Oxygen absorber composition and oxygen absorber packaging

Abstract

This oxygen absorber composition contains an iron powder (A), an alkali metal halide or an alkaline earth metal halide (B), activated carbon (C), and an inorganic powder filler (D), wherein the apparent density of the inorganic powder filler (D), excluding the iron powder (A), the alkali metal halide or the alkaline earth metal halide (B), and the activated carbon (C), is between 1.10 g / cm3 and 2.90 g / cm3 inclusive, and the inorganic powder filler (D) content is 50 to 300 parts by mass to 100 parts by mass of the iron powder (A).

Description

Oxygen absorber composition and oxygen absorber package

[0001] The present invention relates to an oxygen absorber composition and an oxygen absorber package.

[0002] Oxygen absorbers utilizing the oxidation reaction of iron powder (hereinafter referred to as iron-based oxygen absorbers) have been proposed. Commercially available oxygen absorbers (e.g., trade name "AGELESS" manufactured by Mitsubishi Gas Chemical Co., Inc.) are sealed in gas barrier containers together with other items such as food and medicine, and are therefore widely used to remove oxygen from the containers and maintain the quality and freshness of the items.

[0003] Iron-based oxygen absorbers are classified into "moisture-dependent" oxygen absorbers that start absorbing oxygen by utilizing moisture evaporated from the preserved material, and "self-reacting" oxygen absorbers that already contain the moisture necessary for the iron's oxygen absorption reaction in the oxygen absorber composition. "Moisture-dependent" oxygen absorbers are used for foods that contain a particularly large amount of moisture, such as rice cakes and fresh noodles. Furthermore, cooked rice that can be stored for a long period of time has recently become available on the market, and oxygen absorbers that are compatible with such foods with high water activity are being developed.

[0004] For example, Patent Document 1 discloses a microwave-resistant cooked rice package in which cooked rice having a viable cell count and pH within a specific range is housed and sealed in a container with low oxygen permeability together with a microwave-resistant oxygen absorber package. Patent Document 1 lists oxygen absorbers whose main ingredient is ascorbic acid or a salt thereof, isoascorbic acid or a salt thereof, or iron powder.

[0005] Japanese Patent Application Publication No. 02-128663

[0006] As described above, "moisture-dependent" oxygen absorbers absorb oxygen by utilizing moisture evaporated from the preserved food, and are therefore suitable for foods with high water activity. However, because rice cakes and cooked rice contain a very large amount of moisture, the oxygen absorber package becomes wet with water, causing a problem in that the original oxygen absorption capacity cannot be fully demonstrated. Therefore, there has been a demand for an oxygen absorber and oxygen absorber package that can be used with high-water activity foods containing a large amount of moisture and that can maintain its oxygen absorption capacity even in a wet environment. Therefore, an object of the present invention is to provide an oxygen absorber composition that can absorb oxygen for a long period of time even when applied to high-water activity foods.

[0007] That is, the gist of the present invention is as follows: [1] A composition containing iron powder (A), an alkali metal halide or alkaline earth metal halide (B), activated carbon (C), and an inorganic powder filler (D), wherein the inorganic powder filler (D) has an apparent density of 1.10 g / cm 3 excluding the iron powder (A), the alkali metal halide or alkaline earth metal halide (B), and the activated carbon (C). ３ 2.90g / cm or more ３ The oxygen absorber composition according to any one of the above [1] to [4], wherein the inorganic powder filler (D) is at least one selected from the group consisting of metal salts, elemental metals, and metal oxides. [2] The oxygen absorber composition according to the above [1] or [2], wherein the inorganic powder filler (D) is a metal carbonate. [4] The oxygen absorber composition according to any one of the above [1] to [3], wherein the inorganic powder filler (D) is calcium carbonate. [5] The oxygen absorber composition according to any one of the above [1] to [4], wherein the inorganic powder filler (D) is at least one selected from the group consisting of heavy calcium carbonate, ground seashells, calcite, marble, limestone, and precipitated calcium carbonate. [6] The oxygen absorbing composition according to any one of the above items [1] to [5], wherein the inorganic powder filler (D) has an average particle size of 10 to 500 μm. [7] The apparent density of the inorganic powder filler (D) is 1.10 g / cm ３ 1.50g / cm or more３ [8] The oxygen absorbing composition according to any one of [1] to [6] above, wherein the content of the inorganic powder filler (D) is 105 to 200 parts by mass per 100 parts by mass of the iron powder (A). [9] The oxygen absorbing composition according to any one of [1] to [8] above, wherein the alkali metal halide or alkaline earth metal halide (B) is an alkaline earth metal halide.

