Method for removing volatile fishy smell components in linseed oil

Abstract

The invention discloses a method for removing volatile fishy smell components in linseed oil, and relates to the technical field of linseed oil preparation. The method specifically comprises the following steps: carrying out degumming pretreatment on flaxseeds, carrying out ultrasonic treatment, then carrying out supercritical extraction to obtain crude refined flaxseed oil, adding a deacidification agent, and carrying out water bath stirring centrifugation to obtain deacidified flaxseed oil; adding a composite adsorbent, stirring and centrifuging to obtain decolorized linseed oil; adding green tea polyphenol, continuously stirring and centrifuging, finally adding a flavor stabilizer, and uniformly stirring to obtain the refined linseed oil without volatile fishy smell. Wherein the green tea polyphenol and the composite adsorbent have a synergistic effect, so that a good deodorization effect is brought to the linseed oil.

Description

Technical Field

[0001] The invention relates to the technical field of linseed oil preparation, in particular to a method for removing volatile fishy smell components in linseed oil. Background Art

[0002] Fresh linseed oil is golden in color, mild in smell, and has a pleasant nutty flavor. However, for various reasons, commercially available linseed oil will have a strong, unpleasant odor. This odor is different from the smell of ordinary oils and has a stronger "green or fishy" component. The so-called "original" linseed oil is difficult for high-end consumers to accept.

[0003] Flax oil is rich in the functional ingredient α-linolenic acid. Its high degree of unsaturation makes it impossible to use the high-temperature refining process of traditional oils. High-temperature deodorization can remove free fatty acids and unstable small molecular fishy components, but it is easy to cause α-linolenic acid to oxidize and deteriorate, solidify and polymerize, resulting in a decrease in nutritional value and even the production of trans fatty acids that are harmful to the human body. The constraints of the refining process make it difficult to solve the problem of deodorization of flax oil.

[0004] According to previous research results, the fishy smell components in the volatile components of linseed oil may be related to alcohols, aldehydes, ketones and other small molecular compounds containing nitrogen, phosphorus, sulfur, etc. produced by the oxidation and deterioration of polyunsaturated fatty acids or proteins. Therefore, in order to effectively remove the fishy smell components while maintaining the quality of linseed oil, the present invention studies a method for removing volatile fishy smell components in linseed oil based on the processing of raw materials. Summary of the invention

[0005] The purpose of the present invention is to provide a method for removing volatile fishy smell components in linseed oil to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for removing volatile fishy smell components in linseed oil comprises the following steps:

[0008] Step 1: After pretreatment of flaxseed degumming, ultrasonic treatment is performed for 20-30 minutes and then supercritical extraction is performed for 2-3 hours to obtain crude flaxseed oil, a deacidifying agent is added, and the mixture is stirred in a water bath at 60-70° C. for 20-30 minutes, and centrifuged to obtain deacidified flaxseed oil;

[0009] Step 2: add green tea polyphenols to the deacidified linseed oil prepared in step 1, stir at 60°C for 20-30 minutes, and centrifuge to obtain decolorized linseed oil;

[0010] Step 3: Take the decolorized linseed oil prepared in step 2, add a deodorizing agent, shake at 60°C for 20-30 minutes, cool and centrifuge at high speed, then add a flavor stabilizer and stir evenly;

[0011] Furthermore, the specific steps of the degumming pretreatment in step 1 include: separating the flaxseed from the shell and kernel, crushing and sieving the separated flaxseed kernel, dissolving it in deionized water, adding pectinase for enzymolysis at 32-38° C. for 3 hours, and freeze-drying after centrifugation.

[0012] In step 1, the supercritical extraction is set at a CO2 flow rate of 20-30 kg / h, an extraction temperature of 40° C., and an extraction pressure of 3-5 MPa.

[0013] The preparation steps of the deacidifying agent in step 1 include: stirring diatomaceous earth mixed with alkali solution at 60° C. for 1-2 hours, filtering and crushing, and drying for later use; wherein the solid-to-liquid ratio of diatomaceous earth to alkali solution is 1:(4-5).

