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Instant tea extract manufacturing
Instant tea extract manufacturing
An object is to provide a preparation process of a green tea extract having a high non-polymer catechin concentration and tasting good with less bitterness and less astringency. The present invention relates to a preparation process of a green tea extract, which comprises subjecting an enzyme-inactivated raw tea leaves to CTC processing, drying the tea leaves until the water content thereof becomes 20 wt. % or less, and extracting the tea leaves while setting the weight ratio of an extraction solvent to the tea leaves to be extracted to 30 or less. Disclosed is a process comprising the steps of : expressing juice from fresh tea leaves thereby to produce leaf residue and tea juice, wherein the amount of expressed juice is between 10 and 300 ml per kg of the fresh tea leaves; and processing the leaf residue to produce leaf tea and/or a tea extract.
Although many consumers still enjoy beverages made from leaf tea, it is becoming increasingly popular to enjoy tea beverages prepared in more convenient ways. For example, tea beverages can be prepared from instant powders which are free from insoluble leaf tea and so dissolve rapidly and completely on contact with hot water. These powder products are usually manufactured by a process comprising extracting leaf tea with water and drying the resulting extract. Also popular are packaged ready-to-drink beverages which contain dissolved tea solids. Such ready-to-drink teas are usually manufactured from instant powders such as those described above or directly from extraction of tea leaf.
Consumers are also increasingly interested in foods and beverages which have undergone minimal processing and have a natural image and/or contain high levels of bioactive compounds. In view of this, efforts have been made to manufacture tea powders or ready-to-drink beverages from juice expressed from tea leaves as an alternative to tea extracts .
CN 1 718 030 A (LANCANGJIANG BEER ENTPR GROUP) discloses a green tea beverage prepared from fresh organic green tea leaves through breaking, squeezing to obtain tea juice, filtering, fine filtering by membrane, mixing it with water in ratio of 1: (15- 25) , membrane filtering for removing bacteria, and aseptic canning.
JP 11/056,243 A (NARA PREFECTURE) discloses a method for producing a powdery tea product containing increased amount of effective component and capable of keeping flavour, etc., over a long period by subjecting a pressed juice obtained by the successive steaming, grinding and pressing of raw tea leaves to ultrafiltration and reverse osmosis concentration treatment, adding a cyclodextrin to the concentrated liquid and drying the mixture.
Unfortunately, tea products made from tea juice have not yet enjoyed commercial success. This may be due, in part, to high wastage due to loss of tea material in the pressed leaf. As disclosed in JP 11/056,243 A, the tea leaves from these known processes still contain some effective components but are unable to be used as they are. Thus, it is suggested in JP 11/056,243 A to process the squeezed leaves into a fine powder and recombine with the powdered tea juice. Unfortunately, however, products which contain powdered insoluble tea leaf are only of limited popularity with consumers.
Therefore, we have identified that there is a need for a process for preparing tea products derived from tea juice, wherein the pressed tea leaves are not wasted but are used to manufacture tea products which retain the high value of traditional leaf tea (especially large leaf tea) or tea extracts. We have found that this need can be met by carefully controlling the way in which the juice is expressed such that the leaves are suitable for manufacture into tea products with a quality at least comparable to that of conventional tea products.
Instant tea extract manufacturing process
"Tea" for the purposes of the present invention means material from Camellia sinensis var. sinensis and/or Camellia sinensis var. assamica. Especially preferred is material from var. assamica as this has a higher level of tea actives than var. sinensis .
"Leaf tea" for the purposes of this invention means a tea product that contains tea leaves and/or stem in an uninfused form, and that has been dried to a moisture content of less than 30% by weight, and usually has a water content in the range 1 to 10% by weight (i.e. "made tea") .
"Green tea" refers to substantially unfermented tea. "Black tea" refers to substantially fermented tea. "Oolong tea" refers to partially fermented tea.
