Immunity-enhancing instant Pu'er tea powder and preparation method thereof

Abstract

The present invention relates to the technical field of tea products, and discloses an immunity enhancing instant Pu'er tea powder, which comprises, by mass, 55%-70% of a Pu'er tea extract, 1.5%-3.0% of beta-glucan, 0.5%-1.2% of lactoferrin, 3-0.05%-0.15% of vitamin D, 3.0%-5.0% of a tea polyphenol concentrate, and the balance of a microencapsulation carrier. According to the instant Pu'er tea powder capable of enhancing immunity and the preparation method of the instant Pu'er tea powder, beta-glucan, lactoferrin, vitamin D3 and a tea polyphenol concentrate are precisely proportioned, the beta-glucan activates macrophages to phagocytize pathogens, the lactoferrin inhibits inflammatory response, the vitamin D3 promotes immune cell maturation, and the tea polyphenol concentrate is added into the instant Pu'er tea powder. Catechin and caffeine in the tea polyphenol concentrate synergistically resist oxidation, through mixed extraction of cooked tea and raw tea and step-by-step enzymolysis of cellulase and beta-glucanase, the extraction rate of theabrownin and beta-glucan is remarkably increased, and a material basis is provided for immunoregulation.

Description

Technical Field

[0001] The present invention relates to the technical field of tea products, and particularly to an instant Pu-erh tea powder for enhancing immunity and a preparation method thereof. Background Art

[0002] Instant Pu-erh tea powder is a powdery tea product made from Pu-erh tea through processes such as extraction, concentration, and drying, and has the advantages of convenience and good re-dissolubility.

[0003] However, currently, such products generally have the following problems: on the one hand, their functional designs are mostly limited to the traditional effects of Pu-erh tea itself, such as lipid-lowering and stomach protection, lacking scientific compatibility and synergistic enhancement design of targeted functional components (such as β-glucan, lactoferrin, etc.) for improving immunity; on the other hand, existing products are prepared by conventional drying processes, resulting in easy oxidation and inactivation of fat-soluble components such as vitamin D3, and poor stability of active substances such as tea polyphenols during storage, with a short shelf life. Therefore, an instant Pu-erh tea powder for enhancing immunity and a preparation method thereof are proposed. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] Aiming at the deficiencies of the prior art, the present invention provides an instant Pu-erh tea powder for enhancing immunity and a preparation method thereof, which have the advantages of significantly improving the immune regulation function and long-term stability of the product through precise compatibility of functional components and microencapsulation protection technology, and solve the problems of the prior art. On the one hand, its functional design is mostly limited to the traditional effects of Pu-erh tea itself, such as lipid-lowering and stomach protection, lacking scientific compatibility and synergistic enhancement design of targeted functional components (such as β-glucan, lactoferrin, etc.) for improving immunity; on the other hand, existing products are prepared by conventional drying processes, resulting in easy oxidation and inactivation of fat-soluble components such as vitamin D3, and poor stability of active substances such as tea polyphenols during storage, with a short shelf life.

[0006] (2) Technical Solutions

[0007] To achieve the above purpose of significantly improving the immune regulation function and long-term stability of the product through precise compatibility of functional components and microencapsulation protection technology, the present invention provides the following technical solutions: an instant Pu-erh tea powder for enhancing immunity, comprising the following components in mass ratio: Pu-erh tea extract - 55% to 70%, β-glucan - 1.5% to 3.0%, lactoferrin - 0.5% to 1.2%, vitamin D3 - 0.05% to 0.15%, tea polyphenol concentrate - 3.0% to 5.0%, and microencapsulation carrier - the balance;

[0008] The microencapsulated carrier is a complex of modified gum arabic and chitosan, wherein chitosan accounts for 8% to 12% of the total mass of the carrier; the molecular weight of the β-glucan is 200 kDa to 400 kDa, and the purity of lactoferrin is ≥98%.

[0009] Preferably, the Pu-erh tea extract is obtained by mixing ripe tea and raw tea in a mass ratio of (2 - 4):(1 - 3) for extraction.

