A method for extracting a raw flavor high oleic peanut oil

Abstract

The present application relates to the technical field of peanut oil extraction, and particularly relates to a method for extracting peanut oil with high oleic acid and original flavor, comprising the following steps: S1, screening: screening the peanut raw material subjected to peeling treatment by using a vibrating screening device to screen out impurities in the peanut raw material, so as to obtain peanut raw material; S2, pretreatment: sequentially subjecting the screened peanut raw material to three-stage low-temperature gradient drying, and using infrared auxiliary dehydration, and controlling the total water content at 3%-4%; the method for extracting peanut oil with high oleic acid and original flavor, by adding starch-chitosan composite liquid, the starch-chitosan composite liquid is compounded by natural ingredients and strengthened by nano structure, realizing multiple functions of antioxidation, bacteriostasis and physical barrier, while retaining the original flavor of peanut oil, significantly improving the stability of oleic acid, and having clear technical effect and industrialization potential.

Description

Technical Field

[0001] This invention relates to the field of peanut oil extraction technology, specifically to a method for extracting high-oleic peanut oil with original aroma and flavor. Background Technology

[0002] Peanut oil is an edible oil with a clear color, rich aroma, and easy digestibility. It contains about 80% unsaturated fatty acids, including about 41% oleic acid and about 38% linoleic acid. These fatty acids can help lower cholesterol and triglycerides in the blood, reducing the risk of cardiovascular disease. In addition, unsaturated fatty acids can enhance cell membrane permeability, which helps with the absorption of nutrients and the excretion of waste, thus benefiting health.

[0003] A patent with publication number CN118480393A discloses a method for preparing high-oleic peanut oil, relating to the field of peanut oil preparation technology. This method includes the following steps: S1: Raw material screening and processing, where peanut raw materials are screened using a vibrating sieve to remove impurities, and then the screened peanuts are placed in a shelling machine for shelling and peeling to obtain peanut raw materials; S2: Raw material drying and crushing, where the peanut raw materials obtained in step S1 are placed in a dryer for low-temperature drying, and then the low-temperature dried peanut raw materials are crushed using a crusher. By adding selenium-rich camellia root powder to the crushed peanut raw materials, the oleic acid content in the peanut oil is increased, which also enhances the flavor and nutritional value of the peanut oil. Furthermore, the increased oleic acid content also extends the shelf life of the peanut oil after opening.

[0004] However, in the aforementioned patent documents, although using selenium-rich camellia root powder as an antioxidant increases the oleic acid content in the subsequently prepared peanut oil and enhances its flavor, its natural components may carry special odors (such as grassy or earthy smells), which may react with the original flavor substances during peanut oil processing, leading to mixed or lost aromas. In view of this, we propose a method for extracting high-oleic acid peanut oil with original aroma. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings mentioned in the background section and provide a method for extracting high-oleic peanut oil with an original aroma.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0007] A method for extracting high-oleic peanut oil with original aroma and flavor includes the following steps:

[0008] S1. Screening: The peeled peanut raw materials are screened using a vibrating screen to remove impurities and obtain peanut raw materials.

[0009] S2. Pretreatment: The screened peanut raw materials are subjected to three-stage low-temperature gradient drying and infrared-assisted dehydration is used to control the total moisture content at 3%-4%.

[0010] S3. Coating treatment: The dried peanut raw material is immersed in a coating solution composed of starch-chitosan composite liquid, and negative pressure adsorption technology is used to make the coating solution evenly cover the surface of the peanut raw material. After drying, an antioxidant barrier is formed.

[0011] S4. Crushing: The coated peanut raw material is crushed and broken down using a crusher to crush the peanut particles into peanut crumbs;

[0012] S5. Low-temperature pressing: Peanut crushes are pulse-pressed under pressure of 10-50MPa and temperature ≤45℃. After pressing, the oil is purified by low-temperature filtration and molecular distillation to obtain high-oleic peanut oil.

[0013] Preferably, the peanut raw material is selected from high oleic acid peanuts, and the oleic acid content is ≥78%.

[0014] Preferably, in step S2, the temperatures of the low-temperature gradient drying are 40°C, 50°C and 60°C, and the drying time for each segment is 20-30 minutes.

[0015] Preferably, in step S2, the infrared wavelength is 800-1200nm and the power density is 0.5-1.0W / cm². 2 The ozone sterilization concentration is 0.5-1.0 mg / L, and the treatment time is 10-15 minutes.

