A method for preparing a gelled euphausia superba oil microcapsule

Abstract

The application discloses a preparation method of gelled Euphausia superba oil microcapsules, wherein glyceryl laurate is selected as an emulsifier, mixed with Euphausia superba oil and stirred, and oil gel is obtained after standing; the oil gel is used as a core material, mixed with wall material composed of a mixture of concentrated milk protein, whey powder and corn syrup to prepare an emulsion, and the gelled Euphausia superba oil microcapsules are prepared by using a spray drying method. The gelled microcapsules prepared by the method have uniform distribution, a smooth capsule surface, a complete capsule wall, and Euphausia superba oil can be well embedded in the wall material, and a one-capsule-multiple-core structure is presented. The gelled Euphausia superba oil microcapsules have good compactness, can effectively mask the bad smell of Euphausia superba oil, and improve the sensory performance.

Description

Technical Field

[0001] This invention relates to the field of Antarctic krill oil preparation, specifically to a method for preparing gelled Antarctic krill oil microcapsules. Background Technology

[0002] Antarctic krill oil is a novel marine functional oil extracted from Antarctic krill. It is rich in phospholipids, omega-3 polyunsaturated fatty acids (n-3 PUFAs), astaxanthin, vitamins, and other beneficial components. 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 delivery capacity, and better health benefits compared to the conventional glyceride and ethyl ester structures. Studies have shown that Antarctic krill oil can prevent inflammatory diseases, cardiovascular diseases, Alzheimer's disease, diabetes, and other major diseases. It also has antioxidant effects, repairs DNA damage, and improves cognitive function. Currently, functional products made from Antarctic krill oil have become a major direction for the commercial development of Antarctic krill.

[0003] In the production of Antarctic krill oil, to ensure the preservation of its unique nutritional components such as phospholipids and astaxanthin, conventional refining steps such as degumming, deacidification, decolorization, and deodorization are typically avoided. Therefore, the resulting Antarctic krill oil has a very complex chemical composition, with significantly higher levels of pro-oxidants such as metal ions, water, and free fatty acids compared to ordinary oils. Furthermore, its high content of polyunsaturated fatty acids contributes to its poor oxidative stability. Lipid oxidation not only reduces the nutritional value and health benefits of Antarctic krill oil but also causes sensory deterioration, including darkening of color, increased viscosity, and the development of unpleasant odors. The resulting oxidation products, such as aldehydes, pose certain safety risks and severely impact the nutritional quality of Antarctic krill oil. In addition, the high phospholipid content of Antarctic krill oil leads to high viscosity and poor flowability, and its poor solubility in both aqueous and lipid-based systems limits its applications.

[0004] Microencapsulation technology encapsulates oils in nano- to micron-sized capsules, isolating them from external contact. This protects active ingredients like PUFAs from oxidation, improves solubility, enhances sustained-release effects, increases ease of use, and expands application range. Currently, spray drying is the most commonly used oil microencapsulation technology in the food industry. It is simple to operate, low-cost, and suitable for encapsulating heat-sensitive bioactive compounds such as PUFAs and astaxanthin. To prepare microcapsules of hydrophobic substances like oils, they must first be hydrated to form an emulsion or dispersion. Then, spray drying atomizes the emulsion and dehydrates the droplets to create microcapsules. Emulsifiers are crucial in oil emulsion preparation. They are oriented at the oil-water interface, reducing surface tension between the oil and water phases, allowing the oil phase to be uniformly dispersed in the water phase as small droplets, and providing steric hindrance and electrostatic repulsion to stabilize the emulsion. During spray drying, the oil droplets in the emulsion are surrounded by the wall material, while the emulsifier is fixed between the droplets and the wall material, becoming part of the capsule shell. However, Antarctic krill oil has a high phospholipid content. Phospholipids are amphiphilic and act as emulsifiers themselves. When preparing microcapsules using spray drying, they tend to distribute on the capsule shell, resulting in microcapsules with poor density and a noticeable unpleasant odor. This limits their application in oral liquids, candies, and solid beverages. Therefore, developing a spray-drying-based microencapsulation method for Antarctic krill oil to overcome its unpleasant odor and improve its stability, thereby broadening its application range, is a pressing issue. Summary of the Invention