[0010] Preferably, the tea polyphenol concentrate is obtained by supercritical CO2 extraction, with a purity of ≥90%, and the molar ratio of catechins to caffeine therein is (3 - 5):1.

[0011] Preferably, the modified gum arabic of the microencapsulated carrier is graft-modified with propylene oxide, and the grafting degree is 5% to 8%.

[0012] A preparation method of an instant Pu-erh tea powder for enhancing immunity, including the instant Pu-erh tea powder for enhancing immunity, and further comprising the following steps:

[0013] S1. Raw material pretreatment: Crushing the Pu-erh tea raw material to a particle size of 0.8 mm to 1.2 mm, and treating it under a microwave power of 400 W to 500 W for 6 minutes to 8 minutes to make the inactivation rate of tea polyphenol oxidase ≥95%;

[0014] S2. Multi-stage extraction:

[0015] Step 1: First extraction: Mixing the pretreated Pu-erh tea with distilled water in a mass ratio of 1:18, extracting at 85°C to 90°C for 70 minutes to 80 minutes, and filtering the extract to obtain the first extract;

[0016] Step 2: Second extraction: Adding cellulase (enzyme activity 80,000 U / g to 100,000 U / g) to the residue, enzymatically hydrolyzing at pH 5.2 to pH 5.4 and 48°C to 50°C for 40 minutes to 50 minutes, and then extracting at 65°C to 70°C for 45 minutes to 55 minutes to obtain the second extract;

[0017] Step 3: Third extraction: Adding β-glucanase (enzyme activity 30,000 U / g to 40,000 U / g) to the residue, enzymatically hydrolyzing at pH 6.2 to pH 6.4 and 52°C to 54°C for 45 minutes to 55 minutes, and then extracting at 75°C to 80°C for 35 minutes to 45 minutes to obtain the third extract;

[0018] S3. Component enhancement: Combining the first, second, and third extracts, adding β-glucan, lactoferrin, vitamin D3, and tea polyphenol concentrate, mixing evenly, and then adjusting the pH to 6.9 to 7.1;

[0019] S4. Microencapsulation: The emulsification-spray drying method is adopted. The emulsification process parameters are as follows: the emulsification rotation speed is 12,000 rpm to 15,000 rpm, the mass ratio of the wall material to the core material is 1:1, the inlet air temperature for spray drying is 165°C to 175°C, and the outlet air temperature is 85°C to 95°C;

[0020] S5. Drying and packaging: Dry at a vacuum degree of -0.09 MPa to -0.1 MPa and a temperature of 45°C to 50°C until the moisture content ≤ 2.5%.

[0021] Preferably, the addition amount of cellulase is 0.15% to 0.25% of the raw material quality, and the addition amount of β-glucanase is 0.2% to 0.3% of the raw material quality.

[0022] Preferably, the particle size of the microencapsulation product is 80 μm to 120 μm, the embedding rate ≥ 90%, and the surface of the microcapsule is subjected to molecular inclusion by β-cyclodextrin.

[0023] Preferably, vitamin D3 is dispersed in the extract in the form of a microemulsion. The particle size of the microemulsion ≤ 100 nm, and Tween 80 and phosphatidylcholine are used as emulsifiers.

[0024] Preferably, the moisture content of the raw material after microwave treatment ≤ 5%, and a near-infrared spectrometer is used to monitor the degree of enzyme inactivation in real time.

[0025] (III) Beneficial effects

[0026] Compared with the prior art, the present invention provides an instant Pu-erh tea powder for enhancing immunity and its preparation method, which has the following beneficial effects:

[0027] 1. For the instant Pu-erh tea powder for enhancing immunity and its preparation method, the precise ratio of β-glucan, lactoferrin, vitamin D3 and tea polyphenol concentrate is adopted. β-glucan activates macrophages to phagocytize pathogens, lactoferrin inhibits inflammatory reactions, vitamin D3 promotes the maturation of immune cells, and catechins and caffeine in the tea polyphenol concentrate synergistically have antioxidant effects. By mixing and extracting ripe tea and raw tea (mass ratio 2 - 4:1 - 3), combined with stepwise enzymatic hydrolysis with cellulase and β-glucanase, the extraction rates of theabrownin and β-glucan are significantly improved, providing a material basis for immune regulation.