[0016] Preferably, the mass fractions of each component in the starch-chitosan composite liquid raw material are as follows:

[0017]

[0018] Preferably, the preparation steps of the starch-chitosan composite solution are as follows:

[0019] Step 1: Disperse corn starch in deionized water and stir for 30 minutes. Then heat to 85-90℃ and continue stirring for 30 minutes until completely gelatinized to form a transparent colloid. Then cool to 50℃, add dispersant, and homogenize to obtain starch gelatinized liquid.

[0020] Step 2: Dissolve chitosan powder in pH adjuster, stir magnetically for 2 hours, adjust pH to 5.0-5.5, let stand to remove bubbles and set aside to obtain chitosan solution;

[0021] Step 3: Immerse the hydroxyapatite nanowires in an ethanol solution of silane coupling agent, sonicate for 30 minutes, then centrifuge and vacuum dry at 60°C to obtain modified hydroxyapatite nanowires.

[0022] Step 4: Mix the starch gelatinized liquid, chitosan solution and modified hydroxyapatite nanowires in proportion, add vitamin E, stir magnetically for 1 hour, and homogenize under high pressure to form a uniformly dispersed starch-chitosan composite liquid.

[0023] Preferably, the pH adjuster is citric acid or malic acid.

[0024] Preferably, the dispersant is polyoxyethylene sorbitan monooleate or methylcellulose.

[0025] Preferably, the pressure fluctuation frequency of the pulse pressing is 0.5-1.0Hz, the pressing time is 20-30 minutes, and the residual oil content of the cake after pressing is ≤10%.

[0026] Preferably, the low-temperature filtration uses a ceramic membrane with a pore size of 0.1-0.5 μm, the molecular distillation temperature is 80-90℃, and the vacuum degree is ≤50Pa.

[0027] Compared with the prior art, the beneficial effects of the present invention are:

[0028] 1. This invention uses a three-stage low-temperature drying process to gradually dehydrate and avoid thermal decomposition of aroma substances caused by sudden temperature rise. Infrared radiation is used to selectively stimulate moisture vibration, accelerating dehydration without damaging macromolecular flavor substances.

[0029] 2. This invention utilizes a starch-chitosan composite solution to create a continuous colloidal network from gelatinized starch. Chitosan is embedded into the network via hydrogen bonds, increasing the film density and blocking oxygen permeation. Modified hydroxyapatite nanowires serve as a "skeleton" to extend the oxygen diffusion path, and a silane coupling agent enhances the interfacial bonding strength with the matrix, preventing pressing cracks. Simultaneously, vitamin E is embedded in the film layer and gradually migrates to the oil phase during the oil release stage, continuously capturing free radicals and blocking the oxidation chain reaction. This starch-chitosan composite solution, through the combination of natural components and nanostructure reinforcement, achieves multiple functions including anti-oxidation, antibacterial, and physical barrier properties. While preserving the original aroma of peanut oil, it significantly improves the stability of oleic acid. The technical effects are clear and it has industrialization potential. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] The present invention will describe the above technical solution in detail through the following embodiments:

[0032] Example 1

[0033] A method for extracting high-oleic peanut oil with original aroma includes the following steps: First, peeled high-oleic peanuts are screened using a vibrating sieve to remove impurities from the peanuts, ensuring the oleic acid content is ≥78%. Then, the screened peanut raw material is subjected to a three-stage low-temperature gradient drying process at temperatures of 40℃, 50℃, and 60℃, with each stage lasting 20 minutes. Infrared assisted dehydration is used to control the total moisture content at 3%, with an infrared wavelength of 800nm ​​and a power density of 0.5W / cm³. 2 The ozone sterilization concentration was 0.5 mg / L, and the treatment time was 10 minutes. Then, the dried peanut raw material was immersed in a coating solution composed of starch-chitosan composite liquid, and negative pressure adsorption technology was used to make the coating solution evenly cover the surface of the peanut raw material, forming an antioxidant barrier after drying. The coated peanut raw material was then crushed by a pulverizer to break the peanut particles into peanut crumbs. Finally, the peanut crumbs were pulse-pressed under the conditions of pressure 20 MPa and temperature ≤45℃, with a pressure fluctuation frequency of 1.0 Hz and a pressing time of 20 minutes. The residual oil rate of the cake after pressing was ≤10%. The pressed oil was purified by low-temperature filtration and molecular distillation. The low-temperature filtration used a ceramic membrane with a pore size of 0.5 μm, and the molecular distillation temperature was 90℃ with a vacuum degree ≤50 Pa to obtain high oleic acid peanut oil.

