Green flexible processing technology for improving the antioxidant capacity and quality stability of linseed oil and the oil prepared by the technology

Abstract

The present application relates to the field of oil processing, and discloses a green flexible processing technology for improving the antioxidant capacity and quality stability of flaxseed oil and oil prepared by the technology. The method comprises the following steps: (1) determining the content of cyclic peptide substances in flaxseed crude oil, calculating the amount of acidic substances according to formula (I), mixing flaxseed crude oil with acidic substances for debittering to obtain debittered oil; C=a×A+b×B+c (I); C is the amount of acidic substances, A is the total content of cyclic peptide substances in flaxseed crude oil, B is the total content of cyclic peptide P and cyclic peptide E in flaxseed crude oil; a, b and c are constants, 12≤a≤20, 9≤b≤16; -15≤c≤0; (2) deacidifying the debittered oil to obtain deacidified oil. The method can not only efficiently remove bitter peptides in flaxseed oil, but also improve the oxidation stability of refined flaxseed oil by more than 20%, thereby solving the problem that debittering and oxidation stability of flaxseed crude oil cannot be achieved simultaneously.

Description

Technical Field

[0001] This invention relates to the field of oil processing, specifically to a green and flexible processing technology for improving the antioxidant capacity and quality stability of flaxseed oil and the oil prepared therefrom. Background Technology

[0002] Flax is the fourth largest oilseed crop after rapeseed, soybeans, and peanuts. Flaxseed oil, obtained after pressing, is an important source of various functional active ingredients such as alpha-linolenic acid (ALA), vitamins, lignans, and linolenic acid cyclic peptides (CLs).

[0003] Flaxseed cyclic peptides are a class of hydrophobic cyclic peptides naturally found in flaxseeds and flax roots, with a molecular weight of approximately 1000 Da and composed of eight to ten amino acid residues. Flaxseed cyclic peptides contain more than ten types of cyclic peptides, such as cyclic peptides A / C / F / G / P, which are non-bitter. However, during storage, cyclic peptide P oxidizes to form cyclic peptide E, which enhances the bitterness of the product, resulting in a strong bitter taste in flaxseed oil.

[0004] Currently, the most researched methods for removing bitter substances from flaxseed oil are adsorption and enzymatic hydrolysis. Enzymatic hydrolysis is costly and not suitable for large-scale production; therefore, existing methods for debittering flaxseed oil mainly rely on adsorption. For example, the study "Zhu Zhengwei et al., Research on Flaxseed Pressing Oil Extraction and Adsorption Refining Process [D]. Chinese Academy of Agricultural Sciences, 2015" compared the adsorption effects of five adsorbents—activated clay, activated carbon, modified calcium-based montmorillonite, dephosphorizing agents, and sepiolite—on CLE (Cold Lesion Effluent). The results showed that activated clay had a significantly better adsorption effect than the other adsorbents. CN105112157A discloses a method for debittering and deodorizing flaxseed oil, which includes contacting the flaxseed oil with a mixture of hulled flaxseed meal powder and diatomaceous earth. Using this method, with hulled flaxseed meal powder and diatomaceous earth, the debittering and deodorizing treatment of flaxseed oil can be effectively achieved. "Hu Xiaojun et al., Research on enzymatic removal of bitter substances from flaxseed oil [J]. Agricultural Products Processing, 2014(09):24-26." Bitter flaxseed oil was selected as the experimental raw material. Alkaline protease, neutral protease and acidic protease were used to remove bitterness from bitter flaxseed oil respectively. Through orthogonal experimental design, the optimal combination of debittering conditions for flaxseed oil was obtained as follows: using neutral protease, enzyme activity of 45 U / mL, enzymatic hydrolysis time of 6 h, and enzymatic hydrolysis pH of 7. The debittering effect was the best. Under the optimal conditions, the content of bitter peptides in flaxseed oil was measured to be 13.6 mg / kg.

[0005] Furthermore, crude flaxseed oil obtained through pressing contains a large amount of non-triglyceride components such as pigments, free fatty acids, resins, aflatoxin, tocopherols, proteins, and phospholipids. These pigments and other substances have no nutritional value and severely affect the color of the crude oil. Additionally, trace amounts of phospholipids, soap particles, and metal ions remaining in crude flaxseed oil accelerate its oxidation and rancidity. Therefore, current processes require decolorization of crude flaxseed oil to improve its quality. The most widely used decolorization methods for flaxseed oil are adsorption decolorization, which typically uses adsorbents to adsorb pigments from the crude oil under specific temperature and pressure conditions.

[0006] In summary, while adsorption methods are effective in removing bitter substances or pigments, most adsorbents contain metal ions that promote oxidation of the oil, further reducing the oxidative stability of refined flaxseed oil. In particular, the peroxide value of flaxseed oil rises rapidly after opening, exceeding the requirements of GB / T 2716-2018 "National Food Safety Standard for Vegetable Oils" (peroxide value of crude vegetable oil and edible vegetable oil ≤ 0.25g / 100g, equivalent to peroxide value ≤ 9.85mmol / kg) during its shelf life. Therefore, it is impossible to simultaneously achieve both debittering and oxidative stability in crude flaxseed oil. Summary of the Invention

[0007] The purpose of this invention is to overcome the problem in existing technologies where the refining process (debittering or decolorizing) of crude flaxseed oil cannot simultaneously achieve both debittering and oxidative stability. This invention provides a green, flexible processing technology that enhances the antioxidant capacity and quality stability of flaxseed oil, along with the resulting oil. This method eliminates the need for conventional decolorization, efficiently removing bitter peptides from flaxseed oil while simultaneously increasing the oxidative stability of refined flaxseed oil by more than 20%. Furthermore, the resulting oil has a low initial oxidation value, and its peroxide value still meets national standards after being left open for 8 weeks, demonstrating stable quality. This solves the problem in existing technologies where debittering and oxidative stability of crude flaxseed oil cannot be simultaneously achieved.

