Precipitation device for extracting tea protein and process for extracting tea protein using the same

Abstract

The present application relates to the technical field of tea processing, in particular to a precipitating device for extracting tea protein and a process for extracting tea protein using the same, which sequentially performs extraction, ceramic membrane and rolling membrane immersion, filtration treatment and centrifugal separation treatment, and can simplify the production process, reduce the production cost and improve the production efficiency; compared with the process method of the prior art using membrane filtration, ultrafiltration and chromatography, the required equipment and operation process steps are simpler, the cost is lower, the production cycle is shorter, and the production efficiency is improved.

Description

Technical Field

[0001] This invention relates to the field of tea processing technology, specifically to a precipitation device for extracting tea protein and a process for extracting tea protein using the same device. Background Technology

[0002] my country is a major consumer of tea, with domestic sales reaching millions of tons annually. The production of tea polyphenols, tea beverages, and instant tea generates a large amount of residue each year, much of which still retains significant nutritional components. A major component of tea residue is tea protein, which can reach up to 20%, primarily composed of gluten and alcohol-soluble proteins. Tea protein plays a positive role in lowering blood lipids, anti-oxidation, scavenging free radicals, and radiation protection, attracting increasing attention from researchers. Studies have been conducted on the extraction, purification, and characteristics of tea protein from tea residue, and some literature reports have documented these findings.

[0003] Currently, the main extraction methods for tea proteins include alkaline extraction, enzymatic hydrolysis, and combined extraction. Alkaline extraction is relatively simple and suitable for industrial production, but the large amount of alkaline substances used can damage the tea proteins, resulting in low extraction efficiency and environmental pollution. Enzymatic hydrolysis preserves various bioactive peptides in the extracted tea proteins, making it more widely applicable; however, this method has lower extraction efficiency and relatively higher costs. Combined extraction typically uses multiple methods in combination to leverage their respective advantages. This method can achieve a high protein extraction rate, but its process is more complex and difficult to implement industrially.

[0004] Therefore, considering the advantages and disadvantages of existing tea protein extraction processes, a solution is needed to address the technical problems present in the current technology. Summary of the Invention

[0005] This invention provides a precipitation device for extracting tea protein and a process for extracting tea protein using the same device, which can at least solve some of the problems existing in the prior art.

[0006] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0007] A precipitation apparatus for extracting tea protein, wherein the precipitation apparatus includes a diluent tank and at least two precipitation tanks arranged in parallel;

[0008] The sedimentation tank has three inlets arranged side by side at the top, an observation window in the middle, and a conical structure at the bottom, with a three-valve structure at the bottom of the conical structure.

[0009] The diluent tank is equipped with a double valve structure at the bottom. The diluent tank and the sedimentation tank are connected by a pipeline, which is equipped with a valve, a one-way metering pump and a flow meter.

[0010] As a preferred embodiment of the precipitation device for extracting tea protein according to the present invention, the three inlets arranged side by side on the top of the precipitation tank are respectively used to inject a first retentate, a diluent, and a washing water into the precipitation tank.

[0011] As a preferred embodiment of the precipitation device for extracting tea protein according to the present invention, the three-valve structure is used to discharge the supernatant, precipitate and residual wastewater respectively.

[0012] As a preferred embodiment of the precipitation device for extracting tea protein according to the present invention, the precipitation tank is configured as three, the height of the three precipitation tanks is 2300-2500mm, two of the precipitation tanks have a diameter of 400-600mm, and the diameter of the other precipitation tank is 600-800mm.

[0013] To solve the above-mentioned technical problems, according to another aspect of the present invention, the present invention provides the following technical solution:

[0014] A process for extracting tea protein using the above-mentioned precipitation device includes the following steps:

[0015] Step 1: Rinse the black tea leaves with water;

[0016] Step 2: Place the black tea leaves into the extraction tank, pour in distilled water, and soak them under high temperature and high pressure to obtain the extract.

