Method for extracting high-oleic-acid peanut oil with original flavor

Abstract

The invention relates to the technical field of peanut oil extraction, in particular to a method for extracting original-flavor high-oleic-acid peanut oil, which comprises the following steps: S1, screening: screening peeled peanut raw materials by using vibrating screening equipment, and screening out impurities in the peanut raw materials to obtain the peanut raw materials; s2, pretreatment: sequentially performing three-stage low-temperature gradient drying on the screened peanut raw materials, performing assisted dehydration by adopting infrared rays, and controlling the total moisture content to be 3-4%; according to the method for extracting the high-oleic-acid peanut oil with the original flavor, the starch-chitosan composite liquid is added, so that the starch-chitosan composite liquid achieves multiple functions of oxidation resistance, bacteriostasis and physical barrier through natural component compounding and nanostructure strengthening, the original flavor of the peanut oil is reserved, meanwhile, the stability of oleic acid is remarkably improved, and the peanut oil has the original flavor. The technical effect is clear, and industrialization potential is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of peanut oil extraction, and particularly relates to a method for extracting high-oleic acid peanut oil with original flavor. Background Art

[0002] Peanut oil is a kind of edible oil, with clear color, strong fragrance, easy to digest. And about 80% of the unsaturated fatty acids in peanut oil, among which oleic acid is about 41% and linoleic acid is about 38%. It can help reduce cholesterol and triglycerides in the blood and reduce the risk of cardiovascular diseases. In addition, unsaturated fatty acids can also enhance the permeability of cell membranes, contribute to the absorption of nutrients and the excretion of waste, and be beneficial to physical health.

[0003] The patent with the publication number of CN118480393A discloses a method for preparing high-oleic acid peanut oil, which relates to the technical field of peanut oil preparation. The method for preparing high-oleic acid peanut oil includes the following preparation steps: S1: Screening and processing of raw materials. The peanut raw materials are screened by a vibrating screening device to remove impurities in the peanut raw materials, and then the peanuts after screening are put into a hulling machine for hulling and peeling to obtain peanut raw materials; S2: Drying and pulverizing of raw materials. The peanut raw materials obtained in step S1 are put into a dryer for low-temperature drying, and then the peanut raw materials after low-temperature drying are pulverized and crushed by a pulverizer. By adding selenium-rich camellia root powder to the peanut crushed raw materials, while increasing the oleic acid content in the peanut oil, it can also increase the flavor of the peanut oil, increase the nutritional value of the peanut oil, and by increasing the oleic acid content in the peanut oil, it can also improve the storage time of the peanut oil after opening.

[0004] However, in the above patent document, by using selenium-rich camellia root powder as an antioxidant, although it increases the oleic acid content in the subsequent preparation of peanut oil and can also increase the flavor of the peanut oil, its natural components may carry special odors (such as grassy smell or earthy smell), which react with the original flavor substances during the peanut oil processing, resulting in the mixture or loss of the fragrance. In view of this, we propose a method for extracting high-oleic acid peanut oil with original flavor. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies mentioned in the above background art and provide a method for extracting high-oleic acid peanut oil with original flavor.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

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

[0008] S1. Screening: The peeled peanut raw materials are screened using a vibrating screening device to remove impurities in the peanut raw materials, obtaining peanut raw materials;

[0009] S2. Pretreatment: The screened peanut raw materials are dried in a three-stage low-temperature gradient successively and infrared-assisted dehydration is adopted, with the total moisture content controlled at 3%-4%;

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

[0011] S4. Crushing: The coated peanut raw materials are crushed and broken using a crusher to crush the peanut granules into peanut crumbs;

[0012] S5. Low-temperature pressing: The peanut crumbs are subjected to pulsed pressing under the conditions of a pressure of 10-50 MPa and a temperature ≤ 45°C. After pressing, the oil is purified by low-temperature filtration and molecular distillation to obtain high-oleic acid peanut oil.

[0013] Preferably, the peanut raw materials are 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 respectively, and the drying time for each stage is 20-30 minutes.

