JP7730280B2 - Isovaleric acid odor suppressant - Google Patents

Description

The present invention relates to an isovaleric acid odor suppressant containing a specific fragrance as an active ingredient.

Our living environment is home to a large number of malodorous molecules with different polarities and molecular weights. A variety of deodorizing methods have been developed to eliminate these diverse malodorous molecules. Generally, deodorizing methods can be broadly divided into biological, chemical, physical, and sensory methods. Among malodorous molecules, short-chain fatty acids, including isovaleric acid, can be deodorized chemically, namely through a neutralization reaction.

However, these malodorous substances often have a low threshold, making it difficult to deodorize them to a concentration that cannot be detected using chemical deodorization methods alone. Therefore, sensory deodorization is often used in combination to effectively deodorize. Sensory deodorization mainly includes (1) a method using a fragrance in excess of the malodor, known as masking deodorization; (2) a method using a fragrance with strong characteristics different from the malodor, known as pairing deodorization; (3) a method of deodorizing by using a fragrance that responds to the olfactory receptors to which malodors respond, causing adaptation; (4) a method of deodorizing by suppressing the response of the olfactory receptors to which malodors respond; and (5) a method of deodorizing by modulating or blocking signals from olfactory cells.

Isovaleric acid (3-methylbutanoic acid) is a naturally occurring short-chain fatty acid and one of the substances that causes body odor due to sweat and sebum, with a low threshold. Several substances have been disclosed as chemical deodorizers for isovaleric acid. For example, Patent Document 1 discloses a fragrance composition for modulating the odor of fatty acids having 2 to 6 carbon atoms, such as isovaleric acid, which contains one or more fragrances selected from hexanol, cis-3-hexenol, linalool, tetrahydrolinalool, geraniol, and ethyl 2-tert-butylcyclohexyl carbonate.

Patent Document 2 discloses 3-(3-isopropyl-phenyl)-butyraldehyde, Patent Document 3 discloses one or more compounds selected from the group consisting of 2,4,6-trimethyl-3-cyclohexene-1-carboxaldehyde, 3,5,6-trimethyl-3-cyclohexene-1-carboxaldehyde, 3-(4-tert-butylphenyl)propanal, and 3-(3-isopropyl-phenyl)-butyraldehyde, Patent Document 4 discloses 1,4-cineole or 1,8-cineole, Patent Document 5 discloses one or more compounds selected from the group consisting of 2-methylbutyric acid, 2-ethylbutyric acid, 2-ethylvaleric acid, 2-ethylhexanoic acid, 2-phenylbutyric acid, and 2-isopropylhexanoic acid, and Patent Document 6 discloses at least one compound selected from the group consisting of acetylcedrene, γ-methylionone, and galaxolide.

Japanese Patent Application Laid-Open No. 2007-31605 Japanese Patent Application Laid-Open No. 2016-187557 Japanese Patent Application Laid-Open No. 2015-091802 Japanese Patent Application Laid-Open No. 2017-113354 Japanese Patent Application Laid-Open No. 2018-121865 Japanese Patent Application Laid-Open No. 2020-111555

Therefore, the object of the present invention is to provide a novel isovaleric acid odor suppressant, etc.

The olfactory receptors that recognize odor molecules such as malodors are complex, and known fragrance ingredients do not necessarily suppress malodors such as isovaleric acid odor; in fact, they may even increase the malodor. The inventors discovered that specific fragrance ingredients suppress the isovaleric acid odor, leading to the completion of this invention.

That is, the present invention provides an isovaleric acid odor suppressant containing one or more active ingredients selected from the group consisting of gamma-undecalactone, strawberry aldehyde, ethylene brassylate, jasmal, 3-methyl-5-phenyl-1-pentanol, alpha-damascone, nerol, ethyl acetate, fenchol, styrallyl acetate, 4-methyl-3-decen-5-ol, rifarom, terpineol, and furhydral.

The present invention also provides a method for suppressing isovaleric acid odor, which includes a step of contacting the isovaleric acid odor suppressant with isovaleric acid.