[0005] To address the aforementioned problems, this invention first adds monoglycerides to Antarctic krill oil, allowing the phospholipids in the krill oil to interact with the monoglycerides to form an Antarctic krill oil oil oil gel with a network structure. Then, the oil gel is mixed with a wall material and homogenized to form an emulsion. Finally, the emulsion is spray-dried to obtain high-quality Antarctic krill oil microcapsules. The gelled Antarctic krill oil microcapsules prepared by this invention exhibit good density and mask undesirable flavors of Antarctic krill oil, making them suitable for industrial production and showing broad application prospects in the food industry.

[0006] To achieve the above objectives, the present invention first provides a method for preparing gelled Antarctic krill oil microcapsules, comprising the following steps:

[0007] S1. Preparation of core phase: Antarctic krill oil and monoglyceride are mixed, stirred, cooled and allowed to stand to obtain Antarctic krill oil oil gel, which is the core phase.

[0008] S2. Preparation of wall material phase: Add the wall material to water while stirring to mix it evenly and obtain the wall material phase;

[0009] S3. Preparation of gelled Antarctic krill oil crude emulsion: The core material phase obtained in step S1 is added to the wall material phase obtained in step S2, and the mixture is sheared and homogenized to obtain gelled Antarctic krill oil crude emulsion.

[0010] S4. Preparation of gelled Antarctic krill oil fine emulsion: The gelled Antarctic krill oil crude emulsion obtained in step S3 is homogenized to obtain gelled Antarctic krill oil fine emulsion.

[0011] S5. Preparation of gelled Antarctic krill oil microcapsules: The gelled Antarctic krill oil emulsion obtained in step S4 is spray-dried to obtain gelled Antarctic krill oil microcapsule powder.

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

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

[0014] In one embodiment of the present invention, the temperature during stirring in step S1 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 settling in step S1 is to settling at 2-5°C for 10-12 hours.

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

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

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

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

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

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

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

[0023] This invention also discloses the application of the above-mentioned gelled Antarctic krill oil microcapsules in the food and pharmaceutical fields.

[0024] Beneficial effects:

[0025] 1. In this invention, glyceryl laurate is selected as an emulsifier and mixed with Antarctic krill oil. After standing, an oil gel is obtained. The oil gel is then used as the core material and mixed with the wall material to prepare an emulsion. The gelled Antarctic krill oil microcapsules are prepared by spray drying. The gelled microcapsules prepared by the method of this invention are more uniformly distributed, have a smoother surface, and have a more intact wall. The Antarctic krill oil can be well embedded in the wall material, presenting a multi-core structure.

[0026] 2. The gelled Antarctic krill oil microcapsules prepared by the method of the present invention can effectively mask the unpleasant odor of Antarctic krill oil and improve its sensory properties.

[0027] 3. A mixture of concentrated milk protein, whey powder, and corn syrup was used as the wall material to encapsulate gelled Antarctic krill oil. The resulting gelled Antarctic krill oil microcapsules exhibited excellent density, thereby improving their structural stability. Attached Figure Description

[0028] Figure 1 The images shown are scanning electron microscope (SEM) images of Antarctic krill oil microcapsule samples prepared in Example 1 and Comparative Examples 1 and 2. In the images, A (1000x) and B (2000x) show the microstructure of the microcapsules prepared in Example 1, C (1000x) and D (2000x) show the microstructure of the microcapsules prepared in Comparative Example 1, and E (1000x) and F (2000x) show the microstructure of the microcapsules prepared in Comparative Example 2.

