Method for producing a granular composition containing glutathione

Abstract

To provide a method for producing a glutathione-containing granular composition that is less likely to undergo a deterioration of productivity due to a great rise in the binding force between solid raw materials during granulation.SOLUTION: A method for producing a glutathione-containing granular composition includes a granulation step that uses a stirring granulator 1, which at least has a stirring vessel 10 containing a stirring space 15 defined by a round face 11 and a peripheral wall face 12, and a stirring blade 20 to rotate around the axis perpendicular to the round face 11, and stirs and granulates solid raw materials containing glutathione, accommodated in the stirring space 15 of the stirring vessel 10, by rotating the stirring blade 20 so that its tip speed becomes 250-400 m / min.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for producing a granular composition containing glutathione.

Background Art

[0002] Glutathione is a peptide composed of three amino acids, L-cysteine, L-glutamic acid, and glycine. It exists in many living organisms such as humans, other animals, plants, and microorganisms. It is an important compound for living organisms, such as having an antioxidant effect, a detoxifying effect, and participating in amino acid metabolism.

[0003] In vivo, glutathione exists in either the reduced form of glutathione (N-(N-γ-L-glutamyl-L-cysteinyl)glycine, sometimes hereinafter referred to as "GSH"), in which the thiol group of the L-cysteine residue is reduced to the SH form, or the oxidized form of glutathione (sometimes hereinafter referred to as "GSSG"), in which the thiol groups of the L-cysteine residues of two molecules of GSH are oxidized to form a disulfide bond between the two molecules of glutathione. Glutathione is known to be useful in fields such as fertilizers, pharmaceuticals, and cosmetics.

[0004] Patent Document 1 describes that when granulating a material (solid component) containing glutathione while adding a liquid binder such as water, there are problems such as a significant increase in the binding force (stickiness) of the material, the material adhering to the apparatus during granulation, and the inability to obtain a granulated product with a desired particle size due to an increase in the particle size of the granulated product. And in Patent Document 1, as a means for solving this problem, a method for producing a granular composition containing glutathione is disclosed, which comprises adding a liquid binder to a solid component containing crystalline glutathione and granulating.

[0005] Patent Document 2 describes that in a granulation method using a stirring granulation device, by stirring the stirring blades while maintaining the acceleration at the outer end of the stirring blades substantially constant within a predetermined range, granulated products with a desired particle size can be stably produced without depending on the volume of the granulation tank.

[0006] Patent Document 3 describes a method for determining granulation conditions including the rotation speed and stirring time to obtain a granulated product with a desired average particle size using a stirring granulation device with a known rotation radius of the stirring blades.

[0007] Patent Document 4 describes a method for setting the rotation speed of the stirring blades of a first stirring granulation device provided with stirring blades in a granulation tank, which includes calculating the rotation speed of the stirring blades in the first stirring granulation device from the rotation speed of the stirring blades at which a granulated product with a desired particle size is obtained in a second stirring granulation device having a similar shape with different inner diameters of the granulation tank and radii of the stirring blades, and the rotation radius of the stirring blades of the second stirring granulation device.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0009] In a method for producing a granular composition by granulating a solid raw material containing glutathione, as described in Patent Document 1, there is a problem that during granulation, the binding force between solid raw materials significantly increases, resulting in a decrease in productivity due to the material adhering to the device during granulation and the granulated product becoming coarser. When granulating a granular composition containing glutathione using a stirring granulation apparatus, the problems of adhesion of the material to the wall surface and coarsening of the granulated product are particularly prominent.

[0010] Therefore, in this specification, means for solving the problems of adhesion of the material to the wall surface and coarsening of the granulated product in a method for granulating a granular composition containing glutathione using a stirring granulation apparatus are disclosed.

Means for Solving the Problems

[0011] The inventors of the present invention have found that by using a stirring granulation apparatus equipped with stirring blades in a stirring tank and rotating the stirring blades so that the tip speed becomes 250 to 400 m / min to perform stirring granulation on a solid raw material containing glutathione, the above problems can be solved. Specifically, the following are disclosed in this specification as means for solving the above problems.

