JP6265331B2 - Cellobiose lipid salt and uses thereof - Google Patents

Description

  The present invention relates to a salt of cellobiose lipid and use thereof.

  Glycolipid is an amphiphilic substance having two properties of hydrophilicity derived from the properties of the sugar moiety and lipophilicity derived from the properties of the lipid portion, and has a function as a surfactant. Various amphipathic substances exist in the living body, and are involved in the exchange of substances, energy, information, etc. at various interfaces, and play a large role in the formation of order in the living body.

  The existence of microorganisms that produce these surfactants is known. This microorganism-derived surfactant (biosurfactant) is highly safe and excellent in biodegradability, so it has less impact on the environment than synthetic surfactants, and it cannot be easily produced by synthesis. It has a complicated structure and is known to have excellent physiological functions. For example, glycolipid-based biosurfactants are known to have a high moisturizing effect per se, and are expected to be used as ingredients in cosmetics and the like. Since biosurfactants have such specificities, research is being conducted in various fields such as the food industry, the cosmetics industry, the pharmaceutical industry, the chemical industry, and the environmental field.

  In recent years, cellobiose lipid, which is a kind of glycolipid biosurfactant, has been reported to show antifungal activity and has attracted attention (see Non-Patent Document 1). Cellobiose lipid is known to be produced by Ustilago maydis and Cryptococcus humicola (see Non-Patent Document 2). Pseudozyma flocculosa is also known to produce floculosine, a type of cellobiose lipid (see Non-Patent Document 3). Furthermore, it is known that Ustilago esculenta can produce cellobiose lipid in large quantities (see Patent Document 1).

  Cellobiose lipids are industrially used in a wide range of fields such as detergents and cosmetics. For example, liposome forming agents (see Patent Document 2), emulsifiers / solubilizers (see Patent Document 3), protein separation carriers (Refer patent document 4), utilization examples, such as low molecular organogel (refer patent document 5), are reported.

JP 2004-254595 A JP 2006-028069 A JP 2007-181789 A JP 2006-219455 A JP 2012-176904 A

J. Oleo Sci., Vol.58, No.3, p.133-140, 2009 Biochim. Biophys. Acta, Vol. 1558, No. 2, p. 161-170, 2002 Appl. Environ. Microbiol., Vol.69, No.5, p.2595-2602, 2013

  The present invention has been made in view of the above-described current state of the prior art, and an object thereof is to provide an improved technique and a new application of cellobiose lipid.

  Although cellobiose lipids usually show poor solubility in water, the present inventors prepared a salt of cellobiose lipid and examined its solubility in an aqueous solvent. Surprisingly, the salt of cellobiose lipid was found to be an aqueous solvent. It was found to dissolve easily. Even more surprisingly, it has been found that aqueous solutions containing cellobiose lipid salts form aqueous gels and aqueous sols. The aqueous gel transitions from a gel state to a sol state with a relatively small strain, and reversibly transitions from a gel state to a sol state or from a sol state to a gel state depending on temperature. It was found to have excellent characteristics. Based on this finding, the present inventors have completed the present invention through further research and consideration.

That is, the present invention typically provides the inventions described in the following sections.
Item 1.
Cellobiose lipid salt.
Item 2.
Item 2. The cellobiose lipid salt according to Item 1, wherein the salt is an alkali metal salt or an alkaline earth metal salt.
Item 3.
Item 3. The cellobiose lipid salt according to Item 2, wherein the alkali metal salt is a sodium salt or a potassium salt.
Item 4.
The composition containing the salt of the cellobiose lipid in any one of said claim | item 1-3.
Item 5.
Item 5. The composition according to Item 4, comprising 0.1 to 30% by mass of a cellobiose lipid salt.
Item 6.
Item 6. The composition according to Item 4 or 5, which is an aqueous composition.
Item 7.
Item 7. The composition according to any one of Items 4 to 6, which is a gel or sol composition.
Item 8.
Item 4. A thickener containing the cellobiose lipid salt according to any one of items 1 to 3.
Item 9.
Item 9. The composition according to any one of Items 4 to 8, which is used as a compounding agent for cosmetics, quasi-drugs, medical products, hygiene products, pharmaceuticals, or food and drink.
Item 10.
The manufacturing method of aqueous gel including the process of leaving still the aqueous solution containing the salt of the cellobiose lipid in any one of said claim | item 1-3 at 48 degrees C or less.