[0017] Step 3: The obtained extract is filtered using a ceramic membrane to obtain a primary filtrate and a retentate. The retentate is used to produce tea powder.

[0018] Step 4: The obtained primary filtrate is filtered using a roll-up membrane to obtain a first retentate and a secondary filtrate. The secondary filtrate is discharged through the wastewater discharge channel.

[0019] Step 5: The first retentate is sent to a sedimentation tank for dilution and precipitation to obtain supernatant and precipitate. The precipitate is then centrifuged to obtain tea protein.

[0020] Step 6: The obtained supernatant is subjected to secondary filtration using a roll-up membrane to obtain a second retentate. Dextrin is added to the second retentate, and the mixture is spray-dried to obtain tea glycoside granules.

[0021] As a preferred embodiment of the tea protein extraction process of the present invention, the ceramic membrane in step 3 has a pore size of 50-80 nanometers, and the roll membrane in step 4 has a pore size of 4000-7000 Daltons.

[0022] As a preferred embodiment of the tea protein extraction process of the present invention, the specific operation steps of step 5 are as follows: the diluent is quickly injected into the sedimentation tank, the injection time is not more than 2 minutes, and after injection, the sedimentation is allowed to stand for 1-3 hours.

[0023] In a preferred embodiment of the process for extracting tea protein according to the present invention, after the diluent is injected into the sedimentation tank, the ratio of the height of the liquid after the first retentate and the diluent are mixed to the diameter of the sedimentation tank is at least 1.5.

[0024] As a preferred embodiment of the process for extracting tea protein according to the present invention, the centrifugal separation speed is 1000-4000 r / min.

[0025] As a preferred embodiment of the tea protein extraction process of the present invention, the diluent is a dilute acid solution of acetic acid, gluconic acid, malic acid or citric acid, the mass concentration of the acid in the diluent is 2-5%, and the mass ratio of the injected amount of the diluent to the mass of the first retentate is (0.7-1.0):1.

[0026] The beneficial effects of this invention are as follows:

[0027] 1. The processing technology for black tea protein of the present invention uses only ceramic membrane and spiral wound membrane filtration devices for filtration. The retentate obtained after filtration is diluted and precipitated to obtain a precipitate. The precipitate is then centrifuged to obtain the tea protein. Compared with the alkaline method, enzymatic hydrolysis method, and composite method in the prior art, the tea protein processing method of the present invention can ensure production efficiency and extraction yield, while not using alkaline substances and causing no environmental pollution. Compared with the existing processes using membrane filtration, ultrafiltration, and chromatography, the required equipment and operating steps are simpler, the cost is lower, the production cycle is shorter, and the production efficiency is improved.

[0028] 2. The extraction and dilution precipitation processes of this invention do not use organic solvents for processing, so there are no organic solvent residues, which improves the food safety level.

[0029] 3. The diluent used in the dilution and precipitation process of this invention is a food-grade acidic solvent such as tartaric acid, malic acid, citric acid, and acetic acid, which improves the extraction efficiency of tea extract. The extracted tea extract product has a fruity aroma, better taste, and is more likely to be favored by consumers. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the process for extracting tea protein according to the present invention;

[0032] Figure 2 This is the precipitation device used in the embodiments of the present invention;

[0033] Figure 3 The sedimentation tank used in the embodiments of the present invention;

[0034] Figure 4 This is the dilution tank used in an embodiment of the present invention.

[0035] Explanation of icon numbers:

[0036] 1-Sedimentation tank No. 1, 2-Sedimentation tank No. 2, 3-Sedimentation tank No. 3, 4-Dilution tank, 5-First retentate inlet, 6-Diluent inlet, 7-Washing water inlet, 8-Flow meter, 9-One-way metering pump.

[0037] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0038] The technical solutions described below in conjunction with the embodiments will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0040] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0041] This invention provides a precipitation device for extracting tea protein and a process for extracting tea protein using the device. The process involves sequential extraction, immersion in a ceramic membrane and a rolled membrane, filtration, and centrifugation, which simplifies the production process, reduces production costs, and improves production efficiency.

