Refining method of low-temperature cold-pressed pecan oil
By combining magnetic enzyme carriers and modified decolorizing agents, the problems of phospholipase being difficult to reuse and the mediocre decolorization effect in the traditional low-temperature cold-pressed pecan oil refining process are solved, achieving efficient degumming and decolorization and improving the quality of pecan oil.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HANGZHOU QIANDAOHU YAOJI SPECIALTY CO LTD
- Filing Date
- 2026-03-20
- Publication Date
- 2026-05-15
AI Technical Summary
In the traditional low-temperature cold-pressed pecan oil refining method, phospholipase is difficult to reuse, resulting in high production costs, poor degumming effect, and the effect of using decolorizing agents alone is generally mediocre.
A combination of magnetic enzyme carrier and modified decolorizing agent is used. The magnetic enzyme carrier is modified with silanization to increase functional groups, and the modified decolorizing agent is composed of activated clay and sugar char. This combination is used for the degumming and decolorization of pecan oil.
This approach enables the reusability of magnetic enzyme carriers, improves degumming efficiency, and complements the adsorption properties of modified decolorizing agents, thereby enhancing the decolorization ability of pecan oil and ensuring the quality of the finished oil.
Smart Images
Figure CN122038041A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of walnut oil refining technology, specifically a method for refining low-temperature cold-pressed pecan oil. Background Technology
[0002] Low-temperature cold pressing is a method of extracting oil from pecans that have not been roasted or roasted at a pressing temperature of about 60°C. This method can effectively preserve the nutrients in the oil and ensure the quality and nutritional value of the oil to the greatest extent.
[0003] Cold-pressed pecan oil sometimes requires further refining to improve its quality. To avoid damaging the quality of the finished oil at high temperatures, processes such as degumming and decolorization in the refining process are usually carried out at lower temperatures.
[0004] Traditional enzymatic degumming typically uses phospholipases, which are mild, efficient, and environmentally friendly. However, phospholipases are difficult to reuse, leading to high production costs. Traditional decolorization methods often use adsorbents such as activated clay and biochar, but their effectiveness is limited when used alone. Therefore, a refining method for low-temperature cold-pressed pecan oil is proposed. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a refining method for low-temperature cold-pressed pecan oil. By using magnetic enzyme carriers, magnetized water, and modified decolorizing agents in combination, the pecan oil is better degummed and decolorized, ensuring the quality of the finished pecan oil.
[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for refining low-temperature cold-pressed pecan oil, comprising the following steps: (1) Magnetized water and magnetic enzyme carrier were added to the pretreated pecan oil for enzymatic hydrolysis. After the enzymatic hydrolysis was completed, magnetic separation was performed to obtain degummed pecan oil. (2) Add a modified decolorizing agent to the degummed pecan oil, and after the decolorization is completed, filter the oil to obtain decolorized pecan oil; wherein the modified decolorizing agent is composed of activated clay and sugar charcoal; (3) Vacuum dehydration treatment is performed on the decolorized pecan oil to obtain refined pecan oil.
[0007] Preferably, in step (1), the pretreatment of pecan oil involves heating the pecan oil in a water bath to 70°C, adding 50wt% citric acid solution and stirring for 30 minutes, and then adjusting the pH to 5.5 with 4wt% sodium hydroxide solution; the volume ratio of pecan oil to citric acid solution is 800:1.
[0008] Preferably, the magnetized water accounts for 2-3% of the volume of the crude pecan oil; the magnetic enzyme carrier accounts for 2-2.5% of the mass of the crude pecan oil; and the enzymatic hydrolysis reaction is carried out at 50-60℃ for 2-3 hours.
