Microcapsule powder rich in SN-2DHA algae oil and preparation method thereof

Abstract

The invention discloses microcapsule powder rich in SN-2DHA algal oil and a preparation method of the microcapsule powder rich in SN-2DHA algal oil, and belongs to the technical field of food. The microcapsule powder is prepared from, by mass, 58%-67% of wall materials, 25%-38% of core materials, 0.2%-0.5% of emulsifying agents, 2.1%-3.3% of antioxidants, 0.5%-1% of anti-caking agents, 1%-2% of acidity regulators and 1%-2% of taste regulators, and the wall materials are prepared from cow milk and carbohydrates according to the weight ratio of 1: (1-1.3). Meanwhile, the peroxide value of the algae oil microcapsule powder is also reduced.

Description

Technical Field

[0001] The present invention relates to the field of food technology, and in particular to a microcapsule powder rich in SN-2DHA algae oil and a preparation method thereof. Background Art

[0002] Docosahexaenoic acid (DHA) belongs to the ω-3 series of long-chain polyunsaturated fatty acids and is known as the "brain gold". It is not only an essential fatty acid for brain development, but also a component of the specific membrane structure of the central nervous system. It has an irreplaceable physiological function for the formation and development of brain cells. In addition, DHA also has biological activities such as preventing cardiovascular diseases, participating in immune regulation, anti-inflammation, and enhancing the development of the visual system. Therefore, in the daily diet of humans, the reasonable addition of a certain amount of DHA and other polyunsaturated fatty acids to the diet has received widespread attention and attention, and the nutritional value and commercial significance of DHA are becoming increasingly significant.

[0003] At present, DHA is mostly extracted from fish oil and algae oil. Marine fish eat DHA-rich algae, which makes the DHA in the algae accumulate in the fish through the food chain. Therefore, marine algae is the real source of DHA. Compared with fish, algae has the advantages of low price, wide distribution, large output, less fishy smell, and high purity of DHA, making it a more ideal source of DHA.

[0004] SN-2DHA algae oil refers to algae oil in which the carboxyl group in the DHA molecule is located on the second carbon atom of the glycerol backbone. Compared with ordinary DHA algae oil, SN-DHA algae oil has the following advantages: 1. Higher bioavailability. Studies have shown that DHA with a surface SN-2 structure is easier to digest and absorb. In the human body, the digestion and decomposition of triglycerides mainly occur in the small intestine, while the fatty acid at the SN-2 position is more easily hydrolyzed by pancreatic lipase, thereby improving the bioavailability of DHA; 2. Better stability and antioxidant properties. Due to its special molecular structure, SN-2DHA algae oil may have better oxidative stability, which helps to extend the shelf life of the product and reduce the risk of oxidative degradation during storage and processing; 3. Potential health benefits, such as supporting brain function, heart health and anti-inflammatory effects; 4. Wide application. Due to its superior stability and bioavailability, SN-2DHA algae oil can be widely used in various foods, nutritional supplements and medicines, especially those products with high requirements for DHA absorption efficiency. In general, due to its special molecular structure, SN-2DHA algae oil has significant advantages over ordinary DHA algae oil in terms of bioavailability, stability and potential health benefits, giving it greater application potential in the field of health products.

[0005] Microencapsulation technology is a controlled release technology that uses film-forming materials to embed solids or liquids to form a semi-enclosed or enclosed space, thereby protecting the core material from adverse environmental factors such as temperature and pH value, so as to improve the stability and shelf life of the encapsulated material and expand the application range of the encapsulated material. Microencapsulation technology is used to encapsulate unsaturated fatty acids, thereby improving the stability of oils and fats, and retaining their nutritional value and flavor to the maximum extent. At the same time, it can make oil-soluble substances evenly dispersed in water, and water-soluble substances evenly dispersed in the oil phase, so it has broad application prospects.

[0006] Existing DHA algae oil microcapsule preparation methods mainly include physical encapsulation method and chemical encapsulation method. Physical encapsulation method is to mix DHA algae oil with wall material and form microcapsules by physical means (such as spray drying, fluidized bed, etc.); chemical encapsulation method is to combine DHA algae oil with wall material by chemical reaction to form stable microcapsules. Although the existing DHA algae oil microcapsule preparation method can effectively improve the stability and bioavailability of DHA, there are still some problems: first, the existing method is usually unable to effectively control the uniform distribution of DHA in microcapsules, resulting in a low content of SN-2DHA in microcapsules, which affects the bioavailability of DHA; secondly, the existing DHA algae oil microcapsules generally have poor thermal stability and high peroxide value, which not only affects the shelf life of microcapsules, but also may have an adverse effect on human health. Therefore, developing a kind of algae oil microcapsule powder rich in SN-2DHA, with good thermal stability and low peroxide value at the same time, is an important challenge faced by current technology. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a microcapsule powder rich in SN-2DHA algae oil and a preparation method thereof, which effectively improves the thermal stability of the algae oil microcapsule powder and also reduces the peroxide value of the algae oil microcapsule powder.

[0008] The first object of the present invention is to provide a microcapsule powder rich in SN-2DHA algae oil, using the following technical solution:

[0009] A microcapsule powder rich in SN-2DHA algae oil, the microcapsule powder is composed of the following raw materials in percentage by weight: 58-67% of wall material, 25-38% of core material, 0.2-0.5% of emulsifier, 2.1-3.3% of antioxidant, 0.5-1% of anti-caking agent, 1-2% of acidity regulator, 1-2% of taste regulator, the wall material is composed of milk and carbohydrates in a weight ratio of 1: (1-1.3).

[0010] By adopting the above technical scheme, the combined use of the above components in the present application makes the microcapsule powder have good thermal stability and can maintain stable physical and chemical properties under high temperature environment. In addition, the combined use of the above raw materials in the present application makes the microcapsule powder of the present application have a low peroxide value and high freshness, which improves the shelf life of the microcapsules and also protects human health.

