A method for the extraction of rapeseed oil with high retention of active ingredients

Abstract

The application belongs to the technical field of producing fat oil from raw materials, and particularly relates to a rapeseed oil extraction method with high retention of active ingredients. The rapeseed oil extraction method with high retention of active ingredients comprises the following steps: S1, performing enzyme pretreatment on rapeseed to obtain enzyme pretreated rapeseed; S2, performing subcritical extraction treatment on the enzyme pretreated rapeseed to obtain crude rapeseed oil; and S3, performing degumming treatment on the crude rapeseed oil to obtain rapeseed oil with high retention of active ingredients. Through improvement of the preparation process, the rapeseed oil with high retention of active ingredients is realized, and the content of oleic acid and phytosterol in the rapeseed oil is effectively improved.

Description

Technical Field

[0001] This invention belongs to the technical field of producing oils from raw materials, specifically relating to a method for extracting rapeseed oil with high retention of active ingredients. Background Technology

[0002] Rapeseed is my country's largest oilseed crop, and rapeseed oil plays a crucial role in the country's edible vegetable oil supply. Rapeseed oil provides the human body with two main categories of nutrients: fatty acids and fat-soluble nutrients. The main fatty acids in rapeseed oil include oleic acid, linoleic acid, and linolenic acid, with a balanced composition suitable for human nutritional needs. It is an important source of fat-soluble nutrients such as polyphenols, phytosterols, vitamin E, and carotenoids, all of which play vital roles in human health. Rapeseed oil is a high-quality, affordable, and healthy edible vegetable oil. It has a rich and mellow aroma and high nutritional value, primarily due to the high content of various fatty acids such as oleic acid, linolenic acid, and erucic acid.

[0003] High-oleic rapeseed oil boasts high nutritional value and good thermal stability, exhibiting excellent oxidative stability even at high temperatures, making it ideal for home cooking and foods requiring long shelf life. Due to its low polyunsaturated fatty acid content, high-oleic rapeseed oil can meet the processing requirements of certain foods without hydrogenation, thus avoiding the formation of harmful trans fatty acids. Furthermore, it possesses similar thermal stability to animal fats rich in saturated fatty acids. During oil oxidation, high-oleic rapeseed oil provides chain-blocking antioxidants, acting at the initial stage of the reaction. Combined with polyphenols and phytosterols, it effectively slows down oxidation; these substances not only possess important physiological activities but also provide extremely high nutritional value.

[0004] Chinese patent (publication number CN119752528A) discloses a production process and product for fragrant rapeseed oil. The production process includes a seed roasting unit, a pressing unit, and a degumming unit. In the seed roasting unit, the roasting temperature is 70–90°C. In the degumming unit, the degumming method is either hydration degumming or adsorption degumming, with the hydration degumming temperature being 60–80°C. The adsorption degumming uses citric acid and silica as the adsorbent materials. The fragrant rapeseed oil obtained using this process has a better color, richer flavor, and more nutrients, making it popular with consumers. However, this patented technology affects the properties of some active components, such as oleic acid and phytosterols, during the roasting process, resulting in a decrease in the content of active ingredients in the final rapeseed oil.

[0005] Therefore, there is an urgent need for a rapeseed oil extraction method that, through improvements in the preparation process, can achieve the goal of high retention of active ingredients and effectively increase the oleic acid and phytosterol content of rapeseed oil. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a method for extracting rapeseed oil with high retention of active ingredients. The present invention first uses alkaline protease and cellulase to perform enzymatic pretreatment on rapeseed, then performs subcritical extraction on the enzymatically pretreated rapeseed to obtain crude rapeseed oil, and finally performs enzymatic degumming treatment under ultrasonic conditions to obtain rapeseed oil with high retention of active ingredients. By combining multiple physical processing techniques, the content of oleic acid and phytosterols in rapeseed oil is increased.

[0007] This invention provides a method for extracting rapeseed oil with high retention of active ingredients, comprising the following steps: S1. Enzymatic pretreatment of rapeseed is carried out to obtain enzymatically pretreated rapeseed. S2. The enzymatically pretreated rapeseed is subjected to subcritical extraction to obtain crude rapeseed oil. S3. Degumming is performed on the crude rapeseed oil to obtain rapeseed oil with high retention of active ingredients.

