JP2024095759A - Retention agent for active ingredients - Google Patents

Abstract

The present invention provides a retention agent that can enhance and/or prolong the effects of active ingredients in the fields of medicine, cosmetics, food and beverages, etc.
[Solution] A retention agent used for retaining an active ingredient includes an oil-in-water emulsion containing water, a hydrophobic substance, cyclodextrin, and a thickening polysaccharide. Preferably, the hydrophobic substance is one or more selected from the group consisting of fats and oils, hydrophobic waxes, and hydrophobic resins, and the thickening polysaccharide is one or more selected from the group consisting of carboxymethylcellulose, xanthan gum, locust bean gum, guar gum, glucomannan, κ-carrageenan, ι-carrageenan, λ-carrageenan, tamarind gum, gellan gum, gum arabic, pectin, phosphate cross-linked starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, tragacanth gum, hydroxypropylcellulose, methylcellulose, hydroxypropylmethylcellulose, etc.
[Selection diagram] None

Description

The present invention relates to a retention agent used to retain an active ingredient, comprising an oil-in-water emulsion containing water, a hydrophobic substance, a cyclodextrin, and a thickening polysaccharide.

Today, emulsion compositions containing fats and oils, water, cyclodextrin, and water-soluble gelling agents are widely used in a variety of fields, including medicine, cosmetics, and food and beverages.

Patent Document 1 discloses an emulsion composition containing water, an oily component, α-cyclodextrin, and one or more of agar, low-strength agar, a combination of galactomannan or glucomannan with xanthan gum, carrageenan, furcellaran, gellan gum, and native gellan gum as gel-forming components, and also discloses pharmaceuticals, cosmetics, and chemical products that use the emulsion composition.

Patent Document 2 discloses an emulsion composition that contains fats and oils, hydrolyzed proteins, water, cyclodextrin, and the like, and also discloses that gums such as xanthan gum, guar gum, gum arabic CMC, carrageenan, and locust bean gum may be used as stabilizers.

Patent Document 3 discloses an emulsified cosmetic product obtained by mixing an aqueous raw material in which a water-soluble polymer compound such as pectin, gum tragacanth, gelatin, casein, sodium alginate, hydroxypropyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, sodium polyacrylate, or carboxyvinyl polymer is dissolved, with an oil-based raw material for cosmetics, and emulsifying the mixture by adding cyclodextrin.

Patent Document 4 discloses an emulsion composition for skin that contains water, fats and oils, cyclodextrin, and at least one water-soluble gelling agent selected from the group consisting of carboxymethylcellulose (CMC), xanthan gum, locust bean gum, guar gum, glucomannan, κ-carrageenan, ι-carrageenan, λ-carrageenan, tamarind gum, and gellan gum.

Non-Patent Document 1 describes that the emulsion stability was increased when xanthan gum and tragacanth gum were added as emulsion stabilizers to an oil-in-water emulsion made by emulsifying a sample of soybean oil and an aqueous cyclodextrin solution in a 1:1 volume ratio.

JP 2016-204311 A Japanese Patent Application Laid-Open No. 10-262560 Japanese Patent Publication No. 61-038166 WO2022/064997

Nippon Shokuhin Kogyo Gakkaishi, Vol. 38, No. 1, 16-20 (1991)

In the fields of medicine, cosmetics, food and beverages, etc., there has long been a desire to reduce the content of active ingredients such as drugs and taste components for reasons such as reducing the burden on patients and increasing health consciousness among consumers, and therefore there has been a demand for means that make it possible to enhance and/or prolong the effects of active ingredients. Therefore, the present invention aims to provide a new means that makes it possible to enhance and/or prolong the effects of active ingredients.

The inventors of the present invention have conducted extensive research to solve the above problems and have found that an oil-in-water emulsion containing a hydrophobic substance, water, cyclodextrin, and a thickening polysaccharide can adhere to animal tissue and retain the active ingredient there, and/or absorb, adsorb, and retain the active ingredient, thereby allowing it to remain there, thereby enhancing and/or prolonging the effect of the active ingredient in the tissue.

The present invention is based on these new findings and includes the following inventions.
[1] A retention agent used to retain an active ingredient, comprising an oil-in-water emulsion containing water, a hydrophobic substance, a cyclodextrin, and a thickening polysaccharide.
[2] The retention agent according to [1], wherein the hydrophobic substance is one or more selected from the group consisting of oils and fats, hydrophobic waxes, and hydrophobic resins.
[3] The retention agent according to [1] or [2], wherein the thickening polysaccharide is one or more selected from the group consisting of carboxymethylcellulose (CMC), xanthan gum, locust bean gum, guar gum, glucomannan, κ-carrageenan, ι-carrageenan, λ-carrageenan, tamarind gum, gellan gum, gum arabic, pectin, phosphate cross-linked starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, tragacanth gum, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl cellulose.
[4] A retention agent according to any one of [1] to [3], which is added to a food or drink.
[5] A retention agent according to any one of [1] to [3], which is added to a pharmaceutical.
[6] A retention agent according to any one of [1] to [3], which is added to a cosmetic product.
[7] A method for producing a retention agent used to retain an active ingredient, comprising the step of mixing water, a hydrophobic substance, a cyclodextrin, and a thickening polysaccharide to form an oil-in-water emulsion.
[8] A food or beverage comprising a retention agent used to retain an active ingredient, the retention agent comprising an oil-in-water emulsion containing water, a hydrophobic substance, cyclodextrin, and a thickening polysaccharide, in an amount of 0.5% by mass to 55% by mass in terms of the amount of the hydrophobic substance.
[9] A pharmaceutical comprising a retention agent used to retain an active ingredient, the retention agent comprising an oil-in-water emulsion containing water, a hydrophobic substance, cyclodextrin, and a thickening polysaccharide, in an amount of 0.5% by mass to 55% by mass in terms of the amount of the hydrophobic substance.
[10] A cosmetic comprising a retention agent used to retain an active ingredient, the retention agent comprising an oil-in-water emulsion containing water, a hydrophobic substance, cyclodextrin, and a thickening polysaccharide, in an amount of 0.5% by mass to 55% by mass in terms of the amount of the hydrophobic substance.
[11] Use of an oil-in-water emulsion containing water, a hydrophobic substance, a cyclodextrin, and a thickening polysaccharide in a method for producing a retention agent used for retaining an active ingredient.
This specification includes the contents described in the specification of Japanese Patent Application No. 2022-211335, filed on December 28, 2022, which is the priority basis of this application.
All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety.

The present invention provides an active ingredient retention agent that can retain an active ingredient on the tissues of an animal, thereby enhancing and/or prolonging the effects of the active ingredient.

FIG. 1 is a graph showing the results of evaluation of the change in taste intensity over one minute after ingestion of each sample prepared by mixing components of each taste quality with an aqueous solution of the oil-in-water emulsion according to the present invention (1% O/W(+)) and an aqueous solution (1% O/W(-)) of a mixture of components constituting an oil-in-water emulsion (not forming an oil-in-water emulsion), using the Time Intensity (TI) method using sensory evaluation software FIZZ (Biosystemes, Inc.) (sweetness: N=4, saltiness/bitterness: N=5, sourness/umami: N=3. Results are shown as average values). FIG. 2 is a graph showing the results of evaluation by the Time Intensity (TI) method using sensory evaluation software FIZZ (Biosystemes) of the change in taste intensity over one minute after ingesting a saline solution before (before application) and after (after application) application of an aqueous solution of the oil-in-water emulsion according to the present invention (10% O/W(+)) in the oral cavity (N=4).

1. Oil-in-water emulsion The oil-in-water emulsion of the present invention contains water, a hydrophobic substance, a cyclodextrin, and a thickening polysaccharide.