[0011] In the present application, when the wall material is composed of milk and carbohydrates, the stability of the microcapsule powder can be significantly improved. The reason is that carbohydrates can form a glassy structure on the surface of the capsule, prevent the entry of oxygen and moisture, and fill the gaps between milk proteins, thereby strengthening the integrity of the wall material and reducing the probability of oxidation and leakage of the core material. At the same time, it can also reduce the agglomeration of the capsule powder, thereby improving the stability of the microcapsule powder. In addition, when the ratio of milk to carbohydrates is limited to 1: (1-1.3) in the present application, the stability of the microcapsule powder is higher. As the amount of carbohydrate added increases, the glassy structure formed on the capsule surface is more complete, and the barrier effect on oxygen and moisture is better, which can further enhance the stability of the microcapsule powder. However, if the proportion of carbohydrates is too high, it may lead to a decrease in the mechanical properties of the wall material, such as reduced toughness and easy brittle fracture, making the capsule more easily damaged during processing and storage. When the proportion of carbohydrates is too low, the stability of the capsule will be reduced due to the lack of sufficient carbohydrates to strengthen and fill the capsule structure.

[0012] Preferably, the cow's milk is one or more of whey protein, isolated whey protein, and desalted whey powder, and the carbohydrates are one or two of maltodextrin and isomerized lactose.

[0013] By adopting the above technical scheme, the selection of wall materials in the present application can effectively protect SN-2DHA algae oil from oxidation and degradation, improve the stability of microcapsule powder, and the selection of the above wall materials has good emulsification and film-forming properties, which can improve the bioavailability of SN-2DHA.

[0014] Preferably, the cow's milk is modified cow's milk, and the modification method comprises the following steps: dissolving the cow's milk in a 0.05 mol / L PBS buffer solution with a pH of 7.0, so that the mass concentration of the cow's milk is 3-7%, then adding sodium tripolyphosphate, so that the concentration of sodium tripolyphosphate in the PBS buffer solution is 1-7%, and adjusting the pH to 8.0 after mixing evenly, stirring at a constant temperature of 40° C. for 2 hours, and then cooling to room temperature, dialyzing at 4° C. for 48 hours, and freeze-drying to obtain the modified cow's milk.

[0015] By adopting the above technical scheme, after the milk is treated with phosphorylation, the phosphorylated protein can be adsorbed on the surface of the droplets more quickly, and the introduction of phosphate ions into the protein enhances the intermolecular repulsion, preventing the oil phase droplets from reaggregating, thereby enabling the core material to be dispersed more evenly; and after phosphorylation, the hydrophobic groups in the milk are exposed to the outside, increasing the hydrophobicity of the milk, thereby enhancing the thermal stability of the wall material.

[0016] Preferably, the carbohydrate is a modified carbohydrate, and the modification method comprises the following steps: preparing the carbohydrate into a solution with a mass fraction of 30% with water, adjusting the pH of the system to 8.5-9.0 with an alkaline solution, adding octenyl succinic anhydride diluted with ethanol, reacting in a water bath at 60-70°C for 3-4 hours, and then adjusting the pH of the system to neutral with an acid to obtain a crude solution, washing with ethanol, filtering, drying and crushing to obtain the modified carbohydrate, wherein the octenyl succinic anhydride is 2-6% of the dry weight of the carbohydrate.

[0017] By adopting the above technical solution, the carbohydrates are modified to have hydrophilicity and lipophilicity. When combined with the core material, they can form a stable coating film on the surface of the core material, thereby effectively improving the embedding effect of the core material.

[0018] The inventors found that the use of sodium tripolyphosphate-modified milk and octenyl succinic anhydride-modified carbohydrates as wall materials not only has a better encapsulation effect than using milk and carbohydrates together, but also has better thermal stability than using only one of the materials, and further reduces the peroxide value. This may be because on the one hand, carbohydrates fill the gaps between milk proteins, thereby entangling and coating the grafted hydrophobic long chains and the gaps between the phosphorylated short chain groups. The combination of the two modified groups enhances the protective effect of the wall material, reduces the peroxide value, and at the same time enhances the hydrophobicity of the wall material surface and improves thermal stability. On the other hand, the two modifications also further enhance the binding force between milk and carbohydrates, thereby improving thermal stability and encapsulation effects.

[0019] Preferably, the core material is SN-2DHA algae oil, wherein the DHA content in the algae oil is 35-55%, and the SN-2DHA content is 42-52% of the total DHA content.

[0020] Preferably, the emulsifier is one or more of monoglycerol fatty acid ester and sucrose fatty acid ester.

[0021] Preferably, the antioxidant is one or more of vitamin E, ascorbyl palmitate and sodium ascorbate.

[0022] Preferably, the anti-caking agent is one or more of magnesium stearate, talc, silicon dioxide, and tricalcium phosphate.

[0023] Preferably, the acidity regulator is one or more of phosphoric acid, citric acid, malic acid and lactic acid, and the taste regulator is one or two of anhydrous butter and sweet orange oil.

[0024] The second aspect of the present invention is to provide a method for preparing the above-mentioned microcapsule powder rich in SN-2DHA algae oil, comprising the following steps:

[0025] S1. Preparation of aqueous phase: dissolve the wall material, emulsifier, antioxidant and acidity regulator in pure water accounting for 110-120% of the total mass of the microcapsule powder, heat the water bath to 60-70°C, and keep warm for 30-60 minutes;

[0026] S2, oil phase preparation: mix the core material, antioxidant and taste regulator, heat to 60-70°C, and keep warm for 10-20 minutes;

[0027] S3, adding the oil phase obtained in step S2 to the water phase obtained in step S1, shearing and dispersing while adding, with a shear rate of 13000-20000 r / min, shearing for 5-10 min, and simultaneously cooling to 55-65° C.;

[0028] S4, homogenizing the material obtained in step S3 with a homogenizer, the homogenization pressure is 3-5MPa for the second level and 30-45MPa for the first level, and then spray drying the homogenized material, the spray flow rate is 20mL / min, the inlet air temperature is 140-160°C, and the outlet air temperature is 60-110°C;

[0029] S5. After spray drying, pass through a 60-100 mesh vibrating sieve, then add an anti-caking agent and mix evenly to obtain microcapsule powder.

