A method for preparing diglyceride oil

Abstract

The invention discloses a method for preparing diglyceride oil, which uses glycerol and vegetable oil as reactants, uses immobilized lipase TL IM (the dosage is 3-10% of the weight of the vegetable oil) as a catalyst at a temperature of 50-70°C, and uses water (the addition amount is 4-8‰ of the weight of the vegetable oil) as a medium to promote the mixing of the reactants. The reaction is completed by enzyme reactor reaction, multi-effect mixer mixing and pump transportation, and the cycle reaction is completed for at least 12 hours. The reaction product is further separated and removed from by-products (free fatty acids, monoglycerides) and reactants (glycerol, triglycerides) through a short-path distiller, and then deodorized and adsorbed to obtain a diglyceride oil product. The diglyceride content in the diglyceride oil product can reach more than 90%.

Description

Technical Field

[0001] The invention belongs to the technical field of oil modification, and particularly relates to a method for preparing diglyceride oil. Background Art

[0002] Diacylceride is a natural component of oils and fats. Its appearance (transparency, color), taste and flavor are no different from ordinary edible vegetable oils. Diacylceride is the product obtained by esterification of glycerol (glycerol) with two fatty acids, referred to as diglyceride and diglyceride, abbreviated as DG and DAG. It can be divided into two isomers, 1,2-DAG and 1,3-DAG, according to the different binding positions of the acyl group and the glycerol hydroxyl group.

[0003] Table 1 Quality requirements for diglyceride oil

[0004] Characteristics Transparent liquid Diacylceride Content ≥40％ Triglyceride content ≤58％ Monoglyceride content ≤1.5％ Free fatty acid content ≤0.5％

[0005] Tea seed oil, salt algae and extracts, fish oil and extracts, diglyceride oil, earthworm protein, milk mineral salt, and milk alkaline protein are new resource foods. The quality requirements of diglyceride oil are shown in Table 1. As a new generation of functional oils and fats, diglyceride oil has been widely used in the fields of food, medicine, and cosmetics. With the continuous in-depth research on diglyceride oil, its unique physiological activity in inhibiting obesity, cardiovascular, hypertension and other diseases has also been recognized. Studies have shown that diglyceride has the functions of regulating blood lipids, preventing arterial thrombosis, inhibiting liver fat accumulation, alleviating diabetic nephropathy, losing weight, and suppressing appetite.

[0006] At present, chemical catalysis and lipase catalysis are widely used in the industry to synthesize diglycerides.

[0007] The chemical catalytic method has the advantages of low cost and easy industrial application, but the reaction usually requires solvents, which is easy to cause environmental pollution and requires higher level equipment and workshops (usually explosion-proof). In addition, the chemical method has a high temperature, which will affect the quality of the final product (such as dark color, production of harmful components such as glycidyl esters, etc.).

[0008] There are two types of commercially available lipases: liquid enzymes and immobilized enzymes. Liquid lipases are very expensive and difficult to promote industrially. Relatively speaking, immobilized lipases are reusable, which greatly reduces production costs and has good market prospects.

[0009] Wang Yifan and others used low-temperature chemical glycerol decomposition to prepare 1,3-DAG. Under the optimal conditions of "solvent to reactant mass ratio 2:1 (acetone as solvent), catalyst dosage 0.6% (based on reactant mass, sodium methoxide as catalyst), reaction temperature 50°C, reaction time 3h", the triglyceride (TAG) content in the product was 44.03%, and the DAG content reached 43.97%, of which the 1,2-DAG content was 13.53%, and the 1,3-DAG content was 30.44%; when the amount of reactants was increased by 10 times, the TAG content in the product was 46.35%, and the 1,3-DAG content was 29.13%. However, it uses the organic solvent acetone, which is easy to cause environmental pollution and requires a higher level of equipment and workshops (usually explosion-proof).

[0010] Among the diglyceride oil products currently on the market, products with a diglyceride content of 20% are dominant, followed by products with a diglyceride content of 40%, while products with a diglyceride content of 80% are rare.

[0011] CN104388483A discloses a method for preparing diglyceride by solvent-free continuous enzymolysis. However, after reading the full text, the inventor found that there are many problems, which lead to doubts about its authenticity: First, according to common knowledge, the principle of molecular distillation is based on the difference in the mean free path of molecular motion of different molecules in the material to be separated under high vacuum conditions to achieve separation. In the inventor's many years of molecular distillation experimental experience, although the mean free path of molecular motion cannot be directly measured, the separation of different substances in the mixed material is closely related to its molecular weight. Generally, the larger the molecular weight, the higher the boiling point under the same vacuum conditions. Generally, the molecular weight of the light phase is less than that of the heavy phase. The molecular weight of glycerol is 92, the molecular weight of diglyceride is about 620, and the molecular weight of triglyceride is about 880. In the inventor's practice, under the same vacuum conditions, among the three substances, glycerol has the lowest boiling point, followed by diglyceride, and triglyceride has the highest boiling point. Specifically for the operation of separating the crude diglyceride mixture, the inventors found that the first stage molecular distillation is required to remove glycerol (light phase) first, and the heavy phase is diglyceride and triglyceride; the heavy phase of the first stage is then subjected to the second stage molecular distillation to purify diglyceride (light phase) and remove triglyceride (heavy phase). However, paragraph

[0020] of CN104388483A discloses that "the reaction product is separated by molecular distillation, and triglyceride and glycerol are directly removed by primary distillation, and the distillation temperature is 210°C. The light phase obtained by molecular distillation is a diglyceride product with a purity of 85%". That is, triglyceride and glycerol exist in the heavy phase at the same time, and the light phase is diglyceride. The inventor has never encountered this in his long-term practice, and it is not in line with scientific laws. The inventors question its authenticity. Secondly, in paragraph

