JP7273529B2 - Theanine scavenger - Google Patents

Description

TECHNICAL FIELD The present invention relates to a scavenger for theanine, one of amino acids contained in tea leaves.

Theanine, ie, γ-glutamylethylamide, is abundant in tea leaves and is known as one of the umami components of tea. It has also been reported that theanine has a relaxing effect, an anti-stress effect, and an effect of improving sleep quality. For example, Patent Document 1 proposes the use of theanine as a brain function improving agent. It is also sold as an additive to various supplements and beverages.

The above Patent Document 1 also describes that theanine is biosynthesized by culturing plants or microorganisms, extracted from tea leaves, and chemically synthesized. However, obtaining theanine by biosynthesis, chemical synthesis, or the like results in high costs, so it is industrially desired to obtain theanine by extraction from tea leaves.

By the way, Patent Literature 2 discloses green tea containing catechin and theanine at high concentrations by purifying green tea (aqueous extract of tea components) using activated carbon, acid clay, and activated clay. As can be understood from this, acid clay (dioctahedral smectite clay) and activated clay (acid-treated acid clay) do not have an adsorptive property for theanine.

In addition, the present applicant has previously found that the BET specific surface area (A) measured by the water vapor adsorption method and the BET specific surface area (B) measured by the nitrogen adsorption method, which are composed of acid-treated dioctahedral smectite clay, and A theanine adsorbent having a ratio (A/B) in the range of 0.90 to 5.00 was proposed (Japanese Patent Application No. 2017-148422).
Such an adsorbent was developed based on the knowledge that an acid-treated dioctahedral smectite clay obtained by adjusting the degree of acid treatment can effectively adsorb theanine from an aqueous solution of theanine. Compared to untreated dioctahedral smectite clay (so-called acid clay), highly acid-treated dioctahedral smectite clay (so-called activated clay), or silica, etc. It is capable of effectively adsorbing theanine.

Japanese Patent Application Laid-Open No. 05-068578 JP 2009-274969 A

As a result of further research on the theanine adsorptivity of the acid-treated dioctahedral smectite clay, the present inventors found that the BET specific surface area (A) measured by the water vapor adsorption method and the BET specific surface area (A) measured by the nitrogen adsorption method A porous inorganic material having a ratio (A/B) to a BET specific surface area (B) of a certain value or more effectively adsorbs theanine from a theanine solution in which theanine is dissolved in an appropriate polar organic solvent, and furthermore , found that the adsorbed theanine can be easily collected with water.

Accordingly, it is an object of the present invention to provide a theanine scavenger which can effectively adsorb theanine from a solution of theanine in an organic solvent and can easily scavenge the adsorbed theanine with water. .

According to the present invention, the ratio (A/B) between the BET specific surface area (A) measured by the water vapor adsorption method and the BET specific surface area (B) measured by the nitrogen adsorption method is in the range of 0.15 or more. The theanine from an organic solvent solution, which is composed of a porous inorganic material, wherein the porous inorganic material is dioctahedral smectite or a calcined product thereof, an acid-treated dioctahedral smectite, silica, or silica magnesia A theanine scavenger is provided.

The theanine scavenger of the present invention preferably has a BET specific surface area of 10 m ² /g or more as measured by a nitrogen adsorption method.

According to the present invention, a polar organic solvent having a solubility parameter (SP value) of 8.3 or more is prepared,
mixing the theanine-containing substance with the polar organic solvent to elute theanine into the polar organic solvent;
By mixing the theanine scavenger with the polar organic solvent in which the theanine is eluted, the theanine is adsorbed on the theanine scavenger,
Next, by solid-liquid separation, the theanine scavenger to which theanine is adsorbed is recovered,
mixing the recovered theanine scavenger with water to elute the theanine from the scavenger to obtain an aqueous theanine solution;
There is provided a method for collecting theanine characterized by:

In such a collection method,
(1) using an alcohol as the polar organic solvent;
(2) using tea leaves or tea extract as the theanine-containing substance;
is preferred.

