Preparation method of a healthy edible oil rich in diglyceride and its product

Abstract

The present invention belongs to the technical field of oil modification and deep processing of healthy foods, and discloses a preparation method and product of a healthy edible oil rich in diglycerides, specifically relating to a method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes. The present invention immobilizes enzymes through organic-inorganic hybrid hydrophobic mesoporous microspheres, which are successfully applied to the preparation of diglycerides by enzymatic glycerolysis and esterification. Different raw materials can be selected according to requirements to prepare diglyceride structural esters rich in different types of fatty acids. The diglyceride content and fatty acid composition in the obtained oil products rich in diglycerides are controllable, and the products are diverse, meeting the requirements of different application scenarios. Moreover, the crude diglyceride product of the present invention can be simply separated and purified to prepare an oil product rich in diglycerides, and the immobilized enzyme can also be reused multiple times, which is significantly superior to free enzymes and has great potential for industrial application.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil modification and intensive processing of healthy foods, and discloses a preparation method and product of a healthy edible oil rich in diacylglycerol, and particularly relates to a method for preparing a healthy edible oil rich in diacylglycerol by enzymatic glycerolysis and esterification using immobilized enzymes. Background Art

[0002] Diacylglycerol (DAG) is a structural lipid in which one fatty acid in a class of triacylglycerols (TAG) is replaced by a hydroxyl group and exists in natural oils. Its content in natural oils is usually 2% to 10%, second only to triacylglycerol. Diacylglycerol and triacylglycerol are basically similar in terms of flavor, taste, color, etc. In recent years, extensive studies have been carried out on the structural characteristics, functional properties and metabolic mechanisms of diacylglycerol. According to the different binding sites of acyl groups and hydroxyl groups, diacylglycerol can be divided into two isomers: 1,3-DAG and 1,2-DAG. These two isomers can be converted into each other under natural conditions, but the structure of 1,3-DAG is relatively stable. Under the equilibrium state, the ratio of 1,3-DAG to 1,2-DAG is usually 2:1 or 3:2. As a natural component of dietary lipids, diacylglycerol has some special functions. Studies have shown that the intake of diacylglycerol can increase satiety and energy consumption, and contribute to weight management and weight loss. In addition, diacylglycerol also has antioxidant, anti-inflammatory and lipid-lowering effects. Therefore, diacylglycerol is considered a natural component with potential health benefits. Generally speaking, diacylglycerol is an important natural oil component, and its structural characteristics, functional properties and metabolic mechanisms have been widely studied. Further research may help to reveal the health benefits of diacylglycerol and provide a scientific basis for its application in the food industry and the pharmaceutical field.

[0003] Due to the sensitivity of free enzymes to the environment, such as high temperature, organic reagents, acid-base environment, etc., they are easily inactivated, which limits the application of enzymes under various conditions. Immobilized enzymes can improve the thermal stability and tolerance of enzymes, make the enzymes easy to separate from the products, and can be reused. Therefore, the use of immobilized enzyme catalysts can bring various advantages to the production of DAG oils, such as diversification and simplification of post-treatment. At present, some commercial enzymes are commonly used as immobilized lipases for catalysis, such as Novozyme435, Lipozyme RM IM and Lipozyme TL IM, etc. However, these enzymes are not only expensive, but also the free enzymes are prone to swelling when adsorbed in materials such as macroporous acrylic resin, which limits the reuse of the enzymes. Therefore, it is necessary to develop more economical and practical immobilized enzyme catalysts with high reusability to promote the industrial production of DAG. Summary of the Invention

[0004] In view of this, the technical problem to be solved by the present invention is to provide a preparation method and product of a healthy edible oil rich in diglyceride aiming at the deficiencies of the above-mentioned existing technologies. The enzymatic preparation method of the DAG-rich oil has the advantages of high catalytic efficiency, high nutritional value of the product, simple operation, environmental friendliness, simple product separation, and suitability for large-scale production.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] The first object of the present invention is to provide a preparation method of hybrid hydrophobic SiO2 mesoporous microspheres. In an acidic ethanol system, a mixture of tetraethyl orthosilicate and n-octyltrimethoxysilane is added and stirred to prepare a macromolecular prepolymer; subsequently, water, isopropanol, a surfactant, and a co-surfactant are added to the macromolecular prepolymer to construct an O / W microemulsion and obtain hybrid hydrophobic SiO2 mesoporous microspheres.

[0007] Specifically, the specific preparation process of the hybrid hydrophobic SiO2 mesoporous microspheres is as follows:

[0008] (1) Obtaining the prepolymer: Tetraethyl orthosilicate and n-octyltrimethoxysilane are added to ethanol, stirred and mixed evenly, then hydrochloric acid is added, and stirring and rotary evaporation under reduced pressure are continued to obtain the prepolymer;

[0009] (2) Preparation of hybrid silica microspheres: A surfactant and a co-surfactant are dissolved in water and isopropanol as the continuous phase. The prepolymer prepared in step (1) is weighed and added to the continuous phase under stirring to form an O / W emulsion. Ammonia water is added to catalyze the secondary hydrolysis and polycondensation reaction, and after stirring for 20 min, it is left standing for 24 h to obtain hybrid silica microspheres;

[0010] (3) Post-treatment of the hybrid silica microspheres: The hybrid silica microspheres prepared in step (2) are subjected to pore expansion. The reaction solution is added with water, left standing, and the supernatant is poured off, then filtered by suction, washed successively with deionized water and ethanol, and dried; distilled water is added to the dried hybrid silica microspheres, stirred and dispersed, and then ammonia water is added and stirred to react to obtain hybrid porous spherical silica, that is, the hybrid hydrophobic SiO2 mesoporous microspheres.

[0011] Furthermore, the molar ratio of tetraethyl orthosilicate to n-octyltrimethoxysilane is 1:1 - 9:1; the surfactant is one of Triton-100, Span 80, Span 20, and polyethylene glycol 200, and the addition amount of the surfactant is 2.0 - 8.0% of the mass of the prepolymer; the co-surfactant is one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and ionic liquid, and the addition amount of the co-surfactant is 0.1 - 1.0% of the mass of the prepolymer; the concentration of ammonia water is 25 - 28%, and the added volume of ammonia water accounts for 1 - 5% of the entire reaction system.