  Since the salt of cellobiose lipid of the present invention has significantly improved solubility in an aqueous solvent such as water as compared with cellobiose lipid, viscosity can be imparted to the aqueous solvent containing the salt of cellobiose lipid. Therefore, the cellobiose lipid salt of the present invention can be used as a thickener, a gelling agent, a viscosity modifier and the like.

  Furthermore, since the salt of cellobiose lipid of the present invention is obtained from a cellobiose lipid derived from a microorganism, it is highly biodegradable and low in comparison with a polymer compound conventionally used as a component such as a thickener. Toxic and environmentally friendly thickeners can be provided.

  In addition, the cellobiose lipid salt of the present invention provides a new gel-like or sol-like composition because an aqueous gel or aqueous sol is formed by incorporating an aqueous component in a system in which an aqueous component such as water is present. be able to.

  In addition, the aqueous gel formed by the cellobiose lipid salt of the present invention has a characteristic that it transitions from a gel state to a sol state by a relatively small strain, and a gel-sol transition occurs at a relatively mild temperature. It is possible to provide new cosmetics, quasi-drugs, medical supplies, hygiene products, pharmaceuticals, foods and drinks and the like using the characteristics such as controlled release of the active ingredient contained in the gel.

The result of having measured the angular frequency ((omega)) dependence of the storage elastic modulus (G ') and loss elastic modulus (G ") of water gel is shown. The measurement result of the strain (γ) dependence of the storage elastic modulus (G ′) and loss elastic modulus (G ″) of the aqueous gel is shown. The result of having measured the temperature dependence of the storage elastic modulus (G ') and loss elastic modulus (G ") of aqueous gel is shown.

  Hereinafter, the present invention will be described in detail.

Cellobiose lipid Cellobiose lipid (hereinafter sometimes referred to as “CL”) may have various molecular structures depending on the type of microorganisms that produce it. For example, microorganisms belonging to the genus Cryptococcus mainly produce cellobiose lipid having a structure represented by the following structural formula (I), and microorganisms belonging to the genus Ustilago are mainly represented by the following structural formula (II). It is known to produce cellobiose lipids having the structure described above.

（式（Ｉ）中、Ｒ_１は、水素原子又はヒドロキシル基であり、Ｒ_２、Ｒ_３及びＲ_４は、同一又は異なって、アセチル基又はヒドロキシル基であり、ｎ１は、１２〜１４の整数を表す。）

(In Formula (I), R ₁ is a hydrogen atom or a hydroxyl group, R ₂ , R ₃ and R ₄ are the same or different, and are an acetyl group or a hydroxyl group, and n1 is an integer of 12 to 14) Represents.)

（式（ＩＩ）中、Ｒ_１及びＲ_２は、同一又は異なって、水素原子またはヒドロキシル基であり、ｎ１は１１又は１２であり、ｎ２は２〜４の整数を表す。）

(In formula (II), R ₁ and R ₂ are the same or different and are a hydrogen atom or a hydroxyl group, n1 is 11 or 12, and n2 represents an integer of 2 to 4.)

  Although the manufacturing method of cellobiose lipid is not specifically limited, For example, it can obtain by culturing a cellobiose lipid producing microorganism, extracting and refine | purifying from the said culture solution.

  The cellobiose lipid-producing microorganism is not particularly limited as long as it is a microorganism having cellobiose lipid-producing ability. ), Ustilago maydis, Pseudozyma flocculosa belonging to the genus Pseudozyma, Pseudozyma graminicola, and the like.

  The method for culturing the cellobiose lipid-producing microorganism is not particularly limited, and the medium composition, the culture conditions such as pH and temperature, the culture time, etc. may be appropriately determined according to the cellobiose-producing microorganism to be used.

  When cellobiose lipid is produced by culturing cellobiose lipid-producing microorganisms, the cultured medium after culture may be used as it is as cellobiose lipid, and the cultured medium after culture may be filtered, centrifuged, or extracted as necessary. An arbitrary operation such as purification and sterilization may be added as appropriate, and the resulting extract diluted, concentrated and dried may be used as cellobiose lipid.

