Frying oil purification method

Abstract

The invention relates to the technical field of frying oil treatment, in particular to a frying oil purification method which comprises the following steps: preparing an antioxidant part; wherein the anti-oxidation piece is composed of stainless steel, a microporous silicon dioxide layer, vitamin E and a slow-release film; putting the antioxidant part into the frying oil in advance to start frying operation, after the frying operation is finished, taking out the antioxidant part, carrying out separation treatment, and removing food residues to obtain roughly filtered oil; and adding the modified adsorbent into the coarsely filtered oil, heating and stirring for adsorption and purification, taking out after adsorption and purification are finished, and filtering. Wherein the modified adsorbent is prepared from activated clay and magnesium silicate. The modified adsorbent is prepared from the activated clay, the sodium silicate and the magnesium sulfate, so that the activated clay and the magnesium silicate are compounded; wherein the activated clay is high in deacidification and decolorization capacity, the magnesium silicate is selective in depolarity and low in oil loss, and the activated clay and the magnesium silicate are compounded to complement each other in advantages, so that efficient purification of the frying oil is realized.

Description

Technical Field

[0001] This invention relates to the field of frying oil treatment technology, specifically a method for purifying frying oil. Background Technology

[0002] During the frying process, food undergoes hydrolysis, oxidation, and polymerization reactions due to the interaction of factors such as high temperature, moisture in the food, and oxygen. This produces polar substances such as free fatty acids, oxidized triglycerides, and oxidized triglyceride polymers. At the same time, the acid value of the frying oil gradually increases.

[0003] When the acid value and / or polar component content of frying oil exceeds hygiene standards, it needs to be discarded, resulting in significant waste. Currently, frying oil can be purified using adsorbents to reduce its acid value and polar components, bringing it back to hygiene standards for reuse; however, its lifespan is relatively short. Therefore, a method for purifying frying oil is proposed. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for purifying frying oil, which extends the service life of frying oil within safety and hygiene standards, while achieving efficient purification of frying oil.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for purifying frying oil, comprising the following steps: (1) Prepare an antioxidant component; wherein the antioxidant component is composed of stainless steel, a microporous silica layer, vitamin E and a slow-release film; (2) Place the antioxidant parts into the frying oil in advance to start the frying operation. After the frying operation is completed, take out the antioxidant parts and separate them to remove food residue and obtain coarse filtered oil. (3) Add the modified adsorbent to the coarse filter oil, heat and stir to carry out adsorption purification. After the adsorption purification is completed, take it out and filter it. The modified adsorbent is composed of activated clay and magnesium silicate.

[0006] Preferably, in step (1), the preparation method of the antioxidant component is as follows: S11, the surfactant is stirred and dissolved in a 40wt% ethanol solution, and then ammonia and tetraethyl orthosilicate are added in sequence, and reacted at 40-50℃ for 1.5-2.5h to obtain silica sol; S12, the stainless steel is immersed in the silica sol for 10-20min, and then slowly pulled up to make the silica sol uniformly adhere to the stainless steel surface to obtain pretreated stainless steel; S13, the pretreated stainless steel is first reacted at 60-70℃ for 2-3h, and then calcined at 450-500℃ for 3-4h to form a microporous silica layer on the stainless steel surface to obtain silicon-containing stainless steel; S14, the silicon-containing stainless steel is immersed in an antioxidant solution and ultrasonically treated for 1-1.5h, then dried and the obtained silicon-containing antioxidant stainless steel is immersed in an ethyl cellulose solution for 10-20min, then dried to form a slow-release film on the microporous silica layer to obtain the antioxidant component.

[0007] Preferably, in step S11, the surfactant is P123, and its ratio to the ethanol solution is 1:50 g / mL; the mass ratio of surfactant, ammonia and tetraethyl orthosilicate is 1:4:4.5.

[0008] Preferably, in step S14, the antioxidant solution is composed of vitamin E and anhydrous ethanol mixed in a mass ratio of 1:2.

[0009] Preferably, in step S14, the ethyl cellulose solution is prepared by mixing ethyl cellulose and anhydrous ethanol at a material-to-liquid ratio of 1:15 g / mL.

[0010] Preferably, in step (2), the antioxidant accounts for more than 3% of the frying oil mass; in step (3), the heating and stirring is carried out at 60-80℃ for 40-50 minutes; and the modified adsorbent accounts for 2-3% of the coarse filter oil mass.

