JP2016163880A - Method for removing sulphur-containing compound in liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide new means for specifically removing a sulphur-containing compound including polysulfide such as DMTS without spoiling umami components, flavor components and the other components, from various kinds of liquids containing beverage.SOLUTION: Inventors have found as a result that: it is possible to absorb and remove DMTS without spoiling flavor components such as isoamyl acetate and ethyl caproate by using as an absorbent, fine particles of late-periodic transition metal, carried on a carrier and having a nano size or less; it is possible to absorb and remove by the absorber, various sulphur-containing compounds to be a factor of sulfide-like off-flavor without spoiling umami/flavor components of various kinds of beverages; and it is possible to absorb and remove DMTS from not only an aqueous liquid but also a liquid of a lipophilic organic compound.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a method for removing sulfur-containing compounds in a liquid, and a method for reducing sulfide-like off-flavours in beverages such as scent of sake.

  Dimethyl trisulfide (DMTS) is a substance produced by the storage of sake and has a sulfur-like and onion-like odor. It is a main component of scent, which is a deteriorated odor of sake (Non-Patent Document 1). Sulfur-containing compounds such as DMTS can cause sulfide-like off-flavors in various beverages other than sake (Non-Patent Documents 2 and 3). In recent years, the popularity of refined sake has been increasing in other countries, and exports to foreign countries have a longer transportation and storage period, so it is increasingly important to control the occurrence of DMTS in sake during storage. It has become.

  For example, low temperature storage and control of dissolved oxygen concentration (Non-Patent Document 4) are known as methods for controlling old perfume. However, these methods require facilities such as a cooling system and a nitrogen replacement device, and it is costly to perform such aroma control uniformly for all the sake produced.

  Other known methods for controlling scent by treating with adsorbent include a method using silica gel as an adsorbent (Patent Document 1), a method using dealuminated Y-type zeolite as an adsorbent (Patent Document 2), and the like. . However, these adsorbents are not necessarily specialized for the main constituents of Senka.

  On the other hand, a gold nanoparticle catalyst in which gold nanoparticles are supported on a metal oxide support can be used as an adsorptive desulfurization agent for adsorbing and removing sulfur-containing organic compounds in liquid fuel, specifically, organic compounds having a thiophene ring. Is known (Patent Document 3). However, there is no disclosure of removal of sulfur-containing compounds such as polysulfide in beverages. There is no specific disclosure about adsorption removal of sulfur-containing organic compounds other than thiophene rings, and utilization of metal nanoparticles other than gold.

Japanese Patent No. 4908296 Japanese Patent Publication No. 3-29385 Japanese Patent No. 5170591

Journal of Japan Brewing Association, 101, 125-131, 2006 J. Agric. Food Chem. 48, 6196-6199, 2000 J. Am. Soc. Brew. Chem. 56, 99-103, 1998 Journal of Japan Brewing Association, 94, 827-832, 1999

  The present invention can specifically remove sulfur-containing compounds including polysulfides such as DMTS from various liquids including beverages without damaging other components such as umami components and aroma components. It aims at providing the novel means which can reduce the old perfume of refined sake simply at low cost.

  As a result of earnest research, the inventors of the present application can adsorb and remove DMTS without impairing aromatic components such as isoamyl acetate and ethyl caproate, by using fine particles of late transition metal of nano size or less as an adsorbent, Adsorbents can adsorb and remove various sulfur-containing compounds that cause sulfide-like off-flavors without compromising the umami and aroma components of various beverages, and can be used not only from aqueous liquids but also from lipophilic organic compound liquids. The present invention was completed by finding that adsorption removal of DMTS is possible.

  That is, this invention provides the removal method of the sulfur-containing compound in a liquid including making the fine particle of late period transition metal contact with a liquid. Moreover, this invention provides the method of reducing the sulfide-like off-flavor of a drink including removing the sulfur-containing compound in a drink by the sulfur-containing compound removal method of the said invention. Furthermore, the present invention provides a method for reducing the scent of sake, including removing polysulfides in the sake by the method for removing sulfur-containing compounds of the present invention. Furthermore, the present invention provides a beverage with reduced sulfide-like off-flavor by the above-described method of the present invention, and sake with reduced aroma. Furthermore, this invention provides the adsorption agent of the sulfur-containing compound in the liquid containing the fine particle of late period transition metal. Furthermore, the present invention provides a liquid container such as a beverage container in which the adsorbent of the present invention is immobilized.

  The present invention provides means capable of specifically removing sulfur-containing compounds such as polysulfides such as DMTS without impairing the umami and aroma components of beverages. The fine particles of late transition metals such as gold and platinum can adsorb and remove DMTS, which is a major component of scent, without impairing the flavor components of sake such as isoamyl acetate and ethyl caproate. Therefore, according to the present invention, it is possible to provide a beverage such as sake with reduced sulfide-like off-flavour such as scent while maintaining the umami component and the aroma component. Further, according to the present invention, DMTS can be adsorbed and removed from a liquid of an oleophilic organic compound, so that the sulfur concentration in an organic solvent or liquid fuel can be more strictly reduced than in the prior art.

