Oil-in-water emulsions containing an emulsifier system consisting of cyclodextrin and a starch-derived emulsifier

Abstract

The present application relates to oil-in-water emulsions of natural origin, obtained with an emulsifier system consisting of a cyclodextrin and a starch-based emulsifier and / or a starch-derived emulsifier, preferably natural β-cyclodextrin and octenyl succinate-modified pregelatinized hydrolyzed starch. These emulsions have the advantage of having a viscosity that can be adjusted from 3000 mPa·s to less than 10 mPa·s, making it possible to obtain various forms ranging from gels to milks and fluid lotions. These emulsions are suitable for use in cosmetics, dermatological products, veterinary products, and pharmaceuticals. In particular, in cosmetics, these emulsions can be used in skin care, hair care, oral care, hygiene, and makeup.

Description

[Technical Field]

[0001] The present invention relates to the field of oil-in-water emulsions, in particular cosmetic or dermatological emulsions, in which the emulsifying surfactants are predominantly of natural origin, and may also be entirely of natural origin. [Background technology]

[0002] Regarding the emulsifying properties of cyclodextrins and starch-derived emulsifiers, separately, the prior art teaches that cyclodextrins are emulsifiers capable of forming Pickering oil-in-water emulsions, which are emulsions stabilized by insoluble microparticles, and also that starch-derived emulsifiers, such as octenyl succinate starch, are emulsifiers capable of forming Pickering or conventional oil-in-water emulsions stabilized by amphiphilic molecules containing hydrophobic and hydrophilic moieties.

[0003] While conventional emulsions are stabilized by surfactants and amphiphilic molecules containing hydrophobic and hydrophilic moieties that are located at the interface between water and oil, reducing the interfacial tension, Pickering emulsions are stabilized without surfactants by very fine particles (not molecules) such as silica, talc, or granular starch, which are insoluble, solid, colloidal, do not affect the interfacial tension, and irreversibly adsorb to the interface of emulsion droplets, imparting long-term stability to the emulsion.

[0004] Regarding the combination of cyclodextrin with another emulsifier, Henkel's patent application WO 2008 / 003685 teaches associating cyclodextrin with a hydrophobically modified polysaccharide, preferably a modified cellulose, particularly hydroxypropylmethylcellulose. The hydrophobically modified polysaccharide proposed is cellulose alone. The proposed emulsifier system can form a stable oil-in-water emulsion with little or no low molecular weight surfactant to reduce or avoid skin irritation, dehydration, and redness. The application also proposes adding modified starch in addition to the cyclodextrin and hydrophobically modified polysaccharide, but does not specify the nature of the modification of the starch.

[0005] Chinese Patent No. 112759772 from Wuhan Polytechnic University proposes a method for preparing Pickering emulsions, which includes preparing octenyl succinate starch from granular millet starch, subsequently adding β-cyclodextrin to the starch milk prepared using the octenyl succinate millet starch, and finally adding a medium-chain triglyceride. This patent specifies that the cyclodextrin content in the aqueous phase is preferably 1-3% by weight of the aqueous phase, but does not mention the selection of the octenyl succinate millet starch content in either the aqueous phase or the fat phase. This patent states that the octenyl succinate starch is prepared in the form of a starch milk, i.e., to those skilled in the art, the starch is dispersed in water, not solubilized. The ability of this millet starch to form Pickering emulsions, as known in the literature, is essentially due to a combination of octenyl succinate modification and very small starch particle size. This mechanism is described, for example, by Li et al. in the article "Starch granules as Pickering emulsifiers: role of octenyl succinylation and particle size" in the journal Food Chemistry 2019, vol. 283, pages 437-444. Furthermore, the viscosity of the emulsion disclosed in Chinese Patent No. 112759772 is very high, exceeding 0.1 s. -1 These viscosity values ​​are incompatible with obtaining thin to fluid, or even very fluid, emulsions according to the present invention.

[0006] Beiersdorf's European Patent Application No. 1923044 discloses a cosmetic emulsion containing three compounds: a cellulose ether, a water-soluble carbohydrate, and a water-insoluble modified starch. Cyclodextrin is one possible water-soluble carbohydrate, but is not preferred and is not listed as an example. Maltodextrin is preferred. Possible modified starches include octenyl succinate starch, with the preferred modified starch being the aluminum salt of octenyl succinate starch. All emulsions proposed and disclosed by this application contain the three compounds together.

[0007] technical issues Oil-in-water emulsions, which are widely used in cosmetics and dermatology, are obtained by mixing an oil phase with an aqueous phase in the presence of one or more emulsifying surfactants.Historically, since the advent of petrochemicals, these emulsifying surfactants have been molecules obtained by chemical synthesis exclusively from petrochemical-derived raw materials.Despite their excellent performance in emulsifying and stabilizing a wide variety of emulsions, the discovery that some of them are harmful in the medium for a long time and the pollution associated with their production and release into the environment has led the cosmetic market to move toward emulsions that contain little or no of these emulsifying surfactants of petrochemical origin.

[0008] Naturally derived emulsifying surfactants have been known for several years and are used in cosmetic emulsions as partial or total substitutes for petrochemically derived emulsifying surfactants. However, the physical quality of emulsions obtained using such naturally derived emulsifying surfactants is rarely at the same level as that of emulsions obtained using petrochemically derived emulsifying surfactants. Among the desired qualities, viscosity, emulsion stability during storage, and sensory properties are the three most important. The target values ​​for these qualities can vary depending on the target market, both in terms of application and country, and on consumer demands. For example, emulsions in gel form may be preferred for certain products, such as moisturizing products, while emulsions in the form of concentrated or fluid milks may be preferred for other products, such as sunscreens or after-sun care products. Gels generally have viscosities of several thousand mPa·s, while concentrated milks have viscosities of less than 1,000 mPa·s, or even less than 500 mPa·s, and even close to 100 mPa·s, and fluid milks have viscosities of several tens of mPa·s.

[0009] Therefore, cosmetic manufacturers need emulsions derived from naturally occurring emulsifying surfactants whose viscosity can be adjusted to prepare products that meet these preferences. It would also be an economic and ecological advantage if this need could be met using the same emulsifying surfactant, or at least using a mixture of naturally occurring molecules and / or polymers to obtain different viscosities. This is the main objective of the present application, namely, an oil-in-water emulsion comprising an emulsifier system consisting of cyclodextrin and a starch-derived emulsifier. Summary of the Invention

[0010] According to a first object, the present invention provides an oil-in-water (O / W) emulsion comprising: an oil phase dispersed in an aqueous phase; an emulsifier system consisting of at least one cyclodextrin and at least one starch-based emulsifier and / or starch-derived emulsifier, the emulsion has a Brookfield viscosity of less than 3,000 mPa.s, preferably 2,800 mPa.s or less, preferably 2,600 mPa.s or less, at 20 rpm using an SP5 spindle at 20°C for 1 minute; The starch-based emulsifiers and / or emulsifiers derived from starch relate to O / W emulsions having a solubility in water at 22°C according to Test A of 50% or more, or 75% or more, or 85% or more, or 95% or more, or 98% or more, or 99% or more, or 100%.

[0011] In an embodiment, the O / W emulsion according to the invention further comprises the following features: the emulsion has a Brookfield viscosity at 20 rpm at 20°C for 1 minute using an SP1 spindle of more than 10 mPa.s, preferably 20 mPa.s or more, preferably 30 mPa.s or more, preferably 50 mPa.s or more, the emulsion is biodegradable to more than 90%, in particular to more than 93%, according to OECD standard 301 F; the emulsion comprises less than 1% by weight, preferably less than 0.5% by weight, preferably 0% by weight of surfactants having a molecular weight or weight average molecular weight of less than or equal to 250 Da, preferably less than or equal to 500 Da, preferably less than or equal to 750 Da, preferably less than or equal to 1 kDa, preferably less than or equal to 10 kDa, the at least one cyclodextrin is selected from natural and modified cyclodextrins, preferably from natural or modified α-, γ- or β-cyclodextrins, more preferably from natural α-, γ- or β-cyclodextrins, most preferably natural β-cyclodextrin; the starch-based emulsifier or emulsifier derived from starch is a starch, a dextrin or a maltodextrin, in particular a starch, the starch-based emulsifier and / or emulsifier derived from starch has a solubility in water at 22°C according to test A of 50% or more, or 75% or more, or 85% or more, or 95% or more, or 98% or more, the at least one starch-based emulsifier and / or starch-derived emulsifier comprises at least one amphiphilic group, preferably at least one alkenyl succinate group, preferably at least one alkali metal or alkaline earth metal octenyl succinate group, most preferably at least one sodium or calcium octenyl succinate group; the starch is a starch modified by pregelatinization, gelatinization, spray drying, acid hydrolysis or enzymatic hydrolysis, or a combination of these modifications, preferably the starch is a hydrolyzed and pregelatinized starch, the starch-based or starch-derived emulsifier is selected from octenylsuccinate granular starch, octenylsuccinate pregelatinized starch, octenylsuccinate gelatinized starch, octenylsuccinate hydrolyzed starch, octenylsuccinate hydrolyzed and pregelatinized starch, octenylsuccinate dextrin, octenylsuccinate maltodextrin, and mixtures thereof; the ratio of the mass of the starch-based emulsifier or emulsifier derived from starch to the mass of the cyclodextrin is in the range of 0.2 to 2, preferably 0.3 to 1.6, preferably 0.4 to 1.2, preferably 0.5 to 1, preferably 0.55 to 0.9, most preferably 0.60 to 0.80, the mass content of the emulsifier system in the emulsion is ≥ 0.5% by weight, preferably ≥ 1% by weight, preferably ≥ 1.5% by weight, preferably ≥ 2% by weight, preferably ≥ 2.5% by weight, preferably ≥ 3% by weight, preferably ≥ 3.5% by weight, preferably ≥ 4% by weight, preferably ≥ 4.5% by weight, preferably ≥ 5% by weight, the mass content of the emulsifier system relative to the total weight of the emulsion is at most 18% by weight, at most 10% by weight, at most 9% by weight, at most 8% by weight, at most 7% by weight, at most 6.5% by weight, and most preferably at most 6% by weight, the mass content of at least one cyclodextrin relative to the total weight of the emulsion is in the range of 0.25% to 9%, 0.5 to 8%, 1.5 to 7%, 2 to 7%, 2.5 to 6%, 3 to 5% and most preferably 3.5 to 4.5% by weight of said emulsion, the mass content of at least one starch-based and / or starch-derived emulsifier relative to the total weight of the emulsion is in the range of 0.25-9 wt.-%, 0.5-8 wt.-%, 1-7 wt.-%, 1.5-6 wt.-%, 2-5 wt.-%, most preferably 2.5-4.5 wt.-%, the mass content of the oil phase relative to the total weight of the emulsion is in the range of 5 to 50 wt.%, 15 to 45 wt.%, 20 to 40 wt.%, 25 to 35 wt.%, the oil phase consists of at least one oil chosen from oils of natural origin, in particular vegetable oils, mineral oils, silicones, preferably the oil phase consists of at least one oil of natural origin, in particular vegetable oils, The emulsion further comprises at least one rheological agent, preferably a hydrophilic and / or hydrophobic thickener, preferably a hydrophilic thickener.

[0012] According to a second aspect, the present invention relates to a cosmetic, dermatological or pharmaceutical composition comprising an oil-in-water emulsion according to the invention.

