Low-temperature pneumatic solvent-free extraction process of active ingredients of plants and animals

Abstract

The application discloses a low-temperature pneumatic solvent-free extraction process of active ingredients of animals and plants and relates to the technical field of oil and fat and fat-soluble active ingredient extraction. Oil-containing animal and plant raw materials are coarsely crushed and then loaded into a pressure extraction cavity, inert gas is introduced and pressure is kept under the condition that no liquid extractant is added and the oil of the raw materials keeps flowing at low temperature; after the pressure keeping is finished, the gas source is cut off, limited pressure relief is carried out through the liquid discharge side to keep negative pressure, and the gas-containing oil liquid is gathered to the liquid discharge side; the residual negative pressure formed by the same pressurization is used to continue discharging through the first transfer, separate pressure reduction of the liquid collecting cavity and the second transfer; after the two cavities are cut off, the first stage pressure reduction and the second stage intermittent pressure reduction are carried out on the gas-containing oil liquid in the liquid collecting cavity, and then centrifugal separation is carried out to obtain oil phase containing fat-soluble active ingredients. The process completes the transfer in batches without re-increasing the negative pressure of the raw material side, and reduces the foam and emulsification caused by the rapid pressure reduction of the gas-containing oil liquid.

Description

Technical Field

[0001] This invention relates to the field of oil and fat extraction technology, specifically to a low-temperature pneumatic solventless extraction process for obtaining an oil phase containing fat-soluble active ingredients from oily plant and animal raw materials by using inert gas pressurization, limited pressure relief, residual negative pressure transfer in stages, and independent segmented degassing. Background Technology

[0002] Oil-bearing plant seeds, oil-bearing fruit pulp, and fatty tissues of animals typically contain fat-soluble active ingredients such as tocopherols, phytosterols, carotenoids, and polyunsaturated fatty acids. Current oil extraction processes mainly include mechanical pressing, liquid solvent extraction, and supercritical fluid extraction. Mechanical pressing relies on continuous mechanical load; at low temperatures, when oil viscosity increases, the oil tends to remain trapped in the raw material particles and drainage path. While increasing the pressing temperature can reduce viscosity, it increases the loss of heat-sensitive components and the risk of oil oxidation.

[0003] Liquid solvent leaching can improve oil extraction rates, but solvent recovery and residue control are required, and subsequent concentration of the extract increases energy consumption. Supercritical fluid extraction requires maintaining specific fluid states and continuous fluid circulation, making the equipment's negative pressure level, operation control, and separation conditions more complex. For raw materials with high water content, pectin content, or high protein content, the oil phase, water phase, fine solids, and bubbles can easily form an emulsion system, increasing the difficulty of subsequent oil-water separation. Summary of the Invention

[0004] The purpose of this invention is to provide a low-temperature pneumatic solventless extraction process for active ingredients from plants and animals, in order to solve the problems of lack of continuous transfer power after oil release under low-temperature conditions without liquid extractant, oil retention in the raw material bed, and easy generation of foam and emulsification when the gas-containing oil is rapidly depressurized.

[0005] To achieve the above objectives, the present invention provides a low-temperature pneumatic solvent-free extraction process for active ingredients from plants and animals, comprising the following steps: S1. The oil-containing animal and plant raw materials are coarsely crushed to obtain raw material particles, and the raw material particles are loaded into a pressure extraction chamber equipped with an air inlet and a liquid outlet. The oil-containing animal and plant raw materials include oilseeds, oil-containing fruit pulp, oil-containing medicinal and edible plant tissues, and animal lipid tissues that can form a flowing oil phase at the processing temperature.

[0006] S2. Without adding a liquid extractant, the processing temperature is controlled to keep the raw material oil in a flowing state. Inert gas is introduced through the air inlet to raise the pressure extraction chamber to a negative pressure and maintain the pressure. The inert gas is preferably nitrogen or argon, more preferably nitrogen. The processing temperature is not higher than 35°C, and the condition for keeping the raw material oil in a flowing state is that no visible solid crystals are found at this temperature and the dynamic viscosity is not greater than 100 mPa·s.

[0007] S3. After the pressure holding period ends, close the air inlet passage to isolate the pressure-bearing extraction chamber from the inert gas source, open the pressure relief passage connected to the drain port, and close the pressure relief passage after the pressure-bearing extraction chamber is reduced to the retained negative pressure. The retained negative pressure is 40% to 65% of the pressure treatment negative pressure. Both the pressure treatment negative pressure and the retained negative pressure are gauge pressures. During the pressure reduction process, the oil containing fat-soluble active ingredients discharged from the raw material particles gathers towards the drain port side to form gas-containing oil.

[0008] S4. Pre-adjust the gauge pressure in the collection chamber to 4% to 8% of the negative pressure, then connect the pressure extraction chamber and the collection chamber for the first transfer; when the negative pressure difference between the two chambers drops to 0.10 MPa to 0.30 MPa, end the first transfer and disconnect the two chambers; with the pressure extraction chamber isolated from the inert gas source and the increase in gauge pressure in the pressure extraction chamber not exceeding 0.01 MPa, separately reduce the pressure in the collection chamber to 40% to 60% of the gauge pressure at the end of the first transfer, then connect the two chambers for the second transfer; when the negative pressure difference between the two chambers drops to 0.04 MPa to 0.08 MPa, end the second transfer and disconnect the two chambers.

[0009] S5. After the second transfer, the gauge pressure in the collection chamber is maintained within the range of ±0.005MPa of the negative pressure at the end of the second transfer for 60 to 180 seconds through negative pressure feedback. Then, the first stage of depressurization is performed to reduce the collection chamber to a degassing transition negative pressure higher than atmospheric pressure, and it is maintained within the range of ±0.005MPa for 60 to 300 seconds. Then, the pressure is reduced to atmospheric pressure for two to four intermittent periods, and the pressure is maintained within the range of ±0.005MPa between adjacent intermittent pressure reductions for 30 to 120 seconds. The second average depressurization rate of the collection chamber is 15% to 40% of the first average depressurization rate of the collection chamber. The degassed oil is centrifuged to obtain an oil phase containing fat-soluble active ingredients.

[0010] Furthermore, the negative pressure of the pressurization process is 2.0 MPa to 8.0 MPa, and the raw material particles are held under the negative pressure for 30 to 180 seconds.

[0011] Furthermore, the process of reducing the pressure in the pressure extraction chamber from the pressurized negative pressure to the retained negative pressure includes a first depressurization, an intermediate negative pressure maintenance, and a second depressurization. The first depressurization reduces the pressure in the pressure extraction chamber to the intermediate retained negative pressure, which is 70% to 85% of the pressurized negative pressure. After the gauge pressure in the pressure extraction chamber is maintained within the range of ±0.02 MPa of the intermediate retained negative pressure for 30 to 150 seconds through negative pressure feedback, the second depressurization reduces the pressure in the pressure extraction chamber from the intermediate retained negative pressure to the retained negative pressure.

[0012] Furthermore, the ratio of the negative pressure drop value of the first depressurization to the first depressurization time is used as the first depressurization average speed of the pressure-bearing extraction chamber, and the ratio of the negative pressure drop value of the second depressurization to the second depressurization time is used as the second depressurization average speed of the pressure-bearing extraction chamber. The second depressurization average speed of the pressure-bearing extraction chamber is 25% to 50% of the first depressurization average speed of the pressure-bearing extraction chamber.

[0013] Furthermore, after the pressure extraction chamber is reduced to a retained negative pressure, the raw material particles are kept for 30 to 180 seconds while the drain port and the collection chamber are kept separate. Then, the gas-containing oil collected on the drain port side is transferred to the collection chamber.

[0014] Furthermore, the gas-containing oil undergoes a first transfer and a second transfer in sequence; the gauge pressure of the collecting chamber before the first transfer is 4% to 8% of the retained negative pressure; the first transfer ends when the negative pressure difference between the two chambers drops to 0.10 MPa to 0.30 MPa; after the first transfer, the negative pressure of the collecting chamber is reduced separately. This pressure reduction process simultaneously pre-degasses the gas-containing oil that entered the collecting chamber during the first transfer and re-establishes the negative pressure difference required for the second transfer.

[0015] Furthermore, the second transfer ends when the negative pressure difference between the two chambers drops to 0.04 MPa to 0.08 MPa; at the end of the second transfer, the gauge pressure in the pressure extraction chamber is 0.10 MPa to 0.25 MPa, and the gauge pressure in the pressure extraction chamber is higher than the gauge pressure in the collection chamber; after the second transfer, the two chambers are isolated, and the negative pressure of the collection chamber at the end of the second transfer is maintained by feedback control of the negative pressure sensor of the collection chamber and the proportional regulating valve of the collection chamber.

