Soap removal process of grease

Abstract

The invention discloses a grease desoaping method which comprises the following steps: a composite filter aid is added into grease, the composite filter aid comprises perlite and bentonite, and the granularity distribution of the perlite meets the following conditions: 20 [mu] m < = D50 < = 60 [mu] m, and D90 < = 150 [mu] m. According to the method, the soap content and acid value of the grease can be reduced, the shelf stability of the grease is improved, and meanwhile the filtering speed and the grease flavor of finished oil in the oil cleaning stage are not affected.

Description

Technical Field

[0001] The invention belongs to the field of oil processing, and in particular relates to a production process for oil soap removal. Background Art

[0002] In conventional oil refining process, after alkali refining and deacidification, the soap is separated and removed by the first centrifuge. Generally, the soap content in the oil is about 500 mg / kg. It needs to go through a water washing process to reduce the residual soap in the oil so that the subsequent decolorization process can proceed smoothly. The pollutants contained in the water washing wastewater are mainly neutral oil, sodium salts of fatty acids in the form of soap, organic phosphorus in the form of phospholipids, inorganic salts in the form of phosphoric acid, and dissolved inorganic acids, alkalis, pigments and other substances. Water washing wastewater is one of the main sources of pollution in oil refining, and the treatment of organic matter such as phosphorus has always been a problem that plagues the oil industry.

[0003] Reducing or eliminating the discharge of wastewater in the refining process by adopting new processes and technologies is a topic that my country's oil and fat industry has been studying. At present, there are two new technologies applied to the oil and fat alkali refining process in China: one is to use the washing wastewater of the alkali refining process to prepare alkali solution, and the alkali solution is then used in the alkali refining process to reduce the discharge of washing wastewater; the other is to use the adsorption desoaping process to replace the washing process to achieve the purpose of no wastewater discharge in the alkali refining process. Song Yunhua studied the method of removing soap from soybean oil with waste clay in the article (Research on Optimization of Waterless Soaping Process by Response Surface Methodology, Food Industry Science and Technology, Issue 23, 2012), and Zuo Qing added diatomaceous earth to remove phospholipids and soaps in the desoaped oil in the article (Transformation of Waterless Soaping Process in Oil and Fat Alkali Refining, Oil and Fat Processing, Volume 36, Issue 8, 2011), but both technologies currently have certain defects: the preparation of alkali solution from alkali refining wastewater has problems such as difficulty in controlling the soap and phosphorus content in the wastewater; adsorption desoaping has problems in adsorbent selection, filtration temperature, and control of soap and phosphorus content in degummed and deacidified oil.

[0004] Abroad, adsorption desoaping technology has been industrialized. The pre-complex decolorization technology launched by Germany's OHMI company has realized the water-free washing process in the refining process. India's Mecpro Heavy Engineering Company also has this technology, which mainly chooses diatomaceous earth as the adsorbent and adopts a vertical automatic slag discharge blade filter fully automatic filtration system. Cargill and ADM and other companies in the United States have promoted the waterless desoaping process of silica gel adsorption, but it is not particularly ideal and is not suitable for large-scale production. It consumes a lot of adsorbents and has relatively high requirements for crude oil varieties. It is suitable for desoaping oils with less colloidal impurities.

[0005] As an important indicator in the national standard for vegetable oils, acid value has always been the focus of vegetable oil producers. The main method to reduce the acid value in oils is chemical alkali refining, but this process requires the addition of excessive alkali solution and involves a high temperature environment, which will have an adverse effect on the flavor of the oil, so it is not suitable for the production of flavored vegetable oils.

[0006] In addition to chemical alkali refining, there are also reports in the literature on methods for reducing acid value by directly adding solid alkali or alkali solution to crude vegetable oil (such as crude peanut oil), all of which can effectively reduce the acid value. However, these methods do not mention the process for removing residual soap in the oil after deacidification, and the soap content has a greater impact on the quality of the refined oil.

[0007] Therefore, there is an urgent need in the art to provide a method and a composite filter aid that can reduce the acid value while removing the residual soap content. SUMMARY OF THE INVENTION

[0008] The inventors of the present invention have found that by controlling the contents of perlite and bentonite in the composite filter aid and the particle size of perlite, the soap content and acid value of the oil can be reduced, the shelf stability of the oil can be improved, and at the same time, the filtration rate and flavor of the refined oil in the clear oil stage are not affected.

[0009] In a first aspect of the present invention, there is provided a method for removing soap from oil, the method comprising adding a composite filter aid to the oil, the composite filter aid comprising perlite and bentonite, wherein the particle size distribution of perlite satisfies the condition: 20 μm ≤ D50 ≤ 60 μm, D90 ≤ 150 μm.

[0010] In one or more specific embodiments of the present invention, the soap removal method is preferably an anhydrous soap removal method.