In the present invention, the "hydrophobic substance" refers to a substance that is insoluble in water and capable of forming an oil-in-water emulsion together with water and cyclodextrin and thickening polysaccharides, which will be described in detail below. Although there is no particular limitation, preferred examples include fats and oils, hydrophobic waxes, and hydrophobic resins. The hydrophobic substance may be any substance used alone, or different types of hydrophobic substances may be used in combination. For example, the hydrophobic substance may be one or more substances selected from the group consisting of fats and oils, hydrophobic waxes, and hydrophobic resins, and an appropriate substance may be selected and used depending on the usage mode of the retention agent of the present invention.

In the present invention, "oil-in-water emulsion" refers to an emulsion composition in which a hydrophobic substance is dispersed in water, and cyclodextrin and thickening polysaccharides contribute to the formation and stability of this emulsion.

In the present invention, the term "oils and fats" refers to oils and fats that are generally used in the formation of oil-in-water emulsions, and both polar and non-polar oils and fats can be used. Examples of such oils and fats include vegetable oils and fats (e.g., canola oil, rapeseed oil, soybean oil, corn oil, cottonseed oil, peanut oil, sesame oil, rice oil, rice bran oil, camellia oil, safflower oil, olive oil, linseed oil, perilla oil, perilla oil, sunflower oil, palm oil, tea oil, coconut oil, avocado oil, kukui nut oil, grapeseed oil, cocoa butter, coconut oil, wheat germ oil, almond oil, evening primrose oil, castor oil, hazelnut oil, macadamia nut oil, rosehip oil, grape oil, etc.). , cocoa oil, jojoba oil, palm kernel oil, etc.), isostearyl alcohol, capryl alcohol, lauryl alcohol, stearyl alcohol, 2-octadecyl alcohol, myristyl alcohol, cetyl alcohol, phytosterol, cholesterol, stearic acid, isostearic acid, capric acid, lanolinic acid, lauric acid, myristic acid, palmitic acid, behenic acid, linoleic acid, linolenic acid, glyceryl monostearate, glyceryl monopalmitate, mono Glyceryl behenate, glyceryl monomyristate, glyceryl monolaurate, glyceryl monolanolate, glyceryl monolinoleate, glyceryl monolinolenate, glyceryl monooleate, glyceryl triisostearate, isopropyl myristate, glycerol tri-2-heptylundecanoate, glycerol tri-2-ethylhexanoate, 2-heptylundecyl palmitate, di-2-heptylundecyl adipate, cetyl isooctadecyl Examples of the oils and fats used in the present invention include, but are not limited to, synthetic ester oils such as tallow, lard, lanolin, squalene, and squalane, silicone oils, and the like, but are not limited to these. The oils and fats used in the present invention are preferably those that are in a liquid state at least at room temperature, and are preferably oils and fats derived from animals or plants that are highly safe, and are particularly preferably edible vegetable oils that have been used in food and are highly safe. The oils and fats may be used alone or in combination with different oils and fats, and the appropriate one may be selected and used depending on the usage mode of the retention agent of the present invention. In this specification, "room temperature" means 5 to 35°C, preferably 15 to 30°C.

In the present invention, the term "hydrophobic wax" refers to natural hydrophobic wax derived from animals, plants, petroleum or minerals, and synthetic hydrophobic waxes. Waxes having a melting point of 80°C or less can be used, and those that are in a liquid state at least at room temperature are preferred. Examples of such hydrophobic waxes include beeswax, whale wax, wool wax, Japan wax, rosin (pine resin), candelilla wax, carnauba wax, cocoa butter, paraffin wax, microcrystalline wax, ceresin wax, petrolatum wax, ozokenit wax, polyethylene wax, oxidized polyethylene wax, Fischer-Tropsch wax, alcohol-modified wax, maleic acid-modified oxidized polyethylene wax, amide wax, and the like, but are not limited thereto. As the hydrophobic wax used in the present invention, highly safe hydrophobic waxes derived from animals or plants are particularly preferred. Any of the hydrophobic waxes may be used alone, or different hydrophobic waxes may be used in combination. Depending on the mode of use of the retention agent of the present invention, an appropriate wax may be selected and used.

In the present invention, the term "hydrophobic resin" refers to a resin that does not have hydrophilic groups or has a small content of hydrophilic groups and does not dissolve in polar solvents such as water. In the present invention, a resin that is in a liquid state at least at room temperature can be preferably used. Examples of such hydrophobic resins include silicone resins (not hydrophilized), polyurethane resins, fluorine-containing resins, polyethylene resins, polypropylene resins, polyester resins, acrylic resins, polystyrene resins, polycarbonate resins, polyvinyl chloride resins, polysulfone resins, polyethersulfone resins, polyaramid resins, polyamide resins, polyether resins, polyacrylonitrile resins, polyetherimide resins, and copolymers of these polymers, but are not limited to these. As the hydrophobic resin used in the present invention, a highly safe resin that has been confirmed to have biocompatibility and bioaffinity is particularly preferable. Any hydrophobic resin may be used alone, or different hydrophobic resins may be used in combination, and an appropriate one can be selected and used depending on the usage mode of the retention agent of the present invention.

In the present invention, the "hydrophobic substance" is preferably fats and oils and hydrophobic waxes, and is particularly preferably fats and oils.

The oil-in-water emulsion of the present invention may contain any amount of hydrophobic substance, for example, 1% by mass or more, 3% by mass or more, 5% by mass or more, or 7% by mass or more, and the upper limit is not particularly limited, but may be, for example, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less. The range of the amount of hydrophobic substance in the oil-in-water emulsion of the present invention may be expressed using two numerical values selected from the lower and upper numerical values, respectively, and for example, the oil-in-water emulsion of the present invention may contain the hydrophobic substance in an amount appropriately selected from the range of 1% by mass to 50% by mass, 1% by mass to 30% by mass, 1% by mass to 20% by mass, or 1% by mass to 10% by mass, preferably 5% by mass to 10% by mass, or 7% by mass to 10% by mass. If the amount of hydrophobic substance is less than 1% by mass, emulsification may be insufficient, while if the amount of hydrophobic substance is more than 50% by mass, the product may feel sticky or slimy. In either case, the active ingredient may not be retained in the intended form of use, or the desired feel may not be obtained.

In this specification, the amount of each component contained in the oil-in-water emulsion of the present invention is expressed in terms of mass %, with the total mass of the oil-in-water emulsion being 100 mass %.

In the oil-in-water emulsion of the present invention, water can be contained in any amount that can emulsify the hydrophobic substance and form an oil-in-water emulsion together with the cyclodextrin and thickening polysaccharide. For example, the oil-in-water emulsion of the present invention contains water in an amount of 15% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 45% by mass or more, 50% by mass or more, 60% by mass or more, or 70% by mass or more, and the upper limit is not particularly limited, but can be, for example, 90% by mass or less, or 85% by mass or less. The range of the amount of water in the oil-in-water emulsion of the present invention can be expressed using two numerical values selected from the lower and upper numerical values, respectively, and for example, the oil-in-water emulsion of the present invention can contain water in an amount appropriately selected from the range of 15% by mass to 90% by mass, 45% by mass to 90% by mass, or 70% by mass to 85% by mass. The amount of water contained in the oil-in-water emulsion of the present invention is preferably greater than the amount of the hydrophobic substance in terms of volume ratio, and for example, the content of the hydrophobic substance and water can be greater than 1:1 in terms of volume ratio (hydrophobic substance:water), for example, 1:2 or more, 1:3 or more, 1:4 or more, 1:5 or more, 1:6 or more, 1:10 or more, 1:15 or more, or 1:20 or more, and the upper limit of the amount of water is not particularly limited, but can be 1:90 or less, 1:80 or less, 1:70 or less, 1:60 or less, or 1:50 or less. By adjusting the amounts of water and hydrophobic substance contained in the oil-in-water emulsion of the present invention to the above ranges, stickiness, sliminess, etc. can be suppressed.

