Fish oil and its refining processing method

Abstract

The present invention relates to the field of food processing technology, and discloses a fish oil and a refining method thereof. The method comprises: (1) first mixing crude fish oil with water, a complex enzyme, and a chelating agent to obtain a mixed material; the complex enzyme is a combination of protease, phospholipase, and lipase; (2) sequentially separating and washing the mixed material to obtain an intermediate material I; (3) sequentially subjecting the intermediate material I to a first adsorption decolorization, a second adsorption decolorization, and a third adsorption decolorization to obtain an intermediate material II; the adsorption material I in the first adsorption decolorization comprises silica gel; the adsorption material II in the second adsorption decolorization is bleaching clay; and the adsorption material III in the third adsorption decolorization is activated carbon; (4) deodorizing the intermediate material II to obtain a fish oil product. The method provided by the present invention can effectively remove impurities in crude fish oil, retain a high rate of beneficial accompaniments in fish oil, and effectively control the generation of harmful substances in the production process.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, in particular to fish oil and a refining method thereof. Background Art

[0002] Fish oil is rich in ultra-long carbon-chain polyunsaturated fatty acids such as DHA and EPA, which are beneficial to human health, and is widely used in daily food and health food.

[0003] Crude fish oil is typically extracted through physical separation methods such as hot pressing or water substitution. Crude fish oil typically has a dark color, a fishy odor, and contains a certain amount of water, mechanical impurities, protein, phospholipids, and mineral salts. Crude fish oil undergoes a series of refining or separation and purification processes before it can be used in food or medical nutritional preparations. The refining process typically includes several steps: degumming, alkali refining, freeze separation, bleaching, and deodorization.

[0004] Degumming is the first step in fish oil refining. Its purpose is to remove the gelatinous components and mechanical impurities contained in crude fish oil. These gelatinous components mainly include phospholipids and proteins. Currently, there are three main degumming methods commonly used: water degumming, acid degumming, and enzymatic degumming.

[0005] Hydration degumming is rarely used in fish oil and is mainly applicable to vegetable oils. When the content of non-hydratable phospholipids is too high, the efficiency of hydration degumming will be seriously reduced.

[0006] Acid degumming refers to the addition of a certain proportion of inorganic or organic acid, generally phosphoric acid, sulfuric acid, citric acid, etc. The oil-soluble non-hydratable phospholipids in the crude fish oil are treated with acid to become hydrated phospholipids, which are then flocculated and agglomerated into the aqueous phase and removed by precipitation or centrifugal separation. Therefore, the removal efficiency is higher, but this method is prone to cause certain environmental pollution.

[0007] Enzymatic degumming usually refers to adding a certain amount of phospholipase, using the hydrolysis or decomposition effect of phospholipase on phospholipids, decomposing them into hydrophilic phospholipid derivatives or allowing the phospholipid groups to decompose and release, thereby entering the water phase for removal. Compared with the above-mentioned hydration degumming and acid degumming, enzymatic degumming has the advantages of energy saving and environmental protection, and has certain advantages in large-scale fish oil refining plants.

[0008] Alkali refining generally refers to the process of adding a certain proportion of alkaline solution to degummed or undegummed fish oil to neutralize acidic substances such as free fatty acids. The added alkali solution is usually an aqueous sodium hydroxide solution. Alkali refining can remove a large amount of free fatty acids and phospholipids, but it also has certain limitations. For example, during the alkali refining process, a certain amount of soap stock will be formed, and the soap stock will carry over the neutral oil and cause a large loss. Of course, the added sodium hydroxide will also cause certain environmental impact problems. In addition, some fat-soluble beneficial substances contained in fish oil, such as vitamins A, D, K and squalene, are also easily inactivated or decomposed under alkaline conditions or carried over by soap stock and lost, resulting in nutrient loss.

[0009] Decolorization refers to the use of the adsorption and catalytic reduction effects of adsorption decolorizers to adsorb and remove pigments, heavy metals, residual phospholipids and proteins contained in fish oil. Decolorizers are generally activated carbon or activated white clay.

[0010] Deodorization refers to the removal of some volatile substances, oxidation products or secondary oxidation products, and heat-sensitive pigments that give rise to odor under high temperature and vacuum conditions. Deodorization is always accompanied by high temperature conditions. Long-term high temperature conditions will cause the loss of ultra-long carbon chain polyunsaturated fatty acids and fat-soluble beneficial accompaniments in fish oil, and will also produce some harmful substances, such as trans fatty acids, 3-monochloropropane-1,2-diol fatty acidesters (3-MCPD), glycidyl esters, etc.

