Particles each having coating layer, and method for producing same

Abstract

Particles each comprising a liquid inclusion and a coating layer that coats the inclusion, wherein the coating layer includes a gel layer that contains a hydrogel and an oil / fat composition that adheres to the gel layer.

Description

Particles with a coating layer and method for producing the same

[0001] The present invention relates to particles with a coating layer and a method for producing the same.

[0002] In foods, pharmaceuticals, etc., a technique is known in which a taste component or an active ingredient is coated with another component to form a particulate shape. For example, Patent Document 1 describes a coated granulated product in which a taste component is coated with a poorly water-soluble component, and a technique for making it difficult to feel unpleasant tastes such as bitterness and spiciness in the oral cavity is described.

[0003] Japanese Unexamined Patent Application Publication No. 2012 - 87064

[0004] Suzuki et al., "Influence of Manipulation Factors on Particle Characteristics and Dispersion Stability of Chitosan - Oleic Acid Composite Fine Particles", The 50th Autumn Meeting of the Chemical Engineering Society of Japan (2018)

[0005] The coated granulated product described in Patent Document 1 is intended to make it difficult to feel unpleasant tastes in the oral cavity. On the other hand, techniques have been studied to make it possible to feel a sufficient taste even with a small amount of taste components by unevenly distributing taste components such as saccharides and salts in the form of particles in foods. Unevenly distributing taste components in foods leads to suppression of excessive intake of saccharides, salts, etc., and is thus useful. Also, in the case of highly water - soluble aquatic feed, it is possible to prevent diffusion and dispersion of feed components in water.

[0006] On the other hand, in such techniques, the problem of temporal diffusion of the unevenly distributed taste components during storage (the time from after production until the effect is exerted) can arise. For example, even if taste components are unevenly distributed in foods in the form of particles, the encapsulated components leak and diffuse from the particles over time during storage, and eventually change to a uniform distribution. In particular, when trying to unevenly distribute liquid components such as sugar solution and brine in liquid foods, leakage and diffusion of taste components are more likely to occur, and it is difficult to maintain the state where taste components are unevenly distributed in the food for a long time.

[0007] An object of the present invention is to provide particles in which a liquid inclusion is coated with a coating layer, and leakage of the coated inclusion to the outside of the particles is suppressed.

[0008] The inventors of the present invention have discovered that by attaching an oil and fat composition to a gel layer containing hydrogel, and using this as a coating layer to coat encapsulated components such as flavoring components, it is possible to prepare particles in which encapsulated components are less likely to leak out over time, thus completing the present invention.

[0009] The present invention provides, for example, the following [1] to

[14] : [1] A particle comprising a liquid encapsulant and a coating layer covering the encapsulant, wherein the coating layer comprises a gel layer containing a hydrogel and an oil and fat composition adhering to the gel layer. [2] The particle according to [1], wherein the hydrogel comprises a polysaccharide-derived gel. [3] The particle according to [2], wherein the polysaccharide-derived gel comprises an alginate gel. [4] The particle according to any one of [1] to [3], wherein the oil and fat composition contains an oil and fat and an emulsifier. [5] The particle according to any one of [1] to [4], wherein the gel layer further comprises lambda-carrageenan. [6] The particle according to any one of [1] to [5], further comprising an inner layer containing a hydrogel between the encapsulant and the coating layer. [7] The particle according to [6], wherein the hydrogel contained in the inner layer comprises an alginate gel. [8] The particle according to any one of [1] to [7], further comprising an outer layer containing a hydrogel covering the coating layer. [9] Particles according to any one of [1] to [8], wherein the breaking strength is 10 kPa or less.

[10] Particles according to any one of [1] to [9], which are a food composition or a feed composition.

[11] A method for producing particles comprising a liquid encapsulant and a coating layer covering the encapsulant, comprising a gel layer coating step of covering the encapsulant with a gel layer containing a hydrogel, and an oil and fat adhesion step of contacting the gel layer with an emulsion of oil and fat.

[12] A method for producing particles comprising a liquid encapsulant, a coating layer covering the encapsulant and an inner layer provided between the encapsulant and the coating layer, comprising an inner layer coating step of covering the encapsulant with an inner layer containing a first hydrogel, a gel layer coating step of covering the inner layer with a gel layer containing a second hydrogel, and an oil and fat adhesion step of contacting the gel layer with an emulsion of oil and fat.

[13] The manufacturing method according to

[11] or

[12] , wherein the gel layer coating step includes positively or negatively charging the gel layer, and the oil and grease application step includes contacting the gel layer with an emulsion having a charge opposite to the charge it has.

[14] A method for producing particles comprising a liquid encapsulant and a coating layer covering the encapsulant, comprising the steps of: laminating at least an emulsion of oil and fat, a solution containing a hydrogel precursor, and the encapsulant in this order on a support sheet containing a hydrogel, gelling the hydrogel precursor to form a coating layer including a gel layer to which the oil and fat composition is attached; and forming the particles using a laminate in which the layers of the support sheet, the coating layer, and the encapsulant are laminated.

[0010] According to the present invention, it is possible to provide particles in which leakage of coated encapsulants to the outside of the particle is suppressed.

[0011] This is a schematic cross-sectional view of the particles according to the first embodiment. This is a schematic cross-sectional view of the particles according to the second embodiment. This is a schematic cross-sectional view of the particles according to the third embodiment. This is a microscopic image showing the structure of the particles according to Example 1. This is a graph showing the results of the inclusion leakage confirmation test. This is a graph showing the fracture strength measurement of the particles according to Example 1 and fish eggs as a comparison.

[0012] The embodiments for carrying out the present invention will be described in detail below. However, the present invention is not limited to the following embodiments.

[0013] In the numerical ranges described stepwise in this specification, the upper or lower limit of one step in the numerical range can be arbitrarily combined with the upper or lower limit of another step in the numerical range. In the numerical ranges described in this specification, the upper or lower limit of that numerical range may be replaced with the values ​​shown in the examples. Unless otherwise specified, the components or materials exemplified in this specification can be used individually or in combination of two or more.

[0014] In this specification, "particle" refers to an individual in which an inclusion is covered with a continuous coating layer, and its overall shape is not particularly limited. Particles are not limited to spherical or nearly spherical shapes, but include flattened shapes that can be formed depending on manufacturing conditions, such as oblate spheroids (spheroidal shapes) and lens-shaped shapes with a thicker center and thinner edges (for example, shapes like those shown in Figure 3, described later).

