Method for increasing content of polyphenol in diglyceride oil

Abstract

The invention discloses a method for increasing the content of polyphenols in diglyceride oil, particularly relates to the technical field of materials, and relates to a method for increasing the content of polyphenols in diglyceride oil. The diglyceride oil is prepared from activated polyphenol powder, vegetable oil, lipase and deionized water; the diglyceride oil is prepared from the following raw material components in parts by weight: 80 to 150 parts of activated polyphenol powder, 10000 parts of vegetable oil, 3 to 8 parts of lipase and 400 to 700 parts of deionized water. According to the invention, a synergistic effect mechanism of a compound emulsifier and enzyme catalysis is established, a molecular film is formed on an oil-water interface by utilizing a phospholipid and sucrose ester compound system, and meanwhile, molecular combination of polyphenol and glyceride is catalyzed by virtue of lipase to form a stable polyphenol-grease complex, so that migration and precipitation of polyphenol in a processing process are effectively prevented, and the stability of the polyphenol-grease complex is improved. Therefore, the polyphenol retention rate is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and more specifically, to a method for increasing the polyphenol content of diglyceride oil. Background Technology

[0002] Diglycerides are a naturally occurring oil component; they are healthy oils with functions such as lowering blood pressure, blood sugar, cholesterol, and cholesterol levels, and promoting weight control, making them an effective carrier for novel functional food ingredients. Polyphenols are a class of natural antioxidants widely found in plants, possessing various physiological activities such as anti-inflammatory, antioxidant, and cardiovascular disease prevention, which can enhance the antioxidant capacity of vegetable oils and extend their shelf life. Therefore, developing a new method that can synthesize diglycerides while significantly increasing and retaining polyphenol content is of great significance for improving the nutritional value and market competitiveness of diglyceride oils.

[0003] The preparation of diglyceride oil in related technologies mainly relies on glycerol hydrolysis, which includes triglyceride raw materials, glycerol, and catalysts. Among them, triglyceride raw materials serve as the basic substrate for the reaction, providing the glycerol skeleton and fatty acids, and are mostly economic crop oils such as soybean oil and rapeseed oil. Glycerol, as a reactant, undergoes alcoholysis with triglycerides. Alkaline catalysts, such as sodium methoxide and sodium hydroxide, are usually used to accelerate the reaction. Diglycerides are enriched by changing the molecular structure of the oil.

[0004] However, in practical use, it still has some drawbacks, such as poor nutrient retention. In order to reduce costs, traditional processes often use refined vegetable oils with very low polyphenol content as raw materials, which limits the potential polyphenol content in the product from the source. Polyphenol loss is serious. The deodorization and decolorization refining steps required by traditional methods require high-temperature treatment, which leads to a large loss of residual polyphenols due to volatilization, oxidation or thermal decomposition. The enrichment degree is low. Traditional methods do not have the ability to activate bound polyphenols in raw materials. Bound polyphenols with low bioavailability in the form of glycosides cannot be effectively converted and are eventually removed during the refining process, resulting in a low enrichment degree. Summary of the Invention

[0005] To improve the above-mentioned problems and reduce the issues of poor nutrient retention, severe polyphenol loss, and low enrichment of diglyceride oil in related technologies, this invention provides a method for increasing the polyphenol content of diglyceride oil to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A method for increasing the polyphenol content of diglyceride oil includes the following steps: S1. The plant polyphenol extract is processed by a pulverizer to obtain activated polyphenol powder with a particle size of less than 20μm; S2. The activated polyphenol powder obtained in S1, vegetable oil, lipase and deionized water are put into a reaction vessel with a constant temperature jacket. The reaction is carried out at a constant temperature of 250-350 rpm and 78-82℃ under nitrogen protection for 3-5 hours to obtain the enzyme-catalyzed reactant. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at 6000 rpm. The upper oil phase is collected and then filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane for two-stage filtration to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

[0007] Preferably, the raw materials for preparing the diglyceride oil and their weight proportions are as follows: 80-150 parts activated polyphenol powder, 10,000 parts vegetable oil, 3-8 parts lipase, and 400-700 parts deionized water.

