Emulsion composition, method for producing same, and food, milk substitute, pharmaceutical, cosmetic and personal care product containing emulsion composition

Abstract

The present invention relates to an oil-in-water emulsion composition which contains solid particles, water, an oil and fat, and at least one component selected from the group consisting of alkali metal salts and polysaccharides, wherein the solid particles are present at the interface between the water and the oil and fat, the solid particles contain gramineous plant-derived proteins, and the content of the gramineous plant-derived proteins relative to the total mass of the solid particles is 50-100 mass %.

Description

Emulsion composition, its manufacturing method, and foods, milk substitutes, pharmaceuticals, cosmetics and personal care products containing the emulsion composition

[0001] The present invention relates to an emulsion composition, a method for producing the same, and foods, milk substitutes, pharmaceuticals, cosmetics, and personal care products containing the emulsion composition. This application claims priority to Japanese Patent Application No. 2024-121098, filed on July 26, 2024, the contents of which are incorporated herein by reference.

[0002] Surfactants have been used for emulsification in the food industry. However, because surfactant-based emulsification is thermodynamically unstable, it has been necessary to reduce the oil droplet size of oil-in-water emulsions (O / W emulsions) to the submicron level in order to ensure long-term stability and stability during sterilization processes at high temperatures.

[0003] In recent years, the food industry has seen increasing demand for features such as an appetite-stimulating appearance, flavor (stimulating the senses of taste and smell), texture, and health-conscious ingredients. Therefore, there is a need for the development of oil-in-water emulsions with emulsion sizes and structures different from those of conventional emulsified compositions using surfactants. Meanwhile, with the increasing number of food allergy sufferers, restrictions on the use of allergenic substances are sometimes imposed, drawing increasing attention to the food ingredients used. Food allergies are highly dangerous, potentially causing severe symptoms such as itching and inflammation of the skin and anaphylactic shock, which can lead to death. Therefore, for food applications, there is a need for oil-in-water emulsions in which the allergenic substance in the food ingredient used is replaced with a different food ingredient, depending on the allergenicity of the consumer. For example, to address milk allergies, it is necessary to avoid milk-derived proteins as food ingredients, particularly the highly allergenic casein and whey protein β-lactoglobulin. It is also known that soybean-derived proteins can be allergenic. In addition, proteins derived from peanuts and nuts such as walnuts and almonds are also known to be allergenic substances. In providing emulsion compositions, it is known that emulsions can be stabilized using fine particles such as colloids, as a method other than emulsification using surfactants. Emulsions stabilized by the adsorption of fine particles to a liquid-liquid interface such as oil-water are called "fine particle-stabilized emulsions" or "Pickering emulsions." In recent years, research into fine particle-stabilized emulsions (Pickering emulsions) has been actively conducted. For example, Patent Document 1 discloses an oil-in-water Pickering emulsion containing solid particles such as rice-derived protein, a nonionic amphiphilic substance such as a sucrose fatty acid ester or a polyglycerin fatty acid ester, an oil phase component, and an aqueous phase component, and discloses that such oil-in-water Pickering emulsions have excellent heat resistance and emulsion stability. However, the heat resistance of the oil-in-water Pickering emulsion described in Patent Document 1 still needs improvement.Patent Documents 2 to 5 disclose oil-in-water emulsion compositions having microparticles containing a protein and an anionic polysaccharide, and methods for producing the same. However, the proteins described in Patent Documents 2 to 5 are mainly whey proteins, and there is still room for improvement in terms of excluding allergenic substances. Furthermore, there is also room for improvement in terms of reducing the environmental load to prevent global warming and in terms of replacing animal-derived proteins such as whey proteins.

[0004] International Publication No. WO 2019 / 240239 JP 2022-074064 A JP 2022-042778 A International Publication No. WO 2019 / 087666 International Publication No. WO 2022 / 025132

[0005] In fields where the oil-in-water emulsion composition of the present invention is applied, such as the food industry, the oil-in-water emulsion composition may be exposed to relatively high temperatures due to processing, sterilization, or the like. Therefore, a first object of the present invention is to provide an oil-in-water emulsion composition with higher heat resistance. A second object of the present invention is to provide an oil-in-water emulsion composition that has both high heat resistance and temperature-lowering resistance. Furthermore, in fields where the oil-in-water emulsion composition of the present invention is applied, such as the food industry, there is a demand for products that do not contain components that may be allergenic to consumers. Therefore, a third object of the present invention is to provide an oil-in-water emulsion composition that can serve as a substitute for edible materials containing specific allergens, depending on the allergens of the consumer. A fourth object of the present invention is to provide an animal-derived food substitute that does not contain animal-derived ingredients, thereby contributing to reducing the environmental impact, a social issue.

[0006] The present inventors conducted extensive research to solve the above-mentioned problems and found that the above-mentioned problems can be solved by using specific solid particles, alkali metal salts, and / or polysaccharides. Specifically, the present invention has the following aspects: (1) An oil-in-water emulsion composition comprising solid particles, water, an oil, and at least one component selected from the group consisting of an alkali metal salt and a polysaccharide, wherein the solid particles are present at the interface between the water and the oil, the solid particles contain a grass family plant-derived protein, and the content of the grass family plant-derived protein relative to the total mass of the solid particles is 50 to 100 mass%. (2) The oil-in-water emulsion composition according to (1), wherein the solid particles have a volume-based average particle size of 0.01 μm or more and 50 μm or less. (3) The oil-in-water emulsion composition according to (1) or (2), wherein the mass ratio of the content of the polysaccharide to the content of the solid particles is 0.5 or less. (4) The oil-in-water emulsion composition according to any one of (1) to (3), wherein the mass ratio of the content of the polysaccharide to the content of the fat or oil is 10 or less. (5) The oil-in-water emulsion composition according to any one of (1) to (4), wherein the composition contains the alkali metal salt and has a pH of more than 7. (6) The oil-in-water emulsion composition according to (5), wherein the pH is more than 7 and not more than 8.8. (7) The oil-in-water emulsion composition according to any one of (1) to (6), wherein the alkali metal salt is an alkali metal salt of an inorganic acid. (8) The oil-in-water emulsion composition according to any one of (1) to (7), wherein the alkali metal salt is a sodium salt or potassium salt of carbonate or bicarbonate. (9) The oil-in-water emulsion composition according to any one of (1) to (8), wherein the grass plant-derived protein is a rice-derived protein. (10) The oil-in-water emulsion composition according to any one of (1) to (9), wherein the content of the alkali metal salt is less than 100 mM relative to the total volume of the oil-in-water emulsion composition. (11) The oil-in-water emulsion composition according to any one of (1) to (10), comprising the polysaccharide, wherein the polysaccharide is an ionic polysaccharide. (12) The oil-in-water emulsion composition according to any one of (1) to (11), wherein the polysaccharide is at least one acidic polysaccharide selected from the group consisting of carrageenan, pectin, gum arabic, xanthan gum, gellan gum, agar, and tragacanth gum.(13) An oil-in-water emulsion composition comprising solid particles, water, and an oil and fat, and having a thermal history of being heated at a temperature exceeding 95°C, wherein the solid particles comprise a protein derived from a grass family plant, and the oil and fat form oil droplets having a diameter of 0.2 μm to 1 mm. (14) A method for producing an oil-in-water emulsion composition comprising solid particles, water, an oil and fat, and an alkali metal salt, the method comprising the steps of: mixing an aqueous phase component containing an alkali metal salt with solid particles to form a first mixture and stirring the first mixture; mixing the mixture obtained in the first step with an oil phase component to form a second mixture and stirring the second mixture; (15) The production method according to (14), wherein the pH of the aqueous phase component containing the alkali metal salt exceeds 7. (16) The production method according to (14) or (15), further comprising a step of micronizing the solid particles. (17) The production method according to any one of (14) to (16), further comprising a step of heating at a temperature exceeding 95°C. (18) A method for producing an oil-in-water emulsion composition comprising solid particles, water, oils and polysaccharides, comprising the steps of mixing an aqueous phase component with solid particles to form a first mixture and stirring the first mixture, mixing the mixture obtained in the first step with an oil phase component to form a second mixture and stirring the second mixture, and adding a polysaccharide to an emulsion obtained by stirring the second mixture, wherein the solid particles comprise a protein derived from a grass plant. (19) The production method according to (18), further comprising a step of micronizing the solid particles. (20) The production method according to (18) or (19), further comprising a step of heating at a temperature exceeding 95°C. (21) A food product comprising the oil-in-water emulsion composition according to any one of (1) to (13). (22) A milk substitute comprising the oil-in-water emulsion composition according to any one of (1) to (13). (23) A pharmaceutical comprising the oil-in-water emulsion composition according to any one of (1) to (13). (24) A cosmetic comprising the oil-in-water emulsion composition according to any one of (1) to (13). (25) A personal care product comprising the oil-in-water emulsion composition according to any one of (1) to (13).

[0007] The present invention may further have the following aspects. (26) An oil-in-water emulsion composition comprising solid particles, water, oils and fats, and at least one component selected from the group consisting of alkali metal salts and polysaccharides, wherein the solid particles are composed of a protein derived from a grass plant. (27) The oil-in-water emulsion composition according to (26), which comprises the alkali metal salt and has a pH of greater than 7. (28) The oil-in-water emulsion composition according to (26) or (27), which has a pH of greater than 7 but not greater than 8.8. (29) The oil-in-water emulsion composition according to any one of (26) to (28), wherein the alkali metal salt is a sodium or potassium salt of carbonate or bicarbonate. (30) The oil-in-water emulsion composition according to any one of (26) to (29), wherein the solid particles are composed of a protein derived from rice. (31) The oil-in-water emulsion composition according to any one of (26) to (30), wherein the content of the alkali metal salt is less than 100 mM relative to the total volume of the oil-in-water emulsion composition. (32) The oil-in-water emulsion composition according to any one of (26) to (31), wherein the polysaccharide is an ionic polysaccharide. (33) The oil-in-water emulsion composition according to any one of (26) to (32), wherein the solid particles are composed of rice-derived proteins. (34) The oil-in-water emulsion composition according to any one of (26) to (33), wherein the polysaccharide is at least one acidic polysaccharide selected from the group consisting of carrageenan, pectin, gum arabic, xanthan gum, gellan gum, agar, and tragacanth gum. (35) The oil-in-water emulsion composition according to any one of (26) to (34), wherein the ratio of the content of the polysaccharide to the content of the solid particles in the oil-in-water emulsion composition is not more than 10. (36) An oil-in-water emulsion composition comprising solid particles, water, and an oil and fat, and having a thermal history of being heated at a temperature exceeding 95°C, wherein the solid particles are composed of a protein derived from a grass family plant, and the oil and fat form oil droplets, the diameter of which is maintained at 0.2 μm or more and 1 mm or less.(37) A method for producing an oil-in-water emulsion composition comprising solid particles, water, oils and an alkali metal salt, the method comprising the steps of mixing an aqueous phase component containing an alkali metal salt with solid particles to prepare a first mixture and stirring the first mixture, and mixing the mixture obtained in the first step with an oil phase component to prepare a second mixture and stirring the second mixture, wherein the solid particles are composed of a protein derived from a grass plant. (38) The method according to (37), wherein the pH of the aqueous phase component containing the alkali metal salt is adjusted to exceed 7. (39) The method according to (37) or (38), further comprising a step of micronizing the solid particles. (40) The method according to any one of (37) to (39), further comprising a step of heating at a temperature exceeding 95°C. (41) A method for producing an oil-in-water emulsion composition comprising solid particles, water, oils and polysaccharides, the method comprising the steps of mixing an aqueous phase component with solid particles to form a first mixture and stirring the first mixture, mixing the mixture obtained in the first step with an oil phase component to form a second mixture and stirring the second mixture, and adding a polysaccharide to the emulsion obtained by stirring the second mixture, wherein the solid particles are composed of a protein derived from a grass plant. (42) The method according to (41), further comprising a step of micronizing the solid particles. (43) The method according to (41) or (42), further comprising a step of heating at a temperature exceeding 95°C. (44) A food product comprising the oil-in-water emulsion composition according to any one of (26) to (36). (45) A milk substitute comprising the oil-in-water emulsion composition according to any one of (26) to (36). (46) A pharmaceutical comprising the oil-in-water emulsion composition according to any one of (26) to (36). (47) A cosmetic comprising the oil-in-water emulsion composition according to any one of (26) to (36). (48) A personal care product comprising the oil-in-water emulsion composition according to any one of (26) to (36).

[0008] According to the present invention, it is possible to provide an oil-in-water emulsion composition that does not undergo separation of the oil phase or the formation of aggregates of oil droplets and solid particles, even when subjected to high-temperature treatment such as retort treatment (121°C for 30 minutes). According to the present invention, it is possible to provide an oil-in-water emulsion composition that has both high heat resistance and temperature-drop resistance. According to the present invention, it is possible to provide an oil-in-water emulsion composition that can serve as a substitute for edible materials containing specific allergens, depending on the allergenicity of the consumer, because it uses a protein derived from a grass family plant that is unlikely to be an allergen. Furthermore, it is possible to provide an animal-derived food substitute that does not contain animal-derived ingredients, which contributes to reducing the environmental burden, a social issue.

[0009] 1 is a graph showing the particle size distribution of oil droplets of oil-in-water emulsion composition A1 in Example 1-1 before and after heating. FIG. 2 is a graph showing the particle size distribution of oil droplets of oil-in-water emulsion composition A2 in Example 2-1 before and after heating. FIG. 3 is a graph showing the particle size distribution of oil droplets of oil-in-water emulsion composition A3 in Example 3-1 before and after heating. FIG. 4 is a graph showing the particle size distribution of oil droplets of oil-in-water emulsion composition A4 in Comparative Example 1-1 before and after heating. FIG. 5 is a graph showing the particle size distribution of oil droplets of oil-in-water emulsion composition A5 in Comparative Example 2-1 before and after heating. FIG. 6 is a microscopic image (drawing substitute photograph) of a sample of Example 1-1 (oil-in-water emulsion composition A1) before heat treatment at 121°C, observed at room temperature. FIG. 7 is a microscopic image (drawing substitute photograph) of a sample of Example 1-1 (oil-in-water emulsion composition A1) after heat treatment at 121°C, observed at room temperature. 1 is a graph showing the particle size distribution of oil droplets before and after mixing heat-sterilized Example 2-1 (oil-in-water emulsion composition A2) with demineralized water in a beverage production example. 2 is a graph showing the particle size distribution of oil droplets before and after mixing heat-sterilized Example 2-1 (oil-in-water emulsion composition A2) with black tea in a beverage production example. 3 is a graph showing the particle size distribution of oil droplets before and after mixing heat-sterilized Example 2-1 (oil-in-water emulsion composition A2) with coffee in a beverage production example. 4 is a polarized microscope photograph of Preparation Example 3-2 (oil-in-water emulsion composition B1) at room temperature (drawing substitute photograph). 5 is a polarized microscope photograph of Preparation Example 3-2 (oil-in-water emulsion composition B1) at the extinction position at room temperature (drawing substitute photograph). 6 is a graph showing the particle size distribution of oil droplets of oil-in-water emulsion composition B1-1 in Example 1-2 before and after heat treatment at 121°C. 1 is a graph showing the particle size distribution of oil droplets in oil-in-water emulsion composition B1-2 in Example 2-2 before and after heat treatment at 121°C. 2 is a graph showing the particle size distribution of oil droplets in oil-in-water emulsion composition B1-3 in Example 3-2 before and after heat treatment at 121°C. 3 is a graph showing the particle size distribution of oil droplets in oil-in-water emulsion composition B1-5 in Example 5-2 before and after heat treatment at 121°C. 4 is a graph showing the particle size distribution of oil droplets in oil-in-water emulsion composition B1-6 in Example 6-2 before and after heat treatment at 121°C.1 is a graph showing the particle size distribution of oil droplets in oil-in-water emulsion composition B1-7 in Comparative Example 1-2, before and after heat treatment at 121°C. 2 is a graph showing the particle size distribution of oil droplets in oil-in-water emulsion composition B2-1 in Comparative Example 2-2, before and after heat treatment at 121°C. 3 is a graph showing the particle size distribution of oil droplets in oil-in-water emulsion composition B1-8 in Comparative Example 3-2, before and after heat treatment at 121°C. 4 is a graph showing the particle size distribution of oil droplets in oil-in-water emulsion composition B1-9 in Comparative Example 4-2, before and after heat treatment at 121°C.

