Preparation method of diglyceride oil and application of akebia trifoliata in preparation of diglyceride oil

Abstract

The invention belongs to the technical field of food processing, and relates to a preparation method of diglyceride oil and application of akebia trifoliata in preparation of the diglyceride oil. The preparation method of the diglyceride oil comprises the following steps: (1) peeling ripe fruits of the akebia trifoliata, so as to obtain pulp of the akebia trifoliata; (2) performing separation treatment on the akebia fruit pulp obtained in the step (1) to obtain akebia fruit seeds; (3) performing cleaning and low-temperature drying treatment on the fried akebia trifoliata seeds obtained in the step (2); (4) performing low-temperature physical cold pressing treatment on the akebia trifoliata seeds treated in the step (3) to obtain cold-pressed crude oil; and (5) performing multiple filtration treatment on the cold-pressed crude oil obtained in the step (4) to obtain the high-purity diglyceride oil. The diglyceride oil is extracted from the natural akebia trifoliata seeds, and the low-temperature physical cold pressing and multiple filtering technologies are adopted, so that the quality of the diglyceride oil is ensured, and active ingredients are reserved to the greatest extent.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing and relates to a preparation method of diglyceride oil and application of fried tofu in the preparation of diglyceride oil. Background Art

[0002] Diacylceride (DAG) is a structural lipid in which a fatty acid in a triglyceride is replaced by a hydroxyl group. It is a trace component in natural plant oils and fats, and mainly exists as two isomers, 1,3-DAG and 1,2-DAG. Its content in common plants is usually less than 5%, and it is a recognized safe food ingredient. At the same time, diacylglyceride is a functional lipid with functions such as regulating blood lipids and preventing obesity. Currently, diacylglyceride (DAG) on the market is mainly synthesized and separated by chemical catalysis and lipase catalysis. However, the chemical catalysis method requires high temperature and organic solvents, and is prone to produce harmful byproducts (such as glycidyl esters); while the lipase catalysis method is costly and difficult to industrialize.

[0003] August fry, also known as August melon, is the banana-shaped fruit of the Akebia trifoliata plant. It is rich in sugar, vitamin C, and 12 amino acids, including valine, methionine, isoleucine, phenylalanine, and lysine, all of which cannot be synthesized by the human body. It has a sweet flavor and is a non-polluting, green food. The peel of the August fry has medicinal value, and the flesh can be used in medicine and beverages. The seeds, with their high oil content, can be used for oil extraction and can also be used as seeds for artificial cultivation.

[0004] The comprehensive utilization of August fried fruit is insufficient, with existing development limited to the flesh and peel. While August fried fruit seeds are known to have a high oil content and can be used for oil extraction, there's no clear application for this extraction. Furthermore, crude oil refining often involves high-temperature deodorization and chemical degumming, resulting in nutrient loss. Traditional filtration processes are ineffective in removing micron-sized impurities, impacting DAG purity.

[0005] Therefore, it is necessary to improve the extraction process of August fried seeds for the preparation of high value-added product diglyceride oil. Summary of the Invention

[0006] In response to the problems existing in the prior art, the present invention proposes a method for preparing diglyceride oil and the application of August fried in the preparation of diglyceride oil. The present invention improves the extraction process of August fried seeds for the preparation of diglyceride oil, a high value-added product.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] In a first aspect, the present invention provides a method for preparing diglyceride oil, the preparation method comprising the following steps:

[0009] (1) peeling the ripe August fried fruit to obtain August fried fruit pulp;

[0010] (2) separating the August fried fruit pulp obtained in step (1) to obtain August fried seeds;

[0011] (3) cleaning and low-temperature drying the August fried seeds obtained in step (2);

[0012] (4) performing a low-temperature physical cold pressing process on the August fried seeds obtained after the treatment in step (3) to obtain cold-pressed crude oil;

[0013] (5) performing multiple filtration treatments on the cold-pressed crude oil obtained in step (4) to obtain high-purity diglyceride oil.

[0014] Preferably, the low-temperature physical cold pressing includes flaking and pressing in sequence; wherein, flaking is to press the washed and low-temperature dried August fried seeds into thin slices with a thickness of 0.2-0.5 mm through a flaking machine; pressing is to extract oil by mechanical pressure under low temperature conditions, with the temperature controlled at 40-60°C, to maximize the retention of heat-sensitive components.

