Method for preparing polyunsaturated fatty acid calcium with low peroxide value

Abstract

The invention belongs to the fields of grease chemistry and chemical industry, and discloses a method for preparing polyunsaturated fatty acid calcium with a low peroxide value. According to the method, a polyunsaturated fatty acid raw material and an alkaline calcium compound directly react to obtain polyunsaturated fatty acid calcium salt by controlling the temperature (90-130 DEG C) and the pressure (0.12-0.20 MPa) of a reaction system under the protection effect of inert gas, and then the polyunsaturated fatty acid calcium salt is crushed, washed with water, dried and the like to prepare the low-peroxide-value polyunsaturated fatty acid calcium product. The method is simple in process, short in reaction time and low in temperature requirement, the product yield exceeds 96%, the damage rate of unsaturated fatty acid in the prepared polyunsaturated fatty acid calcium product is low, the fishy smell is light, the peroxide value is stably lower than 4.0 meq / kg, and the method is suitable for large-scale production of polyunsaturated fatty acid calcium.

Description

Technical Field

[0001] The invention belongs to the technical field of biochemical separation and discloses a method for preparing low peroxide value polyunsaturated fatty acid calcium. Background Art

[0002] In recent years, with the rise of healthy consumption trends and increased nutritional demand for pregnant women and infants, the market size of polyunsaturated fatty acid products in my country has grown rapidly. Polyunsaturated fatty acids have a variety of benefits, including supporting brain cell development, improving blood circulation, maintaining retinal function, combating allergies, and boosting immunity. They have positive effects on improving memory loss, preventing cerebral thrombosis, protecting eyesight, preventing allergic diseases, and reducing the risk of disease. However, polyunsaturated fatty acids are easily oxidized, which produces a fishy odor and affects consumer acceptance. Polyunsaturated fatty acid calcium powder can, to some extent, overcome these shortcomings. Its excellent stability and storage properties, while retaining the health benefits of algae oil and providing calcium supplementation, make it a more ideal nutritional supplement option.

[0003] Various methods for preparing polyunsaturated fatty acid calcium products are known in the prior art. For example, Chinese invention patent publication number CN1270160A discloses a method for preparing a polyunsaturated fatty acid calcium pharmaceutical product, comprising saponification followed by acidification to obtain free fatty acids, followed by reaction of the purified free fatty acids with calcium hydroxide to obtain the polyunsaturated fatty acid calcium product. US invention patent publication number US5382678A discloses a batch production process for alkaline earth metal salts of fatty acids, wherein glyceride-type fish oil polyunsaturated fatty acids are directly calcified with calcium oxide or calcium hydroxide at a high temperature of 250°C. Chinese invention patent publication number CN105566090A discloses a method for preparing polyunsaturated fatty acid calcium, involving synthesizing polyunsaturated fatty acid calcium by reacting free polyunsaturated fatty acids with a calcified substance.

[0004] However, existing methods for preparing calcium polyunsaturated fatty acids suffer from problems such as low yield, high requirements for raw materials, complicated reaction steps, or high reaction temperatures. These problems not only lead to low overall production efficiency and high energy consumption, but also easily induce side reactions such as oxidation of polyunsaturated fatty acids. The resulting calcium polyunsaturated fatty acid products have excessively high peroxide values, a strong fishy odor, and poor overall quality. Summary of the Invention

[0005] To address these shortcomings, the present invention provides a method for preparing polyunsaturated fatty acid calcium with a low peroxide value. This method is simple, has a high product yield, and produces a polyunsaturated fatty acid calcium product with a low unsaturated fatty acid destruction rate, a mild fishy odor, and a low peroxide value.

[0006] To achieve the above objectives, the present invention provides the following technical solutions: In a first aspect, the present invention provides a method for preparing low peroxide value polyunsaturated fatty acid calcium, the method comprising the following steps: S1: Put polyunsaturated fatty acid raw materials, alkaline calcification and purified water in a mass ratio of 1: (0.15-0.3): (1-1.6) into a reactor; S2: controlling the volume fraction of oxygen in the reactor to ≤2%, maintaining the temperature at 90-130° C. and the pressure at 0.12-0.20 MPa, and continuously stirring in a closed environment to allow the polyunsaturated fatty acid raw material to react with the alkaline calcification to a reaction endpoint; S3: After cooling, taking the solid product in the reactor; crushing the solid product to obtain solid product particles; S4: repeatedly washing the solid product particles described in S3 with water until the pH of the washing liquid reaches 7-8, and drying the washed solid product particles to obtain a dry material; S5: Grinding the dried material in S4 to obtain a polyunsaturated fatty acid calcium product.

