Bean flour and preparation method thereof

Abstract

The invention relates to bean flour and a preparation method thereof, and the method comprises the following steps: 1) enzymolysis: carrying out enzymolysis on a soybean milk base material by using tannase and phytase to obtain an enzymatic hydrolysate; 2) homogenizing: adding an emulsifier into the enzymatic hydrolysate for homogenizing to obtain a soybean milk solution; and 3) drying: drying the soybean milk solution obtained in the step 2) to obtain the soybean powder. The bean flour prepared by the method disclosed by the invention has high gel property, can be quickly brewed without adding excessive carbohydrates when being applied to the instant tofu pudding, and has relatively high coagulation hardness, and the prepared tofu pudding is uniform in texture and free of precipitation or floating conditions.

Description

Technical Field

[0001] The present invention relates to the field of food processing, and particularly to a method for preparing soybean powder. Background Art

[0002] Soybean curd is a traditional food in China with a long history. The traditional methods for making soybean curd are basically the same, that is, soaking soybeans, grinding the soybeans into slurry, filtering, boiling, and finally putting it into a larger container and adding a coagulant for coagulation. There are two major disadvantages of this traditional method for making soybean curd: one is that the production process is relatively cumbersome and the quantity is large, which is not suitable for ordinary families to make by themselves and they need to buy it in the store; the other is that the soybean curd must be made and sold immediately and is not suitable for long-term storage. Especially in summer, there is a high risk of deterioration. Therefore, this traditional method for making soybean curd has great limitations.

[0003] At present, many scholars are studying the preparation of soybean powder by spray-drying soybean milk and then redissolving the powder in water to make soybean curd. Compared with traditional soybean curd, the convenience and popularity have been greatly improved. For example, CN201611153142.7 controls the NSI of protein and the content of trypsin inhibitor by adjusting the temperature of boiling the soybean milk, and adds a certain amount of maltodextrin. The prepared soybean curd can achieve the texture and taste of traditional soybean curd; CN00112067.0 adds a certain amount of sodium erythorbate, sodium bicarbonate and dextrin to the slurry, and adjusts the pH value between 6.5 - 8.0 to obtain soybean powder with good dispersibility and solubility. However, in actual use, these products need to fully dissolve the soybean powder in hot water above 80°C for more than 10 minutes, and then add a coagulant and let it stand for 20 minutes to make high-hardness soybean curd. This way of making soybean curd is still not convenient enough in today's fast-paced life.

[0004] Other scholars are committed to researching more convenient-to-prepare soybean powder, that is, putting the soybean powder into hot water and completing the preparation of the soybean powder within 1 minute, adding a coagulant and letting it stand for 20 minutes to make soybean curd. For example, CN 200410014557.7 can achieve rapid preparation of soybean powder by adding reducing agents, emulsifiers and protease hydrolysis. The prepared soybean curd has a uniform texture, but the reducing agent and protease hydrolysis will greatly reduce the gel property of the soybean curd and affect the taste of the product; CN201711448511.X realizes rapid preparation of soybean powder by adding a large amount of sugar. The soybean curd has a uniform texture and a relatively high gel property, but the sweetness of the soybean curd is obvious, which severely restricts its application in salty soybean curd. Therefore, it is still necessary to develop a soybean powder raw material that can be conveniently prepared and has a wide range of applications. Summary of the Invention

[0005] Through long-term research, the inventors of the present invention have discovered a preparation method for improving the gel property of soybean powder; when the soybean powder prepared by the method of the present invention is applied to instant soy bean curd, rapid dissolution can be achieved without excessive addition of carbohydrates, and the effect of high gel property can be obtained.

[0006] In a first aspect, the present invention provides a preparation method of soybean powder, and the method comprises the following steps:

[0007] 1) Enzymatic hydrolysis: using tannase and phytase to carry out enzymatic hydrolysis on a soymilk base material to obtain an enzymatic hydrolysate;

[0008] 2) Homogenization: adding an emulsifier to the enzymatic hydrolysate for homogenization to obtain a soymilk solution;

[0009] 3) Drying: drying the soymilk solution obtained in step 2) to obtain soybean powder.

[0010] In one or more embodiments, the solid content in the soymilk base material is 5-30%, preferably 8-20%.

[0011] In one or more embodiments, based on the total mass of the solids in the soymilk base material, the dosage of the tannase is 0.3-5%, preferably 0.5-3%; the dosage of the phytase is 0.1-5%, preferably 0.5-2%.

[0012] In one or more embodiments, the temperature of the enzymatic hydrolysis is 30-70°C, preferably 40-60°C.

