Nutritional medium chain triglyceride (MCT) microcapsule powder and preparation method thereof

Abstract

The invention discloses nutritional type medium chain triglyceride (MCT) micro-capsule powder and a preparation method thereof, the homogenizing pressure is 170-220 Mpa, and the nutritional type medium chain triglyceride (MCT) micro-capsule powder is prepared from the following raw materials in parts by weight: 233-900 parts of water, 65-75 parts of medium chain triglyceride (MCT), 10-30 parts of sodium caseinate, 10-30 parts of maltodextrin, 0.5-4 parts of mono / diglycerol fatty acid ester, 0.5-1.5 parts of silicon dioxide and 0.5-1.5 parts of dipotassium phosphate. MCT is used as a core material, protein and carbohydrate are compounded as a wall material, an aqueous phase and an oil phase are subjected to shear defoaming and high-pressure homogenization to obtain an emulsion, and a spray drying technology is adopted to prepare the medium-chain triglyceride microcapsule powder. The MCT microcapsule powder is good in embedding rate and low in surface oil content, the embedding effect of the microcapsule powder can be improved, and the shelf life of the microcapsule powder can be prolonged.

Description

Technical Field

[0001] The present invention relates to a microcapsule powder and a preparation method thereof, and particularly to a nutritional medium-chain triglyceride (MCT) microcapsule powder and a preparation method thereof. The present invention belongs to the technical field of special diets. Background Art

[0002] Due to their unique physical and chemical properties, oils and fats are difficult to store, transport, and use, especially some functional oils with physiological activity. Microencapsulation technology converts liquid or semi-solid oils and fats into powder form. This not only effectively protects the oils from damage by light, oxygen, and other factors, but also greatly facilitates their use in powdered products, such as as a fat source in dry-mixed, nutritionally complete formulas for special medical uses.

[0003] Traditional microencapsulation technology typically uses an oil loading between 10% and 60% by weight. With market development and increasing customer requirements, traditional low-oil-loading microencapsulation technologies are no longer able to meet market demands, resulting in emulsion stratification and high surface oil content. When the oil content is ≤ 60%, the active ingredient (oil) content in the microencapsulated powder is low, while the excipient content is high, inevitably leading to high microencapsulation costs. Most MCT microencapsulated powders on the market have a high carbohydrate content (≥ 30%) in their wall materials and use synthetic emulsifiers. This results in low nutritional value and may have adverse health effects, making them unsuitable as a fat component in special dietary supplements. Encapsulation efficiencies below 95% may affect the stability of the food system in which the microencapsulated powder is contained. For example, in a method for preparing a controlled energy supply medium-chain triglyceride microencapsulated powder, the encapsulation efficiency of MCT microcapsules ranged from 88.27% to 92.25%.

[0004] Commonly used polysaccharide wall materials for fat microcapsule powder in approved FSMPs include glucose syrup, maltodextrin, maltooligosaccharides, sodium starch glycolate octenylsuccinate, lactose, and solid corn syrup. Maltodextrin has high solubility, low viscosity, and a high oil-loading capacity. It is also readily available and thermally stable, which helps reduce production costs and makes it suitable for large-scale industrial production. Commonly used protein wall materials for fat microcapsule powder in approved FSMPs include whey protein, sodium caseinate, and whey protein isolate. Sodium caseinate has high solubility, good emulsification, a high oil-loading rate, and is easy to process. Therefore, maltodextrin and sodium caseinate are selected as wall materials to encapsulate MCT to increase the nutritional value and improve the quality of the fat microcapsule powder. Summary of the Invention

[0005] One of the objectives of this application is to provide a nutritional medium-chain triglyceride (MCT) microcapsule powder. By selecting highly nutritious sodium caseinate and maltodextrin as wall materials and optimizing the microcapsule powder wall material formulation, emulsifier dosage, and processing technology, the encapsulated fat content is approximately 65%-75%, the surface oil content is less than 5%, and the encapsulation efficiency reaches over 92.77%. The wall materials and emulsifiers used in this invention are both approved for use in special dietary supplements and are suitable as a fat source for special dietary supplements.