[0042] A precipitation apparatus for extracting tea protein, wherein the precipitation apparatus includes a diluent tank and at least two precipitation tanks arranged in parallel;

[0043] The sedimentation tank has three inlets arranged side by side at the top, an observation window in the middle, and a conical structure at the bottom, with a three-valve structure at the bottom of the conical structure.

[0044] The diluent tank is equipped with a double valve structure at the bottom. The diluent tank and the sedimentation tank are connected by a pipeline, which is equipped with a valve, a one-way metering pump and a flow meter.

[0045] Preferably, the three inlets arranged side by side on the top of the sedimentation tank are used to inject the first retentate, diluent, and washing water into the sedimentation tank, respectively.

[0046] Preferably, the three-valve structure is used to discharge the supernatant, sediment, and residual wastewater, respectively.

[0047] Preferably, there are three sedimentation tanks, with a height of 2300-2500mm, two of which have a diameter of 400-600mm and the other has a diameter of 600-800mm.

[0048] The number of settling tanks can be adjusted according to production output needs. Similarly, the specifications and dimensions of the settling tanks can also be changed according to production output to improve production efficiency and make effective use of the settling tank volume. An example is given below.

[0049] To solve the above-mentioned technical problems, according to another aspect of the present invention, the present invention provides the following technical solution:

[0050] A process for extracting tea protein using the above-mentioned precipitation device includes the following steps:

[0051] Step 1: Rinse the black tea leaves with water;

[0052] Step 2: Place the black tea leaves into the extraction tank, pour in distilled water, and soak them under high temperature and high pressure to obtain the extract.

[0053] Step 3: The obtained extract is filtered using a ceramic membrane to obtain a primary filtrate and a retentate. The retentate is used to produce tea powder.

[0054] Ceramic membrane filtration can remove fiber particles from tea leaves;

[0055] Step 4: The obtained primary filtrate is filtered using a roll-up membrane to obtain a first retentate and a secondary filtrate. The secondary filtrate is discharged through the wastewater discharge channel.

[0056] Film coating can remove tannins and other small molecules from tea leaves;

[0057] Step 5: The first retentate is sent to a sedimentation tank for dilution and precipitation to obtain supernatant and precipitate. The precipitate is then centrifuged to obtain tea protein.

[0058] Adding a diluent can remove impurities from the retentate, resulting in a supernatant component with higher purity;

[0059] Step 6: The obtained supernatant is subjected to secondary filtration using a roll-up membrane to obtain a second retentate. Dextrin is added to the second retentate, and the mixture is spray-dried to obtain tea glycoside granules.

[0060] Preferably, the ceramic membrane in step 3 has a pore size of 50-80 nanometers, and the rolled membrane in step 4 has a pore size of 4000-7000 Daltons.

[0061] Preferably, the specific operation steps of step 5 are as follows: the diluent is quickly injected into the sedimentation tank, the injection time is not more than 2 minutes, and after injection, the sedimentation is allowed to stand for 1-3 hours.

[0062] The diluent needs to be injected from the top of the settling tank to ensure that it is fully and evenly mixed with the first retentate.

[0063] The diluent injection time should not exceed 2 minutes. If it exceeds 2 minutes, it will disrupt the reaction process between the diluent and the first retentate, causing impurities that cannot precipitate or have already begun to precipitate to be dispersed by the diluent injected from a higher position, affecting the precipitation effect and efficiency.

[0064] Tea proteins are difficult to complex and precipitate under agitation conditions; therefore, the diluent should not be agitated during injection.

[0065] After the diluent is injected, allow it to stand and settle for 1-3 hours. If the time is too short, the sedimentation will be incomplete; if the time is too long, a complex precipitate of tea polysaccharides and theabrownins may easily form.

[0066] Preferably, after the diluent is injected into the settling tank, the ratio of the height of the liquid after the first retentate and the diluent are mixed to the diameter of the settling tank is at least 1.5.

