Method for preparing peanut protein powder
Through the process of multi-stage targeted extraction and composite precipitation separation, combined with phytase, composite protease and antioxidants, the problems of low peanut protein extraction rate, low purity and poor functional properties were solved, and efficient and pure peanut protein powder preparation was achieved.
Patent Information
- Application Number
- CN202510994443.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-18
- Publication Date
- 2025-10-10
AI Technical Summary
Existing peanut protein extraction methods have problems such as low extraction rate, protein denaturation, limited purity, residual anti-nutritional factors and single and extensive process, and fail to systematically solve the comprehensive problems of extraction rate, protein denaturation, purity and anti-nutritional factor removal.
A process of multi-stage targeted extraction, mild dynamic protection and composite precipitation separation is adopted, combined with phytase, composite protease, antioxidants and calcium ions, and pH and temperature are adjusted through multiple steps to separate different protein components, and antioxidant vitamin E and emblica extract are used to protect the protein.
It significantly improves the extraction rate and purity of peanut protein, maintains the natural structure and functional properties of protein, prevents oxidative denaturation, improves the solubility, emulsification and foaming properties of protein, and extends the shelf life of food.
Smart Images
Figure CN120753335A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of plant protein extraction, and particularly relates to a method for preparing peanut protein powder. Background Art
[0002] Peanuts are an important oil and protein resource. Peanut protein is highly nutritious, containing not only high-quality protein and healthy oils but also a well-balanced ratio of amino acids and fatty acids, providing essential nutrients for the human body. In addition to essential nutrients, peanuts are also rich in lecithin, purines, multiple vitamins, tocopherols, and minerals such as calcium and potassium. Peanuts also possess excellent functional properties, such as emulsification, gelation, and foaming properties, making them widely used in food, health supplements, and other fields. Currently, the mainstream method for extracting peanut protein is alkali dissolution and acid precipitation. However, this method has the following significant disadvantages: 1. Low extraction rate: It is difficult to fully dissolve different types of proteins (especially gluten) in peanuts through one-time alkaline extraction, resulting in some proteins remaining in the residue, and the overall extraction rate is usually less than 80%; 2. Protein variability: Strong alkali (high pH) and subsequent acid precipitation process (low pH) can easily lead to the destruction of protein structure and a significant decrease in functional properties (such as solubility and emulsification); 3. Limited protein purity: Non-protein impurities dissolved in the alkaline extract (such as polysaccharides, pigments, phytic acid, etc.) are difficult to effectively separate during acid precipitation, resulting in the purity (protein content) of the final protein product usually being below 90%; 4. Residual anti-nutritional factors: The removal effect of naturally occurring anti-nutritional factors in peanuts, such as phytic acid, is limited; 5. The process is single and extensive: There is a lack of targeted treatment of the solubility characteristics of different protein components.
[0003] While there are improvements in the prior art, such as enzyme-assisted and ultrasound-assisted methods, these methods often focus on optimizing a single process, such as improving alkali extraction efficiency or precipitation efficiency, and fail to systematically address the comprehensive issues of extraction rate, protein denaturation, purity, and removal of anti-nutritional factors. Furthermore, process complexity and costs may increase. Furthermore, the traditional extraction process is not protected by antioxidants, leading to oxidative denaturation of the protein. Without decolorization, the color and activity of the protein are poor. The present invention aims to provide a fundamentally innovative process route. Summary of the Invention
[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a peanut protein extraction process. The process significantly improves the extraction rate and purity of peanut protein through multi-stage targeted extraction, mild dynamic protection, composite precipitation separation, etc., has good antioxidant effect, and maintains the natural structure and functional properties of peanut protein to the greatest extent.