[0010] Embodiments of the present invention are described in detail below. The following description of the constituent elements is an example (e.g., a representative example or a preferred example) of an embodiment of the present invention, and the present invention is not limited to these details as long as it does not depart from the gist of the invention. <<Oil-in-Water Emulsion Composition>> One embodiment of the present invention is an oil-in-water emulsion composition comprising solid particles, water, oils and fats, and at least one component selected from the group consisting of alkali metal salts and polysaccharides, wherein the solid particles are present at the interface between the water and the oil, the solid particles comprise a grass plant-derived protein, and the content of the grass plant-derived protein relative to the total mass of the solid particles is 50 to 100 mass%. Another embodiment of the present invention is an oil-in-water emulsion composition comprising solid particles, water, oils and fats, and at least one component selected from the group consisting of alkali metal salts and polysaccharides, wherein the solid particles are composed of a grass plant-derived protein. As used herein, the term "oil-in-water emulsion composition" refers to not only so-called O / W oil-in-water emulsion compositions in which the continuous phase is water, but also multiphase emulsions such as W / O / W oil-in-water emulsion compositions. As used herein, "solid particles" refers to particles that are insoluble in media applicable to oil-in-water emulsion compositions, such as water and oils and fats. "Insoluble" refers to particles that are dispersible in a solvent (medium) without dissolving. That is, particles whose particle diameter (major axis size, etc.) in a solvent (medium) can be identified. For example, particle diameters in water can be measured at 20 to 25°C. Furthermore, from the viewpoint of maintaining the emulsion structure and emulsion stability of the present invention, it is preferable that the solid particles do not melt during the process of producing / processing the oil-in-water emulsion composition. From this viewpoint, the melting point of the solid particles under atmospheric pressure is usually 20°C or higher, preferably 65°C or higher, more preferably 80°C or higher, even more preferably 100°C or higher, particularly preferably 120°C or higher, especially preferably 150°C or higher, and most preferably 160°C or higher. By using solid particles having a melting point in this range, the solid particles can be maintained in a solid state adsorbed at the water-oil interface even during high-temperature heat treatment, thereby making it possible to obtain an oil-in-water emulsion composition having high heat resistance.

[0011] <First Aspect> In this specification, the oil-in-water emulsion composition described above is referred to as the first aspect when it comprises solid particles, water, an oil, and an alkali metal salt, the solid particles being present at the interface between the water and the oil, the solid particles containing a grass family plant-derived protein, the content of the grass family plant-derived protein relative to the total mass of the solid particles being 50 to 100% by mass, and the pH is greater than 7.

[0012] (Solid Particles) As described above, in one embodiment, the solid particles are particles that are insoluble in a medium applicable to the oil-in-water emulsion composition, such as water and oils and fats. Therefore, they do not dissolve in the aqueous phase component and the oil phase component used in the oil-in-water emulsion composition. Even after adding the solid particles to the aqueous phase component and / or the oil phase component, the aqueous phase and / or the oil phase can be stirred. The solid particles may be one type of solid particle, or a combination of two or more types of solid particles selected arbitrarily. Furthermore, the solid particles before being dispersed in a medium may be in the form of a powder, a paste, or a pellet. At least a portion of the solid particles may be present at the interface between the water and the oil, or all of the solid particles may be present at the interface between the water and the oil.

[0013] In one embodiment, the solid particles comprise a protein derived from a grass plant. Here, the term "grass plant" is not particularly limited and refers to plants belonging to the family Poaceae. That is, the solid particles of the present invention may be composed of a protein derived from any plant classified as a grass plant. Examples of grass plants include rice (including rice seeds, brown rice, polished rice, and rice), wild rice, maize (corn), wheat, barley, oats, oats, rye, sorghum, barnyard millet, foxtail millet, bamboo, bamboo grass, and sugarcane. Rice (including rice seeds, brown rice, polished rice, and rice) and maize (corn) are preferred, and rice (including rice seeds, brown rice, polished rice, and rice) is more preferred. In particular, in the case of rice among the grasses, examples include rice seeds, rice, unhulled rice, brown rice, polished rice (white rice, etc.), rice bran, etc., with rice seeds, rice, brown rice, and polished rice being preferred, rice, brown rice, and polished rice being more preferred, and polished rice being even more preferred. Examples of the grass family include rice plants (rice), Zoysia spp. (Zizania latifolia), Triticum spp. (wheat), Hordeum spp. (barley), Avena spp. (oats), Secale spp. (sorghum, sorghum), Panicum spp. (millet), Echinochloa spp. (barnyard millet), Setaria spp. (foxtail millet), Zea mays (corn), Saccharum spp. (sugarcane), Phyllostachys pubescens (Philadelphia bamboo, Phyllostachys moso, Phyllostachys chinensis, Phyllostachys saccharum), Sasa spp., Miscanthus spp., Job's tears spp., Phragmites spp., Zoysia spp., and Bamboo spp. However, the present invention is not limited to these examples. Among these, plants of the genus Oryza, Sorghum, Millet, Barnyardgrass, Setaria, Maize, Saccharum, and Miscanthus are preferred, with Oryza and Maize being more preferred, and Oryza being even more preferred. Since the above-mentioned grass-derived proteins are plant proteins, the use of these proteins makes it possible to provide foods that comply with religious restrictions and vegetarian foods. Furthermore, by appropriately selecting and using these grass-derived proteins, it becomes possible to provide foods that comply with food restrictions due to food allergies (e.g., milk allergies, soybean allergies), i.e., food ingredients, such as those restricted by certain food ingredients.Furthermore, by using proteins derived from specific grasses as described above, it is possible to provide emulsion compositions and foods with superior flavor. By appropriately selecting and using proteins derived from the above-described preferred grasses, it is possible to provide wheat- and gluten-free foods, which are a countermeasure against celiac disease and wheat allergies caused by the ingestion of wheat flour. Proteins with moderate hydrophobicity are preferred. A protein with moderate hydrophobicity refers to a protein with a high content of hydrophobic amino acids among its constituent amino acids. In other words, the inclusion of a large amount of hydrophobic amino acids reduces the water solubility of the protein, forming a hydrophobic protein. Examples of hydrophobic amino acids include leucine, isoleucine, valine, phenylalanine, proline, glutamine, and asparagine. The content of the grass-derived protein relative to the total mass of the solid particles is 50 to 100% by mass. The content of the grass plant-derived protein relative to the total mass of the solid particles is preferably 70 to 100% by mass, more preferably 75 to 100% by mass, even more preferably 80 to 100% by mass, particularly preferably 85 to 100% by mass, especially preferably 90 to 100% by mass, and most preferably 95 to 100% by mass, or even 100% by mass. When the content of the grass plant-derived protein relative to the total mass of the solid particles is within this specific concentration range, the solid particles (grass plant-derived protein) are preferably present at the oil-water interface, thereby achieving high emulsion stability. For example, when a large amount of inorganic particles with a high specific gravity, such as silica, are present as solid particles, the composition may feel rough in the mouth, impairing the taste, or the particles themselves may settle, making it difficult to adsorb to the oil-water interface, making it difficult to produce a stable oil-in-water emulsion composition. Furthermore, even if some of the inorganic particles can be adsorbed to the oil-water interface, there is a concern that they will detach from the interface due to the influence of gravity due to their large specific gravity, which will impair the emulsion stability of the emulsion composition. Furthermore, when used in food, the solid particles are preferably food ingredients or food additives, more preferably food ingredients, from the viewpoint of ensuring safety suitable for consumption.When solid particles other than the grass family plant-derived protein that have a relatively strong affinity for the aqueous phase component are present, it is presumed that the solid particles other than the grass family plant-derived protein are shallowly adsorbed to the oil-water interface (penetration from the aqueous phase component side to the oil phase component side) and are easily detached by shear caused by convection during stirring and heating, etc. In this case, from the viewpoint of stress relaxation, it is preferable that the content of the easily deformable protein material is high, and it is preferable that a grass family plant-derived protein that retains relatively hydrophobic properties is used, and further that the content thereof is within the above-mentioned specific range.

[0014] Proteins with appropriate hydrophobicity can also be evaluated by measuring the contact angle with water. The contact angle is usually 0 degrees or more, preferably 5 degrees or more, more preferably 10 degrees or more, even more preferably 15 degrees or more, particularly preferably 20 degrees or more, especially preferably 40 degrees or more, most preferably 50 degrees or more, and especially preferably 65 degrees or more. There is no upper limit to the contact angle, but from the viewpoint of handling during production, such as dispersion in an aqueous phase, the contact angle is usually less than 180 degrees, preferably 150 degrees or less, more preferably 130 degrees or less, even more preferably 110 degrees or less, particularly preferably 90 degrees or less, and most preferably 80 degrees or less. The contact angle can be measured by tableting solid particles, dropping water under its own weight, and measuring the contact angle at room temperature (e.g., 25°C) using a contact angle measuring device. Furthermore, the contact angle is measured over time after the water is dropped, and in order to minimize the influence of surface irregularities and liquid absorption into the porous portions of the tablet, the contact angle at the time of droplet landing (t=0) is calculated by linear approximation using the measured value at which the change in contact angle with time (t) after droplet landing is approximately linear. This can be used as the contact angle of water with the solid particles. When the contact angle of water with the solid particles is set within the above range, the wettability of the solid particles becomes moderately hydrophobic. When such a substance having moderate hydrophobicity is used as the solid particles, it is possible to efficiently emulsify water with fats and oils (animal fats, vegetable fats, edible oils, etc.) that are less polar than hydrocarbons, and form an emulsion structure in which the solid particles are adsorbed to the oil-water interface, thereby obtaining an emulsion composition with good emulsion stability.

[0015] Examples of proteins with appropriate hydrophobicity include glutelin, prolamin, and globulin, with glutelin and prolamin being preferred due to their higher hydrophobicity. Examples of prolamin include zein, gliadin, hordein, and kafirin. The proteins derived from grass plants are preferred because they are primarily composed of glutelin and prolamin and have high hydrophobicity. In particular, compared to proteins derived from legumes, which are primarily composed of globulin, the higher hydrophobicity of these proteins allows solid particles to be adsorbed to the water-oil interface in a suitable structure, thereby enabling the formation of a stable oil-in-water emulsion composition.

[0016] Furthermore, the taste, color, and odor of the solid particles themselves may affect oral intake applications such as food. Therefore, from the viewpoint of flavor, it is preferable to use proteins derived from grasses (rice-derived proteins, rice-derived proteins, polished rice-derived proteins, etc.) rather than maize-derived proteins or wheat-derived proteins, which have distinctive odors. Furthermore, if the solid particles are dark and rich in color, their applications may be limited. For example, when adjusting a food to a desired taste, color, or odor, colored solid particles may require the addition of more seasoning materials, colorants, and flavorings than colorless solid particles. As a result, the number of manufacturing steps and the amount of additives tend to increase, which may lead to increased complexity and cost during manufacturing. Therefore, the solid particles used in this embodiment have an L value of typically 31 or more, preferably 40 or more, more preferably 50 or more, and even more preferably 62 or more. The upper limit of the L value is not limited, but is typically 100 or less. When the solid particles have such a large L value, the appearance of the oil-in-water emulsion composition may be improved.

[0017] The L value of solid particles can be measured using a colorimeter. The L value represents the lightness of the color and is expressed as a numerical value from 0 to 100. An L value of 100 indicates the brightest state (complete white), and an L value of 0 indicates the darkest state (complete black). Measurement methods using a colorimeter can be performed by methods known per se.

[0018] An example of an index for evaluating the nutritional value of protein is the amino acid score. The amino acid score of rice is 61, which is higher than that of other major grains. Other major grains, such as wheat (strong flour), have an amino acid score of 36, and corn (corn grits) have an amino acid score of 31. In other words, rice has a good amino acid balance and is nutritionally excellent. Therefore, in this embodiment, among hydrophobic proteins, rice-derived proteins are particularly preferred. Examples of rice-derived proteins include glutelin (oryzenin), prolamin, globulin, and albumin, with glutelin and prolamin being preferred due to their high hydrophobicity. Furthermore, glutelin and prolamin are preferred because globulin and albumin, which are present in small amounts in rice, are allergenic to some consumers.

[0019] In rice, prolamins are storage proteins accumulated in protein body I, and glutelins are storage proteins accumulated in protein body II. Therefore, globulins and albumins can be separated from rice by, for example, the treatment methods described in "J. Agric. Food Chem. 2000, 48, 3124-3129," extraction or purification methods using water, acid, alkali, organic solvents, salts, and the like, as taught in, for example, "JP Patent Publication No. 2007-68454" or "Japanese Patent No. 5819981," specific decomposition treatments of globulins and albumins using enzymes, or a combination of these treatment methods.

[0020] The amino acid score is a numerical value that indicates the proportion of the most deficient amino acid as a percentage by comparing the amount of essential amino acids per protein in a food with the amino acid pattern proposed in 1985 by a joint committee of the Food and Agriculture Organization of the United Nations (FAO), the World Health Organization (WHO), and the United Nations University (UNU), with a food that satisfies all amino acids being represented as 100. In this specification, the amino acid score is calculated using the commonly used age group for 2 to 5 years old amino acid patterns.

[0021] In one embodiment, the Gramineae plant-derived protein is rice-derived protein, and in another embodiment, the solid particles are composed of rice-derived protein. In yet another embodiment, the content of the rice-derived protein relative to the total mass of the solid particles is typically 50 to 100% by mass, preferably 70 to 100% by mass, more preferably 75 to 100% by mass, even more preferably 80 to 100% by mass, particularly preferably 85 to 100% by mass, especially preferably 90 to 100% by mass, and most preferably 95 to 100% by mass, or even 100% by mass. In yet another embodiment, the content of the at least one protein selected from glutelin and prolamin, relative to the total mass of the solid particles, may be 0.1 to 100% by mass, preferably 1 to 100% by mass, more preferably 5 to 100% by mass, even more preferably 10 to 100% by mass, especially preferably 50 to 100% by mass, particularly preferably 70 to 100% by mass, especially preferably 75 to 100% by mass, especially preferably 80 to 100% by mass, more especially preferably 85 to 100% by mass, even more especially preferably 90 to 100% by mass, and most preferably 95 to 100% by mass.

[0022] In one embodiment, the protein constituting the solid particles may be subjected to physical treatment such as UV irradiation, heat, or pressure, or chemical treatment such as acid, alkali, denaturant (e.g., urea, guanidine hydrochloride, organic solvents such as alcohol, surfactants), enzyme, oxidizing agent, reducing agent, or chelating agent. By performing such treatment, the protein can be physically and / or chemically modified (denatured, etc.), thereby controlling the wettability of the protein or particles formed from the protein (protein aggregates, protein-containing complexes) themselves. That is, proteins with appropriate wettability are more likely to be present at the interface to be stabilized (the interface between the oil phase and the aqueous phase), thereby forming a stable oil-in-water emulsion composition. Furthermore, treatments such as heating, pressurization, or UV irradiation can also be expected to have a sterilizing effect that prevents spoilage of the material itself.

[0023] The treatment may be performed alone, or two or more arbitrarily selected treatments may be performed simultaneously or separately. For example, a denaturant is added to a medium containing a protein, and heat is applied. This allows denaturation treatment by the denaturant and denaturation treatment by heat to be performed simultaneously. The denaturation treatment method can be selected taking into consideration the type of protein to be denatured, the required degree of denaturation, etc. For example, when performing heat treatment, dry heating or wet heating may be used. There are no limitations on the equipment used, but in the case of dry heating, for example, a roasting equipment, a hot air heating equipment, or a microwave heating equipment can be used. In the case of wet heating, a humidified heating equipment, a steaming equipment, or a steam heating equipment can be used. The heating temperature is usually 30°C or higher, preferably 40°C or higher, more preferably 50°C or higher, more preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher. The upper limit of the heating temperature is a temperature at which the protein does not completely decompose or evaporate, i.e., less than 200°C. The heat treatment time may be any time, and is usually 10 seconds or more, preferably 30 seconds or more, more preferably 1 minute or more, more preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, and particularly preferably 30 minutes or more.

[0024] The shape of the solid particles is not limited, and examples thereof include spherical, rod-like, string-like, gel-like, mesh-like, porous, needle-like, and flake-like shapes. When the solid particles are gel-like, they may be shrunk or swollen. The solid particles may be formed of a single component or a mixture of multiple different components. The solid particles may or may not form aggregates or associations. When the solid particles form aggregates or associations, they may have an entanglement structure, a crosslinked structure due to hydrogen bonds, ionic bonds, intermolecular forces, or the like, between the solid particles.

[0025] The primary particle size of the solid particles is not particularly limited and may be appropriately selected depending on the particle size of the oil phase, the type of protein constituting the solid particles, and the like. The primary particle size is usually 0.001 μm or more, preferably 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and particularly preferably 0.5 μm or more, and usually 50 μm or less, preferably 5 μm or less, more preferably 1 μm or less, and particularly preferably 0.9 μm or less. The primary particle size of the solid particles is, for example, the average particle size of particles observed on a magnified particle image obtained by scanning electron microscope (SEM) measurement. The number of particles observed may be 5 or more, 20 or more, 40 or more, 100 or more, or 200 or more. When commercially available solid particles are used, the primary particle size of the solid particles may be determined by referring to the catalog values.