[0016] Furthermore, the degassing transition negative pressure is 30% to 50% of the liquid collection negative pressure at the end of the second transfer; the first stage of pressure reduction and each intermittent pressure reduction are controlled based on real-time negative pressure data. After reaching the target negative pressure, a proportional regulating valve is used to intermittently exhaust gas to compensate for the negative pressure rebound caused by the continuous gas evolution of the gas-containing oil.

[0017] In this invention, limited pressure relief refers to the pressure in the extraction chamber being reduced from the negative pressure of the pressurized treatment to a retained negative pressure that is still higher than atmospheric pressure, and the pressure relief passage being closed after the retained negative pressure is reached; gas-containing oil refers to the mixture discharged from the raw material particles and carrying dissolved inert gases, dispersed bubbles, water, or a small amount of fine solids; degassed oil refers to the mixture to be centrifuged after the liquid collection chamber is reduced to atmospheric pressure and allowed to stand; the oil phase refers to the continuous phase separated from the emulsion layer, aqueous phase, and solid sediments after centrifugation; the final oil mass in the oil phase refers to the net mass of the oil after deducting water, volatiles, and insoluble impurities in the oil phase.

[0018] The beneficial effects of this invention are as follows: 1. This invention, after pressurization and pressure holding, partially depressurizes the pressure-bearing extraction chamber to retain negative pressure, taking into account the changes in the negative pressure of the raw material and the subsequent drainage force, so that the oil is collected and transferred to the drainage side before the pressure-bearing extraction chamber is completely depressurized. A segmented negative pressure treatment process is formed through the first depressurization, the intermediate negative pressure maintenance and the second depressurization, and an oil collection time is set after the retain negative pressure is reached, which is beneficial to the dispersion of oil in low oil content dense raw materials to form a transferable liquid.

[0019] 3. In this invention, the pressure extraction chamber is kept closed after the first transfer. The negative pressure difference is re-established by reducing the negative pressure of the collection chamber separately. The second transfer is completed without increasing the negative pressure on the raw material side. This is beneficial for discharging high-viscosity oil and residual oil in the raw material bed and drainage path.

[0020] 4. This invention implements a first-stage depressurization, a degassing transition negative pressure maintenance, and a second-stage intermittent depressurization after isolating the gas-containing oil from the raw material particles. This separates the gas evolution process of the gas-containing oil from the solid phase of the raw material, which helps to reduce the continuous disturbance of the oil-water system by foam and improve subsequent centrifugal stratification. At the same time, no liquid extractant is added during the extraction process, and the processing temperature is controlled in a low-temperature range where the raw oil has no visible crystals and can flow, thereby eliminating the need for liquid solvent addition and solvent recovery operations in the extraction stage. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the low-temperature pneumatic solventless extraction process of the present invention; Figure 2 This is a schematic diagram of the low-temperature pneumatic extraction device of the present invention; Figure 3 This is a schematic diagram of the gas-containing oil-liquid phased transfer and independent degassing process of the present invention; In the diagram: 1. Pressure-bearing extraction chamber; 2. Air inlet; 3. Liquid outlet; 4. Filter medium; 5. Liquid collection space on the drain side; 6. Pressure-bearing drain buffer chamber; 7. Pressure relief passage; 8. Oil transfer passage; 9. Liquid collection chamber; 10. Gas pressure regulating port; 11. Degassing port; 12. Liquid outlet. Detailed Implementation

[0022] The present invention will be further described below with reference to specific embodiments. The following embodiments are used to illustrate the technical solution of the present invention and its implementation under different raw material conditions, and are not intended to limit the scope of protection of the present invention. Unless otherwise stated, the negative pressures involved in the embodiments are gauge pressures, with atmospheric pressure corresponding to 0 MPa; data are expressed as the average value of three independent batches ± sample standard deviation, n=3.

[0023] like Figure 2As shown, the low-temperature pneumatic extraction device used in this embodiment includes a pressure-bearing extraction chamber, a pressure-bearing drain buffer chamber, a liquid collection chamber, an inert gas supply component, a temperature control component, a pressure relief component, a negative pressure detection component, and an oxygen concentration detection component. The pressure-bearing extraction chamber is a vertical cylindrical cavity with an effective volume of 30L, an inner diameter of 280mm, an effective height of 490mm, and a rated working gauge pressure of 10MPa. The pressure-bearing extraction chamber has an air inlet at the top and a drain outlet at the bottom. A removable filter medium is installed above the drain outlet, and a 0.80L liquid collection space is formed below the filter medium. The liquid collection space is connected to the pressure-bearing drain buffer chamber with an effective volume of 1.50L. The upper part of the pressure-bearing drain buffer chamber is connected to a pressure relief passage, and the lower part is connected to the liquid collection chamber via an oil transfer passage. The pressure relief passage is equipped with a pressure-bearing extraction chamber proportional control valve and a pressure-bearing extraction chamber defoaming component, and the trapped droplets return to the pressure-bearing drain buffer chamber.

[0024] The effective volume of the collection chamber is 60L, and the rated working gauge pressure is 6MPa. The top of the collection chamber has a gas pressure regulating port and a degassing port, while the bottom has a liquid outlet. The degassing port connects to the degassing passage of the collection chamber, which is sequentially equipped with a defoaming assembly and a proportional regulating valve. The oil trapped by the defoaming assembly returns to the collection chamber via a return flow path. Circulating temperature control jackets are installed around the pressure extraction chamber and the collection chamber. A raw material center temperature sensor is installed inside the pressure extraction chamber, a discharged liquid temperature sensor is installed at the discharge port, and a liquid temperature sensor is installed inside the collection chamber. The measurement accuracy of each temperature sensor is ±0.2℃. Figure 2 To simplify the structural diagram, the proportional control valve, negative pressure sensor, demister assembly, oxygen concentration detection assembly, and safety relief assembly are not shown individually.

[0025] The inert gas used is nitrogen with a purity of not less than 99.9%. The nitrogen enters the pressure extraction chamber via a pressure reducing valve, a gas booster pump, and a mass flow controller. The pressure extraction chamber is equipped with a high-pressure negative pressure sensor with a range of 0 MPa to 10 MPa and a resolution of 0.01 MPa; the liquid collection chamber is equipped with a low-pressure negative pressure sensor with a range of 0 MPa to 1 MPa and a resolution not exceeding 0.001 MPa. Negative pressure data is continuously recorded at a frequency of not less than 10 times per second. The proportional control valve is initially calibrated under no-load conditions, and closed-loop adjustment is performed using real-time negative pressure data during material loading, without directly replacing the actual pressure reduction time with the no-load calibration time. An oxygen concentration detection component is installed at the exhaust port of the pressure extraction chamber. Nitrogen purging continues until the oxygen volume fraction in the exhaust gas is not higher than 1.0%, and remains below this value for 10 consecutive seconds.

[0026] In this embodiment, the negative pressure of the pressurization treatment refers to the gauge pressure in the pressure-bearing extraction chamber when the raw material particles are subjected to nitrogen pressurization treatment; the intermediate negative pressure refers to the target gauge pressure in the pressure-bearing extraction chamber at the end of the first depressurization; the retained negative pressure refers to the gauge pressure retained in the pressure-bearing extraction chamber after the second depressurization; the negative pressure at the beginning of the second transfer and collection refers to the gauge pressure reached by reducing the negative pressure of the collection chamber alone after the first transfer ends and the two chambers are separated; the negative pressure at the end of the second transfer and collection refers to the gauge pressure in the collection chamber at the end of the second transfer; and the degassing transition negative pressure refers to the termination negative pressure of the first stage of depressurization and the starting negative pressure of the second stage of depressurization.

[0027] The operating sequence for each negative pressure stage is as follows: Figure 3 The average rate of the first depressurization in the pressure extraction chamber is calculated by dividing the negative pressure drop value of the first depressurization by the first depressurization time; the average rate of the second depressurization in the pressure extraction chamber is calculated by dividing the negative pressure drop value of the second depressurization by the second depressurization time. The average rate of the first depressurization in the collection chamber is calculated by dividing the negative pressure drop value from the end of the second transfer to the degassing transition negative pressure by the first depressurization time; the average rate of the second depressurization in the collection chamber is calculated by dividing the negative pressure drop value from the degassing transition negative pressure to atmospheric pressure by the total time of the second depressurization, which includes the time of each intermittent depressurization and the holding time between two adjacent intermittent depressurizations. The negative pressure drop value is the difference between the initial stable negative pressure and the final stable negative pressure of the corresponding stage. Stable negative pressure refers to the average negative pressure that fluctuates within 5 seconds without exceeding the specified negative pressure control deviation.

