Protein powder and preparation method thereof

Abstract

The invention relates to the technical field of food and health food, in particular to protein powder and a preparation technology thereof.

Description

Technical Field

[0001] The present invention relates to the technical fields of food and health food, and particularly relates to a protein powder and its preparation technology. Background Art

[0002] Protein is the material basis of all life and the main bearer of life activities. Protein, fat, and carbohydrates are collectively referred to as the three major nutrients in the human body. Supplementing protein can enhance immunity, improve physical fitness, increase satiety, and maintain muscle mass. There are various health foods for supplementing protein on the market. Protein powder is the most common protein supplement. Soy protein is widely used as a raw material in protein powder products due to its excellent amino acid ratio and high digestibility.

[0003] Protein powder belongs to the powder form and needs to be brewed during consumption. The spatial structure and surface properties of some proteins determine that they are not easily soluble in water. For example, soy protein isolate is processed from low-temperature soybean meal after soybean pressing through multiple extraction and spray drying processes. The soy protein isolate powder after spray drying is finer, and the finer powder will agglomerate due to electrostatic attraction. When the soy protein isolate powder first contacts the water surface, the outer layer of the aggregated powder quickly contacts the water to form a gel surface layer, and the inside of the powder mass cannot contact the water, so it is difficult to dissolve and needs to be opened with external force, which brings inconvenience to consumers.

[0004] The dispersion stability of powder in water generally includes the following three processes: wetting, dispersion, and dispersion stability. Only after the wetting process can the air on the solid surface be replaced by the liquid. The powder can further dissolve in water. Therefore, the wetting speed largely determines the dissolution speed of the powder.

[0005] Existing commercially available products often use anti-caking agents (such as silica, tricalcium phosphate, etc.) to increase the fluidity of the protein powder so that the powder is not easily agglomerated and indirectly improve the solubility of the product. There are also applications of fluidized beds to spray phospholipids on the surface of protein powder for granulation to increase fluidity, but the ability of the powder to be wetted is not fundamentally solved.

[0006] The fluidized bed granulation disclosed in the prior art is to put the materials (including anti-caking agents) into a closed container at one time, uniformly mix the materials in the container, and then evenly spray the binder into the container through the equipment, so that the binder and the materials are fully mixed and flow in the container to form small particles. Hot air is sent in through the bottom to dry the wet particles, and finally the finished dry particles are directly collected. However, the prior art does not disclose the granulation end point. When the fluidized bed was used to granulate protein powder in the past, it was generally believed that the longer the fluidization time, the higher the degree of granulation, the larger the particle size, and the better the solubility of the obtained particles. But it often consumes too much production time, and the result cannot achieve the best effect. Summary of the Invention

[0007] The object of the present invention is to provide a protein powder with rapid wetting and its preparation method, which is used to solve the technical problems of slow dissolution rate of protein powder and difficulty in determining the end point of fluidized bed granulation. The present invention provides a protein powder, and the wetting rate of the protein powder does not exceed 100 seconds.

[0008] Protein powder

[0009] The first aspect of the present invention provides a protein powder, and the particle size distribution d(0.5) thereof is 50 - 90 μm.

[0010] In certain embodiments, the Carr's coefficient of the protein powder is 13% - 30%.

[0011] In certain embodiments, the bulk density of the protein powder is 0.25 - 0.35 g / mL.

[0012] In certain embodiments, the particle size distribution d(0.5) of the protein powder is 50 - 90 μm, the Carr's coefficient is 13% - 30%, and the bulk density is 0.25 - 0.35 g / mL.

[0013] In certain embodiments, the particle size distribution d(0.5) of the protein powder is 52 - 85 μm.

[0014] In certain embodiments, the particle size distribution d(0.5) of the protein powder is 53 - 80 μm.

[0015] In certain embodiments, the particle size distribution d(0.5) of the protein powder is 54 - 78 μm.

[0016] In certain embodiments, the Carr's coefficient of the protein powder is 16% - 28%.

[0017] In certain embodiments, the Carr's coefficient of the protein powder is 18% - 26%.

[0018] In certain embodiments, the Carr's coefficient of the protein powder is 19% - 25%.

[0019] In certain embodiments, the bulk density of the protein powder is 0.27 - 0.32 g / mL.

