Method for decolorizing and deodorizing edible oil

Abstract

The invention relates to an edible oil decolorizing and deodorizing method which comprises the following steps: S1, adding an adsorbent into an edible oil crude product under a vacuum condition, heating, stirring and filtering to obtain an intermediate product; s2, transferring the intermediate product into a deodorization tower, and carrying out deodorization treatment to obtain decolorized and deodorized edible oil; the modified activated carbon-bentonite composite material with an adsorption function is obtained by reacting acrylic resin containing epoxy groups with carboxylated bentonite and carboxylated activated carbon, so that the specific surface area and porosity of the modified activated carbon-bentonite composite material are improved; a large number of carbonyl groups, carboxyl groups and other groups are introduced to the surface of the modified activated carbon-bentonite composite material, a synergistic effect can be formed, pigments and peculiar smell molecules in the edible oil are more effectively adsorbed, the adsorption performance is improved, the adsorption efficiency is enhanced, the raw materials are safe and environmentally friendly, separation is easy after adsorption, residues are few, and the method is suitable for industrial production. The color and the stability of the grease can be effectively improved.

Description

Technical Field

[0001] The invention belongs to the field of oil refining, and particularly relates to a method for decolorizing and deodorizing edible oil. Background Art

[0002] During the edible oil refining process, decolorization and deodorization are key steps in determining the quality of the oil. Traditional decolorization processes typically use adsorbents such as activated carbon and natural bentonite to remove pigments and impurities from the oil through physical adsorption. However, although activated carbon has a high specific surface area and adsorption capacity, its non-selective adsorption characteristics can easily lead to the loss of beneficial components such as unsaturated fatty acids in the oil (usually up to 3-5%). In addition, due to the single surface functional group of natural bentonite, its chemical adsorption capacity for polar pigment molecules (such as chlorophyll derivatives, monascus, etc.) is insufficient, resulting in low decolorization efficiency, especially for heat-stable pigments, where the removal rate is often less than 85%.

[0003] In the deodorization process, high-temperature steam distillation (230-250°C) is widely used to remove volatile odorous substances. However, high temperatures can easily trigger the formation of trans fatty acids and lead to significant losses of heat-sensitive nutrients such as vitamin E (loss rates can reach over 40%). Furthermore, the traditional process requires separate decolorization and deodorization steps. After decolorization, the temperature must be raised again to the high temperature required for deodorization, resulting in energy waste (energy consumption increases by approximately 30%) and the accumulation of oil thermal oxidation byproducts.

[0004] The core problems of existing technologies include: (1) insufficient chemical adsorption capacity of adsorbents for pigments, resulting in reliance on physical adsorption, which limits decolorization efficiency; (2) non-selective interactions between adsorbents and oil components, which increase nutritional losses; (3) mismatched decolorization and deodorization process conditions, with repeated heating exacerbating oil oxidation and nutritional damage; and (4) poor adsorbent synergy, with traditional mechanical mixing methods resulting in low interfacial compatibility and difficulty in efficiently utilizing adsorption sites. These problems have limited the development of edible oils with high nutritional value, and there is an urgent need to achieve efficient and low-cost integrated decolorization and deodorization technology through material modification and process optimization.

[0005] Therefore, it is urgent to find a technical solution that can solve the defects of the current existing technology. Summary of the Invention

[0006] The present invention discloses a method for decolorizing and deodorizing edible oil, comprising the following steps:

[0007] S1. Under vacuum conditions, an adsorbent is added to the crude edible oil product, heated and stirred, and filtered to obtain an intermediate product;

[0008] S2. The intermediate product is transferred to a deodorization tower for deodorization to obtain decolorized and deodorized edible oil;

[0009] Wherein, the adsorbent is a modified activated carbon-bentonite composite material;

[0010] The modified activated carbon-bentonite composite material is obtained by reacting activated carbon, bentonite and acrylic resin containing epoxy groups.

[0011] Furthermore, in step S1, the heating temperature is 100-110°C.

[0012] Furthermore, in step S2, the deodorization temperature is 100-120°C.

[0013] Furthermore, the adsorbent is added in an amount of 10-15% by weight of the edible oil.