[0015] The particles according to this embodiment are particles comprising a liquid encapsulant and a coating layer that covers the encapsulant, wherein the coating layer comprises a gel layer containing a hydrogel and an oily composition adhering to the gel layer.

[0016] The particles according to this embodiment, having the above configuration, can suppress the leakage of encapsulated substances from the particles to the outside. This is thought to be partly because, as a result of the oil composition adhering to the hydrogel, at least a portion of the gel layer is covered with the oil composition, making it difficult for the encapsulated substances to come into contact with components outside the particles. Therefore, for example, if particles containing flavor components as encapsulated substances are prepared, it becomes possible to unevenly distribute the flavor components in food, and to maintain this unevenly distributed state for a long period of time.

[0017] Furthermore, because the particles of this embodiment have the above-described configuration, it is possible to easily release the encapsulated substances within the particles by impacting them or applying pressure. For example, when particles containing flavor components are prepared and unevenly distributed in food, chewing the food containing the particles will release the flavor components within the particles, allowing them to diffuse into the oral cavity. In other words, the particles according to this embodiment have the seemingly contradictory effects of suppressing the leakage of encapsulated substances outside the particles while simultaneously allowing for easy and sufficient release of encapsulated substances when the intention is to release them outside the particles.

[0018] <First Embodiment> Figure 1 is a schematic cross-sectional view showing particles according to the first embodiment. The particles 10 shown in Figure 1 comprise a liquid encapsulant 1 and a coating layer 2 that covers the encapsulant 1. The coating layer 2 comprises a gel layer 3 containing a hydrogel and an oil and fat composition 4 that adheres to the gel layer 3.

[0019] Inclusion 1 can be any liquid substance or composition. For example, the inclusion can be a pharmaceutical or quasi-drug that exerts activity when released from the particles in the oral cavity, a food or food additive that affects human taste receptors and provides a taste, a feed composition for animals or aquatic organisms, an enzyme solution, a component that serves as a substrate for an enzyme, a reactive protein such as an antibody, or any other substance that exhibits some reaction and produces an effect when released from the particles, and solutions thereof. Note that "liquid" in the context of a liquid inclusion means that it is fluid at room temperature (e.g., 20°C).

[0020] Among the contents 1, one example of a food-acceptable component is a flavor component. A flavor component is a component that gives a taste to food, and examples include sweet components such as sugars, sweeteners, and honey; salty components such as salt, soy sauce, and miso; sour components such as citric acid, malic acid, and acetic acid; and water-soluble pungent components such as allyl isothiocyanate. In this embodiment, these flavor components may be used as they are, or they may be used as a composition (sugar solution, saline solution, etc.) in which they are dissolved in a solvent such as water.

[0021] The amount of inclusion 1 contained in particle 10 may be 0.1 mg or more, 1 mg or more, 10 mg or more, 100 mg or less, or 50 mg or less per particle.

[0022] The gel layer 3 constituting the coating layer 2 contains at least a hydrogel. In this specification, a hydrogel is a substance in which a three-dimensional network structure formed by a polymer swells when it contains water. Examples of hydrogels include polysaccharide-derived gels such as alginate gel, carrageenan gel, agar gel, xanthan gum gel, gellan gum gel, guar gum gel, and pectin gel; gels derived from egg white protein, soy protein, or milk protein; gelatin gel, collagen gel, and other protein-derived gels. The gel layer 3 may contain one or more of these hydrogels. In the particles 10 according to this embodiment, it is preferable that the hydrogel contains a polysaccharide-derived gel.

[0023] The polysaccharide-derived gel preferably includes alginate gel or carrageenan gel. This facilitates the adhesion of the oil composition 4 to the hydrogel, and allows the encapsulated substance 1 to be released from the particle with only slight impact or pressure when desired. The gel layer 3 may contain only alginate gel as the hydrogel, or only carrageenan gel.

[0024] The alginate gel may be a reaction product (crosslinked product) of alginic acid or a salt thereof with cations such as calcium ions, magnesium ions, or barium ions. The alginic acid salt may be potassium alginate, sodium alginate, ammonium alginate, etc., and sodium alginate is preferred. The alginate gel is more preferably a reaction product of sodium alginate and calcium ions.

[0025] Carrageenan gel may be a reaction product (crosslinked product) of carrageenan (kappa-carrageenan, iota-carrageenan) and cations such as potassium ions and calcium ions.

[0026] The gel layer 3 may contain components other than hydrogel. In addition to hydrogel, the gel layer 3 may further contain lambda-carrageenan. Lambda-carrageenan may be included in the gel layer 3 after forming crosslinks through reaction with cations, or it may be included in the hydrogel without forming crosslinks. In one embodiment, the gel layer 3 may contain alginate gel as the hydrogel and further contain lambda-carrageenan. When the gel layer 3 contains lambda-carrageenan, the sulfate groups of lambda-carrageenan cause the surface of the gel layer 3 to become negatively charged, making it possible to more effectively adhere the oil composition 4 to the gel layer 3 through interionic interactions.

[0027] The thickness (film thickness) of the gel layer 3 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more, from the viewpoint of maintaining the structure of the particles 10, and preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.6 mm or less, from the viewpoint of facilitating the release of the encapsulated material 1.

[0028] The oil and fat composition 4 is attached to the gel layer 3. The oil and fat composition 4 may be in the form of an oil film and may cover part or all of the gel layer 3, or it may be attached to the gel layer 3 by being held within the gel layer 3. When the oil and fat composition 4 is held in the gel layer 3, it can be held in the gel layer 3 by, for example, penetrating into the network structure of the hydrogel.

[0029] The oil and fat composition 4 contains at least oil and fat, and may be oil and fat itself, or may contain oil and fat and other components. Examples of oil and fat include vegetable oils such as soybean oil, rapeseed oil (canola oil), corn oil, rice oil, safflower oil, sunflower oil, cottonseed oil, olive oil, and grapeseed oil, or refined oils thereof (salad oil, refined oil), squalane, squalene, and essential oils.

[0030] The fat and oil composition 4 may contain an emulsifier in addition to fats and oils. Any material acceptable for pharmaceuticals, quasi-drugs, or food products can be used as the emulsifier without limitation. Preferably, the emulsifier can impart a positive or negative charge to the fat and oil composition 4, and more specifically, an charge opposite to the charge of the gel layer 3. This makes it easier for the fat and oil composition 4 to adhere to the gel layer 3. An example of such an emulsifier is the chitosan-fatty acid complex disclosed in Non-Patent Literature 1. The chitosan-fatty acid complex is an emulsifier that is positively charged by the amino group of chitosan, and when used, the fat and oil composition 4 can also be positively charged.

