Preparation method of flavor oil

Abstract

The invention relates to the technical field of edible oil processing, and discloses a preparation method of flavor grease, which comprises the following steps: cooking an oil material under a positive pressure condition, carrying out steam explosion on the cooked material, mixing the steam-exploded material with raw oil, and carrying out dehydration, aroma production, cooling and solid-liquid separation in sequence. According to the method, the content of nutrient substances (especially sterol and VE) in the oil product can be increased, the acid value and the moisture content of the oil can be further reduced, and the flavor preference degree of the oil is improved; in a preferred embodiment, the method can also realize continuous cooking steam explosion (continuous feeding and discharging of a cooker) and aroma-producing reaction, improve the efficiency and reduce the energy consumption.

Description

Technical Field

[0001] This invention relates to the field of edible oil processing technology, and more specifically to a method for preparing flavored oils. Background Technology

[0002] As people's living standards improve, consumers have higher requirements for the quality of vegetable oils. They not only require that the various physicochemical indicators of the oils meet the relevant standards, but also hope that the oils can have their own inherent natural flavor to satisfy the sensory enjoyment of flavor during cooking and eating.

[0003] Traditional flavored oil production processes typically employ drum roasters to heat oilseeds such as rapeseed, sunflower seeds, and peanuts to a specific temperature and maintain this temperature for a period of time. This allows flavor precursors in the oilseeds to undergo complex chemical reactions at high temperatures, producing a series of flavor compounds. However, the roasting process takes place in an environment where air cannot be isolated. Oxygen in the air inevitably comes into contact with the oilseeds, causing oxidation and increasing the acid value of the oil. Simultaneously, volatile flavor compounds produced during roasting inevitably escape into the surrounding atmosphere, resulting not only in flavor loss but also in air pollution around the production facility. Currently, drum roasting is an intermittent, batch operation in flavored oil production, which is not only labor-intensive but also relatively inefficient.

[0004] A relatively novel flavored oil production process has emerged in recent years. This process involves mixing oilseeds such as rapeseed, peanuts, and sunflower seeds with oil in a specific ratio, heating the mixture in a sealed container to generate flavor compounds, and then separating the flavored oilseeds and flavored edible oil through solid-liquid separation. The flavored oilseeds are then pressed to obtain a richly aromatic edible oil. Compared to traditional small-scale pressing processes, this novel flavored edible oil processing technology allows for more precise control of process conditions such as temperature, pressure, and reaction time during the aroma-generating reaction of the oilseeds. However, it still has some shortcomings. First, when oilseeds and edible oil are mixed in a sealed container and heated for aroma-generating reaction, the moisture contained in the oilseeds inevitably diffuses into the edible oil. This not only leads to an increase in the moisture content of the flavored oil obtained after solid-liquid separation, but also, under the high-temperature conditions in the extraction vessel, the increased moisture content in the oil phase inevitably intensifies the hydrolysis reaction of the oil, resulting in a significantly higher acid value in the flavored oil obtained after solid-liquid separation compared to the oil raw materials added before the reaction. Second, when using this novel aroma-generating process to produce flavored oil, since the oilseeds added to the sealed container do not undergo the high-pressure extrusion and strong shearing of oil pressing, nor the expansion or pressing process of leaching oil extraction, the cell structure of the oilseeds is not fully destroyed after the aroma-generating reaction in the sealed container. The oil, vitamin E, sterols, and other high-value nutrients contained in the cells, as well as polyphenols that can improve the antioxidant properties of oil, cannot easily diffuse through the cell wall into the oil phase during the reaction. After the reaction, whether separated by centrifugation or filtration, the resulting flavored oils will have a certain amount of liquid oil remaining between the particles. In addition, the oil content of oilseeds such as rapeseed, peanuts, and sunflower seeds is as high as about 40%, resulting in a total oil content of about 60% in the flavored oils after separation. Materials with such high oil content are too plastic and not rigid enough. Whether using screw pressing or hydraulic pressing, it is difficult to fully break down the cell walls of the oilseeds through high pressure or strong shearing. Therefore, the residual oil in the pressed cake is 2-3 times higher than that in the traditional strong aroma oil production process where oilseeds are roasted and then screw pressed. Moreover, the yield of high-value nutrients such as vitamin E and sterols in the oilseeds is also reduced during the pressing process. In addition, at present, oil production enterprises using this new aroma-producing process generally adopt a non-continuous batch operation mode for the production of flavored oils, which is still relatively inefficient.

[0005] The study "Effect of Steam Explosion Pretreatment on the Quality of Camellia Seed Oil Extracted by Water Displacement Method, Zhang Shanying, Food Science, 2019, 40(11)" discloses that steam explosion treatment and drying of camellia seeds under appropriate conditions, followed by water displacement oil extraction, can not only significantly improve the yield of camellia seed oil, but also reduce the acid value and peroxide value of camellia seed oil, and increase the iodine value, polyphenol mass concentration, and squalene and VE content of camellia seed oil. The study "Polyphenol Yield and Antioxidant Activity of Rapeseed Pretreated by Steam Explosion, Feng Chengfeng, Journal of Hunan Agricultural University, 2023, 49(5)" discloses that after steam explosion treatment of rapeseed under appropriate conditions and natural drying to reduce the moisture content to below 8%, the dried steam-exploded material was pressed at 50℃. The resulting rapeseed oil showed significantly improved polyphenol content and antioxidant capacity compared with the untreated control group. However, the research results on steam explosion treatment of oil described in these two articles were obtained on small-scale batch-operation experimental devices. The material after steam explosion needs to be dried in an oven or air-dried naturally. This oil pretreatment process with low production efficiency cannot be applied to industrial production on a large scale.

[0006] In summary, existing oilseed aroma-generating and steam-explosion pretreatment processes both employ batch-feeding operations, failing to achieve continuous production. This not only results in high labor intensity but also low production efficiency. In flavor oil production processes where flavor compounds are generated through heating a mixture of oilseeds and oils, some moisture from the oilseeds diffuses into the oil during the aroma-generating reaction. This not only significantly increases the moisture content of the flavor oil obtained after solid-liquid separation but also inevitably accelerates the hydrolysis of the oil under the high-temperature environment of the aroma-generating reaction, leading to reduced oil yield and increased acid value. (Further details regarding seed roasting and flavor oil production follow.) During the pressing process, oilseeds and oils inevitably come into contact with oxygen in the air and are oxidized, resulting in a decrease in oil quality. After soaking in oil, the oilseeds have an excessively high oil content, excessive plasticity and insufficient rigidity, which prevents the oilseed cells from being fully broken down during the pressing process. As a result, the oil cake has a high residual oil content, and high-value-added nutrients such as vitamin E and sterols in the oilseeds cannot fully penetrate the cell walls to enter the oil product. During the roasting and pressing of aromatic oils, flavor substances are severely lost, which not only reduces the flavor substance content in the oil product, but also causes pollution of the atmospheric environment around the workshop due to the volatile organic compounds released into the atmosphere. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of existing technologies that require batch operations for steam explosion pretreatment of oilseeds or for preparing flavored oils by mixing oilseeds and edible oils and then heating them. These operations cannot achieve continuous production, resulting in high labor intensity, low production efficiency, and significant loss of flavor substances and low content of nutrients (especially vitamin E and sterols) during the oil preparation process. Furthermore, some moisture from the oilseeds diffuses into the oil, leading to reduced yield, increased acid value, and decreased quality. This invention provides a method for preparing flavored oils that enables continuous steam explosion during cooking (continuous feeding and discharging of the cooker) and continuous aroma-generating reactions, thereby improving production efficiency. In addition, while increasing the content of nutrients (especially sterols and vitamin E) in the oil, this method further reduces the acid value and moisture content of the oil, improving its flavor appeal.

[0008] To achieve the above objectives, the present invention provides a method for preparing flavored oils, the method comprising: cooking oilseeds under positive pressure to cause steam explosion of the cooked material, mixing the steam-exploded material with raw oil, and then sequentially performing dehydration, aroma enhancement, cooling and solid-liquid separation.

[0009] Through the above technical solution, the present invention achieves at least the following beneficial effects: (1) In a preferred embodiment, the method of the present invention can realize continuous feeding and discharging of the cooker and continuous aroma generation reaction, which significantly improves the efficiency of oil vapor explosion treatment. (2) By using the method of the present invention, the flavor substances produced in the aroma-generating reaction can be dissolved into the oil phase more efficiently, thereby increasing the intensity of the oil flavor. At the same time, the nutrients such as VE and sterols contained in the oil cells can be released into the oil phase more fully, thereby improving the nutritional value of the flavor oil obtained after the aroma-generating reaction. (3) The method of the present invention can rapidly reduce the moisture content in oilseeds, thereby inhibiting high-temperature hydrolysis of oil during dehydration and subsequent aroma-generating reactions, further reducing the acid value and water content of the oil, thereby improving the flavor appeal of the oil. In the preferred embodiment, the moisture content in the oil is less than 0.084 g / 100 g, the acid value is less than 0.83 mg KOH / g, and the residual oil content of the cake is less than 8.8 wt%. (4) The method of the present invention can effectively increase the content of nutrients in oils (especially vitamin E and sterols). In the preferred embodiment, the content of vitamin E in the oil is as high as 685 mg / kg and the content of sterols is as high as 7620 ppm. (5) In a preferred embodiment, the present invention uses flavor-absorbing raw oil as the absorption medium, which can absorb the flavor substances generated during the steam explosion process, thereby not only improving the utilization rate of flavor substances, but also reducing the emission of air pollutants. Detailed Implementation

[0010] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0011] This invention provides a method for preparing flavored oils, the method comprising: steaming oilseeds to cause steam explosion of the steamed material, mixing the steam-exploded material with raw oil, and then sequentially performing dehydration, aroma enhancement, cooling and solid-liquid separation.

[0012] According to some embodiments of the present invention, the method further includes pulverizing the oilseeds before cooking.

[0013] Preferably, the pulverization conditions are such that the average particle size of the pulverized material is no greater than 600 μm.

