Food-grade ultrafine emulsion with improved nutrient stability and preparation method and application thereof

Abstract

This invention provides a food-grade ultramicroemulsion for improving nutrient stability, its preparation method, and its application, relating to the field of food technology. The food-grade ultramicroemulsion of this invention, by weight, comprises the following components: 5-20 parts polyol, 5-30 parts oil, 0.1-2 parts primary emulsifier, 0.01-0.5 parts co-emulsifier, and 60-90 parts water; the primary emulsifier is selected from at least one of polyglycerol fatty acid esters and mono- and diglycerol fatty acid esters; the co-emulsifier is selected from at least one of sucrose fatty acid esters, diacetyl tartaric acid mono- and diglycerides, phospholipids, and citrate fatty acid glycerides. The components are mixed and sheared under mild conditions of 50-65°C, resulting in an emulsion with a narrow particle size distribution, high stability, and high retention rate of fat-soluble nutrients.

Description

Technical Field

[0001] This invention belongs to the field of food technology, specifically relating to food-grade ultra-microemulsions for improving nutrient stability, their preparation methods, and applications. Background Technology

[0002] Fat-soluble nutrients play a crucial role in human health, possessing functions such as antioxidation, maintaining vision, promoting bone health, and supporting the immune system. However, due to their poor water solubility and stability, they are difficult to use directly in food products.

[0003] To overcome the aforementioned problems with fat-soluble nutrients, most current processing methods employ microencapsulation technology. However, microencapsulation technology also has certain limitations: 1. Microencapsulation often requires a large amount of wall material, resulting in low nutrient carrying capacity, high cost, and complex preparation process; 2. During microencapsulation, nutrients may not be completely encapsulated within the microcapsule, leaving unencapsulated nutrients directly exposed to the external environment, making them susceptible to oxidation and decomposition reactions caused by light, heat, and oxygen, thus reducing nutrient stability and effectiveness; 3. The microcapsule wall materials used in food typically have weak shear strength and high-temperature resistance, easily leading to nutrient leakage into the external environment and reducing their stability. Traditional emulsification technologies use high-pressure homogenization and ultrasonic emulsification to prepare emulsions for encapsulating fat-soluble nutrients, but the high temperature and pressure during emulsification can lead to nutrient loss. For example, Chinese invention patent CN115177001A describes an emulsified composition containing the following components: low fat-soluble substances, phospholipids, vitamin E, solid fats and liquid oils. Even with high-speed shearing and high-pressure homogenization at 6000-12000 rpm for encapsulation, it is still impossible to effectively encapsulate the low fat-soluble substances and other components. The resulting emulsified composition has low stability and leads to the loss of effective components during long-term storage.

[0004] D-phase emulsification is a low-energy emulsification technology with broad application prospects due to its high load-bearing capacity, high stability, and low energy consumption. This technology prepares emulsions through phase behavior regulation and dynamic dilution. A dynamic intermediate phase (D-phase) is formed by the self-assembly of a mixture of polyols, surfactants, and water. This D-phase has a layered liquid crystal structure, which can significantly reduce interfacial tension. The hydrophobic regions of the layered liquid crystal can efficiently encapsulate oil phase molecules. After inducing the formation of the O (oil) / D phase, the O / D liquid crystal structure undergoes a phase transition through gradual dilution with water, forming a new O (oil) / W (water) system. This reduces the tendency for droplet aggregation and promotes the formation of nano-sized droplets. Although D-phase emulsification technology is commonly used in the cosmetics industry, most cosmetic ingredients are not suitable for food. Furthermore, cosmetic preparation requires a high proportion of emulsifiers, which can damage the gastrointestinal mucosa in food, while a low proportion leads to decreased nutrient stability. Therefore, conventional cosmetic emulsification technologies are not suitable for food. In the food industry, there are few reports on the preparation of high-loading, high-stability ultrafine O / W emulsions using D-phase emulsification technology.

[0005] Chinese invention patent CN117837745A discloses a heat-stable, high-oil-loading emulsion resistant to acids, alkalis, and salts, its preparation method, and its applications. This emulsion is composed of oils, a primary emulsifier, a co-emulsifier, a stabilizer, an antioxidant, and deionized water in a specific ratio. The preparation process involves dispersion, dissolution, stirring, shearing, and high-pressure homogenization to form the emulsion. Its oil loading capacity is over 40%. The resulting emulsion remains stable within a pH range of 3-9 and in solutions containing sodium, potassium, calcium, and magnesium ions, exhibiting excellent physical and chemical stability. Even after accelerated aging at 57°C for 20 days, it remains homogeneous and stable, with a peroxide value below 0.13 g / 100 g. However, the co-emulsifiers in this invention are propylene glycol and glycerol, used in high proportions; furthermore, the excessively high proportions of sucrose fatty acid esters and polyoxyethylene sorbitan fatty acid esters used as co-emulsifiers limit its application in food.