[0031] If the oil and fat composition 4 contains an emulsifier, the oil and fat composition 4 may be in the form of emulsified particles. The oil and fat composition 4 in the form of emulsified particles can adhere to the gel layer 3 by penetrating and adhering to the network structure of the hydrogel. The oil and fat composition 4 containing an emulsifier may coat the gel layer 3 with an oil film formed as a result of the coalescence of the emulsified particles. That is, the oil and fat composition 4 may contain emulsified particles containing oil and fat and an emulsifier, or it may be an oil film containing oil and fat and an emulsifier.

[0032] The thickness of the coating layer 2 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more, from the viewpoint of maintaining the structure of the particles 10, and preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.6 mm or less, from the viewpoint of facilitating the release of the encapsulated material 1.

[0033] Next, a method for producing the particles 10 according to this embodiment will be described. The method for producing the particles 10 according to this embodiment comprises a gel layer coating step of coating a liquid encapsulant 1 with a gel layer 3 containing hydrogel, and an oil and fat attachment step of bringing an oil and fat emulsion into contact with the gel layer 3.

[0034] In one embodiment, the gel layer coating step includes bringing a liquid containing a liquid encapsulant 1 and, if necessary, a substance that gels the hydrogel precursor (for example, a cation described later) into contact with the hydrogel precursor to gel the hydrogel precursor, thereby coating the encapsulant 1 with a gel layer 3 containing hydrogel.

[0035] In this case, first, a solution containing the hydrogel precursor and a solution containing encapsulation 1 and, if necessary, a substance to gel the hydrogel precursor are prepared. The solution containing the hydrogel precursor contains the hydrogel precursor, water, and, if necessary, other components.

[0036] A hydrogel precursor is a substance from which a hydrogel can be obtained by gelation. Examples of hydrogel precursors include alginic acid or its salts, polysaccharides such as carrageenan and agar, and proteins such as gelatin and collagen before gelation. The hydrogel precursor is preferably a polysaccharide, and more preferably alginic acid or its salt. Specific examples of alginic acid salts are as described above.

[0037] In a solution containing a hydrogel precursor, the concentration of the hydrogel precursor may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and may be 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total amount of the solution containing the hydrogel precursor.

[0038] The solution containing the hydrogel precursor may also contain lambda-carrageenan as another component. If the solution containing the hydrogel precursor contains lambda-carrageenan, the concentration of lambda-carrageenan may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total amount of the solution containing the hydrogel precursor.

[0039] The solution containing the inclusion 1 may be the liquid inclusion 1 itself, or it may be a solution obtained by mixing the liquid inclusion 1 with other components as needed.

[0040] The solution containing encapsulation 1 may also contain other components, such as a substance for gelling the hydrogel precursor. Examples of substances for gelling the hydrogel precursor include salts that provide cations in the solution. The salt that provides cations in the solution can be appropriately selected depending on the type of hydrogel precursor used.

[0041] For example, when the hydrogel precursor is alginic acid or a salt thereof, salts that provide cations in solution include calcium salts such as calcium chloride, calcium lactate, calcium carbonate, calcium acetate, and calcium phosphate; magnesium salts such as magnesium chloride; and barium salts such as barium chloride. Alternatively, when the hydrogel precursor is kappa-carrageenan, salts that provide cations in solution include potassium salts such as potassium chloride and potassium citrate. When the hydrogel precursor is alginic acid or a salt thereof, the salt that provides cations in solution is preferably calcium chloride, and when the hydrogel precursor is kappa-carrageenan, the salt that provides cations in solution is preferably potassium chloride.

[0042] When the solution containing the inclusion 1 contains a salt that provides cations in the solution, the concentration of the salt that provides cations in the solution can be appropriately adjusted according to the type of the salt that provides cations in the solution used. For example, based on the total amount of the solution containing the inclusion 1, it may be 0.5% by mass or more, 1.5% by mass or more, or 3% by mass or more, and may be 20% by mass or less, 10% by mass or less, or 5% by mass or less.

[0043] The solution containing the inclusion 1 may contain lambda-carrageenan as other components. When the solution containing the inclusion 1 contains lambda-carrageenan, the concentration of lambda-carrageenan may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and may be 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total amount of the solution containing the inclusion 1.

[0044] In the gel layer coating step of the present embodiment, a solution containing the inclusion 1 and a substance (for example, a cation) that gels the hydrogel precursor as needed is added to the solution containing the hydrogel precursor, dropped, etc., so that the liquid containing the inclusion 1 and optionally the cation is brought into contact with the solution containing the hydrogel precursor. Then, by gelling the hydrogel precursor on the contacted surface, the inclusion 1 is coated with the gel layer 3 containing the hydrogel. Thereby, particles in which the inclusion 1 is coated with the gel layer 3 (hereinafter, also referred to as "gel layer-coated particles") are obtained.

[0045] When the solution containing the inclusion 1 contains a cation, gelling the hydrogel precursor is performed by bringing the solution containing the inclusion 1 into contact with the solution containing the hydrogel precursor. At this time, the time for contacting the solutions with each other (gelation time) may be 30 seconds or more, 45 seconds or more, or 1 minute or more, and may be 30 minutes or less, 20 minutes or less, or 十分钟 or less. At this time, the mixture may be allowed to stand, or the mixture may be stirred. At this time, the thickness of the coating of the gel layer 3 can be adjusted by adjusting the cation concentration of the solution containing the cation, the concentration of the hydrogel precursor, and the contact time.

[0046] Gelation of the hydrogel precursor may, depending on the type of the hydrogel precursor, be achieved by contacting a solution containing the inclusion 1 with a solution containing the hydrogel precursor and then cooling to gelate the hydrogel precursor.

[0047] In another embodiment, the gel layer coating step includes coating the inclusion 1 with a gel layer 3 containing a hydrogel by gelating the hydrogel precursor by contacting a solution containing both the liquid inclusion 1 and the hydrogel precursor with a solution containing a substance (e.g., a cation) that gelates the hydrogel precursor.

[0048] In this case, first, a solution containing both the liquid inclusion 1 and the hydrogel precursor and a solution containing a salt that provides a substance (e.g., a cation) that gelates the hydrogel precursor are prepared respectively. Specific embodiments of the inclusion 1, the hydrogel precursor, and the gelling substance are as described above.