[0028] Moisture content of raw materials was determined using the constant weight method at 105℃; total oil content of low-moisture seed raw materials was determined using Soxhlet extraction; total oil content of high-moisture plant and animal tissues was determined using organic solvent extraction after acid hydrolysis. Oil samples from the same batch of raw materials were obtained by mechanical pressing or centrifugation at temperatures not exceeding the processing temperature, without the addition of organic solvents during the extraction process; after being kept at the target processing temperature for 10 minutes, oil samples were analyzed using a rotational viscometer over 50 seconds. -1 Dynamic viscosity was determined at the shear rate, and the presence of visible solid crystals was observed in a transparent sample tube. The gas-containing oil solutions obtained from the first and second transfers were thoroughly mixed after each transfer, and the total mass of the corresponding gas-containing oil solution was weighed, with at least three parallel samples taken. The samples were dehydrated with anhydrous sodium sulfate, extracted with n-hexane, and the oil mass was weighed to determine the oil mass fraction. The converted oil mass from the staged transfers was calculated as the product of the total mass of the corresponding gas-containing oil solution and the oil mass fraction of the sample.

[0029] The oil phase recovery rate is calculated as the ratio of the net mass of oil in the final oil phase to the total mass of the raw material oil; the contribution rate of the second transfer is calculated as the ratio of the equivalent mass of the second transferred oil to the sum of the equivalent masses of the first and second transferred oils; the emulsion layer ratio is calculated as the ratio of the mass of the emulsion layer after centrifugation to the mass of the degassed oil before centrifugation; the relative content retention rate of active ingredients is calculated as the ratio of the mass concentration of the target lipophilic active ingredient in the final oil phase to the mass concentration of the same target lipophilic active ingredient in the same batch of raw material oil. The residual gas volume is determined by the closed quantitative reduced pressure escaping method: 100g of oil phase is placed in a closed container at 25℃ and maintained at an absolute negative pressure of 20kPa for 10 minutes, allowing the escaping gas to pass sequentially through a 5℃ condensation section and an anhydrous drying section before being collected by a calibrated gas-tight measuring tube. The escaping gas volume of the blank container is subtracted and converted into the standard state non-condensable escaping gas volume per kilogram of oil.

[0030] Each embodiment and comparative example underwent three independent batch processing. Each batch underwent a complete re-loading of raw materials, nitrogen purging, pressurization, and transfer, depressurization, and centrifugation operations adapted to the corresponding embodiment or comparative example. Unless otherwise stated, after the liquid collection chamber was reduced to atmospheric pressure, it was allowed to stand for 5 minutes before the degassed oil was dispensed into sealed centrifuge bottles. Centrifugation time refers to the time to reach a constant speed after the set relative centrifugal force is achieved; the total centrifugation cycle time also includes acceleration and deceleration times.

[0031] Example 1

[0032] Shelled peony kernels from the same origin, harvest season, and stored for no more than six months were selected. Shell fragments, moldy particles, and visible foreign matter were removed. Three independent batches were established, each with a net weight of 10.00 kg. The moisture content of the three batches was 5.7%, 5.9%, and 5.8%, respectively; the total oil content was 28.4%, 28.8%, and 28.6%, respectively; the corresponding total oil weights were 2.84 kg, 2.88 kg, and 2.86 kg, respectively; and the total tocopherol content in the oil was 476 mg / kg, 469 mg / kg, and 481 mg / kg, respectively.

[0033] Peony seeds were equilibrated at 20℃ for 4 hours, then coarsely crushed using a blade-type coarse crusher at 850 rpm. 2.0 kg of peony seeds were added at a time, with each crushing cycle lasting 25 seconds. The highest temperature of the raw material during coarse crushing was 24.6℃. After coarse crushing, the raw materials were sieved using 0.8 mm, 1.5 mm, 3.5 mm, and 5.0 mm screens. The proportion of raw material particles smaller than 0.8 mm was 4.1% to 4.6% by mass; particles between 0.8 mm and 1.5 mm accounted for 16.4% to 17.2% by mass; particles between 1.5 mm and 3.5 mm accounted for 62.0% to 63.3% by mass; and particles between 3.5 mm and 5.0 mm accounted for 14.6% to 15.5% by mass. Particles larger than 5.0 mm were returned to the coarse crusher for further coarse crushing. The raw material particles with a particle size of no more than 5.0 mm were mixed evenly, and the loose bulk density of the three batches of raw material particles were 0.476 kg / L, 0.483 kg / L and 0.480 kg / L, respectively.

[0034] A filter with an 80μm pore size, a 3mm thickness, and an effective filtration area of ​​0.061m² is installed at the bottom of the pressure extraction chamber. 2 The stainless steel sintered filter media was used. Each batch of 10.00 kg of raw material particles was loaded into the pressure extraction chamber in four portions. After each loading, the material surface was leveled without mechanical compaction. The loading volumes of the three batches of raw material particles were 21.01 L, 20.70 L, and 20.83 L, respectively; the loading heights were 341 mm, 336 mm, and 338 mm, respectively; and the free gas phase volumes above the raw material bed were 8.19 L, 8.50 L, and 8.37 L, respectively.

[0035] The jacket temperature of the pressure extraction chamber and the collection chamber was set to 18℃ to stabilize the center temperature of the raw material particles at 18℃±1℃. Raw material oil samples were obtained from the same batch of peony seed kernels. The raw material oil showed no visible crystals at 18℃, and its dynamic viscosity ranged from 72 mPa·s to 82 mPa·s. 20 mL of the raw material oil was placed above an 80 μm filter medium. Under a negative pressure difference of 0.05 MPa, three parallel samples passed through the filter medium within 43 s, 47 s, and 50 s, respectively, confirming that the raw material oil could maintain flow under 18℃ conditions.

[0036] Nitrogen gas is introduced into the pressure extraction chamber to bring it to 0.10 MPa. This pressure is maintained for 15 seconds, then the pressure is released to atmospheric pressure. This process is repeated three times. After the third release, nitrogen gas is introduced at a low flow rate until the oxygen volume fraction at the exhaust port is no higher than 1.0% and remains within this range for 10 consecutive seconds. Then, the pressure relief passage and oil transfer passage are closed, and nitrogen is introduced at a flow rate of 0.42 Nm. 3 / min to 0.47Nm 3The nitrogen flow rate was increased to 3.00 MPa in the pressure extraction chambers of the three batches within 42, 46, and 44 seconds, respectively. The negative pressure for the pressurization process of the three batches was 3.00 MPa. After reaching and stabilizing the negative pressure for 5 seconds, the gas inlet was closed, and the pressure was maintained for 120 seconds. During the pressure maintenance period, the gauge pressure in the pressure extraction chambers was maintained between 2.97 MPa and 3.02 MPa, and the center temperature of the raw material particles was maintained between 18.2℃ and 18.8℃.

[0037] After the pressure holding period ends, the pressure relief passage is opened, and the pressure in the extraction chamber is reduced from 3.00 MPa to 2.40 MPa within 8 seconds. 2.40 MPa is defined as the intermediate negative pressure, which is 80% of the negative pressure applied during the pressurization process. Once the intermediate negative pressure is reached, the pressure relief passage is closed, and the raw material particles are held at 2.38 MPa to 2.42 MPa for 90 seconds. After the intermediate negative pressure is maintained, the pressure relief passage is opened again, and the pressure in the extraction chamber is reduced from 2.40 MPa to 1.65 MPa within 25 seconds. 1.65 MPa is defined as the retention negative pressure, which is 55% of the negative pressure applied during the pressurization process. Once the retention negative pressure is reached, the pressure relief passage is closed.

[0038] The first pressure drop during depressurization was 0.60 MPa, and the first depressurization time was 8 s. The calculated average velocity of the first depressurization in the pressure-bearing extraction chamber was 0.075 MPa / s. The second pressure drop during depressurization was 0.75 MPa, and the second depressurization time was 25 s. The calculated average velocity of the second depressurization in the pressure-bearing extraction chamber was 0.030 MPa / s. The average velocity of the second depressurization in the pressure-bearing extraction chamber was 40% of the average velocity of the first depressurization in the pressure-bearing extraction chamber.