[0030] By adopting the above technical scheme, the present application limits the wall material dissolution temperature, dissolution time, core material dissolution temperature, and dissolution time, so that the wall material and the core material can be fully dissolved, and the core material can be evenly dispersed in the wall material, thereby improving the embedding effect of the wall material; the shear dispersion speed, time, homogenization pressure and other parameters are limited, so that the core material can be fully emulsified and evenly distributed in the aqueous phase carrier, thereby improving the uniformity and stability of the product, and the limitation of homogenization pressure and time helps to reduce the particle size of the material in the initial stage, improve the stability of the emulsion, and ensure that the oil phase is fully emulsified and evenly distributed, so that the distribution of SN-2DHA algae oil in the microcapsule is more uniform, The content of SN-2DHA in SN-2DHA algae oil is effectively increased, so that the content of SN-2DHA can reach up to more than 51% of the total DHA content, significantly improving the bioavailability of SN-2DHA. Moreover, after optimizing parameters such as temperature, time, and pressure, the present application makes the obtained DHA algae oil microcapsule powder have good thermal stability and low peroxide value, thereby increasing the shelf life of the microcapsules and also ensuring human health. Moreover, since the SN-2DHA algae oil microcapsule powder obtained in the present application has higher stability, it is beneficial to extend the shelf life and ensure product quality during storage and transportation.

[0031] In addition, compared with the existing DHA algae oil microcapsules, which have complex preparation steps and high production costs, the preparation method of the present application is simple and easy, suitable for large-scale industrial production, and has higher industrial application value.

[0032] In summary, the present invention has the following beneficial effects:

[0033] 1. The microcapsule powder prepared in the present application has good thermal stability and low peroxide value, so that the microcapsule powder maintains higher stability during storage and transportation, which is beneficial to prolonging the shelf life and ensuring product quality.

[0034] 2. The coordination of various parameters in the preparation method of the present application effectively makes the SN-2DHA algae oil more evenly distributed in the microcapsules, thereby making the content of SN-2DHA in the microcapsules higher. Moreover, since SN-2DHA is more efficiently digested and absorbed in the human body, the microcapsule powder of the present application has a higher bioavailability. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below with reference to the embodiments.

[0036] The raw materials used in the examples and comparative examples of the present application are all commercially available.

[0037] In the present application, the anticaking agent is one or a combination of magnesium stearate, talc, silicon dioxide, and tricalcium phosphate, and the effects that can be achieved are basically the same.

[0038] In the present application, the acidity regulator is one or a combination of phosphoric acid, citric acid, malic acid, and lactic acid, and the effects that can be achieved are basically the same.

[0039] Preparation Example 1

[0040] The preparation method of modified cow's milk comprises the following steps: dissolving cow's milk in a 0.05 mol / L PBS buffer solution with a pH value of 7.0 to make the mass concentration of the cow's milk 3%, then adding sodium tripolyphosphate to make the concentration of the sodium tripolyphosphate in the PBS buffer solution 1%, adjusting the pH value to 8.0 after uniform mixing, stirring at a constant temperature of 40 DEG C for 2 hours, then cooling to room temperature, dialyzing at 4 DEG C for 48 hours, and freeze-drying to obtain the modified cow's milk.

[0041] Preparation Example 2

[0042] The preparation method of modified cow's milk comprises the following steps: dissolving cow's milk in a 0.05 mol / L PBS buffer solution with a pH value of 7.0 to make the mass concentration of the cow's milk 5%, then adding sodium tripolyphosphate to make the concentration of the sodium tripolyphosphate in the PBS buffer solution 4%, adjusting the pH value to 8.0 after uniform mixing, stirring at a constant temperature of 40 DEG C for 2 hours, then cooling to room temperature, dialyzing at 4 DEG C for 48 hours, and freeze-drying to obtain the modified cow's milk.

[0043] Preparation Example 3

[0044] The preparation method of modified cow's milk comprises the following steps: dissolving cow's milk in a 0.05 mol / L PBS buffer solution with a pH value of 7.0 to make the mass concentration of the cow's milk 7%, then adding sodium tripolyphosphate to make the concentration of the sodium tripolyphosphate in the PBS buffer solution 7%, adjusting the pH value to 8.0 after uniform mixing, stirring at a constant temperature of 40 DEG C for 2 hours, then cooling to room temperature, dialyzing at 4 DEG C for 48 hours, and freeze-drying to obtain the modified cow's milk.

[0045] Preparation Example 4

[0046] The preparation method of modified carbohydrates comprises the following steps: preparing a solution with a mass fraction of 30% by weight of carbohydrates with water, adjusting the pH value of the system to 8.5 with an alkaline solution, adding octenyl succinic anhydride diluted with ethanol, reacting for 3 hours in a water bath at 35°C, adjusting the pH value of the system to neutral with an acid, obtaining a crude product solution, washing with ethanol, filtering, drying and crushing to obtain the modified carbohydrates, wherein the octenyl succinic anhydride accounts for 2% of the dry weight of the carbohydrates.

[0047] Preparation Example 5

[0048] The preparation method of modified carbohydrates comprises the following steps: preparing a solution with a mass fraction of 30% by weight of carbohydrates with water, adjusting the pH value of the system to 9.0 with an alkaline solution, adding octenyl succinic anhydride diluted with ethanol, reacting in a water bath at 40°C for 4 hours, adjusting the pH value of the system to neutral with an acid, obtaining a crude product solution, washing with ethanol, filtering, drying and crushing to obtain the modified carbohydrates, wherein the octenyl succinic anhydride accounts for 6% of the dry weight of the carbohydrates.