[0014] According to some embodiments of the present invention, the cooking is carried out in a spiral cooker, and the mixing of the material after steam explosion with the raw material oil is carried out in a steam explosion material receiving vessel. The mixing method includes: the cooked material is sprayed from the discharge buffer chamber into the steam explosion material receiving vessel and mixed with the raw material oil preheated by the heat recovery heat exchanger in the batching vessel.

[0015] According to some embodiments of the present invention, the cooking conditions include a temperature of 120-205°C and a time of 20-240 seconds.

[0016] In this invention, the cooking method includes: simultaneously adding oil to the spiral cooker and injecting steam into the spiral cooker to directly heat the oil. To prevent excessive condensation from forming on the surface of the oil after the steam injected into the spiral cooker, resulting in excessively high moisture content, preferably, the cooking method includes: simultaneously adding oil to the spiral cooker, a heating jacket can be installed at the bottom of the spiral cooker, and steam can be introduced into the jacket to indirectly heat the oil inside the spiral cooker. The condensate formed after this steam condenses in the jacket can be discharged through a condensate drain valve, thus not increasing the moisture content of the oil. To ensure that the steam injected into the spiral cooker and its jacket can efficiently condense into liquid water to release latent heat of vaporization, preferably, saturated steam is used as the heat source for cooking.

[0017] Preferably, the mass ratio of the oilseed to the raw oil is 1:(2.5-10), and more preferably 1:(3-5).

[0018] According to some embodiments of the present invention, the positive pressure condition causes the absolute pressure within the cooking system to be 0.2-1.6 MPa.

[0019] The inventors discovered in their research that the saturated steam pressure and the duration of maintenance at that pressure vary depending on the type of oilseed being cooked. For example, the suitable saturated steam pressure for cooking rapeseed is 0.3 MPa-1.0 MPa, preferably 0.5 MPa-0.8 MPa, and the maintenance time is 30 s-210 s, preferably 60 s-150 s; the suitable saturated steam pressure for cooking peanut kernels is 0.5 MPa-1.2 MPa, preferably 0.7 MPa-1.0 MPa, and the maintenance time is 30 s-180 s, preferably 60 s-120 s; the suitable saturated steam pressure for cooking sunflower seeds is 0.2 MPa-0.8 MPa, preferably 0.7 MPa-1.0 MPa. The optimal saturated steam pressure for cooking camellia seeds is 0.6MPa-1.5MPa, preferably 0.8MPa-1.2MPa, with a holding time of 25s-150s, preferably 45s-120s. The optimal saturated steam pressure for cooking flax seeds is 0.7MPa-1.6MPa, preferably 0.9MPa-1.4MPa, with a holding time of 20s-120s, preferably 30s-90s. The residence time of the oilseeds in the cooker (i.e., cooking time) can be adjusted by regulating the frequency of the variable frequency drive motor of the screw cooker. The screw conveyor in the cooker not only propels the material forward but also agitates it, preventing uneven heating of the oilseeds.

[0020] According to some embodiments of the present invention, the steam explosion is carried out in a steam explosion material receiving vessel, and the steam explosion occurs at the moment when the cooked material is sprayed into the steam explosion material receiving vessel from below the outlet of the spiral cooker.

[0021] In this invention, the oilseeds are heated and cooked with steam in a spiral digester. The heated material is then conveyed to the discharge buffer bin by a spiral conveyor arranged within the digester. During the process of the material being injected from the discharge buffer bin into the steam-explosion material receiving vessel under steam pressure, the sudden drop in ambient pressure causes flash evaporation of some of the liquid water on the surface and inside the oilseed particles, instantly generating a large amount of steam. This rapid expansion in volume produces an effect similar to an explosion; this process is the steam-explosion treatment of the oilseeds. Under the strong shearing action of the explosion shock wave, the oilseed's structure is destroyed, and the cell walls rupture, allowing the oils and other nutrients contained in the oilseed to be released more fully from the oilseed cells during subsequent processing.

[0022] According to some embodiments of the present invention, the steam explosion mode is selected from atmospheric pressure steam explosion and / or negative pressure steam explosion.

[0023] In this invention, atmospheric pressure steam explosion refers to the process where the cooked oil is sprayed into the steam explosion receiving vessel under the steam pressure within the spiral cooker, while the receiving vessel remains at atmospheric pressure. Negative pressure steam explosion, on the other hand, refers to the process where the cooked oil is sprayed into the receiving vessel under the steam pressure within the spiral cooker, while the internal space of the receiving vessel remains under negative pressure. To reduce the water content of the oil, inhibit the hydrolysis of the oil at high temperatures during subsequent aroma-generating reactions, and reduce the acid value of the oil, the steam explosion method is preferably negative pressure steam explosion.

[0024] Preferably, the negative pressure steam explosion condition is such that the absolute pressure inside the steam explosion material receiving vessel is 0.02-0.08 MPa.

[0025] In this invention, the inventors discovered that after steam explosion and dehydration, excessively high moisture content in the material is detrimental to reducing the acid value and moisture content of the flavor oil obtained after the aroma-generating reaction. However, if the moisture content of the material entering the extraction vessel for the aroma-generating reaction is too low, it will lead to a decrease in the flavor liking score of the flavor oil. According to some embodiments of the present invention, the dehydration is carried out in a steam-exploded material receiving vessel, and the dehydration conditions are such that the moisture content of the dehydrated mixture is 0.5wt%-2wt%, preferably 1wt%-2wt%, and more preferably 1.2wt%-1.8wt%.

[0026] Preferably, the method further includes preheating the raw oil before mixing it with the vapor-exploded material. The inventors have found that, under the same pressure inside the vapor-exploded material receiving vessel, although a higher preheating temperature of the raw oil results in higher dehydration efficiency of the vapor-exploded material, if the preheating temperature is too high, the raw oil itself will hydrolyze while heating the vapor-exploded material. Controlling the preheating temperature of the raw oil below 125°C can effectively suppress the hot hydrolysis reaction during the dehydration process. Preferably, the preheating conditions result in a raw oil temperature of 95-125°C.

[0027] In this invention, the preheating method of the feedstock oil can be achieved by using a medium such as steam as a heat source to indirectly heat the feedstock oil. To improve thermal energy utilization efficiency, preferably, the preheating method of the feedstock oil includes: exchanging heat between the feedstock oil and high-temperature materials from the extraction vessel to recover thermal energy.

[0028] According to some embodiments of the present invention, the dehydration conditions include: a temperature of 85-125°C and a time of 20-60 min.

[0029] According to some embodiments of the present invention, the dehydration method is selected from atmospheric pressure dehydration and / or negative pressure dehydration.

[0030] In this invention, atmospheric pressure dehydration refers to the process where the dehydration vessel for the dehydrated material after steam explosion is kept at atmospheric pressure after mixing with the raw oil; while negative pressure dehydration refers to the process where the dehydration vessel for the dehydrated material after steam explosion is kept at negative pressure after mixing with the raw oil. To enhance the dehydration effect and improve the dehydration efficiency of the dehydrated material, preferably, the dehydration method is negative pressure dehydration.

[0031] Preferably, the negative pressure dehydration conditions result in an absolute pressure of 0.02-0.08 MPa inside the steam-exploded material receiving vessel.

[0032] In order to keep the gas explosion material receiving vessel under negative pressure, preferably, a vacuum pump can be used to maintain a certain degree of vacuum in the gas explosion material receiving vessel.

[0033] In a preferred embodiment of the present invention, the vacuuming equipment is preferably selected from conventional vacuuming equipment such as water ring vacuum pumps, jet vacuum pumps, and Roots vacuum pumps. For example, the gas phase outlet at the top of the steam explosion material receiving vessel is connected to the air inlet of the water ring vacuum pump through a pipeline, so that the cooked oil undergoes steam explosion and dehydration under vacuum conditions. The water ring vacuum pump extracts the water vapor and volatile organic gases generated during the steam explosion process from the steam explosion material receiving vessel. The extracted water vapor and water-soluble organic gases are absorbed by the circulating water of the water ring vacuum pump and periodically discharged from the gas-water separator to the sewage treatment plant for treatment. Organic gases and non-condensable gases that cannot be absorbed by water are discharged into the atmosphere from a high point through a chimney as exhaust gas.

[0034] In this invention, during the cooking process, water vapor condenses into liquid water on the surface of the oilseeds, leading to a further increase in the water content of the oilseeds. Although the steam explosion process causes some of the water in the oilseeds to vaporize and escape as water vapor, the water content of the oilseeds after steam explosion treatment is still relatively high. The inventors discovered during experiments that if the steam-exploded oilseeds are directly mixed with the raw oil and heated for an aroma-generating reaction, although flavor substances can be produced, the acid value of the flavored oil product obtained through solid-liquid separation after the reaction increases significantly. This invention also discovered that by mixing and heating preheated raw oil to a certain temperature with the steam-exploded oil in a steam-explosion material receiving vessel, some of the water in the oil is vaporized, and the generated water vapor is discharged through the steam outlet of the steam-explosion material receiving vessel, thereby reducing the water content of the steam-exploded oil to a certain level. Then, it is pumped together with the aroma-enhancing raw oil to an extraction vessel for further heating to a certain temperature for a period of time to enhance the aroma. After the reaction is completed, the material is cooled and solid-liquid separated. The resulting liquid product, i.e., the flavored oil product, not only shows a significantly reduced increase in acid value, but also has a better flavor.

[0035] According to some embodiments of the present invention, the aroma generation is carried out in an extraction vessel; the conditions for aroma generation include: a temperature of 125-210°C and a time of 20-180 min.

[0036] The inventors discovered that the suitable aroma-enhancing reaction temperature and time vary for different types of oilseeds. For example, the suitable aroma-enhancing reaction temperature for rapeseed is 140-180℃, preferably 150-170℃, and the reaction time is 30-120 minutes, preferably 45-90 minutes; the suitable aroma-enhancing reaction temperature for peanut kernels is 150-200℃, preferably 165-190℃, and the reaction time is 20-150 minutes, preferably 50-100 minutes; the suitable aroma-enhancing reaction temperature for sunflower seeds is 125-165℃, preferably 135-155℃. The optimal temperature for aroma development in the extraction vessel is 160-210℃, preferably 170-195℃, with a reaction time of 30-120 min, preferably 50-100 min. For shelled camellia seeds, the optimal temperature is 150-190℃, preferably 160-180℃, with a reaction time of 30-150 min, preferably 60-120 min. The temperature of the aroma development reaction in the extraction vessel can be controlled by adjusting the flow rate and / or temperature of the heating medium injected into the jacket or heating coil of the extraction vessel. The heating medium used is typically saturated steam or heat transfer oil.