[0006] Another object of the present invention is to provide a method for preparing nutritional medium-chain triglyceride (MCT) microcapsule powder. The method uses MCT as a core material and a compound of protein and carbohydrates as a wall material. The aqueous phase and the oil phase are subjected to shear defoaming and high-pressure homogenization to obtain an emulsion. The spray drying technology is used to prepare the medium-chain triglyceride microcapsule powder, which has a good encapsulation rate and a low surface oil content. This can not only improve the encapsulation effect of the microcapsule powder, but also extend the shelf life of the microcapsule powder.

[0007] The present invention solves the technical problem by adopting the following technical solutions: The present invention first provides a nutritional medium-chain triglyceride (MCT) microcapsule powder with a homogenization pressure of 170-220 MPa. The powder comprises the following raw materials by weight: 233-900 parts of water, 65-75 parts of medium-chain triglycerides (MCT), 10-30 parts of sodium caseinate, 10-30 parts of maltodextrin, 0.5-4 parts of mono- and diglycerol fatty acid esters, 0.5-1.5 parts of silicon dioxide, and 0.5-1.5 parts of dipotassium hydrogen phosphate.

[0008] In the above technical solution, the amount of water added is preferably 350-450 parts.

[0009] In the above technical solution, the mono- and di-glycerol fatty acid esters are preferably 0.9-1.5 parts; the mono- and di-glycerol fatty acid esters are food emulsifiers, and the food label is E471.

[0010] In the above technical solution, the maltodextrin is preferably dissolved maltodextrin.

[0011] The present invention also provides a method for preparing the nutritional medium-chain triglyceride (MCT) microcapsule powder, comprising the following steps: Step (1): First, dissolve 10-30 parts of maltodextrin, 10-30 parts of sodium caseinate and 0.5-1.5 parts of dipotassium hydrogen phosphate in 233-900 parts of 55-65°C water in sequence with stirring, adjust the pH of the system to 6.5-7.5, and keep stirring for 4-6 minutes to prepare liquid A for use; Step (2): Heat 65-75 parts of medium chain triglycerides (MCT) to 55-65°C, add 0.5-4 parts of mono- and diglycerol fatty acid esters, and stir for 4-6 minutes to prepare liquid B for later use; Step (3): slowly and uniformly adding the liquid A obtained in step (1) to the liquid B obtained in step (2) to mix them to obtain a mixed solution; Step (4): The mixed solution obtained in step (3) is subjected to high-speed homogenization at a rotation speed of 15,000 r / min for 5 minutes, and the homogenized mixed solution is subjected to high-pressure homogenization for 3 cycles at a pressure of 170-220 MPa to obtain a high-pressure homogenized mixed solution; Step (5): spray-drying the high-pressure homogenized mixed solution obtained in step (4) to obtain a powder, and mixing the powder with 0.5-1.5 parts of silicon dioxide to prepare MCT microcapsule powder, that is, obtaining the nutritional medium-chain triglyceride (MCT) microcapsule powder.

[0012] In the above technical solution, in step (1), the maltodextrin and sodium caseinate are wall materials; the weight addition ratio of the maltodextrin and sodium caseinate is 3:1, 2:1, 1:1, 1:2, and 1:3.

[0013] In the above technical solution, in step (1), the weight ratio of maltodextrin and sodium caseinate added is preferably 1:1 and 2:1.

[0014] In the above technical solution, in step (5), when spray drying is performed, the inlet air temperature is 180°C, the outlet air temperature is 85±5°C, and the feed liquid flow rate is 1.5 L / h.

[0015] Compared with the prior art, the present invention has at least the following advantages or beneficial effects: First, the present invention provides a nutritional MCT microcapsule powder. By selecting highly nutritious sodium caseinate and maltodextrin as wall materials and optimizing the microcapsule powder wall material formulation, emulsifier dosage, and processing technology, the encapsulated fat content is approximately 65%-75%, the surface oil content is less than 5%, and the encapsulation efficiency reaches over 92.77%. The wall materials and emulsifiers used in the present invention are both approved for use in special dietary supplements, making them suitable as a fat source for special dietary supplements.