[0012] Furthermore, the drying temperature is 50 - 60 °C, and the drying time is 12 - 24 h; ammonia water is added at a mass - volume ratio of SiO2:NH3 of 10:1, and the stirring reaction temperature is 70 °C, and the reaction time is 12 h.

[0013] The hybrid hydrophobic SiO2 mesoporous microspheres prepared by the above method have a size of 2 - 20 μm, a mesopore diameter of 4 - 16 nm, and a contact angle of 110 - 130°.

[0014] The second object of the present invention is to provide a method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes.

[0015] In order to achieve the above object, the present invention adopts the following technical scheme:

[0016] A method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes, the method specifically includes the following steps:

[0017] (1) Preparation of immobilized lipase: The free enzyme is immobilized on the hybrid hydrophobic SiO2 mesoporous microsphere carrier prepared by the above - mentioned method through physical adsorption to obtain immobilized lipase;

[0018] (2) Enzymatic preparation of oil rich in DAG: The raw material oil and glycerol raw material are mixed, and then added to the immobilized lipase obtained in step (1), and enzymatic glycerolysis reaction is carried out in a constant - temperature water bath; after the reaction ends, solid - liquid separation is carried out, the obtained solid product is immobilized lipase, and the obtained solution is a crude product of oil rich in DAG, and then through molecular distillation, an oil rich in DAG is obtained.

[0019] Optionally, the immobilization amount of the immobilized lipase is 50 - 250 mg / g, and the immobilization rate is 50 - 85%.

[0020] Optionally, the specific process for preparing immobilized lipase by physical adsorption is as follows:

[0021] The free enzyme is added to phosphate buffer to prepare an enzyme solution; the enzyme solution is mixed with a hydrophobic carrier for immobilization to obtain immobilized lipase; wherein,

[0022] the pH value of the enzyme solution is 5.0 - 10.0, the concentration is 10 - 100 mg / mL; the ratio of the mass of the hydrophobic carrier to the volume of the enzyme solution is 1:100 - 3.5:100 (m / v, g / mL); the immobilization time is 0.5 - 2 h, the incubation temperature is 20 - 40 °C; the pH value of the phosphate buffer is 5.0 - 10.0;

[0023] The free enzyme is one or a combination of phospholipase A1, Candida antarctica lipase, Rhizomucor miehei lipase, Pseudomonas cepacia lipase, Aspergillus niger lipase, Candida rugosa lipase, and immobilized lipase IM-NE100.

[0024] Optionally, in the step (2), the molar ratio of the raw material oil to glycerol is 1:3 - 3:1; the addition amount of the immobilized lipase is 1 - 5% of the substrate mass; the addition amount of water is 1 - 5% of the substrate mass; the temperature of the constant temperature water bath is 40 - 80°C; the glycerolysis reaction time is 1 - 6 h;

[0025] Moreover, purification is carried out by molecular distillation; the feeding rate of the molecular distillation is 2 - 10 mL / min, the distillation pressure is 10 - 50 Pa, the heating temperature is 170 - 200°C, and the scraper rotation speed is 250 - 300 r / min;

[0026] The raw material oil is one or a combination of rapeseed oil, linseed oil, soybean oil, corn oil, peanut oil, sesame oil, rice bran oil, sunflower oil, camellia oil, Acer truncatum Bunge oil, Malania oleifera Chun ex S. Lee oil, algal oil and fish oil rich in DHA, EPA, and ARA.

[0027] Furthermore, the quality of the healthy edible oil product rich in diglyceride prepared by the above method is as follows:

[0028] The acid value is between 0.10 - 1.5 mg KOH / g, the peroxide value is 0.10 - 0.15 g / 100 g, the DAG content is 40% - 80%, and sn-1,3:sn-1,2 = 9:1 - 2:1; the functional fatty acids contained include oleic acid, linoleic acid, linolenic acid, DHA, ARA, EPA, and nervonic acid.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] 1. The present invention uses the emulsion template method to prepare hybrid hydrophobic SiO2 mesoporous microspheres as the carrier, and the whole process of carrier preparation and hydrophobic modification is completed in one step, without the need for additional hydrophobic modification. It also overcomes the cumbersome steps of the existing carrier preparation that require calcination to remove the template agent and subsequent grafting of hydrophobic groups. The preparation process is simple, the raw materials are economically easy to obtain, the time consumption is short, the yield is high, it is easy to scale up, and it is green, safe and pollution-free.

[0031] 2. The present invention immobilizes the free enzyme through the carrier hybrid hydrophobic SiO2 mesoporous microspheres, and its activity, stability and the number of repeated uses are all higher than those of the free enzyme; the mesoporous structure of the carrier can not only efficiently load the enzyme, but also facilitate the mass transfer and heat transfer of the reaction substrate in the system.

[0032] 3. The immobilized lipase prepared and disclosed in the present invention can be widely used in the reaction of enzymatic glycerolysis to prepare diglycerides. Different raw materials can be selected according to needs to prepare DAG structural esters rich in different types of fatty acids. For example, algal oil and glycerol can be used to prepare structural esters rich in DHA, and linseed oil and glycerol can be used to prepare structural esters rich in linolenic acid. The DAG content and fatty acid composition in the obtained DAG-rich oil products are controllable, and the products are diverse, meeting the needs of different application scenarios. Moreover, the crude product obtained by enzymatic glycerolysis in the present invention only needs simple separation and purification to prepare the finished oil rich in DAG.

[0033] 4. The whole process of the present invention adopts solvent-free enzymatic catalysis, with mild reaction conditions, short reaction time, and simple separation. It does not produce by-products, a large amount of wastewater and secondary waste compared with traditional chemical catalysis methods, effectively saving costs. Compared with non-aqueous enzymatic catalysis methods, it does not require organic solvents, has high raw material concentration and product yield, and the immobilized enzyme can also be regenerated and reused multiple times, showing great potential for industrial application.

[0034] 5. The immobilized lipase prepared and disclosed in the present invention has much better thermal stability than free lipase, and still maintains 78.3% of its initial activity after being reused 10 times. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0036] Figure 1 (a) and (b) are respectively the SEM and TEM images of the carrier material PMOS obtained in Example 1, Figure 1 (c) is the contact angle of the carrier material PMOS obtained in Example 1 with water, Figure 1 (d) is the nitrogen adsorption-desorption isotherm of the carrier material PMOS obtained in Example 1.