[0039] After the pressure extraction chamber reaches the negative pressure, the pressure relief passage and oil transfer passage are kept closed. The gauge pressure in the pressure extraction chamber is maintained within the range of 1.65MPa±0.02MPa for 90 seconds through negative pressure feedback. During the maintenance process, the liquid discharged from the raw material particles enters the liquid collection space on the discharge side and the pressure discharge buffer chamber through the filter medium. The three batches are collected in the liquid collection space on the discharge side and the pressure discharge buffer chamber to obtain 0.40kg, 0.43kg and 0.42kg of gas-containing oil, respectively.

[0040] During the period of maintaining negative pressure, the gauge pressure in the empty collection chamber was adjusted to 0.10 MPa, approximately 6.1% of the maintained negative pressure. Then, the gas pressure regulating port was closed and the oil transfer passage was opened, connecting the two chambers. The durations of the first transfer for the three batches were 82 seconds, 87 seconds, and 85 seconds, respectively. At the end of the first transfer, the gauge pressures in the pressure extraction chamber were 0.48 MPa, 0.49 MPa, and 0.48 MPa, respectively, and the gauge pressures in the collection chamber were 0.27 MPa, 0.28 MPa, and 0.27 MPa, respectively, with a negative pressure difference of 0.21 MPa between the two chambers. After closing the oil transfer passage, the mass of gas-containing oil obtained from the first transfer for the three batches was 1.18 kg, 1.23 kg, and 1.21 kg, respectively. Using the aforementioned sampling conversion method, the converted mass of the oil from the first transfer was 0.960 kg, 0.990 kg, and 0.980 kg, respectively.

[0041] After the first transfer, the gauge pressure in the three batches of the collecting chamber was reduced from 0.27 MPa, 0.28 MPa, and 0.27 MPa to 0.135 MPa, 0.140 MPa, and 0.135 MPa, respectively, through the degassing port at the top of the collecting chamber. The resulting initial negative pressure for the second transfer was 50% of the gauge pressure in the collecting chamber at the end of the first transfer. This separate depressurization process also pre-degassed the gas-containing oil entering the collecting chamber during the first transfer. The oil mist discharged during the separate depressurization process in the collecting chamber was 4.8 g, 5.2 g, and 5.0 g, respectively, which was intercepted by the defoaming component and returned to the collecting chamber via the return flow path.

[0042] The oil transfer pathway was reopened for a second transfer. The duration of the second transfer for the three batches was 91 seconds, 96 seconds, and 94 seconds, respectively. At the end of the second transfer, the gauge pressure in the pressure extraction chamber was 0.22 MPa, 0.24 MPa, and 0.23 MPa, respectively, and the gauge pressure in the collection chamber was 0.16 MPa, 0.18 MPa, and 0.17 MPa, respectively. The negative pressure difference between the two chambers was 0.06 MPa, which meets the termination condition of the second transfer at 0.04 MPa to 0.08 MPa. The mass of gas-containing oil obtained from the second transfer for the three batches was 0.31 kg, 0.34 kg, and 0.33 kg, respectively. According to the aforementioned sampling conversion method, the equivalent mass of the oil from the second transfer was 0.245 kg, 0.255 kg, and 0.252 kg, respectively, with the contribution rates of the second transfer being 20.3%, 20.5%, and 20.5%, respectively.

[0043] After the second transfer, the oil transfer passage was closed. Feedback control from the collecting chamber negative pressure sensor and the collecting chamber proportional control valve maintained the gauge pressure in the collecting chambers of the three batches within the ranges of 0.16MPa±0.005MPa, 0.18MPa±0.005MPa, and 0.17MPa±0.005MPa, respectively, for 120 seconds. Then, the first stage of depressurization was performed, reducing the gauge pressure in the collecting chambers of the three batches to 0.066MPa, 0.075MPa, and 0.070MPa, respectively, which are 41.3%, 41.7%, and 41.2% of the negative pressure at the end of the second transfer, respectively. This negative pressure was then used as the degassing transition negative pressure.

[0044] Taking the third batch as an example, the first stage of negative pressure drop is 0.10 MPa, the first stage of pressure drop time is 10 seconds, and the first average pressure drop rate of the collection chamber is 0.010 MPa / s. After reaching the degassing transition negative pressure, the gauge pressure in the collection chamber is maintained within the range of 0.070 MPa ± 0.005 MPa for 120 seconds through negative pressure feedback. In the second stage, the first intermittent pressure drop reduces the pressure in the collection chamber from 0.070 MPa to 0.035 MPa within 3 seconds, and maintains it within the range of 0.035 MPa ± 0.005 MPa for 29 seconds. The second intermittent pressure drop reduces the pressure to atmospheric pressure within 3 seconds. The total pressure drop time of the second stage is 35 seconds, and the second average pressure drop rate of the collection chamber is 0.0020 MPa / s, which is 20% of the first average pressure drop rate of the collection chamber.

[0045] After the collection chamber was lowered to atmospheric pressure, the mixture was allowed to stand for 5 minutes. The degassed oil was then dispensed into sealed 500mL centrifuge bottles, with 400mL of liquid in each bottle. The bottles were centrifuged at a constant speed for 10 minutes at 18℃ and a relative centrifugal force of 4000g, with an acceleration time of 60 seconds and a natural deceleration time of 90 seconds. After centrifugation, the upper oil phase, emulsion layer, and aqueous phase were collected sequentially, and the bottom solid sediment was weighed separately. The net oil mass in the final oil phase of the three batches was 1.179kg, 1.210kg, and 1.201kg, respectively, with corresponding oil phase recovery rates of 41.5%, 42.0%, and 42.0%. The water content in the oil phase was 0.18%, 0.20%, and 0.19%, respectively; the insoluble impurity content was 0.13%, 0.15%, and 0.14%, respectively; and the relative content retention rate of the total tocopherol active ingredient was 90.2%, 91.1%, and 90.7%, respectively.

[0046] Example 2

[0047] Avocados of uniform ripeness and with a flesh firmness of 18N to 23N were selected. After peeling and pitting, the flesh was obtained in three independent batches, each weighing 8.00 kg. The moisture content of the three batches was 66.8%, 67.5%, and 68.1%, respectively; the total oil content was 17.5%, 18.2%, and 18.1%, respectively; and the corresponding total oil weights were 1.400 kg, 1.456 kg, and 1.448 kg. The total carotenoid content in the three batches was 38.6 mg / kg, 40.1 mg / kg, and 39.4 mg / kg, respectively.

[0048] Avocado pulp was cut into irregular granules with sides ranging from 4mm to 8mm. High-speed shearing was not used during the cutting process, and the maximum temperature of the raw material was controlled below 26℃. The loose bulk density of the raw material granules in the three batches ranged from 0.72kg / L to 0.74kg / L, with a filling volume of 10.81L to 11.11L and a filling height of 176mm to 180mm per batch. A sintered stainless steel filter medium with a pore size of 150μm and a thickness of 4mm was installed inside the pressurized extraction chamber, and a pressure-resistant support mesh with a pore size of 500μm was placed above the filter medium.

[0049] The center temperature of the raw material particles was controlled at 24℃±1℃. The avocado oil obtained using the aforementioned method showed no visible solid crystals at 24℃, and its dynamic viscosity ranged from 68 mPa·s to 82 mPa·s. After nitrogen purging according to the aforementioned oxygen concentration termination conditions, the pressure extraction chamber was raised to 2.40 MPa within 39 to 44 seconds and maintained at 2.40 MPa for 150 seconds.

[0050] After the pressure holding period, the pressure in the extraction chamber is reduced from 2.40 MPa to 1.80 MPa within 9 seconds. This 1.80 MPa is defined as the intermediate negative pressure, which is 75% of the negative pressure applied during the pressurization process. This intermediate negative pressure is maintained for 120 seconds. Subsequently, the pressure in the extraction chamber is reduced from 1.80 MPa to 1.08 MPa within 27 seconds. This 1.08 MPa is defined as the retention negative pressure, which is 45% of the negative pressure applied during the pressurization process. In this embodiment, the average first depressurization rate of the extraction chamber is 0.0667 MPa / s, and the average second depressurization rate is 0.0267 MPa / s. The average second depressurization rate is 40% of the average first depressurization rate.

