Dispersible soy protein and method for preparing the same

Abstract

The application provides a kind of dispersed soy protein and its preparation method, soy protein granulation is used, and the temperature is kept at 55-75 DEG C for 1-10h, and the dispersed soy protein is obtained, wherein, when 12.5wt% soy protein aqueous solution is formed by soy protein, the pH value of the soy protein aqueous solution is 6.5-7.3.The application also discloses a kind of instant powder and fluid food containing the dispersed soy protein, using the technical scheme, by adjusting the pH value of soy protein before granulation, and keeping warm after completing granulation can significantly improve the viscosity and dispersibility of soy protein.

Description

Technical Field

[0001] This invention relates to the field of proteins, and more particularly to a dispersible soy protein isolate and its preparation method. Background Technology

[0002] Soy protein isolate is a food ingredient obtained from low-temperature defatted soybean meal through processing. As a high-quality plant protein resource, soy protein is increasingly used across various industries. Soy protein is a plant-based protein with an amino acid composition similar to milk protein. Except for a slightly lower level of methionine, it is rich in all other essential amino acids, making it a complete plant-based protein. Nutritionally, it is comparable to animal protein, and its genetic structure is closest to that of human amino acids, making it one of the most nutritious plant proteins. Due to its high nutritional value, soy protein is increasingly used in various nutritional and health foods. Protein powder is one of the most important products in this category. Since this product is instant, it needs to be prepared quickly without clumping, a characteristic of soy protein that is highly dispersible.

[0003] The traditional processing method for soy protein isolate is as follows: White soybean flakes are dissolved in alkaline water to extract soy protein, as natural soy protein dissolves more readily under alkaline conditions. After centrifugation, a supernatant protein solution is obtained, and the pH of the solution is adjusted to around 4.5 to precipitate the protein, as soy protein has the lowest solubility at pH 4.5. This is achieved through centrifugation. The protein solution is then neutralized and the pH is adjusted to neutral. Next, it undergoes sterilization to kill microorganisms. Finally, it is spray-dried to obtain the powdered soy protein isolate product. Soy protein isolate prepared using traditional methods has gelling and emulsifying properties, but it has high viscosity, poor dispersibility, and tends to clump when dissolved in water.

[0004] Reference 1 (CN111587947A) describes a preparation process for highly dispersible and stable soy protein isolate. This process mainly employs enzyme modification combined with microwave radiation modification to ultimately improve the dispersibility and stability of the product.

[0005] References 2 (CN107873942A) and 3 (CN106798072A) both disclose a process for preparing highly dispersible soy protein isolate. This process uses a traditional soy protein isolate preparation process, obtaining highly dispersible soy protein isolate through spray drying and gel coating.

[0006] Reference 4 (Zhao Jiang, Zhang Zesheng, Wang Hao, et al. Optimization study on protein powder production process using fluidized bed sprayed lecithin granulation technology [J]. Food Research and Development, 2007, 28(4):4.) discloses a process for producing protein powder using fluidized bed sprayed lecithin granulation technology, which can effectively improve the dispersibility of soybean protein. Summary of the Invention

[0007] Current technologies primarily focus on the dispersibility of soybean protein. However, viscosity is an important functional property in liquid foods such as beverages, soups, and sauces, especially for domestic consumers who prefer a higher viscosity and a thicker, more substantial texture.

[0008] Therefore, how to provide a soybean protein with improved dispersibility and high viscosity has become a technical problem that urgently needs to be solved in this field.

[0009] Based on the above-mentioned technical problems, the inventors of this invention have discovered that by controlling the pH value of soybean protein before granulation and keeping the granulated soybean protein powder at a specific temperature range, soybean protein with further improved dispersibility and high viscosity can be obtained.

[0010] In a first aspect, the present invention provides a method for preparing dispersed soy protein, comprising granulating soy protein and holding it at 55-75°C for 1-10 hours to obtain dispersed soy protein.

[0011] Specifically, when soybean protein forms a 12.5wt% soybean protein aqueous solution, the pH value of the soybean protein aqueous solution is 6.5-7.3.

[0012] In one or more specific embodiments, the temperature of the heat preservation step is 60-70°C, preferably 60-65°C.

[0013] In one or more specific embodiments, when the soybean protein forms a 12.5 wt% aqueous solution, the pH of the aqueous solution is 6.5-7.0.

[0014] In one or more specific embodiments, the soy protein is soy protein isolate.

[0015] In one or more specific embodiments, the soybean protein is granulated using fluidized bed granulation.

