Soy protein preparation method

Abstract

The present invention relates to a method for preparing soybean protein, which includes a method for treating soybean protein concentrate. The method includes: a step of forming a dispersion system to form the soybean protein concentrate into a dispersion system, wherein the dispersion system includes a nonionic surfactant with a specific HLB value, the amount of the nonionic surfactant is 0.15-2% by mass based on the dry weight of the soybean protein concentrate, and the pH value of the dispersion system is 3.0-6.5 or less; and a step of heating the dispersion system.

Description

Technical Field

[0001] The present invention belongs to the field of food, and mainly relates to a method for preparing plant protein, more specifically, to a method for preparing soybean protein, and especially to a method for modifying and treating alcohol-processed soybean protein. Background Art

[0002] Soy protein products are an important source of protein for organisms and are widely used in food. The main soy protein products include soy protein isolate and soy protein concentrate.

[0003] Soy protein isolate is a food ingredient obtained through processing of low-temperature desolvated soybean meal. Its protein content is ≥90% and it exhibits good functionality (gelling, foaming, emulsifying, and water and oil retention). However, the production of soy protein isolate typically involves an alkali dissolution and acid precipitation separation and extraction process. This generates significant wastewater, resulting in a darker product color and a distinct beany odor, limiting its application in food.

[0004] On the other hand, for soy protein concentrate, the main method is ethanol extraction, which does not produce wastewater and the ethanol can be reused, without causing environmental pollution. At the same time, the protein concentrate produced by the alcohol method is lighter in color and has a light flavor. However, the protein content of the protein concentrate produced by the alcohol method can only reach 65% to 72%, and the functionality of the product after ethanol denaturation is very poor, which limits its scope of application.

[0005] Furthermore, in order to improve the functionality and protein content of alcohol-processed soy protein concentrate, predecessors have conducted research on physical methods, chemical methods and enzymatic hydrolysis.

[0006] Reference 1 discloses a method for modifying alcohol-processed soybean protein concentrate, which comprises mixing soybean protein concentrate produced by the alcohol process with hot water at 50 to 100°C and adjusting the pH value to between 7 and 10; then placing the protein concentrate in a high-frequency electromagnetic field for modification; and finally homogenizing the modified protein slurry to improve the functionality and nutritional value of the product.

[0007] In cited document 2, alcohol-processed soy protein concentrate is prepared into an alkaline (pH 8-13) aqueous solution, which is then heated to no more than 90° C., and then the soy protein concentrate aqueous solution is ultrasonically treated to improve the solubility and functionality of the alcohol-processed soy protein concentrate.

[0008] Cited document 3 uses hydrothermal (60-140°C) treatment on alcohol-processed soybean protein concentrate obtained by low-temperature vacuum drying, and then adjusts it to acidic conditions and then to central conditions to obtain a protein dispersion, and then uses high-temperature sterilization and spray drying.

[0009] Reference 4 extracts soybean protein concentrate by ethanol extraction and distillation, then refolds the protein solution in a stacker (40-60°C) after homogenization, and finally obtains functional soybean protein concentrate by sterilization, deodorization, and high-pressure homogenization drying.

[0010] Reference 5 uses enzymatic hydrolysis technology in a step-by-step manner to improve the solubility of soybean protein concentrate, wherein cellulase, neutral protease or trypsin are used to enzymatically hydrolyze the alcohol-based soybean protein concentrate, and finally homogenization and spray drying are performed.

[0011] In cited document 6, the pH value of the soy protein concentrate aqueous solution is adjusted to 9-11 and dispersed evenly. Then, the alcohol-based protein concentrate is modified by a treatment method including a primary homogenization, a flash evaporation at a temperature of 120-160°C, and a secondary homogenization to obtain a product that can be used to replace soy protein isolate.

[0012] Reference 7 provides a method for producing high-gel, water-holding soy protein concentrate. Using alcohol-processed soy protein concentrate as the raw material, the powdered soy protein concentrate is produced through high-pressure homogenization, high-temperature instantaneous heating, flash evaporation, cooling, and spray drying. The pH value during high-pressure homogenization is controlled at 3-4, and the high-temperature instantaneous heating is controlled at 90-140°C for 5-20 seconds.

[0013] Thus, high-temperature heat treatment and pH adjustment are common methods for improving the functionality of alcohol-based protein concentrates, and their industrial operation is relatively simple. However, although modification methods such as the above-mentioned alcohol-based protein concentrates have been attempted in the art, there is still room for improvement in the functional modification of alcohol-based protein concentrates.