[0007] The alkaline calcification in S1 includes but is not limited to calcium oxide CaO, calcium hydroxide Ca(OH)2, calcium chloride CaCl2, calcium acetate Ca(CH3COO)2, calcium lactate Ca(C6H 10 O6)2.

[0008] The low-oxygen environment (O2 volume fraction ≤ 2%) in S2 provides a stable, inert atmosphere for the reaction system, protecting the reactants and reaction products from oxidation. To achieve an O2 volume fraction ≤ 2% in the reactor, gas displacement can be used to replace the air in the reactor with a protective gas. Protective gases include, but are not limited to, inert gases, nitrogen, or carbon dioxide.

[0009] Optionally, S2 can reduce the oxygen content to below 0.8% by the following method: evacuate the reactor until the pressure inside the reactor is less than -0.3 MPa, then fill it with protective gas until the pressure is 0 MPa, and repeat this for more than 3 times.

[0010] The reaction endpoint of the present invention is the state of chemical equilibrium, i.e., when the forward reaction rate is equal to the reverse reaction rate, the reaction system reaches dynamic equilibrium, and the concentrations of the reactants and products no longer change. Under the reaction conditions of the present invention, the reaction system generally reaches this endpoint within 0.5-2 hours.

[0011] The present invention utilizes an alkaline calcification to directly react with polyunsaturated fatty acids to produce polyunsaturated fatty acid calcium. The combination of temperature and pressure allows the alkaline calcification to react directly with polyunsaturated fatty acids to produce polyunsaturated fatty acid calcium without requiring high temperatures, within a temperature range of 90-130°C. The reaction is also independent of the polyunsaturated fatty acid form (triglyceride or free form). Triglyceride-based polyunsaturated fatty acids, the most abundant and stable form, can be directly reacted to produce polyunsaturated fatty acid calcium, eliminating the need for pre-treatment of the raw materials to free them. This simplifies the process, reduces energy consumption, and improves product yield. Furthermore, a protective gas is used during the reaction to provide anti-oxidative protection, making the reactants and products less susceptible to oxidation. This method is simple, has a high product yield, and the resulting polyunsaturated fatty acid calcium product has a low unsaturated fatty acid destruction rate, a mild fishy odor, and a low peroxide value, making it suitable for large-scale production of polyunsaturated fatty acid calcium.

[0012] Currently, polyunsaturated fatty acids in polyunsaturated fatty acid raw materials are mostly present in the form of triglycerides. Therefore, the selection range of polyunsaturated fatty acid raw materials in the present invention is extremely broad, covering a variety of oil sources and polyunsaturated fatty acid extracts thereof. Specifically, the polyunsaturated fatty acid raw materials include, but are not limited to, one or more polyunsaturated fatty acid mixtures selected from fish oil, algae oil, linseed oil, docosahexaenoic acid, conjugated linoleic acid, and arachidonic acid.

[0013] Preferably, the polyunsaturated fatty acid raw material, alkaline calcification and purified water in S1 are added into the reactor in a mass ratio of 1:0.16:1.6.

[0014] Preferably, the polyunsaturated fatty acid raw material in S1 is algae oil and / or fish oil; the mass percentage of DHA in the algae oil and / or fish oil is ≥40%.

[0015] Preferably, the alkaline calcification in S1 is calcium hydroxide.

[0016] Preferably, nitrogen is used to replace the air in the reactor in S2, and the volume fraction of oxygen in the reactor is controlled to be ≤2%.

[0017] More preferably, the polyunsaturated fatty acid raw material in S1 is algae oil with a DHA mass percentage of ≥40%.

[0018] More preferably, the alkaline calcification in S1 is food grade calcium hydroxide.

[0019] Preferably, in S2, the temperature is maintained at 100-105° C. and the pressure is maintained at 0.14-0.16 MPa.

[0020] Preferably, the particle size of the solid product particles in S3 is ≤1 mm.

