A preparation and purification process of tea seed polypeptide

Abstract

The invention discloses a preparation and purification process of tea seed polypeptide, which comprises the following steps: firstly crushing tea seed meal and then soaking it with water, then adjusting the pH value to 10-12 with an alkaline solution, treating it in a water bath at 35 to 55°C for 90-120 minutes, and stirring to dissolve the protein. After centrifugation, a tea seed crude protein solution is obtained, which is then treated with an acidic solution to maintain a pH value of 4.5-5.5, and is also treated in a water bath at a temperature of 90-120 minutes. After solid-liquid separation, the solution is washed to neutrality, and freeze-dried and crushed to obtain tea tree seed protein powder, which is mixed with an enzyme preparation, and the pH value and temperature are adjusted to perform enzymolysis reaction for 2-4 hours. After heating and inactivating the enzyme, the solution is centrifuged to obtain a solution containing the target tea seed polypeptide, and then purified by ultrafiltration membrane, ion exchange chromatography and gel permeation chromatography in sequence to ensure uniform molecular weight distribution, and finally concentrated and dried to obtain tea seed polypeptide powder. The invention not only improves the utilization rate of resources, but also provides the possibility for the wide application of tea seed polypeptide, and has significant social and economic benefits.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of polypeptide components, and in particular to a preparation and purification process of tea seed polypeptide. Background Art

[0002] At present, most of the camellia oleifera meal is used as organic fertilizer, fuel or animal feed after detoxification. Its development and utilization are low, and its added value is low, resulting in a large waste of resources. Therefore, it is particularly important to study the comprehensive processing and utilization of camellia oleifera meal.

[0003] The main components of camellia oleifera seed meal are fat and protein. Its protein content is between 10% and 15%. It contains 17 kinds of amino acids, including 8 essential amino acids for the human body, which makes it a high-quality protein resource with significant utilization potential. By hydrolyzing these proteins with acid, alkali or enzyme, polypeptide substances with high biological activity can be obtained. These polypeptides are not only of high nutritional value and helpful for digestion and absorption, but also show a wide range of biological activities. They are essential for maintaining the normal physiological functions of the human nervous system, digestive system, reproductive system, growth, movement, metabolism, circulation and other systems. They have multiple functions such as immune regulation, hormone regulation, antiviral, antibacterial, antioxidant, blood pressure reduction, blood lipid reduction, cholesterol reduction, etc., and have broad application prospects in the research and development of functional foods and sports foods. Based on the above reasons, preparing proteins in camellia oleifera seed meal into active polypeptides can provide a new way for the development and utilization of camellia oleifera seed meal protein resources.

[0004] At present, the effective ways to convert the protein in camellia oleifera seed meal into active peptides mainly include chemical hydrolysis, enzymatic hydrolysis and microbial fermentation. Among these methods, enzymatic hydrolysis has become the mainstream technology for the preparation of camellia oleifera seed peptides due to its mildness and high efficiency. This method uses the high specificity of enzymes to not only improve reaction efficiency and shorten hydrolysis time, but also accurately control the degree of hydrolysis, making the product easy to separate, which is very suitable for meeting the needs of industrial production.

[0005] However, as the study of enzymatic hydrolysis has deepened, its limitations have gradually become apparent. For example, enzymatic hydrolysis requires the extraction of protein from the raw materials first, and this extraction process is relatively complicated; then, the extracted protein needs to be converted into peptides through enzymatic hydrolysis, and the cost of enzyme preparations is high, which leads to an increase in production costs. In addition, this method cannot completely remove anti-nutritional factors in the raw materials.

[0006] Based on the above reasons, it is necessary to develop a more efficient, lower-cost tea seed polypeptide preparation and purification process that can effectively remove anti-nutritional factors. Summary of the invention

[0007] The technical problem solved by the present invention is to provide a preparation and purification process of tea seed polypeptide, which can be used to solve the defects in the above technical background.

