A method for the enzymatic preparation of a dairy product enriched in functional esters and products

Abstract

This invention discloses an enzymatic method for preparing dairy products rich in functional esters. The method involves mixing and dissolving triglycerides and an active polyhydroxy compound at 45-65°C, then adding an immobilized lipase and the dairy product for transesterification or esterification. Alternatively, the active polyhydroxy compound and whole-fat dairy product are mixed uniformly in a water bath at 45-65°C, an immobilized lipase is added, and after high-speed homogenization, esterification or transesterification occurs. After the reaction, the resulting solution is a semi-product of the functional ester-rich dairy product, which is then subjected to high-pressure homogenization to obtain the final product. This invention significantly improves the nutritional value and functional lipid content of milk and other dairy products without compromising their stability and nutritional components, and also offers advantages such as good storage stability.

Description

Technical Field

[0001] This invention belongs to the field of enzymatic modification and quality and function enhancement of dairy products, specifically relating to a method and product for synthesizing dairy products rich in functional lipids by using the natural emulsion interface system of dairy products for efficient enzymatic esterification or transesterification. Background Technology

[0002] Functional lipids are a class of oils with special physiological functions. Some of their unique nutrients or active substances have positive preventative and therapeutic effects on certain human diseases. The main active substances are polyunsaturated fatty acids: linoleic acid, alpha-linolenic acid, gamma-linolenic acid, arachidonic acid, eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA); phospholipids: lecithin, cephalin, inositol phospholipids, serine phospholipids, etc.; some oils also contain squalene, dietary fiber, vitamins, and minerals. However, the absorption rate of functional lipids from the diet is low, therefore, it is necessary to increase the intake of functional lipids through foods rich in functional lipids.

[0003] As is well known, milk is rich in nutrients and easily digested and absorbed, making it one of the most ideal natural foods. Most importantly, milk is rich in natural emulsifying and stabilizing components such as protein and fats, forming a natural, green food emulsion system. Studies have shown that consuming dairy products fortified with functional activities such as phytosterols can lower cholesterol levels. However, currently, functional lipids or active polyhydroxy compounds are directly added to dairy products, which is limited not only by the types of functional lipids but also by problems such as low addition amounts and poor solubility. There are no reports on a one-step enzymatic method for preparing dairy products rich in functional lipids from a natural emulsion system. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an enzymatic method for preparing dairy products rich in functional esters, which addresses the shortcomings of the prior art. This method greatly improves the nutritional value and functional activity of dairy products such as milk, while not destroying their stability and nutritional components, and has advantages such as good stability and storability.

[0005] The technical solution adopted by the present invention to solve the above-mentioned problems is as follows:

[0006] A method for preparing dairy products rich in functional lipids using an enzymatic process, characterized by comprising the following steps:

[0007] (1) The free enzyme was added to phosphate buffer to prepare an enzyme solution; then the enzyme solution was mixed with a SiO2 support modified with mixed groups, and the mixture was dried to prepare an immobilized lipase; wherein the SiO2 support is a silane coupling agent modified micron-sized hollow mesoporous SiO2 microsphere with a size of 3-5 μm, a mesopore size distribution between 10-20 nm, and a water contact angle of 45°-110°, which is beneficial to the mass and heat transfer of the reaction substrate in the system and the efficient immobilization of the enzyme;

[0008] (2) Mix and dissolve triglycerides and active polyhydroxy compounds at 45-65℃, add the immobilized lipase obtained in step (1) and dairy products, then homogenize or vigorously stir or shake for 1 minute to form a micron-sized emulsion and then carry out transesterification or esterification reaction; or, mix active polyhydroxy compounds and whole milk products evenly in a water bath at 45-65℃, add the immobilized lipase obtained in step (1), and carry out or vigorously stir or shake for 1 minute to form a micron-sized emulsion, and carry out esterification or transesterification reaction;

[0009] (3) After the reaction in step (2) is completed, the immobilized lipase is separated and reused. The resulting solution is the semi-product of the dairy product rich in functional esters. Then, the product is obtained by high-pressure homogenization.