The isovaleric acid odor suppressant provided by the present invention exhibits an isovaleric acid odor suppression effect that is equal to or far superior to existing products.

The present invention uses one or more active ingredients selected from the group consisting of gamma-undecalactone, strawberry aldehyde, ethylene brassylate, jasmal, 3-methyl-5-phenyl-1-pentanol, α-damascone, nerol, ethyl acetate, fenchol, styrallyl acetate, 4-methyl-3-decen-5-ol, rifaline, terpineol, and furhydral.

Of the above compounds, the following compounds are preferred: γ-undecalactone, strawberry aldehyde, ethylene brassylate, ethyl acetate, fenchol, jasmal, styrallyl acetate, α-damascone, 3-methyl-5-phenyl-1-pentanol, nerol, and 4-methyl-3-decen-5-ol. Among these, γ-undecalactone, strawberry aldehyde, ethylene brassylate, jasmal, and nerol are more preferred because they have low fragrance strength. Of these compounds, γ-undecalactone and jasmal are more preferred.

Each compound may be used alone, or two or more may be used in combination, provided that the isovaleric acid odor suppressing effect is not impaired. Furthermore, these compounds may be used in combination with other fragrance ingredients to prepare a blended fragrance. Such other fragrance ingredients are not particularly limited as long as they do not impair the isovaleric acid odor suppressing effect. Examples of such fragrance ingredients include animal fragrances such as musk, spirit cat fragrance, and dragon's laurel fragrance, as well as abies oil, aquifolia oil, almond oil, angelica root oil, peper oil, bergamot oil, perch oil, bois rose oil, kayabuchi oil, gananga oil, capsicum oil, caraway oil, cardamom oil, cassia oil, celery oil, cinnamon oil, citronella oil, cognac oil, and coriaceae oil. Examples of suitable fragrances include plant-based fragrances such as under oil, cumin oil, camphor oil, basil oil, estgolan oil, eucalyptus oil, fennel oil, garlic oil, ginger oil, grapefruit oil, hop oil, lemon oil, lemongrass oil, nutmeg oil, mandarin oil, peppermint oil, orange oil, sage oil, star anise oil, turpentine oil, rosemary oil, eucalyptus oil, anise oil, lavender oil, cumin oil, cinnamon oil, and hiba oil. In addition, artificial fragrances such as synthetic fragrances or extracted fragrances can also be used as fragrances. Examples of such fragrances include hydrocarbon fragrances such as pinene and limonene; alcohol-based fragrances such as linalool, geraniol, citronellol, menthol, borneol, benzyl alcohol, anise alcohol, and β-phenethyl alcohol; phenol-based fragrances such as anethole and eugenol; aldehyde-based fragrances such as n-butyraldehyde, isobutyraldehyde, hexylaldehyde, citral, citronellal, benzaldehyde, and cinnamic aldehyde; ketone-based fragrances such as carvone, menthone, camphor, acetophenone, and ionone; lactone-based fragrances such as γ-butyrolactone, coumarin, and cineole; and ester-based fragrances such as octyl acetate, benzyl acetate, cinnamyl acetate, butyl propionate, and methyl benzoate.

The isovaleric acid odor inhibitor can be used to eliminate or neutralize the isovaleric acid odor contained in sweat, body odor, socks, etc. The isovaleric acid odor inhibitor can be applied directly to the source of the isovaleric acid odor. If the isovaleric acid odor is caused by bacterial growth, in addition to applying the isovaleric acid odor inhibitor, an antibacterial treatment to inhibit bacterial growth may also be performed.

The isovaleric acid odor inhibitor is expected to be incorporated into various deodorants, various air fresheners, body or facial cleansers, laundry detergents, fabric softeners, cosmetics, and fragrance products. The isovaleric acid odor inhibitor is incorporated in a volatile state, including, but not limited to, liquid formulations, sheet-like formulations supported on a carrier such as fiber, gel formulations, etc.