[0011] Currently, a series of solutions to the problems existing in the above-mentioned fish oil refining process have been reported. For example, CN109593606A discloses a processing process for deep-sea fish oil with a high DHA content. This solution uses special food-grade silica gel for deodorization, which solves the problem of the specific odor of activated white clay produced by the use of activated white clay in traditional processes. In addition, this process does not require high temperatures, thus avoiding the destruction of the effective ingredients in the fish oil. However, the process still undergoes alkali refining in the early stage, which still poses problems of contamination and loss of neutral oil and beneficial accompaniments of the oil. In addition, the analysis, detection, verification and evaluation of the residual harmful substances are not involved.

[0012] CN107502448A discloses a process for deacidification using plasma adsorption, which has the advantages of simple process, easy control, high efficiency, less pollution, and no destruction of effective nutrients in fish oil, but does not involve the optimization of processes such as deodorization of fish oil after deacidification, and there are currently no large-scale industrial application cases. CN109234007A discloses a method for degumming and decolorizing fish oil, but this method requires the addition of a certain amount of organic solvent, which poses certain safety risk challenges and certain environmental impacts. CN118146866A discloses a method for preparing refined deep-sea fish oil with repair function. This solution uses a composite protease to extract fish oil, but does not involve the use of a composite enzyme for degumming in the subsequent fish oil refining process. Summary of the Invention

[0013] The purpose of the present invention is to solve the problems existing in the fish oil refining processing method of the prior art, such as low impurity removal rate, environmental unfriendliness, low retention rate of beneficial accompaniments of fish oil, high content of harmful substances such as heavy metals, and poor control of the generation of harmful substances in the production process.

[0014] In order to achieve the above object, the first aspect of the present invention provides a method for refining fish oil, the method comprising:

[0015] (1) Crude fish oil is first mixed with water, a complex enzyme, and a complexing agent to obtain a mixed material; the crude fish oil contains phosphorus, protein, pigment, vitamin A, vitamin D3, vitamin K1, and squalene, and has an acid value higher than 1 mg KOH / g; relative to 100 parts by weight of the crude fish oil, the amount of the water is 5-15 parts by weight, the amount of the complex enzyme is 0.01-0.06 parts by weight, and the amount of the complexing agent is 0.0005-0.002 parts by weight; the complex enzyme is a combination of protease, phospholipase, and lipase in a mass ratio of 1:2-4:1.5-5;

[0016] (2) Separating and washing the mixed material in sequence to obtain an intermediate material I;

[0017] (3) subjecting the intermediate material I to a first adsorption decolorization, a second adsorption decolorization, and a third adsorption decolorization in sequence to obtain an intermediate material II; the adsorption material I in the first adsorption decolorization comprises silica gel; the adsorption material II in the second adsorption decolorization is bleaching clay; and the adsorption material III in the third adsorption decolorization is activated carbon;

[0018] (5) Deodorizing the intermediate material II to obtain a fish oil product; wherein the fish oil product has a phosphorus residual content of not more than 5 mg / kg, a protein removal rate of not less than 60%, an acid value of not more than 1 mg KOH / g, a glycidyl ester of not more than 100 μg / kg, a 3-chloropropane ester of not more than 200 μg / kg, a vitamin A retention rate of not less than 70%, a vitamin D3 retention rate of not less than 50%, a vitamin K1 retention rate of not less than 45%, and a squalene retention rate of not less than 57%.

[0019] The second aspect of the present invention provides a fish oil product prepared by the method described in the first aspect.

[0020] Compared with the prior art, the technical solution provided by the present invention has at least the following advantages:

[0021] (1) The fish oil refining method provided by the present invention does not require an alkali refining process. The method of the present invention can more effectively remove colloid components such as phospholipids and proteins in crude fish oil, and does not cause environmental pollution, loss of neutral oil, and loss of beneficial accompaniments of fish oil. The beneficial accompaniments of fish oil (e.g., vitamin A, vitamin D, vitamin K, squalene) can be efficiently retained, significantly improving the quality of refined fish oil.

[0022] (2) The method provided by the present invention can significantly increase the Omega-3 fatty acid content of refined fish oil;

[0023] (3) The method provided by the present invention can ensure the sufficient removal of pigments and other substances through a specific three-step adsorption decolorization process, and the treatment time is short and high temperature is not required, thereby avoiding the deterioration of fish oil caused by long-term high-temperature treatment and improving the quality of fish oil;

[0024] (4) The present invention provides a refining process that can maintain the content of 3-chloropropanediol (3-MCPD) and glycidyl ester in the obtained fish oil at a lower level;

[0025] (5) The fish oil obtained by the present invention meets the food safety standards of China, the European Union and other countries, and has extremely high commercial application value;

[0026] (6) The refining processing method provided by the present invention can achieve the refining of fish oil by combining composite enzyme degumming, three-step adsorption decolorization and appropriate temperature deodorization without using complicated processes. It is highly environmentally friendly, low in cost and highly universal. DETAILED DESCRIPTION