[0026] The average particle size of the solid particles is not particularly limited as long as the effects of the present invention are achieved, and can be appropriately selected depending on the particle size of the oil phase, the type of protein constituting the solid particles, etc. The volume-based average particle size of the solid particles dispersed in a dilute state in a liquid can be usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.5 μm or more, particularly preferably 1 μm or more, especially preferably 5 μm or more, and most preferably 10 μm or more, and usually 100 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, particularly preferably 40 μm or less, 35 μm or less, especially preferably 30 μm or less, 25 μm or less, and most preferably 20 μm or less, 15 μm or less. The lower and upper limits of the volume-based average particle diameter can be arbitrarily combined, and in one embodiment, it is 0.01 μm or more and 100 μm or less, 0.01 μm or more and 50 μm or less, 0.05 μm or more and 40 μm or less, 0.01 μm or more and 35 μm or less, 0.01 μm or more and 30 μm or less, 0.1 μm or more and 30 μm or less, 0.1 μm or more and 25 μm or less, 1 μm or more and 20 μm or less, and 0.01 μm or more and 15 μm or less. In another embodiment, it is 3 μm or more and 50 μm or less, 5 μm or more and 30 μm or less, and in still another embodiment, it is 10 μm or more and 20 μm or less. Here, the dilute state refers to any concentration, but refers to a concentration that can be measured using a laser diffraction / scattering particle size distribution analyzer, such as a flow type. The concentration to be measured may be typically 20% by mass or less, preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.1% by mass or less, and particularly preferably 0.02% by mass or less, relative to the total mass of the sample to be measured. The volume-based median diameter of the solid particles dispersed in a dilute state in a liquid may be typically 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.5 μm or more, particularly preferably 1 μm or more, especially preferably 5 μm or more, and most preferably 10 μm or more, and typically 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, particularly preferably 40 μm or less, especially preferably 30 μm or less, and most preferably 20 μm or less.The lower limit and upper limit of the volume-based median diameter can be combined arbitrarily, and in one embodiment, it is 0.01 μm or more and 100 μm or less, 0.05 μm or more and 80 μm or less, 0.1 μm or more and 60 μm or less, 1 μm or more and 50 μm or less, or 3 μm or more and 50 μm or less, in another embodiment, it is 5 μm or more and 30 μm or less, and in still another embodiment, it is 10 μm or more and 20 μm or less. The number-based average particle size of the solid particles dispersed in a dilute state in the liquid is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.5 μm or more, particularly preferably 1 μm or more, especially preferably 5 μm or more, and most preferably 5.5 μm or more, and is usually 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, especially preferably 30 μm or less, especially preferably 10 μm or less, and most preferably 8 μm or less. The lower limit and upper limit of the number-based average particle diameter can be combined arbitrarily, and in one embodiment, it is 0.01 μm or more and 100 μm or less, 0.05 μm or more and 80 μm or less, 0.1 μm or more and 60 μm or less, 1 μm or more and 50 μm or less, or 5 μm or more and 30 μm or less, in another embodiment, it is 5 μm or more and 10 μm or less, and in still another embodiment, it is 5.5 μm or more and 8 μm or less. The number-based median diameter of the solid particles dispersed in a dilute state in a liquid is usually 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.5 μm or more, particularly preferably 1 μm or more, especially preferably 3 μm or more, and most preferably 5 μm or more, and is usually 100 μm or less, preferably 80 μm or less, more preferably 60 μm or less, even more preferably 50 μm or less, especially preferably 30 μm or less, especially preferably 10 μm or less, and most preferably 6 μm or less.The lower limit and upper limit of the number-based median diameter can be combined arbitrarily, and in one embodiment, it is 0.01 μm or more and 100 μm or less, 0.05 μm or more and 80 μm or less, 0.1 μm or more and 60 μm or less, 1 μm or more and 50 μm or less, or 5 μm or more and 30 μm or less, in another embodiment, it is 5 μm or more and 10 μm or less, and in still another embodiment, it is 5 μm or more and 6 μm or less.

[0027] The size of solid particles in a liquid can be measured, for example, using a laser diffraction / scattering particle size distribution analyzer to measure the particle size distribution, average particle size, or median size of solid particles in a powder or dispersed state in a liquid. The analysis conditions can be either number-based or volume-based, but volume-based analysis is more preferred. When measurement using a laser diffraction / scattering particle size distribution analyzer is difficult due to insufficient diffracted / scattered light intensity, the particle size distribution, average particle size, or median size of solid particles dispersed in a liquid can be measured by dynamic light scattering. The results of measurement using dynamic light scattering can be analyzed, for example, by the cumulant method. When measurement is possible using either a laser diffraction / scattering particle size distribution analyzer or dynamic light scattering, it is preferable to perform the measurement using a laser diffraction / scattering particle size distribution analyzer. Setting the size of solid particles within the above-mentioned specific range can improve the dispersibility of solid particles in a medium, which is effective in controlling the diameter of oil droplets adsorbed by solid particles to a desired size, leading to stable production of emulsion compositions. In particular, if the size of the solid particles is too large, the solid particles themselves tend to settle due to the influence of gravity, resulting in poor dispersibility and a reduced probability of contact with the oil-water interface. As a result, the solid particles may not be adsorbed in sufficient amounts to the oil-water interface, which may impair the emulsion stability of the emulsion composition. Even if the solid particles are adsorbed to the oil-water interface, they may be strongly affected by gravity and detach from the oil-water interface, thereby impairing the emulsion stability. Furthermore, if the size of the solid particles is too large, the oil-in-water emulsion composition and food containing the solid particles may be prone to feeling rough in the mouth when ingested (food containing the oil-in-water emulsion composition), which is undesirable. That is, by setting the size of the solid particles within the above-mentioned specific range, the adsorbed solid particles can be prevented from detaching from the oil-water interface due to the influence of gravity, thereby achieving excellent emulsion stability. Furthermore, setting the size of the solid particles within the above-mentioned specific range is preferable from the viewpoint of not feeling rough in the mouth when ingesting the oil-in-water emulsion composition and food containing the solid particles, and achieving good taste quality.

[0028] In one embodiment, from the viewpoint of dispersion and particle size control of the solid particles constituting the oil-in-water emulsion composition, it is preferable to separately subject the solid particles to crushing, pulverization, or dispersion treatment. These treatment methods are not limited, and may be performed in a dry or wet manner. A combination of these may be used to perform the crushing and / or pulverization or dispersion treatment stepwise. Examples of wet treatment methods include ultra-high pressure homogenizers, high-pressure homogenizers, homogenizers, jet mills, vibration mills, tumbling mills, high-pressure fluid impact mills, paint shakers, bead mills, ball mills, disk mills, and homomixers. Examples of dry treatment methods include pin mills, jet mills, ball mills, hammer mills, roller mills, cutter mills, and impact shear mills. Ultra-high pressure homogenizers, high-pressure homogenizers, bead mills, cutter mills, and hammer mills are preferred, with ultra-high pressure homogenizers being particularly preferred. When beads are used in wet treatment, beads with a diameter of approximately 0.05 to 5 mm are preferably used. There are no limitations on the material of the beads, but glass beads, special glass beads, alumina beads, zirconia-silica ceramic beads, zirconia beads, silicon nitride beads, steel beads, or the like can be used.

[0029] The temperature during treatment is usually -196°C or higher, preferably -80°C or higher, more preferably -40°C or higher, even more preferably -20°C or higher, particularly preferably 0°C or higher, especially preferably 4°C or higher, and most preferably 20°C or higher. Furthermore, the temperature during treatment is usually 100°C or lower, preferably 90°C or lower, more preferably 80°C or lower, even more preferably 75°C or lower, especially preferably 70°C or lower, especially preferably 65°C or lower, and most preferably 60°C or lower. The treatment time is usually 30 seconds or longer, preferably 1 minute or longer, more preferably 1 minute 30 seconds or longer, more preferably 2 minutes or longer, even more preferably 30 minutes or longer, especially preferably 1 hour or longer, and most preferably 2 hours or longer. The treatment time is usually 10 hours or shorter, preferably 8 hours or shorter, more preferably 7 hours or shorter, and even more preferably 6 hours or shorter. If the treatment time is too short, particle size control tends to become difficult, and if the treatment time is too long, productivity tends to decrease.

[0030] In one embodiment, to produce solid particles that will be a component of an oil-in-water emulsion composition, the disintegrated particles obtained by the above-mentioned production method may be subjected to particle size classification. The classification conditions include a mesh size of typically 150 μm or less, preferably 106 μm or less, more preferably 53 μm or less, even more preferably 45 μm or less, particularly preferably 38 μm or less, and most preferably 20 μm or less. The apparatus used for classification is not particularly limited, but for example, in the case of dry sieving, a rotary sieve, a shaking sieve, a gyrating sieve, or a vibrating sieve can be used; in the case of dry airflow classification, a gravity classifier, an inertia classifier, or a centrifugal classifier (classifier, cyclone, etc.) can be used; and in the case of wet sieving, a mechanical wet classifier, a hydraulic classifier, a sedimentation classifier, or a centrifugal wet classifier can be used.

[0031] In one embodiment, the size of solid particles present at the aqueous phase-oil phase interface in an oil-in-water emulsion composition is not particularly limited as long as the effects of the present invention are achieved. The number-based average particle size of such solid particles is typically 0.01 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.2 μm or more, particularly preferably 0.5 μm or more, especially preferably 0.7 μm or more, and most preferably 1 μm or more, and is typically 50 μm or less, preferably 30 μm or less, more preferably 20 μm or less, even more preferably 10 μm or less, particularly preferably 8 μm or less, especially preferably 6 μm or less, and most preferably 3 μm or less. The lower and upper limits of the average particle size can be arbitrarily combined. In one embodiment, the range is 0.05 μm to 30 μm and 0.1 μm to 20 μm, in another embodiment, 0.5 μm to 15 μm, and in yet another embodiment, 1 μm to 10 μm. The number-based average particle size of solid particles present at the aqueous phase-oil phase interface refers to the average particle size of particles observed on a magnified particle image obtained by measurement using, for example, an optical microscope or a scanning electron microscope (SEM). Observation is preferably performed using a scanning electron microscope. The number of particles observed may be 5 or more, 40 or more, 100 or more, or 200 or more, for example, 100. When measurement using a laser diffraction / scattering particle size distribution analyzer is difficult due to insufficient intensity of diffracted / scattered light, the particle size distribution, average particle size, or median size of solid particles dispersed in a liquid can be measured by dynamic light scattering. Measurement results using dynamic light scattering can be analyzed, for example, by the cumulant method.

[0032] In one embodiment, the content of solid particles in the oil-in-water emulsion composition is not particularly limited as long as it is an amount that can normally be contained in an oil-in-water emulsion composition, but is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.05% by mass or more, even more preferably 0.1% by mass or more, particularly preferably 0.5% by mass or more, especially preferably 1% by mass or more, and most preferably 2% by mass or more, relative to the total mass of the oil-in-water emulsion composition, and is usually 50% by mass or less, preferably 40% by mass or less, more preferably 30% by mass or less, particularly preferably 20% by mass or less, especially preferably 10% by mass or less, and most preferably 5% by mass or less. The lower and upper limits of the solid particle content can be arbitrarily combined, and in one embodiment, it can be 1% by mass or more to 30% by mass or less, 2% by mass or more to 20% by mass or less, or 2% by mass or more to 10% by mass or less, relative to the total mass of the oil-in-water emulsion composition, and in another embodiment, it can be 2% by mass or more to 5% by mass or less.

[0033] (Oil Phase Component) In one embodiment, the oil or fat contained in the oil-in-water emulsion composition forms an oil phase, and may be referred to herein as an oil phase component. The oil phase component is not particularly limited as long as it is one that can be used in an oil-in-water emulsion composition. Examples of such oil phase components include unsaturated higher fatty acid hydrocarbons, unsaturated higher fatty acids, animal and vegetable oils and fats, isoprenoids including squalene and tocopherol, higher alcohols, synthetic ester oils, glycol higher fatty acid esters, saturated fatty acids, and unsaturated fatty acids.

[0034] The oil phase component preferably contains a component that can be used for food (hereinafter referred to as "edible oils and fats"), and any edible oils and fats can be used. Examples of the edible oils and fats that can be used include physiologically functional oils and fats, fat-soluble pigments, and antioxidants. Examples of the edible oils and fats include vegetable oils and fats such as rapeseed oil, rice oil, soybean oil, corn oil, safflower oil, sunflower oil, cottonseed oil, sesame oil, olive oil, palm oil, palm kernel oil, coconut oil, linseed oil, macadamia seed oil, camellia seed oil, tea seed oil, rice bran oil, and cocoa butter; animal oils and fats such as milk fat, beef tallow, lard, chicken fat, mutton tallow, and fish oil; and oils and fats obtained by processing liquid or solid vegetable oils or animal oils such as these by refining, deodorizing, fractionating, hardening, or interesterification. For example, hardened oils and processed oils such as hardened coconut oil and hardened palm kernel oil; and liquid oils or solid fats obtained by fractionating these oils and fats. One or more of the following can be used. In addition, physiologically functional oils and fats can also be used, specific examples of which include docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), arachidonic acid, α-linolenic acid, γ-linolenic acid, and medium-chain triglycerides (MCT). These oils and fats can be used alone or in mixtures. Fat-soluble pigments and antioxidants can also be used, specific examples of which include carotenoid pigments such as annatto pigment, β-carotene, paprika pigment, carrot carotene, and dinaliella carotene, Monascus pigment, chlorophyll, turmeric pigments such as curcumin (curcuminoid), and edible tar-based pigments. Antioxidants include plant extracts such as rosemary extract, tea extract, green coffee bean extract, grape seed extract, and bayberry extract, tocopherol, tocotrienol, ascorbyl palmitate, dibutylhydroxytoluene, and butylhydroxyanisole.

[0035] From the viewpoint of taste, room temperature solid fats are particularly preferred as the oil phase component. Room temperature solid fats are solid fats that exist in a solid state at room temperature (e.g., 25°C), and examples thereof include beef tallow, lard, palm stearin, palm mid-melting point fraction, hardened coconut oil, hardened palm kernel oil, hardened rapeseed oil, hardened castor oil, hardened soybean oil, hardened beef tallow oil, and hardened fish oil. It is also more preferred to use vegetable oils and fats, hardened vegetable oils, or processed vegetable oils and fats. By using these oils and fats to prepare an emulsion composition, it is possible to adjust the taste (flavor, texture) to be similar to that of animal-derived foods, and it is possible to provide an oil-in-water emulsion composition and a food containing the same having a suitable taste.

[0036] More preferred oil phase components are palm oil, palm stearin, palm kernel oil, coconut oil, cocoa butter, milk fat, beef tallow, lard, chicken fat, mutton tallow, hardened coconut oil, or hardened palm kernel oil, or other vegetable oils and fats; hardened animal fats; solid fats obtained by fractionating vegetable oils and fats or hardened or processed animal fats; or medium-chain triglycerides (MCTs). More preferred oil phase components are palm kernel oil, coconut oil, milk fat, hardened coconut oil, hardened palm kernel oil, or medium-chain triglycerides (MCTs). Still more preferred oil phase components are palm kernel oil, coconut oil, hardened coconut oil, or hardened palm kernel oil, and particularly preferred oil phase component is hardened coconut oil. These oils and fats may be used alone or as a mixture.

[0037] In particular, for edible fats and oils, the proportion of unsaturated fatty acids other than saturated fatty acids, i.e., including trans fatty acids, in all fatty acids bound to triglyceride molecules, which are the main components, is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, particularly preferably 10% by mass or less, and most preferably 5% by mass or less, relative to the total mass of all fatty acids.Furthermore, for edible fats and oils, the proportion of fatty acids having 12 or less carbon atoms in all fatty acids bound to triglyceride molecules is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, particularly preferably 10% by mass or more, and most preferably 30% by mass or more, relative to the total mass of all fatty acids. Furthermore, it is preferable that the iodine value of the edible oil or fat is usually 60.0 or less, preferably 50.0 or less, more preferably 30.0 or less, even more preferably 20.0 or less, particularly preferably 10.0 or less, and most preferably 5.0 or less, since this results in no oxidized odor when heated and a good flavor. Furthermore, it is preferable that the SFC (solid fat content) of the edible oil or fat at 10°C is usually 0% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, even more preferably 40% by mass or more, and most preferably 50% by mass or more, relative to the total mass of the edible oil or fat, in order to produce a composition with a good flavor.

[0038] Here, the solid fat content (SFC) is generally measured by a method using conventional pulse NMR, and there is not much difference even if the solid fat index (SFI) obtained by thermal analysis is used. Furthermore, in order to produce a composition with a good flavor, it is preferable that the slip melting point of the edible oil or fat is generally −20° C. or higher, preferably −10° C. or higher, more preferably 10° C. or higher, even more preferably 15° C. or higher, particularly preferably 20° C. or higher, and most preferably 25° C. or higher. The upper limit of this slip melting point is preferably 70° C. or lower, more preferably 60° C. or lower, even more preferably 50° C. or lower, and most preferably 45° C. or lower, which is suitable for obtaining good emulsion stability.