[0009] Preferably, in step (1), the preparation method of the magnetic enzyme carrier is as follows: S1. Magnetic iron oxide is ultrasonically dispersed in an 80wt% ethanol solution, followed by the addition of a silane coupling agent. The mixture is reacted at 45-55℃ for 4-5 hours. After separation and drying, silanized magnetic iron oxide is obtained. S2. Silanized magnetic iron oxide, glutaraldehyde solution and sodium phosphate buffer solution at pH 6.5 were mixed, washed with deionized water, and freeze-dried for 12 hours to obtain the composite magnetic carrier. S3. Mix the composite magnetic carrier, phospholipase A1 and sodium phosphate buffer at pH 6.5. Add Tween 80 to the resulting mixture and stir at 4-5℃ for 4-4.5 hours. After magnetic separation, washing and drying, the magnetic enzyme carrier is obtained.
[0010] Preferably, in step S1, the ratio of the magnetic iron oxide to the ethanol solution is 1:100 g / mL; the silane coupling agent used is KH-550, and its volume ratio to the ethanol solution is 1:25.
[0011] Preferably, in step S2, the ratio of silanized magnetic iron oxide to glutaraldehyde solution is 1:1 g / mL; and the volume ratio of glutaraldehyde solution to sodium phosphate buffer is 1:15.
[0012] Preferably, in step S3, the mass ratio of the composite magnetic carrier to phospholipase A1 is 10:(2-3); the material-to-liquid ratio of the composite magnetic carrier to sodium phosphate buffer is 1:10 g / mL; and Tween 80 accounts for 1.5% of the total mass of the mixture.
[0013] Preferably, in step (2), the modified decolorizing agent is prepared by mixing activated clay, glucose and deionized water and then ball milling them, followed by drying to constant weight and sealing and calcining to obtain a modified decolorizing agent composed of activated clay and sugar charcoal.
[0014] Preferably, the mass ratio of the activated clay, glucose, and deionized water is 1:(0.05-0.1):2; the sealed calcination is carried out at 400-420℃ for 0.5-1h.
[0015] Preferably, in step (2), the modified decolorizing agent accounts for 1-2% of the mass of the degummed pecan oil.
[0016] This invention provides a method for refining low-temperature cold-pressed pecan oil, which has the following advantages compared with the prior art: This invention uses magnetic iron oxide as a carrier for the immobilization of phospholipase, which facilitates the separation and reuse of the magnetic enzyme carrier. To address the problem of insufficient active groups on the carrier surface, it is modified with silanization to increase the number of functional groups. With the cooperation of glutaraldehyde, the immobilization quantity and stability of phospholipase on the carrier are improved. Furthermore, an appropriate amount of magnetized water is added to improve the solubility of ordinary deionized water, increase the oil-water interface area during the reaction process, and facilitate the reaction of phospholipase and phospholipids at the oil-water interface, thereby improving the degumming effect of pecan oil.
[0017] This invention uses a modified decolorizing agent composed of activated clay and sugar charcoal, which can achieve complementary and synergistic adsorption performance. The activated clay strongly adsorbs polar pigments, while the sugar charcoal strongly adsorbs macromolecular pigments and oxidized polymers, thus improving the decolorization effect of pecan oil. In addition, the method of ball milling with water followed by sealed calcination has a stronger decolorization ability compared to directly mixing activated clay and sugar charcoal. Attached Figure Description
[0018] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 The images show the appearance of crude pecan oil and refined pecan oil in Example 7 of this invention. Detailed Implementation
[0019] The following embodiments are provided to illustrate the implementation of this application in detail, so that the process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.
[0020] Raw materials in this invention: Phospholipase A1, glutaraldehyde, sodium phosphate buffer, and citric acid were purchased from Aladdin; sodium hydroxide, magnetic iron oxide, silane coupling agent KH-550, Tween 80, activated clay, and Maclean's were purchased from Maclean's; glucose was purchased from Sichuan Xinwangbao Food Co., Ltd.; magnetized water was deionized water magnetized at room temperature for 24 hours in a magnetized water machine.
