Purine adsorbent for beer

Abstract

To provide a beer purine body adsorbent that contains an acid-treated product of dioctahedral type smectite-based clay and that has excellent adsorption properties for purine bodies and has a small amount of iron ion elution.SOLUTION: The present invention relates to a beer purine body adsorbent that contains an acid-treated product of dioctahedral type smectite-based clay, in which the ratio of BET specific surface area (A) measured by water vapor adsorption method to BET specific surface area (B) measured by nitrogen adsorption method, (A) / (B), is in the range of 0.90 to 2.80, and the amount of iron ions eluted into 0.1 g / L citric acid aqueous solution is 0.15 mg / g or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a purine adsorbent for beer that can adsorb purines such as xanthine compounds represented by xanthine, and compounds containing adenine or guanine compounds represented by adenine and guanine. [Background technology]

[0002] Alcoholic beverages such as beer contain purines, which can cause gout and other health problems. Therefore, alcoholic beverages with reduced purine content are available for sale.

[0003] Incidentally, xanthine, adenine, and guanine are all compounds that have a purine skeleton (collectively referred to as purines). Zeolites and dioctahedral-type smectite clays (acid clays) are known as adsorbents for removing these from beverages (Patent Document 1).

[0004] However, zeolites have poor selectivity for purines and also adsorb the active ingredients contained in beverages, so they are not used industrially.

[0005] Furthermore, while clays such as acid clay have the advantages of high selective adsorption of purines and being inexpensive, they have the problem of poor filterability. In other words, some of these clays become colloidally dispersed in water, causing clogging of the filter during filtration. To avoid this, centrifugation is performed without filtration, but this results in the loss of active ingredients and increases processing costs.

[0006] Furthermore, Patent Document 1 discloses that activated clay obtained by acid treatment of acid clay exhibits excellent adsorption properties for caffeine (xanthine compounds). For example, in its examples, activated clay manufactured and sold by the present applicant (Galleon Earth NF-2, Galeonite No. 251, manufactured by Mizusawa Chemical Industries, Ltd.) shows high adsorption properties for caffeine.

[0007] Therefore, the present inventors conducted numerous experiments and studies on the adsorption performance of acid-treated materials obtained by acid treatment of dioctahedral-type smectite clay. As a result, they found that acid treatment at a weaker level than that of activated clay, which is used in various applications (hereinafter referred to as weakly acid-treated clay), exhibits superior adsorption performance compared to untreated clay (acid clay), and also has superior filterability, allowing for easy separation from the solution after adsorption treatment (Patent Document 2).

[0008] However, when the aforementioned weakly acid-treated clay was used to remove purines from beer, the beer, after adsorption treatment, had a metallic taste that was not present before the treatment, even though the purines had been removed. Upon investigating the cause, it was determined that the iron contained in the acid-treated clay before acid treatment leached out during the acid treatment, became semi-fixed as exchangeable cations in the clay, and then leached out as iron ions into the beer during the purine adsorption treatment. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Japanese Patent Publication No. 6-142405 [Patent Document 2] Japanese Patent Publication No. 2017-136584 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] The object of the present invention is to provide a purine adsorbent for beer containing an acid-treated product of dioctahedral-type smectite clay, which exhibits excellent adsorption to purines and low iron ion elution. The reason for limiting the use of the adsorbent to purines in beer is to distinguish it from the invention of the adsorbent for purines in liquids other than beer, which was filed on the same day as this invention. Here, "beers" refers to carbonated beverages with a beer-like flavor, and includes fermented beer-flavored beverages obtained by fermenting malt, hops, and water using yeast, as well as non-fermented beer-flavored beverages, non-alcoholic beer-flavored beverages with an alcohol content of less than 1.0(v / v)%, non-alcoholic beer-flavored beverages that do not contain alcohol, and carbonated beverages to which beer flavorings containing esters, higher alcohols, lactones, etc., have been added. [Means for solving the problem]

[0011] The inventors conducted numerous experiments on the amount of iron ions leached from weakly acid-treated clay and, as a result of their investigations, discovered that when the amount of iron ions leached from the weakly acid-treated clay itself is below a certain value, these clays exhibit excellent purine adsorption properties and can reduce the addition of a metallic taste. Based on these findings, the inventors completed the present invention. Here, the iron ions mentioned above may be divalent or trivalent, but in this invention, we do not distinguish between the two and refer to them simply as iron ions.

[0012] The present invention provides a purine adsorbent for beer containing an acid-treated product of dioctahedral-type smectite clay, characterized in that the ratio of the BET specific surface area (A) measured by the water vapor adsorption method to the BET specific surface area (B) measured by the nitrogen adsorption method, (A) / (B), is in the range of 0.90 to 2.80, and the amount of iron ions eluted into a 0.1 g / L citric acid aqueous solution is 0.15 mg / g or less. Here, the amount of iron ions eluted is the amount of iron ions eluted when 1 g of the dioctahedral-type smectite clay is added to a 0.1 g / L aqueous solution of citric acid. A 0.1 g / L citric acid aqueous solution was used because it exhibited a similar amount of iron ion elution as when using liquid beer.

[0013] In the adsorbent of the present invention, (1) The acid-treated product of the dioctahedral-type smectite clay has been further subjected to a treatment to reduce the iron ion content. (2) The amount of interlayer water in the acid-treated product of the dioctahedral smectite-based clay is 30 mg or less per 1 g of the adsorbent excluding adsorbed water and interlayer water. (3) The solid acid amount with Ho ≤ -3.0 is in the range of 0.10 to 0.70 mmol / g-dry clay. (4) The value of the BET specific surface area measured by the nitrogen adsorption method is in the range of 65 to 400 m

[0018] , , / g. (5) The ratio of (A) / (B) is in the range of 1.10 to 2.40. (6) The purine substance is a xanthine compound. is preferred.

[0014] Further, according to the present invention, there is provided a method for producing beers, which is characterized by having a step of adsorbing and removing purine substances in beers by adding the adsorbent.

Advantages of the Invention

[0015] As shown in the examples described later, the adsorbent of the present invention can remove a large amount of purine substances from a purine substance-containing solution equal to or more than that of acid clay by using a small amount, and in addition, can reduce the addition of metallic taste.

[0016] Moreover, since the adsorbent of the present invention is composed of clay subjected to weak acid treatment, it has higher filterability than acid clay and can be easily removed from the solution after the adsorption treatment.

[0017] Therefore, the adsorbent of the present invention can be suitably applied to the removal of purine substances from beers. And since the adsorbent of the present invention can reduce the elution amount of iron ions, it can suppress the influence on the color, flavor and aroma of beverages.

