A kind of diglyceride rich in polyunsaturated fatty acids and preparation method thereof

Abstract

The invention relates to the technical field of diglyceride preparation, and specifically discloses a diglyceride rich in polyunsaturated fatty acids and a preparation method thereof, comprising: S1, fatty acid extraction and enrichment, S2, selective synthesis of diglyceride, S3, product purification and S4, antioxidant treatment; the invention uses supercritical fluid extraction technology to efficiently enrich polyunsaturated fatty acids (PUFA) from vegetable oil or marine oil, and the PUFA content in the final product is as high as 85%-98%, especially linoleic acid, α-linolenic acid, DHA and EPA have a scientific and reasonable ratio, which helps to: regulate serum cholesterol and low-density lipoprotein (LDL) and reduce the risk of arteriosclerosis; polyunsaturated fatty acids are proven to have significant effects on lowering blood lipids and anti-inflammation; DHA and EPA are key nutrients for the growth and development of infants and young children.

Description

Technical Field

[0001] The invention belongs to the technical field of diglyceride preparation, and particularly relates to a diglyceride rich in polyunsaturated fatty acids and a preparation method thereof. Background Art

[0002] As people's demand for dietary health continues to increase, functional oils, especially those rich in polyunsaturated fatty acids (PUFA), have attracted much attention due to their significant effects in cardiovascular health management, lowering blood lipids, anti-inflammation and promoting infant development. However, the current existing technology still has the following major deficiencies in the preparation of PUFA-rich diglycerides:

[0003] Traditional fatty acid extraction methods, such as solvent extraction and step-by-step refining, often require the use of large amounts of organic solvents, which not only pose a safety hazard of solvent residues, but can also lead to loss or oxidation of target fatty acids, resulting in low extraction efficiency.

[0004] In addition, the lack of selective enrichment of polyunsaturated fatty acids (such as linoleic acid, α-linolenic acid, DHA and EPA) during the extraction process leads to insufficient functionality and nutritional value of the final product.

[0005] Based on the above shortcomings, there is an urgent need for a new technical solution that can achieve efficient enrichment and protection of polyunsaturated fatty acids, and at the same time prepare high-purity diglyceride oils through mild and environmentally friendly process conditions, significantly improving the functionality, safety and storage stability of the product, and having good industrialization potential.

[0006] In view of this, the inventors proposed a diglyceride rich in polyunsaturated fatty acids and a preparation method thereof to solve the above problems. Summary of the invention

[0007] The object of the present invention is to provide a diglyceride rich in polyunsaturated fatty acids and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A diglyceride rich in polyunsaturated fatty acids comprises, by weight, 100-120 parts of natural vegetable oil, 25-35 parts of glycerol, 0.02-0.05 parts of antioxidant, 3-5 parts of catalyst and 10-15 parts of extraction co-solvent.

[0010] Preferably, the natural vegetable oil is at least one of linseed oil, fish oil, linoleic acid, α-linolenic acid, DHA and EPA.

[0011] Preferably, the antioxidant is natural tocopherol or rosemary extract, which is used to improve the storage stability of oils and fats.

[0012] Preferably, the catalyst is a specific lipase, and the specific lipase includes at least one of Lipase TLIM and Novozym 435.

[0013] A method for preparing diglyceride rich in polyunsaturated fatty acids comprises the following steps:

[0014] S1. Fatty acid extraction and enrichment: Use supercritical fluid extraction technology to separate and enrich polyunsaturated fatty acids from natural vegetable oils;

[0015] S2, selective synthesis of diglyceride: esterifying the enriched polyunsaturated fatty acids with glycerol under the action of a catalyst to obtain diglyceride;

[0016] S3, product purification: purifying the diglyceride by molecular distillation technology to remove impurities and obtain high-purity diglyceride;

[0017] S4. Antioxidant treatment: adding antioxidants to the purified oil to obtain diglycerides rich in polyunsaturated fatty acids.

[0018] Preferably, in the supercritical fluid extraction technology, the extraction medium is carbon dioxide, the operating pressure is 20-40 MPa, the temperature is 35-50° C., and the co-solvent is ethanol, and the addition amount is 5%-15%.

[0019] Preferably, the reaction conditions of the esterification reaction are: the molar ratio of glycerol to polyunsaturated fatty acids is 3:1 to 6:1, the reaction temperature is 25-45° C., the reaction time is 10-24 hours, and the reaction environment is a vacuum condition of 50-100 mbar.

[0020] Preferably, the distillation temperature of the molecular distillation technology is 100-150° C., the distillation vacuum degree is 0.001-0.01 mbar, and the diglyceride content after purification is more than 90%.

[0021] Preferably, the antioxidant is natural tocopherol, and the added amount is 0.02%-0.05% of the total mass of the target product.