[0037] According to some embodiments of the present invention, the cooling is carried out in a cooling kettle; the cooling conditions are such that the temperature of the mixture after aroma generation does not exceed 90°C, preferably 35-65°C.

[0038] According to some embodiments of the present invention, the solid-liquid separation method is selected from centrifugation and / or filtration, preferably centrifugation and filtration. More specifically, centrifugation is performed using a horizontal screw centrifuge, and the resulting supernatant is then filtered sequentially through a leaf filter and a precision bag filter to obtain flavored oil.

[0039] According to some embodiments of the present invention, the water content of the oil is 7-13%.

[0040] According to some embodiments of the present invention, a discharge buffer chamber is provided below the discharge port of the spiral cooker, and the lower part of the discharge buffer chamber is connected to the steam explosion material receiving vessel.

[0041] Preferably, the discharge buffer hopper is equipped with a material level detector and a pulse switching valve.

[0042] Preferably, the outlet of the pulse switching valve is connected to the steam explosion material receiving vessel.

[0043] Alternatively, a discharge buffer chamber may be provided below the discharge port of the spiral cooker, and a discharge auger may be provided at the lower part of the discharge buffer chamber, with the discharge port of the discharge auger connected to the steam explosion material receiving vessel.

[0044] According to some embodiments of the present invention, the feed inlet of the spiral cooker is connected to feed buffer chamber A and feed buffer chamber B respectively through a discharge pipe; the feed inlets of feed buffer chamber A and feed buffer chamber B are connected to the discharge outlet of the cooker feed auger respectively through feed pipes.

[0045] According to some embodiments of the present invention, the feed pipes connecting the feed auger of the cooker to the feed buffer chamber A and the feed buffer chamber B are respectively equipped with feed valves V2A and V2B.

[0046] According to some embodiments of the present invention, the discharge ports of the feed buffer chamber A and the feed buffer chamber B are respectively provided with rotary discharge valves V4A and V4B; the discharge pipes connecting the feed buffer chamber A and the feed buffer chamber B to the spiral cooker are respectively provided with feed valves V5A and V5B.

[0047] According to some embodiments of the present invention, an exhaust valve V1A and a steam valve V3A are respectively provided on the top of the feed buffer chamber A.

[0048] According to some embodiments of the present invention, an exhaust valve V1B and a steam valve V3B are respectively provided on the top of the feed buffer chamber B.

[0049] In this invention, the valves on feed buffer chamber A and feed buffer chamber B can be used to switch between the two feed buffer chambers, thereby enabling continuous feeding into the spiral cooker.

[0050] According to some embodiments of the present invention, the discharge port at the bottom of the gas explosion material receiving vessel is connected to the inlet at the top of the extraction vessel via a pipe; the discharge port at the bottom of the extraction vessel is connected to the inlet at the top of the cooling vessel via a pipe.

[0051] Preferably, a heat recovery heat exchanger is installed on the pipe connecting the extraction vessel and the cooling vessel; the heat recovery heat exchanger is connected to the steam explosion material receiving vessel through a feed pipe.

[0052] In this invention, when oilseeds are heated by steam in a cooker, they release flavor compounds during the steam explosion process. If these flavor compounds escape into the surrounding atmosphere, it will not only result in the loss of flavor compounds but also cause air pollution around the production facility. During experimentation, the inventors unexpectedly discovered that most of these flavor compounds can be absorbed by edible vegetable oil, and that the vegetable oil, after absorbing these flavor compounds, possesses a flavor similar to that of concentrated oil produced using a small-scale pressing process. Therefore, as a preferred solution, using flavor-absorbing raw oil as the absorption medium to absorb the flavor compounds generated during steam explosion and subsequent dehydration not only improves the utilization rate of flavor compounds but also reduces the emission of air pollutants.

[0053] Preferably, the method includes: connecting the gas phase outlet at the top of the gas explosion material receiving vessel to the inlet of a vacuum pump via a pipeline; the vacuum pump is an oil ring vacuum pump; the inlet of the oil-gas separator of the oil ring vacuum pump is connected to the outlet of the oil ring vacuum pump; the raw material oil for absorbing flavor substances (flavor absorption raw material oil) is injected into the oil-gas separator of the oil ring vacuum pump via a pipeline. The gas phase outlet of the oil-gas separator is connected to the gas phase inlet of the absorption tower, and one liquid phase outlet of the oil-gas separator is connected to the liquid phase inlet of the oil ring vacuum pump, so that the flavor absorption raw material oil can circulate between the pump body and the oil-gas separator as the working medium of the oil ring vacuum pump; the liquid phase overflow port of the oil-gas separator is connected to the liquid phase inlet of the flavor substance absorption tower, so that the flavor absorption raw material oil in the oil-gas separator can enter the flavor substance absorption tower by overflow, and is sprayed onto the packing in the absorption tower by a circulating pump, where it comes into countercurrent contact with the flavor substances from the oil-gas separator, thereby absorbing the flavor substances discharged from the oil-gas separator to generate flavor substance absorption oil.

[0054] According to a preferred embodiment of the present invention, a method for absorbing flavor substances generated during the steam explosion process using flavor-absorbing feed oil is described in detail: The exhaust port at the top of the steam explosion material receiving vessel is connected to an oil ring vacuum pump of an oil-gas separation device via a pipeline. Water vapor and volatile organic compounds such as flavor substances generated during the steam explosion and heating process are discharged from the exhaust port at the top of the steam explosion material receiving vessel and enter the oil ring vacuum pump through the pipeline. The flavor-absorbing feed oil (which can be primary, secondary, or tertiary edible oil) is continuously injected into the oil-gas separator of the oil-gas separation device. Water vapor and flavor substances extracted from the steam explosion material receiving vessel are mixed with the flavor-absorbing feed oil from the oil-gas separator in the oil ring vacuum pump. A portion of the water vapor and flavor substances are condensed and absorbed by the flavor-absorbing feed oil. The un-condensed water vapor and flavor substances are separated from the flavor-absorbing feed oil in the oil-gas separator and enter the absorption tower from the gas phase inlet at the bottom of the absorption tower. The flavor-absorbing feed oil injected into the oil-gas separator flows into the bottom of the absorption tower through an overflow pipeline. The oil is then pumped to the top of the absorption tower via a circulating pump and sprayed onto the packing material through a distributor. Flavor substances and water vapor entering the absorption tower from the gas inlet come into countercurrent contact with the oil phase from the top of the tower on the packing surface. Most of the flavor substances are absorbed by the oil phase. A stream is then drawn from the outlet pipeline of the circulating pump and transported to a precision filter for filtration, before being discharged as flavor absorption oil. The remaining uncondensed and unabsorbed gas is discharged into the atmosphere through the exhaust pipe at the top of the absorption tower. While the flavor absorption feedstock absorbs flavor substances in the absorption tower, most of the water vapor evaporated during the vapor explosion and dehydration processes condenses into liquid water and enters the flavor absorption feedstock. Because the oil and water phases are immiscible and have a density difference, the two phases can be separated by allowing them to settle and separate at the bottom of the absorption tower. This water is then periodically discharged to a wastewater treatment plant through a water separator at the bottom of the tower.

[0055] In this invention, flavor substances and water vapor in the exhaust gas of the oil ring vacuum pump release heat when absorbed by the flavor absorption feedstock oil or condensed into liquid on the packing surface, causing the temperature of the flavor absorption feedstock oil to rise. To avoid a decrease in the absorption effect of flavor substances due to excessively high absorption medium temperature, an absorption oil condenser is required to cool the absorption medium. Studies have found that maintaining the temperature of the absorption medium inside the absorption tower below 50°C achieves a satisfactory absorption effect.

[0056] In this invention, the flavor-absorbing raw oil absorbs the flavor substances generated during the steam explosion process, and the resulting flavor-absorbing oil can be used as a flavor oil product on its own or as a component added to other strong-aroma oil products.

[0057] In this invention, both the raw material oil and the flavor absorption raw material oil are edible vegetable oils obtained by pressing or leaching oilseeds and refining them to a certain extent, such as first-grade, second-grade, or third-grade edible vegetable oils (e.g., first-grade edible vegetable oil purchased from Fulinmen). The oilseeds used for the raw material oil and the flavor absorption raw material oil can be of the same type or different types.

[0058] In this invention, the oilseeds suitable for use in the production of various common vegetable oils can be oilseeds, including but not limited to rapeseed oil, sunflower seed oil, peanut oil, corn germ oil, tea seed oil, cottonseed oil, sesame seed oil, flaxseed oil, sesame seed oil, soybean oil, palm fruit oil, palm oil, palm kernel oil, rice bran oil, safflower seed oil, perilla seed oil, coconut oil, olive oil, cocoa bean oil, almond oil, apricot kernel oil, tung seed oil, rubber seed oil, wheat germ oil, evening primrose seed oil, hazelnut oil, walnut oil, pecan oil, grape seed oil, sea buckthorn seed oil, tomato seed oil, pumpkin seed oil, and other vegetable oils. The oilseeds suitable for use in this invention can be a single type of oilseed or a mixture of multiple oilseeds. According to a preferred embodiment of this invention, the seeds used to prepare the raw material oil are the same as the oilseeds.

[0059] In some embodiments of the present invention, the oilseeds used to prepare flavored oils include, but are not limited to, at least one of rapeseed, peanut kernels, sunflower kernels, camellia seeds, flaxseeds, corn germ, walnuts, and sesame seeds.