[0021] Abbreviations in this invention: Silanized magnetic iron oxide — Silanized Fe3O4 Composite magnetic carrier—KH-Fe3O4 Magnetic enzyme carrier—KH-Fe3O4-PLA1 Modified decolorizing agent – ABE-BC.
[0022] Example 1 The preparation method of KH-Fe3O4-PLA1 is as follows: S1. Magnetic iron oxide was ultrasonically dispersed in 80wt% ethanol solution at a material-to-liquid ratio of 1:100g / mL. Then, silane coupling agent KH-550 was added, and its volume ratio with ethanol solution was controlled at 1:25. The reaction was carried out at 55℃ for 4h. After separation and drying, silanized Fe3O4 was obtained. S2. Silanized Fe3O4, glutaraldehyde solution, and sodium phosphate buffer (pH 6.5) were mixed, and the ratio of silanized Fe3O4 to glutaraldehyde solution was controlled at 1:1 g / mL, and the volume ratio of glutaraldehyde solution to sodium phosphate buffer (pH 6.5) was controlled at 1:15. Then, the mixture was washed with deionized water and freeze-dried for 12 h to obtain KH-Fe3O4. S3. KH-Fe3O4, phospholipase A1 and sodium phosphate buffer (pH 6.5) were mixed, and the mass ratio of KH-Fe3O4 to phospholipase A1 was controlled at 10:3, and the material-to-liquid ratio of KH-Fe3O4 to sodium phosphate buffer (pH 6.5) was controlled at 1:10 g / mL. Tween 80 was added to the resulting mixture at 1.5% of the total mass of the mixture, and the mixture was stirred at 4℃ for 4.5 h. After magnetic separation, washing and drying, KH-Fe3O4-PLA1 was obtained.
[0023] Example 2 The preparation method of KH-Fe3O4-PLA1 is as follows: S1. Magnetic iron oxide was ultrasonically dispersed in 80wt% ethanol solution at a material-to-liquid ratio of 1:100g / mL. Then, silane coupling agent KH-550 was added, and its volume ratio with ethanol solution was controlled at 1:25. The reaction was carried out at 45℃ for 5h. After separation and drying, silanized Fe3O4 was obtained. S2. Silanized Fe3O4, glutaraldehyde solution, and sodium phosphate buffer (pH 6.5) were mixed, and the ratio of silanized Fe3O4 to glutaraldehyde solution was controlled at 1:1 g / mL, and the volume ratio of glutaraldehyde solution to sodium phosphate buffer (pH 6.5) was controlled at 1:15. Then, the mixture was washed with deionized water and freeze-dried for 12 h to obtain KH-Fe3O4. S3. KH-Fe3O4, phospholipase A1 and sodium phosphate buffer (pH 6.5) were mixed, and the mass ratio of KH-Fe3O4 to phospholipase A1 was controlled at 10:2, and the material-to-liquid ratio of KH-Fe3O4 to sodium phosphate buffer (pH 6.5) was controlled at 1:10 g / mL. Tween 80 was added to the resulting mixture at 1.5% of the total mass of the mixture, and the mixture was stirred at 5°C for 4 hours. After magnetic separation, washing and drying, KH-Fe3O4-PLA1 was obtained.
[0024] Example 3 The preparation method of ABE-BC is as follows: activated clay, glucose and deionized water are mixed in a mass ratio of 1:0.1:2 and then ball-milled. After drying to constant weight, they are sealed and calcined at 400℃ for 1 hour to obtain ABE-BC composed of activated clay and sugar char.
[0025] Example 4 The preparation method of ABE-BC is as follows: activated clay, glucose and deionized water are mixed in a mass ratio of 1:0.05:2 and then ball-milled. After drying to constant weight, the mixture is sealed and calcined at 420℃ for 0.5h to obtain ABE-BC composed of activated clay and sugar char.
