CN113973955B

CN113973955B - Tea concentrated solution and preparation method thereof

Info

Publication number: CN113973955B
Application number: CN202111210784.7A
Authority: CN
Inventors: 胡玉荣; 张顶武; 陈家伯
Original assignee: Shanghai Kangshi Food Technology Co ltd
Current assignee: Shanghai Kangshi Food Technology Co ltd
Priority date: 2021-10-18
Filing date: 2021-10-18
Publication date: 2024-09-13
Anticipated expiration: 2041-10-18
Also published as: CN113973955A

Abstract

The tea concentrate and the preparation method thereof in the specific embodiment of the invention are characterized in that finished tea leaves are moistened by water; then, under the pressure condition of 0.011-0.057 MPa, introducing steam to treat the tea leaves wetted by water, collecting steam condensate containing aroma components, thereby being beneficial to obtaining tea aroma recovery liquid with higher natural tea aroma, and simultaneously, under the pressure condition of 0.011-0.057 MPa, the temperature of the steam is lower, so that the problem that the temperature is too high to cause the decomposition of heat sensitive aroma to cause green odor can be prevented, and the aroma flavor is more natural.

Description

Tea concentrated solution and preparation method thereof

Technical Field

The invention belongs to the field of food and beverage, and particularly relates to a tea concentrated solution and a preparation method thereof.

Background

The tea beverage market has developed rapidly in recent years, and along with the improvement of the living standard of people, the requirements of consumers on the health, the nature and the taste quality of the tea beverage are also higher. Pure tea beverages are developed, the market share is gradually increased, no additive and pure nature are the main trend of the future development of tea beverages, but the sugar-free and essence-free tea beverage is difficult to meet the requirements on fragrance and taste by purely extracting tea leaves for blending, so that tea concentrated solution is added in the blending process to improve the taste of the product and increase the tea charm.

The concentrated tea liquid is prepared with tea or fresh tea leaf as main material and through water extraction or squeezing juice, and through adding food additive and food processing assistant, physical elimination of water and other steps.

However, because the aroma components of the tea have poor thermal stability and are easy to volatilize, most of the aroma of the tea is lost in the processes of long-time extraction, concentration and the like in the production process of the traditional tea concentrate, and the aroma is still needed to be added to supplement the aroma of the tea when the tea beverage is prepared by only using the concentrate.

The aroma in the tea can be recovered by utilizing a steam distillation method, the method adopted at present mainly comprises the step of carrying out steam distillation on raw tea or finished tea, and the steam distillation method is favorable for aroma recovery on raw tea, but has higher requirements on tea, and the domestic tea raw materials mainly comprise finished tea, so that the application range of the method is limited to a great extent, and the problem of low aroma recovery content of the finished tea exists in the current steam distillation method.

Disclosure of Invention

Aiming at the problems existing in the prior art when water vapor is adopted to recycle the aroma of tea, the specific embodiment of the invention provides the following tea concentrated solution and the preparation method thereof:

a preparation method of tea concentrate comprises the following aroma extraction steps:

Wetting finished tea leaves with water;

Then, under the pressure condition of 0.011-0.057 MPa, introducing the tea which is wetted by water for steam treatment, and collecting steam condensate containing aroma components to obtain aroma condensate A.

Optionally, the finished tea leaves are moistened with water at a temperature above 65 ℃.

Optionally, the length of the tea leaves is 1-5 mm.

Optionally, the preparation method further comprises the following extraction steps: the tea leaves treated by water vapor are mixed according to the weight ratio of the tea leaves to water of 1: 2-1: 10, extracting to obtain an extract B, wherein the extraction temperature is 25-90 ℃ and the extraction time is 1-60 min.

Optionally, the preparation method further comprises the following enzymolysis concentration steps: the extracted tea residues are mixed according to the weight ratio of tea to water of 1:5 to 1:10, leaching for 5-60 min at 70-95 ℃, cooling to 40-50 ℃, adding enzyme for enzymolysis, filtering tea residues after the enzymolysis is finished to obtain tea soup, and concentrating the tea soup until the content weight fraction of soluble solid solution is 30-50 wt% to obtain concentrated solution C.

Optionally, the filtering adopts the following modes: and (3) performing primary filtration by adopting a filter press, and performing centrifugal secondary filtration and cross-flow filtration.