[0013] In one or more embodiments, the enzymatic hydrolysis time is 10-120 min, preferably 30-90 min.

[0014] In one or more embodiments, the HLB value of the emulsifier is 10-20, preferably 12-18.

[0015] Preferably, the emulsifier is a non-ionic emulsifier.

[0016] In one or more embodiments, based on the total mass of the solids in the soymilk base material, the dosage of the emulsifier is 0.1-5%, preferably 0.5-3%.

[0017] In one or more embodiments, the homogenization is high-pressure homogenization; preferably, the pressure of the homogenization is above 200 bar, for example, 200-1000 bar, preferably 300-800 bar.

[0018] In one or more embodiments, the soymilk solution further comprises a sterilization step before drying; preferably, the sterilization temperature is 80-100°C and the time is 5-30 min.

[0019] In one or more embodiments, the emulsifier is selected from one or more of Tween emulsifiers, polyoxyethylene alkylphenols, polyoxyethylene acetylated lanolin derivatives, polyoxyethylene sorbitol lanolin derivatives, polyoxyethylene alkyl aryl ethers, polyoxyethylene laurates, polyoxyethylene lauryl ethers, and polyoxyethylene vegetable oils.

[0020] Preferably, the emulsifier is selected from one or more of Tween 20, Tween 40, polyoxyethylene alkylphenols, polyoxyethylene monostearate, and polyoxyethylene laurates.

[0021] In a second aspect, the present invention also provides a soybean powder, which is obtained by the method described in any one of the present invention.

[0022] In one or more embodiments, the tannin content in the soybean powder is 1‰ or less, preferably 0.5‰ or less, for example, 0 - 0.5‰; and / or, the phytic acid content in the soybean powder is 2‰ or less, preferably 1‰ or less, for example, 0 - 1‰.

[0023] In a third aspect, the present invention also provides a method for preparing soy curd, the method comprising the step of preparing soybean powder by the method described in any one of the present invention, and the step of coagulating the soybean powder into soy curd.

[0024] In a fourth aspect, the present invention also provides a food or beverage comprising the soybean powder described in the present invention.

[0025] Preferably, the food is soy curd, tofu, or bean pudding.

[0026] Preferably, the beverage is soy milk, soy milk beverage, or bean yogurt.

[0027] In a fifth aspect, the present invention also provides the application of tannase and phytase in synergistically improving the gel property of soybean powder, by adding tannase and phytase to a soy milk base material for enzymatic hydrolysis to improve the gel property of soybean powder.

[0028] In one or more embodiments, based on the total mass of solids in the soy milk base material, the dosage of tannase is 0.3 - 5%, preferably 0.5 - 3%; the dosage of phytase is 0.1 - 5%, preferably 0.5 - 2%.

[0029] In one or more embodiments, after enzymatic hydrolysis of the soy milk base material, an emulsifier is added for homogenization; preferably, the HLB value of the emulsifier is 10 - 20, preferably 12 - 18.

[0030] Preferably, the emulsifier is a non - ionic emulsifier.

[0031] In one or more embodiments, the emulsifier is selected from one or more of Tween emulsifiers, polyoxyethylene alkylphenols, polyoxyethylene acetylated lanolin derivatives, polyoxyethylene sorbitol lanolin derivatives, polyoxyethylene alkyl aryl ethers, polyoxyethylene laurates, polyoxyethylene lauryl ethers, and polyoxyethylene vegetable oils.

[0032] Preferably, the emulsifier is selected from one or more of Tween 20, Tween 40, polyoxyethylene alkylphenols, polyoxyethylene monostearates, and polyoxyethylene laurates.

[0033] In one or more embodiments, based on the total mass of solids in the soy milk base material, the dosage of the emulsifier is 0.1 - 5%, preferably 0.5 - 3%. Detailed implementation manners

[0034] It should be understood that within the scope of the present invention, the above-mentioned various technical features of the present invention and the various technical features specifically described below (such as in the examples) can be combined with each other to form preferred technical solutions.

[0035] It should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. For the experimental methods without specific conditions indicated in the following examples, they are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer. Unless otherwise stated, all parts are parts by weight and all percentages are weight percentages.

[0036] Unless otherwise defined or stated, all professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to the described content can be applied to the method of the present invention.

[0037] Through repeated and in-depth research, the inventors of the present invention found that during the preparation process of soybean powder, by enzymatically hydrolyzing with tannase and phytase, reasonably controlling the contents of tannin and phytic acid, and then cooperating with an emulsifier with a specific HLB value, the gel performance of soybean powder can be effectively improved, thus completing the present invention.