[0020] of CN104388483A, regarding the process parameters of molecular distillation, only the temperature parameter "210°C" of the primary distillation is disclosed, and the vacuum degree parameter is not disclosed. According to common knowledge, the boiling point of the same substance is different under different vacuum conditions. It is well known that the boiling point of water in plains and plateaus can differ by 20 to 30 degrees. Those skilled in the art do not know how to directly remove triglycerides and glycerol by primary distillation at 210°C, and the relevant content is not disclosed by common knowledge. Third, taking Example 1 as an example, regarding the amount of enzyme used, only the loading amount "0.2g / cm 3 , 0.3g / cm 3 , 0.1g / cm 3"," and "the height-to-diameter ratio is 5-8", and the specific size of the selected glass column (for loading the immobilized lipase) is not disclosed. Without the specific volume value of the glass column, it is impossible to determine the specific amount of lipase. In the case of unknown specific amount of lipase, it is unknown whether the "purity of the crude diglyceride product in the effluent from the bottom of the immobilized lipase glass column after the enzymatic hydrolysis reaction in Examples 1-3 reaches 65-70%" disclosed in CN104388483A is obtained when the amount of lipase is low or when the amount of lipase is extremely high. According to common knowledge, an increase in the amount of lipase is usually beneficial to improving the purity of the crude diglyceride product. Therefore, the higher purity of the crude diglyceride product of CN104388483A is likely to be achieved by a high amount of lipase. In summary, as can be seen from the above analysis, there are unreasonable aspects in the technical solution of CN104388483A, and the lack of key process parameters leads to doubts about its authenticity and does not have any reference significance. Summary of the invention

[0012] [Technical issues]

[0013] The diglyceride content in the diglyceride oil products produced by the existing technology is relatively low (among the diglyceride oil products currently on the market, products with a diglyceride content of 20% dominate, followed by products with a diglyceride content of 40%, and products with a diglyceride content of more than 80% are rare); liquid enzyme preparations are expensive, and the cost of using them in the production of diglyceride oil is extremely high; adding solvents for the reaction has potential food safety hazards (solvent residues can lead to related food safety issues), and higher safety performance requirements are placed on the production equipment (explosion-proof production equipment is required).

[0014] [Technical solution]

[0015] In order to solve the above problems, the present invention uses glycerol and vegetable oil as reactants, uses immobilized lipase TL IM as a catalyst, and uses water as a medium to promote the mixing of reactants. The reaction is completed by enzyme reactor reaction, multi-effect mixer mixing, and pump transportation. The reaction product is further separated and removed by-products (free fatty acids, monoglycerides) and reactants (glycerol, triglycerides) through a short-path distiller, and then deodorized and adsorbed to obtain a diglyceride oil product.

[0016] In one aspect, a method for preparing diglyceride oil is provided, comprising the steps of:

[0017] Immobilized enzyme alcoholysis reaction: glycerol, vegetable oil and water are heated and stirred, and after being fully mixed in a multi-effect mixer, they are transported to an enzyme reactor filled with immobilized lipase, and cyclically reacted at 50-70° C. for at least 12 hours to obtain crude diglycerol oil; wherein the weight ratio of vegetable oil: glycerol: water: immobilized lipase is 100: (6-8): (0.4-0.8): (3-10); the immobilized lipase comprises: at least one of immobilized lipase Lipozyme TL IM or immobilized lipase Lipozyme RMIM; wherein the diglyceride content in the crude diglycerol oil is not less than 30%;

[0018] Primary purification: heating the crude diglyceride oil to 180-210° C., and distilling to remove water, free fatty acids, glycerol, and monoglyceride under a vacuum degree of 1-30 Pa to obtain a crude diglyceride oil product 1;

[0019] Secondary purification: heating the crude diglyceride oil product 1 to 280-305° C., and removing triglycerides by distillation under a vacuum degree of 1-15 Pa to obtain a crude diglyceride oil product 2 rich in diglycerides;

[0020] Deodorization: the crude diglyceride oil product 2 is subjected to a deodorization tower to remove odor components at a temperature of 170-220° C., a vacuum degree of 100-500 Pa, and a water vapor dosage of 1-3% by weight of the crude diglyceride oil product 2, to obtain a crude diglyceride oil product 2 from which odor components have been removed;

[0021] Adsorption: The crude diglyceride oil product 2 from which the odor components are removed is stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent amount of 1 to 5% by weight of the crude diglyceride oil product 2 from which the odor components are removed, and the adsorbent is removed by filtration to obtain a diglyceride oil product 2; the diglyceride content in the diglyceride oil product 2 is not less than 90%.

[0022] In some embodiments, the immobilized lipase is immobilized lipase Lipozyme TL IM.

[0023] In some embodiments, the weight ratio of vegetable oil: glycerol: water: immobilized lipase is 100: (6-7): (0.7-0.8): (3-5), and the reaction is cyclically reacted at 60-70° C. for 24-1200 hours; the diglyceride content in the crude diglyceride oil is not less than 32%.

[0024] In some embodiments, the weight ratio of vegetable oil: glycerol: water: immobilized lipase is 100: 6.2: (0.7-0.8): (3-5), and the reaction is cyclically carried out at 65°C for 24 hours; the content of diglycerides in the crude diglyceride oil is not less than 37%; the parameters of the first purification are: 195-205°C, vacuum degree 1-15 Pa; the parameters of the second purification are: 285-295°C, vacuum degree 1-5 Pa; the content of diglycerides in the diglyceride oil product 2 is not less than 96%.

[0025] In some embodiments, the amount of the adsorbent used is 1.5-3% by weight of the crude diglyceride oil product 2 from which the odor components are removed.

[0026] In some embodiments, the vegetable oil includes one or more of rice oil, corn oil, peanut oil, rapeseed oil, soybean oil, sunflower oil or camellia oil.

[0027] In some embodiments, the enzyme reactor is equipped with a pump, and the material flowing out from the top of the enzyme reactor is transported to the multi-effect mixer via the pump for full mixing, and then enters the bottom inlet of the enzyme reactor to fully circulate the reaction mixture.

[0028] In some embodiments, the adsorbent is one or more of activated clay, activated carbon or silica gel.

[0029] On the other hand, there is provided a diglyceride oil having a diglyceride content of not less than 90% obtained by the aforementioned method.

[0030] In another aspect, there is provided a use of the aforementioned diglyceride oil having a content of not less than 90% in one of the fields of food, medicine or cosmetics.