In the present invention, the BET specific surface area (A) measured by the water vapor adsorption method (hereinafter sometimes referred to as water vapor BET) and the BET specific surface area (B) measured by the nitrogen adsorption method (hereinafter referred to as nitrogen BET A porous inorganic material having a ratio (A/B) of 0.1 or more is used as a scavenger for theanine. A porous inorganic material having such a BET ratio exhibits a large water vapor BET value comparable to or higher than that of nitrogen BET. This indicates that this porous inorganic material is hydrophilic.
In the present invention, by putting such a hydrophilic porous inorganic material into and mixing with a solution of theanine in an organic solvent, theanine in the solution can be effectively adsorbed. Since theanine is water-soluble, it is considered that theanine dissolved in an organic solvent is easily adsorbed to a hydrophilic porous inorganic material.
This also means that even dioctahedral-type smectites, which have low adsorption to theanine in an aqueous solution, can effectively adsorb theanine by extracting theanine from theanine-containing substances using an organic solvent. which is a great advantage of the present invention. That is, as long as a predetermined BET ratio is satisfied, the dioctahedral smectite can be used as it is as a scavenger for theanine without being subjected to a particular acid treatment.
After solid-liquid separation, the scavenger of the present invention in which theanine is adsorbed from the organic solvent solution of theanine is put into water and stirred and shaken as appropriate to easily release the adsorbed theanine, Thereby, theanine can be collected in the form of an aqueous solution.

As described above, according to the present invention, by selecting a porous inorganic material exhibiting a predetermined hydrophilicity (BET ratio), even a material that did not exhibit adsorption to theanine in an aqueous solution can be organically It exhibits good adsorption properties for theanine in the solvent, making it possible to effectively collect theanine.

<Porous inorganic material>
In the present invention, the porous inorganic material used for collecting theanine has a ratio (A/ B) is 0.1 or more, particularly 0.2 or more. The larger the BET ratio, the larger the water vapor adsorption amount, which means that the hydrophilicity is increased. That is, as explained above, the porous inorganic material having such a BET ratio is capable of capturing, ie, adsorbing water-soluble theanine in an organic solvent. For example, when the BET ratio is smaller than the above range, the hydrophilicity of the porous inorganic material is poor, and although theanine present in the organic solvent can be adsorbed, it is not desorbed and can be collected efficiently. Can not.

The BET ratio of the porous inorganic material used in the present invention is preferably 10 or less, particularly 3 or less. This is because if the BET ratio becomes larger than necessary, the filterability tends to decrease.

Further, such a porous inorganic material preferably has a BET specific surface area of 10 m ² /g or more, particularly in the range of 20 to 700 m ² /g, as determined by the nitrogen adsorption method, provided that the BET ratio is within the above range. . That is, the BET specific surface area by the water vapor adsorption method is measured by, for example, water vapor penetrating and being retained inside the particles of the inorganic material (for example, between layers or in the pores). In the nitrogen adsorption method for measurement, liquid nitrogen does not permeate the inside of the particles as much as water vapor. Therefore, the BET specific surface area determined by the nitrogen adsorption method indicates a substantial surface area, and depends on the ability of the porous inorganic material to trap (adsorb) theanine and the value of the BET specific surface area. For example, when the BET specific surface area value determined by the nitrogen adsorption method is excessively low, the contact area with theanine tends to be low and the theanine-scavenging ability in an organic solvent tends to be low. Further, when the BET specific surface area obtained by the nitrogen adsorption method becomes extremely large, the particle diameter becomes fine and the ratio of the BET specific surface area obtained by the water vapor adsorption method greatly decreases, making it impossible to satisfy the above BET ratio.

In the present invention, any porous inorganic material can be used as long as it has the BET ratio as described above. Typical examples include dioctahedral smectite, silica magnesia and silica. .