[0049] Example 1

[0050] A method for preparing microcapsule powder rich in SN-2DHA algae oil comprises the following steps:

[0051] S1, aqueous phase preparation: 67g wall material, 0.1g monoglyceride, 3g ascorbyl palmitate, and 2g acidity regulator citric acid are dissolved in 110g pure water, heated to 60°C in a water bath, and kept warm for 60min, wherein the wall material is composed of milk and carbohydrates in a weight ratio of 1:1, the milk is composed of 12g desalted whey powder, 15g whey protein powder and 6.5g isolated whey protein, and the carbohydrate is selected as isomerized lactose;

[0052] S2. Preparation of oil phase: 25 g of core material SN-2DHA algae oil (wherein the DHA content in the algae oil is 35-55%, and the SN-2DHA content is 42-52% of the total DHA content), 0.1 g of sucrose fatty acid ester, 0.3 g of ascorbyl palmitate, and 2 g of anhydrous butter as a taste regulator were mixed evenly, and the mixture was heated to 60° C. and kept warm for 20 min.

[0053] S3, adding the oil phase obtained in step S2 to the water phase obtained in step S1, shearing and dispersing while adding, with a shear rate of 13000 r / min, shearing for 10 min to form an emulsion, and simultaneously cooling to 55° C.;

[0054] S4, homogenizing the material obtained in step S3 three times with a homogenizer, the homogenization pressure is 3MPa for the second level and 30MPa for the first level, and then spray drying the homogenized material, the spray flow rate is 20mL / min, the inlet air temperature is 140°C, and the outlet air temperature is 60°C;

[0055] S5. The spray-dried powder is passed through a 60-100 mesh vibrating screen to remove oversized particles, and then 0.5 g of tricalcium phosphate, an anti-caking agent, is added and mixed evenly to obtain microcapsule powder.

[0056] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.028 mmol / kg, the surface oil content is 0.05%, the DHA content is 12.74%, the SN-2DHA content accounts for 48.58% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.035 mmol / kg, the surface oil content is 0.32%, the DHA content is 12.53%, the SN-2DHA content accounts for 47.56% of the total DHA content, and the tissue state is dry powder without impurities visible to the naked eye.

[0057] Example 2

[0058] A method for preparing microcapsule powder rich in SN-2DHA algae oil comprises the following steps:

[0059] S1, aqueous phase preparation: 63g wall material, 0.25g monoglyceride, 2.5g ascorbyl palmitate, and 1.5g acidity regulator citric acid are dissolved in 115g pure water, heated to 65°C in a water bath, and kept warm for 40min, wherein the wall material is composed of milk and carbohydrates in a weight ratio of 1:1, the milk is composed of 10g desalted whey powder, 15g whey protein powder and 6.5g isolated whey protein, and the carbohydrate is selected as isomerized lactose;

[0060] S2. Preparation of oil phase: 30 g of core material SN-2DHA algae oil (wherein the DHA content in the algae oil is 35-55%, and the SN-2DHA content is 42-52% of the total DHA content), 0.25 g of sucrose fatty acid ester, 0.1 g of ascorbyl palmitate, and 1.4 g of anhydrous butter as a taste regulator were mixed evenly, and the mixture was heated to 65° C. and kept warm for 15 min.

[0061] S3, adding the oil phase obtained in step S2 to the water phase obtained in step S1, shearing and dispersing while adding, with a shear rate of 16000 r / min, shearing for 10 min to form an emulsion, and simultaneously cooling to 60°C;

[0062] S4, homogenizing the material obtained in step S3 twice with a homogenizer, the homogenization pressure is 4MPa for the second level and 40MPa for the first level, and then spray drying the homogenized material, the spray flow rate is 20mL / min, the inlet air temperature is 150°C, and the outlet air temperature is 90°C;

[0063] S5. The spray-dried powder is passed through a 60-100 mesh vibrating screen to remove oversized particles, and then 1 g of tricalcium phosphate, an anti-caking agent, is added and mixed evenly to obtain microcapsule powder.

[0064] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.025mmol / kg, the surface oil content is 0.06%, the DHA content is 15.24%, the SN-2DHA content accounts for 50.57% of the total DHA content, and the 62°C destructive test shows that the peroxide value is 0.038mmol / kg after the 57th day, the surface oil content is 0.52%, the DHA content is 15.13%, the SN-2DHA content accounts for 50.12% of the total DHA content, and the tissue state is dry powder without impurities visible to the naked eye.

[0065] Example 3

[0066] A method for preparing microcapsule powder rich in SN-2DHA algae oil comprises the following steps:

[0067] S1, aqueous phase preparation: 58g wall material, 0.1g monoglyceride fatty acid ester, 1.99g sodium ascorbate, and 1g acidity regulator citric acid are dissolved in 120g pure water, and the temperature is raised to 70°C in a water bath, and kept warm for 30min, wherein the wall material is composed of milk and carbohydrates in a weight ratio of 1:1, the milk is composed of 10g desalted whey powder, 14g whey protein powder and 5g isolated whey protein, and the carbohydrate is selected as isomerized lactose;

[0068] S2. Preparation of oil phase: 37.2 g of core material SN-2DHA algae oil (wherein the DHA content in the algae oil is 35-55%, and the SN-2DHA content is 42-52% of the total DHA content), 0.1 g of sucrose fatty acid ester, 0.11 g of vitamin E, and 1 g of taste regulator sweet orange oil were mixed evenly, and the mixture was heated to 70° C. and kept warm for 10 min.

[0069] S3, adding the oil phase obtained in step S2 to the water phase obtained in step S1, shearing and dispersing while adding, with a shear rate of 20000 r / min, shearing for 5 minutes to form an emulsion, and simultaneously cooling to 65°C;

[0070] S4, homogenize the material obtained in step S3 twice with a homogenizer, the homogenization pressure is 5MPa for the second level and 45MPa for the first level, and then spray dry the homogenized material, the spray flow rate is 20mL / min, the inlet air temperature is 160°C, and the outlet air temperature is 110°C;

[0071] S5. The spray-dried powder is passed through a 60-100 mesh vibrating screen to remove oversized particles, and then 0.5 g of tricalcium phosphate, an anti-caking agent, is added and mixed evenly to obtain microcapsule powder.

[0072] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.017 mmol / kg, the surface oil content is 0.09%, the DHA content is 20.34%, the SN-2DHA content accounts for 51.57% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.045 mmol / kg, the surface oil content is 0.75%, the DHA content is 20.18%, and the SN-2DHA content accounts for 51.42% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0073] Example 4

[0074] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 3 in that the wall material is composed of milk and carbohydrates in a weight ratio of 1:1.3, the milk uses whey protein powder, and the carbohydrates use maltodextrin, and the rest are the same as Example 3.

