Low-temperature physical purification method of high-purity nutritional purple perilla seed oil

Abstract

The invention relates to the technical field of vegetable oil refining and processing, and discloses a low-temperature physical purification method of high-purity nutritional purple perilla seed oil, which comprises the following steps: S1, freezing crude purple perilla seed oil subjected to filtration and impurity removal at-30 DEG C to-20 DEG C for 36-50 hours to separate out wax and free water crystals in the oil; s2, the frozen purple perilla seed oil is subjected to three-stage filtration through precision filter materials of 5 micrometers, 1 micrometer and 0.1 micrometer in sequence in the low-temperature state, whole-process low-temperature physical purification is adopted, heating, chemical reagents and adsorption decoloration are avoided, nutritional ingredients such as alpha-linolenic acid and vitamin E are well reserved, trans-fatty acid is not generated, the nutrition and safety are higher, and the method is suitable for industrial production. Through low-temperature crystallization, multi-stage precision filtration and nanofiltration membrane cross-flow coupling, wax, water, phospholipid and other impurities can be thoroughly removed, an oil product is clear and stable and is not liable to become turbid and deteriorate, the process is green and environment-friendly, the cost is low, the method is suitable for industrial production, and the problem that the quality of traditional refining and existing physical purification is poor is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of vegetable oil refining and processing technology, specifically to a low-temperature physical purification method for high-purity, nutritious perilla seed oil. Background Technology

[0002] Perilla seed oil is rich in polyunsaturated fatty acids such as alpha-linolenic acid, and has extremely high nutritional and health value. However, because unsaturated fatty acids are highly reactive, they are easily oxidized and degraded under high temperatures and chemical reagents, leading to a decrease in their physiological activity.

[0003] Currently, traditional perilla seed oil refining mostly uses chemical refining processes, which require the addition of phosphoric acid and sodium hydroxide for degumming and deacidification, and the use of high-temperature adsorption and decolorization with bleaching clay. Although this process can remove gums, waxes and free fatty acids from the crude oil, the high-temperature treatment and the use of chemical reagents will cause irreversible damage to the oil, resulting in a large loss of natural nutrients such as vitamin E and phytosterols, and even the production of trans fatty acids, which seriously affects the natural quality of perilla seed oil as a high-end nutritional oil.

[0004] Existing physical refining methods often only achieve simple filtration and are insufficient to completely remove waxes, water, and colloidal substances that crystallize out at low temperatures without heating or adding chemical reagents. This results in the finished oil becoming cloudy or oxidized during storage, failing to meet the market demand for high-purity, high-nutrient cold-pressed perilla seed oil. Therefore, we propose a low-temperature physical purification method for high-purity, nutritious perilla seed oil to solve the aforementioned problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a low-temperature physical purification method for high-purity, nutritious perilla seed oil. This method solves the problems of nutrient loss and trans fatty acid production caused by high temperatures and reagents in traditional chemical refining, as well as the incomplete purification and easy turbidity and oxidation of the oil in existing physical refining methods.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a low-temperature physical purification method for high-purity nutritional perilla seed oil, comprising the following steps:

[0007] S1. Place the filtered and impurity-removed crude perilla seed oil at -30℃ to -20℃ for 36-50 hours to allow the wax and free water in the oil to crystallize out.

[0008] S2. The frozen perilla seed oil is filtered in three stages at low temperature through precision filter media of 5μm, 1μm and 0.1μm to remove crystalline wax and water, while also filtering out some phospholipids and free fatty acids.

[0009] S3. Let the filtered perilla seed oil stand at room temperature for 10-14 hours;

[0010] S4. After standing, the perilla seed oil is filtered through a nanofiltration membrane to completely remove phospholipids and free fatty acids from the oil, thus obtaining high-purity perilla seed oil.

[0011] Preferably, in step S1, the freezing temperature is -25°C and the freezing time is 48 hours.

[0012] Preferably, in step S2, the three-stage filtration process is carried out entirely at a low temperature of -25°C.

[0013] Preferably, the nanofiltration membrane has a molecular weight cutoff of 2000–3000 Daltons.

[0014] Preferably, in step S2, the precision filter material is a polytetrafluoroethylene pleated filter element.

[0015] Preferably, after step S4, the process further includes: sterile nitrogen-filling the purified perilla seed oil to obtain the finished high-purity nutritious perilla seed oil.

[0016] Preferably, the entire purification process does not involve heating, adding chemical reagents, or using adsorption and decolorizing agents.

[0017] Preferably, the filtration in S4 adopts cross-flow filtration to delay membrane fouling and improve filtration efficiency.