[0060] According to one embodiment of the present invention, the steam explosion cooking device includes a feeding auger, a feeding buffer chamber, a spiral cooker, and a steam explosion material receiving vessel. The feeding buffer chamber includes feeding buffer chamber A and feeding buffer chamber B. The top of feeding buffer chamber A is respectively equipped with an exhaust valve V1A and a steam valve V3A, and the top of feeding buffer chamber B is respectively equipped with an exhaust valve V1B and a steam valve V3B. The inlets of feeding buffer chambers A and B are respectively connected to the outlet of the feeding auger via feeding pipes. The feeding buffer chambers A and B are connected to the feeding auger via (inlet / outlet / pipe). Feed valves V2A and V2B are respectively installed on the feed pipeline; the discharge ports of feed buffer chambers A and B are respectively connected to the feed port of the spiral cooker through discharge pipelines. A rotary discharge valve V4A is installed at the discharge port of feed buffer chamber A, and a rotary discharge valve V4B is installed at the discharge port of feed buffer chamber B. Feed valves V5A and V5B are respectively installed on the discharge pipelines connecting feed buffer chambers A and B to the spiral cooker. The spiral cooker is connected to the steam explosion material receiving vessel through a discharge buffer chamber; a material level detector and a pulse switching valve are installed on the discharge buffer chamber.

[0061] Specifically, the cleaned and purified oil is conveyed to the feed buffer silo A via the feed auger of the digester. When the material level in the feed buffer silo A reaches the upper limit of the set value, the exhaust valve V1A and feed valve V2A at the top of the silo are first closed. Then, the steam inlet valve V3A is opened to introduce steam into the silo, thereby balancing the steam pressure in the feed buffer silo A and the spiral digester. Next, the feed valve V5A of the spiral digester and the rotary discharge valve V4A on the feed buffer silo A are opened to add the oil from the buffer silo A into the spiral digester. The feeding speed into the spiral digester can be adjusted by frequency conversion of the rotation speed of the rotary discharge valve V4A. While feeding material into the spiral cooker through feed buffer chamber A, oil is added to feed buffer chamber B through the cooker feed auger using the same feeding method as feed buffer chamber A. When the material level in this chamber reaches the set upper limit, the cooker feed auger is stopped, and the exhaust valve V1B and feed valve V2B of cooker feed chamber B are closed. When the material level in cooker feed buffer chamber A drops to near the set lower limit, V3B is opened to establish pressure connection between cooker feed buffer chamber B and spiral cooker. Then, V4B and V5B are opened sequentially, V4A, V5A, and V3A are closed, and V1A, V2A, and cooker feed auger are opened. This switches the feed to the spiral cooker from feed buffer chamber A to feed buffer chamber B, while simultaneously starting to load material into cooker feed buffer chamber A. This cycle is repeated, and continuous feeding into the spiral cooker is achieved by switching between the two feed buffer chambers.

[0062] According to one embodiment of the present invention, a flavored oil production system includes a steam explosion cooking device (including a feeding auger, a feeding buffer bin, a spiral cooker, and a steam explosion material receiving vessel), an extraction vessel, and a cooling vessel; wherein, the steam explosion material receiving vessel is at atmospheric pressure, and water vapor and volatile organic compounds such as flavor substances generated during the spraying and heating of the oil are discharged from the exhaust port at the top of the steam explosion material receiving vessel; the discharge port at the bottom of the steam explosion material receiving vessel is connected to the inlet at the top of the extraction vessel via a pipeline; the discharge port at the bottom of the extraction vessel is connected to the inlet at the top of the cooling vessel via a pipeline, and a heat recovery heat exchanger is installed on the pipeline connecting the extraction vessel and the cooling vessel.

[0063] While adding oil to the spiral digester, heating steam is introduced to directly heat the oil. A pressure regulation valve maintains a constant steam pressure within the digester. The residence time of the oil within the digester is controlled by adjusting the frequency of the digester's variable frequency drive motor. To prevent excessive condensation from the steam injected into the digester, which would result in high moisture content, a heating jacket can be installed at the bottom of the digester. Steam is introduced into this jacket to indirectly heat the oil. The condensate formed by this steam in the jacket is discharged through a condensate drain valve, thus not increasing the oil's moisture content. During the cooking process, the material entering the spiral digester is pushed to the discharge buffer bin by a spiral conveyor. The conveyor not only moves the material forward but also agitates it, preventing uneven heating.

[0064] A level detector is installed at the top of the discharge buffer silo. An electrically or hydraulically driven pulse switch valve is installed between the discharge buffer silo and the steam explosion material receiving vessel. When the level detector detects that the material level in the discharge buffer silo has reached the set upper limit, it triggers the pulse switch valve to open rapidly. A stream of material in the discharge buffer silo is injected into the steam explosion material receiving vessel below under the pressure inside the silo. Then the pulse switch valve immediately closes to prevent the material in the buffer silo from being emptied, which would cause steam in the cooker to leak into the steam explosion material receiving vessel through the valve. The raw material oil (preferably refined first-grade vegetable oil preheated to a certain temperature) is injected into the steam-explosion material receiving vessel and mixed with the steam-explosion treated oil. Steam is injected into the outer coil of the steam-explosion material receiving vessel to heat the mixture inside the vessel. Some of the water in the oil is vaporized by the heat, and the generated water vapor is discharged through the steam outlet of the steam-explosion material receiving vessel, so that the water content of the steam-explosion oil is reduced to a certain level. Then, the mixture of dehydrated oil and raw material oil is pumped to the extraction vessel through the discharge pump of the steam-explosion material receiving vessel. Steam is injected into the outer coil of the extraction vessel to heat the material inside the vessel. The flavor substances produced by the aroma-generating reaction of the oil at high temperature are absorbed by the aroma-generating raw material oil, thereby giving the aroma-generating raw material oil a rich flavor.

[0065] The inventors discovered that the suitable aroma-generating reaction temperature and reaction time vary for different types of oilseeds after steam explosion treatment. For example, the suitable aroma-generating reaction temperature for rapeseed is 135-175℃, preferably 145-170℃, and the reaction time is 30-120 min, preferably 45-90 min; the suitable aroma-generating reaction temperature for peanut kernels is 150-195℃, preferably 160-185℃, and the reaction time is 30-150 min, preferably 60-120 min; the suitable aroma-generating reaction temperature for sunflower seeds is 125-155℃, preferably 130-150℃. The aroma-generating reaction time is 30-150 min, preferably 45-120 min; the suitable aroma-generating reaction temperature for dehulled camellia seeds is 150-200℃, preferably 160-190℃, and the aroma-generating reaction time is 45-180 min, preferably 60-120 min; the suitable aroma-generating reaction temperature for flax seeds is 150-180℃, preferably 160-170℃, and the aroma-generating reaction time is 60-180 min, preferably 75-120 min.

[0066] In this invention, the material after the reaction is completed is pumped to the heat recovery heat exchanger by the extraction vessel discharge pump. Heat exchange takes place in the heat recovery heat exchanger (serpentine tube heat exchanger). After the material is cooled down by heat exchange, it enters the cooling vessel and exchanges heat with the circulating cooling water in the jacket of the vessel. The temperature of the material in the cooling vessel is maintained at about 50°C by adjusting the flow rate of the circulating cooling water. The cooled material is discharged from the bottom of the cooling vessel for solid-liquid separation to obtain the flavored oil.

[0067] In this invention, the discharge device of the spiral digester can also be replaced in the following way: Specifically, a discharge buffer chamber is set below the discharge port of the spiral digester, and a discharge auger is set at the lower part of the chamber. The spiral shaft of the discharge auger has two smooth shaft sections without spiral blades, and a narrowing section is set at its outlet. This structural design allows the material to be compressed while being conveyed forward in the discharge auger. This allows for the continuous discharge of material from the discharge buffer chamber into the steam explosion receiving vessel, while simultaneously sealing the steam pressure inside the digester through a plug formed by the compressed material, preventing uncontrolled leakage of material from the discharge buffer chamber under steam pressure. Furthermore, maintaining a certain material level in the discharge buffer chamber to form a material seal at the discharge port of the spiral digester also helps prevent steam leakage from the digester. By adjusting the discharge speed of the discharge auger using frequency conversion, the material level in the discharge buffer chamber can be kept stable.

[0068] According to a preferred embodiment of the present invention, a vacuum device is added to the flavored oil production system to maintain a certain vacuum level inside the steam-explosion material receiving vessel. Specifically, the gas phase outlet at the top of the steam-explosion material receiving vessel is connected to the inlet of a water ring vacuum pump via a pipe, maintaining a negative pressure state in the steam-explosion material receiving vessel, thereby allowing the cooked oil to undergo steam explosion and dehydration under vacuum conditions. The water ring vacuum pump extracts the water vapor and volatile organic gases generated during the steam explosion process from the steam-explosion material receiving vessel. The extracted water vapor and water-soluble organic gases are absorbed by the circulating water of the water ring vacuum pump and periodically discharged from the gas-liquid separator to a wastewater treatment plant for treatment. Organic gases and non-condensable gases that cannot be absorbed by water are discharged into the atmosphere from a high point through a chimney as exhaust gas.

[0069] According to a more preferred embodiment of the present invention, the flavor oil production system is further equipped with a flavor substance absorption device for absorbing water vapor and flavor substances generated during the steam explosion and aroma generation processes of the oil. Specifically, a stream of flavor absorption feedstock oil can be introduced into the oil-gas separator of the oil ring vacuum pump. The feedstock oil in this tank serves as both the working medium of the oil ring vacuum pump and the absorption medium for flavor substances generated during the steam explosion and dehydration processes, thus preparing flavor absorption oil. The flavor absorption feedstock oil injected into the oil-gas separator overflows into the bottom of the absorption tower. The absorption tower circulation pump pumps the oil from the bottom of the tower to the top of the absorption tower, where it is sprayed onto the packing material inside the absorption tower through atomizing nozzles. The oil comes into countercurrent contact with the exhaust gas from the vacuum pump below the packing material on the surface of the packing material to absorb the flavor substances in the exhaust gas. A stream of oil is led out from the outlet pipeline of the absorption tower circulation pump and transported to a precision filter for filtration, and then discharged as the flavor absorption oil. The flow rate of the flavor absorption oil product is adjusted by a flow regulating valve to keep the liquid level in the bottom of the absorption tower stable. While absorbing flavor substances generated during steam explosion in the absorption tower, the flavor absorption feedstock also causes most of the water vapor flashed during the steam explosion to condense into liquid water, which then enters the flavor absorption feedstock. Because the oil and water phases are immiscible and have a density difference, the oil and water phases can be separated by allowing them to settle and separate in the bottom of the absorption tower. This water is then periodically discharged to a wastewater treatment plant through a water separator in the bottom of the tower. This process setup ensures that the flavor substances generated during steam explosion are fully absorbed by the flavor absorption feedstock, thus effectively utilizing the flavor substances produced during steam explosion and dehydration, while also reducing the amount of organic waste gas emitted into the atmosphere.