[0008] Preferably, the plant polyphenol extract is a tea polyphenol extract with a polyphenol content of ≥95%.

[0009] Preferably, the vegetable oil is a mixture of diglycerides, phospholipids and sucrose esters as a composite emulsifier, and soybean oil in a weight ratio of 85:2:15.

[0010] Preferably, the phospholipid and sucrose ester composite emulsifier is composed of phospholipid and sucrose ester in a mass ratio of 3:1.

[0011] Preferably, the lipase is immobilized lipase Novozym 435.

[0012] 1. This invention constructs a synergistic system of enzyme catalysis and mass transfer optimization, and utilizes lipase to activate the binding activity of polyphenols and oil molecules at the oil-water interface, enabling exogenous polyphenols to be efficiently embedded into the diglyceride molecular network, thereby significantly improving the solubility and stability of polyphenols in the oil phase. 2. This invention establishes a synergistic mechanism between composite emulsifiers and enzyme catalysis, utilizing a phospholipid and sucrose ester complex system to form a molecular film at the oil-water interface. Simultaneously, it leverages lipase to catalyze the molecular binding of polyphenols and glycerides, forming a stable polyphenol-oil complex. This effectively prevents the migration and precipitation of polyphenols during processing, thereby significantly improving the polyphenol retention rate. 3. This invention achieves simultaneous optimization of polyphenol morphology and enhancement of function by using an enzyme system to efficiently convert bound polyphenols into free polyphenols with higher bioactivity while catalyzing the synthesis of diglycerides, thus maintaining the nutritional quality of the product. Detailed Implementation

[0013] The present invention will be further described in detail below with reference to the embodiments of the present invention. Unless otherwise specified below, the raw materials used in the various examples and embodiments of the present invention are all commercially available common materials. Preparation Examples 1-5 A diglyceride oil, the components and their corresponding proportions of which are shown in the table below, is prepared using the following method: S1. The plant polyphenol extract is processed by a pulverizer to obtain activated polyphenol powder with a particle size of less than 20μm; The plant polyphenol extract is a tea polyphenol extract with a polyphenol content of ≥95%; S2. The activated polyphenol powder, vegetable oil, lipase and deionized water obtained in S1 are put into a reaction vessel with a constant temperature jacket and reacted at 300 rpm, 80°C and nitrogen protection for 4 hours to obtain the enzyme-catalyzed reactant. The vegetable oil is composed of diglycerides, phospholipids and sucrose esters as a compound emulsifier, and soybean oil in a weight ratio of 85:2:15. The phospholipid and sucrose ester composite emulsifier is composed of phospholipids and sucrose esters in a mass ratio of 3:1. The lipase used was the immobilized lipase Novozym 435. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at 6000 rpm. The upper oil phase is collected and then filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane for two-stage filtration to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

[0014] Table: Components and their mass ratios (g) of the raw materials used in Preparation Examples 1-5 Preparation Example 6 A diglyceride oil, differing from Preparation Example 1 in that its preparation method is as follows: S1. The plant polyphenol extract is processed by a pulverizer to obtain activated polyphenol powder with a particle size of less than 20μm; S2. The activated polyphenol powder, vegetable oil, lipase and deionized water obtained in S1 are put into a reaction vessel with a constant temperature jacket and reacted at 250 rpm, 80°C and nitrogen protection for 4 hours to obtain the enzyme-catalyzed reactant. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at 6000 rpm. The upper oil phase is collected and then filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane for two-stage filtration to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

[0015] Preparation Example 7 A diglyceride oil, differing from Preparation Example 1 in that its preparation method is as follows: S1. The plant polyphenol extract is processed by a pulverizer to obtain activated polyphenol powder with a particle size of less than 20μm; S2. The activated polyphenol powder, vegetable oil, lipase and deionized water obtained in S1 are put into a reaction vessel with a constant temperature jacket and reacted at 350 rpm, 80°C and nitrogen protection for 4 hours to obtain the enzyme-catalyzed reactant. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at 6000 rpm. The upper oil phase is collected and then filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane for two-stage filtration to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