[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is: A method for preparing peanut protein powder comprises the following steps: (1) Using a vibration sorter to remove the red skin, the peanut kernels are subjected to physical oil extraction to obtain peanut oil and peanut defatted meal. The peanut defatted meal is mechanically crushed to obtain peanut defatted meal powder with a particle size of no more than 3 mm. The pH is adjusted to 5.0, and phytase is added to treat the peanut defatted meal powder for 60-90 minutes, and the supernatant is removed by centrifugation. (2) Disperse defatted peanut meal in water, adjust the pH to 7.0-7.5 with 0.3 mol / L sodium hydroxide solution, add composite protease, protective agent and antioxidant, and stir and extract at 40°C for 60 min. After the extraction, centrifuge at 10,000 rpm and 4°C for 10-15 min to obtain supernatant I and residue I containing albumin and globulin; (3) Resuspend the residue I in water, adjust the pH to 9.0 with 0.5 mol / L sodium hydroxide solution, extract with stirring at 45°C for 20-30 min, then heat to 50°C and extract with stirring for 40-60 min. After the extraction, centrifuge at 9000 rpm and 4°C for 10-15 min to obtain supernatant II and residue II rich in glutenin; (4) The supernatant I was subjected to low-temperature isoelectric precipitation: the pH was adjusted to 4.5 under stirring and ice-water bath cooling, and the solution was allowed to stand at room temperature for 60 min. The precipitate I was collected by centrifugation at 9000 rpm and 4°C. (5) The supernatant II was subjected to calcium ion-assisted isoelectric precipitation: the pH was adjusted to 5.0, 1 mM calcium chloride was added, and the pH was adjusted to 4.8-5.2. The supernatant II was allowed to stand at room temperature for 60 min, and then centrifuged at 9000 rpm at 4°C to collect the precipitate II. (6) Combine precipitate I and precipitate II and wash them 2-3 times with 4°C deionized water. Spray dry the washed protein precipitate and grind it through a 60-mesh sieve to obtain peanut protein powder.
[0006] Furthermore, in step (1), the mass ratio of defatted peanut meal to phytase is 100:0.01.
[0007] Furthermore, in step (2), the solid-liquid ratio of the defatted peanut meal to water is 1:10; and the mass ratio of the defatted peanut meal, compound protease, protective agent, and antioxidant is 100:0.5:1:0.05.
[0008] Furthermore, the protective agent is trehalose; the composite protease is neutral protease and flavor protease, and the mass ratio of the two is 1:1.
[0009] Furthermore, the antioxidant includes vitamin E and emblica officinalis extract, and the mass ratio of the two is 1:1.
[0010] Furthermore, in step (3), the solid-liquid ratio of the residue I to water is 1:8.
[0011] Furthermore, in step (4), the amount of calcium chloride added to the supernatant II is 5 mg / L.
[0012] Furthermore, the spray drying in step (6) adopts an inlet air temperature of 80-90°C and an atomization pressure of 0.3-0.5 MPa.
[0013] The peanut extraction process of the present invention incorporates antioxidants, including vitamin E and amla extract. Amla extract is rich in vitamin C, polyphenols, and other substances. The polyphenols in amla interact with proteins, significantly improving the emulsification and foaming properties of peanut protein. Plant polyphenols, as natural antioxidants, effectively scavenge free radicals, inhibit oxidative stress, and protect peanut protein from oxidative damage. Furthermore, polyphenols interact with proteins to alter their spatial conformation, enhancing thermal stability and mechanical properties. Plant polyphenols also possess antimicrobial activity, effectively delaying microbial contamination of peanut protein powder and extending the shelf life of the food. Vitamin E is considered a natural antioxidant, further meeting current consumer demand for "clean label" products. The amla extract (vitamin C and polyphenols) works synergistically with vitamin E to provide enhanced antioxidant protection.
[0014] The present invention adopts calcium salt as an auxiliary in the second stage of protein extraction, which significantly improves the precipitation efficiency and total yield of the protein, effectively improves the physical properties of the precipitate, reduces the water content, and facilitates subsequent operations.
[0015] When phytic acid combines with protein, it reduces the solubility, emulsification ability, foaming ability and other functional properties of the protein, seriously affecting the taste and texture of peanut protein. Phytase is added to the peanut protein extraction process of the present invention, and phytase can effectively decompose phytic acid.
[0016] The present invention maintains mild extraction temperatures at each stage, dynamically changing the temperature to enhance the efficient dissolution of gluten, reducing denaturation caused by sudden temperature changes, and calcium ion-assisted precipitation addresses the difficulty of separating high-density gluten. Furthermore, enzymatic hydrolysis and the addition of phytase enhance efficiency and improve nutritional quality.