[0013] In embodiments, the cosmetic, dermatological or pharmaceutical composition further comprises one or more of the following features: a skin care product, a hair care product, an oral care product, a make-up product or a hygiene product, preferably a skin care product, a hair care product, an oral care product or a make-up product, - a skin care product selected from moisturizers, sunscreens, and after-sun products; - a hair care product selected from moisturizing hair care products, conditioners, smoothing products and colorants, - an oral care product selected from toothpaste and mouthwash, - a makeup product selected from foundation, mascara, eye shadow and lipstick, -A hygiene product selected from cleansing creams.

[0014] The present invention has several advantages.

[0015] One of the advantages of the emulsions encompassed by the present application is that they contain ingredients of substantially, if not exclusively, natural origin. The natural origin of ingredients used to formulate products for everyday applications, such as cosmetic compositions, is currently a major issue, not only for environmental protection and conservation, but also for consumer health. In this regard, the emulsions according to the present application contain small amounts or no traditional emulsifiers of petrochemical origin, particularly glycol derivatives and ethoxylated and polyethoxylated derivatives, which are now being sought to replace for environmental (low biodegradability) and safety (ethylene oxide is toxic and flammable) reasons.

[0016] The emulsion also has the advantage that it can be prepared by a low-temperature method, particularly at room temperature. Therefore, the emulsion has the advantage that it is non-irritating and has a low possibility of causing allergies, particularly skin allergies, if any. The emulsion can also be in the form of many cosmetics, such as creams, milks, serums, and lotions.

[0017] The main advantage of the emulsions encompassed by the present application is that they have a Brookfield viscosity that can be adjusted in a wide range from 10 mPa.s to 3,000 mPa.s, thus offering a wide palette of target sensory properties. In fact, the O / W emulsions according to the present application may be sprayable or fluid. The emulsions therefore have a good emollient effect on the skin as well as a good moisturizing effect on the upper layers of the epidermis.

[0018] According to one embodiment, the emulsion comprising cyclodextrin and modified starch has a Brookfield viscosity of less than 3,000 mPa.s, preferably less than or equal to 2,800 mPa.s, preferably less than or equal to 2,600 mPa.s, and can even reach values ​​below 10 mPa.s, while being stable in the absence of an aqueous phase thickener.

[0019] Another advantage of emulsions is that they can be used for a wide spectrum of cosmetic or dermatological purposes, i.e., they can be versatile in terms of the envisaged end product. In this respect, emulsions according to the present application can be fluid gels, lotions, creams, milks, etc. Furthermore, emulsions are advantageously non-irritating and non-allergenic to the skin.

[0020] Another advantage is that the emulsions can be prepared by a method characterized by a very simple implementation with minimal energy input, in particular by introducing all components into a single tank or reactor ("one-pot" formulation). From the implementation point of view, this method is advantageously a "low-temperature method", unlike many conventional solid or paste emulsifiers, such as waxes, which require elevated temperatures for their implementation above 60°C, or even above 80°C (the components must be melted and can be used at "high temperatures"). The concept of low-temperature method includes emulsification methods in which the only heat input is due to the dissipation of energy caused by mechanical stirring. "Low-temperature method" should be understood to mean that the emulsions can be prepared at temperatures below 45°C, or below 35°C, or even better, at room temperature. DETAILED DESCRIPTION OF THE INVENTION

[0021] The objective of the present application is a cosmetic or dermatological emulsion of medium to fluid viscosity, or even a very fluid viscosity that may then be sprayable. The emulsifier of the emulsion consists mainly, or even exclusively, of plant-derived ingredients selected from cyclodextrin and starch-based emulsifiers and / or starch-derived emulsifiers. The emulsion is made possible by the combination of cyclodextrin and starch-based emulsifiers and / or starch-derived emulsifiers, which may make it possible to avoid adding additional emulsifying surfactants, such as petrochemical-derived emulsifiers, or emulsifying co-surfactants of petrochemical or natural origin. The emulsion according to the objective of the present application has the advantage that it can advantageously contain reduced amounts of petrochemical-derived emulsifiers with low molecular weights, or can be completely free of such emulsifiers.

[0022] The applicant has found that oil-in-water emulsions formed by combining cyclodextrin with a starch-based emulsifier and / or a starch-derived emulsifier, such as octenyl succinate starch, advantageously have a Brookfield viscosity of less than 3,000 mPa.s at 20°C and 20 rpm for 1 minute and are stable. At a viscosity of 3,000 mPa.s, the emulsion has the consistency of a gel. By adjusting the amount of cyclodextrin and starch-derived emulsifier, it is possible to advantageously change the viscosity of the emulsion formed to less than 1,000 mPa.s or less than 100 mPa.s, i.e., fluid enough to be applied by spraying, or even to less than 10, i.e., very fluid. Thus, the emulsion can have a variety of textures.

[0023] The emulsions according to the present application may consist of spherical or ellipsoidal droplets having a size of less than 30 μm, or even less than 10 μm. The adjustable viscosity combined with a droplet size of less than 30 μm, or even less than 10 μm, advantageously allows a wide variety of textures to be obtained, from creams to milks to lotions.

[0024] emulsion An emulsion is a dispersion of a liquid (or a substance rendered liquid) as fine droplets in another liquid that is immiscible with the first liquid. Emulsions have a macroscopic homogeneous appearance but appear heterogeneous under a microscope. The droplet-like liquid is called the dispersed (or discontinuous) phase, while the other liquid is called the dispersed (or continuous) phase. In general terms, an emulsion consists of an aqueous phase, an oil phase, and two phases (in the case of a simple emulsion): a hydrophilic (aqueous) phase and a lipophilic (fatty) phase. The most commonly encountered emulsions are those containing a lipophilic phase dispersed in a continuous aqueous phase, and are called oil-in-water (O / W) emulsions, as opposed to water-in-oil (W / O) emulsions.

[0025] The object of the present application is to provide an oil-in-water emulsion, an oil phase dispersed in an aqueous phase; an emulsifier system consisting of at least one cyclodextrin and at least one starch-based emulsifier and / or starch-derived emulsifier, the emulsion has a Brookfield viscosity of less than 3,000 mPa.s, preferably 2,800 mPa.s or less, preferably 2,600 mPa.s or less, at 20 rpm using an SP5 spindle at 20°C for 1 minute; The starch-based emulsifier and / or starch-derived emulsifier is an oil-in-water emulsion having a solubility in water at 22°C according to Test A of 50% or more, or 75% or more, or 85% or more, or 95% or more, or 98% or more, or 99% or more, or 100%.

[0026] Preferably, the oil-in-water emulsion comprises at least one cyclodextrin in a mass content ranging from 2.5 to 6% by weight, 3 to 5% by weight, most preferably 3.5 to 4.5% by weight, or 2.5 to 4% by weight of the emulsion, relative to the total weight of the emulsion.

[0027] Preferably, the oil-in-water emulsion comprises at least one starch-based and / or starch-derived emulsifier in a mass content in the range of 1-7%, 1.5-6%, 2-5%, most preferably 2.5-4.5% or 1.0-2.5% by weight of the emulsion, relative to the total weight of the emulsion.

[0028] Preferably, the oil-in-water emulsion contains native or modified granular starch, preferably modified amphiphilic granular starch, more preferably octenyl succinate granular starch, in an amount equal to or less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.5% by weight and most preferably equal to 0% by weight, relative to the total weight of the emulsion.

[0029] Preferably, the emulsifier system is the only emulsifier present in the emulsion.

[0030] Cyclodextrin In this application, the term "cyclodextrin" refers to and includes any one of the other known cyclodextrins, such as natural and unsubstituted cyclodextrins containing 6 to 12 glucose units joined by a covalent bond between carbons 1 and 4, particularly α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin, which contain 6, 7, and 8 glucose units, respectively.

[0031] The term also includes "cyclodextrin derivatives," i.e., molecules in which at least some of the OH-hydroxyl groups have been converted to OR groups, where R generally represents an alkyl group. In this respect, cyclodextrin derivatives include, in particular, methylated or ethylated cyclodextrins, but also those substituted with hydroxyalkyl groups, such as hydroxypropylated and hydroxyethylated cyclodextrins.

[0032] Preferred cyclodextrins according to the invention are α-cyclodextrin, β-cyclodextrin and γ-cyclodextrin, with natural β-cyclodextrin being most preferred. The cyclodextrin may in particular be in the form of a crystalline, semi-crystalline or amorphous powder. Examples of cyclodextrins useful in the emulsions encompassed by the present application are those sold by the applicant under the references "Beaute by Roquette® CD 102" or "Beaute by Roquette® Roquette® CD 100".

[0033] Among the cyclodextrins useful in the present invention, those having a volume average diameter and a size distribution of 5 to 300 microns, preferably 10 to 250 microns, and more preferably 10 to 100 microns, can be selected. Furthermore, among the cyclodextrins useful in the present invention, those having a water content ranging from 0.5 to 20% by weight of the crude cyclodextrin, preferably 1 to 15%, and more preferably 3 to 13% can be selected. Finally, cyclodextrins can be selected by combining the above characteristics of size distribution and water content.

[0034] Without being bound by any theory, the Applicant believes that the cyclodextrins of the emulsifier systems useful in the oil-in-water emulsions according to the present application make it possible to obtain stable emulsions, i.e., they confer stability to these emulsions for at least 24 hours, or at least 48 hours, or at least 1 week, or at least 1 month, or at least 6 months, or at least 12 months, or at least 24 months. "Stable" should be understood to mean the absence of creaming or marbling visible to the naked eye.

[0035] According to one embodiment, the mass content of cyclodextrin relative to the total weight of the emulsion ranges from 2.5 to 6%, 3 to 5%, most preferably 3.5 to 4.5%, or 2.5 to 4% by weight of the emulsion.

[0036] Starch-based emulsifiers or emulsifiers derived from starch "Starch-based emulsifier" should be understood to mean a starch having emulsifying properties, in particular the ability to emulsify oil in water. Thus, the starch-based emulsifier useful in the present invention is a starch modified by hydrophobic functionalization, or amphiphilic functionalization, or a combination of these functionalizations. The starch subjected to at least one of the functionalizations can be a native starch or, better still, a starch modified by heat or enzymes, which can be a pregelatinized, gelatinized, spray-dried, or hydrolyzed starch.

[0037] According to one embodiment, the starch subjected to at least one of the functionalizations is a native starch. According to another preferred embodiment, the starch subjected to at least one of the functionalizations is a pregelatinized starch. According to another preferred embodiment, the starch subjected to at least one of the functionalizations is a hydrolyzed starch.

[0038] "Starch-derived emulsifier" should be understood to mean a dextrin, or hydrolyzed starch, or maltodextrin, capable of emulsifying oil in water. The starch-derived emulsifier may be a dextrin, or hydrolyzed starch, or maltodextrin, which has been subjected to hydrophobic or amphiphilic functionalization, or a combination of these functionalizations.

[0039] The term "hydrophobic and / or amphiphilic functionalization" refers to a chemical reaction between a hydrophobic and / or amphiphilic reagent and some or all of the hydroxyl groups of starch or starch-derived substances. This reaction is generally a "substitution" or "grafting" by forming covalent bonds of the ester, ether, or amide type.

[0040] According to the "amphiphilic" embodiment, the starch-based emulsifiers, or emulsifiers derived from starch, are obtained by esterification of the hydroxyl groups by reaction with acyl chlorides (RC(=O)Cl), or alcohol esters (RC(=O)OR') or acid anhydrides (RC(=O))O) or (RC(=O)OC(=O)R').

