Preparation method of hydroxy fatty acid branched-chain fatty acid ester

Abstract

The invention discloses a preparation method of hydroxy fatty acid branched chain fatty acid ester, which comprises the following steps: preparing different types of hydroxy fatty acids by using unsaturated fatty acid as a raw material and adopting fatty hydratase; esterifying hydroxy fatty acid and glycerol to obtain hydroxy fatty glyceride; then synthesizing tri-hydroxy fatty acid branched-chain fatty acid ester triglyceride from hydroxy fatty acid glyceride and fatty acid acyl chloride through esterification reaction; purifying again by a molecular distillation technology, and carrying out directional hydrolysis by taking water as a substrate and lipase as a catalyst to generate hydroxy fatty acid branched chain fatty acid ester; and finally, through secondary molecular distillation deep purification, the high-purity hydroxy fatty acid branched chain fatty acid ester is successfully prepared. The technology has the advantages of simplicity and convenience in operation, high large-scale mass production capacity, wide application scene and the like, and a new idea is provided for synthesis of hydroxy fatty acid branched-chain fatty acid ester.

Description

Technical Field

[0001] This invention belongs to the field of oil processing technology, specifically relating to a method for preparing hydroxy fatty acid branched fatty acid esters. Background Technology

[0002] Branched-chain fatty acid esters (FAHFAs) are found in human blood and adipose tissue and have potential anti-inflammatory and insulin-resistance-improving functions. They are fatty acid esters composed of one molecule of fatty acid and one molecule of hydroxy fatty acid.

[0003] Among them, 9-palmitoyl hydroxystearate (9-PAHSA, where "9" represents the ester bond position, PA stands for palmitic acid, and HSA stands for hydroxystearic acid) and 5-palmitoyl hydroxystearate (5-PAHSA) have been studied most extensively. They can alleviate inflammation of adipose tissue in rodents and improve type 2 diabetes.

[0004] However, the synthesis of this type of lipid is still in the early experimental stages and cannot be mass-produced at present. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing hydroxy fatty acid branched fatty acid esters.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing hydroxy fatty acid branched fatty acid esters, comprising, Using unsaturated fatty acids and water as raw materials, fatty acid hydratase is used to convert unsaturated fatty acids into hydroxy fatty acids. Hydroxy fatty acids were introduced into glycerol using immobilized lipase to obtain hydroxy fatty acid glycerides; Hydroxy fatty acid glycerides are esterified by using fatty acid acyl chlorides under the action of an acid-binding agent to obtain hydroxy fatty acid branched fatty acid glycerides (TG-FAHFA). TG-FAHFA was purified by molecular distillation; TG-FAHFA was hydrolyzed using immobilized lipase to obtain hydroxy fatty acid branched-chain fatty acid esters, which were then purified by molecular distillation to obtain high-purity hydroxy fatty acid branched-chain fatty acid esters (FAHFA).

[0009] As a preferred embodiment of the preparation method described in this invention, the unsaturated fatty acid is one or more of Δ-9 palmitoleic acid, Δ-9 oleic acid, Δ-9,12-linoleic acid, Δ-9,12,15-linolenic acid, Δ-5,8,11,14-eicosapentaenoic acid, Δ-11 oleic acid, Δ-6,9,12-linolenic acid, Δ-15-nervonic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA).

[0010] In a preferred embodiment of the preparation method described in this invention, the synthesis conditions for the hydroxy fatty acid are as follows: The mass ratio of 50 mM phosphate buffer to unsaturated fatty acids is 1:20 to 1:40, the pH is maintained at 6, 0.1% bovine serum albumin is added, the mass of fatty acid hydratase is 2% to 6% of the mass of unsaturated fatty acids, the reaction temperature is 35℃, the reaction time is 6 to 12 h, and the reaction system needs to be purged with nitrogen.

[0011] In a preferred embodiment of the preparation method described in this invention, the synthesis conditions for the hydroxy fatty acid glyceride are as follows: Using glycerol and hydroxy fatty acids as substrates, n-hexane as solvent, water is removed by molecular sieve, the molar ratio of glycerol to hydroxy fatty acids is 1:5 to 1:8, the reaction time is 3 to 8 hours, the reaction temperature is 35 to 50 °C, and the enzyme accounts for 8% to 10% of the total mass of organisms. The amount of hexane added is 10 to 20 times the total mass of the substrate, and the amount of molecular sieve added is 10% to 20% of the total mass of the substrate.