[0017] Beneficial effects The present invention adds antioxidants during the peanut protein extraction process to effectively provide protection and prevent oxidative deterioration that begins during the processing. A step-by-step temperature increase strategy and the addition of protective agents and antioxidants are adopted to balance dissolution efficiency and protein protection.
[0018] The present invention splits the traditional alkaline extraction process into two targeted stages, optimizes the respective optimal extraction conditions according to the solubility characteristics of different proteins, significantly improves the dissolution rate of total protein, and especially solves the key problem of low gluten extraction rate.
[0019] The extraction steps of the present invention are not simply superimposed, but work synergistically with each other. The entire process design is closely linked to each other to achieve high extraction rate, high purity and high functionality of peanut protein powder. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 Scanning electron microscope images of the peanut protein powder prepared in Example 2 of the present invention and commercially available peanut protein powder. Note: Figure A is commercially available peanut protein powder, and Figure B is the peanut protein powder prepared in Example 2. DETAILED DESCRIPTION
[0021] The technical solution of the present invention will be further described below with reference to specific embodiments, but is not limited thereto.
[0022] Example 1 A method for preparing peanut protein powder comprises the following steps: (1) A vibration sorter was used to remove the red skin and the peanut kernels were subjected to physical oil extraction to obtain peanut oil and peanut defatted meal. The peanut defatted meal was mechanically crushed to obtain peanut defatted meal powder with a particle size of no more than 3 mm. The pH was adjusted to 5.0, and the peanut defatted meal powder was treated with phytase for 60 min, and the supernatant was removed by centrifugation. (2) Disperse defatted peanut meal in water, adjust the pH to 7.0 with 0.3 mol / L sodium hydroxide solution, add composite protease, protective agent and antioxidant, and stir and extract at 40°C for 60 min. After the extraction, centrifuge at 10,000 rpm and 4°C for 10 min to obtain supernatant I and residue I containing albumin and globulin; (3) Residue I was resuspended in water and the pH was adjusted to 9.0 with 0.5 mol / L sodium hydroxide solution. The mixture was first extracted at 45°C with stirring for 20 min, then heated to 50°C and extracted with stirring for 40 min. After the extraction, the mixture was centrifuged at 9000 rpm and 4°C for 10 min to obtain supernatant II and residue II rich in gluten. (4) The supernatant I was subjected to low-temperature isoelectric precipitation: the pH was adjusted to 4.5 under stirring and ice-water bath cooling, and the solution was allowed to stand at room temperature for 60 min. The precipitate I was collected by centrifugation at 9000 rpm and 4°C. (5) The supernatant II was subjected to calcium ion-assisted isoelectric precipitation: the pH was adjusted to 5.0, 1 mM calcium chloride was added, and the pH was adjusted to 5.2. The supernatant II was allowed to stand at room temperature for 60 min, and the precipitate II was collected by centrifugation at 9000 rpm at 4°C. (6) Combine precipitate I and precipitate II and wash them twice with 4°C deionized water. Spray dry the washed protein precipitate and grind it through a 60-mesh sieve to obtain peanut protein powder.
[0023] In the step (1), the mass ratio of defatted peanut meal to phytase is 100:0.01.
[0024] In the step (2), the solid-liquid ratio of the defatted peanut meal to water is 1:10; the mass ratio of the defatted peanut meal, compound protease, protective agent, and antioxidant is 100:0.5:1:0.05.
[0025] The protective agent is trehalose; the composite protease is neutral protease and flavor protease, and the mass ratio of the two is 1:1.
[0026] The antioxidant comprises vitamin E and emblica officinalis extract, and the mass ratio of the two is 1:1.
[0027] In step (3), the solid-to-liquid ratio of the residue I to water is 1:8.
[0028] In step (4), the amount of calcium chloride added to the supernatant II is 5 mg / L.
[0029] The spray drying in step (6) adopts an inlet air temperature of 90° C. and an atomization pressure of 0.3 MPa.
