Method for improving flavor of peanut oil prepared by aqueous enzymatic method

Abstract

The invention discloses a method for improving the flavor of peanut oil prepared by an aqueous enzymatic method, and belongs to the technical field of peanut oil processing. The method comprises the following steps: (1) screening raw materials; (2) crushing; (3) ultrasonic pretreatment; (4) performing enzymolysis; (5) carrying out microwave demulsification on the emulsified oil layer; (6) alkali extraction and acid precipitation; (7) performing secondary enzymolysis; and (8) temperature-controlled heating. According to the method, the oil is prepared by adopting an aqueous enzymatic method, the integrity and functional characteristics of peanut protein are well maintained, meanwhile, the flavor of the peanut oil is remarkably increased by adopting the technical means of grading treatment of intermediate products, secondary enzymolysis, temperature-controlled heating and the like and utilizing a Maillard reaction product, high-quality utilization of peanut oil and protein is comprehensively realized, and the method is suitable for industrial production. The problem that the flavor of the aqueous enzymatic method peanut oil is not prominent is solved.

Description

Technical Field

[0001] The present invention relates to a method for improving the flavor of peanut oil prepared by the aqueous enzymatic method, belonging to the technical field of peanut oil processing. Background Art

[0002] The aqueous enzymatic oil extraction method is based on the physical pulverization of peanut kernels, adding enzymes that can decompose cell walls, lipoproteins, and lipopolysaccharides in oilseeds, destroying the tissue structure, so that oils and proteins are fully released, and using their hydrophilic and lipophilic differences, and completing the separation of oils and proteins by mechanical means such as centrifugation.

[0003] During the aqueous enzymatic oil extraction process, to ensure the integrity and functional properties of proteins, a relatively low enzyme treatment temperature is often used, while the flavor of peanut oil is mainly presented by the Maillard reaction of proteins, amino acids, and reducing sugars contained in peanuts under high temperature, generating volatile substances such as aldehydes and pyrazines. Due to the low temperature, the peanut oil prepared by the aqueous enzymatic method often has the disadvantage of unremarkable flavor. Therefore, how to obtain peanut oil with better flavor while separating complete functional proteins is a current research hotspot. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a method for improving the flavor of peanut oil prepared by the aqueous enzymatic method, which can not only improve the flavor of peanut oil, obtain peanut oil with prominent flavor, but also obtain proteins with complete functionality.

[0005] To solve the above technical problems, the technical solution provided by the present invention is: A method for improving the flavor of peanut oil prepared by the aqueous enzymatic method, comprising the following steps: (1) Raw material screening: removing impurities and mildewed peanut kernels from peanuts to obtain the screened peanut kernels; (2) Pulverization: pulverizing the screened peanut kernels with a high-speed pulverizer for 30 s, and sieving to obtain peanut powder; (3) Ultrasonic pretreatment: mixing peanut powder with water, and stirring at room temperature for 30 - 60 min under ultrasonic assistance to obtain a mixed solution; (4) Enzymolysis: adding a mixed enzyme to the mixed solution, reacting at 40 - 60 °C for 2 - 4 h, then placing it in boiling water to inactivate the enzyme for 10 - 15 min, cooling to room temperature, and then centrifuging for 15 - 25 min to obtain an emulsified oil layer with high oil content and an enzymolysis solution; (5) Microwave demulsification of the emulsified oil layer: subjecting the emulsified oil layer with high oil content to microwave treatment, and then centrifuging to obtain clear oil; (6) Alkaline extraction and acid precipitation: Divide the enzymatic hydrolysate into enzymatic hydrolysate A and enzymatic hydrolysate B. Adjust the pH of enzymatic hydrolysate A to 9.0 - 9.5 with 2 mol / L sodium hydroxide solution, perform alkaline extraction for 20 - 50 min, then adjust the pH to 4.0 - 5.0 with 2 mol / L hydrochloric acid solution, perform acid precipitation for 10 - 15 min, and then centrifuge at 4000 - 8000 r / min for 15 - 30 min to obtain protein and precipitate; (7) Secondary enzymatic hydrolysis: Mix the precipitate with enzymatic hydrolysate B, add amylase and protease for secondary enzymatic hydrolysis to obtain secondary enzymatic hydrolysis product; (8) Temperature-controlled heating: Mix the secondary enzymatic hydrolysis product with refined oil and perform temperature-controlled heating to obtain peanut oil with rich flavor.

