DESC:The present disclosure relates to a process for preparing tea powders. In particular, the present disclosure relates to a process for manufacturing hot and cold water soluble tea powders from green tea leaves.

BACKGROUND

Tea is a very popular beverage that is consumed all over the world. Generally, for preparing tea, tea leaves are soaked in hot water or boiled in water. The spent tea leaves are then removed to get tea. This tea is consumed as it is or other ingredients such as spices, mint leaves, milk or sugar are added to enhance its aroma and taste.
In recent years, the popularity of soluble or instant tea has increased due the convenience of its use. Various methods for preparing soluble or instant tea are known. Traditionally, soluble or instant tea is made from tea waste or residual teas.

As tea waste or residual teas are used, low quality of soluble tea is obtained. As a result, in most commercially available instant teas various unnatural edible chemicals such as colours and artificial flavours are added in large quantities to enhance its flavour and aroma. Additionally, said methods require a large quantity of tea waste, making the process inefficient.

Other methods such as those described in US20010033880, require use of chemicals such as ascorbic acid, dehydroascorbic acid, 1-scorbamic acid, 5-phenyl-3, 4-diketo-gamma-butyrolactone or their salts for production of cold water soluble tea powder.

SUMMARY

The disclosure provides a process for manufacturing soluble tea powder. The process comprises withering freshly plucked tea leaves; macerating the withered tea leaves; fermenting the macerated tea leaves and extracting the soluble tea material from the fermented tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after fermenting the macerated tea leaves; separating the tea leaves and other insoluble material from the tea extract; concentrating the tea extract to obtain a concentrated tea extract wherein the concentration of soluble tea material is in a range from 20 to 40%; and drying the concentrated tea extract to obtain soluble tea powder.

The disclosure provides a process for manufacturing soluble tea powder. The process comprises steaming freshly plucked tea leaves; macerating the withered tea leaves; extracting soluble tea material from the macerated tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after macerating the steamed tea leaves; separating the tea leaves and other insoluble material from the tea extract; concentrating the tea extract to obtain a concentrated tea extract wherein the concentration of soluble tea material is in a range from 20 to 40%; and drying the concentrated tea extract to obtain soluble tea powder.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the present disclosure. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive manner, simply because it is being utilized in conjunction with a detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention may include several features, no single one of which is solely responsible for its desirable attributes, or which is essential to practicing the inventions herein described.

It will be understood by those skilled in the art that the foregoing general description and the following detailed description are explanatory of the invention and are not intended to be restrictive thereof.

The terms “a,” “an,”, and “the” are used to refer to “one or more” (i.e., to at least one) of the grammatical object of the article.
Reference throughout this specification to “an aspect”, “another aspect” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion and are not intended to be construed as “consists of only”, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such process or method.

Likewise, the terms “having” and “including”, and their grammatical variants are intended to be non-limiting, such that recitations of said items in a list are not to the exclusion of other items that can be substituted or added to the listed items.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the disclosure, the preferred methods, and materials are now described.

In its broadest, the present disclosure provides a process for manufacturing soluble tea powder comprising the steps of extracting soluble tea material from freshly processed tea leaves that have not been dried with hot water to give a tea extract, removing the tea leaves and other insoluble material from the tea extract, concentrating the tea extract, and drying the concentrated tea extract to obtain soluble tea powder.

“Tea” for the purposes of the present disclosure means leaf material from Camellia sinensis var. sinensis or Camellia sinensis var. assamica. “Tea” is also intended to include the product of blending two or more of any of these teas.
“Leaf tea” for the purposes of this disclosure means a tea product that contains one or more tea origins in an uninfused form.

“Soluble tea powder” for the purposes of this disclosure means tea powder that can be dissolved in water. The water includes both hot water and cold water.

The process of preparing the soluble tea power will now be disclosed in detail. The process comprises:
- processing the tea leaves;
- extracting soluble tea material from the processed tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after processing the tea leaves;
- separating the tea leaves and other insoluble material from the tea extract;
- concentrating the tea extract to obtain a concentrated tea extract; and
- drying the concentrated tea extract to obtain soluble tea powder.