[0041] The acyl chloride may be a chloride obtained from one of the following carboxylic acids (RC(=O)OH), where R is a saturated or unsaturated aliphatic group, having from 2 to 24 carbons, preferably from 4 to 24 carbons, more preferably propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, pelargonic acid, octanoic acid, decanoic acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid, anhydrides of these acids, mixed anhydrides of these acids, and any mixture of these products.

[0042] The alcohol may be a linear, branched, or cyclic alcohol composed of a carbon skeleton having at least two carbon atoms. The alcohol may contain at least one unsaturated bond, i.e., at least one carbon-carbon double bond. The alcohol may be a linear, branched, or cyclic aliphatic alcohol composed of a carbon skeleton having 8 to 36 carbon atoms. The fatty alcohol may contain at least one unsaturated bond. Examples of unsaturated fatty alcohols are octanol, nonanol, decanol, undecanol, dodecanol, tetradecanol, hexadecanol, octadecanol, docosanol, and policosanol.

[0043] The acid anhydride may be the anhydride of one of the polycarboxylic acids described below.

[0044] The polycarboxylic acid may be a linear, branched, or cyclic polycarboxylic acid consisting of a carbon skeleton having at least two carbon atoms. Polycarboxylic acids, such as maleic acid, glutathionic acid, and fumaric acid, may contain at least one unsaturated bond, i.e., at least one carbon-carbon double bond. The polycarboxylic acid may also contain at least one alcohol group attached to the carbon chain. The polycarboxylic acid may contain at least two carboxylic acid groups. According to one embodiment, the polycarboxylic acid is a linear dicarboxylic acid having an acid group at the end of the carbon chain. Examples of linear dicarboxylic acids are ethanedioic acid (i.e., oxalic acid), propanoic acid, butanedioic acid (i.e., succinic acid), dihydroxybutanedioic acid (i.e., tartaric acid), 2-hydroxybutanedioic acid (i.e., malic acid), pentanedioic acid (i.e., glutaric acid), hexanedioic acid (i.e., adipic acid), tetrahydroxyhexanedioic acid (i.e., sugar acid), gluconic acid, heptanoic acid (i.e., pimelic acid), octanedioic acid, nonanedioic acid, and decanedioic acid (i.e., sebacic acid).

[0045] According to one embodiment, the acid anhydride is a linear dicarboxylic acid anhydride. According to one embodiment, the acid anhydride is succinic anhydride.

[0046] According to one embodiment, the acid anhydride is a succinic anhydride, in particular substituted with a saturated or unsaturated alkyl chain, such as octenylsuccinic anhydride or dodecylsuccinic anhydride.

[0047] The level of functionalization can affect the solubility of the functionalized starch. If the solubility is insufficient, a pregelatinization treatment can be applied to the functionalized starch to make it sufficiently soluble.

[0048] The starch may be a tuber, legume, or cereal starch, or a mixture of at least two of these starches. For example, the starch may be wheat, corn, potato, pea, bean, or rice starch, or a mixture of at least two of these starches. Dextrins, hydrolyzed starches, and maltodextrins can be derived from one of these starches. These starches may also be amylopectin-rich starches. Preferably, the starch is not millet starch. More preferably, the starch is selected from starches containing at least 90% by weight, preferably at least 95%, preferably at least 98%, and most preferably at least 99% amylopectin by weight of the starch. Even more preferably, the starch is amylopectin-rich corn starch, and the starch is most preferably waxy corn starch, i.e., a starch whose polymer chains contain at least 99% by weight amylopectin.

[0049] According to one embodiment, the emulsifying starch is a waxy starch functionalized with an alkenyl succinate group, in particular octenyl succinate or dodecyl succinate. Examples of starches with octenyl succinate functional groups are Cleargum® CO 01 and CO 03, sold by Roquette. These starches are hydrolyzed starches and are known to be water-soluble, i.e., soluble in water, making it possible to prepare conventional emulsions.

[0050] According to one embodiment, the octenyl succinate starch useful in the emulsions and methods encompassed by the present application is in the form of a sodium, calcium, or aluminum salt, preferably in the form of a sodium or calcium salt, and more preferably in the form of a sodium salt.

[0051] According to another embodiment, the starchy emulsifier is an octenyl succinate-functionalized dextrin, such as Cleargum® CO A1 sold by Roquette, which is also known to be water-soluble and allows the preparation of conventional emulsions.

[0052] According to the "hydrophobic" embodiment, the emulsifying starch, or starch-derived emulsifier, is obtained simply by grafting hydrophobic groups by radical reaction, as disclosed, for example, in the applicant's EP-A-3 180 372.

[0053] According to one embodiment, the starch-derived emulsifier has a weight average molecular weight in the range of 10 to 2,000 kDa, or 20 to 1,500 kDa, or 30 to 1,000 kDa, or 40 to 800 kDa, or 45 to 700 kDa, as measured by HPSEC-MALLS.

[0054] The weight average molecular weight Mw is determined by one skilled in the art using HPSEC-MALLS (High Performance Size Exclusion Chromatography coupled online with Multiple Angle Laser Light Scattering) size exclusion chromatography. This quantity can be measured by size exclusion chromatography according to the following protocol: - preparing a sample of starch-derived emulsifier by solubilizing the sample in a dilution solvent consisting of a DMSO / NaNO3 mixture (0.1 M NaNO3 in DMSO) by heating the sample at 100°C for 30 minutes, said sample having a concentration ranging from 2 to 10 mg of starch-derived emulsifier sample per mL of dilution solvent; - using a high-performance liquid chromatograph (HPLC) equipped with a pump operating in isocratic mode and circulating the elution solvent at 0.3 mL / min, a refractometer, an 18-angle multi-angle light scattering laser detector, e.g., a Wyatt DAWN DSP detector, heated to 35°C, and a thermostatic oven for the column, heated to 35°C, and equipped with, for example, a SUPREMA polyhydroxymethacrylate column, the elution solvent being, for example, 0.1 M aqueous sodium nitrate containing 0.02 wt% sodium azide; - Injecting a sample volume of about 100 μL into the device.

[0055] The weight average molecular weight and number average molecular weight can be determined from the resulting spectra by reprocessing the spectra with a first order exponential function using, for example, ASTRA v.4 analysis software.

[0056] According to one embodiment, the starch-based emulsifier and starch-derived emulsifier have a water solubility of 50% or more, or 75% or more, or 85% or more, or 95% or more, or 98% or more, or 99% or more, or 100% at 22°C according to Test A. Starch-based emulsifiers having water solubilities in these ranges include modified pregelatinized and amphiphilic starches, modified spray-dried and amphiphilic starches, modified acid-hydrolyzed and amphiphilic starches, and modified enzyme-hydrolyzed and amphiphilic starches. The starch-based emulsifier or starch-derived emulsifier can be selected from octenyl succinate pregelatinized starch, octenyl succinate gelatinized starch, octenyl succinate hydrolyzed starch, octenyl succinate hydrolyzed and pregelatinized starch, and mixtures thereof.

[0057] According to one embodiment, the emulsifier system contains native or modified granular starch, preferably modified amphiphilic granular starch, more preferably octenyl succinate granular starch, in an amount equal to or less than 5% by weight, preferably less than 2% by weight, more preferably less than 1% by weight, even more preferably less than 0.5% by weight and most preferably equal to 0% by weight, relative to the weight of the starch-based or starch-derived emulsifier.

[0058] Without being bound by any theory, the Applicant has in particular a solubility in water at 22° C. according to Test A of at least 50%, preferably greater than or equal to 98%, preferably greater than or equal to 99% and more preferably equal to 100%, and optionally has the following characteristics: -Selection of the mass content of cyclodextrin in the emulsion in the range of 2.5 to 4% by weight of the emulsion. - selection of a mass content of starch-based emulsifier or starch-derived emulsifier in the range of 1.0 to 2.5% by weight of the emulsion; It is believed that the use of a water-soluble starch-based or starch-derived emulsifier in combination with at least one of the following makes it possible to prepare oil-in-water emulsions having a medium viscosity, i.e., 3,000 mPa.s or less, to a low viscosity, i.e., 1,000 mPa.s or less, or even a very low viscosity, i.e., 100 mPa.s or less.

[0059] When the starch-based emulsifier is a starch and has a solubility equal to 100% according to Test A, starch granules, i.e., solid starch particles, are substantially invisible in the aqueous phase under an optical microscope because all starch granules have been decomposed and converted into anhydroglucose polymer chains solubilized in the aqueous phase. Modified amphiphilic and pregelatinized, spray-dried, acid-hydrolyzed, or enzyme-hydrolyzed starches are in fact sufficiently soluble in water to be solubilized without steam cooking. Dispersing them in water in a stirred vessel, optionally with heating, for example, using a double envelope or a plunge coil, allows them to be completely dissolved in water, preferably at temperatures ranging from 10°C to 60°C, or from 15°C to 60°C, or from 20°C to 60°C, or from 20°C to 50°C, or from 20°C to 40°C. On the other hand, regular granular starches, as well as modified amphiphilic granular starches, especially those that have not been pregelatinized or spray-dried or acid- or enzymatically hydrolyzed, must be heated to temperatures of 60° C. to 150° C., often 70-80° C. to 120° C. In most cases, this is achieved by steam "cooking" at 100-150° C. and 1-5 bar, which requires special equipment such as a steam nozzle and a specific stirring tank to agitate the viscous starch gel obtained by steam cooking.

[0060] Examples of water-soluble pregelatinized starches with octenyl succinate functional groups are sold by Roquette as Cleargum® CO 01 and CO 03. These octenyl succinate starches have a solubility in water close to or even equal to 100% at 22°C according to Test A.

[0061] The solubility is measured according to Test A, which consists of the following method: - taking a test portion mass of about 5.0 g (m test portion) from a sample of the starch-derived emulsifier, said mass being expressed as a dry mass; - dispersing this mass in 200 ml of water in Erlenmeyer at 22° C., then placing it in a water bath at 22° C. under magnetic stirring for 4 hours, stirring every 30 minutes for 5 minutes, - filtering the contents of the bottle through a filter having a pore size of 8 μm for a Whattamn 2 V filter; - pipetting 50 mL of the filtrate and introducing this amount into a dry, tared crystallizer; - evaporating the water from the crystallizer by heating the water to 60°C for 45 minutes and then to 130°C for 90 minutes; - weighing the mass of starch-derived emulsifier obtained after drying (m dry extract) after cooling in a desiccator.

[0062] The solubility is calculated in the following way: Solubility = [m dry extract × 200 × 100] / [50 × m test portion]

[0063] The dry mass of the test portion is calculated according to ISO standard 1666:1996.

[0064] According to one embodiment, the starch-based emulsifier or starch-derived emulsifier has a degree of hydrophobic and / or amphiphilic group substitution ranging from 0.001 to 3, or from 0.01 to 2.8, or from 0.015 to 2.6. According to another embodiment, the degree of hydrophobic and / or amphiphilic group substitution ranges from 0.001 to 0.1, or from 0.01 to 0.10, or from 0.015 to 0.05. For example, for a starch-based emulsifier or a starch-derived emulsifier functionalized with octenyl succinate groups, the degree of substitution may be estimated from the amount of octenyl succinate groups attached to the emulsifier, as determined by gas chromatography using internal calibration on a methyl-derivatized sample. The chromatography column is a DB1 capillary column from J&W Scientific or equivalent. Derivatization with methyl is carried out by transesterification with methanolic hydrochloric acid, followed by extraction with chloroform. The internal standard measurement is methyl laurate. The amount of octenyl succinate groups attached to the starch-based or starch-derived emulsifier is then expressed as a weight percent of the total sample mass of emulsifier.