[0014] Furthermore, the preparation method of the adsorbent comprises the following steps:

[0015] L1. The epoxidized soybean oil, acrylic acid and polymerization inhibitor are mixed and heated in the presence of a catalyst to obtain an intermediate product;

[0016] L2 The intermediate product, tetraethylene glycol diacrylate, n-propanol, 1,4-butanediol, an initiator and an emulsifier were mixed, and after emulsification, polyglycidyl methacrylate was added and mixed uniformly. After the reaction at room temperature, the reaction was heated to obtain an acrylic resin containing an epoxy group;

[0017] L3. Under the protection of inert gas, an epoxy-containing acrylic resin, carboxylated activated carbon, carboxylated bentonite, and a catalyst are mixed and heated to react to obtain a modified activated carbon-bentonite composite material.

[0018] Furthermore, in step L1, the temperature of the heating reaction is 100-120°C.

[0019] Furthermore, in step L2, the emulsifier is a mixture of sodium lauryl sulfate, polyvinyl alcohol and water.

[0020] Furthermore, in step L3, the temperature of the heating reaction is 100-120°C.

[0021] Furthermore, in step L3, the mass ratio of the carboxylated activated carbon to the carboxylated bentonite is 1-5:1-3.

[0022] The present invention has the following beneficial effects:

[0023] The present invention adopts a modified activated carbon-bentonite composite material as an adsorbent for edible oil. First, epoxidized soybean oil and acrylic acid are reacted under the action of a catalyst and an inhibitor to obtain an intermediate product having an epoxy group. Then, the intermediate product is used as a monomer, tetraethylene glycol diacrylate is used as a cross-linking agent, and poly(glycidyl methacrylate) is used as a seed emulsion for polymerization to obtain an acrylic resin containing epoxy groups with an adsorption function. Then, the acrylic resin containing epoxy groups is reacted with carboxylated bentonite and carboxylated activated carbon, and cross-linked to obtain a modified activated carbon-bentonite composite material with an adsorption function. Not only is the specific surface area and porosity of the modified activated carbon-bentonite composite material increased, but a large number of carbonyl groups, carboxyl groups and the like are introduced into the surface of the modified activated carbon-bentonite composite material, which can form a synergistic effect and more effectively adsorb pigments and odor molecules in the edible oil, thereby improving adsorption performance and enhancing adsorption efficiency. In addition, the raw materials are safe and environmentally friendly, easy to separate after adsorption, and less residue is left, thereby effectively improving the color and stability of the oil. DETAILED DESCRIPTION

[0024] In order to more clearly illustrate the technical solution of the present invention, the following examples are given. Unless otherwise stated, the raw materials, reactions and post-treatment methods shown in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0025] In the embodiment, the crude edible oil product is a crude peanut oil product.

[0026] Hydroquinone, polymerization inhibitor.

[0027] Triphenylphosphine, catalyst.

[0028] Azobisisobutyronitrile, initiator.

[0029] Epoxidized soybean oil, CAS: 8013-07-8, was purchased from Shandong Ranxi Chemical Technology Co., Ltd.

[0030] Poly(glycidyl methacrylate), P757736, was purchased from Maclean.

[0031] Polyvinyl alcohol (PVA), with an average degree of polymerization of 1750, was purchased from Tianjin Tianda Chemical Reagent Factory.

[0032] Activated clay was purchased from Jinan Tonghui Chemical Co., Ltd.

[0033] Example 1

[0034] A method for decolorizing and deodorizing edible oil comprises the following steps:

[0035] S1. Under vacuum conditions, the crude edible oil product was heated to 85 ° C, and then 10% of the weight of the edible oil adsorbent was added to the crude edible oil product, heated to 105 ° C and stirred for 30 minutes, and filtered to obtain an intermediate product;

[0036] S2. The intermediate product was transferred to a deodorization tower, heated to 100°C, and directly introduced into the intermediate product at a pressure of 0.3MPa under vacuum conditions, accounting for 15% by weight of steam for deodorization for 3h to obtain decolorized and deodorized edible oil;