[0034] The specific mass fractions of each component in the starch-chitosan composite liquid raw material are as follows:

[0035]

[0036] The specific steps for preparing the starch-chitosan composite solution are as follows: First, corn starch is dispersed in deionized water with a solid content of 15%, stirred for 30 minutes, then heated to 90℃ and stirred continuously for 30 minutes until completely gelatinized to form a transparent colloid. The temperature is then lowered to 50℃, polyoxyethylene sorbitan monooleate is added, and the mixture is homogenized under a pressure of 20 MPa for 3 cycles to obtain a starch gelatinized solution. Then, chitosan powder is dissolved in a pH adjuster, magnetically stirred for 2 hours, and the pH is adjusted to 5.5. After standing to remove bubbles, a chitosan solution was obtained. Then, hydroxyapatite nanowires were immersed in a 3% silane coupling agent (KH-550) ethanol solution, sonicated for 30 minutes, centrifuged, and vacuum dried at 60°C to obtain modified hydroxyapatite nanowires. Finally, starch gelatinized liquid, chitosan solution, and modified hydroxyapatite nanowires were mixed in proportion, vitamin E was added, and the mixture was magnetically stirred for 1 hour. High-pressure homogenization was carried out at 50 MPa and cyclicated twice to form a uniformly dispersed starch-chitosan composite liquid.

[0037] In this embodiment, chitosan powder was purchased from Shandong Guante Bioengineering Co., Ltd.; hydroxyapatite nanowires were purchased from Shaanxi Yiming Biotechnology Co., Ltd.; corn starch was purchased from Aladdin Biochemical Technology Co., Ltd.; and vitamin E was purchased from Anhui Zhonghong Bioengineering Co., Ltd.

[0038] It should be noted that this embodiment uses a three-stage low-temperature drying process (40℃→50℃→60℃) to gradually dehydrate the oil and avoid thermal decomposition of aroma substances caused by sudden temperature increases. At the same time, infrared radiation is used to selectively stimulate water vibration, accelerating dehydration without damaging macromolecular flavor substances (such as pyrazine compounds with melting points of 80-100℃, which are stable at low temperatures). Ozone is used instead of high-temperature sterilization. Ozone inactivates microorganisms at room temperature, avoiding excessive consumption of free amino acids (aroma precursors) caused by Maillard reactions in traditional high-temperature sterilization. This results in a retention rate of ≥90% for key volatile substances in high-oleic peanut oil (such as 2,5-dimethylpyrazine and furanone).

[0039] It should be explained that in this embodiment, a starch-chitosan composite liquid is used. By gelatinizing starch to form a continuous colloidal network, chitosan is embedded in the network through hydrogen bonds, which increases the film density and porosity to ≤5%, blocking oxygen permeation and reducing oxygen permeability by 60%. At the same time, modified hydroxyapatite nanowires serve as a "skeleton" to extend the oxygen diffusion path, and the interfacial bonding strength with the matrix is ​​improved by silane coupling agents to prevent pressing cracking. Furthermore, vitamin E is embedded in the film layer and gradually migrates to the oil phase during the oil release stage, continuously capturing free radicals and blocking the oxidation chain reaction. This can improve the storage time of peanut oil after opening, making it more convenient for users to consume.

[0040] Example 2

[0041] The only difference between this embodiment and Embodiment 1 is that the specific mass fractions of each component of the starch-chitosan composite liquid raw material in this embodiment are: 80 parts corn starch, 2 parts chitosan powder, 5 parts hydroxyapatite nanowires, 0.3 parts vitamin E, 0.2 parts citric acid, and 0.2 parts polyoxyethylene sorbitan monooleate. All other conditions are the same.

[0042] Example 3

[0043] The only difference between this embodiment and Embodiment 1 is that the specific mass fractions of each component of the starch-chitosan composite liquid raw material in this embodiment are: 80 parts corn starch, 4 parts chitosan powder, 8 parts hydroxyapatite nanowires, 0.4 parts vitamin E, 0.2 parts citric acid, and 0.2 parts polyoxyethylene sorbitan monooleate. All other conditions are the same.

[0044] Example 4

[0045] The only difference between this embodiment and Embodiment 1 is that the specific mass fractions of each component of the starch-chitosan composite liquid raw material in this embodiment are: 80 parts corn starch, 5 parts chitosan powder, 10 parts hydroxyapatite nanowires, 0.6 parts vitamin E, 0.2 parts citric acid, and 0.2 parts polyoxyethylene sorbitan monooleate. All other conditions are the same.

[0046] Comparative Example 1

[0047] The only difference between this comparative example and Example 1 is that the starch-chitosan composite solution used in this comparative example is a single starch composite solution, while all other conditions are the same.