Optionally, the enzymolysis adopts the following modes: firstly adding the tannin enzyme for enzymolysis for 10 min-1 h, and then adding the protease and pentosanase for enzymolysis for 0.5 h-3 h.

Optionally, the preparation method further comprises the following compounding steps: the aroma condensate A, the extract B and the concentrated solution C are mixed according to the proportion of 0.5 to 2:1 to 4: and the weight ratio of the components is 0.5 to 1.5.

A concentrated solution of tea is prepared from the concentrated solution of tea, the tea concentrate is prepared by the preparation method.

The tea concentrate and the preparation method of the specific embodiment of the invention are characterized in that finished tea leaves are moistened by water; then, under the pressure condition of 0.011-0.057 MPa, after the tea leaves which are wetted by water for vapor treatment are introduced, collecting vapor condensate containing aroma components, which is favorable for obtaining tea aroma recovery liquid with higher natural tea aroma, and meanwhile, under the pressure condition of 0.011-0.057 MPa, the temperature of the vapor is lower, so that the problem that the temperature is too high to easily cause the decomposition of some heat sensitive aroma to cause green odor can be avoided, and the aroma flavor is more natural.

Detailed Description

The inventor of the application finds that when the water vapor condensate containing aroma components is collected for collecting the aroma components of the tea after the finished tea is treated by the water vapor, because the process is in a high-temperature airtight environment, some heat-sensitive aroma components in the finished tea can change in structure due to heating, have great difference with aroma characteristics of tea raw materials, cause green odor, when the finished tea is wetted by water, and the pressure in the process is controlled to be 0.011-0.057 MPa, the vapor temperature of the corresponding water vapor under the pressure is 50-85 ℃, the low vapor temperature can effectively prevent the decomposition of the heat-sensitive aroma components, and meanwhile, the combination of the water wetting of the finished tea under low pressure can be more beneficial to the escape and collection of the aroma components in the tea. Thus, embodiments of the present application provide a method of preparing a tea concentrate comprising the following aroma extraction steps: wetting finished tea leaves with water; then, under the pressure condition of 0.011-0.057 MPa, introducing the tea which is wetted by water for steam treatment, and collecting steam condensate containing aroma components to obtain aroma condensate A.

In some embodiments, the aroma extraction system comprises a steam generator, a reactor, a condenser, a collector and vacuum equipment, wherein finished tea leaves are placed in the reactor, the reactor can be a column or a barrel container, for example, one end of the reactor is connected with the steam generator, the opposite end of the reactor is connected with the condenser, steam prepared by the steam generator enters the reactor and contacts with finished tea leaves in the reactor to extract aroma components in the tea leaves, then the steam and the aroma components enter the condenser to condense and liquefy, then the condensed and liquefied steam and aroma components are collected by the collector to obtain aroma condensate A, and in the preparation process, the pressure in the whole aroma extraction process is controlled to be in a negative pressure condition of 0.011-0.057 MPa by the vacuum equipment, for example, a vacuum pump. In some embodiments, the reactor is further provided with stirring means for stirring the finished tea leaves during the treatment of the finished tea leaves with steam in order to allow the finished tea leaves to be substantially more fully contacted with the steam.

In some embodiments, the finished tea is any one of green tea, oolong tea, black tea, etc., wherein the green tea may be any one of steamed green tea, roasted green tea, sun-dried green tea, etc., or a combination of two or more of them, the oolong tea may be any one of or a mixture of two or more of Minbei oolong tea, minnan oolong tea, guangdong oolong tea, gaoshan oolong tea, etc., and the black tea may be any one of congou black tea, black tea of a small variety, broken black tea, etc.

In some embodiments, 1 part by weight of the finished tea leaves is wetted with 0.1 to 10 parts by weight of water before being subjected to steam treatment, and specifically, for example, 1 part by weight of the finished tea leaves is subjected to spray wetting treatment with 0.1 part by weight, 0.5 part by weight, 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, 6 parts by weight, 7 parts by weight, 8 parts by weight, 9 parts by weight, 10 parts by weight, or the like of purified water before being subjected to steam treatment.

In some embodiments, the finished tea leaves are wetted with water at 25-95 ℃, in some embodiments, the finished tea leaves are wetted with water at 65 ℃ or more, and further wetted with water at 90 ℃ or more, and the temperature is more favorable for recycling and extracting aroma.