[0070] The present invention will be described in detail below through embodiments.

[0071] In the following examples and comparative examples, the filling factor of the feed buffer bin refers to the proportion of the material in the buffer bin to the total volume of the buffer bin, that is, the filling factor of the feed buffer bin = the volume of the filler / the volume of the container.

[0072] In the following examples and comparative examples, the moisture content of rapeseed is 12.8 wt%, the moisture content of peanut kernels is 9.8 wt%, the moisture content of sunflower seeds is 11.6 wt%, the moisture content of dehulled camellia seeds is 12.7 wt%, and the moisture content of flaxseed is 7.2 wt%.

[0073] In the following examples and comparative examples, the horizontal screw centrifuges were purchased from Jiangsu Juneng Machinery Co., Ltd., and the equipment model is LW350.

[0074] In the following examples and comparative examples, the blade filter was purchased from Jiangsu Juneng Machinery Co., Ltd., and the equipment model is NYB-15.

[0075] In the following examples and comparative examples, the precision bag filter was purchased from Shanghai Qingshang Filtration Equipment Co., Ltd., and the equipment model is QSSL4-1.

[0076] In the following examples and comparative examples, the disc centrifuges were purchased from Jiangsu Juneng Machinery Co., Ltd., and the equipment model is DHZ-380.

[0077] In the following examples and comparative examples, the screw oil press was purchased from Shenqiu County Wanxiang Machinery Factory, and the equipment model is 6YL-95.

[0078] The steam pressures in the following examples and comparative examples are gauge pressures.

[0079] The aroma-generating reaction raw material oil and flavor-absorbing raw material oil in the following examples and comparative examples are all first-grade edible vegetable oils obtained by pressing or leaching oilseeds and refining them, such as first-grade rapeseed oil, first-grade peanut oil and first-grade sunflower seed oil purchased from the Fulinmen brand.

[0080] In the following examples and comparative examples, the acid value of the oils was determined according to GB / T 5530-2005 Determination of Acid Value and Acidity of Animal and Vegetable Oils; the moisture content of the oils was determined according to GB / T 26626-2011 Determination of Moisture Content of Animal and Vegetable Oils by Karl Fischer Method.

[0081] In the following examples and comparative examples, the flavor evaluation method includes: selecting 10 professional evaluators according to sensory evaluation requirements to evaluate the flavor of the oil from two dimensions: flavor intensity and flavor preference, with a full score of 5 points.

[0082] To eliminate the influence of the raw oil to oilseed mass ratio during the aroma-generating reaction on the sample test results, before evaluating the flavor of the flavored oils and detecting their vitamin E and sterol content, different multiples of primary oil were added to the flavored oils obtained after filtration and separation, based on the mass ratio of oilseeds to raw oil (primary oil) used in the production of the flavored oils. The amount of oilseeds corresponding to each unit mass of flavored oil sample used for evaluation was the same. The diluted samples were then used for flavor evaluation and nutrient content detection. For example, if the mass ratio of oilseeds to primary oil added during the aroma-generating reaction was 1:4, then 5 times the amount of primary oil was added to the sample for flavor evaluation; if the ratio was 1:5, then 4 times the amount of primary oil was added to the sample after filtration and separation; and if the ratio was 1:3, then 6.66 times the amount of primary oil was added to the sample after filtration and separation. The pressed aromatic oil obtained from the flavor oilseeds after solid-liquid separation was diluted 10 times with first-grade oil before flavor evaluation.

[0083] When evaluating the flavor of flavor-absorbing oils, the mass ratio of the raw oil used for flavor absorption to the oil used for aroma-generating reactions is 3:1. Different multiples of flavor-absorbing raw oil (Grade 1 oil) are added to the flavor-absorbing oil to dilute the sample, ensuring that the amount of oil per unit mass of flavor-absorbing oil sample is the same for flavor evaluation. For example, if the mass ratio of Grade 1 raw oil used for flavor absorption to the oil used for aroma-generating reactions is 2:1, the sample is diluted 1.5 times before evaluation; if the mass ratio is 2.5:1, the sample is diluted 1.2 times before evaluation; and if the mass ratio is 3:1, no dilution is needed, and the flavor-absorbing oil is evaluated directly.

[0084] In the following examples and comparative examples, the residual oil content of the pressed cake was determined according to GB / T 6433-2006 Determination of crude fat in feed.

[0085] Example 1 Flavored rapeseed oil is produced using rapeseed and first-grade rapeseed oil as raw materials. In the flavored oil production system used in this embodiment, the steam explosion material receiving vessel is at atmospheric pressure, and the water vapor and volatile organic compounds such as flavor substances generated during the steam explosion and dehydration of rapeseed are discharged from the exhaust port at the top of the steam explosion material receiving vessel.

[0086] After cleaning and removing impurities, the rapeseed is crushed to an average particle size of approximately 300 μm and then conveyed to feed buffer silo A via the feed auger of the digester. When the material height in feed buffer silo A reaches the upper limit of the set value (the filling coefficient of feed buffer silo A reaches 0.95), the exhaust valve V1A and feed valve V2A at the top of feed buffer silo A are first closed. Then, the steam inlet valve V3A is opened to introduce steam into feed buffer silo A, thereby balancing the steam pressure in feed buffer silo A and the spiral digester. Next, the feed valve V5A and the rotary discharge valve V4A on feed buffer silo A are opened to add the oilseeds from feed buffer silo A into the spiral digester. Simultaneously with the addition of oilseeds into the spiral digester through feed buffer silo A, oilseeds are added to feed buffer silo B via the feed auger of the digester using the same feeding method as feed buffer silo A. When the material height in feed buffer chamber B reaches the set upper limit (when the filling coefficient of feed buffer chamber B reaches 0.95), the feed auger of the cooker is stopped, and the exhaust valve V1B and feed valve V2B of feed chamber B are closed. When the material in feed buffer chamber A of the cooker is nearly emptied (when the filling coefficient of feed buffer chamber A drops to 0.05), V3B is opened to achieve pressure connection between feed buffer chamber B and the spiral cooker. Then, V4B and V5B are opened in sequence, V4A, V5A and V3A are closed, and V1A, V2A and the feed auger of the cooker are opened. In this way, the feeding of the spiral cooker is switched from feed buffer chamber A to feed buffer chamber B, and at the same time, the feeding of feed buffer chamber A of the cooker begins. This cycle is repeated. By switching between the two feed buffer chambers, continuous feeding into the spiral cooker is achieved.

[0087] By adjusting the pressure reducing valve on the steam inlet pipeline of the spiral digester, the pressure of saturated steam in the inner cavity and heating jacket of the spiral digester is maintained at 0.8 MPa. The rotational speed of the spiral shaft of the digester is adjusted by a frequency converter, ensuring that the oil reaches the discharge port approximately 60 seconds after entering the digester, and is then sprayed into the explosion material receiving vessel via a pulse switching valve. The aroma-generating reaction feedstock oil (first-grade rapeseed oil) is heated to 95°C after heat exchange with the high-temperature material discharged from the extraction vessel via a heat recovery heat exchanger, and then enters the explosion material receiving vessel to mix with the explosion material. The mass ratio of first-grade rapeseed oil injected into the explosion material receiving vessel per hour to the rapeseed processed by the system per hour is controlled at 4:1. Heating steam is injected into the external coil of the explosion material receiving vessel to maintain the temperature of the mixture (exploded rapeseed powder and first-grade rapeseed oil) in the explosion material receiving vessel at 125°C. By controlling the material level in the explosion material receiving vessel, the average residence time of the material entering the vessel is controlled to be 20 minutes. The water vapor and volatile organic compounds such as flavor substances generated during the process of the material being sprayed into the steam explosion material receiving vessel and heated and dehydrated in the vessel are discharged from the exhaust port at the top of the steam explosion material receiving vessel. When the material is discharged from the steam explosion material receiving vessel after steam explosion and dehydration, its moisture content is reduced to 2wt%.

[0088] The mixture in the steam-exploded material receiving vessel is pumped to the extraction vessel for aroma generation via a discharge pump. The temperature of the material in the extraction vessel is maintained at 175℃ by adjusting the flow rate of heating steam injected into the external coil. The average residence time of the material in the extraction vessel is controlled to 45 minutes by adjusting the liquid level.

[0089] The mixture in the extraction vessel is pumped to the inner tube of the serpentine heat exchanger by the discharge pump of the extraction vessel. It exchanges heat with the aroma-producing raw material oil injected into the outer tube of the heat exchanger. After the mixture is cooled by heat exchange, it enters the cooling vessel and exchanges heat with the circulating cooling water in the jacket of the vessel. The temperature of the material in the cooling vessel is maintained at 50°C by adjusting the flow rate of the circulating cooling water. After the cooled material is discharged from the bottom of the cooling vessel, it is first separated into solid and liquid by a horizontal screw centrifuge at a speed of 3100 r / min to obtain the supernatant and flavor oil. The supernatant obtained is then filtered sequentially through a leaf filter and a precision bag filter to obtain flavored rapeseed oil. The flavored oilseeds discharged from the horizontal screw centrifuge are pressed through a screw oil press to obtain pressed crude oil and press cake. After filtering the pressed crude oil to remove residue, 2% pure water by weight of crude oil is added, and the mixture is stirred at 60℃ and 30 rpm for 30 minutes. Then, it is centrifuged in a disc centrifuge at 4800 r / min to remove water and degumm, thus obtaining pressed strong aroma oil. The flavored rapeseed oil obtained by solid-liquid separation, the pressed aromatic oil obtained by pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 1.