[0012] In a preferred embodiment of the preparation method described in this invention, the fatty acid acyl chloride is one of the following: hexanoyl chloride, caprylic acid acyl chloride, capric acid acyl chloride, lauric acid acyl chloride, myristic acid acyl chloride, palmitic acid acyl chloride, palmitoleic acid acyl chloride, stearic acid acyl chloride, oleic acid acyl chloride, linoleic acid acyl chloride, linolenic acid acyl chloride, arachidic acid acyl chloride, arachidonic acid acyl chloride, behenic acid acyl chloride, lignochlorophenolic acid acyl chloride, EPA acyl chloride, DPA acyl chloride, DHA acyl chloride, and nervonic acid acyl chloride. The acid-binding agent is one or more of triethylamine, pyridine, and N,N-diisopropylethylamine.

[0013] As a preferred embodiment of the preparation method described in this invention, the conditions for the esterification synthesis of TG-FAHFA are as follows: The substrate molar ratio is 1:4 to 1:8, the temperature is 25 to 40℃, the time is 16 to 32 h, the amount of acid-binding agent added is 10 to 15% of the total mass of the substrate, a solvent is added to aid dissolution, and a quenching agent is used to quench the reaction after it is completed. The solvent is one of dichloromethane or trichloromethane, and the amount added is 5 to 8 times the total mass of the substrate; The quenching agent is one of water, ethanol or methanol, and the amount added is 1 to 1.5 times the total mass of the substrate.

[0014] In a preferred embodiment of the preparation method described in this invention, the parameters for the molecular distillation purification of TG-FAHFA are as follows: Feed rate 0.5-1.5 mL / min, absolute pressure 1-4 Pa, evaporation surface temperature 120-180℃, condensation surface temperature 20-40℃, scraper rotation speed 120 r / min, and the distillation residue is high-purity TG-FAHFA.

[0015] As a preferred embodiment of the preparation method described in this invention, the immobilized lipase is one or more of Palatase 20000L, Novozym 435, Lipozyme TL IM, Lipozyme RM IM, Novozym 40086, Lipase AY, Lipase DF-15, IM-NE100, NE-10, NE-20, R-001, RIM-03, AP6, and Amano PS.

[0016] In a preferred embodiment of the preparation method described in this invention, the conditions for TG-FAHFA enzymatic hydrolysis are as follows: Using water and TG-FAHFA as substrates, with a molar ratio of 1:600 ​​to 1:1200, the reaction time was 6 to 12 hours, the reaction temperature was 30 to 40°C, the enzyme accounted for 6% to 12% of the total substrate mass, and the emulsifier accounted for 0.2% of the total substrate mass. The emulsifier is one or more of the following: deoxycholate, Tween 20, Triton 100, PEG-400, and polyricinoleate; The parameters for molecular distillation separation of FAHFA are: Evaporation surface temperature 200-240℃, scraper rotation speed 160r / min, feed rate 1-1.6ml / min, condensation temperature 40℃, and distillate collected.

[0017] Beneficial effects of this invention: This invention develops a method for preparing branched-chain fatty acid esters of hydroxy fatty acids with a designable product structure. Compared with the method of directly using hydroxy fatty acids and fatty acids for esterification synthesis, the glycerol backbone in the hydroxy fatty acid glyceride is a protecting group of the hydroxy acid, which reduces the introduction of impurities during the synthesis process. If it is not protected, fatty acid impurities or straight-chain acid anhydride impurities will be introduced, resulting in low separation efficiency and low purity. Compared with the method of constructing FAFHA with terminal functional groups, this method has fewer operation steps and higher yield. Fatty acid hydratases can construct a variety of hydroxy fatty acids, and the ester bond positions of FAHFAs can be freely designed, providing a basis for exploring the relationship between the structure and function of branched fatty acid esters of different hydroxy fatty acids. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein: Figure 1 The liquid chromatogram is of 9-palmitoyl hydroxystearate triglyceride (TG-9-PAHSA) synthesized in Example 1.