Embodiments for Carrying Out the Invention

[0018] <Weak Acid-Treated Low Iron Ion Clay> The adsorbent of the present invention is a purine adsorbent for beer containing an acid-treated dioctahedral-type smectite clay with an iron ion elution amount of 0.15 mg / g or less, or, if the iron ion elution amount of the acid-treated material exceeds 0.15 mg / g, the acid-treated material is further subjected to an iron ion content reduction treatment to reduce the iron ion elution amount to 0.15 mg / g or less. This is obtained by performing a weaker acid treatment compared to what is generally called activated clay, or by further iron ion content reduction treatment. Therefore, hereafter, the acid-treated material used as a purine adsorbent for beer, or the material after further iron ion content reduction treatment, may be referred to as "weakly acid-treated low iron ion clay."

[0019] The weak acid treatment and iron ion content reduction treatment are primarily aimed at obtaining clay with excellent adsorption and filtration properties for purines by performing the weak acid treatment. If the amount of iron ions eluted exceeds 0.15 mg / g with the weak acid treatment alone, the iron ion content reduction treatment of the acid-treated material is performed to further reduce the amount of iron ions eluted.

[0020] Regarding weak acid treatment, Japanese Patent Publication No. 2009-072759 by the present applicant discloses that an acid-treated product called semi-activated clay, obtained by acid-treating dioctahedral-type clay, is used as a catalyst for polylactic acid depolymerization. However, the weak acid treatment used in the present invention is an even weaker acid treatment than this one.

[0021] Generally, the amount of iron ions leached from clay after acid treatment increases. This is thought to be because some of the iron contained in the clay's framework before acid treatment, or in iron-containing compounds present as impurities, dissolves during the acid treatment, and some of it becomes semi-fixed as exchangeable cations between the clay layers. Furthermore, these semi-fixed iron ions cannot be completely removed by washing after acid treatment, and are thought to leach into the beer during purine adsorption treatment due to the action of organic acids contained in the beer. These leached iron ions are thought to be the cause of the metallic taste in the beer. The amount of iron ions leached depends on the quality of the clay before acid treatment (iron content in the clay, type and amount of impurities, etc.) and the conditions of the acid treatment.

[0022] If the amount of iron ions leached from the clay itself after weak acid treatment is 0.15 mg / g or less, it is not necessary to perform the iron ion content reduction treatment by cation treatment described below. If the amount of iron ions leached exceeds 0.15 mg / g, the solution after adsorption treatment will have a metallic taste, so the iron ion content reduction treatment by cation treatment described below should be performed. Here, it is preferable that the amount of iron ions leached is 0.08 mg / g or less.

[0023] The iron ion content reduction treatment in the present invention is not particularly limited as long as the amount of iron ions eluted from the clay after weak acid treatment is reduced to a desired concentration. For example, it can be carried out by contacting the clay with an aqueous solution containing cations other than iron ions, followed by separation and washing. Through the iron ion content reduction treatment, all or part of the iron ions in the clay are replaced with cations other than iron, and as a result, iron ion content reduction treated clay can be obtained in which the amount of iron ions eluted from the clay is reduced.

[0024] Other cations besides iron ions are not particularly limited as long as they are acceptable in food and beverages, but examples include sodium ions, potassium ions, magnesium ions, calcium ions, and aluminum ions, with sodium ions and potassium ions being preferred among these. For cation treatment, one or more cations other than iron ions can be used.

[0025] In the cation treatment, the above-mentioned cations can be added to the clay in the form of a salt, so that the iron ions in the clay are replaced by the cations. The salt formed by the cations may be either an inorganic salt or an organic salt, but examples include sulfates, chlorides, glucons, ascorbic acid salts, citrates, and lactates, with sulfates being preferred. For cation treatment, one or more inorganic salts and organic salts can be used.

[0026] In the iron ion content reduction treatment, the cations brought into contact with the clay are preferably in the form of an aqueous solution. The concentration of the cations is not particularly limited as long as it can reduce the amount of iron ions eluted from the clay to 0.15 mg / g or less, but is preferably 0.01 to 1000 milliequivalents (hereinafter referred to as "mEq / L"), more preferably 0.1 to 1000 mEq / L, and even more preferably 1 to 1000 mEq / L. When two or more cations or salts are used, it is preferable that the sum of the concentrations of each cation equals the concentration mentioned above.

[0027] In the iron ion content reduction treatment, it is preferable to add an acidic substance so that the pH becomes 5.0 or lower. From the viewpoint of efficiency in reducing iron ion content, it is preferable to add the acidic substance so that the pH becomes 3.0 or lower, and particularly preferable to add it so that the pH becomes 2.0 or lower. If the pH is higher than 5.0, the efficiency of reducing iron ion content will be poor, and sufficient reduction of iron ion content may not be achieved. The acidic substance to be added is not particularly limited, but it is preferable to use an aqueous sulfuric acid solution that is generally used for acid treatment of white clay.

[0028] In the iron ion content reduction treatment, the contact time and contact temperature between the clay and cations are not particularly limited as long as the iron ion content in the clay can be reduced to a desired concentration. However, the contact time is preferably 1 to 48 hours, more preferably 1 to 24 hours, and the contact temperature is preferably 4 to 50°C, more preferably 10 to 30°C. The weakly acid-treated low iron ion clay of the present invention has the characteristics of weakly acid-treated clay described later (for example, the ratio (A) / (B) of the BET specific surface area (A) measured by the water vapor adsorption method to the BET specific surface area (B) measured by the nitrogen adsorption method is 0.90 to 2.80), and the iron ion content reduction treatment is carried out by appropriately controlling the contact time and contact temperature so as not to result in an acid treatment stronger than such a weak acid treatment.

[0029] In the iron ion content reduction treatment, it is desirable to subject the mixture of clay and cations to a solid-liquid separation treatment to remove the iron ions released from the clay and the cations that were not replaced by the iron ions in the clay, and then wash the mixture. Examples of solid-liquid separation treatments include centrifugation and filtration. The washing is not particularly limited as long as it removes the released iron ions and the cations that were not replaced by the iron ions in the clay, but it is preferable to wash the mixture two to three times with pure water.

[0030] In such weakly acid-treated low-iron ion clay, the acid treatment level of the dioctahedral-type smectite clay is very low, so the ratio (A) / (B) of the BET specific surface area (A) measured by the water vapor adsorption method to the BET specific surface area (B) measured by the nitrogen adsorption method is 0.90 or higher, preferably 0.95 or higher, more preferably 1.10 or higher, and particularly preferably 1.20 or higher from the viewpoint of adsorption. It is also 2.80 or lower, and from the viewpoint of filterability, preferably 2.40 or lower.

