assamica)
It can survive only at high altitudes near the Equator. It is less resistant to cold than China type and much higher yielding plant, but produces less delicately flavoured beverage.
28.9.3 Hybrids
Hybrid between China and Assam types e.g. Darjeeling tea.
The desired aroma is produced during cool, clear, dry windy weather with day and night temperatures of 20oC and 6-10oC respectively.
It is referred to in relation to place where it is grown
India – Assam Tea, Darjeeling Tea, Nilgiris Tea
Sri lanka – Orange pekoe Tea
China – Lapsang Tea, Sonchong Tea, Earl grey Tea.
28.10 Types of Processed Tea
28.10.1 Fermented or black tea
They contribute a major proportion of tea consumed in Western hemisphere. They are produced by full fermentation and roughly classified as ‘Plain’ or ‘Flavoury’.
28.10.2 Plain black tea
The taste characteristics are associated with the phenolic substances produced during fermentation e.g. Assam tea.
28.10.3 Flavoury black tea
They are sold on the basis of their aroma characteristics e.g. Darjeeling tea.
28.10.4 Green tea
There is no fermentation; the leaf remains green. When infused, the liquors are greenish, pale primrose or lemon-yellow in colour with no trace of red or brown. They are produced and consumed mainly in China and Japan. Green tea constitutes ~ 20% of total production.
28.10.5 Partially fermented tea
These are partially oxidized so that their appearance is somewhat intermediate between that of green and black tea. They are manufactured primarily in China e.g. Oolong, Pouchong teas.
Oolong or Ponchong or Red Tea forms only 2% of total tea production.
28.10.6 Flavoured tea
Teas are sometimes scented with various plant essential oils such as lemon, bergamot, rose and fragrant olive which impart sweet floral attributes to enhance the natural flavour of tea.
Other teas are blended with flower petals, spices or dried leaf such as Rosemary, Peppermint, Camomile and Chrysanthemum.
28.10.7 Brick tea
These are tea (black or green) which are compressed in the form of bricks or cakes. Portions of bricks are broken off for use and are sometimes cooked with butter or other fats.
28.10.8 Instant tea
It is the water soluble extract of tea leaf, usually marketed as a powder, flake or granule, either pure or as a part of flavoured mixes.
Most Instant tea is made from black tea, but some is made from green tea. Iced lemon teas are popular example in USA.
28.10.9 Products promoted on health grounds
‘Decaffeinated tea’ is promoted on health grounds. Tea is decaffeinated with methylene chloride or other chlorinated solvents and supercritical CO2.
Flavours
The flavours used include chocolate, jasmine, mandarin orange peel, Bergamot and other sweet herbs. In India, cardamom, ginger, lemon, bergamot and mint are popular flavoured teas.