[0019] Figure 2 This is a liquid chromatogram of the product obtained after enzymatic hydrolysis and molecular distillation purification of 9-PAHSA by TG-9-PAHSA in Example 1.

[0020] Figure 3 The image shows a secondary mass spectrum of 9-PAHSA in Example 1, where the instrument used was ultra-high performance liquid chromatography-quadrupole tandem time-of-flight mass spectrometry (UPLC-Q-TOF).

[0021] Figure 4 This is a secondary mass spectrum of 12-myristic acid hydroxystearate (12-MAHSA) in Example 2, where the instrument used was UPLC-Q-TOF.

[0022] Figure 5 This is a secondary mass spectrum of 12-lauric hydroxyoleic acid (12-LAHOA) in Example 3, where the instrument used was UPLC-Q-TOF. Detailed Implementation

[0023] 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 with reference to the examples in the specification.

[0024] Unless otherwise specified, all raw materials used in the embodiments of this invention are commercially available; the mass spectrometry detection of FAHFA in this invention is performed in negative ion mode.

[0025] Example 1 This embodiment provides a method for preparing hydroxy fatty acid branched fatty acid esters, including the following steps: (1) Weigh 20g of Δ9-oleic acid, add 400g of 50mM phosphate buffer solution, adjust pH=6, add 0.42g of BSA, add 0.4g of lipase (enzyme activity: 300 IUN / g), stir at 35℃ for 16h, after the reaction is completed, use 50ml of chloroform to extract 9-hydroxystearic acid in the system, extract 2 to 3 times, combine the chloroform phases, remove water with anhydrous sodium sulfate, filter to remove anhydrous sodium sulfate, and then evaporate the solvent in vacuum to obtain product I (which mainly contains 9-hydroxystearic acid); (2) Add product I and 2g glycerol to the reaction vessel, and add 280mL n-hexane, 5g 4A molecular sieve, and finally 2.5g Lipozyme RM IM (enzyme activity: 275 IUN / g). The mixture was stirred at 45°C for 8 hours. After the reaction was completed, the enzyme and molecular sieve were removed by filtration. The hexane phase was then washed with saturated brine. The hexane phase was then separated and an appropriate amount of anhydrous sodium sulfate was added. The anhydrous sodium sulfate was removed by filtration. Finally, n-hexane was rotary evaporated under vacuum to obtain product II (which contains hydroxy fatty acid triglycerides, diesters, a small amount of monoesters, and a small amount of unreacted product I). (3) Dissolve product II in 500 mL of dichloromethane, add 6 mL of pyridine dropwise while stirring, and add 30 g of palmitoyl chloride dropwise after stirring until homogeneous, and stir for 16 h. After the reaction was complete, 50 mL of anhydrous ethanol was added to quench palmitoyl chloride. Then, the dichloromethane phase was washed with 300 mL of 0.5 M hydrochloric acid aqueous solution, 300 mL of saturated sodium bicarbonate aqueous solution, and 300 mL of saturated saline solution. Finally, anhydrous sodium sulfate was used to remove water. The dichloromethane was then rotary evaporated under vacuum to obtain product III (which contains 9-palmitoylhydroxystearic acid triglyceride (TG-9-PAHSA), diester (DG-9-PAHSA), a small amount of monoester (MG-9-PAHSA), a small amount of product I, and ethyl palmitate). Its composition is shown in the figure. Figure 1 ; (4) Product III was purified by molecular distillation under the following conditions: feed rate 1.5 mL / min, evaporation surface temperature 180 °C, condensation surface temperature 40 °C, absolute pressure 3 Pa, and scraper rotation speed 120 r / min. The distillate was collected as product IV (which contained TG-9-PAHSA, DG-9-PAHSA and a small amount of MG-9-PAHSA). (5) Add product IV to 400g of water, add 0.9g of deoxycholate, and then add 34g of Lipozyme RMIM. React at 40℃ for 8h. After the reaction, filter to remove the enzyme, and extract the enzyme and aqueous phase separately with 100mL of n-hexane (extract 2-3 times). Combine the n-hexane, add anhydrous sodium sulfate to remove water, and rotary evaporate the n-hexane under vacuum to obtain product V (which contains 9-PAHSA and some unreacted TG-FAHFA). Its composition is shown in [reference needed]. Figure 2 A.