[0006] In most emulsification technology studies, a large amount of primary emulsifiers and co-emulsifiers are used to improve the stability and retention rate of the encapsulated components. This leads to high content of excipients and low encapsulation efficiency and dispersibility of components such as oils and nutrients. Reducing the amount of encapsulation materials such as primary emulsifiers and co-emulsifiers inevitably results in a decrease in the product's shear resistance and high-temperature stability. In existing studies, the total amount of primary emulsifiers and co-emulsifiers used in food emulsification processes accounts for approximately 10%-30%, which is still a relatively high proportion. Therefore, researching a more efficient and gentle method to encapsulate fat-soluble nutrients with lower amounts of primary emulsifiers and co-emulsifiers to address the problems of poor nutrient dispersibility and stability is an urgent problem to be solved in emulsification processes for emulsion preparation. Summary of the Invention

[0007] This invention addresses the problems existing in the prior art by providing a food-grade ultramicroemulsion that enhances nutrient stability, its preparation method, and its application.

[0008] Specifically, this invention employs D-phase emulsification technology to prepare an O / W (oil-in-water) food-grade ultramicroemulsion system. This system can encapsulate a large amount of fat-soluble nutrients, improving nutrient retention, and exhibits good stability and uniformity without stratification. This invention utilizes D-phase emulsification technology to precisely control the ternary ratio of emulsifier / polyol / oil phase, achieving D-phase-O / D-phase-O / W phase transitions, thus preparing food-grade ultramicroemulsions with narrow particle size distributions without the need for high-pressure homogenization.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0010] On the one hand, the present invention provides a food-grade ultra-microemulsion for improving the stability of nutrients, which, by weight, is composed of the following components: 5-20 parts of polyol, 5-30 parts of oil, 0.1-2 parts of main emulsifier, 0.01-0.5 parts of co-emulsifier, and 60-90 parts of water; The primary emulsifier is selected from at least one of polyglycerol fatty acid esters and mono- and diglycerol fatty acid esters; The emulsifier is selected from at least one of sucrose fatty acid esters, diacetyl tartaric acid mono- and diglycerides, phospholipids, and citrate fatty acid glycerides.

[0011] Preferably, the food-grade microemulsion is composed of the following components by weight: 8-15 parts polyol, 5-20 parts oil, 0.3-1 part main emulsifier, 0.1-0.3 parts co-emulsifier, and 68.7-81.05 parts water.

[0012] More preferably, the food-grade microemulsion is composed of the following components by weight: 8-15 parts of polyol, 5-20 parts of oil, 0.3-1 part of primary emulsifier, 0.1-0.3 parts of co-emulsifier, and 68.7-79.6 parts of water.

[0013] More preferably, the food-grade microemulsion is composed of the following components by weight: 8-10 parts of polyol, 8-15 parts of oil, 0.8-1 parts of primary emulsifier, 0.15-0.3 parts of co-emulsifier, and 68.7-81.05 parts of water.

[0014] More preferably, the food-grade microemulsion is composed of the following components by weight: 8-10 parts of polyol, 8-15 parts of oil, 0.8-1 parts of primary emulsifier, 0.15-0.3 parts of co-emulsifier, and 74.35-81.05 parts of water.

[0015] Most preferably, the food-grade microemulsion is composed of the following components by weight: 10 parts polyol, 20 parts oil, 1 part main emulsifier, 0.3 parts co-emulsifier, and 68.7 parts water.

[0016] Preferably, the polyol is selected from at least one of glycerol, xylitol, maltitol, isomaltitol, sorbitol, and lactitol.

[0017] In this invention, the polyol can be a commercially available liquid or a polyol solution prepared by adding water to a powdered polyol; the mass concentration of the polyol solution is 50%-99.9%.

[0018] More preferably, the polyol is selected from one of glycerol, xylitol, maltitol, isomaltitol, sorbitol, and lactitol; or the polyol is selected from at least two of glycerol, xylitol, maltitol, isomaltitol, sorbitol, and lactitol.

[0019] Preferably, the oil is selected from at least one of DHA (docosahexaenoic acid) algal oil, astaxanthin oil, microalgae oil (commonly known as EPA (eicosapentaenoic acid) algal oil), lutein ester, high oleic sunflower seed oil, maple seed oil, γ-linolenic acid oil, flaxseed oil, walnut oil, *Sapindus mukorossi* oil, olive oil, diglycerides, and medium-chain triglycerides.

[0020] More preferably, the oil is selected from at least one of DHA algal oil, astaxanthin oil, micrococcus oil, and lutein ester.

[0021] Preferably, the co-emulsifier is selected from one of sucrose fatty acid esters, diacetyl tartaric acid mono- and diglycerides, phospholipids, and citrate fatty acid glycerides; or the co-emulsifier is selected from at least two of sucrose fatty acid esters, diacetyl tartaric acid mono- and diglycerides, phospholipids, and citrate fatty acid glycerides.