"Cyclodextrin" refers to a cyclic non-reducing maltooligosaccharide whose constituent unit is glucose, and examples of this include α-cyclodextrin, which has six glucose units, β-cyclodextrin, which has seven glucose units, and γ-cyclodextrin, which has eight glucose units. In the present invention, α-, β-, and γ-cyclodextrins, as well as derivatives thereof, and any combination thereof can be used. Examples of cyclodextrin derivatives include, but are not limited to, ethyl cyclodextrin, methyl cyclodextrin, hydroxyethyl cyclodextrin, hydroxypropyl cyclodextrin, methylamino cyclodextrin, amino cyclodextrin, carboxyethyl cyclodextrin, carboxymethyl cyclodextrin, sulfoxyethyl cyclodextrin, sulfoxyl cyclodextrin, acetyl cyclodextrin, branched cyclodextrin, cyclodextrin fatty acid ester, glucosyl cyclodextrin, and maltosyl cyclodextrin. α-cyclodextrin is preferably used. α-cyclodextrin is highly soluble in water, and can be used to obtain an oil-in-water emulsion with little roughness.

In the oil-in-water emulsion of the present invention, cyclodextrin can be included in an amount that contributes to the emulsification and stability of the oil-in-water emulsion together with the thickening polysaccharide, and that allows the desired feeling of use to be obtained in the form of use in the intended application. For example, the oil-in-water emulsion of the present invention contains cyclodextrin in an amount of 0.5% by mass or more, 1% by mass or more, 2.5% by mass or more, 3% by mass or more, 4% by mass or more, 4.5% by mass or more, or 5% by mass or more, and the upper limit is not particularly limited, but can be, for example, 15% by mass or less, 10% by mass or less, 9% by mass or less, 8% by mass or less, 7% by mass or less, or 6% by mass or less. The range of the amount of cyclodextrin in the oil-in-water emulsion of the present invention can be expressed using two numerical values selected from the above-mentioned lower and upper numerical values, respectively. For example, the oil-in-water emulsion of the present invention can contain cyclodextrin in an amount appropriately selected from the range of 0.5% by mass to 15% by mass, for example, 1% by mass to 15% by mass, 2.5% by mass to 10% by mass, 2.5% by mass to 9% by mass, 3% by mass to 9% by mass, 4% by mass to 8% by mass, 4.5% by mass to 9% by mass, or 5% by mass to 7% by mass, preferably 2.5% by mass to 9% by mass, or 4.5% by mass to 9% by mass. If the amount of cyclodextrin is less than 0.5% by mass, the emulsification and stability of the oil-in-water emulsion may be insufficient, while if it is more than 15% by mass, the viscosity of the oil-in-water emulsion may become too high or it may have a strong squeaky feeling. In either case, it may not be possible to retain the active ingredient in the intended application or to obtain the desired feel when used.

In the present invention, "thickening polysaccharides" generally means polysaccharides that dissolve in water and impart viscosity (sometimes also called thickening stabilizers, water-soluble thickeners, etc.). Thickening polysaccharides that can be used in the present invention include ingredients that are commonly used in the manufacture of foods and beverages, medicines (including quasi-drugs), cosmetics, etc., and are not particularly limited. Any thickening polysaccharide may be used alone, or different thickening polysaccharides may be used in combination, and an appropriate one may be selected and used depending on the usage mode of the retention agent of the present invention. In the present invention, the "thickening polysaccharide" preferably includes carboxymethylcellulose (CMC), xanthan gum, locust bean gum, guar gum, glucomannan, κ-carrageenan, ι-carrageenan, λ-carrageenan, tamarind gum, gellan gum, gum arabic, pectin, phosphate cross-linked starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, tragacanth gum, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, hydroxyethyl cellulose, etc. Any of these may be used alone, or two or more different types may be used in combination.

In the present invention, the "thickening polysaccharide" is more preferably carboxymethylcellulose (CMC), xanthan gum, locust bean gum, guar gum, glucomannan, κ-carrageenan, ι-carrageenan, λ-carrageenan, tamarind gum, and gellan gum, and even more preferably carboxymethylcellulose (CMC), glucomannan, tamarind gum, and xanthan gum. These thickening polysaccharides can particularly impart high emulsion stability to the oil-in-water emulsion of the present invention.

In the oil-in-water emulsion of the present invention, the thickening polysaccharide can be contained in an amount that contributes to the emulsification and stability of the oil-in-water emulsion together with cyclodextrin and that allows the desired feeling of use to be obtained in the form of use for the intended application. For example, the oil-in-water emulsion of the present invention contains the thickening polysaccharide in an amount of 0.05% by mass or more, 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more, and the upper limit is not particularly limited, but can be, for example, 1% by mass or less, 0.8% by mass or less, 0.7% by mass or less, 0.6% by mass or less, or 0.5% by mass or less. The range of the amount of thickening polysaccharide in the oil-in-water emulsion of the present invention can be expressed by using two numerical values selected from the above lower and upper numerical values, respectively. For example, the oil-in-water emulsion of the present invention can contain the thickening polysaccharide in an amount appropriately selected from the range of 0.05% by mass to 1% by mass, 0.1% by mass to 1% by mass, 0.2% by mass to 0.8% by mass, or 0.2% by mass to 0.5% by mass. If the amount of thickening polysaccharide is less than 0.05% by mass, the emulsification and stability of the oil-in-water emulsion may be insufficient, while if it is more than 1% by mass, the viscosity of the oil-in-water emulsion may be too high. In either case, the active ingredient may not be retained or the desired feeling of use may not be obtained in the form of use for the intended purpose.

In the oil-in-water emulsion of the present invention, the emulsification and stability of the oil-in-water emulsion are imparted by the combined use of the cyclodextrin and the thickening polysaccharide. The emulsification and stability of the oil-in-water emulsion brought about by the combined use of the cyclodextrin and the thickening polysaccharide do not depend on a three-dimensional matrix gel formed by dissolving a general gelling agent in water and cooling (preferably does not include a three-dimensional matrix gel), but is considered to be due to the presence of an interaction caused by hydrogen bonds generated between the cyclodextrin and the thickening polysaccharide, as described in detail in the following examples. In addition, since the oil-in-water emulsion of the present invention has emulsification and stability due to the combined use of the cyclodextrin and the thickening polysaccharide, it may be substantially free of emulsifiers commonly used in the production of conventional emulsion compositions, and preferably does not substantially contain the emulsifier. In the present invention, "substantially free of emulsifiers" means that the emulsifier is not included in the oil-in-water emulsion of the present invention in a form that exerts an emulsifying effect, and does not mean that no emulsifier is included at all. By being substantially free of emulsifiers, the present invention can obtain an advantageous oil-in-water emulsion that is highly safe, for example, less irritating and less allergenic, when the oil-in-water emulsion of the present invention is applied. Examples of "emulsifiers commonly used in the production of conventional emulsion compositions" include, but are not limited to, proteins, peptides or hydrolysates thereof, glycerin fatty acid esters, organic acid monoglycerides, polyglycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene fatty acid esters, polyglycerin condensed ricinoleic acid esters, sorbitan fatty acid esters, polyoxyethylene sorbit fatty acid esters, sucrose fatty acid esters, lecithin, enzymatically decomposed lecithin, polyethylene glycol, polypropylene glycol, etc.