The above-mentioned dioctahedral smectite is believed to have been metamorphosed _{from volcanic} rock, lava, etc. under the influence of seawater _. The basic structure (unit layer) is a three-layer structure (unit layer) in which the tetrahedral layer and the octahedral layer are partially isomorphically substituted with dissimilar metals. There are cations such as Ca, K, and Na, hydrogen ions, and water molecules coordinating with them. In addition, Mg and Fe (II) are substituted for part of Al in the octahedral layer of the basic three-layer structure, and Al is substituted for part of Si in the tetrahedral layer, so the crystal lattice is negative. It has an electric charge, and this negative electric charge is neutralized by metal cations and hydrogen ions existing between the basic layers. Such dioctahedral smectites include acid clay, bentonite, Fraser's earth, etc., and exhibit different characteristics depending on the type and amount of metal cations present between the basic layers, the amount of hydrogen ions, and the like. For example, bentonite has a large amount of Na ions existing between the basic layers, and therefore, the pH of the dispersion dispersed in water is high, and is generally on the high alkaline side. Furthermore, it exhibits the property of gelling and consolidating. On the other hand, acid clay has a large amount of hydrogen ions existing between the basic layers, and for this reason, the pH of the dispersion dispersed in water is low, generally on the acid side, and shows swelling in water. However, compared with bentonite, its swelling property is generally low and gelation does not occur.

In the present invention, the dioctahedral smectite (hereinafter sometimes simply referred to as smectite clay) used as the porous inorganic material is not particularly limited as long as it has the above-described BET ratio. Any of the various types described above can be used. Such smectite-based clays generally have the following compositions in terms of oxides, although they vary depending on the origin of the clay, the place of production, and even in the same place of production, the burial place (face).
SiO ₂ ; 50 to 75% by mass
Al ₂ O ₃ ; 11 to 25% by mass
Fe ₂ O ₃ ; 2 to 20% by mass
MgO; 2 to 7% by mass
CaO; 0.1 to 3% by mass
Na ₂ O; 0.1 to 3% by mass
K ₂ O; 0.1 to 3% by mass
Other oxides (TiO _2, etc.); 2% by mass or less Ig-loss (1050°C); 5 to 11% by mass

In addition, smectite-based clay may contain a large amount of impurities such as quartz depending on the place of production. Therefore, the above-mentioned smectite-based clay is subjected to refining operations such as sediment separation, flotation beneficiation, magnetic beneficiation, elutriation, wind elutriation, etc., if necessary, to remove impurities as much as possible before use.

For smectite clay that does not satisfy the predetermined BET specific surface area, the BET specific surface area is increased to the range specified in the present invention by performing a known acid treatment to the extent that the peculiar crystal structure is not destroyed. can be made
Such an acid treatment is carried out by adding smectite clay to an acid aqueous solution and mixing and stirring. The aqueous acid solution used for the acid treatment is not particularly limited, but an aqueous sulfuric acid solution is generally used from the viewpoint of cost, environmental impact, and the like. Such an acid treatment removes the Na and Ca contents in the smectite clay. Further, as the acid treatment progresses, the Al and Mg contents are eluted, the surface area and pores increase, and the BET specific surface area increases. resulting in an increase in

The smectite-based clay obtained by such an acid treatment is derived from the plane index (06) generated near the X-ray diffraction peak (for example, 2θ = 62 degrees (d = 1.49 to 1.50 Å) peculiar to the clay. It is called activated clay, semi-activated clay, etc., depending on the degree of acid treatment. For example, activated clay is obtained by acid treatment with a high-concentration acid aqueous solution for a long time, and semi-activated clay is obtained by using a low-concentration acid aqueous solution or shortening the treatment time. It is also called weakly acid treated clay if it is acid treated under weaker acid treatment conditions. In any case, the acid treatment increases the BET specific surface area and the BET ratio determined by the nitrogen adsorption method. In some cases, the crystalline structure peculiar to smectite clay is destroyed, so care must be taken.

The dioctahedral smectite and the acid-treated product described above can be used by adjusting the particle size to a particle size suitable for collecting theanine, which will be described later, by pulverization, classification, or the like.
In addition, sintered products of such dioctahedral smectites and acid-treated products can also be used as porous inorganic materials as long as the predetermined BET ratio is not impaired. Such calcination is usually performed at 1000° C. or less, which causes a decrease in the pore volume that causes a decrease in the BET ratio due to thermal shrinkage, etc., but has the advantage of being easy to handle because the particle strength and filterability are improved. be.