[0020] In certain embodiments, the bulk density of the protein powder is 0.28 - 0.30 g / mL.

[0021] In certain embodiments, the protein powder does not contain anticaking agents and / or phospholipids.

[0022] In certain embodiments, the anticaking agent is selected from silica, tricalcium phosphate, magnesium stearate, calcium stearate, potassium stearate, microcrystalline cellulose, sodium pyrophosphate, sodium hexametaphosphate, ferric tartrate, carnauba wax, talc, calcium silicate, sodium acid pyrophosphate, calcium dihydrogen phosphate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, dipotassium hydrogen phosphate, calcium hydrogen phosphate, tripotassium phosphate, trisodium phosphate, sodium hexametaphosphate, sodium tripolyphosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, tetrapotassium pyrophosphate, trisodium monohydrogen pyrophosphate, potassium metaphosphate, calcium acid pyrophosphate, ammonium ferric citrate, magnesium carbonate, phosphoric acid, sodium pyrophosphate, calcium acid pyrophosphate, and polyglycerol fatty acid esters.

[0023] In certain embodiments, the protein powder is prepared from a protein powder raw material and water by a fluidized bed granulator.

[0024] In certain embodiments, the fluidized bed granulator is a top-spray or bottom-spray fluidized bed granulator.

[0025] In certain embodiments, the fluidized bed granulator is a bottom-spray fluidized bed granulator.

[0026] In certain embodiments, the protein powder raw material is selected from one or more of milk protein, whey protein, casein, soy protein, soy isolate, rice protein, wheat protein, and pea protein.

[0027] In certain embodiments, the protein powder raw material is selected from one or more of soy isolate, rice protein, and pea protein.

[0028] In certain embodiments, the protein powder is prepared by a method comprising the following steps:

[0029] (1) Feed the protein powder raw material into a fluidized bed granulator,

[0030] (2) Spray water for granulation.

[0031] In certain embodiments, in step (2), the water spraying speed is 3 - 55 g / min.

[0032] In certain embodiments, the water spraying speed is 5 - 45 g / min.

[0033] In certain embodiments, the water spraying speed is 8 - 38 g / min.

[0034] In certain embodiments, the water spraying speed is 11 - 30 g / min.

[0035] In certain embodiments, step (2) has one or more of the following technical features:

[0036] a) The spraying amount of water is 20 wt% - 60 wt% of the total amount of the protein powder raw material,

[0037] b) The material temperature is controlled at 30 - 50 °C,

[0038] c) The atomization pressure is 0.1 - 0.6 bar.

[0039] In certain embodiments, the spraying amount of water is 25 wt% - 50 wt% of the total amount of the protein powder raw material.

[0040] In certain embodiments, the spraying amount of water is 30 wt% - 40 wt% of the total amount of the protein powder raw material.

[0041] In certain embodiments, the material temperature is controlled at 32 - 43 °C.

[0042] In certain embodiments, the atomization pressure is 0.2 - 0.6 bar.

[0043] In certain embodiments, the fluidized bed granulator is a bottom - spray fluidized bed granulator.

[0044] In certain embodiments, in step (2), the water spraying speed is 18 - 45 g / min, the spraying amount of water is 40 wt% - 50 wt% of the total amount of the protein powder raw material, the material temperature is controlled at 30 - 37 °C, and the atomization pressure is 0.3 - 0.6 bar.

[0045] In certain embodiments, in step (2), the water spraying speed is 18 - 30 g / min, the spraying amount of water is 40 wt% of the total amount of the protein powder raw material, the material temperature is controlled at 32 - 37 °C, and the atomization pressure is 0.3 - 0.6 bar.

[0046] In certain embodiments, the fluidized bed granulator is a top - spray fluidized bed granulator.

[0047] In certain embodiments, in step (2), the water spraying speed is 5 - 15 g / min, the spraying amount of water is 25 wt% - 35 wt% of the total amount of the protein powder raw material, the material temperature is controlled at 40 - 50 °C, and the atomization pressure is 0.1 - 0.2 bar.

[0048] In certain embodiments, in step (2), the water spraying speed is 11 g / min, the spraying amount of water is 30 wt% of the total amount of the protein powder raw material, the material temperature is controlled at 43 °C, and the atomization pressure is 0.2 bar.