[0029] Figure 2 The following are the electronic nose data analysis results of the Antarctic krill oil microcapsule samples prepared in Example 1 and Comparative Examples 1 and 2. AKO-GML, AKO, and AKO-GMS represent the electronic nose flavor detection radar response maps of the microcapsules prepared in Example 1, Comparative Example 1, and Comparative Example 2, respectively. Detailed Implementation

[0030] Source of raw materials

[0031] Antarctic krill oil was purchased from Liaoning Fisheries Group Co., Ltd. (Dalian, China) and stored in a -80℃ cold storage facility protected from light; concentrated milk protein was food-grade concentrated milk protein, purchased from Fonterra Group (Auckland, New Zealand); whey powder was food-grade whey powder, purchased from Shanghai Dinghao Biotechnology Co., Ltd. (Shanghai, China); corn syrup was food-grade corn syrup, purchased from Baolingbao Biotechnology Co., Ltd. (Shandong, China); glyceryl monolaurate and glyceryl monostearate were both purchased from Beijing Aladdin Biochemical Technology Co., Ltd. (Beijing, China).

[0032] Example 1

[0033] A method for preparing gelled Antarctic krill oil microcapsules includes the following steps:

[0034] S1: Add glyceryl monolaurate (0.9 g / kg Antarctic krill oil) to Antarctic krill oil, stir for 30 min at 80℃ and 400 rpm, cool to room temperature and let stand at 4℃ for 12 h.

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

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

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

[0038] S5: The fine emulsion obtained in S4 was spray-dried at an inlet air temperature of 145℃, an outlet air temperature of 75℃, and a feed rate of 700mL / h to obtain gelled Antarctic krill oil microcapsules, denoted as AKO-GML.

[0039] Comparative Example 1

[0040] A method for preparing Antarctic krill oil microcapsules includes the following steps:

[0041] S1: Add glyceryl monolaurate (0.9 g / kg Antarctic krill oil) to Antarctic krill oil and stir for 5 minutes at 80°C and 400 rpm until the glyceryl monolaurate is completely dissolved in the Antarctic krill oil.

[0042] S2: Add concentrated milk protein, whey powder, corn syrup, and other wall materials sequentially to water while stirring to ensure complete dissolution. The mass ratio of concentrated milk protein, whey powder, and corn syrup is 1:1:1, and the mass-to-volume ratio of wall materials to aqueous solution is 1:5 (kg / L).

[0043] S3: Add the aqueous phase obtained from S2 to the oil phase obtained from S1, with a mass-to-volume ratio of oil phase to aqueous phase of 1:9 (kg / L). Shear homogenize at 3000 rpm for 1 min and then shear homogenize at 6000 rpm for 3 min to obtain Antarctic krill oil crude emulsion.

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

[0045] S5: The fine emulsion obtained in S4 was spray-dried at an inlet air temperature of 145°C, an outlet air temperature of 75°C, and a feed rate of 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 includes the following steps:

[0048] S1: Add glyceryl monostearate (0.9 g / kg Antarctic krill oil) to Antarctic krill oil, stir at 80°C and 400 rpm for 30 min, cool to room temperature and let stand at 4°C for 12 h.

[0049] S2: Add concentrated milk protein, whey powder, corn syrup, and other wall materials sequentially to water while stirring to ensure complete dissolution. The mass ratio of concentrated milk protein, whey powder, and corn syrup is 1:1:1, and the mass-to-volume ratio of wall materials to aqueous solution is 1:5 (kg / L).

[0050] S3: Add the aqueous phase obtained from S2 to the oil phase obtained from S1, with a mass-to-volume ratio of oil phase to aqueous phase of 1:9 (kg / L). Shear homogenize at 3000 rpm for 1 min and then shear homogenize at 6000 rpm for 3 min to obtain Antarctic krill oil crude emulsion.

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

[0052] S5: The fine emulsion obtained in S4 was spray-dried at an inlet air temperature of 145°C, an outlet air temperature of 75°C, and a feed rate of 700 mL / h to obtain gelled Antarctic krill oil microcapsules, denoted as AKO-GMS.