[0021] In step 3, the solid product is crushed to facilitate subsequent water washing. The particle size of the solid product particles is ≤1 mm, that is, it can pass through a 20-mesh sieve.

[0022] Preferably, the water washing in S4 is repeated stirring and washing with purified water at a temperature of ≤30°C; and the water content of the dried material is ≤6%.

[0023] The moisture content of the material after drying treatment involved in the present invention is ≤6%, which means that the mass of water in the dried material accounts for no more than 6% of the total mass.

[0024] More preferably, the drying treatment in S4 is to first centrifuge the washed solid product particles to remove water equivalent to at least 60% of the mass of the solid product particles, and then perform a second drying treatment; the temperature of the second drying treatment is ≤50°C.

[0025] Polyunsaturated fatty acid calcium is prone to oxidation reactions in high temperature environments and has poor stability. For example, at 62°C, the peroxide value of polyunsaturated fatty acid calcium products will increase in a short period of time. By controlling the drying temperature, the occurrence of oxidation reactions can be effectively reduced.

[0026] Currently, most polyunsaturated fatty acid calcium products are dried using a heat drying method, which has a high drying temperature and a long drying time. Furthermore, polyunsaturated fatty acid calcium is exposed to high temperatures for a long time, which can cause oxidation reactions, resulting in a strong fishy odor and darkening of the color. The drying method provided by the present invention first removes more than 60% of the water in the product by centrifugation, followed by a second low-temperature drying process, which can achieve the purpose of drying at a lower temperature. This method is highly efficient, operates under mild conditions, and causes minimal damage to the polyunsaturated fatty acid calcium in the product, thereby improving the quality of the final product.

[0027] More preferably, the second drying process is vacuum freeze drying.

[0028] In a second aspect, the present invention also provides a polyunsaturated fatty acid calcium product prepared according to the above method for preparing low peroxide value polyunsaturated fatty acid calcium.

[0029] The polyunsaturated fatty acid calcium product provided by the present invention has a low destruction rate of unsaturated fatty acids and a light fishy smell, wherein the DHA content is ≥35%, the calcium content is ≥7%, and the peroxide value is less than 4.0 meq / kg. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The test materials used in the present invention are all common commercial products and can be purchased in the market.

[0032] Example 1 This embodiment provides a method for preparing low peroxide value polyunsaturated fatty acid calcium, which consists of the following steps.

[0033] (1) Weigh 20 kg of algae oil (DHA content 40%), 3.2 kg of calcium hydroxide (food grade), and 32 kg of purified water, and put them into a high-pressure and high-temperature reactor.

[0034] (2) Evacuate the reactor until the pressure is less than -0.3 MPa, then fill it with nitrogen until the pressure reaches 0 MPa. Repeat the same process three times. Under nitrogen protection, heat the reactor to 100-105°C, control the pressure in the reactor to 0.14-0.16 MPa, and continue stirring in a closed environment for about 1 hour to reach the reaction endpoint.

[0035] (3) After the temperature in the reactor is cooled to less than or equal to 25°C, the aqueous solution is discharged and the solid product in the reactor is taken out; the solid product is crushed with a universal grinder and sieved through a 20-mesh sieve to obtain solid product particles.

[0036] (4) Wash the solid product particles with purified water at 20°C, repeatedly stirring and washing until the pH of the washing liquid reaches 7-8; centrifuge the washed solid product particles to remove at least 70% of the water content of the solid product particles, and then vacuum dry them in a vacuum drying oven (drying temperature 50°C, vacuum pressure less than -0.8 MPa) until the moisture content of the material is less than 6%, thereby obtaining a dry material.

[0037] (5) The dried material is crushed to obtain a polyunsaturated fatty acid calcium product.

[0038] The DHA content and calcium content of the polyunsaturated fatty acid calcium were detected and calculated to be 37%, 7.8%, the yield of the reactants was 96%, and the peroxide value was 2.8 meq / kg.

[0039] Example 2 This embodiment provides a method for preparing low peroxide value polyunsaturated fatty acid calcium, which consists of the following steps.

[0040] (1) Weigh 80 kg of algae oil (DHA content 40%), 12.8 kg of calcium hydroxide (food grade), and 100 kg of purified water, and place them into a high-pressure and high-temperature reactor.