[0010] According to the above scheme, in step (1), the free enzyme is one or more of the following: Candida pleurisy lipase, Candida pleurisy lipase, Candida antarcticis lipase, NS40086 lipase, Thermophilic Mycospora spp., and Candida lipolyticis lipase; the enzyme solution has a pH of 6.0-9.0 and a concentration of 30-200 mg / mL; the ratio of carrier mass to enzyme solution volume is 1:100-5:100 (m / v, g / mL); the immobilization time is 10-60 min and the temperature is 20-40℃; the pH of the phosphate buffer is 6.0-9.0.

[0011] According to the above scheme, the active polyhydroxy compound is one or more of the following in any proportion: vitamin A, vitamin A ethyl ester, vitamin C, vitamin C ethyl ester, tea polyphenols, tea polyphenol ethyl ester, rutin, resveratrol, resveratrol ethyl ester, chlorogenic acid, chlorogenic acid ethyl ester, etc.

[0012] According to the above scheme, the dairy product is a skimmed dairy product or a whole dairy product. Specifically, the skimmed dairy product is skimmed milk; the whole dairy product is one or more of the following in any proportion: whole milk, flaxseed milk, peanut milk, walnut milk, almond milk, soy milk, oat milk, etc.

[0013] According to the above scheme, in step (2), the molar ratio of the active polyhydroxy compound to the triglyceride is 1:4-1:14; the triglyceride is one or more of the following in any proportion: flaxseed oil, perilla oil, hemp seed oil, evening primrose oil, peony seed oil, sunflower seed oil, soybean oil, sunflower seed oil, conjugated linoleic acid glyceride, DHA algal oil, fish oil, garlic fruit oil, and *Sapindus mukorossi* oil.

[0014] According to the above scheme, in step (2), the amount of active polyhydroxy compound added is 0.5-10.0 mg / mL, and the amount of immobilized lipase added is 1-20 mg / mL relative to the dairy product; the transesterification or esterification reaction is carried out in a constant temperature water bath at 45-65℃; the emulsion particle size is between 80-110 μm, and the contact area is 690-950 cm². 2 / mL.

[0015] According to the above scheme, in step (2), the transesterification reaction time is 10-120 min; the esterification reaction time is 10-120 min.

[0016] According to the above scheme, in steps (2) and (3), the high-pressure homogenization is carried out by using a high-pressure homogenizer for 10-20 cycles, with a pressure of 400-600 Pa.

[0017] According to the above scheme, the immobilized lipase separated in step (3) can be reused after being washed with PBS and freeze-dried; the immobilized lipase can be reused 6 times, and the relative content of functional esters in the prepared oil products rich in functional esters will still remain above 70%.

[0018] The dairy products rich in functional lipids prepared by the above method have functional lipids accounting for 20%-60% of the mass of oil in the dairy products; the beneficial fatty acids contained include one or more of linolenic acid, nervonic acid, oleic acid, linoleic acid, DHA, EPA, ARA, etc., and the content of beneficial fatty acids in the functional esters is more than 53%; the diglyceride content is 0.1%-3%, and the content of generated functional esters reaches 0.5g-3.0g / 100mL.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. This invention addresses the problems of unreasonable fatty acid structure and lack of functional lipids in dairy products. It utilizes the naturally stable emulsion system of dairy products, employing immobilized lipases as both emulsifiers and catalysts to establish a green, efficient, and solvent-free emulsion interface catalytic system, enabling in-situ generation of dairy products rich in functional esters. The emulsion particle size is between 80-110 μm, and the contact area reaches 690-950 cm². 2 / mL; then, by adding different oils and active polyhydroxy compounds exogenously, they are efficiently converted into functional lipids at the emulsion interface.