[0015] The flaking temperature is 40-60°C;

[0016] The pressing temperature is 40-60° C. and the pressing time is 10-20 minutes.

[0017] Preferably, the squeezing pressure is adjusted in stages, specifically:

[0018] The pressure in the first stage is 10-15 MPa;

[0019] The pressure in the second stage is 20-25MPa;

[0020] The pressure in the third stage is 30-35MPa.

[0021] Preferably, the multiple filtrations include primary filtration, secondary filtration, deep filtration and terminal filtration in sequence.

[0022] Preferably,

[0023] The primary filtration equipment is a vibrating screen or a plate and frame filter, the pore size of the filter cloth is 100-200 mesh, and the temperature is ≤40°C;

[0024] The equipment for the intermediate filtration is a centrifuge or a bag filter, and the pore size of the filter material is 5-20 μm;

[0025] The depth filtration equipment is a membrane filtration system, and the pore size of the filter membrane is 0.1-1 μm;

[0026] The terminal filtration device is a precision filter element with a pore size of 1-5 μm.

[0027] Preferably,

[0028] The primary filtration is used to remove the August fried seed debris and large particle impurities remaining after pressing;

[0029] The intermediate filtration is used to separate fine suspended matter and some colloidal substances;

[0030] The depth filtration is used to intercept micron-sized particles, colloids and some free fatty acids;

[0031] The terminal filtration is used to ensure the cleanliness of diglyceride before filling and to prevent impurities from remaining in the pipeline.

[0032] Preferably, the purity of the diglyceride oil is ≥90%.

[0033] Preferably, the vitamin E retention rate in the cold-pressed crude oil is ≥90%, and the polyphenol retention rate in the cold-pressed crude oil is ≥85%.

[0034] It should be noted that, on the one hand, the traditional production of safflower oil typically requires a refining process, which fails to preserve the oil's natural active ingredients and does not enrich diacylglycerols. On the other hand, the traditional production of safflower oil typically involves chemical degumming and high-temperature treatment, which can easily lead to diacylglycerol degradation and introduce safety risks. Furthermore, the traditional production of safflower oil lacks a multi-stage physical filtration system or only uses a single filtration system, making it impossible to balance impurity removal and nutrient retention.

[0035] In a second aspect, the present invention provides an application of the preparation method of the present invention in improving the purity of diglyceride oil, improving the vitamin E retention rate in cold-pressed crude oil, and / or improving the polyphenol retention rate in cold-pressed crude oil.

[0036] A third aspect provides the use of mulberry and / or mulberry seeds in the preparation of diglyceride oil.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] (1) The present invention uses natural August fried seed oil to extract diglyceride oil, and adopts low-temperature physical cold pressing and multiple filtration technology to improve the purity of diglyceride, while ensuring the quality of diglyceride oil and retaining the active ingredients to the greatest extent. Specifically, through the low-temperature physical cold pressing process, August fried seed oil significantly improves the retention rate of functional ingredients (such as vitamin E and polyphenols) while avoiding high-temperature oxidation, and effectively inhibits the generation of harmful by-products such as glycidyl esters; combined with the subsequent multiple filtration process, the oil quality and the high purity of diglyceride oil (≥90%) are further ensured, providing a feasible solution for industrial production. Among them, the purity of diglyceride is ≥90%, the vitamin E retention rate in the pressed crude oil is ≥90%, and the polyphenol retention rate in the pressed crude oil is ≥85%.

[0039] (2) The present invention utilizes August fried seeds to prepare high value-added products, avoids the introduction of non-edible chemical reagents, improves the yield and preparation efficiency of diglyceride oil (separation efficiency is increased to more than 500 kg / h), and reduces costs. DETAILED DESCRIPTION

[0040] The present invention will be described in detail below in conjunction with specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly presented. It should be understood by those skilled in the art that these specific embodiments and examples are for illustrating the present invention, rather than limiting the present invention.

[0041] The following examples illustrate the technical solutions of the present invention, but the present invention is not limited to the following examples. The experimental methods and detection methods described in each example are conventional methods unless otherwise specified; the reagents and materials are commercially available unless otherwise specified.