[0006] Further, in step (2), the peanut powder is obtained by sieving through a 400-mesh sieve.

[0007] Further, in step (3), the mass ratio of the peanut powder to water is 1:5.

[0008] Further, in step (4), the addition amount of the mixed enzyme is 2 - 5% of the mass of the mixed solution.

[0009] Further, in step (4), the mixed enzyme is a mixture of pectinase, cellulase, and hemicellulase with a mass ratio of 4:2:1.

[0010] Further, in step (4), the rotation speed of the centrifugation is 5000 - 6000 r / min.

[0011] Further, in step (4), the enzymatic hydrolysate includes peanut protein and carbohydrates.

[0012] Further, in step (5), the power of the microwave treatment is 500 - 800 W, and the time of the microwave treatment is 40 - 80 s; the rotation speed of the centrifugation is 4000 - 8000 r / min, and the time of the centrifugation is 15 - 30 min.

[0013] Further, in step (6), the volume ratio of enzymatic hydrolysate A to enzymatic hydrolysate B is 1:1. Enzymatic hydrolysate A extracts complete protein, and enzymatic hydrolysate B provides protein to react with other substances to generate various flavor substances, significantly increasing the content of oil flavor substances.

[0014] Further, in step (7), the temperature of the secondary enzymatic hydrolysis is 50 - 60 °C, and the time is 30 min. After secondary enzymatic hydrolysis, reducing sugars and amino compounds are obtained. Subsequently, after mixing with refined oil, the reducing sugars and amino compounds can undergo Maillard reaction at high temperature to generate various flavor substances, significantly increasing the content of oil flavor substances.

[0015] Further, in step (7), the total addition amount of the amylase and protease is 0.5% of the mass of enzymatic hydrolysate B; the mass ratio of the amylase to the protease is 1:1.

[0016] Further, in step (8), the temperature of the temperature-controlled heating is 140 - 160 °C, and the time of the temperature-controlled heating is 4 - 6 min.

[0017] In the present invention, by subjecting fully crushed peanuts to ultrasonic pretreatment, the components of the cell wall itself and the physical binding with protein and oil components can be fully destroyed. Using cell wall enzymes such as pectinase, cellulase, and hemicellulase for aqueous enzymatic oil extraction, and supplemented with physical separation techniques, clear oil and peanut protein + carbohydrate precipitate are obtained. The peanut protein + carbohydrate precipitate is divided into two parts. One part is used to prepare complete protein by alkali extraction and acid precipitation. The remaining carbohydrate residue is mixed with the other part of the precipitate, and amylase and protease are added. After enzymatic hydrolysis, reducing sugar and amino compounds are obtained, and then mixed with the clear oil. The reducing sugar and amino compounds undergo Maillard reaction under temperature-controlled heating to generate various flavor substances, significantly increasing the content of flavor substances in the oil. The present invention can retain the complete protein in peanuts while extracting peanut oil, and effectively improve the content of flavor substances in peanut oil, which is beneficial to the comprehensive utilization of products.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The present invention adopts aqueous enzymatic oil extraction, which better maintains the integrity and functional properties of peanut protein. At the same time, through the hierarchical treatment of intermediate products, by means of techniques such as secondary enzymatic hydrolysis and temperature-controlled heating, the Maillard reaction products are used to significantly increase the flavor of peanut oil, comprehensively realizing the high-quality utilization of peanut oil and protein, and solving the problem that the flavor of aqueous enzymatic peanut oil is often not prominent.

[0019] (2) The process of the present invention realizes the retention of complete protein in peanuts while extracting peanut oil, and effectively improves the content of flavor substances in peanut oil, which is beneficial to the comprehensive utilization of products. It is a great progress in aqueous enzymatic oil extraction in the prior art and is beneficial to the industrial production and utilization of peanut oil.