[0015] Preferably, in step S2, the infrared wavelength is 800-1200 nm, the power density is 0.5-1.0 W / cm 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 the components of the starch-chitosan composite solution raw materials are specifically:

[0017]

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

[0019] Step 1: Disperse corn starch in deionized water, stir for 30 minutes, then heat up to 85-90°C, continuously stir for 30 minutes until completely gelatinized to form a transparent colloid, and then cool down to 50°C, add a dispersant, and perform homogenization treatment to obtain a starch gelatinization solution;

[0020] Step 2: Dissolve chitosan powder in a pH regulator, stir magnetically for 2 hours, adjust the pH to 5.0-5.5, let it stand for defoaming and reserve to obtain a chitosan solution;

[0021] Step 3: Immerse the hydroxyapatite nanowires in a silane coupling agent ethanol solution, perform ultrasonic treatment for 30 minutes, then perform centrifugal separation and vacuum dry at 60°C to obtain modified hydroxyapatite nanowires;

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

[0023] Preferably, the pH regulator is selected from citric acid or malic acid.

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

[0025] Preferably, the pressure fluctuation frequency of the pulse pressing is 0.5 - 1.0 Hz, the pressing time is 20 - 30 minutes, and the residual oil rate of the pressed cake 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°C, and the vacuum degree is ≤50 Pa.

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

[0028] 1. Through three-stage low-temperature drying, the present invention gradually dehydrates to avoid the thermal decomposition of flavor substances caused by sudden temperature rise. Infrared rays assist in selectively exciting the vibration of water molecules to accelerate dehydration without damaging macromolecular flavor substances;

[0029] 2. By adding the starch-chitosan composite liquid, the present invention enables the gelatinized starch to form a continuous colloidal network. Chitosan is embedded in the network through hydrogen bonds, improving the density of the membrane layer, blocking oxygen permeation. Moreover, the modified hydroxyapatite nanowires act as a "skeleton" to extend the oxygen diffusion path, and the interfacial bonding strength with the matrix is enhanced through the silane coupling agent to avoid pressing rupture. At the same time, vitamin E is embedded in the membrane layer and gradually migrates to the oil phase during the oil release stage, continuously capturing free radicals and blocking the oxidation chain reaction. The starch-chitosan composite liquid realizes multiple functions of antioxidant, antibacterial, and physical barrier through the compounding of natural components and the strengthening of nanostructures, significantly improving the stability of oleic acid while retaining the original fragrance of peanut oil. The technical effects are clear and have industrialization potential. Specific embodiments

[0030] The following will describe the technical solutions in the embodiments of the present invention clearly and completely in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0031] The above technical solutions will be described in detail by the following embodiments of the present invention:

[0032] Embodiment 1

[0033] A method for extracting high-oleic acid peanut oil with original flavor includes the following steps: First, the dehulled high-oleic acid peanuts are screened by a vibrating screening device. The oleic acid content of the high-oleic acid peanuts is ≥78%, and the impurities in the high-oleic acid peanuts are screened out to obtain peanut raw materials. Then, the screened peanut raw materials are dried in three-stage low-temperature gradient, with the temperatures being 40°C, 50°C, and 60°C respectively, and the drying time for each stage being 20 minutes. Infrared-assisted dehydration is used, and the total moisture content is controlled at 3%. The infrared wavelength is 800nm, and the power density is 0.5W / cm 2 , the ozone sterilization concentration is 0.5mg / L, and the treatment time is 10 minutes. Then, the dried peanut raw materials are immersed in a coating liquid composed of a starch-chitosan composite solution, and the negative pressure adsorption technology is used to make the coating liquid evenly cover the surface of the peanut raw materials. After drying, an antioxidant barrier is formed. Then, the coated peanut raw materials are crushed by a crusher to be peanut crumbs. Finally, the peanut crumbs are subjected to pulsed pressing at a pressure of 20MPa and a temperature ≤45°C. The pressure fluctuation frequency of the pulsed pressing is 1.0Hz, and the pressing time is 20 minutes. The residual oil rate of the pressed cake is ≤10%. The pressed oil is purified by low-temperature filtration and molecular distillation. The low-temperature filtration uses a ceramic membrane with a pore size of 0.5μm, the molecular distillation temperature is 90°C, and the vacuum degree is ≤50Pa to obtain high-oleic acid peanut oil.