[0014] Furthermore, in step 2, the composite adsorbent includes alkaline activated clay and activated carbon, wherein the activated carbon comes from the heat treatment carbonization of flax seed straw, and the specific steps include: immersing the flax seed straw in a zinc chloride solution with a concentration of 25g:1L for 2-3h, drying at 80°C and then heat treating, heating to 600°C under an argon gas flow, keeping warm for 1h, grinding evenly after cooling, fully pickling with sulfuric acid and then washing with deionized water to neutrality, and drying to obtain activated carbon.

[0015] The preparation steps of the alkalized activated clay include: mixing the activated clay with alkali solution, adjusting the pH value to 7.4-8.9, filtering, drying, crushing and sieving to obtain the alkalized activated clay.

[0016] Furthermore, the flavor stabilizer in step 3 comprises the following raw materials in parts by mass: 20-30 parts of plant essential oil, 40-50 parts of modified lignans, 0.5-1.0 parts of tert-butylhydroquinone, 0.2-0.3 parts of butylated hydroxyanisole and 5-8 parts of vitamin E.

[0017] In step 3, the plant essential oil is one or more combinations of grapefruit peel essential oil, clove basil essential oil, and lemongrass essential oil.

[0018] The preparation steps of the modified lignan include: separating the flaxseed from the flaxseed in step 1 from the hull to the kernel, ball-milling the separated flaxseed hull for 3-5 hours, adding an ethanol solution, stirring for 1 hour at 4°C in the dark, performing supercritical extraction, setting the pressure to 9MPa, extracting for 30 minutes at 35°C, taking out and centrifuging for 5 minutes at 5000r / min, collecting the supernatant, performing alkaline hydrolysis for 20 minutes, adjusting to neutrality, and performing high-speed centrifugation to obtain purified lignan, adding lauroyl chloride and methanesulfonic acid to the mixture, stirring in a water bath at 40°C for 2 hours, adding ice water after cooling, vacuum filtering, washing, and freeze-drying to obtain the modified lignan.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The composite adsorbent added in the present invention is not only activated clay, which has good adsorption properties, but the linseed oil after treatment will have obvious odor. Therefore, activated clay is alkalized and activated carbon is compounded at the same time. The activated carbon is derived from linseed straw and is obtained by heat treatment and carbonization. On the one hand, it solves the problem of processing straw after harvesting linseed. On the other hand, the internal loose porous structure of the activated carbon also brings good adsorption effect.

[0021] 2. The deodorization process of the present invention uses activated carbon, alkalized activated clay and green tea polyphenols in two steps, and the deodorization effect is the best;

[0022] 3. The present invention adds a flavor stabilizer, such as grapefruit peel essential oil, into flaxseed oil, which has a strong and fragrant flavor and a strong antioxidant activity. It can mask the odor of flaxseed oil and improve the antioxidant activity of the oil system. The modified lignans are obtained by separating flaxseed hulls from flaxseed hulls, crushing them, and then supercritically extracting and purifying the lignans. The application of lignans in the oil system is improved by modification, the fat solubility is expanded, and good oxidation stability is brought to flaxseed oil. DETAILED DESCRIPTION

[0023] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without making any creative work shall fall within the scope of protection of the present invention.

[0024] In the experiment, flax seeds were provided by Datong Chengzhi Company and Ningwu Ruixinyu Agricultural Products Processing Professional Cooperative; pectinase with item number S10007 and green tea polyphenols with item number S18152 were purchased from Shanghai Yuanye Biotechnology Co., Ltd.; activated white clay was purchased from Lingshou County Yongshun Mineral Products Processing Plant;

[0025] Embodiment 1: This embodiment provides a method for removing volatile odor components in linseed oil, comprising the following steps:

[0026] Step 1: Separate the flaxseed from the shell and kernel, grind the separated flaxseed kernel through an 80-mesh sieve, dissolve it in deionized water at a solid-liquid ratio of 1g:20ml, add 1000U / g pectinase for enzymolysis at 34°C for 3h, centrifuge and freeze-dry to obtain degummed flaxseed, perform ultrasonic treatment for 20min and then perform supercritical extraction, set the CO2 flow rate to 25kg / h, the extraction temperature to 40°C, the extraction pressure to 3MPa, perform ultrasonic extraction for 2h to obtain crude flaxseed oil, add a deacidifying agent of 1% by weight of the oil, stir in a water bath at 60°C for 30min, and centrifuge to obtain deacidified flaxseed oil; wherein the step of the deacidifying agent comprises: mixing diatomaceous earth with 20% sodium hydroxide solution, stirring at 60°C for 1h, filtering and grinding, and drying for standby use; wherein the solid-liquid ratio of diatomaceous earth to 20% sodium hydroxide solution is 1:5.

