Preparation method of concentrated liquid tea bag
By using weak acidic solution and reduced pressure reflux extraction technology in the preparation of concentrated liquid tea bags, the problems of incomplete extraction of active ingredients and weak antioxidant capacity in traditional methods are solved, achieving more efficient extraction and significantly improved product health benefits .
Patent Information
- Application Number
- CN202411802105.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-02-07
AI Technical Summary
In the traditional preparation method of concentrated liquid tea bags, the active ingredients are incompletely extracted, easily damaged, and have weak antioxidant ability, which limits product quality improvement and market expansion.
Weak acidic solution is used for room temperature soaking, combined with the reduced pressure reflux extraction technology under specific parameters, and through two extractions with different conditions, the extraction efficiency and comprehensiveness are improved to avoid the damage of active ingredients.
It significantly improves the antioxidant ability and health care effects of concentrated liquid tea bags, improves extraction efficiency and product quality, and makes up for the shortcomings of the existing technology.
Smart Images
Figure CN119385227A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of tea processing, and in particular to a method for preparing a concentrated liquid tea bag. Background Art
[0002] In the fast-paced modern life, tea drinks are widely loved for their unique taste and rich health functions. As consumers' pursuit of healthy diets increases, concentrated liquid tea bags, as a convenient and efficient form of tea drinks, have gradually become a popular product on the market. However, the traditional preparation methods of concentrated liquid tea bags often have some problems, such as incomplete extraction of active ingredients, easy destruction, and weak antioxidant capacity of the product. These problems seriously restrict the improvement of the quality of concentrated liquid tea bags and the expansion of the market.
[0003] Traditionally, tea leaves are extracted by water distillation or alcohol distillation, but these methods often need to be carried out at high temperatures, which can easily lead to the destruction of active ingredients in tea leaves (such as tea polyphenols, catechins, etc.), thus affecting the health benefits of the product. In addition, traditional extraction methods often do not handle tea leaves carefully enough, resulting in low extraction efficiency, and the extract contains a high level of impurities, affecting the purity and taste of the product.
[0004] In order to solve the above problems, the industry has been continuously exploring and improving. Among them, the vacuum reflux extraction technology has gradually attracted attention because it can achieve efficient extraction at a lower temperature and has less damage to the active ingredients. However, the existing vacuum reflux extraction technology still has some shortcomings in practical applications, such as insufficient optimization of extraction conditions and the need to improve extraction efficiency.
[0005] Therefore, there is an urgent need for a new method for preparing concentrated liquid tea bags to achieve efficient and complete extraction of active ingredients in tea leaves and significantly improve the antioxidant capacity and health benefits of the product. Summary of the invention
[0006] In order to solve the above problems, the present invention provides a method for preparing a concentrated liquid tea bag.
[0007] The present invention provides a method for preparing a concentrated liquid tea bag, which comprises the following steps:
[0008] The tea leaves are crushed, and then added into an acidic solution for soaking at room temperature to obtain a mixed liquid;
[0009] The mixed liquid is subjected to a first decompression reflux extraction, and then filtered and separated to obtain a first extract and a first extraction residue;
[0010] Performing a second reduced-pressure reflux extraction on the first extraction residue to obtain a second extract;
[0011] combining and concentrating the first extract and the second extract to obtain the concentrated liquid tea bag;
[0012] Among them, the working condition parameters of the first reduced pressure reflux extraction include: pressure of 3~7KPa, temperature of 35~45℃; the working condition parameters of the second reduced pressure reflux extraction include: pressure of 26~35KPa, temperature of 65~77℃.
[0013] Furthermore, the working condition parameters of the first reduced pressure reflux extraction include: pressure of 5 KPa and temperature of 40°C; the working condition parameters of the second reduced pressure reflux extraction include: pressure of 30 KPa and temperature of 73°C.
[0014] Furthermore, the first reduced pressure reflux extraction is performed for 60 to 90 minutes and for 1 to 3 times.
[0015] Furthermore, the second reduced pressure reflux extraction is performed for 30 to 60 minutes and for 1 to 3 times.
