Oil-in-water emulsion composition, method for producing oil-in-water emulsion composition, fine particle emulsifier, food, milk substitute, pharmaceutical, cosmetic, and personal care product

Abstract

Provided is an emulsion composition exhibiting excellent emulsion stability. An oil-in-water emulsion composition according to one example of the present invention comprises water, oil, and solid particles, wherein the solid particles are present at the interface between the water and the oil, at least a part of the solid particles are plant proteins, and the content ratio of the amphipathic substance to the plant proteins is less than 0.021.

Description

Oil-in-water emulsion composition, method for producing oil-in-water emulsion composition, microparticulate emulsifier, food, milk substitute, pharmaceutical, cosmetic and personal care product

[0001] The present invention relates to an oil-in-water emulsion composition and a method for producing the same, a microparticulate emulsifier, and foods, milk substitutes, pharmaceuticals, cosmetics, and personal care products containing the emulsion composition. This application claims priority based on Japanese Patent Application No. 2024-121067, 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, in the food industry, there has been an increasing need for an appearance that stimulates the appetite, flavor (stimulating the senses of taste and smell), texture, and attention to ingredients for health-conscious consumers. Therefore, there is a demand for the development of oil-in-water emulsions that have emulsion sizes and structures different from those of conventional emulsion compositions using surfactants.

[0004] On the other hand, with the increase in food allergy patients who develop allergies to food, the use of allergenic substances is sometimes restricted, and attention is being paid to the food ingredients used. Food allergies are highly dangerous, as they can cause serious symptoms such as itching and inflammation of the skin, and anaphylactic shock, which can lead to death. Therefore, for food applications, there is a demand for the provision of oil-in-water emulsions in which the allergenic substance in the food ingredients used is replaced with a different food ingredient, depending on the allergenic substance of the eater.

[0005] For example, when dealing with milk allergies, it is necessary to avoid milk-derived proteins as food ingredients, especially casein, which is highly allergenic, and the whey protein β-lactoglobulin. Soybean-derived proteins are also known to be allergenic substances. Other known allergens include proteins derived from peanuts and nuts such as walnuts and almonds.

[0006] In providing an emulsion composition, 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 Documents 1 and 2).

[0007] International Publication No. WO 2019 / 087666 International Publication No. WO 2019 / 240239

[0008] However, conventional Pickering emulsions have room for improvement in emulsion stability (e.g., heat resistance to withstand high-temperature treatments such as heat sterilization, temperature-lowering stability to withstand changes in the state of constituent components, emulsion stability to withstand the transport environment such as temperature changes and vibrations during transport, and emulsion stability during long-term storage). Among these, there is room for improvement in emulsion stability when the state of the oil phase component changes (heat resistance and temperature-lowering stability), particularly temperature-lowering stability when cooled (e.g., maintaining a good emulsion state when the oil phase component solidifies or crystallizes due to temperature lowering).

[0009] A first object of the present invention is to provide an emulsion composition with excellent emulsion stability. A second object of the present invention is to provide an animal-derived food substitute that does not contain animal-derived ingredients, which contributes to reducing the environmental impact, a social issue.

[0010] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that amphiphilic substances contained as impurities in commercially available vegetable protein raw materials may impair the emulsion stability of Pickering emulsions. Therefore, in the present invention, vegetable proteins obtained after reducing the content of amphiphilic substances in commercially available vegetable protein raw materials are used as solid particles in Pickering emulsions, thereby improving the emulsion stability of Pickering emulsions.

[0011] The present invention has the following aspects. [1] An oil-in-water emulsion composition comprising water, oil, and solid particles, wherein the solid particles are present at the interface between the water and the oil, at least a portion of the solid particles are vegetable proteins, and the content ratio of the amphiphilic substance to the vegetable protein is less than 0.021. [2] The oil-in-water emulsion composition of [1], wherein the vegetable protein is a protein derived from a grass family plant. [3] The oil-in-water emulsion composition of [1] or [2], wherein the amphiphilic substance is a plant-derived amphiphilic substance. [4] The oil-in-water emulsion composition of any of [1] to [3], wherein the amphiphilic substance is an ionic amphiphilic substance. [5] The oil-in-water emulsion composition of [4], wherein the ionic amphiphilic substance is a phospholipid. [6] The oil-in-water emulsion composition of [4], wherein the ionic amphiphilic substance is lysolecithin. [7] The oil-in-water emulsion composition of any of [1] to [6], wherein the pH of the aqueous phase is 3.0 to 7.5. [8] A method for producing an oil-in-water emulsion composition comprising water, oil, and solid particles, the solid particles being present at the interface between the water and the oil, wherein the solid particles are vegetable proteins obtained by removing at least a portion of an amphiphilic substance from a vegetable protein raw material. [9] A method for producing the oil-in-water emulsion composition of [8], wherein the vegetable protein is a protein derived from a grass family plant.

[10] A method for producing the oil-in-water emulsion composition of [8] or [9], wherein the amphiphilic substance is an ionic amphiphilic substance.

[11] A method for producing the oil-in-water emulsion composition of

[10] , wherein the ionic amphiphilic substance is a phospholipid.

[12] A method for producing the oil-in-water emulsion composition of

[10] , wherein the ionic amphiphilic substance is lysolecithin.

[13] A method for producing an oil-in-water emulsion composition according to any one of [8] to

[12] , further comprising adjusting the pH of the protein aqueous dispersion obtained by stirring the vegetable protein and the water to within the range of 3.0 to 7.5, and then stirring the protein aqueous dispersion with the oil.

[14] A method for producing an oil-in-water emulsion composition comprising water, oil, and solid particles, wherein the solid particles are present at the interface between the water and the oil, and the vegetable protein has a plant-derived amphiphilic substance content of less than 1.62% by mass.

[15] A method for producing an oil-in-water emulsion composition according to

[14] , wherein the vegetable protein is a protein derived from a grass family plant.

[16] A method for producing an oil-in-water emulsion composition according to

[14] or

[15] , wherein the amphiphilic substance is an ionic amphiphilic substance.

[17] A method for producing an oil-in-water emulsion composition according to

[16] , wherein the ionic amphiphilic substance is a phospholipid.

[18] A method for producing an oil-in-water emulsion composition according to

[16] , wherein the ionic amphiphilic substance is lysolecithin.

[19] A method for producing an oil-in-water emulsion composition according to any one of

[14] to

[18] , further comprising adjusting the pH of the aqueous protein dispersion obtained by stirring the vegetable protein and the water to a range of 3.0 to 7.5, and then stirring the aqueous protein dispersion with the oil.

[20] A fine particle emulsifier, wherein the content ratio of the plant-derived amphiphilic substance to the vegetable protein is less than 0.021.

[21] The microparticle emulsifier of

[20] , wherein the amphiphilic substance is an ionic amphiphilic substance.

[22] The microparticle emulsifier of

[21] , wherein the ionic amphiphilic substance is a phospholipid.

[23] The microparticle emulsifier of

[21] , wherein the ionic amphiphilic substance is lysolecithin.

[24] A food product comprising the oil-in-water emulsion composition of any of [1] to [7].

[25] A milk replacer comprising the oil-in-water emulsion composition of any of [1] to [7].

[26] A pharmaceutical product comprising the oil-in-water emulsion composition of any of [1] to [7].

[27] A cosmetic product comprising the oil-in-water emulsion composition of any of [1] to [7].

[28] A personal care product comprising the oil-in-water emulsion composition of any of [1] to [7].

[0012] According to the present invention, an emulsion composition having excellent emulsion stability can be provided.

[0013]

[0033] Figure 1 shows the zeta potential measurement results and hydrodynamic diameter of hardened palm oil aqueous dispersions at each pH.

[0034] Figure 1 shows an SEM image of P70 (rice protein) used in the examples (photograph substitute for drawing).

[0035] Figure 1 shows an SEM image of protein aqueous dispersion A2 (photograph substitute for drawing).

[0036] Figure 1 shows an SEM image of protein aqueous dispersion E (photograph substitute for drawing).

[0037] Figure 1 shows an optical microscope photograph of protein aqueous dispersion K (photograph substitute for drawing).

[0038] Figure 1 shows the particle size distribution measurement results of P70 aqueous dispersion.

[0039] Figure 2 shows the particle size distribution measurement results of protein aqueous dispersion M.

[0040] Figure 2 shows the particle size distribution measurement results of protein aqueous dispersion M-3.

[0041] Figure 2 shows an optical microscope photograph of emulsified composition L (photograph substitute for drawing).

[0042] Figure 2 shows an optical microscope photograph of emulsified composition A (photograph substitute for drawing).

[0043] Figure 2 shows an optical microscope photograph of emulsified composition B (photograph substitute for drawing).

[0044] Figure 2 shows an optical microscope photograph of emulsified composition C (photograph substitute for drawing).

[0045] Figure 2 shows an optical microscope photograph of emulsified composition D (photograph substitute for drawing).

[0046] Figure 2 shows an optical microscope photograph of emulsified composition E (photograph substitute for drawing). 1 is an optical microscope photograph (a drawing substitute photograph) of emulsion composition F. FIG. 2 is an optical microscope photograph (a drawing substitute photograph) of emulsion composition G. FIG. 3 is an optical microscope photograph (a drawing substitute photograph) of emulsion composition H. FIG. 4 is an optical microscope photograph (a drawing substitute photograph) of emulsion composition N.

[0014] Hereinafter, embodiments of the present invention will be described in detail. The following description of the components relates to one example, a representative example, or a preferred example of the embodiment of the present invention, and the present invention is not limited to these examples.

[0015] [Oil-in-water emulsion composition] One embodiment of the present invention relates to an oil-in-water emulsion composition. The oil-in-water emulsion composition contains water, oil, and solid particles. In the oil-in-water emulsion composition, the solid particles are present at the interface between the water and the oil. In the oil-in-water emulsion composition, at least a portion of the solid particles is vegetable protein. The content ratio of the amphiphilic substance to the vegetable protein is less than 0.021.

[0016] In this specification, the oil-in-water emulsion composition may include not only so-called O / W type oil-in-water emulsion compositions in which the continuous phase is water, but also multiphase emulsions such as W / O / W type oil-in-water emulsion compositions.

[0017] As used herein, "solid particles" refers to particles that are insoluble or poorly soluble in a medium that can be used in an oil-in-water emulsion composition, such as water and oils and fats. "Insoluble" or "poorly soluble" as used herein means that the particles are dispersible in a solvent (medium) without dissolving. In other words, the particle size (major axis size, etc.) in the solvent (medium) can be specified.

[0018] 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 with a melting point within this range, an oil-in-water emulsion composition having high heat resistance can be obtained.