[10] The oxygen absorbing composition according to any one of [1] to [9] above, wherein the alkali metal halide or alkaline earth metal halide (B) is at least one selected from the group consisting of calcium chloride, magnesium chloride, magnesium bromide, and calcium bromide.

[11] The oxygen absorbing composition according to any one of [1] to

[10] above, wherein the content of the activated carbon (C) is 0.5 to 5.0 parts by mass per 100 parts by mass of the iron powder (A).

[12] The oxygen absorber composition according to any one of [1] to

[11] above, wherein the content of the alkali metal halide or alkaline earth metal halide (B) is 0.3 to 5.0 parts by mass per 100 parts by mass of the iron powder (A).

[13] The oxygen absorber composition according to any one of [1] to

[12] above, wherein the content of the alkali metal halide or alkaline earth metal halide (B) is 1.1 to 3.0 parts by mass per 100 parts by mass of the iron powder (A).

[14] An oxygen absorber package comprising the oxygen absorber composition according to any one of [1] to

[13] above and a breathable packaging material containing the oxygen absorber composition.

[15] A method for preserving a high water activity food, comprising sealing and preserving the oxygen absorber composition according to any one of [1] to

[13] above or the oxygen absorber package according to

[14] above and the high water activity food in a gas barrier container.

[16] A high water activity food package comprising the oxygen absorber composition according to any one of [1] to

[13] above or the oxygen absorber package according to

[14] above, and a high water activity food sealed in a gas barrier container.

[0008] According to the present invention, it is possible to provide an oxygen absorbing composition that can absorb oxygen for a long period of time even when applied to high water activity foods. Furthermore, according to the present invention, it is possible to provide an oxygen absorbing agent package, a method for preserving high water activity foods, and a high water activity food package.

[0009] Embodiments of the oxygen absorber composition, oxygen absorber package, high water activity food preservation method, and high water activity food package according to the present invention are described in detail below. In this specification, the term "A to B" used to describe numerical values ​​means "A or more and B or less" (when A<B) or "A or less and B or more" (when A>B). In addition, in the present invention, a combination of preferred embodiments is a more preferred embodiment.

[0010] [Oxygen Absorber Composition] The oxygen absorber composition of the present invention contains iron powder (A), an alkali metal halide or alkaline earth metal halide (B), activated carbon (C), and an inorganic powder filler (D), and the inorganic powder filler (D) has an apparent density of 1.10 g / cm 3 excluding the iron powder (A), the alkali metal halide or alkaline earth metal halide (B), and the activated carbon (C). ３ 2.90g / cm or more ３ The oxygen absorber composition of the present invention is an oxygen absorber composition having the above-described structure, and is capable of absorbing oxygen for a long period of time even when applied to foods with high water activity.

[0011] The reason why the oxygen absorber composition of the present invention exhibits the above-mentioned effects is unclear, but one possible reason is as follows. It is believed that the inorganic powder filler having an apparent density within a specific range is able to retain an appropriate amount of moisture without excessively retaining moisture evaporated from food. This prevents the oxidation reaction from being inhibited by excess moisture and provides moisture that can promote the oxidation reaction, making it possible to absorb oxygen even in the presence of high water activity foods. Furthermore, it is believed that the halide and activated carbon are able to supply moisture to the iron powder surface through deliquescence and adsorption / desorption, thereby promoting and sustaining the oxidation reaction. As described above, the oxygen absorber composition of the present invention, having the above-mentioned configuration, is able to absorb oxygen for a long period of time even when applied to high water activity foods.