[0065] According to one embodiment, the mass content of the starch-based or starch-derived emulsifier relative to the total weight of the emulsion is in the range of 1-7%, 1.5-6%, 2-5%, most preferably 2.5-4.5%, or 1.0-2.5% by weight of the emulsion.

[0066] Petrochemical-derived emulsifying co-surfactants "Petrochemical-derived emulsifying co-surfactant" refers to a petrochemical-derived emulsifying surfactant that is added to an emulsion in addition to an emulsifier system consisting of a cyclodextrin and a starch-derived emulsifier already present, in a smaller amount than would be required if the petrochemical-derived emulsifying surfactant were the only emulsifier present in the emulsion. "Petrochemical-derived emulsifying surfactant" should be understood to mean any molecule or polymer derived solely from petrochemical-derived raw materials.

[0067] Petrochemically derived emulsifying surfactants include glycol derivatives, particularly ethoxylated and polyethoxylated glycol derivatives.

[0068] Naturally derived O / W emulsifying co-surfactant In the present application, the term "naturally derived O / W emulsifying co-surfactant" refers to a naturally derived oil-in-water emulsifying surfactant that is added to an emulsion in addition to an emulsifier system consisting of a cyclodextrin and a starch-based emulsifier or a starch-derived emulsifier already present, in a smaller amount than would be required if the emulsifying surfactant were the only emulsifier present in the emulsion. The term "naturally derived oil-in-water O / W emulsifying surfactant" refers to any molecule that originates from renewable resources, in particular is extracted from or secreted by plants, microorganisms or algae, and that is capable of obtaining or promoting the stability of an oil-in-water O / W emulsion after physical, chemical or enzymatic modification.

[0069] This naturally occurring O / W emulsifying co-surfactant may also be chosen from products that are naturally biodegradable in natural hydration media, in particular products with a hydrophilic-lipophilic balance (HLB) of 8 to 20, preferably 9 to 16 and better still 11 to 14.

[0070] By way of example, this naturally occurring O / W emulsifying cosurfactant may be selected from the following products, provided that it satisfies the above HLB conditions: alkyl polyglucosides; mixtures of at least one alkyl polyglucoside and at least one fatty alcohol; non-ethoxylated polyol fatty acid esters, in particular non-ethoxylated fatty acid esters of glycerol, polyglycerol, sorbitol, sorbitan, anhydrohexitols, such as, in particular, isosorbide, mannitol, xylitol, erythritol, maltitol, sucrose, glucose, polydextrose, hydrogenated glucose syrup, dextrin, and hydrolyzed starch.

[0071] The naturally occurring O / W emulsifying cosurfactant is preferably selected so as to be naturally biodegradable in a hydrated natural environment. In particular, it may be a non-ethoxylated polyol fatty acid ester obtained by transesterification from a fatty acid or from an oil or oil mixture. The fatty acids used have 8 to 22 carbon atoms, preferably 10 to 18 carbon atoms, and especially 12 to 18 carbon atoms. These acids may be linear or branched, saturated or unsaturated, and may have one or more lateral hydroxyl functional groups. The oil may be liquid to solid at room temperature, saturated or unsaturated, and optionally have hydroxyl functional groups, preferably an iodine value of 1 to 145, especially 5 to 105.

[0072] The naturally occurring O / W emulsifying cosurfactant can in particular be chosen from polyglycerol esters, preferably from esters resulting from the reaction of a polyglycerol containing 2 to 12 glycerol units, preferably 3 to 10 glycerol units, with at least one partially hydrogenated or non-hydrogenated vegetable oil having an iodine number of 1 to 15, in particular 5 to 10. These can in particular be esters of polyglycerol with oleic acid, stearic acid, palmitic acid, lauric acid, diisostearic acid and caprylic acid, in particular the following products:Polyglyceryl-5 dioleate with an HLB of about 8 (e.g., Dermofeel® G 5 DO from Evonik Dr. Straetmans GmbH), polyglyceryl-2 caprate with an HLB of about 9 (e.g., HYDRIOL® PGC.2 from HYDRIOR), polyglyceryl-3 stearate with an HLB of about 9 (e.g., Dermofeel® PS from Evonik Dr. Straetmans GmbH), polyglyceryl-2 laurate with an HLB of about 9 (e.g., Dermofeel® G2L from Evonik Dr. Straetmans GmbH), polyglyceryl-3 palmitate with an HLB of about 10 (e.g., Dermofeel® PP from Evonik Dr. Straetmans GmbH), polyglyceryl-10 diisostearate with an HLB of about 11 (e.g., Dermofeel® PP from Evonik Dr. Straetmans GmbH), polyglyceryl-3 stearate with an HLB of about 9 (e.g., Dermofeel® PP from Evonik Dr. Straetmans GmbH), polyglyceryl-3 palmitate with an HLB of about 10 (e.g., Dermofeel® PP from Evonik Dr. Straetmans GmbH), polyglyceryl-10 diisostearate with an HLB of about 11 (e.g., Dermofeel® PS from Evonik Dr. Straetmans GmbH), polyglyceryl-2 caprate with an HLB of about 9 (e.g., Dermofeel® PGC.2 from Evonik Dr. Straetmans GmbH), polyglyceryl-3 stearate with an HLB of about 9 (e.g., Dermofeel® G2L from Evonik Dr. Straetmans GmbH), polyglyceryl-3 palmitate with an HLB of about 10 (e.g., Der Dermofeel® G10 DI from Dr. Straetmans GmbH), polyglyceryl-6 caprylate with an HLB of about 11.5, polyglyceryl-5 laurate with an HLB of about 13 (e.g. Dermofeel® G5L from Evonik Dr. Straetmans GmbH), polyglyceryl-3 caprate with an HLB of about 14 (e.g. HYDRIOL® PGC.3 from HYDRIOR), polyglyceryl-4 caprate with an HLB of about 14 (e.g. MASSOCARE PG4 C from Masso), polyglyceryl-10 monolaurate with an HLB of about 14.8, polyglyceryl-6 caprylate with an HLB of about 15 (e.g. Dermofeel® G 6 CY from Dr. Straetmans GmbH / Evonik), polyglyceryl-10 laurate with an HLB of about 16 (e.g. Dr. Straetmans Dermofeel® G 10 L from GmbH / Evonik).

[0073] The naturally occurring O / W emulsifying co-surfactant may preferably be selected from alkyl polyglucosides, sometimes also called alkyl polyglycosides and designated by the acronym APG. These emulsifiers are essentially well-known nonionic surfactants. French Patent No. 2 948 285 presents them from the structural point of view and describes how to prepare them. They can be represented by the following general formula (I): R1-O-(R2-O)p-(S)n During the ceremony, -S represents a reducing sugar, which may contain 5 to 6 carbon atoms; -R1 represents a linear or branched alkyl and / or alkenyl group containing from about 8 to 24 carbon atoms, or an alkylphenyl group in which the linear or branched alkyl group contains from about 8 to 24 carbon atoms; -R2 represents an alkylene group containing 2 to 4 carbon atoms; -n represents a value in the range of 1 to 15, -p represents a value in the range of 0 to 10.

[0074] In formula (I), reducing sugar refers to a sugar derivative whose structure does not have a glycosidic bond established between the anomeric carbon and the oxygen of the acetal group, as defined in the reference book: "Biochemistry", Daniel Voet / Judith G. Voet, p. 250, John Wyley & Sons, 1990. The oligomeric structure (S)n can be provided in any form of isomer, such as optical, geometric or positional isomer, or can represent a mixture of isomers.

[0075] According to one particular aspect of the invention, in the definition of the compound of formula (I), S represents a reducing sugar selected from glucose, dextrose, sucrose, fructose, idose, gulose, galactose, maltose, isomaltose, maltotriose, lactose, cellobiose, mannose, ribose, xylose, arabinose, lyxose, allose, altrose, dextran or talose, more particularly a reducing sugar selected from glucose, xylose or arabinose.

[0076] A first preferred alternative of alkyl polyglucosides according to the invention are C12-C20 alkyl glucosides, i.e. compounds of formula (I), wherein -R1 more specifically represents a linear or branched alkyl and / or alkenyl group containing about 12 to 20 carbon atoms; -p is a value in the range of 0 to 3, preferably zero; -S represents glucose, fructose, or galactose, and more preferably glucose.

[0077] A second preferred alternative for alkyl polyglucosides according to the present invention is the C12-C20 alkyl glucosides of the first preferred alternative, wherein -R1 more specifically represents a straight chain alkyl group containing about 12 to 20 carbon atoms; -p is equal to zero, -S represents glucose.

[0078] Alkyl polyglucosides of formula (I) are commercially available, in particular, under the following names: Plantacare® 810 UP (R1 is C8-C10 / INCI: caprylyl / capryl glucoside), Plantacare® 818 UP (R1 is C8-C16 / INCI: coconut oil alkyl glucoside), Plantacare® 2000 UP (R1 is C8-C16 / INCI: decyl glucoside) and Plantacare® 1200 UP (R1 is C12-C16 / INCI: lauryl glucoside), available from BASF; Macanol® 810 available from FCI Technology. (R1 is C8-C10), Macanol® 1200 (R1 is C12-C14), Macanol® 816 (R1 is a mixture of C8, C10, C12, C14, and C16); Neocare MF 0718 (R1 is C8-C10 / INCI: caprylyl / capryl glucoside), Neocare MF 0012 (R1 is C12-C14 / INCI: lauryl glucoside), Neocare MF 0002 (R1 is C8-C16 / INCI: decyl glucoside), Neocare MF 818 (R1 is C8-C16 / INCI: coconut oil alkyl glucoside), available from Neochem; Tego Care CG (R1 is C8-C16 / INCI: coconut oil alkyl glucoside), available from Evonik Healthcare. 90 (R1 is C14~C16 / INCI: Cetearyl glucoside).

[0079] The naturally occurring O / W emulsifying co-surfactant may be a mixture of at least one alkyl polyglucoside and at least one fatty alcohol. In these mixtures, the alkyl polyglucoside may be selected from any of the alkyl polyglucosides useful in the present invention described above. Fatty alcohols useful for mixing with the alkyl polyglucosides include linear or branched chain fatty alcohols having a total number of carbon atoms ranging from 8 to 24.

[0080] Commercially available mixtures of alkyl polyglucosides and fatty alcohols useful in the present invention are those sold by the company SEPPIC: Montanov® 14 (INCI: myristyl alcohol and myristyl glucoside), Montanov® 202 (INCI: arachidyl alcohol and behenyl alcohol and arachidyl glucoside), Montanov® 68 (INCI: cetearyl alcohol and cetearyl glucoside), Montanov® 82 (INCI: cetearyl alcohol and coco-glucoside), Montanov® S (INCI: coco-glucoside and coconut alcohol), Montanov® L (INCI: C14-22 alcohol and C12-20 alkyl glucoside).

[0081] Pickering Emulsion The emulsion according to the present application may also be a Pickering emulsion.