[0008] To achieve the above objectives, the first aspect of the present invention provides a method for preparing flaxseed oil, the method comprising the following steps: (1) Determine the content of cyclic peptides in crude flaxseed oil, calculate the amount of acidic substance according to formula (I), mix crude flaxseed oil with acidic substance to debitter, and obtain debittered oil. C = a × A + b × B + c (I); C represents the amount of acidic substances used, in mmol / kg flaxseed oil; a is a calculation coefficient, 12≤a≤20; A represents the total content of cyclic peptides in flaxseed oil, in mmol / kg flaxseed oil; b is a calculation coefficient, 9≤b≤16; B represents the total content of cyclic peptide P and cyclic peptide E in flaxseed oil, in mmol / kg flaxseed oil; c is a constant, -15≤c≤0. (2) Deacidify the debittered oil to obtain deacidified oil.

[0009] A second aspect of the present invention provides flaxseed oil prepared by the method of the present invention.

[0010] A third aspect of the present invention provides the application of the method described herein in removing bitter substances from flaxseed oil and improving the oxidative stability of flaxseed oil.

[0011] Through the above technical solution, the present invention achieves at least the following beneficial technical effects: (1) The method of the present invention can obtain first-grade flaxseed oil without conventional decolorization treatment. Compared with conventional refining process, it avoids the use of mineral adsorbents, reduces production costs, and meets the trend of green processing. In addition, the method of the present invention can not only efficiently remove bitter peptides in flaxseed oil, but also improve the oxidative stability of refined flaxseed oil by more than 20%. The initial oxidation value of the prepared oil is low, and the peroxide value of the finished oil is still ≤9.85mmol / kg after being opened and stored for 8 weeks, which meets the national standard requirements and the quality is stable. This solves the problem that the existing technology cannot achieve both debittering and oxidative stability of flaxseed oil when using adsorption method for debittering or decolorizing flaxseed oil.

[0012] (2) The method of the present invention does not require technical personnel to make judgments based on experience, and can quickly and accurately quantify the amount of acidic substances added. This not only ensures the precision and controllability of the debittering process, but also simplifies the operation threshold from the source, reduces the dependence on the experience of skilled workers, thereby reducing personnel training costs and facilitating the promotion of standardized operations in the industry. Detailed Implementation

[0013] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0014] The first aspect of this invention provides a method for preparing flaxseed oil, the method comprising the following steps: (1) Determine the content of cyclic peptides in crude flaxseed oil, calculate the amount of acidic substance according to formula (I), mix crude flaxseed oil with acidic substance to debitter, and obtain debittered oil. C = a × A + b × B + c (I); C represents the amount of acidic substances used, in mmol / kg flaxseed oil; a is a calculation coefficient, 12≤a≤20; A represents the total content of cyclic peptides in flaxseed oil, in mmol / kg flaxseed oil; b is a calculation coefficient, 9≤b≤16; B represents the total content of cyclic peptide P and cyclic peptide E in flaxseed oil, in mmol / kg flaxseed oil; c is a constant, -15≤c≤0. (2) Deacidify the debittered oil to obtain deacidified oil.

[0015] In this invention, the testing method of formula (I) includes: obtaining the total content of cyclic peptides, the total content of cyclic peptide P and cyclic peptide E in crude flaxseed oil; denoting the total content of cyclic peptides in the crude flaxseed oil as A, the total content of cyclic peptide P and cyclic peptide E as B, and the amount of acidic substance as C; and establishing a regression model of A, B and C using linear regression to fit the formula for the amount of acidic substance.

[0016] In this invention, in order to ensure the complete removal of cyclic peptides from flaxseed oil, preferably, an appropriate amount of excess acid can be added based on the acid content calculated by formula (I); the amount of excess acid is 0.1 mol%-5 mol of the amount of acid.

[0017] In this invention, the amount of acidic substance calculated by the formula fitted by the above method may deviate from the actual amount added. The error between the actual amount added and the calculated value of the relational formula is controlled within ±5%, which is within the protection scope of this invention.

[0018] In this invention, the addition of acidic substances to flaxseed oil by skilled workers based on experience refers to the addition of acidic substances based on sensory indicators such as color of flaxseed oil or a fixed proportion, rather than on the quantitative determination of cyclic peptides A and B in crude flaxseed oil. Therefore, the amount added is not definitively related to the relationship formula of this invention. Moreover, in the specific embodiments of this invention, the amount added by skilled workers based on experience deviates from the calculated value of formula (I) by more than 50%.

[0019] In this invention, the acidic substance is added in the form of an acidic substance-water solution. There is no particular limitation on the mass concentration of the acidic substance-water solution, as long as the amount of acidic substance in the acidic substance-water solution meets the above requirements. In a specific embodiment of this invention, the amount of acidic substance calculated according to formula (I) is converted into an acidic substance-water solution with a mass concentration of 50wt%-85wt% and mixed with crude flaxseed oil. Preferably, the mass concentration of the acidic substance-water solution is 75wt%-85wt%.

[0020] According to some embodiments of the present invention, the acidic substance is selected from at least one of phosphoric acid, citric acid, lactic acid, hydrochloric acid, and sulfuric acid.

[0021] According to some embodiments of the present invention, in step (1), the conditions for debittering include: a temperature of 70°C-80°C and a time of 30-65 min.

[0022] Preferably, the debittering method includes: mixing flaxseed oil with an acidic substance under conditions of 70℃-80℃ and then performing a first stirring and a second stirring.

[0023] In this invention, the debittering time of 30-65 min in step (1) refers to the total time of the first and second stirring.

[0024] Preferably, the conditions for the first stirring include: a rotation speed of 1000-5000 rpm and a time of 0.5-3 min; the conditions for the second stirring include: a rotation speed of 60-120 rpm and a time of 30-60 min.

[0025] In this invention, the purpose of the first stirring is to disperse the phospholipid particles into particles of about 1 micrometer as much as possible. After the small particles combine with phosphate, they become charged particles, thus having an adsorption effect. The purpose of the second stirring is to allow the charged particles to adsorb cyclic peptides. At the same time, because the phospholipid particles carry the same type of charge, they generate repulsion between each other, and will not combine and grow larger during the stirring process, thus reducing the adsorption capacity.

[0026] In this invention, the debittered oil after the addition of acidic substances is not centrifuged, but directly deacidified. The soap formed during the deacidification process is used to encapsulate the phospholipid particles formed during the debittering process, thereby achieving the removal of phospholipids and cyclic peptides.

