A production method of a selenium-rich peanut oil system

Abstract

The application belongs to the field of edible oil processing, and specifically discloses a production method of selenium-rich peanut oil system, which comprises the following steps: S1, breaking the selenium-rich peanuts with a seed organic selenium content of greater than or equal to 1.2 mg / kg after pulse strong light enzyme inactivation treatment; S2, releasing oil from the peanut raw materials through low-temperature wall-breaking primary pressing, and then extracting residual oil through gradient temperature secondary pressing; S3, filtering and degumming the crude oil through a ceramic membrane molecular sieve; S4, adding immobilized lipase to the degummed oil for catalytic deacidification; S5, making the deacidified oil flow through an activated carbon fiber membrane for decolorization; and S6, treating the decolorized oil through molecular distillation and deodorization treatment. The application combines pulse strong light enzyme inactivation, gradient low-temperature pressing and membrane integrated refining, controls temperature throughout the process to avoid thermal denaturation, and replaces chemical methods with membrane refining, so that high selenium retention of the selenium-rich peanut oil is achieved, solvent and strong alkali residues are eliminated through physical pressing and enzymatic deacidification, and the working hours and residual oil rate are shortened through membrane refining.

Description

Technical Field

[0001] This invention belongs to the field of edible oil processing, and specifically relates to a production method of a selenium-enriched peanut oil system. Background Technology

[0002] Selenium is an essential trace element for the human body, with physiological functions such as anti-oxidation and enhancing immunity.

[0003] Selenium-enriched peanuts are a special type of peanut cultivated through selenium biofortification. The organic selenium content in the kernels can reach 1.2-1.5 mg / kg (compared to ≤0.05 mg / kg for ordinary peanuts). Peanut oil is rich in nutrients such as unsaturated fatty acids and vitamin E. Combining these with selenium to prepare selenium-enriched peanut oil can combine the health benefits of both, meeting the development needs of modern functional foods.

[0004] However, traditional oil processing uses hot drying and single-stage high-temperature pressing processes that damage the structure of selenoproteins, causing selenium to volatilize in the form of H2Se, resulting in a high selenium loss rate. Furthermore, chemical refining (such as alkali refining for deacidification and high-temperature steam distillation for deodorization) further damages the selenium form. Summary of the Invention

[0005] The purpose of this invention is to provide a production method for a selenium-enriched peanut oil system, so as to solve the problems of selenium loss and chemical residues in the traditional processing technology mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for producing selenium-enriched peanut oil includes:

[0008] S1. After treating the selenium-enriched peanuts with an organic selenium content ≥1.2mg / kg with pulsed strong light to inactivate enzymes, the peanuts were crushed to a particle size of 0.5-2mm under nitrogen atmosphere to obtain peanut raw materials.

[0009] S2. The peanut raw material is subjected to low-temperature cell wall breaking primary pressing to release oil, followed by gradient heating secondary pressing to extract residual oil, to obtain crude oil;

[0010] S3. Degumming crude oil is obtained by filtering it through a ceramic membrane molecular sieve.

[0011] S4. Add immobilized lipase to the degummed oil to catalyze deacidification and obtain deacidified oil;

[0012] S5. Decolorize the deacidified oil by passing it through an activated carbon fiber membrane to obtain decolorized oil;

[0013] S6. The decolorized oil is deodorized by molecular distillation to obtain refined selenium-enriched peanut oil.

[0014] Preferably, the selenium-enriched peanuts are obtained by root application of nano-selenium fertilizer and foliar spraying of selenomic acid solution. The dosage of the root application of nano-selenium fertilizer is 0.5-1.0 mg / kg soil, and the concentration of selenomic acid in the foliar spraying of selenomic acid solution is 0.1-0.3%, and the number of sprays is 3 times per growing season.

[0015] Preferably, the light intensity for pretreatment of the raw materials using pulsed light enzyme inactivation technology is 0.8 J / cm², the number of pulses is 3 pulses / s, and the treatment time is 30-40s.

[0016] Preferably, the primary pressing temperature is 35-40℃ and the pressure is 20-25MPa.

[0017] Preferably, the secondary pressing gradient is heated to 55-60°C and the pressure is 35-40 MPa.

[0018] Preferably, the temperature difference between the primary pressing and the secondary pressing is ≥15℃.