[0011] In one or more specific embodiments of the present invention,

[0012] The amount of the composite filter aid added in the method is 0.3% - 1% of the oil weight.

[0013] In one or more specific embodiments of the present invention, based on the total mass of the composite filter aid, the proportion of perlite is 50 - 70%.

[0014] In one or more specific embodiments of the present invention, the oil is a liquid oil.

[0015] In one or more specific embodiments of the present invention, the oil is selected from one or more of walnut oil, soybean oil, corn oil, rice bran oil, sunflower seed oil, rapeseed oil, peanut oil, wheat germ oil, walnut oil, olive oil, linseed oil, sesame oil, tea oil, safflower seed oil, tiger nut oil, palm olein, rice bran oil, palm kernel olein, cottonseed oil, perilla seed oil, castor oil, coconut oil, olive oil, Chinese tallow tree seed oil, almond oil, apricot kernel oil, evening primrose oil, hazelnut oil, pumpkin seed oil, walnut oil, grape seed oil, borage seed oil, seabuckthorn seed oil, tomato seed oil, pumpkin seed oil, macadamia nut oil.

[0016] The second aspect of the present invention provides an oil refining method, which includes the degumming process described in the first aspect, and one or more selected from the steps of deacidification, degumming, decolorization, deodorization, and crystal cultivation.

[0017] In one or more specific embodiments of the present invention, the deacidification includes using an alkali refining deacidification method.

[0018] In one or more specific embodiments of the present invention, 0.1-0.4 wt% of sodium carbonate is added to the oil.

[0019] Preferably, 0.15-0.25 wt% of sodium carbonate is added to the oil.

[0020] In one or more specific embodiments of the present invention, the alkali refining is followed by a drying step.

[0021] In one or more specific embodiments of the present invention, the crystal cultivation includes cooling the oil mixed with the composite filter aid to 2°C to 18°C. Preferably, the crystal cultivation time is 4-20 h. After the crystal cultivation is completed, pressure filtration is carried out. Preferably, the pressure of the pressure filtration is 0.1-1.0 MPa, and more preferably, the pressure of the pressure filtration is 0.4-0.6 MPa.

[0022] In one or more specific embodiments of the present invention, the oil is a liquid oil.

[0023] In one or more specific embodiments of the present invention, the oil is selected from one or more of walnut oil, soybean oil, corn oil, rice bran oil, sunflower seed oil, rapeseed oil, peanut oil, wheat germ oil, walnut oil, olive oil, linseed oil, sesame oil, tea oil, safflower seed oil, tiger nut oil, palm olein, rice bran oil, palm kernel olein, cottonseed oil, perilla oil, castor oil, coconut oil, olive oil, Chinese tallow tree seed oil, almond oil, evening primrose oil, hazelnut oil, pumpkin seed oil, walnut oil, grape seed oil, borage oil, sea buckthorn oil, tomato seed oil, pumpkin seed oil, macadamia nut oil.

[0024] The third aspect of the present invention provides an oil, which is obtained by treating with the oil degumming method described in the first aspect of the present invention or the oil refining method described in the second aspect of the present invention.

[0025] The fourth aspect of the present invention provides an oil composition, which contains the oil described in the third aspect of the present invention.

[0026] The fifth aspect of the present invention provides a composite filter aid, which includes perlite and bentonite. The particle size distribution of the perlite satisfies the conditions: 20 μm ≤ D50 ≤ 60 μm, D90 ≤ 150 μm.

[0027] In one or more specific embodiments of the present invention, the proportion of perlite in the composite filter aid is 50-70%.

[0028] In one or more specific embodiments of the present invention, the proportion of bentonite in the composite filter aid is 30-50%.

[0029] In the sixth aspect of the present invention, there is provided the use of the oil degumming method described in the first aspect of the present invention in reducing the soap content in oil, reducing the acid value of oil and / or extending the shelf stability.

[0030] In the seventh aspect of the present invention, there is provided the use of a composite filter aid in reducing the soap content in oil, reducing the acid value of oil and / or extending the shelf stability. The composite filter aid comprises perlite and bentonite, wherein the particle size distribution of perlite satisfies the conditions: 20μm ≤ D50 ≤ 60μm, D90 ≤ 150μm.

[0031] In one or more specific embodiments of the present invention, the proportion of perlite in the composite filter aid is 50-70%. Detailed Description

[0032] To enable those skilled in the art to understand the features and effects of the present invention, the following provides a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used herein shall have the ordinary meaning understood by those skilled in the art for the present invention. In case of conflict, the definition in this specification shall prevail.

[0033] The theories or mechanisms described and disclosed herein, whether correct or incorrect, shall not limit the scope of the present invention in any way, that is, the content of the present invention can be implemented without being limited by any specific theory or mechanism.

[0034] In this article, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are only for the sake of brevity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be regarded as having covered and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0035] In this article, unless otherwise specified, the percentage refers to the mass percentage and the ratio refers to the mass ratio.