[0020] (3) The method of the present invention is simple and easy to use, realizes the comprehensive and full utilization of various components in peanuts, reduces the production cost of peanut oil, and reduces the generation of waste. Description of the Drawings

[0021] Figure 1 is a flow chart of the process method of the present invention. Detailed Embodiments

[0022] Example 1 A method for improving the flavor of peanut oil prepared by aqueous enzymatic method, comprising the following steps: (1)Raw material screening: Remove impurities and moldy peanuts from the peanut kernels to obtain the screened peanut kernels; (2)Crushing: Crush the screened peanut kernels with a high-speed crusher for 30 s and pass through a 400-mesh sieve to obtain peanut powder; (3)Ultrasonic pretreatment: Mix the peanut powder and water at a mass ratio of 1:5 and stir at room temperature for 30 - 60 min under ultrasonic assistance to obtain a mixed solution; (4)Enzymatic hydrolysis: Add a mixed enzyme to the mixed solution. The addition amount of the mixed enzyme is 4% of the mass of the mixed solution. The mixed enzyme is a mixture of pectinase, cellulase, and hemicellulase at a mass ratio of 4:2:1. React at 50 °C for 3 h, then place it in boiling water to inactivate the enzyme for 10 min, cool to room temperature, and then centrifuge at a speed of 5000 r / min for 20 min to obtain an emulsified oil layer with a high oil content and an enzymatic hydrolysate; (5)Microwave demulsification of the emulsified oil layer: Treat the emulsified oil layer with a high oil content under 600 W microwave conditions for 60 s, and then centrifuge at 6000 r / min for 20 min to obtain clear oil; (6)Alkali extraction and acid precipitation: Divide the enzymatic hydrolysate into enzymatic hydrolysate A and enzymatic hydrolysate B. The volume ratio of enzymatic hydrolysate A to enzymatic hydrolysate B is 1:1. Adjust the pH of enzymatic hydrolysate A to 9.0 - 9.5 with a 2 mol / L sodium hydroxide solution, perform alkali extraction for 40 min, then adjust the pH to 4.0 - 5.0 with a 2 mol / L hydrochloric acid solution, perform acid precipitation for 15 min, and then centrifuge at 6000 r / min for 20 min to obtain protein and precipitate; (7)Secondary enzymatic hydrolysis: Mix the precipitate with enzymatic hydrolysate B, add amylase and protease. The mass ratio of amylase to protease is 1:1, and the total addition amount is 0.5% of the mass of enzymatic hydrolysate B. Perform secondary enzymatic hydrolysis at 50 °C for 30 min to obtain a secondary enzymatic hydrolysis product; (8)Temperature-controlled heating: After mixing the secondary enzymatic hydrolysis product and the clear oil, perform temperature-controlled heating at 140 °C for 5 min to obtain peanut oil with a rich flavor.

[0023] Example 2 A method for improving the flavor of peanut oil prepared by the aqueous enzymatic method, comprising the following steps: (1)Raw material screening: Remove impurities and moldy peanuts from the peanut kernels to obtain the screened peanut kernels; (2)Crushing: Crush the screened peanut kernels with a high-speed crusher for 30 s and pass through a 400-mesh sieve to obtain peanut powder; (3)Ultrasonic pretreatment: Mix the peanut powder and water at a mass ratio of 1:5 and stir at room temperature for 45 min under ultrasonic assistance to obtain a mixed solution; (4)Enzymatic hydrolysis: Add a mixed enzyme to the mixed solution. The addition amount of the mixed enzyme is 3% of the mass of the mixed solution. The mixed enzyme is a mixture of pectinase, cellulase, and hemicellulase with a mass ratio of 4:2:1. React at 50 °C for 3 h, then place it in boiling water to inactivate the enzyme for 15 min, cool to room temperature, and then centrifuge at a speed of 6000 r / min for 15 min to obtain an emulsified oil layer with a high oil content and an enzymatic hydrolysate; (5)Microwave demulsification of the emulsified oil layer: Treat the emulsified oil layer with a high oil content under 500 W microwave conditions for 80 s, and then centrifuge at 4000 r / min for 30 min to obtain clear oil; (6)Alkali extraction and acid precipitation: Divide the enzymatic hydrolysate into enzymatic hydrolysate A and enzymatic hydrolysate B. The volume ratio of enzymatic hydrolysate A to enzymatic hydrolysate B is 1:1. Adjust the pH of enzymatic hydrolysate A to 9.0 - 9.5 with a 2 mol / L sodium hydroxide solution, perform alkali extraction for 50 min, then adjust the pH to 4.0 - 5.0 with a 2 mol / L hydrochloric acid solution, perform acid precipitation for 10 min, and then centrifuge at 4000 r / min for 30 min to obtain protein and precipitate; (7)Secondary enzymatic hydrolysis: Mix the precipitate with enzymatic hydrolysate B, add amylase and protease. The mass ratio of amylase to protease is 1:1, and the total addition amount is 0.5% of the mass of enzymatic hydrolysate B. Perform secondary enzymatic hydrolysis at 60 °C for 30 min to obtain a secondary enzymatic hydrolysis product; (8)Temperature-controlled heating: After mixing the secondary enzymatic hydrolysis product with the clear oil, perform temperature-controlled heating at 145 °C for 4 min to obtain peanut oil with a rich flavor.