[0016] Furthermore, the tea leaves include at least one of green tea, white tea, black tea, oolong tea and dark tea.
[0017] Furthermore, the tea leaves are composed of green tea, dark tea and black tea in a weight ratio of (1-2):(5-8):(1-2).
[0018] Furthermore, the acidic solution is prepared by compounding malic acid, citric acid and water in a volume ratio of (5-10):(5-10):100.
[0019] Furthermore, the weight ratio of the tea leaves to the acidic solution is 1:(10-15).
[0020] Furthermore, the soaking time at room temperature is 12 to 24 hours.
[0021] Furthermore, the Brix of the concentrated liquid tea bag is 5-50%.
[0022] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:
[0023] The embodiment of the present invention provides a method for preparing a concentrated liquid tea bag. By using a weakly acidic solution as an extraction solvent and coordinating a reduced pressure reflux extraction method under specific parameters, and by selecting specific extraction conditions and solvents, the damage to the active ingredients in tea leaves caused by factors such as high temperature, high pressure and oxidation is effectively avoided. The use of an acidic solution also helps to protect the active ingredients from being affected by enzymatic hydrolysis. The reduced pressure reflux extraction technology reduces the boiling point of the solvent, so that efficient extraction can be achieved at a lower temperature, effectively avoiding the destruction of the active ingredients in tea leaves. At the same time, two extractions under different conditions can extract active ingredients of different properties in tea leaves respectively, thereby improving the comprehensiveness and efficiency of the extraction, and significantly improving the antioxidant capacity of the obtained concentrated liquid tea bag, thereby enhancing its health care effect and making up for the shortcomings of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.
[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0026] Figure 1 A schematic flow chart of a method for preparing a concentrated liquid tea bag provided in an embodiment of the present invention. DETAILED DESCRIPTION
[0027] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0028] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.
[0029] The present invention provides a method for preparing a concentrated liquid tea bag, such as Figure 1 As shown, the preparation method of the concentrated liquid tea bag comprises the following steps:
[0030] The tea leaves are crushed, and then added into an acidic solution for soaking at room temperature to obtain a mixed liquid;
[0031] The mixed liquid is subjected to a first decompression reflux extraction, and then filtered and separated to obtain a first extract and a first extraction residue;
[0032] Performing a second reduced-pressure reflux extraction on the first extraction residue to obtain a second extract;
[0033] combining and concentrating the first extract and the second extract to obtain the concentrated liquid tea bag;
[0034] Among them, the working condition parameters of the first reduced pressure reflux extraction include: pressure of 3~7KPa, temperature of 35~45℃; the working condition parameters of the second reduced pressure reflux extraction include: pressure of 26~35KPa, temperature of 65~77℃.
[0035] The embodiment of the present invention provides a method for preparing a concentrated liquid tea bag. By using a weakly acidic solution as an extraction solvent and coordinating a reduced pressure reflux extraction method under specific parameters, and by selecting specific extraction conditions and solvents, the damage to the active ingredients in tea leaves caused by factors such as high temperature, high pressure and oxidation is effectively avoided. The use of an acidic solution also helps to protect the active ingredients from being affected by enzymatic hydrolysis. The reduced pressure reflux extraction technology reduces the boiling point of the solvent, so that efficient extraction can be achieved at a lower temperature, effectively avoiding the destruction of the active ingredients in tea leaves. At the same time, two extractions under different conditions can extract active ingredients of different properties in tea leaves respectively, thereby improving the comprehensiveness and efficiency of the extraction, and significantly improving the antioxidant capacity of the obtained concentrated liquid tea bag, thereby enhancing its health care effect and making up for the shortcomings of the prior art.
[0036] In some specific embodiments, the working condition parameters of the first reduced pressure reflux extraction include: pressure of 5 KPa and temperature of 40°C; the working condition parameters of the second reduced pressure reflux extraction include: pressure of 30 KPa and temperature of 73°C.
[0037] In some specific embodiments, the first reduced pressure reflux extraction lasts for 60 to 90 minutes and is performed 1 to 3 times.