[0019] Preferably, the ceramic membrane molecular sieve has a pore size of 0.1-0.2 μm and a degumming temperature of 40°C; the catalytic deacidification temperature is 55°C, the enzyme content is 0.1-0.3%, and the catalytic time is 90 min; the activated carbon fiber membrane decolorization temperature is 65°C and the flow rate is 1.5 L / min; and the molecular distillation temperature is 80°C and the vacuum degree is 100-500 Pa.

[0020] Preferably, after obtaining the refined selenium-enriched peanut oil:

[0021] 0.1% rosemary extract was mixed with 0.05% vitamin E, encapsulated in β-cyclodextrin solution, and then spray-dried to obtain antioxidant microcapsule powder;

[0022] Add the microcapsule powder to the refined selenium-enriched peanut oil and stir for 30 minutes at 50°C and 200 rpm to disperse it evenly.

[0023] Preferably, the spray drying parameters are an inlet air temperature of 110°C and an outlet air temperature of 65°C.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] This invention combines pulsed high-intensity light enzyme inactivation, gradient low-temperature pressing, and membrane integrated refining. The entire process is temperature-controlled to avoid thermal denaturation, and membrane refining replaces chemical methods, achieving high selenium retention in selenium-rich peanut oil. Physical pressing and enzymatic deacidification eliminate solvent and strong alkali residues, avoiding chemical pollution. Membrane refining shortens working time and reduces residual oil rate, resulting in significant overall efficiency improvement. Detailed Implementation

[0026] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below.

[0027] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0028] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0029] Example 1: This example provides a production method for a selenium-enriched peanut oil system, including:

[0030] S1. Selenium-enriched peanuts with an organic selenium content of 1.4 mg / kg were treated with pulsed strong light to inactivate enzymes, and then crushed to a particle size of 1-1.5 mm under nitrogen atmosphere to obtain peanut raw materials.

[0031] Specifically, Yunnan peanuts were selected and planted in sandy loam soil with a pH of 6.5-7.0. During the seedling stage, nano-selenium fertilizer was applied to the roots and selenomic acid solution was sprayed on the leaves. The dosage of nano-selenium fertilizer applied to the roots was 0.8 mg / kg of soil, and the concentration of selenomic acid solution sprayed on the leaves was 0.2%. The spraying was done once each during the flowering, pod-setting, and grain-filling stages. After harvest, the organic selenium content of the grains was tested and found to be 1.4 mg / kg (organic selenium accounted for 88%).

[0032] Specifically, the light intensity for pretreatment of raw materials using pulsed light enzyme inactivation technology is 0.8 J / cm² (wavelength 200-1100 nm), the number of pulses is 15, and the treatment time is 35 s.

[0033] Pulsed intense light destroys the active sites of enzymes (such as lipoxygenase) through high-energy short-wave ultraviolet light, inhibiting oxidation reactions; the nitrogen environment isolates oxygen, preventing the loss of selenium through oxidation during the crushing process.

[0034] Results: The selenium loss rate after enzyme inactivation is only 2.1%, and the proportion of organic selenium is maintained at over 95%; low-temperature crushing protects the selenoprotein structure, laying the foundation for selenium retention in subsequent pressing.

[0035] S2. The peanut raw material is subjected to low-temperature cell wall breaking primary pressing to release oil, followed by gradient temperature secondary pressing to extract residual oil, to obtain crude oil (oil yield 95.2%).

[0036] Specifically, the primary pressing temperature is 38℃ and the pressure is 22MPa.

[0037] Specifically, the secondary pressing gradient is heated to 58℃ (heating rate 5℃ / min) and the pressure is 38MPa.

[0038] Specifically, the temperature difference between primary and secondary pressing is ≥15℃.

[0039] The first stage of low-temperature cell disruption (≤40℃) reduces lipid oxidation and selenoprotein denaturation; the second stage of gradient heating utilizes temperature differences to promote cell rupture and release residual oil.

[0040] Results: Oil yield reaches 95.2%, residual oil rate is as low as 4.8%, selenium retention rate exceeds 92%, avoiding the decomposition of selenoprotein caused by high temperature, and the finished product has a selenium content of 1.28mg / kg.

[0041] S3. Degumming crude oil by filtering it through a ceramic membrane molecular sieve to obtain degummed oil (phospholipid content ≤0.05%).