[0028] 2. The instant Pu-erh tea powder for enhancing immunity and its preparation method use a composite carrier of propylene oxide-modified arabic gum and chitosan. The active ingredients are encapsulated into microcapsules with a size of 80 - 120 μm through an emulsification-spray drying process. The modified arabic gum forms a hydrophobic barrier, and chitosan adsorbs lipophilic components through hydrogen bonding. β-cyclodextrin encapsulates and captures free radicals on the surface of the microcapsules. This triple structure effectively protects vitamin D3 and tea polyphenols, increasing the retention rate of vitamin D3 to 89% (only 45% in the conventional process) and reducing the oxidation rate of tea polyphenols to 8%. At the same time, the microemulsion dispersion technology enhances the absorption and utilization of vitamin D3 and extends the shelf life of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flowchart of the preparation method of the instant Pu-erh tea powder for enhancing immunity of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments and drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] Please refer to Figure 1 , an instant Pu-erh tea powder for enhancing immunity, comprising the following components in mass ratio: Pu-erh tea extract - 55% to 70%, β-glucan - 1.5% to 3.0%, lactoferrin - 0.5% to 1.2%, vitamin D3 - 0.05% to 0.15%, tea polyphenol concentrate - 3.0% to 5.0%, and microencapsulated carrier - the balance;

[0032] The microencapsulated carrier is a composite of modified arabic gum and chitosan, wherein chitosan accounts for 8% to 12% of the total mass of the carrier; the molecular weight of the β-glucan is 200 kDa to 400 kDa, and the purity of lactoferrin ≥ 98%.

[0033] A preparation method of an instant Pu-erh tea powder for enhancing immunity, including the instant Pu-erh tea powder for enhancing immunity, and further comprising the following steps:

[0034] S1. Raw material pretreatment: Crush the Pu-erh tea raw material to a particle size of 0.8 mm to 1.2 mm, and treat it under a microwave power of 400 W to 500 W for 6 minutes to 8 minutes to inactivate the tea polyphenol oxidase with a inactivation rate ≥ 95%;

[0035] S2. Multi-stage extraction:

[0036] Step 1: First extraction: Mix the pre-treated Pu-erh tea with distilled water at a mass ratio of 1:18, extract at 85°C to 90°C for 70 minutes to 80 minutes, and filter the extract to obtain the first extract;

[0037] Step 2: Second extraction: Add cellulase (enzyme activity 80,000 U / g to 100,000 U / g) to the residue, enzymatically hydrolyze at pH 5.2 to pH 5.4 and 48°C to 50°C for 40 minutes to 50 minutes, and then extract at 65°C to 70°C for 45 minutes to 55 minutes to obtain the second extract;

[0038] Step 3: Third extraction: Add β-glucanase (enzyme activity 30,000 U / g to 40,000 U / g) to the residue, enzymatically hydrolyze at pH 6.2 to pH 6.4 and 52°C to 54°C for 45 minutes to 55 minutes, and then extract at 75°C to 80°C for 35 minutes to 45 minutes to obtain the third extract;

[0039] S3. Component enhancement: Combine the first, second, and third extracts, add β-glucan, lactoferrin, vitamin D3, and tea polyphenol concentrate, mix evenly, and adjust the pH to 6.9 to 7.1;

[0040] S4. Microencapsulation: Use the emulsification-spray drying method, where the emulsification process parameters are: emulsification rotation speed 12,000 rpm to 15,000 rpm, mass ratio of wall material to core material 1:1, inlet temperature of spray drying 165°C to 175°C, and outlet temperature 85°C to 95°C;

[0041] S5. Drying and packaging: Dry at a vacuum of -0.09 MPa to -0.1 MPa and a temperature of 45°C to 50°C until the moisture content ≤ 2.5%.

[0042] Example 1:

[0043] This example verifies the synergistic effect of the formula and process parameters of the present invention and compares the influence of different processes on the product performance.