[0027] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0028] As mentioned above, the first aspect of the present invention provides a method for refining fish oil, the method comprising:

[0029] (1) Crude fish oil is first mixed with water, a complex enzyme, and a complexing agent to obtain a mixed material; the crude fish oil contains phosphorus, protein, pigment, vitamin A, vitamin D3, vitamin K1, and squalene, and has an acid value higher than 1 mg KOH / g; relative to 100 parts by weight of the crude fish oil, the amount of the water is 5-15 parts by weight, the amount of the complex enzyme is 0.01-0.06 parts by weight, and the amount of the complexing agent is 0.0005-0.002 parts by weight; the complex enzyme is a combination of protease, phospholipase, and lipase in a mass ratio of 1:2-4:1.5-5;

[0030] (2) Separating and washing the mixed material in sequence to obtain an intermediate material I;

[0031] (3) subjecting the intermediate material I to a first adsorption decolorization, a second adsorption decolorization, and a third adsorption decolorization in sequence to obtain an intermediate material II; the adsorption material I in the first adsorption decolorization comprises silica gel; the adsorption material II in the second adsorption decolorization is bleaching clay; and the adsorption material III in the third adsorption decolorization is activated carbon;

[0032] (5) Deodorizing the intermediate material II to obtain a fish oil product; wherein the fish oil product has a phosphorus residual content of not more than 5 mg / kg, a protein removal rate of not less than 60%, an acid value of not more than 1 mg KOH / g, a glycidyl ester of not more than 100 μg / kg, a 3-chloropropane ester of not more than 200 μg / kg, a vitamin A retention rate of not less than 70%, a vitamin D3 retention rate of not less than 50%, a vitamin K1 retention rate of not less than 45%, and a squalene retention rate of not less than 57%.

[0033] Preferably, the crude fish oil contains 3-150 mg / kg of phosphorus, 0.1-1% of protein, 1-10 mg KOH / g of acid value, 20-300 μg / 100 g of vitamin A, 10-200 μg / 100 g of vitamin D3, 5-50 μg / 100 g of vitamin K1, and 50-400 mg / kg of squalene.

[0034] Preferably, the fish oil product has a phosphorus residue content of no more than 5 mg / kg, a protein removal rate of no less than 60%, an acid value of no more than 1 mg KOH / g, a plasticizer DBP of no more than 0.3 mg / kg, a plasticizer DEHP of no more than 0.5 mg / kg, a plasticizer DINP of no more than 5 mg / kg, contains almost no trans fatty acids, has a heavy metal residue content below the detection limit, glycidyl esters of no more than 100 μg / kg, 3-chloropropanol esters of no more than 200 μg / kg, saturated hydrocarbon mineral oils and polyolefin oligomers of no more than 5 mg / kg, aromatic hydrocarbon mineral oils of no more than 1 mg / kg, a vitamin A retention rate of no less than 70%, a vitamin D3 retention rate of no less than 50%, a vitamin K1 retention rate of no less than 45%, and a squalene retention rate of no less than 57%.

[0035] Preferably, in step (1), the first mixing conditions include: temperature of 35-50° C., time of 120-360 min, and stirring speed of 200-600 rpm.

[0036] It should be noted that, in the present invention, in order to make the first mixing more complete, high-speed shearing of the materials may be performed before the first mixing.

[0037] Preferably, relative to 100 parts by weight of crude fish oil, the amount of water is 5-8 parts by weight, the amount of the complex enzyme is 0.03-0.05 parts by weight, and the amount of the complexing agent is 0.001-0.002 parts by weight.

[0038] Preferably, the complexing agent is selected from at least one of ethylenediaminetetraacetic acid (EDTA), citric acid, and silicate.

[0039] More preferably, the complex enzyme is a combination of protease, phospholipase, and lipase in a mass ratio of 1:3-4:4-5. The inventors have found that under this preferred embodiment, colloid components such as phospholipids and proteins in crude fish oil can be better removed without causing loss of neutral oil and beneficial concomitants of the fish oil, while significantly increasing the omega-3 fatty acid content of the refined fish oil.

[0040] Preferably, the protease is selected from at least one of papain, pepsin, trypsin and bromelain.

[0041] More preferably, the protease is papain.

[0042] Preferably, the phospholipase is selected from at least one of phospholipase A1, phospholipase A2, and phospholipase C.

[0043] More preferably, the phospholipase is phospholipase A1.

[0044] Preferably, the lipase is at least one selected from the group consisting of lipases derived from Candida antarctica, Fusarium oxysporum, Thermomyces lanuginosus, Rhizopus miehei, Fusarium luteum, Fusarium heterosporum, Aspergillus niger var. tubingensis, and Fusarium oxysporum.