In some embodiments, the length of the finished tea leaves is 1-5 mm, and the length of the finished tea leaves can be obtained by cutting or crushing, for example, and the aroma recovery concentration can be higher by adopting the length of the finished tea leaves, so that higher aroma recovery efficiency can be achieved.

In some embodiments, the flow rate of the steam is 4kg/h to 95kg/h, and specifically, for example, may be 5kg/h, 10kg/h, 20kg/h, 30kg/h, 40kg/h, 60kg/h, 70kg/h, 80kg/h, 90kg/h, etc., based on 100kg of finished tea leaves, the recovery time is 0.5h to 2h, and the weight of the aroma condensate a is 50 kg to 200kg.

In some embodiments, the method of preparing a tea concentrate of embodiments of the present invention further comprises the steps of: the finished tea treated by water vapor is prepared by the following steps of: 2-1: 10, extracting to obtain an extract B, wherein the extraction temperature is 25-90 ℃ and the extraction time is 1-60 min. Through the extraction step, the finished tea leaves with the recovered aroma are subjected to short-time extraction for one time, and the obtained extract liquid has more natural tea flavor.

In some embodiments, the preparation method of the tea concentrate according to the present invention further comprises the following enzymatic concentration steps: the extracted tea residue is prepared according to the weight ratio of finished tea leaves to water of 1:5 to 1:10, leaching for 5-60 min at 70-95 ℃, cooling to 40-50 ℃, adding enzyme for enzymolysis, filtering tea residues after the enzymolysis is finished to obtain tea soup, and concentrating the tea soup until the content weight fraction of soluble solid solution is 30-50 wt% to obtain concentrated solution C. In some embodiments, the enzyme is added in an amount of 1wt% to 5wt% based on the weight of the finished tea leaf material. In some embodiments, the enzyme may be, for example, one or more of tannase, protease, pentosanase, pectinase, or glycogenolytic enzyme, etc. In some specific embodiments, the enzyme is added to carry out enzymolysis for 10min to 1h, and then protease and pentosanase are added to carry out enzymolysis for 0.5h to 3h. The addition amount of protease is 1-5wt% of the weight of the finished tea, the addition amount of pentosanase is 0.02-2wt% of the weight of the finished tea, the addition amount of tannase is 0.01-1wt% of the weight of the finished tea, the protease decomposes protein in the tea into amino acid, the delicate flavor of the tea is improved, the pentosanase has pectinase and various saccharifying enzyme activities, the cell wall is destroyed by utilizing various activities of the compound enzyme, the content of soluble solids in the tea is increased, the sweet feeling of the tea is increased, the tannase can improve the turbidity degree of the tea after cooling, the clarity is improved, and the bitter taste is reduced.

In some embodiments, the method for preparing the tea concentrate according to embodiments of the present invention, the filtration is performed in the following manner: the filter press is adopted for primary filtration, and after centrifugal secondary filtration, cross-flow filtration is carried out, and the clarity of tea soup can be obviously improved by adopting the mode of filtration.

In some embodiments, the method for preparing the tea concentrate according to the embodiment of the present invention further includes a sterilization step of sterilizing the filtered tea soup, and performing instantaneous heating high-temperature sterilization at a sterilization temperature: the sterilization is performed at 90-95 ℃ for 15-60 seconds, and in some embodiments, the sterilization comprises two steps, one sterilization is performed after one filtration, and one sterilization is performed after cross-flow filtration.

In some embodiments, the tea concentrate of the present invention is prepared by a rotary film evaporator at a concentration temperature of 30-70deg.C.

In some embodiments, the preparation method of the tea concentrate of the present invention further comprises the following compounding steps: the aroma condensate A, the extract B and the concentrated solution C are mixed according to the proportion of 0.5 to 2:1 to 4: the weight ratio of 0.5 to 1.5 is compounded, and the tea concentrated solution obtained by using the compound formula can achieve the optimal flavor effect.