[0014] References:

[0015] Reference 1: CN1802984A

[0016] Reference 2: CN1802984A

[0017] Reference 3: CN101372501A

[0018] Reference 4: CN102396642A

[0019] Reference 5: CN102669407B

[0020] Reference 6: CN105685367A

[0021] Reference 7: CN108125014A Summary of the Invention

[0022] Problems to be solved by the invention

[0023] As mentioned above, in the prior art, heating (high temperature) treatment seems to be a natural means for the processing of soy protein concentrate, especially for the subsequent processing of soy protein concentrate obtained by the alcohol process, because it is believed that heating treatment can restore the alcohol denaturation caused by the soy protein concentrate obtained by the alcohol process, thereby improving the solubility of the protein. However, the inventors of the present invention have also found in their long-term research that the functionality (such as solubility, foaming and emulsification properties, etc.) of the (alcohol process) soy protein concentrate modified by high temperature heat treatment or the soy protein isolate product prepared therefrom decays rapidly during storage, resulting in poor storage stability, which seriously affects the application effect.

[0024] In addition, although some existing technologies use instantaneous heating methods to alleviate the impact of high-temperature treatment on soybean protein, they do not fundamentally alleviate the occurrence of the above-mentioned problems.

[0025] Therefore, based on the above-mentioned defects in the processing of soy protein concentrate in the prior art, especially the soy protein concentrate obtained by the alcohol method, the technical problem to be solved by the present invention is to provide an improved method for preparing soy protein. The soy protein treated by the method of the present invention, especially the soy protein concentrate obtained by the alcohol method, has further improved solubility, foaming and emulsification properties, and also shows improved storage stability.

[0026] Solutions for solving problems

[0027] After long-term research, it is found that the above technical problems can be solved by implementing the following technical solutions:

[0028] [1] The present invention first provides a method for processing soybean protein concentrate, wherein the method comprises:

[0029] The step of forming a dispersion system to form the soybean protein concentrate into a dispersion system, wherein the dispersion system includes a nonionic surfactant,

[0030] The HLB value of the nonionic surfactant is 7 to 14, and the amount thereof is 0.15 to 2.5% by mass based on the dry weight of the soy protein concentrate, and the pH value of the dispersion system is 3.0 to 6.5;

[0031] The step of heat treatment is to heat the dispersed system.

[0032] [2] The method according to [1], wherein the soybean protein concentrate comprises soybean protein concentrate extracted by alcohol method.

[0033] [3] The method according to [1] or [2], wherein, in the step of forming a dispersion system, the content of the soybean protein concentrate in the dispersion system is 1 to 20% by mass based on the dry weight of the soybean protein concentrate.

[0034] [4] The method according to any one of [1] to [3], wherein the step of forming the dispersion system is carried out at room temperature.

[0035] [5] The method according to any one of [1] to [4], wherein, in the step of forming a dispersion system, the HLB value of the nonionic surfactant is 9 to 12.

[0036] [6] The method according to any one of [1] to [5], wherein, in the step of forming a dispersion system, the nonionic surfactant includes one or more of a fatty alcohol polyoxyalkylene ether surfactant, a fatty acid polyoxyalkylene ester surfactant, and an acrylic acid polyoxyalkylene ester surfactant.

[0037] [7] The method according to any one of [1] to [6], wherein the pH value of the dispersion system in the step of forming the dispersion system is 4.0 to 6.0.

[0038] [8] The method according to any one of [1] to [7], wherein in the heating step, the heating temperature is not more than 150°C and the heating time is not more than 90 seconds.

[0039] [9] The method according to any one of [1] to [8], wherein in the heating step, the heating rate is not less than 30°C / s.

[0040]

[10] The method according to any one of [1] to [9], wherein the heating treatment step further includes at least one post-treatment step selected from the group consisting of a cooling step, a pH adjustment step, a centrifugal treatment step, a homogenization step, and a sterilization step.

[0041]

[11] . The present invention further provides a method for preparing soy protein (isolate), the method comprising:

[0042] a step of modifying the soy protein concentrate, wherein the soy protein concentrate is treated according to the method described in any one of [1] to

[10] to obtain a modified soy protein concentrate;

[0043] The enzymatic hydrolysis step is to enzymatically hydrolyze the modified soybean protein concentrate to obtain the soybean protein.