[0031] [Beneficial Effects]

[0032] 1. The present invention provides a method for preparing diacylglycerol oil, comprising the following steps: immobilized enzyme alcoholysis reaction: heating and stirring glycerol, vegetable oil and water, and after being fully mixed in a multi-effect mixer, conveying them to an enzyme reactor filled with immobilized lipase, and carrying out a cyclic reaction at 50-70° C. for at least 12 hours to obtain crude diacylglycerol oil; wherein the weight ratio of vegetable oil: glycerol: water: immobilized lipase is 100: (6-8): (0.4-0.8): (3-10); the immobilized lipase comprises: immobilized lipase Lipozyme TL IM or immobilized lipase Lipozyme RM IM at least one; wherein the content of diglyceride in the crude diglyceride oil is not less than 30%; primary purification: heating the crude diglyceride oil to 180-210°C, distilling off water, free fatty acids, glycerol and monoglyceride under a vacuum degree of 1-30 Pa to obtain a crude diglyceride oil product 1; secondary purification: heating the crude diglyceride oil product 1 to 280-305°C, distilling off triglyceride under a vacuum degree of 1-15 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride; deodorization: distilling the crude diglyceride oil product 2 at a temperature of 170-220 ℃, vacuum degree 100-500 Pa, and water vapor dosage 1-3% by weight of the crude diglyceride oil product 2, removing odor components through a deodorizing tower to obtain a crude diglyceride oil product 2 with odor components removed; adsorption: the crude diglyceride oil product 2 with odor components removed is stirred for 20-40 minutes at a temperature of 80-110℃, a vacuum degree of 100-400 Pa, and an adsorbent dosage of 1-5% by weight of the crude diglyceride oil product 2 for removing odor components, and filtering to remove the adsorbent to obtain a diglyceride oil product 2; the diglyceride content in the diglyceride oil product 2 is not less than 90%. The present invention selects specific immobilized lipase, optimizes the weight ratio of vegetable oil: glycerol: water: immobilized lipase, reaction temperature, reaction time, and purification process, and separates and removes byproducts (free fatty acids, monoglycerides) and reactants (glycerol, triglycerides) through a short-path distiller and further purifies, so that the diglyceride content in the diglyceride oil product can reach 90% or more, and can reach up to 97.06% at the highest; in the process of the immobilized lipase catalytic reaction in the present invention, the reaction mixture is mixed more fully after passing through a multi-effect mixer, and the conversion rate of diglycerides is significantly improved;

[0033] 2. The present invention has found through research that the immobilized lipase TL IM has high activity, good stability, and a long service life. It can achieve the production of high-purity diglyceride oil at a relatively low dosage, which can significantly reduce the production cost;

[0034] 3. The present invention can produce products of different specifications by controlling the process parameters and the number of distillations of short-path distillation. After the products are mixed in proportion, a series of products with a diglyceride content of 40 to 97% can be obtained, which can meet the different needs of the market; in particular, the present invention develops a method for preparing diglyceride oil with a diglyceride content of not less than 90%. The preparation method of diglyceride with such a high content has not been disclosed before and is a major technical problem in this field. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 Schematic diagram of the device used for preparing diglyceride oil in the present invention. DETAILED DESCRIPTION

[0036] The content of diglycerides was determined by high performance liquid chromatography (chromatographic column: silica gel column, 5 μm, 2.0×250 mm; column temperature: 35°C; flow rate: 0.3 mL / min), mobile phase A (n-hexane: isopropanol = 99:1, v / v), mobile phase B (n-hexane: isopropanol: glacial acetic acid = 1:1:0.1, v / v / v). The gradient elution parameters are as follows:

[0037]

[0038] Information about the immobilized lipase used in the embodiment of the present invention: The immobilized lipase TL IM is produced by Novozymes TL IM.

[0039] TL IM is a microbially produced, 1,3 position specific, food grade lipase (EC 3.1.1.3) on particulate silica gel, obtained from Thermomyces lanuginosus and produced by submerged fermentation using a genetically modified Aspergillus oryzae microorganism.

[0040] Product Features:

[0041] Catalytic activity: 250IUN / g;

[0042] Bulk density: 0.54 g / mL;

[0043] Particle diameter: 0.3~1.0mm;

[0044] Water content: 5% by weight;

[0045] 1 IUN is defined as the initial rate of conversion of 0.01% (by weight) of triglyceride of stearic acid per minute under the following batch transesterification conditions:

[0046] Base: Extremely hydrogenated soybean oil and soybeans are mixed in a weight ratio of 27:73;

[0047] Temperature: 70℃;

[0048] Auxiliary solvent: None;

[0049] Enzyme addition amount: 10% by weight.

[0050] Example 1

[0051] like Figure 1 As shown, in a water bath of 65 ℃ and under stirring, glycerine with an oil weight of 5.2% and water with an oil weight of 8‰ are added to the rice oil, the rice oil, glycerine and water are all metered by a quantitative pump and enter a mixing tank, after fully stirring (conventional paddle stirring for 20 to 30 minutes), they are transported to a multiple-effect mixer by a pump, the materials are fully mixed by the multiple-effect mixer, and then enter the enzyme reactor through the bottom inlet of the enzyme reactor, the enzyme reactor is filled with immobilized lipase TL IM, the filling amount is 3% of the weight of the rice oil, the timing is started when the materials flow out from the top of the enzyme reactor, the materials flowing out from the top of the enzyme reactor are returned to the mixing tank, under stirring, they are transported to the multiple-effect mixer by a pump, after fully mixing in the multiple-effect mixer, they enter the enzyme reactor through the bottom inlet of the enzyme reactor again, the reaction mixture is fully circulated, and after reacting for 12 hours, the reaction product is crude diglycerol oil, the materials flowing out from the top of the enzyme reactor enter the crude diglycerol oil storage tank, and the reaction product retained in the enzyme reactor is transported to the crude diglycerol oil storage tank by a pump. The diacylglycerol content of the crude diacylglycerol oil was found to be 15.88%;

[0052] The crude diglyceride oil is heated to 200-210°C, and water, free fatty acids, glycerol and monoglyceride are removed by short-path distiller under vacuum degree of 1-25 Pa to obtain a crude diglyceride oil product 1; the crude diglyceride oil product 1 is heated to 280-290°C, and triglyceride is removed by short-path distiller under vacuum degree of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride; the crude diglyceride oil product 2 is heated to 170-220°C, and vacuum degree of 100 ~500 Pa, the amount of water vapor is 1-3% of the weight of the crude diglyceride product 2, and the odor components are removed through a deodorizing tower to obtain a crude diglyceride oil product 2 with the odor components removed; the crude diglyceride oil product 2 with the odor components removed is stirred for 20-40 minutes at a temperature of 80-110°C, a vacuum degree of 100-400 Pa, and the amount of adsorbent activated white clay is 1% of the weight of the crude diglyceride oil product 2 with the odor components removed, and the adsorbent is removed by filtration to obtain a diglyceride oil product 2. After testing, the diglyceride oil product 2 has: 27.58% of 1,3-diglyceride, 22.47% of 1,2-diglyceride, and a total content of 50.05% of diglyceride.