[0042] Membrane filtration utilizes the pore size sieving effect to trap colloidal impurities such as phospholipids, and low-temperature operation avoids oil oxidation.

[0043] Effects: Phospholipid content is reduced to ≤0.05%, providing a pure system for subsequent deacidification and reducing enzyme activity inhibition.

[0044] S4. Add immobilized lipase (from Rhizopus oryzae) to the degummed oil for catalytic deacidification to obtain deacidified oil (acid value 0.4 mg KOH / g).

[0045] Immobilized enzymes selectively catalyze the esterification of free fatty acids, reducing acid value, while enzyme immobilization allows for reuse, reducing pollution;

[0046] Effect: The acid value decreased from the initial 1.2 mg KOH / g to below 0.4 mg KOH / g.

[0047] S5. The deacidified oil is passed through an activated carbon fiber membrane to obtain decolorized oil (color R1.5, Y15).

[0048] Activated carbon fiber has a high specific surface area to adsorb chlorophyll, carotenoids, etc., and low-temperature flow rate control avoids excessive adsorption and oil loss.

[0049] The color was reduced from R3.0 / Y20 to R1.5 / Y15, and trace metal residues were avoided as a result of traditional activated clay decolorization.

[0050] S6. The decolorized oil was deodorized by molecular distillation to obtain refined selenium-enriched peanut oil (peroxide value 0.05 meq / kg).

[0051] Molecular distillation utilizes the difference in mean free path of molecules of different substances to separate volatile odorous substances (such as aldehydes and ketones) under low vacuum and low temperature.

[0052] Results: Peroxide value was reduced to 0.05 meq / kg, odor was removed while avoiding selenium volatilization caused by high temperature (such as traditional steam distillation at 180℃), and benzo[a]pyrene was not detected.

[0053] Specifically, the ceramic membrane molecular sieve has a pore size of 0.15 μm, a degumming temperature of 40℃, a catalytic deacidification temperature of 55℃, an enzyme content of 0.2%, and a catalytic time of 90 min; the activated carbon fiber membrane has a decolorization temperature of 65℃ and a flow rate of 1.5 L / min; the molecular distillation temperature is 80℃; and the vacuum degree is 300 Pa.

[0054] Specifically, after obtaining refined selenium-enriched peanut oil:

[0055] 0.1% rosemary extract was mixed with 0.05% vitamin E, encapsulated in 5% β-cyclodextrin solution, and then spray-dried to obtain antioxidant microcapsule powder;

[0056] Add the microcapsule powder to the refined selenium-enriched peanut oil and stir for 30 minutes at 50°C and 200 rpm to disperse it evenly.

[0057] Specifically, the spray drying parameters are an inlet air temperature of 110℃ and an outlet air temperature of 65℃.

[0058] β-Cyclodextrin is encapsulated to form microcapsules, protecting antioxidants from photo-oxidative damage; spray drying and low-temperature curing prevent degradation of active ingredients;

[0059] Effects: Shelf life exceeds 24 months at 60℃, peroxide value growth rate is reduced by 50%, achieving "slow-release antioxidant".

[0060] As can be seen from the above: enzyme inactivation blocks the decomposition pathway of selenoproteins, low temperature avoids the volatilization of selenium in the form of H2Se, and gradient pressing reduces the damage of temperature to the selenium form while ensuring oil yield. This allows pulsed light to inactivate enzymes (reduce enzymatic oxidation), nitrogen gas to break down the enzymes (prevent oxidation), and low temperature gradient pressing (prevent heat denaturation) to jointly improve the selenium retention rate.

[0061] The ceramic membrane degumming (removing impurities), lipase deacidification (precise acid reduction), activated carbon fiber membrane decolorization (adsorbing pigments), and molecular distillation deodorization (low-temperature deodorization) together form a "gradient refining" system, avoiding the nutrient loss caused by traditional chemical refining (such as alkali refining and high-temperature decolorization);

[0062] The triple action of microencapsulation (physical protection), low-temperature refining (reducing the formation of oxidative substrates), and the antioxidant properties of the raw material selenium (selenoamino acids scavenge free radicals) allows the microcapsules to slowly release antioxidants, which work synergistically with selenium to block the lipid peroxidation chain reaction, extending the shelf life by more than 100%.