[0016] Preparation Example 8 A diglyceride oil, differing from Preparation Example 1 in that its preparation method is as follows: S1. The plant polyphenol extract is processed by a pulverizer to obtain activated polyphenol powder with a particle size of less than 20μm; S2. The activated polyphenol powder, vegetable oil, lipase and deionized water obtained in S1 are put into a reaction vessel with a constant temperature jacket and reacted at a constant temperature of 78°C for 4 hours under nitrogen protection to obtain the enzyme-catalyzed reactant. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at 6000 rpm. The upper oil phase is collected and then filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane for two-stage filtration to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

[0017] Preparation Example 9 A diglyceride oil, differing from Preparation Example 1 in that its preparation method is as follows: S1. The plant polyphenol extract is processed by a pulverizer to obtain activated polyphenol powder with a particle size of less than 20μm; S2. The activated polyphenol powder, vegetable oil, lipase and deionized water obtained in S1 are put into a reaction vessel with a constant temperature jacket and reacted at a constant temperature of 82°C for 4 hours under nitrogen protection to obtain the enzyme-catalyzed reactant. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at 6000 rpm. The upper oil phase is collected and then filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane for two-stage filtration to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

[0018] Preparation Example 10 A diglyceride oil, differing from Preparation Example 1 in that its preparation method is as follows: S1. The plant polyphenol extract is processed by a pulverizer to obtain activated polyphenol powder with a particle size of less than 20μm; S2. The activated polyphenol powder, vegetable oil, lipase and deionized water obtained in S1 are put into a reaction vessel with a constant temperature jacket and reacted at 250 rpm, 80°C and nitrogen protection for 3 hours to obtain the enzyme-catalyzed reactant. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at 6000 rpm. The upper oil phase is collected and then filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane for two-stage filtration to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

[0019] Preparation Example 11 A diglyceride oil, differing from Preparation Example 1 in that its preparation method is as follows: S1. The plant polyphenol extract is processed by a pulverizer to obtain activated polyphenol powder with a particle size of less than 20μm; S2. The activated polyphenol powder, vegetable oil, lipase and deionized water obtained in S1 are put into a reaction vessel with a constant temperature jacket and reacted at a constant temperature of 250 rpm and 80°C for 5 hours under nitrogen protection to obtain the enzyme-catalyzed reactant. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at 6000 rpm. The upper oil phase is collected and then filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane for two-stage filtration to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

[0020] Performance testing The diglyceride oils prepared in each example were selected for testing. The test subjects were 110 samples of diglyceride oil, 10 samples per group. The content of their core functional components, oxidative stability, and polyphenol enrichment efficiency were measured. The specific testing steps are as follows: Content of core functional ingredients: First, samples of the diglyceride oil prepared in the examples were taken and qualitatively and quantitatively analyzed by gas chromatography according to national standards. The mass percentage of diglycerides in the total glycerides was calculated to characterize the diglyceride content. The Folin-phenol method was used, with gallic acid as a standard, and the absorbance was measured at 765 nm. A standard curve was plotted, and the total polyphenol content was calculated as gallic acid equivalents per kilogram of oil. Diglyceride content ≥40% (considered high diglyceride content); Diglyceride content <40% (considered low diglyceride content); Polyphenol content ≥200mg GAEs / kg (considered as high polyphenol content); Polyphenol content <200mg GAEs / kg (considered low polyphenol content).

[0021] Oxidative stability: First, samples of the diglyceride oil prepared in the examples were taken. Following national standards, the oil samples were continuously purged with air at 110°C using a Laplace apparatus, and the induction time was measured for 15 hours. Before and after the accelerated oxidation test, the total polyphenol content of the oil samples was measured, and the retention rate was calculated to characterize the oxidative stability of the diglyceride oil. The test results and evaluation criteria are as follows: Polyphenol retention rate >70% (considered good oxidative stability); Polyphenol retention rate <70% (considered as poor oxidative stability).