[0042] Example 1

[0043] This embodiment provides a method for preparing diglyceride oil, which comprises the following steps:

[0044] (1) peeling the ripe August fried fruit to obtain August fried fruit pulp;

[0045] (2) separating the August fried fruit pulp obtained in step (1) to obtain August fried seeds;

[0046] (3) cleaning and low-temperature drying the August fried seeds obtained in step (2);

[0047] (4) performing a low-temperature physical cold pressing process on the August fried seeds obtained after the treatment in step (3) to obtain cold-pressed crude oil;

[0048] (5) performing multiple filtration treatments on the cold-pressed crude oil obtained in step (4) to obtain high-purity diglyceride oil;

[0049] The low-temperature physical cold pressing includes flaking and pressing in sequence; wherein, flaking is to press the washed and low-temperature dried August fried seeds into thin slices with a thickness of 0.2-0.5 mm through a flaking machine; pressing is to extract the oil by mechanical pressure under low temperature conditions, with the temperature controlled at 40°C, to maximize the retention of heat-sensitive components;

[0050] The flaking temperature is 40°C;

[0051] The pressing temperature is 40°C and the pressing time is 10 minutes;

[0052] The squeezing pressure is adjusted in stages, specifically:

[0053] The pressure in the first stage is 10 MPa;

[0054] The pressure in the second stage is 20 MPa;

[0055] The pressure of the third stage is 30MPa;

[0056] The multiple filtrations include primary filtration, intermediate filtration, deep filtration and terminal filtration in sequence;

[0057] The primary filtration equipment is a vibrating screen or a plate and frame filter, the pore size of the filter cloth is 100-200 mesh, and the temperature is ≤40°C;

[0058] The intermediate filtration equipment is a centrifuge or a bag filter, and the pore size of the filter material is 5 μm;

[0059] The depth filtration equipment is a membrane filtration system, and the pore size of the filter membrane is 0.1 μm;

[0060] The terminal filtration device is a precision filter element with a pore size of 1 μm;

[0061] The primary filtration is used to remove the August fried seed debris and large particle impurities remaining after pressing;

[0062] The intermediate filtration is used to separate fine suspended matter and some colloidal substances;

[0063] The depth filtration is used to intercept micron-sized particles, colloids and some free fatty acids;

[0064] The terminal filtration is used to ensure the cleanliness of diglyceride before filling and to prevent impurities from remaining in the pipeline;

[0065] The purity of the diglyceride oil is ≥91%.

[0066] The vitamin E retention rate in the cold-pressed crude oil is ≥91%, and the polyphenol retention rate in the cold-pressed crude oil is ≥86%.

[0067] Example 2

[0068] This embodiment provides a method for preparing diglyceride oil, which comprises the following steps:

[0069] (1) peeling the ripe August fried fruit to obtain August fried fruit pulp;

[0070] (2) separating the August fried fruit pulp obtained in step (1) to obtain August fried seeds;

[0071] (3) cleaning and low-temperature drying the August fried seeds obtained in step (2);

[0072] (4) performing a low-temperature physical cold pressing process on the August fried seeds obtained after the treatment in step (3) to obtain cold-pressed crude oil;

[0073] (5) performing multiple filtration treatments on the cold-pressed crude oil obtained in step (4) to obtain high-purity diglyceride oil;

[0074] The low-temperature physical cold pressing includes flaking and pressing in sequence; wherein, flaking is to press the washed and low-temperature dried August fried seeds into thin slices with a thickness of 0.2-0.5 mm through a flaking machine; pressing is to extract the oil by mechanical pressure under low temperature conditions, with the temperature controlled at 60°C, to maximize the retention of heat-sensitive components;

[0075] The flaking temperature is 60°C;

[0076] The pressing temperature is 60°C and the pressing time is 20 minutes;

[0077] The squeezing pressure is adjusted in stages, specifically:

[0078] The pressure in the first stage is 15 MPa;

[0079] The pressure in the second stage is 25 MPa;

[0080] The pressure of the third stage is 35MPa;

[0081] The multiple filtrations include primary filtration, intermediate filtration, deep filtration and terminal filtration in sequence;

[0082] The primary filtration equipment is a vibrating screen or a plate and frame filter, the pore size of the filter cloth is 100-200 mesh, and the temperature is ≤40°C;

[0083] The intermediate filtration equipment is a centrifuge or a bag filter, and the pore size of the filter material is 20 μm;

[0084] The depth filtration equipment is a membrane filtration system, and the pore size of the filter membrane is 1 μm;

[0085] The terminal filtration equipment is a precision filter element with a pore size of 5 μm;

[0086] The primary filtration is used to remove the August fried seed debris and large particle impurities remaining after pressing;

[0087] The intermediate filtration is used to separate fine suspended matter and some colloidal substances;

[0088] The depth filtration is used to intercept micron-sized particles, colloids and some free fatty acids;

[0089] The terminal filtration is used to ensure the cleanliness of diglyceride before filling and to prevent impurities from remaining in the pipeline;

[0090] The purity of the diglyceride oil is ≥90%;

[0091] The vitamin E retention rate in the cold-pressed crude oil is ≥92%, and the polyphenol retention rate in the cold-pressed crude oil is ≥88%.