[0038] The object of the present invention is to provide a method for preparing a soybean powder with high gel properties, and the method includes the following steps:

[0039] 1) Enzymatic hydrolysis: Using tannase and phytase to enzymatically hydrolyze the soy milk base material to obtain an enzymatically hydrolyzed solution;

[0040] 2) Homogenization: Adding an emulsifier to the enzymatically hydrolyzed solution for homogenization to obtain a soy milk solution;

[0041] 3) Drying: Drying the soy milk solution obtained in step 2) to obtain soybean powder.

[0042] In the present invention, the tannase refers to an enzyme that can hydrolyze the ester bond and phloroglucinol bond in tannins, and it can be commercially purchased or obtained by fermentation of Aspergillus niger or yeast.

[0043] In the present invention, the phytase refers to an enzyme that can catalyze the hydrolysis of phytic acid, and it can be commercially purchased or obtained by fermentation of Aspergillus niger or yeast.

[0044] The above enzyme preparations used in the present invention are well-known to those skilled in the art. Among them, the tannase can include, but is not limited to: Xiasheng FDY-2254, Caiwei Biology TAN-22, Jinke Biology JK-045; the phytase can include, but is not limited to: Xiasheng FDY-2244, FDG-2245, Hongrui Biology 37288-11-2, Jinke Biology JK-039. The specific usage conditions of the above enzymes are well-known to those skilled in the art. For example, the addition amount of the tannase can be 0.3-5% of the solid matter mass in the soybean milk base material, preferably 0.5-3%. For example, the addition amount of the phytase is 0.1-5% of the solid matter mass in the soybean milk base material, preferably 0.5-2%. The temperature of the enzymatic hydrolysis reaction can be comprehensively determined according to conditions such as the optimum temperature of the enzyme used, and the specific method is well-known to those skilled in the art, such as 30-70°C, preferably 40-60°C. The time of the enzymatic hydrolysis reaction is determined according to the contents of tannins and phytic acid after enzymatic hydrolysis, and the contents of tannins and phytic acid in the soybean milk base material are reduced as much as possible. For example, the enzymatic hydrolysis time is 10-120 min, preferably 30-90 min.

[0045] In the present invention, in the enzymatic hydrolysis step, the tannase and the phytase can be added simultaneously for enzymatic hydrolysis, or one enzyme can be added first for enzymatic hydrolysis and then the other enzyme can be added for enzymatic hydrolysis. For example, the tannase is added first, and enzymatic hydrolysis is carried out at 40-60°C for 30-90 min, and then the phytase is added, and enzymatic hydrolysis is carried out at 40-60°C for 30-90 min. Preferably, the tannase and the phytase are added simultaneously for enzymatic hydrolysis, which can save the enzymatic hydrolysis time.

[0046] In the present invention, the soybean milk base material refers to an aqueous protein solution obtained by grinding, boiling, and removing residues from beans. The preparation method of the soybean milk base material is conventional. For example, it can be prepared by the following method: Soaked overnight bean raw materials (including but not limited to soybeans, black beans, mung beans, red beans) are mixed with water, ground, boiled (for example, boiled at 90-100°C for 5-30 minutes), filtered to remove pulp residues, and the collected liquid part is the soybean milk base material. The specific grinding method is a conventional method in the art. For example: the methods mentioned by He Yufei (Research on the production process of soy milk, Shanxi Food Industry, 2002), Chen Cong et al. (Research on the boiling and separation links of the cooked soy milk process, Science and Technology of Food Industry, 2012).

[0047] In the present invention, the solid content in the soymilk base material refers to the percentage of the weight of the non-aqueous substances in the material to the total weight. The solid content in the soymilk base material is related to the material-liquid ratio. When the material-liquid ratio is 1:(2 - 10), the solid content should be in the range of 8 - 20%. For example, the preparation method of the soymilk base material with a solid content of 8% is as follows: Take the soybeans soaked overnight and mix them with water. Among them, the mass ratio of the soybeans before soaking to water is 1:8. Use a grinder to grind the soybeans to obtain raw paste slurry. Boil the raw paste slurry to obtain cooked paste slurry. Further separate the slurry from the residue for the cooked paste slurry. The collected liquid part is the soymilk base material with a solid content of 8%. Preferably, the pH value of the soymilk base material is between 6.0 and 7.0.