[0044]

[12] The method according to

[11] , wherein the protein content of the soybean protein is 90% by mass or more.

[0045]

[13] . In addition, the present invention also relates to a method for preparing a soybean protein product, wherein the method comprises the method described in any one of [1] to

[12] above.

[0046]

[14] . In addition, the present invention also relates to a soy protein product prepared according to any of the above methods.

[0047]

[15] . In addition, the present invention also relates to a food, characterized in that it comprises a product obtained by the method described in any one of [1] to

[13] above or comprises the soy protein product described in

[14] above.

[0048] Effects of the Invention

[0049] By implementing the above technical solution, the present invention can achieve the following technical effects:

[0050] 1) The soy protein concentrate processing method provided by the present invention can effectively solve the problems of short storage period and rapid functional decline of functional soy protein products prepared with concentrated soy protein, especially alcohol-processed concentrated soy protein as raw material, and the storage stability can also be significantly improved.

[0051] 2) By enzymatically hydrolyzing the product obtained by the soy protein concentrate processing method of the present invention, a soy protein with a protein content of more than 90% by mass can be further obtained, and the soy protein also has excellent solubility, foaming properties and storage stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 :The process flow in a specific embodiment of the present invention DETAILED DESCRIPTION

[0053] The following is a detailed description of the present invention. The following description of the technical features is based on representative embodiments and specific examples of the present invention, but the present invention is not limited to these embodiments and specific examples. It should be noted that:

[0054] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoints A and B.

[0055] In this specification, the numerical range expressed using "above" or "below" means a numerical range including the number.

[0056] In this specification, the use of "may" includes both the meaning of performing a certain process and the meaning of not performing a certain process.

[0057] In this specification, the use of "optional" or "optional" indicates that certain substances, components, execution steps, application conditions and other factors are used or not used.

[0058] In this specification, the term "room temperature" refers to an indoor ambient temperature of "18 to 30°C".

[0059] In this specification, the unit names used are all international standard unit names, and unless otherwise stated, the "%" used means weight or mass percentage.

[0060] In this specification, the use of "substantially" means that the standard deviation from a theoretical model or theoretical data is within a range of 5%, preferably 3%, and more preferably 1%.

[0061] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "embodiments," etc., mean that the specific elements (e.g., features, structures, properties, and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not be present in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0062] The present invention primarily provides a method for modifying soybean protein concentrate. By adding a specific amount of non-ionic surfactant under certain conditions, the adverse effects of the heat treatment step on the soybean protein can be reduced or alleviated, thereby improving the usability and storage stability of the final soybean protein product.

[0063] <First Aspect>

[0064] In a first aspect of the present invention, a method for processing soybean protein concentrate is provided, which mainly comprises the steps of forming a dispersed system containing the concentrated protein, a heat treatment step, and optionally other post-treatment steps after the heat treatment step.

[0065] Soy protein concentrate (SPC) is an environmentally friendly, light-flavored protein product produced by removing non-protein components from defatted soybean meal. There are three common processes for preparing SPC: wet heat washing, dilute acid washing, and alcohol extraction.

[0066] In principle, there is no particular limitation on the soybean protein concentrate in the present invention. However, it has been unexpectedly discovered that the method for treating the soybean protein concentrate of the present invention is particularly suitable for soybean protein concentrate obtained by the alcohol process.

[0067] Furthermore, in principle, there is no particular limitation on the composition of the soy protein concentrate suitable for the present invention, which mainly depends on the preparation method of the soy protein concentrate itself. In some specific embodiments of the present invention, the soy protein concentrate of the present invention comprises 30% to 80% by mass of protein (on a dry weight basis), preferably 65% ​​to 75% by mass of protein, and other small amounts of fat, ash, cellulose, lignin, oligosaccharide components, etc.

[0068] In addition, the above-mentioned soy protein concentrate may also include any desired pre-treatment process before the process of the present invention. There are no limitations on these pre-treatment processes in principle, and for example, the pre-treatment process may be crushed or ground to a desired particle size range, or residual ethanol may be removed under reduced pressure.