[0037] Figure 2 It is a comparison chart of the activities of the immobilized enzyme, free enzyme and commercial enzyme in catalyzing the preparation of DAG in Example 1;

[0038] Figure 3 (a) is a comparison chart of the thermal stabilities of the free enzyme and the immobilized enzyme incubated at different temperatures for the same time, and (b) is a comparison chart of the stabilities of the immobilized enzyme and the free enzyme incubated at the same temperature for different times.

[0039] Figure 4It is the gas chromatogram of the finished product of rapeseed oil diglyceride in Example 1; among them, FFA represents free fatty acid, MAG represents monoglyceride, DAG represents diglyceride, and TAG represents triglyceride.

[0040] Figure 5 It is the relative activity diagram of the immobilized enzyme for the catalytic synthesis of rapeseed oil diglyceride in Example 1, with the immobilized enzyme repeated 10 times.

[0041] Figure 6 It is the composition table of healthy oils rich in diglyceride prepared from different oil raw materials. Detailed implementation manners

[0042] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0043] The special term "embodiment" used here, any embodiment described as "exemplary" does not have to be construed as superior to or better than other embodiments. For the performance index tests in the embodiments of the present application, unless otherwise specified, the conventional test methods in the art are adopted. It should be understood that the terms described in the present application are only used to describe specific implementation manners and are not used to limit the content disclosed in the present application.

[0044] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as those commonly understood by those of ordinary skill in the technical field to which the present application belongs; the test methods and technical means not otherwise specifically noted in the present application refer to the experimental methods and technical means commonly adopted by those of ordinary skill in the art.

[0045] In order to better illustrate the content of the present application, numerous specific details are given in the following specific embodiments. Those skilled in the art should understand that the present application can still be implemented without some specific details. In the embodiments, some methods, means, instruments, equipment, etc. well-known to those skilled in the art are not described in detail in order to highlight the gist of the present application.

[0046] On the premise of no conflict, the technical features disclosed in the embodiments of the present application can be combined arbitrarily, and the obtained technical solutions belong to the content disclosed in the embodiments of the present application.

[0047] The present invention discloses a method for preparing a healthy edible oil rich in diglyceride by enzymatic glycerolysis and esterification using an immobilized enzyme.

[0048] To better understand the present invention, the following specific embodiments are used to further elaborate on the present invention, but it should not be construed as a limitation to the present invention. For those skilled in the art, some non-essential improvements and adjustments made based on the above-mentioned invention content are also considered to fall within the protection scope of the present invention.

[0049] It should be noted that the detection of the DAG product generated by the enzymatic glycerolysis catalyzed by the hybrid hydrophobic SiO2 mesoporous microsphere-immobilized enzyme is mainly carried out by gas chromatography. The gas chromatography detection conditions are as follows:

[0050] The chromatographic column is DB-5HT (15m×0.320mm, 0.10μm). The inlet temperature is 380°C, the injection volume is 1μL, and the split ratio is 50:1. High-purity helium is used as the carrier gas with a flow rate of 2mL / min. The hydrogen flow rate is 32mL / min, and the air flow rate is 200mL / min. The detector is an FID detector with a temperature of 380°C. The column oven temperature program: the initial temperature is 170°C and held for 2min, then heated to 380°C at a rate of 5°C / min and held for 6min.

[0051] The detection of fatty acids in the DAG product generated by the enzymatic glycerolysis catalyzed by the hybrid hydrophobic SiO2 mesoporous microsphere-immobilized enzyme is mainly carried out by gas chromatography. The gas chromatography detection conditions are as follows:

[0052] Equipped with a flame ionization detector (FID) and a capillary column (DB-FastFAME, 30m×0.250mm×0.25μm). The injection volume is 1μL, the carrier gas (nitrogen) flow rate is set to 2.0mL / min, and the split ratio is 1:10. The column oven temperature program is to hold at 165°C for 3.6min, then rise to 230°C at a rate of 20°C / min and hold for 6min. The temperatures of the detector and the inlet are 260°C and 280°C respectively. The fatty acid composition is judged according to the retention time of the fatty acid methyl ester standard. The content of each fatty acid is calculated by the peak area normalization method.

[0053] Example 1

[0054] An enzymatic preparation method of rapeseed oil rich in DAG specifically includes the following steps:

[0055] (1) Preparation of Hybrid Hydrophobic SiO2 Mesoporous Microspheres: Inorganic-organic hybrid mesoporous silica spheres were prepared by the sol-gel method. First, an inorganic-organic hybrid copolymer was prepared. Take a 250 mL three-necked flask and add 58.5 g of tetraethyl orthosilicate and 7.4 g of n-octyltrimethoxysilane (molar ratio 9:1), 17.7 mL of absolute ethanol. Under a 30 °C water bath, mechanically stir and mix evenly at a speed of 700 r / min. While continuously stirring, slowly add 6 mL of 0.1 M hydrochloric acid solution. After continuously stirring for 60 min, stop stirring. Transfer the reactants into a 500 mL rotary evaporation flask and rotary evaporate at 80 °C, 120 r / min, and -0.01 KPa for 20 min to remove ethanol and hydrochloric acid in the solution to obtain an inorganic-organic hybrid prepolymer. Take a 1000 mL three-necked flask and add 150 mL of pure water, 50 mL of isopropanol, 2 g of Triton X-100 (4% of the mass of the prepolymer), and 0.3 g of sodium dodecyl sulfate (0.6% of the mass of the prepolymer). In a 30 °C water bath, mechanically stir and mix evenly at 700 r / min. While continuously stirring, weigh 50 g of the above hybrid prepolymer and add it to the mixture to form an O / W emulsion. Continue to stir for 5 min, then add ammonia water with a percentage concentration of 2% of the entire reaction system. After mechanically stirring for 20 min, add 100 ml of pure water and ultrasonically disperse for 2 min. Let it stand for 5 h, then pour out the supernatant. Take the precipitate and filter and wash it 2-3 times with deionized water and absolute ethanol respectively to remove the surfactant. Put the washed precipitate into an oven at 50 °C and dry it for 24 h, then take it out to obtain the prepared inorganic-organic hybrid mesoporous silica spheres PMOS and store them in a drying dish for the next step. The morphology is as Figure 1 shown in a, b, with a size between 2 - 10 μm, and the contact angle is as Figure 1 shown in c, and the pore size distribution is as Figure 1 shown in d, which is 4 - 16 nm.