[0090] Example 2 Flavored rapeseed oil is produced using rapeseed and first-grade rapeseed oil as raw materials. Compared with Example 1, the flavored oil production system in this example is equipped with a vacuum pump. The gas phase outlet at the top of the vapor explosion material receiving vessel is connected to the vacuum pump via a pipeline, thereby maintaining a negative pressure inside the vapor explosion material receiving vessel.

[0091] After the rapeseed is crushed to an average particle size of approximately 500 μm, it is conveyed to the feed buffer silo A via the feed auger of the digester. When the material height in the feed buffer silo A reaches the upper limit of the set value (when the filling coefficient of the feed buffer silo A reaches 0.95), first close the exhaust valve V1A and the feed valve V2A at the top of the feed buffer silo A, then open the steam inlet valve V3A to introduce steam into the feed buffer silo A, thereby balancing the steam pressure in the feed buffer silo A and the spiral digester; then open the feed valve V5A and the rotary discharge valve V4A on the feed buffer silo A to add the oilseeds from the feed buffer silo A into the spiral digester; while adding material to the spiral digester through the feed buffer silo A, oilseeds are added to the feed buffer silo B via the feed auger of the digester using the same feeding method as the feed buffer silo A. When the material height in feed buffer bin B reaches the set upper limit (when the filling coefficient of feed buffer bin B reaches 0.95), stop the feed auger of the cooker, and close the exhaust valve V1B and feed valve V2B of feed bin B. When the material in feed buffer bin A of the cooker is nearly emptied (when the filling coefficient of feed buffer bin A drops to 0.05), open V3B to achieve pressure connection between feed buffer bin B and the spiral cooker. Then, open V4B and V5B in sequence, close V4A, V5A and V3A, and open V1A, V2A and the feed auger of the cooker. This switches the feeding of the spiral cooker from feed buffer bin A to feed buffer bin B, and at the same time starts to load material into feed buffer bin A of the cooker. This cycle is repeated. By switching between the two feed buffer bins, continuous feeding into the spiral cooker is achieved.

[0092] By adjusting the pressure reducing valve on the steam inlet pipeline of the spiral digester, the pressure of saturated steam in the inner cavity and heating jacket of the spiral digester is maintained at 0.5 MPa. The rotational speed of the spiral digester's spiral shaft is adjusted via a frequency converter, ensuring that the oil, after entering the digester, is discharged into the spiral digester's discharge buffer chamber after approximately 150 seconds. Then, it is sprayed into the explosive material receiving vessel via a discharge auger installed at the bottom of the discharge buffer chamber. The gas phase outlet at the top of the explosive material receiving vessel is connected to the inlet of a water ring vacuum pump via a pipeline. By adjusting the water ring vacuum pump, the absolute pressure inside the explosive material receiving vessel is controlled at 30 kPa. The aroma-generating reaction feedstock oil (first-grade rapeseed oil) is heated to 80°C after heat exchange in a heat recovery heat exchanger and then enters the explosive material receiving vessel to mix with the explosive materials. The mass ratio of primary rapeseed oil injected into the steam-exploded material receiving vessel per hour to rapeseed powder processed by the steam-explosion device per hour is controlled at 5:1. Heating steam is injected into the external coil of the steam-exploded material receiving vessel to maintain the temperature of the mixture (exploded rapeseed powder and primary rapeseed oil) at 108℃. The average residence time of the mixture in the steam-exploded material receiving vessel is controlled at 60 minutes. Water vapor and volatile organic compounds such as flavor substances generated during the spraying and heating process are discharged from the exhaust port at the top of the steam-exploded material receiving vessel and enter the water ring vacuum pump through pipelines. Water vapor and water-soluble volatile organic compounds are absorbed by the working medium (circulating water) of the water ring vacuum pump and become liquid, which is then discharged from the overflow pipeline of the gas-liquid separator. Water-insoluble vacuum pump exhaust gas is discharged from the exhaust pipeline of the gas-liquid separator. When the material is discharged from the steam-exploded material receiving vessel after steam explosion and dehydration, its moisture content is reduced to 0.9 wt%.

[0093] The mixture in the steam-exploded material receiving vessel is continuously pumped to the extraction vessel for aroma generation via a discharge pump. The temperature of the material in the extraction vessel is maintained at 145℃ by adjusting the flow rate of the heating steam injected into the external coil of the extraction vessel; and the average residence time of the mixture in the extraction vessel is controlled to 90 minutes by controlling the material level.

[0094] The mixture in the extraction vessel is pumped to the inner tube of the serpentine heat exchanger by the discharge pump of the extraction vessel. It exchanges heat with the aroma-producing raw material oil injected into the outer tube of the heat exchanger. After the mixture is cooled by heat exchange, it enters the cooling vessel and exchanges heat with the circulating cooling water in the jacket of the vessel. The temperature of the material in the cooling vessel is maintained at 50°C by adjusting the flow rate of the circulating cooling water. After the cooled material is discharged from the bottom of the cooling vessel, it is first separated into solid and liquid by a horizontal screw centrifuge at a speed of 3100 r / min to obtain the supernatant and flavor oil.

[0095] The supernatant obtained is then filtered sequentially through a leaf filter and a precision bag filter to obtain flavored rapeseed oil. The flavored oilseeds discharged from the horizontal screw centrifuge are pressed through a screw press to obtain pressed crude oil and press cake. After filtering the pressed crude oil to remove residue, 2% pure water by weight of the crude oil is added, and the mixture is stirred at 60℃ and 30 rpm for 30 minutes. Then, it is centrifuged in a disc centrifuge at 4800 rpm to remove water and degumm, thus obtaining pressed strong aroma oil.

[0096] The flavored rapeseed oil obtained by solid-liquid separation, the pressed aromatic oil obtained by pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 1.

[0097] Example 3 Flavored rapeseed oil is produced using rapeseed and first-grade rapeseed oil as raw materials. Compared with Example 1, the flavored oil production system of this example adds an oil ring vacuum pump as a vacuuming device. The gas phase outlet at the top of the vapor explosion material receiving vessel is connected to the vacuuming device through a pipeline, and the vacuuming device maintains a negative pressure inside the vapor explosion material receiving vessel. In addition, this example also includes a flavor substance absorption device, which absorbs the flavor substances generated by the oil during vapor explosion and vacuum dehydration in the oil ring vacuum pump and flavor substance absorption tower to produce flavor-absorbed oil, thereby increasing the yield of flavored oil.

[0098] After the rapeseed is crushed to an average particle size of approximately 600 μm, it is conveyed to the feed buffer silo A via the feed auger of the digester. When the material height in the feed buffer silo A reaches the upper limit of the set value (when the filling coefficient of the feed buffer silo A reaches 0.95), first close the exhaust valve V1A and feed valve V2A at the top of the feed buffer silo A, then open the steam inlet valve V3A to introduce steam into the feed buffer silo A, thereby balancing the steam pressure in the feed buffer silo A and the spiral digester; then open the feed valve V5A and the rotary discharge valve V4A on the feed buffer silo A to add the oilseeds from the feed buffer silo A into the spiral digester; while adding material to the spiral digester through the feed buffer silo A, oilseeds are added to the feed buffer silo B via the feed auger of the digester using the same feeding method as the feed buffer silo A. When the material height in feed buffer bin B reaches the set upper limit (when the filling coefficient of feed buffer bin B reaches 0.95), stop the feed auger of the cooker, and close the exhaust valve V1B and feed valve V2B of feed bin B. When the material in feed buffer bin A of the cooker is nearly emptied (when the filling coefficient of feed buffer bin A drops to 0.05), open V3B to achieve pressure connection between feed buffer bin B and the spiral cooker. Then, open V4B and V5B in sequence, close V4A, V5A and V3A, and open V1A, V2A and the feed auger of the cooker. This switches the feeding of the spiral cooker from feed buffer bin A to feed buffer bin B, and at the same time starts to load material into feed buffer bin A of the cooker. This cycle is repeated. By switching between the two feed buffer bins, continuous feeding into the spiral cooker is achieved.

[0099] By adjusting the pressure reducing valve on the steam inlet pipeline of the spiral cooker, the pressure of saturated steam in the inner cavity and heating jacket of the spiral cooker is maintained at 0.7 MPa. The rotational speed of the spiral cooker's spiral shaft is adjusted via a frequency converter, ensuring that the oil reaches the discharge port approximately 120 seconds after entering the cooker, and is then sprayed into the steam-explosion material receiving vessel via a pulse switching valve. The aroma-generating reaction feedstock oil (first-grade rapeseed oil) is heated to 89°C after heat exchange in a heat recovery heat exchanger, and then enters the steam-explosion material receiving vessel to mix with the steam-explosion material. Steam-explosion material is injected hourly. The mass ratio of primary rapeseed oil to rapeseed powder in the material receiving vessel is 3:1. Heating steam is injected into the external coil of the steam-explosion material receiving vessel to maintain the temperature of the mixture (steam-exploded rapeseed powder and primary rapeseed oil) in the steam-explosion material receiving vessel at 98℃. The average residence time of the mixture in the steam-explosion material receiving vessel is controlled at 45 minutes. The water vapor and volatile organic compounds such as flavor substances generated by the material during the steam explosion and heating process are discharged from the exhaust port at the top of the steam-explosion material receiving vessel and enter the air inlet of the oil ring vacuum pump through the pipeline. By adjusting the oil ring vacuum pump, the absolute pressure inside the gas explosion material receiving vessel is controlled at 50 kPa. Another stream of primary rapeseed oil is continuously injected into the oil-gas separator of the oil ring vacuum pump (the mass ratio of primary rapeseed oil injected into the oil-gas separator per hour to the mass of rapeseed powder processed by the gas explosion device per hour is 1.5:1). Water vapor and flavor substances extracted from the gas explosion material receiving vessel mix with the primary rapeseed oil from the oil-gas separator in the oil ring vacuum pump. Some of the water vapor and flavor substances are condensed and absorbed by the primary rapeseed oil, while the unabsorbed water vapor and flavor substances are separated in the oil-gas separator of the oil ring vacuum pump. After gas-liquid separation, the primary rapeseed oil in the separator enters the lower part of the absorption tower bottom through pipeline. The primary rapeseed oil injected into the oil-gas separator overflows into the flavor absorption tower bottom, and is then pumped to the top of the absorption tower by the absorption tower circulation pump. It is then sprayed onto the packing material of the absorption tower by a distributor, where it comes into countercurrent contact with the gaseous flavor substances and water vapor entering from the bottom of the absorption tower. Most of the flavor substances are absorbed by the oil phase, while some of the water vapor condenses on the packing surface into liquid water, which falls into the tower bottom along with the oil phase. The uncondensed and unabsorbed gas is discharged into the atmosphere through the exhaust pipe at the top of the absorption tower. Because the liquid water formed after steam condensation is immiscible and there is a density difference between the two, the oil phase and water phase that have absorbed the flavor substances in the absorption tower bottom can be separated by allowing them to settle and separate in the bottom of the absorption tower. The settled water is then periodically discharged to a wastewater treatment plant through a water separator installed in the bottom of the tower. A stream of water is led out from the outlet pipeline of the absorption tower circulation pump and transported to a precision filter for filtration, and then used as the flavor absorption oil discharge system. By controlling the flow rate of the discharged flavor absorption oil, the liquid level in the absorber of the absorption tower is kept stable. When the material is discharged from the steam explosion material receiving vessel after steam explosion and dehydration, its moisture content is reduced to 1.6 wt%.