[0008] As a preferred technical solution of the present invention, the enzymatic pretreatment in step S1 is as follows: rapeseed is added to distilled water to absorb water and swell, crushed and then added to a compound enzyme solution for pretreatment to obtain enzymatically pretreated rapeseed.

[0009] As a preferred technical solution of the present invention, the specific steps of the enzymatic pretreatment in step S1 are as follows: by weight, 400-500 parts of rapeseed are added to 600-800 parts of distilled water, heated to 40-50℃ and soaked for 2-4 hours to absorb water and swell, crushed and then added to 600-800 parts of compound enzyme solution and mixed evenly, pretreated at 40-50℃ for 4-6 hours, enzyme inactivated at 84-86℃ for 8-10 minutes, and dried to obtain enzymatically pretreated rapeseed.

[0010] As a preferred embodiment of the present invention, the weight of the rapeseed can be 400 parts, 420 parts, 440 parts, 460 parts, 480 parts, or 500 parts, etc.

[0011] As a preferred embodiment of the present invention, the weight fraction of the composite enzyme solution can be 600 parts, 650 parts, 700 parts, 750 parts, or 800 parts, etc.

[0012] As a preferred technical solution of the present invention, the preparation steps of the composite enzyme solution are as follows: by weight, 18-22 parts of alkaline protease and 8-12 parts of cellulase are added to 900-1000 parts of distilled water and fully dissolved, and the pH is adjusted to 5.8-6.2 to obtain the composite enzyme solution.

[0013] As a preferred embodiment of the present invention, the weight fraction of the alkaline protease may be 18, 19, 20, 21, or 22 parts, etc.

[0014] As a preferred embodiment of the present invention, the weight fraction of the cellulase may be 8, 9, 10, 11 or 12 parts, etc.

[0015] This invention involves crushing soaked and swollen rapeseed to increase the contact area for subsequent enzymatic pretreatment. During the pretreatment process, alkaline protease is responsible for hydrolyzing proteins, and cellulase is responsible for degrading cellulose in the cell wall. The material is then dried to obtain the final enzymatically pretreated rapeseed for use in subsequent processes.

[0016] As a preferred technical solution of the present invention, the specific steps of the subcritical extraction process in step S2 are as follows: the rapeseed pretreated by enzyme is crushed and sieved, then transferred to a filter bag, and subcritical extraction is performed using butane as a solvent, followed by flash evaporation under reduced pressure to obtain crude rapeseed oil.

[0017] As a preferred embodiment of the present invention, the mesh size of the sieve is 60-100 mesh.

[0018] As a preferred embodiment of the present invention, the subcritical extraction conditions are: pressure of 0.3~0.5MPa, temperature of 44~46℃, time of 30~40min / cycle, and material-to-liquid ratio of 1:(8~10).

[0019] In the processing of this invention, rapeseed is first pre-treated with enzymes and then crushed to further reduce the particle size. Large impurities are removed by sieving to ensure uniform particle size. Then, butane is used for subcritical extraction. Butane penetrates into the pores of the material to dissolve the oil and form a mixed oil. Finally, the solvent is removed by vacuum flash evaporation using the low boiling point of butane to obtain crude rapeseed oil.

[0020] As a preferred technical solution of the present invention, the degumming process in step S3 is as follows: rapeseed crude oil and citric acid solution are mixed and homogenized, then phospholipase C is added and transferred to an ultrasonic cleaner for ultrasonic enzymatic degumming to obtain rapeseed oil with high retention of active ingredients.

[0021] As a preferred technical solution of the present invention, the specific steps of the degumming treatment in step S3 are as follows: by weight, 400-500 parts of crude rapeseed oil and 0.4-0.6 parts of 50% citric acid solution are mixed at 60-70°C, homogenized at 8000-10000 r / min for 1-3 min, and then stirred at 70-72°C for 30-40 min; after cooling to 50-55°C, 0.6-0.8 parts of 15% sodium hydroxide solution, 0.1-0.2 parts of phospholipase C and 10-12 parts of distilled water are added, and the mixture is transferred to an ultrasonic cleaner for ultrasonic enzymatic degumming. After degumming, the temperature is raised to 84-86°C to inactivate the enzyme for 8-10 min, and then centrifuged.