[0051] After achieving the required negative pressure, the gauge pressure in the pressure extraction chamber is maintained within the range of 1.08 MPa ± 0.02 MPa for 150 seconds via negative pressure feedback. The collection chamber is pre-adjusted to 0.08 MPa, approximately 7.4% of the required negative pressure, before the first transfer. At the end of the first transfer, the gauge pressure in the pressure extraction chamber is 0.42 MPa to 0.44 MPa, and the gauge pressure in the collection chamber is 0.27 MPa to 0.29 MPa, with a negative pressure difference of 0.14 MPa to 0.16 MPa between the two chambers. The converted mass of the oil in the first transfer for the three batches is 0.430 kg, 0.460 kg, and 0.450 kg, respectively.

[0052] The gauge pressure in the collection chambers of the three batches was reduced to 0.135 MPa, 0.145 MPa, and 0.140 MPa, respectively, as the starting negative pressure for the second transfer, all representing 50% of the gauge pressure at the end of the first transfer. At the end of the second transfer, the gauge pressures in the pressure extraction chambers were 0.21 MPa, 0.23 MPa, and 0.22 MPa, respectively, and the gauge pressures in the collection chambers were 0.15 MPa, 0.17 MPa, and 0.16 MPa, respectively, with a negative pressure difference of 0.06 MPa between the two chambers. The converted mass of the oil in the second transfer for the three batches was 0.120 kg, 0.130 kg, and 0.128 kg, respectively, with contribution rates of 21.8%, 22.0%, and 22.1%, respectively.

[0053] After the second transfer, negative pressure feedback was used to maintain the gas-containing oil within the range of ±0.005 MPa of the corresponding negative pressure at the end of the second transfer for 150 seconds. Subsequently, the gauge pressure in the collection chambers of the three batches was reduced from 0.15 MPa, 0.17 MPa, and 0.16 MPa to 0.070 MPa, respectively. The first stage of pressure reduction time was 12 seconds for each batch, and the first average pressure reduction rate in the collection chambers was 0.00667 MPa / s, 0.00833 MPa / s, and 0.00750 MPa / s, respectively. The degassing transition negative pressures were 46.7%, 41.2%, and 43.8% of the negative pressure at the end of the second transfer, respectively. After maintaining the pressure within the range of 0.070 MPa ± 0.005 MPa for 180 seconds, the second stage of depressurization is performed. The first intermittent depressurization reduces the pressure to 0.035 MPa within 5 seconds, and maintains it within the range of 0.035 MPa ± 0.005 MPa for 30 seconds. The second intermittent depressurization reduces the pressure to atmospheric pressure within 5 seconds. The second average depressurization rate of the liquid collecting chamber is 0.00175 MPa / s, which is 26.2%, 21.0%, and 23.3% of the first average depressurization rate of the corresponding liquid collecting chamber.

[0054] The degassed oil was centrifuged at a constant speed for 15 minutes at 20°C and a relative centrifugal force of 5000g. The net weights of the oil in the final oil phase of the three batches were 0.524 kg, 0.568 kg, and 0.557 kg, respectively, with corresponding oil phase recovery rates of 37.4%, 39.0%, and 38.5%; emulsion layer ratios were 13.1%, 14.4%, and 13.8%, respectively; oil phase moisture content ranged from 0.31% to 0.42%; and the relative content retention rates of carotenoid active ingredients were 86.2%, 88.1%, and 87.4%, respectively.

[0055] Example 3

[0056] Fresh, mature coconut meat was selected, the brown husk was removed, and the meat was chopped. Three independent batches were prepared, each weighing 8.00 kg. The moisture content of the three batches of coconut meat was 44.7%, 46.3%, and 45.4%, respectively, and the total oil content was 30.6%, 31.8%, and 31.2%, respectively. The corresponding total oil weights of the raw materials were 2.448 kg, 2.544 kg, and 2.496 kg, respectively.

[0057] Coconut meat was cut into 2mm to 5mm particles. The loose bulk density of the particles in three batches ranged from 0.65kg / L to 0.67kg / L, the packing volume ranged from 11.94L to 12.31L, and the packing height ranged from 194mm to 200mm. A sintered stainless steel filter medium with a pore size of 100μm and a thickness of 4mm was installed in the pressurized extraction chamber. The processing temperature was controlled at 28℃±1℃. It was found that no visible solid crystals were observed in the coconut oil of the same batch at 28℃, and the dynamic viscosity ranged from 42mPa·s to 56mPa·s.

[0058] After nitrogen purging is completed according to the aforementioned oxygen concentration termination conditions, the pressure in the extraction chamber is raised to 4.00 MPa within 58 to 65 seconds and maintained at 4.00 MPa for 180 seconds. After the pressure holding period, the pressure in the extraction chamber is lowered to 3.20 MPa within 10 seconds and maintained within the range of 3.20 MPa ± 0.02 MPa for 150 seconds; subsequently, it is lowered to 2.00 MPa within 30 seconds. The average first depressurization rate of the extraction chamber is 0.080 MPa / s, and the average second depressurization rate is 0.040 MPa / s, with a ratio of 50%.

[0059] After reaching a retention negative pressure of 2.00 MPa, the negative pressure feedback is maintained for 150 seconds. The collection chamber is then pre-adjusted to 0.15 MPa, approximately 7.5% of the retention negative pressure, before the first transfer. At the end of the first transfer, the gauge pressure in the pressure extraction chamber is 0.53 MPa to 0.55 MPa, and the gauge pressure in the collection chamber is 0.29 MPa to 0.31 MPa, with a negative pressure difference of 0.23 MPa to 0.25 MPa between the two chambers. The converted mass of the oil from the first transfer for the three batches is 0.880 kg, 0.920 kg, and 0.900 kg, respectively.

[0060] The gauge pressure in the collection chamber was reduced to 0.145 MPa, 0.155 MPa, and 0.150 MPa, respectively, as the starting negative pressure for the second transfer, all approximately 50% of the gauge pressure at the end of the first transfer. At the end of the second transfer, the gauge pressures in the pressure extraction chamber were 0.24 MPa, 0.25 MPa, and 0.25 MPa, respectively, and the gauge pressures in the collection chamber were 0.17 MPa, 0.18 MPa, and 0.18 MPa, respectively, with a negative pressure difference of 0.07 MPa between the two chambers. The converted masses of the oil in the three batches after the second transfer were 0.300 kg, 0.320 kg, and 0.310 kg, respectively, with contribution rates of 25.4%, 25.8%, and 25.6%, respectively.

[0061] After the second transfer, negative pressure feedback was used to maintain the gas-containing oil within the range of ±0.005 MPa of the corresponding negative pressure at the end of the second transfer for 180 seconds. Subsequently, the gauge pressure in the collection chambers of the three batches was reduced from 0.17 MPa, 0.18 MPa, and 0.18 MPa to 0.080 MPa, respectively. The first stage of pressure reduction time was 12 seconds for each batch, and the first average pressure reduction rate in the collection chambers was 0.00750 MPa / s, 0.00833 MPa / s, and 0.00833 MPa / s, respectively. The degassing transition negative pressures were 47.1%, 44.4%, and 44.4% of the negative pressure at the end of the second transfer, respectively. After maintaining the pressure within the range of 0.080 MPa ± 0.005 MPa for 180 seconds, the second stage of depressurization is performed. The first intermittent depressurization reduces the pressure to 0.040 MPa within 5 seconds, and maintains it within the range of 0.040 MPa ± 0.005 MPa for 35 seconds. The second intermittent depressurization reduces the pressure to atmospheric pressure within 5 seconds. The second average depressurization rate of the liquid collecting chamber is 0.00178 MPa / s, which is 23.7%, 21.3%, and 21.3% of the first average depressurization rate of the corresponding liquid collecting chamber, respectively.

[0062] The degassed oil was centrifuged at a constant speed of 12 minutes at 28℃ and a relative centrifugal force of 4500g. The net weights of the oil in the final oil phase of the three batches were 1.129 kg, 1.196 kg, and 1.158 kg, respectively, with corresponding oil phase recovery rates of 46.1%, 47.0%, and 46.4%; the proportions of the emulsion layer were 7.0%, 7.8%, and 7.4%, respectively; and the relative content retention rates of the active phytosterols were 88.7%, 90.3%, and 89.5%, respectively.

[0063] Example 4

[0064] Grape seeds, separated, cleaned, and dried after winemaking, were selected and divided into three independent batches, each weighing 12.00 kg. The moisture content of the grape seeds in the three batches was 6.9%, 7.4%, and 7.1%, respectively, and the total oil content was 12.7%, 13.4%, and 13.1%, respectively. The corresponding total oil content of the raw materials was 1.524 kg, 1.608 kg, and 1.572 kg, respectively.