[0048] Comparative Example 2

[0049] The only difference between this comparative example and Example 1 is that chitosan powder is not added to the starch-chitosan composite solution in this comparative example, while all other conditions are the same.

[0050] Comparative Example 3

[0051] The only difference between this comparative example and Example 1 is that the starch-chitosan composite solution in this comparative example does not contain hydroxyapatite nanowires, while all other conditions are the same.

[0052] Comparative Example 4

[0053] The only difference between this comparative example and Example 1 is that vitamin E is not added to the starch-chitosan composite solution in this comparative example, while all other conditions are the same.

[0054] Based on Examples 1-4 and Comparative Examples 1-4 above, high-oleic peanut oil samples were prepared and their properties were tested. The specific performance tests of the high-oleic peanut oil are as follows:

[0055] Oleic acid content detection: The high oleic acid peanut oil samples prepared in Examples 1-4 and Comparative Examples 1-4 were used respectively. The oleic acid content in the peanut oil was detected according to GB5009.168-2016. The data were recorded as oleic acid relative to the total fatty acid content.

[0056] Oil yield test: High oleic acid peanut oil samples prepared in Examples 1-4 and Comparative Examples 1-4 were used respectively. With a peanut raw material weight of 100 kg, the oil yield was calculated as follows: Oil yield = (mass of peanut oil) / (mass of peanuts) × 100%;

[0057] Acid value test: The high oleic acid peanut oil samples prepared in Examples 1-4 and Comparative Examples 1-4 were tested for acid value (calculated as KOH) in accordance with GB / T5530-2005 Determination of Acid Value and Acidity of Animal and Vegetable Oils, and the data were recorded.

[0058] Oxidative stability test: High oleic peanut oil samples prepared in Examples 1-4 and Comparative Examples 1-4 were used respectively. The peroxide value (PV) and acid value (AV) were determined according to GB 5009.227-2016. Accelerated oxidation test (stored at 60℃ for 30 days) was conducted, and the thiobarbituric acid value (TBARS) was determined and the data were recorded.

[0059] The specific data is shown in Table 1 below:

[0060]

[0061] Table 1

[0062] As shown in Table 1 above, when the amounts of chitosan powder, hydroxyapatite nanowires, and vitamin E in Example 2 decreased, the oleic acid, oil yield, and acid value were not as good as in Example 1. Examples 3 and 4 show that as the amounts of chitosan powder, hydroxyapatite nanowires, and vitamin E gradually increased, the effects on oleic acid, oil yield, acid value, and peroxide value gradually decreased. The data indicates that higher amounts of chitosan powder, hydroxyapatite nanowires, and vitamin E resulted in a decrease in the effects on oleic acid, oil yield, acid value, and peroxide value. However, adding more chitosan powder, hydroxyapatite nanowires, and vitamin E resulted in abnormal data, without bringing about a higher effect. Therefore, as shown in Example 1, when the amounts of chitosan powder (3 parts), hydroxyapatite nanowires (7 parts), and vitamin E (0.4 parts) were present, the high-oleic peanut oil exhibited the best effects on oleic acid, oil yield, acid value, and peroxide value.

[0063] Data from Example 1 and Comparative Examples 2, 3, and 4 show that, in the preparation of the starch-chitosan composite liquid in Comparative Example 2, no chitosan powder was added. Compared to Example 1, the oleic acid content, oil yield, and acid value of the high-oleic peanut oil prepared in Comparative Example 2 were all lower than those in Example 1. Furthermore, the peroxide value of the high-oleic peanut oil prepared in Comparative Example 2 was higher than that in Example 1. Moreover, the peroxide values ​​of the high-oleic peanut oil prepared in Comparative Examples 3 and 4 were higher than those in Comparative Example 2. This indicates that the effect of chitosan is greater than that of hydroxyapatite nanowires and vitamin E. By gelatinizing starch to form a continuous colloidal network, chitosan is embedded in the network through hydrogen bonds, increasing the film density, reducing the porosity to ≤5%, blocking oxygen permeation, and reducing oxygen permeability by 60%. This achieves multiple functions of anti-oxidation and physical barrier, significantly improving the stability of oleic acid while preserving the original aroma of peanut oil.