[0012] Each component will be described below. <Iron Powder (A)> The oxygen absorbing composition of the present invention contains iron powder. The iron powder contained in the oxygen absorbing composition of the present invention is referred to as "iron powder (A)" (component A). The iron powder (A) in the oxygen absorbing composition of the present invention is a main agent for the oxygen scavenging reaction.

[0013] The iron powder (A) is not particularly limited, but is preferably one with an exposed surface of iron (zero-valent metallic iron). It may also have an extremely thin oxide film like a normal metal surface, as long as it does not impair the effects of the present invention. Specifically, reduced iron powder, electrolytic iron powder, atomized iron powder, etc., can be suitably used. Crushed or cut cast iron or the like can also be used. As the iron powder (A), one type of iron powder can be used alone, or two or more types of iron powder can be used in combination as needed. These iron powders are also readily available commercially and can be used.

[0014] The average particle size (D50) of the iron powder (A) is, for example, 3000 μm or less, preferably 1000 μm or less, more preferably 500 μm or less, and even more preferably 300 μm or less from the viewpoint of improving contact with oxygen. Furthermore, from the viewpoint of suppressing dust generation, it is preferably 1 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. Specifically, the average particle size (D50) of the iron powder (A) is, for example, 1 to 3000 μm, preferably 1 to 1000 μm, more preferably 10 to 500 μm, and even more preferably 20 to 300 μm. Iron powders having an average particle size within the above range can be obtained by appropriately selecting commercially available iron powders. Alternatively, iron powders can be obtained by, for example, classification using a sieve according to the desired average particle size. The average particle size of the iron powder (A) can be measured by the method described in the Examples.

[0015] The specific surface area of ​​the iron powder (A) is preferably 0.02 m from the viewpoint of oxygen absorption performance. ２ / g or more, more preferably 0.03 m ２ / g or more, and from the viewpoint of suppressing the generation of dust, it is preferably 0.40 m ２ / g or less, more preferably 0.15m ２ / g or less, more preferably 0.10m ２ / g or less, and even more preferably 0.07 m ２ / g or less, and even more preferably 0.045 m ２ Specifically, the specific surface area of ​​the iron powder (A) is preferably 0.02 to 0.40 m ２ / g, more preferably 0.03 to 0.15 m ２ / g, more preferably 0.03 to 0.10 m ２ / g, and even more preferably 0.03 to 0.07 m ２ / g, and even more preferably 0.03 to 0.045 m ２ The specific surface area of ​​the iron powder (A) can be measured by the method described in the Examples.

[0016] The content of the iron powder (A) in the oxygen absorbing composition is not particularly limited, but is preferably 15% by mass or more and 75% by mass or less, more preferably 20% by mass or more and 60% by mass or less, and even more preferably 25% by mass or more and 50% by mass or less.

[0017] <Alkali Metal Halide or Alkaline Earth Metal Halide (B)> The oxygen scavenger composition of the present invention contains an alkali metal halide or alkaline earth metal halide. The alkali metal halide or alkaline earth metal halide contained in the oxygen scavenger composition of the present invention is referred to as "alkali metal halide or alkaline earth metal halide (B)" (component B), also referred to as "halide (B)." The alkali metal halide or alkaline earth metal halide (B) in the oxygen scavenger composition of the present invention acts catalytically on the oxidation reaction of iron powder, improving the activity of the iron powder. Furthermore, the alkali metal halide or alkaline earth metal halide (B) prevents water contained in the oxygen scavenger composition from evaporating and being lost from the oxygen scavenger composition, thereby suppressing the transfer of moisture to the stored item. The halide (B) contained in the oxygen scavenger composition is preferably present on the surface of the iron powder, and more preferably contained in the oxygen scavenger composition as halide-coated iron powder. The presence of the halide (B) on the surface of the iron powder makes it easier for moisture to be attracted to the surface of the iron due to the deliquescence phenomenon of the halide (B), thereby improving the oxygen absorption performance.

