Preparation method of gelatinized euphausia superba oil microcapsule

Abstract

The invention discloses a preparation method of gelatinized euphausia superba oil microcapsules, which comprises the following steps: selecting glycerol laurate as an emulsifier, mixing and stirring the glycerol laurate and euphausia superba oil, standing to obtain oleogel, mixing the oleogel as a core material with a wall material consisting of a mixture of concentrated milk protein, whey powder and corn syrup to prepare an emulsion, and preparing the gelatinized euphausia superba oil microcapsules. And preparing the gelatinized euphausia superba oil microcapsule by adopting a spray drying method. The gelatinized microcapsule prepared by the method disclosed by the invention is relatively uniform in distribution, relatively smooth in capsule body surface and relatively complete in capsule wall, and the euphausia superba oil can be well embedded by a wall material to present a one-capsule multi-core structure. The gelated euphausia superba oil microcapsule has good compactness, can effectively mask the bad smell of the euphausia superba oil, and improves the sensory performance of the euphausia superba oil.

Description

Technical Field

[0001] The present invention relates to the field of Antarctic krill oil preparation, and particularly to a method for preparing gelled Antarctic krill oil microcapsules. Background Art

[0002] Antarctic krill oil is a new type of marine functional oil extracted from Antarctic krill, containing rich functional components such as phospholipids, omega-3 polyunsaturated fatty acids (n-3 PUFAs), astaxanthin, and vitamins. In particular, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) account for more than 15% of the total fatty acids. The n-3 PUFAs in Antarctic krill oil mainly exist in the form of phospholipids, which have higher bioavailability, stronger tissue transport ability, and better health effects compared with conventional triglyceride and ethyl ester structures. Research shows that Antarctic krill oil not only has the effects of preventing major diseases such as inflammatory diseases, cardiovascular and cerebrovascular diseases, Alzheimer's disease, and diabetes, but also can play roles in antioxidant, DNA damage repair, and cognitive ability improvement. At present, Antarctic krill oil functional products have become the main direction of the commercial development of Antarctic krill.

[0003] In the production process of Antarctic krill oil, in order to ensure that its unique nutritional functional factors such as phospholipids and astaxanthin are not lost, conventional refining steps such as degumming, deacidification, decolorization, and deodorization are usually not used. Therefore, the chemical composition of the prepared Antarctic krill oil is very complex, and the contents of pro-oxidants such as metal ions, moisture, and free fatty acids are much higher than those of ordinary oils. In addition, due to its rich polyunsaturated fatty acids, its oxidation stability is poor. Lipid oxidation not only reduces the nutritional value and health effects of Antarctic krill oil, but also causes sensory quality deterioration such as darker color, increased viscosity, and generation of bad odors. The oxidation products such as aldehydes generated have certain safety hazards, seriously affecting the nutritional quality of Antarctic krill oil. In addition, Antarctic krill oil has high viscosity and poor fluidity due to its rich phospholipids, and its solubility in both aqueous and lipid phases is poor, which limits its application to a certain extent.

[0004] By encapsulating oils and fats in nano - to micron - sized capsules through microencapsulation technology, the contact between oils and fats and the outside world can be isolated. While protecting active ingredients such as PUFAs from oxidation, it can also improve the solubility of oil products, enhance their sustained - release effect, improve their usability, and expand their application scope. Currently, spray - drying is the most commonly used oil microencapsulation technology in the food industry. It has simple operation and low cost, and is suitable for encapsulating heat - sensitive bioactive compounds such as PUFAs and astaxanthin. To prepare microcapsules of hydrophobic substances such as oils, they need to be hydrated first to form an emulsion or dispersion, and then atomized through spray - drying and the atomized droplets are dehydrated to produce microcapsules. Emulsifiers are very important in the preparation of oil emulsions. They are oriented on the oil - water interface, reducing the surface tension between the oil phase and the water phase, enabling the oil phase to be evenly dispersed in the water phase in the form of small droplets, and providing steric hindrance and electrostatic repulsion interactions to stabilize the emulsion. During the spray - drying process, the oil droplets in the emulsion are surrounded by wall - material substances, and the emulsifiers are fixed between the oil droplets and the wall - material, becoming part of the capsule shell. However, Antarctic krill oil has a high phospholipid content. Phospholipids are amphiphilic and are themselves emulsifiers. When using the spray - drying method to prepare microcapsules, they are likely to be distributed on the capsule shell, resulting in poor compactness and obvious unpleasant odors of the prepared Antarctic krill oil microcapsules, which limits their application in products such as oral liquids, candies, and solid beverages. Therefore, establishing a microencapsulation method based on spray - drying technology for Antarctic krill oil to overcome problems such as obvious unpleasant odors, improve the stability of Antarctic krill oil, and broaden its application scope is an urgent problem to be solved currently. Summary of the Invention