The form of the oil-in-water emulsion of the present invention is not particularly limited, and in addition to the form having the above water content, it can be provided in the form of a semi-solid/semi-liquid (gel, sol, etc.) or a dried body (e.g., powder, flakes, etc.) prepared by reducing the water content. Such a semi-solid/semi-liquid (gel, sol, etc.) or dried body (e.g., powder, flakes, etc.) form can be obtained by obtaining an oil-in-water emulsion having the above water content, and then subjecting it to a conventionally known drying means to reduce the water content of the oil-in-water emulsion. Examples of such drying means include, but are not limited to, freeze drying, heat drying, air drying, spray drying, drum drying, hot air drying, vacuum drying, etc. The water content of the oil-in-water emulsion after being subjected to the drying means can be appropriately selected depending on the desired form. If it is in the form of a dried body, it can be, for example, less than 15% by mass, 10% by mass or less, 5% by mass or less, or 1% by mass or less. The lower limit of the water content of the oil-in-water emulsion after being subjected to the drying means is not particularly limited, but may be 0% by mass or more, more than 0% by mass, 0.1% by mass or more, 0.5% by mass or more, 0.6% by mass or more, 0.7% by mass or more, or 0.8% by mass or more. The range of the water content in the form of the dried product can be expressed using two numerical values selected from the upper and lower numerical values, respectively, and for example, the water content of the oil-in-water emulsion can be 0% by mass to less than 15% by mass, more than 0% by mass to less than 15% by mass, 0.1% by mass to less than 15% by mass, 0.1% by mass to 10% by mass, 0.5% by mass to 5% by mass, 0.5% by mass to 1% by mass, 0.6% by mass to 1% by mass, 0.7% by mass to 1% by mass, or 0.8% by mass to 1% by mass. The oil-in-water emulsion of the present invention after being subjected to the drying means does not undergo a phase transition to produce a water-in-oil emulsion, and in particular, the dried form has high heat resistance and moisture resistance, and does not discolor or dissolve even after being subjected to high temperature (e.g., about 100°C to 200°C) conditions and/or high humidity (e.g., about 95% humidity) conditions.

In addition to the above components, the oil-in-water emulsion of the present invention may further contain, as necessary, components (hereinafter referred to as "other components") that are normally used in the manufacture of intended uses such as food and beverages, medicines (including quasi-drugs), and cosmetics, in amounts appropriate to the desired use form, within a range that does not impair the effects of the present invention. Examples of such other components include, but are not limited to, excipients, disintegrants, lubricants, binders, diluents, buffers, suspending agents, thickeners, preservatives, antibacterial agents, preservatives, antioxidants, UV absorbers, colorants, pigments, dyes, pigments, lubricants, plasticizers, solvents, solubilizers, isotonicity agents, flavorings, vitamins, surfactants, pH adjusters, and chelating agents.

The oil-in-water emulsion of the present invention can be produced by mixing and stirring the water, hydrophobic substance, cyclodextrin, thickening polysaccharide, and other components as necessary in the amounts described above. All of the components may be mixed and stirred together, or the components may be added separately or in any combination in sequence (in any order) and mixed and stirred. The oil-in-water emulsion obtained by mixing and stirring may be subjected to heat sterilization.

The oil-in-water emulsion obtained by mixing and stirring may be subjected to drying means as required. The drying means may be any of the conventionally known drying means described above, and the water content of the oil-in-water emulsion may be appropriately adjusted depending on the desired shape of the semi-solid/semi-liquid (gel, sol, etc.) or dried body. The resulting dried body may be subjected to further crushing, pulverization, or grinding treatment as required to obtain a powder, flakes, or the like. The oil-in-water emulsion obtained by drying may be mixed and stirred with other components in the amounts described above as required, and/or may be subjected to heat sterilization treatment.

2. Uses The oil-in-water emulsion of the present invention can be used as a retention agent for retaining an active ingredient.

In the present invention, a "retention agent" is an agent that can retain or maintain an active ingredient at a specific site for a longer period of time, thereby enabling the effect of the active ingredient to be enhanced and/or maintained for a longer period of time compared to when the retention agent is not used. When the retention agent of the present invention is administered or ingested by an animal together with an active ingredient, the oil-in-water emulsion adheres to the tissue at the application site, where it can retain the active ingredient and/or absorb, adsorb and retain the active ingredient, thereby enabling the effect of the active ingredient to be enhanced and/or maintained for a longer period of time compared to when the retention agent is not used.

In the present invention, "animal" is not particularly limited and may be any animal, but is preferably a mammal, and examples thereof include (but are not limited to) humans, livestock animals (cattle, horses, sheep, pigs, goats, etc.), and pet animals (dogs, cats, rabbits, hamsters, guinea pigs, etc.), and more preferably humans.

In the present invention, "tissue" refers to various epithelial tissues found in the skin, oral cavity, esophagus, anus, vagina, nasal cavity, trachea, bronchi, stomach, small intestine, large intestine, fallopian tube, uterus, pleura, peritoneum, vascular endothelium, alveoli, thyroid gland (follicles), renal tubules, ureters, bladder, etc., as well as hair, nails, teeth, etc., and can be appropriately selected depending on the intended application site. In the present invention, "epithelial tissue" refers preferably to various epithelial tissues found in the skin, oral cavity, esophagus, nasal cavity, trachea, bronchi, etc., and more preferably to epithelial tissue in the oral cavity.

In the present invention, "administered or ingested together with an active ingredient" means that the oil-in-water emulsion of the present invention and the active ingredient are both administered or ingested within a time period during which they can coexist in the tissue at the application site. For example, the oil-in-water emulsion of the present invention and the active ingredient may be administered or ingested simultaneously in one composition, or they may be administered or ingested in separate forms and/or separate administration routes, either simultaneously or one after the other (preferably, the oil-in-water emulsion of the present invention, followed by the active ingredient). "Administration" is sufficient as long as the oil-in-water emulsion of the present invention and the active ingredient can be delivered to the tissue at the application site, and can be appropriately selected depending on the form and amount of the oil-in-water emulsion of the present invention and the active ingredient. For example, "administration" includes, but is not limited to, oral administration, spray administration, inhalation, nasal administration, oral administration, rectal administration, transdermal administration, and application. Preferably, "administration" is oral administration, spray administration, inhalation, oral administration, or application.

In the present invention, the "active ingredient" may be a water-soluble ingredient or an ingredient having affinity for the above-mentioned hydrophobic substance (e.g., lipophilic ingredient, etc.). The water-soluble ingredient is considered to be retained in the water in the oil-in-water emulsion of the present invention, preferably by bonding (e.g., hydrogen bonding) with the thickening polysaccharide and/or cyclodextrin. On the other hand, the ingredient having affinity for the above-mentioned hydrophobic substance is considered to be retained in the hydrophobic substance in the oil-in-water emulsion of the present invention. In the present invention, the "active ingredient" may be a component of taste in food and drink (salty ingredients such as sodium chloride and potassium chloride; sweet ingredients such as sugars (glucose, fructose, sucrose, maltose, oligosaccharides, isomerized sugar, etc.), sugar alcohols (xylitol, sorbitol, glycerin, erythritol, etc.), natural sweeteners (stevia, glycyrrhizin, thaumatin, etc.), and artificial sweeteners (aspartame, acesulfame potassium, sucralose, etc.). Flavor components: Sour components such as citric acid, succinic acid, lactic acid, tartaric acid, acetic acid, fumaric acid, malic acid, gluconic acid, and ascorbic acid; umami components such as glutamic acid, inosinic acid, and guanylic acid; alkaloids (caffeine, quinine, strychnine, theobromine, etc.), terpenes (limonoids, limonin, obacunone, nomilin, cucurbitacin, humulone, lupulone, etc.), glycosides (terpene glycosides, flavanone glycosides, nalidinone, naphthalene ... , neohesperidin, etc.), amino acids (tryptophan, phenylalanine, trypsin, arginine, valine, leucine, isoleucine, proline, etc.), bitter components such as casein and soy protein; pungent components such as capsaicin, piperine, sanshool, shogaol, gingerol, diallyl disulfide, p-hydroxybenzyl, isothiocyanate, etc.; astringent components such as tannin, catechin, theaflavin, thearubigin, etc. (not limited to these)) as well as food ingredients, seasonings, spices, etc. that contain them, and ingredients used for specific treatments and purposes in medicines (including quasi-drugs) and cosmetics (hereinafter referred to as "medicines, etc.") (for example, drugs, disinfectants, antibacterial agents, antibiotics, enzymes, antibodies, vitamins, minerals, amino acids, cooling agents, deodorants, moisturizers, fragrances, etc. (not limited to these)).