[0082] Pickering emulsions are stabilized by colloidal particles, usually silica, talc, or insoluble granular starch, present at the interface between the continuous and dispersed phases. In the context of the present invention, these colloidal particles are organic particles formed by in-situ precipitation from an inclusion complex between at least one cyclodextrin and at least one fatty molecule present in the emulsion and derived from the oil that constitutes the emulsion. These particles are highly compatible with skin and hair and do not damage animal cell membranes. Without being bound by any theory, it is possible that starch-derived emulsifiers help form or stabilize the Pickering emulsions formed in this way.

[0083] Mixed emulsion The emulsions according to the invention may also be mixed emulsions, i.e., stabilized simultaneously and jointly by amphiphilic molecules, as in conventional emulsions, and by organic particles formed by in situ precipitation of inclusion complexes between at least one cyclodextrin and at least one fatty molecule present in the emulsion.

[0084] Oil phase The oil phase comprises: at least one oil chosen from non-volatile or volatile oils, and / or at least one wax chosen from polar hydrocarbon waxes, ester waxes, alcohol waxes, non-polar hydrocarbon waxes or silicone waxes.

[0085] oil "Oil" is understood to mean any fatty substance in liquid form at room temperature (25°C) and atmospheric pressure (1,013,105 Pa).

[0086] non-volatile oil As mentioned above, the oil-in-water emulsion according to the present invention comprises at least one non-volatile oil, more specifically, the non-volatile oil is selected from polar or non-polar non-volatile hydrocarbon oils and mixtures thereof, preferably from polar non-volatile oils, and in particular from C10-C26 alcohols, ester oils, and vegetable oils, either alone or in mixtures.

[0087] "Hydrocarbon oil" is understood to mean an oil that is essentially formed by or further consists of carbon and hydrogen atoms, and optionally oxygen atoms, nitrogen atoms, and does not contain silicon atoms or fluorine atoms.Therefore, hydrocarbon oil is different from silicone oil and fluorinated oil.Within the meaning of the present invention, "silicone oil" is understood to mean an oil that contains at least one silicon atom, in particular at least one Si-O group.Non-volatile refers to an oil that has a vapor pressure (measured according to OECD Standard 104 dated 07 / 27 / 95) of less than 2.66 Pa, preferably less than 0.13 Pa.

[0088] Polar non-volatile hydrocarbon oil Preferably, the oil-in-water emulsion according to the present invention comprises at least one polar nonvolatile hydrocarbon oil. This hydrocarbon oil may contain alcohol, ester, ether, carboxylic acid, amine and / or amide groups. Preferably, the hydrocarbon oil does not contain heteroatoms such as nitrogen, sulfur, and phosphorus. In this case, the polar nonvolatile hydrocarbon oil comprises at least one oxygen atom. In particular, this polar nonvolatile hydrocarbon oil comprises at least one alcohol functional group (which in this case becomes an "alcohol oil") or at least one ester functional group (which in this case becomes an "ester oil"). The ester oil that can be used in the oil-in-water emulsion according to the present invention can in particular be hydroxylated. Thus, the oil-in-water emulsion can comprise at least one polar nonvolatile hydrocarbon oil, in particular (1) Polar nonvolatile hydrocarbon oils selected from C10-C26 alcohols, preferably monoalcohols. The C10-C26 alcohols may be saturated or unsaturated, branched or unbranched, and contain 10 to 26 carbon atoms, preferably 14 to 24 carbon atoms. Examples of fatty alcohols that can be used according to the invention include linear or branched fatty alcohols of synthetic or even natural origin, such as alcohols derived from plant (copra, palm kernel, palm, etc.) or animal (tallow, etc.) materials. Naturally, other long-chain alcohols can also be used, such as ether alcohols or alcohols also known as Guerbet alcohols. Finally, longer or shorter fragments of some naturally occurring alcohols can be used, such as coco (C12-C16) or tallow (C16-C18) or diol or cholesterol-type compounds. As particular examples of fatty alcohols preferably used, mention may in particular be made of lauryl, isostearyl, oleyl alcohol, 2-butyloctanol, 2-undecylpentadecanol, 2-hexyldecyl alcohol, isocetyl alcohol, octyldodecanol, and mixtures thereof. According to an advantageous embodiment of the invention, the alcohol is chosen from among octyldodecanol. (2) Optionally hydroxylated monoesters, diesters, triesters of C2-C8 mono- or polycarboxylic acids with C2-C8 alcohols, in particular: (2.1) optionally hydroxylated monoesters of C2-C8 carboxylic acids and C2-C8 alcohols; (2.2) optionally hydroxylated diesters of C2-C8 dicarboxylic acids with C2-C8 alcohols, such as diisopropyl adipate, diethyl-2-hexyl adipate, dibutyl adipate, 2-diethyl-hexyl succinate, (2.3) Optionally hydroxylated triesters of C2-C8 tricarboxylic acids with C2-C8 alcohols, for example citrate esters such as trioctyl citrate, triethyl citrate, acetyltributyl citrate, tributyl citrate, etc. (3) Esters of C2-C8 polyols with one or more C2-C8 carboxylic acids, for example, diesters of glycols with monoacids such as neopentyl glycol diheptanoate, or triesters of glycols with monoacids such as triacetin. (4) Ester oils, especially those having 17 to 70 carbon atoms: examples include monoesters, diesters, and triesters. The ester oils may be hydroxylated or non-hydroxylated. Nonvolatile ester oils include, for example: (4.1) Monoesters having a total of 17 to 40 carbon atoms, in particular monoesters of the formula R1-COO-R2, where R1 is a residue of a linear, branched or aromatic fatty acid containing 4 to 40 saturated or unsaturated carbon atoms, and R2 is in particular a branched hydrocarbon chain containing 3 to 40 carbon atoms, with the proviso that R1+R2 is 17 or more, such as, for example, Purcellin (ketoaryl octanoate) oil, isononyl isononanoate, C12-C15 alcohol benzoate, ethyl 2-hexyl palmitate, octyldodecyl They may be selected from among octyl pentanoate, octyl-2-dodecyl stearate, octyl-2-dodecyl erucate, isostearyl isostearate, octyl-2-dodecyl benzoate, octanoates, decanoates or ricinoleates of alcohols or polyalcohols, isopropyl myristate, isopropyl palmitate, butyl stearate, hexyl laurate, 2-ethylhexyl palmitate, 2-hexyl-decyl laurate, 2-octyldecyl palmitate, 2-octyldodecyl myristate, etc. Preferably, they are esters of the formula R1-COO-R2, where R1 represents a residue of a linear or branched fatty acid having from 4 to 40 carbon atoms, R2 represents, in particular, a branched hydrocarbon chain containing from 3 to 40 carbon atoms, and R1 and R2 are 10 so that R1+R2 is 17 or more. Even more particularly, the esters contain a total of 17 to 40 carbon atoms. Preferred monoesters include isononyl isononanoate, isopropyl palmitate, oleyl erucate and / or octyl-2-dodecenyl neopentanoate. (4.2) Fatty acid monoesters, especially those having 18 to 22 carbon atoms, in particular oleic acid, lauric acid, stearic acid, and diols, such as propylene glycol monostearate. (4.3) Diesters, in particular those containing a total of 18 to 60 carbon atoms, in particular those containing a total of 18 to 50 carbon atoms. In particular, the following can be used: diesters of dicarboxylic acids and monoalcohols, preferably, for example, diisostearyl malate, or diesters of monocarboxylic acids and dialcohols, such as, for example, the 1,3-propanediyl ester of octanoic acid (i.e., propanediol dicaprylate) sold under the name DUB ZENOAT by Stearinerie Dubois, or diesters of glycols and monocarboxylic acids, such as, for example, neopentyl glycol diheptanoate, propylene glycol dioctanoate, diethylene glycol diisononanoate, or polyglyceryl-2-diisostearate (in particular, the compound sold under the trade designation DERMOL DGDIS by Alzo), (4.4) Hydroxylated monoesters and diesters, preferably those having 18 to 70 carbon atoms, such as polyglyceryl-3 diisostearate, isostearyl lactate, octyl hydroxystearate, octyldodecyl 1'-hydroxystearate, diisostearyl maleate, glycerol stearate; (4.5) triesters, in particular triesters of glycols and monocarboxylic acids with 35 to 70 carbon atoms, such as triisostearyl citrate or tridecyl trimellitate triesters of tricarboxylic acids, or polyglycerol-2 triisostearate, (4.6) Tetraesters, in particular those having a total carbon number in the range from 35 to 70, such as pentaerythritol tetraesters or polyglycerol tetraesters and carboxylic monoacids, such as pentaerythrityl tetrapelargonate, pentaerythrityl tetraisostearate, pentaerythrityl tetradecanoate, glyceryl tridecyl-2 tetradecanoate, polyglyceryl-2 tetraisostearate, or even pentaerythrityl tetradecyl-2 tetradecanoate. (4.7) Polyesters obtained by condensation of unsaturated fatty acid dimers and / or trimers with diols, such as those described in French Patent Application No. 0 853 634, for example, in particular, dilinoleic acid and 1,4-butanediol. In this regard, in particular, the polymer sold by Biosynthis under the name Viscoplast 14436H (INCI name: dilinoleic acid / butanediol copolymer), or also copolymers of polyols with diacid dimers and their esters, for example, Hailucent ISDA; (4.8) Esters and polyesters of diol dimers with monocarboxylic or dicarboxylic acids, such as esters of diol dimers with fatty acids and esters of diol dimers with dicarboxylic acid dimers, in particular those obtainable from dicarboxylic acid dimers, in particular dicarboxylic acid dimers derived in particular from the dimerization of C8 to C34, in particular C12 to C22, in particular C16 to C20, more particularly C18 unsaturated fatty acids, such as esters of dilinoleic diacids and dilinoleic diol dimers, such as those sold under the trade names LUSPLAN DD-DA5 and DD-DA7 by Nippon Fine Chemical. (4.9) Polyesters obtained by esterification of at least one triglyceride of hydroxylated carboxylic acids, optionally unsaturated, with aliphatic monocarboxylic acids and with aliphatic dicarboxylic acids, such as succinic and isostearic castor oil sold under the name Zenigloss by Zenitech; (4.10) Vegetable hydrocarbon oils include, for example, triglycerides of fatty acids (liquid at room temperature), in particular triglycerides of fatty acids having 7 to 40 carbon atoms, such as heptanoic or octanoic acid, especially saturated triglycerides, such as caprylic / capric triglyceride and mixtures thereof, such as those sold by Cognis under the name Myritol 318, glyceryl triheptanoate, glycerol trioctanoate, C18-36 acid triglycerides, such as those sold by Stearineries Dubois under the name DUB, etc. Those sold under TGI24, jojoba oil, macadamia oil, apricot kernel oil, and unsaturated triglycerides such as castor oil, olive oil, simena oil, prakash oil, and other vegetable hydrocarbon oils such as camellia oil, avocado oil, camellia oil, hazelnut oil, camellia oil, cashew nut oil, argan oil, soybean oil, grapeseed oil, sesame oil, corn oil, wheat germ oil, rapeseed oil, sunflower oil, cotton oil, peanut oil. (4.11) as well as mixtures thereof, for example oils composed of mixtures of C8-C10 fatty acid monoesters with C12-C18 fatty alcohols, such as Miglyol Coco 810 (INCI name: Coconut-Capric / Caprate) from IOI Oleo GmbH.

[0089] In certain embodiments of the present invention, the oil-in-water emulsion does not include vegetable-based oils.