[0027] Step 2: add 2% of the weight of the composite adsorbent to the deacidified linseed oil obtained in step 1, stir at 60° C. for 20 min, and centrifuge to obtain decolorized linseed oil;

[0028] The composite adsorbent comprises alkaline activated clay and activated carbon in a mass ratio of 2:1, wherein the activated carbon comes from the heat treatment carbonization of flax seed straw, and the specific steps include: immersing the flax seed straw in a 10% zinc chloride solution for 2 hours, with a solid-liquid ratio of 25g:1L, drying at 80°C and then heat treating, heating to 600°C under an argon gas flow, keeping warm for 1 hour, grinding evenly after cooling, fully pickling with 20% sulfuric acid and then washing with deionized water to neutrality, and drying to obtain activated carbon; the preparation steps of the alkaline activated clay include: mixing the activated clay with a 20% sodium hydroxide solution, adjusting to a pH of 7.9, filtering, drying, crushing, and sieving to obtain the alkaline activated clay.

[0029] Step 3: Take the decolorized linseed oil prepared in step 2, add 1% of green tea polyphenols by weight of the oil, shake at 60° C. for 30 minutes, centrifuge at 10,000 r / min after cooling, then add 1% of flavor stabilizer by weight of the oil, and stir evenly;

[0030] The flavor stabilizer includes the following raw materials in parts by weight: 30 parts of grapefruit peel essential oil, 50 parts of modified lignans, 0.5 parts of tert-butylhydroquinone, 0.2 parts of butylated hydroxyanisole and 5 parts of vitamin E;

[0031] The preparation steps of the modified lignan include: ball-milling the flaxseed hull separated from the flaxseed hull kernel in step 1 for 3 hours, adding an ethanol solution with a solid-liquid ratio of 1:5, stirring at 4°C in the dark for 1 hour, performing supercritical extraction, setting the pressure to 9MPa, extracting at 35°C for 30 minutes, taking out and centrifuging at 5000r / min for 5 minutes, collecting the supernatant, performing alkaline hydrolysis for 20 minutes, adjusting to neutrality, and high-speed centrifugation to obtain purified lignan, freeze-drying, taking 1.5g of the purified lignan, adding 4g of lauroyl chloride and 5ml of methane sulfonic acid to mix, stirring in a water bath at 40°C for 2 hours, adding ice water after cooling, vacuum filtering, washing and freeze-drying to obtain the modified lignan.

[0032] Embodiment 2: This embodiment provides a method for removing volatile fishy smell components in linseed oil, comprising the following steps:

[0033] Step 1: Separate the flaxseed from the shell and kernel, grind the separated flaxseed kernel through an 80-mesh sieve, dissolve it in deionized water at a solid-liquid ratio of 1g:20ml, add 1000U / g pectinase for enzymolysis at 34°C for 3h, centrifuge and freeze-dry to obtain degummed flaxseed, perform ultrasonic treatment for 30min and then perform supercritical extraction, set the CO2 flow rate to 25kg / h, the extraction temperature to 40°C, the extraction pressure to 3MPa, perform ultrasonic extraction for 3h to obtain crude flaxseed oil, add a deacidifying agent with a weight of 1% of the oil, stir in a water bath at 60°C for 30min, and centrifuge to obtain deacidified flaxseed oil; wherein the step of the deacidifying agent comprises: mixing diatomaceous earth with a 20% sodium hydroxide solution and stirring at 60°C for 1h, filtering and crushing, and drying for standby use; wherein the solid-liquid ratio of diatomaceous earth to 20% sodium hydroxide solution is 1:5.