[0063] Example 2: This example is basically the same as Example 1, except that the pulse enzyme inactivation time is shortened to 30s.

[0064] The test results are shown in the table below:

[0065] Testing items Example 1 Example 2 Raw material selenium (mg / kg) 1.40 1.40 Selenium loss (%) after enzyme inactivation 2.1 5.3 Selenium retention after pressing (%) 92.7 92.1 Selenium retention after refining (%) 91.4 90.2 Finished selenium (mg / kg) 1.28 1.26 Organic selenium content (%) 95.2 94.8 Peroxide value (meq / kg) 0.05 0.07 Acid value (mgKOH / g) 0.40 0.42 Benzo[a]pyrene (μg / kg) Not detected Not detected Shelf life (months, 60℃) 24+ 22

[0066] Results: The residual activity of lipoxygenase was 12% (2% in Example 1), which resulted in: an increase in free fatty acids during the pressing process, leading to an acid value of +0.02 mg KOH / g; and accelerated oxidation during storage, resulting in a 2-month shortened shelf life.

[0067] Example 3: This example is basically the same as Example 1, except that the first pressing is performed at 40℃ / 25MPa.

[0068] The test results are shown in the table below:

[0069] Testing items Example 1 Example 3 Raw material selenium (mg / kg) 1.40 1.40 Selenium loss (%) after enzyme inactivation 2.1 2.0 Selenium retention after pressing (%) 92.7 88.4 Selenium retention after refining (%) 91.4 85.6 Finished selenium (mg / kg) 1.28 1.19 Organic selenium content (%) 95.2 93.1 Peroxide value (meq / kg) 0.05 0.12 Acid value (mgKOH / g) 0.40 0.48 Benzo[a]pyrene (μg / kg) Not detected 0.2 Shelf life (months, 60℃) 24+ 18

[0070] Results: Local temperatures exceeding 60°C during pressing increased selenoprotein denaturation (selenium retention rate decreased by 4.7%), and the rapid decrease in oil viscosity led to an increase in residual oil content to 8.1% (compared to 4.8% in Example 1).

[0071] Comparative examples: Two control groups were compared with the selenium-enriched peanut oil prepared in Example 1. The two control groups were basically the same as those in Example 1, except that control group 1 used traditional heat-curing to inactivate enzymes (120℃), while control group 2 used single-stage high-temperature pressing (120℃).

[0072] The test results are shown in the table below:

[0073] Testing items Example 1 Comparison Group 1 Comparison Group 2 Raw material selenium (mg / kg) 1.40 1.40 1.40 Selenium loss (%) after enzyme inactivation 2.1 28.7 2.5 Selenium retention after pressing (%) 92.7 71.3 65.2 Selenium retention after refining (%) 91.4 52.1 48.7 Finished selenium (mg / kg) 1.28 0.73 0.68 Organic selenium content (%) 95.2 76.3 74.5 Peroxide value (meq / kg) 0.05 0.15 0.18 Acid value (mgKOH / g) 0.40 0.52 0.60 Benzo[a]pyrene (μg / kg) Not detected 1.2 2.7 Shelf life (months, 60℃) 24+ 12 10

[0074] Results: Pulsed light inactivation of enzymes increased selenium retention by 27.5 percentage points after pressing. Low-temperature gradient pressing avoids thermal denaturation (120℃ causes selenoprotein decomposition) and is less likely to cause thermal denaturation of selenoproteins, reducing the loss of free selenium. At the same time, the low temperature results in a low cell wall breakage rate, which does not easily destroy the selenium form. This makes the selenium retention rate 75.4% higher than that of traditional processes. Membrane refining avoids the formation of carcinogenic benzo[a]pyrene at high temperatures, and microencapsulation selenium preservation technology delays oxidation, doubling the shelf life.

[0075] This invention takes "low-temperature bioactivity protection + membrane separation for precise refining + microcapsule anti-oxidation" as its main technical line, and constructs a full-chain selenium retention system from raw material planting to finished product packaging;

[0076] At the planting stage, by applying nano-selenium fertilizer to the roots and foliar spraying selenomic acid, inorganic selenium is converted into organic selenium (selenoproteins, selenoamino acids) through plant metabolism, laying the foundation for high organic selenium content.