Gold / glycine complex impregnation method using (standard condition) Au supported silica prepared by _{(1 wt% Au / SiO 2} - (G-3)) is a result of DMTS examining the adsorption capacity. Gold / glycine complex impregnation method using (baking time 30 changes in minutes) Au supported silica prepared by _{(1 wt% Au / SiO 2} - (G-7)) is the result of DMTS examining the adsorption capacity. Gold / glycine complex impregnation method using Au supported silica prepared by (change the firing temperature to 200 ℃) (1 wt% Au / SiO 2 - (G-8)) is a result of DMTS examining the adsorption capacity. It is the result of investigating the DMTS adsorption capacity of a commercially available Au-supported silica catalyst (1 wt% Au / SiO _2- (H)). DMTS adsorption ability of Au-supported silica (1 wt% Au / SiO _2- (G-1)) prepared by impregnation method using gold / glycine complex (using 10 mL of water for dissolution and evaporation drying) was investigated. It is a result. It is the result of investigating DMTS adsorption ability of Au-supported silica (1 wt% Au / SiO _2- (G-9)) prepared by impregnation method using gold / glycine complex (silica support changed to Q-3) . Au supported silica prepared by DR method _{(0.5 wt% Au / SiO 2} - (DR)) is the result of DMTS examining the adsorption capacity. Gold / beta-alanine complex Au supported silica was prepared by impregnation method using _{(1 wt% Au / SiO 2} - (A)) is the result of DMTS examining the adsorption capacity. Gold / 4-aminobutyric acid complex Au supported silica was prepared by impregnation method using _{(1 wt% Au / SiO 2} - (GABA)) is the result of DMTS examining the adsorption capacity. It is the result of investigating the DMTS adsorption ability of Ag supported silica Ag supported silica (1 wt% Ag / SiO ₂ ) prepared by the impregnation method using silver nitrate. It is the result of investigating the DMTS adsorption ability of Pt carrying silica (1 wt% Pt / SiO ₂ ) prepared by the impregnation method using chloroplatinic acid. It is the result of investigating the DMTS adsorption ability of Pd carrying silica (1 wt% Pd / SiO ₂ ) prepared by the impregnation method using palladium nitrate. Au-supported aluminum-containing mesoporous silica (1 wt% Au / Al-MCM-41- (A)) in which gold particles are impregnated and supported on an aluminum-containing mesoporous silica (Al-MCM41) support using a gold / β-alanine complex It is the result of investigating the DMTS adsorption ability. It is the result of having investigated DMTS adsorption ability of Au carrying | support montmorillonite (1 wt% Au / Mont) which impregnated and carry | supported the gold particle on the montmorillonite support | carrier using the gold / (beta) -alanine complex. It is the result of the sensory evaluation of the sake processed with various adsorbents. It is the result of investigating DMTS adsorption ability in hexane of Au carrying silica (the first experiment). It is the result of investigating DMTS adsorption ability in hexane of Au carrying silica (the second experiment).

  In the present invention, fine particles of late transition metal are used as an adsorbent for adsorbing and removing sulfur-containing compounds in a liquid.

  A sulfur-containing compound is a compound containing a sulfur atom in its chemical structure. The sulfur-containing compounds that are the subject of the present invention include various sulfur-containing compounds that occur or exist in liquids such as beverages, organic solvents, and liquid fuels, and that can cause sulfide-like off-flavours in beverages. Is included. Specific examples include polysulfides such as dimethyl trisulfide (DMTS) and dimethyl disulfide (DMDS). These polysulfides, especially DMTS, are known to be the main constituents of scent, which is a deodorant odor of sake, and in various beverages including alcoholic beverages other than sake, they are produced during production or storage. It is known to occur and cause sulfide-like off-flavours. There is also a need for a technique for reducing the concentration of sulfur-containing compounds even in liquids of lipophilic organic compounds such as liquid fuel sulfur-free. By treating the liquid with the adsorbent, sulfur-containing compounds in the liquid can be adsorbed and removed, and sulfide-like off-flavor can be reduced in beverages. The term sulfide-like off-flavor or reduced scent includes the prevention of these occurrences.

  The target liquid in the present invention includes various inorganic and organic liquids. It may be a lipophilic liquid or a hydrophilic liquid. In one embodiment, the liquid of interest is a beverage. In another embodiment, the liquid of interest is an organic solvent. In yet another aspect, the liquid of interest is a liquid fuel.

  The beverage is not particularly limited, and may be an alcoholic beverage or a non-alcoholic beverage. Examples of the alcoholic beverage include various alcoholic beverages such as sake, wine, beer, whiskey, brandy, and mixed alcohol. Among them, particularly preferable examples include sake. Examples of non-alcoholic beverages include juices made from vegetables, fruits and the like, and various beverages such as coffee, tea, Japanese tea, barley tea, Chinese tea, and carbonated beverages.

