A method for extracting soybean isoflavones, soybean saponins, soybean stachyose and raffinose without the participation of organic chemical solvents

Abstract

The present invention provides a method for extracting soybean isoflavones, soybean saponins, soybean stachyose and raffinose without the participation of organic chemical solvents. The method comprises: step 1, selecting low-temperature desolventized soybean meal as raw material; step 2, alkaline hot water leaching; step 3, sending a mixed aqueous solution composed of soybean isoflavones dissolved in 90°C alkaline hot water, soybean saponins, soybean stachyose and raffinose soluble at room temperature and heated precipitated solid phase soybean protein into a sifter for filtration, sending the liquid phase obtained by sieving to step 5, and sending the solid phase intercepted to step 4; step 4, drying; step 5, neutralization; step 6, desalting; step 7, resin adsorption; step 8, extracting soybean saponins; step 9, extracting soybean isoflavones; step 10, second water washing, separation, purification and drying; and completely eliminating the fear of chemical agents that are harmful to the human body caused by the use of organic chemical solvents such as ethanol, methanol, acetone and ethyl acetate in the extraction process.

Description

Technical Field

[0001] The invention relates to the technical field of bean food processing, and in particular to a method for extracting soybean isoflavones, soybean saponin, soybean stachyose and raffinose without the participation of chemical solvents. Background Art

[0002] Soybean is a major crop that can be used as both medicine and food. Modern studies have found that soybean isoflavones, soybean saponins, soybean stachyose, raffinose and other ingredients play an important role in human health and medical care, and long-term use has no toxic side effects. It is both food and medicine, so it is called "soybean health function factor". However, in the extraction process of "soybean health function factor", chemical solvents such as ethanol, methanol, acetone or ethyl acetate are required for extraction. Since chemical solvents such as ethanol are flammable and explosive, the workload of production safety prevention is increased, and the long-term harmful effects of residual solvents on the human body are difficult to predict. Summary of the invention

[0003] In view of the above problems, the purpose of the present invention is to provide a method for extracting soybean isoflavones, soybean saponins, soybean stachyose and raffinose without the participation of chemical solvents, adopting a method for extracting soybean isoflavones, soybean saponins, soybean stachyose and raffinose without the participation of organic chemical solvents to overcome the shortcomings of the above-mentioned prior art.

[0004] The present invention provides a method for extracting soybean isoflavones, soybean saponins, soybean stachyose and raffinose without the participation of organic chemical solvents, which is characterized by specifically comprising the following steps:

[0005] Step 1: Raw material selection

[0006] The low-temperature desolventized soybean meal (white bean flakes) after soybean oil immersion is selected as the raw material. Different from the general ethanol extraction or methanol extraction process, in order to prevent the formation of slurry during the heating water extraction in step 2, which affects the extraction of functional components, the soybean meal is not crushed in this step, but the whole white bean flakes are used as the raw material;

[0007] Step 2: Alkaline hot water leaching

[0008] The raw soybean meal (white bean flakes) of step 1 is sent to an extraction tank with a stirring heater, and pure water above 90°C is added to the extraction tank. According to the principle that soybean isoflavones are soluble in alkaline hot water, NaOH is added at the same time to adjust the pH value to 10-12. The amount of water added is about 10 times the weight of the soybean meal, the stirring speed is 30-60r / min, the stirring time is 4-6h, and the water temperature is maintained at 90°-100°C using a heater;

[0009] Step 3, the above production principle is based on the principle that all proteins in soybean meal can produce thermal denaturation precipitation in hot water. Soy isoflavones (including genistein and genistein) that are insoluble in water at room temperature can be converted from insoluble to soluble in alkaline hot water of >90°C due to their biological characteristics. The mixed aqueous solution composed of soy isoflavones soluble in hot water above 90°C, soy saponins and soy oligosaccharides (including stachyose and raffinose) that are originally soluble in water at room temperature and the heated precipitated solid phase soy protein are sent to a 60-mesh sifter for filtration. The delivery pump power is 10kw and the working pressure is 0.2Mpa~0.4Mpa. The liquid phase obtained by screening is sent to step 5, and the solid phase retentate is sent to step 4;

[0010] Step 4: Drying

[0011] The solid phase retentate obtained by filtration and separation in step 3 is dried in an automatic friction dryer with a power of 100kw and a rotation speed of 1450r / min, and the moisture content is ≤9%. The obtained product is "feed grade concentrated protein";