[0048] In the present invention, the emulsifier used is a non-ionic emulsifier. The HLB value of the emulsifier is 10 - 20, preferably 12 - 18. The emulsifier can be selected from one or more of Tween emulsifiers (such as Tween 20, Tween 40, Tween 60, Tween 80), polyoxyethylene alkylphenols, polyoxyethylene acetylated lanolin derivatives, polyoxyethylene sorbitan lanolin derivatives, polyoxyethylene alkyl aryl ethers, polyoxyethylene laurate, polyoxyethylene lauryl ether, and polyoxyethylene vegetable oils. Specifically, the emulsifier can be selected from one or more of Tween 20, Tween 40, Tween 60, Tween 80, polyoxyethylene alkylphenols, polyoxyethylene acetylated lanolin derivatives, polyoxyethylene sorbitan lanolin derivatives, polyoxyethylene alkyl aryl ethers, polyoxyethylene laurate, polyoxyethylene lauryl ether, polyoxyethylene vegetable oils, Tween 21, polyoxyethylene sorbitan lanolin derivatives, polyoxyethylene cholesterol ether, polyoxypropylene lanolin alcohol ether, polyoxyethylene sorbitan monolaurate, polyoxyethylene oleyl ether, polyoxyethylene methyl glucoside sesquioleate, polyoxyethylene monostearate, polyoxyethylene monooleate, polyoxyethylene oleyl ether, polyoxyethylene stearyl alcohol, polyoxyethylene oleyl alcohol, polyethylene glycol monopalmitate, polyoxyethylene cetyl alcohol, and polyoxyethylene oxypropylene stearate.

[0049] In the present invention, the homogenization is high-pressure homogenization. The pressure of the homogenization is above 200 bar, preferably 300 - 800 bar.

[0050] In the present invention, the method for drying the obtained soymilk solution is a conventional method in the art. Specifically, it may include but is not limited to spray drying, freeze drying, vacuum drying, and microwave drying.

[0051] In certain embodiments, the soymilk solution further includes a sterilization step before drying. The sterilization method is conventional. For example, sterilize at a temperature of 80 - 100 °C for 5 - 30 min.

[0052] The object of the present invention is to provide a kind of soybean powder, and the soybean powder is obtained by using any method described in the present invention.

[0053] In some embodiments, the tannin content in the soybean powder is below 1‰, preferably below 0.5‰, such as 0.01 - 0.5‰.

[0054] In some embodiments, the phytic acid content in the soybean powder is below 2‰, preferably below 1‰, such as 0.01 - 1‰.

[0055] The present invention also provides a food or beverage containing the above soybean powder. For example, the food is bean curd jelly, tofu, bean pudding, etc.; the beverage is soy milk, soy milk drink, soy yogurt, etc. Preferably, the food is bean curd jelly.

[0056] The present invention also provides a preparation method of bean curd jelly. The preparation method includes the step of preparing soybean powder by using any method described in the present invention, and the step of coagulating the soybean powder into bean curd jelly. For example, the bean curd jelly can be prepared by the following method: mixing the soybean powder described in the present invention with water at a temperature above 95°C according to a mass ratio of 1:(8 - 12), rapidly stirring for 1 - 5 min, adding 1 - 5% of a coagulant (such as glucono - δ - lactone, gypsum, bittern) based on the mass of the soybean powder, and standing for 20 - 40 min, then the bean curd jelly can be obtained.

[0057] The present invention has the following advantages:

[0058] 1. The soybean powder of the present invention is convenient to apply. The bean curd jelly prepared by using a rapid brewing method not only has a uniform texture, no precipitation or floating, but also has high gel property;

[0059] 2. The soybean powder of the present invention can be rapidly dissolved when being brewed. When applied to the preparation of bean curd jelly, there is no need to add too much carbohydrate to promote the dissolution of the soybean powder, and the bean curd jelly has no sweet taste, thus expanding its application scope.

[0060] The present invention will be described below in the form of specific embodiments. It should be understood that these embodiments are only illustrative and not used to limit the protection scope of the present invention. The materials and other methods used in the embodiments are conventional materials and methods in the art unless otherwise specified.

[0061] The following raw materials are used in the embodiments:

[0062] Tween 20, Tween 40, polyoxyethylene alkylphenol, polyoxyethylene monostearate, polyoxyethylene laurate, Span 60, all from Aladdin Reagent.

[0063] Tannase: Xiasheng Biology FDY - 2254.

[0064] Phytase: Xiasheng Biotech FDY-2244.

[0065] The following detection methods were used in the examples:

[0066] 1. Quick reconstitution method of soybean powder (i.e., preparation method of soy curd)

[0067] Accurately weigh 13 parts of soybean powder and place it in 130 parts of deionized water (above 95 °C). Rapidly stir with a glass rod for 1 min, immediately add 0.3 part of glucono-δ-lactone, and let it stand for 20 min to form soy curd.