[0022] On the other hand, the present invention provides a method for preparing the above-mentioned food-grade ultramicroemulsion, comprising the steps of: (1) After the polyol, the main emulsifier, and the co-emulsifier are mixed at 50-65℃, phase D of component is obtained; (2) The oil and D phase are mixed and sheared to obtain the O / D phase; (3) Add water at 40-60℃ to the O / D phase and stir to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized to obtain food-grade ultramicroemulsion.

[0023] Preferably, in step (1), the mixing temperature is 55-60°C.

[0024] More preferably, in step (1), the mixing temperature is 60°C.

[0025] Preferably, in step (2), the mixing temperature is 50-65°C.

[0026] More preferably, in step (2), the mixing temperature is 55-60°C.

[0027] More preferably, in step (2), the mixing temperature is 60°C.

[0028] Preferably, in step (2), the mixing is carried out at a rotation speed of 200-500 rpm.

[0029] More preferably, in step (2), the mixing is carried out at a rotational speed of 300 rpm.

[0030] Preferably, in step (2), the mixing time is 10-30 min.

[0031] More preferably, in step (2), the mixing time is 30 minutes.

[0032] Preferably, in step (2), the shearing speed is 1000-3000 rpm.

[0033] More preferably, in step (2), the shearing speed is 3000 rpm.

[0034] Preferably, in step (2), the shearing process takes 2-8 minutes.

[0035] More preferably, in step (2), the shearing process takes 6 minutes.

[0036] Preferably, in step (3), the temperature of the water is 50°C.

[0037] Preferably, in step (3), the stirring speed of the O / D phase is 200-500 rpm. More preferably, in step (3), the stirring speed of the O / D phase is 300 rpm.

[0038] Preferably, in step (3), the stirring time is 10-30 minutes. More preferably, in step (3), the stirring time is 30 minutes.

[0039] Preferably, in step (4), the sterilization conditions are: 70-121℃ for 10-30 min, or 130-150℃ for 2-30 s.

[0040] More preferably, in step (4), the sterilization conditions are: maintaining at 121°C for 10 minutes.

[0041] Finally, this invention provides the application of the above-mentioned food-grade ultramicroemulsion in food preparation.

[0042] Compared with the prior art, the present invention has the following beneficial effects: 1. The food-grade ultra-micro emulsion of the present invention uses raw materials with specific ratios and components, and the components work together to form a stable emulsion system with good properties. The particle size Dv50 of the food-grade ultra-micro emulsion reaches 200-600nm, which is small, has high bioavailability, and has a narrow particle size distribution, thus having good stability and not separating or floating oil during long-term storage.

[0043] 2. This invention utilizes D-phase emulsification technology to prepare O / W food-grade ultramicroemulsions, which can carry a large amount of fat-soluble nutrients. The emulsification process is mild, which improves the retention rate of fat-soluble nutrients and results in a narrow particle size distribution.

[0044] 3. The food-grade ultra-micro emulsion of this invention has a simple formula, does not contain thickeners or other ingredients, and has an emulsifier content of less than 10‰, making the product easier to digest and absorb, and safer and gentler.

[0045] 4. The preparation method of the present invention is simple, and emulsification can be achieved without high-pressure homogenization. The emulsion reaches the nanoscale, and the resulting food-grade ultramicro emulsion not only helps to improve the stability of nutrients, but also the emulsification process has low equipment requirements and low energy consumption, which is conducive to practical production applications. Detailed Implementation

[0046] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0047] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the invention, both endpoints of each numerical range and any value between the two endpoints may be selected. 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.

[0048] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention are obtained through conventional commercial channels. Information on the main raw materials used in the specific embodiments of the present invention is shown in Table 1. Products from different manufacturers do not have a significant impact on the efficacy.

[0049] In a specific embodiment of the invention, the maltitol used is a 75% maltitol solution, and the xylitol used is a 99% xylitol solution. In the following specific embodiments, 1 part maltitol means 1 part maltitol solution, and 1 part xylitol means 1 xylitol solution.

[0050] Table 1 Raw Material Purchase Information

[0051] Example 1 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 10 parts glycerol, 20 parts DHA algal oil, 1 part polyglycerol fatty acid ester, 0.3 parts phospholipids, and 68.7 parts water.

[0052] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 10 parts of glycerol, 1 part of polyglycerol fatty acid ester and 0.3 parts of phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0053] Example 2 A food-grade microemulsion for improving nutrient stability, by weight, consists of the following components: 15 parts maltitol (75% by mass), 5 parts DHA algal oil, 0.3 parts mono- and diglycerides of fatty acids, 0.1 parts diacetyl tartaric acid mono- and diglycerides, and 79.6 parts water.

[0054] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 15 parts of maltitol, 0.3 parts of mono- and diglycerides of fatty acids and 0.1 parts of diacetyl tartaric acid mono- and diglycerides, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 5 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0055] Example 3 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 10 parts xylitol (99% by mass), 8 parts astaxanthin oil, 0.8 parts polyglycerol fatty acid ester, 0.15 parts diacetyl tartaric acid mono- and diglycerides, and 81.05 parts water.