[0012] (1) A method for producing a granular composition containing glutathione, comprising: a stirring tank enclosing a stirring space defined by a circular surface and a peripheral wall surface disposed on the periphery of the circular surface; stirring blades disposed on the circular surface and rotating about an axis perpendicular to the circular surface; using at least a stirring granulation apparatus comprising: a granulation step of stirring and granulating a solid raw material containing glutathione accommodated in the stirring space of the stirring tank by rotating the stirring blades so that the tip speed becomes 250 to 400 m / min. (2) The solid raw material is the glutathione; one or more selected from a binder and a water-soluble inorganic salt; and the method according to (1). (3) The method according to (1) or (2), wherein the granulation step includes stirring the solid raw material together with a liquid binder.

Effects of the Invention

[0013] According to the method for producing the granular composition containing glutathione disclosed in this specification, it is possible to suppress a decrease in productivity due to a remarkable increase in the binding force between solid raw materials during granulation.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0015] <Stirring Granulation Apparatus> The stirring granulation apparatus used in the method disclosed in this specification includes a stirring tank that encloses a stirring space defined by a circular surface and a peripheral wall surface disposed on the periphery of the circular surface, and a stirring blade disposed on the circular surface and rotating about an axis perpendicular to the circular surface, and is not particularly limited as long as it includes at least these. For example, the vertical stirring granulation apparatus shown in FIG. 1 or the horizontal stirring granulation apparatus shown in FIGS. 3 and 4 can be used.

[0016] FIG. 1 is a schematic plan view from above the stirring tank 10 of the vertical stirring granulation apparatus 1.

[0017] The stirring tank 10 of the vertical stirring granulation device 1 shown in Fig. 1 encloses a stirring space 15 defined by a circular surface 11 along the horizontal direction and a peripheral wall surface 12 arranged along the vertical direction on the periphery of the circular surface 11. Here, the circular surface 11 is the surface (upper surface) on the side of the stirring space 15 of the bottom 13. The peripheral wall surface 12 is the surface (inner peripheral surface) on the side of the stirring space 15 of the peripheral wall 14. Although not shown, the stirring tank 10 further includes an openable and closable lid, and the opening of the stirring tank 10 facing the circular surface 11 is covered by the lid so as to be openable and closable.

[0018] The stirring blades 20 of the vertical stirring granulation device 1 shown in Fig. 1 are arranged on the circular surface 11 corresponding to the bottom surface of the stirring tank 10 so as to be rotatable about an axis in the vertical direction perpendicular to the circular surface 11. The stirring blades 20 include a plurality of (three in the illustrated embodiment) blade pieces 21. The portion located at the outermost side of the blade piece 21 (the portion farthest from the axis of rotation in the radial direction) is defined as the tip portion 21a of the blade piece 21. In the embodiment using the vertical stirring granulation device 1 shown in Fig. 1, the tip speed of the stirring blades 20 is the circumferential movement speed of the tip portion 21a of the blade piece 21. The stirring blades 20 have a function of flowing the entire raw material in the stirring tank.

[0019] Fig. 2 is a perspective view of the stirring blades 20 provided in the vertical stirring granulation device 1 shown in Fig. 1. The upper surface 21b of the blade piece 21 of the stirring blades 20 is inclined so as to approach the circular surface 11 as it approaches the front in the rotation direction.

[0020] The vertical stirring granulation device 1 shown in Fig. 1 further includes a crushing blade 30 that protrudes from the peripheral wall 14 of the stirring tank 10 into the stirring space 15 and is arranged so as to be rotatable about a horizontal axis. The crushing blade 30 has a function of promoting the mixing of the raw materials and a function of crushing large-sized granulated products and adjusting the particle size.

[0021] Subsequently, with reference to Figs. 3 and 4, the horizontal stirring granulation device 1 will be described. Fig. 3 is a schematic cross-sectional view of the horizontal stirring granulation device 1 along the vertical direction including the rotation axis of the stirring blades 20. Fig. 4 is a schematic cross-sectional view of the horizontal stirring granulation device 1 along the direction perpendicular to the rotation axis of the stirring blades 20 along the line I-I shown in Fig. 3.

[0022] The stirring tank 10 of the horizontal stirring granulating apparatus 1 shown in FIGS. 3 and 4 encloses a stirring space 15 defined by a circular surface 11 along the vertical direction and a peripheral wall surface 12 arranged along the horizontal direction on the periphery of the circular surface 11. Here, the circular surface 11 is the surface on the side of the stirring space 15 of the first side wall 16 arranged along the vertical direction. The peripheral wall surface 12 is the surface (inner peripheral surface) on the side of the stirring space 15 of the peripheral wall 14. The stirring tank 10 further includes a second side wall 17 arranged in the vertical direction and facing the first side wall 16. The peripheral wall 14 connects the peripheries of the first side wall 16 and the second side wall 17. An opening 18 is formed above the peripheral wall 14. Although not shown, the stirring tank 10 further includes an openable and closable lid, and the opening 18 of the peripheral wall 14 is covered by the lid so as to be openable and closable.