[0049] Subsequently, the solution containing both the inclusion 1 and the hydrogel precursor is brought into contact with the solution containing a substance (e.g., a cation) that gelates the hydrogel precursor by adding, dropping, etc. the solution containing both the inclusion 1 and the hydrogel precursor to the solution containing a substance (e.g., a cation) that gelates the hydrogel precursor. Then, by gelating the hydrogel precursor on the contacted surface, the inclusion 1 is coated with the gel layer 3 containing the hydrogel. Thereby, gel layer-coated particles in which the inclusion 1 is coated with the gel layer 3 are obtained. Also at this time, the thickness of the coating of the gel layer 3 can be adjusted by adjusting the cation concentration of the solution containing the cation, the concentration of the hydrogel precursor, and the contact time.

[0050] The gel layer coating process described above preferably includes positively or negatively charging the gel layer 3. By positively or negatively charging the gel layer 3, the oil composition 4 can be effectively attached to the gel layer 3 by utilizing interionic interactions in the oil adhesion process described later. Positively or negatively charging the gel layer 3 can be achieved by adding a component having a positive or negative charge to the solution containing the encapsulation 1 and / or the hydrogel precursor, by using a hydrogel precursor having a positive or negative charge, or by adjusting the amount of hydrogel precursor added.

[0051] Components having a positive or negative charge include, for example, lambda-carrageenan. When the solution containing encapsulation 1 and / or the solution containing the hydrogel precursor contains lambda-carrageenan, the gel layer 3 is negatively charged by the sulfate groups of lambda-carrageenan. Hydrogel precursors having a positive or negative charge include, for example, kappa-carrageenan or iota-carrageenan. In this case, the gel layer 3 is negatively charged by the sulfate groups of each carrageenan. Adjusting the amount of hydrogel precursor added is, for example, when an excess of the hydrogel precursor such as alginic acid is added relative to the amount of cations in the solution containing encapsulation 1, the gel layer 3 is negatively charged by carboxyl groups that did not react with the cations.

[0052] In the oil and fat application process, first, an oil and fat emulsion is prepared. The oil and fat emulsion may be a commercially available product, or it may be prepared by mixing oil and fat, an emulsifier, and water, and then homogenizing the mixture. Preferably, the oil and fat emulsion is an oil-in-water emulsion. Specific examples of usable oils and fats and emulsifiers are as described above.

[0053] From the viewpoint of facilitating the adhesion of the oil and fat composition 4 to the gel layer 3, the oil and fat emulsion preferably has a positive or negative charge, and more preferably has a charge opposite to that of the gel layer 3. An oil and fat emulsion having a positive or negative charge can be obtained by preparing an emulsion using an emulsifier, as described above, that can impart a positive or negative charge.

[0054] The oil and fat content in the emulsion is preferably 0.05% by mass or more, more preferably 1% by mass or more, preferably 30% by mass or less, and more preferably 10% by mass or less, based on the total amount of the emulsion. The emulsifier content in the emulsion is preferably 0.01% by mass or more, more preferably 0.5% by mass or more, preferably 20% by mass or less, and more preferably 5% by mass or less, based on the total amount of the emulsion.

[0055] From the viewpoint of facilitating adhesion of the oil composition to the gel layer 3, the average particle size of the emulsified particles in the emulsion is preferably 10 μm or less, 1 μm or less, 800 nm or less, 500 nm or less, or 300 nm or less. The average particle size of the emulsified particles may also be 20 nm or more, 50 nm or more, or 100 nm or more. The oil emulsion is more preferably a so-called nanoemulsion in which the average particle size of the emulsified particles is less than 1 μm. The average particle size of the emulsified particles refers to D50 measured by a particle size distribution analyzer using laser diffraction / scattering.

[0056] Next, the gel-coated particles obtained by the gel-coating process are added to the oil emulsion, thereby bringing the oil emulsion into contact with the gel layer 3 in the gel-coated particles. As a result, a coating layer 2 is formed on the particles 10, with the oil composition 4 adhering to the gel layer 3. The oil composition 4 includes both the oil emulsion itself and the oil film formed when the emulsion particles in the emulsion coalesce as a result of the oil emulsion adhering to the gel layer.

[0057] The time for which the oil emulsion is in contact with the gel layer 3 is not particularly limited, but may be, for example, 10 seconds or more, 1 minute or more, or 5 minutes or more, and may be 1 hour or less, 30 minutes or less, or 15 minutes or less. From the viewpoint of ensuring sufficient coating with the oil composition 4, the oil emulsion may be in contact with the gel layer 3 for 1 hour or more. When bringing the oil emulsion into contact with the gel layer 3, the gel layer coating particles may be added to the oil emulsion and left to stand, or stirred.

[0058] In the manufacturing method according to this embodiment, a step may be provided between the gel layer coating step and the oil and grease adhesion step in which the gel layer coated particles are washed with water such as deionized water, or a solution containing the encapsulated substance 1. This makes it possible to wash away any excess components or ions adhering to the gel layer coated particles.

[0059] <Second Embodiment> Figure 2 is a schematic cross-sectional view showing particles according to the second embodiment. The particles 20 shown in Figure 2 comprise a liquid encapsulant 1 and a coating layer 2 that covers the encapsulant, and further comprises an inner layer 5 containing hydrogel between the encapsulant 1 and the coating layer 2. The coating layer 2 comprises a gel layer 3 containing hydrogel and an oil and fat composition 4 that adheres to the gel layer 3. The specific embodiments of the liquid encapsulant 1 and the coating layer 2 are the same as those in the first embodiment described above, so their description is omitted.

[0060] In the particles according to the second embodiment, the provision of an inner layer 5 further suppresses the leakage of the inclusions 1 to the outside of the particles.

[0061] The inner layer 5 contains at least a hydrogel. The hydrogel contained in the inner layer 5 may be the same as or different from the hydrogel contained in the gel layer 3. The type of hydrogel contained in the inner layer 5 can be selected to be the same as the hydrogel used in the gel layer 3 described above. The hydrogel contained in the inner layer 5 is preferably a polysaccharide gel, and more preferably an alginate gel.

[0062] The thickness (film thickness) of the inner layer 5 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more, from the viewpoint of maintaining the structure of the particles 20, and from the viewpoint of facilitating the release of the encapsulated material 1, it is preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.6 mm or less.