[0039] In one embodiment, the oil constituting the oil phase of the oil-in-water emulsion composition forms oil droplets. In this specification, the oil droplets may be simply referred to as the oil phase, and the term "average particle size of the oil phase" refers to the average particle size of the oil droplets. Furthermore, the term "median diameter of the oil phase" refers to the median diameter of the oil droplets. In another embodiment, the average particle size of the oil phase is preferably 2.2 μm or more. The average particle size of the oil phase refers to the size of the discontinuous phase of the oil-in-water emulsion composition, i.e., the average diameter of the oil phase in an O / W emulsion or a W / O / W emulsion. By setting the average particle size of the oil phase to the above value, the texture, appearance, touch, viscosity, stability, and the like can be improved. The average particle size of the oil phase is typically greater than 0.5 μm, preferably greater than 1 μm, more preferably greater than 2.2 μm, even more preferably greater than 3 μm, more preferably greater than 5 μm, and even more preferably greater than 9 μm. Although there is no upper limit, the average particle size of the oil phase is usually 1000 μm or less, preferably 500 μm or less, more preferably 250 μm or less, even more preferably 100 μm or less, particularly preferably 50 μm or less, especially preferably 30 μm or less, and most preferably 20 μm or less. The lower and upper limits of the average particle size can be arbitrarily combined. In one embodiment, it is 5 μm or more and 50 μm or less, in another embodiment, it is 5 μm or more and 40 μm or less, and in still another embodiment, it is 5 μm or more and 15 μm or less. Here, the preferred range of the median diameter of the oil phase is the same as the preferred range of the average particle size of the oil phase described above. Such an emulsion structure can be confirmed by observation with a polarizing microscope. Furthermore, the size of the discontinuous phase, i.e., the oil phase, is the average size of the major axis of the discontinuous phase as confirmed by observation with a polarizing microscope. The number of discontinuous phases to be confirmed may be 10 or more, 20 or more, 40 or more, 50 or more, 100 or more, or 200 or more. Alternatively, the size of the discontinuous phase of the oil-in-water emulsion composition, i.e., the particle size distribution, median size, or average particle size of the oil phase in the O / W emulsion, may be measured using a laser diffraction / scattering particle size distribution measuring device or a measuring device using a dynamic light scattering method.

[0040] In one embodiment, the content of the oil phase component, i.e., fat or oil, in the oil-in-water emulsion composition is not particularly limited as long as it is an amount that allows the formation of an oil-in-water emulsion composition, but is usually 0.1% by mass or more, preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, particularly preferably 10% by mass or more, especially preferably 20% by mass or more, and most preferably 30% by mass or more, relative to the total mass of the oil-in-water emulsion composition. Furthermore, the content of the oil or fat, relative to the total mass of the oil-in-water emulsion composition, is usually less than 80% by mass, preferably 70% by mass or less, more preferably 50% by mass or less, even more preferably 40% by mass or less, particularly preferably 30% by mass or less, especially preferably 20% by mass or less, and most preferably 10% by mass or less. The lower and upper limits of the content of the oil phase component, i.e., the oil and fat content in the oil-in-water emulsion composition, can be combined arbitrarily, and in one embodiment, the content is 0.1% by mass or more and 30% by mass or less, relative to the total mass of the oil-in-water emulsion composition, in another embodiment, 1% by mass or more and 20% by mass or less, relative to the total mass of the oil-in-water emulsion composition, and in still another embodiment, 3% by mass or more and 10% by mass or less, relative to the total mass of the oil-in-water emulsion composition. In the oil-in-water emulsion composition of this embodiment, it is preferable that the change in diameter of the oil phase, which is the discontinuous phase of the emulsion composition, is small before and after heating, such as sterilization. The change in diameter before and after freezing or heating is calculated by taking the median diameter (D50) of the oil-in-water emulsion composition before freezing or heating as 100% and calculating the percentage difference from the median diameter (D50) of the oil-in-water emulsion composition after freezing or heating. The median diameter (D50) after heating may be ±100% or less, ±90% or less, ±80% or less, ±75% or less, ±50% or less, ±30% or less, ±20% or less, or ±10% or less.

[0041] (Aqueous Phase Components) In one embodiment, the water contained in the oil-in-water emulsion composition forms the aqueous phase, which is the continuous phase in the oil-in-water emulsion composition. The components forming the aqueous phase may be any components that are typically incorporated into the oil-in-water emulsion composition to form the aqueous phase. Such aqueous phase components include at least water, and may also include a lower alcohol, a polyhydric alcohol, or the like.

[0042] In one embodiment, the water content in the oil-in-water emulsion composition is not particularly limited as long as it is an amount that can form an oil-in-water emulsion composition, but is usually 20% by mass or more, preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% by mass or more, particularly preferably 60% by mass or more, especially preferably 70% by mass or more, and most preferably 80% by mass or more, based on the total mass of the oil-in-water emulsion composition. Furthermore, the water content is usually less than 100% by mass, preferably 99% by mass or less, more preferably 98% by mass or less, even more preferably 97% by mass or less, particularly preferably 95% by mass or less, especially preferably 90% by mass or less, and most preferably 80% by mass or less, based on the total mass of the oil-in-water emulsion composition. The lower and upper limits of the water content in the oil-in-water emulsion composition can be arbitrarily combined. In one embodiment, the water content is 80% by mass or more but less than 100% by mass, relative to the total mass of the oil-in-water emulsion composition. In another embodiment, the water content is 80% by mass or more but less than 99% by mass, relative to the total mass of the oil-in-water emulsion composition. In yet another embodiment, the water content is 90% by mass or more but less than 98% by mass, relative to the total mass of the oil-in-water emulsion composition. In one embodiment, the grass plant-derived protein used as the solid particles is prepared from a commercially available grass plant-derived protein raw material. For example, commercially available grass plant-derived protein raw materials contain impurities, at least a portion of which is an ionic amphiphilic substance. Examples of ionic amphiphilic substances include phospholipids, ionic glycolipids, and fatty acids. Among these, phospholipids are preferred. Examples of phospholipids include lecithin, lysolecithin, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, lysophosphatidylcholine, phosphatidylethanolamine, N-acylphosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid. Among these, lysolecithin and lysophosphatidylcholine are preferred. Furthermore, as the ionic amphiphilic substance as an impurity, a low-molecular-weight ionic amphiphilic substance is preferred, and its molecular weight is preferably 5,000 or less, more preferably 3,000 or less, even more preferably 2,000 or less, and most preferably 1,000 or less.The amount of ionic amphiphilic substance introduced into the emulsion composition, derived from the raw materials used, is preferably within a range that does not interfere with the adsorption of solid particles to the water-oil interface. From this perspective, the mass ratio of the content of ionic amphiphilic substance to the content of proteins (grass-derived proteins and other proteins, or grass-derived proteins) constituting the emulsion composition is usually 1.0 or less, preferably 0.50 or less, more preferably 0.10 or less, even more preferably 0.050 or less, particularly preferably 0.040 or less, especially preferably 0.030 or less, most preferably 0.021 or less, and especially preferably 0. The lower limit is usually 0 or more, preferably 0.0000010 or more, 0.000010 or more, more preferably 0.00010 or more, even more preferably 0.0010 or more, especially preferably 0.0020 or more, especially preferably 0.0050 or more, 0.01 or more. The upper and lower limits of the mass ratio of the ionic amphiphilic substance content to the protein content (grass plant-derived protein and other protein, preferably grass plant-derived protein) constituting the emulsion composition can be arbitrarily combined, and may be 0 to 1.0, 0 to 0.50, 0 to 0.10, 0 to 0.05, 0 to 0.02, or 0.00010 to 0.10. Here, for a grass plant-derived protein raw material, the mass ratio of the ionic amphiphilic substance content to the total amount of grass plant-derived protein is usually 1.0 or less, preferably 0.50 or less, more preferably 0.10 or less, even more preferably 0.050 or less, particularly preferably 0.025 or less, especially preferably 0.010 or less, and most preferably 0.0050 or less. The lower limit is usually 0 or more, preferably 0.0000010 or more, 0.000010 or more, more preferably 0.00010 or more, even more preferably 0.0010 or more, particularly preferably 0.0020 or more, and especially preferably 0.0050 or more, 0.01 or more. The upper and lower limits of the mass ratio of the content of the ionic amphiphile to the total amount of the protein derived from a grass family plant can be arbitrarily combined, and may be 0 or more and 1.0 or less, 0 or more and 0.50 or less, 0 or more and 0.10 or less, 0 or more and 0.05 or less, 0 or more and 0.02 or less, or 0.00010 or more and 0.10 or less.Here, the "ratio of ionic amphiphile content to grass plant-derived protein" refers to the "mass ratio of the ionic amphiphile content to the total solid content of the grass plant-derived protein" or the "mass ratio of the ionic amphiphile content to the protein content contained in the grass plant-derived protein." The protein content can be measured by known methods. Furthermore, when the grass plant-derived protein contains, in particular, an ionic amphiphile (such as a phospholipid) or a low molecular weight amphiphile, the ionic amphiphile or low molecular weight amphiphile will be present before the solid particles adsorb to the oil-water interface to be stabilized. For example, the oil droplet surface will temporarily become highly negatively charged in absolute terms, which may inhibit the adsorption of the negatively charged solid particles due to electrostatic repulsion or physical obstruction, thereby undesirably inhibiting the adsorption of the solid particles to the interface. In other words, by using protein raw materials with mass ratios within the above ranges and by preparing an emulsified composition with mass ratios within the above ranges, solid particles can be efficiently adsorbed to the water-oil interface, forming an emulsified structure necessary for exhibiting high heat resistance, and as a result, an emulsified composition with excellent emulsion stability can be obtained. Note that, in this specification, the term "mass ratio of B to A" and similar expressions refer to the ratio of B to A, i.e., the magnitude of B when A is taken as 1.

[0043] (Alkali Metal Salt) In one embodiment, the oil-in-water emulsion composition contains an alkali metal salt, and the pH of the oil-in-water emulsion composition is adjusted to exceed 7. The alkali metal salt is not particularly limited as long as it is acceptable for addition to foods and can adjust the pH of the oil-in-water emulsion composition to exceed 7. Examples of the alkali metal salt include sodium or potassium salts of carbonate or bicarbonate, i.e., sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate. The alkali metal salts may be used alone or in combination of two or more. The alkali metal salt may be an alkali metal salt of an inorganic acid or an alkali metal salt of an organic acid. Examples of alkali metal salts of organic acids include trisodium citrate, sodium acetate, and disodium succinate. Examples of alkali metal salts of inorganic acids include potassium salts of carbonate or bicarbonate, such as potassium bicarbonate and potassium carbonate; sodium salts of carbonate or bicarbonate, such as sodium carbonate and sodium bicarbonate; potassium phosphates, such as dipotassium hydrogen phosphate and potassium dihydrogen phosphate; and sodium phosphates, such as disodium hydrogen phosphate and sodium dihydrogen phosphate. The alkali metal salt is preferably an alkali metal salt of an inorganic acid. Compared to alkali metal salts of organic acids, alkali metal salts of inorganic acids are less susceptible to oxidation-reduction and are more stable, allowing for suitable adjustment of the pH of the aqueous phase, which is a component of an oil-in-water emulsion composition, and the pH of the oil-in-water emulsion composition itself. This enables stable production of oil-in-water emulsions and foods containing the same, and is believed to enable the quality of the oil-in-water emulsion composition and foods containing the same after production to be maintained over an extended period of time. In other words, the oil-in-water emulsion composition of the present invention exhibits excellent emulsion stability, maintaining the structure in which solid particles are adsorbed to the oil-water interface even before and after heating. Also, from the viewpoint of low cost and easy availability, the alkali metal salt is preferably an alkali metal salt of an inorganic acid, more preferably an alkali metal salt of carbonate or bicarbonate, still more preferably a sodium salt of carbonate or bicarbonate, and particularly preferably sodium bicarbonate or sodium carbonate.In one embodiment, the content of the alkali metal salt in the oil-in-water emulsion composition can be adjusted so that the pH of the oil-in-water emulsion composition exceeds 7. In another embodiment, the content of the alkali metal salt in the oil-in-water emulsion composition can be adjusted so that the pH of the oil-in-water emulsion composition exceeds 7 and is 8.9 or less. In yet another embodiment, the content of the alkali metal salt in the oil-in-water emulsion composition can be adjusted so that the pH of the oil-in-water emulsion composition is 7.5 or more and 8.5 or less. In yet another embodiment, the content of the alkali metal salt in the oil-in-water emulsion composition can be adjusted so that the pH of the oil-in-water emulsion composition is 7.7 or more and 8.2 or less. The content of the alkali metal salt is not particularly limited as long as it can be adjusted to a desired pH, but is usually more than 0 mM, preferably 0.00001 mM or more, more preferably 0.001 mM or more, even more preferably 0.01 mM or more, particularly preferably 0.1 mM or more, especially preferably 1 mM or more, and most preferably 5 mM or more, relative to the volume of the oil-in-water emulsion composition. The upper limit is usually less than 100 mM, preferably 98 mM or less, more preferably 95 mM or less, even more preferably 90 mM, especially preferably 50 mM or less, especially preferably 30 mM or less, and most preferably 10 mM or less. The lower and upper limits of the alkali metal salt content can be arbitrarily combined. In one embodiment, the alkali metal salt content can be 0.00001 mM or more but less than 100 mM, 0.00001 mM or more but less than 98 mM, 0.00001 mM or more but less than 95 mM, 0.00001 mM or more but less than 50 mM, 0.00001 mM or more but less than 30 mM, 0.00001 mM or more but less than 10 mM, 0.001 mM or more but less than 10 mM, 0.01 mM or more but less than 10 mM, or 0.1 mM or more but less than 10 mM, relative to the volume of the oil-in-water emulsion composition. Furthermore, when vegetable oil is used as the oil phase, the concentration can be calculated assuming a specific gravity of 0.92. The pH can be measured by a known method, for example, using a pH meter. When used or consumed as a food, it is desirable to prepare (dilute) the composition so that the content is equal to or less than the upper limit specified by the government.In conventional oil-in-water emulsion compositions, for example, when heated at 121°C for 30 minutes, as applied in retort processing, although oil separation is not observed in the oil-in-water emulsion composition, aggregation of the solid particles themselves and aggregation of the oil phase (oil droplets) via solid particles adsorbed at the oil-water interface are usually observed. In contrast, as in the first aspect of the present invention, by adjusting the pH of the oil-in-water emulsion composition to the above range, it was unexpectedly found that neither oil separation nor aggregation of the solid particles nor the oil phase (oil droplets) is observed even when heated at 121°C for 30 minutes. The reason for this is presumably that by adjusting the pH of the oil-in-water emulsion composition as described above, the pH becomes moderately higher (alkaline) than the isoelectric point of the grass plant-derived protein constituting the solid particles adsorbed to the oil droplets in the oil-in-water emulsion composition, and the protein becomes negatively charged, causing the oil phase (oil droplets) to electrically repel each other and suppress aggregation. Furthermore, by setting the pH of the oil-in-water emulsion composition to the above upper limit or less, hydrolysis or dissolution of solid particles can be suppressed, and dissolution of oil phase components can be suppressed, which is preferable from the viewpoint of suppressing oil separation and aggregation of the oil phase (oil droplets). By using the above specific amount of alkali metal salt, the pH of the oil-in-water emulsion composition can be controlled within a desired range, making it possible to prepare an emulsion composition with excellent heat resistance. If the amount of alkali metal salt added is too small or too large, it is difficult to control the pH of the aqueous phase constituting the oil-in-water emulsion composition, and as a result, the emulsion stability (heat resistance) of the oil-in-water emulsion composition may be impaired.

[0044] (Other Components) In one embodiment, the oil-in-water emulsion composition of the first aspect may further contain a colorant, an antioxidant, a sweetener, a stabilizer, a milk component, a flavoring, a colorant, a salt (excluding the alkali metal salts), an organic acid, or the like, within a range that does not impair the effects of the present invention.

[0045] Examples of sweeteners include the following: sugars: monosaccharides such as glucose, fructose, wood sugar, sorbose, galactose, and isomerized sugar; disaccharides such as sucrose, maltose, lactose, isomerized lactose, and palatinose; oligosaccharides such as fructooligosaccharides, maltooligosaccharides, isomaltooligosaccharides, galactooligosaccharides, coupling sugar, and palatinose; sugar alcohols: monosaccharide alcohols such as erythritol, sorbitol, xylitol, and mannitol; disaccharide alcohols such as maltitol, isomaltitol, and lactitol; trisaccharide alcohols such as maltotriitol, isomaltotriitol, and panitol; tetrasaccharide or higher alcohols such as oligosaccharide alcohols; powdered reduced maltose starch syrup; and high-intensity sweeteners: aspartame, neotame, sucralose, and stevia.

[0046] Stabilizers include galactomannan, xanthan gum, carrageenan, gum arabic, tamarind gum, gellan gum, glucomannan, cellulose, and the like.

[0047] Examples of dairy components include liquids such as milk, processed milk, skim milk, fresh cream, whey, buttermilk, sweetened condensed milk, and evaporated milk; and powdered dairy products such as whole milk powder, skim milk powder, modified milk powder, powdered cream, powdered whey, and buttermilk powder. Buttermilk or buttermilk powder is particularly preferred. Buttermilk is a liquid component called buttermilk or butterserum, which is separated when the milk fat is extracted as butter from cream produced from milk by centrifugation or other methods using churning. This liquid is concentrated to form concentrated buttermilk, and powdered buttermilk powder is further spray-dried. These may be used alone or in combination of two or more. Separately, during the process of separating cream or butter from milk, fermentation with acid-producing bacteria or the addition of an acid such as an organic acid may be performed. However, the buttermilk that can be used in the present invention is preferably one that has not undergone such fermentation or acid addition. Commercially available buttermilk products, such as "Buttermilk Powder" manufactured by Yotsuba Dairy Products Co., Ltd., can be used.