[0027] According to some embodiments of the present invention, in step (2), the deacidification method includes: mixing the debittered oil with an alkaline solution for a neutralization reaction, separating the solid and liquid phases, washing the resulting oil phase with water, and obtaining deacidified oil.

[0028] Preferably, the alkaline solution is selected from at least one of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, and sodium phosphate solution.

[0029] Preferably, the amount of alkali in the alkaline solution is calculated according to the formula shown in equation (II): (II); Among them, G 碱 G represents the total amount of alkali added to the alkaline solution, expressed in kg / 1kg of debittered oil; 碱，理 This represents the theoretical amount of alkali to be added to the alkaline solution, expressed in kg / 1 kg of debittered oil; G 碱，超 Excess alkali, unit is kg / 1kg debittered oil; C 碱 ΔV represents the mass fraction of the alkaline solution, in wt%; AV represents the acid value of the debittered oil, in mgKOH / g oil; G 油 The mass of debittered oil is expressed in kg.

[0030] In this invention, in order to completely remove acidic substances and free fatty acids from the debittered oil, preferably, the excess alkali (G... 碱，超 The amount of alkali added shall not exceed 20 wt% of the total amount of alkali added in the alkaline solution, that is, assuming that the total amount of alkali added in the alkaline solution relative to 1 kg of debittered oil is calculated according to the formula shown in equation (II), 碱 If the amount of alkali used is 0.5 kg, then the amount of excess alkali used is ≤ 0.1 kg.

[0031] In this invention, in formula (II), the mass fraction (C) of the alkaline solution is... 碱 The content is 6wt%-10wt%.

[0032] Preferably, the conditions for the neutralization reaction include: a temperature of 60-80°C and a time of 10-30 minutes.

[0033] Preferably, the amount of water used for washing is 3-8 wt% of the mass of the debittered oil; the washing conditions include: a temperature of 85-95℃ and a time of 10-20 min.

[0034] In this invention, preferably, the method further includes dehydrating the deacidified oil and then deodorizing it to obtain deodorized oil.

[0035] Preferably, the dehydration conditions are such that the water content in the dehydrated deacidified oil is not higher than 0.1 wt%.

[0036] Preferably, the deodorization conditions include: pressure ≤ 300 Pa; temperature 150-220 °C; and time 20-60 min.

[0037] More preferably, the deodorization conditions include: pressure ≤ 300 Pa; temperature 150-180 °C; and time 20-50 min.

[0038] In this invention, the deodorization conditions described herein enable the increase in trans fatty acids in the deodorized oil to be ≤0.03%. Furthermore, by applying the deodorization conditions described herein to treat crude flaxseed oil with a relatively low trans fatty acid content, flaxseed oil with a trans fatty acid content ≤0.3% (i.e., "zero trans" flaxseed oil) can be obtained.

[0039] In this invention, preferably, the method further includes dewaxing the deodorized oil.

[0040] Preferably, the dewaxing method includes: mixing the deodorized oil with a filter aid and settling at 4-8°C for 10-20 hours.

[0041] More preferably, the filter aid is selected from at least one of diatomaceous earth, perlite, and bentonite.

[0042] More preferably, the amount of the filter aid is 0.3-1 wt% of the mass of the degumming oil.

[0043] In this invention, the phosphorus content in crude flaxseed oil reflects the phospholipid content. Higher phosphorus content results in higher phospholipid content. Phospholipids and phosphoric acid form charged phospholipid particles during high-speed stirring, both of which have adsorption properties. If the phosphorus content is too low, the number of charged phospholipid particles will decrease, making it impossible to completely adsorb cyclic peptides. Conversely, if the phosphorus content is too high, the phospholipid particles will carry less charge, weakening the adsorption capacity and thus preventing complete adsorption of cyclic peptides. Preferably, the phosphorus content of the crude flaxseed oil is ≥60 ppm; more preferably, the phosphorus content is 60-600 ppm.

[0044] In this invention, if the phosphorus content in the crude flaxseed oil is too high, preferably, the method further includes degumming the crude flaxseed oil so that the phosphorus content of the crude flaxseed oil meets the above-mentioned limiting range.

[0045] More preferably, the degumming method includes: mixing the flaxseed oil with water for hydration degumming to obtain degummed oil.

[0046] More preferably, the conditions for hydration degumming include: the amount of water used is 1-2 wt% of the mass of the flaxseed oil; and the degumming temperature is 60-80℃.

[0047] In this invention, degumming and dewaxing are not necessary process steps and can be selected according to the quality of flaxseed oil or deodorized oil.

[0048] A second aspect of the present invention provides flaxseed oil prepared by the method of the present invention.

[0049] A third aspect of the present invention provides the application of the method described herein in removing bitter substances from flaxseed oil and improving the oxidative stability of flaxseed oil.