[0063] The inner layer 5 may be formed solely from hydrogel, or it may contain other components besides hydrogel. Examples of other components include lambda-carrageenan.

[0064] Next, a method for producing particles according to the second embodiment will be described. The method for producing particles 20 according to this embodiment comprises an inner layer coating step of coating a liquid encapsulant 1 with an inner layer 5 containing a first hydrogel, a gel layer coating step of coating the inner layer 5 with a gel layer 3 containing a second hydrogel, and an oil and fat attachment step of bringing an oil and fat emulsion into contact with the gel layer 3.

[0065] In one embodiment, the inner layer coating step includes contacting a liquid encapsulant 1 and, if necessary, a substance that gels the first hydrogel precursor (e.g., a cation) with a solution containing the first hydrogel precursor to gel the first hydrogel precursor, thereby coating the encapsulant 1 with an inner layer 5 containing the first hydrogel.

[0066] In this case, first, a solution containing the first hydrogel precursor and a solution containing encapsulation 1 and, if necessary, a substance that gels the first hydrogel precursor are prepared. The solution containing the first hydrogel precursor contains the first hydrogel precursor, water, and, if necessary, other components. The details of the substance that gels the hydrogel precursor are the same as described above.

[0067] Examples of the first hydrogel precursor include alginic acid or its salts, polysaccharides such as carrageenan and agar, pre-gelling gelatin, and proteins such as collagen. The first hydrogel precursor is preferably a polysaccharide, and more preferably alginic acid or its salts. Specific examples of alginic acid salts are as described above.

[0068] The concentration of the hydrogel precursor in the solution containing the first hydrogel precursor may be 0.1% by mass or more, 0.5% by mass or more, or 0.8% by mass or more, and may be 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total amount of the solution containing the first hydrogel precursor.

[0069] The solution containing the encapsulated substance 1 may be the same as the solution containing the encapsulated substance 1 described in the method for producing the particles 10 according to the first embodiment described above.

[0070] In the inner layer coating step of this embodiment, the encapsulated material 1 is brought into contact with the solution containing the hydrogel precursor by adding or dropping the solution containing the first hydrogel precursor. The encapsulated material 1 is then coated with an inner layer 5 containing the first hydrogel by gelling the first hydrogel precursor on the surface that has come into contact with the encapsulated material 1. As a result, particles in which the encapsulated material 1 is coated with the inner layer 5 (hereinafter also referred to as "inner layer coated particles") are obtained.

[0071] The first hydrogel precursor can be gelled by bringing the solution containing the encapsulation 1 into contact with the solution containing the first hydrogel precursor, provided that the solution containing the encapsulation 1 contains a substance that gels the first hydrogel. The time the solutions are in contact (gelling time) may be 30 seconds or more, 45 seconds or more, or 1 minute or more, and may be 10 minutes or less, 5 minutes or less, or 3 minutes or less. When bringing the solutions into contact, the mixture may be left to stand or the mixture may be stirred.

[0072] Depending on the type of first hydrogel precursor, the first hydrogel precursor may be gelled by bringing the solution containing the encapsulation 1 into contact with the solution containing the first hydrogel precursor and then cooling it.

[0073] In another embodiment, the inner layer coating step includes coating the encapsulation 1 with an inner layer 5 containing the first hydrogel by bringing a solution containing both the liquid encapsulation 1 and the first hydrogel precursor into contact with a solution containing a substance that gels the first hydrogel, thereby gelling the first hydrogel precursor.

[0074] In this case, first, a solution containing both the liquid encapsulation 1 and the first hydrogel precursor is prepared, and a solution containing a salt that provides cations in the solution is prepared separately.

[0075] Next, the solution containing both the encapsulation 1 and the first hydrogel precursor is brought into contact with the solution containing the gelling substance by adding it to the solution containing the gelling substance, such as by dropping it into the solution. The first hydrogel precursor is then gelled on the surface of the dropped solution, thereby coating the encapsulation 1 with the inner layer 5 containing the first hydrogel. This results in inner-layer coated particles in which the encapsulation 1 is coated with the inner layer 5.

[0076] The gel layer coating step preferably includes contacting the inner layer 5 of the inner layer coating particles with a solution containing a second hydrogel precursor to gel the second hydrogel precursor, thereby coating the inner layer 5 with a gel layer 3 containing the second hydrogel.

[0077] In this case, first, a solution containing the second hydrogel precursor is prepared. The solution containing the second hydrogel precursor contains the second hydrogel precursor, water, and other components as needed.

[0078] As the second hydrogel precursor, the same substance used in the gel layer coating step in the first embodiment described above can be used. The second hydrogel precursor may be the same substance as the first hydrogel precursor, or it may be a different substance. The second hydrogel precursor is preferably a polysaccharide, and more preferably alginic acid or a salt thereof.

[0079] In the solution containing the second hydrogel precursor, the concentration of the second hydrogel precursor may be 0.1% by mass or more, 0.5% by mass or more, or 0.8% by mass or more, and may be 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total amount of the solution containing the hydrogel precursor.

[0080] The solution containing the second hydrogel precursor may also contain lambda-carrageenan as another component. If the solution containing the second hydrogel precursor contains lambda-carrageenan, the concentration of lambda-carrageenan may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and 10% by mass or less, 5% by mass or less, or 3% by mass or less, based on the total amount of the solution containing the second hydrogel precursor.

[0081] Next, the inner layer 5 of the inner layer coating particle is brought into contact with a solution containing the second hydrogel precursor, and the second hydrogel precursor is gelled, thereby coating the inner layer 5 with a gel layer 3 containing the second hydrogel.

[0082] This step may include attaching a second hydrogel precursor to the inner layer 5, and then gelling the second hydrogel precursor. That is, one example of this step is to first add the inner layer coated particles obtained by the inner layer coating step to a solution containing the second hydrogel precursor, thereby bringing the inner layer 5 of the inner layer coated particles into contact with the solution containing the second hydrogel precursor. As a result, the second hydrogel precursor and any other components included as needed attach to the inner layer 5.

[0083] The time for contacting the inner layer 5 with the solution containing the second hydrogel precursor may be 10 seconds or more, 1 minute or more, or 5 minutes or more, and may be 1 hour or less, 30 minutes or less, or 15 minutes or less. From the viewpoint of ensuring sufficient coating by the gel layer 3, the inner layer 5 may be contacted with the solution containing the second hydrogel precursor for 1 hour or more. At this time, the mixture may be left to stand or the mixture may be stirred.