[0048] As mentioned above, from the viewpoint of ensuring that the oil-in-water emulsion composition does not contain any allergens, it is preferable that the milk component does not contain casein or β-lactoglobulin, which are highly allergenic, and it is even more preferable that the milk component does not contain any milk-derived proteins. Furthermore, it is preferable to use casein or β-lactoglobulin after hydrolyzing it with an enzyme or acid to a molecular weight that is sufficiently low so that it does not exhibit allergenicity.

[0049] Any flavoring agent can be used. Examples include vanilla flavorings such as vanilla essence; milk flavors such as milk flavor or butter flavor; and the like, with milk flavors being particularly preferred. The milk flavoring is not particularly limited as long as it is a flavoring containing the aroma components of milk and contains the aroma components characteristic of milk. It may be a chemically synthesized product, a product extracted and purified from milk, or a mixture thereof. However, milk-based flavorings are more preferred, and milk flavorings produced by reacting milk components with enzymes are even more preferred because they can reproduce the natural flavor of milk. These may be used alone or in combination of two or more. Any coloring agent can be used. Examples include cocoa color, β-carotene, annatto color, chili pepper color, turmeric color, oil red color, paprika color, naphthol yellow color, and riboflavin butyrate (VB2).

[0050] Examples of salts (excluding the alkali metal salts) include chlorides such as table salt, potassium chloride, and magnesium chloride; carbonates such as calcium carbonate; phosphates such as disodium phosphate, trisodium phosphate, dipotassium phosphate, and tripotassium phosphate; sodium polyphosphate; citrates such as sodium citrate; and sodium lactate. Magnesium-containing salts are particularly preferred, and examples of salts that can be used in food applications include whey minerals, magnesium chloride, magnesium oxide, magnesium carbonate, magnesium sulfate, bittern (crude seawater magnesium chloride), dolomite, crude salt, magnesium stearate, magnesium monohydrogen phosphate, trimagnesium phosphate, magnesium silicate, magnesium hydroxide, magnesium acetate, magnesium citrate, magnesium malate, magnesium benzoate, magnesium gluconate, magnesium L-glutamate, sepiolite, talc, and phytin.

[0051] Examples of organic acids include fumaric acid, succinic acid, citric acid, tartaric acid, diacetyltartaric acid, malic acid, adipic acid, glutaric acid, and maleic acid.

[0052] In one embodiment, the oil-in-water emulsion composition has the configuration of the first aspect, and thus can provide a highly heat-resistant oil-in-water emulsion composition that does not contain an amphiphilic substance such as a sucrose fatty acid ester, and that does not undergo separation of the oil phase or the formation of aggregates of oil droplets and solid particles, even when subjected to, for example, retort treatment (at 121°C for 30 minutes). That is, one embodiment of the present invention is an oil-in-water emulsion composition that contains solid particles, water, oils and fats, and an alkali metal salt, wherein the solid particles are composed of a protein derived from a grass plant, has a pH greater than 7, and is free of an amphiphilic substance. The content of the amphiphilic substance in the oil-in-water emulsion composition may be less than 0.00001% by mass or even 0% by mass, based on the mass of the oil-in-water emulsion composition. The ratio of the mass of the amphiphilic substance to the mass of the solid particles may be less than 0.00001% by mass or even 0% by mass.

[0053] <Production of the oil-in-water emulsion composition of the first aspect> In one embodiment, the oil-in-water emulsion composition of the first aspect can be produced by a method known per se, for example, by mixing solid particles, an oil phase component, an aqueous phase component, an alkali metal salt, and, if necessary, other components, and stirring the resulting mixture using any stirring device.

[0054] Although not particularly limited, the composition can be specifically prepared by the following method: A production method comprising: a step A1 of mixing an aqueous phase component containing an alkali metal salt with solid particles to form a mixture, and agitating the mixture; a step A2 of mixing the mixture obtained in the previous step with the oil phase component to form a mixture, and agitating the mixture; or a production method comprising: a step A1' of mixing the oil phase component with the solid particles to form a mixture, and agitating the mixture; and a step A2' of mixing the mixture obtained in the previous step with an aqueous phase component in which the alkali metal salt has been dissolved to form a mixture, and agitating the mixture.

[0055] Step A1 is a step for preparing an aqueous phase. In this manner, adding solid particles to an aqueous phase in which an alkali metal salt has been dissolved to prepare a dispersion of solid particles facilitates the formation of an oil-in-water emulsion composition. Here, the pH of the aqueous phase in which the alkali metal salt has been dissolved is preferably adjusted to exceed 7. Step A1' is a step for preparing an oil phase. In this manner, adding solid particles to an oil phase to prepare the oil phase facilitates the formation of an oil-in-water emulsion composition due to the interaction between the oil phase and the solid particles. The stirring of the mixture in steps A1 and A1' may be performed at room temperature and normal pressure, or under heated and / or elevated pressure. There are no limitations on the stirring speed or stirring time, but a speed of 10 rpm or more and 20,000 rpm or less is typically sufficient, and the stirring time is typically 10 seconds or more and 5 hours or less. The stirring speed or stirring time may be changed in stages. Alternatively, a wet atomization apparatus such as that described in the examples (for example, Starburst Lab (manufactured by Sugino Machine Co., Ltd.)) equipped with an oblique collision chamber may be used to cause oblique collision of a mixture of solid particles and an aqueous phase component having an alkali metal salt dissolved therein under ultra-high pressure, thereby atomizing (also referred to as micronization) the solid particles and dispersing them into the aqueous phase.

[0056] Examples of stirring devices include high-pressure emulsifiers, paddle mixers, homogenizers, ultrasonic homogenizers, colloid mills, kneaders, in-line mixers, static mixers, onlaters, and homomixers. Homomixers (homomixers), paddle mixers, and homogenizers are preferred because they can perform sufficient stirring with low energy and low cost. Homomixers are more preferred because they have a wide convection range and can stir the entire mixture uniformly. Different stirring devices may also be used in combination.

[0057] Steps A2 and A2' are steps for preparing an oil-in-water emulsion composition. The stirring of the mixture in step A2 is typically carried out under heated conditions to fully melt the oily component, and is usually carried out at a temperature of 10°C to 100°C, preferably 20°C to 90°C, more preferably 30°C to 90°C, even more preferably 40°C to 90°C, particularly preferably 50°C to 90°C, and most preferably 60°C to 90°C. The stirring speed is usually 10 rpm to 20,000 rpm, and the stirring time is usually 10 seconds to 60 minutes.

[0058] Although there are no limitations on the stirring conditions, stepwise changes in the stirring speed and stirring time can result in the formation of a more stable oil-in-water emulsion composition. Specifically, by finely dispersing oil droplets through high-speed stirring in the first stage and then stirring at a slower speed in the second stage than in the first stage, adsorption of solid particles to the oil-water interface is promoted, resulting in emulsion stabilization. Furthermore, the second stage of stirring can suppress poor adsorption of solid particles to the oil-water interface due to shear forces from the equipment generated during the high-speed stirring in the first stage, and can also suppress detachment of solid particles once adsorbed to the interface from the interface.

[0059] When the stirring conditions are changed stepwise, the stirring speed in the first stage is usually 3000 rpm or more, more preferably 5000 rpm or more, more preferably 7000 rpm or more, and even more preferably 8000 rpm or more. There is no upper limit to the stirring speed, but it is usually 25000 rpm or less, preferably 20000 rpm or less, more preferably 18000 rpm or less, even more preferably 16000 rpm or less, particularly preferably 14000 rpm or less, especially preferably 12000 rpm or less, and most preferably 10000 rpm or less. The stirring time in the first stage is usually 30 seconds or more, preferably 1 minute or more. There is no upper limit to the stirring time, but it is usually 1 hour or less, preferably 30 minutes or less, more preferably 15 minutes or less, and particularly preferably 5 minutes or less.

[0060] When the stirring conditions are changed stepwise, the stirring speed in the second stage may typically be 10 rpm or more, preferably 100 rpm or more, 500 rpm or more, 1000 rpm or more, 2000 rpm or more, or 2500 rpm or more. There is no upper speed limit, but the stirring speed in the second stage may typically be 10,000 rpm or less, preferably 8,000 rpm or less, 6,000 rpm or less, or 3,000 rpm or less. There is no particular limit to the stirring time, but from the viewpoint of promoting adsorption of the solid particles to the oil-water interface, it is typically 30 seconds or more, preferably 1 minute or more, more preferably 10 minutes or more, and even more preferably 20 minutes or more.

[0061] In addition, after preparing the oil-in-water emulsion composition, it is usually 60 ° C or higher, preferably 65 ° C or higher, more preferably 75 ° C or higher, even more preferably 80 ° C or higher, particularly preferably more than 95 ° C, especially preferably 100 ° C or higher, most preferably 110 ° C or higher, and also usually 160 ° C or lower, preferably 150 ° C or lower, usually for 0.01 minutes or more, preferably 0.03 minutes or more, and usually 60 minutes or less, preferably 30 minutes or less. The sterilization method is not particularly limited, but examples include UHT sterilization, retort sterilization, and Joule sterilization. UHT sterilization can be performed by a direct heating method such as a steam injection method in which steam is directly blown into the composition or a steam infusion method in which the composition is heated by injecting steam into the composition; an indirect heating method using a surface heat exchanger such as a plate or tube, and can be performed by a method known per se, for example, a plate-type sterilizer can be used. Furthermore, the oil-in-water emulsion composition of the first aspect of the present invention has high heat resistance, and therefore can be subjected to retort sterilization at 121°C for 30 minutes. This allows the emulsion composition and / or food containing the emulsion composition to be effectively sterilized, making it possible to prepare and provide an emulsion composition that maintains a suitable oil phase (oil droplet) particle size while ensuring safety. Furthermore, when the emulsion composition has high heat resistance that can withstand retort sterilization, it also has the advantage of enabling long-term storage of the emulsion composition and distribution at room temperature with reduced power consumption.

[0062] <Second Aspect> In this specification, the oil-in-water emulsion composition described above is referred to as the second aspect when it comprises solid particles, water, oil, and a polysaccharide, the solid particles being present at the interface between the water and the oil, the solid particles containing a grass family plant-derived protein, and the content of the grass family plant-derived protein relative to the total mass of the solid particles is 50 to 100 mass %.

[0063] (Solid Particles, Oil Phase Component, and Aqueous Phase Component) The oil phase component and the aqueous phase component in the second aspect of the present invention may be the same as the oil phase component and the aqueous phase component contained in the oil-in-water emulsion composition according to the first aspect of the present invention, respectively, and the same applies to preferred aspects. Furthermore, the solid particles comprising a grass plant-derived protein in the second aspect may also be the same as the solid particles composed of a grass plant-derived protein in the first aspect, and the same applies to preferred aspects.

[0064] (Polysaccharides) In one embodiment, the second aspect of the present invention contains a polysaccharide. The polysaccharide is preferably a water-soluble polysaccharide, more preferably an ionic polysaccharide, and even more preferably an acidic polysaccharide (anionic polysaccharide). Examples of ionic polysaccharides include acidic polysaccharides and basic polysaccharides. Acidic polysaccharides (anionic polysaccharides) refer to polysaccharides having an acidic group such as a carboxyl group or a sulfate group in the molecule. Basic polysaccharides refer to polysaccharides having an amino group, which is a basic group, in the molecule. Here, polysaccharides refer to saccharides in which multiple monosaccharides are bonded, and typically saccharides in which 10 or more monosaccharides are bonded. Examples of acidic polysaccharides include carrageenan, pectin, gum arabic, xanthan gum, gellan gum, agar, and tragacanth gum. The acidic polysaccharides may be used alone or in combination of two or more. Xanthan gum is preferred as the acidic polysaccharide. Here, the polysaccharide is preferably a natural polysaccharide. Natural polysaccharides refer to polysaccharides made from naturally occurring components. Naturally occurring components may be produced or extracted by a culture method, or may be extracted from plants, microorganisms, or the like. While synthetically modified versions of these polysaccharides may be used, the use of unmodified versions is preferred from the perspectives of reducing environmental impact and creating clean-label foods, and the use of polysaccharides extracted from plants or microorganisms is even more preferred. In one embodiment, by using the polysaccharides, it was unexpectedly found that, even when the oil-in-water emulsion composition was heated at 121°C for 30 minutes, neither oil coalescence / separation, nor solid particle aggregation, nor aggregation of the oil phase (oil droplets) due to aggregation of solid particles (solid particles adsorbed on oil droplets) present at the water-oil interface, was observed, even without adjusting the pH of the oil-in-water emulsion composition to above 7 using an alkali metal salt, as in the first embodiment. The reason for this is as follows. By using the polysaccharide in an oil-in-water emulsion composition, the solid particles adsorbed on the oil droplets in the oil-in-water emulsion composition are bound to the polysaccharide, and due to the influence of the charge held by the polysaccharide, the oil droplets themselves appear to be charged with the same electrical charge as the polysaccharide (particularly when an acidic polysaccharide is used, they are charged with a negative electrical charge).Therefore, it is presumed that the polysaccharides further bound to the solid particles adsorbed to the oil phase (oil droplets) electrically repel each other, thereby suppressing aggregation of the solid particles and oil droplets. From another perspective, the use of the polysaccharides results in multipoint binding between the solid particles adsorbed to the oil droplets in the oil-in-water emulsion composition and the polymeric polysaccharides, thereby forming oil droplet structures that appear to be covered by the polymeric polysaccharides. It is presumed that the steric hindrance effect of the polysaccharides, which has a wide distribution, suppresses aggregation of the solid particles and oil droplets. For example, when the emulsion composition of the present invention is used in foods containing negatively charged materials such as proteins or many impurities, the use of basic polysaccharides as the polysaccharide may cause aggregation due to electrostatic interactions between the basic polysaccharide and negatively charged substances such as proteins. Aggregates have the disadvantages of impairing emulsion stability, marring the appearance, and causing a rough texture when ingested. Therefore, the use of acidic polysaccharides is preferred from the perspective of suppressing aggregation. In one embodiment, from the viewpoint of the steric hindrance effect, the polysaccharide is preferably a polymer, and its weight-average molecular weight is usually 1,000 or more, preferably 5,000 or more, more preferably 10,000 or more, even more preferably 50,000 or more, particularly preferably 100,000 or more, especially preferably 500,000 or more, and most preferably 1,000,000 or more. It is usually 100,000,000 or less, preferably 50,000,000 or less, and more preferably 10,000,000 or less. The lower and upper limits of the weight-average molecular weight of the polysaccharide can be arbitrarily combined, and in one embodiment, the range can be 1,000 to 100,000,000, 5,000 to 50,000,000, 10,000 to 10,000,000, 50,000 to 10,000,000, 100,000 to 10,000,000, 500,000 to 10,000,000, or 1,000,000 to 10,000,000. The weight-average molecular weight (Mw) can be measured in terms of polystyrene by gel permeation chromatography (GPC).

[0065] In one embodiment, the content of polysaccharides in the oil-in-water emulsion composition is typically greater than 0% by mass, preferably 0.00001% by mass or more, more preferably 0.0001% by mass or more, even more preferably 0.001% by mass or more, particularly preferably 0.005% by mass or more, especially preferably 0.01% by mass or more, and most preferably 0.03% by mass or more, relative to the total mass of the oil-in-water emulsion composition. There is no upper limit, but the content is typically 50% by mass or less, preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 1% by mass or less, particularly preferably 0.5% by mass or less, and especially preferably less than 0.1% by mass.

[0066] The mass ratio of the polysaccharide content to the solid particle content in the oil-in-water emulsion composition is usually greater than 0, preferably 0.000010 or more, more preferably 0.00010 or more, even more preferably 0.0010 or more, particularly preferably 0.005 or more, especially preferably 0.010 or more, and most preferably 0.020 or more. There is no particular upper limit, but it is usually 10 or less, preferably 1 or less, more preferably 0.50 or less, even more preferably 0.20 or less, especially preferably 0.10 or less, especially preferably 0.090 or less, most preferably 0.050 or less, and especially preferably less than 0.042. Here, the "mass ratio of the polysaccharide content to the solid particle content" may be the mass ratio of the polysaccharide content to the content of the solid particles themselves, or may be the mass ratio of the polysaccharide content to the total solid content of the solid particle raw material (grass family plant protein raw material).

[0067] The mass ratio of the polysaccharide content to the fat / oil content in the oil-in-water emulsion composition is usually greater than 0, preferably 0.000010 or more, more preferably 0.00010 or more, even more preferably 0.0010, particularly preferably 0.0050 or more, especially preferably 0.010 or more, and most preferably 0.020 or more. There is no particular upper limit, but it is usually 10 or less, preferably 1.0 or less, more preferably 0.50 or less, even more preferably 0.20 or less, especially preferably 0.10 or less, especially preferably 0.090 or less, and most preferably less than 0.040.