[0026] Example 5 A method for refining cold-pressed pecan oil at low temperatures includes the following steps: (1) Heat the crude pecan oil in a water bath to 70°C, add 50wt% citric acid solution and stir for 30 min, control the volume ratio of crude pecan oil to citric acid solution to 800:1, and then adjust the pH to 5.5 with 4wt% sodium hydroxide solution to obtain pretreated crude pecan oil. (2) Add 3% magnetized water (by volume of crude pecan oil) and 2% KH-Fe3O4-PLA1 (by mass of crude pecan oil) to the pretreated crude pecan oil, and perform enzymatic hydrolysis at 60°C for 2 hours. After the enzymatic hydrolysis is completed, perform magnetic separation to obtain degummed pecan oil. (3) Add 2% ABE-BC to the degummed pecan oil, and after the decolorization is completed, filter the oil to obtain decolorized pecan oil. (4) Vacuum dehydration treatment is performed on the decolorized pecan oil to obtain refined pecan oil.
[0027] In this embodiment, KH-Fe3O4-PLA1 from Example 1 and ABE-BC from Example 4 are used.
[0028] Example 6 A method for refining cold-pressed pecan oil at low temperatures includes the following steps: (1) Heat the crude pecan oil in a water bath to 70°C, add 50wt% citric acid solution and stir for 30 min, control the volume ratio of crude pecan oil to citric acid solution to 800:1, and then adjust the pH to 5.5 with 4wt% sodium hydroxide solution to obtain pretreated crude pecan oil. (2) Add 2% magnetized water (by volume of crude pecan oil) and 2.5% KH-Fe3O4-PLA1 (by mass of crude pecan oil) to the pretreated crude pecan oil, and perform enzymatic hydrolysis at 50°C for 3 hours. After the enzymatic hydrolysis is completed, perform magnetic separation to obtain degummed pecan oil. (3) Add 1% ABE-BC by weight of degummed pecan oil to the degummed pecan oil, and after the decolorization is completed, filter the oil to obtain decolorized pecan oil. (4) Vacuum dehydration treatment is performed on the decolorized pecan oil to obtain refined pecan oil.
[0029] In this embodiment, KH-Fe3O4-PLA1 from Example 2 and ABE-BC from Example 3 are used.
[0030] Example 7 A method for refining cold-pressed pecan oil at low temperatures includes the following steps: (1) Heat the crude pecan oil in a water bath to 70°C, add 50wt% citric acid solution and stir for 30 min, control the volume ratio of crude pecan oil to citric acid solution to 800:1, and then adjust the pH to 5.5 with 4wt% sodium hydroxide solution to obtain pretreated crude pecan oil. (2) Add 2.5% magnetized water (by volume) and 2.2% KH-Fe3O4-PLA1 (by mass) of crude pecan oil to the pretreated crude pecan oil, and perform enzymatic hydrolysis at 55°C for 2.5 h. After the enzymatic hydrolysis is completed, perform magnetic separation to obtain degummed pecan oil. (3) Add 1.5% ABE-BC by weight of the degummed pecan oil to the degummed pecan oil, and after the decolorization is completed, filter the oil to obtain decolorized pecan oil; (4) Vacuum dehydration treatment is performed on the decolorized pecan oil to obtain refined pecan oil.
[0031] In this embodiment, KH-Fe3O4-PLA1 from Example 1 and ABE-BC from Example 3 are used.
[0032] Comparative Example 1 A method for refining cold-pressed pecan oil at low temperatures includes the following steps: (1) The pretreated pecan oil from Example 7 was used; (2) Add 2.5% deionized water (by volume of crude pecan oil) and 2.2% KH-Fe3O4-PLA1 (by mass of crude pecan oil) to the pretreated crude pecan oil, and perform enzymatic hydrolysis at 55°C for 2.5 h. After the enzymatic hydrolysis is completed, perform magnetic separation to obtain degummed pecan oil. Steps (3)-(4) are described in Example 7.
[0033] In this comparative example, KH-Fe3O4-PLA1 from Example 1 and ABE-BC from Example 3 were used.