[0005] Aiming at the above - mentioned problems, the present invention first adds monoglyceride to Antarctic krill oil, so that the phospholipids in the krill oil interact with monoglyceride to form an Antarctic krill oil organogel with a network structure. Then, the organogel is mixed with the wall - material and homogenized to form an emulsion. Finally, the emulsion is spray - dried to obtain high - quality Antarctic krill oil microcapsules. The gelated Antarctic krill oil microcapsules prepared by the present invention have good compactness and mask the unpleasant flavor of Antarctic krill oil, are suitable for industrial production, and have broad application prospects in the food field.

[0006] Aiming at the above purpose, the present invention first provides a method for preparing gelated Antarctic krill oil microcapsules, comprising the following steps:

[0007] S1. Preparation of the core - material phase: Mix Antarctic krill oil and monoglyceride, then stir, cool, and let stand to obtain Antarctic krill oil organogel, thus preparing the core - material phase;

[0008] S2. Preparation of the wall - material phase: Add the wall - material to water and stir while adding to make it evenly mixed, thus preparing the wall - material phase;

[0009] S3. Preparation of gelled Antarctic krill oil coarse emulsion: Add the core material phase obtained in step S1 to the wall material phase obtained in step S2, and shear and homogenize to obtain a gelled Antarctic krill oil coarse emulsion;

[0010] S4. Preparation of gelled Antarctic krill oil fine emulsion: Homogenize the gelled Antarctic krill oil coarse emulsion obtained in step S3 to obtain a gelled Antarctic krill oil fine emulsion;

[0011] S5. Preparation of gelled Antarctic krill oil microcapsules: Spray-dry the gelled Antarctic krill oil fine emulsion obtained in step S4 to obtain gelled Antarctic krill oil microcapsule powder.

[0012] In one embodiment of the present invention, in step S1, the fatty acid carbon chain length of the monoglyceride is C12, and the monoglyceride is monolaurin.

[0013] In one embodiment of the present invention, the addition amount of the monoglyceride in step S1 is 0.3 - 1.5 g / kg of Antarctic krill oil.

[0014] In one embodiment of the present invention, in step S1, the temperature during stirring is 60 - 80 °C, the stirring speed is 200 - 500 rpm, and the stirring time is 30 - 40 min.

[0015] In one embodiment of the present invention, the cooling and standing in step S1 is to stand at 2 - 5 °C for 10 - 12 h.

[0016] In one embodiment of the present invention, in step S2, the wall material is a mixture of concentrated milk protein, whey powder, and corn syrup, and the mass ratio of concentrated milk protein, whey powder, and corn syrup is 1:1 - 2:1 - 3.

[0017] In one embodiment of the present invention, in step S2, the mass-to-volume ratio of the wall material to water is 1:4 - 5 (kg / L).

[0018] In one embodiment of the present invention, in step S3, the mass-to-volume ratio of the core material phase to the wall material phase is 1:8 - 9 (kg / L).

[0019] In one embodiment of the present invention, in step S3, the rotation speed during shear homogenization is 3000 - 6000 rpm, and the shear time is 3 - 5 min.

[0020] In one embodiment of the present invention, in step S4, the pressure during homogenization is 30 - 50 MPa, and homogenization is repeated 3 times.

[0021] In one embodiment of the present invention, in step S5, the inlet air temperature of the spray drying is 130 - 160 °C, the outlet air temperature is 60 - 90 °C, and the feeding rate is 700 - 900 mL / h.

[0022] The present invention also provides a gelled Antarctic krill oil microcapsule prepared by the above method.

[0023] The present invention also discloses the application of the above gelled Antarctic krill oil microcapsule in the fields of food and medicine.