[0050] According to a particularly preferred embodiment of the present invention, a method for preparing flaxseed oil is provided, the method comprising the following steps: (1) Heat 1 kg of crude flaxseed oil (the phosphorus content of crude flaxseed oil is 350-400 ppm) to 60-70℃, add phosphoric acid solution to the crude oil, and mix the oil and phosphoric acid solution mixture (hereinafter referred to as the oil system) at a high speed of 3500-5000 rpm for 0.5-3 min. Then, keep the oil system at a stirring speed of 70-90 rpm for 30-45 min to obtain debittered oil. The amount of phosphoric acid used is calculated according to the formula shown in equation (I): C = a × A + b × B + c (I); C is the amount of acidic substance used, in mmol / 1kg flaxseed oil; a is the calculation coefficient; A is the total content of cyclic peptides in flaxseed oil, in mmol / 1kg flaxseed oil; b is the calculation coefficient; B is the total content of cyclic peptide P and cyclic peptide E in flaxseed oil, in mmol / 1kg flaxseed oil; c is a constant. The total content of cyclic peptides (denoted as A), the total content of cyclic peptide P and cyclic peptide E (denoted as B), 13.5≤a≤14, 15≤b≤15.5, -3≤c≤-1 in flaxseed oil were tested. The amount of phosphoric acid used (denoted as C) was calculated according to formula (I). In order to ensure complete removal of cyclic peptides, an additional 0.1-1.5wt% of excess phosphoric acid was added, which was converted into a phosphoric acid solution with a mass concentration of 75-85wt%. (2) Mix the debittered oil with sodium hydroxide solution and react at 76-80℃ for 10-15 min. After the reaction is completed, the soap foot is separated by centrifugation to obtain the oil phase. The oil phase is heated to 85-95℃, and 5-7wt% of the mass of the debittered oil is added to isothermal hot water. The mixture is washed with water for 15-20 min to obtain the deacidified oil. The amount of sodium hydroxide used in the sodium hydroxide solution is calculated according to the formula shown in equation (II). (II); Among them, G 碱 G represents the total amount of sodium hydroxide added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil. 碱，理 This represents the theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil; G 碱，超 Excess alkali, unit is kg / 1kg debittered oil; C 碱ΔV represents the mass fraction of sodium hydroxide solution, in wt%; AV represents the acid value of crude linseed oil, in mgKOH / g oil; G 油 The weight of crude flaxseed oil is expressed in kg / 1kg of debittered oil; G 碱，超 (Excess alkali) is set to G based on empirical values. 碱，理 1-8wt% (3) Heat the deacidified oil to 90-110℃ to dehydrate until the oil water content is less than 0.1wt%, then heat the oil to 155-175℃ and transfer it to the deodorization tower. Control the pressure of the deodorization tower to 150-200Pa and deodorize for 20-50 minutes to obtain deodorized oil. (4) Add 0.5-1wt% of diatomaceous earth to the deodorized oil, then cool it to 4-6℃ and keep it for 10-15 hours. After filtration, it is the finished oil.

[0051] The present invention will be described in detail below through embodiments.

[0052] The crude flaxseed oil 1 is produced in Kazakhstan, with an acid value of 2.10 mg KOH / g and a phosphorus content of 374.0 ppm.

[0053] Flaxseed crude oil 2 is produced in Canada, with an acid value of 1.83 mg KOH / g and a phosphorus content of 510.1 ppm.

[0054] Flaxseed crude oil 3 is produced in China, with an acid value of 2.22 mg KOH / g and a phosphorus content of 450.5 ppm.

[0055] Flaxseed crude oil 4 is produced in Kazakhstan, with an acid value of 1.16 mg KOH / g and a phosphorus content of 43.8 ppm.

[0056] The fitting method for equation (I) includes the following steps: (1) Obtain the total content of cyclic peptides, the total content of cyclic peptide P and cyclic peptide E in flaxseed oil from different origins; denot the total content of cyclic peptides in the flaxseed oil as A, and the total content of cyclic peptide P and cyclic peptide E as B; Cyclic peptides include cyclic peptides, cyclic peptide E, and cyclic peptide P. The content of cyclic peptides was determined according to the method described in the literature “Zeng Junpeng. Preparation of refined cold-pressed flaxseed oil rich in cyclic peptides and digestion and absorption of cyclic peptides [D]. Nanchang University, 2022. DOI: 10.27232 / d.cnki.gnchu.2022.004129”. (2) Flaxseed crude oil is mixed with acidic substances to remove bitterness, and debittered oil is obtained; the amount of acidic substances used is denoted as C; (3) Use linear regression to establish regression models for A, B, and C, and fit the formula (I) for the amount of acidic substances. C = a × A + b × B + c (I); C represents the amount of acidic substances used, in mmol / kg flaxseed oil; a is a calculation coefficient, with a value of 13.8; A represents the total content of cyclic peptides in flaxseed oil, in mmol / kg flaxseed oil; b is a calculation coefficient, with a value of 15.1; B represents the total content of cyclic peptide P and cyclic peptide E in flaxseed oil, in mmol / kg flaxseed oil; c is a constant, with a value of -3.

[0057] Example 1 (1) Heat 1 kg of flaxseed crude oil to 75°C, add phosphoric acid solution to the crude oil, and mix the oil and phosphoric acid solution mixture (hereinafter referred to as the oil system) at a high speed of 3000 rpm for 0.5 min. Then, keep the oil system at a stirring speed of 100 rpm for 50 min to obtain debittered oil. The total content of cyclic peptides in crude flaxseed oil 1 was found to be 0.57 mmol / 1 kg crude flaxseed oil (denoted as A), and the total content of cyclic peptides P and E was found to be 0.35 mmol / 1 kg crude flaxseed oil (denoted as B). The values ​​of a, b, and c were 13.8, 15.1, and -3, respectively. Based on formula (I), the required amount of phosphoric acid was calculated to be 10.17 mmol / 1 kg crude flaxseed oil (denoted as C). To ensure complete removal of cyclic peptides, an additional 5% excess phosphoric acid was added, resulting in an actual phosphoric acid dosage of 10.68 mmol / 1 kg crude flaxseed oil. After conversion, to obtain a phosphoric acid solution with a mass concentration of 85 wt%, the required mass of phosphoric acid solution to be added to crude flaxseed oil 1 was 0.123 wt% of crude flaxseed oil 1. (2) Mix the debittered oil with sodium hydroxide solution and react at 75°C for 20 min. After the reaction is completed, the soap foot is separated by centrifugation to obtain the oil phase. The oil phase is heated to 90°C, and isothermal hot water of 4 wt% of the debittered oil mass is added. The mixture is washed with water for 10 min to obtain the deacidified oil. The amount of sodium hydroxide used in the sodium hydroxide solution is calculated according to the formula shown in equation (II). (II); Among them, G 碱 G represents the total amount of sodium hydroxide added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil. 碱，理 This represents the theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil; G 碱，超 Excess alkali, unit is kg / 1kg debittered oil; C 碱 is the mass fraction of sodium hydroxide solution, in wt%; AV is the acid value of debittered flaxseed oil, in mgKOH / g oil; G 油 The mass of crude flaxseed oil is expressed in kg; calculated, G 碱，理The theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution is 1.93 g / 1 kg of debittered oil. 碱，超 (Excess alkali) is set to G based on empirical values. 碱，理 10wt%, G 碱 The total amount of sodium hydroxide added to the sodium hydroxide solution is 2.12 g / 1 kg of debittered oil. Converted to a 10 wt% sodium hydroxide solution, the amount of sodium hydroxide solution to be added to the debittered oil is 2.12 wt% of the oil's mass. (3) Heat the deacidified oil to 90°C and dehydrate it until the water content of the oil is less than 0.1wt%. Then heat the oil to 180°C and transfer it to the deodorization tower. Control the pressure of the deodorization tower to 200Pa and deodorize for 60 minutes to obtain deodorized oil. (4) Add 0.5 wt% of diatomaceous earth to the deodorized oil, then cool it down to 4°C and keep it for 10 hours. After filtration, it becomes the finished oil.