[0100] The mixture in the steam-exploded material receiving vessel is continuously pumped to the extraction vessel for aroma generation via a discharge pump. The temperature of the material in the extraction vessel is maintained at 170℃ by adjusting the flow rate of the heating steam injected into the external coil of the extraction vessel; and the average residence time of the mixture in the extraction vessel is controlled to 60 minutes by controlling the material level.

[0101] The mixture in the extraction vessel is pumped to the inner tube of the serpentine heat exchanger by the discharge pump of the extraction vessel. It exchanges heat with the aroma-producing raw material oil injected into the outer tube of the heat exchanger. After the mixture is cooled by heat exchange, it enters the cooling vessel and exchanges heat with the circulating cooling water in the jacket of the vessel. The temperature of the material in the cooling vessel is maintained at 50°C by adjusting the flow rate of the circulating cooling water. After the cooled material is discharged from the bottom of the cooling vessel, it is first separated into solid and liquid by a horizontal screw centrifuge at a speed of 3100 r / min to obtain the supernatant and flavor oil.

[0102] The supernatant obtained is then filtered sequentially through a leaf filter and a precision bag filter to obtain flavored rapeseed oil. The flavored oilseeds discharged from the horizontal screw centrifuge are pressed through a screw press to obtain pressed crude oil and press cake. After filtering the pressed crude oil to remove residue, 2% pure water by weight of the crude oil is added, and the mixture is stirred at 60℃ and 30 rpm for 30 minutes. Then, it is centrifuged in a disc centrifuge at 4800 rpm to remove water and degumm, thus obtaining pressed strong aroma oil.

[0103] The flavored rapeseed oil obtained by solid-liquid separation, the pressed aromatic oil obtained by pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 1.

[0104] Example 4 Flavored peanut oil was prepared using peanut kernels and first-grade peanut oil as raw materials, following the method of Example 3. The difference was that in Example 4, the average particle size of the peanut kernel powder was about 500 μm, the saturated steam pressure in the spiral cooker was 0.9 MPa (gauge pressure), and the residence time of the material in the spiral cooker was 120 s; the reaction temperature in the extraction vessel was 180 °C, and the time maintained at this temperature was 90 min; the mass ratio of first-grade peanut oil to peanut kernel powder injected into the steam-explosion material receiving vessel per hour was 4:1, and the mass ratio of first-grade peanut oil injected into the oil-gas separator per hour to peanut kernel powder added to the steam-explosion material receiving vessel was 2:1. Other operating procedures and process parameters were the same as in Example 3. The flavored peanut oil obtained through solid-liquid separation, the vapor-exploded flavored oil extracted from the absorption tower, the pressed strong-aroma peanut oil obtained through pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 1.

[0105] Example 5 Flavored sunflower seed oil was prepared using sunflower kernels and first-grade sunflower seed oil as raw materials, following the method of Example 3. The difference was that in Example 5, the particle size of the sunflower kernels was approximately 400 μm, the saturated steam pressure in the spiral cooker was 0.4 MPa (gauge pressure), and the residence time of the material in the spiral cooker was 150 s; the reaction temperature in the extraction vessel was 145 °C, and the time at which this temperature was maintained was 75 min; the mass ratio of first-grade sunflower seed oil to sunflower kernel powder injected into the steam-explosion material receiving vessel per hour was 4:1, and the mass ratio of first-grade sunflower seed oil injected into the oil-gas separator per hour to sunflower seed powder added to the steam-explosion material receiving vessel was 1:1. Other operating procedures and process parameters were the same as in Example 3. The flavored sunflower seed oil obtained through solid-liquid separation, the vapor-exploded flavor-absorbing oil extracted from the absorption tower, the pressed strong-aroma sunflower seed oil obtained through pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 2.

[0106] Example 6 Flavored camellia oil was prepared using dehulled camellia seeds and first-grade camellia oil as raw materials, following the method of Example 3. The difference was that in Example 6, the particle size of the dehulled camellia seeds was approximately 600 μm, the saturated steam pressure in the spiral cooker was 1.0 MPa (gauge pressure), and the residence time of the material in the spiral cooker was 90 s; the reaction temperature in the extraction vessel was 185 °C, and the time at which this temperature was maintained was 90 min; the mass ratio of first-grade camellia oil injected into the steam-exploded material receiving vessel per hour to the dehulled camellia seed powder was 4:1, and the mass ratio of first-grade camellia oil injected into the oil-gas separator per hour to the dehulled camellia seed powder added to the steam-exploded material receiving vessel was 2:1. Other operating procedures and process parameters were the same as in Example 3. The flavored camellia oil obtained through solid-liquid separation, the vapor-exploded flavored oil extracted from the absorption tower, the pressed strong-aroma camellia oil obtained through pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 2.

[0107] Example 7 Flavored flaxseed oil was prepared using flaxseed and Grade 1 flaxseed oil as raw materials, following the method of Example 3. The difference was that in Example 7, the flaxseed was pulverized to a particle size of approximately 400 μm, the saturated steam pressure in the spiral cooker was 1.2 MPa (gauge pressure), and the residence time of the material in the spiral cooker was 75 s; the reaction temperature in the extraction vessel was 170 °C, and the time at which this temperature was maintained was 90 min; the mass ratio of Grade 1 flaxseed oil to flaxseed powder injected into the steam-explosion material receiving vessel per hour was 4:1, and the mass ratio of Grade 1 flaxseed oil injected into the oil-gas separator per hour to the flaxseed powder added to the steam-explosion material receiving vessel was 1:1. Other operating procedures and process parameters were the same as in Example 3. The flavored flaxseed oil obtained through solid-liquid separation, the vapor-exploded flavor-absorbing oil extracted from the absorption tower, the pressed aromatic flaxseed oil obtained through pressing flavor oilseeds, and the press cake were analyzed and tested or evaluated for flavor. The results are listed in Table 2.

[0108] Example 8 Flavored flaxseed oil was prepared using flaxseed and Grade 1 flaxseed oil as raw materials, following the method of Example 7. The difference was that the flaxseed in Example 8 was whole, unprocessed seed. Other operating procedures and process parameters were the same as in Example 7. The flavored flaxseed oil obtained through solid-liquid separation, the vapor-exploded flavor-absorbing oil extracted from the absorption tower, the pressed aromatic flaxseed oil obtained through pressing flavor oilseeds, and the press cake were analyzed, tested, or evaluated for flavor. The results are listed in Table 3.

[0109] Example 9 Flavored rapeseed oil was prepared using rapeseed and first-grade rapeseed oil as raw materials, according to the method of Example 3. The difference was that the saturated steam pressure in the spiral cooker in Example 9 was 0.2 MPa (gauge pressure), the residence time of the material in the spiral cooker was 300 s, and the other operation process and process parameters were the same as in Example 3. The flavored rapeseed oil obtained through solid-liquid separation, the vapor-exploded flavored oil extracted from the absorption tower, the pressed fragrant rapeseed oil obtained through pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 3.

[0110] Example 10 The method is the same as in Example 3, except that the dehydration temperature is 80°C, and the moisture content of the material is reduced to 2.4 wt% when it is discharged from the steam explosion material receiving vessel after steam explosion and dehydration. Other operating procedures and process parameters are the same as in Example 3. The flavored rapeseed oil obtained through solid-liquid separation, the vapor-exploded flavored oil extracted from the absorption tower, the pressed fragrant rapeseed oil obtained through pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 3.

[0111] Example 11 Flavored sunflower seed oil was prepared according to the method of Example 5, except that the aroma-generating temperature was 120°C, while other operating procedures and process parameters were the same as in Example 5. The flavored sunflower seed oil obtained through solid-liquid separation, the vapor-exploded flavor-absorbing oil extracted from the absorption tower, the pressed strong-aroma sunflower seed oil obtained through pressing flavored oilseeds, and the pressed cake were analyzed, tested, or evaluated for flavor. The results are listed in Table 3.

[0112] Example 12 The method of Example 3 is the same as that of Example 3, except that the mass ratio of oilseed to raw oil is 1:2.4, and the other operating procedures and process parameters are the same. The flavored rapeseed oil obtained through solid-liquid separation, the vapor-exploded flavored oil extracted from the absorption tower, the pressed fragrant rapeseed oil obtained through pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 3.

