Method for evaluating residuality of fragrance compound

Abstract

To provide a new residuality evaluation method which is a simple method and hardly causes variations in evaluation of various perfume compounds.SOLUTION: The method of the present invention is a method for evaluating the residuality of a flavor and / or fragrance compound, comprising the steps of: (a) bringing a liquid containing a first flavor and / or fragrance compound into contact with an electrode surface of a QCM apparatus; and (b) measuring a change in frequency of a quartz crystal resonator due to adsorption of the first flavor and / or fragrance compound on the electrode surface, wherein in the step (a), the electrode surface of the QCM apparatus contains a constituent of an object to be evaluated.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for evaluating the persistence of a fragrance compound, and more specifically, to a method for evaluating the likelihood of a fragrance compound remaining on an object to be evaluated, such as a towel or hair, when the fragrance compound comes into contact with the object. [Background technology]

[0002] Fragrance compounds are added to cosmetics such as shampoos, conditioners, detergents, and fabric softeners. After using these cosmetics on evaluation objects such as towels and hair, the remaining rate of the fragrance compounds contained in the cosmetics can be determined. Fragrance compounds that remain on the evaluation object for a long time after use can maintain their fragrance for a long time.

[0003] A conventional measurement method for evaluating the residual rate of fragrance compounds on towels includes the following steps: immersing the towels in an aqueous solution of a certain concentration of a fragrance; squeezing the aqueous solution out of the soaked towels until they reach a specific weight; extracting the fragrance compounds remaining in the squeezed towels with a solvent; and analyzing and quantifying the extracted fragrance compounds by gas chromatography.

[0004] Incidentally, an identification device and an identification method for identifying odor components using the quartz crystal microbalance (QCM) method are known from Patent Document 1. Also, an odor sensor that can use the QCM method is known from Patent Document 2. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-061391 [Patent Document 2] International Publication No. 2021 / 132639 Summary of the Invention [Problem to be solved by the invention]

[0006] Conventional methods for assessing the residual rate of fragrance compounds are very time-consuming, and it has been found that, for some types of fragrance compounds, the residual rate assessments are inconsistent and / or inappropriate.

[0007] Therefore, an object of the present invention is to provide a novel, simple method for evaluating the persistence of various fragrance compounds, which is less likely to cause variations in evaluation results. [Means for solving the problem]

[0008] The present inventors have found that the above problems can be solved by the present invention having the following aspects. <<Aspect 1>> 1. A method for evaluating the persistence of fragrance compounds, comprising the steps of: (a) contacting a liquid containing a first fragrance compound with an electrode surface of a QCM device; (b) measuring a change in the frequency of a quartz crystal oscillator caused by the first flavor compound being adsorbed onto the electrode surface; Here, in the step (a), the electrode surface of the QCM device contains a constituent component of the evaluation target. <<Aspect 2>> The method of embodiment 1, further comprising the steps of: (c) contacting a liquid containing a second fragrance compound with the electrode surface of the QCM device; (d) measuring a change in the frequency of the quartz crystal oscillator due to the attachment of the second fragrance compound; (e) comparing the frequency change caused by the second fragrance compound with the frequency change caused by the first fragrance compound. Aspect 3 3. The method of claim 2, comprising performing the following steps for each of a plurality of fragrance compounds different from the first fragrance compound and the second fragrance compound: (f) contacting the liquid containing the fragrance compound with the electrode surface of the QCM device; (g) measuring a change in the frequency of the quartz crystal oscillator due to the attachment of the fragrance compound; (h) comparing the frequency change caused by the fragrance compound with the frequency changes caused by the first fragrance compound and the second fragrance compound. Aspect 4 measuring the residual ratio of the first, second and / or multiple fragrance compounds to the evaluation object; creating a scatter diagram in which the frequency change obtained by the method according to aspect 3 and the survival rate are plotted; When the scatter plot was fitted with a linear regression model, the coefficient of determination (R 2 ) is 0.90 or more, and creating a regression line by selecting the plots; measuring said frequency shift for additional fragrance compounds and estimating said survival rate from said regression line; Here, the survival rate is measured by a method including the following steps: a step of contacting a fragrance compound to be measured with a component of the object to be evaluated; a step of extracting the aroma compound to be measured from the constituent components of the evaluation object with a solvent to obtain an aroma extract; a step of distilling the aroma extract to remove non-volatile components from the aroma extract, thereby obtaining an aroma concentrate; Calculating the survival rate defined by the following formula: Survival rate [%]=A / B×100 (A: Amount of the fragrance compound to be measured contained in the fragrance concentrate B: initial amount of the fragrance compound to be measured). Aspect 5 The method according to embodiment 4, further comprising the step of correcting the survival rate to a survival rate on the regression line for plots not selected in the step of creating the regression line. Aspect 6 2. The method of claim 1, wherein the liquid comprising the fragrance compound is a water-based solution. [Effects of the Invention]