[0056] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 10 parts xylitol, 0.8 parts polyglycerol fatty acid ester and 0.15 parts diacetyl tartaric acid mono- and diglycerides, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 8 parts of astaxanthin oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0057] Example 4 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 8 parts xylitol (99% by mass), 15 parts astaxanthin oil, 1 part mono- and diglyceride fatty acid esters, 0.15 parts sucrose fatty acid esters, and 74.35 parts water.

[0058] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 8 parts xylitol, 1 part mono- and diglyceride fatty acid esters and 0.15 parts sucrose fatty acid esters, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 15 parts of astaxanthin oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0059] Example 5 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 8 parts isomaltitol, 20 parts microalgae oil, 1 part polyglycerol fatty acid ester, 0.3 parts citric acid fatty acid glyceride, and 68.7 parts water.

[0060] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 8 parts of isomaltitol, 1 part of polyglycerol fatty acid ester and 0.3 parts of citrate fatty acid glyceride, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of pseudomicroalgae oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0061] Example 6 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 15 parts sorbitol, 5 parts lutein ester, 0.3 parts polyglycerol fatty acid ester, 0.1 parts phospholipid, and 81.05 parts water.

[0062] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 15 parts of sorbitol, 0.3 parts of polyglycerol fatty acid ester and 0.1 parts of phospholipid, and heat to 50°C to obtain a uniformly dispersed mixed component D phase; (2) At 50℃ and 300rpm, 5 parts of lutein ester were slowly added to phase D and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain phase O / D. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 70°C for 30 minutes; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0063] Example 7 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 5 parts lactitol, 5 parts DHA algal oil, 0.1 parts polyglycerol fatty acid ester, 0.01 parts phospholipid, and 60 parts water.

[0064] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 5 parts lactitol, 0.1 parts polyglycerol fatty acid ester and 0.01 parts phospholipid, and heat to 55°C to obtain a uniformly dispersed mixed component D phase; (2) At 55℃ and 200rpm, 5 parts of DHA algal oil were slowly added to the D phase and stirred for 20min to obtain a viscoelastic mixture. Then, the mixture was sheared at 1000rpm for 8min to obtain the O / D phase. (3) Add 60°C warm water to the O / D phase at 200 rpm and stir for 10 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized under the following conditions: 130°C for 30 seconds; then cooled to below 35°C and stored to obtain a food-grade ultra-microemulsion.

[0065] Example 8 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 20 parts glycerol, 30 parts DHA algal oil, 2 parts polyglycerol fatty acid ester, 0.5 parts phospholipid, and 90 parts water.

[0066] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 20 parts of glycerol, 2 parts of polyglycerol fatty acid ester and 0.5 parts of phospholipid, and heat to 65°C to obtain a uniformly dispersed mixed component D phase; (2) At 65℃ and 500rpm, 30 parts of DHA algal oil were slowly added to the D phase and stirred for 10min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 2min to obtain the O / D phase. (3) Add 40°C warm water to the O / D phase at 500 rpm and stir for 10 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized under the following conditions: 150°C for 2 seconds; then cooled to below 35°C and stored to obtain a food-grade ultra-microemulsion.

[0067] Example 9 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 5 parts glycerol, 5 parts xylitol (99% by mass), 20 parts DHA algal oil, 1 part polyglycerol fatty acid ester, 0.1 parts sucrose fatty acid ester, 0.2 parts phospholipids, and 68.7 parts water.

[0068] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 5 parts glycerol, 5 parts xylitol, 1 part polyglycerol fatty acid ester, 0.1 part sucrose fatty acid ester and 0.2 parts phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0069] Example 10 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 3 parts maltitol (75% by mass), 3 parts isomaltitol, 4 parts sorbitol, 20 parts DHA algal oil, 1 part polyglycerol fatty acid ester, 0.2 parts diacetyl tartaric acid mono- and diglycerides, 0.1 parts phospholipids, and 68.7 parts water.

[0070] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 3 parts maltitol, 3 parts isomaltitol, 4 parts sorbitol, 1 part polyglycerol fatty acid ester, 0.2 parts diacetyl tartaric acid mono- and diglycerides, and 0.1 parts phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0071] Example 11 A food-grade microemulsion for improving nutrient stability, comprising, by weight, the following components: 10 parts glycerol, 20 parts DHA algal oil, 0.5 parts polyglycerol fatty acid ester, 0.5 parts mono- and diglycerol fatty acid ester, 0.3 parts phospholipid, and 68.7 parts water.

[0072] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 10 parts of glycerol, 0.5 parts of polyglycerol fatty acid ester, 0.5 parts of mono- and diglycerol fatty acid ester and 0.3 parts of phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0073] Comparative Example 1 Unlike Example 1, the phospholipid component was omitted, and the water content was 69 parts.

[0074] The food-grade microemulsion is composed of the following components by weight: 10 parts glycerol, 20 parts DHA algal oil, 1 part polyglycerol fatty acid ester, and 69 parts water.