Silica-magnesia used as the porous inorganic material in the present invention is particles in which silica particles and magnesia particles are integrally combined, and silica particles and magnesia particles are particles at a very fine level (for example, nano-level). They are in close contact with each other and have an integrated structure without being separated. That is, since silica-magnesia is not a reaction product of silica and magnesia like magnesium silicate, but a hydrophilic silica component exists in the form of independent particles, it is possible to satisfy the BET ratio described above. It can be used as a porous inorganic material for collecting theanine.

In the present invention, the silica-magnesia used as the porous inorganic material has a silica component and a magnesia component represented by the following formula (1):
R=Sm/Mm (1)
In the formula, Sm is the content (% by mass) of the silica component in terms of _SiO2 ,
Mm is the content (% by mass) of the magnesia component in terms of MgO,
It is preferable that the mass ratio (R) represented by is contained at a ratio of 0.1≦R≦3.5.
That is, since silica and magnesia are present in the above-mentioned ratio, the composite and integrated state is stably maintained. For example, when the above mass ratio (R) exceeds 3.5 or is less than 0.1, silica or magnesia tends to fall off, and therefore, the ability to capture theanine becomes unstable and tends to vary. Because it becomes

Furthermore, in such silica-magnesia, since the silica component and the magnesia component are not separated from each other and are tightly complexed, the pH (25°C) of the 5 mass% concentration suspension is usually 6.0. ~10.0.

In the present invention, the silica-magnesia composite particles used are prepared by homogeneously mixing silica (A) and magnesia or a hydrate thereof (B) in the presence of water to form an aqueous slurry (homogeneous mixing). , then aging, and further removing the moisture.
The amount ratio of silica (A) and magnesia or its hydrate (B) is set so that the mass ratio (R) represented by the above formula (1) is 0.1 to 3.5. do it.
As a tendency, as the content of silica increases, the hydrophilicity increases and the BET ratio tends to increase, and when the content of silica decreases, the BET ratio tends to decrease. Therefore, in consideration of this point, it is possible to obtain silica-magnesia that satisfies the predetermined BET ratio by conducting laboratory experiments in advance and setting the above mass ratio (R).

As the raw material silica (A), an amorphous hydrous type is preferable, and it may be produced by either a gel method or a sedimentation method, but one with small primary particles is preferable. In order to obtain silica magnesia having a predetermined BET ratio, it is preferably 40 m ² /g or more, particularly 140 m ² /g or more.
As magnesia or its hydrate (B), those having small crystallites and not undergoing carbonation over time are preferred. For example, magnesia powder having a BET specific surface area of 2 m ² /g or more, preferably 20 m ² /g or more, particularly preferably 50 m ² /g or more is used.

When the silica (A) and magnesia or its hydrate (B) are homogeneously mixed in the presence of water, for example, in water, silica (silicon dioxide), which is one of the raw materials, is formed into colloidal particles or fine agglomerated particles ( primary to secondary particles). When magnesia (magnesium oxide) on the other hand is put into water and stirred or pulverized, it hardly dissolves. crystals) are disintegrated or exfoliated to form fine particles of magnesia (magnesium oxide) and/or magnesium oxide hydrate and dispersed in water.

In the preparation of the aqueous slurry in the presence of water as described above, there are no restrictions on the order of adding the raw materials (A) and (B) and water, but if aggregation or gelation (thickening) occurs, the above-mentioned There is a possibility that the progress of fine particle formation (nanoparticle formation) and integrated composite formation may be hindered. For this reason, the lower the solid content concentration of the aqueous slurry, the better. On the other hand, from the standpoint of productivity and economy, a higher solid content concentration is preferable. Therefore, the solid content concentration is preferably 3 to 15% by mass, particularly 8 to 13% by mass.