[0016] Second, the present invention provides a method for preparing nutritional MCT microcapsule powder, which uses MCT as the core material and a compound of protein and carbohydrates as the wall material. The aqueous phase and the oil phase are subjected to shear defoaming and high-pressure homogenization to obtain an emulsion. The spray drying technology is used to prepare the MCT microcapsule powder with a good embedding rate and low surface oil content, which can not only improve the embedding effect of the microcapsule powder, but also extend the shelf life of the microcapsule powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is to verify the scanning electron microscope image of the nutritional MCT microcapsule powder obtained in Example 1.

[0018] Figure 2 To verify the effect of different wall material ratios on sample particle size and Zeta potential in Example 3; Figure 2 A is the effect of different wall material ratios on sample particle size. Figure 2 B is the average value of Zeta potential of samples prepared with different wall material ratios. Figure 2 C is the Zeta potential diagram of samples prepared with different wall material ratios; Figure 3 To verify the effect of different mono- and diglycerol fatty acid ester contents on sample particle size and Zeta potential in Example 4; wherein: Figure 3 A is the effect of different mono- and diglycerol fatty acid ester contents on sample particle size. Figure 3 B is the average value of Zeta potential of samples prepared with different mono- and diglycerol fatty acid ester contents. Figure 3 C is the Zeta potential diagram of samples prepared with different mono- and diglycerol fatty acid ester contents; Figure 4 To verify the effect of different solid contents on sample particle size and Zeta potential in Example 5; wherein: Figure 4 A is the effect of different solid contents on sample particle size. Figure 4 B is the average Zeta potential diagram of samples prepared with different solid contents. Figure 4 C is the Zeta potential diagram of samples prepared with different solid contents; Figure 5 To verify the effect of different wall material ratios on the grease embedding rate of the sample in Example 7; Figure 6 To verify the effect of different mono- and diglycerol fatty acid ester contents on the oil embedding efficiency of the sample in Example 8; Figure 7 To verify the effect of different solid contents on the oil embedding efficiency of the sample in Example 9; DETAILED DESCRIPTION

[0019] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0020] The invention provides a nutritional MCT microcapsule powder having a homogenization pressure of 170-210 MPa and comprising the following raw materials in parts by weight: 233-900 parts of water, 65-75 parts of MCT, 10-30 parts of sodium caseinate, 10-30 parts of maltodextrin, 0.5-4 parts of mono- and diglycerol fatty acid esters, 0.5-1.5 parts of silicon dioxide, and 0.5-1.5 parts of dipotassium hydrogen phosphate.

[0021] In some embodiments of the present invention, the following raw materials are included by weight: 70 parts of MCT, 15 parts of maltodextrin, 15 parts of sodium caseinate, 1 part of dipotassium hydrogen phosphate, 1 part of mono- and diglycerol fatty acid esters, and 1 part of silicon dioxide.

[0022] In some embodiments of the present invention, the following raw materials are included by weight: 70 parts of MCT, 20 parts of maltodextrin, 10 parts of sodium caseinate, 1 part of dipotassium hydrogen phosphate, 1 part of mono- and diglycerol fatty acid esters, and 1 part of silicon dioxide.

[0023] In some embodiments of the present invention, the following raw materials are included by weight: 70 parts of MCT, 15 parts of maltodextrin, 15 parts of sodium caseinate, 1 part of dipotassium hydrogen phosphate, 1 part of mono- and diglycerol fatty acid esters, and 1 part of silicon dioxide.

[0024] The present application will be described in detail below with reference to specific embodiments.

[0025] In the following examples of the present invention, the MCT used is easier to digest and absorb. MCT has a low dependence on bile salts and pancreatic enzymes and is easily hydrolyzed in the intestine. The resulting medium-chain fatty acids (MCFAs) have short carbon chains and are easily and rapidly absorbed. MCFAs are digested four times faster than ordinary long-chain fatty acids and metabolized ten times faster. After absorption, MCFAs bind to albumin and are directly transported to the liver via the portal vein, eliminating the need to form chylomicrons and participating in peripheral circulation. This allows for easy absorption and rapid conversion to energy in the liver, providing energy for the body without contributing to fat accumulation. Furthermore, MCFAs do not rely on carnitine and directly enter the mitochondria of hepatocytes for β-oxidation. This rapid and complete oxidation makes them less likely to accumulate in adipose tissue and liver tissue. Studies have shown that MCFA intake can improve energy metabolism and promote lipolysis. The rapid metabolism of MCFAs can also help stabilize blood sugar levels, reduce insulin fluctuations, and facilitate blood sugar management, which may be beneficial for people with diabetes or reduced insulin sensitivity. Finally, MCFAs have certain antibacterial and antiviral properties, which can inhibit the growth of certain pathogenic microorganisms, help maintain a healthy intestinal balance, and contribute to a healthy digestive system.