[0069] In a specific embodiment of the present invention, the soy protein concentrate of the present invention is substantially a soy protein concentrate obtained by the alcohol process. In other specific embodiments, the soy protein concentrate of the present invention can be a mixed protein concentrate of a protein concentrate obtained by the alcohol process and a protein concentrate obtained by another method, and preferably, the content of the protein concentrate obtained by the alcohol process in the mixed protein concentrate is 50% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0070] (Dispersed System)

[0071] In the present invention, the concentrated soy protein is dispersed in water to form a dispersion system. In addition, in order to improve the functionality of the final protein product, the dispersion system of the present invention includes the use of a nonionic surfactant.

[0072] Water can generally be used as a solvent for the dispersion system. In some specific embodiments, the soy protein concentrate content in the dispersion system, based on the dry weight of the soy protein concentrate, is 20% by mass or less, preferably 18% by mass or less, and more preferably 15% by mass or less, of the total mass of the dispersion system. Furthermore, there is no particular lower limit for the soy protein concentrate content, but it can generally be 1% by mass or more, preferably 3% by mass or more, and more preferably 5% by mass or more.

[0073] In the dispersion system of the present invention, if the content of soybean protein concentrate is too high, there may be concerns about poor dispersion of the soybean protein concentrate under certain industrial conditions; on the other hand, if the content of soybean protein concentrate is too low, there may be concerns about unnecessary reduction in production efficiency.

[0074] The nonionic surfactant of the present invention is not particularly limited as long as its HLB value satisfies 7 to 14. Preferably, the HLB value of the nonionic surfactant is 8 to 13, more preferably, the HLB value of the nonionic surfactant is 9 to 12, and most preferably, the HLB value of the ionic surfactant is 10 to 11. Therefore, a suitable hydrophilicity of the nonionic surfactant is advantageous for the present invention.

[0075] There is no particular restriction on the type of nonionic surfactant that meets the above conditions. In some specific embodiments, the nonionic surfactant of the present invention includes one or more of polyoxyalkylene ether surfactants of fatty alcohols, polyoxyalkylene fatty acid ester surfactants, polyoxyalkylene acrylic acid ester surfactants, and polyoxyalkylene ether sorbitan (fatty acid ester) surfactants. The fatty acid or fatty alcohol is preferably a long-chain (carbon number of 14 to 26) fatty acid or fatty alcohol, and preferably, the alkylene group is selected from an alkylene group with 1 to 4 carbon atoms, more preferably, the alkylene group is selected from an alkylene group with 2 or 3 carbon atoms, and further preferably, the alkylene group is an ethylene group.

[0076] Further, the types of specific nonionic surfactants that can be used in the present invention include:

[0077] Polyoxyethylene dioleate (HLB=7.5), tetraethylene glycol monostearate (HLB=7.7), tetraethylene glycol monooleate (HLB=7.7), polyoxypropylene mannitol dioleate (HLB=8.0), polyoxyethylene sorbitol lanolin oleic acid derivative (HLB=8.0), polyoxyethylene sorbitol lanolin derivative (HLB=8.0), polyoxypropylene stearate (HLB=8.0), polyoxyethylene (5EO) lanolin ether (HLB=8.0), sorbitan laurate (HLB=8.6), sorbitan laurate (HLB=8.6), polyoxyethylene fatty acid (HLB=8.6), polyoxyethylene oxypropylene oleate (HLB=9.0), polyoxyethylene sorbitol beeswax Wax derivatives (HLB = 9.0), tetraethylene glycol monolaurate (HLB = 9.4), polyoxyethylene lauryl ether (HLB = 9.5), polyoxyethylene (4EO) sorbitan monostearate (HLB = 9.6), hexaethylene glycol monostearate (HLB = 9.6), polyoxypropylene (5PO) lanolin ether (HLB = 10.0), polyoxyethylene (5EO) sorbitan monooleate (HLB = 10.0), polyoxyethylene esters of mixed fatty acids and resin acids (HLB = 10.2), polyoxyethylene cetyl ether (HLB = 10.3), polyoxyethylene (20EO) sorbitan tristearate (HLB = 10.5), polyoxyethylene lauryl ether (HLB = 10.8), polyoxyethylene Polyoxyethylene (20EO) sorbitan trioleate (HLB=11.0), polyoxyethylene oxypropylene oleate (HLB=11.0), polyoxyethylene lanolin derivative (HLB=11.0), polyoxyethylene monooleate (HLB=11.1), polyoxyethylene monostearate (HLB=11.1), polyoxyethylene monooleate (HLB=11.4), polyoxyethylene monooleate (HLB=11.4), polyoxyethylene monopalmitate (HLB=11.6), polyoxyethylene monostearate (HLB=11.6), polyoxyethylene (10EO) oleyl ether (HLB=12.0), polyoxyethylene monolaurate (HLB=12.8), polyoxyethylene alkylphenol (HLB=12.8 ... Oxyethylene (10EO) acetylated lanolin derivative (HLB=13.0), polyoxyethylene sorbitol lanolin derivative (HLB=13.0), polyoxyethylene alkyl aryl ether (HLB=13.0), polyoxyethylene monolaurate (HLB=13.1), polyoxyethylene lauryl ether (HLB=13.1), polyoxyethylene castor oil (HLB=13.3), polyoxyethylene vegetable oil (HLB=13.3), polyoxyethylene (4EO) sorbitan monolaurate (HLB=13.3), polyoxyethylene esters of mixed fatty acids and resin acids (HLB=13.5), polyoxyethylene sorbitol lanolin derivative (HLB=14.0), polyoxyethylene (24EO) cholesterol ether (HLB=14.0), polyoxypropylene (20PO) lanolin ether (HLB = 14.0).