[0045] More preferably, the lipase is a lipase derived from Candida antarctica.

[0046] The present invention creatively discovered that when the above preferred composite enzyme type is used to degumming crude fish oil, the degumming efficiency is better and the obtained fish oil product is of higher quality.

[0047] Preferably, in step (2), the separation is performed using a disc centrifuge, and the mixture is heated to 75-95° C. before separation.

[0048] Preferably, in step (2), the method further comprises:

[0049] S1, washing the separated oil phase material for the first time in a first aqueous solution to obtain a first material; the pH value of the first aqueous solution is 5.1-6.9;

[0050] SII, washing the first material a second time in a second aqueous solution to obtain intermediate material I; the pH value of the second aqueous solution is 7.1-7.8. Through inventive research, the present inventors discovered that the preferred water washing method provided by the present invention can better remove the majority of chlorides in fish oil, significantly reduce the formation of 3-MCPD, and also control glycidyl esters to a lower level, thus avoiding the long-term repeated washing process in traditional water washing processes that leads to significant loss of glycerides and increased oxidation.

[0051] It should be noted that the present invention has no special requirements for the pH adjustment method of the first aqueous solution and the second aqueous solution. Conventional adjustment methods in the field can be used. The present invention will not be described in detail here, and those skilled in the art should not understand it as a limitation of the present invention.

[0052] Preferably, the amount of the first aqueous solution is 5-20 parts by weight relative to 100 parts by weight of the oil phase material, more preferably 10-15 parts by weight.

[0053] Preferably, the conditions for the first water washing include: a temperature of 80-100° C. and a time of 10 min-30 min.

[0054] Preferably, the amount of the second aqueous solution is 3-20 parts by weight, more preferably 5-15 parts by weight, relative to 100 parts by weight of the oil phase material.

[0055] More preferably, the conditions for the second water washing include: a temperature of 80-100° C. and a time of 10 min-30 min.

[0056] Preferably, the adsorption material I further comprises water, and relative to 100 parts by weight of the intermediate material I, the amount of the silicone gel is 0.1-2 parts by weight, and the amount of the water is 0.1-2 parts by weight.

[0057] More preferably, the temperature of the first adsorption decolorization is 50-98° C. and the time is 10-30 min.

[0058] Preferably, in the second adsorption decolorization, the amount of the bleaching clay is 0.1-5 parts by weight relative to 100 parts by weight of the intermediate material I.

[0059] More preferably, the amount of the bleaching clay is 0.5-3 parts by weight.

[0060] More preferably, the temperature of the second adsorption decolorization is 50-98° C. and the time is 10-30 min.

[0061] Preferably, in the third adsorption decolorization, the amount of the activated carbon used is 0.1-5 parts by weight relative to 100 parts by weight of the intermediate material I.

[0062] More preferably, the amount of the activated carbon is 0.3-3 parts by weight.

[0063] More preferably, the temperature of the third adsorption decolorization is 50-98° C. and the time is 10-30 min.

[0064] It should be noted that in the present invention, the first adsorption decolorization, the second adsorption decolorization and the third adsorption decolorization are all carried out by mixing and stirring the material with the adsorption material for adsorption decolorization, and then filtering to obtain the intermediate material II; the filter material for filtration is the same as the material for the adsorption decolorization; optionally, in order to obtain a fish oil product with higher quality, cyclic stirring and adsorption decolorization can be selected multiple times.

[0065] Preferably, in step (5), the deodorization is carried out in a deodorization tower, and the deodorization conditions include: a temperature of 195-210° C. and a time of 10-30 min.

[0066] It should be noted that there are no special requirements for the deodorizing tower used in the present invention. The operations during the deodorizing process can be carried out according to the conventional methods in the art. The present invention will not be described in detail here, and those skilled in the art should not understand it as a limitation to the present invention.

[0067] As described above, the second aspect of the present invention provides a fish oil product prepared by the method described in the first aspect; the fish oil product has a phosphorus residual content of no more than 5 mg / kg, a protein removal rate of no less than 60%, an acid value of no more than 1 mg KOH / g, a glycidyl ester of no more than 100 μg / kg, a 3-chloropropanol ester of no more than 200 μg / kg, a vitamin A retention rate of no less than 70%, a vitamin D3 retention rate of no less than 50%, a vitamin K1 retention rate of no less than 45%, and a squalene retention rate of no less than 57%.

[0068] The present invention will be described in detail below through examples.

[0069] In the following examples, unless otherwise specified, the experimental instruments, reagents, and raw materials involved are all commercially available, and the reagents are all analytically pure products.

[0070] It should be noted that, in the following examples, 100 parts by weight represents 100 kg.