[0038] In some specific embodiments, the second reduced pressure reflux extraction lasts for 30 to 60 minutes and is performed 1 to 3 times.
[0039] In some specific embodiments, the tea leaves include at least one of green tea, white tea, black tea, oolong tea and dark tea.
[0040] In some specific embodiments, the tea leaves are composed of green tea, dark tea and black tea in a weight ratio of (1-2):(5-8):(1-2).
[0041] In some specific embodiments, the acidic solution is prepared by mixing malic acid, citric acid and water in a volume ratio of (5-10):(5-10):100.
[0042] In some specific embodiments, the weight ratio of the tea leaves to the acidic solution is 1:(10-15).
[0043] In some specific embodiments, the soaking time at room temperature is 12 to 24 hours.
[0044] In some specific embodiments, the Brix of the concentrated liquid tea bag is 5-50%.
[0045] It should be noted that in the preparation method of concentrated liquid tea bags provided in the embodiment of the present invention, the raw materials involved, unless otherwise specified or limited, can all be commercially available products; at the same time, the process steps and parameters involved can all be carried out according to the existing preparation process or using existing equipment in a conventional operating manner, and the present invention document will not describe them one by one.
[0046] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The experimental methods in the following examples that do not specify specific conditions are usually measured according to national standards. If there is no corresponding national standard, then the conditions recommended by the manufacturer are followed.
[0047] Example 1
[0048] This example provides a concentrated liquid tea bag, and the preparation method of the concentrated liquid tea bag comprises the following steps:
[0049] Step (1): crushing tea leaves consisting of green tea, dark tea and black tea in a weight ratio of 1.5:7:1, adding them into an acidic solution prepared by mixing malic acid, citric acid and water in a volume ratio of 7:10:100, and soaking them at room temperature for 24 hours, wherein the weight ratio of the tea leaves to the acidic solution is 1:15, to obtain a mixed liquid;
[0050] Step (2): subjecting the mixed liquid obtained in step (1) to a first reduced pressure reflux extraction at a pressure of 5 KPa, a temperature of 40° C., a time of 75 min, and a number of times of 1 time, and then filtering and separating to obtain a first extract and a first extraction residue;
[0051] Step (3): adding the acidic solution obtained in step (1) in the same volume as the first extract to the first extraction residue obtained in step (2) to carry out a second reduced pressure reflux extraction at a pressure of 30 KPa, a temperature of 73° C., a time of 45 min, and a number of times of 1, followed by filtration and separation to obtain a second extract;
[0052] Step (4): combining the first extract and the second extract and concentrating them to a Brix of 10% to obtain the concentrated liquid tea bag.
[0053] Example 2
[0054] This example provides a concentrated liquid tea bag, and the preparation method of the concentrated liquid tea bag comprises the following steps:
[0055] Step (1): crushing tea leaves consisting of green tea, dark tea and black tea in a weight ratio of 1:5:2, adding them into an acidic solution prepared by mixing malic acid, citric acid and water in a volume ratio of 5:5:100, and soaking them at room temperature for 24 hours, wherein the weight ratio of the tea leaves to the acidic solution is 1:15, to obtain a mixed liquid;
[0056] Step (2): subjecting the mixed liquid obtained in step (1) to a first reduced pressure reflux extraction at a pressure of 3 KPa, a temperature of 35° C., a time of 75 min, and a number of times of 1 time, and then filtering and separating to obtain a first extract and a first extraction residue;
[0057] Step (3): adding the acidic solution obtained in step (1) in the same volume as the first extract to the first extraction residue obtained in step (2) to carry out a second reduced pressure reflux extraction at a pressure of 26 KPa, a temperature of 65° C., a time of 45 min, and a number of times of 1, followed by filtration and separation to obtain a second extract;
[0058] Step (4): combining the first extract and the second extract and concentrating them to a Brix of 15% to obtain the concentrated liquid tea bag.