[0067] The bottom of the sedimentation tank is designed with a conical structure, which facilitates the discharge of sediment and residual wastewater. The liquid level after the first retentate and diluent are mixed should be more than 1.5 times the diameter of the tank. If this ratio is less than 1.5, it will lead to no sedimentation or insufficient sedimentation, which is not conducive to the extraction of tea glycosides.

[0068] For example, if the first retentate produced each day is 400 kg, 300 kg of diluent is needed, totaling approximately 0.7 m³. 3 Liquid (based on 1000 kg / m³) 3 (Calculation) Assuming we have two sedimentation tanks with a diameter of 700mm and a height of 1650mm, and one with a diameter of 500mm and a height of 1650mm, the 700mm sedimentation tank can hold a maximum of 0.635m³. 3 The liquid (formula V = π(r)) 2 A 500mm sedimentation tank can hold a maximum of 0.324m³. 3 The liquid (formula V = π(r)) 2 (h). Based on the following calculation: 0.635m 3 +0.324m 3 =0.959m 3 >0.7m 3 0.324m 3 +0.324m 3 =0.648m 3 <1m 3 Therefore, a 700mm and a 500mm sedimentation tank are selected to hold the first retentate. Since the liquid level after adding the first retentate and diluent should not be less than 1.5 times the tank diameter, the 700mm sedimentation tank should hold at least 231kg ​​of the first retentate and 173kg of diluent (at this point, the liquid weight is 0.404m). 3 The liquid level should be ≥1050mm. A 500mm sedimentation tank should contain at least 85kg of the first retentate and 63kg of diluent (at this point, the liquid weight is 0.148m). 3The liquid level is 754mm (≥750mm), and the remaining 85kg of the first retentate and 63kg of diluent (the remaining liquid weight is 0.148m) are present. 3 It can be poured into any sedimentation tank of 700mm or 500mm or distributed evenly, etc.

[0069] Preferably, the centrifugal separation process is carried out at a speed of 1000-4000 r / min.

[0070] Preferably, the diluent is a dilute acid solution of acetic acid, gluconic acid, malic acid, or citric acid.

[0071] Preferably, the mass concentration of acid in the diluent is 2-5%, and the mass ratio of the injected diluent to the first retentate is (0.7-1.0):1.

[0072] Example 1

[0073] The following is in conjunction with the appendix Figure 2-4 The precipitation device used in this invention will be illustrated by example.

[0074] A precipitation device for extracting tea protein, comprising a diluent tank 4 and three precipitation tanks arranged in parallel, namely precipitation tank No. 1, precipitation tank No. 2 and precipitation tank No. 3.

[0075] Settling tank No. 1 and settling tank No. 2 have the same specifications and dimensions. The height of settling tank No. 1 from the ground to the top is 2300mm and the diameter is 700mm. Settling tank No. 3 has the same height of 2300mm from the ground to the top and the diameter is 500mm.

[0076] The sedimentation tank has three inlets arranged side by side at the top and an observation window in the middle. The bottom of the sedimentation tank has a conical structure with a three-valve structure at the bottom. The three valves are used to discharge the supernatant, sediment and residual wastewater respectively.

[0077] The bottom of the diluent tank is equipped with a double valve structure. One valve at the bottom of the diluent tank 4 is connected to the sedimentation tank through a pipeline, which is used to inject the diluent solution into the sedimentation tank. The pipeline is equipped with a valve, a one-way metering pump and a flow meter.

[0078] The three inlets arranged side by side at the top of the settling tank are used to inject the first retentate, diluent, and washing water into the settling tank, respectively.

[0079] Example 2

[0080] The following is in conjunction with the appendix Figure 1 The extraction and processing technology of tea protein in this invention will be illustrated by example.

[0081] A process for extracting and preparing tea protein includes the following steps:

[0082] Step 1: Take 1000g of Ceylon black tea as raw material, sieve to remove excessively fine tea powder, wash the black tea leaves with water to obtain short strips of tea leaves.