  Specific examples of the organic solvent include benzene, toluene, xylene, naphthalene, phenol, cresol, hexane, heptane, octane, cyclohexane, cyclopentane, and substituted products of these alkyl groups, and mixtures of two or more of these. Can be mentioned.

  Liquid fuels include various organic liquid fuels. Specific examples include fossil liquid fuels such as gasoline, kerosene, light oil, and heavy oil, bioethanol, biodiesel, bioethyl tert-butyl ether (bioETBE), and biomethanol. And bioliquid fuels such as biobutanol, and mixtures of two or more thereof.

  In the present invention, the late transition metals include gold, silver, platinum, palladium, ruthenium, rhodium, osmium, iridium, iron, cobalt, nickel, copper, and zinc, and at least one of these metals Can be used. Among them, examples of metals that can be preferably used include at least one selected from the group consisting of gold, silver, platinum, and palladium, in particular, gold, but are not limited thereto.

  The particle size (particle diameter) of the late transition metal fine particles may have an average particle size of 50 nm or less, preferably 30 nm or less, such as 20 nm or less, or 10 nm or less. It has been confirmed by experiments using gold particles that the adsorption capacity of the sulfur-containing compound DMTS tends to be higher as the average particle size of the metal fine particles is smaller (see Examples below). However, since the particle size particularly suitable for adsorption of the sulfur-containing compound can vary depending on the type of metal, the size of the fine particles can be selected as appropriate. The lower limit of the fine particle size is not particularly limited, and even particles composed of about 1 to several metal atoms can be used for adsorption of sulfur-containing compounds. The atomic radius of the late transition metal is approximately 1.4 to 1.8 mm.

  The particle size described above is a crystallite diameter measured by direct observation with a transmission electron microscope (TEM) or by powder X-ray diffraction (XRD). In the present invention, the particle size measured by at least one of the methods may be in the above range.

  The fine particles of late transition metal may be in a form supported on a carrier. The type of the carrier is not particularly limited, and any carrier can be used as long as it can carry the late transition metal in the form of nano-sized particles or less on the surface thereof. Specific examples of the carrier that can be used in the present invention include silicon materials (silica, silica-alumina, aluminosilicate, etc.), carbon materials (activated carbon, various porous carbon materials, etc.), metal oxides (iron oxide). Aluminum oxide, titanium oxide, cobalt oxide, zirconium oxide, cerium oxide, manganese oxide, zinc oxide, nickel oxide, magnesium oxide, tungsten oxide, etc.), clay (bentonite, activated clay, diatomaceous earth, montmorillonite, etc.), synthetic or natural polymer (Various synthetic resins, polyvinylpyrrolidone, chitosan, microfibrous cellulose, tannin, agar, gelatin, etc.), carbonates (magnesium carbonate, calcium carbonate, barium carbonate, etc.), porous coordination polymers (PCP) Composed of metal ions and organic ligands that crosslink them A crystalline polymer structure, metal organic structures (Metal-Organic Framework; MOF) also called), there may be mentioned boron nitride, and the like.

  When used to remove sulfur-containing compounds in beverages or reduce off-flavours, use carriers that are approved for use in beverages under relevant regulatory laws and regulations, such as the Food Sanitation Act and Liquor Tax Act, as necessary. May be. Specific examples of such carriers include activated carbon, bentonite, activated clay, diatomaceous earth, silica, silica-alumina, aluminosilicate, chitosan, montmorillonite, phytic acid, agar, gelatin, sodium alginate, carrageenan, and microfibrous cellulose. , Wheat flour, gluten, egg white, straw tannin, tannin, polyvinylpyrrolidone, wood chips, collagen, papain, protease, pectinase, hemicellulase, pea protein, β-glucanase, and casein or sodium caseinate. These carriers are also examples of carriers that can be preferably used in the present invention. Among them, activated carbon (except for ketjen black for sake) is particularly preferable as a carrier that can be particularly preferably used for reducing the aroma of sake. And at least one selected from bentonite, activated clay, diatomaceous earth, silica, silica-alumina, aluminosilicate, chitosan, and montmorillonite. However, even when used for beverages such as sake, for example, in the range that is recognized as a device, it is not limited to the carrier approved as a food additive as described above, and various carriers are adopted. be able to.

  The carrier on which the late transition metal fine particles are supported may have any shape and form. For example, it may be in the form of powder, granules, pellets, or may be a form fixed to at least the inner wall surface of a liquid container such as a beverage container (such as a liquor bottle). By using such a liquid container, it becomes possible to remove sulfur-containing compounds in the distribution process. For example, it can adsorb and remove sulfur-containing compounds that are generated in the liquid before consumption or use after production, and can reduce the occurrence of sulfide-like off-flavours in beverages and the occurrence of aroma in sake. .