  The method for recovering or purifying cellobiose lipid from the culture solution of the cellobiose lipid-producing microorganism is not particularly limited, and can be appropriately selected according to the purpose. For example, it can be recovered by centrifuging the culture solution to recover the oil, and extracting and concentrating with an organic solvent such as ethyl acetate.

  The extraction method is not particularly limited, and usually only needs to be in the range of the boiling point of the solvent at normal temperature and normal pressure, and after extraction, using filtration or ion exchange resin, adsorption, decolorization and purification, solution, paste, A gel form or a powder form may be used. Usually, it can be used as it is, but if necessary, further purification treatment such as deodorization and decolorization may be added within a range not affecting its efficacy. As a purification treatment means such as deodorization and decolorization, an activated carbon column or the like may be used, and a normal means generally applied depending on the extracted substance may be arbitrarily selected. If necessary, a cellobiose lipid with high purity can be obtained by purification using a silica gel column.

  As an extraction solvent, use an organic solvent such as water, alcohols, ketones, diethyl ether, dioxane, acetonitrile, esters, xylene, benzene, chloroform, alone or in any combination of two or more kinds. A combination of the respective solvent extracts can also be used.

Cellobiose lipid salt The cellobiose lipid salt of the present invention is one in which the hydrogen atom of the carboxyl group in the cellobiose lipid is replaced by another metal cation or a metal group.

  The cellobiose lipid salt of the present invention is preferably a salt of cellobiose lipid and an alkali metal or alkaline earth metal. By using cellobiose lipid as a salt with an alkali metal or an alkaline earth metal, the solubility in an aqueous solvent is improved and the cellobiose lipid can be dissolved well.

  Examples of the alkali metal constituting the salt with cellobiose lipid include sodium, potassium, lithium and the like, and examples of the alkaline earth metal include calcium, magnesium, beryllium and the like. Among these, alkali metals are preferable, sodium or potassium is more preferable, and sodium is particularly preferable. Cellobiose lipid sodium salt has the advantage of high water solubility and further improved solubility in solvents.

  The method for producing the cellobiose lipid salt of the present invention is not particularly limited. For example, when obtaining a salt of cellobiose lipid and an alkali metal, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used as the cellobiose lipid. Can be obtained by neutralization. As a more specific example, a cellobiose lipid salt can be obtained by the following method. The cellobiose lipid is mixed with water, and while stirring with a stirrer, an arbitrary alkali is added to neutralize the aqueous solution and dissolve the cellobiose lipid. A cellobiose lipid salt can be obtained by lyophilizing an aqueous solution having a final pH of about 7.5. The form of the salt of cellobiose lipid of the present invention may be a solid salt of cellobiose lipid obtained by the above method or the like, or a cellobiose lipid solution (cellobiose neutralized with an alkali before lyophilization) An aqueous solution containing a salt of lipid).

Compositions comprising a salt of cellobiose lipid The composition of the present invention comprises a salt of cellobiose lipid. In the composition of the present invention, the blending amount of the cellobiose lipid salt is not particularly limited, but is usually about 0.1 to 30% by mass, and preferably about 0.5 to 15% by mass.

  Moreover, the composition of this invention can be made into an aqueous composition. That is, the aqueous composition of the present invention includes a cellobiose lipid salt and an aqueous component.

  The aqueous component contained in the aqueous composition of the present invention is not particularly limited as long as it is an aqueous solvent that can dissolve the salt of cellobiose lipid. For example, water or a lower alcohol having 1 to 4 carbon atoms, glycol, etc. in water. Examples thereof include a dissolved or dispersed aqueous solution. The aqueous solvent is a solvent mainly composed of water or a hydrophilic solvent, and preferably does not contain any hydrophobic solvent.

  In the aqueous composition of the present invention, the aqueous component is usually contained in an amount of about 70 to 99.5% by mass, preferably about 85 to 99.5% by mass.

  In addition, the cellobiose lipid salt of the present invention forms an aqueous gel or aqueous sol by incorporating the aqueous component in a system in which the aqueous component is present. Therefore, the aqueous composition of the present invention can be made into a gel or sol composition.