[0078] Furthermore, the above-mentioned nonionic surfactants may be used alone or as a mixture of several.

[0079] In some more preferred embodiments of the present invention, the surfactants that can be used include: Tween 65, Tween 85, Tween 61, Tween 81, polyoxyethylene lauryl ether, polyoxyethylene oxypropylene oleate, polyoxyethylene sorbitol beeswax derivatives, tetraethylene glycol monolaurate, etc., or a mixture of one or more of the following.

[0080] Furthermore, regarding the amount of the nonionic surfactant used, in the present invention, based on the dry weight of the soy protein concentrate, the amount of the nonionic surfactant used can be 0.15-2.5% by mass, preferably 0.2-2.5% by mass, and more preferably 0.5-2.0% by mass. If the amount of the nonionic surfactant is too low or too high, the soy protein concentrate may not be sufficiently protected from subsequent high-temperature treatment, resulting in insufficient storage stability of the final soy protein product.

[0081] In addition, in some specific embodiments of the present invention, the pH value of the dispersed system can be in the (weakly) acidic range of 3.0 to 6.5. More advantageously, the pH value of the dispersed system is controlled within the range of 3.5 to 6. There is no particular limitation on the additives that can be used to adjust the pH value of the system. Conventional acidic reagents or buffer solutions in the art can be used. Typically, hydrochloric acid, citric acid, malic acid, or phosphoric acid buffer solutions can be used to adjust the pH value.

[0082] The necessary ingredients described above are mixed in water at room temperature to prepare a dispersion system. If necessary, appropriate heating, stirring, ultrasonic dispersion, etc. may be used. The heating temperature may not exceed 40°C, preferably below 35°C. Stirring may be performed by magnetic stirring or mechanical stirring.

[0083] (Heat treatment)

[0084] After obtaining the above-mentioned dispersion system, the present invention further heat-treats the dispersion system. The temperature of the heat treatment is not particularly limited in principle and may be no more than 150°C, preferably 110-140°C. If the temperature is too low, the recovery effect of alcohol denaturation of the protein concentrate will be poor, while if the temperature is too high, irreversible heat denaturation of the protein may occur.

[0085] To reduce the impact of high temperatures during heat treatment on protein components, the heat treatment described herein advantageously has a relatively fast processing speed, preferably no longer than 90 seconds, preferably 15 to 60 seconds. Therefore, in some specific embodiments, the heating rate during heat treatment is typically no less than 30°C / s, preferably above 40°C / s.

[0086] In some preferred embodiments of the present invention, the heat treatment can be performed using an instantaneous high-temperature treatment method. A typical example is flash evaporation. This method involves direct contact of the dispersion with saturated steam, causing the dispersion to rapidly reach the heat treatment temperature and maintain the temperature there for, for example, no longer than 90 seconds. The temperature is then rapidly cooled to below 70°C, preferably to 45-65°C, by passing through a flash evaporator.

[0087] (Post-processing)

[0088] In the present invention, after the above-mentioned treatment, optional post-treatment can be carried out as needed. These post-treatment steps include at least one of cooling, pH adjustment, centrifugation, homogenization, and sterilization.

[0089] In some preferred embodiments of the present invention, the system obtained by heat treatment (flash treatment) can be cooled to room temperature, centrifuged or not, and then the pH value can be adjusted to a neutral pH (e.g., about 6.5 to 7.5), followed by homogenization and sterilization. Furthermore, the final protein product can be obtained by drying or other treatments.