[0053] The deodorization of oils and fats is a process of removing the odor components in oils and fats by steam distillation under high temperature and high vacuum conditions, based on the different volatility of odor components and triglycerides under the same conditions. The principle of steam deodorization is that water vapor passes through oils and fats containing flavor components, and the vapor-liquid contact causes the water vapor to be saturated with the volatile odor components and escapes and is removed according to their partial pressure ratio.

[0054] The calculation formula of steam volume is: Q = 3600 × P × V / ρ. Q represents the steam volume in kg / h, P represents the steam pressure in MPa, and V represents the steam flow in m 3 / h, ρ represents the density of steam, the unit is kg / m 3 .

[0055] The multi-effect mixer is an innovative continuous double-chamber mixing device designed on the basis of absorbing multi-layer high-speed stirring technology. The upper chamber of the product is a dispersing chamber, and the lower chamber is a mixing chamber. The dispersing and mixing chambers are designed as one, and the dispersing and mixing are carried out continuously and synchronously. The multi-effect mixer is mainly used to refine the droplets of the dispersed phase when mixing immiscible media to obtain a uniform dispersed phase, increase the contact area between the phases, and lay the foundation for the next chemical reaction.

[0056] Working principle of multi-effect mixer: The stirring blades of the multi-effect mixer adopt propulsion blades. The blades rotate under the drive of the stirring shaft, pushing out the fluid in the blade area and doing work. The fluid generates a certain pressure head under the push of the blades. Due to the effect of the baffles around the tank, the liquid forms an axial up and down circulation flow. In order to achieve the purpose of strong stirring, the multi-effect mixer is designed with a multi-layer stirring structure. Due to the different directions of the stirring blades on each layer, a high-turbulence and fully mixed zone is formed around the blades.

[0057] Comparative Example 1

[0058] Under 65 ℃ of water baths and under stirring, add glycerine with 5.2% oil weight in rice oil, do not add water, rice oil and glycerine are all metered by quantitative pumps and enter in the mixing tank, fully stir (conventional paddle stirring for 20~30 minutes), then be pumped to the multiple-effect mixer, after the material is fully mixed by the multiple-effect mixer, enter the enzyme reactor through the enzyme reactor bottom inlet, fill immobilized lipase TL IM in the enzyme reactor, the filling amount is 3% of rice oil weight, and the timing starts when the material flows out from the enzyme reactor top. The material flowing out from the enzyme reactor top is returned to the mixing tank, under stirring, is pumped to the multiple-effect mixer, after the multiple-effect mixer is fully mixed, enters the enzyme reactor through the enzyme reactor bottom inlet again, and the reaction mixture is fully circulated. After reacting for 12 hours, the reaction product is crude diglyceride oil, and the material flowing out from the enzyme reactor top enters the crude diglyceride oil storage tank, and the reaction product retained in the enzyme reactor is pumped to the crude diglyceride oil storage tank. After testing, the crude diglyceride oil contained 93.24% triglyceride and 6.76% 1,3-diglyceride. Compared with Example 1, without adding water, the content of 1,3-diglyceride in the reaction product dropped sharply from 15.88% in Example 1 to 6.76%. It can be seen that the presence of water significantly improved the mixing effect of the reactants and further improved the conversion rate.

[0059] Comparative Example 2

[0060] Under 65 ℃ of water baths and under stirring, add glycerine with oil weight 5.2% and water with oil weight 8‰ in rice oil, rice oil, glycerine and water are all metered by quantitative pumps and enter in the mixing tank, after fully stirring (conventional paddle stirring for 20~30 minutes), pump is delivered to the bottom inlet of enzyme reactor, enters enzyme reactor, fills immobilized lipase TL IM in the enzyme reactor, and the filling amount is 3% of rice oil weight, and timing is started when material flows out from the top of enzyme reactor, and the material flowing out from the top of enzyme reactor returns to the mixing tank, under stirring, pump is delivered to the bottom inlet of enzyme reactor, enters enzyme reactor, and the reaction mixture is fully circulated, after reacting for 12 hours, the reaction product is crude diglycerol oil, and the material flowing out from the top of enzyme reactor enters the crude diglycerol oil storage tank, and the reaction product retained in the enzyme reactor is delivered to the crude diglycerol oil storage tank by pump. After testing, the diglyceride content in the crude diglycerol oil is 8.62%. Compared with Example 1, without using a multi-effect mixer, the content of 1,3-diglyceride in the reaction product is sharply reduced from 15.88% in Example 1 to 8.62%. It can be seen that the presence of the multi-effect mixer significantly improves the mixing effect of the reactants and further improves the conversion rate of diglyceride.

[0061] Example 2

[0062] Under 65 ℃ of water bath and stirring, add glycerine with oil weight of 5.2% and water with oil weight of 8‰ in rice oil, rice oil, glycerine and water are all metered by quantitative pump and enter into mixing tank, after fully stirring (conventional paddle stirring for 20~30 minutes), pump is delivered to multi-effect mixer, after material is fully mixed by multi-effect mixer, enters enzyme reactor through the bottom inlet of enzyme reactor, fills immobilized lipase TL IM in enzyme reactor, and the filling amount is 3% of rice oil weight, and timing starts when material flows out from the top of enzyme reactor. Material flowing out from the top of enzyme reactor returns to mixing tank, under stirring, pump is delivered to multi-effect mixer, after fully mixing by multi-effect mixer, enters enzyme reactor through the bottom inlet of enzyme reactor again, makes reaction mixture fully circulate. After reacting for 10 hours, reaction product is crude diglycerol oil, material flowing out from the top of enzyme reactor enters crude diglycerol oil storage tank, and reaction product retained in enzyme reactor is pumped to crude diglycerol oil storage tank. After testing, the crude diglyceride oil contained: triglyceride 88.73%, 1,3-diglyceride 11.27%.