  The blending amount of the cellobiose lipid in the gel-like or sol-like composition of the present invention is not particularly limited, but is preferably about 0.5 to 30% by mass from the viewpoint of forming an aqueous gel, 0.5 to More preferably, it is about 15% by mass.

  The pH of the gel-like or sol-like composition of the present invention is usually adjusted to a range of about 6.0 to 9.0, preferably about 6.5 to 8.0.

Method for Producing Aqueous Gel A method for producing an aqueous gel using the cellobiose lipid salt of the present invention is not particularly limited. For example, an alkaline aqueous solution containing an alkali metal or an alkaline earth metal in preparing a cellobiose lipid salt is used. An aqueous gel can be produced by using a solvent as an aqueous component, dissolving cellobiose lipid while neutralizing with an alkaline aqueous solution, and adjusting the concentration of the salt of cellobiose lipid.

  The reason is not clear, but it has been found that when an aqueous gel is prepared, gelation is promoted by allowing an aqueous solution containing a salt of cellobiose lipid and an aqueous component to stand under low temperature conditions. The temperature at the time of standing is usually about 48 ° C. or less, preferably about 40 ° C. or less, more preferably about 15 ° C. or less, particularly preferably about 10 ° C. or less. . Moreover, it is although it does not specifically limit as time or period to stand still, 6 hours or more are preferable, 24 hours or more are more preferable, and 2 to 4 days are especially preferable.

Use of the cellobiose lipid salt The cellobiose lipid salt of the present invention has a significantly improved solubility in aqueous solvents such as water compared to cellobiose lipid, so the viscosity of an aqueous solvent containing the cellobiose lipid salt is increased. Can be granted. Therefore, the cellobiose lipid salt of the present invention can be used as a thickener, a gelling agent, a viscosity modifier and the like.

  Furthermore, the cellobiose lipid salt self-assembles in the system in which the aqueous component is present and takes up the aqueous component to form an aqueous gel or aqueous sol. Since the gel composition containing the salt of cellobiose lipid and the aqueous component is aqueous, an appropriate viscosity can be imparted to the compounded composition of the gel composition. On the other hand, when cellobiose lipid that does not form a salt is used, gelation does not occur and cellobiose lipid precipitates and separates from the aqueous component.

  Moreover, the composition containing the salt of cellobiose lipid of the present invention can be used by blending it in cosmetics, quasi-drugs, medical supplies, hygiene products, pharmaceutical products, food and drinks, and the like.

  Cosmetics, quasi-drugs, medical supplies, hygiene products, and pharmaceuticals include, for example, basic and cosmetic preparations such as internal and external pharmaceutical preparations, lotions, emulsions, creams, ointments, lotions, oils, packs, facial cleansers and skins. Hair care cosmetics such as cleaning agents, shampoos, rinses, hair treatments, hair creams, pomades, hair sprays, hair styling agents, permanents, hair nickings, hair dyes, hair growth and hair nourishing agents, foundations, white powder, funny hair, lipsticks, blushers, Makeup cosmetics such as eye shadow, eyeliner, mascara, eyebrows, eyelashes, cosmetics for finishing such as nail polish, perfumes, bath preparations, toothpaste, fresheners in mouth, gargle, liquid odor and deodorant Examples include inhibitors, sanitary products, sanitary cotton, and wet tissue. The aqueous gel composition of the present invention can also be used by blending it with an ointment or a poultice.

  As the food and drink, for example, soft drinks, carbonated drinks, nutritional drinks, fruit drinks, lactic acid drinks and other drinks, ice cream, ice sherbet, shaved ice and other frozen desserts, buckwheat, udon, harusame, gyoza skin, Chinese noodles, instant noodles and other noodles, rice cakes, candy, gum, chocolate, tablet confectionery, snack confectionery, biscuits, jelly, jam, cream, baked confectionery, bakery confectionery, crab, salmon, clams, tuna, sardines, shrimp , Bonito, mackerel, whales, oysters, saury, squid, red scallop, scallop, abalone, sea urchin, salmon roe, tofubushi and other marine products, fishery products such as kamaboko, ham and sausage, dairy products such as processed milk and fermented milk , Salad oil, tempura oil, margarine, mayonnaise, shortening, whipped cream, dressing, etc. Seasonings such as foods, sauces, sauces, curry, stew, oyakodon, rice bowls, miscellaneous cooking, Chinese rice bowls, bonito, tempura, eel rice, hayashi rice, oden, mabodorf, beef bowl, meat sauce, egg soup, omelet rice, dumplings, Examples include retort pouch foods such as shumai, hamburger and meatballs, various forms of health and nutritional supplements, health functional foods, tablets, capsules, drinks, troches and the like.