[0016] In one or more specific embodiments, water or an aqueous solution of phospholipids is used as the granulation liquid in the fluidized bed granulation step.

[0017] In one or more specific embodiments, soy protein is prepared by the following methods, including:

[0018] Defatted soybean meal was dissolved in alkali and precipitated with acid to obtain acidic soybean protein;

[0019] Dissolve the acidic soy protein and adjust the pH.

[0020] Sterilization;

[0021] Soy protein is obtained by spray drying.

[0022] In a second aspect, the present invention provides a dispersible soybean protein prepared by any of the foregoing methods.

[0023] A third aspect of the present invention provides an instant powder comprising any of the aforementioned dispersible soy proteins.

[0024] A fourth aspect of the present invention provides a liquid food comprising any of the aforementioned dispersible soy protein or instant powder. Detailed Implementation

[0025] It should be understood that, within the scope of this invention, the above-described technical features of this invention and the technical features specifically described below (such as embodiments) can be combined with each other to form preferred technical solutions.

[0026] In a first aspect, the present invention provides a method for preparing dispersed soy protein, comprising granulating soy protein and holding it at 55-75°C for 1-10 hours to obtain dispersed soy protein.

[0027] Specifically, when soybean protein forms a 12.5wt% soybean protein aqueous solution, the pH value of the soybean protein aqueous solution is 6.5-7.3.

[0028] This technical solution significantly improves the viscosity and dispersibility of soybean protein by adjusting the pH value of soybean protein before granulation and by keeping it warm after granulation.

[0029] Furthermore, the pH value of the soy protein before granulation can be adjusted during the soy protein preparation process, or it can be adjusted by directly resolving commercially available soy protein powder.

[0030] In one or more specific embodiments, soy protein is prepared by the following methods, including:

[0031] (1) Defatted soybean meal was dissolved in alkali and precipitated with acid to obtain acidic soybean protein;

[0032] (2) Dissolve the acidic soybean protein, adjust the pH, remove the precipitate, and take the supernatant;

[0033] (3) Sterilization;

[0034] (4) Spray drying yields soybean protein.

[0035] The pH is adjusted during the preparation of soy protein so that when the spray-dried soy protein forms a 12.5wt% soy protein aqueous solution, the pH value of the soy protein aqueous solution is 6.5-7.3.

[0036] In this technical solution, the alkali dissolution and acid precipitation steps can use pH adjusters commonly used in food processing. Acidic pH adjusters include hydrochloric acid and citric acid, while alkaline pH adjusters include sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0037] Preferably, in step (1), a certain amount of defatted soybean meal is dispersed in water under alkaline conditions, and solid-liquid separation is performed. The supernatant is collected, the pH of the supernatant is adjusted to near the isoelectric point of soybean protein, and solid-liquid separation is performed. The resulting precipitate is acidic soybean protein.

[0038] Alternatively, a certain amount of defatted soybean meal is dispersed in water under alkaline conditions, and solid-liquid separation is performed. The first supernatant and the first precipitate are collected, and the first precipitate is dispersed in water again for solid-liquid separation. The second supernatant and the second precipitate are collected, and the first and second supernatants are mixed. The mixed supernatant is adjusted to be close to the isoelectric point of soybean protein, and solid-liquid separation is performed. The precipitate obtained is acidic soybean protein.

[0039] Preferably, a certain amount of defatted soybean meal is taken and dispersed in 7 times its volume of 50°C warm water, stirred evenly, and the pH of the solution is adjusted to 7.5 with 10% sodium hydroxide solution, and stirred for 30 minutes. Centrifugation is performed, and the first supernatant and first precipitate are collected. 5 times its volume of 50°C warm water is added to the first precipitate, and the mixture is stirred for 5 minutes. Centrifugation is performed, and the second supernatant is collected. The second supernatant obtained in this step is mixed evenly with the first supernatant. The pH of the supernatant solution is adjusted to 4.5 with 1 mol / L hydrochloric acid. Centrifugation is performed, and the precipitate is collected to obtain acid-soluble soybean protein.

[0040] Preferably, in step (2), acidic soybean protein is uniformly dispersed in cold water at 15°C, and the solid content of the solution is adjusted to 10-15 wt%. The pH of the above solution is adjusted to about 6.5-7.3 using 10 wt% sodium hydroxide solution.

[0041] In one or more specific implementations, the prepared soy protein product, such as commercially available soy protein, can be dissolved again, the pH value adjusted, and then spray-dried to obtain soy protein with a pH value that meets the requirements.