Examples include oil-type deodorants in which isovaleric acid odor suppressants or compound fragrances prepared by blending them directly or in a suitable volatile organic solvent and then volatilizing them using a volatile medium; water-based deodorants in which isovaleric acid odor suppressants or compound fragrances prepared by blending them are dissolved in water using a surfactant or the like to form an aqueous solution, which is then volatilized using a volatile medium; gel-type deodorants in which these are gelled using a gelling agent; and deodorants in which they are absorbed into a highly water-absorbent resin.

Volatile organic solvents include, but are not limited to, volatile alcohols and volatile glycol ethers. Volatile alcohols include lower alcohols such as methanol, ethanol, 1-propanol, and 2-propanol. Volatile glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol dimethyl ether, propylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, butylene glycol monomethyl ether, 3-methoxy-1-butanol, and 3-methoxy-3-methyl-1-butanol.

The surfactant may be a nonionic surfactant, anionic surfactant, cationic surfactant, or amphoteric surfactant, either singly or in combination.
The nonionic surfactant is not particularly limited, but examples thereof include polyoxyethylene alkyl ethers, polyoxyalkylene alkyl ethers, polyoxyethylene hydrogenated castor oil ethers, polyoxyethylene fatty acid esters, polyoxyethylene alkylphenyl ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, sucrose fatty acid esters, glycerin fatty acid esters, polyoxyethylene polyoxypropylene block polymers, polyoxyethylene alkylamine ethers, fatty acid alkanolamides, tertiary amine oxides, etc. The polyoxyethylene alkyl ethers have a polyoxyethylene chain length of 3 to 18, preferably 7 to 12, and the alkyl chain may be either linear or branched, with an alkyl chain length of 8 to 22, preferably 12 to 14. Examples of the fatty acid alkanolamide include monoethanolamide and diethanolamide of coconut oil fatty acid, stearic acid, and lauric acid, and examples of the tertiary amine oxide include lauryl dimethylamine oxide, coconut oil fatty acid dimethylamine oxide, lauroylaminopropyl dimethylamine oxide, octyl dimethylamine oxide, and myristyl dimethylamine oxide.

Examples of anionic surfactants that can be used alone or in combination of two or more include higher fatty acid soap, soap base, metallic soap, N-acyl-L-glutamic acid triethanolamine, N-acyl-L-glutamic acid sodium, sodium alkyl sulfate, sodium alkyl sulfonate, polyoxyethylene alkyl ether sodium sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate, coconut oil fatty acid sodium methyl taurate (N-cocoyl-N-methyl taurate sodium), triethanolamine lauryl sulfate, sodium lauryl sulfate, sodium lauroyl sarcosine, lauroyl methyl β-alanine sodium solution, and lauroyl methyl taurate sodium.

Cationic surfactants that can be used include, but are not limited to, lanolin fatty acid aminopropylethyldimethylammonium ethyl sulfate, alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, distearyldimethylammonium chloride, stearyldimethylbenzylammonium chloride, stearyltrimethylammonium chloride, benzalkonium chloride, and benzethonium chloride, and can be used alone or in combination with two or more of these.

As amphoteric surfactants, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, alkyldiaminoethylglycine hydrochloride solution, lauryldimethylaminoacetic acid betaine, etc. can be used alone or in combination with two or more of them.

Examples of gelling agents include conventionally known agents such as carrageenan, gellan gum, agar, gelatin, guar gum, pectin, locust bean gum, xanthan gum, tamarind gum, sodium alginate, isobutylene-maleic anhydride copolymer, and cellulose derivatives such as carboxymethyl cellulose.

Water-absorbent resins include, but are not limited to, those containing polyacrylic acid or its salts, such as crosslinked polyacrylates, partially neutralized polyacrylates, crosslinked acrylic acid and/or its salts-acrylamide copolymers, crosslinked isobutylene-maleic anhydride copolymers, hydrolyzed starch-acrylonitrile graft copolymers, (partially) neutralized starch-acrylic acid ester copolymers, saponified and partially saponified vinyl acetate-acrylic acid ester copolymers, hydrolyzed acrylonitrile copolymers or acrylamide copolymers, and modified polyvinyl alcohols.