[0031] It is presumed that such weakly acid-treated, low-iron ion clay exhibits excellent adsorption performance for purines by having a BET specific surface area ratio (A / B) within the above range. In other words, while the nitrogen method (nitrogen method) is the most common method for measuring BET specific surface area, there is also a method using water vapor (water vapor method). According to the Clay Handbook (Third Edition), the nitrogen method measures the total external surface area, including the end faces, per unit mass. In the case of dioctahedral-type smectite clays, which have a three-layer structure, nitrogen molecules do not penetrate between layers at liquid nitrogen temperature, so only the external surface area is measured. On the other hand, in the water vapor method, which uses a polar adsorbent such as water vapor, the adsorbent penetrates sufficiently between the layers of the clay, so the internal surface is measured. Therefore, if A / B is within the above range, it means that the micropores have increased due to very weak acid treatment, and the interlayers of the three basic layers of the smectite clay have expanded. The increase in micropores improves the selective adsorption of purines (especially xanthine compounds such as xanthine), and the expansion of the interlayers of the three basic layers provides appropriate surface hydrophilicity, increasing the adsorption of purines in aqueous and alcoholic solutions. The adsorbent of the present invention (weakly acid-treated low-iron ion clay) having the above A / B values ​​is believed to exhibit extremely high selective adsorption properties for purines because, during the acid treatment process, a balanced expansion of the interlayers between the three basic layers and the formation of micropores within the interlayers occur. For example, in conventional activated clays and semi-activated clays obtained by treating them with strong acids, the interlayer spacing of the three basic layers becomes large, and the micropores formed between the layers are crushed. As a result, the A / B ratio becomes small, and therefore, the purine adsorption properties become extremely low.

[0032] Furthermore, it is presumed that this weakly acid-treated, low-iron ion clay possesses excellent filterability due to the acid treatment it has undergone. Smectite clays (acid clays) that have not been treated with acid have large interlayers containing cations such as Na between the basic layers, which causes them to swell significantly in water. This swelling leads to fine dispersion, resulting in poor filterability. In the case of such weakly acid-treated, low-iron ion clays, some of the basic components in the smectite clay react with the acid, forming a kind of binder that is insoluble in water or alcohol, binding the particles together. This suppresses fine dispersion in solution, resulting in excellent filterability. Therefore, the weaker the acid treatment, the larger the A / B ratio becomes, which may impair the filterability.

[0033] The water contained in clay minerals is classified into adsorbed water adsorbed on the particle surface, interlayer water present in the interlayer region, and structural water referring to hydroxyl groups within the crystal structure. The inventors of this invention have found that, as a result of their study on the interlayer water of weakly acid-treated low-iron ion clay, the adsorption capacity for purines improves when the amount of interlayer water is within a specific range. It is known that adsorbed water desorbs from clay minerals at 60-80°C, and interlayer water desorbs at 90-150°C. Therefore, as described in the examples below, the inventors measured the loss on drying at 80°C (indicating the amount of adsorbed water) and the loss on drying at 150°C (indicating the amount of adsorbed water + interlayer water), and the difference between them was taken as the amount of interlayer water. The amount of interlayer water is shown as the amount per gram of adsorbent (mg / g) excluding adsorbed water and interlayer water.

[0034] In the present invention, the weakly acid-treated low-iron ion clay used as an adsorbent has an interlayer water content of 30 mg / g or less, preferably 20 mg / g or less, and more preferably 15 mg / g or less. Furthermore, the amount of interlayer water is preferably 3 mg / g or more, and particularly preferably 5 mg / g or more. This is because, in order to reduce the amount of interlayer water below the above value, it would inevitably be necessary to perform processing at high temperatures, which would cause the micropores formed between the layers to collapse, impairing the adsorption capacity for purines.

[0035] The mechanism by which adsorption improves when the amount of interlayer water is within a specific range is not yet clear, but it is thought that the removal of water molecules covering the purine adsorption sites from the interlayers and intralayer micropores makes it easier for purines to be adsorbed.

[0036] Furthermore, even if the adsorbent of the present invention, which has a reduced amount of adsorbed water, absorbs moisture again, the absorbed water is retained as adsorbed water, so no new interlayer water is retained, and the adsorption performance is not impaired.

[0037] The weakly acid-treated low-iron ion clay used as an adsorbent in this invention is obtained by a weaker acid treatment compared to what is generally called activated clay. As a result, the Na and Ca components covering Al and Mg, which act as solid acid sites, are removed, and the decrease in solid acid content due to the elution of Al and Mg as the acid treatment progresses is suppressed. Consequently, it exhibits a solid acid content equivalent to or greater than that of what is generally called activated clay obtained by conventional acid treatment, or of acid clay that has not undergone acid treatment. The weakly acid-treated low-iron ion clay preferably has a solid acid content in the range of 0.10 to 0.70 mmol / g-dry clay with Ho ≤ -3.0, meaning it contains a relatively large amount of strong solid acid. That is, its chemical adsorption performance for purines by solid acid is enhanced, and as shown in the examples described later, even when used in small amounts, it can remove a large amount of purines from purine-containing solutions equivalent to or greater than that of conventionally known activated clay or acid clay.

[0038] Here, the amount of solid acid refers to the number of acid sites on the solid surface, and is expressed as the number of acid sites or moles per gram of sample. The strength of the solid acid is indicated by the Hammett acidity function Ho. By titrating with a base such as an amine using an indicator that changes color with a certain Ho, it is possible to quantify the extent to which acid sites of a certain strength or higher are present.

[0039] Furthermore, the weakly acid-treated low-iron ion clay used as an adsorbent in this invention has been weakly acid-treated, and therefore its BET specific surface area by nitrogen method is improved compared to smectite-type clay that has not been acid-treated, preferably 65 to 400 m². 2 / g, particularly preferably 100-400m 2 It falls within the range of / g. However, this weakly acid-treated low-iron ion clay is thought to exhibit high adsorption capacity, although its BET specific surface area ratio (A / B) is lower than that of smectite-type clay that has not been acid-treated.

[0040] Furthermore, the aforementioned weakly acid-treated low-iron ion clay exhibits characteristic X-ray diffraction peaks derived from the crystalline structure of dioctahedral-type smectite clays. For example, in X-ray diffraction measurements, it has a diffraction peak originating from the plane index (06) around 2θ = 62 degrees (d = 1.49~1.50 Å).