[0075] After testing, the peroxide value of the microcapsule powder obtained in this embodiment was 0.009 mmol / kg, the surface oil content was 0.11%, the DHA content was 20.12%, the SN-2DHA content accounted for 51.51% of the total DHA content, and the 62°C destructive test showed that the peroxide value was 0.018 mmol / kg after the 57th day, the surface oil content was 0.68%, the DHA content was 19.94%, the SN-2DHA content accounted for 51.39% of the total DHA content, and the tissue state was dry powder without impurities visible to the naked eye.

[0076] Example 5

[0077] A method for preparing microcapsule powder rich in SN-2DHA algae oil is different from that in Example 3 in that an equal amount of glucose is used instead of isomerized lactose, and the rest is the same as in Example 3.

[0078] After testing, the peroxide value of the microcapsule powder obtained in this embodiment was 0.045 mmol / kg, the surface oil content was 0.14%, the DHA content was 19.98%, the SN-2DHA content accounted for 49.85% of the total DHA content, and the 62°C destructive test showed that the peroxide value was 0.113 mmol / kg after the 57th day, the surface oil content was 1.3%, the DHA content was 19.54%, the SN-2DHA content accounted for 48.79% of the total DHA content, and the tissue state was dry powder without impurities visible to the naked eye.

[0079] Example 6

[0080] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 3 in that maltose powder and lactose are used instead of isomerized lactose, wherein the total amount of maltose powder and lactose is the same as the content of isomerized lactose, and the weight ratio of maltose powder to lactose is 1:2, and the rest is the same as Example 3.

[0081] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.051 mmol / kg, the surface oil content is 0.13%, the DHA content is 20.11%, the SN-2DHA content accounts for 51.03% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.151 mmol / kg, the surface oil content is 1.2%, the DHA content is 19.87%, the SN-2DHA content accounts for 49.64% of the total DHA content, and the tissue state is dry powder without impurities visible to the naked eye.

[0082] Example 7

[0083] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 3 in that the milk is obtained by the method of Preparation Example 1, that is, the desalted whey powder, whey protein powder and isolated whey protein are all modified by the method of Preparation Example 1, and the rest are the same as Example 3.

[0084] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.011mmol / kg, the surface oil content is 0.02%, the DHA content is 20.34%, the SN-2DHA content accounts for 51.57% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.025mmol / kg, the surface oil content is 0.35%, the DHA content is 20.25%, and the SN-2DHA content accounts for 51.48% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0085] Example 8

[0086] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 3 in that the milk is obtained by the method of Preparation Example 2, that is, the desalted whey powder, whey protein powder and isolated whey protein are all modified by the method of Preparation Example 2, and the rest are the same as Example 3.

[0087] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.009 mmol / kg, the surface oil content is 0.01%, the DHA content is 20.39%, the SN-2DHA content accounts for 51.59% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.018 mmol / kg, the surface oil content is 0.26%, the DHA content is 20.31%, and the SN-2DHA content accounts for 51.49% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0088] Example 9

[0089] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 3 in that the milk is obtained by the method of Preparation Example 3, that is, the desalted whey powder, whey protein powder and isolated whey protein are all modified by the method of Preparation Example 3, and the rest are the same as Example 3.

[0090] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.012mmol / kg, the surface oil content is 0.04%, the DHA content is 20.33%, the SN-2DHA content accounts for 51.59% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.024mmol / kg, the surface oil content is 0.29%, the DHA content is 20.25%, and the SN-2DHA content accounts for 51.47% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0091] Example 10

[0092] A method for preparing microcapsule powder rich in SN-2DHA algae oil is different from that in Example 3 in that an equal amount of non-genetically modified soybean lecithin is used instead of sucrose fatty acid ester, and the rest is the same as in Example 3.

[0093] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.021mmol / kg, the surface oil content is 0.11%, the DHA content is 20.26%, the SN-2DHA content accounts for 51.52% of the total DHA content, and the 62°C destructive test shows that the peroxide value is 0.058mmol / kg after the 57th day, the surface oil content is 0.83%, the DHA content is 20.01%, and the SN-2DHA content accounts for 51.37% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0094] Embodiment 11

[0095] A method for preparing microcapsule powder rich in SN-2DHA algae oil is different from that of Example 3 in that the carbohydrate is obtained by the method of Preparation Example 4, and the rest is the same as that of Example 3.

[0096] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.011mmol / kg, the surface oil content is 0.08%, the DHA content is 20.36%, the SN-2DHA content accounts for 51.60% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.038mmol / kg, the surface oil content is 0.68%, the DHA content is 20.20%, the SN-2DHA content accounts for 51.46% of the total DHA content, and the tissue state is dry powder without impurities visible to the naked eye.

[0097] Example 12

[0098] A method for preparing microcapsule powder rich in SN-2DHA algae oil is different from that in Example 3 in that the carbohydrate is obtained by the method of Preparation Example 5, and the rest is the same as in Example 3.

[0099] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.012mmol / kg, the surface oil content is 0.07%, the DHA content is 20.39%, the SN-2DHA content accounts for 51.61% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.039mmol / kg, the surface oil content is 0.70%, the DHA content is 20.21%, and the SN-2DHA content accounts for 51.45% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0100] Example 13

[0101] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 3 in that the milk is obtained by the method of Preparation Example 2, that is, the desalted whey powder, whey protein powder and isolated whey protein are all modified by the method of Preparation Example 2, and the carbohydrates are obtained by the method of Preparation Example 4, and the rest are the same as Example 3.

[0102] After testing, the peroxide value of the microcapsule powder obtained in this embodiment is 0.003mmol / kg, the surface oil content is 0.001%, the DHA content is 20.41%, the SN-2DHA content accounts for 51.63% of the total DHA content, and the 62°C destructive test shows that after the 57th day, the peroxide value is 0.012mmol / kg, the surface oil content is 0.19%, the DHA content is 20.34%, the SN-2DHA content accounts for 51.56% of the total DHA content, and the tissue state is dry powder without impurities visible to the naked eye.