[0009] According to the present invention, a novel residual evaluation method can be provided that can be applied to a variety of evaluation objects and is less likely to cause variations in evaluation of various fragrance compounds. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1A shows a graph in which a straight line was fitted using all of the data obtained in Experiment 1 of the Example. [Figure 1B] FIG. 1B shows a graph in which only a portion of the data obtained in Experiment 1 of the Example was selected to create an approximate straight line. [Figure 2] FIG. 2 shows a graph in which only a portion of the data obtained in Experiment 2 of the example was selected to create an approximate straight line. DETAILED DESCRIPTION OF THE INVENTION

[0011] The method for evaluating the persistence of fragrance compounds of the present invention includes the following steps: a step of contacting a liquid containing a first fragrance compound with the electrode surface of a QCM device, the QCM device having components of the object to be evaluated on the electrode surface, and a step of measuring the frequency change using the electrode surface of the QCM device to which the first fragrance compound is attached.

[0012] A QCM device has electrodes with a thin metal film on the front and back of a thin plate of a quartz crystal oscillator, and when an AC electric field is applied to the metal film, it can be made to vibrate at a certain frequency (resonant frequency).When just nanograms of a substance are adsorbed onto the metal film, the resonant frequency decreases according to the mass, so the amount of adsorbed substance can be quantified using a QCM device.

[0013] The inventors discovered that by immobilizing the components of an object to be evaluated on the electrodes of a commercially available QCM device, it is possible to estimate the strength of the interactions (e.g., intermolecular forces such as electrostatic attraction and van der Waals forces) between the components of the object to be evaluated and fragrance compounds. It was unexpected that the amount of fragrance compound adsorbed (attached) to the electrode on which the components were immobilized varies substantially depending on the type of fragrance compound, and that this difference strongly correlates with the difference in the strength of the fragrance compound's persistence measured by conventional measurement methods. Furthermore, it was found that measurement results using the QCM method are more reliable. While conventional measurement methods can sometimes result in variability in the assessment of persistence for some fragrance compounds with low volatility or, conversely, some extremely volatile fragrance compounds, the QCM method reduces this variability.

[0014] Here, in this specification, the term "fragrance compound" refers to, but is not limited to, the fragrance compounds described in "Japan Patent Office Gazette, Collection of Well-Known and Commonly Used Techniques (Fragrances), Part II, Food Flavors, published January 14, 2000," "Survey on the Actual Use of Food Flavoring Compounds in Japan" (2000 Ministry of Health, Labour and Welfare Science Research Report, Japan Flavor and Flavor Manufacturers Association, published March 2001), and "Synthetic Fragrances: Chemistry and Product Knowledge" (revised and expanded edition published December 20, 2016, edited by the Synthetic Fragrances Editorial Committee, Chemical Daily Co., Ltd.).

[0015] More specific examples of fragrance compounds include hydrocarbon compounds such as monoterpenes such as α-pinene, β-pinene, myrcene, camphene, and limonene, sesquiterpenes such as valencene, cedrene, caryophyllene, and longifolene, and 1,3,5-undecatriene.

[0016] Examples of alcohol compounds include saturated or unsaturated alcohols such as butanol, pentanol, 3-octanol, hexanol, (Z)-3-hexen-1-ol, prenol, and 2,6-nonadienol; terpene alcohols such as linalool, geraniol, citronellol, tetrahydromyrcenol, farnesol, nerolidol, cedrol, and terpineol; and aromatic alcohols such as benzyl alcohol, phenylethyl alcohol, and cinnamyl alcohol.

[0017] Examples of aldehyde compounds include saturated or unsaturated aldehydes such as acetaldehyde, hexanal, octanal, decanal, (E)-2-hexenal, and 2,4-octadienal; terpene aldehydes such as citronellal, hydroxycitronellal, citral, myrtenal, and perillaldehyde; and aromatic aldehydes such as benzaldehyde, cinnamaldehyde, amylcinnamaldehyde, vanillin, ethyl vanillin, heliotropin, and p-tolylaldehyde.

[0018] Ketone compounds include saturated or unsaturated ketones such as 2-heptanone, 2-undecanone, 1-octen-3-one, acetoin, methyl dihydrojasmonate, and Iso E Super, as well as diacetyl, 2,3-pentanedione, maltol, ethyl maltol, cyclotene, and 2,5-dimethyl-4-hydroxy-3(2H)-furafine. Examples of ketones include diketones and hydroxyketones such as ketone-1, ketone-2, ketone-3, ketone-4, ketone-5, ketone-6, ketone-7, ketone-8, ketone-9, ketone-10, ketone-11, ketone-12, ketone-13, ketone-14, ketone-15, ketone-16, ketone-17, ketone-18, ketone-19, ketone-20, ketone-21, ketone-22, ketone-23, ketone-24, ketone-25, ketone-26, ketone-27, ketone-28, ketone-29, ketone-30, ketone-31, ketone-32, ketone-33, ketone-34, ketone-35,

[0019] Examples of furan or ether compounds include furfuryl alcohol, furfural, rose oxide, linalool oxide, menthofuran, theaspirane, estragole, eugenol, and 1,8-cineole.