[0041] <Manufacturing of weakly acid-treated low-iron ion clay> The weakly acid-treated low-iron ion clay possessing the above-described characteristics is produced by coarsely crushing and kneading dioctahedral-type smectite clay and then acid-treating it with an acidic aqueous solution of a predetermined concentration under predetermined conditions. In other words, this weakly acid-treated low-iron ion clay is obtained in the same manner as semi-activated clay, but it is obtained by acid treatment under milder conditions compared to semi-activated clay.

[0042] The dioctahedral smectite clay used as a raw material is thought to be formed from volcanic rocks and lava that have been metamorphosed under the influence of seawater. The main component, dioctahedral smectite, consists of SiO4 tetrahedral layers, AlO6 octahedral layers, and SiO4 tetrahedral layers. These tetrahedral and octahedral layers are partially isomorphically substituted with dissimilar metals, forming a three-layer structure (unit layer) as the basic structure. Between these three layers, there are cations such as Ca, K, and Na, as well as hydrogen ions and water molecules coordinated to them. Furthermore, some of the Al in the octahedral layers of the basic three-layer structure is substituted with Mg or Fe(II), and some of the Si in the tetrahedral layers is substituted with Al. As a result, the crystal lattice has a negative charge, and this negative charge is neutralized by the metal cations and hydrogen ions present between the basic layers. Examples of smectite-based clays include acid clay, bentonite, and Fuller's earth, each exhibiting different properties depending on the type and amount of metal cations and hydrogen ions present between the basic layers. For example, bentonite has a high amount of Na ions between the basic layers, resulting in a high pH in the dispersion when suspended in water, generally on the highly alkaline side. It also exhibits high swelling in water and even has the property of gelling and solidifying. On the other hand, acid clay has a high amount of hydrogen ions between the basic layers, resulting in a low pH in the dispersion when suspended in water, generally on the acidic side. While it does swell in water, its swelling is generally lower than that of bentonite, and it does not gel.

[0043] In the present invention, the dioctahedral-type smectite clay used in the production of weakly acid-treated low-iron ion clay is not particularly limited, and any of the above-mentioned types can be used. Furthermore, such raw material clays differ depending on the origin of the clay, the place of origin, and even within the same place of origin, the burial site (working face), etc., but generally, they have the following composition in terms of oxides. SiO2; 50~75% by mass Al2O3; 11~25% by mass Fe2O3;2~20% by mass MgO; 2~7% by mass CaO; 0.1~3% by mass Na2O; 0.1~3% by mass K2O; 0.1~3% by mass Other oxides (TiO2, etc.); 2% by mass or less Ig-loss(1050℃);5~11% by mass

[0044] Furthermore, depending on the origin, the raw clay may contain many impurities such as quartz. Therefore, it is preferable to remove as many impurities as possible from the above-mentioned dioctahedral-type smectite clay by performing refining operations such as stone-sand separation, buoyancy separation, magnetic separation, elutriation, and elutriation, as necessary, before performing acid treatment. After such treatment, by performing acid treatment under the mild conditions described below, weakly acid-treated clay with an A / B ratio within the above range can be obtained.

[0045] Acid treatment is carried out by adding the raw clay material to an acidic aqueous solution and mixing and stirring it. While there are no particular limitations on the acidic aqueous solution used in acid treatment, sulfuric acid aqueous solution is generally used from the perspective of cost and environmental impact.

[0046] Furthermore, as already mentioned, this acid treatment is carried out under milder conditions compared to the acid treatments used in the production of conventionally known activated clay and semi-activated clay. For example, when using an aqueous sulfuric acid solution, the amount of aqueous sulfuric acid solution calculated assuming that the water contained in the raw clay also constitutes the aqueous sulfuric acid solution should be 250 to 800 parts by mass per 100 parts by mass of raw clay (as a 110°C dry product), and the acid treatment should be carried out under conditions such that the concentration of the aqueous sulfuric acid solution is about 1 to 15% by mass. The acid treatment can also be heated to about 25 to 95°C if necessary. In this way, the acid treatment should be carried out for a time (about 0.5 to 12 hours, preferably about 0.5 to 8 hours, particularly preferably about 0.5 to 4 hours) such that the specific surface area ratio (A / B) falls within a predetermined range, depending on the composition of the raw materials, the acid concentration of the aqueous acid solution used, the treatment temperature, etc.

[0047] If the amount of iron ions leached from the clay itself after weak acid treatment is 0.15 mg / g or less, there is no need to perform iron ion content reduction treatment by cation treatment. If the amount of iron ions leached exceeds 0.15 mg / g, then iron ion content reduction treatment by cation treatment should be performed.

[0048] The iron ion content reduction treatment is carried out by adding acid-treated clay to a sulfate aqueous solution containing cations such as sodium sulfate, and mixing and stirring it, thereby replacing the iron ions with cations such as sodium.

[0049] Through the acid treatment and iron ion content reduction treatment described above, the ratio A / B of the BET specific surface area measured by nitrogen and the BET specific surface area measured by water vapor, the amount of solid acid, and the value of the BET specific surface area measured by nitrogen fall within the range described above, and the adsorbent of the present invention (weakly acid-treated low iron ion clay) with excellent adsorption performance for purines is obtained.

[0050] Furthermore, the weakly acid-treated low-iron ion clay obtained by the acid treatment and iron ion content reduction treatment described above generally has the following chemical composition in terms of oxides. SiO2; 50~85% by mass Al2O3;8~23% by mass Fe2O3;1~10% by mass MgO; 1~10% by mass CaO; 0.1~2% by mass Na2O; 0.1~3% by mass K2O; 0.1~5% by mass Other oxides (TiO2, etc.); 2% by mass or less Ig-loss(1050℃);4~9% by mass

[0051] After acid treatment or iron ion content reduction treatment, the material is filtered and washed with water, and then dried to adjust the amount of interlayer water. The drying process only needs to bring the amount of interlayer water within a predetermined range, and can be carried out by any method such as oven drying, air drying, or microwave irradiation. The drying temperature varies depending on the drying method, but for example, when drying by standing in an oven, it is preferable to set the oven temperature to 120°C or higher, and more preferably to 140°C or higher, in order to remove interlayer water from the clay minerals. Furthermore, it is preferable to set the oven temperature to less than 200°C, and more preferably to less than 170°C, so as not to crush the micropores formed between the layers. The drying time is not particularly limited as long as the amount of interlayer water is within a specified range, but when drying by standing in an oven, generally two hours or more is sufficient.

