People are accustomed to seeing and using different kinds of instant coffee, but the development of instant teas has lagged far behind that of instant coffee market. In the case of instant tea, the liquor (tea brew) itself is further concentrated and dried to form a powder or granular product. Hot water soluble and cold water soluble instant teas are found in the market. Process of the production of instant tea consists of the following operations, selection of raw materials, extraction, aroma stripping, cream processing, concentration and drying. Criteria for the selection of the raw material include processing requirements of the market for which the tea is intended and the commercial restrictions placed upon manufacture. Instant tea can be made from black tea leaf, (partially) fermented, undried leaf, oolong or green tea. Manufacturers in tea producing countries use fermented undried leaf as a basis for instant black tea production, as this does not have to pass through the auctions and is therefore cheaper. As per the final user of the instant tea the demand for the type of instant tea varies as hot water soluble, cold water soluble and green instant teas.
Speciality and Herbal Teas:
These are classified according to the raw material used and the type of manufacture adopted. Orthodox processed tea leaves produce “particular” teas like semi-fermented oolongs and reprocessed, scented and compressed teas. Delicately plucked and processed teas make numerous “prominent” teas. The raw material is taken from the plants which are well grown in an excellent habitat with advantageous ecological conditions and are made skillfully and exquisitely with delicate flush buds and leaves of the tea plants belonging to fine varieties. Herbal teas are made by processing veritable teas together with medicinal herbs, which are used to complement the curative properties of the former for many ailments.
Utilization of tea extract in various fields has increased worldwide. The extract is used as dye, detergent, deodorant, sterilization agent and medical agent such as anti-dental caries agent and anti-inflammation agent. Green leaves of tea, oolong and black teas are used as raw materials of tea extract powder. The production system of tea extract powder is almost similar to that of instant tea; extraction with hot water or aqueous ethanol, separation, concentration and spray-drying. Green tea extract powder made by this process contains about 25-30 % of polyphenol and around 20% of catechin.
Use as Dye:
Wood, silk or synthetic yarn type fibres are dyed in tea extract solution (1:20) containing 10% of tea extract powder with met-mordant at 60°C for six hours. After washing, the dyed yarn with water, the yarn weight increased by 3-5%. By metal-mordants, the colour of yarn changes to pale green, yellow-green, yellow, brown and copper-yellow. It is found that despite repeated washing or exposure to sunlight for the fading test, the colour of yarn is maintained at least for one year.
Use as a Detergent:
Oolong tea extract has been developed as one of the effective substitutes for (CFC) chlorofluoro carbon used to wash away oil on chips used in display coated liquid crystal. The advantages of oolong tea extract as detergent are.
- it is an organic material and therefore ecofriendly and the waste water is easily disposed of
- it is a safe detergent which is non toxic and non-inflammable
- the extract forms a high quality detergent for washing oily substances
Tea Seed Oil:
Tea seeds are used as a source of supplementary protein and edible oil for human consumption, apart from many other industrial applications. The prospects of tea seed oil are immense. It can be a substitute for any edible oil; it can also be used as a cheaper alternative to olive oil which is mostly imported. Cosmetic industry may use it for manufacturing hair lotion, soap, etc. The thiosaponin has some medicinal value. It acts as an adjuvant, anti-inflammatory agent.
Tea oil cake and waste are used as fodder and bio-manuring. Manure produced from a mixture of green tea waste and fowl dropping is sold in the Japanese manure market and is used widely in kitchen gardens for flowers and vegetables.