[0041] (2) Evacuate the reactor until the pressure is less than -0.3 MPa, then fill it with nitrogen until the pressure reaches 0 MPa. Repeat the same process three times. Under nitrogen protection, heat the reactor to 105-110°C, control the pressure in the reactor to 0.16-0.18 MPa, and continue stirring in a closed environment for about 1 hour to reach the reaction endpoint.

[0042] (3) After the temperature in the reactor is cooled to less than or equal to 25°C, the aqueous solution is discharged and the solid product in the reactor is taken out; the solid product is crushed with a universal grinder and sieved through a 20-mesh sieve to obtain solid product particles.

[0043] (4) Wash the solid product particles with purified water at 25°C, repeatedly stirring and washing until the pH of the washing liquid reaches 7-8; centrifuge the washed solid product particles to remove at least 60% of the water content of the solid product particles, and then vacuum dry them in a vacuum drying oven (drying temperature 50°C, vacuum pressure less than -0.8 MPa) until the moisture content of the material is less than 6%, thereby obtaining a dry material.

[0044] (5) The dried material is crushed to obtain a polyunsaturated fatty acid calcium product.

[0045] The DHA content and calcium content of the polyunsaturated fatty acid calcium were detected and calculated to be 38%, 7.8%, 97% and 3.4 meq / kg, respectively.

[0046] Example 3 This embodiment provides a method for preparing low peroxide value polyunsaturated fatty acid calcium, which consists of the following steps.

[0047] (1) Weigh 5 kg of algae oil (DHA content 40%), 0.75 kg of calcium hydroxide (food grade), and 5 kg of purified water respectively, and put them into a high-pressure and high-temperature reactor.

[0048] (2) Evacuate the reactor until the pressure is less than -0.3 MPa, then fill it with nitrogen until the pressure reaches 0 MPa. Repeat the same process three times. Under nitrogen protection, heat the reactor to 90-100°C, control the pressure in the reactor to 0.12-0.14 MPa, and continue stirring in a closed environment for about 1.5 hours to reach the reaction endpoint.

[0049] (3) After the temperature in the reactor is cooled to less than or equal to 25°C, the aqueous solution is discharged and the solid product in the reactor is taken out; the solid product is crushed with a universal grinder and sieved through a 20-mesh sieve to obtain solid product particles.

[0050] (4) Wash the solid product particles with purified water at 30°C, repeatedly stirring and washing until the pH of the washing liquid reaches 7-8; centrifuge the washed solid product particles to remove at least 70% of the water mass of the solid product particles, and then use a freeze dryer to vacuum freeze-dry (freezing temperature -20°C) until the water content of the material is less than 6%, thereby obtaining a dry material.

[0051] (5) The dried material is crushed to obtain a polyunsaturated fatty acid calcium product.

[0052] The DHA content and calcium content of the polyunsaturated fatty acid calcium were detected and calculated to be 39%, 7.8%, 97% and 1.8 meq / kg, respectively.

[0053] Example 4 This embodiment provides a method for preparing low peroxide value polyunsaturated fatty acid calcium, which consists of the following steps.

[0054] (1) Weigh 5 kg of algae oil (DHA content 40%), 1.5 kg of calcium hydroxide (food grade), and 5 kg of purified water, and put them into a high-pressure and high-temperature reactor.

[0055] (2) Evacuate the reactor until the pressure is less than -0.3 MPa, then fill it with nitrogen until the pressure reaches 0 MPa. Repeat the same process three times. Under nitrogen protection, heat the reactor to a temperature of 120-130°C, control the pressure in the reactor to 0.18-0.2 MPa, and continue stirring in a closed environment for about 0.5 h to reach the reaction endpoint.

[0056] (3) After the temperature in the reactor is cooled to less than or equal to 25°C, the aqueous solution is discharged and the solid product in the reactor is taken out; the solid product is crushed with a universal grinder and sieved through a 20-mesh sieve to obtain solid product particles.

[0057] (4) Wash the solid product particles with purified water at 20°C, repeatedly stirring and washing until the pH of the washing liquid reaches 7-8; centrifuge the washed solid product particles to remove at least 60% of the water mass of the solid product particles, and then use a freeze dryer to vacuum freeze-dry (freezing temperature -20°C) until the water content of the material is less than 6%, thereby obtaining a dry material.

[0058] (5) The dried material is crushed to obtain a polyunsaturated fatty acid calcium product.