[0018] The halide (B) is not particularly limited, but is a halide of an alkali metal or a halide of an alkaline earth metal, preferably a halide of an alkaline earth metal.

[0019] The alkali metal halide is preferably at least one selected from the group consisting of alkali metal chlorides, bromides, and iodides, more preferably at least one selected from the group consisting of alkali metal chlorides and bromides, and even more preferably chlorides. Among these, from the viewpoints of handleability, safety, etc., the alkali metal halide is preferably at least one selected from the group consisting of sodium chloride, potassium chloride, potassium bromide, and sodium bromide, more preferably at least one selected from the group consisting of sodium chloride and potassium chloride, and even more preferably sodium chloride.

[0020] The alkaline earth metal halide is preferably at least one selected from the group consisting of alkaline earth metal chlorides, bromides, and iodides, more preferably at least one selected from the group consisting of alkaline earth metal chlorides and bromides, and even more preferably chlorides. Among these, from the viewpoints of handling and safety, the alkaline earth metal halide is preferably at least one selected from the group consisting of calcium chloride, magnesium chloride, magnesium bromide, and calcium bromide, more preferably at least one selected from the group consisting of calcium chloride and magnesium chloride, and even more preferably calcium chloride. The halide (B) can be used alone, or two or more types can be used in combination as needed. In addition, the above-mentioned halide (B) is readily available as a commercially available product, and can also be used.

[0021] The content of the halide (B) is preferably 0.3 to 5.0 parts by mass, more preferably 0.4 to 4.0 parts by mass, even more preferably 0.5 to 3.0 parts by mass, still more preferably 1.0 to 3.0 parts by mass, even more preferably 1.1 to 3.0 parts by mass, still more preferably 1.1 to 2.5 parts by mass, and even more preferably 1.1 to 2.0 parts by mass, relative to 100 parts by mass of the iron powder (A). By setting the content of the halide (B) within the above range, moisture can be appropriately supplied to the iron powder, and the halide (B) exhibits its function as a reaction accelerator, allowing high oxygen absorption performance to be maintained for a long period of time even in the presence of foods with high water activity.

[0022] <Activated Carbon (C)> The oxygen absorbing composition of the present invention contains activated carbon. The activated carbon contained in the oxygen absorbing composition of the present invention is referred to as "activated carbon (C)" (component C). The activated carbon (C) in the oxygen absorbing composition of the present invention functions as a reaction accelerator and a water-retaining carrier.

[0023] The activated carbon (C) is not particularly limited, and raw materials may be wood, coconut shell, coal, or the like. However, from the viewpoint of using the oxygen absorber composition of the present invention for food, one or more types selected from wood and coconut shell are preferred. The properties of the activated carbon (C) are also not particularly limited, but from the viewpoint of ease of handling during production of the oxygen absorber composition, activated carbon in a granular or powder form with high fluidity is preferably used, and activated carbon with a shape close to spherical is more preferred. One type of activated carbon (C) can be used alone, or two or more types can be used in combination as needed. These activated carbons are readily available commercially and can also be used.

[0024] Furthermore, in terms of ease of handling during the production of the oxygen scavenger composition, the average particle size of the activated carbon (C) in powder form is preferably 0.1 μm or more and 1000 μm or less, more preferably 1 μm or more and 100 μm or less, and even more preferably 1 μm or more and 50 μm or less. As long as the activated carbon particles have a particle size within the above range, they can be used regardless of whether they are primary particles, agglomerated particles, or granulated particles. Activated carbons having a particle size within the above range can be used alone, or multiple types having different particle sizes can be mixed in any ratio. Such activated carbons are readily available commercially and can also be used.