[0059] Example 3
[0060] This example provides a concentrated liquid tea bag, and the preparation method of the concentrated liquid tea bag comprises the following steps:
[0061] Step (1): crushing tea leaves consisting of green tea, dark tea and black tea in a weight ratio of 2:8:1, adding them into an acidic solution prepared by mixing malic acid, citric acid and water in a volume ratio of 10:10:100, and soaking them at room temperature for 24 hours, wherein the weight ratio of the tea leaves to the acidic solution is 1:15, to obtain a mixed liquid;
[0062] Step (2): subjecting the mixed liquid obtained in step (1) to a first reduced pressure reflux extraction at a pressure of 7 KPa, a temperature of 45° C., a time of 75 min, and a number of times of 1 time, and then filtering and separating to obtain a first extract and a first extraction residue;
[0063] Step (3): adding the acidic solution obtained in step (1) in the same volume as the first extract to the first extraction residue obtained in step (2) to carry out a second reduced pressure reflux extraction at a pressure of 35 KPa, a temperature of 77° C., a time of 45 min, and a number of times of 1 time, followed by filtration and separation to obtain a second extract;
[0064] Step (4): combining the first extract and the second extract and concentrating them to a Brix of 5% to obtain the concentrated liquid tea bag.
[0065] Comparative Example 1
[0066] This example provides a concentrated liquid tea bag and a preparation method thereof, which is different from Example 1 only in that the reduced pressure reflux extraction is adjusted to normal pressure reflux extraction; the remaining steps and parameters are the same.
[0067] This example provides a concentrated liquid tea bag, and the preparation method of the concentrated liquid tea bag comprises the following steps:
[0068] Step (1): crushing tea leaves consisting of green tea, dark tea and black tea in a weight ratio of 1.5:7:1, adding them into an acidic solution prepared by mixing malic acid, citric acid and water in a volume ratio of 7:10:100, and soaking them at room temperature for 24 hours, wherein the weight ratio of the tea leaves to the acidic solution is 1:15, to obtain a mixed liquid;
[0069] Step (2): subjecting the mixed liquid obtained in step (1) to atmospheric reflux extraction at a temperature of 105° C. for 150 min for 2 times, and then filtering and separating to obtain an extract;
[0070] Step (3): The extracts are combined and concentrated to a Brix of 10% to obtain the concentrated liquid tea bag.
[0071] Comparative Example 2
[0072] This example provides a concentrated liquid tea bag and a preparation method thereof, which is different from Example 1 only in that the acidic solution is adjusted to a conventional aqueous solution; the remaining steps and parameters are the same.
[0073] This example provides a concentrated liquid tea bag, and the preparation method of the concentrated liquid tea bag comprises the following steps:
[0074] Step (1): crushing tea leaves consisting of green tea, dark tea and black tea in a weight ratio of 1.5:7:1, adding the mixture into water and soaking the mixture at room temperature for 24 hours, wherein the weight ratio of the tea leaves to the water is 1:15, to obtain a mixed liquid;
[0075] Step (2): subjecting the mixed liquid obtained in step (1) to a first reduced pressure reflux extraction at a pressure of 5 KPa, a temperature of 40° C., a time of 75 min, and a number of times of 1 time, and then filtering and separating to obtain a first extract and a first extraction residue;
[0076] Step (3): adding the acidic solution obtained in step (1) in the same volume as the first extract to the first extraction residue obtained in step (2) to carry out a second reduced pressure reflux extraction at a pressure of 30 KPa, a temperature of 73° C., a time of 45 min, and a number of times of 1, followed by filtration and separation to obtain a second extract;
[0077] Step (4): combining the first extract and the second extract and concentrating them to a Brix of 10% to obtain the concentrated liquid tea bag.
[0078] Comparative Example 3
[0079] This example provides a concentrated liquid tea bag and a preparation method thereof, which is different from Example 1 only in that the pressure of the first reduced-pressure reflux extraction is adjusted to 12 KPa and the temperature is adjusted to 55° C.; the remaining steps and parameters are the same.