[0034] Step 2: add 2% of the weight of the composite adsorbent to the deacidified linseed oil obtained in step 1, stir at 60°C for 25 minutes, and centrifuge to obtain the decolorized linseed oil; the composite adsorbent comprises alkaline activated clay and activated carbon in a mass ratio of 1:1, wherein the activated carbon comes from the heat treatment carbonization of linseed straw, and the specific steps include: immersing the linseed straw in a 10% zinc chloride solution for 3 hours, with a solid-liquid ratio of 25g:1L, drying at 80°C and then heat treating, heating to 600°C under an argon gas flow, keeping the temperature for 1 hour, grinding evenly after cooling, fully pickling with 20% sulfuric acid, washing with deionized water to neutrality, and drying to obtain the activated carbon.

[0035] The preparation steps of the alkaline activated clay include: mixing the activated clay with a 20% sodium hydroxide solution, adjusting the pH value to 7.9, filtering, drying, crushing, and sieving to obtain the alkaline activated clay.

[0036] Step 3: Take the decolorized linseed oil prepared in step 2, add 1% of green tea polyphenols by weight of the oil, shake at 60° C. for 30 minutes, centrifuge at 10,000 r / min after cooling, then add 1% of flavor stabilizer by weight of the oil, and stir evenly;

[0037] The flavor stabilizer includes the following raw materials in parts by weight: 30 parts of grapefruit peel essential oil, 50 parts of modified lignans, 0.5 parts of tert-butylhydroquinone, 0.2 parts of butylated hydroxyanisole and 5 parts of vitamin E;

[0038] The preparation steps of the modified lignan include: ball-milling the flaxseed hull separated from the flaxseed hull kernel in step 1 for 4 hours, adding an ethanol solution with a solid-liquid ratio of 1:5, stirring for 1 hour in the dark at 4°C, performing supercritical extraction, setting the pressure to 9MPa, extracting for 30 minutes at 35°C, taking out and centrifuging at 5000r / min for 5 minutes, collecting the supernatant, performing alkaline hydrolysis for 20 minutes, adjusting to neutrality, and high-speed centrifugation to obtain purified lignan, freeze-drying, taking 1.5g of the purified lignan, adding 4g of lauroyl chloride and 5ml of methane sulfonic acid to mix, stirring in a water bath at 40°C for 2 hours, adding ice water after cooling, vacuum filtering, washing and freeze-drying to obtain the modified lignan.

[0039] Embodiment 3: This embodiment provides a method for removing volatile odor components in linseed oil, comprising the following steps:

[0040] Step 1: separating the flaxseed from the shell and kernel, crushing the separated flaxseed kernel through an 80-mesh sieve, dissolving it in deionized water at a solid-liquid ratio of 1g:20ml, adding 1000U / g pectinase for enzymolysis at 34°C for 3h, centrifuging and freeze-drying to obtain degummed flaxseed, ultrasonically treating for 30min and then supercritical extraction, setting the CO2 flow rate to 25kg / h, the extraction temperature to 40°C, the extraction pressure to 3MPa, ultrasonic extraction for 3h to obtain crude flaxseed oil, adding a deacidifying agent of 1% by weight of the oil, stirring in a water bath at 60°C for 30min, and centrifuging to obtain deacidified flaxseed oil; the step of the deacidifying agent comprises: mixing diatomaceous earth with 20% sodium hydroxide solution, stirring at 60°C for 2h, filtering and crushing, and drying for standby use; wherein the solid-liquid ratio of diatomaceous earth to 20% sodium hydroxide solution is 1:5.

[0041] Step 2: add 2% of the weight of the composite adsorbent to the deacidified linseed oil prepared in step 1, stir at 60° C. for 30 min, and centrifuge to obtain decolorized linseed oil;

[0042] The composite adsorbent includes alkaline activated clay and activated carbon in a mass ratio of 1:1, wherein the activated carbon comes from the heat treatment carbonization of flax seed straw, and the specific steps include: immersing the flax seed straw in a 10% zinc chloride solution for 3 hours, with a solid-liquid ratio of 25g:1L, drying at 80°C and then heat treating, heating to 600°C under an argon gas flow, keeping the temperature for 1 hour, grinding evenly after cooling, fully pickling with 20% sulfuric acid and then washing with deionized water to neutrality, and drying to obtain activated carbon.

[0043] The preparation steps of the alkaline activated clay include: mixing the activated clay with a 20% sodium hydroxide solution, adjusting the pH value to 7.9, filtering, drying, crushing, and sieving to obtain the alkaline activated clay.