  When the composition of the present invention is blended in cosmetics, its form is not particularly limited, and it may take any state such as solid, liquid, paste, jelly, and powder. In particular, when the aqueous composition of the present invention is blended in cosmetics, not only can an appropriate viscosity be imparted, but a refreshing feeling can be imparted and cosmetics excellent in usability can be provided. .

  Moreover, the gel-like composition of the present invention forms an aqueous gel having a characteristic of transition from a gel state to a sol state at a relatively small strain and a relatively mild temperature. Therefore, cosmetics formulated with the gel composition of the present invention are in a gel state at the time of storage, but when applied to the skin, they are easily dissolved in a sol state by stretching with the temperature of the skin surface and the fingers and palms. Therefore, the conformability and spreadability on the skin are good, and the above-mentioned excellent usability is exhibited.

  When the composition of the present invention is blended into a quasi-drug, medical product, hygiene product, pharmaceutical product, etc., its dosage form is not particularly limited, and ampoules, capsules, powders, granules, pills, tablets, solids, A variety of liquids, gels, bubbles, emulsions, creams, ointments, sheets, mousses, bathing agents and the like can be used. In addition, due to the characteristics of the aqueous gel formed by the salt of cellobiose lipid, when the aqueous composition of the present invention is blended, the quasi-drug and medical product that can easily release the active ingredient contained in the gel Sanitary supplies, medicines, etc. can be provided. The gel composition of the present invention can also be used as a taste-masking agent that contains a drug or the like and can reduce discomfort such as bitterness and astringency of the active ingredient of the drug.

  The blending amount of the composition of the present invention into cosmetics, quasi-drugs, medical products, hygiene products, pharmaceutical products, foods and drinks, etc. is determined by the degree of absorption, the level of action, the product form, the frequency of use, etc. Although not intended, for example, when blended into cosmetics, 0.001 mass% to 10 mass%, preferably 0.01 mass% to 5.0 mass%, more preferably 0.1 mass% to 1. mass%. What is necessary is just to mix | blend so that it may become 0 mass%. When blended in cosmetics or pharmaceuticals such as liquid preparations or creams, emulsions, lotions, lotions, ointments and the like, which are directly applied to human skin, 0.001% by mass to 10% by mass, preferably 0.00%. What is necessary is just to mix | blend so that it may become 01 mass%-5.0 mass%, More preferably, 0.1 mass%-1.0 mass%.

  In addition, cosmetics, quasi-drugs, medical supplies, hygiene products, pharmaceuticals, etc. containing the composition of the present invention are included in the cosmetics, quasi-drugs, if necessary, as long as the effects of the present invention are not impaired. Any components such as components and additives used in medical supplies, hygiene products, pharmaceuticals, and the like can be used in combination.

  The various uses of the composition of the present invention are preferably applied to humans, but can be applied to animals other than humans as long as the respective effects can be expected.

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

Example 1: Production of cellobiose lipid (CL) using Cryptococcus humicola Cryptococcus humicola NBRC 10251 was inoculated into 50 mL of a seed medium having the following composition, and then cultured at 27 ° C overnight. Inoculum culture was performed.
(Seed medium composition)
Glucose 100g / L
Sodium nitrate 30g / L
Magnesium sulfate heptahydrate 3g / L
Potassium dihydrogen phosphate 3g / L
Yeast extract 1g / L

100 mL of the inoculum culture solution obtained by the above inoculum culture is inoculated into 6 L of production medium having the following composition, and cultured for 6 days under the conditions of 27 ° C., 530 rpm (stirring rotation), 3 L / min (Air). went.
(Production medium composition)
Glucose 50g / L
Sodium nitrate 3g / L
Magnesium sulfate heptahydrate 0.5g / L
Potassium dihydrogen phosphate 0.02g / L
Dipotassium hydrogen phosphate 0.5g / L
Yeast extract 8g / L