[0090] In certain embodiments of the present invention, the oil-in-water emulsion does not include canola oil.

[0091] Preferably, the one or more polar nonvolatile hydrocarbon oils are selected from among C10 to C26 monoalcohols, ester oils, in particular monoesters containing a total of at least 17 carbon atoms, diesters, which may or may not be hydroxylated, containing a total of at least 18 carbon atoms, in particular diesters having at least 35 carbon atoms, in particular triesters having at least 35 carbon atoms, in particular vegetable hydrocarbon oils having at least 35 carbon atoms, and mixtures thereof.

[0092] Non-polar non-volatile hydrocarbon oil As for non-polar, non-volatile oils, hydrogenated or non-hydrogenated paraffin oil, squalane, pentadecane, nonadecane, eicosane, isoeicosane, polybutene, polyisoprene, hydrogenated or non-hydrogenated polydecene, decene / butene copolymer, polybutene / polyisobutene copolymer, and mixtures thereof may be more specifically listed. An example of a mixture of non-polar, non-volatile hydrocarbon oils is Emogreen L15 sold by Seppic, which is a mixture of C15 to C19 alkanes.

[0093] Non-volatile silicone oil As regards silicone non-volatile oils, mention may be made, for example, of non-volatile non-phenylated silicone oils such as polydimethylsiloxanes.

[0094] Phenylated silicone oils such as diphenyldimethicone, phenyltrimethicone, trimethylsiloxyphenyldimethicone, diphenylsiloxyphenyltrimethicone, trimethylpentaphenyltrisiloxane, or tetramethyltetraphenyltrisiloxane, and mixtures thereof, may also be mentioned.Advantageously, the non-volatile silicone oil does not contain oxyalkylated C2-C3 groups (oxyethylenated, oxypropylenated) or glycerolated groups.

[0095] According to a particular embodiment of the present invention, the non-volatile oil is selected from polar non-volatile oils, in particular C10-C26 alcohols, ester oils, and vegetable oils, either alone or in mixture. Thus, as described above, the oil-in-water emulsion comprises at least one C10-C26 alcohol, preferably a C14-C24 alcohol. The mass percentage of the non-volatile oil is more particularly 4-65% by weight, preferably 5%-60%, and more preferably 10-30% by weight, based on the weight of the oil-in-water emulsion.

[0096] Volatile oils The oil-in-water emulsion according to the invention may optionally comprise at least one volatile oil. Within the meaning of the present invention, "volatile oil" means in particular an oil having a non-zero vapor pressure at ambient temperature and atmospheric pressure, in particular an oil having a vapor pressure in the range of 2.66 Pa to 40,000 Pa, in particular in the range of 2.66 Pa to 13,000 Pa, more particularly in the range of 2.66 Pa to 1,300 Pa. The volatile oil may be a hydrocarbon or a silicone.

[0097] In particular, non-polar volatile hydrocarbon oils having 8 to 16 carbon atoms may be mentioned, such as C8 to C16 iso-alkanes (also called isoparaffins), C8 to C16 branched alkanes such as isododecane, isodecane, isohexadecane, and oils sold under the trade names Isopars or Permetyl. Preferably, the volatile hydrocarbon oil is selected from volatile hydrocarbon oils having 8 to 16 carbon atoms and mixtures thereof, in particular from isododecane, isodecane, isohexadecane, and in particular isohexadecane. Mention may be made of linear volatile alkanes containing 8 to 16 carbon atoms, in particular 10 to 15 carbon atoms, more particularly 11 to 13 carbon atoms, such as n-dodecane (C12) and n-tetradecane (C14), sold under the names PARAFOL 12-97 and PARAFOL 14-97, respectively, by Sasol, and mixtures thereof, undecane-tridecane mixtures such as Cetiol Ultimate by BASF, the mixture of n-undecane (CH) and n-tridecane (C13) by Cognis, as obtained in Examples 1 and 2 of WO 2008 / 155059, and mixtures thereof, as well as ethers having up to 16 carbon atoms, such as dicaprylyl ether.

[0098] As silicone volatile oils, linear silicone volatile oils such as hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, tetradecamethylhexasiloxane, hexadecamethylheptasiloxane, and dodecamethylpentasiloxane can be listed. As cyclic silicone volatile oils, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane can be listed.

[0099] Advantageously, when included in an oil-in-water emulsion, the content of volatile oil ranges from 0.5 to 10% by weight, or from 1 to 5% by weight, relative to the weight of the oil-in-water emulsion.

[0100] wax: The oil-in-water emulsion according to the invention may optionally comprise at least one silicone wax or a polar or non-polar hydrocarbon wax. Waxes considered within the scope of the present invention are generally lipophilic compounds that are solid at room temperature (25°C) and have a reversible solid / liquid state change, in particular having a melting point of 30°C or higher, more particularly above 45°C. Advantageously, the melting point is 90°C or lower, more particularly 80°C or lower, preferably 70°C or lower. The melting point of the solid fatty substance can be measured using a differential scanning calorimeter (DSC), for example the calorimeter sold by TA Instruments under the name "DSC Q100" with the "TA Universal Analysis" software.

[0101] The measurement protocol is as follows: a sample of about 5 mg of solid fatty substance is placed in an "aluminum airtight capsule" crucible. The sample is subjected to a first temperature increase ranging from 20°C to 120°C at a heating rate of 2°C / min up to 80°C, then isothermal at 100°C for 20 minutes, then cooled from 120°C to 0°C at a cooling rate of 2°C / min, and finally subjected to a second temperature increase ranging from 0°C to 20°C at a heating rate of 2°C / min. The melting temperature value of the solid fatty substance is the maximum of the maximum endothermic peak of the observed melting curve and represents the variation of the difference in absorbed power as a function of temperature.

[0102] Polar Hydrocarbon Wax More specifically, the polar wax is selected from ester hydrocarbon waxes, alcohol hydrocarbon waxes, silicone waxes, and mixtures thereof. A "hydrocarbon wax" is understood to mean a wax essentially formed by or further consisting of carbon and hydrogen atoms, and optionally oxygen or nitrogen atoms, and not containing silicon atoms or fluorine. This may contain alcohol, ester, ether, carboxylic acid, amine, and / or amide groups. According to the present invention, an "ester wax" is understood to mean a wax containing at least one ester functional group. Ester waxes can also be hydroxylated. According to the present invention, an "alcohol wax" is understood to mean a wax containing at least one alcohol functional group, in other words, a wax containing at least one free hydroxyl group (OH). Additional alcohol waxes, in particular, do not contain ester functional groups. A "silicone wax" is understood to mean a wax containing at least one silicon atom, in particular a wax containing an Si—O group.

[0103] Ester Wax: In particular, the following can be used as ester waxes: i) waxes of the formula R1-COO-R2, where R1 and R2 represent linear, branched or cyclic aliphatic chains, the number of atoms of which varies from 10 to 50 and which may contain heteroatoms, in particular oxygen, and whose melting point temperature varies from 30 to 120°C, preferably from 30 to 100°C. In particular, as ester waxes, C20-C40 alkyl(hydroxystearyloxy)stearates (alkyl groups containing 20 to 40 carbon atoms), alone or in mixtures, or C20-C40 alkyl stearates can be used. Such waxes are sold, in particular, by KOSTEER KEUNEN under the names "KEster Wax 82P®", "Hydroxypolyester K82®", "KEster Wax K80®" or "KEster Wax K82H". Mixtures of esters of C14-C18 carboxylic acids and alcohols can also be used, such as the "Cetyl Ester Wax 814" product from Kosteer Keunen, "SP Crodamol MS MBAL" and "Crodamol MS PA" from Croda, and "Miraceti" from Laserson. Glycol and butylene glycol montanate (octacosanoate) waxes can also be used, such as LICOWAX KPS FLAKES (INCI name: Glycol Montanate) wax sold by Clariant. ii) Di-(trimethylol-1,1,1-propane) tetrastearate sold under the name Hest 2T4S® by HETERENE. iii) Diester waxes of dicarboxylic acids of the general formula R3-(-OCO-R4-COO-R5), wherein R3 and R5 are the same or different, preferably the same, and represent a C4-C30 alkyl group (an alkyl group having 4 to 30 carbon atoms), and R4 represents a linear or branched C4-C30 aliphatic group (an alkyl group having 4 to 30 carbon atoms), which may or may not contain one or more unsaturated bonds. Preferably, the C4-C30 aliphatic group is linear and unsaturated. iv) Waxes obtained by catalytic hydrogenation of animal or vegetable oils, especially those with linear or branched fatty chains of C8 to C32, such as hydrogenated jojoba oil, hydrogenated sunflower oil, hydrogenated castor oil, hydrogenated copra oil, etc., as well as waxes obtained by hydrogenation of castor oil esterified with cetyl alcohol, such as those sold by SOPHIM under the names Phytowax ricin 16L64® and 22L73®. Such waxes are described in French Patent Application Publication No. 2792190(A). The wax sold under the name "Phytowax Olive 18 L57" can be listed as a wax obtained by hydrogenation of olive oil esterified with stearyl alcohol. v) Waxes of animal or vegetable origin may be used, such as beeswax, synthetic beeswax, carnauba wax, candelilla wax, lanolin wax, rice bran wax, ouricle wax, alpha wax, berry wax, shellac wax, cork fiber wax, sugarcane wax, Japan wax, hazel wax, montan wax, orange and lemon wax, bay leaf wax, hydrogenated jojoba wax, sunflower wax, and especially refined waxes. vi) Waxes, hydrocarbon, polyoxyalkylenated or polyglycerolated, natural or synthetic, of animal or vegetable origin, may also be mentioned, the number of oxyalkylenated units (C2-C4) may vary from 2 to 100 and the number of glycerolated units may vary from 1 to 20. Examples that may be mentioned include polyoxyethylenated beeswax, such as PEG-6 beeswax, PEG-8 beeswax, polyoxyethylenated carnauba wax, such as PEG-12 carnauba, hydrogenated or non-hydrogenated, polyoxyethylenated or polyoxypropylenated lanolin wax, such as PEG-30 lanolin, PEG-75 lanolin, glycerides of PPG-5 lanolin wax, polyglycerolized beeswax, in particular polyglyceryl-3 beeswax, mixtures of wattle, jojoba, sunflower seed wax, and polyglyceryl-3 esters, polyglycerolized vegetable waxes, such as mimoba, jojoba, sunflower wax, and mixtures thereof (wattle, jojoba, sunflower seed wax, polyglyceryl-3 esters). vii) waxes corresponding to partial or total esters, preferably total esters, of saturated, optionally hydroxylated C16 to C30 carboxylic acids with glycerol. Total esters are understood to mean that all hydroxylated functional groups of glycerol are esterified. Examples include trihydroxystearin (i.e., glyceryl trihydroxystearate), tristearin (i.e., glyceryl tristearate), and tribehenin (i.e., glyceryl tribehenate), either alone or in mixtures. Among suitable compounds, mention may be made of glycerol triesters and 12-hydroxystearic acid, or hydrogenated castor oil, such as Thixcin R and Thixcin E, sold by Elementis Specialties. viii) as well as mixtures thereof can be used.

[0104] Alcohol wax The alcohol wax is preferably a linear, preferably saturated alcohol containing 16 to 60 carbon atoms and having a melting point in the range of 25° C. to 90° C. Examples of alcohol waxes include stearyl alcohol, cetyl alcohol, myristyl alcohol, palmityl alcohol, behenic alcohol, erucic alcohol, arachidyl alcohol, or mixtures thereof.