[0056] (2) Enzyme Immobilization: Dissolve 15 g of free enzyme Aspergillus niger lipase in 100 mL of phosphate buffer solution (50 mM) with a pH of 6. Mix the carrier and the enzyme solution at a solid-liquid ratio of 10 mg / mL, ultrasonically disperse for 5 min, evacuate for 5 min, incubate in a shaker at 30 °C for 30 min and then centrifuge; then, freeze-dry the precipitate to obtain immobilized lipase (the immobilization amount is 75 mg / g, and the immobilization rate is 50%).

[0057] (3) Catalytic Glycerolysis Reaction: Take 100 g of rapeseed oil and 3.5 g of glycerol and place them in a 250 mL reaction flask (molar ratio 3:1). Add 3 g of the above immobilized lipase (3% of the mass of rapeseed oil). Mechanically stir the reaction for 4 h, then centrifuge and take the supernatant, which is a crude product rich in DAG (the content of diglyceride is 46.8%); subject the crude product to molecular distillation, with a feed rate of 2 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraper rotation speed of 250 r / min to obtain a refined oil rich in DAG.

[0058] The acid value of this product was measured to be 0.17 mg KOH / g, the peroxide value was 0.121 g / 100 g, the diglyceride content was 62.1%, and sn-1,3:sn-1,2 = 9:1.

[0059] Example 2

[0060] An enzymatic preparation method of DAG-rich linseed oil, specifically including the following steps:

[0061] (1) Preparation of hybrid hydrophobic SiO2 mesoporous microspheres: Prepare inorganic-organic hybrid mesoporous silica spheres by the sol-gel method. First, prepare an inorganic-organic hybrid copolymer. Take a 250 mL three-necked flask and add 52 g of tetraethyl orthosilicate and 7.4 g of n-octyltrimethoxysilane (molar ratio 8:1), 17.7 mL of absolute ethanol, and a 30 °C water bath. Mechanically stir and mix evenly at a rotation speed of 700 r / min. While continuously stirring, gradually add 6 mL of 0.1 M hydrochloric acid solution. Stop stirring after continuously stirring for 60 min. Transfer the reactants to a 500 mL rotary evaporation flask and perform rotary evaporation at 80 °C, 120 r / min, and -0.01 KPa for 20 min to remove ethanol and hydrochloric acid in the solution to obtain an inorganic-organic hybrid prepolymer. Take a 1000 mL three-necked flask and add 150 mL of pure water, 50 mL of isopropanol, 2 g of Triton-100 (4% of the prepolymer mass), and 0.3 g of sodium dodecyl sulfate (0.6% of the prepolymer mass). Place it in a 30 °C water bath and mechanically stir and mix evenly. While continuously stirring, weigh 50 g of the above hybrid prepolymer and add it to the mixture to form an O / W emulsion. Continue to stir for 5 min, then add 2% ammonia water by mass concentration of the entire reaction system. After mechanically stirring for 20 min, add 100 ml of pure water and ultrasonically disperse for 2 min. Let it stand for 5 h, then pour out the supernatant. Take the precipitate and filter and wash it 2-3 times with deionized water and absolute ethanol respectively to remove surfactants. Put the washed precipitate into an oven at 55 °C and dry for 18 h, then take it out to obtain the prepared inorganic-organic hybrid mesoporous silica spheres PMOS and store them in a desiccator for the next step.

[0062] The size of the inorganic-organic hybrid mesoporous silica spheres PMOS is 4-16 μm, the contact angle is 120°, and the mesoporous pore diameter is 2-10 nm.

[0063] (2) Enzyme immobilization: Dissolve 10 g of free enzyme Aspergillus niger lipase (ANL) in 100 mL of phosphate buffer solution with a pH of 6. Mix the carrier and the enzyme solution at a solid-liquid ratio of 10 mg / mL, ultrasonically disperse for 5 min, evacuate for 5 min, incubate in a shaker at 35 °C for 40 min, and then centrifuge; then, freeze-dry the precipitate to obtain immobilized lipase (the immobilization amount is 95 mg / g, and the immobilization rate is 55%).

[0064] (3) Catalyze the glycerolysis reaction: Put 100 g of linseed oil and 5.2 g of glycerol into a 250 mL reaction flask (molar ratio 2:1), add 3 g of the above-mentioned immobilized lipase (3% of the mass of linseed oil), mechanically stir the reaction for 3 h, then centrifuge and take the supernatant, which is a crude product rich in DAG (the content of diglyceride is 46.8%); subject the crude product to molecular distillation, with a feeding rate of 2 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraper rotation speed of 250 r / min to obtain a refined oil rich in DAG.

[0065] After determination, the acid value of this product is 0.5 mg KOH / g, the peroxide value is 0.120 g / 100 g, the diglyceride content is 57.9%, and sn-1,3:sn-1,2 = 7:1.

[0066] Example 3

[0067] An enzymatic preparation method of a tea seed oil rich in DAG, specifically including the following steps:

[0068] (1) Preparation of hybrid hydrophobic SiO2 mesoporous microspheres: Prepare inorganic-organic hybrid mesoporous silica spheres by the sol-gel method. First, prepare an inorganic-organic hybrid copolymer. Take a 250 mL three-necked flask and add 45.5 g of tetraethyl orthosilicate and 7.4 g of n-octyltrimethoxysilane (molar ratio 7:1), 17.7 mL of absolute ethanol, water bath at 30 °C, mechanically stir and mix evenly at a rotation speed of 700 r / min, and gradually add 6 mL of 0.1 M hydrochloric acid solution dropwise under continuous stirring. Stop stirring after continuous stirring for 60 min. Transfer the reactants to a 500 mL rotary evaporation flask, and rotary evaporate at 80 °C, 120 r / min, and -0.01 KPa for 20 min to remove ethanol and hydrochloric acid in the solution to obtain an inorganic-organic hybrid prepolymer. Take a 1000 mL three-necked flask and add 150 mL of pure water, 50 mL of isopropanol, 2 g of Triton-100 (4% of the mass of the prepolymer), and 0.3 g of sodium dodecyl sulfate (0.6% of the mass of the prepolymer), water bath at 30 °C, mechanically stir and mix evenly. Under continuous stirring, weigh 50 g of the above-mentioned hybrid prepolymer and add it to the mixture to form an O / W emulsion. Continue stirring for 5 min, then add ammonia water with a percentage concentration of 2% of the whole reaction system, mechanically stir for 20 min, add 100 ml of pure water and ultrasonically disperse for 2 min, let it stand for 5 h, then pour out the supernatant, take the precipitate, and filter and wash it 2-3 times with deionized water and absolute ethanol respectively to remove the surfactant. Put the washed precipitate into an oven at 60 °C and dry it for 12 h, then take it out to obtain the prepared inorganic-organic hybrid mesoporous silica spheres PMOS and store them in a drying dish for the next step.