[0019] The emulsion composition according to the present embodiment is emulsified by solid particles. In this case, "emulsified" can be rephrased as a state in which solid particles are present at the interface between water and oil constituting the oil-in-water emulsion composition. In addition, in the emulsion composition, the solid particles are usually present at the interface between water and oil, but are not limited thereto, and may include solid particles dispersed in water or oil.

[0020] (Solid Particles) In one embodiment, the solid particles are particles that are insoluble or poorly soluble in a medium that can be used in 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, and 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 two or more types of solid particles selected arbitrarily may be used in combination. Furthermore, the form of the solid particles before dispersion in a medium may be powder, paste, or pellet.

[0021] In one embodiment, at least a portion of the solid particles are vegetable protein. The vegetable protein is prepared from a vegetable protein material. For example, commercially available vegetable protein materials contain impurities, at least a portion of which are amphiphilic substances. In the present invention, emulsion stability is improved by washing the vegetable protein material (by removing at least a portion of the amphiphilic substance from the vegetable protein material) until the weight ratio of the amphiphilic substance content to the total amount of vegetable protein is less than 0.021. The amphiphilic substance content ratio to the vegetable protein is preferably 0.018 or less, more preferably 0.015 or less, even more preferably 0.012 or less, particularly preferably 0.010 or less, and most preferably 0.005 or less. Here, the "ratio of amphiphilic substance content to vegetable protein" refers to the "weight ratio of the amphiphilic substance content to the total solid content of the vegetable protein" or the "weight ratio of the amphiphilic substance content to the protein content contained in the vegetable protein." Among these, the "ratio of amphiphilic substance content to vegetable protein" is more preferably the "weight ratio of amphiphilic substance content to the protein amount contained in vegetable protein." The protein amount can be measured by known methods. For example, protein quantification using amino acid analysis, Kjeldahl method, combustion method, absorptiometry (ultraviolet absorptiometry, Lowry method, BCA method, Bradford method), fluorometry, and polyacrylamide electrophoresis can be selected depending on the properties of the sample. Among these, the method of calculating the protein amount converted to BSA (Bovine Serum Albumin) by amino acid analysis is more preferred.

[0022] One embodiment relates to a microparticulate emulsifier having a content ratio of amphiphilic substance to vegetable protein of less than 0.021. The microparticulate emulsifier is composed of solid particles, at least a portion of which is vegetable protein. Details and preferred aspects of the content ratio of amphiphilic substance to vegetable protein are as described above.

[0023] An amphiphilic substance refers to a substance that possesses a hydrophilic group and a hydrophobic group in its molecular structure and has surface activity. The amphiphilic substance is preferably a naturally occurring amphiphilic substance, more preferably a plant-derived amphiphilic substance, even more preferably a spermatophyte-derived amphiphilic substance, particularly preferably a monocotyledonous plant-derived amphiphilic substance, even more preferably a grass or legume-derived amphiphilic substance, and most preferably a grass (e.g., rice or rice)-derived amphiphilic substance. The term "naturally occurring or plant-derived amphiphilic substance" also includes amphiphilic substances derived from animals and plants (including spermatophytes, ferns, mosses, and algae) that have been decomposed or processed by enzymatic treatment or the like. An example of an amphiphilic substance decomposed or processed by enzymatic treatment or the like is lysolecithin, which will be described later. The amphiphilic substance is not particularly limited, but examples thereof include glycolipids, fatty acids, phospholipids, and water-soluble proteins. Examples of amphipathic substances include water-soluble / water-dispersible surfactants. Examples of water-soluble / water-dispersible surfactants include nonionic surfactants and ionic surfactants (anionic surfactants, cationic surfactants, and amphoteric surfactants), with ionic surfactants being preferred as water-soluble / water-dispersible surfactants. Examples of nonionic surfactants include monoglycerides, diglycerides, and neutral glycolipids. Examples of ionic surfactants include phospholipids, ionic glycolipids (acidic glycolipids), fatty acids, and water-soluble proteins. Among these, phospholipids are preferred. Furthermore, among water-soluble / water-dispersible surfactants, water-soluble surfactants are more preferred. In particular, the water-soluble surfactant molecules constituting water-soluble surfactants tend to significantly reduce the surface tension of water and the interfacial tension at the oil-water interface. Therefore, when such substances coexist with solid particles, they reversibly adsorb to the oil-water interface before the solid particles do, inhibiting the adsorption of the solid particles to the oil-water interface, and as a result inhibiting a higher degree of emulsion stabilization, making them even more preferable as amphiphilic substances to be removed.

[0024] Examples of phospholipids include lecithin, lysolecithin, phosphatidylcholine, phosphatidylinositol, phosphatidylserine, lysophosphatidylcholine, phosphatidylethanolamine, N-acylphosphatidylethanolamine, lysophosphatidylethanolamine, phosphatidylglycerol, and phosphatidic acid. Among these, lysolecithin is preferred, and lysophosphatidylcholine is more preferred.

[0025] The amphiphilic substance in this embodiment is preferably a low-molecular-weight amphiphilic substance, 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. By removing a portion of the amphiphilic substance contained as an impurity from the vegetable protein raw material so that the ratio falls within the above range, the amphiphilic substance can be first adsorbed to the oil-water interface, and a state can be created in which it does not physically inhibit interfacial adsorption of solid particles. In other words, it is possible to impart a high degree of emulsion stability to the emulsion composition.

[0026] When the amphiphilic substance contained in the vegetable protein is, in particular, an ionic amphiphilic substance (an ionic surfactant such as a phospholipid) or a low molecular weight amphiphilic substance, the ionic amphiphilic substance or the low molecular weight amphiphilic substance will be present before the solid particles adsorb to the oil-water interface to be stabilized, and for example, the oil droplet surface will temporarily become highly negatively charged in absolute value, which may inhibit the adsorption of the negatively charged solid particles due to electrostatic repulsion or physical obstruction may inhibit the adsorption of the solid particles to the interface, which is undesirable. By subjecting the vegetable protein from which a portion of the ionic amphiphilic substance has been removed to emulsification, an emulsion composition with excellent emulsion stability can be obtained.

[0027] Examples of plant proteins include proteins derived from legumes, grasses, Chenopodiaceae, and Brassicaceae plants. Examples of legumes include Phaseolus vulgaris, Chickpea, Pisum sativus, Lentil, and Lupinus. Examples of grasses include wheat, oats (avian oats), rye, barley, corn, sorghum, and rice. Examples of Chenopodiaceae include beets, sugar beets, and spinach. Examples of Brassicaceae include cabbage and rapeseed.

[0028] The vegetable protein is not particularly limited, but is preferably a protein derived from a legume or a grass, and more preferably a protein derived from a grass. The vegetable protein may be a protein obtained from the plant itself, a protein obtained by precision fermentation (a protein produced by the action of microorganisms such as fungi or yeast), or a protein artificially produced based on genetic information. From the perspective of providing foods that are suitable for religious restrictions and vegetarians, vegetable protein obtained from plants is preferred.

[0029] Here, the advantages of selecting proteins derived from legumes are described. Among these plant proteins, proteins derived from legumes are preferred because legumes have a higher protein content than other plants. Furthermore, proteins derived from legumes are preferred from the perspective of reducing the global environmental impact during production. Legumes can utilize atmospheric nitrogen by living in symbiosis with rhizobia, allowing them to grow even in poor soil with low nitrogen nutrition. Therefore, it is expected that cultivation will become possible without relying on nitrogen fertilizer. Among legumes, plants from the genus Pisum are preferred because they are less allergenic and more digestible than soybeans. Examples of plants from the genus Pisum include yellow peas (Pisum sativum), green peas, purple peas, blue peas, red peas, and white peas.

[0030] The term "grass family" refers to plants belonging to the Poaceae family, but is not particularly limited thereto. The solid particles may be composed of proteins derived from any plant classified as a grass family. Examples of grass family plants include rice (including rice seeds, brown rice, polished rice, and rice), wild rice, corn (maize), 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 corn (corn) are preferred, and rice (rice seeds, brown rice, polished rice, and rice) are more preferred. In particular, in the case of rice, examples of rice include rice seeds, rice, unhulled rice, brown rice, polished rice (white rice, etc.), rice bran, and the like. Rice seeds, rice, brown rice, and polished rice are preferred, rice, brown rice, and polished rice are more preferred, and polished rice is even more preferred.

[0031] 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, Barnyard Millet, Setaria, Maize, Saccharum, and Miscanthus are preferred, with Oryza and Maize being more preferred, and Oryza being even more preferred.

[0032] Since the above-mentioned grass family plant-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 family plant-derived proteins, it becomes possible to provide foods that comply with food restrictions due to food allergies (e.g., milk allergies, soy allergies), i.e., restrictions on food ingredients. Furthermore, the use of the above-mentioned specific grass family plant-derived proteins makes it possible to provide emulsified compositions and foods with better flavor.

[0033] It is also possible to appropriately select and use proteins derived from the above-mentioned preferred grass plants. For example, by selecting and using proteins derived from plants other than wheat (rice, rice, etc.), it is possible to provide wheat- and gluten-free foods that are a countermeasure against celiac disease and wheat allergies caused by the intake of wheat flour.

[0034] A portion of the solid particles may be one type of vegetable protein, or two or more types of vegetable proteins may be used in combination. Furthermore, a portion of the solid particles may be other components besides vegetable proteins. Examples of other components besides vegetable proteins include polysaccharides and inorganic substances such as minerals. These other components may be complexed with the vegetable proteins through interactions such as electrostatic interactions, hydrophobic interactions, and intermolecular interactions including hydrogen bonds, or each may function independently as a solid particle. The vegetable protein constituting the solid particles is typically more than 0% by mass, preferably 1% by mass or more, more preferably 10% by mass or more, even more preferably 30% by mass or more, particularly preferably 50% by mass or more, especially preferably 70% by mass or more, most preferably 80% by mass or more, especially preferably 90% by mass or more, and most preferably 93% by mass or more, based on the total amount of the solid particles. The upper limit of the weight ratio of vegetable protein to the total amount of solid particles is usually 100% by mass or less, preferably 99% by mass or less, more preferably 98% by mass or less, even more preferably 97% by mass or less, particularly preferably 96% by mass or less, and especially preferably 95% by mass or less. The upper and lower limits of the weight ratio of vegetable protein to the total amount of solid particles can be arbitrarily combined, and in one embodiment, it can be 1% by mass or more and 100% by mass or less, 10% by mass or more and 100% by mass or less, 50% by mass or more and 100% by mass or less, 70% by mass or more and 100% by mass or less, 80% by mass or more and 100% by mass or less, 80% by mass or more and 95% by mass or less, or 90% by mass or more and 95% by mass or less. When the vegetable protein content ratio (weight ratio) is within the above range, the contact probability of solid particles with the interface during stirring for emulsification is favorable, and the solid particles can be efficiently adsorbed to the interface, resulting in the formation of a stable emulsion composition.