[0034] Among them, the mass fractions of the components of the starch-chitosan composite solution raw materials are specifically:

[0035]

[0036] Among them, the preparation steps of the starch-chitosan composite solution are specifically as follows: First, disperse corn starch in deionized water with a solid content of 15%, stir for 30 minutes, then heat up to 90°C and continuously stir for 30 minutes until complete gelatinization to form a transparent colloid. Then cool down to 50°C, add polyoxyethylene sorbitan monooleate, and perform homogenization treatment at a pressure of 20 MPa for 3 cycles to obtain a starch gelatinization solution; then dissolve chitosan powder in a pH regulator, stir magnetically for 2 hours, adjust the pH to 5.5, let it stand for defoaming and reserve to obtain a chitosan solution; then immerse hydroxyapatite nanowires in a 3% silane coupling agent (KH-550) ethanol solution, perform ultrasonic treatment for 30 minutes, then centrifuge and separate, and vacuum dry at 60°C to obtain modified hydroxyapatite nanowires; finally, mix the starch gelatinization solution, chitosan solution, and modified hydroxyapatite nanowires in proportion, add vitamin E, stir magnetically for 1 hour, and perform high-pressure homogenization at 50 MPa for 2 cycles to form a uniformly dispersed starch-chitosan composite solution.

[0037] In this example, the chitosan powder is purchased from Shandong Guante Biotechnology Co., Ltd.; the hydroxyapatite nanowires are purchased from Shaanxi Yiming Biotechnology Co., Ltd.; the corn starch is purchased from the corn starch sold by Aladdin Biochemical Technology Co., Ltd., and vitamin E is purchased from Anhui Zhonghong Biotechnology Co., Ltd.

[0038] It should be noted that in this example, through three-stage low-temperature drying (40°C → 50°C → 60°C), dehydration is gradually carried out to avoid thermal decomposition of flavor substances caused by sudden temperature rise. At the same time, infrared rays are used to assist in selectively exciting the vibration of water molecules to accelerate dehydration without destroying macromolecular flavor substances (such as the melting point of pyrazine compounds is 80 - 100°C and is stable at low temperatures), and ozone is used to replace high-temperature sterilization. Ozone inactivates microorganisms at room temperature, avoiding the excessive consumption of free amino acids (flavor precursors) caused by the Maillard reaction during traditional high-temperature sterilization, so that the retention rate of key volatile substances in high-oleic acid peanut oil (such as 2,5-dimethylpyrazine, furanone) is ≥ 90%.

[0039] It should be explained that in this example, a starch-chitosan composite solution is used. By gelatinizing starch to form a continuous colloidal network, chitosan is embedded in the network through hydrogen bonds, the density of the membrane layer is increased, the porosity is ≤ 5%, the oxygen permeability is blocked, and the oxygen transmission rate is reduced by 60%. At the same time, the modified hydroxyapatite nanowires act as a "skeleton" to extend the oxygen diffusion path, and the interfacial bonding strength with the matrix is improved through the silane coupling agent to avoid squeezing and cracking. Moreover, vitamin E is embedded in the membrane layer and gradually migrates to the oil phase during the oil release stage, continuously capturing free radicals and blocking the oxidation chain reaction, which can improve the storage time of peanut oil after opening and facilitate the consumption of users.

[0040] Example 2

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

[0042] Example 3

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

[0044] Example 4

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

[0046] Comparative Example 1

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

[0048] Comparative Example 2

[0049] The difference between this comparative example and Example 1 is only that: in this comparative example, the starch-chitosan composite liquid does not add chitosan powder, and other conditions are the same.

[0050] Comparative Example 3

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

[0052] Comparative Example 4

[0053] The difference between this comparative example and Example 1 is only that: in this comparative example, the starch-chitosan composite liquid does not add vitamin E, and other conditions are the same.