"Fermentation" refers to the oxidative and hydrolytic process that tea undergoes when certain endogenous enzymes and substrates are brought together, e.g., by mechanical disruption of the cells by maceration of the leaves. During this process colourless catechins in the leaves are converted to a complex mixture of yellow and orange to dark-brown polyphenolic substances. "Fresh tea leaves" refers to tea leaves and/or stem that have never been dried to a water content of less than 30% by weight, and usually have a water content in the range 60 to 90%.
As used herein the term "expressing juice" refers to squeezing out juice from fresh tea leaves using physical force, as opposed to extraction of tea solids with the use of a solvent. Thus the term "expressing" encompasses such means as squeezing, pressing, wringing, spinning and extruding. It is possible that a small amount of solvent (e.g. water) is added to the fresh leaves during the expression step. However, in order to prevent significant extraction of tea solids by the solvent, the moisture content of the leaves during expression is that of fresh tea leaves as defined hereinabove. In other words, during the expression step, the moisture content of the tea leaves is between 30 and 90% by weight, more preferably between 60 and 90%. It is also preferred that the fresh leaves are not contacted with non-aqueous solvent (e.g. alcohols) prior to or during expression, owing to the environmental & economic problems associated with such solvents.
Beverage As used herein the term "beverage" refers to a substantially aqueous drinkable composition suitable for human consumption.
Leaf Size and Grade
For the purposes of the present invention, leaf particle size is characterised by sieve mesh size using the following convention:
• Tyler mesh sizes are used throughout. • A "+" before the sieve mesh indicates the particles are retained by the sieve.
• A "-" before the sieve mesh indicates the particles pass through the sieve.
For example, if the particle size is described as -5 +20 mesh, then the particles will pass through a 5 mesh sieve (particles smaller than 4.0 mm) and be retained by a 20 mesh sieve (particles larger than 841 μm) .
Leaf particle size may additionally or alternatively be characterized using the grades listed in the international standard ISO 6078-1982. These grades are discussed in detail in our European patent specification EP 1 365 657 Bl (especially paragraph  and Table 2) which is hereby incorporated by reference.
Centrifuges for the Production of Tea Extract and Instant Tea
Instant tea is a soluble tea that is used in various beverages. As a rule, it is tea extract in powder or granulate form - for example lemon tea from a shop or supermarket.
Flottweg separators and decanters are used in three applications in the tea area:
- Producing tea extract
- Manufacturing instant tea
- Refining tea
Producing Tea Extract
In order to produce tea extract, it is necessary to extract the aqueous tea solution and concentrate the tea leaves. The decanter ensures optimum dewatering of the tea leaves and removes all residues, leaving none behind.
Your advantages in producing tea extract
- Very gentle treatment of the tea
- Maximum yield of tea extract
Manufacturing Instant Tea
The separator is used after tea extract has been obtained using a decanter. In order to manufacture instant tea, the separator separates off the fine and ultrafine solids. This produces a high-quality instant tea that meets all quality requirements.
Your Advantages In Manufacturing Instant Tea
- Very gentle treatment of the tea
- Maximum quality of the instant tea
When consumers pour hot water on their tea, they do not want to find any residues or turbidity. The tea should be clear and develop the required flavour. Refining with the separator represents the best solution for optimum tea clarification.
Your Advantages In Refining Tea
- Very gentle treatment of the product
- Maximum clarification of the tea
Your Partner For Producing Instant Tea And Tea Extract
We know about the quality requirements when manufacturing tea extract and instant tea. As a result, we strive to meet the specific requirements of the tea industry with our decanters and separators as effectively as possible. See for yourself the personal support that can be provided by our in-house project planning team.
Flottweg is certified to ISO 9001 and builds its decanters according to the latest technical standards - Made in Germany. Flottweg decanters and separators have been used successfully in the tea industry for many years. We offer you sound technical knowledge, personal support and well known references.