The specific surface area of the carrier is not particularly limited, but a porous carrier having a large specific surface area (for example, about 30 m ² / g or more, particularly about 100 m ² / g or more) is preferably used to reduce the size of the metal fine particles. Can do. The upper limit of the specific surface area is not particularly limited, but is usually about 3000 m ² / g or less.

  Late transition metal microparticles are particularly well known in the field of catalysts, in which various techniques are known for producing metal microparticle catalysts in a form supported on a support. Specific examples include a precipitation method, a coprecipitation method, a precipitation reduction method, a sol immobilization method, a solid phase mixing method, a gas phase grafting method, and an impregnation method. With respect to the support of the gold fine particles, for example, a method described in International Publication WO 2012/144532 can also be mentioned. The metal fine particles used for removing the sulfur-containing compound in the present invention may be produced by any method. A person skilled in the art can produce metal fine particles satisfying the conditions of the present invention by selecting an appropriate production method according to the type of metal used. As examples of commercially available products, there are various commercially available products in which nano-sized metal fine particles are supported on a metal oxide or the like. In the present invention, such commercially available products can also be used.

  The impregnation method is one of the preferred methods for producing a material in which fine particles of late transition metal are supported on a carrier at a low cost. The method described in the above-mentioned WO 2012/144532 is also an impregnation method in which a chloride ion-free impregnation solution is prepared using gold acetate. In addition, as described in the following Examples, using a metal / amino acid compound complex in which an amino acid or an amino acid analog (which may be collectively referred to as “amino acid compound”) is coordinated to a late transition metal It is also possible to prepare an impregnation liquid.

  The late transition metal / amino acid compound complex is a complex in which an amino acid or an amino acid analog compound is dissolved in a basic alcohol aqueous solvent, an alcohol aqueous solution of a late transition metal soluble compound is added thereto, and alcohol is further added. It can be prepared by precipitating and recovering it and washing it again after appropriate precipitation with alcohol. Examples of the late transition metal soluble compound include chloroauric acid in the case of gold, chloroplatinic acid, platinum nitrate in the case of platinum, and palladium chloride and palladium nitrate in the case of palladium. As late transition metal / amino acid complexes, complexes of gold with glycine, histidine, and tryptophan are known (Pharmaceutical Chemistry Journal, 1999, vol. 33, No. 9, p. 11-13).

  The kind of amino acid that can be used for preparing the complex is not particularly limited. Representative examples include 20 α-amino acids constituting natural proteins, but are not limited to these, and β-, γ-, and δ-amino acids are also included. The amino acid may be D-form or L-form. Specific examples include arginine, histidine, lysine, aspartic acid, glutamic acid, alanine, glycine, leucine, valine, isoleucine, serine, threonine, phenylalanine, tryptophan, tyrosine, cystine or cysteine, glutamine, asparagine, proline, methionine, β -Alanine, γ-aminobutyric acid (4-aminobutyric acid), carnitine, γ-aminolevulinic acid, γ-aminovaleric acid, δ-aminovaleric acid (5-aminovaleric acid), ε-aminocaproic acid (6-aminocaproic acid) Etc.

The amino acid analog compound that can be used for preparing the complex is not particularly limited as long as it has a structure similar to an amino acid. Examples of amino acid analogs include
A compound in which at least one (for example, all or one or two, or one) amino group of an amino acid molecule is replaced with a sulfhydryl group;
A compound in which at least one alkyl group is bonded to at least one (for example, all, one, two, or one) amino group of an amino acid molecule (the alkyl group has, for example, 1 to 5, 1 to 4, 1-3, 1, 2 or 1);
At least one (for example, 1 to 5, or 1 to 3, or 1 or 2, or 1) of carbon atoms constituting the main chain and side chain of the amino acid molecule is a nitrogen atom, an oxygen atom, and a sulfur atom. A compound substituted with at least one selected from: and at least one of carbon atoms constituting the main chain and side chain of the amino acid molecule (for example, 1-5, 1-4, 1-3, 1, or A compound in which at least one selected from the group consisting of an alkyl group, a hydroxyl group and a halogen atom is bonded to two or one (the carbon number of the alkyl group is, for example, 1 to 5, 1 to 4, 1 to 3) Piece, one piece, two pieces, or one piece)
Etc.

Specific examples of amino acid analogs include thiomalic acid (aspartic acid analog in which the —NH ₂ group of aspartic acid is replaced with —SH group), p-chlorophenylalanine (phenylalanine in which the para position of the phenyl group is substituted with a chlorine atom) Similar compounds), β-chloroalanine (Alanine analogs in which the β carbon is replaced by chlorine atoms), hydroxyproline (hydroxylated proline, collagen component), hydroxylysine (hydroxylated lysine, collagen component) Sarcosine (N-methylglycine, a glycine-like compound in which one methyl group is bonded to the amino group of glycine), and the like, but is not limited thereto.