[0023] The stirring blade 20 of the horizontal stirring granulating apparatus 1 shown in FIGS. 3 and 4 is arranged on the circular surface 11 of the first side wall 16 of the stirring tank 10 so as to be rotatable about a horizontal axis perpendicular to the circular surface 11. The stirring blade 20 includes a plurality of (three in the illustrated embodiment) blade pieces 22. The blade piece 22 includes a first portion 22-1 extending along the circular surface 11 of the stirring tank 10 in the radial direction from the stirring blade rotation axis 23, a second portion 22-2 extending along the peripheral wall surface 12 of the stirring tank 10 from the radially outer end of the first portion 22-1 toward the second side wall 17, and a third portion 22-3 protruding radially inward from the end of the second portion 22-2 on the side of the second side wall 17. The outermost portion of the blade piece 22 (the portion farthest from the rotation axis in the radial direction) is defined as the tip portion 22a of the blade piece 22. In the embodiment using the horizontal stirring granulating apparatus 1 shown in FIGS. 3 and 4, the tip speed of the stirring blade 20 is the circumferential movement speed of the tip portion 22a of the blade piece 22. The stirring blade 20 has a function of flowing the entire raw material in the stirring tank.

[0024] The horizontal stirring granulation apparatus 1 shown in FIGS. 3 and 4 further includes a disintegrating blade 40 that protrudes into the stirring space 15 from the second side wall 17 of the stirring tank 10 and is arranged to be rotatable about a horizontal axis. The disintegrating blade 40 includes a disintegrating blade rotation axis 41 and a plurality of protrusions 42 that protrude radially from the surface of the disintegrating blade rotation axis 41. The disintegrating blade 40 has a function of promoting the mixing of raw materials and a function of disintegrating large-sized granulated products to adjust the particle size.

[0025] Subsequently, a preferred embodiment of the stirring granulation apparatus, which is common to the vertical stirring granulation apparatus 1 shown in FIG. 1 and the horizontal stirring granulation apparatus 1 shown in FIGS. 3 and 4, will be described.

[0026] The stirring tank can be selected to have an appropriate size according to the volume of the processing raw material. The inner diameter of the peripheral wall surface of the stirring tank can be, for example, in the range of 15 cm to 170 cm.

[0027] The smaller the radial distance (clearance) between the tip of the stirring blade and the peripheral wall surface of the stirring tank, the more efficiently the stirring granulation can be performed. The clearance is preferably 1% or less, more preferably 0.6% or less, preferably 0.2% or more, and more preferably 0.3% or more with respect to the inner diameter of the peripheral wall surface of the stirring tank. Also, the clearance is preferably 1 cm or less, and more preferably 6 mm or less.

[0028] <Glutathione> Glutathione may be reduced glutathione (GSH, N-(N-γ-L-glutamyl-L-cysteinyl) glycine), or oxidized glutathione (GSSG) formed by binding of two molecules of GSH via a disulfide bond, or a mixture of GSH and GSSG. Glutathione is preferably GSSG.

[0029] Glutathione (GSSG or GSH) can include various forms of glutathione, such as a free form not bound to other substances and not ionized, a salt formed by glutathione and an acid or a base, hydrates thereof, and mixtures thereof.

[0030] When using GSSG as glutathione, it may be used as a mixture of GSSG and GSH, but it is preferable that the content of GSSG is relatively higher than that of GSH. More preferably, the total weight of GSSG (weight converted to the free form) with respect to the total weight of GSSG and GSH (weight converted to the free form) is 70% by weight or more in total, more preferably 80% by weight or more, more preferably 90% by weight or more, still more preferably 95% by weight or more, still more preferably 98% by weight or more, and most preferably 100% by weight.

[0031] The salt of GSSG is not particularly limited as long as it is one or more salts acceptable as fertilizers such as ammonium salt, calcium salt, magnesium salt, sodium salt, lithium salt, etc., but preferably one or more salts selected from ammonium salt, calcium salt and magnesium salt. Examples of the GSSG salt include 1-ammonium salt of GSSG, 0.5-calcium salt or 1-calcium salt of GSSG, 0.5-magnesium salt or 1-magnesium salt of GSSG, etc.