[0071] raw material

[0072] Crude fish oil: Product test content is shown in Table 1;

[0073] Complexing agent: EDTA;

[0074] Protease I: papain, purchased from Pangbo Bioengineering Co., Ltd., Nanning, Guangxi;

[0075] Protease II: bromelain, purchased from Pangbo Bioengineering Co., Ltd., Nanning, Guangxi;

[0076] Phospholipase I: phospholipase A1, purchased from Novozymes;

[0077] Phospholipase II: phospholipase C, purchased from Novozymes;

[0078] Lipase I: lipase derived from Candida antarctica, model: Novozyme 435, purchased from Novozymes;

[0079] Lipase II: lipase derived from Thermomyces lanuginosus, model: Lipozyme TL IM, purchased from Novozymes.

[0080] Example 1

[0081] This example is used to illustrate that the fish oil provided by the present invention is processed according to the following refining process:

[0082] (1) The crude fish oil is first subjected to high-speed shearing with water, a complex enzyme, and a complexing agent, and then subjected to a first mixing in a reaction tank to obtain a mixed material; the conditions for the first mixing are: temperature 37° C., time 120 min, and stirring speed 400 rpm;

[0083] Relative to 100 parts by weight of crude fish oil, the amount of water is 8 parts by weight, the amount of the complex enzyme is 0.05 parts by weight, and the amount of the complex agent is 0.001 parts by weight; the complex enzyme is a combination of protease I, phospholipase I, and lipase I in a mass ratio of 1:4:5;

[0084] (2) The mixed material was heated to 80° C. and separated in a disc centrifuge (centrifugal speed: 10,000 rpm) to obtain an oil phase material, and then the oil phase material was washed with water in the first solution (temperature: 95° C., time: 10 min) and then washed with water in the second solution (temperature: 95° C., time: 10 min) to obtain an intermediate material I;

[0085] The pH value of the first solution is 6, and the pH value of the second solution is 7.5;

[0086] Relative to 100 parts by weight of the oil phase material, the amount of the first aqueous solution is 15 parts by weight; the amount of the second aqueous solution is 15 parts by weight;

[0087] (3) The intermediate material I is first subjected to stirring adsorption with adsorption material I at a temperature of 85°C for 15 minutes and then circulated and filtered three times, then subjected to stirring adsorption with adsorption material II at a temperature of 85°C for 15 minutes and then circulated and filtered three times, and finally subjected to stirring adsorption with adsorption material III at a temperature of 85°C for 15 minutes and then circulated and filtered three times to obtain intermediate material II; the adsorption material I in the first adsorption decolorization is a combination of silica gel and water with a content mass ratio of 1:1; the adsorption material II in the second adsorption decolorization is bleaching clay; and the adsorption material III in the third adsorption decolorization is activated carbon;

[0088] And relative to 100 parts by weight of the intermediate material I, the amount of the adsorbent material I is 1 part by weight, the amount of the adsorbent material II is 1.5 parts by weight, and the amount of the adsorbent material III is 0.5 parts by weight;

[0089] (4) Deodorizing the intermediate material II in a multi-temperature-section combined deodorizing tower to obtain fish oil product S1; the deodorizing conditions are: temperature of 210° C. and time of 30 min.

[0090] Example 2

[0091] (1) The crude fish oil is first subjected to high-speed shearing with water, a complex enzyme, and a complexing agent, and then subjected to a first mixing in a reaction tank to obtain a mixed material; the conditions for the first mixing are: temperature 37° C., time 120 min, and stirring speed 400 rpm;

[0092] Relative to 100 parts by weight of crude fish oil, the amount of water is 5 parts by weight, the amount of the complex enzyme is 0.03 parts by weight, and the amount of the complex agent is 0.002 parts by weight; the complex enzyme is a combination of protease I, phospholipase I, and lipase I in a mass ratio of 1:3:4;

[0093] (2) The mixed material was heated to 80° C. and separated in a disc centrifuge (centrifugal speed: 10,000 rpm) to obtain an oil phase material, and then the oil phase material was washed with water in the first solution (temperature: 95° C., time: 10 min) and then washed with water in the second solution (temperature: 95° C., time: 10 min) to obtain an intermediate material I;

[0094] The pH value of the first solution is 5.5, and the pH value of the second solution is 7.2;

[0095] Relative to 100 parts by weight of the oil phase material, the amount of the first aqueous solution is 10 parts by weight; the amount of the second aqueous solution is 10 parts by weight;