The retention agent of the present invention can be added to food, beverages, medicines, etc. to retain the active ingredients of the food, beverages, medicines, etc. The amount of the retention agent added may be any amount that can retain or maintain the active ingredients of the food, beverages, medicines, etc. in a predetermined location for a longer period than when the retention agent is not used, and can enhance and/or maintain the effect of the active ingredients for a longer period, and can be appropriately determined depending on the type and amount of the active ingredients, the type and form of the food, beverages, medicines, etc. For example, the retention agent of the present invention can be contained in the food, beverages, medicines, etc. in an amount of 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 2.5% by mass or more, 5% by mass or more, or 7% by mass or more in terms of the amount of the hydrophobic substance, and the upper limit is not particularly limited, but can be, for example, 55% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, 20% by mass or less, or 10% by mass or less. The range of the amount of the retention agent of the present invention in foods, beverages, medicines, etc. can be expressed using two numerical values selected from the above lower and upper numerical values, respectively. For example, the retention agent of the present invention can be contained in foods, beverages, medicines, etc. in an amount appropriately selected from the ranges of 0.5% to 55% by mass, 0.5% to 50% by mass, 0.5% to 40% by mass, 0.5% to 20% by mass, or 0.5% to 10% by mass, in terms of the amount of hydrophobic substance. If the amount of the retention agent of the present invention contained in foods, beverages, medicines, etc. is less or more than the above range, in either case, it may not be possible to retain the active ingredient in the form of use for the intended application.

In this specification, the amount of each component contained in a food, drink, medicine, etc. is indicated in mass %, with the total mass of the liquid portion of the food, drink, medicine, etc. excluding the solution or solid portion (for example, in the case of a food, drink, the amount of the liquid portion such as sauce or soup excluding ingredients) being 100 mass %. When the food, drink, medicine, etc. is in a liquid form or in a form that does not have a liquid portion, the amount can be the amount in a solution prepared by adding/adding to an appropriate solvent (for example, water, hot water, saline, buffer solution, etc.) at the time of administration or ingestion, or the amount in a solution in which the food, drink, medicine, etc. is dissolved in water (for example, body fluids such as saliva) in the tissue at the application site.

Foods, beverages, medicines, etc. may contain the retention agent of the present invention together with the active ingredient (e.g., in one composition), or the retention agent of the present invention and the active ingredient may be in separate forms (e.g., in two or more compositions that are administered or ingested together).

The form of the food, beverage, medicine, etc. can be appropriately selected according to the form of use in the intended application (for example, the form of a specified product, etc.), and can take any form, such as solid, powder, granules, flakes, chewable tablets, sheets, films, chewing gums, liquids, emulsions, semi-solid/semi-liquid (gels, sols, creams, pastes, mousses, etc.), soft capsules, etc. (but not limited to these). However, it is preferable that the retention agent of the present invention coexists with the active ingredient in the tissue at the application site in an amount within the above range. Depending on the form of the food, beverage, medicine, etc., an appropriate solvent (for example, water, hot water, saline, buffer solution, etc.) can be added/added to an appropriate solvent at the time of administration or ingestion as necessary to adjust the content of the retention agent of the present invention in the food, beverage, medicine, etc. to the above range, and then administered or ingested (such forms of food, beverage, medicine, etc. include, but are not limited to, solid, powder, granules, flakes, liquids, emulsions, semi-solid/semi-liquid (gels, sols, creams, pastes, mousses, etc.)). Alternatively, the food, beverage, medicine, etc. may be allowed to act by dissolving the retention agent of the present invention and the active ingredient in the moisture (e.g., body fluids such as saliva) in the tissue at the application site, and setting the content of the retention agent of the present invention within the above range (such forms of food, beverage, medicine, etc. include, but are not limited to, powder, granules, chewable tablets, sheets, films, chewing gum, etc.).

In addition to the retention agent and active ingredient of the present invention, foods, beverages, medicines, etc. can further contain, as necessary, ingredients that are normally used in the manufacture of the intended form of use (e.g., the form of a specified product, etc.) in an amount appropriate to the desired form of use, within a range that does not impair the effects of the present invention. Examples of such ingredients include excipients, disintegrants, lubricants, binders, diluents, buffers, suspending agents, thickeners, preservatives, antibacterial agents, preservatives, antioxidants, UV absorbers, colorants, pigments, dyes, pigments, lubricants, plasticizers, solvents, solubilizers, isotonicity agents, flavorings, fragrances, sweeteners, taste components, acidulants, seasonings, moisturizers, vitamins, surfactants, chelating agents, antibacterial agents, emulsifiers, water-soluble organic solvents, food ingredients, etc., but are not limited to these.

In one embodiment, the retention agent of the present invention is provided in a food or beverage. When the food or beverage is consumed, the oil-in-water emulsion in the retention agent of the present invention adheres to the epithelial tissue in the oral cavity, where it retains the active ingredients ingested therewith, such as taste ingredients, and/or absorbs, adsorbs and retains the taste ingredients, thereby retaining them, and the effect of the active ingredients (e.g., the flavor and taste brought about by the taste ingredients) can be enhanced and/or maintained for a longer period of time compared to when the retention agent is not used. The retention agent of the present invention in such a usage embodiment may also be referred to as a flavor enhancer or taste enhancer.

In another aspect, the "retention agent" of the present invention is provided in an oral care product. By holding the product in the mouth, the oil-in-water emulsion in the retention agent of the present invention adheres to the epithelial tissue in the oral cavity, where the active ingredient of the drug administered together (for example, caries prevention/repair agents (cetylpyridinium chloride (CPC), benzalkonium chloride, benzethonium chloride (BTC), sodium fluoride, sodium monofluorophosphate, etc.), gingivitis/periodontitis prevention/improvement agents (ε-aminocaproic acid, isopropylmethylphenol (cymen-5-ol), allantoin, dipotassium glycyrrhizinate, β-glycyrrhetinic acid, cetylpyridinium chloride (CPC), hinokitiol, triclosan, tranexamic acid, benzalkonium chloride, benzethonium chloride (BTC), triclosan, sodium chloride, tocopherol acetate, etc.), stomatitis prevention/improvement agents (allantoin, glycyrrhizic acid, tranexamic acid, etc.), and dentin hypersensitivity prevention/suppression agents (aluminum lactate, potassium nitrate, etc.)) , plaque prevention/removal agents (dextranase, etc.), tartar prevention/removal agents (sodium polyphosphate, sodium pyrophosphate, etc.), stain prevention/removal agents (sodium polyphosphate, polyethylene glycol, etc.), bad breath prevention/removal agents (isopropylmethylphenol (cymen-5-ol), sodium lauroyl sarcosine, etc.), dry mouth prevention/suppression agents (hyaluronic acid, milk protein extract, lactoperoxidase, glucose oxidase, lysozyme, lactoferrin, dipotassium phosphate, potassium chloride, calcium chloride hydrate, sodium chloride, magnesium chloride, pilocarpine hydrochloride, cevimeline hydrochloride hydrate, anethole trithione, etc.), but are not limited to these), and/or by absorbing/adsorbing and retaining the drug, the effect of the drug can be enhanced and/or maintained for a longer period of time compared to when the retention agent is not used. Such oral care products can be in the conventional forms known in the art, such as mouthwash, mouth rinse, mouthwash, liquid dentifrice, toothpaste, powdered dentifrice, gel, film, chewing gum, spray, liquid, etc.