  To impregnate the carrier of the late transition metal / amino acid compound complex on the carrier, dissolve the complex in a small amount of water, add the carrier to this, stir and mix for several minutes to several tens of minutes, and then 100 ° C to 600 ° C. What is necessary is just to carry out by baking for about several minutes to about ten and several hours. In the impregnation method using a complex, the type of carrier is not limited, and even an acidic carrier which is usually difficult to use can be used. The size of the metal fine particles on the support can be reduced by impregnating the support with the complex aqueous solution and impregnating the support with the complex and immediately subjecting the support to a baking treatment without drying.

  A plurality of types of adsorbents for late transition metal fine particles to be brought into contact with the liquid may be used in combination. For example, a material in which a plurality of metal fine particles are simultaneously supported on the same carrier may be used, or a mixture of the same type of metal fine particles supported on different types of carriers may be used. Alternatively, different metal fine particles supported on the same type or different types of carriers may be mixed and used.

  The treatment of the liquid product with the adsorbent may be performed in the manufacturing process (typically the final step) of the liquid product. In addition, after the liquid product is manufactured and before it is provided to the end consumer, the liquid product may be contacted with the adsorbent, and as a result, sulfur-containing compounds generated during transportation and storage of the liquid product. Can also be removed. Furthermore, as described above, if an adsorbent is fixed to at least the inner wall of various liquid containers such as liquor containers such as liquor bottles, it is generated after the liquid is sealed in the container, or Sulfur-containing compounds mixed at the time of encapsulation can also be removed by adsorption. For beverages, by using the adsorbent as described above, it is possible to remove not only sulfur compounds generated during the manufacturing process but also sulfur compounds generated during transportation and storage, thereby providing a sulfide-like off-flavor. Can be reduced.

  Hereinafter, the present invention will be described more specifically based on examples. However, the present invention is not limited to the following examples.

1. DMTS adsorption experiment using Au supported silica (Au / SiO ₂ ) 1
Commercially available gold nanoparticle catalyst (1 wt% Au / SiO ₂ manufactured by Halta Gold, gold particle size 7.1 nm), gold-supported silica prepared by precipitation reduction (DR) method, and impregnation method using gold / amino acid complex DMTS adsorption experiment was conducted using the prepared Au-supported silica.

<Preparation of Au-supported silica>
(1) DR method 250 mL of water, 990 mg of silica gel, and 11 mg of [Au (en) ₂ Cl ₃ ] were added to an eggplant flask. After stirring at 0 ° C. for 30 minutes, 0.01 M NaBH ₄ 3.8 mL was slowly added dropwise over 10 minutes. After stirring for 1 hour, it was collected by filtration, washed with water, and dried in vacuo. The average particle size (measured by XDR) of the obtained Au-supported silica Au / SiO _2- (DR) was 11.0 nm.

(2) Impregnation method using gold / amino acid complex
(2-1) Preparation of gold / glycine complex Sodium hydroxide 2.5 mmol and glycine 2.5 mmol were dissolved in 2 mL of water in a beaker, and 3 mL of ethanol was added. In a flask, 0.32 mmol of chloroauric acid tetrahydrate was dissolved in 1 mL of water, and 4 mL of ethanol was added. The chloroauric acid solution in the flask was added to a beaker, washed with 6 mL of ethanol, and then left overnight in a freezer. The clear supernatant was removed, the precipitate was dissolved with a small amount of water, reprecipitated with ethanol, and the supernatant was discarded with a centrifuge. Centrifugal washing was performed twice with ethanol. The gold / glycine complex Au (gly) (OH) _{2 was} collected by filtration and dried in vacuo.

(2-2) Gold impregnation support on carrier 15 mg of gold / glycine complex is placed in a mortar, 0.5 mL of water is added and dissolved, and 990 mg of SiO ₂ (Fuji Silysia Chemical, CARiACT Q-15, specific surface area) 200 m ² / g) was added and mixed with stirring for 30 minutes. Thereafter, air baking (300 ° C., 4 hours) was immediately performed without drying, and gold particles were supported on SiO ₂ .

(2-3) Examination of Impregnation Support Conditions Based on the above condition (2-2), the impregnation support conditions were examined by changing the conditions in various ways. The examined conditions and the results (average particle diameter of supported gold particles, measured by XRD) are shown together in Table 1 below.

<DMTS adsorption experiment method>
DMTS and internal standard diethylene glycol dimethyl ether were added to ethanol and mixed. 10 μL of this was diluted with 4 mL of ethanol to adjust the DMTS concentration to 1.48 × 10 ⁻⁴ mmol (4.69 pm). Au / SiO ₂ was added to this solution, and the state of adsorption was confirmed by gas chromatography (GC). The amount of Au / SiO ₂ used was adjusted so that Au / DMTS = 15-20.