[0068] 2. Gelatinization determination of soy curd

[0069] Take a cup of soy curd, use the gel center as the probing point, and measure the gel hardness with a TA.XT plus texture analyzer. Use a P / 0.5R cylindrical probe, the probe movement speed is 0.50 mm / sec, the trigger force is 4.0 g, the probing depth is 10.0 mm, and the maximum force received by the probe during movement is the size of the gelatinization.

[0070] 3. Sensory evaluation of soy curd

[0071] Take a cup of soy curd and observe it with the naked eye. Among them, ○ represents "the texture of the soy curd is uniform, without precipitation or floating"; Δ represents "the texture of the soy curd is relatively uniform, with slight floating and stratification"; × represents "the texture of the soy curd is rough, with obvious precipitation and floating and stratification".

[0072] 4. Detection of tannin content

[0073] Accurately weigh 1 g of the sample and place it in a 150 mL conical flask. Add 50 mL of deionized water and vibrate for extraction for 15 min. Add 5 mL of Zn(Ac)2 standard solution (1.000 mol / L) and 3.5 mL of concentrated ammonia water to a 100 mL volumetric flask, shake well, and slowly transfer the extract into the volumetric flask, shaking continuously. Keep it warm in a 35 °C water bath for 20 - 30 min, cool it, make up the volume to 100 ml with water, mix well, let it stand, filter, and collect the filtrate. Accurately pipette 10 ml of the filtrate and place it in a 150 ml conical flask, add 40 ml of deionized water, 12.5 ml of NH3-NH4Cl buffer solution, and 10 drops of eriochrome black T indicator, and mix well. Titrate with 0.05 mol / L EDTA standard solution until the solution changes from wine red to blue as the end point. The calculation formula is as follows:

[0074]

[0075] X—the mass fraction of tannin in the sample, %

[0076] C1—the concentration of Zn(Ac)2 standard solution, mol / L

[0077] V1—Volume of the Zn(Ac)2 standard solution, mL

[0078] C2—Concentration of the EDTA standard solution, mol / L

[0079] V2—Volume of the EDTA standard solution consumed during titration, mL

[0080] m—Mass of the sample, g

[0081] 5. Detection of phytic acid content

[0082] Determination was carried out according to the method of GB 5009.153-2016.

[0083] Example 1

[0084] Preparation of soymilk base material: Take the soybeans soaked overnight and mix them with water. Among them, the mass ratio of soybeans to water before soaking is 1:5. Grind them with a grinder to obtain raw paste slurry. Boil the raw paste slurry to obtain cooked paste slurry. Further separate the pulp from the cooked paste slurry. The collected liquid part is the soymilk base material with a solid content of 12%;

[0085] Enzymatic hydrolysis: Based on the total mass of solids in the soymilk base material, add 1% tannase and 0.6% phytase to the soymilk base material with a solid content of 12%, and carry out enzymatic hydrolysis at 50 °C for 60 min to obtain an enzymatic hydrolysate;

[0086] Homogenization: Based on the total mass of solids in the soymilk base material, add 1% Tween 20 (HLB value is 16.7) to the enzymatic hydrolysate, and carry out homogenization at a pressure of 600 bar to obtain soymilk solution;

[0087] Sterilization and drying: The homogenized soymilk solution is sterilized at 95 °C for 15 min, and then spray-dried to prepare soy powder sample 1. After detection, the tannin content of soy powder sample 1 is 0.16‰, and the phytic acid content of the soy powder is 0.52‰.

[0088] Example 2

[0089] Preparation of soymilk base material: Take the soybeans soaked overnight and mix them with water. Among them, the mass ratio of soybeans to water before soaking is 1:8. Use a grinder to grind them to obtain raw paste slurry. Boil the raw paste slurry to obtain cooked paste slurry. Further separate the pulp from the cooked paste slurry. The collected liquid part is the soymilk base material with a solid content of 8%;

[0090] Enzymatic hydrolysis: Based on the total mass of solids in the soymilk base material, add 0.6% tannase and 0.3% phytase to the soymilk base material with a solid content of 8%, and carry out enzymatic hydrolysis at 40 °C for 30 min to obtain an enzymatic hydrolysate;

[0091] Homogenization: Based on the total mass of solids in the soymilk base material, 0.5% of polyoxyethylene alkylphenol (HLB value is 12.8) was added to the enzymatic hydrolysate, and homogenization was carried out at a pressure of 300 bar to obtain a soymilk solution;

[0092] Sterilization and drying: The homogenized soymilk solution was sterilized at 100 °C for 5 min, and then spray-dried to prepare soymilk powder sample 2. After detection, the tannin content of soymilk powder sample 2 was 0.36‰, and the phytic acid content of the soymilk powder was 0.86‰.