[0020] Examples of the ester compound include aliphatic esters such as ethyl acetate, isoamyl acetate, ethyl butyrate, ethyl isobutyrate, isoamyl butyrate, ethyl 2-methylbutyrate, ethyl 3-methylbutyrate, 2-methylbutyl isobutyrate, ethyl hexanoate, allyl hexanoate, ethyl heptanoate, ethyl caproate, isoamyl isovalerate, and ethyl nonanoate; terpene alcohol esters such as linalyl acetate, geranyl acetate, lavandulyl acetate, and terpenyl acetate; and aromatic esters such as benzyl acetate, benzyl butyrate, methyl salicylate, benzyl salicylate, methyl cinnamate, cinnamyl propionate, ethyl benzoate, cinnamyl isovalerate, and ethyl 3-methyl-2-phenylglycidate.

[0021] Examples of the lactone compound include saturated or unsaturated lactones such as γ-decalactone, γ-dodecalactone, δ-decalactone, δ-dodecalactone, 7-decen-4-olide, and 2-decen-5-olide.

[0022] Examples of the acid compound include saturated or unsaturated fatty acids such as acetic acid, butyric acid, octanoic acid, isovaleric acid, caproic acid, stearic acid, oleic acid, linoleic acid, and linolenic acid.

[0023] Examples of the nitrogen-containing compound include pyridine, alkyl-substituted pyrazine, methyl anthranilate, and trimethylpyrazine.

[0024] Examples of sulfur-containing compounds include methanethiol, dimethyl sulfide, dimethyl disulfide, allyl isothiocyanate, 3-methyl-2-butene-1-thiol, 3-methyl-2-butanethiol, 3-methyl-1-butanethiol, 2-methyl-1-butanethiol, and furfuryl mercaptan.

[0025] In general, fragrance compounds are used as fragrance compositions containing one or more fragrance compounds, or as consumer goods containing one or more fragrance compounds. Therefore, in this specification, the term "fragrance compound" includes not only the fragrance compound itself, but also a fragrance composition containing the fragrance compound or a consumer good containing the fragrance compound. In this specification, a fragrance composition may contain, in addition to one or more fragrance compounds, any other components (specific examples of which are described below), such as a solvent, a dispersion medium, a fragrance-imparting component, an auxiliary component such as an antioxidant, or the like, but may also consist only of a fragrance compound and a solvent. When a fragrance composition also contains components other than fragrance compounds, the concentration of the fragrance compound in the fragrance composition can be determined as desired depending on the degree of the fragrance-improving effect of the fragrance compound. When a fragrance composition consists only of fragrance compounds, it is sufficient that the composition essentially consists only of fragrance compounds based on the common knowledge of a person skilled in the art. For example, the presence of impurities remaining when a fragrance compound is purchased as a reagent is not a problem as long as they do not affect the fragrance-improving effect.

[0026] When the fragrance composition substantially contains only one or more fragrance compounds, or only one or more fragrance compounds and their solvents or dispersants (specific examples of which will be described later), the concentration of the fragrance compounds in the fragrance composition can be, for example, in the range of 1 ppt to 100%, and preferably in the range of 1 ppb to 99%.

[0027] The flavor composition can be added to consumer goods as one of the raw materials for manufacturing the consumer goods. Specific examples of the flavor composition include a flavor composition to be added to food and beverages, which are one type of consumer goods, called a flavor composition, and a flavor composition to be added to consumer goods other than food and beverages, called a fragrance composition.

[0028] The concentration of the fragrance compound in the fragrance composition can be determined arbitrarily depending on the target of the fragrance composition. As with the aforementioned composition, the amount added can be adjusted based on the concentration of the active ingredient. Examples of the concentration of the active ingredient include a range of 1 ppb to 20% based on the total mass of the fragrance composition. More specifically, the concentration can be within the range of 10 ppb to 10%, 100 ppb to 1%, or 10 ppb to 100 ppm, but is not limited to these.

[0029] In addition to the perfume compounds, the perfume composition may also contain other optional compounds or ingredients.

[0030] Specific examples of optional other ingredients that may be contained in the fragrance composition in addition to the active ingredient include various types of fragrance compounds, fragrance compositions, colorants, vitamins, functional substances, fish meat extracts, livestock meat extracts, animal and plant extracts, animal and plant oils and fats, yeast extracts, animal and plant proteins, animal and plant protein hydrolysates, starch, dextrin, sugars, amino acids, nucleic acids, organic acids, solvents, emulsifiers, specific gravity adjusters, antioxidants, etc.