[0049] Preparation method

[0050] The second aspect of the present invention provides a method for preparing the protein powder described in the first aspect, including:

[0051] (1) Put the protein powder raw material into the fluidized bed granulator,

[0052] (2) Granulation is carried out by spraying water.

[0053] In certain embodiments, the protein powder raw material is selected from one or more of milk protein, whey protein, casein, soy protein, soy protein isolate, rice protein, wheat protein, and pea protein.

[0054] In certain embodiments, the protein powder raw material is selected from one or more of soy protein isolate, rice protein, and pea protein.

[0055] In certain embodiments, the fluidized bed granulator is a top-spray or bottom-spray fluidized bed granulator.

[0056] In certain embodiments, in step (2), the water spraying speed is 3 - 55 g / min.

[0057] In certain embodiments, the water spraying speed is 5 - 45 g / min.

[0058] In certain embodiments, the water spraying speed is 8 - 38 g / min.

[0059] In certain embodiments, the water spraying speed is 11 - 30 g / min.

[0060] In certain embodiments, step (2) has one or more of the following technical features:

[0061] a) The spray amount of water is 20 wt% - 60 wt% of the total amount of the protein powder raw material,

[0062] b) The material temperature is controlled at 30 - 50 °C,

[0063] c) The atomization pressure is 0.1 - 0.6 bar.

[0064] In certain embodiments, the spray amount of water is 25 wt% - 50 wt% of the total amount of the protein powder raw material.

[0065] In certain embodiments, the spray amount of water is 30 wt% - 40 wt% of the total amount of the protein powder raw material.

[0066] In certain embodiments, the material temperature is controlled at 32 - 43 °C.

[0067] In certain embodiments, the atomization pressure is 0.2 - 0.6 bar.

[0068] In certain embodiments, the fluidized bed granulator is a bottom-spray fluidized bed granulator.

[0069] In certain embodiments, in step (2), the water spraying speed is 18 - 45 g / min, the water spraying amount is 40 wt% - 50 wt% of the total amount of the protein powder raw material, the material temperature is controlled at 30 - 37 °C, and the atomization pressure is 0.3 - 0.6 bar.

[0070] In certain embodiments, in step (2), the water spraying speed is 18 - 30 g / min, the water spraying amount is 40 wt% of the total amount of the protein powder raw material, the material temperature is controlled at 32 - 37 °C, and the atomization pressure is 0.3 - 0.6 bar.

[0071] In certain embodiments, the fluidized bed granulator is a top - spray fluidized bed granulator.

[0072] In certain embodiments, in step (2), the water spraying speed is 5 - 15 g / min, the water spraying amount is 25 wt% - 35 wt% of the total amount of the protein powder raw material, the material temperature is controlled at 40 - 50 °C, and the atomization pressure is 0.1 - 0.2 bar.

[0073] In certain embodiments, in step (2), the water spraying speed is 11 g / min, the water spraying amount is 30 wt% of the total amount of the protein powder raw material, the material temperature is controlled at 43 °C, and the atomization pressure is 0.2 bar.

[0074] Composition

[0075] The third aspect of the present invention provides a composition, which comprises the protein powder described in the first aspect of the present invention.

[0076] In certain embodiments, the composition further comprises nutrients.

[0077] In certain embodiments, the nutrients are selected from calcium, iron, zinc, and / or various vitamins.

[0078] In certain embodiments, the vitamins are selected from vitamin A, vitamin B1, vitamin B2, niacin, pantothenic acid, vitamin B6, biotin, folic acid, vitamin B12, vitamin C, vitamin D, vitamin E, and vitamin K.

[0079] Term Definition

[0080] In the present invention, the term "milk protein", also known as bovine milk protein, is the general name of many kinds of protein mixtures in milk, mainly composed of two major parts: casein and whey protein. In the present invention, "casein" is the protein precipitated from milk at 20 °C and pH value 4.6, and the remaining proteins dissolved in whey are all called whey protein. In the present invention, "whey protein" includes β - lactoglobulin, α - lactalbumin, serum albumin, and immunoglobulins, as well as other trace proteins, such as copper - containing, zinc - superoxide dismutase, etc.