[0090] There are no particular restrictions on the drying conditions, and either freeze drying or spray drying can be used. Preferably, spray drying can be used. The solid content of the feed can be adjusted to a suitable range before spray drying. The inlet air temperature of the spray drying can be 160-200°C, and the outlet air temperature can be 80-90°C.

[0091] <Second Aspect>

[0092] In a second aspect of the present invention, a method for preparing soy protein is provided, which comprises the method for treating soy protein concentrate described in the first aspect, and further enzymatically hydrolyzing the protein product obtained by the above treatment method.

[0093] Enzymes that can be used for the enzymatic treatment may include various carbohydrases and optionally proteases.

[0094] In principle, there is no particular limitation on the carbohydrases applicable to the present invention, and the carbohydrases may include one or a combination of carbohydrases such as cellulase, hemicellulase, ligninase, xylanase, glucanase, arabinosidase, galactosidase, etc.; the protease applicable to the present invention may be selected from papain, alkaline protease, trypsin, pepsin, acid protease, neutral protease, proline endonuclease, or any combination thereof.

[0095] Regarding the conditions for enzymatic hydrolysis, in some specific embodiments of the present invention, the temperature can be 40-65°C, preferably in the range of 45-60°C, and the reaction time can be 0.5-2h; the amount of enzyme used can be 0.2-1% by mass based on the dry weight of the protein product obtained by the aforementioned treatment method in the system.

[0096] In the second aspect of the present invention, the protein content in the final protein product can be further increased by the above-mentioned enzymolysis treatment. In some preferred embodiments of the present invention, the protein content of the final protein product can be increased to more than 90% by mass by the enzymolysis reaction, which can reach the protein content level of current soy protein isolate.

[0097] <Third Aspect>

[0098] In the third aspect of the present invention, a method for preparing a soybean protein product and a method for preparing a product using the soybean protein product obtained in the first aspect or the second aspect of the present invention are provided.

[0099] The aforementioned soy protein products or products containing the aforementioned soy protein are not particularly limited and may include various foods and nutritional supplements. Furthermore, these soy protein products may be used alone as the primary ingredient to form a final edible product, or may be added as an additive to other edible ingredients to form a final edible product.

[0100] Foods may include various liquid, semi-solid or solid foods, which may be semi-finished or finished products. Specific examples of foods include various soy products, dairy products (e.g., liquid dairy products, powdered milk products, fermented dairy products), meat products, vegetarian meat products, flour products, beverages, baked goods (e.g., bread, cakes, biscuits), etc. Furthermore, the foods of the present invention also include various nutritional supplements, including functional nutritional meal replacements, health foods, and sports energy supplements.

[0101] The nutritional additives may be nutritional additives in feed, such as additives in feed used for raising cattle, sheep or pigs.

[0102] Example

[0103] The technical solution of the present invention will be further described below through specific embodiments. In the embodiments, "parts" represent weight basis.

[0104] (Detection Method)

[0105] 1. Solubility (NSI):

[0106] Accurately weigh 0.4 g of protein sample and disperse it in 40 mL of deionized water (0.1 M phosphate buffer, pH 7.1). After shaking at room temperature for 1 hour, centrifuge at 4500 rpm for 10 minutes. Collect 10 mL of the supernatant and determine the protein content using the Kjeldahl method. The solubility index (NSI) is the percentage of protein in the supernatant to the total protein content in the sample.

[0107] 2. Foaming property (FC):

[0108] Prepare a 5% aqueous solution of the protein, take 50 mL and pour it into a 150 mL graduated cylinder, shear it at 15000 rpm for 2 minutes with a shearing machine, and quickly record the volume of the foam (V0) after shearing.

[0109]

[0110] 3. Storage stability:

[0111] The storage stability of the present invention includes solubility storage stability and foaming storage stability. The soy protein product is placed in a sealed ziplock bag and stored in a constant temperature and humidity chamber at 37°C and 75% humidity. After 30 days, the solubility and foaming properties of the product are tested. Storage stability refers to the retention of solubility and foaming properties of the protein product after 30 days.

[0112] (raw material)

[0113] In the following embodiments of the present invention, the raw material used is preferably Wilcon F, an alcohol-based concentrated protein produced by Yihai Kerry.