[0077] At the processing end, pulsed intense light non-thermal processing is used to inactivate oxidases and prevent selenium degradation; nitrogen crushing and low-temperature gradient pressing are combined to physically break down cell walls while isolating oxygen and controlling temperature to avoid denaturation of selenoproteins; membrane technology refining is used to replace traditional chemical processing, precisely removing impurities at low temperatures while retaining selenium and unsaturated fatty acids; molecular distillation at low temperatures is used for deodorization to avoid high temperatures damaging the selenium form; and natural antioxidants are encapsulated to delay oil oxidation and stabilize the environment in which selenium exists.

[0078] The final product is a selenium-enriched edible oil with "high organic selenium content (≥1.2mg / kg) + low oxidation index (peroxide value ≤0.05meq / kg) + long shelf life (more than 24 months)," achieving a balance between nutrition and stability.

[0079] It should be understood that numerous specific implementation decisions can be made during the development of any practical implementation, such as in any engineering or design project. Such development efforts may be complex and time-consuming, but for those skilled in the art who benefit from this disclosure, the development effort will be a routine work of design, manufacturing, and production without requiring much experimentation.

[0080] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for producing selenium-enriched peanut oil, characterized in that, include: S1. After treating the selenium-enriched peanuts with an organic selenium content ≥1.2mg / kg with pulsed strong light to inactivate enzymes, the peanuts were crushed to a particle size of 0.5-2mm under nitrogen atmosphere to obtain peanut raw materials. S2. The peanut raw material is subjected to low-temperature cell wall breaking primary pressing to release oil, followed by gradient heating secondary pressing to extract residual oil, to obtain crude oil; S3. Degumming crude oil is obtained by filtering it through a ceramic membrane molecular sieve. S4. Add immobilized lipase to the degummed oil to catalyze deacidification and obtain deacidified oil; S5. Decolorize the deacidified oil by passing it through an activated carbon fiber membrane to obtain decolorized oil; S6. The decolorized oil is deodorized by molecular distillation to obtain refined selenium-enriched peanut oil.

2. The production method of a selenium-enriched peanut oil system according to claim 1, characterized in that, The selenium-enriched peanuts are obtained by applying nano-selenium fertilizer to the roots and spraying selenomic acid solution on the leaves. The dosage of the nano-selenium fertilizer applied to the roots is 0.5-1.0 mg / kg soil, and the concentration of selenomic acid in the selenomic acid solution sprayed on the leaves is 0.1-0.3%, and the number of sprays is 3 times per growing season.

3. The production method of a selenium-enriched peanut oil system according to claim 1, characterized in that, The light intensity for pretreatment of raw materials using pulsed light enzyme inactivation technology is 0.8 J / cm², the number of pulses is 3 pulses / s, and the treatment time is 30-40s.

4. The production method of a selenium-enriched peanut oil system according to claim 1, characterized in that, The primary pressing temperature is 35-40℃ and the pressure is 20-25MPa.

5. The production method of a selenium-enriched peanut oil system according to claim 1, characterized in that, The secondary pressing gradient is heated to 55-60℃ and the pressure is 35-40MPa.

6. The production method of a selenium-enriched peanut oil system according to claim 1, characterized in that, The temperature difference between the primary and secondary pressing is ≥15℃.

7. The production method of a selenium-enriched peanut oil system according to claim 1, characterized in that, The ceramic membrane molecular sieve has a pore size of 0.1-0.2 μm and a degumming temperature of 40℃. The catalytic deacidification temperature is 55℃, the enzyme amount is 0.1-0.3%, and the catalytic time is 90 min. The activated carbon fiber membrane decolorization temperature is 65℃ and the flow rate is 1.5 L / min. The molecular distillation temperature is 80℃ and the vacuum degree is 100-500 Pa.

8. The production method of a selenium-enriched peanut oil system according to claim 1, characterized in that, After obtaining the refined selenium-enriched peanut oil: 0.1% rosemary extract was mixed with 0.05% vitamin E, encapsulated in β-cyclodextrin solution, and then spray-dried to obtain antioxidant microcapsule powder; Add the microcapsule powder to the refined selenium-enriched peanut oil and stir for 30 minutes at 50°C and 200 rpm to disperse it evenly.

9. The production method of a selenium-enriched peanut oil system according to claim 8, characterized in that, The spray drying parameters are: inlet air temperature 110℃ and outlet air temperature 65℃.