[0026] In the following examples of the present invention, maltodextrin, containing a large amount of polysaccharides, is a widely used basic raw material in the food industry, possessing excellent properties and serving as the primary source of carbohydrate energy in formulations. Maltodextrin also exhibits favorable physical and chemical properties, including water solubility, good fluidity, low hygroscopicity, low sweetness, and moderate viscosity. Furthermore, with a DE value of 13%-17%, it exhibits resistance to moisture, a low proportion of reducing sugars, and resistance to browning. Maltodextrin can also be used as a wall material for nanoemulsions and microcapsules, providing excellent protection for encapsulated contents.

[0027] In the following examples of the present invention, sodium caseinate is the sodium salt form of casein (the main protein in milk). It has excellent solubility, emulsification, and stability. Because sodium caseinate contains various essential amino acids, it has high nutritional value and can also be used as a nutritional supplement. As a food additive, sodium caseinate is highly safe and is widely approved for use worldwide. Its excellent emulsification and thickening properties make it widely used in almost all food industries.

[0028] In the following examples of the present invention, dipotassium hydrogen phosphate is used. It is an inorganic compound with the chemical formula K2HPO4. It is a white crystalline or amorphous powder that is readily soluble in water. It is a common food additive widely used in food processing, primarily as a buffer, emulsifier, and stabilizer. Dipotassium hydrogen phosphate can adjust the pH value of food, acting as a buffer to help maintain the acid-base balance of food and prevent acidification or alkalization that affects flavor and texture.

[0029] In the following embodiments of the present invention, the mono- and diglycerol fatty acid esters used are the most widely used food emulsifiers and can stabilize the oil-water mixture and prevent stratification.

[0030] The features and performance of the present application are further described in detail below with reference to the embodiments. Example 1

[0031] This embodiment provides a nutritional MCT microcapsule powder, which includes the following raw materials, by weight: 70 parts of MCT, 15 parts of maltodextrin, 15 parts of sodium caseinate, 1 part of dipotassium hydrogen phosphate, 1 part of mono- and diglycerol fatty acid esters, and 1 part of silicon dioxide.

[0032] The nutritional MCT microcapsule powder is prepared by the following preparation method: Step (1): First, dissolve 15 parts of maltodextrin, 15 parts of sodium caseinate and 1 part of dipotassium hydrogen phosphate in 400 parts of deionized water at 60°C in sequence, and keep stirring for 10 minutes to prepare liquid A for standby use; in this embodiment, the ratio of maltodextrin to sodium caseinate is 1:1; Step (2): Heat the MCT to 60°C, add 1 part of mono- and diglycerol fatty acid esters, and stir for 10 minutes to prepare liquid B; Step (3): slowly and uniformly add liquid A to liquid B to obtain a mixed solution; Step (4): The mixed solution was subjected to high-speed homogenization at a speed of 15,000 r / min for 5 min, and the homogenized mixed solution was subjected to high-pressure homogenization at a pressure of 210 MPa for 3 cycles; Step (5): spray-dry the mixed solution after high-pressure homogenization to obtain a powder, and mix it with 1 part of silicon dioxide to prepare MCT microcapsule powder to obtain the nutritional MCT microcapsule powder. The inlet air temperature of the spray drying is 180°C, the outlet air temperature is 85±5°C, and the feed liquid flow rate is 1.5 L / h. Example 2

[0033] This embodiment provides a nutritional MCT microcapsule powder, which includes the following raw materials, by weight: 70 parts of MCT, 20 parts of maltodextrin, 10 parts of sodium caseinate, 1 part of dipotassium hydrogen phosphate, 1 part of mono- and diglycerol fatty acid esters, and 1 part of silicon dioxide.