<Result>
Conditions sized gold nanoparticles are small [1], [3] and Au / SiO _2, and commercially available Au / SiO ₂ of [4] (Haruta _{Gold, Au / SiO 2 - (H} )) adsorption experiment using The results of performing are shown in FIGS. 1-1 to 1-4. Also, the results of adsorption experiments using Au / SiO ₂ under slightly larger conditions [2] and [5] and Au / SiO ₂ of DR method are shown in FIGS. 1-5 to 1-7. . It was observed that the smaller the size of the gold particles supported on the carrier, the higher the adsorption capacity of DMTS. When an adsorption experiment was performed with gold foil, DMTS was not adsorbed at all.

2. DMTS adsorption experiment 2 using Au supported silica (Au / SiO ₂ ) 2
Gold / amino acid compound complexes were prepared using amino acids other than glycine and amino acid analogs, and Au-supported silica was prepared using the gold / amino acid compound complexes, and DMTS adsorption experiments were performed.

<Preparation of Au-supported silica>
Using β-alanine, 4-aminobutyric acid, lysine, asparagine, D, L-alanine, 5-aminovaleric acid, 6-aminocaproic acid, methionine, glutamic acid, histidine, tryptophan as amino acids, and thiomalic acid as an amino acid analog A gold / amino acid compound complex was prepared by the same procedure as in 1 (2-1) above. A gold / amino acid compound complex (equivalent to 10 mg of gold) was placed in a mortar, dissolved by adding 0.5 mL of water, 990 mg of SiO ₂ was added thereto, and the mixture was stirred and mixed for 30 minutes. Thereafter, air baking was performed at 300 ° C. for 4 hours without drying to obtain Au-supported silica. For some amino acids, complex preparation and Au-supported silica were prepared twice.

  When the average particle diameter of each Au-supported silica was measured by XRD, 4.5 nm or 2.6 nm using β-alanine, 4.1 nm or 7.9 nm using 4-aminobutyric acid, 12.3 nm using lysine, 7.7 nm or 6.9 using asparagine. nm, 7.3 nm using 5-aminovaleric acid, 8.5 nm using 6-amino acid caproic acid, 14.0 nm using methionine, 5.2 nm using glutamic acid, 6.5 nm using histidine, 5.0 nm using tryptophan, using thiomalic acid It was 3.5 nm. In lysine and methionine, the particle size of gold was slightly larger. This is because the solubility of gold / lysine complex and gold / methionine complex in water is lower than that of other complexes, and it is impregnated and supported in the state where there is any undissolved residue. This is probably because

<DMTS adsorption experiment method>
The same procedure as in 1 above was performed.

<Result>
The results of Au-supported silica Au / SiO _2- (A) using a gold / β-alanine complex are shown in FIG. 2-1, and the Au-supported silica Au / SiO _2- (GABA) using a gold / 4-aminobutyric acid complex is shown in FIG. The results are shown in FIG. All had good DMTS adsorption capacity.

3. Examination of metals Silver, ruthenium, platinum, and palladium were examined as metals other than gold. Each metal was impregnated and supported on a silica support, and the adsorption performance of DMTS was evaluated by an adsorption experiment.

<Impregnation support on silica support>
Put commercially available metal salts (metal 10 mg equivalent) in a mortar, dissolved in a small amount of water and stirred for mixing therein by adding 990 mg of SiO ₂ 30 min. Then, it dried overnight and baked with air on the conditions shown in the following Table 2, respectively. Silver and platinum were subjected to hydrogen reduction at 300 ° C. for 4 hours after air firing.

<Result>
When the size of the prepared metal particles was measured, the silver particles were 3.0 nm (measured by TEM), the platinum particles were <2.0 nm (measured by XRD), and the palladium particles were 5.2 nm (measured by XRD).

  The results of DMTS adsorption experiments for silver, platinum and palladium are shown in FIGS. All had high adsorption performance.

4). Examination of the carrier The gold particles were impregnated and supported on the silica alumina carrier, the ketjen black carrier and the montmorillonite carrier using the gold / β-alanine complex, and the DMTS adsorption experiment was conducted.

<Aluminum-containing mesoporous silica support>
Place gold / amino acid complex (equivalent to 10 mg of gold) in a mortar, add 0.5 mL of water to dissolve, add 990 mg of silica alumina (aluminum-containing mesoporous silica MCM-41, Sigma-Aldrich), and stir and mix for 30 minutes. did. Thereafter, air calcination was carried out at 300 ° C. for 4 hours without drying to obtain Au-supported aluminum-containing mesoporous silica (Au / Al-MCM-41- (A)). The average particle diameter of the gold particles calculated from the transmission electron microscope (TEM) image was 2.5 nm, and gold particles having a small particle diameter could be supported as in the case of the silica carrier.