[0035] The vegetable protein is preferably a protein with moderate hydrophobicity. A protein with moderate hydrophobicity means a protein with a high content of hydrophobic amino acids among its constituent amino acids. That is, when a large amount of hydrophobic amino acids is contained, the water solubility of the protein decreases, forming a hydrophobic protein. Examples of hydrophobic amino acids include leucine, isoleucine, valine, phenylalanine, proline, glutamine, and asparagine.

[0036] The contact angle of a vegetable protein 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.

[0037] The contact angle can be measured by forming solid particles into tablets and measuring the contact angle on the tablets at room temperature using a contact angle measuring device. Alternatively, the contact angle can be measured over time after water is dropped by contact or by its own weight, and in order to minimize the influence of surface irregularities and liquid absorption into the porous parts of the tablet, the contact angle at the time of droplet landing (t=0) can be calculated by linear approximation using measured values ​​where the change in contact angle with time (t) after droplet landing is approximately linear, and this can be used as the contact angle of water on the solid particles.

[0038] When the contact angle of water with solid particles containing vegetable protein is within the above range, the wettability of the solid particles becomes moderately hydrophobic. When such a substance having moderate hydrophobicity is used for the solid particles, it is possible to efficiently emulsify water with oils and fats (animal fats and oils, vegetable fats and oils, edible oils, etc.) that are less polar than hydrocarbons such as n-dodecane, 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.

[0039] By setting the contact angle of water to the vegetable protein within the above range, the vegetable protein has appropriate hydrophobicity, and therefore, when used for solid particles, it can efficiently emulsify water with fats and oils (animal fats and oils, vegetable fats and oils, edible oils, etc.) that have lower polarity than hydrocarbons such as n-dodecane, and form an emulsion structure in which the solid particles are adsorbed to the oil-water interface, thereby making it possible to obtain an emulsion composition with good emulsion stability.

[0040] 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.

[0041] The taste, color, and odor of the solid particles themselves may affect oral intake of foods, etc. Therefore, from the viewpoint of flavor, it is preferable to use proteins derived from grass plants (rice-derived proteins, rice-derived proteins, polished rice-derived proteins, etc.) rather than maize-derived proteins or wheat-derived proteins, which have unique odors.

[0042] Furthermore, if the solid particles have a dark, deep 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, coloring agents, 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] In one embodiment, the solid particles are composed of rice-derived protein. In another embodiment, the content of the rice-derived protein relative to the total mass of the solid particles is typically 1 to 100% by mass, preferably 3 to 100% by mass, more preferably 5 to 100% by mass, even more preferably 10 to 100% by mass, particularly preferably 50 to 100% by mass, especially preferably 60 to 100% by mass, most preferably 70 to 100% by mass, and even 100% by mass. In yet another embodiment, the content of 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 3 to 100% by mass, even more preferably 5 to 100% by mass, especially preferably 10 to 100% by mass, especially preferably 20 to 100% by mass, and most preferably 50 to 100% by mass.

[0048] In one embodiment, the vegetable 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. Such treatment can physically and / or chemically modify (denaturate, etc.) the protein, thereby controlling the wettability of the protein or particles formed from the protein (protein aggregates, protein-containing complexes). 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), allowing the formation of 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.

[0049] 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 with a denaturant and denaturation treatment with 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, even more preferably 80°C or higher, particularly preferably 90°C or higher, particularly preferably 95°C or higher, particularly preferably 100°C or higher, most preferably 105°C or higher, particularly most preferably 110°C or higher, and especially preferably 120°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., it is sufficient if it is less than 200°C, and is preferably 190°C or less, more preferably 180°C or less, even more preferably 170°C or less, especially preferably 160°C or less, particularly preferably 155°C or less, especially preferably 150°C or less, most preferably 145°C or less, particularly most preferably 140°C or less, and especially preferably 130°C or less.

[0050] If the temperature during the heat treatment of the vegetable protein is within the above range, the desired physical properties of the vegetable protein (i.e., the desired physical properties of the solid particles) can be efficiently obtained, and therefore, the emulsion stabilizing effect of the vegetable protein (solid particles) can be obtained. If the heating temperature is not too low, conformational changes in the vegetable protein are not difficult to induce, and as a result, the desired physical properties of the solid particles are achieved, and the emulsion stabilizing effect of the solid particles tends to be efficiently obtained. If the heating temperature is not too high, the desired physical properties of the solid particles tend to be efficiently obtained due to excessive denaturation or decomposition of the protein, and the emulsion stabilizing effect of the solid particles tends to be easily obtained.

[0051] The heat treatment time may be any time, 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, particularly preferably 30 minutes or more. The upper limit of the heat treatment time is usually 120 minutes or less, preferably 115 minutes or less, more preferably 110 minutes or less, even more preferably 105 minutes or less, particularly preferably 100 minutes or less, particularly preferably 95 minutes or less, particularly preferably 90 minutes or less, most preferably 85 minutes or less, particularly most preferably 80 minutes or less, and particularly preferably 70 minutes or less. If the treatment time is within the above range, the desired physical properties tend to be easily obtained efficiently.

[0052] The vegetable protein treatment may include a step of treating at a pressure other than atmospheric pressure in addition to the heat treatment step. The heat treatment may be followed by a step of treating at a pressure other than atmospheric pressure, or the step of treating at a pressure other than atmospheric pressure and the heat treatment may be performed simultaneously. Performing the heat treatment under a pressure other than atmospheric pressure is preferred because it shortens the process and allows for more efficient treatment.

[0053] By performing heat treatment under pressure other than atmospheric pressure, the desired physical properties of solid particles can be efficiently obtained, and therefore, it is possible to obtain the emulsion stabilizing effect of solid particles composed of vegetable protein.By combining heating and pressurization, it is possible to keep the heating temperature low and shorten the process time, and efficiently produce vegetable protein (i.e., solid particles) with the desired physical properties.When treating under pressure other than atmospheric pressure, the gauge pressure is usually greater than or less than 0 MPa.The lower limit of the gauge pressure is preferably greater than 0 MPa, more preferably 0.02 MPa or more, even more preferably 0.05 MPa or more, particularly preferably 0.06 MPa or more, particularly preferably 0.07 MPa or more, especially preferably 0.08 MPa or more, most preferably 0.09 MPa or more, particularly most preferably 0.10 MPa or more, and especially preferably 0.11 MPa or more. The upper limit of the gauge pressure is preferably 800 MPa or less, more preferably 500 MPa or less, even more preferably 300 MPa or less, particularly preferably 250 MPa or less, particularly preferably 150 MPa or less, especially preferably 50 MPa or less, most preferably 10 MPa or less, particularly most preferably 1 MPa or less, and especially preferably 0.50 MPa or less. By treating under a pressure within the above range, the desired physical properties of the vegetable protein (solid particles) can be efficiently obtained, and therefore, the vegetable protein (solid particles) can have an emulsion stabilizing effect.

[0054] The shape of the solid particles is not limited, and examples thereof include spheres, rods, strings, gels, meshes, porous particles, needles, and flakes. The solid particles may be in the form of a gel containing a medium (water, oil, gas, etc.), and in the case of a gel, they may be shrunk or swollen. The solid particles may be formed from a single component or a mixture of multiple different components. Furthermore, 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.

[0055] 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, etc. The primary particle size is usually 0.001 μm or more, preferably 0.01 μm or more, preferably 0.05 μm or more, further preferably 0.1 μm or more, particularly preferably 0.5 μm or more, and usually 50 μm or less, preferably 5 μm or less, more preferably 1 μm or less, particularly preferably 0.9 μm or less.

[0056] The primary particle diameter of the solid particles is, for example, an average particle diameter of particles observable 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 diameter of the solid particles may be determined by referring to the catalog value.

[0057] 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 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 10 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, particularly preferably 40 μm or less, especially preferably 30 μm or less, most preferably 20 μm or less, and especially preferably 15 μm or less.

[0058] The lower limit and upper limit of the volume-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, 0.01 μm or more and 50 μm or less, 0.01 μm or more and 30 μm or less, or 0.1 μm or more and 20 μm or less, in another embodiment, it is 1 μm or more and 30 μm or less, in yet another embodiment, it is 1 μm or more and 20 μm or less, and in yet another embodiment, it is 10 μm or more and 20 μm or less.

[0059] Here, the term "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 is usually 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.

[0060] The volume-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 5 μm or more, and most preferably 10 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 40 μm or less, especially preferably 30 μm or less, and most preferably 20 μm or less.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] The lower and upper limits of the number-based median diameter can be arbitrarily combined, and in one embodiment, it is 0.01 μm to 100 μm, 0.05 μm to 80 μm, 0.1 μm to 60 μm, 1 μm to 50 μm, or 5 μm to 30 μm, in another embodiment, it is 5 μm to 10 μm, or in still another embodiment, it is 5 μm to 6 μm. By setting the size of the solid particles in the medium within the above ranges, the dispersibility of the solid particles in the medium is improved, the probability of contact with the oil-water interface is improved, the solid particles can be efficiently adsorbed to the oil-water interface, and further, the solid particles adsorbed to the oil-water interface can be prevented from detaching from the interface or settling due to the influence of gravity, thereby obtaining a stable emulsion composition.

[0066] The size of solid particles 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 may be either number-based or volume-based, but volume-based analysis is more preferable. When measurement using a laser diffraction / scattering particle size distribution analyzer is difficult, the particle size distribution, average particle size, or median size of solid particles dispersed in a liquid may 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.

[0067] In one embodiment, from the viewpoint of dispersing the solid particles constituting the oil-in-water emulsion composition, controlling the particle size, etc., it is preferable to separately subject the solid particles to a crushing treatment, a pulverizing treatment, or a dispersion treatment. There is no limitation on the method of these treatments, and the treatment may be carried out in a dry system or a wet system. The crushing and / or pulverizing, or the dispersion treatment may be carried out in a stepwise manner using a combination thereof.

[0068] Examples of wet processing 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 processing 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 and high-pressure homogenizers being more preferred. Use of a high-pressure homogenizer or ultra-high pressure homogenizer can better prevent undesirable contamination of inorganic substances derived from beads.

[0069] When beads are used in wet treatment, beads having a diameter of about 0.05 to 5 mm are preferably used. There are no limitations on the material of the beads, and for example, glass beads, special glass beads, alumina beads, zirconia-silica ceramic beads, zirconia beads, silicon nitride beads, and steel beads can be used.

[0070] 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. 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 above upper and lower limits can be combined in any manner.