[0081] In the present invention, the term "soybean protein" is a high-quality vegetable protein derived from soybeans, rich in various essential amino acids for the human body, with a protein content greater than 38%. The amino acid composition of soybean protein is similar to that of milk protein, rich in nutrition, but cholesterol-free and rich in fiber, which can help the digestive system stay healthy.

[0082] In the present invention, the term "soybean isolate" is obtained by leaching soybean meal (removing oil and water-soluble non-protein components) in an alkaline solution under low-temperature conditions, followed by precipitation, washing, and drying to obtain a protein powder with a protein content greater than 90%. Its structure and properties basically replace pure soybean protein. There are nearly 20 kinds of amino acids in soybean isolate, and it contains essential amino acids for the human body. It is rich in nutrition and is one of the few varieties of vegetable proteins that can replace animal proteins.

[0083] In the present invention, the term "rice protein" is derived from rice and is a traditional protein source with low allergenicity and easy digestibility. Rice is the only grain that can be exempted from allergy tests, gluten-free, and one of the most easily digested staple foods. The amino acid composition of rice protein is reasonable, and it is the most easily digested protein source among mainstream vegetable proteins.

[0084] In the present invention, the term "wheat protein" is derived from wheat and is mainly composed of albumin, globulin, gliadin, and glutenin. Due to the extensibility of gliadin and the elasticity of glutenin, they can form a network structure with water, thus having excellent viscoelasticity, extensibility, water absorption, fat absorption and emulsification properties, film-forming properties, and unique physical properties such as a light and mellow fragrance or a slightly grainy taste.

[0085] In the present invention, the term "pea protein" is a high-protein raw material isolated from peas. Pea protein contains rich and typical legume amino acids, vitamins, and dietary fiber. Moreover, due to its lactose-free, cholesterol-free, low-calorie, relatively low bean odor, and low allergenicity, it is suitable for people with lactose intolerance, digestive disorders, and those who advocate vegetarianism.

[0086] The beneficial effects achieved by the present invention:

[0087] 1) The wetting speed of the protein powder described in the present invention does not exceed 100 seconds. After wetting and stirring, it can be quickly dispersed in water and is not easy to agglomerate. Its wetting speed can reach or even be better than the effect of mixing ungranulated soybean protein powder with an anti-caking agent. For example, after mixing ungranulated soybean protein powder with silicon dioxide, its wetting speed is 171 s. The protein powder described in the present invention can be directly applied without the need to compound an anti-caking agent.

[0088] 2) The protein powder of the present invention has good fluidity, can be filled into strip-packaged products in production applications, has a low content of fine particles, is not prone to powder scattering, and is not likely to have powder clamping at the sealing position, which affects the sealing.

[0089] 3) For the protein powder of the present invention, the binder is water, the degree of powder adhesion is moderate, there are sufficient pores between the powders to facilitate the entry of moisture and accelerate the wetting of the material, and the bonded particles are not so large in diameter that moisture cannot quickly enter the center of the particles. The moderate particle size can reduce the caking phenomenon caused by the static electricity between the fine powders.

[0090] 4) In addition to the test of the particle size distribution, the granulation end point can also be determined by combining the Carr index with the determination of the bulk density, which is convenient for actual production operations. Specific Embodiments

[0091] The following will describe the implementation schemes of the present invention in detail in conjunction with the embodiments. However, those skilled in the art will understand that the following embodiments are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention. For those not specified in the embodiments, they are carried out according to the conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified for the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0092] Example 1

[0093] Soybean protein isolate powder (commercially purchased, batch number R20230726) was put into a bottom-spray fluidized bed granulator (Syntegon, Solidlab2), and water was sprayed for granulation. The spray amount of water was 40 wt% of the total amount of soybean protein powder, the material temperature was 37 °C, the atomization pressure was 0.6 bar, and the liquid spraying speed was 18 g / min.

[0094] The obtained product was measured for particle size distribution (Malvern laser particle size analyzer MS-2000), bulk density, and Carr index (Baxter intelligent powder property tester BT-1001). The results are shown in Table 1.