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

[0055] Detection of oleic acid content: High-oleic acid peanut oil samples prepared in Examples 1-4 and Comparative Examples 1-4 were respectively used to detect the oleic acid content in peanut oil with reference to GB5009.168-2016. The oleic acid was calculated based on the total fatty acid content, and the data was recorded;

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

[0057] Detection of acid value: High-oleic acid peanut oil samples prepared in Examples 1-4 and Comparative Examples 1-4 were respectively used to detect the acid value (calculated as KOH) of peanut oil with reference to GB / T5530-2005 Determination of acid value and acidity of animal and vegetable oils, and the data was recorded;

[0058] Oxidation stability test: High-oleic acid peanut oil samples prepared in Examples 1-4 and Comparative Examples 1-4 were respectively used. For the peroxide value (PV) and acid value (AV), the determination was carried out with reference to GB 5009.227-2016. For the accelerated oxidation experiment (stored at 60°C for 30 days), the thiobarbituric acid value (TBARS) was determined, and the data was recorded;

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

[0060]

[0061] Table 1

[0062] It can be seen from the data in Table 1 above that 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 those in Example 1. From Examples 3 and 4, it can be seen that when the amounts of chitosan powder, hydroxyapatite nanowires, and vitamin E gradually increased, the effects of oleic acid, oil yield, acid value, and peroxide value would gradually decrease. From the data, the higher the amounts of chitosan powder, hydroxyapatite nanowires, and vitamin E, the more the effects of oleic acid, oil yield, acid value, and peroxide value decreased. However, abnormal data occurred when adding more chitosan powder, hydroxyapatite nanowires, and vitamin E, and it did not bring better effects. Therefore, it can be seen from Example 1 that when there are 3 parts of chitosan powder, 7 parts of hydroxyapatite nanowires, and 0.4 part of vitamin E, the effects of oleic acid, oil yield, acid value, and peroxide value of the high-oleic acid peanut oil are the best;

[0063] From the data of Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4, it can be seen that in the preparation process of the starch-chitosan composite solution in Comparative Example 2, chitosan powder was not added. Compared with Example 1, the oleic acid, oil yield and acid value of the high-oleic acid peanut oil prepared in Comparative Example 2 were all smaller than those in Example 1, and the peroxide value of the high-oleic acid peanut oil prepared in Comparative Example 2 was greater than that in Example 1. Moreover, the peroxide values of the high-oleic acid peanut oil prepared in Comparative Example 3 and Comparative Example 4 were greater than those in Comparative Example 2, indicating that the role of chitosan is greater than that of hydroxyapatite nanowires and vitamin E. A continuous colloidal network is formed through gelatinized starch, and chitosan is embedded in the network through hydrogen bonds, improving the density of the film layer, with a porosity ≤ 5%, blocking oxygen penetration, and reducing the oxygen permeability by 60%. It realizes multiple functions of antioxidant and physical barrier, significantly improving the oleic acid stability while retaining the original aroma of peanut oil;

[0064] The data of Comparative Example 1 shows that the existing single starch composite solution has poor effects. The data of Comparative Example 1 is quite different from that of Examples 1-4, indicating that although using a single starch composite solution can achieve certain effects, compared with the starch-chitosan composite solution in Examples 1-4, the gap is still large. It shows that gelatinized starch can form a continuous colloidal network, chitosan is embedded in the network through hydrogen bonds, improving the density of the film layer and blocking oxygen penetration. Moreover, the modified hydroxyapatite nanowires act as a "skeleton" to extend the oxygen diffusion path, and the interfacial bonding strength with the matrix is improved through a silane coupling agent to avoid crushing during pressing. 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, enabling the starch-chitosan composite solution to be strengthened by the compounding of natural components and nanostructures;

[0065] Example 1 can be preferably selected from the above table data.