[0034] The nutritional MCT microcapsule powder is prepared by the following preparation method: Step (1): First, dissolve 20 parts of maltodextrin, 10 parts of sodium caseinate and 1 part of dipotassium hydrogen phosphate in 400 parts of deionized water at 60°C in sequence, and keep stirring for 10 minutes to prepare liquid A for use; in this embodiment, the ratio of maltodextrin to sodium caseinate is 2:1; Step (2): Heat the MCT to 60°C, add 1 part of mono- and diglycerol fatty acid esters, and stir for 10 minutes to prepare liquid B; Step (3): slowly and uniformly add liquid A to liquid B to obtain a mixed solution; Step (4): The mixed solution was subjected to high-speed homogenization at a speed of 15,000 r / min for 5 min, and the homogenized mixed solution was subjected to high-pressure homogenization at a pressure of 210 MPa for 3 cycles; Step (5): spray-dry the mixed solution after high-pressure homogenization to obtain a powder, and mix it with 1 part of silicon dioxide to prepare MCT microcapsule powder to obtain the nutritional MCT microcapsule powder. The inlet air temperature of the spray drying is 180°C, the outlet air temperature is 85±5°C, and the feed liquid flow rate is 1.5 L / h. Example 3

[0035] This embodiment provides a nutritional MCT microcapsule powder, which includes the following raw materials, by weight: 70 parts of MCT, 15 parts of maltodextrin, 15 parts of sodium caseinate, 1 part of dipotassium hydrogen phosphate, 1 part of mono- and diglycerol fatty acid esters, and 1 part of silicon dioxide.

[0036] The nutritional MCT microcapsule powder is prepared by the following preparation method: Step (1): First, dissolve 15 parts of maltodextrin, 15 parts of sodium caseinate and 1 part of dipotassium hydrogen phosphate in 400 parts of deionized water at 60°C in sequence, and keep stirring for 10 minutes to prepare liquid A for use; in this embodiment, the ratio of maltodextrin to sodium caseinate is 1:1; Step (2): Heat the MCT to 60°C, add 1 part of mono- and diglycerol fatty acid esters, and stir for 10 minutes to prepare liquid B; Step (3): slowly and uniformly add liquid A to liquid B to obtain a mixed solution; Step (4): The mixed solution was subjected to high-speed homogenization at a speed of 15,000 r / min for 5 min, and the homogenized mixed solution was subjected to high-pressure homogenization at a pressure of 170 MPa for 3 cycles; Step (5): spray-dry the mixed solution after high-pressure homogenization to obtain a powder, and mix it with 1 part of silicon dioxide to prepare MCT microcapsule powder to obtain the nutritional MCT microcapsule powder. The inlet air temperature of the spray drying is 180°C, the outlet air temperature is 85±5°C, and the feed liquid flow rate is 1.5 L / h.

[0037] Comparative Example 1 The method is basically the same as Example 1, except that in step (1), the amount of maltodextrin is 10 parts and the amount of sodium caseinate is 20 parts. In this embodiment, the ratio of maltodextrin to sodium caseinate is 1:2.

[0038] Comparative Example 2

[0039] The method is basically the same as Example 1, except that the amount of monoglycerol and diglycerol fatty acid esters in step (2) is 3 parts.

[0040] Verification Example 1: Morphological Features

[0041] The surface structure of the MCT microcapsule powder obtained in Example 1 was observed using a scanning electron microscope. Figure 1 As shown: Depend on Figure 1The MCT microcapsules obtained through spray drying exhibited a nearly spherical structure of varying sizes, endowing the product with excellent dispersibility and flowability. The surface of the MCT microcapsules was smooth and intact, with minimal cracking, which helped prevent oxygen penetration and ensured excellent encapsulation. At a magnification of 5000x, irregular wrinkles were clearly observed on the surface of the microcapsules, likely due to the high protein content. Rapid water evaporation during the drying process caused the protein shell to shrink rapidly.

[0042] Verification Example 2: Method for Determining Particle Size and Potential of MCT Microcapsule Powder Reconstituted Emulsion

[0043] The particle size distribution and zeta potential of the samples were measured using a nanoparticle size and zeta potential analyzer. Before measurement, a certain mass of microcapsule powder sample was weighed and dissolved in deionized water at a 1:1000 (w / v) ratio to avoid multiple scattering effects. The refractive index of the dispersant (deionized water) was 1.33. Three samples were randomly tested in each group for Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2, and the average results were calculated. Table 1 shows the results.