[0022] As a preferred embodiment of the present invention, the crude rapeseed oil may be in the following weight proportions: 400 parts, 420 parts, 440 parts, 460 parts, 480 parts, or 500 parts, etc.

[0023] As a preferred embodiment of the present invention, the citric acid solution may be in the form of 0.4 parts, 0.5 parts, or 0.6 parts by weight.

[0024] As a preferred embodiment of the present invention, the sodium hydroxide solution may be 0.6 parts, 0.7 parts, or 0.8 parts by weight, etc.

[0025] As a preferred embodiment of the present invention, the weight fraction of phospholipase C may be 0.1 parts, 0.12 parts, 0.14 parts, 0.16 parts, 0.18 parts, or 0.2 parts, etc.

[0026] As a preferred technical solution of the present invention, the conditions for ultrasonic enzymatic degumming are: ultrasonic power of 480~500W, temperature of 54~56℃, and time of 20~30min.

[0027] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention forms a combined pressing process by enzymatic pretreatment, subcritical extraction and ultrasonic enzymatic degumming. The enzymatic pretreatment gently breaks the cell wall to improve the extraction efficiency, the subcritical low temperature extraction retains the active ingredients such as oleic acid and phytosterols to the maximum extent, and the ultrasonic enzymatic degumming efficiently removes impurities with minimal loss of activity. The three processes work together to effectively increase the content of active ingredients in rapeseed oil.

[0028] (2) The cell wall of rapeseed is mainly composed of cellulose, hemicellulose and pectin, forming a dense network structure that hinders the release of internal oils and proteins. Cellulase can specifically hydrolyze the cellulose chains in the cell wall, destroying the integrity of the cell wall and exposing the cell contents. After the cell wall is partially destroyed, the proteins that are tightly bound to the oils and the storage proteins in the cell are exposed. Alkaline protease can hydrolyze these proteins into small peptides or amino acids, destroy lipoprotein complexes, reduce the stability of the emulsion, and promote the aggregation and floating of oil droplets. By combining alkaline protease and cellulase for enzymatic pretreatment, the active ingredients of rapeseed can be efficiently preserved.

[0029] (3) In the subcritical extraction process of the present invention, the low temperature of subcritical butane extraction avoids high-temperature oxidation, and unsaturated fatty acids such as oleic acid are completely preserved, reducing oxidation loss during the extraction process and thus increasing the final oleic acid content. Phytosterols are sensitive to heat, and high temperature will cause phytosterols to be oxidized or converted into dehydrated sterols with lower biological activity. Subcritical butane extraction reduces the heat loss of phytosterols through a lower temperature. At the same time, butane has excellent solubility for phytosterols and can efficiently carry the sterols released by enzyme decomposition into the oil phase. The combined effect increases the phytosterol content.

[0030] (4) The ultrasonic enzymatic degumming technology of the present invention removes impurities while minimizing the loss of heat-sensitive and oxidation-sensitive nutrients through mild reaction conditions and efficient mass transfer mechanism, thereby maximizing the retention of the active ingredients originally in crude oil and avoiding their loss during refining, thereby increasing the content of oleic acid and phytosterols in the final rapeseed oil. Detailed Implementation