[0075] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 10 parts of glycerol and 1 part of polyglycerol fatty acid ester, heat to 60°C, and obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0076] Comparative Example 2 Unlike Example 1, the amounts of glycerin and water used are different.

[0077] The food-grade microemulsion is composed of the following components by weight: 1 part glycerol, 20 parts DHA algal oil, 1 part polyglycerol fatty acid ester, 0.3 parts phospholipid, and 77.7 parts water.

[0078] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 1 part glycerol, 1 part polyglycerol fatty acid ester and 0.3 part phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0079] Comparative Example 3 Unlike Example 1, the amounts of glycerin and water used are different.

[0080] The food-grade microemulsion, by weight, consists of the following components: 25 parts glycerol, 20 parts DHA algal oil, 1 part polyglycerol fatty acid ester, 0.3 parts phospholipid, and 53.7 parts water.

[0081] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 25 parts of glycerol, 1 part of polyglycerol fatty acid ester and 0.3 parts of phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0082] Comparative Example 4 Unlike Example 1, the amounts of the main emulsifier polyglycerol fatty acid ester and water are different.

[0083] The food-grade microemulsion, by weight, consists of the following components: 10 parts glycerol, 20 parts DHA algal oil, 3 parts polyglycerol fatty acid ester, 0.3 parts phospholipid, and 66.7 parts water.

[0084] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 10 parts glycerol, 3 parts polyglycerol fatty acid ester and 0.3 parts phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0085] Comparative Example 5 Unlike Example 1, this comparative example was prepared using a conventional method.

[0086] The preparation method of food-grade microemulsion is as follows: (1) Mix 10 parts glycerol, 1 part polyglycerol fatty acid ester, and 0.3 parts phospholipid, then add 68.7 parts water, heat and stir at 60°C until the emulsifier is completely dispersed to form an aqueous phase; (2) 20 parts of DHA algal oil were added to the aqueous phase at 8000 rpm and sheared for 10 min to obtain O / W primary emulsion; (3) Homogenize the O / W primary emulsion at 25 MPa once to obtain an emulsion; (4) The emulsion is filled and sterilized under the following conditions: 121°C for 10 minutes; then cooled to below 35°C and stored to obtain a food-grade ultra-micro emulsion.

[0087] Comparative Example 6 Unlike Example 1, the amounts of the main emulsifier polyglycerol fatty acid ester and water are different.

[0088] The food-grade microemulsion is composed of the following components by weight: 10 parts glycerol, 20 parts DHA algal oil, 0.05 parts polyglycerol fatty acid ester, 0.3 parts phospholipid, and 69.65 parts water.

[0089] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 10 parts of glycerol, 0.05 parts of polyglycerol fatty acid ester and 0.3 parts of phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; (2) At 60℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 50°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0090] Comparative Example 7 Unlike Example 1, the ratio of primary emulsifier to co-emulsifier is different.

[0091] The food-grade microemulsion, by weight, consists of the following components: 10 parts glycerol, 20 parts DHA algal oil, 0.3 parts polyglycerol fatty acid ester, 1 part phospholipid, and 68.7 parts water.

[0092] The preparation method of the above-mentioned food-grade ultramicroemulsion is as follows: (1) Mix 10 parts glycerol, 0.3 parts polyglycerol fatty acid ester and 1 part phospholipid, and heat to 60°C to obtain a uniformly dispersed mixed component D phase; Steps (2)-(4) are the same as in Example 1.

[0093] Comparative Example 8 According to the ingredients and dosages described in Example 1 of Chinese Invention Patent CN117837745A, the stabilizers vitamin E polydiethanol succinate and sorbitol are omitted; at the same time, the high-pressure homogenization step is omitted.

[0094] (1) Weigh 340g of nonionized water, add 8.5g of sucrose fatty acid ester and 1.5g of polyoxyethylene (20) sorbitan monooleate, stir until evenly dispersed, heat to 75℃, and after fully swelling, add 50g of propylene glycol and 76g of glycerol, dissolve, add 8g of octaglycerol monooleate, stir evenly, this is the aqueous phase.

[0095] (2) Weigh 160g sunflower seed oil, 150g soybean oil and 150g corn oil, add 4g rosemary extract and 1.0g mono- and diglyceride fatty acid esters, and dissolve by sonication at 60°C. This is the oil phase.

[0096] (3) The oil phase is slowly added to the aqueous phase. During this process, the temperature is kept at 55°C and the stirring speed is kept at 400 rpm to form the primary emulsion.

[0097] (4) Weigh 3g of ascorbic acid and 8g of sodium ascorbate and dissolve them in 30g of nonionized water. Then add them to the above primary emulsion and stir at 300rpm. Add water to make up the emulsion mass to 1000g. Shear the emulsion at 5500rpm for 2 minutes and sterilize it at 121℃ for 10 minutes before storing.

[0098] Comparative Example 9 The difference from Example 1 is that the polyglycerol fatty acid ester is replaced with sodium octenyl succinate starch, and the phospholipid is replaced with polysorbate-80. Everything else is the same as in Example 1.