[0044] Table 1 shows the particle size and potential results of MCT microcapsule powder sample Particle size (d. nm) Potential (mV) Example 1 295.94 ± 3.09 -51.12 ± 0.44 Example 2 338.31 ± 6.64 -51.23 ± 0.42 Example 3 334.50 ± 10.18 -50.80 ± 0.39 Comparative Example 1 390.47 ± 44.94 -50.01 ± 0.51 Comparative Example 2 412.86 ± 16.97 -49.49 ± 0.48 From the results in Table 1, it can be seen that the particle size of the embodiment is between 295 and 339 d.nm, and the potential is between -50.8 and -51.3 mV. The particle size of the microcapsules after redissolution is small, and the system is stable.

[0045] Verification Example 3: Effect of Wall Material Ratio on Sample Particle Size and Zeta Potential

[0046] The ratio of maltodextrin to sodium caseinate in the sample of Example 1 was 1:1, the ratio of maltodextrin to sodium caseinate in the sample of Example 2 was 2:1, and the ratio of maltodextrin to sodium caseinate in the sample of Comparative Example 1 was 1:2. Samples with maltodextrin to sodium caseinate ratios of 3:1 and 1:3 were prepared by referring to the method of Example 1.

[0047] The samples with the ratio of maltodextrin to sodium caseinate of 1:1, 2:1, 1:2, 3:1 and 1:3 were used as research objects. The effect of the ratio of wall materials on the particle size and Zeta potential of the samples was studied by referring to the method of Example 2. The results are as follows: Figure 2 As shown by Figure 2It can be seen that when the mass ratio of maltodextrin to sodium caseinate is 3:1, 1:2, and 1:3, the particle size shows a bimodal distribution. When the mass ratio is 2:1 and 1:1, the particle size shows a unimodal distribution, and the particle size distribution is more concentrated. With the increase of the amount of sodium caseinate added, the particle size first decreases and then increases. When the ratio of maltodextrin to sodium caseinate is 1:1 and 2:1, the average particle size is small, ranging from 250 nm to 350 nm. The absolute value of the zeta potential gradually decreases, but the absolute value is greater than 48 mV, indicating that all groups of samples are uniform and stable.

[0048] Verification Example 4: Effect of Mono- and Diglycerol Fatty Acid Ester Content on Sample Particle Size and Zeta Potential

[0049] The content of mono- and diglycerol fatty acid esters in the MCT microcapsule powder obtained in Example 1 was 0.97% (approximately 1%). Referring to the method of Example 1, samples with mono- and diglycerol fatty acid ester contents of 0.5%, 2%, 3% and 4% were prepared respectively.

[0050] The samples with the above-mentioned mono- and diglycerol fatty acid ester contents of 0.5%, 1%, 2%, 3% and 4% were used as research objects, and the effect of the mono- and diglycerol fatty acid ester contents on the particle size and Zeta potential of the samples was studied with reference to the method of Verification Example 2. The results are as follows: Figure 3 As shown by Figure 3 As can be seen, when the mono- and diglycerol fatty acid ester content is 1%, the particle size distribution is relatively concentrated. As the emulsifier addition level continues to increase, the peak of the particle size distribution gradually shifts to the right. The average particle size decreases first, then increases, and then stabilizes as the mono- and diglycerol fatty acid ester content increases from 0.5% to 4%. The absolute value of the potential increases first, then decreases, with increasing emulsifier content. This may be due to excessive emulsifier addition, which causes the previously stable network structure within the emulsion system to aggregate, increasing the viscosity of the system and leading to a decrease in emulsion stability. When the mono- and diglycerol fatty acid ester content is 1%, the absolute value of the potential is the highest (51.12 ± 0.44 mV), indicating the best stability of the system.

[0051] Verification Example 5: Effect of Solids Content on Sample Particle Size and Zeta Potential

[0052] First, the solid content refers to all raw materials in the formula except water. The solid content obtained in Example 1 is 20%. Referring to the method of Example 1, samples with solid contents of 10%, 15%, 20%, 25%, and 30% were prepared respectively.