[0065] Grape seeds were crushed to 0.8mm to 3.0mm using a double-roll crusher, with the proportion of fine powder (particle size less than 0.5mm) controlled to be below 5%. The loose bulk density of the three batches of coarsely crushed grape seeds ranged from 0.57kg / L to 0.59kg / L, the packing volume ranged from 20.34L to 21.05L, and the packing height ranged from 330mm to 342mm. The processing temperature was controlled at 20℃±1℃, and a sintered stainless steel filter medium with a pore size of 60μm was installed in the pressure extraction chamber.

[0066] After nitrogen purging according to the aforementioned oxygen concentration termination conditions, the pressure in the extraction chamber is raised to 6.00 MPa within 85 to 94 seconds and maintained at 6.00 MPa for 180 seconds. After the pressure holding period, the pressure in the extraction chamber is lowered to 4.50 MPa within 15 seconds and maintained within the range of 4.50 MPa ± 0.02 MPa for 150 seconds; subsequently, it is lowered to 2.70 MPa within 36 seconds. The average first depressurization rate of the extraction chamber is 0.100 MPa / s, and the average second depressurization rate is 0.050 MPa / s, with a ratio of 50%.

[0067] After reaching a retention negative pressure of 2.70 MPa, the negative pressure feedback was maintained for 180 seconds. The collection chamber was then pre-adjusted to 0.12 MPa, approximately 4.4% of the retention negative pressure, before the first transfer. At the end of the first transfer, the gauge pressure in the pressure extraction chamber was 0.49 MPa to 0.51 MPa, and the gauge pressure in the collection chamber was 0.27 MPa to 0.29 MPa, with a negative pressure difference of 0.21 MPa to 0.23 MPa between the two chambers. The converted mass of the oil from the first transfer for the three batches was 0.320 kg, 0.340 kg, and 0.330 kg, respectively.

[0068] The gauge pressure in the collection chamber was reduced to 0.135 MPa, 0.145 MPa, and 0.140 MPa, respectively, as the starting negative pressure for the second transfer, all approximately 50% of the gauge pressure at the end of the first transfer. At the end of the second transfer, the gauge pressures in the pressure extraction chamber were 0.22 MPa, 0.24 MPa, and 0.23 MPa, respectively, and the gauge pressures in the collection chamber were 0.16 MPa, 0.18 MPa, and 0.17 MPa, respectively, with a negative pressure difference of 0.06 MPa between the two chambers. The converted masses of the oil in the second transfer for the three batches were 0.120 kg, 0.130 kg, and 0.125 kg, respectively, with contribution rates of 27.3%, 27.7%, and 27.5%, respectively.

[0069] After the second transfer, negative pressure feedback was used to maintain the gas-containing oil within the range of ±0.005 MPa of the corresponding negative pressure at the end of the second transfer for 180 seconds. Subsequently, the gauge pressure in the collection chambers of the three batches was reduced from 0.16 MPa, 0.18 MPa, and 0.17 MPa to 0.070 MPa, respectively. The first stage of pressure reduction time was 12 seconds for each batch, and the first average pressure reduction rate in the collection chambers was 0.00750 MPa / s, 0.00917 MPa / s, and 0.00833 MPa / s, respectively. The degassing transition negative pressures were 43.8%, 38.9%, and 41.2% of the negative pressure at the end of the second transfer, respectively. After maintaining the pressure within the range of 0.070 MPa ± 0.005 MPa for 240 seconds, the second stage of depressurization is performed. The first intermittent depressurization reduces the pressure to 0.035 MPa within 6 seconds, and maintains the pressure within the range of 0.035 MPa ± 0.005 MPa for 30 seconds. The second intermittent depressurization reduces the pressure to atmospheric pressure within 6 seconds. The second average depressurization rate of the liquid collecting chamber is 0.00167 MPa / s, which is 22.2%, 18.2%, and 20.0% of the first average depressurization rate of the corresponding liquid collecting chamber.

[0070] The degassed oil was centrifuged at a constant speed of 10 minutes at 20°C and a relative centrifugal force of 4500g. The net weights of the oil in the final oil phase of the three batches were 0.430 kg, 0.468 kg, and 0.453 kg, respectively, with corresponding oil phase recovery rates of 28.2%, 29.1%, and 28.8%; the proportions of the emulsion layer were 4.6%, 5.2%, and 4.9%, respectively; and the relative content retention rates of the active ingredient in total tocopherols were 88.8%, 90.7%, and 90.0%, respectively.

[0071] Example 5

[0072] Abdominal fatty tissue generated during the processing of the same batch of refrigerated salmon was selected. Fish bones, scales, and visible blood clots were removed, and three independent batches were established, each weighing 10.00 kg. The moisture content of the three batches was 56.9%, 59.1%, and 58.0%, respectively; the total fat content was 23.8%, 25.2%, and 24.5%, respectively, corresponding to total fat masses of 2.38 kg, 2.52 kg, and 2.45 kg; and the protein content ranged from 13.7% to 15.4%.

[0073] The lipid-containing tissue was cut into particles with a side length of 5 mm to 10 mm, and the raw material temperature was maintained below 12℃ during the cutting process. The loose bulk density of the three batches of raw material particles ranged from 0.81 kg / L to 0.83 kg / L, the packing volume ranged from 12.05 L to 12.35 L, and the packing height ranged from 196 mm to 201 mm. A sintered stainless steel filter medium with a pore size of 200 μm and a thickness of 4 mm was installed in the pressure extraction chamber, and a pressure-resistant support mesh with a pore size of 800 μm was placed above the filter medium.

[0074] The temperature at the center of the raw material particles was controlled at 16℃±1℃ using a circulating temperature control jacket. The salmon fat obtained using the aforementioned method showed no visible solid crystals at 16℃, and its dynamic viscosity was 70 mPa·s to 90 mPa·s. After nitrogen purging according to the aforementioned oxygen concentration termination conditions, the pressure extraction chamber was raised to 2.20 MPa within 35 to 40 seconds and maintained at 2.20 MPa for 90 seconds.

[0075] After the pressure holding period, the pressure in the extraction chamber is reduced from 2.20 MPa to 1.65 MPa within 10 seconds. This 1.65 MPa is designated as the intermediate negative pressure, which is 75% of the negative pressure applied during the pressurization process. This intermediate negative pressure is maintained for 60 seconds. Subsequently, the pressure in the extraction chamber is reduced from 1.65 MPa to 1.21 MPa within 20 seconds. This 1.21 MPa is designated as the retention negative pressure, which is 55% of the negative pressure applied during the pressurization process. In this embodiment, the average first depressurization rate of the extraction chamber is 0.055 MPa / s, and the average second depressurization rate is 0.022 MPa / s, with a ratio of 40%.

[0076] After reaching a retention negative pressure of 1.21 MPa, the negative pressure feedback was maintained for 120 seconds. The collection chamber was then pre-adjusted to 0.07 MPa, approximately 5.8% of the retention negative pressure, before the first transfer. At the end of the first transfer, the gauge pressure in the pressure extraction chamber was 0.39 MPa to 0.41 MPa, and the gauge pressure in the collection chamber was 0.21 MPa to 0.23 MPa, with a negative pressure difference of 0.17 MPa to 0.19 MPa between the two chambers. The converted mass of the oil from the first transfer for the three batches was 0.780 kg, 0.820 kg, and 0.800 kg, respectively.

[0077] The gauge pressure in the collection chamber was reduced to 0.105 MPa, 0.115 MPa, and 0.110 MPa, respectively, as the starting negative pressure for the second transfer, all approximately 50% of the gauge pressure at the end of the first transfer. At the end of the second transfer, the gauge pressures in the pressure extraction chamber were 0.19 MPa, 0.21 MPa, and 0.20 MPa, respectively, and the gauge pressures in the collection chamber were 0.13 MPa, 0.15 MPa, and 0.14 MPa, respectively, with a negative pressure difference of 0.06 MPa between the two chambers. The converted masses of the oil in the three batches after the second transfer were 0.270 kg, 0.290 kg, and 0.280 kg, respectively, with contribution rates of 25.7%, 26.1%, and 25.9%, respectively.