[0063] Compared with Comparative Example 1, after adding 8‰ water by weight of oil, although the reaction time was shortened by 2 hours, the content of 1,3-diglyceride in the reaction product was significantly increased from 6.76% to 11.27%. It can be seen that the presence of water significantly improved the mixing effect of the reactants and further increased the conversion rate of diglyceride.

[0064] Example 3

[0065] Under 65 ℃ of water bath and stirring, add glycerine with oil weight of 5.2% and water with oil weight of 8‰ in rice oil, rice oil, glycerine and water are all metered by quantitative pump and enter into mixing tank, after fully stirring (conventional paddle stirring for 20~30 minutes), pump is delivered to multi-effect mixer, after material is fully mixed by multi-effect mixer, enters enzyme reactor through the bottom inlet of enzyme reactor, fills immobilized lipase TL IM in enzyme reactor, and the filling amount is 3% of rice oil weight, and timing starts when material flows out from the top of enzyme reactor. Material flowing out from the top of enzyme reactor returns to mixing tank, under stirring, pump is delivered to multi-effect mixer, after fully mixing by multi-effect mixer, enters enzyme reactor through the bottom inlet of enzyme reactor again, makes reaction mixture fully circulate. After reacting for 24 hours, reaction product is crude diglycerol oil, material flowing out from the top of enzyme reactor enters crude diglycerol oil storage tank, and the reaction product retained in enzyme reactor is pumped to crude diglycerol oil storage tank. The crude diglyceride oil contained 14.77% 1,3-diglyceride and 12.37% 1,2-diglyceride, and the total content of diglyceride was 27.14%.

[0066] The crude diglyceride oil is heated to 195-205°C, and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum of 1-15 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 285-295°C, and triglycerides are removed by distillation in a short-path distiller under a vacuum of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220°C, a vacuum of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 from which the odor components are removed are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent activated carbon dosage of 2% of the weight of the diglyceride oil crude product 1 and the diglyceride oil crude product 2 from which the odor components are removed, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 16.21% of 1,3-diglyceride, 13.58% of 1,2-diglyceride, and the total content of diglyceride is 29.79%; the diglyceride oil product 2 contains 47.12% of 1,3-diglyceride, 34.16% of 1,2-diglyceride, and the total content of diglyceride is 81.28%.

[0067] Example 4

[0068] Under 65 ℃ of water bath and stirring, add glycerine with oil weight of 6.2% and water with oil weight of 8‰ in rice oil, rice oil, glycerine and water are all metered by quantitative pump and enter into mixing tank, after fully stirring (conventional paddle stirring for 20~30 minutes), pump is delivered to multi-effect mixer, after material is fully mixed by multi-effect mixer, enters enzyme reactor through the bottom inlet of enzyme reactor, fills immobilized lipase TL IM in enzyme reactor, and the filling amount is 3% of rice oil weight, and timing starts when material flows out from the top of enzyme reactor. Material flowing out from the top of enzyme reactor returns to mixing tank, under stirring, pump is delivered to multi-effect mixer, after fully mixing by multi-effect mixer, enters enzyme reactor through the bottom inlet of enzyme reactor again, makes reaction mixture fully circulate. After reacting for 12 hours, reaction product is crude diglycerol oil, material flowing out from the top of enzyme reactor enters crude diglycerol oil storage tank, and the reaction product retained in enzyme reactor is pumped to crude diglycerol oil storage tank. After testing, the crude diglyceride oil contained 65.23% triglyceride, 16.63% 1,3-diglyceride, and 14.16% 1,2-diglyceride, and the total content of diglyceride was 30.79%.

[0069] The crude diglyceride oil is heated to 195-205°C, and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum of 1-15 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 285-295°C, and triglycerides are removed by distillation in a short-path distiller under a vacuum of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220°C, a vacuum of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 from which the odor component is removed are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent silica gel dosage of 1% of the weight of the diglyceride oil crude product 1 and the diglyceride oil crude product 2 from which the odor component is removed, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 18.48% of 1,3-diglyceride, 15.73% of 1,2-diglyceride, and the total content of diglyceride is 34.21%; the diglyceride oil product 2 contains 48.11% of 1,3-diglyceride, 39.22% of 1,2-diglyceride, and the total content of diglyceride is 87.33%.

[0070] Example 5

[0071] Under 65 ℃ of water bath and stirring, add glycerine with oil weight of 6.2% and water with oil weight of 8‰ in rice oil, rice oil, glycerine and water are all metered by quantitative pump and enter into mixing tank, after fully stirring (conventional paddle stirring for 20~30 minutes), pump is delivered to multi-effect mixer, after material is fully mixed by multi-effect mixer, enters enzyme reactor through the bottom inlet of enzyme reactor, fills immobilized lipase TL IM in enzyme reactor, and the filling amount is 3% of rice oil weight, and timing starts when material flows out from the top of enzyme reactor. Material flowing out from the top of enzyme reactor returns to mixing tank, under stirring, pump is delivered to multi-effect mixer, after fully mixing by multi-effect mixer, enters enzyme reactor through the bottom inlet of enzyme reactor again, makes reaction mixture fully circulate. After reacting for 24 hours, reaction product is crude diglycerol oil, material flowing out from the top of enzyme reactor enters crude diglycerol oil storage tank, and the reaction product retained in enzyme reactor is pumped to crude diglycerol oil storage tank. After testing, the crude diglyceride oil contained: triglyceride 62.08%, 1,3-diglyceride 21.93%, 1,2-diglyceride 15.95%, and the total content of diglycerides was 37.88%.