[0071] The treatment time is usually 30 seconds or more, preferably 1 minute or more, more preferably 1 minute 30 seconds or more, more preferably 2 minutes or more, even more preferably 30 minutes or more, particularly preferably 1 hour or more, and most preferably 2 hours or more. The treatment time can usually be 10 hours or less, preferably 8 hours or less, more preferably 7 hours or less, and even more preferably 6 hours or less. If the treatment time is not too short, particle size control tends to be less difficult, and if the treatment time is not too long, productivity tends to be less likely to decrease. The above upper and lower limits can be combined arbitrarily.

[0072] In one embodiment, in order to produce solid particles that are components of an oil-in-water emulsion composition, the disintegrated particles obtained by the above-mentioned production method may be subjected to a particle size classification treatment. The classification conditions may be such that the mesh size is usually 150 μm or less, preferably 106 μm or less, more preferably 53 μm or less, more preferably 45 μm or less, more preferably 38 μm or less, and even more preferably 20 μm or less.

[0073] The apparatus used for the classification treatment is not particularly limited, but in the case of dry sieving, for example, a rotary sieve, a shaking sieve, a gyrating sieve, or a vibrating sieve can be used; in the case of dry airflow classification, for example, a gravity classifier, an inertia classifier, or a centrifugal classifier (classifier, cyclone, etc.) can be used; and in the case of wet sieving, for example, a mechanical wet classifier, a hydraulic classifier, a sedimentation classifier, or a centrifugal wet classifier can be used.

[0074] In one embodiment, the size of solid particles present at the interface between the aqueous phase and the oil phase in the 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 usually 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 usually 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.

[0075] The lower and upper limits of the average particle size can be arbitrarily combined. In one embodiment, it is 0.05 μm to 30 μm, and 0.1 μm to 20 μm. In another embodiment, it is 0.5 μm to 15 μm. In yet another embodiment, it is 1 μm to 10 μm. The solid particles (vegetable proteins) present at the interface between water and oil may be present in a state where they maintain their size and shape in the dispersion medium, or may be present in a layered or aggregated state at the interface. The solid particles (vegetable proteins) may be densely adsorbed at the interface between water and oil, or may be present in a layered state due to intermolecular interactions, i.e., in a film-like shape. In the case of a film state, the film pressure is the above-mentioned size. If the size of the solid particles present at the aqueous phase-oil phase interface is within the above-mentioned range, there is no strange feeling in the mouth and the texture is not impaired.

[0076] The number-based average particle size of solid particles present at the aqueous phase-oil phase interface is, for example, the average particle size of particles that can be observed on a magnified image of particles obtained by measurement with an optical microscope or a scanning electron microscope (SEM). Observation using a scanning electron microscope is preferred. The number of particles observed may be 5 or more, 40 or more, 100 or more, or 200 or more.

[0077] When it is difficult to measure using a laser diffraction / scattering particle size distribution analyzer, the particle size distribution, average particle size, or median size of solid particles dispersed in a liquid may be measured by dynamic light scattering. The measurement results by dynamic light scattering can be analyzed, for example, by the cumulant method.

[0078] 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.

[0079] The lower and upper limits of the solid particle content can be arbitrarily combined. In one embodiment, the solid particle content is 0.001% by mass to 30% by mass, 0.001% by mass to 20% by mass, or 0.001% by mass to 10% by mass, relative to the total mass of the oil-in-water emulsion composition. In another embodiment, the solid particle content can be 0.001% by mass to 5% by mass. If the solid particle content is equal to or less than the upper limit, thickening when dispersed in a medium is suppressed, and handling tends to be improved. If the solid particle content is equal to or greater than the lower limit, adsorption of the solid particles to the water-oil interface during formation of the emulsion composition, i.e., sufficient coverage of the oil droplets with the solid particles, tends to provide sufficient emulsion stabilization function (stabilization due to adsorption to the water-oil interface) in a process involving a change in the state of the continuous and / or discontinuous phase of the emulsion composition.

[0080] (Oil Phase Component) In one embodiment, the oil (e.g., fat or oil) 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 (animal oils such as beef tallow, lard, and fish oil; vegetable oils such as soybean oil, rapeseed oil, sunflower oil, cottonseed oil, coconut oil, palm oil, linseed oil, and castor oil; etc.), isoprenoids including squalene and tocopherol, higher alcohols, synthetic ester oils, glycol higher fatty acid esters, saturated fatty acids, and unsaturated fatty acids.

[0081] The oil phase component preferably contains any of those usable for food (hereinafter referred to as "edible oils and fats"), those usable for cosmetics, and those usable for pharmaceuticals, and any of these oil phase components can be used. Among these, the use of animal and vegetable oils and fats (hereinafter referred to as "oils and fats") is more preferred, and from an environmentally friendly perspective, the use of vegetable oils and fats, their hydrogenated oils, and processed oils and fats is even more preferred. The oil phase component particularly preferably contains those usable for food (hereinafter referred to as "edible oils and fats"), and any of these edible oils and fats can be used. As the edible oils and fats, physiologically functional oils and fats, fat-soluble pigments, and antioxidants can also be used.

[0082] Examples of the oils and fats or 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 and fats or animal oils such as those described above through refining, deodorizing, fractionating, hardening, or interesterification. For example, one or more of hydrogenated oils and processed oils such as hydrogenated coconut oil and hydrogenated palm kernel oil; and liquid oils or solid fats obtained by further fractionating these oils and fats can be used. In addition, physiologically functional fats and oils can also be used, and specific examples thereof include docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), arachidonic acid, α-linolenic acid, γ-linolenic acid, and medium-chain triglycerides (MCT). These fats and oils can be used alone or in combination.

[0083] Fat-soluble pigments and antioxidants can also be used. Examples of pigments 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 food tar-based pigments. Examples of 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.

[0084] As the oil phase component, from the viewpoints of taste, moisture retention, protection, spreadability, and tactile feel, room temperature solid fats are particularly preferred. Room temperature solid fats are solid fats that exist in a solid state at room temperature (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 preferable 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.

[0085] 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; hydrogenated animal fats; solid fats obtained by fractionating vegetable oils and fats or hardened or processed animal fats; and medium-chain triglycerides (MCT). More preferred oil phase components are palm kernel oil, coconut oil, milk fat, hardened coconut oil, hardened palm kernel oil, and medium-chain triglycerides (MCT), even more preferred oil phase components are palm kernel oil, coconut oil, hardened coconut oil, and hardened palm kernel oil, and especially preferred oil phase component is hardened coconut oil. These oils and fats may be used alone or as a mixture.

[0086] In particular, for the above-mentioned oils and fats or edible oils and fats, the proportion of unsaturated fatty acids other than saturated fatty acids, i.e., including trans fatty acids, in all fatty acids bonded to the triglyceride molecules that 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, in the edible oils and fats, the proportion of fatty acids having 12 or less carbon atoms in all fatty acids bonded to the 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.

[0087] The iodine value of the fats and oils and edible fats and oils is preferably 200 or less, more 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, the fats and oils and edible fats and oil ...

[0088] 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 oil or fat, or the edible oil or fat, is usually -20°C or higher, preferably -15°C or higher, more preferably -10°C or higher, even more preferably 0°C or higher, especially more preferably 5°C or higher, particularly preferably 10°C or higher, especially preferably 15°C or higher, most preferably 20°C or higher, especially most preferably 25°C or higher, and especially preferably 26°C or higher. The upper limit of this slip melting point is usually 190°C or lower, preferably 100°C or lower, more preferably 90°C or lower, even more preferably 80°C or lower, especially more preferably 70°C or lower, especially preferably 60°C or lower, especially preferably 50°C or lower, most preferably 45°C or lower, especially most preferably 40°C or lower, and especially preferably 35°C or lower, which is suitable for obtaining good emulsion stability. The slip melting point can be measured by a known method.

[0089] The melting point can also be measured by known measurement methods using DSC, a melting point measuring device, or the like. There are no limitations on the melting point of the oil or fat used, but it is usually -20°C or higher, preferably -15°C or higher, more preferably -10°C or higher, even more preferably 0°C or higher, especially more preferably 5°C or higher, particularly preferably 10°C or higher, especially preferably 15°C or higher, most preferably 20°C or higher, especially most preferably 25°C or higher, and especially preferably 26°C or higher, which is suitable for producing a composition with a good flavor. The upper limit of the melting point is usually 190°C or lower, preferably 100°C or lower, more preferably 90°C or lower, even more preferably 80°C or lower, especially more preferably 70°C or lower, especially preferably 60°C or lower, especially preferably 50°C or lower, most preferably 45°C or lower, especially most preferably 40°C or lower, and especially preferably 35°C or lower, which is suitable for obtaining good emulsion stability. If the physical properties of the edible oil or fat are within the above ranges, the texture, appearance, feel, viscosity, stability, etc. can be improved when made into an emulsion composition.

[0090] 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.

[0091] 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, it is possible to improve the texture, appearance, touch, viscosity, stability, etc. The average particle size of the oil phase is usually greater than 0.5 μm, preferably 1 μm or more, more preferably 1.2 μm or more, even more preferably 1.5 μm or more, especially preferably 2 μm or more, particularly preferably 2.2 μm or more, especially preferably 3 μm or more, most preferably 3.5 μm or more, especially most preferably 5 μm or more, and especially preferably 9 μm or more. 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.

[0092] The lower and upper limits of the average particle size can be arbitrarily combined, and in one embodiment, it is 0.5 μm to 1000 μm, 1 μm to 500 μm, 2.2 μm to 250 μm, 3 μm to 100 μm, and 5 μm to 50 μm. In another embodiment, it is 1 μm to 50 μm, and in still another embodiment, it is 2.2 μm to 50 μm. 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. By setting the average diameter or median diameter of the oil phase within the above range, appropriate texture, appearance, touch, viscosity, and stability can be obtained.

[0093] Such an emulsion structure can be confirmed by observation with a polarizing microscope. The size of the discontinuous phase, i.e., the oil phase, is the average size of the major axis of the discontinuous phase confirmed by observation with a polarizing microscope. The number of discontinuous phases confirmed may be 10 or more, 20 or more, 40 or more, 50 or more, 100 or more, or 200 or more.

[0094] 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, can be measured using a laser diffraction / scattering particle size distribution analyzer or a measuring device using a dynamic light scattering method. When measuring using a laser diffraction / scattering particle size distribution analyzer, there are no limitations on the analysis conditions, but it is preferable to analyze on a volume basis.

[0095] 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 0.01% by mass or more, preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, especially more preferably 2% by mass or more, particularly preferably 3% by mass or more, especially preferably 5% by mass or more, most preferably 10% by mass or more, and especially preferably 20% 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 65% ​​by mass or less, even more preferably 50% by mass or less, especially more preferably 45% by mass or less, particularly preferably 40% by mass or less, especially preferably 30% by mass or less, and most preferably 20% by mass or less.