[0092] Example 3

[0093] This embodiment provides a method for preparing diglyceride oil, which comprises the following steps:

[0094] (1) peeling the ripe August fried fruit to obtain August fried fruit pulp;

[0095] (2) separating the August fried fruit pulp obtained in step (1) to obtain August fried seeds;

[0096] (3) cleaning and low-temperature drying the August fried seeds obtained in step (2);

[0097] (4) performing a low-temperature physical cold pressing process on the August fried seeds obtained after the treatment in step (3) to obtain cold-pressed crude oil;

[0098] (5) performing multiple filtration treatments on the cold-pressed crude oil obtained in step (4) to obtain high-purity diglyceride oil;

[0099] The low-temperature physical cold pressing includes flaking and pressing in sequence; wherein, flaking is to press the washed and low-temperature dried August fried seeds into thin slices with a thickness of 0.2-0.5 mm through a flaking machine; pressing is to extract the oil by mechanical pressure under low-temperature conditions, with the temperature controlled at 55°C, to maximize the retention of heat-sensitive components;

[0100] The flaking temperature is 50°C;

[0101] The pressing temperature is 55°C and the pressing time is 15 minutes;

[0102] The squeezing pressure is adjusted in stages, specifically:

[0103] The pressure in the first stage is 15 MPa;

[0104] The pressure in the second stage is 20 MPa;

[0105] The pressure of the third stage is 35MPa;

[0106] The multiple filtrations include primary filtration, intermediate filtration, deep filtration and terminal filtration in sequence;

[0107] The primary filtration equipment is a vibrating screen or a plate and frame filter, the pore size of the filter cloth is 100-200 mesh, and the temperature is ≤40°C;

[0108] The intermediate filtration equipment is a centrifuge or a bag filter, and the pore size of the filter material is 5 μm;

[0109] The depth filtration equipment is a membrane filtration system, and the pore size of the filter membrane is 1 μm;

[0110] The terminal filtration equipment is a precision filter element with a pore size of 5 μm;

[0111] The primary filtration is used to remove the August fried seed debris and large particle impurities remaining after pressing;

[0112] The intermediate filtration is used to separate fine suspended matter and some colloidal substances;

[0113] The depth filtration is used to intercept micron-sized particles, colloids and some free fatty acids;

[0114] The terminal filtration is used to ensure the cleanliness of diglyceride before filling and to prevent impurities from remaining in the pipeline;

[0115] The purity of the diglyceride oil is ≥92%;

[0116] The vitamin E retention rate in the cold-pressed crude oil is ≥93%, and the polyphenol retention rate in the cold-pressed crude oil is ≥90%.

[0117] Comparative Example 1

[0118] This comparative example is the same as Example 3, except that the low-temperature physical cold pressing process is adjusted as follows:

[0119] The low-temperature physical cold pressing includes rolling, steaming, pressing and leaching in sequence; the leaching is specifically: soaking the seed cake with solvent oil, then evaporating the solvent oil at high temperature and recycling it for reuse, and the crude oil left after evaporation is subjected to subsequent multiple filtration treatments.

[0120] Comparative Example 2

[0121] This comparative example is the same as Example 3, except that it does not include intermediate filtration, depth filtration or terminal filtration.

[0122] Comparative Example 3

[0123] The diglyceride oil was prepared by the chemical catalysis method and was sold commercially (Guangdong Shanbainian Special Medical Food Co., Ltd.).

[0124] Comparative Example 4

[0125] The diglyceride oil was prepared by the lipase catalysis method and was sold commercially (Guangdong Shanbainian Special Medical Food Co., Ltd.).