[0012] Step 5: Neutralization

[0013] The liquid phase obtained by the screening machine in step 3 is sent to an insulated neutralization tank with a heating stirrer, and food-grade hydrochloric acid is added to adjust the pH to 7.0;

[0014] Step 6: Desalination

[0015] The neutral mixed liquid with a temperature of about 90°C and a pH of 7.0 obtained in step 5 is pumped into an electrodialysis desalination device, the feed pump pressure is 0.15Mpa to 0.25Mpa, the electrodialysis device current is 18A to 20A, and the mixed conductivity after desalination should be between 100μs / cm and 300μs / cm;

[0016] Step 7: Resin adsorption

[0017] The liquid phase with a temperature of ≥90°C obtained after electrodialysis desalination in step 6 is pumped into a macroporous resin adsorption device (such as HP-20, D33), the components adsorbed by the resin are soybean isoflavones and soybean saponins, and the outflowing liquid phase is a water-soluble soybean oligosaccharide liquid such as soybean stachyose and raffinose;

[0018] Step 8: Extract soybean stachyose and raffinose

[0019] The soybean oligosaccharide mixture liquid flowing out after macroporous resin adsorption in step 7 is pumped into the nanofiltration (nF) "membrane separation device". The membrane pore size is selected to be able to retain sugars with a relative molecular mass of more than 500, and the working pressure is 1.5Mpa, that is, raffinose with a relative molecular mass of 594 and stachyose with a relative molecular mass of 738 are retained, while sucrose (relative molecular mass of 342) and glucose with a relative molecular mass of less than 500 flow out through the filter membrane. The effluent can be discharged as liquid discharge to a sewage treatment pool for unified treatment, which does not belong to the content included in this patent.

[0020] The purity of stachyose and raffinose intercepted by the nanofiltration membrane (nF) is ≥25%. Through vacuum concentration, the water content is ≤25%, and the product can be directly filled into "stachyose and raffinose mixed syrup".

[0021] Step 9: Extract soybean saponin

[0022] Taking advantage of the biological characteristics that soybean saponins can be dissolved in water at room temperature below 60°C, while soybean isoflavones (including genistein and genistein) can only be dissolved in hot water above 80°C, the soybean saponins adsorbed on the macroporous resin in step 7 are eluted with water at room temperature below 60°C, and the eluent is a soybean saponin solution. After the soybean saponin solution is concentrated, the solid concentration reaches about 10%, and after conventional sterilization, it is pumped into a spray drying tower, and the obtained solid powder with a moisture content of ≤7% is the soybean saponin;

[0023] Step 10: Extract soy isoflavones

[0024] The macroporous resin residue after eluting soybean saponin in step 9 is eluted 2 to 3 times with alkaline hot water with a temperature higher than 90°C and a pH of 10 to 12, so that all the macroporous resin adsorbents are dissolved and eluted, and then the eluate is neutralized to pH 7.0 by adding food-grade hydrochloric acid. After desalting by "electrodialysis", it is sent to a cooling tank. The cooling tank is surrounded by a running water bath to reduce the temperature to below 20°C, and soybean isoflavones (including genistein and genistein) are precipitated and precipitated as a solid phase. The precipitated solid and the mixed solution are sent together to a filter cloth with a pressure of 0.1Mpa to 0.3Mpa. In the target filter press, the solids obtained by filtration and interception at this time are crude soybean isoflavones;

[0025] Step 11: Second washing, separation, purification and drying

[0026] The crude soybean isoflavones obtained in step 10 are added with 20 to 30 times of purified water, and heated to above 90°C to dissolve the soybean isoflavones (including genistein and genistein). The solution at a temperature above 90°C is pumped into a filter cloth having a pressure of 0.2Mpa to 0.3Mpa. In the purpose filter press, the solid phase retained by the filter press is non-water-soluble, non-isoflavone impurities, which can be used as solid discharge and as feed or fertilizer; the permeate is concentrated to about 20% by a concentration device, and the concentrated liquid is then sent to a pressure spray drying tower with an inlet temperature of 170°C to 180°C and an outlet temperature of 70°C to 80°C. The powder with a moisture content of ≤7% obtained by spray drying is the product "soy isoflavones (including genistein and genistein)".