[0011] Preferably, in step (3), the modified adsorbent is prepared as follows: S21, activated clay is ultrasonically dispersed in deionized water to obtain a suspension; S22, sodium silicate solution and magnesium sulfate solution are added to the suspension by stirring, the pH is adjusted to 7.5, and stirring is continued for 1.5-2 hours to obtain a mixture; S23, the mixture is filtered, washed and dried to obtain the modified adsorbent.

[0012] Preferably, in step S21, the ratio of activated clay to deionized water is 1:5 g / mL.

[0013] Preferably, in step S22, the sodium silicate solution is prepared by mixing sodium silicate and deionized water at a ratio of 1.5:10 g / mL; the magnesium sulfate solution is prepared by mixing magnesium sulfate and deionized water at a ratio of 1:5 g / mL.

[0014] Preferably, the mass ratio of the activated clay, sodium silicate, and magnesium sulfate is 1:0.3:0.5.

[0015] This invention provides a method for purifying frying oil, which has the following advantages compared with the prior art: This invention uses stainless steel as the main carrier, with a microporous silica layer covering its surface as a secondary carrier. Vitamin E is then filled into the secondary carrier, and an ethyl cellulose slow-release film is formed on its surface. During high-temperature frying, the slow-release film softens or ruptures, and the vitamin E in the microporous silica layer is slowly released into the frying oil, exerting an antioxidant effect and slowing down the decomposition time of vitamin E, thereby extending the service life of the frying oil within safety and hygiene standards. Moreover, the presence of the slow-release film can also effectively prevent the oxidation of vitamin E, allowing the antioxidant component to be stored in the air for a long time. In addition, the antioxidant component, as a whole, can be easily separated from the frying oil.

[0016] This invention utilizes activated clay, sodium silicate, and magnesium sulfate to prepare a modified adsorbent, thereby combining activated clay and magnesium silicate. Activated clay has strong deacidification and decolorization capabilities, while magnesium silicate selectively depolarizes and has low oil loss. The combination of the two can complement each other's advantages, achieving efficient purification of frying oil. Attached Figure Description

[0017] 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 Images of the original coarse filtered oil of the present invention, and the purified coarse filtered oil products of Comparative Example 3 and Example 7; Figure 2 This is a schematic diagram of the silicon-containing stainless steel structure of the present invention. Detailed Implementation

[0018] 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.

[0019] The raw materials used in this invention are: ammonia water (analytical grade, Tianjin Kemeio Chemical Reagent Co., Ltd.); anhydrous ethanol (analytical grade, Tianjin Kemeio Chemical Reagent Co., Ltd.); tetraethyl orthosilicate (97%), Shanghai Dibai Biotechnology Co., Ltd.; surfactant P123, Shanghai Jieshikai Biotechnology Co., Ltd.; vitamin E, COFCO Tianke Bioengineering (Tianjin) Co., Ltd.; ethyl cellulose (EC9), analytical grade, Sinopharm Holding Chemical Reagent Co., Ltd.; activated clay, Huangshan Baiyue Activated Clay Co., Ltd.; sodium silicate (industrial grade), Qingdao Dongyue Sodium Silicate Co., Ltd.; and magnesium sulfate (analytical grade), Jiangsu Qiangsheng Functional Chemical Co., Ltd.

[0020] In this invention, fresh palm oil is used as the initial frying oil to fry the dough for instant noodles. The initial acid value of the frying oil is ≤0.2mg / g, and the polar component is ≤6.3%. The hygiene standard for frying oil used in instant noodles is: acid value ≤1.8mg / g, polar component ≤27.0%. The specific frying process is as follows: Pour fresh palm oil into the pot, heat it to 145℃, and fry the dough continuously. During this period, the acid value of the frying oil is checked every 1 hour. Frying is stopped when the acid value is ≤1.5mg / g. After filtering to remove food residue, coarse filtered oil is obtained. Acid value determination standards: GB / T 5530-2017 and GB 17400-2015; Standard for determination of polar component content: GB 2716-2018.