[0096] The lower limit and upper limit of the content of the oil phase component, i.e., the oil or fat, in the oil-in-water emulsion composition can be combined in any desired manner. In one embodiment, the content is from 0.01% by mass to 65% by mass, both inclusive, relative to the total mass of the oil-in-water emulsion composition. In another embodiment, the content is from 0.1% by mass to 50% by mass, both inclusive, relative to the total mass of the oil-in-water emulsion composition. In yet another embodiment, the content is from 1% by mass to 40% by mass, both inclusive, relative to the total mass of the oil-in-water emulsion composition. In yet another embodiment, the content is from 1% by mass to 30% by mass, both inclusive, relative to the total mass of the oil-in-water emulsion composition.

[0097] 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 for sterilization, etc. 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.

[0098] (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 further include a lower alcohol and a polyhydric alcohol.

[0099] In one embodiment, the pH of the aqueous phase is preferably 3.0 to 7.5, more preferably 3.5 to 7.5, even more preferably 4.0 to 7.5, particularly preferably 4.0 to 7.0, and especially preferably 4.0 to 6.5. When the pH of the aqueous phase is within this range, the surface charge of the vegetable protein particles in the protein aqueous dispersion is less likely to become excessively negative. As a result, repulsion with negatively charged oil droplets is suppressed. This promotes adsorption of the solid particles to the oil-water interface, further improving emulsion stability.

[0100] 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 allows the formation of 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, relative to 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, relative to the total mass of the oil-in-water emulsion composition.

[0101] The lower limit and upper limit of the water content in the oil-in-water emulsion composition can be combined in any manner, and in one embodiment, the water content is 20% by mass or more and less than 100% by mass, relative to the total mass of the oil-in-water emulsion composition; in another embodiment, the water content is 40% by mass or more and less than 100% by mass, relative to the total mass of the oil-in-water emulsion composition; in another embodiment, the water content is 60% by mass or more and 99% by mass or less, relative to the total mass of the oil-in-water emulsion composition; and in still another embodiment, the water content is 80% by mass or more and 98% by mass or less, relative to the total mass of the oil-in-water emulsion composition.

[0102] (Other Components) In one embodiment, the oil-in-water emulsion composition may further contain, for example, an antioxidant, a sweetener, a stabilizer, a milk component, a flavoring agent, a coloring agent, a salt, or an organic acid, within a range that does not impair the effects of the present invention.

[0103] 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.

[0104] Stabilizers include, for example, galactomannan, xanthan gum, carrageenan, gum arabic, tamarind gum, gellan gum, glucomannan, and cellulose.

[0105] 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 portion is extracted as butter by churning or other methods from cream produced from milk by centrifugation or other methods. 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 by 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.

[0106] As described above, from the viewpoint of ensuring that the oil-in-water emulsion composition is free of allergens, it is preferable that the milk component does not contain highly allergenic casein or β-lactoglobulin, and even more preferably does not contain milk-derived proteins. Furthermore, it is preferable to use casein or β-lactoglobulin after depolymerizing it to a molecular weight sufficient to prevent allergenicity by hydrolysis with an enzyme or acid. The content of milk-derived components relative to the emulsion composition is typically 0.5% by mass or less, preferably 0.2% by mass or less, more preferably 0.1% by mass or less, even more preferably 0.05% by mass or less, even more preferably 0.01% by mass or less, and particularly preferably 0.005% by mass or less, and it is particularly preferable that the composition is substantially free of milk-derived components. "Substantially free of milk-derived components" means that the emulsion composition of this embodiment does not contain milk-derived components other than impurities contained in purified products prepared from animal, plant, or fungal raw materials. The above range is preferable from the viewpoint of allergies.

[0107] Any flavoring agent can be used. Examples include vanilla flavors such as vanilla essence; and milk flavors such as milk flavor or butter flavor, with milk flavors being particularly preferred. The milk flavor is not particularly limited as long as it is a flavor containing the aroma components of milk and contains aroma components characteristic of milk. It may be a chemically synthesized flavor, a flavor extracted and purified from milk, or a mixture thereof, but those made from milk are more preferred, and milk flavors 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 types.

[0108] Any coloring agent can be used, including, for example, cocoa color, β-carotene, annatto color, chili pepper color, turmeric color, oil red color, paprika color, naphthol yellow color, and riboflavin butyrate (VB2).

[0109] Examples of salts include chlorides such as table salt, potassium chloride, and magnesium chloride; carbonates such as sodium carbonate, potassium carbonate, and calcium carbonate; bicarbonates such as sodium bicarbonate and potassium bicarbonate; 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 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.

[0110] Examples of organic acids include fumaric acid, succinic acid, citric acid, tartaric acid, diacetyltartaric acid, malic acid, adipic acid, glutaric acid, and maleic acid.

[0111] (Effects) The oil-in-water emulsion composition 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. Such a structure allows the emulsion composition to have excellent emulsion stability (e.g., temperature drop resistance, etc.). 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, for example, 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.

[0112] In the oil-in-water emulsion composition described above, the amphiphilic substance content ratio to the vegetable protein is less than 0.021, so the amphiphilic substance is unlikely to impair the emulsion stability of the Pickering emulsion. In other words, the solid particles are well adsorbed to the surface of the oil phase emulsified in the aqueous phase, allowing the above-mentioned structure to be efficiently formed (the oil droplets are well coated with the solid particles). Having such a structure is expected to improve emulsion stability.

[0113] The presence of solid particles at the interface between the oil phase component and the aqueous phase component can be confirmed not only by observation with an optical microscope, but also by rapidly freezing an oil-in-water Pickering emulsion using a rapid freezing method such as the metal contact method with a cryo-scanning electron microscope (Cryo-SEM) or the like, and then cutting the frozen Pickering emulsion with a cryomicrotome using a diamond knife for an optical microscope to prepare a sample, and then observing the cross section of the sample with the Cryo-SEM.

[0114] [Method for Producing Oil-in-Water Emulsion Composition] In one embodiment, the method for producing an oil-in-water emulsion composition comprises using a vegetable protein obtained after removing at least a portion of the amphiphilic substance from a vegetable protein material to form solid particles. Commercially available vegetable protein materials contain impurities, at least a portion of which are amphiphilic substances. In one embodiment, emulsion stability is improved by washing the vegetable protein material until the amphiphilic substance content is less than 1.62% by mass. The amphiphilic substance content in the vegetable protein material is preferably less than 1.54% by mass, more preferably 1.50% by mass or less, even more preferably 1.40% by mass or less, particularly preferably 1.20% by mass or less, especially preferably 1.00% by mass or less, and most preferably 0.80% by mass or less. By achieving this specific content, emulsion stability can be improved. It is believed that using the vegetable protein obtained after washing the vegetable protein material to form solid particles in an oil-in-water emulsion composition promotes adsorption of the solid particles to the oil-water interface, thereby improving emulsion stability. The specific method for washing the vegetable protein raw material is not particularly limited. The washing method may be washing with water, or washing using a dialysis membrane, an ion exchange resin, or an ultrafiltration membrane.

[0115] In one embodiment, the method for producing an oil-in-water emulsion composition includes using a vegetable protein having an amphiphilic substance content of less than 1.62% by mass for the solid particles. The amphiphilic substance content in the vegetable protein material is preferably less than 1.54% by mass, more preferably 1.50% by mass or less, even more preferably 1.40% by mass or less, even more preferably 1.20% by mass or less, especially preferably 1.00% by mass or less, and most preferably 0.80% by mass or less. The use of vegetable protein having such a specific amphiphilic substance content for the solid particles enables improved emulsion stability. Commercially available vegetable protein materials contain impurities, at least a portion of which are amphiphilic substances. In one embodiment, the emulsion stability of the oil-in-water emulsion composition is improved by washing the vegetable protein material until the amphiphilic substance content is less than 1.62% by mass. The content of amphiphilic substances in the vegetable protein material is preferably less than 1.54% by mass, more preferably 1.50% by mass or less, even more preferably 1.40% by mass or less, especially preferably 1.20% by mass or less, especially preferably 1.00% by mass or less, and most preferably 0.80% by mass or less. Washing the vegetable protein material to a specific content like this can improve the emulsion stability of the oil-in-water emulsion composition. It is believed that using the vegetable protein obtained after washing the vegetable protein material to form solid particles in the oil-in-water emulsion composition promotes adsorption of the solid particles to the oil-water interface, thereby improving emulsion stability. The specific method for washing the vegetable protein material is not particularly limited. The washing method may be water washing, washing with an organic solvent, washing with an ion exchange resin, gel filtration chromatography, or ultrafiltration. Examples of organic solvents include, but are not limited to, hexane, chloroform, alcohols, and mixtures thereof. In addition to water, aqueous solutions such as buffer solutions containing salts, and mixtures thereof can also be used for washing. Among these, washing with water or aqueous solutions is preferred.Compared to degreasing using organic solvents such as n-hexane, cleaning without using organic solvents (such as cleaning with water, ion exchange resins, ultrafiltration membranes, or dialysis membranes) is advantageous in that the resulting composition does not contain organic solvents that may be harmful to the human body, and therefore is expected to be highly safe when used in food applications. Furthermore, cleaning without using organic solvents is also advantageous in that it does not use flammable substances in the manufacturing process.

[0116] The oil-in-water emulsion composition can be produced by a method known per se, except that the solid particles are vegetable proteins obtained after washing a vegetable protein raw material. For example, the oil-in-water emulsion composition can be produced by mixing the solid particles, an oil phase component, an aqueous phase component, and optionally other components, and stirring the resulting mixture using any stirring device.

[0117] Although not particularly limited, the present invention can be specifically prepared by the following method: A production method comprising: a step A1 of mixing an aqueous phase component with a vegetable protein to form a mixture and stirring the mixture; and a step A2 of mixing the mixture obtained in step A1 with the oil phase component to form a mixture and stirring the mixture; or a production method comprising: a step A1' of mixing the oil phase component with the vegetable protein to form a mixture and stirring the mixture; and a step A2' of mixing the mixture obtained in step A1 with an aqueous phase component to form a mixture and stirring the mixture.

[0118] Step A1 is a step of preparing an aqueous phase. Adding vegetable protein to an aqueous phase to prepare a vegetable protein dispersion in this manner facilitates the formation of an oil-in-water emulsion composition. The pH of the vegetable protein aqueous dispersion is preferably within the range of 3.0 to 7.5, more preferably within the range of 3.5 to 7.5, even more preferably within the range of 4.0 to 7.5, particularly preferably within the range of 4.0 to 7.0, and especially preferably within the range of 4.0 to 6.5. When the pH of the aqueous dispersion is within the above range, excessive repulsion with negatively charged oil droplets is suppressed. As a result, adsorption of solid particles to the oil-water interface is promoted, further improving emulsion stability.