[0066] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

Claims

1. A method for extracting high-oleic acid peanut oil with original flavor, characterized in that: It includes the following steps: S1. Screening: The peeled peanut raw materials are screened by a vibrating screening device to remove impurities in the peanut raw materials, and peanut raw materials are obtained; S2. Pretreatment: The screened peanut raw materials are dried in a three-stage low-temperature gradient successively and infrared-assisted dehydration is adopted, and the total moisture content is controlled at 3%-4%; S3. Coating treatment: The dried peanut raw materials are immersed in a coating solution composed of a starch-chitosan composite solution, and the negative pressure adsorption technology is adopted to make the coating solution evenly cover the surface of the peanut raw materials, and an antioxidant barrier is formed after drying; S4. Crushing: The coated peanut raw materials are crushed by a crusher, and the peanut granules are crushed into peanut crumbs; S5. Low-temperature pressing: The peanut crumbs are subjected to pulsed pressing under the conditions of a pressure of 10-50 MPa and a temperature ≤45°C. After pressing, the oil is purified by low-temperature filtration and molecular distillation to obtain high-oleic acid peanut oil.

2. The method for extracting high-oleic acid peanut oil with original fragrance flavor as described in claim 1, characterized in that: The peanut raw materials are selected as high-oleic acid peanuts, and the oleic acid content ≥78%; 3. The method for extracting high-oleic acid peanut oil with original fragrance flavor according to claim 1, characterized in that: In step S2, the temperatures of the low-temperature gradient drying are 40°C, 50°C and 60°C respectively, and the drying time for each stage is 20-30 minutes; 4. The method for extracting high-oleic acid peanut oil with original fragrance flavor according to claim 3, characterized in that: In step S2, the infrared wavelength is 800 - 1200 nm, the power density is 0.5 - 1.0 W / cm 2 , the ozone sterilization concentration is 0.5 - 1.0 mg / L, and the treatment time is 10 - 15 minutes.

5. The method for extracting high-oleic acid peanut oil with original fragrance flavor according to claim 3, characterized in that: The specific mass fractions of the components of the starch-chitosan composite solution raw materials are:

6. The method for extracting high-oleic acid peanut oil with original fragrance flavor according to claim 5, characterized in that: The specific preparation steps of the starch-chitosan composite solution are: Step 1. Corn starch is dispersed in deionized water, stirred for 30 minutes, then heated to 85-90°C, continuously stirred for 30 minutes until completely gelatinized to form a transparent colloid, and then cooled to 50°C, a dispersant is added, and homogenization treatment is carried out to obtain a starch gelatinization solution; Step 2. Chitosan powder is dissolved in a pH regulator, magnetically stirred for 2 hours, the pH is adjusted to 5.0-5.5, and it is left standing for defoaming for standby to obtain a chitosan solution; Step 3. Hydroxyapatite nanowires are immersed in a silane coupling agent ethanol solution, ultrasonically treated for 30 minutes, then centrifuged and dried in vacuum at 60°C to obtain modified hydroxyapatite nanowires; Step 4. The starch gelatinization solution, the chitosan solution and the modified hydroxyapatite nanowires are mixed in proportion, vitamin E is added, magnetically stirred for 1 hour, and high-pressure homogenization is carried out to form a uniformly dispersed starch-chitosan composite solution.

7. The method for extracting high-oleic acid peanut oil with original fragrance flavor according to claim 5, characterized in that: The pH regulator is selected from citric acid or malic acid; 8. The method for extracting high-oleic acid peanut oil with original fragrance flavor as described in claim 5, characterized in that: The dispersant is selected from polyoxyethylene sorbitan monooleate or methyl cellulose; 9. The method for extracting high-oleic acid peanut oil with original fragrance flavor according to claim 1, characterized in that: The pressure fluctuation frequency of the pulsed pressing is 0.5-1.0 Hz, the pressing time is 20-30 minutes, and the residual oil rate of the pressed cake ≤10%; 10. The method for extracting high-oleic acid peanut oil with original fragrance flavor according to claim 1, characterized in that: The low-temperature filtration adopts a ceramic membrane with a pore size of 0.1-0.5 μm, the molecular distillation temperature is 80-90°C, and the vacuum degree ≤50 Pa.

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