In some embodiments, the method of preparing a tea concentrate of embodiments of the present invention further comprises the steps of: the compounded tea concentrated solution is subjected to heat sterilization, is rapidly cooled to 60-70 ℃ for hot canning, is then cooled to normal temperature, or is cooled to normal temperature and is then subjected to aseptic canning, and the heat sterilization adopts a plate type sterilizer or a tubular type sterilizer, or adopts a sterilizing kettle for sterilization after the product canning is completed.

The invention is further illustrated by the following examples.

Examples

Sensory evaluation

The weight fraction of the soluble solid solution in the tea concentrate was diluted to 0.3wt%, and the tea aroma, sweetness, fullness, bitterness and overall sensory flavor were evaluated by 10 fully trained panelists and the average score was recorded. The scoring criteria are: very good, 8-10 minutes; 6 to 8 minutes; slightly better, 4-6 minutes; slightly worse, 2-4 minutes; difference, 0-2 minutes; very poor, 0 minutes.

Example 1

Preparation of fragrance condensate A

In the reactor, 100kg of oolong tea leaves are put into the reactor, 100kg of RO water at 25+/-2 ℃, 65+/-2 ℃ and 95+/-2 ℃ is sprayed respectively, so that the tea leaves are uniformly wetted, the aroma recycling equipment is closed, the pressure is regulated to 0.024MPa, the steam temperature is 65+/-2 ℃, the steam flow is 95kg/h, and the aroma is recycled for 2h, so that aroma condensate A is obtained.

Preparation of extract B

Extracting the oolong tea leaves with sealed extraction equipment to recover aroma, adding 300kg RO water at 85+ -2deg.C, and extracting for 5min. And (5) separating tea from water after extraction to obtain an extract B.

Preparation of concentrate C

Adding 1000kg of RO water at 85+/-2 ℃ into the extracted tea residues, leaching for 15min, and cooling to 45 ℃ after extraction; firstly, adding 0.1kg of tannin enzyme, and carrying out enzymolysis reaction for 1h; 1.5kg of Protease (Protease A2SD, wild) and 0.6kg of pentosanase (Viscozyme L, noveXin) were added, and the enzymatic hydrolysis reaction was continued for 3 hours. The temperature of the enzymolysis reaction process is controlled at 45+/-2 ℃. After the enzymolysis reaction is finished, filtering by a filter press for one time, separating tea residues to obtain tea soup, sterilizing the tea soup at a high temperature by a plate sterilizer, sterilizing for 60s at 90 ℃, filtering for the second time by a disc centrifuge and a filter element filter, filtering by cross flow, fine filtering, sterilizing the fine filtrate at a high temperature by the plate sterilizer for 15s at 95 ℃, concentrating by a rotary evaporator at 30+/-2 ℃, and regulating concentration to 20-30wt% of soluble solid solution (Brix) to obtain concentrated solution C.

Compounding

Aroma condensate A, extract B and concentrated solution C are mixed according to the proportion of 1:1.5:1.5, compounding to obtain the high-aroma tea concentrated solution.

Finished product sterilization

Sterilizing the compounded high-aroma tea concentrated solution at high temperature by adopting a plate sterilizer, sterilizing for 30s at 110 ℃, rapidly cooling, hot canning at 60 ℃, cooling to room temperature, and finally obtaining the high-aroma oolong tea concentrated solution, and carrying out sensory evaluation on the high-aroma oolong tea concentrated solution, wherein the results are shown in the following table 1.

Comparative example 1

A comparative product 1 was obtained by performing the same operation as in example 1 except that the tea leaves were not moistened during the aroma recovery stage, and the sensory evaluation results were shown in Table 1 below.

Table 1 table of sensory scores and evaluation results of example 1 highly aromatic oolong tea concentrate and comparative example 1 comparative product 1

As is clear from the evaluation results of Table 1, in comparative example 1, the tea leaves were not sufficiently moistened, and the aroma of the dried tea was directly recovered, so that the obtained aroma had a remarkable flavor of the dried tea and was not natural enough as compared with the examples. In the embodiment 1, the oolong tea is fully wetted by water, and then the aroma is natural and rich, wherein the oolong tea is wetted by water at 65 ℃, and particularly the aroma strength and the aroma richness of the oolong tea wetted by water at 95 ℃ are better, which indicates that the water wetting at a higher temperature is more favorable for exciting the tea aroma of the oolong tea.