[0119] Here, the vegetable protein can be obtained by washing the vegetable protein raw material to reduce at least a portion of its amphiphilic substance. In one embodiment, the aqueous phase may be prepared by preparing an aqueous dispersion of a commercially available vegetable protein raw material by stirring or the like, and then washing the aqueous dispersion of the vegetable protein raw material with water (including gravity settling, as well as centrifugation, filter filtration, and suction filtration) or washing with an ion exchange resin. Alternatively, the vegetable protein raw material may be micronized in advance by treatment with an agate mortar, or by grinding / disintegrating treatment such as freeze-grinding or dry grinding, or classification, before being subjected to washing, and the aqueous phase may be prepared using this micronized protein raw material. Alternatively, the prepared aqueous phase may be treated with a wet micronization device (e.g., a homogenizer, high-pressure homogenizer, ultra-high-pressure homogenizer, ultrasonic homogenizer, bead mill, ball mill, etc.) to micronize (also referred to as "fine-particle reduction") and disperse solid particles in the aqueous phase.

[0120] Step A1' is a step of preparing an oil phase. After the vegetable protein is present in the oil phase, an aqueous phase may be added.

[0121] The stirring of the mixture in steps A1 and A1' may be carried out at room temperature and normal pressure, or under heated and / or high pressure conditions. There are no limitations on the stirring speed or stirring time; however, a speed of 10 rpm to 20,000 rpm is usually sufficient, and the stirring time is usually 10 seconds to 5 hours. The stirring speed or stirring time may be changed in stages. Alternatively, a wet atomization device (e.g., Starburst Lab (manufactured by Sugino Machine Co., Ltd.)) as described in the examples is equipped with an oblique collision chamber, and the mixture of aqueous phase components in which solid particles are dispersed is subjected to oblique collision under ultra-high pressure, thereby atomizing (also referred to as micronization) the solid particles and dispersing them into the aqueous phase.

[0122] 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.

[0123] 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.

[0124] 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.

[0125] 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, more preferably 16000 rpm or less, even more preferably 14000 rpm or less, particularly 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.

[0126] 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.

[0127] 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. Sterilization treatment may be performed. There are no particular limitations on the sterilization method, but examples include UHT sterilization, retort sterilization, and Joule sterilization. UHT sterilization can be performed by direct heating methods such as steam injection, in which steam is blown directly into the composition, or steam infusion, in which the composition is heated by injecting steam into the composition; indirect heating methods using surface heat exchangers such as plates or tubes, and the like, and can be performed by methods known per se, for example, a plate-type sterilizer can be used.

[0128] [Uses of the oil-in-water emulsion composition] The oil-in-water emulsion composition can be used for pharmaceuticals, cosmetics, foods, feeds, diagnostic agents, carriers for drug delivery systems (DDS), detergents, coating agents, surface treatment agents, toiletries, personal care products, etc. For example, it can be used for oral ingestion or transdermal absorption. It can also be used as a production intermediate thereof.

[0129] That is, the oil-in-water emulsion composition of the present invention may be an oil-in-water emulsion composition for food, an oil-in-water emulsion composition for cosmetic use, or an oil-in-water emulsion composition for pharmaceutical use, may be a food-grade, cosmetic-grade, or pharmaceutical-grade oil-in-water emulsion composition, or may be a food, cosmetic, or pharmaceutical product containing the oil-in-water emulsion composition. It is also possible to provide the oil-in-water emulsion composition itself as a food, cosmetic, or pharmaceutical product (a pharmaceutical product containing an active pharmaceutical ingredient).

[0130] In one embodiment, any of an oil-in-water emulsion composition, a food-grade oil-in-water emulsion composition, or a food-grade oil-in-water emulsion composition can be used in the production of food. By appropriately combining these compositions with other food production raw materials and / or food production preparations (intermediates), mixing and / or processing (including high-temperature treatment such as sterilization) the desired food can be produced, making it possible to provide foods containing the oil-in-water emulsion composition. By including the oil-in-water emulsion composition of the present invention, it is possible to achieve a taste quality with a suitable texture and flavor, as well as long-term storage stability. Specific examples of foods are described below.

[0131] In another embodiment, any of the oil-in-water emulsion compositions, cosmetic-grade oil-in-water emulsion compositions, and cosmetic-grade oil-in-water emulsion compositions can be used in the production of cosmetics. By appropriately combining and mixing and / or processing these compositions with other raw materials for cosmetic production and / or preparations for cosmetic production (including intermediates and / or active ingredients for cosmetics), desired cosmetics can be produced, making it possible to provide cosmetics containing the oil-in-water emulsion composition. 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.

[0132] In another embodiment, any of the oil-in-water emulsion compositions, pharmaceutical-grade oil-in-water emulsion compositions, and pharmaceutical-grade oil-in-water emulsion compositions can be used in the production of pharmaceuticals. These compositions can be appropriately combined with other raw materials for pharmaceutical production and / or pharmaceutical preparations (intermediates and / or active pharmaceutical ingredients, etc.) and mixed and / or processed (including high-temperature treatments such as sterilization) to produce the desired pharmaceuticals, making it possible to provide pharmaceuticals containing the oil-in-water emulsion compositions. By including the oil-in-water emulsion composition of the present invention, pharmaceuticals with excellent usability and a favorable texture, feel, or flavor (including masking of bitterness) can be obtained.

[0133] 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.

[0134] In particular, beverages, liquid foods, and other 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. Animal-derived food substitutes refer to emulsified compositions that can replace animal-derived foods such as milk in terms of taste, flavor, and physical properties. Examples of animal-derived food substitutes include milk substitutes, dairy-like foods and beverages, and condensed milk that do not contain animal-derived dairy products. Milk substitutes are also called plant-based milks. Examples of plant-based milks include almond beverages, oat beverages, coconut beverages, rice milk, cashew milk, hemp milk, pea milk, walnut beverages, soy milk, pistachio milk, barley milk, macadamia milk, and fruit juice beverages. The emulsified composition according to one embodiment of the present invention can also be used as an intermediate in the production of foods such as yogurt and ice cream. Examples of the 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 is one embodiment, can be suitably used for packaged beverages such as canned drinks, PET bottled drinks, paper-packaged drinks, and bottled drinks. Another example of an animal-derived food substitute is meat substitute. Meat substitute refers to a food product that does not contain animal-derived products or ingredients such as dairy products and is made from raw materials other than meat. Meat substitutes are also called meat substitutes, meat substitutes, mock meat, artificial meat, and imitation meat.

[0135] The pH of a product containing an oil-in-water emulsion composition (food, cosmetics, pharmaceuticals, or intermediates for producing them) may be set to a suitable range depending on the application and product. For example, when applied to food, it is sufficient as long as the pH is 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 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, particularly 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, it is possible to maintain better emulsion stability. By setting the pH in the above range, it is possible to maintain a good texture when eaten, in that the size of the dispersed phase (oil droplet diameter) can be suitably maintained.

[0136] The vegetable proteins, such as rice-derived proteins, and oils and fats disclosed in this specification are themselves publicly known, and can be produced or obtained by producing them according to publicly known methods or by purchasing commercially available products.

[0137] Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following description.

[0138] [Measurement Method] The measurement method is as follows.

[0139] (Particle size of solid particles or oil phase (oil droplets) which is the internal phase of emulsion) The particle size was measured as the volume average particle size (Dv) using a laser diffraction / scattering particle size distribution measuring device (MASTER SIZER 2000, Malvern). Distilled water was used as the dispersion medium for the measurement. Measurements were performed five times using a dispersion unit (Hydro2000SM, Malvern) at a stirring speed of 2000 rpm. The average value of the five measurements was taken as the volume average particle size (Dv) of the silkworm particles in a wet state (in an aqueous medium). The analysis was performed using a refractive index of 1.450.

[0140] (pH) Measurement was performed using a pH meter (CyberDcan pH110, EUTECH) or LAQUA PH / ION METER F-72 (manufactured by HORIBA, Ltd.).

[0141] (Microscopic Observation) Each solid particle was observed using a scanning electron microscope (SEM, Keyence, VE-8800). The protein aqueous dispersion or emulsion was observed using either an optical microscope (Motic BA200, Shimadzu Rika Co., Ltd.) equipped with a digital camera (Moticam 2000, Shimadzu Rika Co., Ltd.) or a polarizing microscope (Nikon ECLIPSEL V100NPOL, Nikon image integration software NIS-Elements Ver. 3.2).

[0142] (Zeta Potential Measurement) Using a zeta potential measurement device (Zetasizer Nano ZS, Malvern) equipped with an automatic titrator (MPT-2, Malvern), the zeta potential of each measurement sample at each pH was measured by electrophoresis. Specifically, the measurement sample was adjusted to pH 10 by adding an aqueous solution of sodium hydroxide (98%, Sigma-Aldrich), and hydrochloric acid (0.5 mol / L, Sigma-Aldrich) was gradually added from the initial pH to perform measurement. Using the same device, the hydrodynamic diameter of the measurement sample at each pH was measured by dynamic light scattering at a scattering angle of 173°.

[0143] A sample for measuring the zeta potential of the oil phase component (hardened palm oil) was prepared as follows: First, 1.5 ml of an isopropanol solution of the oil phase component (2 wt % oil phase component; hereafter, isopropanol will be abbreviated as IPA) was added to 110 g of water while stirring at 600 rpm using a magnetic stirrer (MAGNETIC STIRRER RS-1DN, AS ONE Corporation), and then stirring was continued at 250 rpm for one week to volatilize and remove the IPA, yielding an aqueous dispersion of the oil phase component.

[0144] (Measurement of surface tension and interfacial tension) Surface tension was measured by the Wilhelmy method using an automatic surface tensiometer (DY-300, AUTOMATIC SURFACE TENSIOMER, Kyowa Interface Science Co., Ltd.). The interfacial tension was measured using the ring method. The measurements were carried out at room temperature of 21 to 25°C.

[0145] (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 was used as a sample for free amino acid analysis.

[0146] 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.

[0147] Free amino acid analysis and hydrolyzed amino acid analysis were performed using the following equipment and under the following 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.

[0148] 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

[0149] (Acid Value, Saponification Value, and Slip Melting Point of Fats and Oils) Analytical tests for the acid value, saponification value, and slip melting point of fats and oils were performed according to the method described in Standard Methods for the Analysis of Fats, Oils, and Related Materials (edited by the Japan Oil Chemists' Society). Analysis of melting point was performed using a melting point measuring device (MP-J8, Yanaco Instrument Development Laboratory Co., Ltd.).

[0150] (Quantitative analysis of phospholipids) The following items were analyzed 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

[0151] [Materials Used] The raw materials used in the examples and their physical properties are as follows.

[0152] As the oil phase component, hydrogenated coconut oil (edible oil) or n-dodecane (organic solvent) was used. Hydrogenated coconut oil is solid at 25°C. The acid value of hydrogenated coconut oil is 0.47. The saponification value is 255. The slip melting point is 28.8°C. The melting point is in the range of 27.0 to 39.9°C.