[0072] The crude diglyceride oil is heated to 195-205°C, and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum of 1-15 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 285-295°C, and triglycerides are removed by distillation in a short-path distiller under a vacuum of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220°C, a vacuum of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent activated carbon dosage of 1.5% of the weight of the diglyceride oil crude product 2 for removing the odor component, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 24.11% of 1,3-diglyceride, 17.53% of 1,2-diglyceride, and the total content of diglyceride is 41.64%; the diglyceride oil product 2 contains 53.48% of 1,3-diglyceride, 43.58% of 1,2-diglyceride, and the total content of diglyceride is 97.06%.

[0073] In this embodiment, the total diglyceride content in the diglyceride product 2 is increased from the initial 37.88% to 97.06%, an increase of nearly 60%, which is a significant improvement over CN104388483A.

[0074] By mixing diglyceride oil product 1 and diglyceride oil product 2 in a specific ratio, diglyceride oil products of different specifications with diglyceride contents ranging from 45% to 90% can be obtained. The individual ratio data are shown in Table 1.

[0075] Table 1 Diacylglycerol oil products of different specifications

[0076]

[0077] Comparative Example 3 Comparison of different types of immobilized lipase

[0078] Refer to Example 5, the only difference is that the type of immobilized lipase is changed to immobilized lipase LipozymeRM IM or immobilized lipase Novozyme 435. After testing, the total content of diglycerides in the crude diglyceride oil catalyzed by immobilized lipase Lipozyme RM IM is 30.64%, and the total content of diglycerides in the crude diglyceride oil catalyzed by immobilized lipase Novozyme 435 is 28.34%. Under the same reaction conditions, the catalytic efficiency of immobilized lipase Lipozyme RMIM is only about 80% of that of immobilized lipase TL IM, and the catalytic efficiency of immobilized lipase Novozyme 435 is only about 75% of that of immobilized lipase TL IM.

[0079] Example 6 Stability test of immobilized lipase TL IM

[0080] Referring to Example 5, the reaction was carried out for 50 cycles, and the crude diglyceride oil of the reaction product of the 50th reaction cycle was taken for detection. After detection, the total content of diglyceride in the crude diglyceride oil was 32.54%. The catalytic efficiency of the immobilized lipase TL IM was still maintained at about 86%, and the stability was very good, which was suitable for large-scale production of diglyceride oil in factories.

[0081] Example 7

[0082] In a water bath at 70°C and under stirring, add glycerol with an oil weight of 7.8% and water with an oil weight of 6‰ to corn oil. The corn oil, glycerol and water are all metered by a quantitative pump and enter a mixing tank. After being fully stirred (conventional paddle stirring for 20 to 30 minutes), the materials are pumped to a multi-effect mixer. After being fully mixed by the multi-effect mixer, the materials enter the enzyme reactor through the bottom inlet of the enzyme reactor. The enzyme reactor is filled with immobilized lipase TL IM, and the filling amount is 6% of the weight of corn oil. The timing starts when the materials flow out from the top of the enzyme reactor. The materials flowing out from the top of the enzyme reactor are returned to the mixing tank, and under stirring, they are pumped to the multi-effect mixer. After being fully mixed by the multi-effect mixer, they enter the enzyme reactor through the bottom inlet of the enzyme reactor to fully circulate the reaction mixture. After reacting for 12 hours, the reaction product is crude diglycerol oil. The materials flowing out from the top of the enzyme reactor enter the crude diglycerol oil storage tank, and the reaction products retained in the enzyme reactor are pumped to the crude diglycerol oil storage tank. The crude diglyceride oil contained 66.36% triglyceride, 18.95% 1,3-diglyceride, and 14.69% 1,2-diglyceride, and the total content of diglyceride was 33.64%.

[0083] The crude diglyceride oil is heated to 200-210°C, and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum degree of 5-30 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 295-305°C, and triglycerides are removed by distillation in a short-path distiller under a vacuum degree of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220°C, a vacuum degree of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent of activated clay of 5% of the weight of the diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 21.29% of 1,3-diglyceride, 16.51% of 1,2-diglyceride, and the total content of diglyceride is 37.8%; the diglyceride oil product 2 contains 45.98% of 1,3-diglyceride, 37.47% of 1,2-diglyceride, and the total content of diglyceride is 83.45%.

[0084] Example 8

[0085] In a water bath at 55°C and under stirring, add glycerol with an oil weight of 7.8% and water with an oil weight of 5‰ to the peanut oil. The peanut oil, glycerol and water are all metered by a quantitative pump and enter the mixing tank. After sufficient stirring (conventional paddle stirring for 20 to 30 minutes), the materials are pumped to a multi-effect mixer. After being fully mixed by the multi-effect mixer, the materials enter the enzyme reactor through the bottom inlet of the enzyme reactor. The enzyme reactor is filled with immobilized lipase TL IM, and the filling amount is 8% of the weight of the peanut oil. The timing starts when the materials flow out from the top of the enzyme reactor. The materials flowing out from the top of the enzyme reactor are returned to the mixing tank. Under stirring, they are pumped to the multi-effect mixer. After being fully mixed by the multi-effect mixer, they enter the enzyme reactor through the bottom inlet of the enzyme reactor to fully circulate the reaction mixture. After reacting for 24 hours, the reaction product is crude diglycerol oil. The materials flowing out from the top of the enzyme reactor enter the crude diglycerol oil storage tank. The reaction products retained in the enzyme reactor are pumped to the crude diglycerol oil storage tank. The crude diglyceride oil contained 19.1% 1,3-diglyceride and 16.64% 1,2-diglyceride, and the total content of diglyceride was 35.74%.

[0086] The crude diglyceride oil is heated to 180-195°C, and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum degree of 1-10 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 280-290°C, and triglycerides are removed by distillation in a short-path distiller under a vacuum degree of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220°C, a vacuum degree of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent activated carbon dosage of 5% of the weight of the diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 20.76% of 1,3-diglyceride, 18.09% of 1,2-diglyceride, and the total content of diglyceride is 38.85%; the diglyceride oil product 2 contains 49.73% of 1,3-diglyceride, 40.52% of 1,2-diglyceride, and the total content of diglyceride is 90.25%.