[0037] Wherein, the adsorbent is a modified activated carbon-bentonite composite material;

[0038] The preparation method of the adsorbent comprises the following steps:

[0039] L1. Epoxidized soybean oil, acrylic acid, and a polymerization inhibitor were mixed, heated to 110°C in the presence of a catalyst, and reacted for 2 h to obtain an intermediate product;

[0040] The mass ratio of the epoxidized soybean oil, acrylic acid, polymerization inhibitor and catalyst is 8:1:0.1:0.1;

[0041] L2. 10 g of the intermediate product, 10 ml of tetraethylene glycol diacrylate, 10 ml of n-propanol, 10 ml of 1,4-butanediol, 0.5 g of an initiator, and 200 ml of an emulsifier were mixed. After emulsification, 12 ml of polyglycidyl methacrylate was added and mixed evenly. The mixture was reacted at room temperature for 16 h, then heated to 70 ° C and continued to react for 16 h. The mixture was filtered and washed to obtain an acrylic resin containing an epoxy group.

[0042] Wherein, the emulsifier is a mixture of sodium lauryl sulfate, polyvinyl alcohol and water, the content of the sodium lauryl sulfate is 0.2wt%, and the content of the polyvinyl alcohol is 0.5wt%;

[0043] L3-1. The activated carbon was immersed in 7 mol / L nitric acid solution, heated to 80 ° C for 8h, washed, and dried to obtain carboxylated activated carbon;

[0044] L3-2. The bentonite was soaked in a 1.5 mol / L dopamine hydrochloride solution at a pH of 8.5, heated to 80 ° C for 8h, washed and dried to obtain polydopamine - bentonite;

[0045] L3-3. Using glycerol as a solvent, polydopamine - bentonite and potassium bicarbonate were mixed evenly (mass ratio of 1:5), heated to 180 ° C for 30 min, washed, and dried to obtain carboxylated bentonite;

[0046] L3-4. Under nitrogen, an epoxy-containing acrylic resin, carboxylated activated carbon, carboxylated bentonite, and a catalyst were mixed and heated to 110 ° C for 9 h to obtain a modified activated carbon - bentonite composite material;

[0047] The mass ratio of the epoxy-containing acrylic resin, carboxylated activated carbon, carboxylated bentonite, and catalyst is 1:1:1:0.1.

[0048] Example 2

[0049] A method for decolorizing and deodorizing edible oil comprises the following steps:

[0050] S1. Under vacuum conditions, the crude edible oil product was heated to 85 ° C, and then 10% of the weight of the edible oil adsorbent was added to the crude edible oil product, heated to 105 ° C and stirred for 30 minutes, and filtered to obtain an intermediate product;

[0051] S2. The intermediate product was transferred to a deodorization tower, heated to 100°C, and directly introduced into the intermediate product at a pressure of 0.3MPa under vacuum conditions, accounting for 15% by weight of steam for deodorization for 3h to obtain decolorized and deodorized edible oil;

[0052] Wherein, the adsorbent is a modified activated carbon-bentonite composite material;

[0053] The preparation method of the adsorbent comprises the following steps:

[0054] L1. Epoxidized soybean oil, acrylic acid, and a polymerization inhibitor were mixed, heated to 110°C in the presence of a catalyst, and reacted for 2 h to obtain an intermediate product;

[0055] The mass ratio of the epoxidized soybean oil, acrylic acid, polymerization inhibitor and catalyst is 8:1:0.1:0.1;

[0056] L2. 10 g of the intermediate product, 10 ml of tetraethylene glycol diacrylate, 10 ml of n-propanol, 10 ml of 1,4-butanediol, 0.5 g of an initiator, and 200 ml of an emulsifier were mixed. After emulsification, 12 ml of polyglycidyl methacrylate was added and mixed evenly. The mixture was reacted at room temperature for 16 h, then heated to 70 ° C and continued to react for 16 h. The mixture was filtered and washed to obtain an acrylic resin containing an epoxy group.

