Diglyceride microcapsule powdered oil as well as preparation method and application thereof

Abstract

The invention relates to microcapsule powdered oil as well as a preparation method and application thereof. The microcapsule powdered oil comprises the following raw material components in percentage by mass: 82%-92% of oil, 5%-15% of a wall material and 1%-3% of an emulsifier, and the mass content of diglyceride in the oil is not less than 80%; the wall material is formed by compounding sodium caseinate, starch sodium octenylsuccinate, maltodextrin and whey protein, and the mass ratio of the whey protein in the wall material is greater than or equal to 50%; the emulsifier is formed by compounding polyglycerol fatty acid ester, mono-glycerol fatty acid ester, diglycerol fatty acid ester and sucrose fatty acid ester; the preparation method of the microcapsule powdered oil of diglyceride comprises the step of gradient temperature control ultrasonic treatment. According to the invention, the microcapsule powdered oil of diglyceride with high oil content, high embedding rate and small particle size is prepared through cooperation of the specific compounded wall material and the emulsifier and the gradient temperature control ultrasound, and the technical problem that high oil content, high embedding rate and small particle size cannot be realized at the same time is solved.

Description

Technical Field

[0001] This invention belongs to the field of food technology and relates to the processing of foods for special medical purposes and functional oils, specifically to a microcapsule powder oil of diglycerides, its preparation method and application. Background Technology

[0002] As a functional oil, diglycerides (DAG) have a different metabolic pathway than traditional triglycerides. They have advantages such as rapid energy supply and reduced body fat accumulation, making them suitable for special medical food scenarios that require rapid energy support, such as postoperative rehabilitation and nutritional intervention for severe wasting diseases.

[0003] However, when applying liquid diglycerides to powdered medical food formulations, microencapsulation technology is typically required to convert them into solid powder. Furthermore, the non-complete nutritional fat components in medical foods need high energy density (oil content ≥70%) to reduce the amount ingested per dose and lower the metabolic burden on patients. However, current technologies, to avoid oil droplet fusion and oxidation, typically control the oil content at 40%–60%, resulting in insufficient energy density. Forcibly increasing the oil content would reduce the encapsulation efficiency to below 90% (e.g., the encapsulation efficiency is only 88.5% with an oil content of 72% as disclosed in CN 115336637 A). Increased surface oil content makes them prone to oxidation, failing to meet the storage stability requirements of medical foods.

[0004] Therefore, the diglyceride microcapsule powder oils prepared by current technologies cannot simultaneously achieve high oil content and high encapsulation rate, and cannot simultaneously meet the requirements of high energy density and storage stability of special medical foods. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a glycerol diglyceride microcapsule powder oil with both high oil content and high encapsulation rate, and a method for preparing the same.

[0006] The technical solutions for achieving the above objectives include the following.

[0007] In a first aspect, the present invention provides a microcapsule powdered oil, wherein, by mass percentage, the raw material components of the microcapsule powdered oil include: 82%–92% oil, 5%–15% wall material, and 1%–3% emulsifier, wherein the mass content of diglycerides in the oil is not less than 80%;

[0008] The wall material is composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein, and the whey protein in the wall material accounts for ≥50% by mass.

[0009] The emulsifier is a compound of polyglycerol fatty acid esters, mono- and diglycerol fatty acid esters and sucrose fatty acid esters;

[0010] The preparation method of the microcapsule powder oil of the diglyceride includes a gradient temperature controlled ultrasound step: the crude emulsion made of the oil, wall material and emulsifier is ultrasonically treated under gradient temperature controlled conditions, the gradient temperature controlled conditions are: first treated at 100W to 150W for 0.5min to 3min, then increased to 200W to 250W for 1min to 5min, and finally increased to 300W to 400W for 1min to 5min, and the emulsion temperature is kept below 40℃ during the treatment.

[0011] Secondly, the present invention provides a method for preparing the microcapsule powder oil, comprising the following steps:

[0012] (1) Dissolve the wall material in water to obtain a stable aqueous solution; heat and melt the oil and emulsifier to obtain an oil solution;

[0013] (2) The aqueous solution is added to the oil solution and sheared and dispersed to obtain a crude emulsion;

[0014] (3) The crude emulsion is subjected to ultrasonic treatment under gradient temperature control to obtain a fine emulsion; the gradient temperature control conditions are: first, treat with 100W~150W for 0.5min~3min, then increase to 200W~250W for 1min~5min, and finally increase to 300W~400W for 1min~5min, and keep the emulsion temperature below 40℃ during the treatment process;

[0015] (4) The fine emulsion is homogenized under high pressure to obtain a homogenized emulsion;

[0016] (5) The homogenized emulsion is spray-dried to obtain the microcapsule powder oil.

[0017] Thirdly, the present invention provides the application of the aforementioned microcapsule powder oil as a special oil for rapid energy supply or in the preparation of foods for special medical purposes.