[0064] Comparative Example 1 data shows that the existing single starch composite solution is not effective. The data of Comparative Example 1 differs significantly from those of Examples 1-4, indicating that although using a single starch composite solution can achieve certain effects, it is still far inferior to the starch-chitosan composite solution in Examples 1-4. This shows that gelatinized starch can form a continuous colloidal network, and chitosan is embedded in the network through hydrogen bonds, which increases the film density and blocks oxygen permeation. Furthermore, modified hydroxyapatite nanowires serve as a "skeleton" to extend the oxygen diffusion path and enhance the interfacial bonding strength with the matrix through silane coupling agents, preventing pressing cracks. At the same time, vitamin E is embedded in the film layer and gradually migrates to the oil phase during the oil release stage, continuously capturing free radicals and blocking the oxidation chain reaction. This starch-chitosan composite solution is enhanced by the combination of natural ingredients and nanostructure.

[0065] Based on the data in the table above, Example 1 is preferred.

[0066] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A method for extracting high-oleic peanut oil with original aroma and flavor, characterized in that: Includes the following steps: S1. Screening: The peeled peanut raw materials are screened using a vibrating screen to remove impurities and obtain peanut raw materials. S2. Pretreatment: The screened peanut raw materials are subjected to three-stage low-temperature gradient drying and infrared-assisted dehydration, with the total moisture content controlled at 3%-4%. S3. Coating treatment: The dried peanut raw material is immersed in a coating solution composed of starch-chitosan composite liquid, and negative pressure adsorption technology is used to make the coating solution evenly cover the surface of the peanut raw material. After drying, an antioxidant barrier is formed. S4. Crushing: The coated peanut raw material is crushed and broken down using a crusher to crush the peanut particles into peanut crumbs; S5. Low-temperature pressing: Peanut crushes are pulse-pressed under pressure of 10-50 MPa and temperature ≤45℃. After pressing, the oil is purified by low-temperature filtration and molecular distillation to obtain high oleic acid peanut oil. In step S2, the temperatures of the low-temperature gradient drying are 40°C, 50°C and 60°C, and the drying time for each segment is 20-30 minutes. The specific steps for preparing the starch-chitosan composite solution are as follows: Step 1: Disperse corn starch in deionized water and stir for 30 minutes. Then heat to 85-90℃ and continue stirring for 30 minutes until completely gelatinized to form a transparent colloid. Then cool to 50℃, add dispersant, and homogenize to obtain starch gelatinized liquid. Step 2: Dissolve chitosan powder in pH adjuster, stir magnetically for 2 hours, adjust pH to 5.0-5.5, let stand to remove bubbles and set aside to obtain chitosan solution; Step 3: Immerse the hydroxyapatite nanowires in an ethanol solution of silane coupling agent, sonicate for 30 minutes, then centrifuge and vacuum dry at 60°C to obtain modified hydroxyapatite nanowires. Step 4: Mix the starch gelatinized liquid, chitosan solution and modified hydroxyapatite nanowires in proportion, add vitamin E, stir magnetically for 1 hour, and homogenize under high pressure to form a uniformly dispersed starch-chitosan composite liquid.

2. The method for extracting high-oleic peanut oil with original aroma as described in claim 1, characterized in that: The peanut raw material is selected from high oleic acid peanuts, and the oleic acid content is ≥78%.

3. The method for extracting high-oleic peanut oil with original aroma as described in claim 1, characterized in that: In step S2, the infrared wavelength is 800-1200 nm, the power density is 0.5-1.0 W / cm², the ozone sterilization concentration is 0.5-1.0 mg / L, and the treatment time is 10-15 minutes.

4. The method for extracting high-oleic peanut oil with original aroma as described in claim 1, characterized in that: The specific mass fractions of each component in the starch-chitosan composite liquid raw material are as follows: Corn starch: 80-90 parts; Chitosan powder: 2-5 parts; Hydroxyapatite nanowires: 5-10 parts; Vitamin E: 0.3-0.6 parts; pH adjuster: 0.1-0.3 parts; Dispersant: 0.1-0.3 parts.

5. The method for extracting high-oleic peanut oil with original aroma as described in claim 4, characterized in that: The pH adjuster is selected from citric acid or malic acid.

6. The method for extracting high-oleic peanut oil with original aroma as described in claim 4, characterized in that: The dispersant is selected from polyoxyethylene sorbitan monooleate or methylcellulose.

7. The method for extracting high-oleic peanut oil with original aroma as described in claim 1, characterized in that: The pulse pressing has a pressure fluctuation frequency of 0.5-1.0 Hz, a pressing time of 20-30 minutes, and a residual oil content of ≤10% in the cake after pressing.

8. The method for extracting high-oleic peanut oil with original aroma as described in claim 1, characterized in that: The low-temperature filtration uses a ceramic membrane with a pore size of 0.1-0.5μm, a molecular distillation temperature of 80-90℃, and a vacuum degree of ≤50 Pa.

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