In another embodiment, the "retention agent" of the present invention is provided in a hair care product. By applying the product to hair, the oil-in-water emulsion in the retention agent of the present invention adheres to the hair, and the co-administered active ingredients, such as hair protection ingredients (hydrolyzed eggshell membrane, hydrolyzed keratin, hydrolyzed collagen, hydrolyzed silk, hydrolyzed wheat, hydrolyzed wheat protein, hydrolyzed soy protein, glutamic acid, arginine, pyrrolidone carboxylic acid, dimethicone, amodimethicone, polyquaternium-10, chitosan, etc.), hair quality improvement ingredients (stearyltrimonium bromide, cetrimonium bromide, stearyltrimonium chloride, etc.), hair repair ingredients (olive oil, jojoba oil, avocado oil, squalane, isopropyl myristate, isostearyl alcohol, oleyl alcohol, egg yolk fatty oil, adsorbed refined lanolin, soybean oil, etc.), and the like, are dissolved in the hair. By retaining and/or absorbing/adsorbing and retaining active ingredients such as (but not limited to) moisturizing ingredients (hyaluronic acid, glycerin, hydrolyzed eggshell membrane, hydrolyzed keratin, hydrolyzed collagen, hydrolyzed silk, hydrolyzed wheat, hydrolyzed wheat protein, hydrolyzed soy protein, glutamic acid, arginine, pyrrolidone carboxylic acid, egg yolk fatty oil, adsorbed refined lanolin, soybean sterol, cholesterol, ceramide, etc.), the effect of the active ingredient can be enhanced and/or maintained for a longer period of time compared to when the retention agent is not used. Such hair care products can be in the conventional general forms known in the art, such as shampoos, rinses, conditioners, treatments, etc.

The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Experiment 1: Evaluation of emulsion stability of oil-in-water emulsions (1) Preparation of oil-in-water emulsions Oil-in-water emulsions were prepared by adding and mixing each component according to the composition in Table 1 below. Oil (canola oil) was used as the hydrophobic substance, and carboxymethylcellulose (CMC), glucomannan, guar gum, κ-carrageenan, tamarind gum, gellan gum, xanthan gum, ι-carrageenan, locust bean gum, λ-carrageenan were used as thickening polysaccharides, and either carboxyvinyl polymer or sodium polyacrylate, which are non-polysaccharide thickening agents, was used as a control.

Each component was mixed at once and stirred for 10 minutes at 20,000 rpm using a hand blender. Each resulting oil-in-water emulsion (50 mL) was transferred to a conical tube (Falcon (registered trademark) conical tube 50 mL) and centrifuged at 3000 rpm for 1 minute. The thickness (depth) of the aqueous phase, micelles, and oil phase was then visually observed and the proportion (%) of each phase was measured to evaluate the emulsion stability of each composition. The evaluation was performed with a micelle proportion of 100% as "◎", a micelle proportion of 70% or more but less than 100% as "◯", and a micelle proportion of less than 70% as "X".

The amount of each component in the table below is shown in mass %, with the amount of the obtained oil-in-water emulsion being 100 mass %. Food additives (food grade) were used for the fats and oils, α-cyclodextrin, and thickening polysaccharides.

(2) Results The thickening polysaccharides added to the oil-in-water emulsions, the measured ratios of each phase, and the evaluation results are shown in Table 2. It is possible to form an oil-in-water emulsion by adding and mixing a thickening polysaccharide together with water, a hydrophobic substance, and α-cyclodextrin. As is clear from the above results, when carboxymethylcellulose (CMC), glucomannan, guar gum, κ-carrageenan, tamarind gum, gellan gum, xanthan gum, ι-carrageenan, locust bean gum, and λ-carrageenan were used as thickening polysaccharides, the micellar phase of the oil-in-water emulsion was maintained even under the above conditions, and it was confirmed that the emulsion showed particularly high emulsion stability. In particular, when CMC, glucomannan, tamarind gum, and xanthan gum were added, separation of the aqueous phase and the oil phase was not observed, and remarkably high emulsion stability was confirmed. On the other hand, it was confirmed that the addition of a non-polysaccharide thickener caused significant separation of the aqueous phase and the oil phase under the above conditions, resulting in relatively low emulsion stability.

Each component was added and mixed according to the composition in Table 3 below to prepare an oil-in-water emulsion. As a hydrophobic substance, one of carnauba wax, petrolatum wax (white petrolatum), rosin, and silicone oil, containing 1% oil red, was used, and xanthan gum was used as a thickening polysaccharide. The amount of each component in the table is shown in mass %, with the amount of the obtained oil-in-water emulsion being 100 mass %.

The components were mixed and stirred in the same manner as above, and each resulting oil-in-water emulsion (50 mL) was transferred to a conical tube (Falcon (registered trademark) conical tube 50 mL) and centrifuged at 3000 rpm for 1 minute. The thickness (depth) of the aqueous phase, micelles, and oil phase was then visually observed, and the proportion (%) of each phase was measured, and the emulsion stability of each composition was evaluated in the same manner as above.

The hydrophobic substances added to the oil-in-water emulsion, the measured ratios of each phase, and the evaluation results are shown in Table 4. These results demonstrate that oil-in-water emulsions can be formed using not only oils and fats, but also other hydrophobic substances, and that the micellar phase of the oil-in-water emulsion is maintained even under the above conditions, resulting in high emulsion stability.

Experiment 2: Evaluation of the interaction between α-cyclodextrin and thickening polysaccharide in oil-in-water emulsion To evaluate the interaction between α-cyclodextrin and thickening polysaccharide in an aqueous solution, the enthalpy change (ΔH) was determined by isothermal titration calorimetry (ITC) according to a conventionally known method. That is, using an isothermal titration calorimeter (NANO ITC SV; TA Instruments), 10 μL of a thickening polysaccharide aqueous solution (0.05 g/100 mL) was dropped every 180 seconds for 25 times (75 minutes) into an aqueous solution of α-cyclodextrin (25 g/100 mL), and the enthalpy value (μJ) was determined from the area of the 25th (final) titration peak. As controls, enthalpy values (μJ) were similarly determined using non-polysaccharide thickeners, carboxyvinyl polymer and sodium polyacrylate.

The results are shown in Table 5. A positive enthalpy value, i.e., an endothermic reaction, was observed when thickening polysaccharides (CMC and xanthan gum), which showed particularly high emulsion stability in Experiment 1 above, were used. This result suggests the existence of an interaction between the thickening polysaccharide and α-cyclodextrin via hydration water; for example, it is thought that some of the water molecules hydrated in the thickening polysaccharide form hydrogen bonds with α-cyclodextrin. Normally, the hydrogen bonds formed between water molecules are shorter in distance and have a higher energy value than the hydrogen bonds formed between the thickening polysaccharide and α-cyclodextrin, which cause intermolecular repulsion due to charged sites. For this reason, it is thought that when some of the water molecules hydrated in the thickening polysaccharide form hydrogen bonds with α-cyclodextrin, an endothermic reaction occurs as a result of the subtraction of energy values. The transfer of heat (positive enthalpy value) suggests the presence of an interaction between the thickening polysaccharide and α-cyclodextrin, and this interaction is thought to be the factor that produces high emulsion stability in the oil-in-water emulsion in Experiment 1 above.

Experiment 3: Performance evaluation of oil-in-water emulsions (flavor enhancement)
(1) Evaluation of the flavor of the oil-in-water emulsion itself Oil-in-water emulsions were prepared by adding and mixing each component according to the composition in Table 6. Each component was mixed at once and stirred with a hand blender at 20,000 rpm for 10 minutes.