[0022] Polyphenol enrichment efficiency: First, samples of the diglyceride oil obtained in the examples were taken to determine the polyphenol content of the finished product and calculate the total amount of polyphenols fed to the sample to obtain the enrichment efficiency, thereby characterizing the enrichment efficiency of the diglyceride oil; the test results and evaluation criteria are as follows: Enrichment efficiency ≥70% (considered high polyphenol enrichment efficiency); Enrichment efficiency <70% (considered as low polyphenol enrichment efficiency).

[0023] It should be specifically noted that the diglyceride oil obtained above is the diglyceride oil produced in accordance with normal production methods. Any defective diglyceride oil produced should be discarded and its data disregarded.

[0024] Examples 1-5 The corresponding relationship of the preparation methods of a diglyceride oil is shown in the table below.

[0025] Table: Comparison of Diglyceride Oil Usage in Examples 1-5 Extract the diglyceride oil from Examples 1-5 above, and test its core functional component content, oxidative stability, and polyphenol enrichment efficiency according to the above measurement steps and standards. The average value of the test results is recorded in the table below.

[0026] Table: Performance test results of diglyceride content, polyphenol content, polyphenol retention rate, and enrichment efficiency in Examples 1-5 As can be seen from the table above, the diglyceride oil preparation processes in Examples 1-5 all effectively improved the production efficiency of diglyceride oil. Tea polyphenol extract, as the core functional factor, directly enhanced the antioxidant efficacy of the oil system due to its high concentration of phenolic hydroxyl groups. Simultaneously, it participated in constructing the functional framework of the final product as an enriched target active ingredient. The diglyceride base in the specially formulated plant oil system constituted the main functional skeleton of the product. The phospholipid and sucrose ester compound emulsifier formed a stable film at the oil-water interface through molecular self-assembly, significantly improving the dispersibility and compatibility of polyphenols in the oil phase. The soybean oil carrier effectively regulated the rheological properties of the system, collectively forming a polyphenol-oil composite system. The formation of the enzyme creates an ideal thermodynamic environment; the immobilized lipase utilizes its unique interfacial activation characteristics to mediate the specific binding of polyphenol molecules and oil molecules while catalyzing the reconstruction of diglycerides, achieving in-situ anchoring and stabilization of polyphenols in the oil phase; deionized water, as the reaction medium, not only maintains the enzyme's active conformation but also drives the directional migration of polyphenols from the aqueous phase to the oil phase by constructing a dynamic mass transfer system, ultimately achieving efficient separation of unreacted components and the stabilized complex system during the molecular distillation stage. This multi-component synergistic mechanism fundamentally improves the retention efficiency and enrichment of polyphenols while ensuring the structural integrity of the core functional components of diglycerides; thus achieving the goal of improving the production efficiency of diglyceride oil. Its diglyceride content is 48.5-53.9%, which is considered high; its polyphenol content is 285-498 mg GAEs / kg, which is considered high; its polyphenol retention rate is 82.7-89.5%, which is considered good oxidative stability; and its enrichment efficiency is 76.8-85.7%, which is considered high polyphenol enrichment efficiency. It is evident that, given a fixed amount of raw materials, the production efficiency of diglyceride oil can be increased by adjusting the proportions of the raw materials. Based on the data in the table above, it is clear that the diglyceride oil prepared using 100 parts activated polyphenol powder, 10,000 parts vegetable oil, 8 parts lipase, and 700 parts deionized water exhibits the highest diglyceride content, polyphenol retention rate, and enrichment efficiency. This is because, at this ratio, the sufficiently immobilized lipase fully exerts its catalytic efficiency within the ideal reaction microenvironment constructed by an appropriate amount of deionized water, significantly promoting... The synthesis and transformation of diglycerides is facilitated by the molecular interface, which guides the close binding of polyphenols with the lipid system. The appropriate proportion of deionized water not only provides the necessary medium for the enzyme-catalyzed reaction, but also promotes the efficient and directional migration of polyphenol molecules from the aqueous phase to the oil phase by optimizing mass transfer kinetics. At the same time, the sufficient amount of enzyme ensures that polyphenols can be captured in time and stably anchored in the lipid molecular network during the migration process. This synergistic system effectively balances the two key processes of diglyceride synthesis and polyphenol enrichment, so that polyphenols can be retained to the maximum extent in the subsequent purification stage, as obtained from Examples 1-5.