[0030] Example 2 A method for preparing peanut protein powder comprises the following steps: (1) A vibration sorter was used to remove the red skin and the peanut kernels were subjected to physical oil extraction to obtain peanut oil and peanut defatted meal. The peanut defatted meal was mechanically crushed to obtain peanut defatted meal powder with a particle size of no more than 3 mm. The pH was adjusted to 5.0, and the peanut defatted meal powder was treated with phytase for 90 min, and the supernatant was removed by centrifugation. (2) Disperse defatted peanut meal in water, adjust the pH to 7.5 with 0.3 mol / L sodium hydroxide solution, add composite protease, protective agent and antioxidant, and stir and extract at 40°C for 60 min. After the extraction, centrifuge at 10,000 rpm and 4°C for 15 min to obtain supernatant I and residue I containing albumin and globulin; (3) Resuspend the residue I in water, adjust the pH to 9.0 with 0.5 mol / L sodium hydroxide solution, extract with stirring at 45°C for 30 min, then heat to 50°C and extract with stirring for 60 min. After the extraction, centrifuge at 9000 rpm and 4°C for 15 min to obtain the supernatant II and residue II rich in glutenin; (4) The supernatant I was subjected to low-temperature isoelectric precipitation: the pH was adjusted to 4.5 under stirring and ice-water bath cooling, and the solution was allowed to stand at room temperature for 60 min. The precipitate I was collected by centrifugation at 9000 rpm and 4°C. (5) The supernatant II was subjected to calcium ion-assisted isoelectric precipitation: the pH was adjusted to 5.0, 1 mM calcium chloride was added, and the pH was adjusted to 4.8. The supernatant II was allowed to stand at room temperature for 60 min, and the precipitate II was collected by centrifugation at 9000 rpm at 4°C. (6) Combine precipitate I and precipitate II and wash them three times with 4°C deionized water. Spray dry the washed protein precipitate and grind it through a 60-mesh sieve to obtain peanut protein powder.
[0031] In the step (1), the mass ratio of defatted peanut meal to phytase is 100:0.01.
[0032] In the step (2), the solid-liquid ratio of the defatted peanut meal to water is 1:10; the mass ratio of the defatted peanut meal, compound protease, protective agent, and antioxidant is 100:0.5:1:0.05.
[0033] The protective agent is trehalose; the composite protease is neutral protease and flavor protease, and the mass ratio of the two is 1:1.
[0034] The antioxidant comprises vitamin E and emblica officinalis extract, and the mass ratio of the two is 1:1.
[0035] In step (3), the solid-to-liquid ratio of the residue I to water is 1:8.
[0036] In step (4), the amount of calcium chloride added to the supernatant II is 5 mg / L.
[0037] The spray drying in step (6) adopts an inlet air temperature of 80° C. and an atomization pressure of 0.5 MPa.
[0038] Scanning electron microscope was used to observe the microstructure of the present embodiment and commercially available protein powder. Figure 1 As shown, the sample magnified 2.00K times basically exists in a folded or wrinkled spherical form. The particles of the commercially available protein powder (Figure A) are large and obviously aggregated. The aggregation state of the peanut protein powder prepared in this example (Figure B) is improved, and the protein powder surface is evenly distributed and has a loose structure.