[0018] The present invention has the following beneficial effects:

[0019] This invention utilizes a specific compound wall material (sodium caseinate, sodium octenyl succinate starch, maltodextrin, and whey protein, with whey protein comprising ≥50% by mass) and a specific emulsifier (polyglycerol fatty acid esters, mono- and diglycerol fatty acid esters, and sucrose fatty acid esters) combined with a gradient low-temperature ultrasonic preparation method to synergistically prepare microcapsule powder oils with high oil content, high encapsulation efficiency, and small particle size of diglycerides. This solves the technical challenge of simultaneously achieving high oil content, high encapsulation efficiency, and small particle size in existing technologies. The microcapsule powder oils prepared by this invention enable the high-content diglycerides to provide direct energy through the portal vein, while the small particle size of the microcapsules promotes digestion and absorption. This effectively meets the specific medical needs of patients in postoperative recovery, weakness, and hypermetabolic states for rapid energy replenishment.

[0020] The synergistic system of this invention not only withstands the physicochemical effects of the ultrasonic process but also produces a synergistic effect, forming a more robust and dense interfacial film with the help of ultrasound. This allows for the preparation of high-performance medical food oil powders under extremely high-fat conditions. This invention promotes the uniform adsorption of the wall material on the surface of small oil droplets and the formation of a stable interfacial film through ultrasonic treatment, effectively reducing the microcapsule particle size and inhibiting oil droplet aggregation. This increases the specific surface area of ​​the reconstituted emulsion, enabling rapid dispersion and release of oils in water. This satisfies both the long-term storage requirements for oxidative stability in medical foods and the rapid energy supply needs of post-operative, weakened, and hypermetabolic individuals. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more complete description will be provided below. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0022] Unless otherwise specified, experimental methods in the following examples are generally performed under standard conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the examples are commercially available products.

[0023] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0024] Furthermore, as used herein, the term "or" is an inclusive "or" sign and is equivalent to the term "and / or" unless the context clearly specifies otherwise. The term "based on" is not exclusive and allows for basing on other factors not described unless the context clearly specifies otherwise. Additionally, throughout the specification, the meanings of "an," "a," and "the" include plural indicators. The meaning of "in" includes both "in" and "on."

[0025] Some embodiments of the present invention relate to a microcapsule powdered oil, wherein, by mass percentage, the raw material components of the microcapsule powdered oil include: 82%–92% oil, 5%–15% wall material, and 1%–3% emulsifier, wherein the mass content of diglycerides in the oil is not less than 80%;

[0026] The wall material is composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein, and the whey protein in the wall material accounts for ≥50% by mass.

[0027] The emulsifier is a compound of polyglycerol fatty acid esters, mono- and diglycerol fatty acid esters and sucrose fatty acid esters;

[0028] The preparation method of the microcapsule powder oil of the diglyceride includes a gradient temperature controlled ultrasound step: the crude emulsion made of the oil, wall material and emulsifier is ultrasonically treated under gradient temperature controlled conditions, the gradient temperature controlled conditions are: first treated at 100W to 150W for 0.5min to 3min, then increased to 200W to 250W for 1min to 5min, and finally increased to 300W to 400W for 1min to 5min, and the emulsion temperature is kept below 40℃ during the treatment.

[0029] In some embodiments, the raw material components of the microcapsule powder oil include: 85%–90% oil, 8%–12% wall material, and 1%–3% emulsifier.

[0030] In some embodiments, the whey protein content in the wall material is 50%~54% by mass, more preferably 50%~52%, and even more preferably 50%. This invention controls the whey protein content to be ≥50%, and more preferably 50%~54%. At this ratio, the natural emulsifying properties of whey protein can synergistically form a dense protein-polysaccharide composite interface film with ultrasonic cavitation, which is key to achieving a high encapsulation rate.

[0031] In some embodiments, the mass ratio of sodium caseinate, sodium octenyl succinate starch, maltodextrin, and whey protein in the wall material is 0.5–1.5:0.5–1.5:0.5–1.5:2–4, preferably 1:0.8–1.2:0.8–1.2:2.5–3.5, more preferably 1:0.9–1.1:0.9–1.1:2.5–3.5, even more preferably 1:0.9–1.1:0.9–1.1:2.9–3.2, even more preferably 1:1:1:2.5–3.5, even more preferably 1:1:1:2.9–3.2, and even more preferably 1:1:1:3.

[0032] In some embodiments, the oil contains 80%-85% diglycerides by mass.

[0033] In some embodiments, the fat contains 50% to 60% by mass of fatty acids with a carbon chain length of 8–12, and the fat contains 9% to 14% by mass of unsaturated fatty acids.

[0034] In some embodiments, the fat contains 54% to 56% by mass of fatty acids with a carbon chain length of 8–12, and the fat contains 10% to 12% by mass of unsaturated fatty acids.

[0035] In some embodiments, the lauric acid content in the oil is 40% to 45% of the total fatty acids.

[0036] In some embodiments, the oil is coconut diglyceride oil.

[0037] In some embodiments, the oil is walnut diglyceride oil.

[0038] In some embodiments, the mass ratio of polyglycerol fatty acid esters, mono- and diglycerol fatty acid esters to sucrose fatty acid esters in the emulsifier is preferably 1:1 to 2:3 to 5, more preferably 1:1.5 to 1.8:3.5 to 4.5, and even more preferably 3:5:12.