[0034] Comparative Example 2 A method for refining low-temperature cold-pressed pecan oil is basically the same as that in Example 7, except that W-Fe3O4-PLA1 is used instead of KH-Fe3O4-PLA1.
[0035] The preparation method of W-Fe3O4-PLA1 is as follows: S1. Fe3O4, glutaraldehyde solution and sodium phosphate buffer (pH 6.5) were mixed, and the ratio of Fe3O4 to glutaraldehyde solution was controlled at 1:1 g / mL, and the volume ratio of glutaraldehyde solution to sodium phosphate buffer (pH 6.5) was controlled at 1:15. Then, the mixture was washed with deionized water and freeze-dried for 12 h to obtain W-Fe3O4. S2. Mix W-Fe3O4, phospholipase A1 and sodium phosphate buffer (pH 6.5), controlling the mass ratio of W-Fe3O4 to phospholipase A1 to be 10:3 and the material-to-liquid ratio of W-Fe3O4 to sodium phosphate buffer (pH 6.5) to be 1:10 g / mL. Add 1.5% of Tween 80 to the resulting mixture and stir at 4℃ for 4.5 h. After magnetic separation, washing and drying, W-Fe3O4-PLA1 is obtained.
[0036] Comparative Example 3 A method for refining low-temperature cold-pressed pecan oil is basically the same as that in Example 7, except that activated clay is used instead of ABE-BC.
[0037] Comparative Example 4 A method for refining low-temperature cold-pressed pecan oil is basically the same as that in Example 7, except that sugar char is used instead of ABE-BC.
[0038] The method for preparing sugar char is as follows: glucose is sealed and roasted at 400℃ for 1 hour to obtain the char.
[0039] Comparative Example 5 A method for refining low-temperature cold-pressed pecan oil is basically the same as that in Example 7, except that activated clay / sugar charcoal is used instead of ABE-BC.
[0040] The preparation method of activated clay / sugar charcoal is as follows: activated clay and sugar charcoal are mixed at a mass ratio of 1:0.1. Sugar charcoal is obtained by sealing and calcining glucose at 400℃ for 1 hour.
[0041] Performance testing 1. Degumming Rate Test: Crude pecan oil, degummed pecan oil from Examples 5-7, and Comparative Examples 1-2 were used as samples. The phosphorus content of the samples was determined according to GB / T5537-2008 "Determination of Phospholipid Content in Grain and Oil Inspection". The degumming rate was calculated using the following formula: In the formula: Phosphorus content of crude walnut oil, mg / kg; The value represents the phosphorus content of degummed pecan oil, in mg / kg.
[0042] The specific test results are shown in Table 1.
[0043] Table 1 Degumming Rate
[0044] As shown in Table 1, compared with Example 7, Comparative Example 1 did not use magnetized water, resulting in a slight decrease in the degumming rate; Comparative Example 2 did not use silane coupling agent for modification, resulting in a significant decrease in the degumming rate.
[0045] 2. Decolorization Rate Test: Using the degummed and decolorized pecan oils from Examples 5-7 and Comparative Examples 3-5 as samples, the absorbance of the samples was measured using a UV spectrometer at a wavelength of 520 nm. The specific decolorization conditions were stirring at 60°C for 25 min. The decolorization rate was calculated using the following formula: In the formula: The absorbance of degummed pecan oil; The absorbance of the decolorized pecan oil.
[0046] The specific test results are shown in Table 2.
[0047] Table 2 Decolorization rate
[0048] As shown in Table 2, compared with Example 7, the decolorization rate was reduced when activated clay was used alone as a decolorizing agent in Comparative Example 3; the decolorization rate was significantly reduced when sugar charcoal was used alone as a decolorizing agent in Comparative Example 4; and the decolorization rate was also reduced when activated clay / sugar charcoal was used as a decolorizing agent in Comparative Example 5.