[0052] <Purines> In the present invention, the aforementioned weakly acid-treated low-iron ion clay exhibits excellent selective adsorption properties for purines, i.e., compounds having a purine skeleton.

[0053] The purine skeleton is given by the following formula: [ka] As shown above, weakly acid-treated low-iron ion clay exhibits excellent selective adsorption for compounds having a purine skeleton, i.e., compounds having a purine skeleton as a partial structure, and derivatives of such compounds or compounds derived from such compounds.

[0054] One example of a purine is given by the following formula: [ka] In addition to xanthine, which is represented by [formula], hypoxanthine can also be mentioned. In this specification, xanthine, hypoxanthine, and compounds derived from xanthine are collectively referred to as xanthine compounds. The adsorbent of the present invention exhibits excellent selective adsorption to xanthine compounds and is suitable as an adsorbent for xanthine compounds, and is particularly suitable as an adsorbent for xanthine.

[0055] Furthermore, adenine and guanine are also purines. Compounds derived from adenine or guanine include purine nucleosides (adenosine, guanosine) composed of adenine or guanine and ribose, and purine nucleotides (adenylic acid, guanylic acid) that also contain phosphate as a component. Other organic compounds derived from adenine or guanine, though not limited to these, include deoxyguanosine, deoxyguanosine triphosphate, nicotinamide adenine dinucleotide (NAD), flavin adenine dinucleotide (FAD), inosine, and inosinic acid. In this specification, the above-mentioned adenine or guanine, and compounds derived from adenine or guanine, are collectively referred to as adenine or guanine compounds. The adsorbent of the present invention exhibits selective adsorption to adenine and guanine, and therefore also exhibits excellent selective adsorption to adenine or guanine compounds, making it suitable as an adsorbent for such compounds.

[0056] In this invention, "beers" refers to carbonated beverages having a beer-like flavor, and includes not only fermented beer-flavored beverages described later, but also non-fermented beer-flavored beverages, non-alcoholic beer-flavored beverages with an alcohol content of less than 1.0(v / v)%, non-alcoholic beer-flavored beverages that do not contain alcohol, and carbonated beverages to which beer flavorings have been added. In this specification, "beer" may refer to a fermented beer-flavored beverage obtained by fermenting malt, hops, water, etc., using yeast, or it may refer to a non-fermented beer-flavored beverage that does not undergo a fermentation process. Here, "malt" refers to germinated and dried seeds of grains such as barley, wheat, rye, oats, oats, pearl oats, and oats, with the roots removed, and the origin and variety may be any of these. In one embodiment of the present invention, it is preferable to use barley malt. Barley malt is one of the most commonly used malts as an ingredient in beer-flavored beverages in Japan. There are various types of barley, such as two-row barley and six-row barley, and any of them may be used. In addition to regular malt, colored malts may also be used. When using colored malts, different types of colored malts may be used in appropriate combinations, or one type of colored malt may be used. The malt ratio (the ratio of all malts used) is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 48% by mass or more, even more preferably 50% by mass or more, and particularly preferably 55% by mass or more. It may also be 60% by mass or more, 65% by mass or more, 66% by mass or more, 67% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 100% by mass. By increasing the malt ratio, it is possible to produce a beer-flavored beverage in which the rich flavor derived from malt and the umami of barley can be felt more strongly. Here, the malt ratio refers to the value calculated in accordance with the Liquor Tax Law and the Interpretation Circular on Laws and Regulations Related to Liquor Administration, which came into effect on April 1, 2018. Furthermore, when the proportion of malt used is reduced, the amount of other raw materials (carbon sources, nitrogen sources) that yeast can utilize may be increased. Examples of carbon sources that yeast can utilize include monosaccharides, disaccharides, trisaccharides, and their sugar solutions, while examples of nitrogen sources include yeast extract, soy protein, malt, soybeans, yeast extract, peas, wheat malt, ungerminated grains, and their decomposition products. Examples of ungerminated grains include ungerminated barley, wheat, rye, oats, oats, pearl oats, oats, rice (white rice, brown rice, etc.), corn, sorghum, potatoes, beans (soybeans, peas, etc.), buckwheat, sorghum, millet, and barnyard millet. Starches obtained from these grains, or their extracts, may also be used. Furthermore, a beer-flavored beverage according to one aspect of the present invention may be an ale-flavored beverage brewed through a fermentation process using top-fermenting yeast (such as Saccharomyces), or a lager-flavored beverage or a pilsner-flavored beverage brewed through a fermentation process using bottom-fermenting yeast (such as Saccharomyces).

[0057] Furthermore, the beer-like beverages may be alcohol-containing beer-flavored beverages with an alcohol content of 1.0 (v / v)% or higher, or non-alcoholic beer-flavored beverages with an alcohol content of less than 1.0 (v / v)% or non-alcoholic beer-flavored beverages that do not contain alcohol. In this specification, alcohol content refers to the alcohol content (v / v%) in the beverage and can be measured by any known method, for example, by a vibrating densimeter. Specifically, a sample is prepared by removing carbon dioxide from the beverage by filtration or ultrasound, and the sample is then distilled by direct flame, the density of the obtained distillate at 15°C is measured, and the specific gravity can be calculated by converting it using "Table 2 Conversion Table for Alcohol Content, Density (15°C) and Specific Gravity (15 / 15°C)," which is an appendix to the National Tax Agency's prescribed analytical method (National Tax Agency Instruction No. 6 of 2007, revised June 22, 2007). For low concentrations of alcohol content less than 1.0%, commercially available alcohol measuring devices or gas chromatography may be used.

[0058] In carbonated beverages to which the beer flavorings of this specification are added, examples of beer flavorings include isoamyl acetate, ethyl acetate, n-propanol, isobutanol, acetaldehyde, ethyl caproate, ethyl caprylate, isoamyl propionate, linalool, geraniol, citral, 4-vinylguaiacol (4-VG), 4-methyl-3-pentenoic acid, 2-methyl-2-pentenoic acid, 1,4-cineole, 1,8-cineole, 2,3-diethyl-5-methylpyrazine, γ-decanolactone, γ-undecalactone, ethyl hexanoate, ethyl 2-methylbutyrate, ethyl n-butyrate, myrcene, citral, limonene, maltol, ethylmaltol, and phenylacetic acid. In the flavoring treatment, one or more beer flavorings can be added to the aforementioned beers.