[0008] The technical problem solved by the present invention is achieved by adopting the following technical solutions:

[0009] A process for preparing and purifying tea seed polypeptides, wherein the process uses tea seed meal as a raw material to prepare and purify tea seed polypeptides, and comprises the following steps:

[0010] S1. Crush the camellia oleifera seed meal, put the crushed pieces into a container, and soak them with clean water. After the soaking is completed, adjust the pH value of the soaking solution to alkaline using an alkaline solution, and keep the pH value of the alkaline soaking solution at 10 to 12; then keep the container in a water bath, and treat it at a temperature of 35 to 55° C. for 90 to 120 minutes, during which stirring is maintained to dissolve the protein in the camellia oleifera seed meal; then remove insoluble impurities by centrifugation to obtain a camellia seed crude protein solution;

[0011] S2, soaking the extracted tea seed crude protein solution in an acidic soaking solution, maintaining the pH value of the acidic soaking solution at 4.5 to 5.5, then keeping the container in a water bath at a temperature of 35 to 55° C. for 90 to 120 minutes, separating the solid from the liquid to obtain a solid, and washing with running water until neutral; then freeze-drying the solid and crushing it to obtain tea seed protein powder;

[0012] S3, using the tea tree seed protein powder obtained in step S2 as a raw material, mixing the tea tree seed protein powder with an enzyme preparation, adjusting the pH value and the reaction temperature to the optimal action range of the enzyme, the enzymatic reaction time is 2 to 4 hours, and stirring is continued during the enzymatic hydrolysis process. After the enzymatic hydrolysis is completed, the enzyme is inactivated by heating, and then the unreacted protein powder and enzyme preparation are removed by centrifugation, and the obtained supernatant is a solution containing the target tea seed polypeptide;

[0013] S4, purifying the tea seed polypeptide solution obtained in step S3, the specific operation sequence is:

[0014] The tea seed polypeptide solution is initially separated through an ultrafiltration membrane to remove macromolecular impurities;

[0015] Ion exchange chromatography was used for further purification, using ion exchange resins to adsorb and elute the tea seed polypeptides according to their charge characteristics;

[0016] Gel permeation chromatography is used to remove the remaining small molecule impurities to ensure uniform molecular weight distribution of tea seed polypeptides;

[0017] S5. Concentrating the purified tea seed polypeptide solution and drying it to obtain a purified finished tea seed polypeptide powder.

[0018] As a further limitation, in step S1, the camellia oleifera meal as the raw material is pre-defatted, and the specific defatting operation method is as follows:

[0019] The camellia oleifera seed meal is crushed to a particle size of less than 3 mm, and then an organic solvent is used for impregnation treatment, and the duration of the impregnation treatment is controlled to be 30 to 90 minutes. After that, the solvent is removed by centrifugation to obtain defatted camellia oleifera seed meal; the defatted camellia oleifera seed meal is then washed with water to remove the residual organic solvent, and the defatted camellia oleifera seed meal is dried to reduce the moisture content to less than 5%, thereby completing the defatting treatment of the camellia oleifera seed meal;

[0020] The organic solvent is preferably n-hexane, and the organic solvent soaking process is carried out in 3 to 5 times, with a single soaking treatment time of 30 to 90 minutes. After completing the above degreasing step, the degreasing rate of camellia oleifera meal can reach more than 85%.

[0021] As a further limitation, in step S1, the camellia seed meal is crushed according to the type of camellia seed meal before being crushed: for the camellia seed meal obtained by the pressing process, the particle size after crushing after airing or drying is less than 3 mm; for the camellia seed meal obtained by the leaching process, since its particle size is finer, the particle size after crushing after airing or drying is less than 1 mm.

[0022] As a further limitation, the alkaline solution used in step S1 is preferably a NaOH solution, and the acidic soaking solution used in step S2 is preferably a HCl solution.

[0023] As a further limitation, the enzyme preparation used in step S3 is one of alkaline protease, trypsin, and papain;

[0024] When alkaline protease is used, the pH value range is 7.5 to 9.5 and the temperature range is 45 to 60°C;

[0025] When using trypsin, the pH range is 7.0 to 8.5 and the temperature range is 35 to 50°C;

[0026] When papain is used, the pH range is 5.5 to 7.0 and the temperature range is 50 to 65°C.

[0027] As a further limitation, after the enzymatic hydrolysis is completed in step S3 and the mass ratio of the unreacted protein powder is ensured to be less than 10%, the unreacted enzyme and macromolecular protein are removed by centrifugation to obtain a solution containing tea seed polypeptides.

[0028] As a further limitation, in step S3, microwave-assisted enzymolysis is used during enzymatic hydrolysis, and the corresponding microwave equipment parameters are: microwave power is between 300 and 800 W; microwave-assisted enzymolysis can shorten the entire enzymatic hydrolysis process to N+5 min, where the letter N corresponds to the microwave treatment time, and the value range is 5 to 15 min.