[0018] Beneficial effects

[0019] This invention provides a low-temperature physical purification method for high-purity, nutritious perilla seed oil. Compared with existing technologies, it has the following advantages:

[0020] This high-purity, nutritious perilla seed oil utilizes a low-temperature physical purification method. This process completely eliminates traditional chemical refining and high-temperature treatment steps, maximizing the preservation of the natural nutrients and physiological activity of the perilla seed oil. The purification process involves no heating, no addition of chemical reagents such as phosphoric acid or sodium hydroxide, and no use of adsorbents or decolorizing agents such as bleaching clay. This effectively prevents the oxidative degradation of α-linolenic acid, fully preserving natural vitamin E, phytosterols, squalene, and other active substances. It does not produce trans fatty acids, resulting in a significantly higher nutrient retention rate and greater food safety compared to traditional processes, fully meeting the quality requirements of high-end nutritious oils.

[0021] By coupling low-temperature crystallization, three-stage precision filtration, and nanofiltration membrane cross-flow filtration technology, this process achieves highly efficient impurity removal, significantly improving purification efficiency and stability. It thoroughly removes waxes, free water, phospholipids, free fatty acids, and colloidal impurities, resulting in a clear, transparent, and non-turbid oil at low temperatures. Cross-flow filtration slows down membrane fouling and improves filtration efficiency. Combined with aseptic nitrogen filling, it effectively reduces oxidation rates and extends shelf life. Simultaneously, the process generates no chemical waste liquid or residue, making it environmentally friendly, cost-effective, and suitable for continuous industrial production. It addresses the industry pain points of incomplete physical refining and purification, and the tendency for oils to become turbid and deteriorate. Attached Figure Description

[0022] Figure 1 This is a flowchart of a low-temperature physical purification method for high-purity, nutritious perilla seed oil according to the present invention. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] like Figure 1 As shown:

[0025] A low-temperature physical purification method for high-purity, nutritious perilla seed oil includes the following steps:

[0026] S1. Place the crude perilla seed oil that has undergone preliminary filtration and impurity removal into a low-temperature freezing device, control the temperature at -30℃ to -20℃, and freeze continuously for 36-50 hours to allow the wax and free water in the oil to crystallize and be fully separated, laying the foundation for subsequent filtration and separation.

[0027] As a preferred option, in this S1, the freezing temperature is set to -25°C and the freezing time is 48 hours. These parameters can maximize the crystallization rate of wax and free water, while avoiding excessive solidification of the oil and affecting its fluidity.

[0028] S2. Keep the frozen perilla seed oil at a low temperature and filter it through three levels of precision filter media: 5μm, 1μm, and 0.1μm. Maintain the filtration environment temperature consistent with the freezing temperature throughout the process to thoroughly intercept and remove crystalline wax, free water, and large colloidal impurities. It can also filter out some phospholipids and free fatty acids.

[0029] As a preferred option, the three-stage filtration process is carried out entirely in a low-temperature environment of -25℃; the precision filter material uses a polytetrafluoroethylene pleated filter element, which has the characteristics of low temperature resistance, anti-clogging, and stable filtration accuracy, making it suitable for the low-temperature filtration conditions of perilla seed oil.

[0030] S3. Transfer the low-temperature filtered perilla seed oil to a sealed container and let it stand for 10-14 hours under normal temperature and pressure conditions to allow the oil temperature to slowly rise to room temperature, eliminate low-temperature internal stress, restore the oil to a uniform and stable state, and avoid the subsequent membrane filtration efficiency reduction due to sudden temperature changes.

[0031] S4. After standing, the perilla seed oil is filtered through a nanofiltration membrane to completely remove small molecule impurities such as residual phospholipids and free fatty acids from the oil, thus obtaining high-purity perilla seed oil.

[0032] As a preferred option, nanofiltration membranes have a molecular weight cutoff of 2000-3000 Daltons, which can accurately retain phospholipids and free fatty acids while retaining nutrients such as α-linolenic acid and vitamin E. This filtration step adopts a cross-flow filtration method, in which the feed liquid flows parallel to the membrane surface, and the shear force is used to reduce solute adsorption and deposition, delay membrane fouling, extend membrane life and improve filtration efficiency.

[0033] S5. The purified high-purity perilla seed oil is transported to the aseptic filling line for aseptic nitrogen filling to isolate oxygen, prevent oxidation, extend the shelf life of the finished product, and finally obtain the high-purity nutritional perilla seed oil product.

[0034] The core technological features of this invention are: the entire purification process does not involve heating, adding any chemical reagents, or using adsorption and decolorizing agents such as clay; the entire process employs physical separation and purification methods to maximize the preservation of the natural nutrients and activity of perilla seed oil.