[0021] 2. This invention efficiently synthesizes dairy products rich in functional lipids such as diglycerides by adding polyhydroxy compounds to the dairy product system via enzymatic method, which greatly improves the nutritional value and functional activity of milk, while not destroying the stability and nutritional components of milk itself, and also has good stability and storage properties.

[0022] 3. This invention can be widely used to catalyze the transesterification or esterification reaction of triglycerides and active polyhydroxy compounds. Different raw materials can be selected according to needs to prepare dairy products rich in functional esters. Flaxseed oil and vitamin C can be used to prepare vitamin C linolenic acid esters. The content of functional esters and fatty acid composition in the resulting dairy products rich in functional esters are controllable, and the products are diverse to meet the needs of different application scenarios.

[0023] 4. The reaction process of this invention uses a solvent-free emulsion enzyme catalysis system, which has mild reaction conditions, short reaction time, and simple separation; compared with traditional chemical catalysis methods, it does not produce by-products and waste; compared with non-aqueous enzyme catalysis methods, it does not require organic solvents and has a high product yield.

[0024] 5. The dairy products rich in functional lipids prepared by this invention have a diglyceride content of 0.1%-3%, and the generated functional lipids account for 0.5g-3.0g / 100mL of the dairy products; the functional lipids account for 20%-60% of the mass percentage of oil in the dairy products; the beneficial fatty acid content in the functional lipids is more than 53%, and the beneficial fatty acids include one or more of linolenic acid, nervonic acid, oleic acid, linoleic acid, DHA, EPA, and ARA. Attached Figure Description

[0025] Figure 1 The water contact angle of hollow mesoporous SiO2 microspheres modified with silane coupling agent.

[0026] Figure 2 The images show the pore size distribution of the hollow mesoporous SiO2 microspheres used in Examples 1-6 before and after modification with silane coupling agent.

[0027] Figure 3 This is a fluorescence confocal microscope image of the emulsion obtained before the reaction in Example 2. Figure 3 It can be seen that a stable O / W emulsion with a size of 80-110 μm is formed by homogenization or shaking for 1 min. The immobilized enzyme stabilizes the emulsion and acts as both an emulsifier and a catalyst for interfacial catalytic reactions.

[0028] Figure 4 This is a diagram showing the transesterification reaction of soybean oil and vitamin A catalyzed by different enzyme contents in Example 2.

[0029] Figure 5 This is a diagram showing the enzyme-catalyzed transesterification reactions of sunflower seed oil and chlorogenic acid at different molar ratios in Example 3.

[0030] Figure 6 This diagram illustrates the repeated use of the immobilized enzyme-catalyzed algal oil and tea polyphenol exchange reaction in Example 4.

[0031] Figure 7 This is a stability diagram of homogeneous storage under high pressure after the reaction in Example 2. Figure 7 It can be seen that after being processed by a high-pressure homogenizer, semi-finished dairy products are transformed into finished dairy products with good stability. Detailed Implementation

[0032] To better understand the present invention, the following specific embodiments further illustrate the content of the present invention, but the present invention is not limited to the following embodiments.

[0033] The specific preparation process of SiO2 microspheres in this invention is as follows: CTAB sample and solid Na2SiO3·9H2O are added to pure water, and the solution is stirred at room temperature until it becomes clear. Then, ethyl acetate is rapidly added to the mixed solution and stirred. After being left at room temperature for a period of time, it is aged for a period of time. Then, the solid product obtained from aging is filtered and dried at room temperature to obtain hollow mesoporous SiO2 microspheres (HMSS). Finally, the dried HMSS is calcined in a high-temperature tube furnace for a period of time, then dried and stored for further modification.