[0093] Example 3

[0094] Preparation of soymilk base material: Take the soybeans soaked overnight and mix them with water. Among them, the mass ratio of soybeans to water before soaking is 1:2.5. Use a grinder to grind the soybeans to obtain a raw paste slurry. Boil the raw paste slurry to obtain a cooked paste slurry. The cooked paste slurry is further separated into pulp and residue, and the collected liquid part is the soymilk base material with a solids content of 20%;

[0095] Enzymatic hydrolysis: Based on the total mass of solids in the soymilk base material, 0.5% of tannase and 0.4% of phytase were added to the soymilk base material with a solids content of 20%, and enzymatic hydrolysis was carried out at 60 °C for 90 min to obtain an enzymatic hydrolysate;

[0096] Homogenization: Based on the total mass of solids in the soymilk base material, 2% of polyoxyethylene monostearate (HLB value is 17.9) was added to the enzymatic hydrolysate, and homogenization was carried out at a pressure of 400 bar to obtain a soymilk solution;

[0097] Sterilization and drying: The homogenized soymilk solution was sterilized at 90 °C for 30 min, and then spray-dried to prepare soymilk powder sample 3. After detection, the tannin content of soymilk powder sample 3 was 0.41‰, and the phytic acid content of the soymilk powder was 0.78‰.

[0098] Example 4

[0099] Preparation of soymilk base material: Take the soybeans soaked overnight and mix them with water. Among them, the mass ratio of soybeans to water before soaking is 1:5. Use a grinder to grind the soybeans to obtain a raw paste slurry. Boil the raw paste slurry to obtain a cooked paste slurry. The cooked paste slurry is further separated into pulp and residue, and the collected liquid part is the soymilk base material with a solids content of 12%;

[0100] Enzymatic hydrolysis: Based on the total mass of solids in the soymilk base material, 1% of tannase was added to the soymilk base material with a solids content of 12%, and enzymatic hydrolysis was carried out at 50 °C for 60 min. Then 0.6% of phytase was added, and enzymatic hydrolysis was carried out at 50 °C for 60 min to obtain an enzymatic hydrolysate;

[0101] Homogenization: Based on the total mass of solids in the soybean milk base material, 1% of Tween 20 (HLB value of 16.7) was added to the enzymatic hydrolysate, and homogenization was carried out at a pressure of 600 bar to obtain a soybean milk solution;

[0102] Sterilization and drying: The homogenized soybean milk solution was sterilized at 95 °C for 15 min, and a soybean powder sample 4 was prepared by spray drying. After testing, the tannin content of the soybean powder sample 4 was 0.13‰, and the phytic acid content of the soybean powder was 0.54‰.

[0103] Example 5

[0104] Preparation of soybean milk base material: The soybeans soaked overnight were mixed with water. Among them, the mass ratio of soybeans to water before soaking was 1:5. The soybeans were ground using a grinder to obtain a raw paste slurry, the raw paste slurry was cooked to obtain a cooked paste slurry, and the cooked paste slurry was further separated into pulp and residue. The collected liquid part was the soybean milk base material with a solids content of 12%;

[0105] Enzymatic hydrolysis: Based on the total mass of solids in the soybean milk base material, 1% of tannase and 0.6% of phytase were added to the soybean milk base material with a solids content of 12%, and enzymatic hydrolysis was carried out at 50 °C for 60 min to obtain an enzymatic hydrolysate;

[0106] Homogenization: Based on the total mass of solids in the soybean milk base material, 0.5% of Tween 40 (HLB value of 12.6) and 0.5% of polyethylene glycol laurate (HLB value of 16.3) were added to the enzymatic hydrolysate, and homogenization was carried out at a pressure of 600 bar to obtain a soybean milk solution;

[0107] Sterilization and drying: The homogenized soybean milk solution was sterilized at 95 °C for 15 min, and a soybean powder sample 5 was prepared by spray drying. After testing, the tannin content of the soybean powder sample 5 was 0.15‰, and the phytic acid content of the soybean powder was 0.53‰.