The amount of each component in the table is shown in mass %, with the amount of the resulting oil-in-water emulsion being 100 mass %.

As a control, a mixture was used that was prepared by mixing the ingredients other than the oil and fat according to the composition in Table 6 below, adding the oil and fat, and then mixing by hand without applying shear force (i.e., not forming an oil-in-water emulsion).

The resulting oil-in-water emulsion and the control mixture were each added to water in an amount of 1% by mass, and the presence or absence of flavor in each solution was evaluated by a panel of well-trained experts through a sensory test.

The results showed that neither the oil-in-water emulsion nor the control mixture had a different odor than plain water.

When the control mixture was ingested, it had a slight sticky feeling due to the oil compared to water, but no difference in taste was detected.

When the oil-in-water emulsion was ingested, it felt like the entire oral cavity was widely covered (the oil-in-water emulsion was attached) compared to water, but no difference in taste was detected. The amount of fats and oils contained in the 1% by mass oil-in-water emulsion solution was only about 0.13% by mass, and it was confirmed that no taste or smell derived from fats and oils was detected.

(2) Effect of flavor enhancement by combined use of oil-in-water emulsion I
To the 1% by mass oil-in-water emulsion solution obtained above and the 1% by mass control mixture solution, a predetermined amount of each taste component listed in Table 7 below was added to each solution to prepare samples for flavor evaluation (hereinafter, the sample containing 1% by mass oil-in-water emulsion solution will be referred to as "1% O/W(+)" and the sample containing 1% by mass control mixture solution will be referred to as "1% O/W(-)"). Furthermore, as a control, an aqueous solution in which only the same amount of each taste component was added to water (hereinafter, referred to as "control aqueous solution") was used.

Each sample (10 mL) was consumed in the order of evaluation described in Table 7 below, and the intensity of each taste was evaluated by a well-trained panel of experts on a 10-point scale, with the control aqueous solution being rated as 5. Rinsing was performed twice with 20 mL of water.

The evaluation results for the intensity of each taste for each sample are shown in Table 8 below (sweetness, umami, sourness, bitterness: N=4, saltiness: N=3).

These results confirm that by including flavor components in an oil-in-water emulsion (1% O/W (+)), the intensity of each flavor is significantly increased. When flavor components were included in a mixture that did not form an oil-in-water emulsion (1% O/W (-)), there was also a tendency for the flavor intensity to increase slightly, but the degree of increase was slight.

In addition, for 1% O/W (+) and 1% O/W (-), the change in taste intensity over one minute after ingestion of each sample was evaluated by well-trained expert panelists using the Time Intensity (TI) method with the sensory evaluation software FIZZ (Biosystemes). The results are shown in Figure 1 (sweetness: N=4, saltiness/bitterness: N=5, sourness/umami: N=3; the results in Figure 1 show the average values of the results for each panelist).

The results in Figure 1 confirm that, compared to 1% O/W (-), 1% O/W (+) achieved higher values in one or more of the following: onset of each flavor immediately after consumption, intensity, thickness of the middle flavor, and persistence of aftertaste.

(3) Effect of flavor enhancement by combined use of oil-in-water emulsion II
Oil-in-water emulsions were prepared by adding and mixing each component according to the composition in Table 9. The thickening polysaccharides used were xanthan gum, gum arabic, pectin, phosphate cross-linked starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, tragacanth gum, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl cellulose. Each component was mixed at once and stirred with a hand blender at 20,000 rpm for 10 minutes.

The amount of each component in the table is shown in mass %, with the amount of the resulting oil-in-water emulsion being 100 mass %.

As a control, a mixture was used that was prepared by mixing the ingredients other than the oil and fat according to the composition in Table 9 below, adding the oil and fat, and then mixing by hand without applying shear force (i.e., not forming an oil-in-water emulsion).

The resulting oil-in-water emulsion and the control mixture were each added to water in an amount of 1% by mass to prepare a 1% oil-in-water emulsion solution and a 1% control mixture solution. To each solution, salt was added in an amount of 0.6% by mass to prepare samples for flavor evaluation (hereinafter, the sample containing 1% oil-in-water emulsion solution will be referred to as "1% O/W(+)" and the sample containing 1% control mixture solution will be referred to as "1% O/W(-)"). As a control aqueous solution, an aqueous solution in which salt was added to water in an amount of 0.6% by mass was used.

Each sample (10 mL) was consumed in the order of evaluation described in Table 7 above, and the intensity of each taste was evaluated by a well-trained panel of experts on a 10-point scale, with the control aqueous solution being rated as 5. Rinsing was performed twice with 20 mL of water.

The evaluation results for the intensity of each taste for each sample are shown in Table 10 below (N=3).

These results confirmed that regardless of the type of thickening polysaccharide used, the flavor intensity was significantly increased by including an oil-in-water emulsion (1% O/W(+)).

(4) Effect of Concomitant and Repeated Ingestion of Oil-in-Water Emulsion A 1% O/W(+) containing flavor components (0.6% by mass salt or 0.2% by mass caffeine) prepared in the same manner as in (2) above was ingested four times in succession (without rinsing) (10 mL each), and the intensity of each flavor was evaluated on a 10-point scale, with the first intake being evaluated as 5. The evaluation was performed by well-trained expert panelists.

The evaluation results for the intensity of each taste for each sample are shown in Table 11 below (salty: N=4, bitter: N=3).

These results confirmed that in both cases, the taste intensity gradually increased with repeated ingestion of a sample containing an oil-in-water emulsion. This is thought to be because the taste components adhere to and accumulate in the oral cavity along with the oil-in-water emulsion.

(5) Effect of additional use of oil-in-water emulsion on flavor enhancement I
The oil-in-water emulsions prepared in (1) above were each added to water in an amount of 10% by mass to obtain a 10% by mass aqueous solution of the oil-in-water emulsion not containing taste components (hereinafter referred to as "10% O/W(+)"). A 0.6% by mass saline solution was used as the aqueous solution to which taste components were added (hereinafter referred to as "taste aqueous solution").

For the evaluation, the taste solution (10 mL) was ingested, the taste intensity was evaluated (before application), the mouth was washed (rinsed twice with 20 mL of water), and then 10% O/W (+) (10 mL) was held in the mouth for 30 seconds and applied to the oral cavity, after which it was spat out, the mouth was washed (rinsed twice with 20 mL of water), and then the taste solution (10 mL) was ingested again and the taste intensity was evaluated (after application). The evaluation was carried out by well-trained expert panelists on a 10-point scale, with 5 being the rating of the taste solution before application.

The evaluation results obtained are shown in Table 12 below (N=4).

Furthermore, the change in taste intensity over one minute after ingesting each taste solution before and after application of the oil-in-water emulsion was evaluated by well-trained expert panelists using the Time Intensity (TI) method with sensory evaluation software FIZZ (Biosystemes). The results are shown in Figure 2 (N=4).

These results confirmed that the flavor intensity was increased simply by ingesting the flavor aqueous solution after applying the oil-in-water emulsion to the oral cavity without mixing the flavor components into the aqueous solution of the oil-in-water emulsion beforehand. In addition, as shown in Figure 2, it was confirmed that when the flavor aqueous solution was ingested after applying the oil-in-water emulsion, high values were obtained for the onset of flavor immediately after consumption, flavor intensity, thickness of the middle taste, and persistence of the aftertaste. This is thought to be because the flavor components adhere to and accumulate in the applied oil-in-water emulsion and act.

(6) Effect of additional use of oil-in-water emulsion on flavor enhancement II
The components of each taste listed in Table 13 below were added to water in a predetermined amount to prepare a taste solution, and the taste intensity of each taste solution was evaluated before and after application to the oral cavity at 10% O/W(+) in the same manner as in the evaluation method described in (5) above. The evaluation was performed by well-trained expert panelists on a 10-point scale, with 5 being the evaluation of the taste solution before application.