[0024] Beneficial effects:

[0025] 1. The present invention selects glyceryl laurate as an emulsifier, mixes and stirs it with Antarctic krill oil, and obtains an oleogel after standing. Then, using the oleogel as the core material, it is mixed with the wall material to prepare an emulsion, and a gelled Antarctic krill oil microcapsule is prepared by spray drying. The gelled microcapsules prepared by the method of the present invention are relatively uniform in distribution, the surface of the capsule body is relatively smooth, the capsule wall is relatively complete, and the Antarctic krill oil can be well embedded by the wall material, presenting a structure of multiple nuclei in one capsule.

[0026] 2. The gelled Antarctic krill oil microcapsule prepared by the method of the present invention can effectively mask the bad smell of Antarctic krill oil and improve its sensory performance.

[0027] 3. Using a mixture of concentrated milk protein, whey powder and corn syrup as the wall material to embed the gelled Antarctic krill oil, the obtained gelled Antarctic krill oil microcapsule has good compactness, thereby improving its structural stability. Description of the drawings

[0028] Figure 1 It is a scanning electron microscope image of the Antarctic krill oil microcapsule samples prepared in Example 1 and Comparative Examples 1 and 2. Among them, A (1000 times) and B (2000 times) are the microstructural images of the microcapsules prepared in Example 1, C (1000 times) and D (2000 times) are the microstructural images of the microcapsules prepared in Comparative Example 1, and E (1000 times) and F (2000 times) are the microstructural images of the microcapsules prepared in Comparative Example 2.

[0029] Figure 2 It is the electronic nose data analysis result of the Antarctic krill oil microcapsule samples prepared in Example 1 and Comparative Examples 1 and 2. AKO - GML, AKO, and AKO - GMS respectively represent the electronic nose flavor detection radar response diagrams of the microcapsules prepared in Example 1, Comparative Example 1, and Comparative Example 2. Detailed implementation manners

[0030] Source of raw materials

[0031] Antarctic krill oil was purchased from Liaoning Fishery Group Co., Ltd. (Dalian, China) and stored in a -80°C cold storage in the dark; the concentrated milk protein was food-grade concentrated milk protein, purchased from Fonterra Group (Auckland, New Zealand); the whey powder was food-grade whey powder, purchased from Shanghai Dinghao Biotechnology Co., Ltd. (Shanghai, China); the corn syrup was food-grade corn syrup, purchased from Baolingbao Biology Co., Ltd. (Shandong, China); both monolaurin and glycerol monostearate were purchased from Beijing Aladdin Biochemical Technology Co., Ltd. (Beijing, China).

[0032] Example 1

[0033] A preparation method of gelled Antarctic krill oil microcapsules includes the following steps:

[0034] S1: Add monolaurin (the addition amount is 0.9 g / kg Antarctic krill oil) to Antarctic krill oil, keep stirring at 80°C and a stirring speed of 400 rpm for 30 min, and after cooling to room temperature, let it stand at 4°C for 12 h.

[0035] S2: Add concentrated milk protein, whey powder, and corn syrup to water in sequence while stirring to make them fully dissolved to obtain an aqueous phase. The mass ratio of the concentrated milk protein, whey powder, and corn syrup is 1:1:1, and the mass-to-volume ratio of the wall material to the aqueous solution is 1:5 (kg / L).

[0036] S3: Add the aqueous phase obtained in S2 to the oil phase obtained in S1. The mass-to-volume ratio of the oil phase to the aqueous phase is 1:9 (kg / L). First, shear and homogenize at a speed of 3000 rpm for 1 min, and then shear and homogenize at a rate of 6000 rpm for 3 min to obtain a gelled crude Antarctic krill oil emulsion.

[0037] S4: Homogenize the crude emulsion obtained in S3 at 40 MPa and repeat it 3 times to obtain a gelled fine Antarctic krill oil emulsion.

[0038] S5: Spray-dry the fine emulsion obtained in S4. The inlet air temperature is 145°C, the outlet air temperature is 75°C, and the feeding rate is 700 mL / h to obtain gelled Antarctic krill oil microcapsules, denoted as AKO-GML.

[0039] Comparative Example 1

[0040] A preparation method of Antarctic krill oil microcapsules includes the following steps:

[0041] S1: Add monolaurin (the addition amount is 0.9 g / kg Antarctic krill oil) to Antarctic krill oil and stir at 80°C and a stirring speed of 400 rpm for 5 min until the monolaurin is completely dissolved in the Antarctic krill oil.