[0108] Example 6

[0109] Preparation of soybean milk base material: The soybeans soaked overnight were mixed with water. Among them, the mass ratio of soybeans to water before soaking was 1:5. The soybeans were ground using a grinder to obtain a raw paste slurry, the raw paste slurry was cooked to obtain a cooked paste slurry, and the cooked paste slurry was further separated into pulp and residue. The collected liquid part was the soybean milk base material with a solids content of 12%;

[0110] Enzymatic hydrolysis: Based on the total mass of solids in the soybean milk base material, 1% of tannase and 0.6% of phytase were added to the soybean milk base material with a solids content of 12%, and enzymatic hydrolysis was carried out at 50 °C for 60 min to obtain an enzymatic hydrolysate;

[0111] Homogenization: Based on the total mass of solids in the soybean milk base material, 1% of Tween 20 (HLB value 16.7) was added to the enzymatic hydrolysate, and homogenization was carried out at a pressure of 600 bar to obtain a soybean milk solution;

[0112] Drying: The homogenized slurry was dried using a freeze dryer to prepare sample 6. After testing, the tannin content of the soybean powder sample 6 was 0.14‰, and the phytic acid content of the soybean powder was 0.50‰.

[0113] Example 7

[0114] Soybean powder was prepared according to the method of Example 1, where the addition amounts of tannase and phytase were different, 0.2% of tannase and 0.1% of phytase were added, and other conditions remained unchanged to prepare soybean powder sample 7. After testing, the tannin content of the soybean powder sample 7 was 2.11‰, and the phytic acid content of the soybean powder was 3.22‰.

[0115] Example 8

[0116] Soybean powder was prepared according to the method of Example 1, where the addition amount of the emulsifier was different, 0.1% of Tween 20 (HLB value 16.7) was added, and other conditions remained unchanged to prepare soybean powder sample 8. After testing, the tannin content of the soybean powder sample 8 was 0.18‰, and the phytic acid content of the soybean powder was 0.47‰.

[0117] Example 9

[0118] Soybean powder was prepared according to the method of Example 1, where the addition amount of the emulsifier was different, 4% of Tween 20 (HLB value 16.7) was added, and other conditions remained unchanged to prepare soybean powder sample 9. After testing, the tannin content of the soybean powder sample 9 was 0.17‰, and the phytic acid content of the soybean powder was 0.49‰.

[0119] Example 10

[0120] Soybean powder was prepared according to the method of Example 1, where the homogenization pressure was different, the high-pressure homogenization pressure was 200 bar, and other conditions remained unchanged to prepare soybean powder sample 10. After testing, the tannin content of the soybean powder sample 10 was 0.16‰, and the phytic acid content of the soybean powder was 0.51‰.

[0121] Comparative Example 1:

[0122] Soybean powder was prepared according to the method of Example 1, where enzymatic hydrolysis and high-pressure homogenization were not carried out, and no emulsifier was added, and other conditions remained unchanged to prepare soybean powder sample 11. After testing, the tannin content of the soybean powder sample 11 was 3.56‰, and the phytic acid content of the soybean powder was 6.44‰.

[0123] Comparative Example 2:

[0124] Prepare soy flour according to the method of Example 1. Among them, tannase is not added, and other conditions remain unchanged to obtain soy flour sample 12. After testing, the tannin content of soy flour sample 12 is 3.59‰, and the phytic acid content of the soy flour is 0.49‰.

[0125] Comparative Example 3:

[0126] Prepare soy flour according to the method of Example 1. Among them, phytase is not added, and other conditions remain unchanged to obtain soy flour sample 13. After testing, the tannin content of soy flour sample 13 is 0.18‰, and the phytic acid content of the soy flour is 6.28‰.

[0127] Comparative Example 4

[0128] Soy flour sample 14 is commercially available soy flour (Longwang soy flour). After testing, the tannin content of soy flour sample 14 is 3.82‰, and the phytic acid content of the soy flour is 6.31‰.

[0129] Comparative Example 5:

[0130] Prepare soy flour according to the method of Example 1. Among them, emulsifier is not added, and other conditions remain unchanged to obtain soy flour sample 15. After testing, the tannin content of soy flour sample 15 is 0.16‰, and the phytic acid content of the soy flour is 0.49‰.

[0131] Comparative Example 6:

[0132] Prepare soy flour according to the method of Example 1. Among them, the type of emulsifier added is different, and 1% of Span 60 (HLB value is 4.7) is added, and other conditions remain unchanged to obtain soy flour sample 16. After testing, the tannin content of soy flour sample 16 is 0.18‰, and the phytic acid content of the soy flour is 0.54‰.

[0133] For the soy flour samples obtained in the above examples and comparative examples, prepare douhua according to the rapid dissolution method of soy flour, and conduct gel property tests and sensory evaluations. The results are shown in Table 1.