[0114] (Examples 1 to 4 and Comparative Examples 1 to 8)

[0115] Example 1 :

[0116] Take 10 parts of alcohol-based concentrated protein and add them to 90 parts of water, add Tween 65 with 1% protein content, mix well, adjust the pH to 4.5 with 1 mol / L HCl, sterilize at 130°C for 30s, cool to 55°C after the reaction, adjust the pH to 7.0 with 1 mol / L NaOH, sterilize, and spray dry to obtain a soy protein product.

[0117] Example 2 :

[0118] Take 5 parts of alcohol-based concentrated protein and add them to 95 parts of water, add Tween 85 with 0.2% protein content, mix well, adjust the pH to 3.0 with 1 mol / L HCl, sterilize at 110°C for 15s, cool to 45°C after the reaction, adjust the pH to 6.5 with 1 mol / L NaOH, sterilize, and spray dry to obtain a soy protein product.

[0119] Example 3 :

[0120] Take 15 parts of alcohol-based concentrated protein and add them to 85 parts of water, add polyoxyethylene lauryl ether with a protein content of 2%, mix well, adjust the pH to 6.0 with 1 mol / L HCl, sterilize at 150°C for 60s, cool to 65°C after the reaction, adjust the pH to 7.5 with 1 mol / L NaOH, sterilize, and spray dry to obtain a soy protein product.

[0121] Example 4 :

[0122] Take 10 parts of alcohol-processed concentrated protein and add them to 90 parts of water, add Tween 65 with a protein content of 1%, mix well, adjust the pH to 4.5 with 1 mol / L HCl, sterilize at 130°C for 30 seconds, cool to 55°C after the reaction, add hemicellulase equivalent to 0.5% protein content, react for 1 hour, adjust the pH value of the enzymatic hydrolyzate to 4.5, centrifuge at 4000g for 10 minutes, collect the precipitate, add a certain amount of water to make the final solid content 10%, adjust the pH to 7.0 with 1 mol / L NaOH, sterilize, and spray dry to obtain a soy protein product.

[0123] Comparative Example 1 :

[0124] Different from Example 1, no emulsifier was added, and other conditions were kept unchanged to prepare a soybean protein product.

[0125] Comparative Example 2 :

[0126] The difference from Example 1 is that Tween 65 with a protein content of 0.1% is added, and other conditions are kept unchanged to prepare a soybean protein product.

[0127] Comparative Example 3 :

[0128] The difference from Example 1 is that Tween 65 with a protein content of 3% is added, and other conditions are kept unchanged to prepare a soybean protein product.

[0129] Comparative Example 4 :

[0130] The difference from Example 1 is that after instantaneous high-temperature sterilization, Tween 65 with a protein content of 1% is added, and other conditions are kept unchanged to prepare a soybean protein product.

[0131] Comparative Example 5 :

[0132] The difference from Example 1 is that Span 40 with a protein content of 1% is added, and other conditions are kept unchanged to prepare a soybean protein product.

[0133] Comparative Example 6 :

[0134] The difference from Example 1 is that Tween 60 with a protein content of 1% is added, and other conditions are kept unchanged to prepare a soybean protein product.

[0135] Comparative Example 7 :

[0136] The difference from Example 1 is that before the instantaneous high-temperature treatment, the pH of the protein dispersion was adjusted to 2.0, and other conditions were kept unchanged to prepare a soybean protein product.

[0137] Comparative Example 8 :

[0138] The difference from Example 1 is that before the instantaneous high-temperature treatment, the pH of the protein dispersion was adjusted to 7.0, and other conditions were kept unchanged to prepare a soybean protein product.

[0139] The process of Examples 1-3 and Comparative Examples 1-8 is summarized in Table 1.

[0140] Table 1

[0141] sample emulsifiers Instantaneous high temperature treatment Example 1 1% Tween 65 (HLB=10.5) pH = 4.5, 130°C, 30s Example 2 0.2% Tween 85 (HLB=11.8) pH = 3.0, 110°C, 15s Example 3 2% polyoxyethylene lauryl ether (HLB = 9.2) pH = 6.0, 150 ° C, 45 s Example 4 1% Tween 65 (HLB=10.5) pH = 4.5, 130°C, 30s Comparative Example 1 × pH = 4.5, 130°C, 30s Comparative Example 2 0.1% Tween 65 (HLB=10.5) pH = 4.5, 130°C, 30s Comparative Example 3 3% Tween 65 (HLB = 10.5) pH = 4.5, 130°C, 30s Comparative Example 4 1% Tween 65 (HLB=10.5) pH = 4.5, 130°C, 30s Comparative Example 5 1% Span 40 (HLB=6.7) pH = 4.5, 130°C, 30s Comparative Example 6 1% Tween 60 (HLB = 14.9) pH = 4.5, 130°C, 30s Comparative Example 7 1% Tween 65 (HLB=10.5) pH = 2.0, 130°C, 30s Comparative Example 8 1% Tween 65 (HLB=10.5) pH = 7.0, 130°C, 30s