[0105] Non-polar hydrocarbon wax The oil-in-water emulsion can optionally contain at least one additional wax selected from non-polar hydrocarbon waxes. Within the meaning of the present invention, "non-polar hydrocarbon wax" is understood to mean a wax containing only carbon or hydrogen atoms in its structure. In other words, such waxes do not contain other atoms, particularly heteroatoms, such as nitrogen, oxygen, silicon, etc. As examples of exemplary non-polar waxes suitable for the present invention, hydrocarbon waxes such as microcrystalline wax, paraffin wax, ozokerite, polymethylene wax, polyethylene wax, waxes obtained by Fischer-Tropsch synthesis, microcrystalline waxes, especially polyethylene, can be mentioned in particular.

[0106] silicone wax For example, a mixture containing a C30-45 alkyldimethylsilylpolypropylsilsesquioxane (INCI name) compound can be listed as a silicone wax, such as the Dow Corning SW-8005 C30 Resin Wax product sold by Dow Corning. A mixture containing a C30-45 alkylmethionine (INCI name) compound, such as the Dow Corning® AMS-C30 Cosmetic Wax product, can also be listed. Silicone beeswax can also be listed. The oil-in-water emulsion according to the present invention can contain 0.5 to 10 wt. %, or 0.5 to 6 wt. %, or 1 to 4 wt. % of a wax, preferably a polar wax, preferably a hydrocarbon wax, based on the weight of the composition.

[0107] The emulsion according to the present application may be an O / W emulsion with a very high oil content. This type of oil-rich O / W emulsion is usually difficult to obtain in a stable form for a long period of time using conventional emulsifiers. The oil content of the final O / W emulsion is preferably 10 to 65% by weight, preferably about 20 to 55% by weight. For example, vegetable-based or vegetable-derived oils, such as sunflower oil and isopropyl palmitate, can provide particularly stable emulsions that do not cause creaming or phase separation.

[0108] Rheological agents (or hydrophilic thickeners) The emulsion according to the invention may further comprise a rheological agent, in particular a thickener, gelling agent or suspending agent for the aqueous phase. The rheological agent may be selected from gums of plant origin such as gum arabic, konjac gum, guar gum or derivatives thereof; gums extracted from algae such as alginates or carrageenans; gums obtained by microbial fermentation such as xanthan, mannan, scleroglucan or derivatives thereof; cellulose and its derivatives such as carboxymethylcellulose or hydroxyethylcellulose; microcrystalline cellulose; starch and its derivatives, in particular starch modified with acetylated, carboxymethylated or hydroxypropylated hydrophilic or ionic groups; and hydrophilic thickeners which are synthetic polymers such as polyacrylic acid or carbomer.

[0109] Preferably, the emulsion according to the present application comprises a rheological agent chosen from natural polysaccharides of plant or fermentation origin, optionally modified, used in a content ranging from 0.1% to 1% by weight of the total emulsion.

[0110] Preferably, the plant- or microbial-derived gum is a nonionic polysaccharide. Fermentation-derived gums, such as xanthan, gellan, mannan, and scleroglucan, are preferred, especially xanthan and scleroglucan, and more particularly xanthan. Such xanthan gums generally have a molecular weight of 1,000,000 to 50,000,000 Da. Examples of commercially available xanthan gums include the Xanthan Gum FNCS-PC product available from Jungbunzlauer International AG, the Keltrol® CG-T product available from CP Kelco, the Cosphaderm® X 17 product available from Cosphatec, the Kahlgum 6673 FEE-Xanthan Gum product available from KahlWax, the Rhodicare® S and Rhodicare® XC products available from Solvay, and the VANZAN® NF-C product available from Vanderbilt Minerals.

[0111] As the cellulose derivative, modified celluloses can be selected, in particular methylcellulose, hydroxyalkylcellulose, ethylhydroxyethylcellulose, methylethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, with carboxymethylcellulose and hydroxyethylcellulose being preferred, and hydroxyethylcellulose being the most preferred. In particular, the following commercial products can be mentioned: Natrosol® 250 HHR PC available from Ashland Specialty Chemical; Espesante CH available from Chemir; Tylose® H 15 YG4 available from SE Tylose and Cellosize® HEC QP 40 available from DowDuPont (Dow).

[0112] According to one embodiment, the rheological agent is selected from xanthan, guar, carob or tara gum, or hydroxyethylated cellulose, microcrystalline cellulose, or mixtures thereof. According to a highly preferred embodiment, the rheological agent is xanthan gum.

[0113] Brookfield Viscosity: Brookfield viscosity is measured at 20°C using a Brookfield DV-II+Pro viscometer equipped with an appropriately selected SP1, SP2, or SP3 spindle, which rotates in contact with the product sample at a speed of 20 revolutions per minute. The resistance of the emulsion to this rotational motion is recorded over a period of 1 minute and converted to millipascal-seconds, commonly denoted mPa.s. Under these measurement conditions, the spindle rotates at a rate of approximately 0.1 s -1 For each emulsion sample, the viscosity is measured three times and the arithmetic mean of the three values ​​is kept. The selection of a spindle suitable for the viscosity to be measured is made according to the following ranges: if the viscosity is 500 mPa.s or less, the spindle selected is the SP1 spindle; - When the viscosity is 500 mPa.s to 5,000 mPa.s, the spindle to be selected is the SP2 spindle; When the viscosity is between 5,000 mPa.s and 10,000 mPa.s, the spindle to be selected is the SP3 spindle.

[0114] For viscosities above 5,000 mPa.s, the following spindles can be selected: SP4 if the viscosity is between 10,000 mPa.s and 20,000 mPa.s, SP5 if the viscosity is between 20,000 and 50,000 mPa.s.

[0115] According to one embodiment, the emulsion according to the present application preferably has a Brookfield viscosity at 20°C of less than 3,000 mPas, or 2,800 mPas or less, or 2,600 mPa.s or less, or 2,250 mPa.s or less, or 2,000 mPa.s or less, or 1,750 mPa.s or less, or 1,500 mPa.s or less, or 1,000 mPa.s or less, or 500 mPa.s or less, or 100 mPa.s or less.

[0116] According to one embodiment complementary to the preceding embodiment, the emulsion has a Brookfield viscosity of 10 mPa.s or more, or 20 mPa.s or more, or 30 mPa.s or more, or 50 mPa.s or more, or 60 mPa.s or more, or 70 mPa.s or more, or 80 mPa.s or more, or 90 mPa.s or more.

[0117] Characteristic size of the dispersed phase The emulsions according to the present application preferably have a droplet size of 30 μm or less, preferably 10 μm or less. Emulsion droplet size should be understood to mean the average diameter of the dispersed fatty phase droplets suspended in the aqueous phase. A small droplet size reduces the rate of emulsion coalescence and the rate of phase separation, thereby improving emulsion stability. The droplet size depends on many parameters and therefore must be controlled, and is a non-specific characteristic of the formulation of an emulsifying system. The droplet size is measured using a LEICA DMLS optical microscope at 10x magnification.

[0118] Emulsification method The object of the present application is a method for emulsifying an oil phase in an aqueous phase to obtain an oil-in-water emulsion having a Brookfield viscosity of less than 3,000 mPa.s, preferably less than 2,000 mPa.s, more preferably less than 1,000 mPa.s, most preferably less than 500 mPa.s, at 20°C and 20 rpm using an SP5 spindle for 1 minute, the method comprising: a) providing an aqueous phase; b) solubilizing an emulsifier system consisting of at least one starch-derived emulsifier and at least one cyclodextrin in an aqueous phase to obtain a homogeneous aqueous phase; c) emulsifying the oil phase in the aqueous phase by stirring at a rotation speed of 7,500 rpm or less, preferably in the range of 1,000 to 7,500 rpm, preferably 2,000 to 5,000 rpm, more preferably 2,500 to 4,000 rpm.

[0119] The stirring speed chosen for the emulsification method according to the invention makes it possible to generate shear rates that are considered medium to low in the field of emulsification, where values ​​of 10,000 rpm or even 20,000 rpm are more common.

[0120] Preferably, the emulsion has a Brookfield viscosity at 20°C and 20 rpm for 1 minute using an SP1 spindle of 10 mPa.s or more, or 20 mPa.s or more, or 30 mPa.s or more, or 50 mPa.s or more, or 60 mPa.s or more, or 70 mPa.s or more, or 80 mPa.s or more, or 90 mPa.s or more.

[0121] The emulsification method can include an additional step b') consisting of solubilizing a low molecular weight emulsifying surfactant at a content of less than or equal to 1% by weight of the total emulsion, preferably less than or equal to 0.5%, more preferably less than or equal to 0.1%, this step preferably being carried out before step c).

[0122] According to one embodiment, step b) is carried out using a starch-based or starch-derived emulsifier having a solubility in water of 50% or more, or 75% or more, or 85% or more, or 95% or more, or 98% or more, or 99% or more, or 100% at 22°C according to test A.

[0123] Preferably, the emulsifier system of step b) may further provide cyclodextrin in an amount representing 2.5 to 6% by weight, preferably 3 to 5% by weight, more preferably 3.5 to 4.5% by weight, or 2.5 to 4% by weight relative to the total weight of the emulsion.

[0124] Preferably, the emulsifier system of step b) may further provide a starch-based or starch-derived emulsifier in an amount representing 1 to 7% by weight, preferably 1.5 to 6% by weight, more preferably 2 to 5% by weight, most preferably 2.5 to 4.5% by weight, or 1.0 to 2.5% by weight, relative to the total weight of the emulsion.

[0125] Preferably, the emulsifier system, consisting of at least one starch-derived emulsifier and at least one cyclodextrin, is the only emulsifier introduced into the process.

[0126] Preferably, the temperature of the present process is between 10°C and 60°C, preferably between 15°C and 40°C, more preferably between 18°C ​​and 30°C.

[0127] Solubilization of the emulsifier system is substantially complete in the aqueous phase, i.e., at least 50%, better at least 75%, and even better 85% or more at 22°C. Ideally, at least 95% by weight, preferably at least 98% by weight, more preferably at least 99% by weight, and most preferably 100% by weight of the emulsifier system is solubilized in the aqueous phase. In one embodiment, all solid particles of the emulsifier system are solubilized in the aqueous phase. Thus, the aqueous phase does not contain solid particles of or derived from the emulsifier system.

[0128] One advantage of the emulsification method encompassed by the present application is that it can be carried out at moderate temperatures, for example, below 60° C. to low temperatures, for example, below 30° C. This method makes it possible to avoid the need for high temperatures, particularly above 60° C.

[0129] Another advantage of the emulsification method encompassed by the present application is that emulsification can be carried out under moderate to low shear-inducing stirring, thus avoiding heating of the emulsion.Compared to high-shear emulsification, the total energy consumption of the emulsification method is lower, and in particular the amount of energy dissipated in the emulsified medium is reduced, which is preferable for maintaining the integrity of the polymer structure of the starch-derived emulsifier and not decomposing other heat-sensitive components introduced into the emulsion.In fact, anhydroglucose polymer chains, like those of other molecules, are susceptible to breakage under the influence of high shear, especially when combined with high temperature.This breakage leads to a decrease in the ability of the starch-derived emulsifier to emulsify oil in water. In order to maximize the emulsifying power of the starch-derived emulsifier, it is essential that the starch-derived emulsifier retains sufficient polymer structure, i.e., a weight average molecular weight, preferably in the range of 10 to 2,000 kDa, or 20 to 1,500 kDa, or 30 to 1,000 kDa, or 40 to 800 kDa, or 45 to 700 kDa, as measured by HPSEC-MALLS.