In one embodiment, the processing of tea leaves comprises the steps of, withering the tea leaves, subjecting the withered leaves to maceration, and fermenting the macerated tea leaves. In such embodiments, the process for manufacturing soluble tea powder comprises:
- withering freshly plucked tea leaves;
- macerating the withered tea leaves;
- fermenting the macerated tea leaves;
- extracting soluble tea material from the fermented tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after fermenting the macerated tea leaves;
- separating the tea leaves and other insoluble material from the tea extract;
- concentrating the tea extract to obtain a concentrated tea extract; and
- drying the concentrated tea extract to obtain soluble tea powder.

In an alternate embodiment, the processing of tea leaves comprises of steaming the tea leaves and macerating the tea leaves by breaking the tissue in the tea leaves. In such embodiments, the process for manufacturing soluble tea powder comprises:
- steaming freshly plucked tea leaves;
- macerating the withered tea leaves;
- extracting soluble tea material from the macerated tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after macerating the tea leaves;
- separating the tea leaves and other insoluble material from the tea extract;
- concentrating the tea extract to obtain a concentrated tea extract; and
- drying the concentrated tea extract to obtain soluble tea powder.

Withering

In the first step of the process, plucked tea leaves are withered. Withering is a process whereby the plucked tea leaves are stored for periods of time, during which they undergo various biochemical and physical changes which often includes loss of moisture. In an embodiment, the plucked tea leaves consist of the first four leaves of the tea plant. In an alternate embodiment, the plucked tea leaves further comprise of courser tea leaves.

In an embodiment, a two-stage withering process is carried out in which in the first stage chemical withering is carried out for a period of 12 to 16 hours in atmospheric cold air. In the second stage physical withering is carried out for a period of 3 to 4 hours. Physical withering is carried out for 3 to 4 hours prior to start of processing of green tea leaves at temperature of about 97 degree centigrade by using dehumidified air at the rate of approximately 10 % of normal airflow in a withering trough. In an embodiment, gas burners are used for dehumidifying the atmospheric air. The time duration of physical withering is decided by using dry and wet bulb meter for measuring the ratio of moisture in the atmospheric air.

Tissue Breaking or Maceration process:

In the next step the withered leaves are subjected to maceration. In this process, tea juice inside the tissue of the tea leaf is exposed to atmospheric oxygen. The withered tea leave is moderately pressed for crushing the tissue cells. This makes the leaf twisted and the semi-permeable membrane of the leaf gets distorted allowing the cell juices to be expelled to cover the leaf surface. This allows the juice to mix with cellular enzyme in presence of oxygen and the chemical reactions necessary for fermentation commences.

Fermentation

In fermentation the macerated tea leaves are fermented till the colour of leaves turns golden brown. In an embodiment, the tea leaves are fermented for a period of 45 minutes to 105 minutes. In an embodiment, the fermentation is carried out in a humidified area wherein air in the area is changed at the rate of about 14 times per minute. The fermentation area is kept at temperature which is lower that the atmospheric temperature by about 7 to 10 degree Celsius. For keeping the fermentation area around 7 to 10 degree Celsius below the atmospheric temperature, humidified air is poured into the area.

Extraction

In the next step of the process, soluble tea powder is obtained from the processed tea leaves. The process comprises of extracting soluble tea material from freshly processed tea leaves, immediately after processing the tea leaves such that the processed tea leaves that have not been dried (never dried freshly fermented tea leaves, or freshly macerated tea leaves) with hot water to give a tea extract, separating the insoluble components from the tea extract, concentrating the tea extract, and drying the concentrated tea extract to obtain soluble tea powder.

In one embodiment, the macerated tea leaves immediately after macerating without drying are soaked in hot water at a temperature between 60 and 100oC to extract the water-soluble components from the tea leaves to obtain a tea extract.

In an alternate embodiment, fermented tea leaves immediately after fermenting without drying are soaked in hot water at temperatures in the range between 60 and 100oC to extract the water-soluble components from the tea leaves to obtain a tea extract.