[0153] The following rice-derived protein from a grass family plant was used as the solid particle: Oryza Protein-P70, a product of Oryza Oil & Fat Chemical Co., Ltd. [protein obtained from the seeds of the grass family (Oryza sativus Linne); hereinafter, this will be abbreviated as P70.] The amino acid score of P70 is 56. The contact angle of water with P70 is 69°.

[0154] Ion-exchanged water or demineralized water was used as water.

[0155] The zeta potential measurement results of the hardened palm oil aqueous dispersion are shown in Figure 1. The physical properties of other substances are also shown in Table 1 for reference.

[0156]

[0157] [Preparation of Aqueous Protein Dispersion] (Preparation Example 1) First, 95 parts by weight of water and 5 parts by weight of P70 (rice-derived protein) previously classified through a 45 μm sieve were dispensed into a container and stirred with a magnetic stirrer. This mixture was treated 10 times at 245 MPa using an ultra-high pressure homogenizer (manufactured by Sugino Machine Co., Ltd., Starburst Lab, using an oblique light impingement chamber) to obtain aqueous protein dispersion A1. Next, this aqueous protein dispersion was dispensed into a container and heated at 121°C and 0.12 MPa for 30 minutes using an autoclave (Hiclave HG-80, manufactured by Hirayama Seisakusho Co., Ltd.), followed by cooling to room temperature to obtain aqueous protein dispersion A2.

[0158] Preparation Example 2 Aqueous protein dispersions B1 and B2 were obtained in the same manner as in Preparation Example 1, except that after autoclaving, an appropriate amount of aqueous citric acid solution was added to adjust the pH to 4.

[0159] (Preparation Example 3) The protein aqueous dispersion A2 obtained in Preparation Example 1 was centrifuged at 15,000 rpm for 10 minutes using a centrifuge (CF16RX II, HITACHI) under brake-free conditions, and the supernatant was separated and replaced with ion-exchanged water. The supernatant was then redispersed in a Branson tabletop ultrasonic cleaner (Branson, M2800-J). This centrifugal washing procedure was repeated a total of 20 times to obtain protein aqueous dispersion C. The solids concentration, determined by measuring the dry weight of the protein aqueous dispersion, was 2.94 wt%. The supernatants removed after the first, tenth, and twentieth centrifugal washings are referred to as supernatants C-1, C-10, and C-20, respectively.

[0160] (Preparation Example 4) A protein aqueous dispersion D (solids concentration: 2.94 wt %) was obtained in the same manner as in Preparation Example 3, except that after 20 cycles of centrifugal washing, an appropriate amount of aqueous citric acid solution was added to adjust the pH to 4.

[0161] (Preparation Example 5) A protein aqueous dispersion E (solids concentration: 2.33 wt %) was obtained in the same manner as in Preparation Example 3, except that centrifugal washing was carried out 30 times. The supernatant removed after the 30th centrifugal washing is referred to as supernatant E-30.

[0162] (Preparation Example 6) A protein aqueous dispersion F (solids concentration: 2.33 wt %) was obtained by operating in the same manner as in Preparation Example 3, except that centrifugal washing was performed 30 times and that the pH was adjusted to 4 by adding an appropriate amount of an aqueous citric acid solution after the centrifugal washing.

[0163] (Preparation Example 7) The protein aqueous dispersion A2 obtained in Preparation Example 1 was subjected to dialysis to obtain a protein aqueous dispersion G (solids concentration: 5.35 wt %). The dialysate outside the dialysis membrane was exchanged with water three times. The dialysate fractions collected in the first, second, and third exchanges are referred to as dialysates A2-1, A2-2, and A2-3. The dialysis membrane used had a MWCO of 1000 kDa and a size of 10 × 16 mm.

[0164] (Preparation Example 8) A protein aqueous dispersion H (solids concentration: 5.35 wt %) was obtained in the same manner as in Preparation Example 7, except that the pH was adjusted to 4 by adding an appropriate amount of aqueous citric acid solution after dialysis.

[0165] Preparation Example 9: 95 parts by weight of water and 5 parts by weight of P-70 (rice-derived protein) that had been previously classified using a sieve with an opening diameter of 45 μm were dispensed into a container and stirred. This mixture was subjected to 10 passes at 245 MPa using an ultra-high pressure homogenizer (manufactured by Sugino Machine Corporation, Starburst Lab, using an oblique light impingement chamber), and then an aqueous citric acid solution was added to adjust the pH to 4, thereby obtaining an aqueous protein dispersion I.

[0166] (Preparation Example 10) Aqueous protein dispersion J was obtained in the same manner as in Preparation Example 9, except that the pH was adjusted to 4 by adding an appropriate amount of aqueous hydrochloric acid after treatment with the Starburst Lab.

[0167] Preparation Example 11: 95 parts by weight of water and 5 parts by weight of P-70 (rice-derived protein) that had been previously classified using a sieve with an opening diameter of 45 μm were dispensed into a container and stirred. This mixture was subjected to 10 passes at 245 MPa using an ultra-high pressure homogenizer (manufactured by Sugino Machine Corporation, Starburst Lab, using an oblique light impingement chamber) to obtain a protein aqueous dispersion K (solid concentration: 4.26% by weight).

[0168] Preparation Example 12 An aqueous protein dispersion L was obtained in the same manner as in Preparation Example 11.

[0169] (Preparation Example 13) A protein aqueous dispersion M was obtained in the same manner as in Preparation Example 11. This protein aqueous dispersion M was subjected to the centrifugal washing procedure described in Preparation Example 2 three times to obtain a protein aqueous dispersion M-3. The supernatant obtained by separating the supernatant from the first centrifugal washing procedure is referred to as supernatant M-1 (sometimes referred to as protein aqueous dispersion M1).

[0170] (Preparation Example 14) 90 parts by weight of demineralized water and 10 parts by weight of P70 were dispensed into a container and stirred. After this, the mixture was allowed to stand, and the supernatant was separated, avoiding the sediment (solids concentration calculated from the dry weight of the supernatant: 0.65% by weight). This supernatant was mixed with demineralized water and adjusted to 0.40% by weight as shown in Table 2, to obtain supernatant N-1 (sometimes referred to as protein aqueous dispersion N-1).

[0171]

[0172] [Preparation of oil-in-water emulsion composition]

[0173] (Example 1) Protein aqueous dispersion C and hardened coconut oil were dispensed into containers at a weight ratio of 8:2 and then allowed to stand for 1 hour in a thermostatic bath at 65°C. The mixture was then stirred at 12,000 rpm for 2 minutes using a homogenizer in a water bath at 60°C, thereby obtaining an oil-in-water emulsion composition C.

[0174] Example 2 An oil-in-water emulsion composition D was obtained in the same manner as in Example 1, except that the protein aqueous dispersion D was used instead of the protein aqueous dispersion C.

[0175] Example 3 An oil-in-water emulsion composition E was obtained in the same manner as in Example 1, except that the protein aqueous dispersion E was used instead of the protein aqueous dispersion C.

[0176] Example 4 An oil-in-water emulsion composition F was obtained in the same manner as in Example 1, except that the protein aqueous dispersion F was used instead of the protein aqueous dispersion C.

[0177] Example 5 An oil-in-water emulsion composition G was obtained in the same manner as in Example 1, except that the protein aqueous dispersion G was used instead of the protein aqueous dispersion C.

[0178] Example 6 An oil-in-water emulsion composition H was obtained in the same manner as in Example 1, except that the protein aqueous dispersion H was used instead of the protein aqueous dispersion C.

[0179] Comparative Example 1 An oil-in-water emulsion composition N was obtained in the same manner as in Example 1, except that ion-exchanged water was used instead of the aqueous protein dispersion C.

[0180] Comparative Example 2 Protein aqueous dispersion K and n-dodecane were dispensed into containers at a weight ratio of 8:2, and then the mixture was hand-shaken at room temperature for 2 minutes to obtain an oil-in-water emulsion composition O.

[0181] Comparative Example 3 An oil-in-water emulsion composition A was obtained in the same manner as in Example 1, except that the aqueous protein dispersion A2 was used instead of the aqueous protein dispersion C.

[0182] Comparative Example 4 An oil-in-water emulsion composition B was obtained in the same manner as in Example 1, except that the aqueous protein dispersion B2 was used instead of the aqueous protein dispersion C.

[0183] Comparative Example 5 An oil-in-water emulsion composition L was obtained in the same manner as in Example 1, except that the aqueous protein dispersion K was used instead of the aqueous protein dispersion C and stirring was performed by hand shaking.

[0184] The composition ratios of the examples and comparative examples are shown in Tables 3 and 4.

[0185]

[0186]

[0187] [Evaluation of Aqueous Protein Dispersions and Their Preparation Processes] (Evaluation of Aqueous Protein Dispersions and Their Preparation Processes) Table 5 shows the results of measuring the surface tension of the supernatants (supernatants C-1, C-10, C-20, E-30) during centrifugal washing in the preparation steps of aqueous protein dispersions C, D, E, and F according to Examples 1 to 4.

[0188]

[0189] The results shown in Table 5 indicate that the surface tension of the supernatant increased with an increase in the number of centrifugal washes, indicating that repeated washing reduced the amount of water-soluble surface-active component (amphiphile) eluted into the washing solvent (water). These results suggest that it was possible to prepare aqueous protein dispersions (specifically, aqueous protein dispersions C, D, E, and F) from which at least a portion of the water-soluble surface-active component had been removed by the washing procedure.

[0190] Table 6 shows the results of measuring the surface tension of the dialysate (liquid on the outer side of the dialysis membrane) in the dialysis step in the preparation process of aqueous protein dispersions G and H in Examples 5 and 6.

[0191]

[0192] The results in Table 6 show that the surface tension of the dialysate increases with an increase in the number of dialysis cycles, and the amount of water-soluble surfactant (amphiphile) eluted into the solvent (water) outside the dialysis membrane decreases. These results indicate that it is possible to prepare aqueous protein dispersions (specifically, aqueous protein dispersions G and H) from which at least a portion of the water-soluble surfactant has been removed by the dialysis procedure.

[0193] (Evaluation of Particle Size and Shape of Protein in Aqueous Protein Dispersions) Electron microscope images of the water-removed powders of P70 (rice protein), protein aqueous dispersion A2, and protein aqueous dispersion E used in the Examples and / or Comparative Examples are shown in Figures 2, 3, and 4, respectively. Furthermore, a microscope image of protein aqueous dispersion K used in Comparative Example 5 is shown in Figure 5. Measurement results of particle size distribution for the aqueous dispersion of P70 (raw rice protein), protein aqueous dispersion M, and protein aqueous dispersion M-3 are shown in Figures 6, 7, and 8. Average particle size Dv values ​​are also shown.