[0130] The methods encompassed by the present application effectively preserve the complexity of the starch polymer chains, thereby maximizing their ability to emulsify an oil phase in an aqueous phase.

[0131] The oil-in-water emulsions and cosmetic compositions encompassed by the present application are advantageously prepared by an emulsification method as defined above, using medium to low shear forces, optionally at medium to low temperatures. [Example]

[0132] Example 1: Preparation of a sunflower oil emulsion according to the invention Oil-in-water emulsions were prepared from sunflower oil by combining the natural β-cyclodextrin "Beauté by Roquette® CD 102" with starch-based emulsifiers selected from two water-soluble octenyl succinate starches Cleargum® CO 01 and Cleargum® CO 03 and the water-soluble octenyl succinate dextrin Cleargum® CO A1, according to the composition in Table 1, at mass contents ranging from 2.5 to 4% by weight of the emulsion for the β-cyclodextrin and from 1 to 4% by weight of the emulsion for the starch-based emulsifiers, for an oil mass fraction of 30% by weight of the emulsion.

[0133] [Table 1]

[0134] To prepare each emulsion, an aqueous phase was prepared by dispersing the required amount of cyclodextrin and starch-derived emulsifier in the required total mass of water at 40-45°C while stirring with a deflocculating paddle at 1,000 rpm for 10 minutes. The oil mass, preheated to 40-45°C, was then added to the aqueous phase while stirring with a deflocculating paddle at 3,000-3,300 rpm (which corresponds to low shear according to the present application) for 15 minutes. It was then cooled to 20°C, and the pH was adjusted to 6. The emulsion was then left at 20°C for 48 hours.

[0135] Forty-eight hours after the emulsions were prepared, Brookfield viscosities were measured at 20° C. with an SP5 spindle at 20 rpm for 1 minute and expressed in mPa s after a 48-hour rest period. The results are shown in Table 2 for the combination of β-cyclodextrin and Cleargum CO 03, Table 3 for the combination of β-cyclodextrin and Cleargum CO 01, and Table 4 for the combination of β-cyclodextrin and Cleargum CO A1.

[0136] [Table 2]

[0137] [Table 3]

[0138] [Table 4]

[0139] Thus, it was found that emulsions prepared using a combination of cyclodextrin and a starch-derived emulsifier selected from Cleargum® CO 03, CO 01, and CO A1 effectively had viscosities of less than 3,000 mPa.s, and that the viscosity of the emulsions appeared to be adjustable by varying the amounts of cyclodextrin and starch-derived emulsifier, respectively. Furthermore, it was found that the viscosity of emulsions prepared in this manner was lower than that of emulsions formed using cyclodextrin alone (and thus, without the starch-derived emulsifier). Finally, it was also found that emulsions prepared using at least 1% by weight of a starch-based emulsifier and at least 2.5% by weight of cyclodextrin were stable for 48 hours and up to 6 months after preparation.

[0140] Regarding the possibility of creating an emulsion without β-cyclodextrin using only one of the octenyl succinate-modified starches of this example, an attempt was made to prepare emulsion No. 15 using 65.6 wt. % water, 4 wt. % Cleargum CO 03 starch, and 30 wt. % sunflower oil. Although initially appearing as an emulsion with a viscosity of 950 mPa.s, a heterogeneous mixture was obtained that rapidly exhibited marbling and then phase demixing in less than 24 hours. Thus, an emulsion could not be formed in the absence of β-cyclodextrin.

[0141] Example 2: Preparation of a sunflower oil emulsion outside the invention An oil-in-water emulsion was prepared from sunflower oil by combining the natural β-cyclodextrin "Beaute by Roquette® CD 102" and the octenylsuccinate modified granular starch Beaute by Roquette® ST 012 according to the composition in Table 5, at a content of 4% by weight of the emulsion for the β-cyclodextrin and 1.5-4% by weight of the emulsion for the octenylsuccinate granular starch, so that the mass oil fraction of the emulsion is 30% by weight.

[0142] To prepare each emulsion, an aqueous phase was prepared by dispersing the required amount of cyclodextrin and starch-derived emulsifier in the required total mass of water at 40-45°C while stirring with a deflocculating paddle at 1,000 rpm for 10 minutes. The oil mass, preheated to 40-45°C, was then added to the aqueous phase while stirring with a deflocculating paddle at 3,000-3,300 rpm (which corresponds to low shear according to the present application) for 15 minutes. It was then cooled to 20°C, and the pH was adjusted to 6. The emulsion was then left at 20°C for 48 hours.

[0143] 48 hours after the emulsions were prepared, the Brookfield viscosity was measured at 20° C. with an SP5 spindle at 20 rpm for 1 minute and expressed in mPa.s after a 48 hour rest period. The results are shown in Table 5.

[0144] [Table 5]

[0145] Emulsions prepared with octenyl succinate granular starch and β-cyclodextrin had higher viscosities (2,500-3,000 mPa.s) than those achieved with the water-soluble octenyl succinate starch of Example 1. Furthermore, these emulsions were found to be unstable within 48 hours of preparation: marbling appeared, signs of phase demixing appeared, and optical microscopy revealed non-spherical oil particles indicative of coalescence.

Claims

1. An oil-in-water emulsion comprising: an oil phase dispersed in an aqueous phase; an emulsifier system consisting of at least one cyclodextrin and at least one starch-based emulsifier and / or emulsifier derived from starch, the emulsion has a Brookfield viscosity at 20 rpm for 1 minute using an SP5 spindle at 20°C of less than 3,000 mPa s, preferably 2,800 mPa s or less, preferably 2,600 mPa s or less; An oil-in-water emulsion, wherein the starch-based emulsifier and / or the starch-derived emulsifier has a solubility in water at 22°C according to Test A of 50% or more, or 75% or more, or 85% or more, or 95% or more, or 98% or more, or 99% or more, or 100%.

2. 2. An oil-in-water emulsion according to claim 1, wherein the mass content of the at least one cyclodextrin relative to the total weight of the emulsion is in the range from 2.5 to 6%, from 3 to 5%, most preferably from 3.5 to 4.5%, or from 2.5 to 4% by weight of the emulsion.

3. 3. An oil-in-water emulsion according to claim 1 or 2, wherein the mass content of the at least one starch based and / or starch derived emulsifier relative to the total weight of the emulsion is in the range of 1 to 7%, 1.5 to 6%, 2 to 5%, most preferably 2.5 to 4.5%, or 1.0 to 2.5% by weight of the emulsion.

4. 4. An oil-in-water emulsion according to any one of claims 1 to 3, wherein the emulsion has a Brookfield viscosity using an SP1 spindle at 20 rpm for 1 minute at 20°C of more than 10 mPa s, preferably 20 mPa s or more, preferably 30 mPa s or more, preferably 50 mPa s or more.

5. 5. An oil-in-water emulsion according to any one of claims 1 to 4, wherein the emulsion is biodegradable to more than 90%, in particular more than 93%, according to OECD standard 301 F.

6. 6. An oil-in-water emulsion according to claim 5, comprising less than 1% by weight, preferably less than 0.5% by weight, preferably 0% by weight of surfactants having a molecular weight or weight average molecular weight of 250 Da or less, preferably 500 Da or less, preferably 750 Da or less, preferably 1 kDa or less, preferably 10 kDa or less.

7. 7. An oil-in-water emulsion according to claim 6, wherein the at least one cyclodextrin is selected from natural and modified cyclodextrins, preferably natural or modified α-, γ- or β-cyclodextrin, more preferably natural α-, γ- or β-cyclodextrin, and most preferably natural β-cyclodextrin.

8. 8. An oil-in-water emulsion according to claim 7, wherein the starch-based or starch-derived emulsifier is starch, dextrin or maltodextrin.

9. 9. An oil-in-water emulsion according to any one of claims 1 to 8, wherein the at least one starch-based emulsifier and / or the starch-derived emulsifier comprises at least one amphiphilic group, preferably at least one alkenyl succinate group, preferably at least one alkali metal or alkaline earth metal octenyl succinate group, most preferably at least one sodium or calcium octenyl succinate group, even more preferably a sodium octenyl succinate group.

10. 10. An oil-in-water emulsion according to any one of claims 1 to 9, wherein the starch is a starch modified by pregelatinization, gelatinization, spray drying, acid hydrolysis, or enzymatic hydrolysis, or a combination of these modifications, preferably the starch is a hydrolyzed and pregelatinized starch.

11. 11. An oil-in-water emulsion according to any one of claims 1 to 10, wherein the starch-based or starch-derived emulsifier is selected from octenylsuccinate pregelatinized starch, octenylsuccinate gelatinized starch, octenylsuccinate hydrolyzed starch, octenylsuccinate hydrolyzed and pregelatinized starch, octenylsuccinate dextrin, octenylsuccinate maltodextrin, and mixtures thereof.

12. 12. An oil-in-water emulsion according to any one of claims 1 to 11, wherein the starch-based or starch-derived emulsifier is selected from octenylsuccinate pregelatinized starch, octenylsuccinate gelatinized starch, octenylsuccinate hydrolyzed starch, octenylsuccinate hydrolyzed and pregelatinized starch, and mixtures thereof.

13. 13. An oil-in-water emulsion according to any one of the preceding claims, wherein the ratio of the weight of the starch-based or starch-derived emulsifier to the weight of the cyclodextrin is in the range from 0.2 to 2, preferably from 0.3 to 1.6, preferably from 0.4 to 1.2, preferably from 0.5 to 1, preferably from 0.55 to 0.9, most preferably from 0.60 to 0.

80.

14. 14. Oil-in-water emulsion according to any one of the preceding claims, characterized in that the mass content of said emulsifier system in the emulsion is at least 3.5% by weight, preferably at least 4% by weight, preferably at least 4.5% by weight, preferably at least 5% by weight.

15. 15. An oil-in-water emulsion according to any preceding claim, wherein the emulsifier system is the only emulsifier present in the emulsion.

16. 16. An oil-in-water emulsion according to any one of the preceding claims, containing native or modified granular starch, preferably modified amphiphilic granular starch, more preferably octenyl succinate granular starch, in an amount equal to or less than 5% by weight, preferably equal to or less than 2% by weight, more preferably equal to or less than 1% by weight, even more preferably equal to or less than 0.5% by weight and most preferably equal to 0% by weight, relative to the total weight of the emulsion.

17. 1. A process for emulsifying an oil phase in an aqueous phase to obtain an oil-in-water emulsion having a Brookfield viscosity at 20°C, 20 rpm using an SP5 spindle for 1 minute of less than 3000 mPa s, preferably less than 2000 mPa s, more preferably less than 1000 mPa s, and most preferably less than 500 mPa s, said process comprising: a) providing an aqueous phase; b) solubilizing an emulsifier system consisting of at least one starch-based or starch-derived emulsifier and at least one cyclodextrin in an aqueous phase to obtain a homogeneous aqueous phase; c) emulsifying the oil phase in the aqueous phase by stirring at a rotational speed of 7,500 rpm or less.

18. 18. An oil-in-water emulsion, characterized in that it is obtained by the emulsification method according to claim 17.

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