[0080] This example provides a concentrated liquid tea bag, and the preparation method of the concentrated liquid tea bag comprises the following steps:
[0081] Step (1): crushing tea leaves consisting of green tea, dark tea and black tea in a weight ratio of 1.5:7:1, adding them into an acidic solution prepared by mixing malic acid, citric acid and water in a volume ratio of 7:10:100, and soaking them at room temperature for 24 hours, wherein the weight ratio of the tea leaves to the acidic solution is 1:15, to obtain a mixed liquid;
[0082] Step (2): subjecting the mixed liquid obtained in step (1) to a first reduced pressure reflux extraction at a pressure of 12 KPa, a temperature of 55° C., a time of 75 min, and a number of times of 1 time, and then filtering and separating to obtain a first extract and a first extraction residue;
[0083] Step (3): adding the acidic solution obtained in step (1) in the same volume as the first extract to the first extraction residue obtained in step (2) to carry out a second reduced pressure reflux extraction at a pressure of 30 KPa, a temperature of 73° C., a time of 45 min, and a number of times of 1, followed by filtration and separation to obtain a second extract;
[0084] Step (4): combining the first extract and the second extract and concentrating them to a Brix of 10% to obtain the concentrated liquid tea bag.
[0085] Comparative Example 4
[0086] This example provides a concentrated liquid tea bag and a preparation method thereof, which is different from Example 1 only in that the pressure of the second reduced-pressure reflux extraction is adjusted to 12 KPa and the temperature is adjusted to 55° C.; the remaining steps and parameters are the same.
[0087] This example provides a concentrated liquid tea bag, and the preparation method of the concentrated liquid tea bag comprises the following steps:
[0088] Step (1): crushing tea leaves consisting of green tea, dark tea and black tea in a weight ratio of 1.5:7:1, adding them into an acidic solution prepared by mixing malic acid, citric acid and water in a volume ratio of 7:10:100, and soaking them at room temperature for 24 hours, wherein the weight ratio of the tea leaves to the acidic solution is 1:15, to obtain a mixed liquid;
[0089] Step (2): subjecting the mixed liquid obtained in step (1) to a first reduced pressure reflux extraction at a pressure of 5 KPa, a temperature of 40° C., a time of 75 min, and a number of times of 1 time, and then filtering and separating to obtain a first extract and a first extraction residue;
[0090] Step (3): adding the acidic solution obtained in step (1) in the same volume as the first extract to the first extraction residue obtained in step (2) to carry out a second reduced pressure reflux extraction at a pressure of 12 KPa, a temperature of 55° C., a time of 45 min, and a number of times of 1 time, followed by filtration and separation to obtain a second extract;
[0091] Step (4): combining the first extract and the second extract and concentrating them to a Brix of 10% to obtain the concentrated liquid tea bag.
[0092] Test Case
[0093] In this example, the concentrated liquid tea bags obtained in Examples 1 to 3 and Comparative Examples 1 to 4 were tested for antioxidant capacity according to the testing method disclosed in the prior art.
[0094] Test method: 1) Preparation of test sample solution: In order to better compare the antioxidant capacity of the concentrated liquid tea bags obtained, the concentrated liquid tea bags obtained in the above examples and comparative examples were uniformly concentrated to solid matter under reduced pressure in advance, and then the solid matter was prepared into a 200 mg / mL tea extract solution using anhydrous ethanol as a solvent; 2) Take ethanol solutions (25 mg·mL) containing 1 mg of tea extract of different test samples and 2 mg of DPPH -1) vortexed and mixed, reacted in a 37°C water bath for 30 minutes, and then the absorbance at 517nm was measured as Asample. At the same time, 2mL of anhydrous ethanol was mixed with 2mL of the extract to measure the absorbance value as Acontrol, and an equal amount of anhydrous ethanol was used instead of the tea sample to measure the absorbance value as Ablank, and Vc (vitamin C) was used as a positive control. According to the formula: DPPH free radical scavenging rate = [1-(Asample-Acontrol / Ablank)] × 100%, Asample represents the absorbance value of the sample (tea extract and DPPH ethanol solution), Ablank represents the absorbance value of the blank sample (tea extract and ethanol), and Acontrol represents the absorbance value of the control group (ethanol and DPPH ethanol solution); the DPPH free radical scavenging rate (%) of each group of test samples was calculated, and the test results are shown in Table 1.