[0194] [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

[0195] (Analysis of surfactant components contained in raw material protein (P70)) The results of quantitative analysis of phospholipids contained in P70 (rice protein) used in the Examples and Comparative Examples are shown in Table 7. This table shows that the raw material protein (P70) contains 1.62% by mass of phospholipids (PC, PI, PS, LPC, PE, APE, LPE, PG, PA). It also shows that the raw material protein (P70) contains 1.54% by mass of lysolecithin (LPC, LPE).

[0196]

[0197] From the evaluation of the protein amount contained in the raw material protein (P70) and the analysis results of the surface-active components contained in the raw material protein, the weight ratio of phospholipids (amphiphiles) to the total solid content of the raw material protein (P70) and the weight ratio of the phospholipid (amphiphile) content to the total amount of protein (protein contained in P70) were found to be the following values: (phospholipid content) / (total amount of P70): 0.0162 (phospholipid content) / (protein content): 0.021

[0198] When the entire amount of raw material protein (P70) is subjected to emulsification, the weight ratios of each component in the total amount of emulsion composition will be the values ​​described above, unless phospholipids or proteins derived from other ingredients are added. It is presumed that a portion of each substance shown in Table 7 will be eluted or permeated into water during the centrifugal washing or dialysis described above, thereby enabling the preparation of solid particles (materials to be subjected to emulsification) with a minimal content of surface-active components (amphiphiles). In this case, it can be easily predicted that the phospholipid content relative to the total amount of raw material protein, the weight ratio of the phospholipid content relative to the total amount of raw material protein, and the weight ratio of the phospholipid content relative to the protein content in the raw material protein will be lower than the values ​​described above. It can be seen that when this is subjected to emulsification, the weight ratios of each component in the total amount of emulsion composition will also be lower than the values ​​described above, unless phospholipids or proteins derived from other ingredients are added.

[0199] [Evaluation of Oil-in-Water Emulsion Compositions] (Evaluation of Emulsification Ability) Table 8 shows whether or not the above-mentioned Examples and Comparative Examples could be emulsified immediately after stirring.

[0200]

[0201] (Evaluation of emulsion stability) 1. In emulsion stability comparative example 2 (emulsion composition O), n-dodecane, an organic solvent, was used as the oil phase component. Because n-dodecane is a liquid at room temperature, stirring at room temperature was possible. Visual observation immediately after stirring by handshaking at room temperature showed that the entire mixture was cloudy and emulsifiable, but 5 minutes after stirring was completed, oil phase separation was visually confirmed on the liquid surface, indicating extremely low emulsion stability. It is presumed that the solid particles in the protein aqueous dispersion of this embodiment are not sufficiently hydrophobic to be adsorbed to the interface between n-dodecane and water for stabilization.

[0202] On the other hand, when we look at emulsion composition L according to Comparative Example 5, which also uses handshake stirring conditions, it becomes stirrable by heating to 65°C to turn the hardened palm oil into a liquid state. Emulsion composition L is emulsifiable, and even when a container containing it was immersed in room-temperature water for one minute or more and allowed to cool, no decrease in fluidity due to coalescence or separation of the oil phase was observed, and microscopic observation at room temperature was possible. The microscopic image is shown in Figure 9. Figure 9 confirms the adsorption of solid particles to the oil-water interface. In comparison, in all of the Examples of the present application, the solid particles were more tightly adsorbed to the oil-water interface. The emulsion composition of the present invention thus forms a structure in which at least a portion of the solid particles are more tightly adsorbed to the oil-water interface, thereby maintaining a more stable emulsified state regardless of the size of the oil droplets.

[0203] 2. Temperature-lowering stability of emulsion compositions For the emulsion compositions prepared in Examples 1 to 6, Comparative Example 1, and Comparative Examples 3 to 5, the containers were allowed to cool by immersing them in a room temperature water bath for at least 1 minute. After a further 5 minutes or more had elapsed, the state inside the container (fluidity of the emulsion composition) was visually confirmed when the container was tilted or shaken, and the temperature-lowering stability of the emulsion composition was evaluated according to the following criteria. The results are shown in Table 8.

[0204] A: Liquid. B: No liquidity.

[0205] Table 8 shows that the emulsion compositions of the Examples have excellent temperature-lowering stability. On the other hand, for emulsion composition N according to Comparative Example 1, which does not contain solid particles, the liquid did not flow after cooling, and the stability during cooling was poor. From the results of appearance observation, it is presumed that after emulsification, the oil droplets coalesced or aggregated, or the oil phase separated, and then, in the process of cooling from 60°C to room temperature (25°C), the oil crystallized (changed state from liquid to solid), resulting in a shape that appeared to cap the top of the liquid and causing a loss of fluidity.

[0206] 3. Evaluation of the degree of interfacial adsorption of solid particles For the Examples and Comparative Examples, the success or failure of emulsification and the degree of interfacial adsorption of solid particles, which is related to the stability of the emulsion, are shown in Table 8. Microscopic images of the prepared emulsion compositions are also shown in Figures 10 to 18. From these microscopic images, the degree of adsorption of solid particles (rice protein) to the oil-water interface was evaluated using the following five-point scale, and the results are shown in Table 8. Since emulsion composition N had low stability when cooled from 60°C to room temperature, the emulsion was quickly observed immediately after stirring, and the results are shown for reference.

[0207] N: No adsorption of solid particles to the oil-water interface. +: It is unclear whether or not solid particles are adsorbed to the oil-water interface. ++: Although some adsorption of solid particles to the oil-water interface is confirmed (there are irregularities on the outer edge), the state of adsorption is sparse. +++: Adsorption of solid particles to the oil-water interface is confirmed (there are irregularities on the outer edge), and the state of adsorption is dense. ++++: Adsorption of solid particles to the oil-water interface is confirmed (including irregularities on the outer edge), and the state of adsorption is so dense that light transmittance is reduced.

[0208] As shown in Table 8, in cases where interfacial adsorption of solid particles was confirmed by microscopic observation, an O / W emulsion with good temperature-lowering stability was formed. Furthermore, the denser the degree of interfacial adsorption of solid particles, the more physically inhibited contact between oil droplets is, which is thought to reduce the likelihood of coalescence of oil droplets or aggregation via crystallized portions of oil droplets, which can lead to destabilization of the emulsion composition. This makes it possible to provide an emulsion composition with excellent stability that can be stored for long periods and subjected to heat treatment at high temperatures.

[0209] In particular, in an emulsion composition from which at least a portion of the amphiphilic substance (a water-soluble surface-active component and / or a water-dispersible surface-active component) has been removed, the interfacial adsorption of the solid particles is in a denser state. From this result, it is presumed that an emulsion composition with superior stability can be provided by limiting the amount of the amphiphilic substance (a water-soluble surface-active component and / or a water-dispersible surface-active component) to a specific amount.

[0210] According to the present invention, an emulsion composition having excellent emulsion stability can be provided.

Claims

1. An oil-in-water emulsion composition comprising water, oil, and solid particles, wherein the solid particles are present at the interface between the water and the oil, at least a portion of the solid particles are vegetable proteins, and the content ratio of the amphiphilic substance to the vegetable protein is less than 0.

021.

2. The oil-in-water emulsion composition according to claim 1, wherein the vegetable protein is a protein derived from a grass family plant.

3. The oil-in-water emulsion composition according to claim 1, wherein the amphiphilic substance is a plant-derived amphiphilic substance.

4. The oil-in-water emulsion composition of claim 1, wherein the amphiphile is an ionic amphiphile.

5. The oil-in-water emulsion composition of claim 4, wherein the ionic amphiphile is a phospholipid.

6. The oil-in-water emulsion composition of claim 4, wherein the ionic amphiphile is lysolecithin.

7. The oil-in-water emulsion composition according to claim 1, wherein the pH of the aqueous phase is 3.0 to 7.

5.

8. A method for producing an oil-in-water emulsion composition comprising water, oil, and solid particles, the solid particles being present at the interface between the water and the oil, wherein the solid particles are vegetable proteins obtained by removing at least a portion of an amphiphilic substance from a vegetable protein raw material.

9. The method for producing an oil-in-water emulsion composition according to claim 8, wherein the vegetable protein is a protein derived from a grass family plant.

10. The method for producing an oil-in-water emulsion composition according to claim 8, wherein the amphiphilic substance is an ionic amphiphilic substance.

11. The method for producing an oil-in-water emulsion composition according to claim 10, wherein the ionic amphiphilic substance is a phospholipid.

12. The method for producing an oil-in-water emulsion composition according to claim 10, wherein the ionic amphiphilic substance is lysolecithin.

13. The method for producing an oil-in-water emulsion composition according to claim 8, further comprising adjusting the pH of the protein aqueous dispersion obtained by stirring the vegetable protein and the water to a range of 3.0 to 7.5, and then stirring the protein aqueous dispersion with the oil.

14. A method for producing an oil-in-water emulsion composition comprising water, oil, and solid particles, the solid particles being present at the interface between the water and the oil, wherein the solid particles are made of vegetable protein having a plant-derived amphiphilic substance content of less than 1.62% by mass.

15. The method for producing an oil-in-water emulsion composition according to claim 14, wherein the vegetable protein is a protein derived from a grass family plant.

16. The method for producing an oil-in-water emulsion composition according to claim 14, wherein the amphiphilic substance is an ionic amphiphilic substance.

17. The method for producing an oil-in-water emulsion composition according to claim 16, wherein the ionic amphiphilic substance is a phospholipid.

18. The method for producing an oil-in-water emulsion composition according to claim 16, wherein the ionic amphiphile is lysolecithin.

19. The method for producing an oil-in-water emulsion composition according to claim 14, further comprising adjusting the pH of the protein aqueous dispersion obtained by stirring the vegetable protein and the water to a range of 3.0 to 7.5, and then stirring the protein aqueous dispersion with the oil.

20. A microparticulate emulsifier having a plant-derived amphiphilic substance to plant protein content ratio of less than 0.

021.

21. The microparticulate emulsion of claim 20, wherein the amphiphile is an ionic amphiphile.

22. The microparticulate emulsion of claim 21, wherein the ionic amphiphile is a phospholipid.

23. The microparticulate emulsifier of claim 21, wherein the ionic amphiphile is lysolecithin.

24. A food product comprising the oil-in-water emulsion composition according to any one of claims 1 to 7.

25. A milk replacer comprising the oil-in-water emulsion composition according to any one of claims 1 to 7.

26. A pharmaceutical product comprising the oil-in-water emulsion composition according to any one of claims 1 to 7.

27. A cosmetic comprising the oil-in-water emulsion composition according to any one of claims 1 to 7.

28. A personal care product comprising the oil-in-water emulsion composition of any one of claims 1 to 7.

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