[0029] As a further limitation, in step S4, the molecular weight cutoff of the ultrafiltration membrane is 3000-10000 Daltons, the ion exchange resin used in the ion exchange chromatography is a strong cation exchange resin, and the gel used in the gel permeation chromatography is Sephadex G-25.

[0030] As a further limitation, in step S5, the tea seed polypeptide solution after ultrafiltration is concentrated to reduce its volume to 1 / 3 to 1 / 2 of the original volume, and then the concentrated solution is dried by spray drying or freeze drying.

[0031] Beneficial effects: The present invention discloses a method for preparing and purifying tea seed polypeptides, which has a simple process flow and is easy to operate. By improving the traditional enzymatic hydrolysis step, not only the production cost is reduced, but also the purity and yield of the polypeptide are improved. In addition, the multi-stage purification technology is used to effectively remove impurities and anti-nutritional factors, thereby improving the extraction efficiency and purity of the tea seed polypeptides. The final product is therefore safer and healthier, and the application field of the tea seed polypeptides is broadened. At the same time, the uniformity of the molecular weight distribution of the tea seed polypeptides in the product is ensured, further improving the quality and application value of the product, ensuring the safety and functionality of the product, and meeting the strict requirements of different application fields for product purity. DETAILED DESCRIPTION

[0032] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0033] In the following embodiments, it will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as the general understanding of those skilled in the art to which this application belongs. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as herein.

[0034] Example 1: In the example, tea seed polypeptide is prepared by the following method:

[0035] In this embodiment, tea seed meal (cake) obtained by cold pressing in an oil pressing plant is used as a raw material for preparing tea seed polypeptides. Mechanical pressing or low-temperature cold pressing can effectively retain the polypeptide components in the tea seed meal and avoid polypeptide denaturation caused by high temperature, so the yield of polypeptide products is higher, but correspondingly, the tea oil yield obtained in the oil processing process is lower than that of the leaching process.

[0036] During preparation, the camellia oleifera seed meal is first crushed to ensure that the particle size of the crushed camellia oleifera seed meal is less than 3 mm. Then, the crushed camellia oleifera seed meal is placed in a container, and clean water is added for soaking, the amount of clean water added is 10 times the weight of the camellia oleifera seed meal, and the mixture is soaked for 8 hours.

[0037] After the soaking is completed, the pH value of the soaking liquid is adjusted to 11 using a 10% (w / v, the same below) NaOH solution, and the soaking liquid is kept in a water bath at 50°C for 100 minutes, during which stirring is maintained, the pH value is continuously measured, and the pH value is corrected at any time to dissolve the protein in the oil tea seed meal. After the treatment is completed, the soaking liquid is allowed to stand for 30 minutes, the supernatant is taken, and the lower mixture is centrifuged at a speed of 5000r / min for 15 minutes to remove insoluble impurities, and the liquid is combined to obtain a tea seed crude protein solution.

[0038] Then, the extracted tea seed crude protein solution was soaked in 10% (w / v, the same below) HCl solution, the pH value of the solution was controlled to 5, and the solution was kept warm in a 50°C water bath for 100 minutes. After the treatment, it was allowed to stand for 30 minutes, the supernatant was taken, and the lower mixture was centrifuged at a speed of 5000 r / min for 15 minutes to obtain a solid. The obtained solid was rinsed with running water until it was neutral, and the solid was freeze-dried and crushed to obtain tea seed protein powder.

[0039] The obtained tea seed protein powder is mixed with alkaline protease, the pH value is adjusted to 8.5, the temperature is adjusted to 55°C, and the enzymolysis reaction is carried out. Stirring is continued during the enzymolysis process, and the reaction time is 3 hours. After the enzymolysis is completed, the enzyme is inactivated by heating to 90°C for 5 minutes, and then centrifuged at a speed of 5000r / min for 15 minutes to remove unreacted protein powder and enzyme preparation (the mass ratio of unreacted protein powder in the unreacted substance is 8.9±0.5%), and the obtained supernatant is a solution containing the target tea seed polypeptide.

[0040] The obtained tea seed polypeptide solution is purified. During the purification process:

[0041] First, a preliminary separation was performed using an ultrafiltration membrane with a molecular weight cutoff of 8000 Daltons to remove large molecular impurities;

[0042] Then, ion exchange chromatography was performed using a strong cation exchange resin for further purification, and the tea seed polypeptides were separated through adsorption and elution steps according to their charge characteristics;

[0043] Finally, Sephadex G-25 gel was used to remove the remaining small molecule impurities in gel permeation chromatography to ensure uniform molecular weight distribution of tea seed polypeptides.