[0027] It is evident that, given a fixed amount of raw materials, the production efficiency of diglyceride oil can be increased by adjusting the proportions of these materials. Based on the data in the table above, it is clear that the diglyceride oil prepared using 150 parts activated polyphenol powder, 10,000 parts vegetable oil, 7 parts lipase, and 600 parts deionized water exhibits the highest polyphenol content. This is because this ratio significantly increases the proportion of activated polyphenol powder, directly increasing the number of polyphenol molecules in the reaction system and providing a sufficient raw material basis for the full combination of polyphenols and oils. Meanwhile, this scheme increases the amount of immobilized lipase, and the enhanced enzyme concentration effectively catalyzes the esterification and intercalation reactions of more polyphenol molecules with diglyceride base oil. The increased water content optimizes the mass transfer environment and promotes the distribution and migration of polyphenols between the oil and water phases. This synergistic design of high polyphenol feed and enhanced enzyme catalysis ensures that despite some substrate competition, the system can still drive sufficient polyphenols to successfully embed into the oil network and be stably retained in the subsequent purification process, thereby achieving the highest polyphenol enrichment concentration in the final product, as obtained from Examples 1-5.

[0028] However, considering both cost and process, the diglyceride oil prepared by Example 1, which consists of 100 parts activated polyphenol powder, 10,000 parts vegetable oil, 5 parts lipase, and 500 parts deionized water, shows the best overall performance in terms of balanced indicators and cost-effectiveness.

[0029] Examples 6-11 The corresponding relationship of the preparation methods of a diglyceride oil is shown in the table below.

[0030] Table: Comparison of Diglyceride Oil Usage in Examples 6-11 Extract the diglyceride oil from Examples 6-11 above, and test its core functional component content, oxidative stability, and polyphenol enrichment efficiency according to the above measurement steps and standards. The average value of the test results is recorded in the table below.

[0031] Table: Performance test results of diglyceride content, polyphenol content, polyphenol retention rate, and enrichment efficiency in Examples 1, 6-11 As can be seen from the table above, the diglyceride oil preparation processes in Examples 1 and 6-11 all effectively improved the production efficiency of diglyceride oil. Tea polyphenol extract, as a core functional factor, directly enhanced the antioxidant efficacy of the oil system due to its high concentration of phenolic hydroxyl structures. Simultaneously, it participated in constructing the functional framework of the final product as an enriched target active ingredient. The diglyceride base in the specially formulated plant oil system constituted the main functional skeleton of the product. The phospholipid and sucrose ester compound emulsifier formed a stable film at the oil-water interface through molecular self-assembly, significantly improving the dispersibility and compatibility of polyphenols in the oil phase. The soybean oil carrier effectively regulated the rheological properties of the system, collectively forming a polyphenol-oil complex. The formation of the system creates an ideal thermodynamic environment; the immobilized lipase utilizes its unique interfacial activation characteristics to mediate the specific binding of polyphenol molecules and oil molecules while catalyzing the reconstruction of diglycerides, achieving in-situ anchoring and stabilization of polyphenols in the oil phase; deionized water, as the reaction medium, not only maintains the enzyme's active conformation but also drives the directional migration of polyphenols from the aqueous phase to the oil phase by constructing a dynamic mass transfer system, ultimately achieving efficient separation of unreacted components and the stabilized complex system during the molecular distillation stage. This multi-component synergistic mechanism fundamentally improves the retention efficiency and enrichment of polyphenols while ensuring the structural integrity of the core functional components of diglycerides; thus achieving the goal of improving the production efficiency of diglyceride oil. Its diglyceride content is 51.7-52.7%, which is considered high; its polyphenol content is 337-372 mg GAEs / kg, which is considered high; its polyphenol retention rate is 84.9-87.4%, which is considered good oxidative stability; and its enrichment efficiency is 81.2-83.2%, which is considered high polyphenol enrichment efficiency. It is evident that, given a fixed amount of raw materials, the production efficiency of diglyceride oil can be increased by adjusting the preparation conditions. Based on the data in the table above, it is clear that the diglyceride oil prepared under the following conditions—a constant temperature reaction at 80℃ and a rotation speed of 300 rpm for 4 hours during the enzyme-catalyzed reaction—exhibits the highest diglyceride content, polyphenol content, polyphenol retention rate, and enrichment efficiency. This is because the reaction temperature at this point maximizes the activation of the immobilized lipase's catalytic activity, promoting efficient diglyceride synthesis and the full formation of the polyphenol-lipid complex, while also effectively... This avoids the risk of polyphenol oxidative degradation caused by high temperature; at the same time, this stirring speed creates an ideal hydrodynamic environment, which can ensure that the polyphenol powder and enzyme preparation are uniformly dispersed and fully contacted in the oil and water phases to accelerate the interfacial catalytic reaction, while avoiding the mechanical damage of excessive shear force to the enzyme structure and activity and the formed complex system; and this isothermal reaction time provides a complete dynamic equilibrium cycle for the entire system, which can ensure the full progress of the diglyceride synthesis reaction and the polyphenol anchoring process, while preventing the accumulation of side reactions and component degradation caused by excessive time, as obtained from Examples 1 and 6-11.