[0031] The form of the fragrance composition containing the fragrance compound is preferably a solution in which the fragrance compound and other components that may be included as needed are dissolved in a water-soluble or oil-soluble solvent, an emulsion preparation, a powder preparation, or other solid preparations (such as solid fat).

[0032] Examples of water-soluble solvents include ethanol, methanol, acetone, tetrahydrofuran, acetonitrile, 2-propanol, methyl ethyl ketone, glycerin, propylene glycol, dipropylene glycol, etc. Examples of oil-soluble solvents include vegetable oils and fats, animal oils and fats, refined oils and fats (for example, processed oils and fats such as medium-chain fatty acid triglycerides, and short-chain fatty acid triglycerides such as triacetin and tripropionin), various essential oils, triethyl citrate, etc.

[0033] Furthermore, to prepare an emulsion preparation, the present composition and / or the present composition containing the present composition can be emulsified with a water-soluble solvent and an emulsifier. The emulsification method is not particularly limited, and a highly stable emulsion can be obtained by emulsifying using various types of emulsifiers that have been conventionally used, such as fatty acid monoglycerides, fatty acid diglycerides, fatty acid triglycerides, propylene glycol fatty acid esters, sucrose fatty acid esters, polyglycerol fatty acid esters, lecithin, modified starch, sorbitan fatty acid esters, Quillaja extract, gum arabic, tragacanth gum, guar gum, karaya gum, xanthan gum, pectin, alginic acid and its salts, carrageenan, gelatin, casein Quillaja saponin, or sodium caseinate, using a homomixer, colloid mill, rotating disk homogenizer, high-pressure homogenizer, or the like. The amount of these emulsifiers used is not strictly limited and can vary over a wide range depending on the type of emulsifier used, but is usually within the range of about 0.01 to about 100 parts by mass, preferably about 0.1 to about 50 parts by mass, per part by mass of the flavor composition containing the flavor compound. Furthermore, in order to stabilize the emulsified state, in addition to water, one or a mixture of two or more polyhydric alcohols such as glycerin, propylene glycol, sorbitol, maltitol, sucrose, glucose, trehalose, sugar solution, and reduced starch syrup may be added to the emulsion.

[0034] The emulsion thus obtained can be dried, if desired, to form a powder formulation. During powdering, sugars such as gum arabic, trehalose, dextrin, sugar, lactose, glucose, starch syrup, and reduced starch syrup can be added as needed. The amounts of these can be selected appropriately depending on the desired properties of the powder formulation.

[0035] In this specification, typical examples of consumer goods containing fragrance compounds (or fragrance compositions containing fragrance compounds) include cosmetics, daily necessities, health and hygiene products, and additives for the production of these products (typically fragrance compositions). More specifically, perfumes (eau de cologne, eau de toilette, eau de parfum, parfum, etc.); hair care products (shampoo, conditioner, hair styling products (hair cream, hair wax, hair balm, pomade, etc.)); cosmetics (mascara, eyebrow makeup, foundation, lipstick, lip balm, lip gloss, blush, manicure, pedicure, other nail products, etc.); skin care products (lotion, cosmetic emulsion, cosmetic cream, cosmetic gel, serum, pack, etc.); deodorant products (antiperspirant spray, deodorant sheet, deodorant cream, deodorant stick, etc.); bath additives (various types of bath additives based on inorganic salts, cooling, carbon dioxide, skin care, enzymes, and herbal medicines, etc.); suntan products (tan products, sunscreen products, etc.); body cleansers (facial cleansers (face soap, facial cleansing cream, etc.), body soap, body wash, etc.); laundry agents (laundry soap, laundry detergent, disinfectant detergent, deodorizing detergent, laundry fabric softener, etc.); kitchen supplies (kitchen detergent, kitchen bleach, kitchen deodorizer, kitchen dishcloths, gloves, kitchen disinfectant, etc.); cleaning agents (cleaning detergent, cleaning bleach, cleaning agent, cleaning dishcloths, cleaning gloves, cleaning disinfectant, etc.); health and hygiene materials (tissue paper, toilet paper, disinfectant, bandages, etc.); air fresheners (air fresheners for spaces such as indoors and cars, air fresheners for various items such as daily necessities and furniture, room fragrances, etc.); animal repellents and insecticides (insect repellents, insect repellents, insecticides, pest repellents, etc.); interior materials (wallpaper, curtains, carpets, thermal insulation sheets, etc.); various materials for manufacturing consumer goods (typically fragrance compositions (details will be described later)); etc., but are not limited to these.

[0036] In this specification, the term "evaluation subject" refers to an object that is to be evaluated for the persistence of a fragrance compound after contact with the fragrance compound (more specifically, a fragrance composition, consumer goods, etc. containing the fragrance compound), and examples thereof include fiber-based materials such as towels, cloth, and hair, and resin-based materials such as plastics and silicone.