[0078] After the second transfer, negative pressure feedback was used to maintain the gas-containing oil within the range of ±0.005 MPa of the corresponding negative pressure at the end of the second transfer for 120 seconds. Subsequently, the gauge pressure in the collection chambers of the three batches was reduced from 0.13 MPa, 0.15 MPa, and 0.14 MPa to 0.060 MPa, respectively. The first stage of pressure reduction time was 10 seconds for each batch, and the first average pressure reduction rate in the collection chambers was 0.0070 MPa / s, 0.0090 MPa / s, and 0.0080 MPa / s, respectively. The degassing transition negative pressures were 46.2%, 40.0%, and 42.9% of the negative pressure at the end of the second transfer, respectively. After maintaining the pressure within the range of 0.060 MPa ± 0.005 MPa for 180 seconds, the second stage of depressurization is performed. The first intermittent depressurization reduces the pressure to 0.030 MPa within 2 seconds, and maintains it within the range of 0.030 MPa ± 0.005 MPa for 30 seconds. The second intermittent depressurization reduces the pressure to atmospheric pressure within 2 seconds. The second average depressurization rate of the liquid collecting chamber is 0.00176 MPa / s, which is 25.2%, 19.6%, and 22.0% of the first average depressurization rate of the corresponding liquid collecting chamber.

[0079] The degassed oil was centrifuged at a constant speed of 18 minutes at 16℃ and a relative centrifugal force of 6000g. After centrifugation, an upper fish oil phase, a middle emulsion layer, a lower aqueous phase, and a bottom protein deposit were formed. The net oil mass in the final oil phase of the three batches was 1.009 kg, 1.086 kg, and 1.049 kg, respectively, with corresponding oil phase recovery rates of 42.4%, 43.1%, and 42.8%. The proportions of the emulsion layer were 14.2%, 15.5%, and 15.1%, respectively. The relative content retention rates of the active ingredients in the total eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were 87.4%, 89.6%, and 88.7%, respectively.

[0080] Comparative Example 1 The same batch of peony seeds, filling weight, processing temperature, nitrogen purging method, negative pressure during pressurization, and holding time as in Example 1 were used. After the holding time was completed, the pressure in the extraction chamber was continuously reduced from 3.00 MPa to atmospheric pressure. Once atmospheric pressure was reached, 0.05 MPa of nitrogen was introduced into the extraction chamber to assist in liquid drainage. The drained liquid was separated using the same centrifugation conditions as in Example 1. This comparative example did not include intermediate negative pressure maintenance, pressurized transfer under negative pressure, or a second transfer.

[0081] Comparative Example 2 The same batch of avocado pulp as in Example 2 was used, and the same pressurization, limited depressurization, negative pressure maintenance, first transfer, and second transfer processes were employed. After the second transfer, the liquid collection chamber was continuously reduced from the negative pressure at the end of the second transfer to atmospheric pressure. The total continuous depressurization time was set to 232 seconds, the same as the total time for the first stage of depressurization, the degassing transition negative pressure maintenance, and the second stage of depressurization in Example 2. No independent maintenance or intermittent depressurization under the degassing transition negative pressure was implemented during the continuous depressurization process.

[0082] Comparative Example 3 The same batch of coconut meat as in Example 3 was used, and the same processing temperature, nitrogen purging, pressurization, limited depressurization, negative pressure maintenance, and first transfer process were employed. After the first transfer, the negative pressure in the collection chamber was not reduced separately, and no second transfer was performed. The gas-containing oil liquid obtained from the first transfer was directly processed according to the two-stage depressurization and centrifugation conditions of Example 3.

[0083] Comparative Example 4 The same batch of grape seeds as in Example 4 were used, and the same coarse crushing conditions, filling conditions, pressurization treatment, intermediate negative pressure maintenance, and limited pressure relief conditions were applied. Once the pressurized extraction chamber reached the retained negative pressure, it was immediately connected to the collection chamber. The 180-second holding period under retained negative pressure was not included. Subsequent first transfer, second transfer, two-stage depressurization, and centrifugation conditions were the same as in Example 4.

[0084] Comparative Example 5 The same batch of fatty abdominal tissue from salmon as in Example 5 was used, and the same pressurization treatment, limited depressurization, negative pressure maintenance, first transfer, second transfer, first stage depressurization, and degassing transition negative pressure maintenance process as in Example 5 were employed. The second stage depressurization, from the degassing transition negative pressure to atmospheric pressure, was carried out using a continuous depressurization method, and the total continuous depressurization time was the same as the total depressurization time of the second stage in Example 5.

[0085] Comparative Example 6 The same batch of peony seeds, filling weight, processing temperature, pressurization negative pressure, and retention negative pressure were used as in Example 1. After pressurization and pressure holding, the pressure of the extraction chamber was continuously reduced from 3.00 MPa to 1.65 MPa. No separate intermediate retention negative pressure and intermediate negative pressure holding process were set. The subsequent retention negative pressure, first transfer, second transfer, two-stage depressurization, and centrifugation conditions were the same as in Example 1.

[0086] Test results The oil phase recovery rate, emulsion layer ratio, and relative content retention rate of active ingredients for each embodiment and comparative example are shown in Table 1.

[0087] Table 1: Oil Phase Recovery Rate, Emulsion Layer Ratio, and Retention Rate of Relative Content of Active Ingredients

[0088] The residual gas amounts for each embodiment and comparative example are shown in Table 2.

[0089] Table 2: Residual Gas Quantity Table

[0090] The oil phase recovery rate of Example 1 was higher than that of Comparative Example 1 and Comparative Example 6. In Comparative Example 1, after complete depressurization, liquid was drained, resulting in an increase in the amount of oil retained in the raw material particles and the draining path. In Comparative Example 6, after the intermediate negative pressure maintenance was cancelled, the oil phase recovery rate was lower than that of Example 1, indicating that the segmented negative pressure changes formed by the first depressurization, the intermediate negative pressure maintenance, and the second depressurization are beneficial to the subsequent collection and transfer of gas-containing oil.

[0091] The oil phase recovery rate of Example 2 was similar to that of Comparative Example 2. In Example 2, the proportion of the emulsion layer decreased from 20.77% to 13.77%, and the residual gas content decreased from 28.87 mL / kg to 14.67 mL / kg. These results indicate that in a high-water-content, pectin-containing system formed from avocado pulp, two-stage depressurization and intermittent degassing help reduce the continuous disturbance of the oil-water system by bubbles and improve the phase separation state after centrifugation.

[0092] The oil phase recovery rate of Example 3 was higher than that of Comparative Example 3, which only underwent the first transfer. In Example 3, the equivalent mass of the oil transferred in the second transfer accounted for approximately 25% of the sum of the equivalent masses of the oil transferred in both transfers. This result indicates that, at the processing temperature close to the crystallization of coconut oil, reducing the negative pressure in the collection chamber and re-establishing the negative pressure difference after the first transfer can continue to transfer some of the oil retained in the raw material bed and drainage path.

[0093] The oil phase recovery rate in Example 4 was higher than that in Comparative Example 4, where the negative pressure retention was removed. The total oil content of the grape seeds was low, and maintaining the negative pressure for 180 seconds allowed time for the dispersed oil to move towards the drainage side and collect.

[0094] The oil phase recovery rates of Example 5 and Comparative Example 5 were similar. In Example 5, the proportion of the emulsion layer decreased from 21.10% to 14.93%, and the residual gas content decreased from 24.67 mL / kg to 12.40 mL / kg. These results indicate that in animal tissues with high water and protein content, the intermittent second-stage depressurization primarily improves the degassing and stratification of the gas-containing oil that has already been transferred to the collection chamber, with little impact on the total amount of oil released during the feed stage.

[0095] Core parameter boundary verification The proportion of retained negative pressure was verified using the peony seed kernels, apparatus, and operating conditions of Example 1. The initial negative pressure for each group was 3.00 MPa, with an intermediate negative pressure of 2.40 MPa. The average rate of the first depressurization in the pressure extraction chamber was 0.075 MPa / s. By adjusting the second depressurization time, the average rate of the second depressurization in the pressure extraction chamber was maintained at 0.030 MPa / s. The gauge pressure in the collection chamber before the first transfer was set to 6% of the corresponding retained negative pressure. The first transfer ended when the pressure difference between the two chambers decreased to 0.21 MPa. The starting negative pressure for the second transfer was 50% of the gauge pressure in the collection chamber at the end of the first transfer, and the second transfer ended when the pressure difference between the two chambers decreased to 0.06 MPa. All other degassing and centrifugation conditions were the same as in Example 1. Three independent batch tests were conducted for each retained negative pressure proportion, and the average results are shown in Table 3.