[0068] If the polysaccharide content, the ratio of polysaccharide content to solid particles, or the ratio of polysaccharide content to fats and oils is too high, the addition of excess polysaccharides will excessively thicken the aqueous phase, making handling difficult during the production process and production difficult. Furthermore, if this ratio is too high, the adsorption of polysaccharides to the oil droplet surface will reach saturation, causing depletion of free polysaccharide molecules in the solution, resulting in aggregation between polysaccharide-coated oil droplets (oil droplets stabilized by solid particles), which may lead to a loss of emulsion stability of the oil-in-water emulsion composition. That is, by setting the polysaccharide content, the ratio of polysaccharide content to protein, or the ratio of polysaccharide content to fats and oils within the above-mentioned ranges, the polysaccharides and the oil droplets (oil droplets stabilized by solid particles) will interact favorably, thereby providing a stable emulsion composition with excellent heat resistance according to the present invention. By setting the content within the above-mentioned ranges, an emulsion composition with a suitable viscosity that does not thicken too much and does not impair texture can be provided.

[0069] The preferred range varies depending on the pH of the oil-in-water emulsion composition. By setting the polysaccharide content, the polysaccharide to protein content ratio, or the polysaccharide to fat content ratio within each pH range within the ranges described below, a stable emulsion composition with excellent heat resistance can be provided. Furthermore, by setting the content within the ranges described below, an emulsion composition with a suitable viscosity that does not thicken too much and does not impair the texture can be provided.

[0070] For example, when the pH of the oil-in-water emulsion composition is 6.0 to 7.5, the content of the polysaccharide may be greater than 0% by mass and less than 5% by mass, greater than 0% by mass and less than 1% by mass, greater than 0% by mass and less than 0.5% by mass, 0.00001% by mass or more and less than 1% by mass, or 0.00001% by mass or more and less than 0.5% by mass, relative to the total mass of the oil-in-water emulsion composition.

[0071] When the pH of the oil-in-water emulsion composition is 6.0 to 7.5, the mass ratio of the polysaccharide content to the solid particle content in the oil-in-water emulsion composition may be greater than 0 and less than 1.0, greater than 0 and less than 0.50, greater than 0 and less than 0.10, greater than 0 and less than 0.042, 0.001 or more and 1.0 or less, 0.001 or more and 0.50 or less, or 0.001 or more and 0.10 or less.

[0072] When the pH of the oil-in-water emulsion composition is 6.0 to 7.5, the mass ratio of the polysaccharide content to the fat / oil content in the oil-in-water emulsion composition may be greater than 0 and less than 1.0, greater than 0 and less than 0.50, greater than 0 and less than 0.10, greater than 0 and less than 0.040, 0.001 or more and 1.0 or less, 0.001 or more and 0.50 or less, or 0.001 or more and 0.10 or less.

[0073] In another embodiment, when the pH of the oil-in-water emulsion composition is greater than 5.5 and less than 6.0, the content of the polysaccharides may be 0.04% by mass or more and 0.06% by mass or less, or may be greater than 0% by mass or more and 5% by mass or less, or may be greater than 0% by mass or more and 1% by mass or less, or may be greater than 0% by mass or more and 0.5% by mass or less, or may be greater than 0% by mass or more and less than 0.1% by mass, or may be 0.00001% by mass or more and 1% by mass or less, or may be 0.00001% by mass or more and 0.5% by mass or less, or may be 0.00001% by mass or more and less than 0.1% by mass, or may be 0.001% by mass or more and 1% by mass or less, or may be 0.001% by mass or more and less than 0.5% by mass or less, or may be 0.001% by mass or more and less than 0.1% by mass.

[0074] When the pH of the oil-in-water emulsion composition is greater than 5.5 and less than 6.0, the mass ratio of the polysaccharide content to the solid particle content in the oil-in-water emulsion composition may be greater than 0 and less than 1.0, greater than 0 and less than 0.50, greater than 0 and less than 0.10, greater than 0 and less than 0.042, 0.001 or more and 1.0 or less, 0.001 or more and 0.50 or less, 0.001 or more and 0.10 or less, or 0.001 or more and less than 0.042.

[0075] When the pH of the oil-in-water emulsion composition is greater than 5.5 and less than 6.0, the mass ratio of the polysaccharide content to the fat / oil content in the oil-in-water emulsion composition may be greater than 0 and less than 1.0, greater than 0 and less than 0.50, greater than 0 and less than 0.10, greater than 0 and less than 0.040, 0.001 or more and 1.0 or less, 0.001 or more and 0.50 or less, 0.001 or more and 0.10 or less, or 0.001 or more and less than 0.040.

[0076] In yet another embodiment, when the pH of the oil-in-water emulsion composition is 4.0 to 5.5, the content of the polysaccharide may be 0.04% by mass or more and 0.06% by mass or less, or may be greater than 0% by mass and 5% by mass or less, or may be greater than 0% by mass and 1% by mass or less, or may be greater than 0% by mass and 0.5% by mass or less, or may be greater than 0% by mass and less than 0.1% by mass, or may be 0.00001% by mass or more and 1% by mass or less, or may be 0.00001% by mass or more and 0.5% by mass or less, or may be 0.00001% by mass or more and less than 0.1% by mass, or may be 0.001% by mass or more and 1% by mass or less, or may be 0.001% by mass or more and less than 0.5% by mass or less, or may be 0.001% by mass or more and less than 0.1% by mass.

[0077] When the pH of the oil-in-water emulsion composition is 4.0 to 5.5, the mass ratio of the polysaccharide content to the solid particle content in the oil-in-water emulsion composition may be greater than 0 and less than 1.0, greater than 0 and less than 0.50, greater than 0 and less than 0.10, greater than 0 and less than 0.042, 0.001 or more and 1.0 or less, 0.001 or more and 0.50 or less, 0.001 or more and 0.10 or less, or 0.001 or more and less than 0.042.

[0078] When the pH of the oil-in-water emulsion composition is 4.0 to 5.5, the mass ratio of the polysaccharide content to the fat / oil content in the oil-in-water emulsion composition may be greater than 0 and less than 1.0, greater than 0 and less than 0.50, greater than 0 and less than 0.10, greater than 0 and less than 0.040, 0.001 or more and less than 1.0, 0.001 or more and less than 0.50, 0.001 or more and less than 0.10, or 0.001 or more and less than 0.040.

[0079] In one embodiment, the bond (reaction or interaction) between the polysaccharide and the solid particles (which may include solid particles adsorbed to the oil-water interface) in the oil-in-water emulsion composition may include, for example, hydrophobic interaction, intermolecular force interaction, hydrogen bonding, electrostatic interaction, etc. Among these, one or more types of bond selected from hydrophobic interaction, hydrogen bonding, and electrostatic interaction are preferred. From the viewpoint of inhibition of electrostatic interaction by salt, hydrophobic interaction and / or hydrogen bonding are more preferred. Furthermore, when the solid particles are hydrophobic proteins, hydrophobic interaction is more preferred.

[0080] In one embodiment, the method for analyzing the polysaccharides contained in the oil-in-water emulsion composition is not particularly limited, and the analysis can be carried out, for example, by the following steps (1) to (3): (1) The oil-in-water emulsion composition is centrifuged, and the supernatant and sediment (e.g., solid particles to which polysaccharides are adsorbed) are collected and analyzed. (2) The polysaccharides are desorbed from the sediment obtained in (1) by various methods (e.g., adding salt, adjusting pH, washing with a desired solvent such as ethanol), to obtain a polysaccharide extract. (3) The supernatant obtained in (1) and the polysaccharide extract obtained in (2) can be identified by a method known per se, such as GPC, LC / MS, LC / MS / MS, GC / MS, GC / MS / MS, or NMR.

[0081] (Other Components) In one embodiment, the oil-in-water emulsion composition according to the second aspect may further contain colorants, antioxidants, sweeteners, stabilizers, dairy components, flavorings, colorants, salts, organic acids, etc., within the scope of not impairing the effects of the present invention. The same components as those contained in the oil-in-water emulsion composition according to the first aspect of the present invention can be used, and the same is also true for preferred aspects.

[0082] In one embodiment, the oil-in-water emulsion composition has the configuration of the second aspect, and thus has high heat resistance, for example, even when it does not contain an amphiphilic substance such as a sucrose fatty acid ester, and even when it is subjected to, for example, retort treatment (at 121°C for 30 minutes), separation of the oil phase and the formation of aggregates of oil droplets and solid particles do not occur. That is, one embodiment of the present invention is an oil-in-water emulsion composition comprising solid particles, water, oils and fats, and polysaccharides, wherein the solid particles comprise a protein derived from a grass plant, and which does not contain an amphiphilic substance. The content of the amphiphilic substance in the oil-in-water emulsion composition may be less than 0.00001% by mass, or even 0% by mass, based on the mass of the oil-in-water emulsion composition. The ratio of the mass of the amphiphilic substance to the mass of the solid particles may be less than 0.00001% by mass, or even 0% by mass.

[0083] <Production of the Oil-in-Water Emulsion Composition of the Second Aspect> In one embodiment, the oil-in-water emulsion composition of the second aspect can be produced by the same method as the oil-in-water emulsion composition of the first aspect of the present invention, and the same applies to preferred aspects. The addition of a polysaccharide in the second aspect can be carried out in place of the alkali metal salt in the first aspect. Furthermore, while an example in which an alkali metal salt is contained in the aqueous phase component has been exemplified in the production method of the oil-in-water emulsion composition of the first aspect, in the production method of the oil-in-water emulsion composition of the second aspect, the polysaccharide can also be added after the emulsion is produced. To avoid inhibiting the adsorption of solid particles to the water-oil interface, it is preferable to add the polysaccharide after the oil-in-water emulsion composition is formed. The polysaccharide is preferably added using an aqueous solution in which the polysaccharide has been dissolved in advance. This allows mixing in a uniformly dispersed state, making it possible to form an oil-in-water emulsion composition with excellent heat resistance. The polysaccharide may be added by adopting a step of mixing the oil-in-water emulsion composition (food production intermediate) with a polysaccharide-containing intermediate during food production / processing.

[0084] <Third Aspect> In this specification, among the oil-in-water emulsion compositions, the oil-in-water emulsion composition is referred to as the third aspect, which comprises solid particles, water, and an oil and fat, has a thermal history of being heated at a temperature exceeding 95°C, the solid particles are composed of a protein derived from a grass family plant, and the oil and fat form oil droplets whose diameter is maintained at 0.2 µm or more and 1 mm or less.

[0085] (Solid Particles, Oil Phase Component, and Aqueous Phase Component) The oil phase component and the aqueous phase component in the third aspect of the present invention may be the same as the oil phase component and the aqueous phase component contained in the oil-in-water emulsion composition according to the first or second aspect of the present invention, respectively, and the same applies to preferred aspects. Furthermore, the solid particles comprising a grass plant-derived protein in the third aspect may be the same as the solid particles comprising a grass plant-derived protein in the first or second aspect, and the same applies to preferred aspects.

[0086] In conventional oil-in-water emulsion compositions, when the composition has a thermal history of being heated at a temperature exceeding 95°C, the oil droplets in the composition aggregate or are destroyed, resulting in separation of the oil, making it impossible to maintain an oil droplet diameter of 0.2 μm or more and 1 mm or less. The oil-in-water emulsion composition according to the third aspect surprisingly has the property of maintaining an oil droplet diameter of 0.2 μm or more and 1 mm or less, even when the composition has a thermal history of being heated at a temperature exceeding 95°C. The third aspect of the present invention is an invention defined by this property. The means for achieving the properties of the oil-in-water emulsion composition according to the third aspect are not particularly limited, and, for example, some or all of the configurations employed in the first and / or second aspects can be applied. Therefore, the oil-in-water emulsion composition according to the third aspect can be produced in accordance with the method for producing the oil-in-water emulsion composition according to the first or second aspect.

[0087] (Structure of oil-in-water emulsion composition) The oil-in-water emulsion composition in the first, second, and third aspects of the present invention has an emulsion structure in which solid particles are present at the interface between the oil phase component and the aqueous phase component. By having such a structure, it is possible to obtain an oil-in-water emulsion composition in which the particle size is controlled even before and after heating and which has high heat resistance and temperature drop resistance. The structure in which solid particles are present at the interface between the oil phase component and the aqueous phase component refers to a structure in which solid particles are adsorbed to the interface between the oil phase component and the aqueous phase component. This makes it possible to emulsify the oil phase in the aqueous phase, forming a so-called Pickering emulsion. Specifically, this refers to a structure in which at least a portion of the solid particles are adsorbed to the surface of the oil phase emulsified in the aqueous phase.

[0088] The presence of solid particles at the interface between the oil phase component and the aqueous phase component can be confirmed by cross-sectional observation of the oil-in-water emulsion composition using a cryo-scanning electron microscope (cryo-SEM) or the like. The method for observing the cross-section is not particularly limited as long as it is a commonly used method. For example, the oil-in-water emulsion composition can be rapidly frozen using a rapid freezing method such as the metal contact method, and then the frozen oil-in-water emulsion composition is cut with a cryomicrotome using a diamond knife for optical microscopes to prepare a sample, and the cross-section of the sample can be observed using a cryo-SEM. Furthermore, the oil-in-water emulsion compositions of the first, second, and third aspects have the above structure, and therefore have emulsion stability that can withstand longer storage periods. Furthermore, because they have the above structure, it is possible to further suppress the progression of oxidative degradation and hydrolysis of oils and fats, which can lead to the generation of peculiar odors during emulsification and during storage of the emulsified composition after emulsification.

[0089] <Uses of the Oil-in-Water Emulsion Composition> The oil-in-water emulsion composition according to the first, second, and / or third aspect of the present invention can be used in pharmaceuticals, cosmetics, foods, feeds, diagnostic agents, carriers for drug delivery systems (DDS), detergents, coating agents, surface treatment agents, toiletries, and personal care products. For example, it can be used for oral ingestion or transdermal absorption. It can also be used as a production intermediate thereof. That is, the oil-in-water emulsion composition of the present invention may be a food-grade oil-in-water emulsion composition, a cosmetic-grade oil-in-water emulsion composition, or a pharmaceutical-grade oil-in-water emulsion composition. It may be a food-grade, cosmetic-grade, or pharmaceutical-grade oil-in-water emulsion composition, or a food, cosmetic, or pharmaceutical containing the oil-in-water emulsion composition. The oil-in-water emulsion composition itself can also be provided as a food, cosmetic, or pharmaceutical (a pharmaceutical containing an active pharmaceutical ingredient). In one embodiment, any of the oil-in-water emulsion composition, the food-grade oil-in-water emulsion composition, or the food-grade oil-in-water emulsion composition can be used in the production of food. By appropriately combining these compositions with other raw materials for food production and / or preparations for food production (intermediates), and mixing and / or processing (including high-temperature treatment such as sterilization), desired foods can be produced, and foods containing the oil-in-water emulsion composition can be provided. By including the oil-in-water emulsion composition of the present invention, it is possible to achieve a taste quality with a favorable texture and flavor and long-term storage stability. Specific examples of foods are described below. In another embodiment, any of the oil-in-water emulsion composition, the oil-in-water emulsion composition for cosmetics, or the cosmetic-grade oil-in-water emulsion composition can be used in the production of cosmetics. By appropriately combining these compositions with other raw materials for cosmetic production and / or preparations for cosmetic production (including intermediates and / or active ingredients for cosmetics), and mixing and / or processing, desired cosmetics can be produced, and cosmetics containing the oil-in-water emulsion composition can be provided. By including the oil-in-water emulsion composition of the present invention, cosmetics with excellent usability, such as a favorable texture and ease of application, can be produced. In another embodiment, any of the oil-in-water emulsion composition, pharmaceutical grade oil-in-water emulsion composition, or pharmaceutical grade oil-in-water emulsion composition can be used in the manufacture of pharmaceuticals.By appropriately combining these compositions with other raw materials for pharmaceutical production and / or preparations for pharmaceutical production (intermediates and / or active pharmaceutical ingredients, etc.), mixing and / or processing (including high-temperature treatment such as sterilization) the desired pharmaceutical can be produced, and pharmaceuticals containing the oil-in-water emulsion composition can be provided. By including the oil-in-water emulsion composition of the present invention, pharmaceuticals with excellent usability and favorable texture, feel, or flavor (including masking of bitterness) can be obtained.

[0090] When used for oral ingestion, there are no limitations on the product, use, properties, etc., as long as it is taken orally. Specific uses include foods and beverages such as beverages, liquid foods, cream foods, and animal-derived food substitutes including milk substitutes; retort nutritional supplements; functional foods such as liquid diets; oral vaccines; processed wheat flour products such as bread and noodles; processed oils and fats such as fat spreads and flower pastes; various sauces and soups such as curry, coffee creamer, mayonnaise, dressings, mousse, pasta sauce, stew, demi-glace sauce, white sauce, or tomato sauce; retort foods and compound seasonings such as Chinese food bases and rice bowl bases; yogurts, These include sweets and desserts such as cheese, ice cream, cream, caramel, candy, chewing gum, chocolate, cookies / biscuits, cakes, pies, snacks, crackers, Japanese sweets, rice snacks, bean snacks, jelly, pudding, etc.; processed livestock products such as hamburgers, meatballs, and seasoned canned meat; frozen foods; refrigerated foods; cooked and semi-cooked foods such as packaged and store-bought prepared foods; ready-to-eat foods such as instant noodles, cup noodles, instant soups and stews; fortified foods; foods and beverages such as liquid diets, high-calorie foods, and infant nutritional products; and tube feeding preparations.