[0095] Table 1
[0096]
[0097]
[0098] It can be seen from Table 1 that, compared with the comparative example, the concentrated liquid tea bag provided by the embodiment of the present invention has a higher DPPH radical scavenging rate, and the DPPH radical scavenging rate of Example 1 is the highest, which can reach 81.6%, indicating that the concentrated liquid tea bag provided by the embodiment of the present invention has better antioxidant capacity.
[0099] In summary, the embodiment of the present invention provides a method for preparing a concentrated liquid tea bag. By using a weakly acidic solution as an extraction solvent and coordinating a reduced pressure reflux extraction method under specific parameters, and by selecting specific extraction conditions and solvents, the destruction of active ingredients in tea leaves by factors such as high temperature, high pressure and oxidation is effectively avoided. The use of an acidic solution also helps to protect the active ingredients from being affected by enzymatic hydrolysis. The reduced pressure reflux extraction technology reduces the boiling point of the solvent, so that efficient extraction can be achieved at a lower temperature, effectively avoiding the destruction of active ingredients in tea leaves. At the same time, two extractions under different conditions can extract active ingredients of different properties in tea leaves respectively, which improves the comprehensiveness and efficiency of the extraction, and significantly improves the antioxidant capacity of the obtained concentrated liquid tea bag, thereby enhancing its health care effect and making up for the shortcomings of the prior art.
[0100] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.
[0101] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.
Claims
1. A method for preparing a concentrated liquid tea bag, characterized in that: The preparation method of the concentrated liquid tea bag comprises the following steps: The tea leaves are crushed, and then added into an acidic solution for soaking at room temperature to obtain a mixed liquid; The mixed liquid is subjected to a first decompression reflux extraction, and then filtered and separated to obtain a first extract and a first extraction residue; Performing a second reduced-pressure reflux extraction on the first extraction residue to obtain a second extract; combining and concentrating the first extract and the second extract to obtain the concentrated liquid tea bag; Among them, the working condition parameters of the first reduced pressure reflux extraction include: pressure of 3~7KPa, temperature of 35~45℃; the working condition parameters of the second reduced pressure reflux extraction include: pressure of 26~35KPa, temperature of 65~77℃.
2. The method for preparing a concentrated liquid tea bag according to claim 1, characterized in that: The working condition parameters of the first reduced pressure reflux extraction include: pressure of 5 KPa and temperature of 40°C; the working condition parameters of the second reduced pressure reflux extraction include: pressure of 30 KPa and temperature of 73°C.
3. The method for preparing concentrated liquid tea bag according to claim 1, characterized in that: The first decompression reflux extraction takes 60 to 90 minutes and is performed 1 to 3 times.
4. The method for preparing concentrated liquid tea bag according to claim 1, characterized in that: The second reduced pressure reflux extraction takes 30 to 60 minutes and is performed 1 to 3 times.
5. The method for preparing concentrated liquid tea bag according to claim 1, characterized in that: The tea leaves include at least one of green tea, white tea, black tea, oolong tea and dark tea.
6. The method for preparing concentrated liquid tea bag according to claim 1, characterized in that: The tea leaves are composed of green tea, dark tea and black tea in a weight ratio of (1-2):(5-8):(1-2).
7. The method for preparing concentrated liquid tea bag according to claim 1, characterized in that: The acidic solution is prepared by compounding malic acid, citric acid and water in a volume ratio of (5-10):(5-10):
100.
8. The method for preparing concentrated liquid tea bag according to claim 1, characterized in that: The weight ratio of the tea leaves to the acidic solution is 1:(10-15).
9. The method for preparing concentrated liquid tea bag according to claim 1, characterized in that: The soaking time at room temperature is 12 to 24 hours.
10. The method for preparing concentrated liquid tea bag according to claim 1, characterized in that: The Brix of the concentrated liquid tea bag is 5-50%.