[0044] I. Experimental parameters

[0045] Pu-erh tea raw material: Yunnan large-leaf sun-dried green tea (ripe tea: raw tea = 3:2);

[0046] β-glucan (molecular weight 300 kDa, purity 95%);

[0047] Lactoferrin (purity 98.5%);

[0048] Vitamin D3 microemulsion (particle size 80 nm, Tween 80:phosphatidylcholine = 3:1);

[0049] Tea polyphenol concentrate (extracted by supercritical CO2, purity 92%, catechin:caffeine = 4:1);

[0050] Complex of modified arabic gum (degree of propylene oxide grafting 6.5%) and chitosan (proportion of chitosan 10%).

[0051] II. Preparation steps

[0052] Step 1: Raw material pretreatment

[0053] Pu-erh tea is crushed to a particle size of 1.0 mm, treated with a microwave power of 450 W for 7 minutes. Near-infrared spectroscopy monitoring shows that the inactivation rate of tea polyphenol oxidase is 96.2% and the moisture content is 4.8%;

[0054] Step 2: Multi-stage extraction

[0055] First extraction: The solid-liquid ratio is 1:18, extraction is carried out at 88 °C for 75 minutes to obtain the first extraction solution (tea polyphenol concentration 3.2 g / L);

[0056] Second extraction: The residue is added with 0.2% cellulase (enzyme activity 90,000 U / g), enzymatically hydrolyzed at pH 5.3 and 49 °C for 45 minutes, and then extracted at 68 °C for 50 minutes to obtain the second extraction solution (polysaccharide content 1.8 g / L);

[0057] Third extraction: The residue is added with 0.25% β-glucanase (enzyme activity 35,000 U / g), enzymatically hydrolyzed at pH 6.3 and 53 °C for 50 minutes, and then extracted at 78 °C for 40 minutes to obtain the third extraction solution (β-glucan concentration 0.9 g / L);

[0058] Step 3: Component enhancement

[0059] The three extraction solutions are combined, and β-glucan (2.5%), lactoferrin (0.8%), vitamin D3 microemulsion (0.1%) and tea polyphenol concentrate (4.0%) are added, and the pH is adjusted to 7.0;

[0060] Step 4: Microencapsulation treatment

[0061] The emulsification speed is 13,500 rpm, the wall material:core material = 1:1, the inlet air temperature of spray drying is 170 °C / the outlet air temperature is 90 °C, and microcapsules are prepared (particle size 100 μm, embedding rate 92%, surface β-cyclodextrin inclusion rate 85%);

[0062] Step 5: Drying and packaging

[0063] Drying is carried out under a vacuum of -0.095 MPa and at 48 °C until the moisture content reaches 2.1%, and nitrogen filling packaging is carried out with aluminum foil bags.

[0064] III. Test results

[0065] Table 1 Basic formula and process verification experiment

[0066]

[0067]

[0068] The experimental group was significantly superior to the control group in terms of component stability, immunomodulatory activity, and usage experience, verifying the synergistic optimization effect of the formula and process.

[0069] Example Two:

[0070] This example studies the effect of the chitosan ratio on the properties of graft-modified gum arabic.

[0071] I. Experimental parameters

[0072] Group Degree of grafting of modified arabic gum Proportion of chitosan in the carrier β-cyclodextrin inclusion rate Experimental group A 6.5％ 10％ 85％ Control group A1 6.5％ 5％ 85％ Control group A2 6.5％ 15％ 85％ Control group A3 Unmodified arabic gum 10％ 85％

[0073] II. Preparation steps

[0074] Step 1. Carrier modification:

[0075] Experimental group A: React gum arabic with propylene oxide at a ratio of 100:6.5 (w / w), catalyzed by NaOH (pH = 10), stir at 50 °C for 3 h to obtain graft-modified gum arabic with a grafting degree of 6.5%.

[0076] Control group A3: Use unmodified gum arabic.

[0077] Step 2. Microencapsulation process:

[0078] The emulsification rotation speed is 13,500 rpm, the mass ratio of the wall material (modified gum arabic: chitosan = 9:1) to the core material is 1:1, and the inlet air temperature for spray drying is 170 °C / the outlet air temperature is 90 °C.