[0022] Preferably, in the fatty acid composition of the polyunsaturated fatty acid-rich diglyceride, the polyunsaturated fatty acid content is 85%-98%; the diglyceride content is 90%-95%, the triglyceride content is not higher than 5%, and the monoglyceride content is 2%-3%.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention uses supercritical fluid extraction technology to efficiently enrich polyunsaturated fatty acids (PUFA) from vegetable oil or marine oil. The PUFA content in the final product is as high as 85%-98%, especially the ratio of linoleic acid, α-linolenic acid, DHA and EPA is scientific and reasonable, which helps to: regulate serum cholesterol and low-density lipoprotein (LDL) and reduce the risk of arteriosclerosis; polyunsaturated fatty acids have been proven to have significant effects in lowering blood lipids and anti-inflammation; DHA and EPA are key nutrients for the growth and development of infants and young children.

[0025] (2) The present invention adopts green and sustainable technology, and no organic solvent remains during the supercritical fluid extraction process, which meets the requirements of food-grade production; the lipase-catalyzed reaction avoids the use of chemical catalysts, has mild reaction conditions, high catalytic efficiency, no by-product pollution, strong process controllability, and clear parameters in each link, which is convenient for large-scale industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The present invention is a flow chart of a method for preparing diglyceride rich in polyunsaturated fatty acids. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Embodiment 1:

[0029] See also Figure 1 A diglyceride rich in polyunsaturated fatty acids, comprising:

[0030] 100 parts of linseed oil, 25 parts of glycerol, purity above 99%, 0.05 parts of natural tocopherol, 4353 parts of Novozym and 10 parts of ethanol.

[0031] A method for preparing diglyceride rich in polyunsaturated fatty acids comprises the following steps:

[0032] 1. Add linseed oil to the supercritical fluid extraction device and set the following conditions:

[0033] CO2 pressure: 30MPa;

[0034] Temperature: 45℃;

[0035] Co-solvent: ethanol.

[0036] After 2 hours of extraction, the polyunsaturated fatty acid-containing fraction was collected and analyzed by gas chromatography (GC), confirming that the polyunsaturated fatty acid (PUFA) content was increased to 88%.

[0037] 2. Esterification Synthesis of Diacylglycerol

[0038] The extracted polyunsaturated fatty acids were mixed with glycerol at a molar ratio of 4:1 and Novozym 435 was added.

[0039] The reaction was stirred at 35°C under vacuum (50 mbar) for 24 hours.

[0040] After the reaction, the crude product is subjected to molecular distillation to remove monoglyceride and free fatty acids, thereby obtaining oil with a diglyceride content of about 92%.

[0041] 3. Antioxidant treatment

[0042] 0.03% tocopherol is added to the prepared diglyceride oil and fat, and the mixture is stirred evenly to obtain the final product of diglyceride rich in polyunsaturated fatty acids.

[0043] The fatty acid composition of diglycerides rich in polyunsaturated fatty acids includes 88% polyunsaturated fatty acids, 92% diglycerides, more than 2% triglycerides, and 2%-3% monoglycerides.

[0044] As can be seen from the above, the present invention uses supercritical fluid extraction technology to efficiently enrich polyunsaturated fatty acids (PUFA) from vegetable oil or marine oil, and the PUFA content in the final product is as high as 85%-98%, especially the ratio of linoleic acid, α-linolenic acid, DHA and EPA is scientific and reasonable, which helps to: regulate serum cholesterol and low-density lipoprotein (LDL) and reduce the risk of arteriosclerosis; polyunsaturated fatty acids have been proven to have significant effects in lowering blood lipids and anti-inflammation; DHA and EPA are key nutrients for the growth and development of infants and young children;

[0045] The present invention adopts green and sustainable technology, and no organic solvent remains in the supercritical fluid extraction process, which meets the food-grade production requirements; the lipase catalytic reaction avoids the use of chemical catalysts, has mild reaction conditions, high catalytic efficiency, no by-product pollution, strong process controllability, clear parameters in each link, and is convenient for large-scale industrial application.

[0046] Embodiment 2:

[0047] The diglyceride rich in polyunsaturated fatty acids prepared in Example 1 was tested as follows:

[0048] 1) Oil quality test

[0049] 1. Fatty acid composition analysis

[0050] Purpose of Test: To determine the fatty acid composition of the final product.

[0051] Detection method: gas chromatography (GC).

[0052] The test data is shown in Table 1 below:

[0053] Fatty acid type Linoleic acid α-linolenic acid DHA EPA other content(%) 55.6 24.3 10.1 5.7 4.3

[0054] Table 1

[0055] 2. Low temperature storage stability test

[0056] Purpose of test: To evaluate the stability of oils and fats under low temperature storage conditions.