[0037] As used herein, the term "constituent of the object to be evaluated" refers to a component that has substantially the same or similar chemical properties as the surface of the object to be evaluated, preferably a component that can be easily immobilized on the electrode surface of a QCM device. For example, if hair or wool is selected as the object to be evaluated, keratin can be selected as the component. If a cotton product is selected as the object to be evaluated, a cellulosic material, such as cellulose nanofiber, can be selected as the component. If a synthetic fiber product (e.g., nylon, polyester, etc.) is selected as the object to be evaluated, the polymer that makes up the synthetic fiber or a component that has chemically similar properties to the polymer (e.g., sharing a common functional group) can be selected. Those skilled in the art can easily select components that have similar chemical properties to the object to be evaluated, thereby enabling a strong correlation between the results of measurements using the QCM method and those using conventional methods.

[0038] The QCM device used in the present invention is not particularly limited as long as it is configured to allow a liquid containing a fragrance compound to come into contact with the electrode surface. Furthermore, the electrode surface may be configured so that components of the object to be evaluated can be immobilized by coating or the like. The method for immobilizing the components of the object to be evaluated on the electrode surface is not particularly limited, and the method described in JP 2014-190744 A can be used, for example.

[0039] It is preferable that a QCM device can measure the same frequency change value when measured under the same conditions. For example, it is preferable that a QCM device can measure the same frequency change even if measurements are taken on different measurement days, as long as the liquid containing the fragrance compound contains fragrance compounds with the same molecular number and the measurements are taken at the same temperature. By using such a QCM device, even if different fragrance compounds are measured on different days, persistence can be evaluated based on the frequency change results measured for those different fragrance compounds. In other words, it is possible to evaluate the persistence of a new fragrance compound by comparing it with past measurement data.

[0040] However, the frequency change values ​​obtained by the QCM device may vary from day to day, even when the same compound is measured at the same concentration, and the frequency change values ​​can only be used for relative comparisons between different compounds measured on the same day. In this case, the persistence evaluation method of the present invention can measure the frequency change of a first fragrance compound and then measure the frequency change of a second fragrance compound on the same day, and compare their persistence. Even if daily variations occur, normalization based on a specified fragrance compound measured at the same concentration can also allow for a comparison of the persistence of frequency changes of other fragrance compounds measured on different days. By measuring the frequency changes of multiple fragrance compounds different from the first and second fragrance compounds using the QCM device, it is possible to compare the persistence evaluations of these fragrance compounds.

[0041] The frequency change values ​​obtained by this method using a QCM device are compared with the residual rates measured by conventional methods, and the residual rates of fragrance compounds whose residual rates by conventional methods are unknown can be estimated from the frequency changes obtained by the QCM device. In this case, a scatter plot is first created between the frequency changes obtained by the QCM device and the residual rates measured by conventional methods. This scatter plot can be created based on data from, for example, 3 to 20 or 5 to 15 types of fragrance compounds.

[0042] The scatter plot is then fitted with a linear regression model to create a regression line. The regression line is created from the scatter plot by the least squares method, and may be easily created using, for example, Excel (trademark, Microsoft Corporation). When creating this regression line, it is not necessary to use all of the data of the fragrance compounds used to create the scatter plot, and the coefficient of determination (R 2 The scatter plot can be selected so that the coefficient of determination (R 2 ) is preferably selected to be 0.93 or more, 0.95 or more, 0.98 or more, or 0.99 or more.

[0043] Once such a regression line is created, the frequency changes of additional fragrance compounds can be measured using a QCM device, and the residual rates can be estimated from the regression line. Note that for plots not selected in the process of creating the regression line, the residual rates measured by the conventional method for those plots can be corrected to the residual rates on the regression line.

[0044] The measurement of the residual rate by the conventional method can be carried out as described in the following examples. That is, the measurement of the residual rate by the conventional method is carried out by a method including the following steps: a step of contacting the fragrance compound to be measured with the constituent components of the object to be evaluated; a step of extracting the fragrance compound to be measured from the constituent components of the object to be evaluated with a solvent to obtain an aroma extract; a step of distilling the aroma extract to remove non-volatile components from the aroma extract to obtain an aroma concentrate; and a step of calculating the residual rate defined by the following formula: Survival rate [%]=A / B×100 (A: Amount of the fragrance compound to be measured contained in the fragrance concentrate B: initial amount of the fragrance compound to be measured).

[0045] In the step of contacting the fragrance compound to be measured with the constituents of the evaluation object, A predetermined amount of fragrance compound is brought into sufficient contact with the constituents of the object to be evaluated, thereby adhering the fragrance compound to the constituents of the object to be evaluated. The fragrance compound to be measured can be brought into contact with the constituents of the object to be evaluated in the form of an aqueous solution, as described in the Examples. Next, in the step of extracting the fragrance compound to be measured from the constituents of the object to be evaluated with a solvent to obtain an aroma extract, an appropriate solvent is used to extract the fragrance compound adhering to the constituents of the object to be evaluated together with the solvent, thereby obtaining an aroma extract. The aroma extract is then distilled to remove non-volatile components from the aroma extract, thereby obtaining an aroma concentrate, from which the above-mentioned residual rate can be calculated. These operations can be performed by those skilled in the art by selecting an appropriate method with reference to the following Examples so as to obtain appropriate results for measuring the residual rate.