[0021] Example 1 The preparation method of the antioxidant component is as follows: S11. Dissolve surfactant P123 in 40wt% ethanol solution by stirring at a material-to-liquid ratio of 1:50 g / mL. Then, add ammonia and tetraethyl orthosilicate by stirring in sequence. React at 50℃ for 1.5 h to obtain silica sol. The mass ratio of surfactant, ammonia and tetraethyl orthosilicate is 1:4:4.5. S12. Immerse the stainless steel in silica sol for 20 minutes, then slowly lift it to allow the silica sol to adhere evenly to the surface of the stainless steel, thus obtaining pretreated stainless steel. S13. First, the pretreated stainless steel is reacted at 60°C for 3 hours, and then calcined at 450°C for 4 hours to form a microporous silica layer on the surface of the stainless steel, thus obtaining a silicon-containing stainless steel. S14. Immerse the silicon-containing stainless steel in an antioxidant solution (a mixture of vitamin E and anhydrous ethanol at a mass ratio of 1:2) and sonicate for 1 hour. Remove and dry to remove ethanol. Then immerse the resulting silicon-containing antioxidant stainless steel in an ethyl cellulose solution (a mixture of ethyl cellulose and anhydrous ethanol at a material-to-liquid ratio of 1:15 g / mL) for 20 minutes. Remove and dry to remove ethanol. A slow-release film is formed in the microporous silica layer to obtain the antioxidant part.

[0022] Example 2 The preparation method of the antioxidant component is as follows: S11. Dissolve surfactant P123 in a 40wt% ethanol solution by stirring at a material-to-liquid ratio of 1:50 g / mL. Then, add ammonia and tetraethyl orthosilicate sequentially by stirring. React at 40℃ for 2.5 h to obtain silica sol. The mass ratio of surfactant, ammonia and tetraethyl orthosilicate is 1:4:4.5. S12. Immerse the stainless steel in silica sol for 10 minutes, then slowly lift it to allow the silica sol to adhere evenly to the surface of the stainless steel, thus obtaining pretreated stainless steel. S13. First, the pretreated stainless steel is reacted at 70°C for 2 hours, and then calcined at 500°C for 3 hours to form a microporous silica layer on the surface of the stainless steel, thus obtaining a silicon-containing stainless steel. S14. Immerse the silicon-containing stainless steel in an antioxidant solution (a mixture of vitamin E and anhydrous ethanol at a mass ratio of 1:2) and sonicate for 1.5 h. Remove and dry to remove ethanol. Then immerse the resulting silicon-containing antioxidant stainless steel in an ethyl cellulose solution (a mixture of ethyl cellulose and anhydrous ethanol at a material-liquid ratio of 1:15 g / mL) for 10 min. Remove and dry to remove ethanol. A slow-release film is formed in the microporous silica layer to obtain the antioxidant part.

[0023] Example 3 The preparation method of the modified adsorbent is as follows: S21. Disperse activated clay in deionized water using ultrasonication at a material-to-liquid ratio of 1:5 g / mL to obtain a suspension; S22. Add sodium silicate solution and magnesium sulfate solution to the suspension with stirring, adjust the pH to 7.5, and continue stirring for 2 hours to obtain a mixture; wherein the sodium silicate solution is prepared by mixing sodium silicate and deionized water at a material-to-liquid ratio of 1.5:10 g / mL; the magnesium sulfate solution is prepared by mixing magnesium sulfate and deionized water at a material-to-liquid ratio of 1:5 g / mL; the mass ratio of activated clay, sodium silicate, and magnesium sulfate is 1:0.3:0.5; S23. The mixture is filtered, washed and dried to obtain a modified adsorbent.

[0024] Example 4 The preparation method of the modified adsorbent is as follows: S21. Disperse activated clay in deionized water using ultrasonication at a material-to-liquid ratio of 1:5 g / mL to obtain a suspension; S22. Add sodium silicate solution and magnesium sulfate solution to the suspension with stirring, adjust the pH to 7.5, and continue stirring for 1.5 hours to obtain a mixture; wherein the sodium silicate solution is prepared by mixing sodium silicate and deionized water at a material-to-liquid ratio of 1.5:10 g / mL; the magnesium sulfate solution is prepared by mixing magnesium sulfate and deionized water at a material-to-liquid ratio of 1:5 g / mL; the mass ratio of activated clay, sodium silicate, and magnesium sulfate is 1:0.3:0.5; S23. The mixture is filtered, washed and dried to obtain a modified adsorbent.

[0025] Example 5 A method for purifying frying oil includes the following steps: (1) Prepare antioxidant components; (2) Add antioxidants accounting for 3% of the frying oil mass into the frying oil in advance to start the frying operation. After the frying operation is completed, remove the antioxidants and separate them to remove food residue and obtain coarse filtered oil. (3) Add 3% of the modified adsorbent by mass of the coarse filter oil to the coarse filter oil, stir at 60°C for 50 min for adsorption and purification, take it out after adsorption and purification, and then filter it.