[0031] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention. Example

[0032] This embodiment provides a method for extracting rapeseed oil with high retention of active ingredients, including the following steps: S1. By weight, 22 parts of alkaline protease and 8 parts of cellulase were added to 1000 parts of distilled water and dissolved thoroughly. The pH was adjusted to 6.2 to obtain a compound enzyme solution. 500 parts of rapeseed were added to 800 parts of distilled water, heated to 50℃ and soaked for 2 hours to absorb water and swell. After crushing, 800 parts of the compound enzyme solution were added and mixed evenly. The mixture was pretreated at 50℃ for 4 hours, the enzyme was inactivated at 86℃ for 8 minutes, and then dried to obtain the enzyme-pretreated rapeseed. S2. After the rapeseed pretreated by enzyme is crushed and sieved (mesh size is 100 mesh), it is transferred to a filter bag and subjected to subcritical extraction with butane as solvent (pressure is 0.5 MPa, temperature is 46℃, time is 40 min / time, material-liquid ratio is 1:10). The crude rapeseed oil is obtained by flash evaporation under reduced pressure. S3. By weight, 500 parts of crude rapeseed oil and 0.6 parts of 50% citric acid solution were mixed at 70℃. The mixture was first homogenized at 10000 r / min for 1 min, and then stirred at 72℃ for 30 min. After cooling to 55℃, 0.8 parts of 15% sodium hydroxide solution, 0.2 parts of phospholipase C and 12 parts of distilled water were added. The mixture was then transferred to an ultrasonic cleaner for ultrasonic enzymatic degumming (ultrasonic power of 500W, temperature of 56℃, time of 30 min). After degumming, the temperature was raised to 86℃ to inactivate the enzyme for 8 min. After centrifugation, rapeseed oil with high retention of active ingredients was obtained. Example

[0033] This embodiment provides a method for extracting rapeseed oil with high retention of active ingredients, including the following steps: S1. By weight, 18 parts of alkaline protease and 12 parts of cellulase were added to 900 parts of distilled water and dissolved thoroughly. The pH was adjusted to 5.8 to obtain a compound enzyme solution. 400 parts of rapeseed were added to 600 parts of distilled water, heated to 40℃ and soaked for 4 hours to absorb water and swell. After crushing, 600 parts of the compound enzyme solution were added and mixed evenly. The mixture was pretreated at 40℃ for 6 hours, the enzyme was inactivated at 84℃ for 10 minutes, and then dried to obtain the enzyme-pretreated rapeseed. S2. After the rapeseed pretreated by enzyme is crushed and sieved (60 mesh), it is transferred to a filter bag and subjected to subcritical extraction with butane as solvent (pressure 0.4 MPa, temperature 44℃, time 30 min / time, material-liquid ratio 1:8). The crude rapeseed oil is obtained by flash evaporation under reduced pressure. S3. By weight, 400 parts of crude rapeseed oil and 0.4 parts of 50% citric acid solution were mixed at 60℃. The mixture was first homogenized at 8000 r / min for 3 min, and then stirred at 70℃ for 40 min. After cooling to 50℃, 0.6 parts of 15% sodium hydroxide solution, 0.1 parts of phospholipase C and 10 parts of distilled water were added. The mixture was then transferred to an ultrasonic cleaner for ultrasonic enzymatic degumming (ultrasonic power of 480W, temperature of 54℃, time of 30 min). After degumming, the temperature was raised to 84℃ to inactivate the enzyme for 10 min. The mixture was then centrifuged to obtain rapeseed oil with high retention of active ingredients. Example

[0034] This embodiment provides a method for extracting rapeseed oil with high retention of active ingredients, including the following steps: S1. By weight, 20 parts of alkaline protease and 10 parts of cellulase were added to 950 parts of distilled water and dissolved thoroughly. The pH was adjusted to 6.0 to obtain a compound enzyme solution. 450 parts of rapeseed were added to 700 parts of distilled water, heated to 45℃ and soaked for 3 hours to absorb water and swell. After crushing, 700 parts of the compound enzyme solution were added and mixed evenly. The mixture was pretreated at 45℃ for 5 hours, the enzyme was inactivated at 85℃ for 9 minutes, and then dried to obtain the enzyme-pretreated rapeseed. S2. After the rapeseed pretreated by enzyme is crushed and sieved (mesh size is 80 mesh), it is transferred to a filter bag and subjected to subcritical extraction with butane as solvent (pressure is 0.3 MPa, temperature is 45℃, time is 35 min / time, material-liquid ratio is 1:9). The crude rapeseed oil is obtained by flash evaporation under reduced pressure. S3. By weight, 450 parts of crude rapeseed oil and 0.5 parts of 50% citric acid solution were mixed at 65℃. The mixture was first homogenized at 9000 r / min for 2 min, and then stirred at 71℃ for 35 min. After cooling to 52℃, 0.7 parts of 15% sodium hydroxide solution, 0.15 parts of phospholipase C and 11 parts of distilled water were added. The mixture was then transferred to an ultrasonic cleaner for ultrasonic enzymatic degumming (ultrasonic power of 490W, temperature of 55℃, time of 25 min). After degumming, the temperature was raised to 85℃ to inactivate the enzyme for 9 min. After centrifugation, rapeseed oil with high retention of active ingredients was obtained.