[0059] The DHA content and calcium content of the polyunsaturated fatty acid calcium were detected and calculated to be 38%, 7.8%, 96% and 1.9 meq / kg, respectively.

[0060] Comparative Example 1 This comparative example provides a method for preparing polyunsaturated fatty acid calcium, which consists of the following steps.

[0061] (1) Weigh 5 kg of algae oil (DHA content 40%), 0.8 kg of calcium hydroxide (food grade), and 8 kg of purified water, and put them into a high-pressure and high-temperature reactor.

[0062] (2) Evacuate the reactor until the pressure is less than -0.3 MPa, then fill it with nitrogen until the pressure is 0 MPa. Repeat the same process three times. Under nitrogen protection, heat the reactor to 100-105°C, control the pressure in the reactor to 0-0.1 MPa, and continue stirring in a closed environment for 2 h.

[0063] (3) After the temperature in the reactor cools to about 20°C, the aqueous solution is discharged and the remaining reactants in the reactor are collected.

[0064] The remaining reactant was in the form of a cream, which was very sticky and could not be shaped after drying. A small amount of sampling was performed to test whether some of the algae oil in the cream had not reacted, indicating a poor reaction rate.

[0065] Comparative Example 2 This comparative example provides a method for preparing polyunsaturated fatty acid calcium, which consists of the following steps.

[0066] (1) Weigh 5 kg of algae oil (DHA content 40%), 0.8 kg of calcium hydroxide (food grade), and 8 kg of purified water, and put them into a high-pressure and high-temperature reactor.

[0067] (2) Evacuate the reactor until the pressure is less than -0.3 MPa, then fill it with nitrogen until the pressure reaches 0 MPa. Repeat the same process three times. Under nitrogen protection, heat the reactor to 80-90°C, control the pressure in the reactor to 0.14-0.16 MPa, and continue stirring in a closed environment for 2 h.

[0068] (3) After the temperature in the reactor cools to about 20°C, the aqueous solution is discharged and the remaining reactants in the reactor are collected.

[0069] During the reaction process, part of the algae oil failed to react fully, resulting in the reactant failing to form a solid. The remaining reactant had a relatively thin creamy texture and could not be dried to obtain a shaped polyunsaturated fatty acid calcium product.

[0070] Comparative Example 3 This comparative example provides a method for preparing polyunsaturated fatty acid calcium, which consists of the following steps.

[0071] (1) Weigh 5 kg of algae oil (DHA content 40%), heat to 70-80℃ and set aside.

[0072] (2) Weigh 0.5 kg of sodium hydroxide and add it to 2 kg of water to dissolve it to obtain a sodium hydroxide aqueous solution.

[0073] (3) Add all the sodium hydroxide aqueous solution dropwise to the heated algae oil to carry out saponification reaction. Control the temperature during the addition reaction at 70-80°C for 1.5 h to obtain a sodium fatty acid reaction solution.

[0074] (4) Weigh 1 kg of calcium chloride and dissolve it to obtain a 0.2 kg / L calcium chloride aqueous solution. Add the calcium chloride aqueous solution dropwise to the sodium fatty acid reaction solution and stir at 50-60°C for 1.5 h. After the reaction is complete, filter and collect the solid.

[0075] (5) The collected solid is washed with purified water at a temperature below 20°C. When the pH of the washing solution is lower than 10, the obtained solid gradually softens and becomes a creamy paste, which cannot be dried to obtain the finished product.

[0076] Comparative Example 4 This comparative example provides a method for preparing low peroxide value polyunsaturated fatty acid calcium. The method is the same as comparative example 3, except that, in step (5), the collected solid is washed with purified water having a temperature below 20°C until the pH of the washing liquid is 10.5; the obtained solid is centrifuged to remove at least 60% of the mass fraction of water, and then vacuum freeze-dried using a freeze dryer (freezing temperature -20°C) to dry the material until the moisture content is less than 6%, thereby obtaining a dried material; and the dried material is pulverized to obtain a polyunsaturated fatty acid calcium product.

[0077] The detection and calculation of the DHA content in the unsaturated fatty acid calcium were 33%, the calcium content was 8.0%, the reactant yield was 85%, the peroxide value was 20.3 meq / kg, the pH was greater than 10 (a lot of alkaline substances remained), the product had a strong fishy smell and a yellowish color.