By using fresh macerated tea leaves or fresh fermented tea leaves immediately after macerating or fermenting tea leaves i.e., without drying the macerating or fermenting tea leaves, for extraction maximum amount of water-soluble components are extracted into water. This results in the high retention of flavor and aroma components in the cup fully intact viz-a-viz the commercial methods that require addition of artificial flavor. This makes the process highly efficient. It is estimated that from the disclosed process about 2,500 to 4,000 cups of tea can be obtained from one kg of processed tea leaves viz-a-viz 250 to 450 cups of tea that are obtained from the same amount of orthodox or CTC tea respectively. Moreover, this process does not require fine plucking of tea leaves such as that required for orthodox or CTC tea, as this method can also be used for coarser tea leaves, making it economical.

In an embodiment, the extraction is carried out within a range of 1 to 4 hour of fermenting the macerated tea leaves. In some embodiments, the extraction is carried out within 1 hour of fermenting the macerated tea leaves.

In an embodiment, the extraction is carried out within a range of 1 to 4 hour of macerating the steamed tea leaves. In some embodiments, the extraction is carried out within 1 hour of macerating the steamed tea leaves.

In an aspect, extraction is carried out at least two times for maximum extraction of the water-soluble components from the tea leaves.

Separation of extract from the insoluble material

In the next step of the process, insoluble material such as the tea leaves is separated from the extract. Any method for separating the extract from the insoluble material may be utilized. Such methods include but are not limited to filtration, decantation or centrifugation. In an embodiment, extract is deleafed in a squeezing process followed by filtration to remove the un-soluble components.

Evaporation

The extract obtained after the separation of insoluble material is then concentrated to concentrations varying between 25 to 40% of soluble products to obtain concentrated tea extract solution. In some embodiments, the extract obtained after the separation of insoluble material is then concentrated to concentrations varying between 30 to 35% of soluble products to obtain concentrated tea extract solution.
In an embodiment, the concentration is carried out by evaporation. In another embodiment, the concentration is carried out in multistage evaporators.

Spray Drying

The concentrated tea extract solution is then spray dried to obtain soluble tea powder. In an embodiment the spray drying is done at temperatures in the range of 170 to 200 degree C temperatures to maintain the properties of the product.

In accordance with an aspect, before the concentrated tea extract solution is dried, aroma and/or flavour may be added to the concentrated tea extract.

The following examples illustrate certain embodiment and aspects of the present invention and not to be construed as limiting the scope thereof.

Examples

Example 1: Preparation of soluble tea powder in accordance with an embodiment

The raw material used in the process was green tea leaves sourced from small tea growers gardens of Assam. The green tea leaves where subjected to withering followed by macerating and fermentation. The green leaf tea material was subjected to extraction with hot water in a jacketed vessel for five to ten minutes or more at +90°C. After extraction the slurry was deleafed in a squeezing process and the hot liquor was passed through a filter to remove the in-solubles. It was then concentrated in a falling film evaporator, then taken for further process by spray dryer to obtain the tea powder. The powder we found was dark brown in colour.

Comparison of tea liquor and other properties of tea powders.

The data on the properties of the aqueous infusion (drink) obtained from tea powders prepared by the process of the invention by green tea leaf (1) as well as processes outside the invention by tea waste or residue teas (2) are presented in Table below.

Inventive example (1) Comparative example (2)
Polyphenols 30+ 18-
Theaflavin-to-thearubigin ratio (TF/TR) Ratio Balanced Poor
P. Side & W. Side Chemical No Yes
Metal No Yes
Aroma Natural Artificial
Medical values Present Nil
Food Colors No Yes
Edible chemicals No Yes
Masala & Other teas Natural Essence

The table above clearly indicates that in the inventive example (1) provides better results over as compared to comparative example (2) which uses tea waste or residue teas for preparing tea powders.

Specific embodiments are disclosed hereinafter

A process for manufacturing soluble tea powder, comprising:
- withering freshly plucked tea leaves;
- macerating the withered tea leaves;
- fermenting the macerated tea leaves and extracting the soluble tea material from the fermented tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after fermenting the macerated tea leaves;
- separating the tea leaves and other insoluble material from the tea extract;
- concentrating the tea extract to obtain a concentrated tea extract wherein the concentration of soluble tea material is in a range from 20 to 40%; and
- drying the concentrated tea extract to obtain soluble tea powder.