[0058] Example 2 (1) Heat 1 kg of crude flaxseed oil to 80°C, add phosphoric acid solution to the crude oil, and mix the oil and phosphoric acid solution mixture (hereinafter referred to as the oil system) at a high speed of 1000 rpm for 0.5 min. Then, keep the oil system at a stirring speed of 60 rpm for 60 min to obtain debittered oil. The total content of cyclic peptides in crude flaxseed oil 1 was found to be 0.57 mmol / 1 kg crude flaxseed oil (denoted as A), and the total content of cyclic peptides P and E was found to be 0.35 mmol / 1 kg crude flaxseed oil (denoted as B). The values ​​of a, b, and c were 13.8, 15.1, and -3, respectively. Based on formula (I), the required amount of phosphoric acid was calculated to be 10.17 mmol / 1 kg crude flaxseed oil (denoted as C). To ensure complete removal of cyclic peptides, an additional 2% excess phosphoric acid was added, meaning the actual amount of phosphoric acid used was 10.37 mmol / 1 kg crude flaxseed oil. After conversion, to obtain a 75 wt% phosphoric acid solution, the required mass of phosphoric acid solution to be added to crude flaxseed oil 1 was 0.136 wt% of crude flaxseed oil 1. (2) Mix the debittered oil with sodium hydroxide solution and react at 70°C for 15 min. After the reaction is completed, the soap foot is separated by centrifugation to obtain the oil phase. The oil phase is heated to 95°C, and isothermal hot water of 8 wt% of the debittered oil mass is added. The mixture is washed with water for 10 min to obtain the deacidified oil. The amount of sodium hydroxide used in the sodium hydroxide solution is calculated according to the formula shown in equation (II). (II); Among them, G 碱 G represents the total amount of sodium hydroxide added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil. 碱，理This represents the theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil; G 碱，超 Excess alkali, unit is kg / 1kg debittered oil; C 碱 ΔV represents the mass fraction of sodium hydroxide solution, in wt%; AV represents the acid value of crude linseed oil, in mgKOH / g oil; G 油 The mass of crude flaxseed oil is expressed in kg; calculated, G 碱，理 The theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution is 1.78 g / 1 kg of debittered oil. 碱，超 (Excess alkali) is set to G based on empirical values. 碱，理 20wt%, G 碱 The total amount of sodium hydroxide added to the sodium hydroxide solution is 2.14 g / 1 kg of debittered oil. Converted to an 8 wt% sodium hydroxide solution, the amount of sodium hydroxide solution to be added to the debittered oil is 2.68 wt% of the oil's mass. (3) Heat the deacidified oil to 110°C to dehydrate until the oil water content is less than 0.1wt%, then heat the oil to 210°C and transfer it to the deodorization tower. Control the pressure of the deodorization tower to 200Pa and deodorize for 30 minutes to obtain deodorized oil. (4) Add 0.5 wt% of diatomaceous earth to the deodorized oil, then cool it down to 4°C and keep it for 10 hours. After filtration, it becomes the finished oil.

[0059] Example 3 (1) Heat 1 kg of flaxseed crude oil to 70°C, add phosphoric acid solution to the crude oil, and mix the oil and phosphoric acid solution mixture (hereinafter referred to as the oil system) at a high speed of 5000 rpm for 0.5 min. Then, keep the oil system at a stirring speed of 80 rpm for 30 min to obtain debittered oil. The total content of cyclic peptides in crude flaxseed oil 1 was found to be 0.57 mmol / 1 kg crude flaxseed oil (denoted as A), and the total content of cyclic peptides P and E was found to be 0.35 mmol / 1 kg crude flaxseed oil (denoted as B). The values ​​of a, b, and c were 13.8, 15.1, and -3, respectively. Based on formula (I), the required amount of phosphoric acid was calculated to be 10.17 mmol / 1 kg crude flaxseed oil (denoted as C). To ensure complete removal of cyclic peptides, an additional 0.1% excess phosphoric acid was added, meaning the actual amount of phosphoric acid used was 10.17 mmol / 1 kg crude flaxseed oil. After conversion, to obtain a phosphoric acid solution with a mass concentration of 85 wt%, the required mass of phosphoric acid solution to be added to crude flaxseed oil 1 was 0.117 wt% of crude flaxseed oil 1. (2) Mix the debittered oil with sodium hydroxide solution and react at 80°C for 10 min. After the reaction is completed, the soap foot is separated by centrifugation to obtain the oil phase. The oil phase is heated to 85°C, and 6 wt% of the debittered oil mass of isothermal hot water is added. The mixture is washed with water for 15 min to obtain the deacidified oil. The amount of sodium hydroxide used in the sodium hydroxide solution is calculated according to the formula shown in equation (II). (II); Among them, G 碱 G represents the total amount of sodium hydroxide added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil. 碱，理 This represents the theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil; G 碱，超 Excess alkali, unit is kg / 1kg debittered oil; C 碱 ΔV represents the mass fraction of sodium hydroxide solution, in wt%; AV represents the acid value of crude linseed oil, in mgKOH / g oil; G 油 The weight of crude flaxseed oil is expressed in kg / 1kg of debittered oil; calculated, G 碱，理 The theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution is 2.03 g / 1 kg of debittered oil, G 碱，超 (Excess alkali) is set to G based on empirical values. 碱，理 5wt%, G 碱 The total amount of sodium hydroxide added to the sodium hydroxide solution is 2.13 g / 1 kg of debittered oil. Converted to a 6 wt% sodium hydroxide solution, the amount of sodium hydroxide solution to be added to the debittered oil is 3.55 wt% of the oil's mass. (3) Heat the deacidified oil to 100°C to dehydrate until the oil water content is less than 0.1wt%, then heat the oil to 170°C and transfer it to the deodorization tower. Control the pressure of the deodorization tower to 150Pa and deodorize for 20 minutes to obtain deodorized oil. (4) Add 0.5 wt% of diatomaceous earth to the deodorized oil, then cool it down to 4°C and keep it for 10 hours. After filtration, it becomes the finished oil.