In the aging step, water is removed from the slurry in which these fine particles are uniformly dispersed, and as the solid content concentration increases, the silica particles (A) and the magnesia particles (B) gradually or rapidly form. They come close to each other and form an integrally composited form (completion of integrally composited) without chemical bonding that accompanies atomic exchange or recombination, and the desired silica-magnesia composite particles are obtained.

The homogenous mixing and aging as described above are performed at 100°C or less, preferably at 50 to 97°C. Performing at 50 to 79°C effectively prevents gelation and enables complex integration in a short time. It is suitable for doing.

Homogenous mixing and aging are generally carried out with stirring in a stirring tank equipped with a stirring blade, but can also be carried out with pulverization or dispersion using a wet ball mill or colloid mill.
Further, it is necessary to carry out homogenous mixing and aging for at least 0.5 hours, although this varies depending on the temperature, the amount of slurry charged, and the like. In addition, the higher the temperature, the higher the fluidity of the nanoparticles and the more efficient the homogenization. Mixing and aging are generally carried out for 1 to 24 hours, particularly 3 to 10 hours.

After aging, water is removed by evaporative drying using a spray dryer, slurry dryer, or the like. Drying may be performed using a fluid bed dryer or the like. At this time, the hydration of the raw material (B) is at least partially or completely eliminated.

As described above, silica-magnesia composite particles having a moisture content of, for example, 10% by mass or less, and having silicon dioxide (silica) particles and magnesia particles, which are raw material particles, closely combined by dehydration, are formed into granules, It can be obtained in the form of powder, cake or nodules. These are pulverized, classified, or molded, if necessary, and used as a particle shape suitable for collecting theanine, which will be described later.
Such silica magnesia is commercially available, for example, from Mizusawa Chemical Industry Co., Ltd. under the trade names of "Mizukalife F-1G" and "Mizukalife F-2G".

Furthermore, silica can also be used as the porous inorganic material in the present invention. As such silica, various types are known, but so-called wet-process silica obtained by reacting an alkali silicate such as sodium silicate with an acid is preferably used. For example, dry silica or fumed silica obtained by burning silicon tetrachloride or the like is extremely fine and has an extremely large nitrogen adsorption BET specific surface area, but has almost no pores and has a predetermined BET It cannot be used in the present invention because the ratio cannot be satisfied.

In the present invention, in addition to the above, various minerals and inorganic compounds such as stevensite and magnesium silicate can be used as long as the porous material has a BET ratio within a predetermined range. Dioctahedral smectite, its acid-treated (or calcined) product, and silica magnesia are most preferably used in terms of trapping properties.
In order to adjust the pH of the liquid when desorbing theanine, which will be described later, an additive such as aluminum sulfate may be mixed and used as long as it does not adversely affect the ability to collect theanine.

<Collection of theanine>
In the present invention, theanine is extracted using an organic solvent from theanine-containing substances typified by tea leaves, and the above-described porous inorganic material is added to the organic solvent solution of theanine, mixed and stirred to extract theanine. can be collected.
That is, theanine is water-soluble and, as mentioned above, the porous inorganic material used has a high affinity for water. Therefore, theanine present in the organic solvent solution easily migrates from the organic solvent to the porous inorganic material side, and as a result, theanine can be effectively adsorbed and collected. For example, when a porous inorganic material is added to an aqueous solution of theanine obtained by extracting theanine with water and mixed and stirred, the amount of theanine adsorbed is extremely small, but theanine is extracted using an organic solvent. In this case, the amount of theanine adsorbed increases remarkably.
Interestingly, when activated carbon (with a very low BET ratio) is used, theanine is adsorbed, but unlike the porous inorganic material of the present invention, the amount of theanine desorbed is extremely small. is. In the case of activated charcoal, the hydrophilicity is extremely low, so it is thought that water is difficult to penetrate into the activated charcoal and theanine is not released.