[0025] The content of activated carbon (C) is preferably 0.5 to 5.0 parts by mass, more preferably 0.5 to 4.0 parts by mass, even more preferably 0.5 to 3.0 parts by mass, still more preferably 0.5 to 2.5 parts by mass, even more preferably 0.5 to 2.0 parts by mass, still more preferably 0.5 to 1.8 parts by mass, even more preferably 0.5 to 1.7 parts by mass, and even more preferably 0.5 to 1.5 parts by mass, relative to 100 parts by mass of iron powder (A). By setting the content of activated carbon (C) within the above range, moisture can be retained for a long period of time, thereby exhibiting its function as a reaction accelerator and maintaining high oxygen absorption performance for a long period of time even in the presence of high water activity foods.

[0026] The content of activated carbon (C) is preferably 0.2 to 3.0 parts by mass, more preferably 0.2 to 2.0 parts by mass, even more preferably 0.2 to 1.5 parts by mass, still more preferably 0.2 to 1.2 parts by mass, even more preferably 0.2 to 1.0 parts by mass, still more preferably 0.2 to 0.8 parts by mass, even more preferably 0.2 to 0.7 parts by mass, and even more preferably 0.2 to 0.6 parts by mass, relative to 100 parts by mass of the oxygen scavenger composition. By setting the content of activated carbon (C) within the above range, moisture can be retained for a long period of time, and therefore the activated carbon (C) can function as a reaction accelerator, and high oxygen absorption performance can be maintained for a long period of time even in the presence of high water activity foods.

[0027] <Inorganic powder filler (D)> The oxygen absorbing composition of the present invention has an apparent density of 1.10 g / cm３ 2.90g / cm or more ３ The oxygen absorber composition of the present invention contains the following inorganic powder filler. The inorganic powder filler contained in the oxygen absorber composition of the present invention is referred to as "inorganic powder filler (D)" (component D). The inorganic powder filler (D) is an inorganic powder other than the iron powder (A), the alkali metal halide or alkaline earth metal halide (B), and the activated carbon (C). In other words, the inorganic powder filler (D) is an inorganic powder that is not included in any of the iron powder (A), the alkali metal halide or alkaline earth metal halide (B), and the activated carbon (C). The inorganic powder filler (D) is an inorganic powder other than the iron powder (A), the alkali metal halide or alkaline earth metal halide (B), and the activated carbon (C). The content of the inorganic powder filler (D) in the oxygen absorber composition is 50 to 300 parts by mass per 100 parts by mass of the iron powder (A).

[0028] The apparent density of the inorganic powder filler (D) is 1.10 g / cm ３ 2.90g / cm or more ３ The apparent density of the inorganic powder filler (D) is preferably 1.10 g / cm or less. ３ 2.50g / cm or more ３ More preferably, 1.10 g / cm ３ 2.10g / cm or more ３ More preferably, it is 1.10 g / cm or less. ３ 1.90g / cm or more ３ and even more preferably 1.10 g / cm ３ 1.80g / cm or more ３ and even more preferably 1.10 g / cm ３ 1.50g / cm or more ３ and even more preferably 1.10 g / cm ３ 1.40g / cm or more ３ and even more preferably 1.20 g / cm ３ 1.40g / cm or more ３ and even more preferably 1.25 g / cm ３ 1.35g / cm or more ３When the apparent density of the inorganic powder filler (D) is within the above range, it is possible to suppress inhibition of oxidation reaction due to excess moisture, and even when the oxygen absorbing composition is applied to foods with high water activity, it is possible to absorb oxygen for a long period of time.