[0044] Step 3: Take the decolorized linseed oil prepared in step 2, add 1% of green tea polyphenols by weight of the oil, shake at 60° C. for 30 minutes, centrifuge at 10,000 r / min after cooling, then add 1.5% of flavor stabilizer by weight of the oil, and stir evenly;

[0045] The flavor stabilizer includes the following raw materials in parts by weight: 30 parts of grapefruit peel essential oil, 50 parts of modified lignans, 0.5 parts of tert-butylhydroquinone, 0.2 parts of butylated hydroxyanisole and 5 parts of vitamin E;

[0046] The preparation steps of the modified lignan include: ball-milling the flaxseed hull separated from the flaxseed hull kernel in step 1 for 5 hours, adding an ethanol solution with a solid-liquid ratio of 1:5, stirring at 4°C in the dark for 1 hour, performing supercritical extraction, setting the pressure to 9MPa, extracting at 35°C for 30 minutes, taking out and centrifuging at 5000r / min for 5 minutes, collecting the supernatant, performing alkaline hydrolysis for 20 minutes, adjusting to neutrality, and high-speed centrifugation to obtain purified lignan, freeze-drying, taking 1.5g of the purified lignan, adding 4g of lauroyl chloride and 5ml of methane sulfonic acid to mix, stirring in a water bath at 40°C for 2 hours, adding ice water after cooling, vacuum filtering, washing and freeze-drying to obtain the modified lignan.

[0047] Embodiment 4: This embodiment provides a method for removing volatile fishy smell components in linseed oil, comprising the following steps:

[0048] Step 1: Separate the flaxseed from the shell and kernel, grind the separated flaxseed kernel through an 80-mesh sieve, dissolve in deionized water at a solid-liquid ratio of 1 g:20 ml, add 1000 U / g pectinase for enzymolysis at 34°C for 3 hours, centrifuge and freeze-dry to obtain degummed flaxseed, perform ultrasonic treatment for 30 minutes and then perform supercritical extraction, set the CO2 flow rate to 25 kg / h, the extraction temperature to 40°C, the extraction pressure to 3 MPa, perform ultrasonic extraction for 3 hours to obtain crude flaxseed oil, add a deacidifying agent of 1% by weight of the oil, stir in a water bath at 60°C for 30 minutes, and centrifuge to obtain deacidified flaxseed oil;

[0049] The step of using a deacidifying agent comprises: mixing diatomaceous earth with a 20% sodium hydroxide solution at 60° C. and stirring for 2 hours, filtering and crushing, and drying for later use; wherein the solid-to-liquid ratio of the diatomaceous earth to the 20% sodium hydroxide solution is 1:5.

[0050] Step 2: add 2% of the weight of the composite adsorbent to the deacidified linseed oil prepared in step 1, stir at 60° C. for 30 min, and centrifuge to obtain decolorized linseed oil;

[0051] The composite adsorbent includes alkaline activated clay and activated carbon, wherein the activated carbon comes from the heat treatment carbonization of flax seed straw, and the specific steps include: immersing the flax seed straw in a 10% zinc chloride solution for 3 hours, with a solid-liquid ratio of 25g:1L, drying at 80°C and then heat treating, heating to 600°C under an argon gas flow, keeping warm for 1 hour, grinding evenly after cooling, fully pickling with 20% sulfuric acid and then washing with deionized water to neutrality, and drying to obtain activated carbon.

[0052] The preparation steps of the alkaline activated clay include: mixing the activated clay with a 20% sodium hydroxide solution, adjusting the pH value to 7.9, filtering, drying, crushing, and sieving to obtain the alkaline activated clay.