[0096] (3) The intermediate material I is first subjected to stirring adsorption with adsorption material I at a temperature of 85°C for 10 minutes and then circulated and filtered three times, then subjected to stirring adsorption with adsorption material II at a temperature of 85°C for 15 minutes and then circulated and filtered three times, and finally subjected to stirring adsorption with adsorption material III at a temperature of 85°C for 10 minutes and then circulated and filtered three times to obtain intermediate material II; the adsorption material I in the first adsorption decolorization is a combination of silica gel and water with a content mass ratio of 1:1; the adsorption material II in the second adsorption decolorization is bleaching clay; and the adsorption material III in the third adsorption decolorization is activated carbon;

[0097] And relative to 100 parts by weight of the intermediate material I, the amount of the adsorbent material I is 2 parts by weight, the amount of the adsorbent material II is 2 parts by weight, and the amount of the adsorbent material III is 1 part by weight;

[0098] (4) Deodorizing the intermediate material II in a multi-temperature-section combined deodorizing tower to obtain a fish oil product S2; the deodorizing conditions are: temperature of 210° C. and time of 30 min.

[0099] Example 3

[0100] This example was carried out using a process similar to that of Example 1, except that, in this example, the amount of crude fish oil was controlled to be the same as that of Example 1, but, relative to 100 parts by weight of crude fish oil, the amount of water was 8 parts by weight, the amount of the complex enzyme was 0.06 parts by weight, and the amount of the complexing agent was 0.001 parts by weight.

[0101] The rest are the same as in Example 1.

[0102] The fish oil product S3 was prepared.

[0103] Example 4

[0104] This example is carried out using a process similar to that of Example 1, except that, in this example, the amount of the control complex enzyme is the same as that of Example 1, but the complex enzyme is a combination of protease I, phospholipase I and lipase I in a mass ratio of 1:2:5.

[0105] The rest are the same as in Example 1.

[0106] The fish oil product S4 was prepared.

[0107] Example 5

[0108] This example was carried out using a process similar to that of Example 1, except that in this example, an equal mass of Protease II was used to replace Protease I in Example 1.

[0109] The rest are the same as in Example 1.

[0110] The fish oil product S5 was prepared.

[0111] Example 6

[0112] This example was carried out using a process similar to that of Example 1, except that, in this example, an equal mass of phospholipase II was used to replace the phospholipase I in Example 1.

[0113] The rest are the same as in Example 1.

[0114] The fish oil product S6 was prepared.

[0115] Example 7

[0116] This example was carried out using a process similar to that of Example 1, except that, in this example, lipase I in Example 1 was replaced with lipase II of equal mass.

[0117] The rest are the same as in Example 1.

[0118] The fish oil product S7 was prepared.

[0119] Example 8

[0120] This embodiment is carried out using a process similar to that of Example 1, except that the water washing step of this embodiment is different from that of Example 1, specifically:

[0121] (1) Same as Example 1;

[0122] (2) The mixture was heated to 80° C. and separated in a disc centrifuge (centrifugal speed: 10,000 rpm) to obtain an oil phase material, and then the oil phase material was washed with water five times in a second solution (temperature: 95° C., each time for 10 minutes) to obtain an intermediate material I;

[0123] The pH value of the second solution is 7.5; the amount of the second aqueous solution is 15 parts by weight relative to 100 parts by weight of the oil phase material;

[0124] (3) Same as Example 1;

[0125] (4) The same method as in Example 1 was used to prepare fish oil product S8.

[0126] Comparative Example 1

[0127] This comparative example was prepared using the prior art refining process, and the specific process is as follows:

[0128] (1) heating crude fish oil to 75° C. and mixing it with a phosphoric acid aqueous solution to obtain a mixture; the phosphoric acid aqueous solution has a concentration of 30 wt % and contains 0.001 wt % of EDTA; the amount of the phosphoric acid aqueous solution used is 0.1 wt % of the crude fish oil based on the phosphoric acid;

[0129] (2) alkali refining the mixed material, setting the cooler outlet oil temperature to 35° C., adding 0.1 kg of 12 wt % alkali solution (sodium hydroxide) and stirring; obtaining intermediate material I;

[0130] (3) The intermediate material I is heated to 85°C in a heat exchanger and then centrifuged in a soap removal centrifuge to obtain an oil phase material;

[0131] (4) The oil phase material was washed in an aqueous solution with a pH value of 5.0 (temperature 95° C., time 15 min, the amount of aqueous solution used was 15 wt % of the oil phase material) to obtain intermediate material II;

[0132] (5) The fish oil obtained in the previous step is decolorized. The oil outlet temperature is set at 90°C. A mixture of highly active white clay and activated carbon is used as a decolorizing material for decolorization. The mixture is filtered for 90 minutes until the filtrate is clear and transparent, thereby obtaining an intermediate material III free of impurities.

[0133] (6) Deodorizing the intermediate material II in a multi-temperature-section combined deodorizing tower to obtain a fish oil product DS1; the deodorizing conditions are: temperature 230° C., time 30 min.