[0042] In this invention, to improve the viscosity and dispersibility of soybean protein, the granulated product is kept at 55-75℃ for 1-10 hours. Temperatures that are too high or too low will reduce the improvement effect. Preferably, the holding temperature is 60-70℃, and more preferably, it is 60-65℃.

[0043] Furthermore, the pH value before granulation also affects the final viscosity and dispersibility of soy protein. Too high a pH will simultaneously reduce both the viscosity and dispersibility of soy protein, while too low a pH will significantly reduce its viscosity. Therefore, when soy protein forms a 12.5 wt% aqueous solution, the pH value of the aqueous solution should be 6.5-7.3, preferably 6.5-7.0.

[0044] In this invention, there is no particular limitation on the type of soy protein. Known soy proteins, such as soy protein concentrate and soy protein isolate, can be used. It is foreseeable that the method of this invention can effectively improve the dispersibility and viscosity of various commercially available soy protein products with soy protein as the main component.

[0045] Preferably, the soy protein is soy protein isolate.

[0046] Furthermore, there are no specific restrictions on the granulation method of soybean protein, but fluidized bed granulation is preferred.

[0047] In one or more specific embodiments, water or an aqueous solution of phospholipids is used as the granulation liquid in the fluidized bed granulation step.

[0048] Furthermore, when using phospholipids, an appropriate amount of oil can be added to adjust the HLB value of the phospholipids and further improve the product dispersibility. Preferably, the weight ratio of phospholipids to oil is 1:0.5 to 2. There are no special limitations on the type of oil, which can be selected from one or more vegetable oils, such as soybean oil, sunflower seed oil, rapeseed oil, etc. Preferably, it is soybean oil.

[0049] Furthermore, the total concentration of phospholipids and oils can be 0.1–5 wt%, more preferably 0.2–3 wt%, and most preferably 0.7–1.5 wt%.

[0050] In a second aspect, the present invention provides a dispersible soybean protein prepared by any of the foregoing methods.

[0051] A third aspect of the present invention provides a reconstituted powder comprising any of the aforementioned dispersible soy proteins. Specific examples of reconstituted powders include meal replacement powders, seasonings, protein powders, nutritional powders, beverage powders, etc.

[0052] A fourth aspect of the present invention provides a liquid food comprising any of the aforementioned dispersed soy protein or instant powder. Specific examples of liquid foods include soups, sauces, pastes, and liquid foods.

[0053] Detection method:

[0054] (1) Dispersibility: Weigh 150g of warm water (45-50℃) into a 400ml beaker, and separately weigh 12g of the finished product powder, pour it into the warm water, and stir with a glass rod for 1 minute at a stirring speed of 200rpm. After stirring, pass the solution through a 25-mesh sieve, blot the residue on the sieve with filter paper, and weigh the residue on the sieve, m. The value of m indicates the quality of product dispersibility. The smaller the value of m, the better the dispersibility.

[0055] (2) Viscosity: Weigh 150g of room temperature water (15-25℃) into a 400ml beaker, place the beaker on a magnetic stirrer, and put the magnetic rotor into the beaker. Separately weigh 12g of the finished powder, and while stirring (stirring speed 400rpm), pour the protein powder into the water. If there are clumps of protein particles, break them up with a spoon, stir for 1 minute, and check the viscosity. Use a No. 62 rotor at a speed of 100rpm.

[0056] Sources of raw materials:

[0057] Defatted soybean meal: Qinhuangdao Jinhai Food Industry Co., Ltd.

[0058] Phospholipids: Qinhuangdao Jinhai Food Industry Co., Ltd.

[0059] Example 1

[0060] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate, add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Take the precipitate and disperse it evenly in 15℃ cold water, adjusting the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, this is the neutralized solution. Quickly sterilize the above solution at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is pneumatically fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in sprayed protein powder B. The sprayed protein powder B is then pneumatically transported (at 60°C) to a temporary storage tank and kept at that temperature for 5 hours. The final product, dispersed soy protein, is obtained.

[0061] Example 2

[0062] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. To prepare the granulation solution, soybean concentrated lecithin and soybean oil were mixed at a ratio of 0.5:0.5. This mixture was then further mixed with water at a ratio of 1:99 to obtain granulation solution B. The resulting protein powder A was then pneumatically fed into a fluidized bed granulator, and granulation solution B was sprayed onto the surface of the protein powder. The protein powder remained in the granulator for 15 minutes. The resulting coated protein powder was then pneumatically conveyed (at 60°C) to a temporary storage tank and kept at that temperature for 5 hours. This yielded the final product, dispersed soybean protein.