[0044] After the purification is completed, the tea seed polypeptide solution is concentrated and dried to obtain the finished tea seed polypeptide powder. During the concentration process, the volume of the solution is reduced to 1 / 2 of the original volume, and then the concentrated solution is dried by a spray drying process to obtain the final tea seed polypeptide powder product. In this embodiment, the spray drying process has the characteristics of simple operation, fast drying speed, and good product fluidity, and is suitable for large-scale production. During the spray drying process, the solution containing tea seed polypeptides is atomized into fine droplets through a high-pressure nozzle, and then the water is rapidly evaporated under the action of hot air to obtain dry tea seed polypeptide powder. In order to ensure the quality of the product, the drying temperature should be controlled between 45 and 60°C to avoid the influence of high temperature on the activity of the polypeptide.

[0045] Example 2: In the example, tea seed polypeptide is prepared by the following method:

[0046] In this embodiment, tea seed meal obtained by the extraction process in the oil pressing factory is used as a raw material for preparing tea seed polypeptides. Since the extraction process can more thoroughly extract the oil in the tea seed, but at the same time it will also make the protein content in the tea seed meal relatively low, it is possible to consider optimizing the process in the enzymatic hydrolysis stage to increase the polypeptide yield.

[0047] First, the oil tea seed meal was crushed to less than 1mm, and 15 times the weight of clean water was added to soak for 10 hours. After that, the pH was adjusted to 12 with 12% NaOH solution, and kept in a 45℃ water bath for 90 minutes, stirred and the pH value was corrected to dissolve the protein. After the treatment was completed, the supernatant was taken after standing for 40 minutes, and impurities were removed by centrifugation. The liquid was combined to obtain the tea seed crude protein solution.

[0048] The extracted tea seed crude protein solution was treated with 12% HCl, the pH was adjusted to 4.5, and the solution was kept in a water bath at 45°C for 110 minutes. After standing for 40 minutes, the supernatant was taken. The lower mixture was centrifuged to obtain solids. The solids were washed with running water until neutral, freeze-dried, and then crushed to make tea seed protein powder.

[0049] The tea seed protein powder was mixed with trypsin, the pH value was adjusted to 7.5, the temperature was adjusted to 40°C, and the enzymatic reaction was carried out with continuous stirring. The enzyme activity was improved by microwave-assisted technology, the microwave power was set to 600W, and the treatment was carried out for 10 minutes, after which the microwave was stopped and the stirring was continued for 5 minutes. After the enzymatic hydrolysis, the enzyme was inactivated by heating to 85°C for 5 minutes, and then centrifuged to remove the unreacted substances (the mass ratio of the unreacted protein powder in the unreacted substances was 6.2±0.5%) to obtain a solution containing the target tea seed polypeptide.

[0050] The obtained tea seed polypeptide solution was purified. During the purification process: first, an ultrafiltration membrane with a molecular weight cutoff of 5000 Daltons was used for preliminary separation to remove large molecular impurities; then, a strong cation exchange resin was used for further purification by ion exchange chromatography, and separation was performed through adsorption and elution steps according to the charge characteristics of the tea seed polypeptide; finally, Sephadex G-25 gel was used in gel permeation chromatography to remove the remaining small molecular impurities to ensure that the molecular weight distribution of the tea seed polypeptide was uniform.

[0051] The purified tea seed polypeptide solution is concentrated and dried to produce finished powder. The volume is reduced to 1 / 3 during concentration, and then freeze-dried to obtain tea seed polypeptide powder. Freeze-drying technology is characterized by low temperature and stable structure, and is suitable for heat-sensitive substances. This process involves freezing the tea seed polypeptide solution, sublimating and drying it under vacuum to produce powder. To ensure quality, the freezing temperature must be below -40°C and the vacuum degree must be maintained at 0.01-0.05MPa to ensure that moisture is completely removed.

[0052] Example 3: In the example, tea seed polypeptide is prepared by the following method:

[0053] In this embodiment, the camellia seed meal (cake) obtained by the cold pressing process in the oil pressing factory is used as the raw material for preparing tea seed polypeptides. Considering that the camellia seed meal is obtained by the cold pressing process, the corresponding camellia seed meal has a higher oil content, and thus a pre-degreasing treatment can be performed first.