<Ketjen black carrier>
A gold / β-alanine complex (equivalent to 5 mg of gold) was placed in a mortar, 0.5 mL of water was added and stirred, 495 mg of Ketjen Black (Lion Corporation) was added thereto, and the mixture was stirred and mixed for 30 minutes. Thereafter, air baking was performed at 300 ° C. for 30 minutes without drying to obtain Au-supported ketjen black (Au / C- (A)). The size of the gold particles supported on the ketjen black support was 4.7 nm, and gold particles having a small particle diameter could be supported as in the case of the silica support.

<Montmorillonite carrier>
A gold / amino acid complex (equivalent to 10 mg of gold) was placed in a mortar, dissolved by adding 0.5 mL of water, 990 mg of montmorillonite (Sigma Aldrich) was added thereto, and the mixture was stirred and mixed for 30 minutes. Thereafter, air baking was performed at 300 ° C. for 4 hours without drying. The gold particle size of the obtained Au-supported montmorillonite (Au / Mont) is about 10 nm (calculated from a transmission electron microscope (TEM) image). Gold particles having a small diameter could be supported.

  The results of DMTS adsorption experiments using Au-supported aluminum-containing mesoporous silica and Au-supported montmorillonite are shown in FIGS. 4-1 and 4-2, respectively. All had good DMTS adsorption capacity.

5. DMTS removal test in sake using adsorbent <Method>
(1) Put 20mL sake and adsorbent into a 20mL glass vial and seal tightly.
(2) Leave at room temperature (about 24 ℃) (24h)
(3) Remove the adsorbent by centrifugation
(4) Measure DMTS concentration of sake (SBSE-GC-MS)

<Result>
Various adsorbents (cerium oxide (first rare element, 173 m ² / g), gold / cerium oxide (prepared by HDP method), silica (Fuji Silysia Q-15), gold / silica (prepared by SG method), oxidation Results of DMTS removal test in sake using titanium (P-25, Nippon Aerosil), gold / titanium oxide (prepared by HDP method), gold / alumina (adjusted by HDP method, alumina is JRC-ALO-5) As shown in Fig. 3, AuSiO ₂ adsorbed DMTS best, but there were other effects, and the DMTS removal rate increased as the amount of adsorbent added increased. There was no effect.

  The performance as an adsorbent was also evaluated for the gold nanoparticle catalyst AuC (made by supporting gold nanoparticles on a ketjen black support), activated carbon, and gold foil manufactured by Halta Gold. The results are shown in Table 4. AuC has a very large DMTS removal effect, but activated carbon alone was also effective. There was no effect on the gold leaf.

The effect of adsorbent treatment on the aroma component (Ginjo aroma component) was investigated. The results are shown in Table 5. AuSiO ₂ hardly adsorbed the aromatic component. AuC adsorbed more than half of isoamyl acetate and ethyl caproate.

6). Sensory evaluation of sake treated with adsorbent <Test method>
(1) Sample preparation As a sake sample, a sake which was stored at 40 ° C for one month was blended with commercial sake from 5 years ago at a ratio of 4: 1. 500 mL of this sake sample was placed in an R bottle, and gold nanoparticle adsorbent or activated carbon prepared using a gold / amino acid complex was added (Table 6). The adsorbent treatment was performed at room temperature for about 24 hours, and the activated carbon treatment was performed at room temperature for about 1 hour. After the treatment, it was pressure filtered through a 0.45 μm filter, transferred to a washed R bottle, and used as a sensory evaluation sample. The same sake sample, which was pressure filtered through a 0.45 μm filter without any additives, was used as a control.

(2) Sensory evaluation The panel was composed of 6 staff members of the Liquor Research Institute who had experience in sensory evaluation (more than 5 years). In order to eliminate the influence of color, amber glass was used as the sample container. The scale evaluation was performed as follows for 4 items of fragrance, 4 items of taste, and 9 items of overall evaluation. For each item, the average value of the evaluation results of 6 persons was calculated, and the presence or absence of a significant difference was examined. JMP ver.9 was used for statistical analysis.

fragrance:
About “Ginjoka”, “Oka”, “Sulfide-like”, “Smelly / Caramel-like / Burn”, it is hardly felt (0 points) to very strong (4 points).
"Tint" (light to dark), "sweet and spicy" (spicy to sweet), "irritant taste / texture" (smooth to rough), and "aftertaste" (mottle to clear) are each rated in 5 levels (all -2 (Point to +2 points)
Comprehensive evaluation:
Excellent (1 point)-5-point evaluation with difficulty (5 points)

  The results are shown in FIG. As for scent and sulfide, the treatment with adsorbent and activated carbon significantly decreased compared to the control (p <0.05). For other items, there was no statistically significant difference between samples. Although there was no statistically significant difference in the overall evaluation, the average value of the adsorbent treatment was the best.