[0142] (Result Evaluation)

[0143] The soybean protein products obtained in Examples 1-4 and Comparative Examples 1-8 were evaluated, and the results are shown in Table 2.

[0144] Table 2

[0145]

[0146] In Examples 1 to 4, the soy protein products have good storage stability, i.e., both dissolution storage stability and foaming storage stability are above 90%. In particular, the dissolution storage stability and foaming storage stability of Example 1 can reach above 95%. In Example 4, after hemicellulase hydrolysis, the protein content can reach above 90%, meeting the requirements of soy protein isolate. In comparison, the storage stability of Examples 1 to 8 is relatively poor, which seriously restricts the application of the protein.

[0147] It should be noted that, although the technical solutions of the present invention are described with specific examples, those skilled in the art will appreciate that the present disclosure should not be limited thereto.

[0148] While various embodiments of the present disclosure have been described above, the above descriptions are illustrative, non-exhaustive, and not intended to be limiting of the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is selected to best explain the principles of the embodiments, their practical applications, or improvements to existing technologies, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0149] Industrial applicability

[0150] The rice bran oil processing process provided by the present invention can be used industrially for processing or preparing various rice bran oils.

Claims

1. A method for processing soybean protein concentrate, characterized in that: The method comprises: The step of forming a dispersion system to form the soybean protein concentrate into a dispersion system, wherein the dispersion system includes a nonionic surfactant, The HLB value of the nonionic surfactant is 9 to 12, and the amount thereof is 0.15 to 2.5% by mass based on the dry weight of the soy protein concentrate, and the pH value of the dispersion system is 3.0 to 6.5; a heating treatment step for heating the dispersed system, wherein the heating temperature is above 110° C. and not more than 150° C., and the heating time is 15 to 60 seconds; The nonionic surfactant is one or more of Tween 65, Tween 85, polyoxyethylene lauryl ether, polyoxyethylene oxypropylene oleate, polyoxyethylene (4EO) sorbitan monostearate, polyoxyethylene (5EO) sorbitan monooleate, polyoxyethylene (20EO) sorbitan trioleate, polyoxyethylene monooleate, and polyoxyethylene monostearate.

2. The method according to claim 1, characterized in that The soybean protein concentrate includes soybean protein concentrate extracted by alcohol method.

3. The method according to claim 1 or 2, characterized in that In the step of forming a dispersed system, one or more of the following conditions are met: (1) The content of the soybean protein concentrate in the dispersed system is 1 to 20% by mass based on the dry weight of the soybean protein concentrate; (2) performing the step of forming the dispersed system at room temperature; (3) The pH value of the dispersed system is 4.0 to 6.

0.

4. The method according to claim 1 or 2, characterized in that In the step of heating treatment, the heating rate is not less than 30°C / s.

5. The method according to claim 1 or 2, characterized in that The heating step further includes at least one post-processing step of cooling, pH adjustment, centrifugation, homogenization, and sterilization.

6. A method for preparing soybean protein, characterized in that: The method comprises: a step of modifying the soybean protein concentrate, comprising treating the soybean protein concentrate with the method according to any one of claims 1 to 5 to obtain a modified soybean protein concentrate; The enzymatic hydrolysis step is to enzymatically hydrolyze the modified soybean protein concentrate to obtain the soybean protein.

7. The method according to claim 6, characterized in that The protein content of the soybean protein is 90% by mass or more.

8. A method for preparing a soybean protein product, characterized in that: The method comprises the method according to any one of claims 1 to 7.

9. A soybean protein product prepared by the method according to claim 8.

10. A food, characterized in that The soybean protein concentrate is prepared by the method according to any one of claims 1 to 5, or the soybean protein is prepared by the method according to claim 6 or 7, or the soybean protein product according to claim 9.

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