[0029] The content of the inorganic powder filler (D) in the oxygen absorber composition is 50 to 300 parts by mass per 100 parts by mass of the iron powder (A). The content of the inorganic powder filler (D) in the oxygen absorber composition is preferably 60 to 300 parts by mass, more preferably 80 to 300 parts by mass, even more preferably 100 to 300 parts by mass, still more preferably 100 to 250 parts by mass, still more preferably 105 to 200 parts by mass, still more preferably 120 to 180 parts by mass, and still more preferably 140 to 160 parts by mass per 100 parts by mass of the iron powder (A). By having the content of the inorganic powder filler (D) in the above range, inhibition of oxidation reactions due to excess moisture can be suppressed, and the oxygen absorber composition can absorb oxygen for a long period of time even when applied to foods with high water activity.

[0030] The content of the inorganic powder filler (D) in the oxygen absorber composition is preferably 10 to 100 parts by mass relative to 100 parts by mass of the oxygen absorber composition. The content of the inorganic powder filler (D) in the oxygen absorber composition is more preferably 20 to 100 parts by mass, even more preferably 30 to 100 parts by mass, still more preferably 35 to 100 parts by mass, even more preferably 35 to 80 parts by mass, still more preferably 40 to 70 parts by mass, even more preferably 45 to 70 parts by mass, and even more preferably 50 to 65 parts by mass, relative to 100 parts by mass of the oxygen absorber composition. By having the content of the inorganic powder filler (D) within the above range, inhibition of oxidation reactions due to excess moisture can be suppressed, and the oxygen absorber composition can absorb oxygen for a long period of time even when applied to foods with high water activity.

[0031] The inorganic powder filler (D) is not limited in type as long as it is a powdered inorganic material having the above-mentioned apparent density, but preferably contains at least one selected from the group consisting of metal salts, metal simple substances, and metal oxides. Metal salts, metal simple substances, and metal oxides are all preferred as the inorganic powder filler (D). However, metal oxides are more preferably metal salts or metal simple substances because they may attract moisture in the system due to the small amount of hydroxyl groups present on the surface of the metal oxide. Therefore, the inorganic powder filler (D) preferably contains at least one selected from the group consisting of metal salts, metal simple substances, and metal oxides, more preferably at least one selected from the group consisting of metal salts and metal simple substances, and even more preferably a metal salt. The inorganic powder filler (D) is more preferably at least one selected from the group consisting of metal salts, metal simple substances, and metal oxides. Metal salts, metal simple substances, and metal oxides are all preferred as the inorganic powder filler (D). However, metal oxides are more preferably metal salts or metal simple substances because they may attract moisture in the system due to the small amount of hydroxyl groups present on the surface of the metal oxide. Therefore, the inorganic powder filler (D) is more preferably at least one selected from the group consisting of a metal salt, a metal element, and a metal oxide, even more preferably at least one selected from the group consisting of a metal salt and a metal element, and even more preferably a metal salt. By using a metal salt, a metal element, or a metal oxide as the inorganic powder filler, inhibition of the oxidation reaction can be suppressed even in the presence of excess moisture, and even when the oxygen absorber composition is applied to a high water activity food, oxygen can be absorbed for a long period of time. This is thought to be because the filler does not easily absorb water, and inhibition of the oxidation reaction due to wetting of the oxygen absorber composition can be prevented even in the presence of excess moisture.

[0032] The metal salt is preferably at least one metal salt selected from the group consisting of metal carbonates, phosphates, nitrates, nitrites, borates, thiocyanates, and organic acid salts, more preferably metal carbonates. The metal in the metal salt is preferably at least one selected from the group consisting of alkaline earth metals, transition metals, alkali metals, and aluminum, more preferably alkaline earth metals, and even more preferably calcium. Therefore, the metal salt is more preferably at least one metal salt selected from the group consisting of alkaline earth metal carbonates, phosphates, nitrates, nitrites, borates, thiocyanates, and organic acid salts, more preferably alkaline earth metal carbonates, and even more preferably calcium carbonate. The use of calcium carbonate as an inorganic powder filler can suppress inhibition of oxidation reactions, allowing the oxygen absorber composition to absorb oxygen for a long period of time even when applied to high water activity foods. This is thought to be due to calcium carbonate's poor water absorption, which prevents inhibition of oxidation reactions due to wetting of the oxygen absorber composition even in the presence of excess moisture.