[0032] <Granular composition> The use of the granular composition containing glutathione produced by the method disclosed in this specification (the granular composition according to the present disclosure) is not particularly limited, and any use corresponding to the use of glutathione may be sufficient. For example, the granular composition according to the present disclosure can be used for the use of applying to plants. The granular composition according to the present disclosure is obtained by granulating a solid raw material containing glutathione.

[0033] The blending amount of glutathione in the granular composition according to the present disclosure is not particularly limited and can be adjusted according to the use of the granular composition, etc. For example, glutathione can be 0.01% by weight or more, preferably 0.1% by weight or more, more preferably 10% by weight or more, more preferably 15% by weight or more, for example 40% by weight or less, preferably 20% by weight or less with respect to the total amount of the composition. This range is particularly preferable when the granular composition is used for promoting plant growth.

[0034] The shape of the granular composition according to the present disclosure is not particularly limited as long as it is granular, and granules can be exemplified. The granular shape here means that the primary particles of the material are bonded by a granulation operation.

[0035] <Solid raw material> In the present specification, the solid raw material may contain glutathione and may further contain other components.

[0036] The solid raw material preferably contains glutathione and at least one selected from a binder and a water-soluble inorganic salt, and particularly preferably contains a binder and a water-soluble inorganic salt.

[0037] Here, examples of the binder include carboxymethyl cellulose, methyl cellulose, ethyl cellulose, polyvinyl pyrrolidone, pullulan, acrylic acid-based polymers, polyvinyl alcohol, gelatin, agar, gum arabic, powdered gum arabic, xanthan gum, tragacanth gum, guar gum, gellan gum, locust bean gum, pregelatinized starch, macrogol, starch, soluble starch, dextrin, tragacanth, β-glucan, pectin, casein, soy protein, hydroxyethyl cellulose, acetyl cellulose, lignin sulfonic acid, carboxymethyl starch, hydroxyethyl starch, polyvinyl methyl ether, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, shellac, rosin, tall oil, ester gum, polyvinyl acetate, polylactic acid, polyvinyl chloride, polyester, polyurea, polyamide, coumarone resin, biodegradable polymers, paraffin wax, microcrystalline wax, petrolatum, montan wax, carnauba wax, cotton wax, beeswax, lanolin, nonionic surfactants of polymers, anionic surfactants of polymers, cationic surfactants of polymers, amphoteric surfactants of polymers, alginic acid (the above are high molecular compounds), sodium silicate, glycerin, animal and vegetable oils, fats and oils, liquid paraffin, heavy oil, glucose, sucrose, mannitol, sorbitol, nonionic surfactants of non-polymers, anionic surfactants of non-polymers, cationic surfactants of non-polymers, amphoteric surfactants of non-polymers (the above are non-high molecular compounds), etc., and salts thereof. At least one selected from these groups can be used.

[0038] Particularly preferred binders are polymer compound binders. Among them, carboxymethyl cellulose and its salts, polyvinyl alcohol, starch, gum arabic, hydroxyethyl cellulose, lignin sulfonic acid and its salts, and polyethylene glycol are preferably selected. Examples of salts of carboxymethyl cellulose include alkali metal salts such as sodium, potassium, and lithium, and alkaline earth metal salts such as magnesium and calcium. Carboxymethyl cellulose and its salts are considered to contribute to the improvement of the storage stability of glutathione in the composition. By using these binders, sustained release of glutathione may be achieved when the granular composition according to the present disclosure is used for application to plants. When at least one selected from carboxymethyl cellulose and its salts, polyvinyl alcohol, starch, gum arabic, hydroxyethyl cellulose, lignin sulfonic acid and its salts, and polyethylene glycol is used as the binder, the total content relative to the total amount of the granular composition is preferably 0.5 to 5% by weight, more preferably 1 to 3% by weight.

[0039] Another example of a preferred binder is a non-polymeric anionic surfactant, particularly linear alkylbenzene sulfonic acid or its salt. When a non-polymeric anionic surfactant is used as the binder, the total content relative to the total amount of the granular composition is preferably 0.3 to 3% by weight, more preferably 0.5 to 2% by weight.