[0099] Comparative Example 10 The difference from Example 1 is that the phospholipids are replaced with polyoxyethylene sorbitan fatty acid esters. Everything else is the same as in Example 1.

[0100] Comparative Example 11 The difference from Example 1 is that the polyglycerol fatty acid ester is replaced with polyglycerol ricinoleate. Everything else is the same as in Example 1.

[0101] Comparative Example 12 Unlike Example 1, the preparation method of the food-grade microemulsion is different.

[0102] The preparation method of food-grade microemulsion is as follows: (1) Mix 10 parts of glycerol, 1 part of polyglycerol fatty acid ester and 0.3 parts of phospholipid, and heat to 70°C to obtain a uniformly dispersed mixed component D phase; (2) At 70℃ and 300rpm, 20 parts of DHA algal oil were slowly added to the D phase and stirred for 30min to obtain a viscoelastic mixture. Then, the mixture was sheared at 3000rpm for 6min to obtain the O / D phase. (3) Add 70°C warm water to the O / D phase at 300 rpm and stir for 30 min to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized. The sterilization conditions are 121°C for 10 min; then cooled to below 35°C and stored to obtain food-grade ultra-microemulsion.

[0103] Effect Test 1: Particle Size Detection Particle size testing method: Refer to GB / T 19077-2024.

[0104] The particle size distribution results of the emulsions prepared in each embodiment and comparative example are shown in Table 2. Among them, the emulsions prepared in Comparative Examples 2 and 6-9 exhibited significant oil floating before filling, indicating instability and heterogeneity; therefore, particle size was not measured. The O / D phases prepared in Comparative Examples 3 and 4 had excessively high viscosity, making it difficult to transform into a homogeneous O / W phase after the addition of the aqueous phase. This resulted in a viscous paste-like consistency and a water layer, possibly due to excessive emulsifier and polyol addition. Excessive emulsifier may excessively aggregate around the oil phase or form a bicontinuous phase, hindering the relative movement between oil phase molecules and significantly increasing the viscosity of the O / D phase. The high viscosity and cohesive force make it difficult for the aqueous phase to effectively penetrate into the O / D phase to achieve phase transformation. Furthermore, the uneven distribution of the emulsifier in the high-viscosity O / D phase fails to effectively reduce the surface tension at the oil-water interface, thus hindering the phase transformation process from the O / D phase to the O / W phase.

[0105] Therefore, no further testing will be conducted on the above comparative examples.

[0106] Table 2 Results of Emulsion Particle Size Detection

[0107] Results analysis: Comparative Example 2 may have resulted in oil floating due to insufficient polyol addition. When too little polyol is added, the solubilizing ability is weakened, the emulsifier and oil phase cannot mix well, and it is difficult to form an O / D phase with good structure and stability. When the aqueous phase is added subsequently, the emulsifier cannot effectively form a stable interfacial film at the oil-water interface, resulting in oil droplets not being evenly dispersed in the aqueous phase, thus causing oil floating.

[0108] Comparative Examples 6 and 9 may have resulted in insufficient addition of the main emulsifier and changes in its composition, leading to the inability to form a stable interfacial film at the oil-water interface and the occurrence of oil floating. In Comparative Example 9, the emulsifying ability in the system was weak when the amount of octenyl succinic starch added was 1 part.

[0109] In Comparative Example 7, the change in the ratio of primary emulsifier and co-emulsifier resulted in insufficient primary emulsifier, leading to an inadequate number of molecules that could be effectively adsorbed at the interface, insufficient reduction in interfacial tension, and a thin and incomplete interfacial film. Excessive co-emulsifier disrupted the interfacial arrangement of the primary emulsifier and even altered the phase behavior and liquid crystal structure of the system, causing an imbalance in the D-phase gel network structure, which lost its ability to fix oil droplets, resulting in floating oil.

[0110] Comparative Example 8, referring to the technical solution of CN117837745A, omitted the auxiliary stabilizers vitamin E polydiethanol succinate and sorbitol, as well as the high-pressure homogenization step. Due to the lack of auxiliary stabilizers, the interfacial film strength was insufficient, and oil droplets were prone to coalescence. At the same time, after the high-pressure homogenization technology was replaced by conventional shearing, it could only provide limited mechanical energy and could not break the droplets into a uniform and smaller state like high-pressure homogenization, resulting in the phenomenon of oil-water stratification.

[0111] As shown in Table 2, the particle size results of Examples 1-11 are generally below 600 nm (Dv50) and nanometer-level (Dv90), with particle sizes lower than those of Comparative Examples 1, 5, 10-12. The O / W system prepared using the D-phase emulsification technique exhibits a significantly reduced particle size, which is beneficial for human digestion and absorption. Simultaneously, the narrower particle size distribution further contributes to system stability. Compared to Comparative Examples 1, 5, and 10-12, the differences in Dv50 and Dv90 between the examples are smaller, and the particle size distribution is narrower.