[0042] S2: Add wall materials such as concentrated milk protein, whey powder, and corn syrup into water in sequence while stirring, to make them fully dissolved. The mass ratio of the concentrated milk protein, whey powder, and corn syrup is 1:1:1, and the mass-to-volume ratio of the wall material to the aqueous solution is 1:5 (kg / L).

[0043] S3: Add the aqueous phase obtained in S2 into the oil phase obtained in S1. The mass-to-volume ratio of the oil phase to the aqueous phase is 1:9 (kg / L). Perform shear homogenization at 3000 rpm for 1 min and then at 6000 rpm for 3 min to obtain a crude Antarctic krill oil emulsion.

[0044] S4: Homogenize the crude emulsion obtained in S3 at 40 MPa and repeat 3 times to obtain a fine Antarctic krill oil emulsion.

[0045] S5: Spray-dry the fine emulsion obtained in S4. The inlet air temperature is 145 °C, the outlet air temperature is 75 °C, and the feeding rate is 700 mL / h to obtain ungelled Antarctic krill oil microcapsules, denoted as AKO.

[0046] Comparative Example 2

[0047] A method for preparing gelled Antarctic krill oil microcapsules, comprising the following steps:

[0048] S1: Add glycerol monostearate (the addition amount is 0.9 g / kg Antarctic krill oil) to Antarctic krill oil, stir at 80 °C and a stirring speed of 400 rpm, keep stirring for 30 min, and then let it stand at 4 °C for 12 h after cooling to room temperature.

[0049] S2: Add wall materials such as concentrated milk protein, whey powder, and corn syrup into water in sequence while stirring, to make them fully dissolved. The mass ratio of the concentrated milk protein, whey powder, and corn syrup is 1:1:1, and the mass-to-volume ratio of the wall material to the aqueous solution is 1:5 (kg / L).

[0050] S3: Add the aqueous phase obtained in S2 into the oil phase obtained in S1. The mass-to-volume ratio of the oil phase to the aqueous phase is 1:9 (kg / L). Perform shear homogenization at 3000 rpm for 1 min and then at 6000 rpm for 3 min to obtain a crude Antarctic krill oil emulsion.

[0051] S4: Homogenize the crude emulsion obtained in S3 at 40 MPa and repeat 3 times to obtain a fine Antarctic krill oil emulsion.

[0052] S5: Spray-dry the fine emulsion obtained in S4. The inlet air temperature is 145 °C, the outlet air temperature is 75 °C, and the feeding rate is 700 mL / h to obtain gelled Antarctic krill oil microcapsules, denoted as AKO-GMS.

[0053] The Antarctic krill oil microcapsules prepared in Example 1 and Comparative Examples 1 and 2 were observed for their microstructure after being magnified 1000 times and 2000 times. The results are as follows Figure 1 shown. Under a magnified field of view of 1000 times, the microcapsules of the gelled Antarctic krill oil prepared with monoglyceride laurate in Example 1 were relatively evenly distributed, the surface of the capsule body was relatively smooth, the capsule wall was relatively complete, and there were certain folds. Under a magnified field of view of 2000 times, it was observed that the outer capsule wall wrapped some small capsule shell spheres, showing a structure of one capsule with multiple nuclei, indicating that the Antarctic krill oil was successfully encapsulated into the capsule shell after being gelled, emulsified, and spray-dried with monoglyceride laurate. Under a magnified field of view of 1000 times, the microcapsules of the ungelled Antarctic krill oil prepared in Comparative Example 1 were less evenly distributed, showing a certain degree of aggregation, which might be caused by adhesion due to a high oil content on the surface of the capsule body. The structure of one capsule with multiple nuclei was not observed under a magnified field of view of 2000 times. Under a magnified field of view of 1000 times, the microcapsules prepared from Antarctic krill oil gelled with glyceryl monostearate in Comparative Example 2 had a relatively smooth surface, a relatively complete capsule wall, and were evenly distributed, but the structure of one capsule with multiple nuclei was not observed under a magnified field of view of 2000 times, indicating that the addition of glyceryl monostearate was not conducive to the encapsulation of Antarctic krill oil.