[0059] A method for producing a fermented beer-flavored beverage, which is a type of beer according to one aspect of the present invention, comprises the following steps (1) to (3). • Process (1): The raw materials undergo saccharification treatment, boiling treatment, and solid content removal treatment, at least Another process is performed to obtain the pre-fermentation liquid. Step (2): A step to obtain cooled pre-fermentation liquid by cooling the pre-fermentation liquid obtained in step (1). • Step (3): Add yeast to the pre-fermentation liquid obtained in Step (2) to carry out alcoholic fermentation. Approximately.

[0060] <Process (1)> Step (1) is a step in which various raw materials are subjected to at least one of the following treatments: saccharification, boiling, and solid content removal, in order to obtain a pre-fermentation liquid. For example, when malt is used as one of the raw materials, water and the various raw materials including malt are put into a mashing kettle or mashing tank, and if necessary, an enzyme agent that promotes the change of components derived from the raw materials may be added before fermentation. Examples of such enzyme preparations include amylase, protease, deaminase, polyphenol oxidase, glucanase, xylase, pectinase, cellulase, lipase, and glucosidase. Furthermore, enzyme preparations falling under Article 3, "7. Articles not treated as raw materials for alcoholic beverages," of the Liquor Tax Law and related liquor administration regulations (amended June 27, 2018), specifically "(3) The following enzyme preparations added during the brewing process for the purpose of rationalizing brewing," can be included. Adding these enzyme preparations allows for efficient adjustment of the component composition of the resulting fermented beer-flavored beverage. Other ingredients besides malt may include hops, preservatives, sweeteners, water-soluble dietary fiber, bittering agents or bittering agents, antioxidants, flavorings, acidulants, and salts. These may be added before the saccharification process, during the saccharification process, or after the completion of the saccharification process. They may also be added after the subsequent alcohol fermentation process.

[0061] A mixture of various raw materials is heated to saccharify the starch in the raw materials, and a saccharification treatment is performed. The temperature and time of the saccharification treatment are preferably adjusted as appropriate, taking into consideration the type of malt used, the malt ratio, water and other raw materials besides malt, the type and amount of enzyme used, and the concentration of the original extract of the final beverage. In one embodiment of the present invention, the temperature of the saccharification treatment is preferably 55 to 75°C, and the time of the saccharification treatment is preferably 30 to 240 minutes. After the saccharification treatment, the mixture is filtered to obtain a saccharified liquid.

[0062] Furthermore, it is preferable to boil this saccharified liquid. When using hops, bittering agents, etc. as raw materials during this boiling process, it is preferable to add them. Hops, bittering agents, etc. may be added between the start and end of boiling of the saccharified liquid. Alternatively, instead of the above-mentioned saccharified liquid, a pre-fermentation liquid may be prepared by adding hops, bittering agents, etc. to malt extract and warm water, and then boiling it.

[0063] Furthermore, if malt is not used as a raw material, a liquid sugar solution may be prepared by mixing a carbon source-containing liquid sugar, a nitrogen source as an amino acid-containing raw material other than malt or barley, hops, preservatives, sweeteners, water-soluble dietary fiber, bittering agents or bittering agents, antioxidants, flavorings, acidulants, salts, etc. with warm water, and then boiling the liquid sugar solution to prepare the pre-fermentation liquid. If hops are used, they may be added before boiling, or they may be added between the start and end of boiling of the liquid sugar solution.

[0064] <Process (2)> Step (2) is the process of cooling the pre-fermentation liquid obtained in step (1) to obtain a cooled pre-fermentation liquid. After the boiling process is complete, it is transferred to a whirlpool and cooled to 0-20°C. After cooling, solid components such as coagulated proteins may be removed to adjust the original extract concentration. Through such processing, a cooled pre-fermentation liquid is obtained.

[0065] <Process (3)> Step (3) is the step of adding yeast to the pre-fermentation liquid obtained in step (2) to carry out alcoholic fermentation. The yeast used in this step can be appropriately selected considering the type of fermented beer-flavored beverage to be produced, the desired flavor and fermentation conditions, etc., and either top-fermenting yeast or bottom-fermenting yeast may be used.

[0066] Yeast can be added to the raw materials as a yeast suspension, or a slurry obtained by concentrating the yeast by centrifugation or sedimentation can be added to the pre-fermentation liquid. Alternatively, the supernatant can be completely removed after centrifugation and then added. The amount of yeast to be added to the stock solution can be set as appropriate, for example, 5 × 10 6 cells / mL ~ 1 × 10 8 The concentration is approximately cells / mL.

[0067] The conditions for alcoholic fermentation, such as fermentation temperature and duration, can be set as appropriate. For example, fermentation may be carried out at 8-25°C for 5-10 days. The temperature (increase or decrease) or pressure of the fermentation liquid may be changed during the fermentation process. The degree of fermentation of the appearance of the fermented beer-flavored beverage can be adjusted by appropriately setting the type, amount, and timing of addition of polysaccharide-degrading enzymes such as transglucosidase, and can also be adjusted by changing the temperature (increase or decrease) or pressure of the fermentation liquid during the fermentation process. After the completion of this process, the yeast may be removed using a filter, and water, flavorings, acidulants, colorants, and other additives may be added as needed. After these steps, processes known to those skilled in the art for the manufacture of fermented beer-flavored beverages, such as storage and filtration, may be carried out.

[0068] <Process (4)> Step (4) is a purine adsorption and removal step in the method for producing a fermented beer-flavored beverage, which further reduces the purine content by adsorbing and removing purines. In step (4), the adsorbent of the present invention (weakly acid-treated low-iron ion clay) is added to the pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage to adsorb and remove purines. The specific method of adding the adsorbent is to add it through any piping provided in the manufacturing process of the fermented beer-flavored beverage or through a tank located along the piping. The method of adding the adsorbent is not particularly limited; for example, it can be added through an inlet provided in the piping, or through an inlet provided in the tank. The adsorbent may be added as is, or it may be added after being dissolved in a medium such as degassed water. As for the specific method of adsorption and removal, known methods such as adsorption and removal using a filtration filter can be employed. The purine removal step may be performed, for example, simultaneously with or after step (1), simultaneously with or after step (2), simultaneously with or after step (3), during the storage step, or during the filtration step, but it is preferable to perform it after the completion of step (2), and more preferably after the completion of step (3). Furthermore, the purine removal step may be performed multiple times.