[0063] Example 3

[0064] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant obtained from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is pneumatically fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in sprayed protein powder B. The sprayed protein powder B is then pneumatically transferred (at 75°C) to a temporary storage tank and kept at that temperature for 6 hours. The final product, dispersed soy protein, is obtained.

[0065] Example 4

[0066] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant obtained from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 6.8 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is pneumatically fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in sprayed protein powder B. The sprayed protein powder B is then pneumatically transferred (at 75°C) to a temporary storage tank and kept at that temperature for 6 hours. The final product, dispersed soy protein, is obtained.

[0067] Example 5

[0068] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant obtained from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 6.6 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is pneumatically fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in sprayed protein powder B. The sprayed protein powder B is then pneumatically transferred (at 75°C) to a temporary storage tank and kept at that temperature for 6 hours. The final product, dispersed soy protein, is obtained.

[0069] Example 6

[0070] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant obtained from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in coated protein powder B. The coated protein powder B is then pneumatically transferred (at 55°C) to a temporary storage tank and kept at that temperature for 6 hours. The final product, dispersed soy protein, is obtained.

[0071] Example 7

[0072] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.3 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, this is the neutralized solution. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is pneumatically fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in sprayed protein powder B. The sprayed protein powder B is then pneumatically transferred (at 75°C) to a temporary storage tank and kept at that temperature for 6 hours. The final product, dispersed soy protein, is obtained.

[0073] Comparative Example 1

[0074] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder.

[0075] Comparative Example 2

[0076] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.5 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder.

[0077] Comparative Example 3

[0078] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.8 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, this is the neutralized solution. Quickly sterilize the above solution at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder.

[0079] Comparative Example 4

[0080] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 8.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder.

[0081] Comparative Example 5

[0082] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. To prepare the granulation solution, soybean concentrated lecithin and soybean oil were mixed at a ratio of 0.5:0.5. This mixture was then further mixed with water at a ratio of 1:99 to obtain granulation solution B. Protein powder A was then pneumatically fed into a granulator, and granulation solution B was sprayed onto the surface of protein powder A. The spraying amount was 0.1% (the proportion of granulation solution to protein powder), and the residence time of the protein powder in the granulator was 15 minutes. The resulting coated protein powder was then obtained.

[0083] Comparative Example 6

[0084] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, this is the neutralized solution. Quickly sterilize the above solution at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder from the first step. The protein powder resides in the granulator for 15 minutes. The resulting coated protein powder is then obtained.

[0085] Comparative Example 7

[0086] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, the neutralized solution is obtained. Sterilize the above solution rapidly at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. The obtained protein powder A is pneumatically conveyed (at a temperature of 60°C) to a temporary storage tank and kept at that temperature for 5 hours. The final product, soy protein isolate, is obtained.

[0087] Comparative Example 8

[0088] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Take the precipitate and disperse it evenly in 15℃ cold water, adjusting the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.5 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, this is the neutralized solution. Quickly sterilize the above solution at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. The obtained protein powder A is pneumatically conveyed (at a temperature of 60°C) to a temporary storage tank and kept at that temperature for 5 hours. The final product, soy protein isolate, is obtained.

[0089] Comparative Example 9

[0090] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.5 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, this is the neutralized solution. Quickly sterilize the above solution at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in coated protein powder B. The coated protein powder B is then pneumatically transferred (at 75°C) to a storage tank and kept at that temperature for 6 hours. The final product, soy protein isolate, is obtained.

[0091] Comparative Example 10

[0092] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 6.4 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, this is the neutralized solution. Quickly sterilize the above solution at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in coated protein powder B. The coated protein powder B is then pneumatically transferred (at 75°C) to a storage tank and kept at that temperature for 6 hours. The final product, soy protein isolate, is obtained.