[0039] In some embodiments, the gradient temperature control conditions are: 100W-150W for 1-2 minutes, then increased to 200W-250W for 2-3 minutes, and finally increased to 300W-400W for 2-3 minutes; the ultrasonic treatment is performed at a temperature of 0°C-10°C.

[0040] Some embodiments of the present invention also relate to a method for preparing the aforementioned microcapsule powder oil, comprising the following steps:

[0041] (1) Dissolve the wall material in water to obtain a stable aqueous solution; heat and melt the oil and emulsifier to obtain an oil solution;

[0042] (2) The aqueous solution is added to the oil solution and sheared and dispersed to obtain a crude emulsion;

[0043] (3) The crude emulsion is subjected to ultrasonic treatment under gradient temperature control to obtain a fine emulsion; the gradient temperature control conditions are: first, treat with 100W~150W for 0.5min~3min, then increase to 200W~250W for 1min~5min, and finally increase to 300W~400W for 1min~5min, and keep the emulsion temperature below 40℃ during the treatment process;

[0044] (4) The fine emulsion is homogenized under high pressure to obtain a homogenized emulsion;

[0045] (5) The homogenized emulsion is spray-dried to obtain the microcapsule powder oil.

[0046] In some embodiments, the water in step (1) is water at 60°C to 70°C, resulting in an aqueous phase solution at 60°C to 70°C. The heating and melting is performed at a temperature of 60°C to 65°C. In step (2), the aqueous phase solution is added to the oil phase solution by adding the aqueous phase solution preheated to 60°C to 70°C to the oil phase solution.

[0047] In some embodiments, the mass ratio of water to wall material in step (1) is 1-2:1.

[0048] In some embodiments, in step (2), the aqueous solution is added to the oil solution slowly while stirring at a speed of 500 rpm to 1000 rpm.

[0049] In some embodiments, the conditions for shear dispersion in step (2) include: a rotation speed of 12,000 rpm to 15,000 rpm, a time of 2 to 3 minutes, and repeated 2 to 4 times.

[0050] In some embodiments, the gradient temperature control conditions in step (3) are: 100W-150W for 1min-2min, then increased to 200W-250W for 2min-3min, and finally increased to 300W-400W for 2min-3min, and the ultrasonic treatment is carried out at a temperature of 0℃-10℃.

[0051] In some embodiments, the ultrasonic treatment in step (3) is performed by immersing an ultrasonic probe with a diameter of 10 mm to 15 mm into the crude emulsion at a depth of 1 cm to 2 cm.

[0052] In some embodiments, the conditions for high-pressure homogenization in step (4) include: pressure of 35MPa to 45MPa, and homogenization 2 to 4 times.

[0053] In some embodiments, the spray drying conditions in step (5) include: an inlet temperature of 160°C to 180°C, an outlet temperature of 75°C to 85°C, and a feed rate of 1.5 mL / min to 2.5 mL / min.

[0054] Some embodiments of the present invention also relate to the application of the microcapsule powder oil described herein as a special oil for rapid energy supply or in the preparation of foods for special medical purposes.

[0055] The present invention will be further described in detail below with reference to specific embodiments.

[0056] The raw materials used in the following embodiments are from the following sources:

[0057] Coconut diglyceride oil: Purchased from Guangdong Yueshan Special Medical Nutrition Technology Co., Ltd. The glycerides in this coconut diglyceride oil are mainly diglycerides, accounting for 80% of the total glycerides by mass; the fatty acids in this coconut diglyceride oil are mainly lauric acid, accounting for 42% of the total fatty acids by mass, C8-C9. 12 The content of fatty acids (including lauric acid) is 55% of the total fatty acids, and the content of unsaturated fatty acids is 11% of the total fatty acids.

[0058] Sodium caseinate: purchased from Aladdin, CAS number 9005-46-3.

[0059] Sodium octenyl succinate starch: purchased from Aladdin, CAS number 66829-29-6.

[0060] Maltodextrin: Purchased from Roquette Nutritional Foods Ltd., CAS No. 9050-36-6.

[0061] Whey protein: purchased from Aladdin, CAS number 84082-51-9.

[0062] Polyglycerol fatty acid esters: purchased from Henan Aonest Food Co., Ltd., CAS No. 67784-82-1.

[0063] Mono- and diglyceride fatty acid esters: purchased from Zhengzhou Yuxing Food Additives, CAS number 25339-99-0.

[0064] Sucrose fatty acid esters: purchased from Maclean's, CAS number 37318-31-3.

[0065] Resistant dextrin: purchased from Zhengzhou Yuxing Food Additives, CAS number 9004-53-9.

[0066] Chitosan: Purchased from Titan, CAS No. 9012-76-4.

[0067] Corn gliadin: purchased from Maclean's, CAS number 9010-66-6.

[0068] Soybean lecithin: purchased from Huaxia Houde, CAS number 8030-76-0.