[0036] In this article, the sum of the percentage contents of the components of the composition is 100%.

[0037] In this text, when describing the embodiments or examples, it should be understood that it is not used to limit the present invention to these embodiments or examples. On the contrary, all alternatives, improvements, and equivalents of the methods and materials described in the present invention can be covered within the scope defined by the claims.

[0038] In this text, for the sake of concise description, not all possible combinations of all technical features in each embodiment or example are described. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each embodiment or example can be combined arbitrarily, and all possible combinations should be considered as the scope described in this specification.

[0039] The present invention discovers that by controlling the content of perlite and bentonite in the composite filter aid and the particle size of perlite, the soap content and acid value of the oil can be reduced, the shelf stability of the oil can be improved, and at the same time, the filtration rate and flavor of the refined oil in the clear oil stage are not affected. Thus, the present invention is completed.

[0040] The present invention provides an oil de - soaping method, which includes adding a composite filter aid to the oil, and the composite filter aid includes perlite and bentonite.

[0041] In one or more specific embodiments of the present invention, the de - soaping method is preferably an anhydrous de - soaping method.

[0042] In some embodiments, the particle size distribution of the perlite of the present invention satisfies the conditions: 20μm ≤ D50 ≤ 60μm, D90 ≤ 150μm.

[0043] In one or more embodiments, the added composite filter aid accounts for 0.3% - 1% of the oil weight.

[0044] In one or more embodiments, based on the total mass of the composite filter aid, the proportion of perlite is 50 - 70%.

[0045] In one or more embodiments, based on the total mass of the composite filter aid, the proportion of bentonite is 30 - 50%.

[0046] In some embodiments, the fineness of the bentonite of the present invention is more than 200 mesh, preferably 200 - 400 mesh.

[0047] The present invention provides a method for refining oil and fat, which method comprises the oil and fat soap removal step described herein and one or more selected from the steps of deacidification, degumming, decolorization, deodorization, and crystallization cultivation. It should be understood that, depending on the actual production situation and production purpose, one or more of the steps of deacidification, degumming, decolorization, deodorization, and crystallization cultivation may be omitted. Preferably, it comprises the oil and fat soap removal step described herein and one or more selected from the steps of deacidification, degumming, and crystallization cultivation. The process conditions for deacidification, degumming, and crystallization cultivation can be conventional process conditions in the art and can be adjusted according to the actual production situation.

[0048] The main purpose of deacidification (caustic refining) is to remove free fatty acids from the oil and fat, and at the same time remove some impurities such as pigments, phospholipids, hydrocarbons, and mucilage. The method of deacidification can be conventional in the art, such as caustic refining.

[0049] The process conditions for caustic refining can adopt the process conditions in "Bailey's Industrial Oil and Fat Products" (Volume VI), etc. In the present invention, 0.1-0.3 wt% of sodium carbonate, preferably 0.15-0.25 wt%, is added to the crude oil tank and mixed and stirred for 2-8 h; the sodium carbonate is preferably food-grade sodium carbonate; other processes for caustic refining can be conventional processes. For example, the reaction time for caustic refining can be 10-120 min, preferably 30-120 min; the addition amount of the caustic solution can be conventional in the art, for example, it can be 0.5-15%, 1-10% of the oil weight. Those skilled in the art can understand that the caustic added during caustic refining is divided into two parts: theoretical caustic and excess caustic. Generally, the amount of added caustic = 7.13×10-4×M oil×AV×(1 + excess caustic amount), the excess caustic amount can be 0-20%, and the amount of caustic solution = the amount of added caustic / the concentration of the caustic solution, where M oil refers to the oil weight and AV refers to the acid value. After the reaction of the caustic solution and the oil and fat is completed, centrifugation can obtain the neutralized oil. It should be understood that in the case where the degummed oil contains the solvent used in the oil extraction by the leaching method, the solvent can be removed after caustic refining, such as by evaporation. One of the features of the present invention is to control the acid value of the deacidified oil obtained by caustic refining within the range of 0-2 mg / g. Therefore, there are no special restrictions on the selection of the concentration, dosage, and reaction time of the caustic solution, as long as the acid value of the caustic-refined deacidified oil obtained is controlled within the above range.

[0050] After caustic refining and deacidification, dewaxing is usually carried out. One of the features of the present invention is anhydrous dewaxing. Specifically, a non-aqueous dewaxing medium is used for dewaxing. In the present invention, the inventive point lies in that the dewaxing medium is a composite filter aid containing perlite (50 - 70%) and bentonite (30 - 50%). The particle size distribution of perlite satisfies the conditions: 20μm ≤ D50 ≤ 60μm, D90 ≤ 150μm. Other processes for dewaxing can be conventional processes. For example, an appropriate amount of dewaxing medium can be added to the caustic-refined and deacidified oil. In the present invention, 0.3% - 1% of the dewaxing medium based on the weight of the caustic-refined and deacidified oil is added, as long as the particle size of perlite is controlled within the above range.