[0034] Further, the specific preparation process of silane-modified mesoporous silica spheres is as follows: the above-mentioned HMSS is modified with a silane coupling agent, wherein the silane coupling agent can be one or more of methyltrichlorosilane (MTCS), ethyltrichlorosilane, butyltrichlorosilane, octyltrichlorosilane, and 3-aminopropyltriethoxysilane (APTES). When 3-aminopropyltriethoxysilane (APTES) is used as the silane coupling agent, the contact angle is approximately 45°; when methyltrichlorosilane (MTCS), ethyltrichlorosilane, butyltrichlorosilane, or octyltrichlorosilane is used as the silane coupling agent, the contact angle is approximately 110°, as shown below. Figure 1 As shown in the left and right images.

[0035] The following examples illustrate the preparation method of silane-modified mesoporous silica spheres: 39.0 g of CTAB sample and 46.0 g of solid Na₂SiO₃·9H₂O were added to 700 mL of pure water, and the solution was vigorously stirred at 30 °C until it became clear. Subsequently, 75 mL of ethyl acetate was rapidly added to the mixture, and the mixture was stirred for 30 s. After standing at 30 °C for 5 h, the mixture was aged at 90 °C for 48 h. The solid product was then filtered and dried at room temperature to obtain hollow mesoporous SiO₂ microspheres (HMSS). Finally, the dried HMSS was calcined in a coffee oven at 550 °C for 5 h, dried, and stored for further use. Next, 0.5 g of HMSS sample was added to 10 mL of toluene, followed by 0.5 mmol of 3-aminopropyltriethoxysilane (APTES). The mixture was stirred at room temperature for 3 h, washed several times with ethanol, and dried in a vacuum oven (60 °C) to obtain silane coupling agent-modified hollow mesoporous SiO₂ microspheres.

[0036] The hollow mesoporous SiO2 microspheres modified with the above-mentioned silane coupling agent have a size between 3-5 μm and possess mesoporous and cavity structures. Figure 2 It can be seen that the pore size of the hollow mesoporous SiO2 microspheres remains unchanged before and after modification, with a size of 10-20 nm.

[0037] In the following examples, the specific process for preparing immobilized lipase by adsorption method is as follows: 3g of free Candida pleuri lipase (AYS) was dissolved in 50mL of phosphate buffer solution (50mM) with pH 7.0, and amino-modified mesoporous silica spheres and enzyme solution were mixed at a solid-liquid ratio of 10mg / mL. The mixture was incubated on a shaker at 30°C for 40min and then centrifuged. The precipitate was then freeze-dried to obtain immobilized lipase.

[0038] Example 1

[0039] A method and product for preparing functional ester-rich dairy products using an enzymatic method, specifically including the following steps: Take 1g of vitamin C, mix it evenly in a reaction flask at a vitamin C: flaxseed oil molar ratio of 1:14, heat and stir at 50℃ for 30min to dissolve, add 1.0g of the above immobilized lipase (with free enzyme as a control) and 100mL of skim milk, shake for 1min to form a micron-sized emulsion, then perform a transesterification reaction with magnetic stirring for 2h, centrifuge to remove the immobilized enzyme, and obtain a semi-finished dairy product; the semi-finished dairy product is homogenized and cycled 10 times under high pressure at 400pa to obtain a functional ester-rich dairy product with good stability.

[0040] The results showed that when the amount of immobilized lipase added was 7.5 mg / mL, the conversion rate of vitamin C esters was 97%, the content of diglycerides was 0.2%, and the dairy products were rich in functional esters at 1.5 g / 100 mL. The functional esters accounted for 40% of the mass percentage of fat in the dairy products and contained 56% of beneficial fatty acids, including α-linolenic acid, DHA, and EPA.

[0041] Table 1 shows the mass content of functional esters in dairy products prepared with different amounts of vitamin C in skim milk (1.0, 0.73, 0.60, 0.48 g / 100 mL). Therefore, under the preparation conditions of Example 1, the optimal ratio of vitamin C to skim milk is 1.0 g / 100 mL. Table 1 also shows the mass content of functional esters in dairy products prepared with different amounts of hydroxyl donors.