[0095] Table 1

[0096] Particle size distribution d(0.5) Bulk density Carr's coefficient 54.6 μm 0.30 g / mL 23.3％

[0097] The obtained soybean protein powder in this example was tested for the wetting speed. The wetting speed measurement method was as follows: Prepare a beaker with a specification of 150 mL (the diameter of the cup body is 58 mm - 65 mm), and fill it with 100 mL of normal temperature water. Weigh 0.5 g of the soybean protein powder to be tested with weighing paper, pour it into the beaker at one time, and let it stand. Wait until all the particles are wetted, and record the required time. Test three times and take the average value. The result was 67 s. After wetting, it can be quickly dispersed in water after stirring and is not prone to caking.

[0098] Example 2

[0099] Put the soy protein isolate powder (commercially purchased, batch number R20230726) into a bottom-spray fluidized bed granulator (Syntegon, Solidlab2), and spray water for granulation. The spray amount of water is 40 wt% of the total amount of soy protein powder, the material temperature is 33 °C, the atomization pressure is 0.5 bar, and the liquid spraying speed is 23 g / min.

[0100] Measure the particle size distribution, bulk density, and Carr's coefficient of the obtained product, and the results are shown in Table 2.

[0101] Table 2

[0102] Particle size distribution d(0.5) Bulk density Carr's coefficient 59.5 μm 0.28 g / mL 25.0％

[0103] Test the wetting speed of the soy protein powder obtained in this example according to the method of Example 1, and take the average value after testing three times. The result is 41 s. After wetting, it can be quickly dispersed in water by stirring and is not easy to agglomerate.

[0104] Example 3

[0105] Put the soy protein isolate powder (commercially purchased, batch number R20230704) into a bottom-spray fluidized bed granulator (Syntegon, Solidlab2), and spray water for granulation. The spray amount of water is 40 wt% of the total amount of soy protein powder, the material temperature is 32 °C, the atomization pressure is 0.3 bar, and the liquid spraying speed is 30 g / min.

[0106] Measure the particle size distribution, bulk density, and Carr's coefficient of the obtained product, and the results are shown in Table 3.

[0107] Table 3

[0108] Particle size distribution d(0.5) Bulk density Carr's coefficient 77.4 μm 0.28 g / mL 19.2％

[0109] Test the wetting speed of the soy protein powder obtained in this example according to the method of Example 1, and take the average value after testing three times. The result is 100 s. After wetting, it can be quickly dispersed in water by stirring and is not easy to agglomerate.

[0110] Example 4

[0111] Put the composite plant protein powder (composed of rice protein and pea protein) (commercially purchased, batch number 20220923) into a top-spray fluidized bed granulator (Chuangzhi, FLZB-0.5), and spray water for granulation. The spray amount of water is 30 wt% of the total amount of the composite plant protein powder, the material temperature is 43 °C, the atomization pressure is 0.2 bar, and the liquid spraying speed is 11 g / min.

[0112] Measure the particle size distribution, bulk density, and Carr's coefficient of the obtained product, and the results are shown in Table 4.

[0113] Table 4

[0114]

[0115]

[0116] The composite plant protein powder obtained in this example was tested for wetting speed according to the method of Example 1. The test was carried out three times and the average value was taken, and the result was 89 s. After wetting, it can be quickly dispersed in water by stirring and is not easy to agglomerate.

[0117] Comparative Example 1

[0118] Soybean protein isolate (commercially purchased, batch number R20230704) was put into a top-spray fluidized bed granulator (Chongqing Ingle FL-200B), and water was sprayed for granulation. The spray amount of water was 30 wt% of the total amount of soybean protein powder, the material temperature was 50 °C, the atomization pressure was 0.2 bar, and the unit volume flow rate was 800 g / mL. The obtained product was measured for particle size distribution, bulk density, and Carr's coefficient, and the results are shown in Table 5.

[0119] Table 5

[0120] Particle size distribution d(0.5) Bulk density Carr's coefficient 49.1 μm 0.29 g / mL 31.0％

[0121] The obtained particles had a relatively small particle size and a relatively large Carr's coefficient, indicating poor fluidity. This shows insufficient granulation. The soybean protein powder obtained in this comparative example was tested for wetting speed according to the method of Example 1. The test was carried out three times and the average value was taken, and the result was 218 s.