Isovaleric acid odor suppressants may contain other ingredients with deodorizing effects, or any ingredients used in deodorants or deodorizers, as long as they do not impair the effectiveness of the active ingredient, depending on the purpose. Any known deodorizing ingredients can be used as such other ingredients with deodorizing effects. Examples include active deodorizing ingredients extracted from various parts of plants, such as leaves, petioles, fruits, stems, roots, and bark (e.g., green tea extract); organic acids such as lactic acid, gluconic acid, succinic acid, glutaric acid, adipic acid, malic acid, tartaric acid, maleic acid, fumaric acid, itaconic acid, citric acid, benzoic acid, and salicylic acid; various amino acids and their salts; glyoxal; oxidizing agents; flavonoids; catechins; polyphenols; porous substances such as activated carbon and zeolites; inclusion agents such as cyclodextrins; photocatalysts; and various masking agents.

Examples of optional ingredients used in deodorants and anti-odor agents include fragrances, powdered ingredients, liquid oils and fats, solid oils and fats, waxes, hydrocarbons, plant extracts, herbal ingredients, higher alcohols, lower alcohols, esters, long-chain fatty acids, surfactants (nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, etc.), sterols, polyhydric alcohols, humectants, water-soluble polymeric compounds, thickeners, film-forming agents, bactericides, preservatives, UV absorbers, fixatives, cooling agents, warming agents, irritants, sequestering agents, sugars, amino acids, organic amines, synthetic resin emulsions, pH adjusters, antioxidants, antioxidant aids, oils, powders, capsules, chelating agents, inorganic salts, organic salt pigments, thickeners, bactericides, preservatives, antifungal agents, colorants, antifoaming agents, bulking agents, modulators, organic acids, polymers, polymer dispersants, enzymes, and enzyme stabilizers.

In a second embodiment, a method for suppressing isovaleric acid odor is provided, which includes a step of contacting an isovaleric acid odor suppressor with isovaleric acid.

Possible sources of isovaleric acid odor include clothing such as socks where bacteria that produce isovaleric acid grow, as well as livestock farms, rendering plants, starch factories, etc. However, as used in this specification, sources to which isovaleric acid odor inhibitors are directly applied do not include parts of the human body.

Contact can also be achieved by applying an isovaleric acid odor inhibitor to the source of isovaleric acid or the isovaleric acid odor. Application methods include sprinkling, spraying, and painting, and can be determined by those skilled in the art depending on the dosage form of the isovaleric acid odor inhibitor. It can also be combined with known isovaleric acid odor suppression methods. For example, if the isovaleric acid odor is caused by bacterial growth, in addition to applying an isovaleric acid odor inhibitor, an antibacterial treatment to suppress bacterial growth can be performed.

The timing of application is not particularly limited, and can be carried out as soon as the isovaleric acid odor is perceived. As a preventative measure, an isovaleric acid odor inhibitor may be applied in advance to areas where the isovaleric acid odor is expected to occur.

The present invention will be explained in more detail below using examples. However, the present invention is not limited to the description of the following examples.

<Sensory test>
(Test sample)
The following test samples were used to test the deodorizing effect on the odor of isovaleric acid.

(Preparation of Masterbatch)
Isovaleric acid was dissolved in dimethyl sulfoxide (DMSO) to prepare solutions (0.001 ppm, 0.01 ppm, 0.1 ppm, 1 ppm, 10 ppm, 100 ppm). Five grams of each solution was impregnated into pleated filter paper (185 mm diameter) and placed in a 500 ml beaker. The beaker was then sealed in a 10-liter bag, filled with odorless air, and left to stand at room temperature for 24 hours to prepare six types of masterbatch bags.