[0039] Comparative Example 1 A method for preparing peanut protein powder comprises the following steps: (1) A vibration sorter was used to remove the red skin and the peanut kernels were subjected to physical oil extraction to obtain peanut oil and peanut defatted meal. The peanut defatted meal was mechanically crushed to obtain peanut defatted meal powder with a particle size of no more than 3 mm. The pH was adjusted to 5.0, and the peanut defatted meal powder was treated with phytase for 90 min, and the supernatant was removed by centrifugation. (2) Disperse defatted peanut meal in water, adjust the pH to 7.5 with 0.3 mol / L sodium hydroxide solution, add composite protease, protective agent and antioxidant, and stir and extract at 40°C for 60 min. After the extraction, centrifuge at 10,000 rpm and 4°C for 15 min to obtain supernatant I and residue I containing albumin and globulin; (3) Resuspend the residue I in water, adjust the pH to 9.0 with 0.5 mol / L sodium hydroxide solution, extract with stirring at 45°C for 30 min, then heat to 50°C and extract with stirring for 60 min. After the extraction, centrifuge at 9000 rpm and 4°C for 15 min to obtain the supernatant II and residue II rich in glutenin; (4) The supernatant I was subjected to low-temperature isoelectric precipitation: the pH was adjusted to 4.5 under stirring and ice-water bath cooling, and the solution was allowed to stand at room temperature for 60 min. The precipitate I was collected by centrifugation at 9000 rpm and 4°C. (5) The supernatant II was subjected to calcium ion-assisted isoelectric precipitation: the pH was adjusted to 5.0, 1 mM calcium chloride was added, and the pH was adjusted to 4.8. The supernatant II was allowed to stand at room temperature for 60 min, and the precipitate II was collected by centrifugation at 9000 rpm at 4°C. (6) Combine precipitate I and precipitate II and wash them three times with 4°C deionized water. Spray dry the washed protein precipitate and grind it through a 60-mesh sieve to obtain peanut protein powder.
[0040] In the step (1), the mass ratio of defatted peanut meal to phytase is 100:0.01.
[0041] In the step (2), the solid-liquid ratio of the defatted peanut meal to water is 1:10; the mass ratio of the defatted peanut meal, compound protease, protective agent, and antioxidant is 100:0.5:1:0.05.
[0042] The protective agent is trehalose; the composite protease is neutral protease and flavor protease, and the mass ratio of the two is 1:1.
[0043] The antioxidant includes vitamin E.
[0044] In step (3), the solid-to-liquid ratio of the residue I to water is 1:8.
[0045] In step (4), the amount of calcium chloride added to the supernatant II is 5 mg / L.
[0046] The spray drying in step (6) adopts an inlet air temperature of 80° C. and an atomization pressure of 0.5 MPa.
[0047] Compared with Example 2, this comparative example is the same as Example 2 except that the emblica extract is not added as the antioxidant. The other raw materials and steps are the same as Example 2.
[0048] Comparative Example 2 A method for preparing peanut protein powder comprises the following steps: (1) A vibration sorter was used to remove the red skin and the peanut kernels were subjected to physical oil extraction to obtain peanut oil and peanut defatted meal. The peanut defatted meal was mechanically crushed to obtain peanut defatted meal powder with a particle size of no more than 3 mm. The pH was adjusted to 5.0, and the peanut defatted meal powder was treated with phytase for 90 min, and the supernatant was removed by centrifugation. (2) Disperse defatted peanut meal in water, adjust the pH to 7.5 with 0.3 mol / L sodium hydroxide solution, add composite protease and protective agent, and stir and extract at 40°C for 60 min. After the extraction, centrifuge at 10,000 rpm and 4°C for 15 min to obtain supernatant I and residue I containing albumin and globulin; (3) Resuspend the residue I in water, adjust the pH to 9.0 with 0.5 mol / L sodium hydroxide solution, extract with stirring at 45°C for 30 min, then heat to 50°C and extract with stirring for 60 min. After the extraction, centrifuge at 9000 rpm and 4°C for 15 min to obtain the supernatant II and residue II rich in glutenin; (4) The supernatant I was subjected to low-temperature isoelectric precipitation: the pH was adjusted to 4.5 under stirring and ice-water bath cooling, and the solution was allowed to stand at room temperature for 60 min. The precipitate I was collected by centrifugation at 9000 rpm and 4°C. (5) The supernatant II was subjected to calcium ion-assisted isoelectric precipitation: the pH was adjusted to 5.0, 1 mM calcium chloride was added, and the pH was adjusted to 4.8. The supernatant II was allowed to stand at room temperature for 60 min, and the precipitate II was collected by centrifugation at 9000 rpm at 4°C. (6) Combine precipitate I and precipitate II and wash them three times with 4°C deionized water. Spray dry the washed protein precipitate and grind it through a 60-mesh sieve to obtain peanut protein powder.
[0049] In the step (1), the mass ratio of defatted peanut meal to phytase is 100:0.01.