[0091] In particular, foods such as beverages and liquid foods are preferred. Examples of such beverages include milk beverages, soup beverages, coffee beverages, cocoa beverages, tea beverages (black tea, green tea, Chinese tea, etc.), bean / grain beverages, and acidic beverages. Among these, milk beverages, coffee beverages, and tea beverages are preferred. A milk substitute refers to an emulsified composition that can replace animal-derived milk such as cow's milk in terms of taste, flavor, and physical properties. It can also be used as a production intermediate for foods such as yogurt and ice cream. Examples of such physical properties include the particle size distribution of oil droplets in the composition, viscosity, pH, emulsion stability, and appearance. Furthermore, the food-grade oil-in-water emulsion composition and / or food-grade oil-in-water emulsion composition of the present invention, which are one embodiment of the present invention, can be suitably used for packaged beverages such as canned beverages, PET bottled beverages, paper-packaged beverages, and bottled beverages. The pH of a product (food, cosmetic, pharmaceutical, or intermediate for producing them) containing the oil-in-water emulsion composition of the first, second, and / or third aspect may be adjusted to a suitable range depending on the intended application and product. For example, when applied to food, the pH may be edible or drinkable, but the lower limit is usually greater than pH 1, preferably pH 3 or higher, more preferably pH 4 or higher, even more preferably pH 5 or higher, particularly preferably pH 5.5 or higher, especially preferably pH 6 or higher, and most preferably pH 6.5 or higher. The upper limit is usually pH 13 or lower, preferably pH 10 or lower, more preferably pH 9.5 or lower, even more preferably pH 9.0 or lower, especially preferably pH 8.5 or lower, especially preferably pH 8.0 or lower, and most preferably pH 7.5 or lower. By setting the pH in the above preferred range, better emulsion stability can be maintained. By setting the pH in the above range, the size of the dispersed phase (oil droplet diameter) can be suitably maintained, making it possible to maintain a good texture when eaten.

[0092] The grass plant-derived proteins, oils and fats, alkali metal salts, and polysaccharides disclosed in the present specification are known per se and can be produced or obtained by producing them according to known methods or by purchasing commercially available products.

[0093] The present invention will be described in more detail below with reference to examples. However, it goes without saying that the scope of the present invention is not limited to the embodiments shown in the following examples. In the examples, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

[0094] The methods for measuring physical properties in the examples are as follows. <Measurement of particle size distribution of protein or oil phase (oil droplets) which is the internal phase of emulsion> The diameter of the oil droplets which are the internal phase of the protein or emulsion composition was measured by a batch measurement method using a laser diffraction / scattering particle size distribution analyzer LA-950 (manufactured by HORIBA). The analysis was performed with the refractive index of the substance to be measured set to 1.60. The average particle size and median diameter of the protein were calculated by analysis on a number basis and a volume basis. The average particle size and median diameter of the oil droplets which are the internal phase of the emulsion composition were calculated by analysis on a number basis and a volume basis.

[0095] <Measurement of pH> Measurement was carried out using a LAQUA PH / ION METER F-72 manufactured by Horiba Ltd. or a LAQUAact D-71 manufactured by Horiba Ltd.

[0096] <Microscopic Observation> The emulsion was observed under a microscope using a polarizing microscope manufactured by Olympus Corporation.

[0097] <Analysis of Fats and Oils> Analytical tests for the acid value, saponification value, and slip melting point of fats and oils were carried out according to the method described in Standard Methods for the Analysis of Fats and Oils (compiled by Japan Oil Chemists' Society).

[0098] <Amino Acid Analysis> Samples for free amino acid analysis were prepared as follows: 10 mg of sample was weighed. 1 ml of ultrapure water was added to 10 mg of sample, and then ultrasonic waves were applied. 300 μL of the water-soluble fraction was subjected to ultrafiltration (MWCO: 10,000). The membrane-permeate fraction was used as a sample for free amino acid analysis.

[0099] Samples for hydrolysis amino acid analysis were prepared as follows: 5 mg of sample was dispensed into a test tube. Hydrolysis was performed for 1 hour at 150°C under a 6N hydrochloric acid atmosphere. After cooling, the hydrochloric acid was removed using a centrifugal evaporator, and the residue was redissolved in 200 μL of ultrapure water and centrifuged. 100 μL of the water-soluble fraction was then diluted 10-fold with 900 μL of ultrapure water. The mixture was then filtered through a 0.45 μm filter. The resulting filtrate was used as the sample for hydrolysis amino acid analysis.

[0100] Free amino acid analysis and hydrolyzed amino acid analysis were performed using the following equipment and under the following measurement conditions. The free amino acid analysis value was then subtracted from the hydrolyzed amino acid analysis value to calculate the BSA-equivalent protein content and free amino acid content.

[0101] Equipment: Hitachi Amino Acid Analyzer L-8900 Measurement conditions: Biological amino acid separation conditions - ninhydrin colorimetric method Standard: PF (Wako amino acid mixture AN type 0.8 ml + B type 0.8 ml → 10 ml) Asparagine, glutamine, tryptophan aqueous solution injection volume: 10 μL Quantitative calculation: Calculated using a single calibration curve from the peak area

[0102] <Quantitative analysis of phospholipids> The following analysis items were performed on samples by nuclear magnetic resonance spectroscopy at the Japan Food Research Center, a general incorporated foundation. The acyl groups of phospholipid molecular species were quantified as stearic acid. Analyzed items: phosphatidylcholine, phosphatidylinositol, phosphatidylserine, lysophosphatidylcholine, phosphatidylethanolamine, N-acylphosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid

[0103] <Raw Materials> The raw materials used and their physical properties are as follows: - Hardened coconut oil: solid at 25°C, acid value 0.47, saponification value 255, slip melting point 28.8°C - Solid particles: grass plant-derived protein / rice-derived protein [Oryza Protein-P70 manufactured by Oryza Oil & Fat Chemical Co., Ltd.; protein obtained from the seeds of grass (Oryza sative Linne)]. Hereinafter, this may be abbreviated as P70. The amino acid score of P70 is 56. The contact angle of water with P70 is 69°. - Water: demineralized water or pH buffer solution - Polysaccharide: xanthan gum (Mitsubishi Chemical, Soaxan XG400)

[0104] The emulsion composition according to the first aspect of the present invention is described below. <Preparation of Aqueous Protein Dispersions> A protein derived from a grass plant / rice (Oryza Protein-P70, manufactured by Oryza Oil & Fat Chemical Co., Ltd.; a protein obtained from the seeds of grasses (Oryza sative Linne)) as solid particles (protein) and demineralized water were mixed to a total of 100 parts, and the mixture was subjected to the steps described below to prepare aqueous protein dispersions. The blending amounts (parts) of each component used in each preparation example are shown in Table 1. The pH and particle size distribution measurements of the prepared aqueous protein dispersions are also shown in Table 1. When preparing each aqueous protein dispersion, the protein used was previously classified using a sieve with a mesh size of 45 μm. Each prepared aqueous protein dispersion was stored in a refrigerator at 4°C. Oryza Protein-P70 (manufactured by Oryza Oil & Fat Chemical Co., Ltd.) and Ryoto Sugar Ester S-1670 (manufactured by Mitsubishi Chemical Corporation) will be abbreviated as P70 and S-1670, respectively. The physical properties of each raw material are as follows: P70: Amino acid score = 56 S-1670: Monoester content = 78% by mass, HLB = 16

[0105] Preparation Example 1-1: 95 parts of pH 9 buffer solution (10 mM sodium bicarbonate / sodium carbonate) and 5 parts of P70 were dispensed into a container and mixed. This mixture was treated for 10 passes at 245 MPa using a Starburst Lab (Sugino Machine Corporation, using an oblique impingement chamber) to obtain an aqueous protein dispersion A1. The pH 9 buffer solution was prepared by previously mixing 10 mM sodium bicarbonate and 10 mM sodium carbonate to adjust the pH to 9.

[0106] Preparation Example 2-1 A protein aqueous dispersion A2 was obtained in the same manner as in Preparation Example 1-1, except that a pH 11 buffer solution (10 mM aqueous sodium carbonate solution) was used.

[0107] Preparation Example 3-1 A protein aqueous dispersion A3 was obtained in the same manner as in Preparation Example 1-1, except that a pH 9 buffer solution (100 mM sodium bicarbonate / sodium carbonate) was used.

[0108] (Preparation Example 4-1) An aqueous solution to which a sucrose fatty acid ester (S-1670) had been added in advance and P70 were dispensed into a container and mixed. This mixture was treated with a Starburst Lab in the same manner as in Preparation Example 1-1 to obtain a protein aqueous dispersion A4. The aqueous solution of sucrose fatty acid ester was prepared by mixing demineralized water and sucrose fatty acid ester and dissolving the mixture by heating.

[0109] Preparation Example 5-1 A protein aqueous dispersion A5 was obtained in the same manner as in Preparation Example 1-1, except that demineralized water and P70 were used.

[0110] (Preparation Example 6-1) A protein aqueous dispersion A6 was obtained in the same manner as in Preparation Example 1-1, except that the treatment using Starburst Lab (Sugino Machine Corporation, using an oblique collision chamber) was not performed and untreated P70 (P70 that had not been subjected to classification using a sieve with 45 μm openings) was used.

[0111] Preparation Example 7-1 A protein aqueous dispersion A7 was obtained in the same manner as in Preparation Example 6-1, except that demineralized water was used instead of the pH 9 buffer solution.

[0112]

[0113] <Preparation of oil-in-water emulsion composition> The blending amount (parts by mass) of each component used in the examples and comparative examples is shown in Table 2. When calculating the concentration of the alkali metal salt in the emulsion composition, the specific gravity of the vegetable oil (hardened palm oil) was set to 0.92, and the specific gravity of the other oils was set to 1. The mixer used was a T.K. Robomix (T.K. Homomixer MARK II 2.5 type as the mixing part) manufactured by PRIMIX, or a Homomixer MAR K II (2.5 type). Hereinafter, these mixers will be referred to as homomixers.

[0114] Example 1-1 Aqueous protein dispersion A1 and hardened coconut oil heated to 60°C were dispensed into containers in the mass ratios shown in Table 2. These were mixed at 60°C and stirred at 10,000 rpm at 60°C for 1 minute using a homomixer, and then stirred at 3,000 rpm for 20 minutes to obtain oil-in-water emulsion composition A1.

[0115] Example 2-1 An oil-in-water emulsion composition A2 was obtained in the same manner as in Example 1-1, except that the aqueous protein dispersion A2 was used.

[0116] Example 3-1 An oil-in-water emulsion composition A3 was obtained in the same manner as in Example 1-1, except that the aqueous protein dispersion A3 was used.

[0117] Comparative Example 1-1 An oil-in-water emulsion composition A4 was obtained in the same manner as in Example 1-1, except that the aqueous protein dispersion A4 was used.

[0118] Comparative Example 2-1 An oil-in-water emulsion composition A5 was obtained in the same manner as in Example 1-1, except that the aqueous protein dispersion A5 was used.

[0119] Example 4-1 An oil-in-water emulsion composition A6 was obtained in the same manner as in Example 1-1, except that the aqueous protein dispersion A6 was used.

[0120] Comparative Example 3-1 An oil-in-water emulsion composition A7 was obtained in the same manner as in Example 1-1, except that the aqueous protein dispersion A7 was used.

[0121]

[0122] <Evaluation of Temperature-Changing Stability of Oil-in-Water Emulsion Compositions> Oil-in-water emulsion compositions A1, A2, A3, A6, A4, A5, and A7 according to Examples 1-1, 2-1, 3-1, and 4-1 and Comparative Examples 1-1, 2-1, and 3-1, emulsified at 60°C, were each placed in a container, and the container was immersed in a water bath for 30 minutes or more to lower the temperature to 25°C. The container was then inverted, and the fluidity and presence or absence of aggregation of the oil-in-water emulsion composition before and after the temperature drop were visually confirmed, and evaluated according to the following criteria. In addition, the pH of each oil-in-water emulsion composition after the temperature drop was measured at room temperature. These results are shown in Table 3. ◯: No aggregates in the emulsion and good fluidity. △: A small amount of aggregates were generated in the emulsion, but good fluidity. ×: Aggregates were generated in the emulsion and the fluidity was poor.

[0123]

[0124] As is clear from the results shown in Table 3, the emulsion composition according to the first aspect of the present invention was free from or only slightly aggregated even after cooling, and was flowable, and was able to maintain a stable emulsified state even in a temperature range where the oil or fat, which is the discontinuous phase of the emulsion, changes from a liquid state to a solid state.

[0125] <Evaluation of Heat Resistance of Oil-in-Water Emulsion Compositions> (Evaluation 1) Appearance Observation 20 g of each of the oil-in-water emulsion compositions A1, A2, A3, A6, A4, A5, and A7 according to Examples 1-1, 2-1, 3-1, and 4-1 and Comparative Examples 1-1, 2-1, and 3-1, which had been allowed to cool to room temperature, was dispensed into a transparent container, and the appearance was observed before or after heating (treatment at 95°C for 10 minutes, treatment at 121°C for 30 minutes). When heat treatment was performed at 121°C for 30 minutes, the opening of the container into which each oil-in-water emulsion composition had been dispensed was covered with aluminum foil, and the heat treatment was performed in an autoclave (Hirayama Seisakusho, Hiclave HG-80) at 121°C, 0.12 MPa, and 30 minutes. After heating in the autoclave, the internal temperature of the apparatus was confirmed to be 80°C or lower, and then the container was removed. Before being allowed to cool to room temperature, the presence or absence of oil phase separation and aggregates was visually confirmed from the side of the container. When performing heat treatment at 95°C for 10 minutes, the container into which each oil-in-water emulsion composition had been dispensed was immersed in a water bath to perform treatment at 95°C for 10 minutes, and then the presence or absence of oil phase separation and aggregates was visually confirmed from the side of the container before being allowed to cool to room temperature. Note that for the oil-in-water emulsion compositions A6 and A7 according to Example 4-1 and Comparative Example 3-1, 20 g of evaluation samples were dispensed, avoiding the slight aggregates that occurred when the temperature was lowered to 25°C. The results of evaluation based on the following criteria are shown in Table 3. ○: No oil phase separation, no aggregation △: No oil phase separation, slight aggregation ×: No oil phase separation, aggregation XX: Oil phase separation, aggregation

[0126] No oil phase separation was observed in any of the emulsion compositions according to the Examples. Although emulsion compositions A4 and A5 according to the Comparative Examples did not show oil phase separation after heat treatment at 121°C for 30 minutes, severe aggregation and sedimentation to the bottom of the container were observed. On the other hand, emulsion compositions A1 and A2 according to the Examples did not show oil phase separation, and no aggregation was observed. Although emulsion composition A3 according to the Example did not show oil phase separation, only slight aggregation was observed. Even in the oil-in-water emulsion composition A6 according to Example 4-1, in which the size of the solid particles (grass plant-derived proteins) was relatively large, there was no significant change in appearance of the evaluation sample after heat treatment at 121°C for 30 minutes compared to the evaluation sample before heat treatment, and good stability was confirmed. On the other hand, in the oil-in-water emulsion composition A7 according to Comparative Example 3-1, oil phase separation was observed after heat treatment, and aggregation was observed at the bottom of the container compared to the evaluation sample before heat treatment, indicating low emulsion stability. From this, it can be said that the emulsion composition of the first aspect of the present invention is a stable emulsion composition having excellent heat resistance.

[0127] (Evaluation 2) Measurement of particle size distribution of samples before and after heating The samples in (Evaluation 1) above, before and after heating at 121°C for 30 minutes, were subjected to pH measurement and particle size distribution measurement. These results are shown in Table 4. The rate of change in oil droplet size before and after heating at 121°C was calculated and shown in Table 4. Graphs analyzing the particle size distribution measurement results before and after heating on a volume basis are shown in Figures 1 to 5. Note that the samples heated at 121°C were allowed to cool to below room temperature and then used for measurements at room temperature.

[0128]

[0129] Here, attention is focused on the rate of change in median diameter before and after heating. The rate of change in median diameter of emulsion compositions A1, A2, and A3 according to Examples 1-1, 2-1, and 3-1 is suppressed to be lower than that of emulsion compositions A4 and A5 according to Comparative Examples 1-1 and 2-1. From these results, it can be seen that the emulsion composition of the present invention is a highly heat-resistant emulsion composition that has high stability against high-temperature heating and against cooling after high-temperature heating (crystallization of the internal phase oil / fat due to temperature decrease).

[0130] (Evaluation 3) Microscopic Observation of Samples Before and After Heating Microscopic observation was performed on the samples before and after heating at 121°C for 30 minutes as described in (Evaluation 1) above. These results are shown in Figures 6 and 7. Note that the samples heated at 121°C were allowed to cool to below room temperature, diluted with demineralized water, and observed at room temperature. As is clear from Figures 6 and 7, the emulsion composition of the present invention maintains a structure in which solid particles are adsorbed at the water-oil interface before and after heating.