[0027] The advantages and positive effects of the present invention are:

[0028] 1. The present invention aims at the technical defect that the current preparation of soybean isoflavones, soybean saponins and soybean oligosaccharides requires extraction with organic solvents such as ethanol, methanol, acetone and ethyl acetate. According to the biological characteristics of soybean isoflavones, soybean saponins, soybean stachyose and raffinose, which require different temperature and pH conditions of solvent water when dissolved in water, a new extraction technology of soybean isoflavones, soybean saponins, soybean stachyose and raffinose without the participation of organic chemical solvents is adopted.

[0029] 2. The present invention completely eliminates the fear of organic chemical agents that are harmful to the human body caused by the use of organic chemical solvents such as ethanol, methanol, acetone, and ethyl acetate in the extraction process of soybean isoflavones, soybean saponins, soybean stachyose, and raffinose. Since there is no organic chemical solvent such as ethanol involved in the entire production process, the fire hazard of flammable and explosive production processes is eliminated, making industrial production safer.

[0030] 3. In the present invention, the soybean meal is not crushed, but the whole white bean slices are used as raw materials, which can prevent the formation of slurry during the heating water leaching in step 2, thereby affecting the extraction of functional components.

[0031] 4. The process of the present invention is a continuous extraction method of sequentially extracting soybean stachyose, raffinose - extracting soybean saponin - extracting soybean isoflavones, which makes the process short, the energy consumption low, and suitable for industrial production. DETAILED DESCRIPTION

[0032] In the following description, for the purpose of illustration, in order to provide a comprehensive understanding of one or more embodiments, many specific details are set forth. However, it is apparent that these embodiments may also be implemented without these specific details. In other examples, for ease of describing one or more embodiments, known structures and devices are shown in the form of block diagrams.

[0033] The present embodiment provides a method for extracting soybean isoflavones, soybean saponins, soybean stachyose, and raffinose without the participation of an organic chemical solvent, which specifically comprises the following steps:

[0034] Step 1: Raw material selection

[0035] The low-temperature desolventized soybean meal (white bean flakes) after soybean oil immersion is selected as the raw material. Different from the general ethanol extraction or methanol extraction process, in order to prevent the formation of slurry during the heating water extraction in step 2, which affects the extraction of functional components, the soybean meal is not crushed in this step, but the whole white bean flakes are used as the raw material;

[0036] Step 2: Hot water leaching

[0037] The raw soybean meal (white bean flakes) of step 1 is sent to an extraction tank with a stirring heater, and purified water above 90°C is added to the extraction tank. According to the biological characteristics of soybean isoflavones that are easily soluble in alkaline hot water, food-grade NaOH is added at the same time, and the pH value is adjusted to 10-12. The amount of water added is 5-10 times the weight of the soybean meal, the stirring speed is 30-60r / min, the stirring time is 4-6h, and the water temperature is maintained at 80°-100°C using a heater;

[0038] Step 3, the above production principle is based on the principle that all proteins in soybean meal can produce thermal denaturation precipitation in hot water above 80°C. Soy isoflavones (including genistein and genistein) that are insoluble in water at room temperature can be converted from insoluble to soluble in alkaline hot water above 90°C due to their biological characteristics. The mixed aqueous solution composed of soy isoflavones soluble in hot water above 90°C and soy saponins, soy stachyose and raffinose that are originally soluble in water at room temperature and the heated precipitated solid phase soy protein are sent to a 60-mesh sifter for filtration. The delivery pump power is 10kw and the working pressure is 0.2Mpa~0.4Mpa. The liquid phase obtained by screening is sent to step 5, and the solid phase is sent to step 4;

[0039] Step 4: Drying

[0040] The solid phase retentate obtained by filtration and separation in step 3 is dried in an automatic friction dryer with a power of 100kw and a rotation speed of 1450r / min, and the moisture content is ≤9%. This product is "feed grade concentrated protein".