[0078] Comparative Example 5 This comparative example provides a method for preparing low-polyunsaturated fatty acid calcium. Steps (1) to (3) and (5) are the same as those in Example 1, except that in step (4), the solid product particles are washed with purified water at 20°C, and the washing is repeatedly stirred until the pH of the washing liquid reaches 7-8; the solid product particles are dried in a hot air drying oven at 60°C until the moisture content of the material is less than 6%, thereby obtaining a dry material.

[0079] The DHA content of the unsaturated fatty acid calcium was determined to be 19% and the peroxide value was 56 meq / kg. The product has a strong pungent odor and is dark yellow in color.

[0080] In summary, the preparation method provided by the present invention has low reaction temperature requirements and can directly carry out calcification reaction between polyunsaturated fatty acid raw materials and alkaline calcification at 90-130°C. This method has a simple process, short reaction time, high product yield, and improves the quality of polyunsaturated fatty acid calcium products. It is particularly suitable for the large-scale production of heat-sensitive polyunsaturated fatty acid calcium salts such as algae oil and fish oil.

[0081] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing low peroxide value polyunsaturated fatty acid calcium, characterized in that: The method comprises the following steps: S1: Put polyunsaturated fatty acid raw materials, alkaline calcification and purified water in a mass ratio of 1: (0.15-0.3): (1-1.6) into a reactor; S2: controlling the volume fraction of oxygen in the reactor to ≤2%, maintaining the temperature at 90-130° C. and the pressure at 0.12-0.20 MPa, and continuously stirring in a closed environment to allow the polyunsaturated fatty acid raw material to react with the alkaline calcification to a reaction endpoint; S3: After cooling, taking the solid product in the reactor; crushing the solid product to obtain solid product particles; S4: repeatedly washing the solid product particles in S3 with water until the pH of the washing solution reaches 7-8, and drying the washed solid product particles to obtain a dry material; S5: Grinding the dried material in S4 to obtain a polyunsaturated fatty acid calcium product.

2. The method for preparing low peroxide value polyunsaturated fatty acid calcium according to claim 1, wherein The mass ratio of the polyunsaturated fatty acid raw material, alkaline calcification and purified water in S1 is 1:0.16:1.

6.

3. The method for preparing low peroxide value polyunsaturated fatty acid calcium according to claim 1, wherein The polyunsaturated fatty acid raw material in S1 is algae oil and / or fish oil; the mass percentage of DHA in the algae oil and / or fish oil is ≥40%; and / or The alkaline calcification in S1 is calcium hydroxide; and / or In S2, nitrogen is used to replace the air in the reactor, and the volume fraction of oxygen in the reactor is controlled to be ≤2%.

4. The method for preparing low peroxide value polyunsaturated fatty acid calcium according to claim 3, wherein: The polyunsaturated fatty acid raw material in S1 is algae oil with a DHA mass percentage of ≥40%; and / or The alkaline calcification in S1 is food grade calcium hydroxide.

5. The method for preparing low peroxide value polyunsaturated fatty acid calcium according to claim 1, wherein In S2, the temperature is maintained at 100-105° C. and the pressure is maintained at 0.14-0.16 MPa.

6. The method for preparing low peroxide value polyunsaturated fatty acid calcium according to claim 1, characterized in that: The particle size of the solid product particles in S3 is ≤1 mm.

7. The method for preparing low peroxide value polyunsaturated fatty acid calcium according to claim 1, characterized in that: The water washing in S4 is performed by repeatedly stirring and washing with purified water at a temperature of ≤30°C; the water content of the dried material is ≤6%.

8. The method for preparing low peroxide value polyunsaturated fatty acid calcium according to any one of claims 1 to 7, characterized in that: The drying process in S4 is to first centrifuge the washed solid product particles to remove water equivalent to at least 60% of the mass of the solid product particles, and then perform a second drying process; The temperature of the second drying treatment is ≤50°C.

9. The method for preparing low peroxide value polyunsaturated fatty acid calcium according to claim 8, characterized in that: The second drying process is performed by vacuum freeze drying.

10. A polyunsaturated fatty acid calcium product prepared according to the method for preparing polyunsaturated fatty acid calcium with low peroxide value according to any one of claims 1 to 9.