[0079] III. Test results

[0080] Table 2 Experiment on the effect of chitosan ratio on the properties of graft-modified gum arabic

[0081] Test item Experimental group A Control group A1 Control group A2 Control group A3 Entrapment rate 92.3％ 81.5％ 88.7％ 75.2％ Microcapsule particle size (μm) 100 125 95 140 Moisture absorption rate (40°C, 75% RH) 2.1％ 3.8％ 2.8％ 5.2％ Retention rate of vitamin D3 89.3％ 68.2％ 82.5％ 55.4％

[0082] When the chitosan ratio is 10%, the microcapsule structure formed by the carrier is the most stable, and the embedding rate and component retention rate are significantly better than those of other groups.

[0083] Example Three:

[0084] This example explores the effects of different extraction conditions on the purity of tea polyphenol concentrate and the ratio of catechin / caffeine.

[0085] I. Experimental parameters

[0086] Group Extraction pressure (MPa) Extraction temperature (°C) Proportion of entrainer (ethanol) Experimental group B 25 45 10％ Control group B1 20 40 5％ Control group B2 30 50 15％

[0087] II. Preparation Steps

[0088] Step 1: Supercritical CO2 Extraction:

[0089] The raw materials are crushed to 40 mesh and filled into the extraction kettle, with a CO2 flow rate of 20 L / h;

[0090] Experimental Group B: Pressure 25 MPa, temperature 45 °C, ethanol entrainer 10%, extraction for 2 h.

[0091] Step 2: Concentrate Analysis:

[0092] Detect the contents of catechins (ECG, EGCG, etc.) and caffeine by HPLC.

[0093] III. Test Results

[0094] Table 3 Experiment on the Influence of Extraction Conditions on the Purity of Tea Polyphenol Concentrate and the Ratio of Catechin / Caffeine

[0095] Test item Experimental group B Control group B1 Control group B2 Purity of tea polyphenols (%) 92.1％ 85.3％ 90.2％ Catechin / caffeine (mol ratio) 4.2:1 2.8:1 3.5:1 Antioxidant activity (ABTS method, μmolTE / g) 2850 2100 2500

[0096] Under the conditions of 25 MPa / 45 °C / 10% ethanol, the purity of tea polyphenols is the highest and the ratio of catechins is the best, with the antioxidant activity increased by 35%.

[0097] Example 4:

[0098] This example studies the influence of microemulsion particle size and emulsifier ratio on the stability of vitamin D3.

[0099] I. Experimental Parameters

[0100] Group Emulsifier ratio (T80:PC) Homogenization pressure (MPa) Microemulsion particle size (nm) Experimental group C 3:1 150 80 Control group C1 1:1 100 120 Control group C2 5:1 200 60

[0101] II. Preparation Steps

[0102] Step 1: Microemulsion Preparation:

[0103] Dissolve vitamin D3 in soybean oil (oil phase), and the aqueous phase contains T80, PC and phosphate buffer solution;

[0104] Experimental Group C: High-speed shearing (15,000 rpm) for 5 min and then high-pressure homogenization (150 MPa) 3 times.

[0105] Step 2: Stability Test:

[0106] Accelerated oxidation experiment (stored at 60 °C in the dark for 10 days), detect the content of vitamin D3 by HPLC.

[0107] III. Test Results

[0108] Table 4 Experiment on the Influence of Microemulsion Particle Size and Emulsifier Ratio on the Stability of Vitamin D3

[0109] Test item Experimental group C Control group C1 Control group C2 Initial entrapment rate (%) 95.2％ 88.7％ 93.1％ Retention rate after 10 days of storage (%) 89.3％ 72.5％ 85.2％ In vitro release rate (2h, pH = 7.4) 68.5％ 55.2％ 72.1％

[0110] T80: When the PC is 3:1 and under the homogenization condition of 150 MPa, the comprehensive performance is optimal when the microemulsion particle size is 80 nm, which not only ensures stability but also improves bioavailability.

[0111] Example Five:

[0112] This example verifies the effect of compound enzymatic hydrolysis on the extraction rate of active ingredients.