[0026] In this embodiment, the antioxidant component from Example 1 and the modified adsorbent from Example 4 are used.

[0027] Example 6 A method for purifying frying oil includes the following steps: (1) Prepare antioxidant components; (2) Add antioxidants accounting for 4% of the frying oil mass into the frying oil in advance to start the frying operation. After the frying operation is completed, remove the antioxidants and separate them to remove food residue and obtain coarse filtered oil. (3) Add 2% of the modified adsorbent by mass of the coarse filter oil to the coarse filter oil, stir at 80°C for 40 min for adsorption and purification, take it out after adsorption and purification, and then filter it.

[0028] In this embodiment, the antioxidant component from Example 2 and the modified adsorbent from Example 3 are used.

[0029] Example 7 A method for purifying frying oil includes the following steps: (1) Prepare antioxidant components; (2) Add antioxidants accounting for 4% of the frying oil mass into the frying oil in advance to start the frying operation. After the frying operation is completed, remove the antioxidants and separate them to remove food residue and obtain coarse filtered oil. (3) Add 3% of the modified adsorbent by mass of the coarse filter oil to the coarse filter oil, stir at 70°C for 45 min for adsorption and purification, take it out after adsorption and purification, and then filter it.

[0030] In this embodiment, the antioxidant component from Example 1 and the modified adsorbent from Example 3 are used.

[0031] Comparative Example 1 A method for purifying frying oil includes the following steps: (1) Add 0.05% of vitamin E by weight of frying oil to the frying oil in advance to start the frying operation. After the frying operation is completed, perform separation treatment to remove food residue and obtain coarse filtered oil. (2) Add 3% of the modified adsorbent (prepared in Example 3) of the coarse filter oil to the coarse filter oil, stir at 70°C for 45 min for adsorption and purification, take it out after adsorption and purification, and then filter it.

[0032] Comparative Example 2 A method for purifying frying oil is basically the same as that in Example 7, except that the silicon-containing anti-oxidation stainless steel in Example 3 is used as the anti-oxidation component.

[0033] Comparative Example 3 A method for purifying frying oil includes the following steps: (1) Preparation of antioxidant components (prepared in Example 1); (2) Add antioxidants accounting for 4% of the frying oil mass into the frying oil in advance to start the frying operation. After the frying operation is completed, remove the antioxidants and separate them to remove food residue and obtain coarse filtered oil. (3) Add 3% of the activated clay by mass of the coarse filter oil to the coarse filter oil, stir at 70°C for 45 minutes for adsorption purification, take it out after adsorption purification is completed, and then filter it.

[0034] Comparative Example 4 A method for purifying frying oil includes the following steps: (1) Preparation of antioxidant components (prepared in Example 1); (2) Add antioxidants accounting for 4% of the frying oil mass into the frying oil in advance to start the frying operation. After the frying operation is completed, remove the antioxidants and separate them to remove food residue and obtain coarse filtered oil. (3) Add 3% magnesium silicate of the coarse filter oil to the coarse filter oil and stir at 70°C for 45 minutes for adsorption purification. After the adsorption purification is completed, take it out and filter it.

[0035] Performance testing The purification methods described in Examples 5-7 and Comparative Examples 1-4 were used.

[0036] 1. The time required for continuous frying of fresh palm oil with an acid value ≤0.2mg / g to rise to an acid value ≤1.5mg / g. Specific results are shown in Table 1.

[0037] Table 1 Time Used As shown in Table 1, the fresh palm oil in Examples 5, 6, and 7 only reached an acid value of 1.5 mg / g after continuous frying for more than 35 hours. Compared with Example 7, Comparative Example 1, which directly used vitamin E, saw a faster increase in acid value and a 14-hour reduction in frying oil usage time. Comparative Example 2, which did not form a slow-release film on the microporous silica layer, experienced a relatively slower increase in acid value and a 9-hour reduction in frying oil usage time. Palm oil without added antioxidants only required 20 hours to reach an acid value of 1.5 mg / g.

[0038] 2. Detection of acid value and polar component content of coarse filtered oil. Specific results are shown in Table 2.

[0039] Table 2 Acid value and polar component content As shown in Table 2, compared with Example 7, the purification effect of Comparative Example 3 using activated clay alone and Comparative Example 4 using magnesium silicate alone was worse.