[0024] Example 3 A method for improving the flavor of peanut oil prepared by the aqueous enzymatic method, comprising the following steps: (1)Raw material screening: Remove impurities and moldy peanuts from the peanut kernels to obtain the screened peanut kernels; (2)Crushing: Crush the screened peanut kernels with a high-speed crusher for 30 s and pass through a 400-mesh sieve to obtain peanut powder; (3)Ultrasonic pretreatment: Mix the peanut powder and water at a mass ratio of 1:5, and stir at room temperature for 40 min under ultrasonic assistance to obtain a mixed solution; (4)Enzymatic hydrolysis: Add a mixed enzyme to the mixed solution. The addition amount of the mixed enzyme is 5% of the mass of the mixed solution. The mixed enzyme is a mixture of pectinase, cellulase, and hemicellulase with a mass ratio of 4:2:1. React at 50 °C for 3 h, then place it in boiling water to inactivate the enzyme for 10 min, cool to room temperature, and then centrifuge at a speed of 5500 r / min for 25 min to obtain an emulsified oil layer with a high oil content and an enzymatic hydrolysate; (5)Microwave demulsification of the emulsified oil layer: Treat the emulsified oil layer with a high oil content under 800 W microwave conditions for 40 s, and then centrifuge at 8000 r / min for 15 min to obtain clear oil; (6) Alkaline extraction and acid precipitation: Divide the enzymatic hydrolysate into enzymatic hydrolysate A and enzymatic hydrolysate B with a volume ratio of 1:1. Adjust the pH of enzymatic hydrolysate A to 9.0 - 9.5 with 2 mol / L sodium hydroxide solution, perform alkaline extraction for 20 min, then adjust the pH to 4.0 - 5.0 with 2 mol / L hydrochloric acid solution, perform acid precipitation for 15 min, and then centrifuge at 4000 r / min for 30 min to obtain protein and precipitate; (7) Secondary enzymatic hydrolysis: Mix the precipitate with enzymatic hydrolysate B, add amylase and protease with a mass ratio of 1:1, and the total addition amount is 0.5% of the mass of enzymatic hydrolysate B. Perform secondary enzymatic hydrolysis at 55 °C for 30 min to obtain a secondary enzymatic hydrolysis product; (8) Temperature-controlled heating: After mixing the secondary enzymatic hydrolysis product with refined oil, perform temperature-controlled heating at 150 °C for 6 min to obtain peanut oil with a rich flavor.