[0103] Comparative Example 13-1

[0104] A method for preparing microcapsule powder rich in SN-2DHA algae oil. Compared with Example 13, the wall material only uses the modified milk obtained by the method of Preparation Example 2, and an equal amount of modified milk replaces the modified carbohydrate. The peroxide value of the microcapsule powder prepared in this way is 0.018 mmol / kg, the surface oil content is 0.016%, the DHA content is 20.28%, and the SN-2DHA content accounts for 51.11% of the total DHA content. In a destructive test at 62°C, the peroxide value is 0.049 mmol / kg after the 57th day, the surface oil content is 0.53%, the DHA content is 20.11%, and the SN-2DHA content accounts for 50.78% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0105] Comparative Example 13-2

[0106] A method for preparing microcapsule powder rich in SN-2DHA algae oil. Compared with Example 13, the wall material only uses the modified carbohydrate obtained by the method of Preparation Example 4, and an equal amount of modified carbohydrate replaces the modified milk. The peroxide value of the microcapsule powder prepared in this way is 0.019 mmol / kg, the surface oil content is 0.021%, the DHA content is 20.16%, and the SN-2DHA content accounts for 51.13% of the total DHA content. In a destructive test at 62°C, the peroxide value is 0.058 mmol / kg after the 57th day, the surface oil content is 0.64%, the DHA content is 20.01%, and the SN-2DHA content accounts for 50.75% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0107] Comparative Example 1

[0108] A method for preparing a microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the core material is ordinary DHA algae oil, the DHA content is 35-55%, and the SN-2DHA content accounts for 26.12% of the total DHA content. The microcapsule powder prepared thereby is tested, and the peroxide value is 0.25 mmol / kg, the surface oil content is 0.82%, the DHA content is 9.18%, and the SN-2DHA content accounts for 25.86% of the total DHA content. In a destructive test at 62°C, the peroxide value is 10.26 mmol / kg after the 57th day, the surface oil content is 1.97%, the DHA content is 8.72%, and the SN-2DHA content accounts for 19.47% of the total DHA content. The tissue state is a dry powder without impurities visible to the naked eye.

[0109] Comparative Example 2

[0110] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the total amount of wall material in step S1 is 67g, consisting of 33.5g octenyl succinate starch and 33.5g gum arabic. The microcapsule powder prepared in this way is tested to have a peroxide value of 0.12mmol / kg, a surface oil content of 1.67%, a DHA content of 10.18%, and an SN-2DHA content of 42.11% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 7.9mmol / kg, the surface oil content is 1.08%, the DHA content is 9.86%, the SN-2DHA content accounts for 41.17% of the total DHA content, and the tissue state is agglomeration.

[0111] Comparative Example 3

[0112] A method for preparing a microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the total amount of wall material in step S1 is 67g, consisting of 33.5g whey protein powder and 33.5g gum arabic. The microcapsule powder prepared in this way is tested to have a peroxide value of 0.15mmol / kg, a surface oil content of 0.69%, a DHA content of 10.52%, and an SN-2DHA content of 46.17% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 12.1mmol / kg, the surface oil content is 1.59%, the DHA content is 9.87%, the SN-2DHA content accounts for 40.85% of the total DHA content, and the tissue state is agglomeration.

[0113] Comparative Example 4

[0114] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the total amount of wall material in step S1 is 67g, consisting of 33.5g isomerized lactose and 33.5g gum arabic. The microcapsule powder prepared in this way is tested to have a peroxide value of 0.19mmol / kg, a surface oil content of 0.98%, a DHA content of 8.46%, and an SN-2DHA content of 42.14% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 14.6mmol / kg, the surface oil content is 1.62%, the DHA content is 7.89%, the SN-2DHA content accounts for 39.36% of the total DHA content, and the tissue state is agglomeration.

[0115] Comparative Example 5

[0116] A method for preparing a microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the total amount of wall material in step S1 is 67g, consisting of 37.5g whey protein powder and 33.5g desalted whey powder. The microcapsule powder prepared in this way is tested to have a peroxide value of 0.12mmol / kg, a surface oil content of 0.76%, a DHA content of 11.54%, and an SN-2DHA content of 43.44% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 4.56mmol / kg, the surface oil content is 1.34%, the DHA content is 10.92%, the SN-2DHA content accounts for 42.54% of the total DHA content, and the tissue state is agglomeration.

[0117] Comparative Example 6

[0118] A method for preparing a microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the total amount of wall material in step S1 is 67g, consisting of 37.5g isomerized lactose and 33.5g maltose powder. The microcapsule powder prepared in this way is tested to have a peroxide value of 0.18mmol / kg, a surface oil content of 1.11%, a DHA content of 10.36%, and an SN-2DHA content of 42.51% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 6.21mmol / kg, the surface oil content is 2.36%, the DHA content is 9.85%, the SN-2DHA content accounts for 40.32% of the total DHA content, and the tissue state is agglomeration.

[0119] Comparative Example 7

[0120] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the total amount of wall material in step S1 is 67g, which is composed of cow's milk and isomerized lactose in a ratio of 1:1.5, specifically 22.3g cow's milk and 44.7g isomerized lactose, wherein the cow's milk is composed of 8g desalted whey powder, 11g whey protein powder, and 3.3g isolated whey protein. The microcapsule powder prepared in this way is tested, and the peroxide value is 0.13mmol / kg, the surface oil content is 0.97%, the DHA content is 11.75%, and the SN-2DHA content accounts for 45.32% of the total DHA content. In a destructive test at 62°C, the peroxide value is 3.24mmol / kg after the 57th day, the surface oil content is 2.02%, the DHA content is 11.12%, the SN-2DHA content accounts for 43.54% of the total DHA content, and the tissue state is agglomeration.