[0096] Table 3: Verification Results of Negative Pressure Retention Ratio

[0097] When the retained negative pressure is less than 40% of the pressurized negative pressure, both the contribution rate of the second transfer and the oil phase recovery rate decrease, indicating that the remaining negative pressure for subsequent negative pressure differential transfer is insufficient; when the retained negative pressure is greater than 65% of the pressurized negative pressure, both the oil phase recovery rate and the contribution rate of the second transfer decrease, indicating that the decrease in negative pressure during the limited pressure relief stage is insufficient; a ratio of 40% to 65% can take into account both the oil release during the limited pressure relief stage and the subsequent staged transfers.

[0098] The second average depressurization rate ratio of the collecting chamber was verified using the gas-containing oil liquid obtained after the second transfer in Example 1. In the first stage, the pressure in the collecting chamber was reduced from 0.16 MPa to 0.07 MPa, with a depressurization time of 22.5 seconds and a first average depressurization rate of 0.004 MPa / s. The second stage consisted of two intermittent depressurizations: the first from 0.07 MPa to 0.035 MPa, and the second from 0.035 MPa to atmospheric pressure. The valve opening time for both stages was 2.5 seconds. By setting the holding time at 0.035 MPa to 170.0 seconds, 111.7 seconds, 65.0 seconds, 38.8 seconds, and 30.0 seconds, respectively, the second average depressurization rate of the collecting chamber was made to be 10%, 15%, 25%, 40%, and 50% of the first average depressurization rate. Three independent batches were performed for each ratio, and the average results are shown in Table 4.

[0099] Table 4: Verification Results of the Second Average Pressure Drop Rate Proportion in the Liquid Collection Chamber

[0100] When the ratio is below 15%, the emulsion layer ratio and residual gas volume continue to decrease, but the total time for the second stage of depressurization increases significantly; when the ratio is above 40%, the emulsion layer ratio and residual gas volume increase; a ratio of 15% to 40% can form an feasible process range between degassing effect and processing time.

[0101] The above embodiments demonstrate that the present invention can process low-moisture oilseeds, high-moisture, easily emulsified plant tissues, oil-containing tissues that are easily crystallized at low temperatures, low-oil, dense seeds, and high-moisture, high-protein animal tissues. By limiting the pressure and retaining negative pressure, transferring the oil in stages, and isolating the gaseous oil from the raw materials in two stages, an oil phase that can be further separated by centrifugation can be obtained.

[0102] The above embodiments are used to illustrate the technical solution of the present invention. Those skilled in the art can select specific operating conditions according to the raw material flow state determination method, oxygen concentration replacement endpoint, negative pressure detection accuracy, negative pressure feedback control deviation, negative pressure difference at the termination of two transfers, and segmented pressure reduction parameters disclosed in this specification; without changing the technical relationship of retaining negative pressure after limited pressure relief, transferring the remaining negative pressure in stages, and independently degassing the gas-containing oil in stages, conventional adjustments can be made within the disclosed range based on the raw material moisture content, oil viscosity, bed height, and filter media resistance.

Claims

1. A low-temperature pneumatic solvent-free extraction process for active ingredients from plants and animals, characterized in that, Includes the following steps: S1. The oily animal and plant raw materials are coarsely crushed into raw material particles and loaded into a pressure extraction chamber equipped with an air inlet and a liquid outlet. S2. Without adding liquid extractant, control the processing temperature to keep the raw material oil flowing, and introduce inert gas through the air inlet to raise the pressure extraction chamber to the negative pressure of the pressurized processing and maintain the pressure. S3. Isolate the air intake passage, reduce the pressure of the extraction chamber to the retained negative pressure through the pressure relief passage on the drain port side, and close the pressure relief passage. The retained negative pressure is 40% to 65% of the pressure treatment negative pressure. During the pressure reduction process, an oil-containing gaseous liquid is formed. S4. Adjust the negative pressure of the collection chamber to be lower than the retention negative pressure, connect the two chambers for the first transfer, and disconnect the two chambers when the negative pressure difference between the two chambers drops to 0.10MPa to 0.30MPa; reduce the negative pressure of the collection chamber separately while keeping the pressure extraction chamber isolated from the inert gas source, and then connect the two chambers for the second transfer. Disconnect the two chambers when the negative pressure difference between the two chambers drops to 0.04MPa to 0.08MPa. S5. The gas-containing oil in the collection chamber is subjected to a first stage of depressurization and a second stage of intermittent depressurization. The second average depressurization rate of the collection chamber is 15% to 40% of the first average depressurization rate of the collection chamber. After being reduced to atmospheric pressure, the oil phase containing fat-soluble active ingredients is obtained by centrifugation.

2. The low-temperature pneumatic solventless extraction process for active plant and animal components according to claim 1, characterized in that, The negative pressure of the pressurization process is 2.0 MPa to 8.0 MPa, and the raw material particles are held under the negative pressure of the pressurization process for 30 seconds to 180 seconds.

3. The low-temperature pneumatic solventless extraction process for active plant and animal components according to claim 2, characterized in that, The process by which the pressure in the extraction chamber is reduced from the pressurized negative pressure to the retained negative pressure includes, in sequence, a first pressure release, an intermediate negative pressure maintenance, and a second pressure release. The first depressurization reduces the negative pressure in the pressure-bearing extraction chamber to an intermediate, maintained negative pressure, which is 70% to 85% of the negative pressure of the pressurized treatment. After the raw material particles are held under the intermediate negative pressure for 30 to 150 seconds, the second depressurization reduces the negative pressure in the pressure-bearing extraction chamber from the intermediate negative pressure to the retained negative pressure.

4. The low-temperature pneumatic solventless extraction process for active plant and animal components according to claim 3, characterized in that, The ratio of the negative pressure drop value of the first depressurization to the first depressurization time is used as the first depressurization average speed of the pressure-bearing extraction chamber, and the ratio of the negative pressure drop value of the second depressurization to the second depressurization time is used as the second depressurization average speed of the pressure-bearing extraction chamber. The average rate of the second depressurization in the pressure-bearing extraction chamber is 25% to 50% of the average rate of the first depressurization in the pressure-bearing extraction chamber.

5. The low-temperature pneumatic solventless extraction process for active plant and animal components according to claim 1, characterized in that, After the pressure extraction chamber is reduced to the retained negative pressure, the raw material particles are kept for 30 to 180 seconds while the drain port and the collection chamber are kept separate. Then, the gas-containing oil liquid collected on the drain port side is transferred to the collection chamber.

6. The low-temperature pneumatic solventless extraction process for active plant and animal components according to claim 5, characterized in that, The gauge pressure in the collection chamber before the first transfer is 4% to 8% of the retained negative pressure; After the first transfer is completed and the two chambers are isolated, while keeping the pressure extraction chamber isolated from the inert gas source and ensuring that the increase in the surface pressure in the pressure extraction chamber does not exceed 0.01 MPa, the liquid collection chamber is reduced to the negative pressure at the start of the second transfer. The negative pressure at the start of the second transfer is 40% to 60% of the gauge pressure in the collection chamber at the end of the first transfer, and then the two chambers are connected for the second transfer.

7. The low-temperature pneumatic solventless extraction process for active plant and animal components according to claim 6, characterized in that, The second transfer ends when the negative pressure difference between the pressure-bearing extraction chamber and the liquid collection chamber drops to 0.04 MPa to 0.08 MPa; at the end of the second transfer, the gauge pressure in the pressure-bearing extraction chamber is 0.10 MPa to 0.25 MPa, which is higher than the gauge pressure in the liquid collection chamber. After the second transfer is completed, the two chambers are isolated. The gauge pressure in the liquid collection chamber is kept within the range of ±0.005MPa after the second transfer by negative pressure feedback for 60 to 180 seconds. Then, the gas-containing oil liquid is depressurized in two stages.

8. The low-temperature pneumatic solventless extraction process for active plant and animal components according to claim 7, characterized in that, The first stage of pressure reduction lowers the gauge pressure in the collection chamber to the degassing transition negative pressure, which is 30% to 50% of the collection negative pressure at the end of the second transfer. Through negative pressure feedback, the gauge pressure in the collection chamber is maintained within the range of ±0.005MPa of the degassing transition negative pressure for 60 to 300 seconds. The second stage of depressurization consists of two to four intermittent depressurizations. Between two adjacent intermittent depressurizations, negative pressure feedback is used to maintain the gauge pressure in the collection chamber within the range of the current negative pressure ±0.005MPa for 30 to 120 seconds. The last intermittent depressurization reduces the pressure in the collection chamber to atmospheric pressure. The second average depressurization rate of the collection chamber is determined by the ratio of the second stage negative pressure drop value to the total second stage depressurization time, including the time of each intermittent depressurization and the adjacent holding time.

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