[0025] Example 4 A method for improving the flavor of peanut oil prepared by the aqueous enzymatic method, comprising the following steps: (1) Raw material screening: Remove impurities and mildewed peanuts from the peanut kernels to obtain the screened peanut kernels; (2) Crushing: Crush the screened peanut kernels with a high-speed crusher for 30 s and pass through a 400-mesh sieve to obtain peanut powder; (3) Ultrasonic pretreatment: Mix the peanut powder and water at a mass ratio of 1:5, stir at room temperature for 50 min under ultrasonic assistance to obtain a mixed solution; (4) Enzymatic hydrolysis: Add a mixed enzyme to the mixed solution, the addition amount of the mixed enzyme is 2% of the mass of the mixed solution, and the mixed enzyme is a mixture of pectinase, cellulase, and hemicellulase with a mass ratio of 4:2:1. React at 50 °C for 3 h, then place it in boiling water to inactivate the enzyme for 15 min, cool to room temperature, and then centrifuge at 5000 r / min for 20 min to obtain a high-oil-content emulsified oil layer and an enzymatic hydrolysate; (5) Microwave demulsification of the emulsified oil layer: Treat the high-oil-content emulsified oil layer under 600 W microwave conditions for 60 s, and then centrifuge at 6000 r / min for 20 min to obtain refined oil; (6) Alkaline extraction and acid precipitation: Divide the enzymatic hydrolysate into enzymatic hydrolysate A and enzymatic hydrolysate B with a volume ratio of 1:1. Adjust the pH of enzymatic hydrolysate A to 9.0 - 9.5 with 2 mol / L sodium hydroxide solution, perform alkaline extraction for 35 min, then adjust the pH to 4.0 - 5.0 with 2 mol / L hydrochloric acid solution, perform acid precipitation for 12 min, and then centrifuge at 6000 r / min for 20 min to obtain protein and precipitate; (7) Secondary enzymatic hydrolysis: Mix the precipitate with enzymatic hydrolysis solution B, add amylase and protease, with a mass ratio of amylase to protease of 1:1, and the total addition amount is 0.5% of the mass of enzymatic hydrolysis solution B. Conduct secondary enzymatic hydrolysis at 55°C for 30 min to obtain a secondary enzymatic hydrolysis product; (8) Temperature-controlled heating: After mixing the secondary enzymatic hydrolysis product with refined oil, conduct temperature-controlled heating at 155°C for 5 min to obtain peanut oil with a rich flavor.

[0026] Example 5 A method for improving the flavor of peanut oil prepared by the aqueous enzymatic method, comprising the following steps: (1) Raw material screening: Remove impurities and moldy peanuts from the peanut kernels to obtain screened peanut kernels; (2) Crushing: Crush the screened peanut kernels with a high-speed crusher for 30 s, and pass through a 400-mesh sieve to obtain peanut powder; (3) Ultrasonic pretreatment: Mix the peanut powder and water at a mass ratio of 1:5, and stir at room temperature for 40 min under ultrasonic assistance to obtain a mixed solution; (4) Enzymatic hydrolysis: Add a mixed enzyme to the mixed solution, with the addition amount of the mixed enzyme being 4% of the mass of the mixed solution. The mixed enzyme is a mixture of pectinase, cellulase, and hemicellulase with a mass ratio of 4:2:1. React at 50°C for 3 h, then place it in boiling water to inactivate the enzyme for 10 min, cool to room temperature, and then centrifuge at 5000 r / min for 20 min to obtain a high-oil-content emulsified oil layer and an enzymatic hydrolysis solution; (5) Microwave demulsification of the emulsified oil layer: Treat the high-oil-content emulsified oil layer under 600W microwave conditions for 60 s, and then centrifuge at 6000 r / min for 25 min to obtain refined oil; (6) Alkaline extraction and acid precipitation: Divide the enzymatic hydrolysis solution into enzymatic hydrolysis solution A and enzymatic hydrolysis solution B, with a volume ratio of enzymatic hydrolysis solution A to enzymatic hydrolysis solution B of 1:1. Adjust the pH of enzymatic hydrolysis solution A to 9.0 - 9.5 with a 2mol / L sodium hydroxide solution, conduct alkaline extraction for 35 min, then adjust the pH to 4.0 - 5.0 with a 2mol / L hydrochloric acid solution, conduct acid precipitation for 10 min, and then centrifuge at 6000 r / min for 20 min to obtain protein and a precipitate; (7) Secondary enzymatic hydrolysis: Mix the precipitate with enzymatic hydrolysis solution B, add amylase and protease, with a mass ratio of amylase to protease of 1:1, and the total addition amount is 0.5% of the mass of enzymatic hydrolysis solution B. Conduct secondary enzymatic hydrolysis at 55°C for 30 min to obtain a secondary enzymatic hydrolysis product; (8) Temperature-controlled heating: After mixing the secondary enzymatic hydrolysis product with refined oil, conduct temperature-controlled heating at 160°C for 5 min to obtain peanut oil with a rich flavor.