[0112] In Comparative Example 1, omitting phospholipids as a co-emulsifier prevents the synergistic effect of phospholipids and polyglycerol fatty acid esters in the polyol aqueous solution from being utilized. However, the embodiments of this invention employ specific types of co-emulsifiers and primary emulsifiers, which synergistically significantly reduce the thermodynamic barrier to emulsion formation and substantially lower the interfacial tension of the system. This significantly reduces the Gibbs free energy change required for emulsion formation, transforming emulsion formation from thermodynamically non-spontaneous to kinetically metastable, thereby producing an emulsion with a narrower particle size distribution.

[0113] The increased particle size and wider distribution observed in Comparative Examples 10 and 11 may be due to the antagonistic effect of polyoxyethylene sorbitan fatty acid ester, polyglycerol fatty acid ester, and polyglycerol ricinoleate on the phospholipids after component substitution, leading to a decrease in the overall system stability. At the oil-water interface, polyoxyethylene sorbitan fatty acid ester and polyglycerol ricinoleate may compete with polyglycerol fatty acid ester and phospholipids for adsorption sites, affecting their normal structural regulation and emulsifying effects. Furthermore, the addition of these components may disrupt the formation of the ordered structure of the D phase, thus affecting the final emulsion particle size and uniformity. This demonstrates that the choice of component types has a significant impact on the technical effect.

[0114] In Comparative Example 12, the D-phase gel network structure was destroyed due to excessively high emulsification temperature, which weakened the fixation effect on oil droplets, making the droplets more prone to aggregation and increasing the particle size.

[0115] Compared with Comparative Example 5, the D-phase emulsification technology of the present invention is simpler, consumes less energy, has lower equipment requirements, and produces food-grade ultrafine emulsions with smaller particle sizes, which is more conducive to practical production applications.

[0116] Effect Test 2: Stability Test The thermal stability of the emulsion samples from Examples 1-11, Comparative Examples 1, 5, 10-12 was investigated.

[0117] The samples were poured into 25 mL high-temperature resistant PP bottles, sterilized, and then stored in the dark at 37°C. After 1 and 3 months of accelerated storage, the stratification and floating oil conditions of the system were observed. The results are shown in Table 3.

[0118] Table 3. Thermal stability results of the emulsion system

[0119] As shown in Table 3, the food-grade ultrafine O / W emulsion system prepared by the D-phase emulsification technology of this invention is stable, showing no changes after 3 months of accelerated processing. Comparative Examples 1 and 10-12, however, exhibited oil floating and demulsification. This may be because the interfacial film formed by using polyglycerol fatty acid esters alone in Comparative Example 1 is relatively brittle and lacks flexibility; in Comparative Examples 10 and 11, after component replacement, the interfacial film formed by the emulsion is rigid, inelastic, and easily ruptured. When used with polyglycerol fatty acid esters or phospholipids, the antagonistic effect leads to a more fragile overall interfacial structure, making it difficult to completely prevent collisions and aggregation between oil droplets. With time or changes in external conditions, oil droplets easily break through the interfacial film and coalesce, leading to demulsification. In Comparative Example 12, the excessively high emulsification temperature destroyed the D-phase gel structure, preventing the oil droplets from being completely and uniformly fixed. The resulting emulsion particles were larger and less uniform. As time progressed, the Ostwald ripening rate increased, intensifying spontaneous oil separation and demulsification. The stratification phenomenon observed in Comparative Example 5 may be due to the poor uniformity and large size of the emulsion particles. As time progresses, the Ostwald ripening phenomenon intensifies, and under the influence of gravity, larger droplets are more likely to settle, while smaller droplets may float. The lighter droplets encapsulating the oil gradually float and aggregate together. At this point, the interfacial film is not completely ruptured, thus resulting in stratification.

[0120] Effect Experiment 3: Retention Rate Test of Fat-Soluble Nutrients The retention rate of fat-soluble nutrients in the accelerated emulsion samples of Examples 1-11, Comparative Examples 1, 5, and Comparative Examples 10-12 was determined under the accelerated conditions of 37°C and protection from light.

[0121] Methods for determining the retention rate of fat-soluble nutrients: The retention rates of DHA, astaxanthin, EPA (fatty acid component in Micrococcus pseudochlorella oil), and lutein esters were determined according to GB 5009.168-2016 Method 1, GB / T 30893-2024, GB 5009.168-2016 Method 1, and QB / T 5941-2023, respectively.

[0122] The retention rates of fat-soluble nutrients are shown in Table 4.

[0123] Table 4 Results of fat-soluble nutrient retention rates in emulsions

[0124] The “-” in Table 4 indicates that the food-grade ultra-microemulsion system showed significant instability in subsequent accelerated experiments, therefore nutrient retention rate testing was not conducted.