[0084] Subsequently, by gelling the second hydrogel precursor, particles (gel-coated particles) can be obtained in which the inner layer 5 of the inner-layer coated particles is coated with a gel layer 3 containing the second hydrogel.

[0085] Gelating the second hydrogel precursor preferably involves contacting the inner layer coated particles, to which the second hydrogel precursor and optionally other components are attached, with a solution containing a substance for gelling the second hydrogel precursor. The substance for gelling the second hydrogel precursor may, for example, be a cation for gelling the second hydrogel precursor, and may be a salt that provides cations in the solution described in the method for producing the particles 10 according to the first embodiment described above. This allows the second hydrogel precursor to gel, and the inner layer 5 of the inner layer coated particles to be coated with the gel layer 3.

[0086] The concentration of the cation-providing salt in a cation-containing solution can be appropriately adjusted depending on the type of cation-providing salt used. For example, based on the total amount of the solution containing the metal cation-providing salt, the concentration may be 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, and may be 10% by mass or less, 5% by mass or less, or 3% by mass or less.

[0087] The time during which the inner-layer coated particles are in contact with the cation-containing solution (gelling time) may be 30 seconds or more, 45 seconds or more, or 1 minute or more, and may be 30 minutes or less, 20 minutes or less, or 10 minutes or less. During this time, the mixture may be left to stand or the mixture may be stirred.

[0088] Depending on the type of second hydrogel precursor, the second hydrogel precursor may be gelled by first attaching it to the inner layer 5 using the method described above, and then cooling it.

[0089] The gel layer coating step preferably includes positively or negatively charging the gel layer 3. The method for positively or negatively charging the gel layer 3 may be the same as the method described in the first embodiment.

[0090] In the oil and fat attachment step, an oil and fat emulsion is prepared, and the gel-coated particles obtained in the gel-coating step are added to the oil and fat emulsion, thereby bringing the oil and fat emulsion into contact with the gel layer 3 on the gel-coated particles. As a result, the oil and fat composition 4 adheres to the gel layer 3, and a coating layer 2 is formed on the particles 20. The specific method of the oil and fat attachment step may be the same as the method described in the first embodiment.

[0091] In the manufacturing method according to this embodiment, a step may be provided between the inner layer coating step and the gel layer coating step, and / or between the gel layer coating step and the oil and grease adhesion step, in which the inner layer coated particles or gel layer coated particles are washed with water such as deionized water, or a solution containing the encapsulated substance 1. This makes it possible to wash away any excess components or ions attached to each particle.

[0092] <Third Embodiment> Figure 3 is a schematic cross-sectional view showing particles according to the third embodiment. The particles 30 shown in Figure 3 comprise a liquid encapsulant 1 and a coating layer 2 that covers the encapsulant, and further comprises an outer layer 6 that covers the coating layer 2. The coating layer 2 comprises a gel layer 3 containing a hydrogel and an oil and fat composition 4 that adheres to the gel layer 3. The specific embodiments of the liquid encapsulant 1 and the coating layer 2 are the same as those in the first embodiment described above, so their description is omitted. Although the particles 30 shown in Figure 3 have a flattened spherical shape, they may also be spherical or substantially spherical as shown in Figures 1 and 2.

[0093] In the particle according to the third embodiment, the provision of an outer layer 6 further suppresses the leakage of the inclusions 1 to the outside of the particle.

[0094] The outer layer 6 contains at least a hydrogel. The hydrogel contained in the outer layer 6 may be the same as or different from the hydrogel contained in the gel layer 3. The type of hydrogel contained in the outer layer 6 can be selected to be the same as the hydrogel used in the gel layer 3 described above. The hydrogel contained in the outer layer 6 is preferably a polysaccharide gel, and more preferably an alginate gel.

[0095] The thickness (film thickness) of the outer layer 6 is preferably 0.1 mm or more, more preferably 0.3 mm or more, and even more preferably 0.5 mm or more, from the viewpoint of maintaining the structure of the particles 30, and from the viewpoint of facilitating the release of the encapsulated material 1, it is preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.6 mm or less.

[0096] The outer layer 6 may be formed solely from hydrogel, or it may contain other components besides hydrogel. Examples of other components include lambda-carrageenan.

[0097] Next, a method for producing particles according to the third embodiment will be described. The method for producing particles 30 according to this embodiment comprises the steps of: stacking at least an oil emulsion, a solution containing a hydrogel precursor, and an inclusion in this order on a support sheet containing a hydrogel, gelling the hydrogel precursor to form a coating layer including a gel layer to which the oil composition is attached (hereinafter also referred to as "step X"); and forming particles using a laminate in which the support sheet, coating layer, and inclusion layers are stacked (hereinafter also referred to as "step Y").

[0098] In step X, first, a support sheet containing hydrogel is prepared. The support sheet is a sheet that constitutes the outer layer 6. The hydrogel in the support sheet may be the same as or different from the hydrogel contained in the gel layer 3 described above. The type of hydrogel contained in the support sheet can be selected to be the same as the hydrogel used in the gel layer 3 described above. The hydrogel contained in the support sheet is preferably a polysaccharide gel, and more preferably an alginate gel. From the viewpoint of preventing excessive interaction with other materials, it is preferable that the hydrogel in the support sheet is an uncharged gel.

[0099] The support sheet may be formed solely from hydrogel, or it may contain other components besides hydrogel.

[0100] The thickness of the support sheet is preferably 0.1 mm or more, more preferably 0.3 mm or more, even more preferably 0.5 mm or more, and also preferably 1 mm or less, more preferably 0.8 mm or less, and even more preferably 0.6 mm or less.

[0101] Next, at least an oil emulsion, a solution containing a hydrogel precursor, and the encapsulation 1 are layered on the support sheet in this order. This step may include layering other components between the oil emulsion, the hydrogel precursor, and the encapsulation.

[0102] The details of the fat and oil emulsion may be the same as those of the emulsion used in the manufacturing method of the first embodiment described above. The fat and oil emulsion preferably has a positive or negative charge, and more preferably has a charge opposite to that of the gel formed from the hydrogel precursor. For example, if the hydrogel precursor is alginic acid or a salt thereof, since alginic acid or a salt thereof has a negative charge, it is preferable that the fat and oil emulsion has a positive charge.

[0103] The oil emulsion may be distributed across the entire surface of the support sheet, or it may be distributed across a portion of the surface of the support sheet. The oil emulsion may be distributed in multiple locations on the support sheet, such as in dots or circles, in each of the multiple compartments on the support sheet. In this case, the solution containing the hydrogel precursor and the encapsulation 1, described later, are laminated on each of the multiple oil emulsions.