7). DMTS removal test in wine and juice with adsorbent <Method>
Sample preparation:
The wine sample was prepared by diluting a commercially available wine (Kobayashi Winery Domaine Chardonnay) with ultrapure water so that the alcohol content was 10%, and adding DMTS to 1.3 μg / L. The vegetable juice sample was prepared by diluting a commercially available vegetable juice (Kagome vegetable one per day) with ultrapure water and adding DMTS to 1.3 μg / L.

Adsorbent: TN150 and LV430
Two types of Au / SiO ₂ (Au-supported silica, Au average particle size TN150: 4.6 nm, LV430: 3.3 nm) with different production lots were used.

Experimental procedure:
(1) Put 20mL sample and adsorbent into a 20mL glass vial and seal tightly.
(2) Leave at room temperature (about 24 ℃) (24h)
(3) Centrifugation (2600rpm, 10 minutes)
(4) Measure DMTS concentration in supernatant (SBSE-GC-MS)

<Result>
Table 8 shows the measurement results of DMTS concentration of each sample after treatment for 24 hours. The DMTS concentration showed the average value of the measured values in two analyses. In either case, 95% or more of DMTS was adsorbed and removed, and the DMTS concentration could be reduced to less than 0.1 μg / L.

8). DMTS removal test in hexane by adsorbent <Method>
(1) Add DMTS and tridecane as internal standard to hexane
(2) Dilute the solution of (1) with hexane (DMTS concentration: 6.0 ppm)
(3) Add 50.0 mg of Au / SiO ₂ (300 ℃, calcined for 0.5 h, Au average particle size 5.1 nm) to 4.0 mL of the sample in (2)
(4) Measure DMTS remaining amount over time with GC

<Result>
The results of two experiments are shown in FIG. 6-1 (first time), FIG. 6-2 (second time), and Table 9. DMTS in hexane was completely removed in 6 to 24 hours. As a result, it was confirmed that DMTS can be adsorbed and removed from the liquid of the lipophilic organic compound using the fine particles of late transition metal.

Claims (27)

  A method for removing a sulfur-containing compound in a liquid, comprising bringing fine particles of a late transition metal into contact with the liquid.   The method according to claim 1, wherein the fine particles are supported on a carrier.   The said support | carrier is at least 1 sort (s) selected from the group which consists of a silicon material, a carbon material, a metal oxide, clay, a synthetic or natural polymer, carbonate, a porous coordination polymer, and boron nitride. the method of.   The carrier is activated carbon, bentonite, activated clay, diatomaceous earth, silica, silica-alumina, aluminosilicate, chitosan, montmorillonite, phytic acid, agar, gelatin, sodium alginate, carrageenan, microfibrous cellulose, flour, gluten, egg white, The tannin, tannin, polyvinylpyrrolidone, wood chip, collagen, papain, protease, pectinase, hemicellulase, pea protein, β-glucanase, and at least one selected from the group consisting of casein or sodium caseinate The method described.   The late transition metal is at least one selected from the group consisting of gold, silver, platinum, palladium, ruthenium, rhodium, osmium, iridium, iron, cobalt, nickel, copper, and zinc. 5. The method according to any one of 4 above.   The method according to claim 1, wherein the fine particles have an average particle diameter of 50 nm or less.   The method according to any one of claims 1 to 6, wherein the sulfur-containing compound is polysulfide.   The method of claim 7, wherein the polysulfide is dimethyl trisulfide or dimethyl disulfide.   The method according to any one of claims 1 to 8, wherein the liquid is a beverage.   The method of claim 9, wherein the beverage is an alcoholic beverage.   The method according to claim 10, wherein the alcoholic beverage is sake.   The method according to claim 1, wherein the liquid is an organic solvent or a liquid fuel.   A method for reducing sulfide-like off-flavours in a beverage, comprising removing sulfur-containing compounds in the beverage by the method according to any one of claims 9 to 11.   A method for reducing the scent of sake, comprising removing polysulfide in sake by the method according to claim 11.   14. A beverage with reduced sulfide-like off-flavour by the method of claim 13.   The beverage according to claim 15, wherein the beverage is an alcoholic beverage.   Sake with reduced scent by the method according to claim 14.   An adsorbent for sulfur-containing compounds in a liquid, comprising fine particles of late transition metals.   The adsorbent according to claim 18, wherein the fine particles are supported on a carrier.   The adsorbent according to claim 18 or 19, wherein the sulfur-containing compound is polysulfide.   The adsorbent according to claim 20, wherein the polysulfide is dimethyltrisulfide or dimethyldisulfide.   The adsorbent according to any one of claims 18 to 21, wherein the liquid is a beverage.   The adsorbent according to claim 22, wherein the beverage is an alcoholic beverage.   The adsorbent according to claim 23, wherein the alcoholic beverage is sake.   The adsorbent according to any one of claims 18 to 21, wherein the liquid is an organic solvent or a liquid fuel.   26. A liquid container in which the adsorbent according to any one of claims 18 to 25 is immobilized.   A beverage container having the adsorbent according to any one of claims 22 to 24 immobilized thereon.