[0087] Example 9

[0088] In a water bath at 50°C and under stirring, add 6.2% glycerol and 4‰ water of oil weight to rapeseed oil, rapeseed oil, glycerol and water are all metered by a quantitative pump and enter a mixing tank, fully stirred (conventional paddle stirring for 20 to 30 minutes), and then pumped to a multi-effect mixer, after fully mixed by the multi-effect mixer, the materials enter the enzyme reactor through the bottom inlet of the enzyme reactor, and the enzyme reactor is filled with immobilized lipase TL IM, the filling amount is 10% of the rapeseed oil weight, and the timing starts when the materials flow out from the top of the enzyme reactor. The materials flowing out from the top of the enzyme reactor are returned to the mixing tank, and under stirring, they are pumped to the multi-effect mixer, and after fully mixed by the multi-effect mixer, they enter the enzyme reactor through the bottom inlet of the enzyme reactor to fully circulate the reaction mixture. After reacting for 24 hours, the reaction product is crude diglycerol oil, and the materials flowing out from the top of the enzyme reactor enter the crude diglycerol oil storage tank, and the reaction products retained in the enzyme reactor are pumped to the crude diglycerol oil storage tank. The crude diglyceride oil contained 20.18% 1,3-diglyceride and 14.67% 1,2-diglyceride, and the total content of diglyceride was 34.85%.

[0089] The crude diglyceride oil is heated to 190-200° C., and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum degree of 1-20 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 285-295° C., and triglycerides are removed by distillation in a short-path distiller under a vacuum degree of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220° C., a vacuum degree of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent of activated clay of 3% of the weight of the diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 22.42% of 1,3-diglyceride, 16.32% of 1,2-diglyceride, and the total content of diglyceride is 38.74%; the diglyceride oil product 2 contains 49.21% of 1,3-diglyceride, 40.08% of 1,2-diglyceride, and the total content of diglyceride is 89.29%.

[0090] Example 10

[0091] In a water bath at 60°C and under stirring, add 6.2% glycerol and 1‰ water of oil weight to soybean oil, the soybean oil, glycerol and water are all metered by a quantitative pump and enter the mixing tank, after fully stirring (conventional paddle stirring for 20 to 30 minutes), the pump is transported to the multi-effect mixer, the materials are fully mixed by the multi-effect mixer, and enter the enzyme reactor through the bottom inlet of the enzyme reactor, the enzyme reactor is filled with immobilized lipase TL IM, the filling amount is 2% of the weight of soybean oil, and the timing starts when the material flows out from the top of the enzyme reactor. The material flowing out from the top of the enzyme reactor returns to the mixing tank, under stirring, it is transported to the multi-effect mixer by a pump, after being fully mixed by the multi-effect mixer, it enters the enzyme reactor through the bottom inlet of the enzyme reactor, so that the reaction mixture is fully circulated. After reacting for 24 hours, the reaction product is crude diglycerol oil, the material flowing out from the top of the enzyme reactor enters the crude diglycerol oil storage tank, and the reaction product retained in the enzyme reactor is transported to the crude diglycerol oil storage tank by a pump. The crude diglyceride oil contained 9.87% 1,3-diglyceride and 7.18% 1,2-diglyceride, and the total content of diglyceride was 17.05%.

[0092] The crude diglyceride oil is heated to 195-205° C., and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum degree of 1-15 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 285-295° C., and triglycerides are removed by distillation in a short-path distiller under a vacuum degree of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220° C., a vacuum degree of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent of activated clay of 5% of the weight of the diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 10.97% 1,3-diglyceride, 7.98% 1,2-diglyceride, and the total content of diglyceride is 18.95%; the diglyceride oil product 2 contains 29.51% 1,3-diglyceride, 24.04% 1,2-diglyceride, and the total content of diglyceride is 53.55%.

[0093] Embodiment 11

[0094] In a water bath at 65°C and under stirring, add glycerol with an oil weight of 6.2% and water with an oil weight of 7‰ to the sunflower oil. The sunflower oil, glycerol and water are all metered by a quantitative pump and enter a mixing tank. After being fully stirred (conventional paddle stirring for 20 to 30 minutes), the materials are pumped to a multi-effect mixer. After being fully mixed by the multi-effect mixer, the materials enter the enzyme reactor through the bottom inlet of the enzyme reactor. The enzyme reactor is filled with immobilized lipase TL IM, and the filling amount is 4% of the weight of the sunflower oil. The timing starts when the materials flow out from the top of the enzyme reactor. The materials flowing out from the top of the enzyme reactor are returned to the mixing tank. Under stirring, they are pumped to the multi-effect mixer. After being fully mixed by the multi-effect mixer, they enter the enzyme reactor through the bottom inlet of the enzyme reactor to fully circulate the reaction mixture. After reacting for 24 hours, the reaction product is crude diglycerol oil. The materials flowing out from the top of the enzyme reactor enter the crude diglycerol oil storage tank. The reaction products retained in the enzyme reactor are pumped to the crude diglycerol oil storage tank. The crude diglyceride oil contained 21.06% 1,3-diglyceride and 15.31% 1,2-diglyceride, and the total content of diglyceride was 36.37%.

[0095] The crude diglyceride oil is heated to 195-205° C., and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum degree of 1-15 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 285-295° C., and triglycerides are removed by distillation in a short-path distiller under a vacuum degree of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220° C., a vacuum degree of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 from which the odor component is removed are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent silica gel dosage of 2% of the weight of the diglyceride oil crude product 1 and the diglyceride oil crude product 2 from which the odor component is removed, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 24.14% of 1,3-diglyceride, 16.83% of 1,2-diglyceride, and the total content of diglyceride is 40.97%; the diglyceride oil product 2 contains 51.34% of 1,3-diglyceride, 41.83% of 1,2-diglyceride, and the total content of diglyceride is 93.17%.