[0125] As shown in Table 4, in the initial stage, no obvious layering or floating oil phenomenon was observed in the food-grade ultra-microemulsion systems of Examples 1-11 and Comparative Examples 1, 5, and 10-12. Examples 1-11 showed high nutrient retention rates with virtually no loss after sterilization. However, Comparative Examples 1, 5, and 10-12 experienced significant DHA loss after sterilization. This may be due to two reasons: firstly, the interfacial film formed in Comparative Example 1 was relatively fragile, allowing external oxygen to easily penetrate and react with DHA, accelerating its oxidation and degradation, thus reducing the DHA content in the emulsion; secondly, the uneven particle size distribution in Comparative Example 5, with droplets of different sizes having different specific surface areas and heat transfer characteristics, could lead to droplet aggregation at high temperatures, increasing the contact between oxygen and DHA and accelerating the oxidation reaction. Comparative Examples 10-12 exhibited both of these reasons. The results show that the fat-soluble nutrients in Examples 1-11 were relatively stable during the shelf life, which may be related to the relatively mild D-phase emulsification process, the selection of ingredients, and the good particle size distribution of the system.

[0126] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A food-grade ultramicroemulsion for enhancing stability of nutrients, characterized by, Based on parts by weight, it consists of the following components: 5-20 parts polyol, 5-30 parts oil, 0.1-2 parts main emulsifier, 0.01-0.5 parts co-emulsifier, and 60-90 parts water; The primary emulsifier is selected from at least one of polyglycerol fatty acid esters and mono- and diglycerol fatty acid esters; The co-emulsifier is selected from at least one of sucrose fatty acid esters, diacetyl tartaric acid mono- and diglycerides, phospholipids, and citrate fatty acid glycerides. The polyol is selected from at least one of glycerol, xylitol, maltitol, isomaltitol, sorbitol, and lactitol; The preparation method of food-grade microemulsion includes the following steps: (1) After the polyol, the main emulsifier, and the co-emulsifier are mixed at 50-65℃, phase D of component is obtained; (2) The oil and D phase are mixed and sheared to obtain the O / D phase; (3) Add water at 40-60℃ to the O / D phase and stir to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized to obtain food-grade ultramicroemulsion.

2. The food-grade ultra-microemulsion according to claim 1, characterized in that, Based on parts by weight, it consists of the following components: 8-15 parts polyol, 5-20 parts oil, 0.3-1 part main emulsifier, 0.1-0.3 parts co-emulsifier, and 68.7-81.05 parts water.

3. The food-grade ultra-microemulsion according to claim 2, characterized in that, Based on parts by weight, it consists of the following components: 8-15 parts polyol, 5-20 parts oil, 0.3-1 part main emulsifier, 0.1-0.3 parts co-emulsifier, and 68.7-79.6 parts water.

4. The food-grade ultra-microemulsion of claim 2, wherein, Based on parts by weight, it consists of the following components: 8-10 parts polyol, 8-15 parts oil, 0.8-1 part main emulsifier, 0.15-0.3 parts co-emulsifier, and 68.7-81.05 parts water.

5. The food-grade ultra-microemulsion according to claim 4, characterized in that, Based on parts by weight, it consists of the following components: 8-10 parts polyol, 8-15 parts oil, 0.8-1 part main emulsifier, 0.15-0.3 parts co-emulsifier, and 74.35-81.05 parts water.

6. The food-grade ultra-microemulsion of claim 3, wherein, The product is composed of the following components by weight: 10 parts polyol, 20 parts oil, 1 part main emulsifier, 0.3 parts co-emulsifier, and 68.7 parts water.

7. The food-grade ultra-microemulsion of claim 1, wherein, The oil is selected from at least one of the following: DHA algal oil, astaxanthin oil, microchlorella oil, lutein ester, high oleic sunflower seed oil, maple seed oil, γ-linolenic acid oil, flaxseed oil, walnut oil, *Sapindus mukorossi* oil, olive oil, diglycerides, and medium-chain triglycerides.

8. Process for the preparation of a food-grade ultramicroemulsion according to any one of claims 1 to 7, characterized in that, Includes the following steps: (1) After the polyol, main emulsifier, and co-emulsifier are mixed at 50-65℃, component D phase is obtained; (2) The oil and D phase are mixed and sheared to obtain the O / D phase; (3) Add water at 40-60℃ to the O / D phase and stir to obtain O / W nanoemulsion; (4) The O / W nanoemulsion is filled and sterilized to obtain food-grade ultramicroemulsion.

9. The production method according to claim 8, characterized by, In step (1), the mixing temperature is 55-60℃; And / or, in step (2), the mixing temperature is 50-65°C, the mixing is carried out at a speed of 200-500 rpm, and the mixing time is 10-30 min; And / or, in step (2), the shearing speed is 1000-3000 rpm and the shearing time is 2-8 min; And / or, in step (3), the temperature of the water is 50°C; And / or, in step (3), the stirring speed of the O / D phase is 200-500 rpm, and the stirring time is 10-30 min; And / or, in step (4), the sterilization conditions are: 70-121℃ for 10-30 min, or 130-150℃ for 2-30 s.

10. The application of the food-grade microemulsion according to any one of claims 1-7 in food preparation.

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