[0104] Next, a solution containing a hydrogel precursor is layered onto the area where the oil emulsion is placed. The details of the solution containing the hydrogel precursor may be the same as the solution used in the manufacturing method of the first embodiment described above, and the hydrogel precursor can be the same as the one used in the gel layer coating step in the first embodiment described above. The hydrogel precursor is preferably a polysaccharide, and more preferably alginic acid or a salt thereof.

[0105] Next, the encapsulated material 1 is further layered on the area where the solution containing the hydrogel precursor is placed. In this manufacturing method, the encapsulated material 1 contains a substance for gelling the hydrogel precursor. This allows the hydrogel precursor to gel when the encapsulated material is layered on the solution containing the hydrogel precursor. The substance for gelling the hydrogel precursor may be the same as the substance used in the manufacturing method of the first embodiment described above, for example, a cation-providing salt as described above.

[0106] By gelling the hydrogel precursor, a gel layer 3 is formed, and the oil and fat composition 4 derived from the oil and fat emulsion adheres to the gel layer 3, forming a coating layer 2.

[0107] In step X, the lamination of the oil emulsion, the solution containing the hydrogel precursor, and the encapsulation 1 can be carried out by coating or printing these liquids. Known methods can be used as appropriate for coating and printing. From the viewpoint of improving manufacturing efficiency, these laminations are preferably carried out by printing such as gravure printing, flexographic printing, screen printing, or inkjet printing. The lamination of the oil emulsion, the solution containing the hydrogel precursor, and the encapsulation 1 can also be carried out continuously using known printing means.

[0108] In step Y, the laminate prepared in step X, which consists of a support sheet, a coating layer 2 (a gel layer 3 to which the oil composition 4 is attached), and a layer of the encapsulated material 1, is used to form the material into particles. The forming into particles is preferably carried out, for example, by preparing two of the laminates and pressing them together so that the layers of the encapsulated material 1 overlap. Alternatively, it may be carried out by folding one laminate and wrapping it so that the layers of the encapsulated material 1 are not exposed.

[0109] In a method for pressing together two laminates, if an oil emulsion is placed in multiple compartments on a support sheet, and a layer of a hydrogel precursor solution and an encapsulation 1 are placed on each of the layers of oil emulsion, two such laminates may be prepared, and the two laminates may be pressed together so that the layers of encapsulation 1 overlap, and then cut into sections where the coating layer 2 and encapsulation 1 are placed. This method is preferable because multiple particles can be molded at once.

[0110] By going through process Y, particles 30 can be manufactured in which the encapsulated material 1 is covered with an outer layer 6 made of a support sheet and a coating layer 2. In particular, when two laminates are pressed together in process Y to form particles, the particles 30 may take on an oblate spherical shape (or other shapes such as lens-shaped or dorayaki-shaped), as shown in Figure 3.

[0111] Furthermore, in this manufacturing method, it is also possible to produce particles according to the first embodiment (particles without an outer layer 6) by further carrying out a step of removing the support sheet after step Y.

[0112] In the manufacturing method according to this embodiment, it is possible to continuously laminate multiple layers or to form layers corresponding to a large number of particles on two sheets and then compress and mold them all at once. Therefore, it is a suitable manufacturing method because it can speed up particle production and produce a large quantity of particles in a short time.

[0113] The average particle diameter of the particles in the embodiments described above (first, second, and third embodiments) may be 0.1 mm or more, 0.5 mm or more, or 1 mm or more, and may be 15 mm or less, 8 mm or less, or 5 mm or less. In this specification, the average particle diameter of the particles refers to D50 measured by a particle size distribution analyzer using laser diffraction / scattering.

[0114] The breaking strength of the particles according to the above embodiment is preferably 10 kPa or less, 8 kPa or less, 5 kPa or less, or 3 kPa or less. This makes it easier to release the encapsulated substance 1 within the particle. For example, if the particles according to this embodiment are a food composition or feed composition and the encapsulated substance 1 is a flavor component, then if the breaking strength is within this range, the particles can be easily broken by chewing, and the encapsulated substance 1 can be easily released into the oral cavity. On the other hand, from the viewpoint of making it easier to suppress the leakage of the encapsulated substance 1 out of the particle, the breaking strength of the particle is preferably 0.1 kPa or more, more preferably 0.5 kPa or more. In this specification, the breaking strength is a value measured by dividing the force at which the particle breaks by the cross-sectional area of ​​the particle when the particle is compressed at a compression speed of 60 mm / min using a viscoelasticity measuring device (rheometer) (for example, RTC-2002D-D, Rheotec Co., Ltd.).

[0115] The particles according to the above embodiment can be used as pharmaceuticals, quasi-drugs, food compositions, feed compositions, or additives thereof. The feed composition may be a feed composition for aquatic organisms.

[0116] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples. In the following examples, unless otherwise specified, "%" representing concentration means mass percent.

[0117] <Preparation of Particles> [Example 1] An aqueous solution containing sucrose (20% concentration), calcium chloride (2% concentration), and lambda-carrageenan (1.5% concentration) was prepared. This was added dropwise to an aqueous solution of alginate (1% concentration) as the first hydrogel precursor and allowed to stand for 1 minute. As a result, the alginate and calcium reacted and gelled, yielding particles (inner-layer coated particles) in which the sucrose solution as an encapsulant was coated with calcium alginate (containing lambda-carrageenan) as the inner layer. The obtained inner-layer coated particles were washed with deionized water.

[0118] The prepared inner-layer coated particles were added to a second hydrogel precursor solution containing alginic acid (1.5%) and lambda-carrageenan (1.5%), and allowed to stand for 2 minutes. This allowed alginic acid and lambda-carrageenan to adhere to the inner surface of the inner-layer coated particles. After washing the particles with water, these particles were added to a solution containing sucrose (20%) and calcium chloride (2%) and allowed to stand for 5 minutes. This caused the alginic acid and calcium to react and gel, resulting in inner-layer coated particles coated with calcium alginate as a gel layer (gel-coated particles). Subsequently, the gel-coated particles were washed with sucrose solution (20%) to remove excess calcium ions.