Example 2

Preparation of fragrance condensate A

Adding oolong tea leaves 100kg into a reactor, spraying with RO water 100kg at 95+ -2deg.C to uniformly wet the tea leaves, sealing the aroma recovery equipment, adjusting the pressure to 0.011MPa, 0.024MPa and 0.057MPa, respectively, and recovering aroma for 2h at 50+ -2deg.C, 65+ -2deg.C and 85+ -2deg.C at steam flow of 95kg/h to obtain aroma condensate A.

Preparation of extract B

Preparation of concentrate C

Adding 1000kg of RO water at 95+/-2 ℃ into the extracted tea residues, leaching for 5min, and cooling to 45 ℃ after extraction; firstly adding 0.03kg of tannin enzyme, and carrying out enzymolysis reaction for 1h; 1.5kg of Protease (Protease A2SD, wild) and 0.4kg of pentosanase (Viscozyme L, noveXin) were added, and the enzymatic hydrolysis reaction was continued for 3 hours. The temperature of the enzymolysis reaction process is controlled at 45+/-2 ℃. After the enzymolysis reaction is finished, filtering by a filter press for one time, separating tea residues to obtain tea soup, sterilizing the tea soup at a high temperature by a plate sterilizer, sterilizing for 30s at 90 ℃, filtering for the second time by a disc centrifuge and a filter element filter, filtering by cross flow, fine filtering, sterilizing the fine filtrate at a high temperature by the plate sterilizer for 15s at 95 ℃, concentrating by a rotary evaporator at 60+/-2 ℃, and regulating concentration to obtain a soluble solid solution (Brix) of 20-30wt%, thereby obtaining a concentrated solution C.

Compounding

Aroma condensate A, extract B and concentrated solution C are mixed according to the proportion of 1:1.5:1, compounding to obtain the high-aroma tea concentrated solution.

Finished product sterilization

Sterilizing the compounded high-aroma tea concentrated solution at high temperature by adopting a plate sterilizer, sterilizing for 20s at 115 ℃, rapidly cooling, hot canning at 70 ℃, cooling to room temperature, and finally obtaining the high-aroma oolong tea concentrated solution, and carrying out sensory evaluation on the high-aroma oolong tea concentrated solution, wherein the results are shown in the following table 2.

Comparative example 2

The operation exactly identical to that of example 2 was conducted except that the aroma recovery apparatus was sealed and the pressures were adjusted to 0.005MPa, 0.068MPa and 0.1MPa (atmospheric pressure), respectively, at the aroma recovery stage, corresponding to the steam temperatures of 45.+ -. 2 ℃, 90.+ -. 2 ℃ or 100.+ -. 2 ℃ to prepare comparative product 2, and the results of the sensory evaluation are shown in Table 2 below.

Table 2 table of sensory scores and evaluation results of example 2 highly aromatic oolong tea concentrate and comparative example 2 comparative product 2

As can be seen from the evaluation results of Table 2, in example 2, the oolong tea was sufficiently moistened with RO water at 95℃and then subjected to aroma recovery under the pressure conditions of 0.011MPa, 0.024MPa and 0.057MPa, and after the aroma recovery was combined with the flavor extract and the taste concentrate, the tea aroma of the obtained oolong tea was natural and intense, and the characteristic flavor of oolong tea was obvious, and a higher evaluation was obtained. Wherein, the oolong tea is subjected to aroma recovery under the pressure conditions of 0.011MPa and 0.057MPa, and the aroma is natural and strong, but the aroma strength is slightly inferior to that of the oolong tea under the pressure condition of 0.024MPa, so that the aroma recovered under the pressure condition of 0.024MPa is optimal. In comparative example 2, aroma recovery was performed under normal pressure or pressure was adjusted, aroma recovery was performed under 0.068MPa pressure, and the recovered aroma was possibly blue odor due to too high steam temperature, and the damage of tea leaves was serious due to too high temperature, the bitterness of the flavor extract and the concentrate was slightly stronger than that of the examples, and aroma was recovered under 0.005MPa steam, and tea aroma was natural, but the intensity of the recovered aroma was weak, and had a certain influence on the characteristic aroma flavor of oolong tea.

Example 3

The same operations as in example 1 were carried out except that the oolong tea leaf was replaced with green tea leaf in example 1, and the sensory evaluation results of the obtained high-aroma green tea concentrate were shown in table 3 below.