[0121] Comparative Example 8

[0122] A method for preparing a microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the total amount of wall material in step S1 is 67g, which is composed of cow's milk and isomerized lactose in a ratio of 1.5:1, specifically 40.2g cow's milk and 26.8g isomerized lactose, wherein the cow's milk is composed of 15g desalted whey powder, 20g whey protein powder, and 5.2g isolated whey protein. The microcapsule powder prepared in this way is tested, and the peroxide value is 0.21mmol / kg, the surface oil content is 1.13%, the DHA content is 10.61%, and the SN-2DHA content accounts for 43.25% of the total DHA content. In a destructive test at 62°C, the peroxide value is 4.32mmol / kg after the 57th day, the surface oil content is 2.54%, the DHA content is 10.12%, the SN-2DHA content accounts for 41.22% of the total DHA content, and the tissue state is agglomeration.

[0123] Comparative Example 9

[0124] A method for preparing a microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the shear rate in step S3 is 11000r / min, the shear time is 15min, and the rest is the same as Example 1. The microcapsule powder thus prepared has a peroxide value of 0.032mmol / kg, a surface oil content of 0.08%, a DHA content of 12.12%, and an SN-2DHA content of 46.32% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 0.042mmol / kg, the surface oil content is 0.41%, the DHA content is 11.89%, and the SN-2DHA content accounts for 45.31% of the total DHA content. The tissue state is a dry powder without impurities visible to the naked eye.

[0125] Comparative Example 10

[0126] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the shear rate in step S3 is 25000r / min, the shear time is 5min, and the rest is the same as Example 1. The microcapsule powder prepared thereby has a peroxide value of 0.035mmol / kg, a surface oil content of 0.09%, a DHA content of 12.02%, and an SN-2DHA content of 46.11% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 0.055mmol / kg, the surface oil content is 0.41%, the DHA content is 11.85%, and the SN-2DHA content accounts for 44.326% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0127] Comparative Example 11

[0128] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the second-stage homogenization pressure in step S4 is 6MPa and the first-stage homogenization pressure is 50MPa, and the rest is the same as Example 1. The microcapsule powder prepared thereby has a peroxide value of 0.033mmol / kg, a surface oil content of 0.09%, a DHA content of 12.12%, and an SN-2DHA content of 46.32% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 0.052mmol / kg, the surface oil content is 0.39%, the DHA content is 11.87%, and the SN-2DHA content accounts for 44.98% of the total DHA content. The tissue state is dry powder without impurities visible to the naked eye.

[0129] Comparative Example 12

[0130] A method for preparing microcapsule powder rich in SN-2DHA algae oil, which is different from Example 1 in that the second-stage homogenization pressure in step S4 is 2MPa and the first-stage homogenization pressure is 25MPa, and the rest is the same as Example 1. The microcapsule powder prepared thereby has a peroxide value of 0.033mmol / kg, a surface oil content of 0.09%, a DHA content of 12.23%, and an SN-2DHA content of 45.32% of the total DHA content. In a destructive test at 62°C, the peroxide value after the 57th day is 0.042mmol / kg, the surface oil content is 0.45%, the DHA content is 11.96%, and the SN-2DHA content accounts for 44.23% of the total DHA content. The tissue state is a dry powder without impurities visible to the naked eye.

[0131] From the test results of Examples 1-4 of the present application, it can be seen that the peroxide values ​​of the microcapsule powders obtained in the examples of the present application are all lower than 0.03%, and the surface oil content is all lower than 0.15%. After the destruction test at 62°C, the peroxide values ​​on the 57th day are all lower than 0.05%, and the surface oil content is all lower than 0.8%, indicating that the microcapsule powders obtained in the present application have good stability and heat resistance.

[0132] Compared with Example 3, when the carbohydrates selected are glucose or maltose powder and lactose, the peroxide value and surface oil content of the microcapsule powder obtained in Examples 6-7 are both increased compared with those in Example 3. It can be seen that after the carbohydrates are selected as isomerized lactose or maltodextrin, their combination with milk can effectively improve the stability of the microcapsule powder.

[0133] Compared with Example 3, when the cow's milk used was the modified cow's milk obtained in the preparation example, the peroxide value, surface oil content of the microcapsule powder obtained in Examples 6-8 and the peroxide value and surface oil content after the destruction test at 62°C were much smaller than those in Example 3. This shows that the stability of the microcapsule powder can be effectively improved after the cow's milk is modified with sodium tripolyphosphate.

[0134] Compared with Example 3, when an equal amount of non-genetically modified soybean lecithin is used to replace sucrose fatty acid ester, the peroxide value and surface oil content of the microcapsule powder obtained in Example 10 are increased compared with those in Example 3. At the same time, after the destructive test, the peroxide value and surface oil content of the microcapsule powder are also increased compared with those in Example 3. It can be seen that when sucrose fatty acid ester is used as the emulsifier in the present application, it is more helpful to improve the stability of the microcapsule powder.

[0135] Compared with Example 3, after the carbohydrates are modified, the peroxide value, surface oil content of the microcapsule powders obtained in Examples 10-11 and after the destruction test at 62°C are all lower than the peroxide value and surface oil content in Example 3, indicating that the carbohydrates can be improved after being modified to improve the embedding effect on the core material.

[0136] Compared with Example 3, when both carbohydrates and cow's milk are modified, the peroxide value, surface oil content and surface oil content of the microcapsule powder obtained in Example 12 after the destruction test at 62°C are much smaller than those in Example 3, indicating that after both cow's milk and carbohydrates are modified, the embedding effect of the core material can be effectively improved.

[0137] Compared with Example 1, when ordinary DHA algae oil is used, the peroxide value and surface oil content of the microcapsule powder obtained in Comparative Example 1 are much higher than those in Example 1, indicating that the stability of the microcapsules obtained in Comparative Example 1 is poor. The reason is that ordinary DHA algae oil is easily oxidized and degraded, and has a high peroxide value. In the present application, SN-2DHA algae oil is selected. Due to the high content of SN-2DHA, SN-2DHA itself is slowly oxidized and degraded, and has higher stability, which makes it more difficult for oil to precipitate from the microcapsules during the preparation process, so that the surface oil content of the microcapsule powder finally obtained is low and the peroxide value is low.