[0032] This specific embodiment is merely an explanation of the present invention and not a limitation thereof. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A method for increasing the polyphenol content of diglyceride oil, characterized in that, Includes the following steps: S1. Plant polyphenol extracts are processed by a pulverizer to obtain activated polyphenol powder; S2. The activated polyphenol powder obtained in S1, vegetable oil, lipase and deionized water are put into a reaction vessel with a constant temperature jacket. The reaction is carried out at a constant temperature of 250-350 rpm and 78-82℃ under nitrogen protection for 3-5 hours to obtain the enzyme-catalyzed reactant. S3. The enzyme-catalyzed reactants obtained in S2 are introduced into a disc centrifuge and separated into oil and water at a speed of 6000 rpm. The upper oil phase is collected and then filtered through two stages to obtain the filtered oil. S4. The filtered oil obtained in S3 is fed into a molecular distillation apparatus. The distilled heavy components are collected under the conditions of evaporation temperature of 160℃, system pressure of 0.5Pa, and feed rate of 1.5L / h to obtain diglyceride oil.

2. The method for increasing the polyphenol content of diglyceride oil according to claim 1, characterized in that: The components and weight proportions of the raw materials for preparing the diglyceride oil are as follows: 80-150 parts activated polyphenol powder, 10,000 parts vegetable oil, 3-8 parts lipase, and 400-700 parts deionized water.

3. The method for increasing the polyphenol content of diglyceride oil according to claim 1, characterized in that: The plant polyphenol extract is a tea polyphenol extract with a polyphenol content of ≥95%.

4. The method for increasing the polyphenol content of diglyceride oil according to claim 1, characterized in that: The vegetable oil is composed of diglycerides, phospholipids and sucrose esters as a composite emulsifier, and soybean oil in a weight ratio of 85:2:

15.

5. The method for increasing the polyphenol content of diglyceride oil according to claim 4, characterized in that: The phospholipid and sucrose ester composite emulsifier is composed of phospholipids and sucrose esters in a mass ratio of 3:

1.

6. The method for increasing the polyphenol content of diglyceride oil according to claim 1, characterized in that: The lipase mentioned is the immobilized lipase Novozym 435.

7. The method for increasing the polyphenol content of diglyceride oil according to claim 1, characterized in that: The plant polyphenol extract in S1 is processed by a pulverizer to a particle size of less than 20 μm.

8. The method for increasing the polyphenol content of diglyceride oil according to claim 1, characterized in that: The two-stage filtration in S3 specifically involves the upper oil phase being filtered through a 200-mesh stainless steel filter and a 0.22μm polytetrafluoroethylene microporous membrane.

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