[0053] Step 3: Take the decolorized linseed oil prepared in step 2, add 1% of green tea polyphenols by weight of the oil, shake at 60° C. for 30 minutes, centrifuge at 10,000 r / min after cooling, then add 2% of the flavor stabilizer by weight of the oil, and stir evenly;

[0054] The flavor stabilizer includes the following raw materials in parts by weight: 30 parts of grapefruit peel essential oil, 50 parts of modified lignans, 0.5 parts of tert-butylhydroquinone, 0.2 parts of butylated hydroxyanisole and 5 parts of vitamin E;

[0055] The preparation steps of the modified lignan include: ball-milling the flaxseed hull separated from the flaxseed hull kernel in step 1 for 5 hours, adding an ethanol solution with a solid-liquid ratio of 1:5, stirring at 4°C in the dark for 1 hour, performing supercritical extraction, setting the pressure to 9MPa, extracting at 35°C for 30 minutes, taking out and centrifuging at 5000r / min for 5 minutes, collecting the supernatant, performing alkaline hydrolysis for 20 minutes, adjusting to neutrality, and high-speed centrifugation to obtain purified lignan, freeze-drying, taking 1.5g of the purified lignan, adding 4g of lauroyl chloride and 5ml of methane sulfonic acid to mix, stirring in a water bath at 40°C for 2 hours, adding ice water after cooling, vacuum filtering, washing and freeze-drying to obtain the modified lignan.

[0056] Comparative Example 1: With respect to Example 4, the composite adsorbent is adjusted to alkaline activated clay, and the specific steps are as follows:

[0057] Step 1: Separate the flaxseed from the shell and kernel, grind the separated flaxseed kernel through an 80-mesh sieve, dissolve in deionized water at a solid-liquid ratio of 1 g:20 ml, add 1000 U / g pectinase for enzymolysis at 34°C for 3 hours, centrifuge and freeze-dry to obtain degummed flaxseed, perform ultrasonic treatment for 30 minutes and then perform supercritical extraction, set the CO2 flow rate to 25 kg / h, the extraction temperature to 40°C, the extraction pressure to 3 MPa, perform ultrasonic extraction for 3 hours to obtain crude flaxseed oil, add a deacidifying agent of 1% by weight of the oil, stir in a water bath at 60°C for 30 minutes, and centrifuge to obtain deacidified flaxseed oil;

[0058] The step of using a deacidifying agent comprises: mixing diatomaceous earth with a 20% sodium hydroxide solution at 60° C. and stirring for 2 hours, filtering and crushing, and drying for later use; wherein the solid-to-liquid ratio of the diatomaceous earth to the 20% sodium hydroxide solution is 1:5.

[0059] Step 2: add 2% of the weight of the oil to the deacidified linseed oil obtained in step 1, alkalized activated clay, stir at 60° C. for 30 min, and centrifuge to obtain decolorized linseed oil;

[0060] The preparation steps of the alkaline activated clay include: mixing the activated clay with a 20% sodium hydroxide solution, adjusting the pH value to 7.9, filtering, drying, crushing, and sieving to obtain the alkaline activated clay.

[0061] Step 3: Take the decolorized linseed oil prepared in step 2, add 1% of green tea polyphenols by weight of the oil, shake at 60° C. for 30 minutes, centrifuge at 10,000 r / min after cooling, then add 2% of the flavor stabilizer by weight of the oil, and stir evenly;

[0062] The flavor stabilizer includes the following raw materials in parts by weight: 30 parts of grapefruit peel essential oil, 50 parts of modified lignans, 0.5 parts of tert-butylhydroquinone, 0.2 parts of butylated hydroxyanisole and 5 parts of vitamin E;

[0063] The preparation steps of the modified lignan include: ball-milling the flaxseed hull separated from the flaxseed hull kernel in step 1 for 5 hours, adding an ethanol solution with a solid-liquid ratio of 1:5, stirring at 4°C in the dark for 1 hour, performing supercritical extraction, setting the pressure to 9MPa, extracting at 35°C for 30 minutes, taking out and centrifuging at 5000r / min for 5 minutes, collecting the supernatant, performing alkaline hydrolysis for 20 minutes, adjusting to neutrality, and high-speed centrifugation to obtain purified lignan, freeze-drying, taking 1.5g of the purified lignan, adding 4g of lauroyl chloride and 5ml of methane sulfonic acid to mix, stirring in a water bath at 40°C for 2 hours, adding ice water after cooling, vacuum filtering, washing and freeze-drying to obtain the modified lignan.