[0046] This method can include contacting a liquid containing no fragrance compounds with the electrode surface of the QCM device before contacting a liquid containing fragrance compounds with the electrode surface of the QCM device. The liquid containing no fragrance compounds can have the same composition as the liquid containing fragrance compounds, except for the fragrance compounds. This process is continued until the electrode surface is equilibrated, and then a certain amount of a sample of the liquid containing fragrance compounds can be injected into the QCM device and contacted with the electrode surface of the QCM device.

[0047] This method can also include a step of contacting a liquid containing a fragrance compound with the electrode surface of the QCM device, and then contacting a liquid not containing the fragrance compound with the electrode surface of the QCM device to which the fragrance compound is attached, before measuring the frequency change using the electrode surface of the QCM device to which the fragrance compound is attached. By continuing to contact the electrode surface with a liquid not containing the fragrance compound for a certain period of time after contacting the liquid containing the fragrance compound with the electrode surface of the QCM device, some of the fragrance compounds that have weak adhesion to the electrode surface can be washed away from the electrode surface. This allows for a clearer understanding of the differences in the strength of interaction between each fragrance compound and the components of the object to be evaluated immobilized on the electrode surface.

[0048] The fragrance compound used in the present invention is not particularly limited as long as it is a compound that can be used as a fragrance. According to the present invention, as long as it is a fragrance compound that dissolves in a solvent to form a solution, it is possible to measure fragrance compounds with low volatility and fragrance compounds with extremely high volatility.

[0049] The liquid containing the fragrance compounds used for measurement is preferably measured in a specific volume and with a specific molar concentration of the fragrance compounds. That is, it is preferable to measure the same number of fragrance compound molecules provided to the electrodes of the QCM device each time. In particular, the frequency change values ​​obtained by the QCM device may vary from day to day, even when measuring the same compound, and may only be used for relative comparisons between different compounds. In this case, multiple measurements of fragrance compounds are performed on the same day to compare their persistence. In this case, all liquids containing the fragrance compounds used for measurement must be prepared with the same molar concentration and the same volume. For example, the liquid containing the fragrance compounds used for measurement can be used in a volume of, for example, 1 μL to 1 mL, with a fragrance compound concentration of approximately 1 to 20 mmol / L, depending on the QCM device used.

[0050] The liquid containing the fragrance compound used for measurement can be a solution of the fragrance compound. The solvent for the liquid containing the fragrance compound is not particularly limited as long as it can substantially change the amount of fragrance compound attached to the coated electrode of the QCM device depending on the type of fragrance compound. Such a solvent may be an aqueous solvent. Here, the aqueous solvent may be water alone or a mixed solvent of water and other water-soluble solvents. Examples of other water-soluble solvents include various solvents such as alcohol, ether, and ketone, and particularly an aqueous alcohol solution. The aqueous alcohol solution may be an aqueous methanol solution, an aqueous ethanol solution, an aqueous 2-propanol solution, or the like, and may be an aqueous alcohol solution containing, for example, 10% to 90% by mass, preferably 20% to 70% by mass, of alcohol.

[0051] A solubilizer can be added to a liquid containing a fragrance compound depending on the solvent and fragrance compound used. For example, when a highly hydrophilic aqueous methanol solution is used as a solvent, some fragrance compounds may be difficult to dissolve, so a solubilizer can be used as appropriate. Examples of solubilizers that can be used include surfactants and polyhydric alcohols. Those skilled in the art can select anionic surfactants, cationic surfactants, nonionic surfactants, zwitterionic surfactants, polyhydric alcohols, etc., depending on the fragrance compound and solvent used.

[0052] Specifically, examples of anionic surfactants include sodium laureth sulfate, ammonium laureth sulfate, sodium lauryl sulfate, sodium cocoyl methyl taurine, sodium lauroyl methyl alanine, TEA lauroyl sarcosine, sodium cocoyl glutamate, sodium cocoyl isethionate, sodium olefin (C14-16) sulfonate, and sodium dilauroyl glutamate lysine; examples of cationic surfactants include alkyltrimethylammonium chloride, dialkyldimethylammonium chloride, behentrimonium chloride, and distearyldimonium chloride N. Examples of nonionic surfactants include polyoxyethylene tridecyl ether, sorbitan stearate, POE alkyl ether, polyoxyethylene hydrogenated castor oil, cocamide MEA, cocamide methyl MEA, cocamide DEA, polysorbate-20, glyceryl caprate, and decyl glucoside; examples of amphoteric surfactants include cocamidopropyl betaine, lauramidopropyl betaine, sodium cocoamphoacetate, palm kernel fatty acid amidopropyl betaine, and lauryl hydroxysultaine.