[0051] The fineness of bentonite is above 200 mesh, preferably 200 - 400 mesh.

[0052] Exemplary degumming includes filtering crude oil to remove solid impurities and then adding a degumming medium to degum the crude oil. The degumming medium can be a conventional degumming medium in the art, such as citric acid, phosphoric acid solution, and degummed lecithin. When using a degumming enzyme (such as PLA1 phospholipase), the reaction system is generally at 45 - 80°C for 2 - 8 h. The degumming medium is not less than 0.05 wt% of the weight of the crude oil and usually not more than 2 wt% of the weight of the crude oil. When using an acid, based on the total weight of the solution, the concentration of the acid is not less than 5 wt% and usually not more than 80 wt%, for example, it can be within the ranges of 5 - 65 wt%, 10 - 60 wt%, 20 - 50 wt%. Water can be added simultaneously. Usually, the amount of water is not less than 0.5 wt% of the weight of the crude oil; usually, the amount of water used in a single degumming step is not more than 30 wt% of the weight of the oil, for example, within the ranges of 0.5 - 20 wt%, 0.5 - 10 wt%, 5 - 25 wt%. The amount of water does not include the water in the degumming medium. After the reaction ends, the gum is separated to obtain degummed oil.

[0053] In some embodiments, PLA1 phospholipase is used to degum crude oil. The added mass of the phospholipase is 10 - 1000 mg / kg of the mass of the crude oil, the reaction temperature is 45 - 50°C, the reaction time is 4 - 6 h, the reaction pH value is 5 - 5.3, and after the reaction ends, the gum is separated to obtain degummed oil.

[0054] In some examples, the crystallization temperature is adjusted to 2 - 18°C, and the crystallization time is 4 - 20 h; at the same time, the crystallization temperature can be appropriately adjusted according to the difference in oil types. For example, pressed peanut oil has a low wax content, and its crystallization temperature is adjusted to 14°C - 18°C, and the crystallization time is more than 4 h. Preferably, the crystallization temperature is 16°C, and the crystallization time is 4 - 20 h. The process conditions for crystallization can be conventional process conditions in the art and can be adjusted according to the actual production situation.

[0055] In some embodiments, the crystallization oil is pressure-filtered. The pressure for pressure filtration is generally 0.1 - 1.0 MPa, preferably 0.4 - 0.6 MPa, and more preferably filtered at a pressure of 0.5 MPa. The process conditions for pressure filtration can be conventional process conditions in the art and can be adjusted according to the actual production situation.

[0056] The present invention also includes the oil and fat obtained by treating with the method described in any embodiment of the present invention.

[0057] In some embodiments, the soap content of the oil and fat obtained by treating with the method of the present invention is less than or equal to 50 ppm, preferably less than or equal to 45.82 ppm, and more preferably less than or equal to 42.17 ppm.

[0058] In some embodiments, the acid value of the oil and fat obtained by treating with the method of the present invention is less than or equal to 2.14 mg KOH / g, preferably less than or equal to 1.75 mg KOH / g, and more preferably less than or equal to 1.39 mg KOH / g.

[0059] In some embodiments, the peroxide value of the oil and fat obtained by treating with the method of the present invention is less than or equal to 0.91 ppm, preferably less than or equal to 0.78 ppm, and more preferably less than or equal to 0.64 ppm.

[0060] The present invention also provides a composite filter aid. The filter aid includes perlite and bentonite, wherein the particle size distribution of perlite satisfies the conditions: 20 μm ≤ D50 ≤ 60 μm, D90 ≤ 150 μm.

[0061] In some embodiments, the proportion of perlite in the composite filter aid is 50 - 70%.

[0062] In some embodiments, the proportion of bentonite in the composite filter aid is 30 - 50%.

[0063] In some embodiments, the fineness of bentonite is more than 200 mesh, preferably 200 - 400 mesh.

[0064] In some embodiments, the present invention also provides the application of the composite filter aid described in any embodiment herein in reducing the soap content in oil and fat, reducing the acid value of oil and fat, and / or extending the shelf stability.

[0065] In some embodiments, the present invention also provides a method for reducing the soap content in oil and fat, reducing the acid value of oil and fat, and / or extending the shelf stability. The method includes treating the oil and fat with the oil and fat soap removal method or the oil and fat refining method described in any embodiment herein.