[0040] As the water-soluble inorganic salt, a water-soluble inorganic salt containing elements useful as fertilizers such as potassium, nitrogen, phosphorus, calcium, and magnesium is particularly preferred. Specific examples of the water-soluble inorganic salt include ammonium sulfate, ammonium dihydrogen phosphate, potassium sulfate, and the like. When ammonium sulfate is used as the water-soluble inorganic salt, the total content based on the total amount of the granular composition is preferably 20 to 50% by weight, more preferably 30 to 40% by weight. When ammonium dihydrogen phosphate is used as the water-soluble inorganic salt, the total content based on the total amount of the granular composition is preferably 10 to 40% by weight, more preferably 15 to 25% by weight. When potassium sulfate is used as the water-soluble inorganic salt, the total content based on the total amount of the granular composition is preferably 10 to 40% by weight, more preferably 20 to 30% by weight.

[0041] The solid raw material may further contain an inorganic carrier, an organic carrier, an excipient, and the like.

[0042] Examples of the inorganic carrier include talc, mica, bentonite, montmorillonite and smectite, clay, kaolin, activated clay, zeolite, diatomaceous earth, perlite, sepiolite, sericite, pumice, silica, white carbon, vermiculite, calcium carbonate, and the like.

[0043] Examples of the organic carrier include dried plant materials such as sawdust, wood chips, soybean powder, corn stalks, and plant fibers, and organic porous carriers such as pulp flock and activated carbon.

[0044] Examples of the excipient include lactose, trehalose, cellulose, and the like.

[0045] <Method for producing granular composition> The method for producing a granular composition containing glutathione disclosed in this specification is a stirring tank enclosing a stirring space defined by a circular surface and a peripheral wall surface disposed on the periphery of the circular surface, a stirring blade disposed on the circular surface and rotating about an axis perpendicular to the circular surface Using a stirring granulation device comprising at least A granulation step of stirring and granulating a solid raw material containing glutathione accommodated in the stirring space of the stirring tank by rotating the stirring blades so that the tip speed becomes 250 to 400 m / min Characterized by including

[0046] The specific embodiment of the stirring granulation device and the tip speed are as described above.

[0047] When the tip speed of the stirring blades of the stirring granulation device is less than 250 m / min, granulated products with a coarse particle size are formed during granulation, resulting in a decrease in productivity. On the other hand, when the tip speed of the stirring blades of the stirring granulation device is 250 m / min or more, coarsening of the particles can be suppressed and productivity can be increased. The tip speed of the stirring blades of the stirring granulation device is more preferably 260 m / min or more.

[0048] When the tip speed of the stirring blades of the stirring granulation device exceeds 400 m / min, the raw material becomes sticky during granulation and the raw material adheres to the wall surface of the stirring tank of the stirring granulation device, resulting in a decrease in productivity. On the other hand, when the tip speed of the stirring blades of the stirring granulation device is 400 m / min or less, adhesion of the raw material to the wall surface of the stirring tank can be suppressed and productivity can be increased. The tip speed of the stirring blades of the stirring granulation device is more preferably 370 m / min or less.

[0049] The average particle size of the solid raw material to be granulated is preferably 55 to 210 μm, more preferably 60 to 200 μm, and even more preferably 71 to 200 μm. The solid raw material having an average particle size within the above range preferably contains 70% by weight or more, and more preferably 80% by weight or more, of particles having a particle size in the range of 20 to 500 μm.

[0050] It is preferable to perform a pulverization step of pulverizing the solid raw material containing glutathione so that the average particle size is within the above range before the granulation step. The pulverization step can be performed using a mixer or the like.

[0051] In this specification, the particle size of the solid raw material refers to the equivalent spherical diameter of the solid raw material determined by the light scattering method (calculating the particle size from the state of light scattering when a laser beam is irradiated on a specimen of the solid raw material). Examples of devices for measuring the particle size by the light scattering method include, for example, the laser diffraction / scattering type particle size distribution measuring device LA-960 manufactured by Horiba, Ltd. The average particle size of the solid raw material refers to the average value calculated by weighting by volume from the particle size distribution of the solid raw material determined by the light scattering method.

[0052] The granulation step is preferably a step of stirring a solid raw material containing glutathione together with a liquid binder. Examples of the liquid binder include liquids such as water and alcohol, as well as molasses and pulp waste liquor. These may be used alone or in combination. Further, the above-mentioned binder may be dissolved in a liquid such as water or alcohol to be used as the liquid binder.

[0053] In the granulation step, while rotating the stirring blade so that the tip speed is within the above range, the treatment time for stirring the solid raw material containing glutathione accommodated in the stirring space of the stirring tank can be appropriately adjusted according to the throughput and the target particle size. Specific treatment times include, for example, 1 to 10 minutes, preferably 2 to 5 minutes.