[0060] Example 4 (1) Heat 1 kg of crude flaxseed oil to 75°C, add phosphoric acid solution to the crude oil, and mix the oil and phosphoric acid solution mixture (hereinafter referred to as the oil system) at a high speed of 3000 rpm for 0.5 min. Then, keep the oil system at a stirring speed of 100 rpm for 50 min to obtain debittered oil. The total content of cyclic peptides in flaxseed oil 2 was found to be 0.63 mmol / 1 kg flaxseed oil (denoted as A), and the total content of cyclic peptides P and E was found to be 0.27 mmol / 1 kg flaxseed oil (denoted as B). The values ​​for a were 13.8, b was 15.1, and c was -3. Based on formula (I), the required amount of phosphoric acid was calculated to be 9.79 mmol / 1 kg flaxseed oil (denoted as C). To ensure complete removal of cyclic peptides, an additional 2% excess phosphoric acid was added, resulting in an actual phosphoric acid dosage of 9.99 mmol / 1 kg flaxseed oil. After conversion, to obtain a phosphoric acid solution with a mass concentration of 85 wt%, the required mass of phosphoric acid solution to be added to flaxseed oil 1 was 0.115 wt% of that in flaxseed oil 2. (2) Mix the debittered oil with sodium hydroxide solution and react at 75°C for 20 min. After the reaction is completed, the soap foot is separated by centrifugation to obtain the oil phase. The oil phase is heated to 90°C, and isothermal hot water of 4 wt% of the debittered oil mass is added. The mixture is washed with water for 10 min to obtain the deacidified oil. The amount of sodium hydroxide used in the sodium hydroxide solution is calculated according to the formula shown in equation (II). (II); Among them, G 碱 G represents the total amount of sodium hydroxide added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil. 碱，理 This represents the theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil; G 碱，超 Excess alkali, unit is kg / 1kg debittered oil; C 碱 ΔV represents the mass fraction of sodium hydroxide solution, in wt%; AV represents the acid value of crude linseed oil, in mgKOH / g oil; G 油 The weight of crude flaxseed oil is expressed in kg / 1kg of debittered oil; calculated, G 碱，理 The theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution is 1.71 g / 1 kg of debittered oil. 碱，超 (Excess alkali) is set to G based on empirical values. 碱，理 10wt%, G 碱 The total amount of sodium hydroxide added to the sodium hydroxide solution is 1.88 g / 1 kg of debittered oil. Converted to a 10 wt% sodium hydroxide solution, the amount of sodium hydroxide solution to be added to the debittered oil is 1.88 wt% of the oil's mass. (3) Heat the deacidified oil to 90°C and dehydrate it until the water content of the oil is less than 0.1wt%. Then heat the oil to 200°C and transfer it to the deodorization tower. Control the pressure of the deodorization tower to 200Pa and deodorize for 60 minutes to obtain deodorized oil. (4) Add 0.5 wt% of diatomaceous earth to the deodorized oil, then cool it down to 4°C and keep it for 10 hours. After filtration, it becomes the finished oil.

[0061] Example 5 (1) Heat 1 kg of crude flaxseed oil to 75°C, add phosphoric acid solution to the crude oil, and mix the oil and phosphoric acid solution mixture (hereinafter referred to as the oil system) at a high speed of 3000 rpm for 0.5 min. Then, keep the oil system at a stirring speed of 100 rpm for 50 min to obtain debittered oil. The total content of cyclic peptides in crude flaxseed oil 3 was found to be 0.47 mmol / 1 kg crude flaxseed oil (denoted as A), and the total content of cyclic peptides P and E was found to be 0.18 mmol / 1 kg crude flaxseed oil (denoted as B). The values ​​for a were 13.8, b was 15.1, and c was -3. Based on formula (I), the required amount of phosphoric acid was calculated to be 6.22 mmol / 1 kg crude flaxseed oil (denoted as C). To ensure complete removal of cyclic peptides, an additional 5% excess phosphoric acid was added, resulting in an actual phosphoric acid dosage of 6.53 mmol / 1 kg crude flaxseed oil. After conversion, to obtain a phosphoric acid solution with a mass concentration of 85 wt%, the required mass of phosphoric acid solution to be added to crude flaxseed oil 1 was 0.075 wt% of crude flaxseed oil 3. (2) Mix the debittered oil with sodium hydroxide solution and react at 73°C for 15 min. After the reaction is completed, the soap foot is separated by centrifugation to obtain the oil phase. The oil phase is heated to 90°C, and isothermal hot water of 4 wt% of the debittered oil mass is added. The mixture is washed with water for 10 min to obtain the deacidified oil. The amount of sodium hydroxide used in the sodium hydroxide solution is calculated according to the formula shown in equation (II). (II); Among them, G 碱 G represents the total amount of sodium hydroxide added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil. 碱，理 This represents the theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution, expressed in kg / 1 kg of debittered oil; G 碱，超 Excess alkali, unit is kg / 1kg debittered oil; C 碱 ΔV represents the mass fraction of sodium hydroxide solution, in wt%; AV represents the acid value of crude linseed oil, in mgKOH / g oil; G 油 The mass of crude flaxseed oil is expressed in kg / 1kg of debittered oil; calculated, G 碱，理 The theoretical amount of sodium hydroxide to be added to the sodium hydroxide solution is 1.83 g / 1 kg of debittered oil. 碱，超 (Excess alkali) is set to G based on empirical values. 碱，理 10wt%, G 碱The total amount of sodium hydroxide added to the sodium hydroxide solution is 2.01 g / kg of debittered oil. Converted to a 10 wt% sodium hydroxide solution, the amount of sodium hydroxide solution to be added to the debittered oil is 2.01 wt% of the oil's mass. (3) Heat the deacidified oil to 90°C and dehydrate it until the water content of the oil is less than 0.1wt%. Then heat the oil to 200°C and transfer it to the deodorization tower. Control the pressure of the deodorization tower to 200Pa and deodorize for 60 minutes to obtain deodorized oil. (4) Add 0.5 wt% of diatomaceous earth to the deodorized oil, then cool it down to 4°C and keep it for 10 hours. After filtration, it becomes the finished oil.