[0042] Table 1

[0043]

[0044] Example 2

[0045] A method and product for preparing functional ester-rich dairy products using an enzymatic method, specifically including the following steps: Take 0.8g of vitamin A, mix it evenly in a reaction flask at a vitamin A:soybean oil molar ratio of 1:12, heat and stir at 55℃ for 30min to dissolve, add the above-mentioned immobilized lipases at different concentrations (5, 7.5, and 10mg / mL, with free enzyme as a control) and 100mL of skim milk, homogenize with a hand-held homogenizer for 1min to form a micron-sized emulsion, perform a magnetic stirring transesterification reaction for 2h, centrifuge to remove the immobilized enzyme, and obtain a semi-finished dairy product; circulate the semi-finished dairy product under high pressure homogenization at 500pa 15 times to obtain a dairy product with good stability.

[0046] The results showed that when the amount of immobilized lipase added was 7.5 mg / mL, the conversion rate of vitamin A ester was over 95%, the content of oleic acid ester was 0.5%, and the dairy products were rich in functional esters at 1.7 g / 100 mL. The functional esters accounted for 45% of the mass percentage of oil in the dairy products and contained 57% of beneficial fatty acids, including linolenic acid, linoleic acid, and oleic acid.

[0047] Depend on Figure 4The study investigated the effect of different enzyme concentrations on conversion rate. With the same substrate content, the conversion rate increased with increasing immobilized enzyme concentration, and the conversion rate of the immobilized enzyme was consistently higher than that of the free enzyme. These results indicate that lipase immobilization helps improve lipase activity and stability; another factor may be the increased interfacial area of ​​the stabilized emulsion due to the immobilized enzyme, which increases the mass transfer rate and facilitates interfacial catalytic reactions. Furthermore, the conversion rate at an enzyme concentration of 7.5 mg / mL was not significantly different from that at 10.0 mg / mL. Therefore, 7.5 mg / mL can be selected for future studies.

[0048] Example 3

[0049] A method and product for preparing functional ester-rich dairy products using an enzymatic process, specifically comprising the following steps: 0.6 g of chlorogenic acid is mixed evenly in a reaction flask at a molar ratio of chlorogenic acid to sunflower seed oil of 1:4 to 1:14. The mixture is heated and stirred at 60°C for 30 min to dissolve. 0.5 g of the immobilized lipase and 100 mL of skim milk are added, and the mixture is homogenized for 1 min using a hand-held homogenizer to form a micron-sized emulsion. Then, a magnetically stirred transesterification reaction is performed for 2 h. The immobilized enzyme is removed by centrifugation to obtain a semi-finished dairy product. This semi-finished dairy product can be homogenized under high pressure at 600 Pa for 20 cycles to obtain a dairy product with good stability.

[0050] Table 2 shows the mass content of functional esters in dairy products prepared with different molar ratios of chlorogenic acid and sunflower seed oil (1:4, 1:8, 1:12, and 1:14, respectively). Figure 5 It was found that the conversion rate increased with increasing molar ratio of chlorogenic acid to sunflower seed oil in the range of 1:4 to 1:14, but the increase slowed down after the molar ratio reached 1:12. These results may be because excess sunflower seed oil is beneficial to the forward reaction. Although a relatively high conversion rate was ensured, excess sunflower seed oil increased the cost of the reaction. Therefore, under the preparation conditions of Example 3, the optimal ratio of chlorogenic acid to sunflower seed oil was 1:12. The conversion rate of chlorogenic esters was determined to be over 85%, the oleic acid diester content was 0.7%, and the dairy product was rich in functional esters at 1.5 g / 100 mL. The functional lipids accounted for 35% of the oil mass in the dairy product, and contained 53% beneficial fatty acids, including one or more of linoleic acid and oleic acid.