[0126] Effect verification

[0127] Experimental subjects: diglyceride oils prepared in Examples 1-3 and Comparative Examples 1-4;

[0128] Experimental methods:

[0129] 1) Purity test of diglyceride oil:

[0130] Referring to GB / T 26636-2011 "Determination of polymerized triglycerides in animal and vegetable oils - High performance size exclusion chromatography (HPSEC)", the percentage of DAG peak area in the diacylglycerol oil sample to all acylglycerides was calculated, which is the purity of the diacylglycerol oil.

[0131] 2) Vitamin E retention rate test in crude oil:

[0132] Refer to GB 5009.82-2016 "Determination of vitamins A, D and E in foods".

[0133] 3) Polyphenol retention rate test in crude oil:

[0134] Gallic acid was prepared into a series of concentrations of 50-500 μg / mL, and Folin phenol reagent and sodium carbonate solution were added. The mixture was reacted in the dark for 30 minutes, and the absorbance at 765 nm was measured to draw a standard curve.

[0135] Weigh 0.5 g of crude oil and add 5 mL of methanol-acetone-water (5:5:1, v / v / v) mixed solvent, and add 0.1% (w / v) ascorbic acid. Shake and extract for 10 min. Centrifuge at 4000 rpm for 10 min at 4°C. Collect the supernatant for later use.

[0136] Take 1 mL of the supernatant, add 0.5 mL of Folin phenol reagent, mix well and let stand for 5 min, then add 4 mL of 7.5% sodium carbonate solution, dilute to 25 mL, react in the dark for 1 h (reaction temperature is 25 ± 1 ° C), measure the absorbance, and calculate the polyphenol content according to the standard curve;

[0137] Retention rate = polyphenol content of cold-pressed crude oil / polyphenol content of August fried seeds before cold pressing × 100%;

[0138] Among them, the polyphenol content of August fried seeds needs to be determined simultaneously before cold pressing: take the unprocessed August fried seeds, grind them, and then follow the same extraction and determination methods.

[0139] 4) Separation efficiency test:

[0140] Continuously process 500 kg of fresh August fried fruit, record the separation efficiency and seed recovery rate every 100 kg, and calculate the average value and RSD (should be less than 5%).

[0141] Weigh 100 kg of fresh August fried fruit and record the total mass (Mtotal);

[0142] Turn on the equipment (separator speed: 2000 r / min, temperature ≤ 30°C), put the fruit into the separation line, collect the mass of the seeds (Mseeds), peel (Mpeel), and flesh (Mflesh) after separation, and record the processing time (t, unit: h);

[0143] Separation efficiency (kg / h): Mtotal / t;

[0144] Seed recovery rate (%): M seeds / (M total × theoretical seed ratio) × 100%;

[0145] Equipment separation efficiency ≥500kg / h, seed recovery rate ≥95% is qualified;

[0146] Among them, the steps for determining the theoretical seed ratio are: randomly select 100 kg of mature August-exploded fruits, manually separate the seeds, peel, and pulp, weigh and calculate the actual seed ratio (such as M seeds measured / M total × 100%), repeat 3 times and take the average value as the theoretical seed ratio.

[0147] 5) Cost calculation:

[0148] The total cost of diglyceride oil product per unit is calculated as follows: the raw material cost per unit of diglyceride oil product + the labor cost per unit of diglyceride oil product + the energy cost per unit of diglyceride oil product + the equipment depreciation cost per unit of diglyceride oil product + the other costs per unit of diglyceride oil product; among which,

[0149] The cost of raw materials is calculated as "(unit price of fruit × input amount) / oil output";

[0150] Labor costs are calculated as "(number of workers operating a single batch × average hourly wage × single batch processing time) / single batch diglyceride oil output";

[0151] Energy consumption cost is calculated as "(total equipment power × operating time × electricity price) / single batch diglyceride oil production";

[0152] Equipment depreciation cost is calculated as "(total equipment investment × annual depreciation rate) / annual production capacity";

[0153] Other costs are calculated as "(filter consumables cost + packaging material cost + testing fee) / single batch diglyceride oil output".

[0154] Experimental results: as shown in Table 1.

[0155] Table 1 Test results of diglyceride oil quality in each group

[0156]

[0157] As shown in Table 1, the diglyceride oils prepared in Examples 1-3 of the present invention had a purity of 90-92%, a vitamin E retention rate in the crude oil of 91-93%, a polyphenol retention rate in the crude oil of 86-90%, and a separation efficiency of 500-520 kg / h. The diglyceride oils prepared in Comparative Examples 1-2 had a purity of 43-46%, a vitamin E retention rate in the crude oil of 50-52%, and a polyphenol retention rate in the crude oil of 43-45%. The diglyceride oils prepared in Comparative Examples 3-4 had a purity of 65-76%, a vitamin E retention rate in the crude oil of 41-52%, and a polyphenol retention rate in the crude oil of 25-45%. Overall, the diglyceride oils prepared in Examples 1-3 of the present invention were of superior quality, with the diglyceride oil prepared in Example 3 having the best quality.