[0062] Example 6 The method is the same as in Example 1, except that flaxseed oil 1 is replaced with flaxseed oil 4, while the other steps and process conditions are the same as in Example 1.

[0063] Example 7 The method of Example 1 is different in that, in step (1), the mixture of oil and phosphoric acid solution is mixed at 100 rpm for 0.5 min, and then the oil system is stirred at 3000 rpm for 50 min. Other steps and process conditions are the same as in Example 1.

[0064] Comparative Example 1 The method of Example 1 differs in that, in step (1), the cyclic peptide content of flaxseed oil 1 is not detected. Based on experience, the technician adds a phosphoric acid solution with a mass concentration of 85wt% to flaxseed oil 1 at a fixed ratio (refer to industry standard operation). The amount of phosphoric acid solution used is 0.05wt% of the mass of flaxseed oil 1. Other steps and process conditions are consistent with those of Example 1.

[0065] In Comparative Example 1, the amount of phosphoric acid solution used was not dynamically adjusted based on the content of cyclic peptides A and B in crude flaxseed oil 1. Following the method in Comparative Example 1, the actual amount of phosphoric acid used deviated from the amount calculated according to formula (I) by as much as 52.8%.

[0066] Comparative Example 2 The method of Example 4 differs in that, in step (1), the cyclic peptide content of flaxseed oil 2 is not detected. Based on experience, the technician adds a phosphoric acid solution with a mass concentration of 85wt% to flaxseed oil 2 at a fixed ratio (refer to industry standard operation). The amount of phosphoric acid solution used is 0.05wt% of the mass of flaxseed oil 2. Other steps and process conditions are consistent with those of Example 4.

[0067] In Comparative Example 2, the amount of phosphoric acid solution used was not dynamically adjusted based on the content of cyclic peptides A and B in crude flaxseed oil 2. Following the method in Comparative Example 2, the actual amount of phosphoric acid used deviated from the amount calculated according to formula (I) by as much as 51.9%.

[0068] Comparative Example 3 The method of Example 5 differs in that, in step (1), the cyclic peptide content of flaxseed oil 3 is not detected. Based on experience, the technician adds a phosphoric acid solution with a mass concentration of 85wt% to flaxseed oil 3 at a fixed ratio (refer to industry standard operation). The amount of phosphoric acid solution used is 0.05wt% of the mass of flaxseed oil 3. Other steps and process conditions are consistent with those of Example 5.

[0069] In Comparative Example 3, the amount of phosphoric acid solution used was not dynamically adjusted based on the content of cyclic peptides A and B in crude flaxseed oil 3. Following the method in Comparative Example 3, the actual amount of phosphoric acid used deviated from the amount calculated according to formula (I) by 33.3%.

[0070] Comparative Example 4 The method of Example 1 is different in that, in step (1), the technicians believe, based on experience, that the amount of phosphoric acid C is proportional to the total content A of cyclic peptides in flaxseed oil 1, and add it using the formula C=a×A (a is an empirical coefficient, which is 13.8 of Example 1). Other steps and process conditions are consistent with Example 1.

[0071] The total content of total cyclic peptides in flaxseed oil 1 was determined to be 0.57 mmol / 1 kg flaxseed oil (denoted as A). Following the method of Comparative Example 4, the calculated amount of phosphoric acid C was 7.87 mmol / 1 kg flaxseed oil. To ensure complete removal of cyclic peptides, an additional 5% excess phosphoric acid was added, resulting in an actual phosphoric acid dosage of 8.26 mmol / 1 kg flaxseed oil. Converted to an 85 wt% phosphoric acid solution, the required mass of phosphoric acid solution to be added to the flaxseed oil 1 was 0.095 wt%.

[0072] Comparative Example 5 The method of Example 1 differs in that: in step (1), the cyclic peptide content of flaxseed oil 1 is not detected; the technician adds a phosphoric acid solution with a mass concentration of 85wt% to flaxseed oil 1 according to experience and a fixed ratio (referring to industry standard operation), and the amount of phosphoric acid solution used is 0.05wt% of the mass of flaxseed oil 1; in step (3), the deacidified oil is first decolorized, and the decolorized oil is then deodorized. Specifically, the deacidified oil is heated to 100℃ and dehydrated until the water content of the oil is less than 0. After adding 0.1 wt% of the oil, heat the oil to 110°C and transfer it to a decolorizing tank. Add 1.5% (by weight) of activated clay to the deacidified oil and react at 80 rpm for 30 minutes. Filter to remove the activated clay to obtain decolorized oil. Heat the decolorized oil to 100°C to dehydrate until the oil water content is less than 0.1 wt%. Then heat the oil to 200°C and transfer it to a deodorizing tower. Control the pressure of the deodorizing tower at 150 Pa and deodorize for 20 minutes to obtain deodorized oil. Other steps and process conditions are the same as in Example 1.

[0073] Comparative Example 6 The method of Example 3 is different in that, in step (1), flaxseed crude oil 1 is mixed with activated clay, the amount of activated clay is 2wt% of crude oil, and after adsorption treatment at 105℃ for 30 min, centrifugation is performed to obtain debittered oil. Other steps and process conditions are consistent with those of Example 3.

[0074] Test case The content of cyclic peptides in crude flaxseed oil and finished flaxseed oil of the examples and comparative examples was determined, and the oxidation index of the finished flaxseed oil of the examples and comparative examples was determined. The specific data are shown in Table 1 and Table 2.

[0075] Cyclic peptides include cyclic peptides, cyclic peptide E, and cyclic peptide P. The content of cyclic peptides was determined according to the method described in the literature "Zeng Junpeng. Preparation of refined cold-pressed flaxseed oil rich in cyclic peptides and digestion and absorption of cyclic peptides [D]. Nanchang University, 2022. DOI: 10.27232 / d.cnki.gnchu.2022.004129".