[0064] Comparative Example 2: The lignan in Example 4 was not modified, and specifically included the following steps:

[0065] Step 1: Separate the flaxseed from the shell and kernel, grind the separated flaxseed kernel through an 80-mesh sieve, dissolve in deionized water at a solid-liquid ratio of 1 g:20 ml, add 1000 U / g pectinase for enzymolysis at 34°C for 3 hours, centrifuge and freeze-dry to obtain degummed flaxseed, perform ultrasonic treatment for 30 minutes and then perform supercritical extraction, set the CO2 flow rate to 25 kg / h, the extraction temperature to 40°C, the extraction pressure to 3 MPa, perform ultrasonic extraction for 3 hours to obtain crude flaxseed oil, add a deacidifying agent of 1% by weight of the oil, stir in a water bath at 60°C for 30 minutes, and centrifuge to obtain deacidified flaxseed oil;

[0066] The step of using a deacidifying agent comprises: mixing diatomaceous earth with a 20% sodium hydroxide solution at 60° C. and stirring for 2 hours, filtering and crushing, and drying for later use; wherein the solid-to-liquid ratio of the diatomaceous earth to the 20% sodium hydroxide solution is 1:5.

[0067] Step 2: add 2% of the weight of the composite adsorbent to the deacidified linseed oil prepared in step 1, stir at 60° C. for 30 min, and centrifuge to obtain decolorized linseed oil;

[0068] The composite adsorbent includes alkaline activated clay and activated carbon, wherein the activated carbon comes from the heat treatment carbonization of flax seed straw, and the specific steps include: immersing the flax seed straw in a 10% zinc chloride solution for 3 hours, with a solid-liquid ratio of 25g:1L, drying at 80°C and then heat treating, heating to 600°C under an argon gas flow, keeping warm for 1 hour, grinding evenly after cooling, fully pickling with 20% sulfuric acid and then washing with deionized water to neutrality, and drying to obtain activated carbon.

[0069] The preparation steps of the alkaline activated clay include: mixing the activated clay with a 20% sodium hydroxide solution, adjusting the pH value to 7.9, filtering, drying, crushing, and sieving to obtain the alkaline activated clay.

[0070] Step 3: Take the decolorized linseed oil prepared in step 2, add 1% of green tea polyphenols by weight of the oil, shake at 60° C. for 30 minutes, centrifuge at 10,000 r / min after cooling, then add 2% of the flavor stabilizer by weight of the oil, and stir evenly;

[0071] The flavor stabilizer comprises the following raw materials in parts by weight: 30 parts of grapefruit peel essential oil, 50 parts of lignans, 0.5 parts of tert-butylhydroquinone, 0.2 parts of butylated hydroxyanisole and 5 parts of vitamin E; the preparation steps of the lignans comprise: ball-milling the flaxseed hull separated from the flaxseed hull kernel in step 1 for 5 hours, adding an ethanol solution with a solid-liquid ratio of 1:5, stirring at 4°C in the dark for 1 hour, performing supercritical extraction, setting the pressure to 9MPa, extracting at 35°C for 30 minutes, taking out and centrifuging at 5000r / min for 5 minutes, collecting the supernatant, performing alkaline hydrolysis for 20 minutes, adjusting to neutrality, high-speed centrifugation, and freeze-drying to obtain purified lignans.

[0072] Detection test

[0073] 1. The main volatile components of linseed oil were determined by HS-SPME-GC-MS results according to the NIST mass spectrum database combined with the LUG database combined with relevant literature data and the ROAV value method. The main volatile components of linseed oil are aldehydes, alcohols, esters, furans, etc. The changes in the relative content % of the main volatile odor components in the linseed oil prepared in Examples 1-4 and Comparative Examples 1-2 are shown in Table 1.

[0074] 2. The physical and chemical properties of the linseed oils prepared in Examples 1-4 and Comparative Examples 1-2 were tested, including color, odor, taste, acid value (refer to GB / T 5530), and peroxide value (refer to GB / T 5538).

[0075] Table 1

[0076]

[0077]

[0078] Table 2

[0079]

[0080] Conclusion: From the above data, it can be seen that the fishy smell of flaxseed oil obtained after a series of treatments is significantly reduced and removed. The deodorization of flaxseed oil with green tea polyphenols and the addition of flavor stabilizers have a good application effect on the deodorization of flaxseed oil. The reduction of peroxide value also inhibits or slows down the harm caused by oxidation of flaxseed oil to the human body, while increasing the storage time of flaxseed oil.