[0134] Table 1 Gel property tests and sensory evaluations of douhua in examples and comparative examples

[0135]

[0136]

[0137] According to the results in the above table, it can be seen that the soybean powder prepared in Examples 1-10 can endow the soy flower with good gel properties, with the gel hardness ≥ 19.5. Preferably, the gel hardness of Examples 1-6 can reach above 30, and the texture of the soy flower is uniform without obvious precipitation or floating; when the soybean powder of Comparative Examples 1-6 is applied to the soy flower, the gel hardness of the soy flower is lower, the formability is poor, and there are situations of non-uniform texture, precipitation or floating.

[0138] The above are only the preferred embodiments of the present invention, and are not intended to limit the scope of the essential technical content of the present invention. The essential technical content of the present invention is broadly defined in the scope of the claims of the application. Any technical entity or method completed by others, if it is exactly the same as that defined in the scope of the claims of the application, or is an equivalent change, will be regarded as covered by the scope of the claims.

[0139] All the documents mentioned in the present invention are cited in this application as references, just as if each document is cited separately as a reference. In addition, it should be understood that after reading the above content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

Claims

1. A method for preparing soybean powder, characterized in that, The method comprises the following steps: 1) Enzymatic hydrolysis: The soymilk base material is subjected to enzymatic hydrolysis using tannase and phytase to obtain an enzymatic hydrolysate; 2) Homogenization: An emulsifier is added to the enzymatic hydrolysate for homogenization to obtain a soymilk solution; 3) Drying: The soymilk solution obtained in step 2) is dried to obtain soymilk powder.

2. The preparation method according to claim 1, characterized in that, The method has one or more of the following characteristics: A. The solid content in the soymilk base material is 5 - 30%, preferably 8 - 20%; B. Based on the total mass of the solids in the soymilk base material, the dosage of tannase is 0.3 - 5%, preferably 0.5 - 3%; the dosage of phytase is 0.1 - 5%, preferably 0.5 - 2%; C. The temperature of the enzymatic hydrolysis is 30 - 70°C, preferably 40 - 60°C; D. The time of the enzymatic hydrolysis is 10 - 120 min, preferably 30 - 90 min; E. The HLB value of the emulsifier is 10 - 20, preferably 12 - 18; F. The emulsifier is a non-ionic emulsifier; G. Based on the total mass of the solids in the soymilk base material, the dosage of the emulsifier is 0.1 - 5%, preferably 0.5 - 3%; H. The homogenization is high-pressure homogenization; preferably, the pressure of the homogenization is above 200 bar, preferably 300 - 800 bar.

3. The preparation method according to claim 1, characterized in that, Before drying, the soymilk solution further includes a sterilization step; preferably, the sterilization temperature is 80 - 100°C and the time is 5 - 30 min.

4. The preparation method according to claim 1, characterized in that, The emulsifier is selected from one or more of tween emulsifiers, polyoxyethylene alkylphenols, polyoxyethylene acetylated lanolin derivatives, polyoxyethylene sorbitol lanolin derivatives, polyoxyethylene alkyl aryl ethers, polyoxyethylene laurate, polyoxyethylene lauryl ether, and polyoxyethylene vegetable oils; preferably, the emulsifier is selected from one or more of tween 20, tween 40, polyoxyethylene alkylphenols, polyoxyethylene monostearate, and polyoxyethylene laurate.

5. A kind of soybean powder, characterized in that, The soymilk powder is prepared by the method described in any one of claims 1 - 4.

6. The soy flour according to claim 5, wherein The tannin content in the soymilk powder is 1‰ or less, preferably 0.5‰ or less; and / or, the phytic acid content in the soymilk powder is 2‰ or less, preferably 1‰ or less.

7. A method for preparing douhua, characterized in that, The method includes the step of preparing soymilk powder by the method described in any one of claims 1 - 4, and the step of coagulating the soymilk powder into soymilk curd.

8. A food or beverage, which contains the soymilk powder described in claim 5; preferably, the food is soymilk curd, tofu, or bean pudding; preferably, the beverage is soymilk, soymilk drink, or bean yogurt.

9. Application of tannase and phytase in synergistically improving the gel property of soybean powder, characterized in that, Tannase and phytase are added to the soymilk base material for enzymatic hydrolysis; preferably, based on the total mass of the solids in the soymilk base material, the dosage of tannase is 0.3 - 5%, preferably 0.5 - 3%; The dosage of phytase is 0.1 - 5%, preferably 0.5 - 2%.

10. The application according to claim 9, characterized in that, After the soymilk base material is enzymatically hydrolyzed, an emulsifier is added for homogenization; preferably, the HLB value of the emulsifier is 10 - 20.

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