[0069] Example 1

[0070] The microcapsule powder oil of diglycerides provided in this embodiment is prepared from the following raw materials (all percentages below are mass fractions): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0071] Its preparation method includes the following steps:

[0072] (1) Preparation of aqueous solution: Disperse the wall material in water at 65°C, wherein the mass ratio of water to wall material is approximately 1.5:1. Stir until fully dissolved and keep warm for 30 minutes to stabilize the system;

[0073] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0074] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0075] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0076] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0077] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0078] The method for determining the encapsulation loading of microcapsule powdered fat is as follows: According to the acid hydrolysis method in the National Food Safety Standard for Determination of Fat in Food (GB 5009.6-2016), the sample is hydrolyzed with hydrochloric acid, then extracted with anhydrous diethyl ether or petroleum ether, and the total content of free and bound fat is obtained by removing the solvent. The encapsulation loading is calculated according to formula (1).

[0079] Total oil content (%) = Mass of extract / Mass of sample × 100%……………Formula (1)

[0080] Method for determining surface oil content: According to the method in "Natural Fat Powder" (QB / T 4791-2015), 2g of sample was extracted twice with petroleum ether at room temperature, gently stirred, allowed to stand, and filtered. The filtrates were combined to obtain the surface oil. The surface oil content was calculated according to formula (2).

[0081] Surface oil content (%) = (total mass of oil in the bottle + total mass of oil dried to constant weight after extraction - constant weight receiving bottle) / sample mass × 100%................................................. Formula (2)

[0082] The method for determining the embedding rate is as follows: the embedding rate is the proportion of the embedded oil in the total oil, and the calculation is shown in formula (3).

[0083] Embedding rate (%) = (Total oil content - Surface oil content) / Total oil content × 100……Formula (3)

[0084] Reduced particle size determination method: The average particle size of different emulsions was determined using an LS-POP9 laser particle size analyzer. The refractive indices of the aqueous and oil phases were set to 1.33 and 1.46, respectively. Before measurement, all samples were diluted to an oil content of approximately 0.01% to avoid scattering effects. Pure water was used as the dispersion medium (refractive index 1.33), and the laser intensity was set to 85% ± 1%, with a feed pump speed of 2000 rpm / min. The sample was slowly added dropwise to the pure water in the measuring tank using a dropper. Once the instrument reached the measurement requirements, the addition was stopped, and the particle size was measured. The average value of three particle size measurements was recorded.

[0085] The powder properties of the diglyceride microcapsule powder oil in this embodiment were measured as follows: total oil content 80.4%, surface oil content 0.96%, encapsulation rate 98.8%, and particle size 1.2 μm.

[0086] Example 2

[0087] The microcapsule powder oil of diglyceride provided in this embodiment is prepared from the following raw materials (all percentages below are mass fractions): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:2.5), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0088] Its preparation method includes the following steps:

[0089] (1) Preparation of aqueous solution: Disperse the wall material in water at 65°C, wherein the mass ratio of water to wall material is approximately 1.5:1. Stir until fully dissolved and keep warm for 30 minutes to stabilize the system;

[0090] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0091] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0092] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0093] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0094] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0095] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0096] The powder properties of the diglyceride microcapsule powder oil in this embodiment were measured as follows: total oil content 77.6%, surface oil content 2.9%, encapsulation efficiency 96.3%, and particle size 1.8 μm.

[0097] Example 3

[0098] The microcapsule powder oil of diglycerides provided in this embodiment is prepared from the following raw materials (all percentages below are mass fractions): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3.5), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0099] Its preparation method includes the following steps:

[0100] (1) Preparation of aqueous solution: Disperse the wall material in water at 65°C, wherein the mass ratio of water to wall material is approximately 1.5:1. Stir until fully dissolved and keep warm for 30 minutes to stabilize the system;

[0101] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0102] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0103] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0104] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0105] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0106] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0107] The powder properties of the diglyceride microcapsule powder oil in this embodiment were measured as follows: total oil content 78.1%, surface oil content 2.3%, encapsulation efficiency 97.1%, and particle size 1.7 μm.

[0108] Comparative Example 1 (without ultrasound)

[0109] The difference between this comparative example and Example 1 is that ultrasonic treatment was not performed. The raw materials and other preparation steps are the same as in Example 1, as detailed below.

[0110] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0111] (1) Preparation of aqueous solution: Disperse the wall material in water at 65°C, wherein the mass ratio of water to wall material is approximately 1.5:1. Stir until fully dissolved and keep warm for 30 minutes to stabilize the system;

[0112] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0113] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0114] (3) High-pressure homogenization: The crude emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion;

[0115] (4) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0116] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0117] The powder properties of the diglyceride microcapsule powder of this comparative example were measured as follows: total oil content 65.4%, surface oil content 24.6%, encapsulation efficiency 62.4%, and particle size 28.1 μm.

[0118] Comparative Example 2 (with ultrasound but not gradient)

[0119] The difference between this comparative example and Example 1 is that the ultrasonic treatment was not performed in a gradient manner. The raw materials and other preparation steps are the same as in Example 1, as detailed below.