[0053] The solubilizer may be used at 3% by weight or less, 2% by weight or less, or 1% by weight or less of the liquid containing the fragrance compound, and may be used at 0.1% by weight or more, 0.3% by weight or more, or 0.5% by weight or more.

[0054] The present invention will be explained in more detail in the following examples, but the present invention is not limited thereto. [Example]

[0055] Experiment 1: Experiment using keratin (artificial hair) <Measurement by QCM> The electrode part of the quartz crystal oscillator of a commercially available QCM device (NAPiCOS Auto, Nihon Dempa Kogyo Co., Ltd.) was coated with keratin. Specifically, 20 μL of keratin was dropped onto the QCM sensor, which was then dried in a thermostatic chamber at 50°C and washed with pure water to remove excess keratin.

[0056] Samples were prepared by adding an appropriate solubilizer to 25 mL of an ethanol aqueous solution diluted appropriately with water, and then dissolving the fragrance compounds shown in Table 1 in a range of approximately 0.01% by mass to 0.10% by mass so as to have the same molar concentration.

[0057] At room temperature (20°C), the above ethanol aqueous solution was injected into the QCM device, and after a certain period of time, 100 μL of the above sample was injected. The above ethanol aqueous solution was then further injected and allowed to flow for a certain period of time. The maximum change in the frequency of the measured quartz crystal oscillator over time was recorded for each fragrance compound. The results are shown in Table 1.

[0058] <Measurement by conventional method> 1.0 g of shampoo (one example of consumer goods) containing 1% by mass of a fragrance composition (equimolar mixture of fragrance compounds) containing the same amount of fragrance compounds to be examined for residual rate was dissolved in water. The artificial hair was immersed in the solution for 10 minutes, and then dried with cold air for 10 minutes, followed by extraction with diethyl ether (solvent) to obtain an extract.

[0059] The resulting extract was distilled to remove non-volatile components, and the volatile components including the fragrance compounds were cooled to obtain a distillate (hereinafter referred to as "fragrance concentrate"), which was analyzed by gas chromatography to quantify the fragrance compounds.

[0060] From the obtained results, the survival rate was calculated as follows.

[0061]

number

[0062] <result> The results obtained for each fragrance compound by conventional and QCM measurements are shown in the table below:

[0063] [Table 1]

[0064] Figure 1A shows a scatter plot of these results, with the vertical axis representing the residual rate measured by the conventional method and the horizontal axis representing the frequency change measured by QCM. Figure 1A also shows an approximate line based on a linear regression model created based on all the data for the fragrance compounds measured in this study. The coefficient of determination (R 2 ) was 0.6401.

[0065] Figure 1B shows the fitted line of the linear regression model created after excluding the data of lilial and isoambrettolide from the fragrance compounds measured in this study. The coefficient of determination (R 2 ) was an extremely high value of 0.9889. The survival rate calculated from the obtained approximation line is also shown in Table 1.

[0066] Thus, the coefficient of determination (R 2 ) so that the coefficient of determination (R 2 By selecting data such that the value of (R) is 0.90 or higher, preferably 0.95 or higher, it is possible to link the measurement results obtained by the conventional method with the measurement results obtained by QCM. Furthermore, the data selected here can be considered to be data on fragrance compounds for which the measurement results obtained by the conventional method and the measurement results obtained by QCM match.

[0067] On the other hand, the data not selected here can be considered to be data on fragrance compounds for which the conventional method would not yield accurate results. For such fragrance compounds, if a linear fit with a very high coefficient of determination is obtained as described above, the (incorrect) residual percentage actually measured by the conventional method can be corrected to the true residual percentage that should have been measured by the conventional method based on the QCM measurement results. Specifically, as shown in Table 1, the residual percentage of lilial measured by the conventional method as 0.76% can be corrected to 2.54% using the linear fit shown in Figure 1B. Similarly, the residual percentage of isoambrettolide measured as 3.15% using the conventional method can be corrected to 5.80% using the same linear fit.

[0068] Furthermore, as mentioned above, if an approximation line with a very high coefficient of determination is obtained, it is possible to estimate (predict) the residual rate of fragrance compounds that have not actually been measured by conventional methods, simply by measuring them with QCM. As mentioned above, conventional measurement methods for evaluating the residual rate of fragrance compounds are very time-consuming, so it is possible to select a group of fragrance compounds for which an approximation line with a high coefficient of determination can be obtained with a small number of samples, measure them using both the conventional method and QCM, and then estimate (predict) the residual rate of other fragrance compounds from the approximation line using only QCM measurements.

[0069] Experiment 2: Experiment using cellulose nanofiber (pseudo towel) <Measurement by QCM> The frequency change was measured using the QCM method in the same manner as in Experiment 1, except that the electrode part of the quartz crystal oscillator was coated with cellulose nanofiber instead of keratin.