[0041] Step 5: Neutralization

[0042] The liquid phase obtained by the screening machine in step 3 is sent to an insulated neutralization tank with a heating stirrer, and food-grade hydrochloric acid is added to adjust the pH to 7.0;

[0043] Step 6: Desalination

[0044] The neutral mixed liquid with a temperature of ≈90°C and a pH of 7.0 obtained in step 5 is pumped into the "electrodialysis desalination device", the feed pump pressure is 0.15Mpa-0.25Mpa, the electrodialysis device current is 18A-20A, and the mixed conductivity after desalination should be 100μs / cm-300μs / cm;

[0045] Step 7: Resin adsorption

[0046] The liquid phase obtained after electrodialysis desalination in step 6 with a temperature of ≈90°C is sent to a macroporous resin adsorption device (such as HP-20, D33), and the components adsorbed by the resin are soybean isoflavones and soybean saponins, and the outflowing liquid phase is water-soluble soybean oligosaccharides such as soybean stachyose and raffinose;

[0047] Step 8: Extract soybean stachyose and raffinose

[0048] The soybean stachyose and raffinose mixed liquid flowing out after macroporous resin adsorption in step 7 is pumped into the nanofiltration (nF) "membrane separation device". The membrane pore size is selected to be able to retain sugars with a relative molecular mass of more than 500, and the working pressure is 1.5Mpa, that is, raffinose with a relative molecular mass of 594 and stachyose with a relative molecular mass of 738 are retained, while sucrose (relative molecular mass of 342) and glucose with a relative molecular mass of less than 500 flow out through the filter membrane. The effluent can be discharged into the sewage treatment pool as liquid discharge for unified treatment, which does not belong to the content included in this patent.

[0049] The purity of stachyose and raffinose intercepted by the nanofiltration membrane (nF) is ≥25%. Through vacuum concentration, the water content is ≤25%, and the product can be directly filled into "stachyose and raffinose mixed syrup".

[0050] Step 9: Extract soybean saponin

[0051] Taking advantage of the biological characteristics that soybean saponins can be dissolved in water at room temperature below 60°C, while soybean isoflavones (including genistein and genistein) can only be dissolved in hot water above 80°C, the soybean saponins adsorbed on the macroporous resin in step 7 are eluted with water at room temperature below 60°C, and the eluent is a soybean saponin solution. After the soybean saponin solution is concentrated, the solid concentration reaches 10%, and after conventional sterilization, it is pumped into a spray drying tower, and the obtained solid powder with a moisture content of ≤7% is the soybean saponin;

[0052] Step 10: Extract soy isoflavones

[0053] The macroporous resin residue after eluting soybean saponin in step 9 is eluted 2 to 3 times with alkaline hot water with a temperature higher than 90°C and a pH value of 10 to 12, so that all the macroporous resin adsorbents are dissolved and eluted, and then the eluate is neutralized to pH 7.0 by adding food-grade hydrochloric acid. After desalting by an "electrodialysis device", it is sent to a cooling tank. The cooling tank is surrounded by a running water bath to reduce the temperature to below 20°C. Soybean genistein and genistein are precipitated and precipitated as a solid phase. The precipitated solid mixed solution is sent to a filter cloth with a pressure of 0.1Mpa to 0.3Mpa. In the target filter press, the solids obtained by filtration and interception at this time are crude soybean isoflavones;

[0054] Step 11: Second washing, separation, purification and drying

[0055] The crude soybean isoflavones obtained in step 10 are added with 20 to 30 times of purified water, and heated to above 90°C to dissolve the soybean isoflavones (including genistein and genistein). The solution at a temperature above 90°C is pumped into a filter cloth having a pressure of 0.2Mpa to 0.3Mpa. In the target filter press, the solid phase retained by the filter press is a non-water-soluble, non-isoflavone impurity, which can be used as a solid discharge material and used as feed or fertilizer. The permeate is concentrated to about 20% by a concentration device, and then the concentrated liquid is sent to a pressure spray drying tower, the tower inlet temperature is 170℃~180℃, the outlet temperature is 70℃~80℃, and the powder with a moisture content of ≤7% obtained by spray drying is the commodity "soy isoflavones (including genistein and genistein)".