[0026] (6) Product V was purified by molecular distillation under the following conditions: evaporation surface temperature 220℃, feed rate 1.6 mL / min, scraper rotation speed 160 r / min, absolute pressure 3 Pa, and condensation temperature 40℃. The distillate phase was 9-PAHSA, and its liquid chromatogram is shown in [Figure number missing]. Figure 2 B, see secondary mass spectrum. Figure 3 The quasi-molecular ion [MH] with m / z 537.4477 belongs to 9-PAHSA. - The fragment at m / z 255.2075 is a palmitic acid-derived ion; this palmitic acid comes from 9-PAHSA; the characteristic ion at m / z 281.2216 comes from the dehydration product of hydroxystearic acid; the characteristic fragment at m / z 299.2363 comes from hydroxystearic acid in PAHSA.

[0027] Example 2 The difference between this embodiment and Embodiment 1 is that: Δ-9 oleic acid in (1) was replaced with Δ-11 oleic acid, and palmitoyl chloride in (3) was replaced with myristoyl chloride. The remaining steps were the same as in Example 1, and 12-MAHSA was obtained.

[0028] The secondary mass spectrum of 12-MAHSA in Example 2 is shown below. Figure 4 The quasi-molecular ion [MH] with m / z 509.4171 belongs to 12-MAHSA. - The fragment at m / z 227.1852 is a myristic acid-derived ion; this myristic acid comes from 12-MAHSA; the characteristic ion at m / z 281.2281 comes from the dehydration product of hydroxystearic acid; the characteristic fragment at m / z 299.2363 comes from hydroxystearic acid in MAHSA.

[0029] Example 3 The difference between this embodiment and Embodiment 1 is that: Δ-9 oleic acid in (1) was replaced with Δ-9,12-linoleic acid, and oleoyl chloride in (3) was replaced with lauroyl chloride. The remaining steps were the same as in Example 1, and 12-LAHOA was obtained.

[0030] The secondary mass spectrum of 12-LAHOA in Example 3 is shown below. Figure 5 The m / z value of 479.3683 is attributed to the quasi-molecular ion [MH] of 12-LAHOA. - The fragment at m / z 199.1555 is a lauric acid-derived ion; this lauric acid comes from 12-LAHOA; the characteristic ion at m / z 279.2124 comes from the dehydration product of hydroxyoleic acid; the characteristic fragment at m / z 297.2175 comes from hydroxyoleic acid in LAHOA.

[0031] The anti-inflammatory activity of the FAHFAs from Examples 1, 2, and 3 was studied using bone marrow-derived macrophages (BMDM) (exfoliated from mice) as a model, with lipopolysaccharide (LPS) stimulation for polarization. FAHFA was administered at 50 µM (24 h, with administration and stimulation occurring simultaneously). The levels of Tnf-α, IL-6, IL-1β, and IL-16 in the supernatant were detected using an ELISA kit, and the results are shown in Table 1. It can be seen that all three FAHFAs can reduce the secretion of inflammatory factors, with 9-PAHSA showing the best effect.

[0032] Table 1

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is as follows: The reaction time in step (2) was changed to 3 hours, and the remaining steps were the same as in Example 1, to obtain 9-PAHSA.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is as follows: The molecular distillation evaporation surface temperature in step (4) was changed to 110°C, and the remaining steps were the same as in Example 1, to obtain 9-PAHSA.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 is as follows: The reaction time in step (5) was changed to 16 hours, and the remaining steps were the same as in Example 1, to obtain 9-PAHSA.

[0036] Comparative Example 4 The difference between this comparative example and Comparative Example 2 is: The molecular distillation in step (6) was changed to two-stage molecular distillation. The conditions for the first-stage molecular distillation were: feed rate 1.6 mL / min, evaporation surface temperature 180°C, scraper rotation speed 150 r / min, condensation surface temperature 50°C, and absolute pressure 3 Pa. The conditions for the second-stage molecular distillation were the same as in (6) of Example 1, and the remaining steps were the same as in Comparative Example 2. 9-PAHSA was obtained.