The evaluation results obtained are shown in Table 13 below (N=2).

These results confirmed that for all five basic tastes, the taste components were not mixed into the aqueous solution of the oil-in-water emulsion beforehand, but rather the taste intensity was increased by simply ingesting the aqueous taste solution after applying the oil-in-water emulsion to the oral cavity.

(7) Effect of enhancing the flavor of pungent components by the combined use of oil-in-water emulsion The above five basic tastes are all sensed by the gustatory nerves. On the other hand, pungent taste, astringent taste, etc. are not sensed by the gustatory nerves but by pain and temperature senses, and are therefore distinct from the above taste components. Therefore, we confirmed whether the combined use of oil-in-water emulsion could have a similar effect on components other than taste components.

According to the composition in Table 14 below, each component was added and mixed to prepare an oil-in-water emulsion containing the pungent component in the oil. As thickening polysaccharides, xanthan gum, gum arabic, pectin, phosphate cross-linked starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, tragacanth gum, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl cellulose were used, and each component was mixed at once and stirred for 1 minute at 20,000 rpm using a Polytron homogenizer.

The amount of each component in the table is shown as a mass % amount, with the amount of the obtained oil-in-water emulsion being 100 mass %.
Chili oil was used as a control.

For the evaluation, a panel of well-trained experts ingested each sample (10 mL) and rated the intensity of each flavor on a 10-point scale, with the control being rated 5. The results are shown in Table 14, and each value represents the average (N=3).

The results confirmed that all oil-in-water emulsions containing pungent ingredients had a stronger spiciness than the control, regardless of the type of thickening polysaccharide used. In addition, it was confirmed that the spiciness of the oil-in-water emulsions containing pungent ingredients lasted for more than 10 minutes after ingestion, while the spiciness felt after ingestion of the control disappeared within about 2 minutes.

These results confirm that it is possible to increase the effect (strength) and duration of effects by using oil-in-water emulsions in combination with ingredients other than taste ingredients, as well as ingredients in oils and fats.

(8) Comparative Example An emulsion composition was prepared by adding and mixing each component according to the composition in the following Table 15. The components were mixed using a Polytron homogenizer at 20,000 rpm for 1 minute.

The evaluation was carried out by dividing the samples into sets of Comparative Example A and Comparative Example B, and it was confirmed whether the emulsion compositions (A-2, B-2) had a stronger salty taste than the emulsion compositions (A-1, B-1) that did not contain α-cyclodextrin or a thickening polysaccharide (xanthan gum).

For the evaluation, well-trained expert panelists (N=3) ingested each emulsion composition (A-1, B-1) (10 mL), evaluated the intensity of the flavor, washed their mouths (rinsed twice with 20 mL of water), and then ingested each emulsion composition (A-2, B-2) to evaluate and compare the intensity of the flavor.

In Comparative Example A, both Comparative Example A-1 and Comparative Example A-2 had a butter-like shape and had almost no noticeable salty taste. Comparing Comparative Example A-1 and Comparative Example A-2, no difference was observed in the intensity of the salty taste between the two.

In Comparative Example B, both Comparative Example B-1 and Comparative Example B-2 were insufficiently emulsified, and oil floating was observed. In both Comparative Example B-1 and Comparative Example B-2, a salty taste was felt, but it did not linger, and no difference was observed in the strength of the salty taste between the two.

Experiment 4: Performance evaluation of oil-in-water emulsions (enhancement of hair care effects)
Each component was added and mixed according to the composition in Table 16 below to prepare an oil-in-water emulsion. Each component was mixed at once and stirred for 10 minutes at 20,000 rpm using a hand blender. The amount of each component in the table is shown in mass %, with the amount of the obtained oil-in-water emulsion being 100 mass %.

The obtained oil-in-water emulsion was added to a commercially available hair conditioner (TSUBAKI Premium Moist Hair Conditioner (Fine Today Co., Ltd.)) in an amount of 25% by mass to prepare a hair conditioner containing an oil-in-water emulsion. As a control, the above commercially available hair conditioner containing no oil-in-water emulsion was used.

After washing the hair with hair shampoo, the hair was rinsed thoroughly with hot water of about 40°C, and then about 10 g of the hair conditioner containing an oil-in-water emulsion or the control hair conditioner was taken in the palm of the hand and thoroughly applied to the entire hair and left for about 1 minute. The hair was then rinsed thoroughly with hot water of about 40°C, and the moisture was removed with a towel and dried with a hair dryer. The texture of the hair was then evaluated by a panel (N=3).

The results showed that when the control hair conditioner was used, the hair felt very smooth and shiny, but due to static electricity repulsion the hair was less manageable and frizz was observed.

On the other hand, when the hair conditioner containing the oil-in-water emulsion was used, the hair felt very smooth and shiny, just like when the control hair conditioner was used, but it also felt moisturized and smooth, and the hair was easy to manage and no static flyaways were observed. This result is thought to be because the inclusion of an oil-in-water emulsion allows the active ingredients in the hair conditioner to remain in the hair longer, enhancing and/or prolonging the effects of the active ingredients, thereby enhancing the moisturizing effect, reducing the surface electric potential of the hair that affects flyaways, and further reducing the repulsion between hair strands.

As described above, the oil-in-water emulsion of the present invention can adhere to a specific site, retain and/or absorb/adsorb the active ingredient, and retain it, thereby enhancing and/or prolonging the effect of the active ingredient. It is expected that the emulsion will be used as a retention agent for active ingredients in various fields, such as food and beverages, pharmaceuticals, and cosmetics.

Claims (11)

Retention agents used to retain active ingredients include oil-in-water emulsions containing water, a hydrophobic material, cyclodextrin, and a thickening polysaccharide. The retention agent according to claim 1, wherein the hydrophobic substance is one or more selected from the group consisting of oils and fats, hydrophobic waxes, and hydrophobic resins. The retention agent according to claim 1, wherein the thickening polysaccharide is one or more selected from the group consisting of carboxymethylcellulose (CMC), xanthan gum, locust bean gum, guar gum, glucomannan, κ-carrageenan, ι-carrageenan, λ-carrageenan, tamarind gum, gellan gum, gum arabic, pectin, phosphate cross-linked starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, tragacanth gum, hydroxypropyl cellulose, methyl cellulose, hydroxypropyl methyl cellulose, and hydroxyethyl cellulose. The retention agent according to claim 1, which is added to food and beverages. The retention agent according to claim 1, which is added to a pharmaceutical product. The retention agent according to claim 1, which is added to cosmetics. A method for producing a retention agent used to retain an active ingredient, comprising the step of mixing water, a hydrophobic substance, cyclodextrin, and a thickening polysaccharide to form an oil-in-water emulsion. A food or drink containing a retention agent used to retain an active ingredient, the retention agent including water, a hydrophobic substance, cyclodextrin, and an oil-in-water emulsion containing a thickening polysaccharide, in an amount of 0.5% by mass to 55% by mass of the hydrophobic substance. A pharmaceutical product comprising a retention agent used to retain an active ingredient, the retention agent including an oil-in-water emulsion containing water, a hydrophobic substance, cyclodextrin, and a thickening polysaccharide, in an amount of 0.5% to 55% by mass of the hydrophobic substance. A cosmetic product comprising a retention agent used to retain an active ingredient, the retention agent including an oil-in-water emulsion containing water, a hydrophobic substance, cyclodextrin, and a thickening polysaccharide, in an amount of 0.5% to 55% by mass in terms of the amount of the hydrophobic substance. The use of an oil-in-water emulsion containing water, a hydrophobic substance, cyclodextrin, and a thickening polysaccharide in a method for producing a retention agent used to retain an active ingredient.