[0053] The samples with solid contents of 10%, 15%, 20%, 25%, and 30% were used as research objects, and the effect of solid content on the particle size and Zeta potential of the samples was studied by referring to the method of Verification Example 2. The results are as follows: Figure 4 As shown by Figure 4 As can be seen, when the solids content is 20%, the particle size distribution is unimodal, while the particle size distributions of the other groups are bimodal. As the solids content increases from 10% to 30%, the particle size first decreases and then increases. At 20% solids content, the average particle size is the smallest (295.94 ± 3.09 d.nm), a decrease of 109.13 d.nm compared to the average particle size at 15% solids content (405.07 ± 55.29 d.nm). The average particle sizes at 25% and 30% solids contents are 692.90 ± 49.58 d.nm and 913.30 ± 78.51 d.nm, respectively, approximately twice and three times the average particle size at 20%, indicating that the reduction in water content has a significant impact on the system. The absolute value of the potential first increases and then decreases with the increase of solid content. When the solid content is 20%, the absolute value of the potential is the largest (51.12 ± 0.44 mV), and the system is more stable than under other conditions.

[0054] Verification Example 6: Method for Determining the Embedding Efficiency of MCT Microcapsule Powder:

[0055] (1) Surface oil: Dry the beaker in a 105°C oven for 1 h, remove it and cool it in a desiccator for 30 min, weigh m1 and set aside. Add 15 mL of petroleum ether to 2.5 g (m) microcapsule powder and shake it for 5 min. Filter and collect the filtrate in a beaker that has been constant weighted. Transfer the filter residue to a conical flask and shake and extract it twice with 15 mL of petroleum ether. Evaporate the petroleum ether in the filtrate in a 60°C water bath. Finally, dry it in a 105°C oven for 3 h. Cool it in a desiccator for 30 min and weigh m2.

[0056] Calculate the surface oil content according to the formula:

[0057] (2) Determination of total oil: Dry the beaker in a 105°C oven for 1 hour, remove it and cool it in a desiccator for 30 minutes, weigh M1 and set aside. Add 10 mL of hydrochloric acid to 2 g of (M) microcapsule powder and place it in a 70°C water bath for 40 minutes, taking it out and shaking it every 10 minutes. After the water bath, add 15 mL of petroleum ether and vortex for 2 minutes. Use a separatory funnel to separate the layers and collect the ether solution in a constant weight beaker. Repeat this twice. Evaporate the organic reagent in the filtrate in a 60°C water bath. Finally, dry it in a 105°C oven for 3 hours, cool it in a desiccator for 30 minutes, and weigh M2.

[0058] Refer to the formula to calculate the total oil content:

[0059] Calculate the embedding rate according to the formula:

[0060] Three samples were randomly tested in each group of Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2, and the average value was taken. The results are shown in Table 2.

[0061] Table 2 Test results of surface oil content and embedding efficiency of MCT microcapsule powder sample Surface oil content (%) Embedding rate (%) Example 1 1.19 ± 0.40 98.24 ± 0.02 Example 2 4.91 ± 1.20 92.77 ± 0.02 Example 3 3.99 ± 0.83 94.10 ± 0.06 Comparative Example 1 10.47 ± 1.25 84.56 ± 0.11 Comparative Example 2 14.42 ± 0.50 78.14 ± 0.17 From the results in Table 2, it can be seen that the surface oil content of the embodiments is between 1% and 5%, and the embedding efficiency is between 92% and 98%. The microcapsules have a lower surface oil content and a higher embedding efficiency, and the embedding effect is better.

[0062] Verification Example 7: Effect of Wall Material Ratio on Sample Grease Embedding Rate

[0063] The above samples with maltodextrin: sodium caseinate ratios of 1:1, 2:1, 1:2, 3:1 and 1:3 were used as research objects. The effect of the wall material ratio on the oil embedding efficiency of the samples was studied with reference to the method of Example 6. The results are as follows: Figure 5 As shown by Figure 5 It can be seen that when the ratio of maltodextrin to sodium caseinate is 1:1, the surface oil content of the sample is the lowest and the embedding rate is the highest.