[0037] The lipid compositions of each stage of synthesis, separation and purification in Examples 1, 2 and 3 were compared with those in Comparative Examples 1, 2, 3 and 4 (hydroxy fatty acid triglycerides and TG-FAHFA were detected by high performance liquid chromatography equipped with a differential detector, and the chromatographic column was a silica column; the content of FAHFA was detected by UPLC-Q-TOF, C18 reversed-phase column, external standard method), as shown in Table 2.

[0038] Table 2

[0039] The following conclusions can be drawn: the purity of hydroxy fatty acid triglycerides directly affects the purity of the final product. The low content of hydroxy fatty acid triglycerides in Comparative Example 1 led to the introduction of palmitic acid during the subsequent esterification synthesis of TG-FAHFA. The separation of TG-FAHFA also significantly affects the product purity. In Comparative Example 3, incomplete separation of TG-FAHFA resulted in the accumulation of ethyl palmitate, which in turn led to the production of a large amount of palmitic acid after subsequent enzymatic hydrolysis. The longer the enzymatic hydrolysis time of TG-FAHFA, the higher the proportion of FAHFA in the product. Furthermore, Sn-1,3 specific lipases do not hydrolyze the ester bonds of FAHFA. Two-stage molecular distillation can improve the product purity during FAHFA purification. In Comparative Example 4, although ethyl palmitate was introduced in the previous step, two-stage molecular distillation still ensured the high purity of the product because one-stage molecular distillation removed the introduced palmitic acid.

[0040] Comparative Example 5 The difference between this comparative example and Example 1 is as follows: Replace the acyl chloride esterification method in step (3) with the sulfuric acid catalytic method for esterification reaction, replace palmitoyl chloride with palmitic acid (sulfuric acid accounts for 10% of the total mass of the substrate), and add sulfuric acid in an amount of 10% of the total mass of the substrate.

[0041] The results showed that although sulfuric acid catalysis could catalyze the production of a portion of TG-FAHFA, approximately 20%, the reaction was slow, and sulfuric acid also catalyzed the dehydration of hydroxy fatty acids, leading to a significant loss of raw materials (which is also the reason for the low synthesis efficiency of TG-FAHFA). Although subsequent reactions could still proceed, the yield was very low. Furthermore, sulfuric acid also carbonized the substrate, introducing new impurities. This indicates that a mild esterification method is crucial for the synthesis of TG-FAHFA and subsequent preparation of FAHFA.

[0042] The advantages of this invention compared to direct esterification synthesis using hydroxy fatty acids and fatty acids are as follows: the glycerol backbone in hydroxy fatty acid glycerides serves as a protecting group for the hydroxy acid, reducing the introduction of impurities during synthesis. Without protection, fatty acid impurities or straight-chain anhydride impurities are introduced, leading to low separation efficiency and low purity. Compared to methods that construct FAFHA using terminal functional groups, this method involves fewer steps and yields higher output. Fatty acid hydratases can construct various hydroxy fatty acids, allowing for free design of the ester bond positions in FAHFA.

[0043] 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 present invention.

Claims

1. A method for preparing a hydroxy fatty acid branched-chain fatty acid ester, characterized in that: include, Using unsaturated fatty acids and water as raw materials, fatty acid hydratase is used to convert unsaturated fatty acids into hydroxy fatty acids. Hydroxy fatty acids were introduced into glycerol using immobilized lipase to obtain hydroxy fatty acid glycerides; Hydroxy fatty acid glycerides are esterified by using fatty acid acyl chlorides under the action of an acid-binding agent to obtain hydroxy fatty acid branched fatty acid glycerides (TG-FAHFA). TG-FAHFA was purified by molecular distillation; TG-FAHFA was hydrolyzed using immobilized lipase to obtain hydroxy fatty acid branched-chain fatty acid esters, which were then purified by molecular distillation to obtain high-purity hydroxy fatty acid branched-chain fatty acid esters (FAHFA).

2. The preparation method according to claim 1, characterized in that: The unsaturated fatty acid is one or more of Δ-9 palmitoleic acid, Δ-9 oleic acid, Δ-9,12-linoleic acid, Δ-9,12,15-linolenic acid, Δ-5,8,11,14-eicosapentaenoic acid, Δ-11 oleic acid, Δ-6,9,12-linolenic acid, Δ-15-nervonic acid, eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA).