[0158] It can be seen that the present invention uses natural August fried seed to extract diglyceride oil, and adopts low-temperature physical cold pressing and multiple filtration technology to obtain a very high purity of diglyceride oil, while ensuring the quality of diglyceride oil and retaining the active ingredients to the greatest extent. Specifically, through the low-temperature physical cold pressing process, August fried seed oil significantly improves the retention rate of functional ingredients (such as vitamin E and polyphenols) while avoiding high-temperature oxidation, and effectively suppresses the formation of harmful byproducts such as glycidyl esters; combined with the subsequent multiple filtration process, the quality of the oil and the high purity of the diglyceride oil are further ensured, providing a feasible solution for industrial production. The present invention uses August fried seed to prepare high-value-added products, avoids the introduction of non-edible chemical reagents, improves the yield and preparation efficiency of diglyceride oil, and reduces costs.

[0159] It should be understood that the present invention disclosed is not limited only to the specific method, scheme and material of description, because these all can change.It should also be understood that the term used herein is only for the purpose of describing specific embodiment scheme, rather than being intended to limit the scope of the present invention, and the scope of the present invention is only limited to the appended claims.

Claims

1. A method for preparing diglyceride oil, characterized in that: The preparation method comprises the following steps: (1) peeling the ripe August fried fruit to obtain August fried fruit pulp; (2) separating the August fried fruit pulp obtained in step (1) to obtain August fried seeds; (3) cleaning and low-temperature drying the August fried seeds obtained in step (2); (4) performing a low-temperature physical cold pressing process on the August fried seeds obtained after the treatment in step (3) to obtain cold-pressed crude oil; (5) performing multiple filtration treatments on the cold-pressed crude oil obtained in step (4) to obtain high-purity diglyceride oil.

2. The preparation method according to claim 1, characterized in that The low-temperature physical cold pressing includes flaking and pressing in sequence; wherein, The temperature of the flaking is 40-60°C; The pressing temperature is 40-60° C. and the pressing time is 10-20 minutes.

3. The preparation method according to claim 2, characterized in that The squeezing pressure is adjusted in stages, specifically: The pressure in the first stage is 10-15 MPa; The pressure in the second stage is 20-25MPa; The pressure in the third stage is 30-35MPa.

4. The preparation method according to claim 1, characterized in that The multiple filtrations include primary filtration, intermediate filtration, deep filtration and terminal filtration in sequence.

5. The preparation method according to claim 4, characterized in that The primary filtration equipment is a vibrating screen or a plate and frame filter, the pore size of the filter cloth is 100-200 mesh, and the temperature is ≤40°C; The equipment for the intermediate filtration is a centrifuge or a bag filter, and the pore size of the filter material is 5-20 μm; The depth filtration equipment is a membrane filtration system, and the pore size of the filter membrane is 0.1-1 μm; The terminal filtration device is a precision filter element with a pore size of 1-5 μm.

6. The preparation method according to claim 5, characterized in that The primary filtration is used to remove the August fried seed debris and large particle impurities remaining after pressing; The intermediate filtration is used to separate fine suspended matter and some colloidal substances; The depth filtration is used to intercept micron-sized particles, colloids and some free fatty acids; The terminal filtration is used to ensure the cleanliness of diglyceride before filling and to prevent impurities from remaining in the pipeline.

7. The preparation method according to claim 6, characterized in that The purity of the diglyceride oil is ≥90%.

8. The preparation method according to claim 6, characterized in that The vitamin E retention rate in the cold-pressed crude oil is ≥90%, and the polyphenol retention rate in the cold-pressed crude oil is ≥85%.

9. Use of the preparation method according to any one of claims 1 to 8 in improving the purity of diglyceride oil, improving the vitamin E retention rate in cold-pressed crude oil, and / or improving the polyphenol retention rate in cold-pressed crude oil.

10. Use of mulberry leaf and / or mulberry leaf seeds in the preparation of diglyceride oil.

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