A process for manufacturing soluble tea powder, comprising:
- steaming freshly plucked tea leaves;
- macerating the withered tea leaves;
- extracting soluble tea material from the macerated tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after macerating the withered tea leaves;
- separating the tea leaves and other insoluble material from the tea extract;
- concentrating the tea extract to obtain a concentrated tea extract wherein the concentration of soluble tea material is in a range from 20 to 40% %; and
- drying the concentrated tea extract to obtain soluble tea powder.

Such process(s), wherein the soluble tea material is extracted from the macerated tea leaves by soaking the macerated tea leaves in hot water at temperatures in the range between 60 and 100oC for a period in the range from 5 minutes to 1 hour.

Such process(s), wherein the process of extraction is carried out at least two times.

Such process(s), wherein soluble tea material is concentrated in the range from 30 to 35%.

Such process(s), wherein the concentrated tea extract is spray dried at a temperature in the range of 170 to 200oC to obtain soluble tea powder.

Such process(s), wherein the extraction is carried out within a range of 1 to 4 hour of fermenting the macerated tea leaves.

Such process(s), wherein the extraction is carried out within a range of 1 to 4 hour of macerating the steamed tea leaves.

A soluble tea powder as obtained from processes as disclosed.

INDUSTRIAL APPLICABLITY

The process as disclosed allows for the manufacture of water-soluble tea powders in an easy and efficient manner. Since the process uses freshly processed tea leaves such as freshly processed fermented tea leaves instead of dried tea such as CTC or waste tea powder for extraction, higher concentration of soluble components is obtained in the extract. This results in the high retention of flavor and aroma components in the cup filly intact viz-a-viz the commercial methods that require addition of artificial flavor. This makes the process highly efficient. It is estimated that from the disclosed process about 2,500 to 4,000 cups of tea can be obtained from one kg of processed tea leaves. On the contrary only 250 to 450 cups of tea are obtained from the same amount of orthodox or CTC tea respectively. Moreover, this process does not require fine plucking of tea leaves such as that required for orthodox or CTC tea, as this method can also be used for coarser tea leaves, making it economical.
,CLAIMS:1. A process for manufacturing soluble tea powder, comprising:
- withering freshly plucked tea leaves;
- macerating the withered tea leaves;
- fermenting the macerated tea leaves and extracting the soluble tea material from the fermented tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after fermenting the macerated tea leaves;
- separating the tea leaves and other insoluble material from the tea extract;
- concentrating the tea extract to obtain a concentrated tea extract wherein the concentration of soluble tea material is in a range from 20 to 40%; and
- drying the concentrated tea extract to obtain soluble tea powder.

2. A process for manufacturing soluble tea powder, comprising:
- steaming freshly plucked tea leaves;
- macerating the withered tea leaves;
- extracting soluble tea material from the macerated tea leaves with hot water to obtain a tea extract, wherein the extraction is carried out immediately after macerating the withered tea leaves;
- separating the tea leaves and other insoluble material from the tea extract;
- concentrating the tea extract to obtain a concentrated tea extract wherein the concentration of soluble tea material is in a range from 20 to 40% %; and
- drying the concentrated tea extract to obtain soluble tea powder.

3. The process as claimed in claim 1 or 2, wherein the soluble tea material is extracted from the macerated tea leaves by soaking the macerated tea leaves in hot water at temperatures in the range between 60 and 100oC for a period in the range from 5 minutes to 1 hour.

4. The process as claimed in claims 1 or 2, wherein the process of extraction is carried out at least two times.

5. The process as claimed in claim 1 or 2, wherein soluble tea material is concentrated in the range from 30 to 35%.

6. The process as claimed in claim 1 or 2, wherein the concentrated tea extract is spray dried at a temperature in the range of 170 to 200oC to obtain soluble tea powder.

7. The process as claimed in claim 1, wherein the extraction is carried out within a range of 1 to 4 hour of fermenting the macerated tea leaves.

8. The process as claimed in claim 2, wherein the extraction is carried out within a range of 1 to 4 hour of macerating the steamed tea leaves.

9. A soluble tea powder as obtained from processes as claimed in claim 1 or 2.