3. The preparation method according to claim 2, characterized in that: The synthesis conditions for the hydroxy fatty acid are as follows: The mass ratio of 50 mM phosphate buffer to unsaturated fatty acids is 1:20 to 1:40, the pH is maintained at 6, 0.1% bovine serum albumin is added, the mass of fatty acid hydratase is 2% to 6% of the mass of unsaturated fatty acids, the reaction temperature is 35℃, the reaction time is 6 to 12 h, and the reaction system needs to be purged with nitrogen.

4. The preparation method according to claim 1, characterized in that: The synthesis conditions for the hydroxy fatty acid glycerides are as follows: Using glycerol and hydroxy fatty acids as substrates, n-hexane as solvent, water is removed by molecular sieve, the molar ratio of glycerol to hydroxy fatty acids is 1:5 to 1:8, the reaction time is 3 to 8 hours, the reaction temperature is 35 to 50 °C, and the enzyme accounts for 8% to 10% of the total mass of organisms. The amount of hexane added is 10 to 20 times the total mass of the substrate, and the amount of molecular sieve added is 10% to 20% of the total mass of the substrate.

5. The preparation method according to claim 1, characterized in that: The fatty acid acyl chloride is one of the following: hexanoyl chloride, caprylic acid acyl chloride, capric acid acyl chloride, lauryl chloride, myristic acid acyl chloride, palmitoyl chloride, palmitoleic acid acyl chloride, stearic acid acyl chloride, oleic acid acyl chloride, linoleic acid acyl chloride, linolenic acid acyl chloride, arachidic acid acyl chloride, arachidonic acid acyl chloride, behenic acid acyl chloride, lignochlorophenolic acid acyl chloride, EPA acyl chloride, DPA acyl chloride, DHA acyl chloride, and nervonic acid acyl chloride. The acid-binding agent is one or more of triethylamine, pyridine, and N,N-diisopropylethylamine.

6. The preparation method according to claim 1 or 5, characterized in that: The conditions for the esterification synthesis of TG-FAHFA are as follows: The substrate molar ratio is 1:4 to 1:8, the temperature is 25 to 40℃, the time is 16 to 32 h, the amount of acid-binding agent added is 10 to 15% of the total mass of the substrate, a solvent is added to aid dissolution, and a quenching agent is used to quench the reaction after it is completed. The solvent is one of dichloromethane or trichloromethane, and the amount added is 5 to 8 times the total mass of the substrate; The quenching agent is one of water, ethanol or methanol, and the amount added is 1 to 1.5 times the total mass of the substrate.

7. The preparation method according to claim 6, characterized in that: The parameters for the molecular distillation purification of TG-FAHFA are as follows: Feed rate 0.5-1.5 mL / min, absolute pressure 1-4 Pa, evaporation surface temperature 120-180℃, condensation surface temperature 20-40℃, scraper rotation speed 120 r / min, and the distillation residue is high-purity TG-FAHFA.

8. The preparation method according to claim 1, characterized in that: The immobilized lipase is one or more of Palatase 20000L, Novozym 435, Lipozyme TL IM, Lipozyme RM IM, Novozym 40086, Lipase AY, Lipase DF-15, IM-NE100, NE-10, NE-20, R-001, RIM-03, AP6, and Amano PS.

9. The preparation method according to claim 1 or 8, characterized in that: The conditions for TG-FAHFA enzymatic hydrolysis are: Using water and TG-FAHFA as substrates, with a molar ratio of 1:600 ​​to 1:1200, the reaction time was 6 to 12 hours, the reaction temperature was 30 to 40°C, the enzyme accounted for 6% to 12% of the total substrate mass, and the emulsifier accounted for 0.2% of the total substrate mass. The emulsifier is one or more of deoxycholate, Tween 20, Triton 100, PEG-400, and polyricinoleate.

10. The preparation method according to claim 1, characterized in that: The parameters for molecular distillation separation of FAHFA are: Evaporation surface temperature 200-240℃, scraper rotation speed 160r / min, feed rate 1-1.6ml / min, condensation temperature 40℃, and distillate collected.

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