[0027] Comparative Example 1 A method for preparing peanut oil by the aqueous enzymatic method, comprising the following steps: (1)Raw material screening: Remove impurities and mildewed peanuts from the peanut kernels to obtain the screened peanut kernels. (2)Crushing: Crush the screened peanut kernels with a high-speed crusher for 30 s and pass through a 400-mesh sieve to obtain peanut powder. (3)Ultrasonic pretreatment: Mix peanut powder and water at a mass ratio of 1:5, and stir at room temperature for 40 min under ultrasonic assistance to obtain a mixed solution. (4)Enzymatic hydrolysis: Add a mixed enzyme to the mixed solution. The addition amount of the mixed enzyme is 4% of the mass of the mixed solution. The mixed enzyme is a mixture of pectinase, cellulase, and hemicellulase with a mass ratio of 4:2:1. React at 50 °C for 3 h, then place the mixed solution in boiling water to inactivate the enzyme for 10 min, cool to room temperature, and then centrifuge at 5000 r / min for 20 min to obtain an emulsified oil layer with a high oil content and an enzymatic hydrolysate; the addition amount of the enzyme is 4% of the mass of the mixed solution. (5)Microwave demulsification of the emulsified oil layer: Treat the emulsified oil layer with a high oil content under 600 W microwave conditions for 60 s, and then centrifuge at 6000 r / min for 25 min to obtain clear oil, which is peanut oil. (6)Alkali extraction and acid precipitation: Adjust the pH of the enzymatic hydrolysate to 9.0 - 9.5 with a 2 mol / L sodium hydroxide solution, perform alkali extraction for 35 min, then adjust the pH to 4.0 - 5.0 with a 2 mol / L hydrochloric acid solution, perform acid precipitation for 10 min, and then centrifuge at 6000 r / min for 20 min to obtain protein.

[0028] Experimental Example 1 Detect the content of flavor substances in the peanut oil of Examples 1 - 5. The detection results are listed in Table 1.

[0029] Table 1. Content of flavor substances in peanut oil As can be seen from Table 1, the content of flavor substances in the peanut oil of Example 1 is 58.52 mg / kg, that in Example 2 is 60.94 mg / kg, that in Example 3 is 61.46 mg / kg, that in Example 4 is 62.70 mg / kg, and that in Example 5 is 63.97 mg / kg. It can be seen that the content of flavor substances in the peanut oil of Examples 1 - 5 is higher than 58.52 mg / kg. This shows that the method of the present invention, through technical means such as secondary enzymatic hydrolysis and temperature-controlled heating, utilizes Maillard reaction products to significantly increase the flavor of peanut oil, realizes the retention of intact protein in peanuts while extracting peanut oil, and effectively improves the content of flavor substances in peanut oil, which is beneficial to the comprehensive utilization of products.

[0030] Experimental Example 2 Detect the flavor substance content in the peanut oil of Example 5 and Comparative Example 1, and the detection results are listed in Table 2.

[0031] Table 2. Flavor Substance Content in Peanut Oil As can be seen from Table 2, the flavor substance content in the peanut oil of Example 5 is 63.97 mg / kg; Comparative Example 1 uses the general method for preparing peanut oil in the prior art, and the flavor substance content in the obtained peanut oil is 50.23 mg / kg; it can be seen that the flavor substance content in the peanut oil obtained by the method of the present invention is quite different from that obtained by the prior art, indicating that the method of the present invention can significantly increase the flavor substance content in peanut oil.

[0032] Experimental Example 3 Referring to the process method of Example 5, explore the influence of the temperature of temperature-controlled heating on the flavor substance content in peanut oil. The temperatures of temperature-controlled heating are set at 135, 140, 145, 150, 155, 160, and 165 °C respectively, and the flavor substance content in peanut oil is detected. The detection results are listed in Table 3.