[0054] The Antarctic krill oil microcapsules prepared in Example 1 and Comparative Examples 1 and 2 were detected by an electronic nose. The results are as follows Figure 2 shown. In comparison, the response values of the microcapsule samples of Antarctic krill oil gelled with monoglyceride laurate in the example were all less than those of the microcapsule samples of ungelled Antarctic krill oil on the W1C, W5S, W3C, W6S, W5C, W1S, W1W, W2S, W2W, and W3S sensors, which represented that the concentrations of volatile substances such as aromatic hydrocarbons, nitrogen oxides, ammonia, hydrides, short-chain alkanes, methyl compounds, inorganic sulfides, alcohols, aldehydes, ketones and sulfides, and long-chain alkanes in the former were lower, and the flavor quality was better. If glyceryl monostearate was used to prepare the gelled Antarctic krill oil microcapsules, the response values of the prepared microcapsule samples on the W1C, W5S, W3C, W6S, W5C, W1S, W1W, W2S, W2W, and W3S sensors were much greater than those of Example 1 and Comparative Example 1, indicating that the type of monoglyceride had a greater impact on the embedding effect of the microcapsules and the release of flavor factors. Only by using monoglyceride laurate to gel Antarctic krill oil, emulsifying the emulsion mixed with it and water phase, and spray-drying it, the prepared microcapsules could significantly improve the flavor quality.

[0055] The examples provided above are not intended to limit the scope covered by the present invention, nor are the described steps intended to limit their execution order. Obvious improvements made by those skilled in the art to the present invention in combination with the existing common general knowledge also fall within the protection scope defined by the claims of the present invention.

Claims

1. A preparation method of gelled Antarctic krill oil microcapsules, characterized in that, It includes the following steps: S1. Preparation of the core material phase: Mix Antarctic krill oil with monoglyceride, then stir, cool and let stand to obtain Antarctic krill oil oleogel, thus preparing the core material phase; S2. Preparation of the wall material phase: Add the wall material to water and stir while adding to make it evenly mixed, thus preparing the wall material phase; S3. Preparation of the gelated Antarctic krill oil coarse emulsion: Take the core material phase prepared in step S1 and add it to the wall material phase prepared in step S2, and shear and homogenize to obtain the gelated Antarctic krill oil coarse emulsion; S4. Preparation of the gelated Antarctic krill oil fine emulsion: Homogenize the gelated Antarctic krill oil coarse emulsion prepared in step S3 to obtain the gelated Antarctic krill oil fine emulsion; S5. Preparation of the gelated Antarctic krill oil microcapsules: Spray-dry the gelated Antarctic krill oil fine emulsion prepared in step S4 to obtain the gelated Antarctic krill oil microcapsule powder; Among them, in step S1, the fatty acid carbon chain length in the monoglyceride is C12, and the monoglyceride is monolaurin.

2. The preparation method according to claim 1, wherein In step S1, the addition amount of the monoglyceride is 0.3 - 1.5 g / kg of Antarctic krill oil, the temperature during stirring is 60 - 80 °C, the stirring speed is 200 - 500 rpm, and the stirring time is 30 - 40 min.

3. The preparation method according to claim 1, characterized in that, In step S1, the cooling and standing is to stand at 2 - 5 °C for 10 - 12 h.

4. The preparation method according to claim 1, wherein In step S2, the wall material is a mixture of concentrated milk protein, whey powder and corn syrup, and the mass ratio of the concentrated milk protein, whey powder and corn syrup is 1:1 - 2:1 - 3.

5. The preparation method according to claim 1, wherein, The mass-volume ratio of the wall material to water is 1 kg:4 L - 5 L.

6. The preparation method according to claim 1, characterized in that, In step S3, the mass-volume ratio of the core material phase to the wall material phase is 1 kg:8 L - 9 L, the rotation speed during shear homogenization is 3000 - 6000 rpm, and the shear time is 3 - 5 min.

7. The preparation method according to claim 1, characterized in that, In step S4, the pressure during homogenization is 30 - 50 MPa, and homogenization is repeated 3 times.

8. The preparation method according to claim 1, characterized in that In step S5, the inlet air temperature of the spray drying is 130 - 160 °C, the outlet air temperature is 60 - 90 °C, and the feeding speed is 700 - 900 mL / h.

9. The gelated Antarctic krill oil microcapsules prepared by the preparation method according to any one of claims 1 - 8.

10. The application of the gelated Antarctic krill oil microcapsules according to claim 9 in the fields of food and medicine.

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