[0120] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0121] (1) Preparation of aqueous solution: Disperse the wall material in water at 65°C, wherein the mass ratio of water to wall material is approximately 1.5:1. Stir until fully dissolved and keep warm for 30 minutes to stabilize the system;

[0122] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0123] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0124] (3) Temperature-controlled ultrasound: Transfer the crude emulsion to a narrow-mouthed glass beaker and place the beaker in an ice-water bath. Select an ultrasound probe with a diameter of 12 mm, immerse it 1.5 cm below the surface of the crude emulsion, turn on the ultrasound machine, and use constant power ultrasound to treat the crude emulsion: constant power 350W ultrasound for 6.5 min; temperature is controlled throughout the process in an ice-water bath to ensure that the emulsion temperature is < 40℃.

[0125] (4) High pressure homogenization: The ultrasonic emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0126] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0127] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0128] The powder properties of the microcapsule powder of diglycerides in this comparative example were measured as follows: total oil content 68.8%, surface oil content 22.6%, encapsulation efficiency 67.1%, and particle size 18.1 μm.

[0129] Comparative Example 3 (with gradient ultrasound but not cryogenic)

[0130] The difference between this comparative example and Example 1 is that the low temperature was not controlled during the ultrasonic treatment. The raw materials and other preparation steps are the same as in Example 1, as detailed below.

[0131] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0132] (1) Preparation of aqueous solution: Disperse the wall material in water at 65°C, wherein the mass ratio of water to wall material is approximately 1.5:1. Stir until fully dissolved and keep warm for 30 minutes to stabilize the system;

[0133] Preparation of oil phase solution: Take 88% coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglyceride fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0134] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0135] (3) Gradient ultrasound: Transfer the crude emulsion to a narrow-mouthed glass beaker, select an ultrasonic probe with a diameter of 12 mm, immerse it 1.5 cm below the surface of the crude emulsion, turn on the ultrasonic instrument, and use gradient power ultrasound to treat the crude emulsion: first treat it with 120 W for 1.5 min to initially break up the oil droplets; then increase it to 220 W for 2.5 min to further refine it; finally increase it to 350 W for 2.5 min to obtain a fine emulsion with small particle size.

[0136] (4) High pressure homogenization: The ultrasonic emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0137] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0138] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0139] The powder properties of the microcapsule powder of diglycerides in this comparative example were measured as follows: total oil content 67.7%, surface oil content 23.4%, encapsulation efficiency 65.4%, and particle size 19.8 μm.

[0140] Comparative Example 4 (wall material ratio is 1:1:1:1)

[0141] The difference between this comparative example and Example 1 is that the proportion of the wall material is different. Other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0142] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:1), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0143] Its preparation method includes the following steps:

[0144] (1) Preparation of aqueous solution: Disperse the wall material in water at 65°C, wherein the mass ratio of water to wall material is approximately 1.5:1. Stir until fully dissolved and keep warm for 30 minutes to stabilize the system;

[0145] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0146] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0147] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0148] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0149] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0150] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0151] The powder properties of the diglyceride microcapsule powder in this comparative example were measured as follows: total oil content 75.8%, surface oil content 8.4%, encapsulation efficiency 88.9%, and particle size 4.3 μm.

[0152] Comparative Example 5 (Wall material lacking sodium octenyl succinate starch)

[0153] The difference between this comparative example and Example 1 is that the wall material lacks sodium octenyl succinate starch, while the other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0154] The microcapsule powder of diglycerides provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, maltodextrin and whey protein in a mass ratio of 1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0155] Its preparation method includes the following steps:

[0156] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0157] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0158] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0159] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0160] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0161] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0162] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0163] The powder properties of the diglyceride microcapsule powder of this comparative example were measured as follows: total oil content 74.9%, surface oil content 15.1%, encapsulation efficiency 79.8%, and particle size 11.1 μm.

[0164] Comparative Example 6 (Wall material lacking whey protein)

[0165] The difference between this comparative example and Example 1 is that the wall material lacks whey protein, while the other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0166] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch and maltodextrin in a mass ratio of 3:1:1), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0167] Its preparation method includes the following steps:

[0168] (1) Preparation of aqueous solution: Disperse the wall material in water at 65℃, where the mass ratio of water to wall material is about 1.5:1. Stir until fully dissolved and keep warm for 30 minutes to stabilize the system.

[0169] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0170] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0171] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0172] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0173] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0174] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0175] The powder properties of the microcapsule powder of diglycerides in this comparative example were measured as follows: total oil content 74.4%, surface oil content 17.9%, encapsulation efficiency 75.9%, and particle size 14.1 μm.

[0176] Comparative Example 7 (Wall material lacking sodium octenyl succinate starch and maltodextrin)

[0177] The difference between this comparative example and Example 1 is that the wall material lacks sodium octenyl succinate starch and maltodextrin, while the other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0178] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate and whey protein in a mass ratio of 1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0179] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0180] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0181] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0182] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0183] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0184] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0185] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0186] The powder properties of the diglyceride microcapsule powder of this comparative example were measured as follows: total oil content 71.1%, surface oil content 19.6%, encapsulation efficiency 72.4%, and particle size 17.4 μm.

[0187] Comparative Example 8 (Whey protein in the wall material was replaced with resistant dextrin)

[0188] The difference between this comparative example and Example 1 is that whey protein in the wall material is replaced with resistant dextrin, while other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0189] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and resistant dextrin in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0190] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0191] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0192] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0193] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0194] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0195] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0196] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0197] The powder properties of the diglyceride microcapsule powder of this comparative example were measured as follows: total oil content 75.4%, surface oil content 7.69%, encapsulation efficiency 89.8%, and particle size 3.8 μm.