[0083] Step 2: Place the pretreated black tea leaves into an extraction tank, add distilled water, and soak the tea leaves under high temperature and high pressure to obtain an extract. The ratio of distilled water to tea leaves is 30 mL: 1 g. The extraction and soaking temperature is 80℃, and the soaking time is 4 hours.

[0084] Step 3: The obtained extract is filtered using a ceramic membrane to obtain a primary filtrate and a retentate. The retentate is used to produce tea powder. The ceramic membrane has a pore size of 60 nanometers.

[0085] Step 4: The obtained primary filtrate is filtered using a roll-up membrane to obtain a first retentate and a secondary filtrate. The secondary filtrate is discharged through the wastewater discharge channel. The pore size of the roll-up membrane is 6000 Daltons.

[0086] Step 5: The first retentate is sent to a sedimentation tank for dilution and precipitation. The dilution and precipitation are performed using the sedimentation device shown in Example 1. After dilution and precipitation, a supernatant and precipitate are obtained. The precipitate is used to produce tea powder. The diluent is a citric acid solution with a concentration of 3 wt%. The mass ratio of the diluent to the first retentate is 0.8:1, and the diluent is injected over 2 minutes. After injection, the precipitate is allowed to stand for 2 hours to settle. The precipitate is then centrifuged to obtain tea protein. The centrifugation speed is 3000 r / min, and the weight of the tea protein obtained by centrifugation is 65.4 g.

[0087] Step 6: The obtained supernatant is subjected to secondary filtration using a roll-up membrane to obtain a second retentate. Dextrin is added to the second retentate, and the mixture is spray-dried to obtain tea glycoside granules.

[0088] Example 3

[0089] A process for extracting and preparing tea protein includes the following steps: Step 1: Take 1000g of Ceylon black tea as raw material, sieve to remove excessively fine tea powder, and wash the black tea leaves with water to obtain short strip tea leaves.

[0090] Step 2: Place the pretreated black tea leaves into an extraction tank, add distilled water, and soak the tea leaves under high temperature and high pressure to obtain an extract. The ratio of distilled water to tea leaves is 30 mL: 1 g. The extraction and soaking temperature is 90℃, and the soaking time is 3.5 h.

[0091] Step 3: The obtained extract is filtered using a ceramic membrane to obtain a primary filtrate and a retentate. The retentate is used to produce tea powder. The ceramic membrane has a pore size of 50 nanometers.

[0092] Step 4: The obtained primary filtrate is filtered using a roll-up membrane to obtain a first retentate and a secondary filtrate. The secondary filtrate is discharged through the wastewater discharge channel. The pore size of the roll-up membrane is 4000 Daltons.

[0093] Step 5: The first retentate is sent to a sedimentation tank for dilution and precipitation. The dilution and precipitation are performed using the sedimentation device shown in Example 1. After dilution and precipitation, a supernatant and precipitate are obtained. The precipitate is used to produce tea powder. The diluent is an acetic acid solution with a concentration of 4 wt%. The mass ratio of the diluent to the first retentate is 1:1, and the diluent is injected over 2 minutes. After injection, the precipitate is allowed to stand for 3 hours to settle. The precipitate is then centrifuged to obtain tea protein. The centrifugation speed is 2000 r / min, and the weight of the tea protein obtained by centrifugation is 64.8 g.

[0094] Step 6: The obtained supernatant is subjected to secondary filtration using a roll-up membrane to obtain a second retentate. Dextrin is added to the second retentate, and the mixture is spray-dried to obtain tea glycoside granules.

[0095] Example 4

[0096] A process for extracting and preparing tea protein includes the following steps:

[0097] Step 1: Take 1000g of Ceylon black tea as raw material, sieve to remove excessively fine tea powder, wash the black tea leaves with water to obtain short strips of tea leaves.

[0098] Step 2: Place the pretreated black tea leaves into an extraction tank, add distilled water, and soak the tea leaves under high temperature and high pressure to obtain an extract. The ratio of distilled water to tea leaves is 30 mL: 1 g. The extraction and soaking temperature is 80℃, and the soaking time is 4 hours.