[0113] I. Experimental Parameters

[0114] Group Cellulase addition amount β-glucanase addition amount Solid content concentration of the extract (g / L) Experimental group D 0.2％ 0.25％ 8.5 Control group D1 0％ 0％ 5.2 Control group D2 0.2％ 0％ 6.8 Control group D3 0％ 0.25％ 6.3

[0115] II. Preparation Steps

[0116] Step 1. Multi-stage extraction:

[0117] Experimental group D: Add 0.2% cellulase (90,000 U / g) for the second extraction and 0.25% β-glucanase (35,000 U / g) for the third extraction;

[0118] Step 2. Component analysis:

[0119] Detect the contents of theabrownin, β-glucan, and tea polyphenols by high performance liquid chromatography.

[0120] III. Test Results

[0121] Table 5 Experiment on the effect of compound enzymatic hydrolysis on the extraction rate of active ingredients

[0122] Test item Experimental group D Control group D1 Control group D2 Control group D3 Extraction rate of theabrownin (%) 78.3％ 45.2％ 58.1％ 52.4％ β-glucan concentration (g / L) 1.2 0.5 0.7 0.8 Total polyphenol retention rate (%) 82.1％ 65.3％ 72.5％ 68.9％

[0123] Compound enzymatic hydrolysis significantly improves the dissolution rate of macromolecular substances. The extraction rate of theabrownin increases by 73%, and the concentration of β-glucan increases by 140%.

[0124] In summary, for the instant Pu-erh tea powder with enhanced immunity and its preparation method, the precise ratio of β-glucan, lactoferrin, vitamin D3, and tea polyphenol concentrate is adopted. β-glucan activates macrophages to phagocytize pathogens, lactoferrin inhibits inflammatory reactions, vitamin D3 promotes the maturation of immune cells, and catechins and caffeine in the tea polyphenol concentrate synergistically have antioxidant effects. By mixing and extracting ripe tea and raw tea (mass ratio 2 - 4:1 - 3) and combining stepwise enzymatic hydrolysis with cellulase and β-glucanase, the extraction rates of theabrownin and β-glucan are significantly improved, providing a material basis for immune regulation.

[0125] Moreover, for the instant Pu-erh tea powder for enhancing immunity and its preparation method, a composite carrier of propylene oxide-modified arabic gum and chitosan is used. Through the emulsification-spray drying process, the active ingredients are encapsulated into microcapsules with a size of 80 - 120 μm. The modified arabic gum forms a hydrophobic barrier, chitosan adsorbs lipophilic components through hydrogen bonding, and β-cyclodextrin entraps free radicals on the surface of the microcapsules. This triple structure effectively protects vitamin D3 and tea polyphenols, increasing the retention rate of vitamin D3 to 89% (only 45% in the conventional process) and reducing the oxidation rate of tea polyphenols to 8%. Meanwhile, the microemulsion dispersion technology enhances the absorption and utilization of vitamin D3 and extends the shelf life of the product, solving the problems in the prior art. On the one hand, the functional design is mostly limited to the traditional effects of Pu-erh tea itself, such as lipid-lowering and stomach protection, lacking the scientific compatibility and synergistic design of targeted functional components (such as β-glucan, lactoferrin, etc.) for improving immunity. On the other hand, the existing products are prepared by conventional drying processes, resulting in the easy oxidation and inactivation of fat-soluble components such as vitamin D3, and the poor stability of active substances such as tea polyphenols during storage, with a short shelf life.

[0126] All relevant modules involved in this system are hardware system modules or functional modules formed by combining computer software programs or protocols in the prior art with hardware. The computer software programs or protocols themselves involved in this functional module are all well-known technologies to those skilled in the art and are not the improvements of this system. The improvement of this system lies in the interaction relationship or connection relationship between each module, that is, the overall structure of the system is improved to solve the corresponding technical problems to be solved by this system.

[0127] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An instant Pu'er tea powder for enhancing immunity, characterized in that: The invention comprises the following ingredients in the following mass ratios: Pu'er tea extract - 55% to 70%, beta-glucan - 1.5% to 3.0%, lactoferrin - 0.5% to 1.2%, vitamin D3 - 0.05% to 0.15%, tea polyphenol concentrate - 3.0% to 5.0% and microencapsulation carrier - the balance; The microencapsulated carrier is a complex of modified gum arabic and chitosan, wherein the chitosan accounts for 8% to 12% of the total mass of the carrier; the molecular weight of the beta-glucan is 200kDa to 400kDa, and the purity of lactoferrin is ≥98%.