[0138] Compared with Example 1, in Comparative Examples 2-4, after the wall material consists of octenyl succinate starch and gum arabic, or consists of whey protein powder and gum arabic, or consists of isomerized lactose and gum arabic, the peroxide value and surface oil content of the microcapsule powder obtained in Comparative Examples 2-4 are significantly increased compared with the peroxide value and surface oil content in Example 1, and after a destructive test at 62°C, the peroxide value and surface oil content of the microcapsule powder at 57 days are greatly improved. It can be seen that when milk and carbohydrates are mixed as wall materials in the present application, the stability and heat resistance of the microcapsule powder can be effectively improved.

[0139] Compared with Example 1, when only milk or carbohydrates are used as the wall material, the stability of the microcapsule powder obtained in Comparative Example 5-6 is worse than that in Example 1, and after the destructive test at 62°C, the peroxide value and surface oil content of the microcapsule powder obtained in Comparative Example 5-6 are significantly increased compared with those in Example 1, indicating that the thermal stability of the microcapsule powder obtained in Comparative Example 5-6 is also poor.

[0140] Compared with Example 1, when the proportion of carbohydrates exceeds the limit of the present application or the amount of milk added exceeds the limit of the present application, the stability and thermal stability of the microcapsules obtained in Comparative Examples 7-8 are reduced compared with those in Example 1. It can be seen that excessive carbohydrates or excessive milk will lead to a decrease in the stability and heat resistance of the microcapsule powder.

[0141] Compared with Example 1, when the shear rate or homogenization pressure is lower than or exceeds the limit of the present application, the stability and thermal stability of the microcapsule powder are affected to a certain extent in Comparative Examples 9-12. It can be seen that the addition amount of the components and the coordination of the process parameters in the present application effectively improve the stability and heat resistance of the microcapsule powder.

[0142] The embodiments of this specific implementation method are all preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Therefore, all equivalent changes made according to the structure, shape, and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A microcapsule powder rich in SN-2DHA algae oil, characterized in that: The microcapsule powder is composed of the following raw materials in percentage by weight: 58-67% wall material, 25-38% core material, 0.2-0.5% emulsifier, 2.1-3.3% antioxidant, 0.5-1% anti-caking agent, 1-2% acidity regulator, and 1-2% taste regulator. The wall material is composed of milk and carbohydrates in a weight ratio of 1:(1-1.3).

2. The microcapsule powder rich in SN-2DHA algae oil according to claim 1, characterized in that: The cow's milk is one or more of whey protein, isolated whey protein, and desalted whey powder, and the carbohydrates are one or two of maltodextrin and isomerized lactose.

3. The microcapsule powder rich in SN-2DHA algae oil according to claim 1, characterized in that: The cow's milk is modified cow's milk, and the modification method comprises the following steps: dissolving the cow's milk in a 0.05 mol / L PBS buffer solution with a pH of 7.0 to make the mass concentration of the cow's milk 3-7%, then adding sodium tripolyphosphate to make the concentration of the sodium tripolyphosphate in the PBS buffer solution 1-7%, mixing evenly, adjusting the pH to 8.0, stirring at a constant temperature of 40°C for 2h, then cooling to room temperature, dialyzing at 4°C for 48h, and freeze-drying to obtain the modified cow's milk.

4. The microcapsule powder rich in SN-2DHA algae oil according to claim 1, characterized in that: The carbohydrate is a modified carbohydrate, and the modification method comprises the following steps: preparing the carbohydrate into a solution with a mass fraction of 30% with water, adjusting the pH value of the system to 8.5-9.0 with an alkaline solution, adding octenyl succinic anhydride diluted with ethanol, reacting in a water bath of 60-70°C for 3-4 hours, and then adjusting the pH value of the system to neutral with acid to obtain a crude product solution, washing with ethanol, filtering, drying and crushing to obtain the modified carbohydrate, wherein the octenyl succinic anhydride accounts for 2-6% of the dry weight of the carbohydrate.

5. The microcapsule powder rich in SN-2DHA algae oil according to claim 1, characterized in that: The core material is SN-2DHA algae oil, wherein the DHA content in the algae oil is 35-55%, and the SN-2DHA content is 42-52% of the total DHA content.

6. The microcapsule powder rich in SN-2DHA algae oil according to claim 1, characterized in that: The emulsifier is one or two of monoglycerol fatty acid ester and sucrose fatty acid ester.

7. The microcapsule powder rich in SN-2DHA algae oil according to claim 1, characterized in that: The antioxidant is one or more of vitamin E, ascorbyl palmitate and sodium ascorbate.

8. The microcapsule powder rich in SN-2DHA algae oil according to claim 1, characterized in that: The anticaking agent is one or more of magnesium stearate, talc, silicon dioxide and tricalcium phosphate.

9. The microcapsule powder rich in SN-2DHA algae oil according to claim 1, characterized in that: The acidity regulator is one or more of phosphoric acid, citric acid, malic acid and lactic acid, and the taste regulator is one or two of anhydrous butter and sweet orange oil.

10. A method for preparing a microcapsule powder rich in SN-2DHA algae oil according to any one of claims 1 to 9, characterized in that: The steps include: S1. Preparation of aqueous phase: dissolve the wall material, emulsifier, antioxidant and acidity regulator in pure water accounting for 110-120% of the total mass of the microcapsule powder, heat the water bath to 60-70°C, and keep warm for 30-60 minutes; S2, oil phase preparation: mix the core material, antioxidant and taste regulator, heat to 60-70°C, and keep warm for 10-20 minutes; S3, adding the oil phase obtained in step S2 to the water phase obtained in step S1, shearing and dispersing while adding, with a shear rate of 13000-20000 r / min, shearing for 5-10 min, and simultaneously cooling to 55-65° C.; S4, homogenizing the material obtained in step S3 with a homogenizer, the homogenization pressure is 3-5MPa for the second level and 30-45MPa for the first level, and then spray drying the homogenized material, the spray flow rate is 20mL / min, the inlet air temperature is 140-160°C, and the outlet air temperature is 60-110°C; S5. After spray drying, pass through a 60-100 mesh vibrating sieve, then add an anti-caking agent and mix evenly to obtain microcapsule powder.