[0069] The amount of adsorbent added is not particularly limited and can be adjusted according to the purine content of the pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage. Furthermore, the adsorbent can be added continuously or intermittently, but it is preferable to add it continuously (proportionally) so that the adsorbent concentration remains constant relative to the flow rate of the pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage. In the case of proportional addition, the amount of adsorbent added (the concentration of the adsorbent upon contact with the pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage) is calculated using the following formula 1. Amount added (ppm) = Amount of adsorbent added per unit time (g / h) / (Flow rate of pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage at the addition point (HL / h) × 100) ... (Equation 1)

[0070] The amount of adsorbent added to the pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage may be, for example, 50 ppm or more, more preferably 60 ppm or more, 70 ppm or more, 80 ppm or more, 90 ppm or more, 100 ppm or more, 120 ppm or more, 140 ppm or more, 160 ppm or more, 180 ppm or more, 200 ppm or more, 220 ppm or more, 240 ppm or more, 260 ppm or more, 280 ppm or more, or 300 ppm or more. Alternatively, it may be 5000 ppm or less, more preferably 4500 ppm or less, 4000 ppm or less, 3500 ppm or less, 3000 ppm or less, 2500 ppm or less, 2000 ppm or less, or 1500 ppm.

[0071] In the purine removal process, the contact time between the pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage and the adsorbent can be set arbitrarily, for example, 5 minutes to 7 days, 10 minutes to 3 days, 10 minutes to 180 minutes, or 10 to 40 minutes. Here, the contact time in the purine removal process is calculated using the following formula 2 when the adsorbent is added via piping. Therefore, the contact time can be adjusted by the distance from the adsorbent addition point to the centrifuge, and by the flow rate of the pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage. Contact time (s) = Distance from the adsorbent addition point to the centrifuge (m) / Flow rate of the pre-fermentation liquid, fermentation liquid, or fermented beer-flavored beverage (m / s) ... (Equation 2)

[0072] Alternatively, purine nucleosidase treatment may be performed before the adsorption treatment. In purine nucleosidase treatment, purine nucleosidase can be applied to the fermentation raw material liquid before fermentation or to the fermentation liquid after fermentation to convert adenosine and guanosine in the solution into free purine groups, and at least a portion of these free purine groups can be converted into xanthine, which is a free purine group that is not assimilated by yeast. By performing a purine removal step after this process, xanthine, among the purines, can be preferentially adsorbed and removed by the adsorbent of the present invention, thereby reducing the purine content in the final fermented beer-flavored beverage. There is no restriction on the timing of the purine nucleosidase treatment as long as it is performed before the adsorption treatment; for example, it may be performed simultaneously with or after the completion of step (1), or simultaneously with or after the completion of step (3).

[0073] The fermented beer-flavored beverage obtained in this way is filled into designated containers and distributed to the market as a product. The method for packaging fermented beer-flavored beverages is not particularly limited, and any packaging method well known to those skilled in the art can be used. In the packaging process, the fermented beer-flavored beverage is filled and sealed into a container. Any form or material of container may be used in the packaging process. Examples of containers include cans, bottles, PET bottles, or kegs, but cans, bottles, and PET bottles are preferred, particularly from the viewpoint of ease of transport.

[0074] <Application> The weakly acid-treated low-iron ion clay used as an adsorbent in this invention not only exhibits excellent selective adsorption of purines, but also reduces the elution of iron ions that can affect the flavor of beverages, and is therefore used as an adsorbent for removing purines from beer. For example, it is used by adding 0.001 to 10 parts by mass once or multiple times during or after the manufacturing process of beer. More specifically, the aforementioned weakly acid-treated low-iron ion clay is particle-sized to a suitable average particle size (for example, about 10 to 300 μm) and mixed with the beverage. Alternatively, it can be processed into a column or filter and passed through, and in either method, the adsorbent is separated from the beverage after adsorbing xanthine and the like. [Examples]

[0075] The excellent effects of the present invention will be explained by the following examples.

[0076] (1) BET specific surface area (B) by nitrogen adsorption method Measurement was carried out 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.

[0077] (2) BET specific surface area (A) by water vapor adsorption method Measurement was carried out by the water vapor adsorption method using BELSORP MAX manufactured by Nippon Bell Co., Ltd., and calculated by the BET method. The pretreatment was performed at 150 °C for 2 hours.

[0078] (3) Amount of interlayer water Weighed about 2 g of the adsorbent powder and allowed it to stand and dry in an oven at 80 °C for 2 hours. Then weighed again to obtain the weight loss on drying at 80 °C based on the wet weight W 80 (%). Weighed about 2 g of the adsorbent powder and allowed it to stand and dry in an oven at 150 °C for 2 hours. Then weighed again to obtain the weight loss on drying at 150 °C based on the wet weight W 150 (%). The following formula: W L =(W 150 -W 80 ) / (100 - W 150 ) × 1000 was used to obtain the amount of interlayer water per 1 g of the adsorbent excluding adsorbed water and interlayer water W L (mg / g).

[0079] (4) Amount of solid acid The amount of solid acid with Ho ≤ -3.0 was measured by the n-butylamine titration method. The sample was measured for a sample that had been dried at 150 °C for 3 hours in advance {Reference: "Catalysis", Vol. 11, No. 6, P210 - 216 (1969)}.

[0080] (5) Xanthine adsorption test In this example, the xanthine adsorption capacity was defined as the amount of xanthine (mg) adsorbed by 1 g of the adsorbent (anhydrous) from a xanthine solution with a concentration of 5 mg / L, and measured and calculated by the following method. First, distilled water was added to ethanol (99.5%) (reagent grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) to prepare a 5 vol% ethanol aqueous solution, and sulfuric acid was added to adjust the pH to 3.4. Xanthine (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in the resulting solution to obtain a 5 mg / L xanthine solution. 30 g of this 5 mg / L xanthine aqueous solution was weighed into a 50 ml Erlenmeyer flask and left overnight in a constant temperature bath maintained at 2°C. 0.015 g of adsorbent (0.05 mass relative to the solution) was added, and the mixture was returned to the 2°C constant temperature bath and stirred for 15 minutes using a magnetic stirrer placed inside the bath. Next, the entire volume of liquid in the flask was transferred to a 50 ml centrifuge tube and processed using a centrifuge (Kubota Corporation 6000) at 3000 rpm for 15 minutes. The supernatant of the processed liquid was filtered through a membrane filter with a pore size of 0.45 μm to obtain the sample solution. The absorbance of the sample solution at a wavelength of 267 nm was measured using a spectrophotometer (JASCO Corporation V-560). Then, the amount of xanthine remaining in the sample solution was calculated using a calibration curve that showed the relationship between xanthine concentration and absorbance at a wavelength of 267 nm, and the xanthine adsorption rate (%) was calculated from the amount of xanthine before the addition of the adsorbent.