[0198] Comparative Example 9 (Maltodextrin in the wall material was replaced with chitosan)

[0199] The difference between this comparative example and Example 1 is that maltodextrin in the wall material is replaced with chitosan, while other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0200] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, chitosan and whey protein in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0201] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0202] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0203] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0204] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0205] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0206] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0207] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0208] The powder properties of the microcapsule powder of diglycerides in this comparative example were measured as follows: total oil content 76.4%, surface oil content 9.09%, encapsulation efficiency 88.1%, and particle size 5.1 μm.

[0209] Comparative Example 10 (Sodium caseinate in the wall material is replaced with zein)

[0210] The difference between this comparative example and Example 1 is that sodium caseinate in the wall material is replaced with zein, while other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0211] The microcapsule powder of diglycerides provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of zein, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0212] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0213] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0214] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0215] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0216] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0217] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0218] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0219] The powder properties of the microcapsule powder of diglycerides in this comparative example were measured as follows: total oil content 74.7%, surface oil content 11.13%, encapsulation efficiency 85.1%, and particle size 7.8 μm.

[0220] Comparative Example 11 (Sodium caseinate in the wall material was replaced with zein, and whey protein was replaced with resistant dextrin)

[0221] The difference between this comparative example and Example 1 is that sodium caseinate is replaced with zein in the wall material, whey protein is replaced with resistant dextrin, and other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0222] The microcapsule powder of diglycerides provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of zein, sodium octenyl succinate starch, maltodextrin and resistant dextrin in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% mono- and diglycerol fatty acid esters and 1.2% sucrose fatty acid ester.

[0223] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0224] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0225] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0226] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0227] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0228] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0229] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0230] The powder properties of the diglyceride microcapsule powder of this comparative example were measured as follows: total oil content 75.7%, surface oil content 11.2%, encapsulation efficiency 85.2%, and particle size 8.2 μm.

[0231] Comparative Example 12 (Emulsifier only: sucrose fatty acid ester)

[0232] The difference between this comparative example and Example 1 is that the emulsifier is only sucrose fatty acid ester, while the other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0233] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, and 2% sucrose fatty acid ester.

[0234] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0235] Preparation of oil phase solution: Take coconut diglyceride oil, add sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0236] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0237] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0238] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0239] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0240] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0241] The powder properties of the diglyceride microcapsule powder of this comparative example were measured as follows: total oil content 74.7%, surface oil content 16.4%, encapsulation efficiency 78%, and particle size 12.4 μm.

[0242] Comparative Example 13 (The sucrose fatty acid ester in the emulsifier was changed to soybean lecithin)

[0243] The difference between this comparative example and Example 1 is that the sucrose fatty acid ester in the emulsifier is changed to soybean lecithin. Other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0244] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3), coconut diglyceride oil, polyglycerol fatty acid esters, mono- and diglycerol fatty acid esters and soybean lecithin.

[0245] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0246] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, mono- and diglycerol fatty acid ester and soybean lecithin, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0247] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0248] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0249] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0250] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0251] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0252] The powder properties of the microcapsule powder of diglycerides in this comparative example were measured as follows: total oil content 74.1%, surface oil content 11.4%, encapsulation efficiency 84.6%, and particle size 8.8 μm.

[0253] Comparative Example 14 (the mono- and diglycerides in the emulsifier were replaced with soybean lecithin)

[0254] The difference between this comparative example and Example 1 is that the mono- and diglyceride fatty acid esters in the emulsifier are changed to soybean lecithin. Other raw materials and preparation steps are the same as in Example 1, as detailed below.

[0255] The microcapsule powder of diglyceride provided in this comparative example is prepared from the following raw materials (all percentages below are by mass): 10% wall material (composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein in a mass ratio of 1:1:1:3), 88% coconut diglyceride oil, 0.3% polyglycerol fatty acid ester, 0.5% soybean lecithin and 1.2% sucrose fatty acid ester.

[0256] (1) Preparation of aqueous solution: The wall material is dispersed in water at 65 °C, wherein the mass ratio of water to wall material is approximately 1.5:1. The mixture is stirred until fully dissolved and kept at the temperature for 30 minutes to stabilize the system.

[0257] Preparation of oil phase solution: Take coconut diglyceride oil, add polyglycerol fatty acid ester, soybean lecithin and sucrose fatty acid ester, heat and melt in a water bath at 60℃~65℃, and stir gently with a glass rod.

[0258] (2) High-shear emulsification: The aqueous phase solution preheated to 65°C was slowly added to the oil phase at a stirring rate of 800 rpm. After pouring, high-shear dispersion was immediately performed at a speed of 13000 rpm for 2.5 minutes, and repeated 3 times to obtain a crude emulsion.