[0069] The size of the inorganic-organic hybrid mesoporous silica sphere PMOS is 4-14 μm, the contact angle is 118°, and the mesoporous pore diameter is 3-12 nm.

[0070] (2) Enzyme immobilization: Dissolve 10 g of free enzyme Aspergillus niger lipase in 100 mL of phosphate buffer solution with a pH of 6. Mix the carrier and the enzyme solution at a solid-liquid ratio of 10 mg / mL, ultrasonically disperse for 5 min, evacuate for 5 min, incubate in a shaker at 37 °C for 40 min and then centrifuge; then, freeze-dry the precipitate to obtain immobilized lipase (the immobilization amount is 150 mg / g and the immobilization rate is 75%).

[0071] (3) Catalyze the glycerolysis reaction: Take 100 g of camellia oil and 10.4 g of glycerol and place them in a 250 mL reaction flask (molar ratio 1:1). Add 3 g of the above immobilized lipase (accounting for 3% of the mass of camellia oil), mechanically stir the reaction for 1 h, then centrifuge and take the supernatant, which is a crude product rich in DAG (the content of diglyceride is 49.0%); subject the crude product to molecular distillation, with a feed rate of 2 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraper rotation speed of 250 r / min to obtain refined oil rich in DAG.

[0072] After measurement, the acid value of this product is 0.17 mg KOH / g, the peroxide value is 0.121 g / 100 g, the content of diglyceride is 59.7%, and sn-1,3:sn-1,2 = 5:1.

[0073] Example 4

[0074] An enzymatic preparation method of corn oil rich in DAG specifically includes the following steps:

[0075] (1) Preparation of hybrid hydrophobic SiO2 mesoporous microspheres: Inorganic-organic hybrid mesoporous silica spheres were prepared by the sol-gel method. First, an inorganic-organic hybrid copolymer was prepared. Take a 250 mL three-necked flask and add 58.5 g of tetraethyl orthosilicate and 7.4 g of n-octyltrimethoxysilane (molar ratio 9:1), 17.7 mL of absolute ethanol, and water bath at 30 °C. Stir mechanically at a speed of 700 r / min until evenly mixed. While stirring continuously, slowly add 6 mL of 0.1 M hydrochloric acid solution. Stop stirring after continuous stirring for 60 min. Transfer the reactants to a 250 mL rotary evaporation flask and perform rotary evaporation at 80 °C, 120 r / min, and -0.01 KPa for 20 min to remove ethanol and hydrochloric acid in the solution to obtain an inorganic-organic hybrid prepolymer. Take a 1000 mL three-necked flask and add 150 mL of pure water, 50 mL of isopropanol, 2 g of Triton X-100 (4% of the prepolymer mass), and 0.3 g of sodium dodecyl sulfate (0.6% of the prepolymer mass). Place it in a water bath at 30 °C and stir mechanically at 700 r / min until evenly mixed. While stirring continuously, weigh 50 g of the above hybrid prepolymer and add it to the mixture to form an O / W emulsion. Continue stirring for 5 min, then add 2% ammonia water by mass concentration of the whole reaction system. Stir mechanically for 20 min, then add 100 ml of pure water and ultrasonically disperse for 2 min. Let it stand for 5 h, then pour out the supernatant. Take the precipitate and filter and wash it 2-3 times with deionized water and absolute ethanol respectively to remove surfactants. Put the washed precipitate into an oven at 60 °C and dry for 12 h, then take it out to obtain the prepared inorganic-organic hybrid mesoporous silica spheres PMOS and store them in a drying dish for the next step.

[0076] The size of the inorganic-organic hybrid mesoporous silica spheres PMOS is 4-14 μm, the contact angle is 118°, and the mesoporous pore diameter is 3-12 nm.

[0077] (2) Enzyme immobilization: Dissolve 10 g of free enzyme Aspergillus niger lipase in 100 mL of phosphate buffer solution with a pH of 7. Mix the carrier and the enzyme solution at a solid-liquid ratio of 10 mg / mL, ultrasonically disperse for 5 min, evacuate for 5 min, incubate in a shaker at 37 °C for 40 min and then centrifuge; then, freeze-dry the precipitate to obtain immobilized lipase (the immobilization amount is 150 mg / g and the immobilization rate is 75%).

[0078] (3) Catalytic glycerolysis reaction: Take 100 g of corn oil and 20.8 g of glycerol and place them in a 250 mL reaction flask (molar ratio 1:2). Add 6 g of the above immobilized lipase (6% of the corn oil mass). Stir mechanically for 4 h and then centrifuge to take the supernatant, which is a crude product rich in DAG (the content of diglyceride is 50.5); perform molecular distillation on the crude product, with a feeding rate of 2 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraper speed of 250 r / min to obtain a refined oil rich in DAG.

[0079] The acid value of this product is measured to be 0.17 mg KOH / g, the peroxide value is 0.121 g / 100 g, the content of diglyceride is 60.5%, and sn-1,3:sn-1,2 = 2:1.

[0080] Example 5

[0081] An enzymatic preparation method of sunflower oil rich in DAG specifically includes the following steps:

[0082] (1) Preparation of hybrid hydrophobic SiO2 mesoporous microspheres: Prepare inorganic-organic hybrid mesoporous silica spheres by the sol-gel method. First, prepare an inorganic-organic hybrid copolymer. Take a 250 mL three-necked flask and add 58.5 g of tetraethyl orthosilicate and 7.4 g of n-octyltrimethoxysilane with a molar ratio of 9:1, 17.7 mL of absolute ethanol, and perform a water bath at 30°C. Mechanically stir and mix evenly at a rotation speed of 700 r / min. While continuously stirring, gradually add 6 mL of 0.1 M hydrochloric acid solution. Stop stirring after continuously stirring for 60 min. Transfer the reactants into a 500 mL rotary evaporation flask and perform rotary evaporation at 80°C, 120 r / min, and -0.01 KPa for 20 min to remove ethanol and hydrochloric acid in the solution to obtain an inorganic-organic hybrid prepolymer. Take a 1000 mL three-necked flask and add 150 mL of pure water, 50 mL of isopropanol, 4 g of Triton-100 (8% of the prepolymer mass), and 0.3 g of sodium dodecyl sulfate (0.6% of the prepolymer mass). Perform a water bath at 30°C and mechanically stir and mix evenly. While continuously stirring, weigh 50 g of the above hybrid prepolymer and add it to the mixture to form an O / W emulsion. Continue stirring for 5 min, then add ammonia water with a concentration of 2% of the entire reaction system, mechanically stir for 20 min, add 100 ml of pure water and ultrasonically disperse for 2 min, let it stand for 5 h, then pour out the supernatant. Take the precipitate and filter and wash it 2-3 times with deionized water and absolute ethanol respectively to remove surfactants. Put the washed precipitate into an oven at 60°C and dry it for 12 h, then take it out to obtain the prepared inorganic-organic hybrid mesoporous silica spheres PMOS and store them in a drying dish for the next step.

[0083] The size of the inorganic-organic hybrid mesoporous silica spheres PMOS is 4-14 μm, the contact angle is 115°, and the mesoporous pore diameter is 3-12 nm.

[0084] (2) Enzyme immobilization: Dissolve 10 g of free enzyme Aspergillus niger lipase in 100 mL of phosphate buffer solution with a pH of 6. Mix the carrier and the enzyme solution at a solid-liquid ratio of 10 mg / mL, ultrasonically disperse for 5 min, evacuate for 5 min, incubate in a shaker at 37°C for 40 min and then centrifuge; then, freeze-dry the precipitate to obtain immobilized lipase (the immobilization amount is 200 mg / g, and the immobilization rate is 80%).

[0085] (3) Catalyze the glycerolysis reaction: Take 100 g of sunflower oil and 31.2 g of glycerol and place them in a 250 mL reaction flask (molar ratio 1:3). Add 6 g of the above immobilized lipase (6% of the mass of sunflower oil) and pure water (1% of the mass of sunflower oil). After mechanical stirring for 4 h, centrifuge and take the supernatant, which is a crude product rich in DAG (the content of diglyceride is 52.3%); subject the crude product to molecular distillation, with a feeding rate of 2 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraping speed of 250 r / min to obtain a refined oil rich in DAG.

[0086] It was determined that the acid value of this product was 0.17 mg KOH / g, the peroxide value was 0.121 g / 100 g, the diglyceride content was 62.3%, and sn-1,3:sn-1,2 = 9:1.

[0087] Example 6

[0088] An enzymatic preparation method of rapeseed oil rich in DAG specifically includes the following steps:

[0089] (1) Preparation of hybrid hydrophobic SiO2 mesoporous microspheres: Prepare inorganic-organic hybrid mesoporous silica spheres by the sol-gel method. First, prepare an inorganic-organic hybrid copolymer. Take a 250 mL three-necked flask and add 58.5 g of tetraethyl orthosilicate and 7.4 g of n-octyltrimethoxysilane with a molar ratio of 9:1, 17.7 mL of absolute ethanol, and perform a water bath at 30 °C. Mechanically stir and mix evenly at a rotation speed of 700 r / min. While continuously stirring, gradually add 6 mL of 0.1 M hydrochloric acid solution. Stop stirring after continuously stirring for 60 min. Transfer the reactants to a 500 mL rotary evaporation flask and perform rotary evaporation at 70 °C, 120 r / min, and -0.01 KPa for 20 min to remove ethanol and hydrochloric acid in the solution to obtain an inorganic-organic hybrid prepolymer. Take a 1000 mL three-necked flask and add 150 mL of pure water, 50 mL of isopropanol, 4 g of Triton-100 (8% of the mass of the prepolymer), and 0.5 g of sodium dodecyl sulfate (0.6% of the mass of the prepolymer). Perform a water bath at 30 °C and mechanically stir and mix evenly at 700 r / min. While continuously stirring, weigh 50 g of the above hybrid prepolymer and add it to the mixture to form an O / W type emulsion. Continue stirring for 5 min and then add ammonia water with a percentage concentration of 2% of the entire reaction system. Mechanically stir for 20 min and then add 100 ml of pure water and ultrasonically disperse for 2 min. Let it stand for 5 h and then pour out the supernatant. Take the precipitate and filter and wash it 2-3 times with deionized water and absolute ethanol respectively to remove the surfactant. Put the washed precipitate into an oven at 50 °C and dry for 24 h, then take it out to obtain the prepared inorganic-organic hybrid mesoporous silica spheres PMOS and store them in a drying dish for the next step of use.

[0090] The inorganic-organic hybrid mesoporous silica spheres PMOS have a size of 4-14 μm, a contact angle of 123°, and a mesopore diameter of 4-12 nm.

[0091] (2) Enzyme immobilization: Dissolve 50 mL of free enzyme phospholipase A1 in 50 mL of phosphate buffer solution (50 mM) with a pH of 7. Mix the carrier and the enzyme solution at a solid-liquid ratio of 10 mg / mL, ultrasonically disperse for 5 min, evacuate for 5 min, incubate in a shaker at 37 °C for 120 min and then centrifuge; Then, freeze-dry the precipitate to obtain immobilized lipase (the immobilization amount is 120 mg / g and the immobilization rate is 60%).

[0092] (3) Catalyze the glycerolysis reaction: Take 200 g of rapeseed oil and 20.8 g of glycerol and place them in a 250 mL reaction flask (molar ratio is 1:2). Add 4 g of the above immobilized lipase (2% of the mass of rapeseed oil) and 2 g of pure water (1% of the mass of rapeseed oil). After mechanical stirring for 6 h, centrifuge and take the supernatant, which is a crude product rich in DAG (the content of diglyceride is 45.6%); Subject the crude product to molecular distillation, with a feeding rate of 2 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraping speed of 250 r / min to obtain refined oil rich in DAG.

[0093] It is measured that the acid value of this product is 0.17 mg KOH / g, the peroxide value is 0.121 g / 100 g, the diglyceride content is 56.6%, and sn-1,3:sn-1,2 = 8:1.

[0094] Example 7

[0095] A method for enzymatically preparing sesame oil rich in DAG specifically includes the following steps:

[0096] (1) Preparation of hybrid hydrophobic SiO2 mesoporous microspheres: The steps are the same as those in step (1) of Example 1.