[0051] Table 2

[0052]

[0053] Example 4

[0054] A method and product for preparing functional ester-rich dairy products using an enzymatic method, specifically comprising the following steps: 0.52g of tea polyphenols are mixed evenly in a reaction flask at a tea polyphenol:algal oil molar ratio of 1:4. The mixture is heated and stirred at 65°C for 30 minutes to dissolve. 0.25g of the immobilized lipase and 100mL of skim milk are added. The mixture is homogenized for 1 minute using a hand-held homogenizer to form a micron-sized emulsion. After magnetic stirring and esterification for 2 hours, the immobilized enzyme is removed by centrifugation to obtain the semi-finished dairy product. Subsequent high-pressure homogenization is performed as in Example 2.

[0055] Tests showed that the conversion rate of tea polyphenol esters was over 80%, and the dairy products were rich in functional esters (1.0g / 100mL). The functional lipids accounted for 25% of the mass of oil in the dairy products and contained 60% of beneficial fatty acids, including one or more of DHA, EPA, and ARA.

[0056] Depend on Figure 6 It can be seen that, under optimal conditions, the relative conversion rate of tea polyphenol esters in the sixth step still remained above 70%, indicating that the immobilized lipase has good reusability and stability.

[0057] Example 5

[0058] A method and product for preparing functional ester-rich dairy products using an enzymatic process, specifically comprising the following steps: 0.73g of rutin and 100mL of whole milk are mixed in a reaction flask, with a molar ratio of rutin to fat in the whole milk of 1:12. The mixture is heated and stirred at 45°C for 30 minutes. 0.75g of the immobilized lipase is added, and the mixture is homogenized for 1 minute using a hand-held homogenizer to form a micron-sized emulsion. Then, a magnetically stirred transesterification reaction is performed for 2 hours. After centrifugation to remove the immobilized enzyme, a semi-finished dairy product is obtained. Subsequent high-pressure homogenization is performed as in Example 2.

[0059] The conversion rate of rutin ester was found to be over 78%, the content of oleic acid diester was 0.9%, and the dairy products were rich in functional esters (0.9 g / 100 mL). The functional lipids accounted for 20% of the mass percentage of oil in the dairy products and contained 53% of beneficial fatty acids, including linolenic acid, conjugated linoleic acid, linoleic acid, and oleic acid.

[0060] Example 6

[0061] The process is basically the same as Example 2, except that the oil added in step (1) is one of the following: perilla oil, hemp seed oil, evening primrose oil, peony seed oil, sunflower seed oil, soybean oil, conjugated linoleic acid glyceride, DHA algal oil, fish oil, garlic fruit oil, and Sapindus mukorossi oil.

[0062] Table 3 shows the mass content of functional esters in dairy products prepared from different triglycerides in Example 6.

[0063]

[0064] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for the enzymatic preparation of a functional lipid-enriched dairy product, characterized in that It comprises the following steps: (1) adding free enzyme into phosphate buffer solution to configure enzyme solution; then mixing enzyme solution with mixed group modified SiO2 carrier to prepare immobilized lipase after drying; wherein the SiO2 carrier is micron-sized hollow mesoporous SiO2 microspheres modified by silane coupling agent, the size is between 3-5 μm, the mesoporous pore size distribution is between 10-20 nm, and the water contact angle is 45°-110°; (2) The triglyceride and active polyhydroxy compound are mixed and dissolved at 45-65℃, the immobilized lipase obtained in step (1) and skimmed milk are added, a micron-sized emulsion is formed by homogenization or stirring, and then ester exchange or esterification is carried out in a constant-temperature water bath at 45-65℃, the reaction time is 10-120 min, the emulsion particle size is 80-110 μm, and the contact area is 690-950 cm 2 / mL; after the reaction is completed, the immobilized lipase is separated and reused, the obtained solution is a semi-product of a functional ester-rich dairy product, and the functional ester-rich dairy product is obtained by high-pressure homogenization, and the content of the functional fat in the dairy product reaches 0.5 g-3.0 g / 100 mL.