(Preparation of malodorous bags)
The amounts of air shown in Table 2 were taken from the six types of master batch bags using a syringe and injected into 3 liter odor bags filled with odorless air to prepare odor bags 1 to 8.

(Preparation of scented bags)
1 g of each of the fragrances in Table 1 was soaked in a pleated filter paper (diameter 90 mm) and placed in a 500 ml beaker. The beaker was sealed in a 10 liter bag, filled with odorless air, and left to stand at 25°C for 30 minutes to prepare a fragrance bag.

(Preparation of sample bags)
Another set of the malodor bags 1 to 8 was prepared, and 200 ml of air was taken from the scent bag and poured into each set, creating sample bags 1 to 8 in order.

(Pleasantness/unpleasantness of fragrance, preference)
200 ml of each fragrance was taken from the fragrance pouch and filled into a 3-liter bag with odorless air. The pleasantness or unpleasantness and intensity of each fragrance were evaluated according to the following criteria. The values shown are the average scores of four panelists who passed the olfactory test (T&T olfactometer method) in the Odor Judgement Test and were confirmed to have normal sense of smell. The results are shown in Table 3.

(pleasantness/unpleasantness)
-4: Extremely uncomfortable -3: Very uncomfortable -2: Uncomfortable -1: Slightly uncomfortable 0: Neither comfortable nor uncomfortable +1: Slightly comfortable +2: Comfortable +3: Very comfortable +4: Extremely comfortable

(strength)
-3: Very weak -2: Weak -1: Slightly weak 0: Just right +1: Slightly strong +2: Strong +3: Very strong

(Perception test of malodor caused by fragrance)
The panelists were asked to smell the malodorous bags prepared above in order of increasing concentration, and those that could be determined to have the odor of isovaleric acid were marked with an ◯, and those that could not be determined to have the odor of isovaleric acid were marked with an ×. The number of the malodorous bag that could be recognized was taken as the threshold value of the odor of isovaleric acid.

Next, the panelists were asked to smell the sample bags containing the fragrance in the same order, starting with the malodor concentration. Those who were able to identify the odor as isovaleric acid were given an ◯, and those who were not were given an ×. The number of the malodor-recognized bag was taken as the odor threshold of isovaleric acid in the fragrance-mixed air. The value is the average of the four panelists. The results are shown in Table 3. If the threshold when the fragrance was added to a similar bag was higher than the concentration (threshold) felt when smelling the malodor alone, it was determined that the fragrance was contributing to deodorization (recognition of malodor). Specifically, a score of 2 or more higher than the threshold for the malodor alone was given a ◎, a score of 1 or more higher was given an ◯, a score of less than 1 (0 or higher) was given a △, and a score of less than 0 was given an ×. The malodor-only bag was used as a control, so its odor suppression function was not evaluated.

These results show that fragrances Nos. 1 to 14 all make the odor of isovaleric acid less noticeable. In particular, fragrances Nos. 4 to 6, 8, and 10 to 14, which had different threshold values, significantly lessened the odor of isovaleric acid compared to geraniol, a known isovaleric acid odor suppressor. Furthermore, while strong fragrances have limited uses, jasmal, strawberry aldehyde, ethylene brassylate, gamma-undecalactone, and nerol, which have low strength and high odor suppression effects, are particularly desirable isovaleric acid odor suppressors and are expected to be used in a variety of applications.

Claims (4)

An isovaleric acid odor suppressant containing fenchol and/or rifarom as active ingredients. The isovaleric acid odor suppressant according to claim 1 further contains, as an active ingredient, one or more selected from the group consisting of gamma-undecalactone, strawberry aldehyde, ethylene brassylate, jasmal, alpha-damascone, nerol, ethyl acetate, styrallyl acetate, 4-methyl-3-decen-5-ol, terpineol, and furhydral. 3. The isovaleric acid odor suppressant according to claim 1, wherein the active ingredient is fenchol . A method for suppressing isovaleric acid odor, comprising a step of contacting the isovaleric acid odor suppressant described in any one of claims 1 to 3 with isovaleric acid.