[0097] (2) Enzyme immobilization: Dissolve 5 g of Pseudomonas cepacia lipase in 100 mL of phosphate buffer solution (50 mM) with a pH of 7. Mix the carrier and the enzyme solution at a solid-liquid ratio of 10 mg / mL, ultrasonically disperse for 5 min, evacuate for 5 min, incubate in a shaker at 37 °C for 120 min and then centrifuge; Then, freeze-dry the precipitate to obtain immobilized lipase (the immobilization amount is 120 mg / g and the immobilization rate is 60%).

[0098] (3) Catalyze the glycerolysis reaction: Take 200 g of sesame oil and 20.8 g of glycerol and place them in a 250 mL reaction flask (molar ratio is 1:2). Add 6 g of the above immobilized lipase (accounting for 3% of the mass of sesame oil). After mechanical stirring for 6 h, centrifuge and take the supernatant, which is a crude product rich in DAG (the content of diglyceride is 48.8%); subject the crude product to molecular distillation, with a feeding rate of 5 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraper rotation speed of 250 r / min to obtain a refined oil rich in DAG.

[0099] After determination, the acid value of this product is 0.17 mg KOH / g, the peroxide value is 0.121 g / 100 g, the content of diglyceride is 58.8%, and sn-1,3:sn-1,2 = 7:1.

[0100] Example 8

[0101] An enzymatic preparation method of an oil rich in DAG of rice bran oil, specifically including the following steps:

[0102] (1) Preparation of hybrid hydrophobic SiO2 mesoporous microspheres: The steps are the same as those in step (1) of Example 1.

[0103] (2) Enzyme immobilization: The steps are the same as those in step (2) of Example 7.

[0104] (3) Catalyze the glycerolysis reaction: Take 200 g of rice bran oil and 20.8 g of glycerol and place them in a 250 mL reaction flask (substrate molar ratio is 1:1). Add 6 g of the above immobilized lipase (accounting for 3% of the mass of rice bran oil). After mechanical stirring for 6 h, centrifuge and take the supernatant, which is a crude product rich in DAG (the content of diglyceride is 48.6%); subject the crude product to molecular distillation, with a feeding rate of 2 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraper rotation speed of 250 r / min to obtain a refined oil rich in DAG.

[0105] After determination, the acid value of this product is 0.17 mg KOH / g, the peroxide value is 0.121 g / 100 g, the content of diglyceride is 58.4%, and sn-1,3:sn-1,2 = 8:1.

[0106] Example 9

[0107] An enzymatic preparation method of an oil rich in DAG of rice bran oil, specifically including the following steps:

[0108] (1) Preparation of hybrid hydrophobic SiO2 mesoporous microspheres: The steps are the same as those in step (1) of Example 2.

[0109] (2) Enzyme immobilization: The steps are the same as those in step (2) of Example 4.

[0110] (3) Catalyze the glycerolysis reaction: Place 500 g of rice bran oil and 52 g of glycerol in a 1000 mL reaction flask (molar ratio 1:1), add 15 g of the above immobilized lipase (3% of the substrate mass), mechanically stir for 6 h, then centrifuge to obtain the supernatant, which is a crude product rich in DAG (the content of diglyceride is 52.3%); subject the crude product to molecular distillation, with a feeding rate of 2 mL / min, a distillation pressure of 10 Pa, a heating temperature of 180 °C, and a scraper rotation speed of 250 r / min to obtain a refined oil rich in DAG.

[0111] Upon measurement, the acid value of this product is 0.50 mg KOH / g, the peroxide value is 0.124 g / 100 g, the diglyceride content is 65.8%, and sn-1,3:sn-1,2 = 9:1.

[0112] Example 10

[0113] It is basically the same as Example 9, except that: in step (3), take 500 g of camellia seed oil, 26 g of glycerol, and 15 g of immobilized lipase, react at 55 °C for 6 h, and the crude product is molecular distilled to obtain the finished product.

[0114] Upon measurement, the acid value of this product is 0.50 mg KOH / g, the peroxide value is 0.124 g / 100 g, the diglyceride content is 59.4%, and sn-1,3:sn-1,2 = 8:1.

[0115] To further prove the beneficial effects of the present invention for better understanding of the present invention, the following comparative examples are used to further clarify the technical features disclosed in the present invention, but it should not be construed as a limitation to the present invention. For other improvements made by those skilled in the art based on the above invention content without creative work, they are also considered to fall within the protection scope of the present invention.

[0116] Comparative Example 1 A method for preparing rapeseed oil rich in DAG by enzymatic esterification, which specifically includes the following steps:

[0117] Catalyze the glycerolysis reaction: Place 28.2 g of rapeseed oil fatty acid and 18.4 g of glycerol in a 100 mL three-necked flask, add 1.692 g of the immobilized lipase in Example 1 above, mechanically stir at 65 °C for 6 h, then centrifuge to obtain the supernatant, which is a crude product rich in DAG; subject the crude product to molecular distillation, with a feeding rate of 3 mL / min, a distillation pressure of 20 Pa, a heating temperature of 180 °C, a scraper rotation speed of 240 r / min, and a condensation temperature of 30 °C to obtain a refined oil rich in DAG.

[0118] It was determined that the content of the crude product rich in DAG was 62.5%. After molecular distillation, the acid value of the product was 0.50 mg KOH / g, the peroxide value was 0.124 g / 100 g, the content of diglyceride was 81.8%, and sn-1,3:sn-1,2 = 8:1.

[0119] Comparative Example 2 A method for preparing DAG-rich soybean oil by enzymatic esterification is specifically operated as follows:

[0120] Catalyze the glycerolysis reaction: Take 29.2 g of soybean oil fatty acid and 18.4 g of glycerol and place them in a 100 mL three-necked flask. Add 2.856 g of the immobilized enzyme in Example 2 (6% of the total mass of the substrate). After mechanical stirring at 65 °C for 6 h, centrifuge and take the supernatant, which is the crude product rich in DAG; perform molecular distillation on the crude product, with a feeding rate of 3 mL / min, a distillation pressure of 20 Pa, a heating temperature of 180 °C, a scraper rotation speed of 240 r / min, and a condensation temperature of 30 °C to obtain the refined DAG-rich oil.