  Cellobiose lipid was extracted from the main culture obtained by the main culture by the following method. First, after collecting the main culture by centrifugation (7500 rpm, 20 minutes), a solution obtained by mixing an equal amount of ethyl acetate and acetone in a ratio of 4: 1 to the obtained cells was added and stirred, A supernatant was obtained. Next, the obtained supernatant was dried by an evaporator to obtain a powder. Thereafter, in order to remove lipid impurities from the obtained powder, hexane (300 g) was added to the powder and stirred, followed by glass filter filtration and evaporation in order to remove hexane and obtain cellobiose lipid. It was.

Example 2: Manufacture of cellobiose lipid using Ustilago esculenta (Ustilago esculenta) After inoculation of Ustilago esculenta (Ustilago esculenta NBRC 9887) in 50 mL of a seed medium having the following composition, the seed culture is cultured overnight at 27 ° C. went.
(Seed medium composition)
Glucose 50g / L
Sodium nitrate 3g / L
Magnesium sulfate heptahydrate 0.5g / L
Potassium dihydrogen phosphate 0.02g / L
Dipotassium hydrogen phosphate 0.5g / L
Yeast extract 8g / L

100 mL of the inoculum culture solution obtained by the above inoculum culture is inoculated into 6 L of production medium having the following composition, and cultured for 6 days under the conditions of 27 ° C., 530 rpm (stirring rotation), 3 L / min (Air). went.
(Production medium composition)
Glucose 50g / L
Sodium nitrate 3g / L
Magnesium sulfate heptahydrate 0.5g / L
Potassium dihydrogen phosphate 0.025g / L
Dipotassium hydrogen phosphate 0.5g / L
Yeast extract 8g / L

  Cellobiose lipids were extracted from the main culture obtained by the main culture by the following method. First, after collecting the main culture by centrifugation (7500 rpm, 20 minutes), a solution obtained by mixing an equal amount of ethyl acetate and acetone in a ratio of 4: 1 to the obtained cells was added and stirred, A supernatant was obtained. Next, the obtained supernatant was dried by an evaporator to obtain a powder. Thereafter, in order to remove lipid impurities from the obtained powder, hexane (300 g) was added to the powder and stirred, followed by glass filter filtration and evaporation in order to remove hexane and obtain cellobiose lipid. It was.

Example 3: Examination of solubility of cellobiose lipid in water and preparation of aqueous gel The cellobiose lipid obtained in Example 1 was added to distilled water while neutralizing with sodium hydroxide. Aqueous solutions (pH 7.6) containing cellobiose lipid salts at the stated concentrations were prepared.

  For comparison, the cellobiose lipid obtained in Example 1 was added to distilled water without neutralizing with sodium hydroxide, and an aqueous solution (pH 7.) containing cellobiose lipid at the concentrations shown in Table 1 below. 6) were prepared respectively.

  Each aqueous solution prepared by the above method was allowed to stand at 4 ° C. for 4 days, and then the presence or absence of gelation of each sample was visually confirmed. A sample in which gelation was confirmed was indicated by ◯, a sample in which gelation was not confirmed was indicated by Δ, and a sample in which precipitation was confirmed without dissolution in the aqueous solution was indicated by ×. In addition, the presence or absence of gelation was judged that the sample bottle containing the aqueous solution was inverted and the aqueous solution did not sag and gelled.

  The above results are shown in Table 1 below.

  As is clear from the results in Table 1, in the samples not subjected to the neutralization treatment with sodium hydroxide (samples A to J), the cellobiose lipid was not dissolved in the aqueous solution and a precipitate was formed. On the other hand, in the samples (samples 1 to 10) subjected to the neutralization treatment with sodium hydroxide, it was confirmed that the salt of cellobiose lipid was dissolved in the aqueous solution. Especially, gelation was confirmed about the sample (samples 3-10) whose density | concentration of the salt of cellobiose lipid is 0.5 weight% or more.