[0066] The composite filter aid of the present invention and the foregoing method are applicable to the moderate processing of various oils and fats well-known in the art, and the oils and fats include but are not limited to walnut oil, soybean oil, corn oil, rice bran oil, sunflower seed oil, rapeseed oil, peanut oil, wheat germ oil, walnut oil, olive oil, linseed oil, sesame oil, camellia oil, safflower seed oil, cyperus esculentus oil, palm olein, rice bran oil, palm kernel olein, cottonseed oil, perilla seed oil, castor oil, coconut oil, olive oil, Chinese tallow tree seed oil, almond oil, apricot kernel oil, evening primrose oil, hazelnut oil, pumpkin seed oil, walnut oil, grape seed oil, borage seed oil, seabuckthorn seed oil, tomato seed oil, pumpkin seed oil, macadamia nut oil and other vegetable oils and animal oils or mixtures thereof. It should be understood that the "oil" mentioned in the present invention includes oil and / or fat, such as degummed oil, neutralized oil, dewaxed oil, decolorized oil and refined oil, etc., all of which include oil and / or fat.

[0067] The present invention has the following beneficial effects:

[0068] By controlling the contents of perlite and bentonite in the composite filter aid and the particle size of perlite, the present invention can reduce the soap content and acid value of oils and fats, improve the shelf stability of oils and fats, and at the same time do not affect the filtration speed and flavor of the refined oil in the clear oil stage.

[0069] The present invention will be further described below by way of specific examples. It should be understood that these examples are merely illustrative and not intended to limit the scope of the present invention. The methods and reagents used in the examples are conventional methods and reagents in the art unless otherwise specified.

[0070] Materials

[0071] Perlite: Purchased from Zhongnan Filter Aid Co., Ltd., Henan Province, and ground by a ball mill to obtain the required particle size.

[0072] Bentonite: Ningcheng Tianyu Bentonite Technology Co., Ltd., Inner Mongolia (fineness: 200 mesh).

[0073] Pressed peanut crude oil: Purchased from Yihai Kerry (Qingdao) Flavor Oils Co., Ltd.

[0074] Pressed sesame crude oil: Purchased from Yihai Kerry (Qingdao) Flavor Oils Co., Ltd.

[0075] Pressed rapeseed crude oil: Purchased from Yihai (Guanghan) Grain and Oil Feed Co., Ltd.

[0076] Silica gel adsorbent: SORBSIL R92, PQ Corporation, USA.

[0077] Detection methods

[0078] 1. Determination of soap content: Refer to GB / T 5533-2008 Cereals, oils and foodstuffs - Determination of soap content in vegetable oils.

[0079] 2. The method for evaluating the flavor is as follows: Randomly select 12 sensory evaluators to smell, and score the flavor preference respectively (0 - 10 points). The scoring criteria are: very dislike (1 point), dislike very much (2 points), dislike (3 points), dislike a little (4 points), neither like nor dislike (5 points), like slightly (6 points), like generally (7 points), like (8 points), like very much (9 points), like extremely (10 points). Finally, take the average value of the scores for the same oil, which is the final flavor score of the oil.

[0080] 3. The method for the shelf - life experiment is as follows: Put each oil sample into a transparent sealed container, ensure that the sample amount in each container is equal, store at room temperature, and try to avoid exposure to air and light. Sampling is carried out at 1 month, 3 months, and 6 months after the start of storage, and the peroxide value of the oil is measured.

[0081] 4. Determination of peroxide value: Refer to the first method in GB 5009.227 - 2016 National Food Safety Standard - Determination of peroxide value in foods.

[0082] 5. Determination of acid value: The acid value of edible vegetable oil < 3mg KOH / g; The determination of acid value refers to: the first method in GB 5009.229 - 2016 National Food Safety Standard - Determination of acid value in foods.

[0083] 6. Determination of perlite particle size distribution: Refer to GB / T 19077 - 2016 Particle size analysis - Laser diffraction method

[0084] 7. Determination of the flow rate of the filter press: Read and record the flowmeter on the discharge pipe of the filter press.

[0085] Example 1

[0086] Add 0.15wt% sodium carbonate to the pressed peanut crude oil tank with an acid value of 1.8mg KOH / g, mix and stir for 2h to obtain degummed oil. The measured soap content is 1934ppm and the acid value is 1.39mg KOH / g. At room temperature, add 0.3% compound filter aid to the above soap - containing degummed oil, in which perlite accounts for 70% (D50 = 55.11μm, D90 = 98.14μm) and bentonite accounts for 30%. Cool down to 16°C and crystallize for 4h. After the crystallization is completed, pump the peanut oil into a filter press (B10A220 / 1250 - UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5MPa to obtain finished peanut oil 1, and record the flow rate of the filtered oil.

[0087] After the pressure filtration is completed, 10 g of filter cake is taken within a thickness of 1 mm close to the filter cloth, added to 100 g of refined peanut oil with a soap content of 0, stirred at 100 rpm for 30 min, centrifuged at 4000 rpm for 5 min, and the supernatant oil is taken. The soap content of the supernatant oil is measured to be 183 ppm.