[0033] Table 3. Flavor Substance Content in Peanut Oil As can be seen from Table 3, when the temperature of temperature-controlled heating is 135 - 160 °C, the flavor substance content in peanut oil increases with the increase of temperature. However, when the temperature of temperature-controlled heating is 165 °C, the flavor substance content decreases because the temperature is too high at this time, and the caramelization reaction dominates, which will destroy the flavor substances generated by the Maillard reaction, and the too high temperature will also increase the production cost. Therefore, the present invention selects the temperature of temperature-controlled heating to be 140 - 160 °C, at which time the flavor substance content in peanut oil is high.

Claims

1. A method for improving the flavor of peanut oil prepared by the aqueous enzymatic method, characterized in that: It includes the following steps: (1) Raw material screening: Remove impurities and mildewed peanuts from the peanut kernels to obtain the screened peanut kernels; (2) Crushing: Crush the screened peanut kernels with a high-speed crusher for 30 s, and then sieve to obtain peanut powder; (3) Ultrasonic pretreatment: Mix the peanut powder with water, and stir at room temperature for 30 - 60 min under ultrasonic assistance to obtain a mixed solution; (4) Enzymolysis: Add a mixed enzyme to the mixed solution, react at 40 - 60 °C for 2 - 4 h, then place it in boiling water to inactivate the enzyme for 10 - 15 min, cool to room temperature, and then centrifuge for 15 - 25 min to obtain an emulsified oil layer with a high oil content and an enzymolysis solution; (5) Microwave demulsification of the emulsified oil layer: Perform microwave treatment on the emulsified oil layer with a high oil content, and then centrifuge to obtain clear oil; (6) Alkaline extraction and acid precipitation: Divide the enzymolysis solution into enzymolysis solution A and enzymolysis solution B. Adjust the pH of enzymolysis solution A to 9.0 - 9.5 with a 2 mol / L sodium hydroxide solution, perform alkaline extraction for 20 - 50 min, then adjust the pH to 4.0 - 5.0 with a 2 mol / L hydrochloric acid solution, perform acid precipitation for 10 - 15 min, and then centrifuge at 4000 - 8000 r / min for 15 - 30 min to obtain protein and precipitate; (7) Secondary enzymolysis: Mix the precipitate with enzymolysis solution B, add amylase and protease for secondary enzymolysis to obtain a secondary enzymolysis product; (8) Temperature-controlled heating: Mix the secondary enzymolysis product with the clear oil and perform temperature-controlled heating to obtain peanut oil with a rich flavor.

2. The method for improving the flavor of peanut oil prepared by the aqueous enzymatic method according to claim 1, wherein: In step (3), the mass ratio of the peanut powder to water is 1:

5.

3. The method for improving the flavor of peanut oil prepared by the aqueous enzymatic method according to claim 1, wherein: In step (4), the addition amount of the mixed enzyme is 2 - 5% of the mass of the mixed solution.

4. The method for improving the flavor of peanut oil prepared by the aqueous enzymatic method according to claim 1, characterized in that: In step (5), the power of the microwave treatment is 500 - 800 W, and the time of the microwave treatment is 40 - 80 s; the rotation speed of the centrifuge is 4000 - 8000 r / min, and the time of the centrifuge is 15 - 30 min.

5. The method for improving the flavor of peanut oil prepared by the aqueous enzymatic method according to claim 1, characterized in that: In step (6), the volume ratio of enzymolysis solution A to enzymolysis solution B is 1:

1.

6. The method for improving the flavor of peanut oil prepared by the aqueous enzyme method according to claim 1, characterized in that: In step (7), the temperature of the secondary enzymolysis is 50 - 60 °C, and the time is 30 min.

7. The method for improving the flavor of peanut oil prepared by the aqueous enzymatic method according to claim 1, wherein: In step (7), the total addition amount of the amylase and protease is 0.5% of the mass of enzymolysis solution B.

8. The method for improving the flavor of peanut oil prepared by the aqueous enzymatic method according to claim 1, wherein: In step (8), the temperature of the temperature-controlled heating is 140 - 160 °C, and the time of the temperature-controlled heating is 4 - 6 min.

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