[0122] Comparative Example 2

[0123] Soybean protein isolate (commercially purchased, batch number R20230704) was put into a bottom-spray fluidized bed granulator (Syntegon, Solidlab2), and water was sprayed for granulation. The spray amount of water was 40 wt% of the total amount of soybean protein powder, the material temperature was 35 °C, the atomization pressure was 0.3 bar, and the liquid spraying speed was 60 g / min.

[0124] The obtained product was measured for particle size distribution, bulk density, and Carr's coefficient, and the results are shown in Table 6.

[0125] Table 6

[0126] Particle size distribution d(0.5) Bulk density Carr's coefficient 90.4 μm 0.30 g / mL 8.8％

[0127] The obtained particles had a relatively large particle size and a relatively small Carr's coefficient. This shows that the granulation degree is too large and the formed particles are too large. The soybean protein powder obtained in this comparative example was tested for wetting speed according to the method of Example 1. The test was carried out three times and the average value was taken, and the result was 110 s.

[0128] Comparative Example 3

[0129] Put soy protein isolate powder (commercially purchased, batch number R20230704) into a bottom-spray fluidized bed granulator (Syntegon, Solidlab2), and spray water for granulation. The spraying amount of water is 40 wt% of the total amount of soy protein powder, the material temperature is 34 °C, the atomization pressure is 0.3 bar, and the liquid spraying speed is 75 g / min.

[0130] Measure the particle size distribution, bulk density, and Carr's coefficient of the obtained product, and the results are shown in Table 7.

[0131] Table 7

[0132] Particle size distribution d(0.5) Bulk density Carr's coefficient 101.6 μm 0.29 g / mL 12.4％

[0133] The particle size of the obtained particles is relatively large, and Carr's coefficient is relatively small. It indicates that the granulation degree is too large and the formed particles are too large. The wetting speed of the soy protein powder obtained in this comparative example was tested according to the method of Example 1, and the average value was taken after three tests, and the result was 123 s.

[0134] Comparative Example 4

[0135] Measure the particle size distribution, bulk density, and Carr's coefficient of 3 batches of soy protein isolate powder (commercially purchased), and test the wetting speed according to the method of Example 1, and the results are shown in Table 8.

[0136] Table 8

[0137]

[0138]

[0139] The particle size of the soy protein isolate powder without granulation is relatively small, the bulk density and Carr's coefficient are relatively large, and the wetting speed is very slow.

[0140] Comparative Example 5

[0141] Using soy protein isolate powder R20230704 as the raw material, after mixing with 0.2 wt% silica, measure the particle size distribution, bulk density, and Carr's coefficient, and the results are shown in Table 9.

[0142] Table 9

[0143] Particle size distribution d(0.5) Bulk density Carr's coefficient 48.7 μm 0.33 g / mL 22.8％

[0144] The wetting speed of the soy protein powder obtained in this comparative example was tested according to the method of Example 1, and the average value was taken after three tests, and the result was 171 s.

[0145] Comparative Example 6

[0146] The particle size distribution, bulk density, and Carr's coefficient of the composite plant protein powder (composed of rice protein and pea protein) (purchased commercially, batch number 20220923) were determined, and the wetting rate test was carried out according to the method of Example 1. The results are shown in Table 10.

[0147] Table 10

[0148] Particle size distribution d(0.5) Bulk density Carr's coefficient Wetting time 44.3 μm 0.31 g / mL 41.9％ 180s

[0149] The composite plant protein powder without granulation has poor fluidity, a large Carr's coefficient, and a very slow wetting rate.

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that it is still possible to modify the specific implementation manners of the present invention or perform equivalent replacements for some technical features; without departing from the spirit of the technical solutions of the present invention, they should all be covered within the scope of the technical solutions claimed by the present invention.