[0035] Comparative Example 1 The difference between this comparative example and Example 1 is that no enzymatic pretreatment is performed in step S1.

[0036] Comparative Example 2 The difference between this comparative example and Example 1 is that in step S1, the enzyme pretreatment was changed to use 30 portions of alkaline protease to prepare the enzyme solution.

[0037] Comparative Example 3 The difference between this comparative example and Example 1 is that in step S1, the enzyme pretreatment was changed to use 30 portions of cellulase to prepare the enzyme solution.

[0038] Comparative Example 4 The difference between this comparative example and Example 1 is that in step S2, conventional pressing (using a screw press with an internal screw temperature of 60°C and an outlet temperature of 40°C) is used instead of subcritical extraction.

[0039] Comparative Example 5 The difference between this comparative example and Example 1 is that ultrasonic enzymatic degumming is not performed in step S3.

[0040] Performance testing Peroxide value: Tested in accordance with the requirements of GB / T 1536-2021 Rapeseed Oil.

[0041] Fatty acids: The test was conducted according to the chromatographic conditions specified in GB 5009.168-2016 National Food Safety Standard for the Determination of Fatty Acids in Food.

[0042] Phytosterols: Phytosterols were analyzed using GC-MS equipped with FID. The temperature program was as follows: initial column temperature was set to 200℃, held for 0.5 min, increased to 300℃ at a rate of 10℃ / min, and held for 18 min.

[0043] The performance test data above are shown in Table 1.

[0044] Table 1 Performance Test Results Peroxide value (g / 100g) Oleic acid content (%) Phytosterol content (mg / kg) Example 1 0.074 82.1 2047 Example 2 0.081 81.5 2021 Example 3 0.078 81.9 2034 Comparative Example 1 0.095 74.6 1769 Comparative Example 2 0.087 79.8 1945 Comparative Example 3 0.084 79.1 1932 Comparative Example 4 0.089 76.3 1826 Comparative Example 5 0.092 75.5 1781 As can be seen from the above, the present invention forms a combined pressing process through enzymatic pretreatment, subcritical extraction, and ultrasonic enzymatic degumming. The enzymatic pretreatment gently breaks down the cell walls to improve extraction efficiency, the subcritical low-temperature extraction retains the maximum amount of active ingredients such as oleic acid and phytosterols, and the ultrasonic enzymatic degumming efficiently removes impurities with minimal loss of activity. The synergistic effect of the three processes effectively increases the content of active ingredients in rapeseed oil (Examples 1 to 3).

[0045] Compared to Example 1, step S1 did not involve enzymatic pretreatment, thus lacking the effect of enzymatic pretreatment, resulting in a decrease in oleic acid and phytosterol content (Comparative Example 1). Compared to Example 1, step S1 enzymatic pretreatment used 30 parts of alkaline protease to prepare the enzyme solution, lacking the effect of cellulase compounding, leading to poor results, thus decreasing oleic acid and phytosterol content (Comparative Example 2). Compared to Example 1, step S1 enzymatic pretreatment used 30 parts of cellulase to prepare the enzyme solution, lacking the effect of alkaline protease compounding, leading to poor results, thus decreasing oleic acid and phytosterol content (Comparative Example 3). Compared to Example 1, step S2 used ordinary pressing instead of subcritical extraction, lacking the effect of subcritical extraction, thus decreasing oleic acid and phytosterol content (Comparative Example 4). Compared to Example 1, step S3 did not involve ultrasonic enzymatic degumming, lacking the effect of ultrasonic enzymatic degumming, thus decreasing oleic acid and phytosterol content (Comparative Example 5).