[0099] Step 3: The obtained extract is filtered using a ceramic membrane to obtain a primary filtrate and a retentate. The retentate is used to produce tea powder. The ceramic membrane has a pore size of 80 nanometers.

[0100] Step 4: The obtained primary filtrate is filtered using a roll-up membrane to obtain a first retentate and a secondary filtrate. The secondary filtrate is discharged through the wastewater discharge channel. The pore size of the roll-up membrane is 7000 Daltons.

[0101] Step 5: The first retentate is sent to a sedimentation tank for dilution and precipitation. The dilution and precipitation are performed using the sedimentation device shown in Example 1. After dilution and precipitation, a supernatant and precipitate are obtained. The precipitate is used to produce tea powder. The diluent is a malic acid solution with a concentration of 2 wt%. The mass ratio of the diluent to the first retentate is 0.7:1, and the diluent is injected over 2 minutes. After injection, the precipitate is allowed to stand for 1 hour to settle. The precipitate is then centrifuged to obtain tea protein. The centrifugation speed is 4000 r / min, and the weight of the tea protein obtained by centrifugation is 69.5 g.

[0102] Step 6: The obtained supernatant is subjected to secondary filtration using a roll-up membrane to obtain a second retentate. Dextrin is added to the second retentate, and the mixture is spray-dried to obtain tea glycoside granules.

[0103] Example 5

[0104] A process for extracting and preparing tea protein includes the following steps:

[0105] Step 1: Take 1000g of Ceylon black tea as raw material, sieve to remove excessively fine tea powder, wash the black tea leaves with water to obtain short strips of tea leaves.

[0106] Step 2: Place the pretreated black tea leaves into an extraction tank, add distilled water, and soak the tea leaves under high temperature and high pressure to obtain an extract. The ratio of distilled water to tea leaves is 30 mL: 1 g. The extraction and soaking temperature is 90℃, and the soaking time is 3 hours.

[0107] Step 3: The obtained extract is filtered using a ceramic membrane to obtain a primary filtrate and a retentate. The retentate is used to produce tea powder. The ceramic membrane has a pore size of 70 nanometers.

[0108] Step 4: The obtained primary filtrate is filtered using a roll-up membrane to obtain a first retentate and a secondary filtrate. The secondary filtrate is discharged through the wastewater discharge channel. The pore size of the roll-up membrane is 5000 Daltons.

[0109] Step 5: The first retentate is sent to a sedimentation tank for dilution and precipitation. The dilution and precipitation are performed using the sedimentation device shown in Example 1. After dilution and precipitation, a supernatant and precipitate are obtained. The precipitate is used to produce tea powder. The diluent is a 5 wt% glucose solution. The mass ratio of the diluent to the first retentate is 0.9:1, and the diluent is injected over 2 minutes. After injection, the precipitate is allowed to stand for 3 hours to settle. The precipitate is then centrifuged to obtain tea protein. The centrifugation speed is 2000 r / min, and the weight of the tea protein obtained by centrifugation is 65.1 g.

[0110] Step 6: The obtained supernatant is subjected to secondary filtration using a roll-up membrane to obtain a second retentate. Dextrin is added to the second retentate and spray-dried to obtain tea granules.

[0111] Example 6

[0112] A process for extracting and preparing tea protein includes the following steps:

[0113] Step 1: Take 1000g of Ceylon black tea as raw material, sieve to remove excessively fine tea powder, wash the black tea leaves with water to obtain short strips of tea leaves.

[0114] Step 2: Place the pretreated black tea leaves into an extraction tank, add distilled water, and soak the tea leaves under high temperature and high pressure to obtain an extract. The ratio of distilled water to tea leaves is 30 mL: 1 g. The extraction and soaking temperature is 90℃, and the soaking time is 4 hours.