[0040] 3. Determination of the color, transparency, and odor of the coarse filtered oil after adsorption purification. The specific results are shown in Table 3.

[0041] Table 3 Color, Transparency, and Odor Combination Figure 1 And Table 3, as shown Figure 1 As shown in (a), the coarse filtered oil in its original state is dark in color and has an odor; Figure 1 As shown in (b), the purified crude filter oil in Comparative Example 3 was darker in color and had no odor; Figure 1 As shown in (c), the purified crude filter oil in Example 7 is light in color and odorless.

[0042] Combination Figure 2 , Figure 2 The silicon-containing stainless steel in (a) adopts a ring structure; Figure 2 (b) The stainless steel is in a plate-like structure.

[0043] 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 purifying frying oil, characterized in that, Includes the following steps: (1) Prepare an antioxidant component; wherein the antioxidant component is composed of stainless steel, a microporous silica layer, vitamin E and a slow-release film; (2) Place the antioxidant parts into the frying oil in advance to start the frying operation. After the frying operation is completed, take out the antioxidant parts and separate them to remove food residue and obtain coarse filtered oil. (3) Add the modified adsorbent to the coarse filter oil, heat and stir to carry out adsorption purification. After the adsorption purification is completed, take it out and filter it. The modified adsorbent is composed of activated clay and magnesium silicate.

2. The method for purifying frying oil according to claim 1, characterized in that, In step (1), the preparation method of the antioxidant component is as follows: S11. Dissolve the surfactant in a 40wt% ethanol solution by stirring, then add ammonia and tetraethyl orthosilicate by stirring in sequence, and react at 40-50℃ for 1.5-2.5h to obtain silica sol; S12. Immerse the stainless steel in silica sol for 10-20 minutes, then slowly lift it to allow the silica sol to adhere evenly to the surface of the stainless steel, thus obtaining pretreated stainless steel. S13. First, react the pretreated stainless steel at 60-70℃ for 2-3 hours, and then calcine it at 450-500℃ for 3-4 hours to form a microporous silica layer on the surface of the stainless steel, thus obtaining a silicon-containing stainless steel. S14. Immerse the silicon-containing stainless steel in an antioxidant solution and sonicate for 1-1.5 hours. Remove and dry. Immerse the resulting silicon-containing antioxidant stainless steel in an ethyl cellulose solution for 10-20 minutes. Remove and dry. A slow-release film is formed in the microporous silica layer to obtain the antioxidant part.

3. The method for purifying frying oil according to claim 2, characterized in that, In step S11, the surfactant used is P123, and its ratio to the ethanol solution is 1:50 g / mL; the mass ratio of surfactant, ammonia and tetraethyl orthosilicate is 1:4:4.

5.

4. The method for purifying frying oil according to claim 2, characterized in that, In step S14, the antioxidant solution is composed of vitamin E and anhydrous ethanol mixed in a mass ratio of 1:

2.

5. The method for purifying frying oil according to claim 2, characterized in that, In step S14, the ethyl cellulose solution is prepared by mixing ethyl cellulose and anhydrous ethanol at a material-to-liquid ratio of 1:15 g / mL.

6. The method for purifying frying oil according to claim 1, characterized in that, In step (2), the antioxidant component accounts for more than 3% of the frying oil mass; in step (3), the heating and stirring is carried out at 60-80℃ for 40-50 minutes; the modified adsorbent accounts for 2-3% of the coarse filter oil mass.

7. The method for purifying frying oil according to claim 1, characterized in that, In step (3), the modified adsorbent is prepared as follows: S21. Activated clay is ultrasonically dispersed in deionized water to obtain a suspension; S22. Add sodium silicate solution and magnesium sulfate solution to the suspension while stirring, adjust the pH to 7.5, and continue stirring for 1.5-2 hours to obtain a mixture; S23. The mixture is filtered, washed and dried to obtain a modified adsorbent.

8. The method for purifying frying oil according to claim 7, characterized in that, In step S21, the ratio of activated clay to deionized water is 1:5 g / mL.

9. The method for purifying frying oil according to claim 7, characterized in that, In step S22, the sodium silicate solution is prepared by mixing sodium silicate and deionized water at a ratio of 1.5:10 g / mL; the magnesium sulfate solution is prepared by mixing magnesium sulfate and deionized water at a ratio of 1:5 g / mL.

10. The method for purifying frying oil according to claim 9, characterized in that, The mass ratio of the activated clay, sodium silicate, and magnesium sulfate is 1:0.3:0.5.

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