[0050] In the step (2), the solid-liquid ratio of the defatted peanut meal to water is 1:10; the mass ratio of the defatted peanut meal, compound protease, and protective agent is 100:0.5:1.
[0051] The protective agent is trehalose; the composite protease is neutral protease and flavor protease, and the mass ratio of the two is 1:1.
[0052] In step (3), the solid-to-liquid ratio of the residue I to water is 1:8.
[0053] In step (4), the amount of calcium chloride added to the supernatant II is 5 mg / L.
[0054] The spray drying in step (6) adopts an inlet air temperature of 80° C. and an atomization pressure of 0.5 MPa.
[0055] Compared with Example 2, this comparative example is the same as Example 2 except that no antioxidant is added.
[0056] Comparative Example 3 A method for preparing peanut protein powder comprises the following steps: (1) A vibration sorter was used to remove the red skin and the peanut kernels were subjected to physical oil extraction to obtain peanut oil and peanut defatted meal. The peanut defatted meal was mechanically crushed to obtain peanut defatted meal powder with a particle size of no more than 3 mm. The pH was adjusted to 5.0, and the peanut defatted meal powder was treated with phytase for 90 min, and the supernatant was removed by centrifugation. (2) Disperse defatted peanut meal in water, adjust the pH to 9.0 with sodium hydroxide solution, add composite protease, protective agent and antioxidant, stir and extract for 2.5 hours, centrifuge at 10,000 r / min and 4°C for 15 minutes to obtain supernatant, collect the supernatant and adjust the pH to 4.5, let it stand at room temperature for 60 minutes, centrifuge at 9,000 r / min and 4°C to collect the precipitate, wash it three times with 4°C deionized water, spray dry the washed protein precipitate, and grind it through a 60-mesh sieve to obtain peanut protein powder.
[0057] In the step (1), the mass ratio of defatted peanut meal to phytase is 100:0.01.
[0058] In the step (2), the solid-liquid ratio of the defatted peanut meal to water is 1:10; the mass ratio of the defatted peanut meal, compound protease, protective agent, and antioxidant is 100:0.5:1:0.05.
[0059] The protective agent is trehalose; the composite protease is neutral protease and flavor protease, and the mass ratio of the two is 1:1.
[0060] The antioxidant comprises vitamin E and emblica officinalis extract, and the mass ratio of the two is 1:1.
[0061] The spray drying in step (2) adopts an inlet air temperature of 80° C. and an atomization pressure of 0.5 MPa.
[0062] Compared with Example 2, this comparative example uses the same raw materials and steps as Example 2, except that the protein extraction stage adopts a one-step extraction method (i.e., conventional alkali dissolution and acid precipitation method).
[0063] Comparative Example 4 A method for preparing peanut protein powder comprises the following steps: (1) A vibration sorter was used to remove the red skin and the peanut kernels were subjected to physical oil extraction to obtain peanut oil and peanut defatted meal. The peanut defatted meal was mechanically crushed to obtain peanut defatted meal powder with a particle size of no more than 3 mm. The pH was adjusted to 5.0, and the peanut defatted meal powder was treated with phytase for 90 min, and the supernatant was removed by centrifugation. (2) Disperse defatted peanut meal in water, adjust the pH to 7.5 with 0.3 mol / L sodium hydroxide solution, add composite protease, protective agent and antioxidant, and stir and extract at 40°C for 60 min. After the extraction, centrifuge at 10,000 rpm and 4°C for 15 min to obtain supernatant I and residue I containing albumin and globulin; (3) Resuspend the residue I in water, adjust the pH to 9.0 with 0.5 mol / L sodium hydroxide solution, extract with stirring at 45°C for 30 min, then heat to 50°C and extract with stirring for 60 min. After the extraction, centrifuge at 9000 rpm and 4°C for 15 min to obtain the supernatant II and residue II rich in glutenin; (4) The supernatant I was subjected to low-temperature isoelectric precipitation: the pH was adjusted to 4.5 under stirring and ice-water bath cooling, and the solution was allowed to stand at room temperature for 60 min. The precipitate I was collected by centrifugation at 9000 rpm and 4°C. (5) The supernatant II was subjected to isoelectric precipitation: the pH was adjusted to 4.8, the solution was allowed to stand at room temperature for 60 min, and the precipitate II was collected by centrifugation at 9000 rpm at 4°C. (6) Combine precipitate I and precipitate II and wash them three times with 4°C deionized water. Spray dry the washed protein precipitate and grind it through a 60-mesh sieve to obtain peanut protein powder.