In the present invention, the organic solvent used has a solubility parameter of 8.3 or more, particularly in the range of 10-20. This solubility parameter is an index called the solubility parameter (δ) calculated by the calculation method proposed by Small, and is calculated from the molecular volume and the molar attraction constant for the atoms or atomic groups that make up the molecule and their bond types. (σ=(ΔE/V) ^1/2 ; PAJ Small: J. Appl Chem., 3, 71 (1953)). The solubility parameter is also called the SP value ^. It is widely used, and the smaller the difference in this value, the higher the affinity and compatibility between the two substances.
That is, the solvent whose SP value is within the above range is known as a polar organic solvent, and by using such a polar organic solvent, it is possible to extract theanine from theanine-containing substances such as tea leaves. . In addition, if the SP value is excessively high, even if theanine can be extracted, it is highly hydrophilic, and as a result, it is difficult for the porous inorganic material to adsorb theanine in this polar organic solvent. becomes. Further, those having an SP value lower than the above range (eg n-hexane, SP value 7.3) have poor theanine extractability and cannot be used in the present invention.

Incidentally, the polar organic solvents preferably used in the present invention are as follows. The values in parentheses are SP values (unit: (cal/ml) ^1/2
).
Acetone (9.4)
Dioxane (9.8)
Isopropyl alcohol (10.2)
Ethanol (11.2)
Dimethylformamide (11.5)
Acetonitrile (11.8)
Methanol (12.9)
In the present invention, alcohols (specifically, isopropyl alcohol, ethanol and methanol) are preferably used, and ethanol is most preferably used, because they are easy to handle and readily available.

The above-mentioned polar organic solvents, especially alcohols, often contain water and are often used as a mixed solvent with water. , is preferably suppressed to 50% or less. This is because when a large amount of water is mixed, the adsorption of theanine to the porous inorganic material is inhibited.

In the present invention, the amount of the polar organic solvent used is, for example, 50 ml or more, usually about 100 to 500 ml, per 1 g of tea leaves.
In addition, the extraction of theanine using a polar organic solvent can be performed by adding a theanine-containing substance such as tea leaves to the polar organic solvent at a temperature below room temperature (for example, about 15 to 30° C.) and holding the mixture with stirring for 1 hour or longer. As a result, theanine contained in the tea leaves can be extracted into the polar organic solvent in an amount of, for example, about 10 to 100 mg/L.
Furthermore, a commercially available tea extract (eg, Theafran manufactured by Itoen Co., Ltd. or Sanfenon manufactured by Taiyo Kagaku Co., Ltd.) can also be used instead of tea leaves.

The above-described porous inorganic material may be added to the polar organic solvent containing theanine extracted as described above, and mixed and stirred in the same manner at room temperature (about 15 to 30 ° C.), especially heating etc. is necessary. not. The amount of the polar organic solvent used is usually about 10 to 30 L per 1 g of theanine present in the polar organic solvent. The above can be adsorbed on the porous inorganic material.

After the theanine is adsorbed on the porous inorganic material as described above, the porous inorganic material on which theanine is adsorbed is subjected to solid-liquid separation by centrifugation, filtration, or the like.
The solid-liquid separated porous inorganic material is put into, for example, 30 ml or more of pure water per 1 g of the porous inorganic material, and stirred by ultrasonic vibration or the like, thereby being adsorbed and held by the porous inorganic material. Theanine can be eluted into pure water. Theanine collected in pure water is collected by being concentrated by heating or the like, and is used for applications such as supplements and pharmaceuticals.

According to the present invention, even a porous inorganic material that cannot effectively adsorb theanine from an aqueous solution of theanine can adsorb and capture theanine by extracting theanine with a polar organic solvent. It has the great advantage of being able to collect
Alternatively, by using a means of extracting theanine using a polar organic solvent, absorbing and collecting the theanine with a porous inorganic material, and then eluting theanine from the porous inorganic material using pure water, the theanine It is also a great advantage of the present invention that impure organics that are co-extracted can be eliminated and highly pure theanine can be collected.

The excellent effects of the present invention will be explained by the following experimental examples.

(1) BET specific surface area (B) by nitrogen adsorption method
It was measured by the nitrogen adsorption method using TriStar 3000 manufactured by Micromeritics, and calculated by the BET method. The pretreatment was performed at 150° C. for 2 hours.