[0088] Example 2

[0089] 0.25 wt% sodium carbonate is added to the pressed peanut crude oil tank with an acid value of 2.7 mg KOH / g, mixed and stirred for 2 h to obtain degummed oil. The measured soap content is 3327 ppm and the acid value is 1.97 mg KOH / g. At room temperature, 0.5% composite filter aid is added to the above-mentioned soap-containing degummed oil, with perlite accounting for 50% (D50 = 25.37 μm, D90 = 50.10 μm) and bentonite accounting for 50%. The temperature is lowered to 16 °C and crystallization is carried out for 4 h. After the crystallization is completed, the peanut oil is pumped into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filtered at a pressure of 0.5 MPa to obtain finished peanut oil 2, and the flow rate of the filtered oil is recorded.

[0090] Example 3

[0091] 0.2 wt% sodium carbonate is added to the pressed peanut crude oil tank with an acid value of 2.3 mg KOH / g, mixed and stirred for 2 h to obtain degummed oil. The measured soap content is 2539 ppm and the acid value is 1.75 mg KOH / g. At room temperature, 0.4% composite filter aid is added to the above-mentioned soap-containing degummed oil, with perlite accounting for 60% (D50 = 36.40 μm, D90 = 60.93 μm) and bentonite accounting for 40%. The temperature is lowered to 16 °C and crystallization is carried out for 4 h. After the crystallization is completed, the peanut oil is pumped into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filtered at a pressure of 0.5 MPa to obtain finished peanut oil 3, and the flow rate of the filtered oil is recorded.

[0092] Example 4

[0093] 0.25 wt% sodium carbonate is added to the pressed sesame crude oil tank with an acid value of 2.9 mg KOH / g, mixed and stirred for 2 h to obtain degummed oil. The measured soap content is 3431 ppm and the acid value is 2.14 mg KOH / g. At room temperature, 0.5% composite filter aid is added to the above-mentioned soap-containing degummed oil, with perlite accounting for 50% (D50 = 25.37 μm, D90 = 50.10 μm) and bentonite accounting for 50%. The temperature is lowered to 4 °C and crystallization is carried out for 4 h. After the crystallization is completed, the sesame oil is pumped into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filtered at a pressure of 0.4 MPa to obtain finished sesame oil 1, and the flow rate of the filtered oil is recorded.

[0094] Example 5

[0095] Add 0.15 wt% sodium carbonate to the pressed rapeseed crude oil tank with an acid value of 1.7 mg KOH / g, mix and stir for 2 h to obtain degummed oil. The measured soap content is 1905 ppm and the acid value is 1.30 mg KOH / g. At room temperature, add 0.3% composite filter aid to the above soap-containing degummed oil, where perlite accounts for 70% (D50 = 55.11 μm, D90 = 98.14 μm) and bentonite accounts for 30%. Cool down to 5°C and crystallize for 4 h. After crystallization is completed, pump the rapeseed oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.6 MPa to obtain finished rapeseed oil 1, and record the filtered oil flow rate.

[0096] Comparative Example 1

[0097] Add 0.15 wt% sodium carbonate to the pressed peanut crude oil tank with an acid value of 1.8 mg KOH / g, mix and stir for 2 h to obtain degummed oil. The measured soap content is 1934 ppm and the acid value is 1.39 mg KOH / g. At room temperature, add 0.3% composite filter aid to the above soap-containing degummed oil, where perlite accounts for 70% (D50 = 104.40 μm, D90 = 247.50 μm) and bentonite accounts for 30%. Cool down to 16°C and crystallize for 4 h. After crystallization is completed, pump the peanut oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5 MPa to obtain finished peanut oil 4, and record the filtered oil flow rate.

[0098] After filtration, take 10 g of filter cake within 1 mm thickness near the filter cloth, add it to 100 g of refined peanut oil with a soap content of 0, stir at 100 rpm for 30 min, and then centrifuge at 4000 rpm for 5 min to take the supernatant oil. The measured soap content of the supernatant oil is 2449 ppm.

[0099] Comparative Example 2

[0100] Add 0.25 wt% sodium carbonate to the pressed peanut crude oil tank with an acid value of 2.7 mg KOH / g, mix and stir for 2 h to obtain degummed oil. The measured soap content is 3327 ppm and the acid value is 1.97 mg KOH / g. At room temperature, add 0.2% composite filter aid to the above soap-containing degummed oil, where perlite accounts for 50% (D50 = 25.37 μm, D90 = 50.10 μm) and bentonite accounts for 50%. Cool down to 16°C and crystallize for 4 h. After crystallization is completed, pump the peanut oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5 MPa to obtain finished peanut oil 5, and record the filtered oil flow rate.