Claims

1. A protein powder, with the particle size distribution d(0.5) being 50 - 90 μm, preferably 52 - 85 μm, more preferably 53 - 80 μm, and even more preferably 54 - 78 μm; Preferably, the Carr's coefficient of the protein powder is 13% - 30%, preferably 16% - 28%, more preferably 18% - 26%, and even more preferably 19% - 25%; Preferably, the bulk density of the protein powder is 0.25 - 0.35 g / mL, preferably 0.27 - 0.32 g / mL, more preferably 0.28 - 0.30 g / mL; Preferably, the protein powder does not contain an anti-caking agent and / or phospholipids. Examples of the anti-caking agent include silica, tricalcium phosphate, magnesium stearate, calcium stearate, potassium stearate, microcrystalline cellulose, sodium pyrophosphate, sodium hexametaphosphate, ferric tartrate, carnauba wax, talc powder, calcium silicate, sodium acid pyrophosphate, calcium dihydrogen phosphate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, potassium hydrogen phosphate, calcium hydrogen phosphate, tripotassium phosphate, trisodium phosphate, sodium hexametaphosphate, sodium tripolyphosphate, sodium dihydrogen phosphate, disodium hydrogen phosphate, potassium pyrophosphate, sodium trimetaphosphate, potassium metaphosphate, calcium acid pyrophosphate, ammonium ferric citrate, magnesium carbonate, phosphoric acid, sodium pyrophosphate, calcium acid pyrophosphate, and polyglycerol fatty acid esters.

2. The protein powder according to claim 1, which is prepared from a protein powder raw material and water by a fluidized bed granulator (such as a top spray or bottom spray fluidized bed granulator). Preferably, the protein powder raw material is selected from one or more of milk protein, whey protein, casein, soy protein, soy protein isolate, rice protein, wheat protein, and pea protein. More preferably, the protein powder raw material is selected from one or more of soy protein isolate, rice protein, and pea protein.

3. The protein powder according to claim 1 or 2, which is prepared by a method comprising the following steps: (1) Feed the protein powder raw material into a fluidized bed granulator, (2) Spray water for granulation; Preferably, the protein powder raw material is selected from one or more of milk protein, whey protein, casein, soy protein, soy protein isolate, rice protein, wheat protein, and pea protein. More preferably, the protein powder raw material is selected from one or more of soy protein isolate, rice protein, and pea protein; Preferably, the fluidized bed granulator is a top spray or bottom spray fluidized bed granulator; Preferably, in step (2), the water spraying speed is 3 - 55 g / min, preferably 5 - 45 g / min, more preferably 8 - 38 g / min, and even more preferably 11 - 30 g / min; Preferably, step (2) has one or more of the following technical features: a) The spray amount of water is 20wt% - 60wt% of the total amount of the protein powder raw material, preferably 25wt% - 50wt%, more preferably 30wt% - 40wt%, b) The material temperature is controlled at 30 - 50 °C, preferably 32 - 43 °C, c) The atomization pressure is 0.1 - 0.6 bar, preferably 0.2 - 0.6 bar.

4. A method for preparing the protein powder according to any one of claims 1 - 3, comprising: (1) Feed the protein powder raw material into a fluidized bed granulator. (2) Spray water for granulation.

5. The method according to claim 4, wherein, The protein powder raw material is selected from one or more of milk protein, whey protein, casein, soy protein, soy protein isolate, rice protein, wheat protein, and pea protein. Preferably, the protein powder raw material is selected from one or more of soy protein isolate, rice protein, and pea protein.

6. The method according to claim 4 or 5, wherein, The fluidized bed granulator is a top-spray or bottom-spray fluidized bed granulator.

7. The method according to any one of claims 4 to 6, wherein, In step (2), the water spraying speed is 3 - 55 g / min, preferably 5 - 45 g / min, more preferably 8 - 38 g / min, and even more preferably 11 - 30 g / min.

8. The method according to any one of claims 4 to 7, wherein Step (2) has one or more of the following technical features: a) The spraying amount of water is 20 wt% - 60 wt% of the total amount of the protein powder raw material, preferably 25 wt% - 50 wt%, and more preferably 30 wt% - 40 wt%. b) The material temperature is controlled at 30 - 50 °C, preferably 32 - 43 °C. c) The atomization pressure is 0.1 - 0.6 bar, preferably 0.2 - 0.6 bar.

9. A composition comprising the protein powder according to any one of claims 1 - 3. Preferably, it further comprises nutrients such as calcium, iron, zinc, and / or various vitamins (such as vitamin A, vitamin B1, vitamin B2, niacin, pantothenic acid, vitamin B6, biotin, folic acid, vitamin B12, vitamin C, vitamin D, vitamin E, and vitamin K).

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