(2) BET specific surface area (A) by water vapor adsorption method
BELSORP manufactured by Bell Japan Co., Ltd. was used for measurement by the water vapor adsorption method, and calculated by the BET method. The pretreatment was performed at 150° C. for 2 hours.

(3) Theanine adsorption test First, L-theanine (manufactured by Wako Pure Chemical Industries, Ltd.) was dissolved in 99.5% ethanol (reagent grade 1, manufactured by Wako Pure Chemical Industries, Ltd.) to obtain a concentration of 51 mg/L of theanine. A solution was obtained.
30 g of this theanine solution was collected in a 50 ml capacity centrifuge tube, 0.5 g of adsorbent (1.7% by mass to the liquid) was added, and the mixture was shaken by a shaker (SA300 manufactured by Yamato Scientific Co., Ltd., shaking speed 5). Shake for 5 hours.
Next, the supernatant of the liquid was treated with a centrifugal separator (7780II, manufactured by Kubota Corporation) for 10 minutes at a centrifugal acceleration of 10,000 rpm, and filtered through a membrane filter (C045A025A, manufactured by ADVANTEC) to obtain a liquid (sample liquid). The absorbance of light with a wavelength of 201 nm of the sample solution was measured with a spectrophotometer (UV-2600 manufactured by Shimadzu Corporation). At this time, in order to subtract the influence of soluble salts, etc. of the adsorbent, the absorbance when 0.5 g of adsorbent was added to 30 g of ethanol in which theanine was not dissolved in advance and the same operation was performed was subtracted from the absorbance of the sample solution. It was used as the corrected absorbance of the liquid. Then, the residual amount of theanine in the sample solution was calculated using a calibration curve prepared in advance showing the relationship between the theanine concentration and the absorbance of light with a wavelength of 201 nm.

(4) Theanine desorption test 30 g of ion-exchanged water was added to the adsorbent (theanine-containing adsorbent) remaining after collecting the sample solution in the above adsorption test, and a shaker (SA300 manufactured by Yamato Scientific Co., Ltd., shaker) was added. The mixture was shaken at speed 5) for 2.5 hours.
Next, the supernatant of the liquid was treated with a centrifugal separator (7780II, manufactured by Kubota Corporation) for 10 minutes at a centrifugal acceleration of 10,000 rpm, and filtered through a membrane filter (A045A025A, manufactured by ADVANTEC) to obtain a liquid (sample liquid). Corrected absorbance was measured in the same manner as in the adsorption test, and the amount of theanine in the sample solution was measured. The amount of theanine desorbed was obtained by subtracting the amount of theanine remaining from the adsorption test solution from the amount of theanine.

(5) Particle size Measurement was performed using a laser diffraction/scattering particle size distribution analyzer LA-960 manufactured by Horiba Ltd. with an ethanol solvent. Ultrasonic dispersing was performed at an intensity of 1 for 1 minute. The sample refractive index was set to a real term of 1.49 and an imaginary term of 0.10i. Algorithm option uses LA-950 compatibility (standard), distribution form is manual (convergence strength 300), and 10% diameter (D10), 50% diameter (D50), and 90% diameter (D90) based on volume are measured. bottom.

Tables 1 to 3 show the physical properties and various adsorption/desorption test results of the adsorbents shown in the following examples and comparative examples.

(Example 1)
Acid clay Mizuka Ace #20 manufactured by Mizusawa Chemical Industry Co., Ltd.;

(Example 2)
Dioctahedral smectite clay from Tsuruoka City, Yamagata Prefecture was dried (110° C.), pulverized and classified to obtain clay powder. 220 ml of a 5% by mass sulfuric acid aqueous solution was placed in a beaker and heated to 90°C. 30 g of clay powder was added thereto, and the mixture was stirred while maintaining the liquid temperature at 90° C., and subjected to acid treatment for 30 minutes. After the acid treatment, the acid-treated product was filtered and washed with water, and the washed filter cake was dried at 110° C., pulverized and classified to obtain weak acid-treated clay powder (D10: 5.6 μm, D50: 31.0 μm). 9 μm, D90: 147.5 μm).