[0101] Comparative Example 3

[0102] Add 0.2 wt% sodium carbonate to the pressed peanut crude oil tank with an acid value of 2.3 mg KOH / g, mix and stir for 2 h to obtain degummed oil. Measure its soap content to be 2539 ppm and the acid value to be mg KOH / g. At room temperature, add 0.4% composite filter aid to the above-mentioned soap-containing degummed oil, where perlite accounts for 60% (D50 = 12.63 μm, D90 = 42.27 μm) and bentonite accounts for 40%. Cool down to 16 °C and carry out crystal cultivation for 4 h. After the crystal cultivation is completed, pump the peanut oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5 MPa to obtain finished peanut oil 6, and record the flow rate of the filtered oil.

[0103] Comparative Example 4

[0104] Add 0.2 wt% sodium carbonate to the pressed peanut crude oil tank with an acid value of 2.3 mg KOH / g, mix and stir for 2 h to obtain degummed oil. Measure its soap content to be 2539 ppm and the acid value to be 1.75 mg KOH / g. At room temperature, add 0.4% composite filter aid to the above-mentioned soap-containing degummed oil, where perlite accounts for 80% (D50 = 36.40 μm, D90 = 60.93 μm) and bentonite accounts for 20%. Cool down to 16 °C and carry out crystal cultivation for 4 h. After the crystal cultivation is completed, pump the peanut oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5 MPa to obtain finished peanut oil 7, and record the flow rate of the filtered oil.

[0105] Comparative Example 5

[0106] Add 0.2 wt% sodium carbonate to the pressed peanut crude oil tank with an acid value of 2.3 mg KOH / g, mix and stir for 2 h to obtain degummed oil. Measure its soap content to be 2539 ppm and the acid value to be 1.75 mg KOH / g. At room temperature, add 0.4% composite filter aid to the above-mentioned soap-containing degummed oil, where perlite accounts for 20% (D50 = 36.40 μm, D90 = 60.93 μm) and bentonite accounts for 80%. Cool down to 16 °C and carry out crystal cultivation for 4 h. After the crystal cultivation is completed, pump the peanut oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5 MPa to obtain finished peanut oil 8, and record the flow rate of the filtered oil.

[0107] Comparative Example 6

[0108] Add 0.15 wt% sodium carbonate to the pressed peanut crude oil tank with an acid value of 1.8 mg KOH / g, mix and stir for 2 h to obtain degummed oil. The measured soap content is 1934 ppm and the acid value is 1.39 mg KOH / g. At room temperature, add 0.3% silica gel adsorbent (SORBSIL R92, PQ Corporation, USA) to the above degummed oil containing soap. Cool down to 16 °C and crystallize for 4 h. After crystallization is completed, pump the peanut oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5 MPa to obtain finished peanut oil 9, and record the flow rate of the filtered oil.

[0109] Comparative Example 7

[0110] Add 0.25 wt% sodium hydroxide to the pressed peanut crude oil tank with an acid value of 2.7 mg KOH / g, mix and stir for 2 h to obtain degummed oil. The measured soap content is 3573 ppm and the acid value is 2.01 mg KOH / g. At room temperature, add 0.5% composite filter aid to the above degummed oil containing soap, where perlite accounts for 50% (D50 = 25.37 μm, D90 = 50.10 μm) and bentonite accounts for 50%. Cool down to 16 °C and crystallize for 4 h. After crystallization is completed, pump the peanut oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5 MPa to obtain finished peanut oil 10, and record the flow rate of the filtered oil.

[0111] Comparative Example 8

[0112] Add 0.25 wt% calcium hydroxide to the pressed peanut crude oil tank with an acid value of 2.7 mg KOH / g, mix and stir for 2 h to obtain degummed oil. The measured soap content is 3539 ppm and the acid value is 2.04 mg KOH / g. At room temperature, add 0.5% composite filter aid to the above degummed oil containing soap, where perlite accounts for 50% (D50 = 25.37 μm, D90 = 50.10 μm) and bentonite accounts for 50%. Cool down to 16 °C and crystallize for 4 h. After crystallization is completed, pump the peanut oil into a filter press (B10A220 / 1250-UK, Hangzhou Xingyuan Environmental Protection Equipment Co., Ltd.) and filter at a pressure of 0.5 MPa to obtain finished peanut oil 11, and record the flow rate of the filtered oil.

[0113] In the above examples and comparative examples, the soap content, flavor evaluation data of the refined oil, and the oil output flow rate of the filter press are listed in Table 1 below.

[0114] Table 1. Acid value, soap content, flavor evaluation data of oils, and oil output flow rate of the filter press

[0115]

[0116] It can be seen from the results in Table 1 that in this process, the degumming effect of the pressed crude oil is affected by multiple factors, specifically manifested as follows:

[0117] 1. If the perlite particles in the formula are too coarse, it will cause the filtration speed to slow down, and the soap content in the refined oil after filtration will increase, which will have a negative impact on the flavor of the refined oil. On the contrary, if the perlite particles in the formula are too fine, it will also lead to a slowdown in the filtration speed. By comparing Example 1 with Comparative Example 1, it can be known that compared with the perlite used in Comparative Example 1, the perlite used in Example 1 can effectively avoid the increase in the soap content of the refined oil and the decrease in the filtration rate caused by the accumulation of soap on the surface of the filter cloth.