[0115] Step 3: The obtained extract is filtered using a ceramic membrane to obtain a primary filtrate and a retentate. The retentate is used to produce tea powder. The ceramic membrane has a pore size of 50 nanometers.

[0116] Step 4: The obtained primary filtrate is filtered using a roll-up membrane to obtain a first retentate and a secondary filtrate. The secondary filtrate is discharged through the wastewater discharge channel. The pore size of the roll-up membrane is 6000 Daltons.

[0117] Step 5: The first retentate is sent to a sedimentation tank for dilution and precipitation. The dilution and precipitation are performed using the sedimentation device shown in Example 1. After dilution and precipitation, a supernatant and precipitate are obtained. The precipitate is used to produce tea powder. The diluent is a mixed solution of malic acid and citric acid, with a weight ratio of malic acid to citric acid of 1:1 and an acid concentration of 3wt%. The mass ratio of the diluent injection to the first retentate is 0.8:1, and the diluent injection time is 2 minutes. After injection, the solution is allowed to stand for 2 hours for precipitation. The precipitate is then centrifuged to obtain tea protein. The centrifugation speed is 3000 r / min, and the weight of the tea protein obtained by centrifugation is 68.9 g.

[0118] Step 6: The obtained supernatant is subjected to secondary filtration using a roll-up membrane to obtain a second retentate. Dextrin is added to the second retentate and spray-dried to obtain tea glycoside granules.

[0119] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A process for extracting tea protein and tea-derived element particles, characterized in that, This process uses only two filtration methods: ceramic membranes and spiral wound membranes. It does not include a chromatography filtration step and includes the following steps: Step 1: Rinse the black tea leaves with water; Step 2: Place the black tea leaves into the extraction tank, pour in distilled water, and soak them under high temperature and high pressure to obtain the extract. Step 3: The obtained extract is filtered using a ceramic membrane to obtain a primary filtrate and a retentate. The retentate is used to produce tea powder. The pore size of the ceramic membrane is 50-80 nanometers. Step 4: The obtained primary filtrate is filtered using a roll-up membrane to obtain a first retentate and a secondary filtrate. The secondary filtrate is discharged through the wastewater discharge channel. The pore size of the roll-up membrane is 4000-7000 Daltons. Step 5: The first retentate is sent to a sedimentation tank for dilution and precipitation to obtain a supernatant and precipitate. The precipitate is centrifuged to obtain tea protein. The centrifugation speed is 1000-4000 r / min. The specific operation steps are as follows: the diluent is quickly injected into the sedimentation tank for no more than 2 minutes. After injection, the sedimentation is allowed to stand for 1-3 hours. The diluent is a food-grade dilute acid solution of acetic acid, gluconic acid, malic acid or citric acid. The mass concentration of the acid in the diluent is 2-5%. The mass ratio of the injected diluent to the first retentate is (0.7-1.0):

1. After the diluent is injected into the sedimentation tank, the height of the liquid after mixing the first retentate and the diluent is at least 1.5 times the diameter of the sedimentation tank. Step 6: The obtained supernatant is subjected to secondary filtration using a roll-up membrane to obtain a second retentate. Dextrin is added to the second retentate, and the mixture is spray-dried to obtain tea extract granules. The extraction process employs a sedimentation device comprising a diluent tank and at least two sedimentation tanks arranged in parallel. The sedimentation tank has three inlets arranged side-by-side at its top, an observation window in the middle, and a conical bottom with a three-valve structure. The diluent tank has a double-valve structure at its bottom. The diluent tank and sedimentation tanks are connected by a pipeline equipped with valves, a one-way metering pump, and a flow meter. The three inlets at the top of the sedimentation tank are used to inject the first retentate, diluent, and washing water into the sedimentation tank, respectively. The three-valve structure is used to discharge the supernatant, precipitate, and residual wastewater, respectively. Three sedimentation tanks are configured, each with a height of 2300-2500 mm. Two of the sedimentation tanks have a diameter of 400-600 mm, and the third sedimentation tank has a diameter of 600-800 mm.

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