[0119] On the other hand, an emulsion of oil and fat was prepared by the following method. In this case, the chitosan-oleic acid complex disclosed in Non-Patent Document 1 was used as the emulsifier. 0.01 g of the chitosan-oleic acid complex was added to 0.5 g of soybean oil (Fujifilm Wako Pure Chemical Industries, Ltd.), and the mixture was treated with a high-pressure homogenizer (microfluidizer (LV1, Microfluidics)) to prepare a soybean oil emulsion. The particle size of the emulsified particles in the emulsion was 526 nm. At this time, the interface of the emulsified particles in the emulsion was positively charged due to the amino groups of the chitosan contained in the chitosan-oleic acid complex.

[0120] The prepared gel-coated particles were added to the emulsion solution described above and mixed for 10 minutes while stirring. This caused the emulsion to adhere to the gel-coated particles. The particles were then collected and washed with deionized water to obtain particles coated with a coating layer containing a gel layer with hydrogel (calcium alginate) and an oil and fat composition (emulsified oil and fat particles and their combination) adhering to the gel layer (Example 1).

[0121] [Comparative Example 1] Particles according to Comparative Example 1 were prepared in the same manner as in Example 1, except that a soybean oil emulsion was not attached to the gel layer of the gel-coated particles.

[0122] <Microscopic Observation of Particles> The particles of Example 1 were observed using an optical microscope (BZ9000, Keyence Corporation). The observation results are shown in Figure 4. As shown in Figure 4, it was confirmed that in the particle 20 of Example 1, the encapsulation 1 containing the sucrose solution was covered by the inner layer 5 and the coating layer 2. Furthermore, when an oil-soluble fluorescent dye was added to soybean oil and fluorescence observation was performed, it was confirmed that the oil and fat composition was attached to the entire surface of the particles of Example 1. This is thought to be because the lambda carrageenan added to the gel layer made the gel layer negatively charged, and then, when the positively charged oil and fat emulsion was brought into contact with it, the oil and fat composition adhered to the gel layer due to interionic interactions.

[0123] <Confirmation of Leakage of Inclusions> Until the start of the test, the particles of Example 1 and Comparative Example 1 were stored in a 20% sucrose solution. Then, the particles of Example 1 and Comparative Example 1 were washed three times with deionized water, and 1 g of each particle was immersed in 5 g of deionized water. During immersion, the sucrose concentration (%) of the water in which the particles were immersed was measured at predetermined intervals using a sugar meter (handheld refractometer (SK-104R, Sato Keiryoki Mfg. Co., Ltd.)). Figure 5 shows the change in sucrose concentration over time. As shown in Figure 5, when the particles of Example 1, which had the oil composition attached, were immersed, the sucrose concentration of the water immediately after immersion was lower than when the particles of Comparative Example 1, which did not have the oil composition, were immersed, and the sucrose concentration during immersion was also consistently lower. After 80 minutes from the start of immersion, the sucrose concentration of the water was 2.6% when the particles of Example 1 were immersed, and 3.0% when the particles of Comparative Example 1 were immersed. In other words, it was found that the leakage of encapsulated material from the particles was suppressed more effectively in the particles of Example 1 than in the particles of Comparative Example 1.

[0124] <Particle Breaking Strength> The breaking strength of the particles in Example 1 was measured by dividing the force at which the particles broke by the cross-sectional area of ​​the particles when the particles were compressed at a compression speed of 60 mm / min using a viscoelasticity measuring device (FUDOH rheometer (RTC-2002D-D, Rheotec Co., Ltd.)). For comparison, the breaking strength of fish eggs (ikura) was also measured under similar conditions. Figure 6 shows the measurement of the breaking strength. The breaking strength of the particles in Example 1 was 2.69 kPa, and the breaking strength of the fish eggs was 5.13 kPa. Since the breaking strength of the particles in Example 1 is as low as that of fish eggs, it is thought that when releasing the inclusions from the particles, the inclusions can be released from the particles with a smaller impact or pressure.

[0125] 1...Inclusions, 2...Coating layer, 3...Gel layer, 4...Oil composition, 5...Inner layer, 6...Outer layer, 10, 20, 30...Particles.

Claims

1. A particle comprising a liquid encapsulant and a coating layer covering the encapsulant, wherein the coating layer comprises a gel layer containing a hydrogel and an oily composition adhering to the gel layer.

2. The particle according to claim 1, wherein the hydrogel comprises a gel derived from a polysaccharide.

3. The particle according to claim 2, wherein the polysaccharide-derived gel comprises an alginate gel.

4. The particles according to any one of claims 1 to 3, wherein the oil and fat composition contains oil and fat and an emulsifier.

5. The particle according to any one of claims 1 to 3, wherein the gel layer further comprises lambda carrageenan.

6. The particle according to any one of claims 1 to 3, further comprising an inner layer containing a hydrogel between the encapsulated substance and the coating layer.

7. The particle according to claim 6, wherein the hydrogel contained in the inner layer includes an alginate gel.

8. The particle according to any one of claims 1 to 3, further comprising an outer layer containing a hydrogel that covers the coating layer.

9. The particle according to any one of claims 1 to 3, wherein the breaking strength is 10 kPa or less.

10. Particles according to any one of claims 1 to 3, which are a food composition or a feed composition.

11. A method for producing particles comprising a liquid encapsulant and a coating layer covering the encapsulant, the method comprising: a gel layer coating step of covering the encapsulant with a gel layer containing a hydrogel; and an oil and fat adhesion step of contacting the gel layer with an emulsion of oil and fat.

12. A method for producing particles comprising a liquid encapsulant, a coating layer covering the encapsulant, and an inner layer provided between the encapsulant and the coating layer, the method comprising: an inner layer coating step of covering the encapsulant with the inner layer containing a first hydrogel; a gel layer coating step of covering the inner layer with a gel layer containing a second hydrogel; and an oil and fat adhesion step of contacting the gel layer with an oil and fat emulsion.

13. The manufacturing method according to claim 11 or 12, wherein the gel layer coating step includes positively or negatively charging the gel layer, and the oil and grease application step includes contacting the gel layer with an emulsion having a charge opposite to the charge of the gel layer.

14. A method for producing particles comprising a liquid encapsulant and a coating layer covering the encapsulant, comprising the steps of: laminating at least an emulsion of oil and fat, a solution containing a hydrogel precursor, and the encapsulant in this order on a support sheet containing a hydrogel, and gelling the hydrogel precursor to form a coating layer including a gel layer to which the oil and fat composition is attached; and forming the particles using a laminate formed by laminating the support sheet, the coating layer, and the encapsulant layer.

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