[0035] Example 1:

[0036] A low-temperature physical purification method for high-purity, nutritious perilla seed oil, comprising the following steps:

[0037] S1. Place the filtered and impurity-removed crude perilla seed oil into a freezing crystallization tank, set the temperature to -25℃, and freeze for 48 hours to allow the wax and free water to crystallize and precipitate completely.

[0038] S2. Start the low-temperature three-stage filtration unit and maintain the ambient temperature at -25℃. Pass the filter through 5μm, 1μm, and 0.1μm polytetrafluoroethylene pleated filter elements in sequence to remove crystalline wax and moisture.

[0039] S3. Transfer the filtered oil to a room temperature settling tank and let it stand at room temperature for 12 hours.

[0040] S4. Pump the oil into the nanofiltration membrane filtration device, using a nanofiltration membrane module with a molecular weight cutoff of 2500 Daltons, and turn on the cross-flow circulation pump to perform cross-flow filtration to remove phospholipids and free fatty acids.

[0041] S5. The purified oil is transported to the aseptic nitrogen filling machine to complete the aseptic nitrogen filling and obtain the finished product.

[0042] This method employs a fully low-temperature physical purification process, completely eliminating traditional chemical refining and high-temperature treatment steps, thus maximizing the preservation of the natural nutrients and physiological activities of perilla seed oil. The purification process involves no heating, no addition of chemical reagents such as phosphoric acid or sodium hydroxide, and no use of adsorption and decolorizing agents such as bleaching clay. This effectively prevents the oxidative degradation of α-linolenic acid, fully preserving natural vitamin E, phytosterols, squalene, and other active substances, without producing trans fatty acids. The oil's nutrient retention rate and food safety are significantly superior to traditional processes, fully meeting the quality requirements of high-end nutritional oils.

[0043] By coupling low-temperature crystallization, three-stage precision filtration, and nanofiltration membrane cross-flow filtration technology, this process achieves highly efficient impurity removal, significantly improving purification efficiency and stability. It thoroughly removes waxes, free water, phospholipids, free fatty acids, and colloidal impurities, resulting in a clear, transparent, and non-turbid oil at low temperatures. Cross-flow filtration slows down membrane fouling and improves filtration efficiency. Combined with aseptic nitrogen filling, it effectively reduces oxidation rates and extends shelf life. Simultaneously, the process generates no chemical waste liquid or residue, making it environmentally friendly, cost-effective, and suitable for continuous industrial production. It addresses the industry pain points of incomplete physical refining and purification, and the tendency for oils to become turbid and deteriorate.

[0044] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-temperature physical purification method for high-purity, nutritious perilla seed oil, characterized in that: Includes the following steps: S1. Place the filtered and impurity-removed crude perilla seed oil at -30℃ to -20℃ for 36-50 hours to allow the wax and free water in the oil to crystallize out. S2. The frozen perilla seed oil is filtered in three stages at low temperature through precision filter media of 5μm, 1μm and 0.1μm to remove crystalline wax and water, while also filtering out some phospholipids and free fatty acids. S3. Let the filtered perilla seed oil stand at room temperature for 10-14 hours; S4. After standing, the perilla seed oil is filtered through a nanofiltration membrane to completely remove phospholipids and free fatty acids from the oil, thus obtaining high-purity perilla seed oil.

2. The low-temperature physical purification method for high-purity nutritional perilla seed oil according to claim 1, characterized in that: In S1, the freezing temperature is -25°C and the freezing time is 48 hours.

3. The low-temperature physical purification method for high-purity nutritional perilla seed oil according to claim 2, characterized in that: In step S2, the three-stage filtration process is carried out entirely at a low temperature of -25°C.

4. The low-temperature physical purification method for high-purity nutritional perilla seed oil according to claim 1, characterized in that: The nanofiltration membrane has a molecular weight cutoff of 2000–3000 Daltons.

5. The low-temperature physical purification method for high-purity nutritional perilla seed oil according to claim 1, characterized in that: In S2, the precision filter material is a polytetrafluoroethylene pleated filter element.

6. The low-temperature physical purification method for high-purity nutritional perilla seed oil according to claim 1, characterized in that: The process after S4 includes: sterile nitrogen-filling the purified perilla seed oil to obtain the finished high-purity nutritional perilla seed oil.

7. The low-temperature physical purification method for high-purity nutritional perilla seed oil according to claim 1, characterized in that: The entire purification process involves no heating, no addition of chemical reagents, and no use of adsorption or decolorizing agents.

8. The low-temperature physical purification method for high-purity nutritional perilla seed oil according to claim 1, characterized in that: The filtration in S4 employs cross-flow filtration to delay membrane fouling and improve filtration efficiency.

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