[0118] 2. If the proportion of perlite in the formula is too high, it will cause the soap content in the refined oil after filtration to increase; on the contrary, if the proportion of perlite in the formula is too low, it will cause a significant slowdown in the filtration speed.

[0119] 3. If the overall addition amount of the filter aid is too low, it will simultaneously cause the filtration speed to slow down and the soap content of the refined oil after filtration to increase.

[0120] In addition, when degumming the crude oil, sodium carbonate is preferably used as the alkali. If other common alkalis are used, it will also have a great impact on the subsequent degumming effect, specifically manifested as follows: if sodium hydroxide is used, it will have a great impact on the flavor of the oil; if calcium hydroxide is used, it will cause a significant decrease in the filtration speed.

[0121] In the above examples and comparative examples, the shelf-life experimental data of the refined oil are listed in Table 2 below.

[0122] Table 2. Shelf-life experimental data of refined oil

[0123]

[0124]

[0125] It can be seen from the results in Table 2 that there is a correlation between the soap content of the oil and the increase in peroxide value during the shelf life. The refined oil with a low soap content has higher shelf stability.

Claims

1. A method for degumming oil and fat, characterized in that, The method includes adding a composite filter aid to the oil or fat, and the composite filter aid includes perlite and bentonite, wherein the particle size distribution of the perlite satisfies the conditions: 20μm ≤ D50 ≤ 60μm, D90 ≤ 150μm.

2. The method according to claim 1, wherein The degumming method has one or more of the following characteristics: In the method, the added composite filter aid accounts for 0.3% - 1% of the oil weight; and / or Based on the total mass of the composite filter aid, the proportion of the perlite is 50 - 70%; and / or The oil or fat is liquid oil or fat; and / or The oil or fat is selected from one or more of walnut oil, soybean oil, corn oil, rice bran oil, sunflower seed oil, rapeseed oil, peanut oil, wheat germ oil, walnut oil, olive oil, linseed oil, sesame oil, tea oil, safflower seed oil, tiger nut oil, palm olein, rice bran oil, palm kernel olein, cottonseed oil, perilla seed oil, castor oil, coconut oil, olive oil, Chinese tallow tree seed oil, almond oil, apricot kernel oil, evening primrose oil, hazelnut oil, pumpkin seed oil, walnut oil, grape seed oil, borage seed oil, seabuckthorn seed oil, tomato seed oil, pumpkin seed oil, macadamia nut oil.

3. A method for refining oil and fat, characterized in that, The method includes the degumming method according to claim 1 or 2, and one or more selected from the steps of deacidification, degumming, decolorization, deodorization, and crystal cultivation.

4. The method according to claim 3, characterized in that The deacidification includes using the caustic refining method for deacidification. Optionally, 0.1 - 0.4wt% sodium carbonate is added to the oil or fat. Preferably, 0.15 - 0.25wt% sodium carbonate is added to the oil or fat. Optionally, the caustic refining is followed by a drying step.

5. The method according to claim 3 or 4, characterized in that The crystal cultivation includes cooling the oil or fat mixed with the composite filter aid to 2°C - 18°C. Preferably, the crystal cultivation time is 4 - 20h. After the crystal cultivation is completed, pressure filtration is carried out. Preferably, the pressure of the pressure filtration is 0.1 - 1.0MPa. More preferably, the pressure of the pressure filtration is 0.4 - 0.6MPa.

6. The oil or fat obtained by using the method according to any one of claims 1 - 5.

7. An oil or fat composition containing the oil or fat obtained by using the method according to any one of claims 1 - 5.

8. The grease according to claim 6, characterized in that, The oil or fat satisfies one or more of the following conditions: The soap content of the oil or fat is less than or equal to 50ppm, preferably less than or equal to 45.82ppm, more preferably less than or equal to 42.17ppm; and / or The acid value of the oil or fat is less than or equal to 2.14mg KOH / g, preferably less than or equal to 1.75mg KOH / g, more preferably less than or equal to 1.39mg KOH / g; and / or The peroxide value of the oil or fat is less than or equal to 0.91ppm, preferably less than or equal to 0.78ppm, more preferably less than or equal to 0.64ppm.

9. A composite filter aid, characterized in that, The composite filter aid has one or more of the following characteristics: The filter aid includes perlite and bentonite, wherein the particle size distribution of the perlite satisfies the conditions: 20μm ≤ D50 ≤ 60μm, D90 ≤ 150μm; In the composite filter aid, the proportion of the perlite is 50 - 70%.

10. Use of the method according to any one of claims 1 to 5 or the composite filter aid according to claim 9 in reducing the soap content in oil or fat, reducing the acid value of oil or fat and / or extending the shelf stability.

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