[0259] (3) Gradient-temperature controlled ultrasonic preparation of fine emulsion: The crude emulsion was transferred to a narrow-mouthed glass beaker and placed in an ice-water bath. A 12mm diameter ultrasonic probe was immersed 1.5cm below the surface of the crude emulsion. The ultrasonic instrument was turned on and the crude emulsion was ultrasonically treated using gradient power ultrasonic method: first, it was treated at 120W for 1.5min to initially break up the oil droplets; then it was treated at 220W for 2.5min to further refine the oil droplets; finally, it was treated at 350W for 2.5min to obtain a small-particle-size fine emulsion. The temperature was controlled in an ice-water bath throughout the process to ensure that the emulsion temperature was < 40℃.

[0260] (4) High pressure homogenization: The ultrasonic fine emulsion was homogenized three times under a pressure of 40 MPa to obtain a homogenized emulsion.

[0261] (5) Spray drying: The homogeneous emulsion is spray dried under the conditions of inlet temperature of 170°C, outlet temperature of 80°C and feed rate of 2mL / min to obtain the microcapsule powder oil.

[0262] The methods for determining the total oil content, surface oil content, encapsulation rate, and particle size of the microcapsule powder oil are the same as in Example 1.

[0263] The powder properties of the microcapsule powder of diglycerides in this comparative example were measured as follows: total oil content 75%, surface oil content 10.5%, encapsulation efficiency 86%, and particle size 5.2 μm.

[0264] The powder properties of the microcapsule powders of diglycerides prepared in the examples and comparative examples are summarized in Tables 1-3.

[0265] Table 1. Powder properties of microcapsule powders prepared with different wall materials

[0266]

[0267] Table 2. Powder properties of microcapsule powders prepared under different conditions

[0268]

[0269] Table 3. Powder properties of microcapsule powders prepared with different emulsifiers

[0270]

[0271] As shown in Tables 1-3, the wall material with a specific composition and ratio (sodium caseinate: sodium octenyl succinate starch: maltodextrin: whey protein = 1:1:1:3) and an emulsifier with a specific composition (polyglycerol fatty acid ester, mono- and diglycerol fatty acid esters and sucrose fatty acid ester), combined with ultrasonic gradient low-temperature treatment, can synergistically produce microcapsule powder oil with the highest oil content (80.4%) and encapsulation rate (98.8%), and the smallest particle size (1.2 μm).

[0272] Compared to Example 1, which did not undergo ultrasonic treatment, Comparative Example 1 showed significantly lower oil content and encapsulation efficiency in the resulting microcapsule powder compared to Example 1, while exhibiting significantly larger particle size. Comparative Examples 2 and 3 underwent ultrasonic treatment but without gradient or low-temperature control. Consequently, their microcapsule powder oil content, encapsulation efficiency, and particle size were not significantly improved compared to Comparative Example 1, remaining significantly worse than Example 1. This may be because high-intensity ultrasound generates localized high temperatures and free radicals, easily leading to the oxidation and deterioration of diglycerides and damaging the emulsifying activity of protein-based wall materials (e.g., causing whey protein denaturation), thus reducing the encapsulation efficiency. This invention employs gradient ultrasonic treatment with low-temperature control throughout, ensuring the emulsion temperature remains below 40°C during processing. This effectively inhibits oil oxidation, improves the emulsifying activity of the wall material, overcomes the problems of oil oxidation and wall material failure caused by ultrasonic treatment, and improves the oil content and encapsulation efficiency of the microcapsule powder oil.

[0273] Comparative Examples 4-7, compared to Example 1, changing the proportion of the wall material or reducing one or two wall materials significantly reduced the oil content and encapsulation efficiency of the resulting microcapsule powder oil, while significantly increasing the particle size. Comparative Examples 8-11, compared to Example 1, replacing one or two wall materials with other types significantly reduced the oil content and encapsulation efficiency of the resulting microcapsule powder oil. Comparative Examples 12-14, compared to Example 1, changing the type of emulsifier significantly reduced the oil content and encapsulation efficiency of the resulting microcapsule powder oil, while significantly increasing the particle size.

[0274] The above results demonstrate that the specific composition and ratio of the wall material (sodium caseinate: sodium octenyl succinate starch: maltodextrin: whey protein = 1:1:1:3) and the specific composition of the emulsifier, combined with low-temperature gradient ultrasonic treatment, have a synergistic effect. This significantly improves the oil content and encapsulation efficiency of the obtained diglyceride microcapsule powder oil, and reduces the particle size. The smaller particle size of the microcapsule powder oil increases the specific surface area of ​​the reconstituted emulsion, allowing for rapid dispersion and release of oil in water. The microcapsule powder oil of this invention can meet both the long-term storage requirements for oxidative stability in special medical foods and the urgent needs of patients for rapid energy supply.

[0275] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A microcapsule powdered oil, characterized in that, By mass percentage, the raw material components of the microcapsule powder oil include: 82%–92% oil, 5%–15% wall material, and 1%–3% emulsifier, wherein the mass content of diglycerides in the oil is not less than 80%; The wall material is composed of sodium caseinate, sodium octenyl succinate starch, maltodextrin and whey protein, and the whey protein in the wall material accounts for ≥50% by mass. The emulsifier is a compound of polyglycerol fatty acid esters, mono- and diglycerol fatty acid esters and sucrose fatty acid esters; The preparation method of the microcapsule powder oil of the diglyceride includes a gradient temperature controlled ultrasound step: the crude emulsion made of the oil, wall material and emulsifier is ultrasonically treated under gradient temperature controlled conditions, the gradient temperature controlled conditions are: first treated at 100W to 150W for 0.5min to 3min, then increased to 200W to 250W for 1min to 5min, and finally increased to 300W to 400W for 1min to 5min, and the emulsion temperature is kept below 40℃ during the treatment.