[0054] When the granular composition produced by the method for producing a granular composition containing glutathione disclosed in this specification is dissolved in water and used for foliar spraying on plants, it needs to be dissolved in water at the time of application, so it is necessary to make the granular composition easy to dissolve. The average particle size of the granular composition used for this application is preferably 50 μm or more in order to avoid deterioration of handling properties due to powdering, and preferably 1000 μm or less in consideration of the time required for dissolution in water.

[0055] It is preferable to perform a drying step of drying the granular composition after the granulation step to dry and remove volatile components derived from the solid raw material and the liquid binder. Further, if necessary, a granular composition having a desired particle size can be separated and recovered by sieving or the like.

Example

[0056] The GSSG-containing granular composition was produced by agitation granulation using an agitation granulation apparatus (SPGJ-2TG type, manufactured by Dalton) having the structure shown in FIG. 1. Agitation granulation was carried out under conditions where the tip speed of the agitation blades was different, and the relationship between the ratio of large particles (>1 mm) in the granular composition, the adhesion in the agitation tank during granulation, and the tip speed of the agitation blades was examined.

[0057] <Raw materials> The following were used as solid raw materials.

[0058] [Table 1] Water was used as the liquid binder.

[0059] <Grinding> The solid raw materials shown in Table 1 were ground with a grinder so that the average particle size became 95 μm. Here, the average particle size is an average value calculated by weighting by volume from the distribution of the sphere-equivalent diameter determined by the light scattering method using a laser diffraction / scattering type particle size distribution measuring apparatus LA-960 manufactured by Horiba, Ltd.

[0060] <Granulation> 500 g of the ground product of the solid raw materials was weighed, 26.5 g of water was added as the liquid binder with an agitation granulator (SPGJ-2TG type, manufactured by Dalton), the agitation blades were rotated so as to have the tip speed shown in the following table, and while the disintegrating blades were rotated at a constant speed, agitation granulation was carried out for 3 minutes. The granular material obtained by agitation granulation was dried with a fluidized bed dryer (F-LABO type, manufactured by NAGATO Electric Works). The obtained dried product was classified by vibration sieving using sieves with an opening of 1 mm and 0.1 mm. The fraction that passed through the sieve with an opening of 1 mm and did not pass through the sieve with an opening of 0.1 mm was recovered as the GSSG-containing granular composition.

[0061] The agitation granulator is a vertical agitation granulation apparatus schematically shown in FIG. 1, the inner diameter of the inner wall surface of the agitation tank is 17 cm, and the radial distance (clearance) between the tip of the agitation blade and the peripheral wall surface of the agitation tank is 1 mm.

[0062] The presence or absence of hard deposits such as gypsum on the wall surface of the stirring tank at the end of stirring granulation was confirmed.

[0063] <Evaluation of productivity> As the proportion of large particles, the proportion (weight %) of the fraction that could not pass through a sieve with an opening of 1 mm with respect to the total amount of the granulated product after drying was determined. When the proportion of large particles was 5% by weight or less, it was evaluated as "〇", and when it exceeded 5% by weight, it was evaluated as "×". Also, when hard deposits such as gypsum were generated on the wall surface inside the stirring tank at the end of stirring granulation, it was evaluated as "×", and when no deposits were generated, it was evaluated as "〇".

[0064] <Results> The tip speed of the stirring blades, the proportion of large particles, and the evaluation results of the adhesion to the stirring tank wall surface are shown in the following table.

[0065]

Table 2

Claims

1. A method for producing a granular composition containing glutathione, comprising: a stirring tank enclosing a stirring space defined by a circular surface and a peripheral wall surface disposed on the periphery of the circular surface; stirring blades disposed on the circular surface and rotating about an axis perpendicular to the circular surface; using a stirring granulation apparatus comprising at least the above; a granulation step of stirring and granulating a solid raw material containing glutathione and having an average particle size of 55 to 210 μm, accommodated in the stirring space of the stirring tank, by rotating the stirring blades so that the tip speed becomes 250 to 400 m / min; the solid raw material contains the glutathione and a binder; the binder is carboxymethyl cellulose or a salt thereof, and linear alkylbenzene sulfonic acid or a salt thereof; the granulation step includes stirring the solid raw material together with a liquid binder; the liquid binder is water; a method.

2. The method according to claim 1, wherein the solid raw material further contains a water-soluble inorganic salt.

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