[0093] Comparative Example 11

[0094] Take a certain amount of defatted soybean meal, disperse it in 7 times its volume of 50℃ warm water, stir evenly, adjust the pH of the solution to 7.5 with 10% sodium hydroxide solution, and stir for 30 min. Centrifuge at 3300g for 5 min. Collect the supernatant and precipitate separately. Add 5 times its volume of defatted soybean meal in 50℃ warm water to the precipitate, stir for 5 min, and centrifuge at 3300g for 5 min. Collect the supernatant and mix it evenly with the supernatant from the previous centrifugation. Adjust the pH of the supernatant to 4.5 with 1mol / L hydrochloric acid. Centrifuge at 3300g for 5 min. Disperse the precipitate evenly in 15℃ cold water and adjust the solid content of the solution to 12.5%. Adjust the pH of the above solution to 7.0 with 10% (w / w) sodium hydroxide. After the precipitate has completely dissolved, this is the neutralized solution. Quickly sterilize the above solution at 145℃ for 15 s. Finally, spray dry to obtain dried protein powder A. Prepare granulation solution and pure water. The obtained protein powder A is pneumatically fed into a fluidized bed granulator, and pure water is sprayed onto the surface of the protein powder. The protein powder resides in the granulator for 15 minutes, resulting in sprayed protein powder B. The sprayed protein powder B is then pneumatically transported (at 50°C) to a temporary storage tank and kept at that temperature for 4 hours. The final product, soy protein isolate, is obtained.

[0095] Table 1. Process conditions and performance of the examples and comparative examples

[0096]

[0097]

[0098] As shown in Table 1 above, Examples 1-7 prepared using the method of the present invention all achieved good dispersibility and viscosity, with dispersibility ≤1g and viscosity ≥75mPa.s. Furthermore, the granulation using pure water in Example 1 achieved comparable or even better dispersibility and viscosity than the granulation using phospholipids in Example 2.

[0099] The soybean protein powders in Comparative Examples 1-4 that were not granulated or insulated showed very poor dispersibility, and although the viscosity increased with increasing pH, the dispersibility further deteriorated.

[0100] Comparative Examples 5 and 6 used phospholipids and pure water as granulation solutions, respectively. Although the dispersibility and viscosity were improved to some extent, there was still a significant difference compared to Examples 1-6.

[0101] In Comparative Examples 7 and 8, the soybean protein was subjected to heat preservation treatment, which also improved its dispersibility and viscosity, but there was still a significant difference compared to Examples 1-7.

[0102] In Comparative Example 9, excessively high pH caused a simultaneous decrease in both viscosity and dispersibility, while in Comparative Example 10, excessively low pH caused a significant decrease in viscosity.

[0103] In Comparative Example 11, the insulation temperature was too low, resulting in a significant decrease in viscosity and dispersibility compared to Example 3.

[0104] The descriptions of the exemplary embodiments presented above are merely illustrative of the technical solutions of the present invention and are not intended to be exhaustive or to limit the invention to the precise forms described. Obviously, those skilled in the art can make many changes and variations based on the above teachings. The exemplary embodiments were chosen and described to explain the specific principles of the invention and its practical applications, thereby enabling other those skilled in the art to understand, implement, and utilize the various exemplary embodiments of the invention and their various alternatives and modifications. The scope of protection of the present invention is intended to be defined by the appended claims and their equivalents.

Claims

1. A method for preparing dispersible soybean protein, characterized in that, Includes the following steps: The dispersed soybean protein was obtained by granulation of soybean protein and incubation at 55-75℃ for 1-10 hours. The pH value of the soybean protein when forming a 12.5wt% soybean protein aqueous solution is 6.5-7.

3.

2. The method for preparing dispersible soybean protein as described in claim 1, characterized in that, The temperature during the heat preservation step is 60-70℃.

3. The method for preparing dispersible soybean protein as described in claim 2, characterized in that, The temperature during the heat preservation step is 60-65℃.

4. The method for preparing dispersible soybean protein as described in claim 1, characterized in that, The pH value of the soybean protein when forming a 12.5wt% soybean protein aqueous solution is 6.5-7.

0.

5. The method for preparing dispersible soybean protein as described in claim 1, characterized in that, The soy protein mentioned is soy protein isolate.

6. The method for preparing dispersible soybean protein according to any one of claims 1-5, characterized in that, The soybean protein was granulated using a fluidized bed granulation process.

7. The method for preparing dispersible soybean protein as described in claim 6, characterized in that, In the boiling granulation step, water or phospholipid aqueous solution is used as the granulation liquid.

8. The method for preparing dispersible soybean protein according to any one of claims 1-5, characterized in that, The soy protein is prepared by the following methods, including: Defatted soybean meal was dissolved in alkali and precipitated with acid to obtain acidic soybean protein; Dissolve the acidic soybean protein and adjust the pH. Sterilization; The soybean protein was obtained by spray drying.

9. A dispersible soybean protein prepared by any one of claims 1-8.

10. A type of instant powder, characterized in that, Includes the dispersed soy protein as described in claim 9.

11. A liquid food product, characterized in that, Includes the dispersible soy protein of claim 9 or the instant powder of claim 10.

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