[0064] In the step (1), the mass ratio of defatted peanut meal to phytase is 100:0.01.
[0065] In the step (2), the solid-liquid ratio of the defatted peanut meal to water is 1:10; the mass ratio of the defatted peanut meal, compound protease, protective agent, and antioxidant is 100:0.5:1:0.05.
[0066] The protective agent is trehalose; the composite protease is neutral protease and flavor protease, and the mass ratio of the two is 1:1.
[0067] The antioxidant comprises vitamin E and emblica officinalis extract, and the mass ratio of the two is 1:1.
[0068] In step (3), the solid-to-liquid ratio of the residue I to water is 1:8.
[0069] The spray drying in step (6) adopts an inlet air temperature of 80° C. and an atomization pressure of 0.5 MPa.
[0070] The comparative example is compared with example 2, except that step (5) is not assisted by calcium chloride auxiliary precipitation, and the rest of the raw materials and steps are the same as example 2.
[0071] Performance test The peanut variety for testing is Shandong Lu Hua 11 peanut, and the extraction rate, purity and functional properties of peanut protein extracted by the extraction processes of examples 1-2 and comparative examples 1-4 are determined.
[0072] Extraction rate of peanut protein: the percentage of protein mass in protein product to protein mass in raw material; Purity of peanut protein: the sample protein is made into a protein solution of 0.1 mg / mL, ultrasonic is performed at 400 W and 45°C for 40 min, centrifugation is performed at 8000 r / min for 5 min, 2 mL supernatant is taken in 10 mL centrifuge, 5 mL coomassie brilliant blue solution is added in the dark, the absorbance value is measured at 595 nm after reaction for 5 min, and the protein content is calculated in the standard curve equation (y=8.9350x+0.5723, R 2 =0.9993, in which: x is absorbance value, y is protein content) determined by bovine serum albumin as standard. The protein purity (Y) is calculated according to formula (2). Y=C / C0x100%, in which: C is the protein content in supernatant, mg / mL; C0is the mass concentration of protein solution, mg / mL.
[0073] Functional property determination Solubility: the protein content is determined by Kjeldahl method, and the calculation formula of protein solubility is as follows according to GB5009.5-2016: protein solubility (%) = W1 / W2x100%, in which W1is the protein content in aqueous solution; W2is the protein content of protein powder; Emulsifying property: 0.15 g of peanut protein (calculated by protein) is weighed, high-speed shearing is performed at 11 000 r / min for 30 s, centrifugation is performed at 5 000 r / min, the emulsion layer height and the total liquid height in the tube are recorded, and the emulsifying property is the ratio of the emulsion layer height to the liquid height in the centrifuge tube (%). The centrifuge tube is placed in a water bath at 80°C for heating for 30 min, and then cooled to room temperature, and the above steps are measured, and the emulsion stability is the ratio of the emulsion layer height to the liquid height in the tube (%).
[0074] Foaming property and foam stability: a peanut protein solution of 20 mg / mL is prepared with a volume of V0(calculated by protein), the foam volume V1is recorded after shearing; the foam volume V2is recorded again after standing at room temperature for 30 min, and the foaming property and foam stability of peanut protein are calculated according to the following formula: foaming property (%) = V1 / V0x100; foam stability (%) = V2 / V0x100; Water-holding capacity: Weigh a certain mass of protein from each treatment group (m0) into a 10 mL centrifuge tube. The total mass of the protein and the centrifuge tube (m1) is then measured. Add 10 mL of distilled water to the tube, let it stand at room temperature for 30 minutes, and centrifuge at 8,000 rpm for 10 minutes. Remove the water from the supernatant and weigh the total mass of the precipitate and the centrifuge tube (m2). The water-holding capacity of the protein is calculated using the formula: Water-holding capacity = (m2 - m1) / m0 × 100%.