[0113] Example 13 The method of Example 3 is the same as that of Example 3, except that the mass ratio of flavor absorption raw oil to oilseed is 4:1, and the obtained flavor absorption oil is used directly for flavor evaluation without dilution. Other operating procedures and process parameters are the same as those of Example 3. The flavored rapeseed oil obtained through solid-liquid separation, the vapor-exploded flavored oil extracted from the absorption tower, the pressed fragrant rapeseed oil obtained through pressing flavored oilseeds, and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 3.

[0114] Comparative Example 1 The method of Example 1 is different in that the crushed rapeseed is not steamed or steam-exploded, but directly mixed with first-grade rapeseed oil for extraction, cooling and solid-liquid separation. The operation process and process parameters of extraction, cooling and solid-liquid separation are the same as those of Example 1. Nutritional composition analysis or flavor evaluation were performed on flavored rapeseed oil obtained by solid-liquid separation, pressed fragrant rapeseed oil obtained by pressing flavored oilseeds, and rapeseed cake. The results are listed in Table 1.

[0115] Comparative Example 2 The method of Example 4 is different in that the crushed peanut kernels are not steamed or steam-exploded, but directly mixed with first-grade peanut oil for extraction, cooling and solid-liquid separation. The operation process and process parameters of extraction, cooling and solid-liquid separation are the same as those of Example 4. The obtained flavored peanut oil, flavor-absorbed oil, pressed fragrant peanut oil, and press cake were analyzed and tested or evaluated for flavor. The results are listed in Table 1.

[0116] Comparative Example 3 The method of Example 5 differs in that the crushed sunflower seeds are not steamed or steam-exploded, but are directly mixed with first-grade sunflower seed oil for extraction, cooling and solid-liquid separation. The operation process and process parameters of extraction, cooling and solid-liquid separation are the same as those of Example 5. The obtained flavored sunflower seed oil, flavor-absorbed oil, pressed fragrant sunflower seed oil, and press cake were analyzed and tested or evaluated for flavor. The results are listed in Table 2.

[0117] Comparative Example 4 The method of Example 6 is different in that the crushed sunflower seeds are not steamed or steam-exploded, but the crushed shelled camellia seed powder and first-grade camellia oil are directly mixed for extraction, cooling and solid-liquid separation. The operation process and process parameters of extraction, cooling and solid-liquid separation are the same as those of Example 6. The obtained flavored camellia oil, flavor-absorbed oil, pressed strong-aroma camellia oil, and press cake were analyzed and tested or evaluated for flavor. The results are listed in Table 2.

[0118] Comparative Example 5 The method of Example 7 is different in that the pulverized flaxseed is not steamed or steam-exploded, but the pulverized flaxseed powder and first-grade flaxseed oil are directly mixed for extraction, cooling and solid-liquid separation. The operation process and process parameters of extraction, cooling and solid-liquid separation are the same as those of Example 7. The obtained flavored flaxseed oil, flavor-absorbed oil, pressed aromatic flaxseed oil, and press cake were analyzed and tested or evaluated for flavor. The results are listed in Table 2.

[0119] Comparative Example 6 The method of Example 3 differs in that, in Comparative Example 6, the material is steamed and then sprayed into an atmospheric pressure container for steam explosion. The oilseed after steam explosion is not added with raw material oil for aroma generation. Instead, it is dried until the moisture content is the same as that of the rapeseed raw material (12.8%) and then fed into a screw oil press for pressing to obtain pressed crude oil and press cake. After filtering the pressed crude oil to remove residue, 2% of pure water by weight of crude oil is added, and the mixture is stirred at 60°C and 30 rpm for 30 minutes. Then, it is centrifuged and dehydrated using a disc centrifuge at 4800 r / min to obtain pressed fragrant rapeseed oil and press cake.

[0120] The obtained pressed fragrant rapeseed oil and the pressed cake were analyzed and tested or evaluated for flavor. The results are listed in Table 2.

[0121] Table 1

[0122] Table 2

[0123] Table 3

[0124] As can be seen from the data in Tables 1-3, comparing Examples 1-7 with Examples 8-13 and Comparative Examples 1-6, it is evident that in the preferred embodiment of this invention, the cooked oilseeds are subjected to steam explosion and dehydration under vacuum conditions, further reducing the acid value and moisture content of the flavor oil obtained after the aroma-enhancing reaction, improving flavor appeal, and further increasing the content of vitamin E and sterols. Simultaneously, the oil content of the resulting cake is significantly reduced. In a more preferred embodiment of this invention, the oilseeds undergo steam explosion, dehydration, and aroma enhancement treatments, while using first-grade edible oil as the working medium of the oil ring vacuum pump in the vacuum equipment and the absorption medium for the steam-exploded flavor substances. This not only yields flavor oils and pressed aromatic oils with lower acid value and moisture content, higher flavor appeal and flavor intensity, but also flavor-absorbing oils with flavor intensity and flavor appeal essentially equivalent to the flavor oils. This improves the utilization efficiency of flavor substances in the oilseeds and reduces the emission of air pollutants.

[0125] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a flavored oil, characterized in that, The method includes: steaming the oil under positive pressure to cause steam explosion in the steam-exploded material, and then mixing the steam-exploded material with the raw oil and performing dehydration, aroma generation, cooling and solid-liquid separation in sequence.

2. The method according to claim 1, wherein, The method also includes pulverizing the oilseeds before cooking; Preferably, the pulverization conditions are such that the average particle size of the pulverized material is no greater than 600 μm; And / or, the cooking is carried out in a spiral cooker, and the mixture of the steam-exploded material and the raw material oil is carried out in a steam-exploded material receiving vessel. The mixing method includes: the cooked material is sprayed from the discharge buffer chamber into the steam-exploded material receiving vessel, and mixed with the raw material oil that has been preheated by a heat recovery heat exchanger in a batching vessel. Preferably, the mass ratio of the oilseed to the raw oil is 1:(2.5-10), and more preferably 1:(3-5).

3. The method according to claim 1 or 2, wherein, The positive pressure condition results in a steam pressure of 0.2-1.6 MPa within the cooking system; And / or, the steam explosion occurs in a steam explosion material receiving vessel, and the steam explosion occurs in the instant that the cooked material is sprayed into the steam explosion material receiving vessel from below the outlet of the spiral cooker; And / or, the cooking conditions include: material temperature of 120-205℃ and time of 20-240s; And / or, the mode of steam explosion is selected from atmospheric pressure steam explosion and / or negative pressure steam explosion, preferably negative pressure steam explosion; Preferably, the negative pressure steam explosion condition is such that the absolute pressure inside the steam explosion material receiving vessel is 0.02-0.08 MPa.

4. The method according to any one of claims 1-3, wherein, The dehydration is carried out in a steam-exploded material receiving vessel, and the dehydration conditions are such that the moisture content of the dehydrated mixture is 0.5wt%-2wt%, preferably 1wt%-2wt%, and more preferably 1.2wt%-1.8wt%. And / or, the dehydration conditions include: a temperature of 85-125°C and a time of 20-60 min; And / or, the dehydration method is selected from atmospheric pressure dehydration and / or negative pressure dehydration, preferably negative pressure dehydration; Preferably, the negative pressure dehydration conditions result in an absolute pressure of 0.02-0.08 MPa inside the steam-exploded material receiving vessel.

5. The method according to any one of claims 1-4, wherein, The aroma generation process is carried out in an extraction vessel; the conditions for aroma generation include: a temperature of 125-210℃ and a time of 20-180 min. And / or, the cooling is carried out in a cooling kettle; the cooling conditions are such that the temperature of the mixture after aroma generation does not exceed 90°C, preferably 35-65°C; And / or, the solid-liquid separation method is selected from centrifugation and / or filtration, preferably centrifugation and filtration.

6. The method according to any one of claims 1-5, wherein, The oilseed is selected from at least one of rapeseed, peanut kernels, sunflower kernels, camellia seeds, flaxseed, corn germ, walnuts and sesame seeds; Preferably, the method further includes using flavor-absorbing raw oil as a medium to absorb flavor substances generated during the steam explosion process to obtain flavor-absorbing oil; More preferably, the raw material oil and the flavor-absorbing raw material oil are each independently selected from first- or second-grade edible vegetable oils.

7. The method according to claim 6, wherein, The method for absorbing flavor substances generated during the steam explosion process includes: connecting the exhaust port at the top of the steam explosion material receiving vessel to an oil ring vacuum pump via a pipeline, then injecting the flavor absorption raw material oil into the oil-gas separator of the oil ring vacuum pump, and mixing the water vapor and flavor substances extracted from the steam explosion material receiving vessel with the flavor absorption raw material oil from the oil-gas separator in the oil ring vacuum pump. Preferably, the mass ratio of the flavor-absorbing raw material oil to the oilseed is (1.5-3):

1.

8. The method according to claim 3, wherein, A discharge buffer chamber is provided below the discharge port of the spiral cooker, and the lower part of the discharge buffer chamber is connected to the steam explosion material receiving vessel. Alternatively, a discharge buffer chamber is provided below the discharge port of the spiral cooker, and a discharge auger is provided at the lower part of the discharge buffer chamber. The discharge port of the discharge auger is connected to the steam explosion material receiving vessel. And / or, the feed inlet of the spiral cooker is connected to feed buffer chamber A and feed buffer chamber B respectively through the discharge pipe; the feed inlets of feed buffer chamber A and feed buffer chamber B are connected to the discharge outlet of the cooker feed auger respectively through the feed pipe. Preferably, the discharge buffer hopper is equipped with a material level detector and a pulse switching valve.

9. The method according to claim 8, wherein, The feed pipes connecting the feed auger of the cooker to the feed buffer chamber A and the feed buffer chamber B are respectively equipped with feed valves V2A and V2B. And / or, rotary discharge valves V4A and V4B are respectively installed at the discharge ports of the feed buffer chamber A and feed buffer chamber B; feed valves V5A and V5B are respectively installed on the discharge pipes connecting the feed buffer chamber A and feed buffer chamber B to the spiral cooker.

10. The method according to claim 8 or 9, wherein, The top of the feed buffer silo A is respectively equipped with an exhaust valve V1A and a steam valve V3A; And / or, the top of the feed buffer chamber B is respectively provided with an exhaust valve V1B and a steam valve V3B.

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