2. The microcapsule powder oil according to claim 1, characterized in that, The raw material components of the microcapsule powder oil include: 85%–90% oil, 8%–12% wall material, and 1%–3% emulsifier.

3. The microcapsule powder oil according to claim 1, characterized in that, The whey protein content in the wall material is 50% to 54%, more preferably 50% to 52%, and even more preferably 50%.

4. The microcapsule powder oil according to claim 1, characterized in that, The mass ratio of sodium caseinate, sodium octenyl succinate starch, maltodextrin, and whey protein in the wall material is 0.5–1.5:0.5–1.5:0.5–1.5:2–4, preferably 1:0.8–1.2:0.8–1.2:2.5–3.5, more preferably 1:0.9–1.1:0.9–1.1:2.5–3.5, even more preferably 1:0.9–1.1:0.9–1.1:2.9–3.2, even more preferably 1:1:1:2.5–3.5, even more preferably 1:1:1:2.9–3.2, and even more preferably 1:1:1:

3.

5. The microcapsule powder oil according to claim 1, characterized in that, The oil contains 80%-85% by mass of diglycerides; preferably, the oil contains 50%-60% by mass of fatty acids with a carbon chain length of 8-12 and 9%-14% by mass of unsaturated fatty acids; preferably, the oil contains 40%-45% by mass of lauric acid; preferably, the oil is coconut diglyceride oil or walnut diglyceride oil.

6. The microcapsule powder oil according to claim 1, characterized in that, The mass ratio of polyglycerol fatty acid esters, mono- and diglycerol fatty acid esters to sucrose fatty acid esters in the emulsifier is 1:1 to 2:3 to 5, more preferably 1:1.5 to 1.8:3.5 to 4.5, and even more preferably 3:5:

12.

7. The microcapsule powder oil according to any one of claims 1-6, characterized in that, The gradient temperature control conditions are as follows: 100W-150W for 1-2 minutes, then increased to 200W-250W for 2-3 minutes, and finally increased to 300W-400W for 2-3 minutes; the ultrasonic treatment is carried out at a temperature of 0℃-10℃.

8. A method for preparing microcapsule powdered oil according to any one of claims 1 to 7, characterized in that, Includes the following steps: (1) Dissolve the wall material in water to obtain a stable aqueous solution; heat and melt the oil and emulsifier to obtain an oil solution; (2) The aqueous solution is added to the oil solution and sheared and dispersed to obtain a crude emulsion; (3) The crude emulsion is subjected to ultrasonic treatment under gradient temperature control to obtain a fine emulsion; the gradient temperature control conditions are: first, treat with 100W~150W for 0.5min~3min, then increase to 200W~250W for 1min~5min, and finally increase to 300W~400W for 1min~5min, and keep the emulsion temperature below 40℃ during the treatment process; (4) The fine emulsion is homogenized under high pressure to obtain a homogenized emulsion; (5) The homogenized emulsion is spray-dried to obtain the microcapsule powder oil.

9. The method for preparing microcapsule powdered oil according to claim 8, characterized in that, The water in step (1) is water at 60℃~70℃, and an aqueous phase solution at 60℃~70℃ is obtained. The heating and melting is carried out at a temperature of 60℃~65℃. In step (2), the aqueous phase solution is added to the oil phase solution by adding the aqueous phase solution preheated to 60℃~70℃ to the oil phase solution. And / or, the mass ratio of water to wall material in step (1) is 1-2:1; And / or, in step (2), the aqueous solution is added to the oil solution by slowly adding the aqueous solution to the oil solution at a stirring rate of 500 rpm to 1000 rpm; And / or, the conditions for shear dispersion in step (2) include: a rotation speed of 12,000 rpm to 15,000 rpm, a time of 2 to 3 minutes, and repeated 2 to 4 times; And / or, the gradient temperature control conditions in step (3) are: 100W~150W for 1min~2min, then increase to 200W~250W for 2min~3min, and finally increase to 300W~400W for 2min~3min, and the ultrasonic treatment is carried out at a temperature of 0℃~10℃; And / or, the ultrasonic treatment in step (3) is performed by immersing an ultrasonic probe with a diameter of 10 mm to 15 mm into the crude emulsion at a depth of 1 cm to 2 cm. And / or, the conditions for high-pressure homogenization in step (4) include: pressure of 35MPa to 45MPa, homogenization 2 to 4 times; And / or, the conditions for spray drying in step (5) include: an air inlet temperature of 160℃~180℃, an air outlet temperature of 75℃~85℃, and a feed rate of 1.5mL / min~2.5mL / min.

10. The use of the microcapsule powder oil according to any one of claims 1 to 7 as a special oil for rapid energy supply or in the preparation of foods for special medical purposes.

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