[0131] <Beverage Production Example> Oil-in-water emulsion composition A2 (oil concentration relative to the total mass of the composition: 5%) was heat-sterilized at 121°C for 30 minutes, allowed to cool to room temperature, and then stored at 4°C. The composition was then returned to room temperature and added to various beverages and mixed. The oil concentration in the composition after mixing was 1% relative to the total mass of the composition. Emulsion composition A2, which had been heat-sterilized at 121°C for 30 minutes, was added to each beverage and mixed. The pH and particle size distribution at room temperature were measured (analysis conditions: volume basis) for the mixtures obtained by adding and mixing each of the beverages to which emulsion composition A2 had been added. The results are shown in Table 5. The particle size distributions before and after mixing each beverage with emulsion composition A2 are also shown in Figures 6 to 9. The beverages used for mixing with the oil-in-water emulsion composition were prepared as follows. Black tea was prepared by adding one bag of Ajinomoto AGF Professional Instant Tea to 1,000 g of hot water and mixing. The coffee was prepared by mixing 1.5 parts of Nescafe Gold Blend (Nestlé Japan Ltd.), 0.05 parts of baking soda, and 98.45 parts of hot water, and then filtering the mixture to remove insoluble components.

[0132]

[0133] As is clear from Table 5, the emulsion composition according to the first aspect of the present invention was found to maintain emulsion stability that allows it to be mixed with commercially available instant beverages, in addition to being produced as a beverage or beverage intermediate. Thus, it was shown that the emulsion composition of the present invention can be used to produce beverages, and that a beverage composition containing the emulsion composition can be produced by mixing the emulsion composition with a beverage intermediate, and this beverage composition can be provided as a food product.

[0134] The emulsion composition according to the second aspect of the present invention will be described below.

[0135] <Preparation of aqueous protein dispersion> The blending amount (parts by mass) of each component used in the preparation examples is shown in Table 6. (Preparation Example 1-2) 95 parts of demineralized water and 5 parts of P70 were dispensed into a container and mixed. This mixture was treated for 10 passes at 245 MPa using a Starburst Lab (Sugino Machine Corporation, oblique impingement chamber) to obtain aqueous protein dispersion 1-2.

[0136] (Preparation Example 2-2) An aqueous solution to which sucrose fatty acid ester (S-1670) had been added in advance and P70 were mixed in a container in the amounts shown in Table 6. This mixture was treated 10 times at 245 MPa using a Starburst Lab (Sugino Machine Corporation, oblique impingement chamber) to obtain a protein aqueous dispersion 2-2. The aqueous solution of sucrose fatty acid ester was prepared by mixing demineralized water and sucrose fatty acid ester and dissolving the mixture by heating.

[0137]

[0138] <Preparation of oil-in-water emulsion composition> The blending amount (parts by mass) of each component used in the examples and comparative examples is shown in Table 7. The mixer used was a T.K. Robomix manufactured by PRIMIX (T.K. Homomixer MARK II 2.5 type as the mixing part). Hereinafter, this mixer will be referred to as a homomixer.

[0139] (Preparation Example 3-2) Aqueous protein dispersion B1 and hardened coconut oil heated to 60°C were dispensed into containers in the mass ratios shown in Table 7. These were mixed at 60°C and stirred at 10,000 rpm at 60°C using a homomixer for 1 minute, and then stirred at 3,000 rpm for 20 minutes, to obtain oil-in-water emulsion composition B1.

[0140] (Preparation Example 4-2) Protein aqueous dispersion B2 and hardened coconut oil heated to 60°C were dispensed into containers in the mass ratios shown in Table 7. These were mixed at 60°C and stirred at 10,000 rpm at 60°C using a homomixer for 1 minute, and then stirred at 3,000 rpm for 20 minutes, to obtain oil-in-water emulsion composition B2.

[0141]

[0142] <Preparation of oil-in-water emulsion composition by mixing oil-in-water emulsion composition with a modifying aid> Table 8 shows the blending amount (parts by mass) of each component used in the examples and comparative examples.

[0143] Example 1-2 Oil-in-water emulsion composition B1, which had been allowed to cool to room temperature, was mixed with a xanthan gum solution prepared in advance so as to obtain the blending ratio shown in Table 8, thereby obtaining oil-in-water emulsion composition B1-1.

[0144] Example 2-2 Oil-in-water emulsion composition B1, which had been allowed to cool to room temperature, was mixed with a xanthan gum solution prepared in advance so as to obtain the blending ratio shown in Table 8, thereby obtaining oil-in-water emulsion composition B1-2.

[0145] Example 3-2 Oil-in-water emulsion composition B1, which had been allowed to cool to room temperature, was mixed with a xanthan gum solution prepared in advance so as to obtain the blending ratio shown in Table 8, thereby obtaining oil-in-water emulsion composition B1-3.

[0146] Example 5-2 Oil-in-water emulsion composition B1, which had been allowed to cool to room temperature, was mixed with a xanthan gum solution prepared in advance so as to obtain the blending ratio shown in Table 8, thereby obtaining oil-in-water emulsion composition B1-5.

[0147] Example 6-2 Oil-in-water emulsion composition B1, which had been allowed to cool to room temperature, was mixed with a xanthan gum solution prepared in advance so as to obtain the blending ratio shown in Table 8, thereby obtaining oil-in-water emulsion composition B1-6.

[0148] Comparative Example 1-2 Oil-in-water emulsion composition B1, which had been allowed to cool to room temperature, was mixed with demineralized water so as to obtain the blending ratio shown in Table 8, thereby obtaining oil-in-water emulsion composition B1-7.

[0149] Comparative Example 2-2 Oil-in-water emulsion composition B2 was allowed to cool to room temperature and designated as oil-in-water emulsion composition B2-1.

[0150] Comparative Example 3-2 Oil-in-water emulsion composition B1, which had been allowed to cool to room temperature, demineralized water, and a pH 6 buffer solution were mixed together to obtain the blending ratio shown in Table 8, thereby obtaining oil-in-water emulsion composition B1-8.

[0151] Comparative Example 4-2 Oil-in-water emulsion composition B1, which had been allowed to cool to room temperature, demineralized water, and a pH 5 buffer solution were mixed together to obtain the blending ratio shown in Table 8, thereby obtaining oil-in-water emulsion composition B1-9.

[0152]

[0153] <Evaluation of heat resistance and temperature-lowering stability of oil-in-water emulsion compositions> (Evaluation 1) Observation of appearance before and after heat treatment. 20 g of each of the oil-in-water emulsion compositions B1-1 to B1-3, B1-5, B1-6, B1-7, B2-1, B1-8, and B1-9 according to Examples 1-2 to 3-2, 5-2, and 6-2 and Comparative Examples 1-2 to 4-2, which had been allowed to cool to room temperature, was dispensed into a transparent container, and the appearance was observed before or after heating (95°C, 10 minutes treatment, 121°C, 30 minutes treatment). When heat treatment was performed at 121°C for 30 minutes, the opening of the container into which each oil-in-water emulsion composition had been dispensed was covered with aluminum foil and the heat treatment was performed at 121°C for 30 minutes in an autoclave. After heating in the autoclave, it was confirmed that the temperature inside the apparatus was 80°C or less, and then the container was removed. Before being allowed to cool to room temperature, the presence or absence of oil phase separation and aggregates was visually confirmed from the side of the container. When performing heat treatment at 95°C for 10 minutes, the container into which each oil-in-water emulsion composition had been dispensed was immersed in a water bath to perform treatment at 95°C for 10 minutes, and then the presence or absence of oil phase separation and aggregates was visually confirmed from the side of the container before being allowed to cool to room temperature. The results, evaluated according to the following criteria, are shown in Table 9. ⊚: No oil phase separation, no aggregates ◯: No oil phase separation, slight aggregates △: No oil phase separation, aggregates present ×: oil phase separation present

[0154]

[0155] Although no oil-in-water emulsion composition showed oil phase separation, the oil-in-water emulsion compositions B1-7, B2-1, B1-8, and B1-9 according to Comparative Examples 1-2 to 4-2 showed severe aggregation after heat treatment at 121°C for 30 minutes, and sedimentation to the bottom of the container was observed. On the other hand, the emulsion compositions B1-1 to B1-3, and B1-5 according to Examples 1-2 to 3-2 and 5-2 showed no oil phase separation and no aggregation was observed. The emulsion composition B1-6 according to Example 6-2 showed no oil phase separation, but very slight aggregation was observed. From this, it can be said that the emulsion composition of the present embodiment is a stable emulsion composition having excellent heat resistance.

[0156] (Evaluation 2) Evaluation of temperature-lowering stability of oil-in-water emulsion compositions Containers containing the oil-in-water emulsion compositions of Examples 1-2 to 3-2, 5-2, and 6-2 and Comparative Examples 1-2 to 4-2, which had been heated at 121°C in the heat resistance test described above, were immersed in a water bath for 30 minutes or more to lower the temperature to 25°C. The containers were then inverted, and the fluidity and presence or absence of aggregation of the oil-in-water emulsion compositions before and after heating to 121°C and cooling to 25°C were visually confirmed, and the compositions were evaluated according to the following criteria. The results are shown in Table 9. ◎: The emulsion composition had no aggregation and had good fluidity. ○: The emulsion composition had slight aggregation, but had good fluidity. △: The emulsion composition had aggregation, but had good fluidity. ×: The emulsion composition had aggregation, and had poor fluidity.

[0157] As is clear from the results shown in Table 9, the emulsion composition according to one embodiment of the present invention was flowable without aggregation even after the temperature was lowered, and was able to maintain a stable emulsion state even in a temperature range where the oil or fat, which is the discontinuous phase of the emulsion, changes from a liquid state to a solid state.

[0158] (Evaluation 3) Measurement of particle size distribution of oil droplet diameter of emulsion before and after heating. The pH and particle size distribution were measured for the samples before and after heating at 121°C for 30 minutes in (Evaluation 1) above. These results are shown in Table 10. The rate of change in oil droplet diameter before and after heating at 121°C was calculated and is shown in Table 10. Graphs analyzing the particle size distribution measurement results before and after heating on a volume basis are shown in Figures 11 to 13. Graphs plotting the median diameter of oil droplets, which are the internal phase of the emulsion, and the amount of polysaccharide added before and after heating are shown in Figures 14 and 15. After heating at 121°C, the samples were allowed to cool to below room temperature and then used for measurements at room temperature.

[0159]

[0160] Here, attention is focused on the rate of change in median diameter before and after heating. The rate of change in median diameter of the oil-in-water emulsion compositions B1-1 to B1-3, B1-5, and B1-6 according to Examples 1-2 to 3-2, 5-2, and 6-2 is suppressed to be lower than that of the oil-in-water emulsion compositions B1-7, B2-1, B1-8, and B1-9 according to Comparative Examples 1-2 to 4-2. From these results, it can be seen that the emulsion composition of the present invention is a highly heat-resistant emulsion composition that has high stability against high-temperature heating and cooling after high-temperature heating (crystallization of the internal phase oil due to cooling).

[0161] The emulsion compositions according to the first and second aspects of the present invention will be described below.

[0162] [Evaluation of Raw Material Protein] (Evaluation of Protein Amount in Raw Material Protein (P70)) P70 was subjected to quantitative amino acid analysis (quantitation of hydrolyzed amino acid amount, quantitation of free amino acid amount), and the protein content in terms of BSA was calculated from the results as follows: Protein content in terms of BSA: 76% by weight

[0163] (Analysis of surfactant components contained in raw material protein (P70)) Table 11 shows the results of quantitative analysis of phospholipids contained in P70 (rice protein) used in the examples.

[0164]

[0165] Based on the evaluation of the protein content in the raw protein (P70) and the analysis of the surface-active components contained in the raw protein, the mass ratio of phospholipids (amphiphiles) to the total solids content of the raw protein (P70) and the mass ratio of phospholipids (amphiphiles) to the total protein (protein contained in P70) were found to be the following: (Phospholipid content) / (Total amount of P70): 0.0162 (Phospholipid content) / (Protein content): 0.021 When the entire amount of raw protein (P70) is subjected to emulsification, the respective mass ratios in the total amount of emulsified composition will also be the above values, unless phospholipids or proteins from other blended ingredients are added. The above values ​​can be expected to change if a portion of the prepared protein aqueous dispersion is extracted and used. For example, if the settled coarse particles from the raw protein aqueous dispersion are separated and subjected to micronization, the phospholipids will not settle alone in water due to their molecular weight, and therefore the protein content can be expected to be overwhelmingly higher. Furthermore, when the supernatant of a raw material protein aqueous dispersion that has not been subjected to micronization is separated while avoiding the sedimentary components, the protein ratio among the constituent components decreases, and it is therefore easy to predict that the "phospholipid content / protein" ratio will increase beyond the above-mentioned value. If this value is too high, it is undesirable from the viewpoint of inhibiting the adsorption of solid particles to the water-oil interface.

[0166] According to the present invention, it is possible to provide an oil-in-water emulsion composition that does not undergo separation of the oil phase or the formation of aggregates of oil droplets and solid particles, even when subjected to high-temperature treatment such as retort treatment (121°C for 30 minutes). According to the present invention, it is possible to provide an oil-in-water emulsion composition that has both high heat resistance and temperature-drop resistance. According to the present invention, it is possible to provide an oil-in-water emulsion composition that can serve as a substitute for edible materials containing specific allergens, depending on the allergenicity of the consumer, because it uses a protein derived from a grass family plant that is unlikely to be an allergen. Furthermore, it is possible to provide an animal-derived food substitute that does not contain animal-derived ingredients, which contributes to reducing the environmental burden, a social issue.

Claims

1. An oil-in-water emulsion composition comprising solid particles, water, an oil, and at least one component selected from the group consisting of alkali metal salts and polysaccharides, wherein the solid particles are present at the interface between the water and the oil, the solid particles contain a grass family plant-derived protein, and the content of the grass family plant-derived protein relative to the total mass of the solid particles is 50 to 100 mass%.

2. The oil-in-water emulsion composition according to claim 1, wherein the solid particles have a volume-based average particle size of 0.01 μm or more and 50 μm or less.

3. The oil-in-water emulsion composition according to claim 1, wherein the mass ratio of the content of said polysaccharide to the content of said solid particles is 0.5 or less.

4. The oil-in-water emulsion composition according to claim 1, wherein the mass ratio of the content of said polysaccharide to the content of said oil or fat is 10 or less.

5. The oil-in-water emulsion composition according to claim 1, which contains said alkali metal salt and has a pH of greater than 7.

6. The oil-in-water emulsion composition according to claim 5, wherein the pH is greater than 7 and not greater than 8.

8.

7. The oil-in-water emulsion composition according to claim 1 or 5, wherein the alkali metal salt is an alkali metal salt of an inorganic acid.

8. The oil-in-water emulsion composition according to claim 1 or 5, wherein the alkali metal salt is a sodium or potassium salt of carbonate or bicarbonate.

9. The oil-in-water emulsion composition according to claim 1 or 5, wherein the protein derived from a grass family plant is a protein derived from rice.

10. The oil-in-water emulsion composition according to claim 1 or 5, wherein the content of the alkali metal salt is less than 100 mM relative to the total volume of the oil-in-water emulsion composition.

11. The oil-in-water emulsion composition of claim 1, comprising said polysaccharide, said polysaccharide being an ionic polysaccharide.

12. The oil-in-water emulsion composition according to claim 11, wherein the polysaccharide is at least one acidic polysaccharide selected from the group consisting of carrageenan, pectin, gum arabic, xanthan gum, gellan gum, agar, and gum tragacanth.

13. An oil-in-water emulsion composition comprising solid particles, water, and an oil and fat, and having a thermal history of being heated at a temperature exceeding 95°C, wherein the solid particles comprise a protein derived from a grass family plant, and the oil and fat form oil droplets with a diameter of 0.2 μm or more and 1 mm or less.

14. A method for producing an oil-in-water emulsion composition comprising solid particles, water, oil and an alkali metal salt, the method comprising the steps of: mixing an aqueous phase component containing an alkali metal salt with solid particles to form a first mixture, and stirring the first mixture; and mixing the mixture obtained in the first step with an oil phase component to form a second mixture, and stirring the second mixture, wherein the solid particles comprise a protein derived from a grass family plant.

15. The method of claim 14, wherein the aqueous phase component containing the alkali metal salt has a pH greater than 7.

16. The method of claim 14 or 15, further comprising a step of refining the solid particles.

17. The method of claim 14 or 15, further comprising the step of heating at a temperature above 95°C.

18. A method for producing an oil-in-water emulsion composition comprising solid particles, water, oils and polysaccharides, comprising: a step of mixing an aqueous phase component with solid particles to form a first mixture, and stirring the first mixture; a step of mixing the mixture obtained in the previous step with an oil phase component to form a second mixture, and stirring the second mixture; and a step of adding a polysaccharide to an emulsion obtained by stirring the second mixture, wherein the solid particles comprise a protein derived from a grass family plant.

19. The method of claim 18, further comprising the step of micronizing the solid particles.

20. The method of claim 18 or 19, further comprising the step of heating at a temperature above 95°C.

21. A food product comprising the oil-in-water emulsion composition according to claim 1, 5, 11 or 13.

22. A milk replacer comprising the oil-in-water emulsion composition of claim 1, 5, 11 or 13.

23. A pharmaceutical comprising the oil-in-water emulsion composition of claim 1, 5, 11 or 13.

24. A cosmetic comprising the oil-in-water emulsion composition according to claim 1, 5, 11 or 13.

25. A personal care product comprising the oil-in-water emulsion composition of claim 1, 5, 11 or 13.

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