2. A method for the enzymatic preparation of a functional lipid enriched dairy product, characterized in that It comprises the following steps: (1) adding free enzyme into phosphate buffer solution to configure enzyme solution; then mixing enzyme solution with SiO2 carrier to prepare immobilized lipase after drying; wherein the SiO2 carrier is micron-sized hollow mesoporous SiO2 microspheres modified by silane coupling agent, the size is between 3-5 μm, the mesoporous pore size distribution is between 10-20 nm, and the water contact angle is 45°-110°; (2) The active polyhydroxyl compound and the full-fat dairy product are mixed uniformly in a water bath at 45-65°C, the immobilized lipase obtained in step (1) is added, a micron-sized emulsion is formed by homogenization or stirring, and then an esterification or transesterification reaction is carried out in a constant-temperature water bath at 45-65°C, the reaction time is 10-120 min, the emulsion particle size is between 80-110 μm, and the contact area is 690-950 cm 2 / mL; after the reaction is completed, the immobilized lipase is separated and reused, the obtained solution is a semi-product of a functional ester-enriched dairy product, and the functional ester-enriched dairy product is obtained by high-pressure homogenization, and the content of the functional fat in the dairy product reaches 0.5 g-3.0 g / 100 mL; The full-fat dairy product is one or a mixture of several of full-fat milk, flax milk, peanut milk, walnut milk, almond milk, soy milk, oat milk, etc.

3. A process for the enzymatic preparation of a functional lipid-enriched dairy product according to claim 1 or 2, characterized in that The active polyhydroxyl compound is one or a mixture of several of vitamin A, vitamin A ethyl ester, vitamin C, vitamin C ethyl ester, tea polyphenol, tea polyphenol ethyl ester, rutin, resveratrol, resveratrol ethyl ester, chlorogenic acid, chlorogenic acid ethyl ester in any proportion.

4. A process for the enzymatic preparation of a functional lipid enriched dairy product according to claim 1, characterized in that In step (2), the molar ratio of active polyhydroxyl compound to triglyceride is 1:4-1:14; the triglyceride is one or a mixture of several of flaxseed oil, perilla oil, hemp oil, evening primrose oil, peony seed oil, sunflower seed oil, soybean oil, sunflower seed oil, conjugated linoleic acid glyceride, DHA algal oil, fish oil, garcinia indica oil, xanthoceras sorbifolia bunge oil in any proportion.

5. A process for the enzymatic preparation of a functional lipid enriched dairy product according to claim 1 or 2, characterized in that In step (2), the content of active polyhydroxyl compound in the dairy product is 0.5-10 g / mL, and the addition amount of immobilized lipase in the dairy product is 1-20 mg / mL.

6. A process for the enzymatic preparation of a functional lipid enriched dairy product according to claim 1 or 2, characterized in that In step (1), the free enzyme is one or more of Candida rugosa lipase, Candida antarctica lipase, Candida rugosa lipase, NS40086 lipase, Thermomyces lanuginosus, Candida lipolytica lipase; the pH of the enzyme solution is 6.0-9.0, and the concentration is 30-200 mg / mL; the ratio of carrier mass to enzyme solution volume is 1:100-5:100 (m / v, g / mL); the immobilization time is 10-60 min, and the temperature is 20-40℃; the pH of the phosphate buffer solution is 6.0-9.

0.

7. A process for the enzymatic preparation of a functional lipid enriched dairy product according to claim 1 or 2, characterized in that In step (2), the high-pressure homogenization is treated by high-pressure homogenizer for 10-20 cycles at a pressure of 400-600 Pa.

8. The functional lipid-enriched dairy product produced by the method of claim 1 or 2, characterized in that, The diacylglycerol content is 0.1%-3%, the generated functional lipid accounts for 0.5 g-3.0 g / 100 mL of the content of the dairy product; the mass percentage of functional lipid in the oil in the dairy product is 20%-60%; the content of beneficial fatty acids in the functional ester is more than 53%, and the beneficial fatty acids include one or more of linolenic acid, nervonic acid, oleic acid, linoleic acid, DHA, EPA, and ARA.

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