[0054] During the degreasing treatment, the camellia seed meal is crushed to a particle size of less than 3 mm, and then n-hexane is used as an organic solvent for impregnation treatment. The treatment time of a single impregnation treatment is controlled to be 60 minutes, and the cycle is repeated three times. After the impregnation is completed, the solvent is removed by centrifugation to obtain the defatted camellia seed meal. The defatted camellia seed meal is washed with water to remove the residual organic solvent. Finally, the defatted camellia seed meal is dried to reduce the moisture content to less than 5%, that is, the defatting treatment of the camellia seed meal is completed. After the degreasing is completed, the degreasing rate of the corresponding camellia seed meal is measured to be approximately 89% (compared to the camellia seed meal before degreasing).

[0055] Put the defatted camellia seed meal into a container, add clean water to soak, the amount of clean water added is 12 times the weight of the camellia seed meal, soak for 12 hours. Then, adjust the pH to 12 with 15% NaOH solution, keep it in a 35℃ water bath for 120 minutes, stir and correct the pH value to dissolve the protein, let it stand for 30 minutes after the treatment is completed, take the supernatant, centrifuge to remove impurities, and combine the liquids to obtain the camellia seed crude protein solution.

[0056] The extracted tea seed crude protein solution was treated with 13% HCl, the pH was adjusted to 5.0, and the solution was kept in a water bath at 35°C for 120 minutes. After standing for 30 minutes, the supernatant was taken. The lower mixture was centrifuged to obtain solids. The solids were washed with running water until neutral, freeze-dried, and then crushed to make tea seed protein powder.

[0057] Mix tea seed protein powder with papain, adjust the pH value to 6.5, adjust the temperature to 60°C, perform enzymolysis reaction, and continue stirring. Use microwave-assisted technology to improve enzyme activity, set the microwave power to 700W, treat for 15 minutes, then stop the microwave and continue enzymolysis for 5 minutes while stirring. In this process, the role of microwave assistance is mainly to improve enzyme activity and shorten the reaction time, which can greatly shorten the enzymolysis time of 2 to 4 hours under normal stirring. After enzymolysis, heat to 90°C to inactivate the enzyme for 5 minutes, and then centrifuge to remove unreacted substances (the mass ratio of unreacted protein powder in unreacted substances is 4.7±0.5%) to obtain a solution containing the target tea seed polypeptide.

[0058] The obtained tea seed polypeptide solution was purified. During the purification process: first, an ultrafiltration membrane with a molecular weight cutoff of 3000 Daltons was used for preliminary separation to remove large molecular impurities; then, a strong cation exchange resin was used for further purification by ion exchange chromatography, and separation was performed through adsorption and elution steps according to the charge characteristics of the tea seed polypeptide; finally, Sephadex G-25 gel was used in gel permeation chromatography to remove the remaining small molecular impurities to ensure that the molecular weight distribution of the tea seed polypeptide was uniform.

[0059] The purified tea seed polypeptide solution is converted into finished powder during the concentration and drying process. During the concentration stage, the volume is reduced to 1 / 3 of the original volume, and then freeze-drying technology is used for drying to ensure that the freezing temperature is controlled below -40°C and the vacuum degree is maintained between 0.01 and 0.05MPa, ultimately obtaining high-quality tea seed polypeptide powder.

[0060] The tea seed polypeptide powders obtained in the above three groups of embodiments of the present invention can all show good solubility and stability, and show potential application value in the food industry and the medical field. Tea seed polypeptide powder has high biological activity and can be used as a functional food additive to enhance the nutritional value and health care function of food. In the medical field, tea seed polypeptides have biological activities such as antioxidant, anti-inflammatory and immunomodulatory, and can be used to develop new health products and medicines. In addition, tea seed polypeptides also have good moisturizing and anti-wrinkle effects, can be applied to the cosmetics industry, and improve the market competitiveness of products. Through the preparation method of the present invention, high-purity tea seed polypeptides can be effectively extracted from tea seed meal, providing a new source of raw materials for related industries and promoting the comprehensive utilization and sustainable development of resources.