2. The instant Pu'er tea powder for enhancing immunity according to claim 1, characterized in that: The Pu'er tea extract is obtained by mixing and extracting cooked tea and raw tea in a mass ratio of (2-4):(1-3).

3. The instant Pu'er tea powder for enhancing immunity according to claim 1, characterized in that: The tea polyphenol concentrate is obtained by supercritical CO2 extraction, has a purity of ≥90%, and has a molar ratio of catechins to caffeine of (3-5):

1.

4. The instant Pu'er tea powder for enhancing immunity according to claim 1, characterized in that: The modified gum arabic of the microencapsulation carrier is modified by propylene oxide grafting, and the grafting degree is 5% to 8%.

5. A method for preparing instant Pu'er tea powder for enhancing immunity, characterized in that: The instant Pu'er tea powder for enhancing immunity according to claims 1 to 4 further comprises the following steps: S1. Raw material pretreatment: crush the Pu'er tea raw material into particles of 0.8 mm to 1.2 mm, and treat it at a microwave power of 400 W to 500 W for 6 to 8 minutes to make the inactivation rate of tea polyphenol oxidase ≥ 95%; S2, multi-level extraction: Step 1: First extraction: Mix the pretreated Pu'er tea with distilled water in a mass ratio of 1:18, extract at 85°C to 90°C for 70 minutes to 80 minutes, and filter the extract to obtain a first extract; Step 2: Second extraction: adding cellulase (enzyme activity 80,000 U / g to 100,000 U / g) to the residue, performing enzymolysis at pH 5.2 to pH 5.4 and 48° C. to 50° C. for 40 to 50 minutes, and then extracting at 65° C. to 70° C. for 45 to 55 minutes to obtain a second extract; Step 3: third extraction: add β-glucanase (enzyme activity 30,000 U / g to 40,000 U / g) to the residue, perform enzymolysis at pH 6.2 to pH 6.4 and 52° C. to 54° C. for 45 to 55 minutes, and then extract at 75° C. to 80° C. for 35 to 45 minutes to obtain a third extract; S3, component strengthening: combine the first, second and third extracts, add β-glucan, lactoferrin, vitamin D3 and tea polyphenol concentrate, mix well and adjust the pH to 6.9 to 7.1; S4, microencapsulation: using emulsification-spray drying method, wherein the emulsification process parameters are: emulsification speed 12,000rpm to 15,000rpm, wall material to core material mass ratio 1:1, spray drying inlet air temperature 165℃ to 175℃, outlet air temperature 85℃ to 95℃; S5. Drying and packaging: Dry at a vacuum degree of -0.09MPa to -0.1MPa and a temperature of 45°C to 50°C to a moisture content of ≤2.5%.

6. The method for preparing the instant Pu'er tea powder for enhancing immunity according to claim 5, characterized in that: In the step S2, the amount of cellulase added is 0.15% to 0.25% of the mass of the raw material, and the amount of β-glucanase added is 0.2% to 0.3% of the mass of the raw material.

7. The method for preparing the instant Pu'er tea powder for enhancing immunity according to claim 5, characterized in that: In the step S4, the particle size of the microencapsulated product is 80 μm to 120 μm, the embedding rate is ≥ 90%, and the surface of the microcapsule is molecularly included by β-cyclodextrin.

8. The method for preparing the instant Pu'er tea powder for enhancing immunity according to claim 5, characterized in that: In the step S3, vitamin D3 is dispersed in the extract in the form of microemulsion, the particle size of the microemulsion is ≤100 nm, and Tween 80 and phosphatidylcholine are used as emulsifiers.

9. The method for preparing the instant Pu'er tea powder for enhancing immunity according to claim 5, characterized in that: In the step S1, the moisture content of the raw material after microwave treatment is ≤5%, and a near infrared spectrometer is used to monitor the degree of enzyme inactivation in real time.

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