[0075] Table 1 Test results of peanut protein prepared by different extraction methods As shown in Table 1, the peanut proteins prepared using the extraction processes of Examples 1 and 2 of the present invention exhibited excellent extraction yield, purity, and functional properties. Comparative Example 3, compared to Example 2, exhibited a significant decrease in protein extraction yield and purity after switching to a one-step protein extraction process. The functional properties of the peanut proteins extracted in Comparative Examples 1 and 2 were significantly lower than those in Example 2, particularly in terms of solubility, emulsification, and foaming properties, indicating that the added antioxidant component effectively improved the functional properties of the protein.
[0076] It should be noted that the above embodiments are only some of the preferred embodiments of the present invention, and not all of them. Obviously, based on the above embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work should fall within the scope of protection of the present invention.
Claims
1. A method for preparing peanut protein powder, characterized in that, The following steps are involved: (1) Using a vibration sorter to remove the red skin, the peanut kernels are subjected to physical oil extraction to obtain peanut oil and peanut defatted meal. The peanut defatted meal is mechanically crushed to obtain peanut defatted meal powder with a particle size of no more than 3 mm. The pH is adjusted to 5.0, and phytase is added to treat the peanut defatted meal powder for 60-90 minutes, and the supernatant is removed by centrifugation. (2) Disperse defatted peanut meal in water, adjust the pH to 7.0-7.5 with 0.3 mol / L sodium hydroxide solution, add composite protease, protective agent and antioxidant, and stir and extract at 40°C for 60 min. After the extraction, centrifuge at 10,000 rpm and 4°C for 10-15 min to obtain supernatant I and residue I containing albumin and globulin; (3) Resuspend the residue I in water, adjust the pH to 9.0 with 0.5 mol / L sodium hydroxide solution, extract with stirring at 45°C for 20-30 min, then heat to 50°C and extract with stirring for 40-60 min. After the extraction, centrifuge at 9000 rpm and 4°C for 10-15 min to obtain supernatant II and residue II rich in glutenin; (4) The supernatant I was subjected to low-temperature isoelectric precipitation: the pH was adjusted to 4.5 under stirring and ice-water bath cooling, and the solution was allowed to stand at room temperature for 60 min. The precipitate I was collected by centrifugation at 9000 rpm and 4°C. (5) The supernatant II was subjected to calcium ion-assisted isoelectric precipitation: the pH was adjusted to 5.0, 1 mM calcium chloride was added, and the pH was adjusted to 4.8-5.
2. The supernatant II was allowed to stand at room temperature for 60 min, and then centrifuged at 9000 rpm at 4°C to collect the precipitate II. (6) Combine precipitate I and precipitate II and wash them 2-3 times with 4°C deionized water. Spray dry the washed protein precipitate and grind it through a 60-mesh sieve to obtain peanut protein powder.
2. The method for preparing peanut protein powder according to claim 1, wherein In the step (1), the mass ratio of defatted peanut meal to phytase is 100:0.
01.
3. The method for preparing peanut protein powder according to claim 1, wherein In the step (2), the solid-liquid ratio of the defatted peanut meal to water is 1:10; the mass ratio of the defatted peanut meal, compound protease, protective agent, and antioxidant is 100:0.5:1:0.
05.
4. The method for preparing peanut protein powder according to claim 3, wherein The protective agent is trehalose; the composite protease is neutral protease and flavor protease, and the mass ratio of the two is 1:
1.
5. The method for preparing peanut protein powder according to claim 1, wherein The antioxidant comprises vitamin E and emblica officinalis extract, and the mass ratio of the two is 1:
1.
6. The method for preparing peanut protein powder according to claim 1, wherein In step (3), the solid-to-liquid ratio of the residue I to water is 1:
8.
7. The method for preparing peanut protein powder according to claim 1, wherein In step (4), the amount of calcium chloride added to the supernatant II is 5 mg / L.
8. The method for preparing peanut protein powder according to claim 1, wherein The spray drying in step (6) adopts an inlet air temperature of 80-90° C. and an atomization pressure of 0.3-0.5 MPa.