Claims

1. A method for extracting rapeseed oil with high retention of active ingredients, characterized in that, Includes the following steps: S1. Enzymatic pretreatment of rapeseed is carried out to obtain enzymatically pretreated rapeseed. S2. The enzymatically pretreated rapeseed is subjected to subcritical extraction to obtain crude rapeseed oil. S3. Degumming is performed on the crude rapeseed oil to obtain rapeseed oil with high retention of active ingredients.

2. The method for extracting rapeseed oil with high retention of active ingredients according to claim 1, characterized in that, The enzymatic pretreatment in step S1 is as follows: rapeseed is added to distilled water to absorb water and swell, then crushed and pretreated with a compound enzyme solution to obtain enzymatically pretreated rapeseed.

3. The method for extracting rapeseed oil with high retention of active ingredients according to claim 1, characterized in that, The specific steps of the enzymatic pretreatment described in step S1 are as follows: by weight, 400-500 parts of rapeseed are added to 600-800 parts of distilled water, heated to 40-50℃ and soaked for 2-4 hours to absorb water and swell. After crushing, 600-800 parts of compound enzyme solution are added and mixed evenly. The mixture is pretreated at 40-50℃ for 4-6 hours, the enzyme is inactivated at 84-86℃ for 8-10 minutes, and then dried to obtain the enzymatically pretreated rapeseed.

4. The method for extracting rapeseed oil with high retention of active ingredients according to claim 3, characterized in that, The preparation steps of the composite enzyme solution are as follows: by weight, 18-22 parts of alkaline protease and 8-12 parts of cellulase are added to 900-1000 parts of distilled water and fully dissolved, and the pH is adjusted to 5.8-6.2 to obtain the composite enzyme solution.

5. The method for extracting rapeseed oil with high retention of active ingredients according to claim 1, characterized in that, The specific steps of the subcritical extraction process described in step S2 are as follows: the rapeseed pretreated by enzyme is crushed and sieved, then transferred to a filter bag, and subcritical extraction is performed using butane as a solvent, followed by flash evaporation under reduced pressure to obtain crude rapeseed oil.

6. The method for extracting rapeseed oil with high retention of active ingredients according to claim 5, characterized in that, The sieve mesh size is 60-100 mesh.

7. The method for extracting rapeseed oil with high retention of active ingredients according to claim 5, characterized in that, The subcritical extraction conditions are: pressure 0.3~0.5MPa, temperature 44~46℃, time 30~40min / cycle, and material-to-liquid ratio 1:(8~10).

8. The method for extracting rapeseed oil with high retention of active ingredients according to claim 1, characterized in that, The degumming process described in step S3 is as follows: rapeseed crude oil and citric acid solution are mixed and homogenized, then phospholipase C is added and the mixture is transferred to an ultrasonic cleaner for ultrasonic enzymatic degumming to obtain rapeseed oil with high retention of active ingredients.

9. The method for extracting rapeseed oil with high retention of active ingredients according to claim 1, characterized in that, The specific steps of the degumming process described in step S3 are as follows: By weight, 400-500 parts of crude rapeseed oil and 0.4-0.6 parts of 50% citric acid solution are mixed at 60-70℃. The mixture is first homogenized at 8000-10000 r / min for 1-3 min, and then stirred at 70-72℃ for 30-40 min. After cooling to 50-55℃, 0.6-0.8 parts of 15% sodium hydroxide solution, 0.1-0.2 parts of phospholipase C, and 10-12 parts of distilled water are added. The mixture is then transferred to an ultrasonic cleaner for ultrasonic enzymatic degumming. After degumming, the temperature is raised to 84-86℃ to inactivate the enzyme for 8-10 min, and then centrifuged.

10. The method for extracting rapeseed oil with high retention of active ingredients according to claim 9, characterized in that, The conditions for ultrasonic enzymatic degumming are: ultrasonic power of 480~500W, temperature of 54~56℃, and time of 20~30min.