A novel technology for production of instant tea powder from the existing black tea manufacturing process
Pressed cake tea
Instant tea power and tea production process
Instant tea powder is the fully soluble solid of tea that has emerged as a new and fast growing product in every country. The various processes involved in the commercial production of instant tea include blending of tea leaves, hot water extraction, aroma recovery, soluble solids concentration, aroma restoration and dehydration. An envisaged process has been developed for the production of instant/soluble tea from the expressed juice of fermented tea leaves. Green tea leaves are subjected to withering, maceration, and fermentation process, which are similar to that of existing black tea production process. The fermented leaf is pressed to expel a part of juice containing soluble solids. The juice is then heated, centrifuged and vacuum dried to get soluble/instant tea powder. The pressed leaf residue is subjected to vacuum/hot air drying to obtain low grade conventional tea granules. About 20 ± 2 g of soluble tea and 220 ± 20 g of pressed cake tea are obtained from 1 kg of green tea leaves. The TF:TR ratio for soluble tea is 0.084 and that for pressed cake tea is 0.140.
The technology can be easily adopted by existing black tea manufacturers for simultaneous production of instant tea and black tea. The process is economical as both extracted juice and pressed cake are converted into value added products.
► Production of instant tea from the expressed juice of fermented tea leaves. ► TF:TR ratios for soluble tea and pressed cake tea are 0.084 and 0.140. ► About 20 ± 2 g of instant tea is obtained from 1 kg of tea leaves. ► About 220 ± 20 g of pressed cake tea is obtained from 1 kg of tea leaves.
Scientists perfect instant tea processing
Tea, Green tea, Sri Lanka
Scientists have developed a new technology to process instant tea. The invention is said to cut processing time by 15 hours, making it considerably less labour intensive and reducing costs. Developed by the Indian Institute of Technology, Kharagpur, West Bengal, the technology uses green tea leaves and buds, instead of the usual process of using manufactured black tea.
The process is also said to produce a more distinct aroma as well a full flavour. The method involves extracting the liquor from the processed leaves, tea wastes, or undried fermented leaves, concentrating the extract under low pressure, and drying the concentrate to a powder by freeze-drying, spray-drying, or vacuum-drying it. The steps involve obtaining freshly plucked green tea, crushing the leaves, extracting the juice and subjecting it to oxidation for an hour in a controlled chamber at a temperature of 30-35°C. After the oxidization process new compounds are formed, and the green juice turns coppery brown. The fermented or oxidized juice is then steamed and centrifuged to arrest fermentation and to remove the colloidal and suspended materials. The next step is to dry it to obtain instant tea. The residue of the leaves can then be subjected to fermentation and drying for manufacturing black tea, minimising on waste and contributing to further cost savings.
Tea is a popular daily beverage worldwide. Modulation and modifications of its basic components like catechins, alkaloids, proteins and carbohydrate during fermentation or extraction process changes organoleptic, gustatory and medicinal properties of tea. Through these processes increase or decrease in yield of desired components are evident. Considering the varied impacts of parameters in tea production, storage and processes that affect the yield, extraction of tea biomolecules at optimized condition is thought to be challenging. Implementation of technological advancements in green chemistry approaches can minimize the deviation retaining maximum qualitative properties in environment friendly way. Existed extraction processes with optimization parameters of tea have been discussed in this paper including its prospects and limitations. This exhaustive review of various extraction parameters, decaffeination process of tea and large scale cost effective isolation of tea components with aid of modern technology can assist people to choose extraction condition of tea according to necessity.
Prof. H. N. Mishra, who headed the development of the technology, said, "Fresh tea leaves contain about 75 per cent moisture. This extra moisture means that the leaves are easier to process, which in turn helps to speed up the time and adds to the quality of the tea". The scientists estimate that the cost of the technology is just about Rs. 1,00,000/- (€20,000). The institution had already received a patent for the process and is about to implement the technology at two Banglore based tea companies. World tea production has been dominated by Asian countries with China, India, Sri Lanka, Indonesia and Bangladesh. China was the largest producer where output was about 861,000 million tonnes in 2004 followed by India and Sri Lanka with 850,500 and 303,000 million tonnes respectively.