[0134] Comparative Example 2

[0135] This comparative example was carried out using a process similar to that of Example 1, except that the amount of the complex enzyme in this comparative example was controlled to be the same as that in Example 1, but the complex enzyme was a combination of protease I, phospholipase I and lipase I in a mass ratio of 1:1:5.

[0136] The rest are the same as in Example 1.

[0137] The fish oil product DS2 was prepared.

[0138] Comparative Example 3

[0139] This comparative example was carried out using a process similar to that of Example 1, except that in this comparative example, the total amount of the complex enzyme, the mass ratio of protease I and phospholipase I were controlled to be the same as those in Example 1, but lipase I was not used.

[0140] The rest are the same as in Example 1.

[0141] The fish oil product DS3 was prepared.

[0142] Comparative Example 4

[0143] This comparative example is carried out using a process similar to that of Example 1, except that step (3) in this comparative example is different from that in Example 1, as follows:

[0144] (1) Same as Example 1;

[0145] (2) Same as Example 1;

[0146] (3) The intermediate material I is first subjected to stirring adsorption with adsorption material III at a temperature of 85° C. for 15 minutes and then circulated and filtered three times, then subjected to stirring adsorption with adsorption material II at a temperature of 85° C. for 15 minutes and then circulated and filtered three times, and finally subjected to stirring adsorption with adsorption material I at a temperature of 85° C. for 15 minutes and then circulated and filtered three times to obtain intermediate material II; adsorption material I is a combination of silica gel and water in a mass ratio of 1:1; adsorption material II is bleaching clay; and adsorption material III is activated carbon;

[0147] And relative to 100 parts by weight of the intermediate material I, the amount of the adsorbent material I is 1 part by weight, the amount of the adsorbent material II is 1.5 parts by weight, and the amount of the adsorbent material III is 0.5 parts by weight;

[0148] (4) Same as Example 1; fish oil product DS4 was prepared.

[0149] Comparative Example 5

[0150] This comparative example is carried out using a process similar to that of Example 1, except that step (3) in this comparative example is different from that in Example 1, as follows:

[0151] (1) Same as Example 1;

[0152] (2) Same as Example 1;

[0153] (3) stirring and adsorbing the intermediate material I with the adsorption material III, and the mixed material of the adsorption material II and the adsorption material I at a temperature of 85° C. for 15 minutes, and then circulating and filtering three times to obtain the intermediate material II; the adsorption material I is a combination of silica gel and water with a mass ratio of 1:1; the adsorption material II is bleaching clay; and the adsorption material III is activated carbon;

[0154] And relative to 100 parts by weight of the intermediate material I, the amount of the adsorbent material I is 1 part by weight, the amount of the adsorbent material II is 1.5 parts by weight, and the amount of the adsorbent material III is 0.5 parts by weight;

[0155] (4) Same as Example 1; fish oil product DS5 was prepared.

[0156] Test Case

[0157] The fish oil products prepared in the above examples and comparative examples were tested;

[0158] The testing standards are:

[0159] Acid Value: GB 5009.229-2016, Peroxide Value: GB 5009.227-2023, Anisidine Value: GB / T 24304-2009, Moisture and Volatile Matter: GB 5009.236-2016, Iodine Value: GB / T 5532-2022, Phosphorus Content: GB / T 5537-2008, Protein: GB 5009.5-2016, Plasticizer: SN / T 3147-2017, Heavy Metals: GB 5009.11-2024 / GB5009.12-2023; Benzopyrene: GB 5009.27-2016; 3-MCPD and Glycidyl Esters: GB 5009.191-2024; Trans Fatty Acids: GB 5009.257-2016; Mineral oil: EN 16995-2017; Vitamin A: GB 5009.82-2016; Vitamin D3: GB 5009.296-2023; Vitamin K1: GB 5009.158-2016; Squalene: LS / T 6120-2017;

[0160] The results are shown in Table 1.

[0161] Table 1

[0162]

[0163]

[0164] Table 1 (Continued)

[0165]

[0166]

[0167] Note: “ND” in Table 1 means the amount is below the limit of quantification and not accurately quantified.

[0168] The results in Table 1 indicate that the fish oil refining process employed in the present invention can effectively remove impurities such as phospholipids and proteins from crude fish oil, while strictly controlling the formation of harmful substances such as 3-MCPD and glycidyl esters during the process. Furthermore, the fish oil adsorption decolorization and deodorization effects are improved, effectively removing harmful substances such as heavy metal ions, mineral oil, and plasticizers. Furthermore, the fish oil refining process employed in the present invention can effectively retain various beneficial concomitants, such as vitamins and squalene. The resulting fish oil is of extremely high quality and rich in nutritional value, meeting the relevant oil standards of multiple countries. Therefore, the fish oil refining method and the resulting refined fish oil described in the present invention have significant commercial value.