[0057] Wherein, the emulsifier is a mixture of sodium lauryl sulfate, polyvinyl alcohol and water, the content of the sodium lauryl sulfate is 0.2wt%, and the content of the polyvinyl alcohol is 0.5wt%;

[0058] L3-1. The activated carbon was immersed in 7 mol / L nitric acid solution, heated to 80 ° C for 8h, washed, and dried to obtain carboxylated activated carbon;

[0059] L3-2. The bentonite was soaked in a 1.5 mol / L dopamine hydrochloride solution at a pH of 8.5, heated to 80 ° C for 8h, washed and dried to obtain polydopamine - bentonite;

[0060] L3-3. Using glycerol as a solvent, polydopamine - bentonite and potassium bicarbonate were mixed evenly (mass ratio of 1:5), heated to 180 ° C for 30 min, washed, and dried to obtain carboxylated bentonite;

[0061] L3-4. Under nitrogen, an epoxy-containing acrylic resin, carboxylated activated carbon, carboxylated bentonite, and a catalyst were mixed and heated to 110 ° C for 9 h to obtain a modified activated carbon - bentonite composite material;

[0062] The mass ratio of the epoxy-containing acrylic resin, carboxylated activated carbon, carboxylated bentonite, and catalyst is 1:1:1:0.1.

[0063] Example 3

[0064] A method for decolorizing and deodorizing edible oil comprises the following steps:

[0065] S1. Under vacuum conditions, the crude edible oil product was heated to 85 ° C, and then 10% of the weight of the edible oil adsorbent was added to the crude edible oil product, heated to 105 ° C and stirred for 30 minutes, and filtered to obtain an intermediate product;

[0066] S2. The intermediate product was transferred to a deodorization tower, heated to 100°C, and directly introduced into the intermediate product at a pressure of 0.3MPa under vacuum conditions, accounting for 15% by weight of steam for deodorization for 3h to obtain decolorized and deodorized edible oil;

[0067] Wherein, the adsorbent is a modified activated carbon-bentonite composite material;

[0068] The preparation method of the adsorbent comprises the following steps:

[0069] L1. Epoxidized soybean oil, acrylic acid, and a polymerization inhibitor were mixed, heated to 110°C in the presence of a catalyst, and reacted for 2 h to obtain an intermediate product;

[0070] The mass ratio of the epoxidized soybean oil, acrylic acid, polymerization inhibitor and catalyst is 8:1:0.1:0.1;

[0071] L2. 10 g of the intermediate product, 10 ml of tetraethylene glycol diacrylate, 10 ml of n-propanol, 10 ml of 1,4-butanediol, 0.5 g of an initiator, and 200 ml of an emulsifier were mixed. After emulsification, 12 ml of polyglycidyl methacrylate was added and mixed evenly. The mixture was reacted at room temperature for 16 h, then heated to 70 ° C and continued to react for 16 h. The mixture was filtered and washed to obtain an acrylic resin containing an epoxy group.

[0072] Wherein, the emulsifier is a mixture of sodium lauryl sulfate, polyvinyl alcohol and water, the content of the sodium lauryl sulfate is 0.2wt%, and the content of the polyvinyl alcohol is 0.5wt%;

[0073] L3-1. The activated carbon was immersed in 7 mol / L nitric acid solution, heated to 80 ° C for 8h, washed, and dried to obtain carboxylated activated carbon;

[0074] L3-2. The bentonite was soaked in a 1.5 mol / L dopamine hydrochloride solution at a pH of 8.5, heated to 80 ° C for 8h, washed and dried to obtain polydopamine - bentonite;

[0075] L3-3. Using glycerol as a solvent, polydopamine - bentonite and potassium bicarbonate were mixed evenly (mass ratio of 1:5), heated to 180 ° C for 30 min, washed, and dried to obtain carboxylated bentonite;

[0076] L3-4. Under nitrogen, an epoxy-containing acrylic resin, carboxylated activated carbon, carboxylated bentonite, and a catalyst were mixed and heated to 110 ° C for 9 h to obtain a modified activated carbon - bentonite composite material;

[0077] The mass ratio of the epoxy-containing acrylic resin, carboxylated activated carbon, carboxylated bentonite, and catalyst is 1:1:1:0.1.