[0057] Detection method:

[0058] Store at 10℃, 0℃, and -5℃ for 1 month respectively;

[0059] Samples were taken every 7 days to observe the appearance and crystallization phenomenon and to detect changes in fatty acid composition.

[0060] Test data:

[0061]

[0062]

[0063] Table 2

[0064] 2) Functional testing

[0065] 1. Antioxidant capacity test

[0066] Test purpose: To detect the DPPH free radical scavenging rate;

[0067] Experimental method: In vitro antioxidant capacity test: Determined by DPPH free radical scavenging rate. Test data:

[0068] Reagent concentration (mg / mL) Free radical scavenging rate (%) 0.5 50.2 1.0 75.6 2.0 89.2

[0069] Table 3

[0070] 2. Human trials

[0071] Purpose of the test: To evaluate the effect of fats and oils on improving blood lipid health.

[0072] Experimental method: 10 volunteers consumed 10g of fat daily for 4 weeks.

[0073] Test data:

[0074]

[0075]

[0076] Table 4

[0077] From the above, it can be seen that both supercritical fluid extraction and esterification reaction show high efficiency.

[0078] The final product has a reasonable fatty acid composition, with a polyunsaturated fatty acid content of up to 88%.

[0079] No crystallization or stratification occurs at low temperatures, showing excellent storage performance.

[0080] It has a significant lipid-lowering effect and strong antioxidant capacity, making it suitable for promotion as a healthy functional oil.

[0081] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0082] In the drawings of the embodiments disclosed in the present invention, only the structures related to the embodiments disclosed in the present invention are involved, and other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

[0083] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A diglyceride rich in polyunsaturated fatty acids, characterized in that: The invention comprises, by weight: 100-120 parts of natural vegetable oil, 25-35 parts of glycerol, 0.02-0.05 parts of antioxidant, 3-5 parts of catalyst and 10-15 parts of extraction co-solvent.

2. A diglyceride rich in polyunsaturated fatty acids according to claim 1, characterized in that: The natural vegetable oil is at least one of linseed oil, fish oil, linoleic acid, α-linolenic acid, DHA and EPA.

3. A diglyceride rich in polyunsaturated fatty acids according to claim 1, characterized in that: The antioxidant is natural tocopherol or rosemary extract.

4. A diglyceride rich in polyunsaturated fatty acids according to claim 1, characterized in that: The catalyst is a specific lipase, and the specific lipase includes at least one of Lipase TL IM and Novozym 435.

5. The method for preparing a diglyceride rich in polyunsaturated fatty acids according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Fatty acid extraction and enrichment: Use supercritical fluid extraction technology to separate and enrich polyunsaturated fatty acids from natural vegetable oils; S2, selective synthesis of diglyceride: esterifying the enriched polyunsaturated fatty acids with glycerol under the action of a catalyst to obtain diglyceride; S3, product purification: purifying the diglyceride by molecular distillation technology to remove impurities and obtain high-purity diglyceride; S4. Antioxidant treatment: adding antioxidants to the purified oil to obtain diglycerides rich in polyunsaturated fatty acids.

6. The method for preparing a diglyceride rich in polyunsaturated fatty acids according to claim 5, characterized in that: In the supercritical fluid extraction technology, the extraction medium is carbon dioxide, the operating pressure is 20-40 MPa, the temperature is 35-50° C., the co-solvent is ethanol, and the addition amount is 5%-15%.

7. The method for preparing a diglyceride rich in polyunsaturated fatty acids according to claim 5, characterized in that: The reaction conditions of the esterification reaction are: the molar ratio of glycerol to polyunsaturated fatty acids is 3:1 to 6:1, the reaction temperature is 25-45° C., the reaction time is 10-24 hours, and the reaction environment is a vacuum condition of 50-100 mbar.

8. The method for preparing a diglyceride rich in polyunsaturated fatty acids according to claim 5, characterized in that: The distillation temperature of the molecular distillation technology is 100-150° C., the distillation vacuum degree is 0.001-0.01 mbar, and the content of diglyceride after purification is more than 90%.

9. The method for preparing a diglyceride rich in polyunsaturated fatty acids according to claim 5, characterized in that: The antioxidant is natural tocopherol, and the added amount is 0.02%-0.05% of the total mass of the target product.

10. The method for preparing diglyceride rich in polyunsaturated fatty acids according to any one of claim 5, characterized in that: In the fatty acid composition of the diglyceride rich in polyunsaturated fatty acids, the polyunsaturated fatty acid content is 85%-98%, the diglyceride content is 90%-95%, the triglyceride content is not higher than 5%, and the monoglyceride content is 2%-3%.

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