[0169] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for refining fish oil, characterized in that: The method includes: (1) Crude fish oil is first mixed with water, a complex enzyme, and a complexing agent to obtain a mixed material; the crude fish oil contains phosphorus, protein, pigment, vitamin A, vitamin D3, vitamin K1, squalene, and has an acid value higher than 1 mg KOH / g; relative to 100 parts by weight of the crude fish oil, the amount of water is 5-8 parts by weight, the amount of the complex enzyme is 0.03-0.05 parts by weight, and the amount of the complexing agent is 0.001-0.002 parts by weight; the complex enzyme is a combination of protease, phospholipase, and lipase in a mass ratio of 1:3-4:4-5; (2) Separating and washing the mixed material in sequence to obtain intermediate material I; (3) The intermediate material I is subjected to a first adsorption decolorization, a second adsorption decolorization, and a third adsorption decolorization in sequence to obtain an intermediate material II; the adsorption material I in the first adsorption decolorization comprises silica gel; the adsorption material II in the second adsorption decolorization is bleaching clay; and the adsorption material III in the third adsorption decolorization is activated carbon; The adsorption material I also includes water, and relative to 100 parts by weight of the intermediate material I, the amount of the silica gel is 0.1-2 parts by weight, and the amount of the water is 0.1-2 parts by weight; the temperature of the first adsorption decolorization is 85°C; In the second adsorption decolorization, the amount of the bleaching clay is 0.5-3 parts by weight relative to 100 parts by weight of the intermediate material I; the temperature of the second adsorption decolorization is 85°C; In the third adsorption decolorization, the amount of the activated carbon is 0.3-3 parts by weight relative to 100 parts by weight of the intermediate material I; the temperature of the third adsorption decolorization is 85°C; (4) Deodorizing the intermediate material II to obtain a fish oil product; the fish oil product has a phosphorus residue of not more than 5 mg / kg, a protein removal rate of not less than 60%, an acid value of not more than 1 mg KOH / g, a glycidyl ester of not more than 100 μg / kg, a 3-chloropropanol ester of not more than 200 μg / kg, a vitamin A retention rate of not less than 70%, a vitamin D3 retention rate of not less than 50%, a vitamin K1 retention rate of not less than 45%, and a squalene retention rate of not less than 57%.

2. The method according to claim 1, characterized in that The protease is selected from at least one of papain, pepsin, trypsin and bromelain.

3. The method according to claim 2, characterized in that The protease is papain.

4. The method according to claim 1 or 2, characterized in that The phospholipase is selected from at least one of phospholipase A1, phospholipase A2, and phospholipase C.

5. The method according to claim 4, characterized in that The phospholipase is phospholipase A1.

6. The method according to claim 1 or 2, characterized in that The lipase is selected from at least one of lipases derived from Candida antarctica, Fusarium oxysporum, Thermomyces lanuginosus, Rhizopus miehei, Fusarium luteum, Fusarium heterosporum, Aspergillus niger var. tubingensis, and Fusarium oxysporum.

7. The method according to claim 6, characterized in that The lipase is derived from Candida antarctica.

8. The method according to any one of claims 1 to 3, characterized in that In step (2), the method further comprises: S1, washing the separated oil phase material for the first time in a first aqueous solution to obtain a first material; the pH value of the first aqueous solution is 5.1-6.9; SII. Washing the first material for the second time in a second aqueous solution to obtain an intermediate material I; the pH value of the second aqueous solution is 7.1-7.

8.

9. The method according to claim 8, characterized in that The amount of the first aqueous solution is 5-20 parts by weight relative to 100 parts by weight of the oil phase material; And / or, the conditions of the first water washing include: temperature of 80-100° C., time of 10 min-30 min; and / or, relative to 100 parts by weight of the oil phase material, the amount of the second aqueous solution is 3-20 parts by weight; And / or, the conditions for the second water washing include: temperature of 80-100° C. and time of 10 min-30 min.

10. The method according to any one of claims 1 to 3, characterized in that In step (4), the deodorization is carried out in a deodorization tower, and the deodorization conditions include: temperature of 195-210° C. and time of 10-30 min.

11. A fish oil product prepared by the method according to any one of claims 1 to 10; wherein the fish oil product has a phosphorus residual content of no more than 5 mg / kg, a protein removal rate of no less than 60%, an acid value of no more than 1 mg KOH / g, a glycidyl ester of no more than 100 μg / kg, a 3-chloropropane ester of no more than 200 μg / kg, a vitamin A retention rate of no less than 70%, a vitamin D3 retention rate of no less than 50%, a vitamin K1 retention rate of no less than 45%, and a squalene retention rate of no less than 57%.

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