[0121] It was determined that the content of the crude product rich in DAG was 60.9%. After molecular distillation, the acid value of the product was 0.60 mg KOH / g, the peroxide value was 0.114 g / 100 g, the content of diglyceride was 80.3%, and sn-1,3:sn-1,2 = 9:1.

[0122] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes, characterized in that, The method specifically includes the following steps: (1) Preparation of immobilized lipase: Free enzyme is immobilized on a hybrid hydrophobic SiO2 mesoporous microsphere carrier by physical adsorption to obtain immobilized lipase; (2) Enzymatic preparation of DAG-rich oil: Raw material oil and glycerol raw material are mixed, and then added to the immobilized lipase obtained in step (1), and an enzymatic glycerolysis reaction is carried out in a constant temperature water bath; After the reaction is completed, solid-liquid separation is carried out. The obtained solid product is immobilized lipase, and the obtained solution is a crude product of DAG-rich oil, and then through molecular distillation, DAG-rich oil is obtained; In an acidic ethanol system, a mixture of tetraethyl orthosilicate and n-octyltrimethoxysilane is added, and stirred to prepare a macromolecular prepolymer; Subsequently, water, isopropanol, a surfactant and a co-surfactant are added to the macromolecular prepolymer to construct an O / W microemulsion and ammonia water is added to catalyze the secondary hydrolysis polycondensation reaction to obtain hybrid hydrophobic SiO2 mesoporous microspheres.

2. The method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes according to claim 1, characterized in that, The specific preparation process of the hybrid hydrophobic SiO2 mesoporous microspheres is as follows: (1) Obtaining of prepolymer: Tetraethyl orthosilicate and n-octyltrimethoxysilane are added to ethanol, stirred and mixed evenly, hydrochloric acid is added, and stirring and rotary evaporation under reduced pressure are continued to obtain a prepolymer; (2) Preparation of hybrid silica microspheres: A surfactant and a co-surfactant are dissolved in water and isopropanol as a continuous phase. The prepolymer prepared in step (1) is weighed and added to the continuous phase under stirring to form an O / W emulsion, and ammonia water is added to catalyze the secondary hydrolysis polycondensation reaction to obtain hybrid silica microspheres; (3) Post-treatment of hybrid silica microspheres: The hybrid silica microspheres prepared in step (2) are pore-expanded. After the reaction solution is added with water and allowed to stand, the supernatant is poured off, filtered, washed successively with deionized water and ethanol and then dried; Distilled water is added to the dried hybrid silica microspheres and stirred to disperse, and then ammonia water is added and stirred to react to obtain hybrid porous spherical silica, that is, the hybrid hydrophobic SiO2 mesoporous microspheres.

3. The method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes according to claim 1 or 2, characterized in that, The molar ratio of tetraethyl orthosilicate to n-octyltrimethoxysilane is 1:1 - 9:1; The surfactant is one of Triton-100, Span 80, Span 20, polyethylene glycol 200, and the addition amount of the surfactant is 2.0 - 8.0% of the mass of the prepolymer; The co-surfactant is one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, ionic liquid, and the addition amount of the co-surfactant is 0.1 - 1.0% of the mass of the prepolymer; The concentration of ammonia water is 25 - 28%, and the added volume of ammonia water accounts for 1 - 5% of the whole reaction system.

4. The method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes according to claim 2, characterized in that, The drying temperature is 50 - 60 °C, and the drying time is 12 - 24 h; Ammonia water is added in a mass-volume ratio of SiO2:NH3 of 10:

1.

5. The method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes according to claim 1, characterized in that, The size of the hybrid hydrophobic SiO2 mesoporous microspheres is 2-20 μm, the mesopore diameter is 4-16 nm, and the contact angle is 110-130 o .

6. The method for preparing healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes according to claim 1, characterized in that, The immobilization amount of the immobilized lipase is 50 - 250 mg / g, and the immobilization rate is 50 - 85%.

7. The method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes according to claim 1, characterized in that, The specific process for preparing immobilized lipase by physical adsorption is as follows: Free enzyme is added to phosphate buffer solution to prepare an enzyme solution, and the enzyme solution is mixed with a hydrophobic carrier for immobilization to obtain immobilized lipase; Among them, The pH value of the enzyme solution is 5.0 - 10.0, and the concentration is 10 - 100 mg / mL; the ratio of the mass of the hydrophobic carrier to the volume of the enzyme solution is 1:100 - 3.5:100 (m / v, g / mL); the immobilization time is 0.5 - 2 h, and the incubation temperature is 20 - 40 °C; the pH value of the phosphate buffer solution is 5.0 - 10.0; The free enzyme is one or a combination of phospholipase A1, Candida antarctica lipase, Rhizomucor miehei lipase, Pseudomonas cepacia lipase, Aspergillus niger lipase, Candida rugosa lipase.

8. The method for preparing a healthy edible oil rich in diglycerides by enzymatic glycerolysis and esterification using immobilized enzymes according to claim 1, characterized in that, In the step (2), the molar ratio of the raw material oil to glycerol is 1:3 - 3:1; the addition amount of the immobilized lipase is 1 - 5% of the substrate mass; the addition amount of water is 1 - 5% of the substrate mass; the temperature of the constant temperature water bath is 40 - 80 °C; the glycerolysis reaction time is 1 - 6 h; Moreover, deacidification is carried out by molecular distillation; the feeding rate of the molecular distillation is 2 - 10 mL / min, the distillation pressure is 10 - 50 Pa, the heating temperature is 170 - 200 °C, and the scraper rotation speed is 250 - 300 r / min; The raw material oil is one or a combination of rapeseed oil, linseed oil, soybean oil, corn oil, peanut oil, sesame oil, rice bran oil, sunflower oil, camellia seed oil, Xanthoceras sorbifolia Bunge oil, Acer truncatum Bunge oil, Malania oleifera Chun ex S. Lee oil, algal oil and fish oil rich in DHA, EPA, and ARA.

9. A healthy edible oil product rich in diglycerides prepared by the method according to any one of claims 1-8, characterized in that, The quality of the healthy edible oil product rich in diglyceride is as follows: The acid value is between 0.10 - 1.5 mg KOH / g, the peroxide value is 0.10 - 0.15 g / 100 g, the DAG content is 40 - 80%, and sn-1,3:sn-1,2 = 9:1 - 2:1; the functional fatty acids contained include one or a combination of oleic acid, linoleic acid, linolenic acid, DHA, ARA, EPA, and nervonic acid.

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