[0078] Comparative Example 1

[0079] A method for decolorizing and deodorizing edible oil. The difference between this comparative example and Example 1 is that step L2 is deleted, the acrylic resin containing epoxy groups is replaced by the intermediate product, and the other components and preparation methods are the same.

[0080] Comparative Example 2

[0081] A method for decolorizing and deodorizing edible oil. The difference between this comparative example and Example 1 is that the modified bentonite in this comparative example is replaced by a mixture of carboxylated activated carbon and carboxylated bentonite in a mass ratio of 1:1. Other components and preparation methods are the same.

[0082] Test Example 1

[0083] Decolorization rate test: The decolorization rate was determined by scanning the edible oil at all wavelengths using a UV-1900i ultraviolet-visible spectrophotometer to determine the maximum absorption wavelength. The absorbance of the edible oils of Example 1 and Comparative Examples 1-2 before and after decolorization and deodorization was then measured at this wavelength, and the decolorization rate was calculated.

[0084] Wherein, decolorization rate = (A0-A1) / A0×100%; A0 is the absorbance before refining; A1 is the absorbance after refining.

[0085] Odor test: Evaluate the edible oil after decolorization and deodorization of Example 1 and Comparative Examples 1-2.

[0086] The test results are shown in Table 1.

[0087] Table 1 Color and odor test results of edible oils of Example 1 and Comparative Examples 1-2

[0088]

[0089] As can be seen from Table 1, the edible oil decolorization and deodorization method of the present invention can effectively remove the odor and pigment of the edible oil, thereby improving the product quality of the edible oil.

[0090] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0091] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for decolorizing and deodorizing edible oil, characterized in that: The steps include: S1. Under vacuum conditions, an adsorbent is added to the crude edible oil product, heated and stirred, and filtered to obtain an intermediate product; S2. The intermediate product is transferred to a deodorization tower for deodorization to obtain decolorized and deodorized edible oil; Wherein, the adsorbent is a modified activated carbon-bentonite composite material; The modified activated carbon-bentonite composite material is obtained by reacting activated carbon, bentonite and acrylic resin containing epoxy groups.

2. The method for decolorizing and deodorizing edible oil according to claim 1, wherein: In step S1, the heating temperature is 100-110°C.

3. The method for decolorizing and deodorizing edible oil according to claim 1, wherein: In step S2, the deodorization temperature is 100-120°C.

4. The method for decolorizing and deodorizing edible oil according to claim 1, wherein: The added amount of the adsorbent is 10-15% of the weight of the edible oil.

5. The method for decolorizing and deodorizing edible oil according to claim 1, wherein: The preparation method of the adsorbent comprises the following steps: L1. The epoxidized soybean oil, acrylic acid and polymerization inhibitor are mixed and heated in the presence of a catalyst to obtain an intermediate product; L2 The intermediate product, tetraethylene glycol diacrylate, n-propanol, 1,4-butanediol, an initiator and an emulsifier were mixed, and after emulsification, polyglycidyl methacrylate was added and mixed uniformly. After the reaction at room temperature, the reaction was heated to obtain an acrylic resin containing an epoxy group; L3. Under the protection of inert gas, an epoxy-containing acrylic resin, carboxylated activated carbon, carboxylated bentonite, and a catalyst are mixed and heated to react to obtain a modified activated carbon-bentonite composite material.

6. The method for decolorizing and deodorizing edible oil according to claim 5, characterized in that: In step L1, the temperature of the heating reaction is 100-120°C.

7. The method for decolorizing and deodorizing edible oil according to claim 5, wherein: In step L2, the emulsifier is a mixture of sodium lauryl sulfate, polyvinyl alcohol and water.

8. The method for decolorizing and deodorizing edible oil according to claim 5, wherein: In step L2, the temperature of the heating reaction is 60-80°C.

9. The method for decolorizing and deodorizing edible oil according to claim 5, wherein: In step L3, the temperature of the heating reaction is 100-120°C.

10. The method for decolorizing and deodorizing edible oil according to claim 5, characterized in that: In step L3, the mass ratio of the carboxylated activated carbon to the carboxylated bentonite is 1-5:1-3.

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