[0070] <Measurement by conventional method> The remaining rate was measured by the conventional method in the same manner as in Experiment 1, except that a cotton towel was used instead of the artificial hair and a commercially available fabric softener was used instead of the shampoo.

[0071] <result> The QCM and conventional measurement results for each fragrance compound are shown in Table 2 below:

[0072] [Table 2]

[0073] These results are shown in Figure 2, which is a scatter plot of the residual rate measured by the conventional method on the vertical axis and the frequency change measured by QCM on the horizontal axis. The figure shows the approximate line of a linear regression model created after excluding data for three compounds: methyl cedryl ether, cis-3-hexenyl acetate, and ethyl maltol. The coefficient of determination (R 2 ) was an extremely high value of 0.9901. The survival rate calculated from the obtained approximation line is also shown in Table 2.

[0074] Even if the approximate line is created without excluding these three data points, the coefficient of determination (R 2 ) is a relatively high value of 0.9395. In this case, although it is possible to create an approximate line without excluding all or part of the three data points, a more useful approximate line can be obtained by selecting data points that result in an extremely high coefficient of determination.

[0075] Once an approximate line with such a high coefficient of determination is obtained, the residual rates of additional fragrance compounds can be estimated (predicted) solely by QCM measurements, as described in Experiment 1.

[0076] Experiment 3: Conventional method Measurements of methyl cedryl ether and lilial were carried out three times using the conventional method using the cotton towels in Experiment 2. As a result, it was found that there was variability in the measurement results as shown below. These are fragrance compounds with low volatility, and for such fragrance compounds, it is useful to correct the residual rates obtained by the conventional method based on measurements using QCM, as in Experiments 1 and 2, or to estimate (predict) the residual rates obtained by the conventional method from measurements using QCM.

[0077] [Table 3]

[0078] Furthermore, although not shown in Table 3, for extremely volatile fragrance compounds, losses due to distillation are likely, and therefore, it is thought that the variability will be large for such fragrance compounds as well. For such fragrance compounds, it is useful to correct the residual rate obtained by the conventional method based on QCM measurements, as in Experiments 1 and 2, or to estimate (predict) the residual rate obtained by the conventional method from QCM measurements. On the other hand, although not shown in Table 3, for fragrance compounds with moderate volatility, the variability was around 10%, and the variability shown in Table 3 did not occur. As mentioned above, such fragrance compounds can be useful for creating an approximation line with a high coefficient of determination.

Claims

1. A method for evaluating the persistence of a fragrance compound, comprising the steps of: (a) contacting a liquid containing a first flavor compound with an electrode surface of a QCM device; and (b) measuring a change in the frequency of a quartz crystal oscillator caused by the first flavor compound being adsorbed onto the electrode surface; In the step (a), the electrode surface of the QCM device contains a constituent component of the object to be evaluated.

2. 10. The method of claim 1 further comprising the steps of: (c) contacting a liquid containing a second flavor compound with the electrode surface of the QCM device; (d) measuring a change in the frequency of the quartz crystal oscillator due to the attachment of the second fragrance compound; (e) comparing the frequency change caused by the second fragrance compound with the frequency change caused by the first fragrance compound.

3. 3. The method according to claim 2, comprising carrying out the following steps for each of a plurality of fragrance compounds different from the first fragrance compound and the second fragrance compound: (f) contacting the liquid containing the flavor compound with the electrode surface of the QCM device; (g) measuring a change in the frequency of the quartz crystal oscillator due to the attachment of the fragrance compound; (h) comparing the frequency change caused by the fragrance compound with the frequency changes caused by the first fragrance compound and the second fragrance compound;

4. measuring the residual ratio of the first, second and / or multiple fragrance compounds to the evaluation object; creating a scatter diagram in which the frequency change obtained by the method according to claim 3 and the survival rate are plotted; When the scatter plot was fitted with a linear regression model, the coefficient of determination (R ２ ) is 0.90 or more, and creating a regression line by selecting the plots; measuring said frequency shift for additional fragrance compounds and estimating said survival rate from said regression line; Here, the residual rate is measured by a method including the following steps: a step of contacting a fragrance compound to be measured with a component of the object to be evaluated; a step of extracting the aroma compound to be measured from the constituent components of the evaluation object with a solvent to obtain an aroma extract; a step of distilling the aroma extract to remove non-volatile components from the aroma extract, thereby obtaining an aroma concentrate; Calculating the survival rate defined by the following formula: Survival rate [%] = A / B x 100 (A: Amount of the fragrance compound to be measured contained in the fragrance concentrate B: initial amount of the fragrance compound to be measured).

5. The method according to claim 4, further comprising the step of correcting the survival rate to a survival rate on the regression line for plots not selected in the step of creating the regression line.

6. The method of claim 1 , wherein the liquid containing the fragrance compound is a water-based solution.

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