[0053] The microstructure of the Antarctic krill oil microcapsules prepared in Example 1 and Comparative Examples 1 and 2 was observed after magnification of 1000x and 2000x. The results are as follows: Figure 1 As shown. Under 1000x magnification, the microcapsules of gelled Antarctic krill oil prepared using glyceryl laurate in Example 1 were relatively uniformly distributed, with smooth capsule surfaces, relatively intact capsule walls, and some wrinkles. Under 2000x magnification, it could be observed that the outer shell of the capsule wall encapsulated some small capsule spheres, showing a multi-core structure, indicating that the Antarctic krill oil was successfully encapsulated into the capsule shell after gelation, emulsification, and spray drying with glyceryl laurate. Under 1000x magnification, the microcapsules of ungelled Antarctic krill oil prepared in Comparative Example 1 were less uniformly distributed and showed some aggregation, which may be due to adhesion caused by the high oil content on the capsule surface. A multi-core structure was not observed under 2000x magnification. Under 1000x magnification, the microcapsules prepared from Antarctic krill oil gelled with added glyceryl monostearate in Comparative Example 2 had a smoother surface, more intact capsule walls, and uniform distribution. However, no multinucleus structure was observed under 2000x magnification, 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 tested using an electronic nose, and the results are as follows: Figure 2 As shown. In contrast, the microcapsule sample of Antarctic krill oil gelled with added lauric acid monoglyceride in the example showed lower response values ​​on sensors W1C, W5S, W3C, W6S, W5C, W1S, W1W, W2S, W2W, and W3S than the microcapsule sample of ungelled Antarctic krill oil. This indicates that the former has lower concentrations of volatile substances such as aromatic hydrocarbons, nitrogen oxides, ammonia, hydrides, short-chain alkanes, methyl compounds, inorganic sulfides, alcohols, aldehydes, ketones, sulfides, and long-chain alkanes, resulting in better flavor quality. However, if glyceryl monostearate is used to prepare gelled Antarctic krill oil microcapsules, the response values ​​of the microcapsule samples on the W1C, W5S, W3C, W6S, W5C, W1S, W1W, W2S, W2W, and W3S sensors are much greater than those in Example 1 and Comparative Example 1. This indicates that the type of monostearate has a significant impact on the encapsulation effect of microcapsules and the release of flavor factors. Only by using glyceryl laurate to gel Antarctic krill oil and then emulsifying and spray-drying the emulsion mixed with the aqueous phase can the obtained microcapsules significantly improve the flavor quality.

[0055] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing gelled Antarctic krill oil microcapsules, characterized in that, Includes the following steps: S1. Preparation of core phase: Antarctic krill oil is mixed with monoglyceride, then stirred, cooled and allowed to stand to obtain Antarctic krill oil oil gel, which is used to prepare the core phase. The amount of monoglyceride added is 0.3~1.5g / kg Antarctic krill oil, and the cooling and standing is 10~12h at 2~5℃. S2. Preparation of wall material phase: Add the wall material to water while stirring to mix it evenly and obtain the wall material phase; S3. Preparation of gelled Antarctic krill oil crude emulsion: The core material phase obtained in step S1 is added to the wall material phase obtained in step S2, and the mixture is sheared and homogenized to obtain gelled Antarctic krill oil crude emulsion. S4. Preparation of gelled Antarctic krill oil fine emulsion: The gelled Antarctic krill oil crude emulsion obtained in step S3 is homogenized to obtain gelled Antarctic krill oil fine emulsion. S5. Preparation of gelled Antarctic krill oil microcapsules: The gelled Antarctic krill oil fine emulsion obtained in step S4 was spray-dried to obtain gelled Antarctic krill oil microcapsule powder. In step S1, the fatty acid carbon chain length of the monoglyceride is C12, and the monoglyceride is lauric acid monoglyceride.

2. The preparation method according to claim 1, characterized in that, In step S1, the stirring temperature is 60~80℃, the stirring speed is 200~500rpm, and the stirring time is 30~40min.

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

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

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

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

7. The preparation method according to claim 1, characterized in that, In step S5, the inlet air temperature of the spray dryer is 130~160℃, the outlet air temperature is 60~90℃, and the feed rate is 700~900mL / h.

8. Gel-coated Antarctic krill oil microcapsules prepared by the preparation method according to any one of claims 1 to 7.

9. The application of the gelled Antarctic krill oil microcapsules according to claim 8 in the food and pharmaceutical fields.

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