[0081] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for removing volatile fishy smell components from linseed oil, characterized in that: The following steps are involved: Step 1: After pretreatment of flaxseed degumming, ultrasonic treatment is performed for 20-30 minutes and then supercritical extraction is performed for 2-3 hours to obtain crude flaxseed oil, a deacidifying agent is added, and the mixture is stirred in a water bath at 60-70° C. for 20-30 minutes, and centrifuged to obtain deacidified flaxseed oil; Step 2: add the composite adsorbent to the deacidified linseed oil obtained in step 1, stir at 60°C for 20-30 minutes, and centrifuge to obtain decolorized linseed oil; Step 3: Take the decolorized linseed oil prepared in step 2, add green tea polyphenols, shake at 60°C for 20-30 minutes, centrifuge at high speed after cooling, add flavor stabilizer, and stir evenly.

2. The method for removing volatile fishy smell components in linseed oil according to claim 1, characterized in that: The composite adsorbent in step 2 includes alkaline activated clay and activated carbon, wherein the activated carbon comes from the heat treatment carbonization of flax seed straw, and the specific steps include: immersing the flax seed straw in a zinc chloride solution with a concentration of 25g:1L for 2-3h, drying at 80°C and then heat treating, heating to 600°C under an argon gas flow, keeping the temperature for 1h, grinding evenly after cooling, fully pickling with sulfuric acid and then washing with deionized water to neutrality, and drying to obtain activated carbon.

3. A method for removing volatile fishy smell components in linseed oil according to claim 2, characterized in that: The preparation steps of the alkalized activated clay include: mixing the activated clay with alkali solution, adjusting the pH value to 7.4-8.9, filtering, drying, crushing and sieving to obtain the alkalized activated clay.

4. The method for removing volatile fishy smell components in linseed oil according to claim 1, characterized in that: The specific steps of the degumming pretreatment in step 1 include: separating the flaxseed from the shell and kernel, crushing and sieving the separated flaxseed kernel, dissolving it in deionized water, adding pectinase to hydrolyze it at 32-38° C. for 3 hours, and freeze-drying it after centrifugation.

5. The method for removing volatile fishy smell components in linseed oil according to claim 1, characterized in that: In step 1, the supercritical extraction is set at a CO2 flow rate of 20-30 kg / h, an extraction temperature of 40° C., and an extraction pressure of 3-5 MPa.

6. The method for removing volatile fishy smell components in linseed oil according to claim 1, characterized in that: The preparation steps of the deacidifying agent in step 1 include: stirring diatomaceous earth mixed with alkali solution at 60° C. for 1-2 hours, filtering and crushing, and drying for later use; wherein the solid-to-liquid ratio of diatomaceous earth to alkali solution is 1:(4-5).

7. The method for removing volatile fishy smell components in linseed oil according to claim 1, characterized in that: The flavor stabilizer in step 3 includes the following raw materials in parts by weight: 20-30 parts of plant essential oil, 40-50 parts of modified lignans, 0.5-1.0 parts of tert-butylhydroquinone, 0.2-0.3 parts of butylated hydroxyanisole and 5-8 parts of vitamin E.

8. The method for removing volatile fishy smell components in linseed oil according to claim 7, characterized in that: The plant essential oil is one or more combinations of grapefruit peel essential oil, clove basil essential oil and lemongrass essential oil.

9. The method for removing volatile fishy smell components in linseed oil according to claim 7, characterized in that: The preparation steps of the modified lignan include: separating the flaxseed from the flaxseed in step 1 from the hull to the kernel, ball-milling the separated flaxseed hull for 3-5 hours, adding an ethanol solution, stirring for 1 hour at 4°C in the dark, performing supercritical extraction, setting the pressure to 9MPa, extracting for 30 minutes at 35°C, taking out and centrifuging for 5 minutes at 5000r / min, collecting the supernatant, performing alkaline hydrolysis for 20 minutes, adjusting to neutrality, and performing high-speed centrifugation to obtain purified lignan, adding lauroyl chloride and methanesulfonic acid to the mixture, stirring in a water bath at 40°C for 2 hours, adding ice water after cooling, vacuum filtering, washing, and freeze-drying to obtain the modified lignan.

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