[0096] Example 12

[0097] In a water bath at 65°C and under stirring, add glycerol with an oil weight of 6.2% and water with an oil weight of 7‰ to the camellia oil. The camellia oil, glycerol and water are all metered by a quantitative pump and enter a mixing tank. After being fully stirred (conventional paddle stirring for 20 to 30 minutes), the materials are pumped to a multi-effect mixer. After being fully mixed by the multi-effect mixer, the materials enter the enzyme reactor through the bottom inlet of the enzyme reactor. The enzyme reactor is filled with immobilized lipase TL IM, and the filling amount is 5% of the weight of the camellia oil. The timing starts when the materials flow out from the top of the enzyme reactor. The materials flowing out from the top of the enzyme reactor are returned to the mixing tank. Under stirring, they are pumped to the multi-effect mixer. After being fully mixed by the multi-effect mixer, they enter the enzyme reactor through the bottom inlet of the enzyme reactor to fully circulate the reaction mixture. After reacting for 24 hours, the reaction product is crude diglycerol oil. The materials flowing out from the top of the enzyme reactor enter the crude diglycerol oil storage tank. The reaction products retained in the enzyme reactor are pumped to the crude diglycerol oil storage tank. After testing, the crude diglyceride oil contained: 21.71% 1,3-diglyceride, 15.78% 1,2-diglyceride, and the total content of diglycerides was 37.49%.

[0098] The crude diglyceride oil is heated to 195-205° C., and water, free fatty acids, glycerol, and monoglyceride are removed by distillation in a short-path distiller under a vacuum degree of 1-15 Pa to obtain a crude diglyceride oil product 1. The diglyceride oil product 1 is heated to 285-295° C., and triglycerides are removed by distillation in a short-path distiller under a vacuum degree of 1-5 Pa to obtain a crude diglyceride oil product 2 rich in diglyceride. The crude diglyceride oil product 1 and the crude diglyceride oil product 2 are respectively subjected to a deodorization tower to remove odor components at a temperature of 170-220° C., a vacuum degree of 100-500 Pa, and a steam dosage of 1-3% of the weight of the crude diglyceride oil product 1 and the crude diglyceride oil product 2, respectively, to obtain a crude diglyceride oil product 1 and a crude diglyceride oil product 2 with odor components removed. The diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component are stirred for 20 to 40 minutes at a temperature of 80 to 110° C., a vacuum degree of 100 to 400 Pa, and an adsorbent of activated clay of 3% of the weight of the diglyceride oil crude product 1 and the diglyceride oil crude product 2 for removing the odor component, respectively, and the adsorbent is removed by filtration to obtain the diglyceride oil product 1 and the diglyceride oil product 2. After testing, the diglyceride oil product 1 contains 23.87% of 1,3-diglyceride, 17.35% of 1,2-diglyceride, and the total content of diglyceride is 41.22%; the diglyceride oil product 2 contains 52.94% of 1,3-diglyceride, 43.14% of 1,2-diglyceride, and the total content of diglyceride is 96.08%.

[0099] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing diglyceride oil, characterized in that: The steps include: Immobilized enzyme alcoholysis reaction: glycerol, vegetable oil and water are heated and stirred, and after being fully mixed in a multi-effect mixer, they are transported to an enzyme reactor filled with immobilized lipase, and cyclically reacted at 50-70°C for at least 24 hours to obtain crude diglycerol oil; wherein the weight ratio of vegetable oil: glycerol: water: immobilized lipase is 100: (6-8): (0.4-0.8): (3-10); the immobilized lipase is Lipozyme TL IM; wherein the diglyceride content in the crude diglycerol oil is not less than 30%; the vegetable oil includes one or more of rice oil, corn oil, peanut oil, rapeseed oil, soybean oil, sunflower seed oil or camellia oil; The enzyme reactor is equipped with a pump, and the material flowing out of the top of the enzyme reactor is transported to the multi-effect mixer via the pump for full mixing, and then enters the bottom inlet of the enzyme reactor, so that the reaction mixture is fully circulated; The upper chamber of the multi-effect mixer is a dispersion chamber, and the lower chamber is a mixing chamber, and the dispersion chamber and the mixing chamber are designed as one body; the stirring blades of the multi-effect mixer are pusher blades, and the blades rotate under the drive of the stirring shaft; it has a multi-layer stirring structure, and the stirring blades of each layer are arranged in different directions; Primary purification: heating the crude diglyceride oil to 180-210° C., and distilling to remove water, free fatty acids, glycerol, and monoglyceride under a vacuum degree of 1-30 Pa to obtain a crude diglyceride oil product 1; Secondary purification: heating the crude diglyceride oil product 1 to 280-305° C., and removing triglycerides by distillation under a vacuum degree of 1-15 Pa to obtain a crude diglyceride oil product 2 rich in diglycerides; Deodorization: the crude diglyceride oil product 2 is subjected to a deodorization tower to remove odor components at a temperature of 170-220°C, a vacuum degree of 100-500 Pa, and a water vapor dosage of 1-3% by weight of the crude diglyceride oil product 2, to obtain a crude diglyceride oil product 2 from which odor components have been removed; Adsorption: The crude diglyceride oil product 2 from which the odor components are removed is stirred for 20 to 40 minutes at a temperature of 80 to 110°C, a vacuum degree of 100 to 400 Pa, and an adsorbent amount of 1 to 5% by weight of the crude diglyceride oil product 2 from which the odor components are removed, and the adsorbent is removed by filtration to obtain a diglyceride oil product 2; the diglyceride content in the diglyceride oil product 2 is not less than 90%; the adsorbent is one or more of activated clay, activated carbon or silica gel.

2. The method according to claim 1, characterized in that The weight ratio of vegetable oil: glycerol: water: immobilized lipase is 100: (6-7): (0.7-0.8): (3-5), and the reaction is cyclically carried out at 60-70° C. for 24-1200 hours; the content of diglyceride in the crude diglyceride oil is not less than 32%.

3. The method according to claim 2, characterized in that The weight ratio of vegetable oil: glycerol: water: immobilized lipase is 100: 6.2: (0.7-0.8): (3-5), and the reaction is cyclically carried out at 65°C for 24 hours; the content of diglyceride in the crude diglyceride oil is not less than 37%; the parameters of the first purification are: 195-205°C, vacuum degree 1-15 Pa; the parameters of the second purification are: 285-295°C, vacuum degree 1-5 Pa; the content of diglyceride in the diglyceride oil product 2 is not less than 96%.

4. The method according to claim 3, characterized in that The amount of the adsorbent used is 1.5-3% by weight of the crude product of diglyceride oil from which the odor component is removed.

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