[0049] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for refining low-temperature cold-pressed pecan oil, characterized in that, Includes the following steps: (1) Magnetized water and magnetic enzyme carrier were added to the pretreated pecan oil for enzymatic hydrolysis. After the enzymatic hydrolysis was completed, magnetic separation was performed to obtain degummed pecan oil. (2) Add a modified decolorizing agent to the degummed pecan oil, and after the decolorization is completed, filter it to obtain decolorized pecan oil; The modified decolorizing agent is composed of activated clay and sugar charcoal; (3) Vacuum dehydration treatment is performed on the decolorized pecan oil to obtain refined pecan oil.
2. The refining method for low-temperature cold-pressed pecan oil according to claim 1, characterized in that, In step (1), the pretreatment of pecan oil involves heating the pecan oil in a water bath to 70°C, adding 50wt% citric acid solution and stirring for 30 minutes, and then adjusting the pH to 5.5 with 4wt% sodium hydroxide solution; the volume ratio of pecan oil to citric acid solution is 800:
1.
3. The refining method for low-temperature cold-pressed pecan oil according to claim 2, characterized in that, The magnetized water accounts for 2-3% of the volume of the crude pecan oil; the magnetic enzyme carrier accounts for 2-2.5% of the mass of the crude pecan oil; and the enzymatic hydrolysis reaction is carried out at 50-60℃ for 2-3 hours.
4. The refining method for low-temperature cold-pressed pecan oil according to claim 1, characterized in that, In step (1), the preparation method of the magnetic enzyme carrier is as follows: S1. Magnetic iron oxide is ultrasonically dispersed in an 80wt% ethanol solution, followed by the addition of a silane coupling agent. The mixture is reacted at 45-55℃ for 4-5 hours. After separation and drying, silanized magnetic iron oxide is obtained. S2. Silanized magnetic iron oxide, glutaraldehyde solution and sodium phosphate buffer solution at pH 6.5 were mixed, washed with deionized water, and freeze-dried for 12 hours to obtain the composite magnetic carrier. S3. Mix the composite magnetic carrier, phospholipase A1 and sodium phosphate buffer at pH 6.
5. Add Tween 80 to the resulting mixture and stir at 4-5℃ for 4-4.5 hours. After magnetic separation, washing and drying, the magnetic enzyme carrier is obtained.
5. The refining method for low-temperature cold-pressed pecan oil according to claim 4, characterized in that, In step S1, the ratio of magnetic iron oxide to ethanol solution is 1:100 g / mL; the silane coupling agent used is KH-550, and its volume ratio to ethanol solution is 1:
25.
6. The refining method for low-temperature cold-pressed pecan oil according to claim 4, characterized in that, In step S2, the ratio of silanized magnetic iron oxide to glutaraldehyde solution is 1:1 g / mL; the volume ratio of glutaraldehyde solution to sodium phosphate buffer is 1:
15.
7. The refining method for low-temperature cold-pressed pecan oil according to claim 4, characterized in that, In step S3, the mass ratio of the composite magnetic carrier to phospholipase A1 is 10:(2-3); the material-to-liquid ratio of the composite magnetic carrier to sodium phosphate buffer is 1:10 g / mL; and Tween 80 accounts for 1.5% of the total mass of the mixture.
8. The refining method for low-temperature cold-pressed pecan oil according to claim 1, characterized in that, In step (2), the modified decolorizing agent is prepared by mixing activated clay, glucose and deionized water and then ball milling them, drying them to constant weight and then sealing and calcining them to obtain a modified decolorizing agent composed of activated clay and sugar charcoal.
9. The refining method for low-temperature cold-pressed pecan oil according to claim 8, characterized in that, The mass ratio of activated clay, glucose, and deionized water is 1:(0.05-0.1):2; the sealed calcination is carried out at 400-420℃ for 0.5-1h.
10. The refining method for low-temperature cold-pressed pecan oil according to claim 1, characterized in that, In step (2), the modified decolorizing agent accounts for 1-2% of the mass of the degummed pecan oil.