[0056] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A method for extracting soybean isoflavones, soybean saponins, soybean stachyose and raffinose without the participation of organic chemical solvents, characterized in that: The following steps are involved: Step 1: Raw material selection Use low-temperature desolventized soybean meal after soybean oil soaking as raw material; Step 2: Alkaline hot water leaching The raw soybean meal of step 1 is fed into an extraction tank with a stirring heater, and pure water above 90°C is added to the extraction tank, the amount of water added is 5 to 10 times the weight of the soybean meal, and NaOH is added at the same time, and the pH is adjusted to 10 to 12, the stirring speed is 30 to 60 r / min, the stirring time is 4 to 6 hours, and the water temperature is maintained at 90°C to 100°C by using a heater; Step 3, sending the mixed liquid composed of soybean isoflavones dissolved in alkaline hot water above 90°C, soybean saponins, soybean stachyose and raffinose which are originally soluble in water at room temperature, and the solid phase soybean protein precipitated by heating to a 60-mesh sieve for filtration, and sending the sieved liquid to step 5, and the solid phase retentate to step 4; Step 4: Drying The solid phase retentate obtained by filtration and separation in step 3 is dried in a friction dryer, and the moisture content is ≤9%. The obtained product is "feed grade concentrated protein"; Step 5: Neutralization The liquid phase obtained by the screening machine in step 3 is sent to an insulated neutralization tank with a heating stirrer, and food-grade hydrochloric acid is added to adjust the pH to 7.0; Step 6: Desalination The neutral mixed liquid with a temperature of 90° C. and a pH of 7.0 obtained in step 5 is pumped into an electrodialysis desalination device, the feed pump pressure is 0.15 MPa to 0.25 MPa, the current of the electrodialysis device is 18 A to 20 A, and the conductivity of the mixed liquid after desalination should be 100 μs / cm to 300 μs / cm; Step 7: Resin adsorption The liquid phase obtained after electrodialysis and desalination in step 6 is sent to a macroporous resin adsorption device, and the components adsorbed by the resin are soybean isoflavones and soybean saponins, and the outflowing liquid phase is a water-soluble soybean oligosaccharide liquid containing soybean stachyose and raffinose; Step 8: Extract soybean stachyose and raffinose The soy oligosaccharide mixture liquid flowing out after adsorption by the macroporous resin in step 7 is pumped into the nanofiltration "membrane separation device", and the membrane pore size is selected to be able to intercept sugars with a relative molecular mass of more than 500, and the working pressure is 1.5Mpa, that is, raffinose with a relative molecular mass of 594 and stachyose with a relative molecular mass of 738 are intercepted, while sucrose and glucose with a relative molecular mass of less than 500 are allowed to flow out through the filter membrane; The purity of the sum of stachyose and raffinose intercepted by the nanofiltration membrane is ≥25%. Through vacuum concentration, the water content is ≤25%, and it can be directly filled as a "stachyose and raffinose mixed syrup" product; Step 9: Extract soybean saponin The soy saponin adsorbed on the macroporous resin in step 8 is eluted with water at a temperature of 60° C. The eluent is a soy saponin solution. After the soy saponin solution is concentrated, the solid concentration reaches 10%. After conventional sterilization, it is pumped into a spray drying tower. After drying, the solid powder with a moisture content of ≤7% is the soy saponin; Step 10: Extract soy isoflavones The macroporous resin adsorbent after eluting the soybean saponin in step 9 is eluted 2 to 3 times with alkaline hot water having a temperature higher than 90° C. and a pH of 10 to 12, so that the macroporous resin adsorbent is completely dissolved and eluted, and the eluate is neutralized to pH 7.0 by adding food-grade hydrochloric acid, and after desalination by electrodialysis, it is sent to a cooling tank, and the surrounding of the cooling tank is passed through a running water bath to cool down to below 20° C., soy isoflavones are precipitated and precipitated as a solid phase, and the precipitated solids and the mixed solution are sent together to a filter press with a pressure of 0.1Mpa to 0.3Mpa and a filter cloth of φ 200 mesh, and the solids intercepted by filtration are crude soy isoflavones containing impurities; Step 11: Second washing, separation, purification and drying The crude soy isoflavones obtained in step 10 are added with 20 to 30 times of water, heated to above 90°C, the soy isoflavones are dissolved, and the solution with a temperature of above 80°C is pumped into a filter press with a pressure of 0.2Mpa to 0.3Mpa and a filter cloth φ of 200 mesh. The solid phase retained by the filter press is water-insoluble, non-isoflavone impurities, which can be used as solid discharge, feed or fertilizer; the permeate is concentrated to 10% to 20% by a concentration device, and the concentrated solution is then sent to a pressure spray drying tower with an inlet temperature of 170°C to 180°C and an outlet temperature of 70°C to 80°C. The powder with a moisture content of ≤7% obtained by spray drying is the "soy isoflavones".