[0076] Oxidation indicators include peroxide value, anisidine value, and oxidative stability. Peroxide value was determined according to the method specified in GB / T 5009.227-2016 National Food Safety Standard - Determination of Peroxide Value in Food; anisidine value was determined according to the method specified in GB / T 24304-2024 Animal and Vegetable Oils - Determination of Anisidine Value; and oxidative stability was determined according to the method specified in GB / T 21121-2024 Animal and Vegetable Oils - Determination of Oxidative Stability (Accelerated Oxidation Test). The peroxide value of the finished oil after 8 weeks of opening (opening test) was determined according to the method described in the literature "Huang Mingcui, et al. Study on oxidative rancidity of edible vegetable oil under household oil conditions [J]. China Oils and Fats, 2025, 50(4): 46-50.DOI: 10.19902 / j.cnki.zgyz. 1003-7969.240129", with slight modifications: After opening the 5 L package of flaxseed oil, 45 mL was poured out at 11:00 am and 5:00 pm each day. The oil was shaken well before each sampling, and the container was left open for 5 min after sampling. The oil sample in the 5 L container was stored under natural light and was completely removed on the 56th day. The peroxide value of the oil poured out on the last day was then tested.

[0077] Table 1

[0078] Note: Deviation value of phosphoric acid dosage = 100% × (actual amount of phosphoric acid added - amount of phosphoric acid calculated according to formula (I)) / (amount of phosphoric acid calculated according to formula (I)).

[0079] Table 2

[0080] Note: GB / T 2716-2018, the National Food Safety Standard for Vegetable Oils, requires that the peroxide value of crude vegetable oil and edible vegetable oil (including blended oil) be ≤0.25g / 100g, which translates to a peroxide value ≤9.85mmol / kg.

[0081] As can be seen from the results in Tables 1 and 2, the method of Examples 1-5 of this invention, without omitting the conventional decolorization process, can not only efficiently remove bitter peptides from flaxseed oil, but also improve the oxidative stability of refined flaxseed oil by more than 20%. Furthermore, the prepared oil has a low initial oxidation value, and after being left open for 8 weeks, the peroxide value of the finished oil is still ≤9.85 mmol / kg, meeting national standards and demonstrating stable quality. This solves the problem of existing technologies failing to simultaneously achieve debittering and oxidative stability in crude flaxseed oil. In addition, the method of this invention does not rely on the experience of technical personnel, allowing for rapid and accurate quantification of the amount of acidic substances added. This not only ensures the precision and controllability of the debittering process but also simplifies the operational threshold from the source, reducing reliance on the experience of skilled workers, thereby lowering personnel training costs and facilitating standardized operations in the industry.

[0082] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing flaxseed oil, characterized in that, The method includes the following steps: (1) Determine the content of cyclic peptides in crude flaxseed oil, calculate the amount of acidic substance according to formula (I), mix crude flaxseed oil with acidic substance to debitter, and obtain debittered oil. C = a × A + b × B + c (I); C represents the amount of acidic substances used, in mmol / kg flaxseed oil; a is a calculation coefficient, 12≤a≤20; A represents the total content of cyclic peptides in flaxseed oil, in mmol / kg flaxseed oil; b is a calculation coefficient, 9≤b≤16; B represents the total content of cyclic peptide P and cyclic peptide E in flaxseed oil, in mmol / kg flaxseed oil; c is a constant, -15≤c≤0. (2) Deacidify the debittered oil to obtain deacidified oil.

2. The method according to claim 1, wherein, In step (1), the acidic substance is selected from at least one of phosphoric acid, citric acid, lactic acid, hydrochloric acid, and sulfuric acid; Preferably, in step (1), the debittering conditions include: a temperature of 55℃-80℃ and a time of 30-65min; Preferably, the phosphorus content of the crude flaxseed oil is ≥60ppm.

3. The method according to claim 2, wherein, The debittering method includes: mixing flaxseed crude oil with an acidic substance under conditions of 55℃-80℃ and then performing a first stirring and a second stirring. Preferably, the conditions for the first stirring include: a rotation speed of 1000-5000 rpm and a time of 0.5-5 min; the conditions for the second stirring include: a rotation speed of 60-120 rpm and a time of 29.5-60 min.

4. The method according to any one of claims 1-3, wherein, In step (2), the deacidification method includes: mixing the debittered oil with an alkaline solution for neutralization reaction, solid-liquid separation, washing the obtained oil phase with water to obtain deacidified oil; Preferably, the alkaline solution is selected from at least one of sodium hydroxide solution, potassium hydroxide solution, sodium carbonate solution, and sodium phosphate solution; Preferably, the conditions for the neutralization reaction include: a temperature of 60-80°C and a time of 10-20 minutes; Preferably, the amount of water used for washing is 3-8 wt% of the mass of the debittered oil; the washing conditions include: a temperature of 85-95℃ and a time of 10-20 min.

5. The method according to claim 4, wherein, The method further includes dehydrating the deacidified oil and then deodorizing it to obtain deodorized oil; Preferably, the dehydration conditions are such that the water content in the dehydrated deacidified oil is not higher than 0.1 wt%. Preferably, the deodorization conditions include: pressure ≤ 300 Pa; temperature 150-220 °C; and time 20-60 min.

6. The method according to claim 5, wherein, The method further includes dewaxing the deodorized oil; The dewaxing method includes mixing the deodorized oil with a filter aid and settling it at 4-8°C for 10-20 hours.

7. The method according to claim 6, wherein, The filter aid is selected from at least one of diatomaceous earth, perlite and bentonite; Preferably, the amount of the filter aid is 0.3-1 wt% of the mass of the deodorized oil.

8. The method according to any one of claims 1-7, wherein the method further comprises degumming the crude flaxseed oil; Preferably, the degumming method includes: The crude flaxseed oil is mixed with water and degummed to obtain degummed oil. More preferably, the conditions for hydration degumming include: the amount of water used is 1-2 wt% of the mass of the crude flaxseed oil; The degumming temperature is 60-80℃.

9. Flaxseed oil prepared by the method according to any one of claims 1-8.

10. The application of the method according to any one of claims 1-8 in removing bitter substances from flaxseed oil and improving the oxidative stability of flaxseed oil.

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