[0064] Verification Example 8: Effect of solid content on sample oil embedding efficiency

[0065] The samples with the above-mentioned mono- and diglycerol fatty acid ester contents of 0.5%, 1%, 2%, 3% and 4% were used as research objects. The effect of the mono- and diglycerol fatty acid ester contents on the oil embedding efficiency of the samples was studied with reference to the method of Verification Example 6. The results are as follows: Figure 6 As shown by Figure 6 It can be seen that when the content of mono- and diglycerol fatty acid esters is 1%, the surface oil content of the sample is the lowest and the embedding rate is the highest.

[0066] Verification Example 9: Effect of Mono- and Diglycerol Fatty Acid Ester Content on Sample Oil Embedding Efficiency

[0067] First, the solid content refers to all raw materials except water. Referring to the method of Example 1, samples with solid contents of 10%, 15%, 20%, 25%, and 30% were prepared respectively.

[0068] The above samples with solid contents of 10%, 15%, 20%, 25%, and 30% were used as research objects, and the effect of solid content on the oil embedding efficiency of the samples was studied with reference to the method of Verification Example 6. The results are as follows: Figure 7 As shown by Figure 7 It can be seen that when the solid content is 20%, the sample surface oil content is the lowest and the embedding rate is the highest.

[0069] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A nutritional medium-chain triglyceride microcapsule powder, having a homogenization pressure of 170-220 MPa, characterized in that: The invention comprises the following raw materials in parts by weight: 233-900 parts of water, 65-75 parts of medium chain triglycerides, 10-30 parts of sodium caseinate, 10-30 parts of maltodextrin, 0.5-4 parts of mono- and diglycerol fatty acid esters, 0.5-1.5 parts of silicon dioxide and 0.5-1.5 parts of dipotassium hydrogen phosphate.

2. The nutritional medium-chain triglyceride microcapsule powder according to claim 1, characterized in that: The amount of water added is 350-450 parts.

3. The nutritional medium-chain triglyceride microcapsule powder according to claim 1, characterized in that: The monoglyceride and diglyceride fatty acid esters are 0.9-1.5 parts; the monoglyceride and diglyceride fatty acid esters are food emulsifiers, and the food label is E471.

4. The nutritional medium-chain triglyceride microcapsule powder according to claim 1, characterized in that: The maltodextrin is dissolved maltodextrin.

5. A method for preparing the nutritional medium-chain triglyceride microcapsule powder according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step (1): First, dissolve 10-30 parts of maltodextrin, 10-30 parts of sodium caseinate and 0.5-1.5 parts of dipotassium hydrogen phosphate in 233-900 parts of 55-65°C water in sequence with stirring, adjust the pH of the system to 6.5-7.5, and keep stirring for 4-6 minutes to prepare liquid A for use; Step (2): Heat 65-75 parts of medium chain triglycerides (MCT) to 55-65°C, add 0.5-4 parts of mono- and diglycerol fatty acid esters, and stir for 4-6 minutes to prepare liquid B for later use; Step (3): slowly and uniformly adding the liquid A obtained in step (1) to the liquid B obtained in step (2) to mix them to obtain a mixed solution; Step (4): The mixed solution obtained in step (3) is subjected to high-speed homogenization at a rotation speed of 15,000 r / min for 5 minutes, and the homogenized mixed solution is subjected to high-pressure homogenization for 3 cycles at a pressure of 170-220 MPa to obtain a high-pressure homogenized mixed solution; Step (5): spray-drying the high-pressure homogenized mixed solution obtained in step (4) to obtain a powder, and mixing the powder with 0.5-1.5 parts of silicon dioxide to prepare MCT microcapsule powder, that is, obtaining the nutritional medium-chain triglyceride (MCT) microcapsule powder.

6. The preparation method according to claim 5, characterized in that In step (1), the maltodextrin and sodium caseinate are used as wall materials; the weight addition ratio of the maltodextrin and sodium caseinate is 3:1, 2:1, 1:1, 1:2, and 1:

3.

7. The preparation method according to claim 6, characterized in that The weight addition ratio of the maltodextrin and sodium caseinate is 1:1 and 2:

1.

8. The preparation method according to claim 5, characterized in that In step (5), when spray drying is performed, the inlet air temperature is 180°C, the outlet air temperature is 85±5°C, and the feed liquid flow rate is 1.5 L / h.

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