(Example 3)
Activated clay galleon earth V2 manufactured by Mizusawa Chemical Industry Co., Ltd.

(Example 4)
Dioctahedral type smectite clay powder Mizuka Binder Z manufactured by Mizusawa Chemical Industry Co., Ltd.;

(Example 5)
A calcined clay powder obtained by calcining the clay powder obtained in Example 1 at 300° C. for 2 hours in an electric furnace (1500 Plus manufactured by Denken-High Dental Co., Ltd.).

(Example 6)
A fired clay powder obtained by changing the firing temperature of Example 5 to 500°C.

(Example 7)
A fired clay powder obtained by changing the firing temperature of Example 5 to 700°C.

(Example 8)
A fired clay powder obtained by changing the firing temperature of Example 5 to 900°C.

(Example 9)
Aluminum-added clay powder obtained by mixing 8% by mass of an aluminum sulfate aqueous solution (8% concentration) with dioctahedral smectite clay produced in Tsuruoka City, Yamagata Prefecture, drying at 110°C, pulverizing and classifying.

(Example 10)
Mizusawa Chemical Industry Co., Ltd. silica magnesia formulation Mizukalife F-1G.

(Example 11)
Silica gel Mizukasorb C-1 manufactured by Mizusawa Chemical Industry Co., Ltd.;

(Example 12)
Powder (D10: 4.5 μm, D50: 17.9 μm, D90: 31.7 μm) obtained by adjusting the particle size of Mizusawa Kagaku Kogyo Co., Ltd. acid clay Mizuka Ace #20.

(Example 13)
Powder (D10: 15.7 μm, D50: 55.1 μm, D90: 70.0 μm) obtained by adjusting the particle size of Mizusawa Kagaku Kogyo Co., Ltd. acid clay Mizuka Ace #20.

(Example 14)
700 g of dioctahedral smectite clay pellets from Tainai City, Niigata Prefecture were put into 1000 ml of a 5% by mass sulfuric acid aqueous solution heated to 90°C. The mixture was stirred while maintaining the liquid temperature at 90° C., and acid treatment was performed for 30 minutes. After acid treatment, the pellets washed with water were dried at 110° C., pulverized and classified to obtain weakly acid-treated clay powder (D10: 4.6 μm, D50: 41.1 μm, D90: 97.0 μm).

(Example 15)
Powder (D10: 3.4 μm, D50: 12.6 μm, D90: 24.2 μm) obtained by adjusting the particle size of the weak acid-treated clay obtained in Example 14.

(Comparative example 1)
Commercially available activated carbon powder.

Claims (5)

A porous inorganic material having a ratio (A/B) of the BET specific surface area (A) measured by the water vapor adsorption method and the BET specific surface area (B) measured by the nitrogen adsorption method in the range of 0.15 or more. A theanine scavenger from a theanine organic solvent solution, wherein the porous inorganic material is dioctahedral smectite or a calcined product thereof, an acid-treated dioctahedral smectite, silica, or silica magnesia. The theanine scavenger according to claim 1 , wherein the BET specific surface area measured by a nitrogen adsorption method is in the range of 10 m ² /g or more. Prepare a polar organic solvent with a solubility parameter (SP value) of 8.3 or more,
mixing the theanine-containing substance with the polar organic solvent to elute theanine into the polar organic solvent;
The theanine is adsorbed on the theanine scavenger by mixing the theanine scavenger according to claim 1 or 2 with the polar organic solvent in which the theanine is eluted,
Next, by solid-liquid separation, the theanine scavenger to which theanine is adsorbed is recovered,
mixing the recovered theanine scavenger with water to elute the theanine from the scavenger to obtain an aqueous theanine solution;
A method for collecting theanine, characterized by: The method for collecting theanine according to claim 3 , wherein alcohol is used as the polar organic solvent. The collection method according to claim 3 or 4 , wherein tea leaves or tea extracts are used as the theanine-containing substance.