[0061] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A process for preparing and purifying tea seed polypeptide, wherein the process uses tea seed meal as a raw material to prepare and purify tea seed polypeptide, characterized in that: The following steps are involved: S1. Crush the camellia oleifera seed meal, put the crushed pieces into a container, and soak them with clean water. After the soaking is completed, adjust the pH value of the soaking solution to alkaline using an alkaline solution, and keep the pH value of the alkaline soaking solution at 10 to 12; then keep the container in a water bath, and treat it at a temperature of 35 to 55° C. for 90 to 120 minutes, during which stirring is maintained to dissolve the protein in the camellia oleifera seed meal; then remove insoluble impurities by centrifugation to obtain a camellia seed crude protein solution; S2, soaking the extracted tea seed crude protein solution in an acidic soaking solution, maintaining the pH value of the acidic soaking solution at 4.5 to 5.5, then keeping the container in a water bath at a temperature of 35 to 55° C. for 90 to 120 minutes, separating the solid from the liquid to obtain a solid, and washing with running water until neutral; then freeze-drying the solid and crushing it to obtain tea seed protein powder; S3, using the tea tree seed protein powder obtained in step S2 as a raw material, mixing the tea tree seed protein powder with an enzyme preparation, adjusting the pH value and the reaction temperature to the optimal action range of the enzyme, the enzymatic reaction time is 2 to 4 hours, and stirring is continued during the enzymatic hydrolysis process. After the enzymatic hydrolysis is completed, the enzyme is inactivated by heating, and then the unreacted protein powder and enzyme preparation are removed by centrifugation, and the obtained supernatant is a solution containing the target tea seed polypeptide; S4, purifying the tea seed polypeptide solution obtained in step S3, the specific operation sequence is as follows: The tea seed polypeptide solution is initially separated through an ultrafiltration membrane to remove macromolecular impurities; Ion exchange chromatography was used for further purification, using ion exchange resins to adsorb and elute the tea seed polypeptides according to their charge characteristics; Gel permeation chromatography is used to remove the remaining small molecule impurities to ensure uniform molecular weight distribution of tea seed polypeptides; S5. Concentrating the purified tea seed polypeptide solution and drying it to obtain a purified finished tea seed polypeptide powder.

2. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: In step S1, the camellia oleifera meal as the raw material is pre-defatted, and the specific defatting operation method is as follows: The camellia oleifera seed meal is crushed to a particle size of less than 3 mm, and then impregnated with an organic solvent for a period of 30 to 90 minutes. The solvent is then removed by centrifugation to obtain defatted camellia oleifera seed meal. The defatted camellia oleifera seed meal is then washed with water to remove residual organic solvent, and the defatted camellia oleifera seed meal is dried to reduce the moisture content to less than 5%, thereby completing the defatting of the camellia oleifera seed meal.

3. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: The organic solvent is n-hexane, and the organic solvent soaking process is carried out for 3 to 5 times, with a single soaking treatment time of 30 to 90 minutes. After the above degreasing step is completed, the degreasing rate of the camellia seed meal can reach more than 85%.

4. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: In step S1, the camellia seed meal is crushed according to its type before being crushed: for the camellia seed meal obtained by the pressing process, the particle size after crushing after drying or drying is less than 3 mm; for the camellia seed meal obtained by the leaching process, since its particle size is finer, the particle size after crushing after drying or drying is less than 1 mm.

5. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: The alkaline solution used in step S1 is a NaOH solution, and the acidic soaking solution used in step S2 is a HCl solution.

6. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: The enzyme preparation used in step S3 is one of alkaline protease, trypsin and papain; When alkaline protease is used, the pH value range is 7.5 to 9.5 and the temperature range is 45 to 60°C; When using trypsin, the pH range is 7.0 to 8.5 and the temperature range is 35 to 50°C; When papain is used, the pH range is 5.5 to 7.0 and the temperature range is 50 to 65°C.

7. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: After the enzymatic hydrolysis is completed in step S3 and the mass ratio of the unreacted protein powder is ensured to be less than 10%, the unreacted enzyme and macromolecular protein are removed by centrifugal separation to obtain a solution containing tea seed polypeptides.

8. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: In step S3, when performing enzymatic hydrolysis, microwave-assisted enzymatic hydrolysis is used, and the corresponding microwave equipment parameters are: microwave power is between 300 and 800 W; microwave-assisted enzymatic hydrolysis can shorten the entire enzymatic hydrolysis process to N+5 min, where the letter N corresponds to the microwave treatment time, and the value range is 5 to 15 min.

9. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: In step S4, the molecular weight cutoff of the ultrafiltration membrane is 3000-10000 Daltons, the ion exchange resin used in the ion exchange chromatography is a strong cation exchange resin, and the gel used in the gel permeation chromatography is Sephadex G-25.

10. The process for preparing and purifying tea seed polypeptide according to claim 1, characterized in that: In step S5, the tea seed polypeptide solution after ultrafiltration is concentrated to reduce its volume to 1 / 3 to 1 / 2 of the original volume, and then the concentrated solution is dried by spray drying or freeze drying.