Example 4: Measurement of Viscoelasticity of Aqueous Gel Of the samples in which gelation was confirmed in Example 3 above, a rheometer manufactured by Anton Paar (MCR302) was used with a cellobiose lipid salt concentration of 2% by weight (sample 6). ) To measure viscoelasticity by the following method. For the measurement of viscoelasticity, a cone plate (CP25.2) having a diameter of 24.98 mm and an angle of 1.994 ° was used.

4-1 Measurement of Angular Frequency Dependence First, the angular frequency (ω) dependence of the storage elastic modulus (G ′) and loss elastic modulus (G ″) of the sample at 25 ° C. was measured. The strain (γ) during measurement was fixed at 1%. The results are shown in FIG.

  As is apparent from the results of FIG. 1, the storage elastic modulus (G ′) is larger than the loss elastic modulus (G ″) at any angular frequency, and thus used for measurement. It was confirmed that the sample was in a gel state.

  Further, from the values of the storage elastic modulus (G ′) and loss elastic modulus (G ″) of the sample, it was confirmed that the sample used for the measurement was a relatively soft gel.

4-2: Measurement of strain dependency Next, the strain (γ) dependency of the storage elastic modulus (G ′) and loss elastic modulus (G ″) of the sample at 25 ° C. was measured. The angular frequency (ω) at the time of measurement was fixed at 1 (1 / S). The results are shown in FIG.

  As apparent from the results of FIG. 2, in the low strain region, the value of the storage elastic modulus (G ′) is larger than the value of the loss elastic modulus (G ″), and the sample maintains a gel state. Was confirmed. Furthermore, when the strain was 3.5% or more, it was confirmed that the sample transitioned from the gel state to the sol state.

  From these facts, the sample used for the measurement transitions from the gel state to the sol state with a relatively small strain of 3.5%. Therefore, when the gel composition of the present invention is applied to the skin, the gel It is considered that the active ingredient encapsulated in can be easily released.

4-3: Measurement of temperature dependence Furthermore, the temperature dependence of the storage elastic modulus (G ′) and loss elastic modulus (G ″) of the sample was measured. The strain (γ) during measurement was fixed at 1%, and the angular frequency (ω) was fixed at 1 (1 / S). The results are shown in FIG.

  As apparent from the results of FIG. 3, in the low temperature region, the value of the storage elastic modulus (G ′) is larger than the value of the loss elastic modulus (G ″), and the sample can maintain a gel state. It could be confirmed. Furthermore, the storage elastic modulus (G ′) and the loss elastic modulus (G ″) begin to rapidly decrease from about 40 ° C. near the living body temperature, and the storage elastic modulus (G ′) is below the detection lower limit of the device near 48 ° C. Thus, it was confirmed that the sample transitioned from the gel state to the sol state at around 48 ° C.

  From these facts, when preparing an aqueous gel containing a cellobiose lipid salt, it is considered desirable to cool the sample at a temperature of about 48 ° C. or lower after dissolving the cellobiose lipid salt.

  In addition, since the sol-gel transition temperature of a sample having a cellobiose lipid salt concentration of 2% by mass is around 48 ° C., the sol-gel transition temperature is adjusted to the biological temperature by appropriately adjusting the cellobiose lipid salt concentration. It is considered that the temperature can be set to a nearby temperature. The transition from the gel state to the sol state near the living body temperature is such that the active ingredient contained in the gel can be easily released when the gel-like composition of the present invention is applied to the skin. Conceivable.

  The cellobiose lipid salt of the present invention can be suitably used as an additive for cosmetics, pharmaceuticals, foods and drinks, and the like. Furthermore, since cellobiose lipid is derived from microorganisms, it is safe, can be mass-produced at low cost, and can sufficiently withstand long-term use, so it is expected to make a significant contribution to the industry.

Claims (6)

An aqueous gel or sol composition comprising a salt of cellobiose lipid. The composition according to claim 1, wherein the salt is an alkali metal salt or an alkaline earth metal salt. The composition according to claim 2, wherein the alkali metal salt is a sodium salt or a potassium salt. The composition according to any one of claims 1 to 3, comprising 0.1 to 30% by mass of a salt of cellobiose lipid. A thickener for aqueous compositions comprising a salt of cellobiose lipid. A method for producing an aqueous gel, comprising a step of allowing an aqueous solution containing a cellobiose lipid salt to stand at 48 ° C or lower.

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