[0081] (6) Iron ion elution test In this example, the amount of iron ions eluted was defined as the amount of iron (mg) eluted from 1 g of adsorbent (anhydrous) in a 0.1 g / L concentration citric acid aqueous solution, and was measured and calculated using the method described below. First, citric acid (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in distilled water to obtain a 0.1 g / L concentration citric acid aqueous solution. 30 g of this 0.1 g / L citric acid aqueous solution was weighed into a 50 ml Erlenmeyer flask and left overnight in a constant temperature bath maintained at 2°C. 0.09 g of adsorbent (0.3 mass%) was added, and the mixture was returned to the 2°C constant temperature bath. The mixture was then stirred for 3 hours using a magnetic stirrer placed inside the constant temperature bath. Next, the entire volume of liquid in the flask was transferred to a 50 ml centrifuge tube and processed using a centrifuge (Kubota Corporation, model 6000) at 3000 rpm for 15 minutes. The supernatant of the processed liquid was filtered through a membrane filter with a pore size of 0.45 μm to obtain the sample solution. The iron ion concentration in the sample solution was measured using an atomic absorption spectrophotometer (Hitachi High-Tech Science Corporation, model Z-2010), and the amount of iron eluted was calculated.

[0082] Table 1 shows the physical properties and various adsorption test results for the adsorbent powders shown in the following examples and comparative examples.

[0083] (Example 1) Dioctahedral-type smectite clay from Tainai City, Niigata Prefecture, was coarsely crushed, dried in an oven at 110°C for 12 hours, then pulverized and classified to obtain clay powder. 220 mL of a 10% by mass sulfuric acid aqueous solution was placed in a beaker and heated to 90°C. 30 g of the clay powder was added to the solution, and the mixture was stirred while maintaining the temperature at 90°C, and acid treatment was carried out for 30 minutes. After the acid treatment was completed, the acid-treated material was filtered and washed with water. Furthermore, 220 mL of a 400 mEq / L sodium sulfate aqueous solution, adjusted to pH 1.0 by adding sulfuric acid, was placed in a beaker. The entire amount of the filtered cake after washing was then added to this solution, and the mixture was stirred at room temperature for 24 hours to reduce the iron ion content. After the iron ion content reduction treatment was completed, the treated material was filtered and washed with water. The filtered cake was then left to stand and dry in an oven at 150°C for 12 hours, crushed, and classified to obtain an adsorbent powder.

[0084] (Example 2) The adsorbent powder was obtained in the same manner as in Example 1, except that the procedure in Example 1 was scaled up 90,000 times.

[0085] (Example 3) An adsorbent powder was obtained in the same manner as in Example 1, except that a 400 mEq / L sodium sulfate aqueous solution was replaced with a 400 mEq / L potassium sulfate aqueous solution.

[0086] (Example 4) An adsorbent powder was obtained in the same manner as in Example 1, except that a 400 mEq / L aqueous solution of sodium sulfate was replaced with a 400 mEq / L aqueous solution of magnesium sulfate.

[0087] (Example 5) The adsorbent powder was obtained in the same manner as in Example 1, except that the pH was changed from 1.0 to 3.0.

[0088] (Example 6) An adsorbent powder was obtained in the same manner as in Example 2, except that the sulfuric acid concentration was changed to 15% by mass, the weight of clay added was increased by 1.5 times, and the sodium sulfate aqueous solution concentration was changed to 450 mEq / L.

[0089] (Comparative Example 1) An adsorbent powder was obtained in the same manner as in Example 1, except that the 400 mEq / L sodium sulfate aqueous solution was replaced with a sulfuric acid aqueous solution.

[0090] (Comparative Example 2) An adsorbent powder was obtained in the same manner as in Example 1, except that the 400 mEq / L aqueous sodium sulfate solution adjusted to pH 1.0 was replaced with distilled water.

[0091] [Table 1]

[0092] In the adsorbents of Examples 1 to 6, the ratio (A) / (B) was in the range of 0.96 to 2.15, the adsorption rate of xanthine (a purine) was in the range of 86 to 99%, and the amount of iron ions eluted (Fe eluted) was low, ranging from 0.02 to 0.09 mg / g. In the adsorbents of Comparative Examples 1 and 2, the ratio (A) / (B) was in the range of 1.36 to 1.70, and the xanthine adsorption rate was in the range of 83 to 90%, but the iron ion elution amount was 0.17 to 0.70 mg / g. Furthermore, beers from which purines were removed using the adsorbents of Comparative Examples 1 and 2 had a metallic taste. Furthermore, 3,000 ppm of the adsorbents from Examples 1, 3, 4, and 5 and Comparative Examples 1 and 2 were added to fermented beer-flavored beverages with a malt ratio of less than 50%. The mixtures were kept warm at 0-4°C and subjected to stirring for 3 hours. The adsorbents were then removed by centrifugation, and the xanthine adsorption rate and iron ion elution rate were calculated. As a result, it was confirmed that the adsorbents from Examples 1, 3, 4, and 5 had a higher xanthine adsorption rate and lower iron ion elution rate compared to the adsorbents from Comparative Examples 1 and 2.

Claims

1. A purine adsorbent for beer containing an acid-treated product of dioctahedral-type smectite clay, wherein the ratio of the BET specific surface area (A) measured by the water vapor adsorption method to the BET specific surface area (B) measured by the nitrogen adsorption method, (A) / (B), is in the range of 0.90 to 2.

80. The acid-treated product of the aforementioned dioctahedral-type smectite clay is further subjected to a treatment to reduce the iron ion content using an aqueous sodium sulfate solution. A purine adsorbent for beer, characterized in that the amount of iron ions eluted into a 0.1 g / L citric acid aqueous solution is 0.03 mg / g or less.

2. The adsorbent according to claim 1, wherein the amount of interlayer water in the acid-treated dioctahedral-type smectite clay is 30 mg or less per gram of adsorbent excluding adsorbed water and interlayer water.

3. The adsorbent according to claim 1 or 2, wherein the amount of solid acid with Ho ≤ -3.0 is in the range of 0.10 to 0.70 mmol / g-dry clay.

4. The BET specific surface area value measured by the nitrogen adsorption method is 65 to 400 m². ２ An adsorbent according to any one of claims 1 to 3, wherein the amount is in the range of / g.

5. The adsorbent according to any one of claims 1 to 4, wherein (A) / (B) is in the range of 1.10 to 2.

40.

6. The adsorbent according to any one of claims 1 to 5, wherein the purine is a xanthine compound.

7. A method for producing beer, characterized by having a purine adsorption and removal step in which an adsorbent according to any one of claims 1 to 6 is added to adsorb and remove purines from the beer.

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