Example 4

The same operations as in example 1 were carried out except that the oolong tea leaf was replaced with black tea leaf in example 1, and the obtained highly aromatic black tea concentrate was subjected to sensory evaluation, and the results are shown in table 3 below.

Table 3 table of sensory scores and evaluation results for example 3 high aroma green tea concentrate and example 4 high aroma black tea concentrate

As can be seen from the evaluation results of Table 3, in example 3, the green tea was sufficiently wetted with water at 25℃and 65℃and 95℃to give a concentrated solution having a natural and intense tea aroma. Wherein, the green tea is wetted by water at 25 ℃ and has natural and intense aroma, but the aroma intensity is slightly inferior to the aroma recovered after the high temperature water wetting treatment, the aroma intensity is high after the high temperature water wetting treatment, but the natural sense of aroma is slightly inferior to the aroma recovered after the low temperature water wetting treatment, and the aroma recovered after the water wetting treatment at 65 ℃ is the best. In example 4, the black tea was sufficiently moistened with water at 25 ℃, 65 ℃ and 95 ℃ to give a concentrated solution having a natural and intense tea aroma. Wherein, the black tea is wetted by water at 25 ℃ and 65 ℃ and has natural and rich aroma, but the aroma strength and the richness are slightly inferior to those of the aroma recovered after the high-temperature water wetting treatment, and the aroma flavor recovered after the 95 ℃ water wetting treatment is optimal.

Comparative example 3

The procedure fully as in example 1 was followed except that extract B was not prepared and the tea leaves were sufficiently wetted with 95℃water, and the obtained oolong tea concentrate was subjected to sensory evaluation, and the results are shown in Table 4 below.

Comparative example 4

The same operations as in example 1 were carried out except that 0.6kg of pentosanase (Viscozyme L, noveXin) was not added and that the tea leaves were sufficiently wetted with 95℃water in example 1, and the obtained oolong tea concentrate was subjected to sensory evaluation, and the results are shown in Table 4 below.

Table 4 comparative examples 3 and 4 sensory scores and evaluation results table of oolong tea concentrates

As can be seen from the evaluation results of Table 4, in comparative example 4, the preparation of extract B was not performed, and the natural flavor of a part of oolong tea was absent, the sweetness and sweetness were slightly weaker than those of examples, the aroma was less intense than that of example 1, and the fullness and tea feel of tea soup were slightly weaker. In comparative example 5, pentosanases were not used in the enzymatic hydrolysis stage, and the sweetness and fullness at the inlet were slightly weaker than those in example 1.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims

1. A method of preparing a tea concentrate comprising:

Fragrance extraction: wetting finished tea leaves with water; then, under the pressure condition of 0.011-0.057 MPa, introducing the tea which is wetted by water for steam treatment, and collecting steam condensate containing aroma components to obtain aroma condensate A;

Extraction: the tea leaves treated by water vapor are mixed according to the weight ratio of the tea leaves to water of 1: 2-1: 10, extracting to obtain an extract B, wherein the extraction temperature is 25-90 ℃ and the extraction time is 1-60 min;

Enzymolysis concentration: the extracted tea residues are mixed according to the weight ratio of tea to water of 1:5 to 1:10, leaching for 5-60 min at 70-95 ℃, cooling to 40-50 ℃, adding tannin enzyme for enzymolysis for 10-1 h, adding protease and pentosanase for enzymolysis for 0.5-3 h, filtering tea residues after enzymolysis is finished to obtain tea soup, and concentrating the tea soup until the content weight fraction of soluble solid solution is 30-50 wt%, thus obtaining concentrated solution C;

And (3) compounding: the aroma condensate A, the extract B and the concentrated solution C are mixed according to the proportion of 0.5 to 2:1 to 4: and the weight ratio of the components is 0.5 to 1.5.

2. A method of preparation as claimed in claim 1 wherein the finished tea leaves are wetted with water at 65-95 ℃.

3. The process according to claim 1, wherein the tea leaves have a length of 1 to 5mm.

4. The method of claim 1, wherein the filtering is performed by: and (3) performing primary filtration by adopting a filter press, and performing centrifugal secondary filtration and cross-flow filtration.

5. A tea concentrate, characterized in that it is prepared by the preparation method of any of claims 1-4.