[0033] The metal element is preferably at least one selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements, Group 7 elements, Group 9 elements, Group 10 elements, Group 11 elements, Group 12 elements, and Group 13 elements, more preferably a Group 11 element, and even more preferably copper.

[0034] The metal in the metal oxide is preferably at least one selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements, Group 7 elements, Group 9 elements, Group 10 elements, Group 11 elements, Group 12 elements, and Group 13 elements, more preferably a Group 11 element, and even more preferably copper. Therefore, the metal oxide is more preferably an oxide of at least one metal selected from the group consisting of Group 4 elements, Group 5 elements, Group 6 elements, Group 7 elements, Group 9 elements, Group 10 elements, Group 11 elements, Group 12 elements, and Group 13 elements, even more preferably an oxide of a Group 11 element, and even more preferably copper oxide.

[0035] As such, a specific example of the inorganic powder filler (D) is preferably at least one selected from the group consisting of alkaline earth metal carbonates, simple Group 11 elements, and oxides of Group 11 elements, more preferably at least one selected from the group consisting of calcium carbonate, copper, and copper oxide, even more preferably at least one selected from the group consisting of calcium carbonate and copper, and still more preferably calcium carbonate.

[0036] As described above, the inorganic powder filler (D) is preferably a metal salt, more preferably a metal carbonate, even more preferably an alkaline earth metal carbonate, and even more preferably calcium carbonate. When the inorganic powder filler (D) is calcium carbonate, the inorganic powder filler (D) is preferably at least one selected from the group consisting of heavy calcium carbonate, crushed shells, calcite, marble, limestone, and precipitated calcium carbonate, more preferably at least one selected from the group consisting of marble and limestone. The use of marble or limestone as the inorganic powder filler can suppress inhibition of oxidation reactions, allowing the oxygen absorber composition to absorb oxygen for a long period of time even when applied to high water activity foods. This is thought to be due to the low water absorption properties of marble or limestone, which can prevent inhibition of oxidation reactions due to wetting of the oxygen absorber composition even in the presence of excess moisture. Examples of marble include Arabescato, Kansui-seki, Sivec White, Taiwan White, Bianco Carrara, and Perlino Caro, with Kansui-seki being preferred. An example of limestone is Hakuryu crushed stone, and Hakuryu crushed stone is preferred.

[0037] The average particle size of the inorganic powder filler (D) is preferably 10 to 500 μm, more preferably 20 to 500 μm, even more preferably 30 to 500 μm, even more preferably 40 to 500 μm, and even more preferably 50 to 450 μm. When the average particle size of the inorganic powder filler (D) is within the above range, inhibition of the oxidation reaction is suppressed, and the oxygen absorber composition can absorb oxygen for a long period of time even when applied to foods with high water activity. This is thought to be because fillers with an average particle size within the above range are less likely to retain water, and therefore, even in the presence of excess moisture, inhibition of the oxidation reaction due to wetting of the oxygen absorber composition can be prevented. The average particle size of the inorganic powder filler (D) is the average particle size (D50) at 50% cumulative frequency in the volume-based particle size distribution. More specifically, the average particle size of the inorganic powder filler (D) can be determined by the method described in the Examples.

[0038] <Other Components> In addition to the above components, the oxygen scavenger composition of the present invention may contain other components as needed, provided that the effects of the present invention are not impaired. Examples of other components include a flow improver, a catalyst, an odor absorbent, a heat dispersant, etc.

[0039] <Method for producing oxygen absorbing composition> The method for producing the oxygen absorbing composition of the present invention is not particularly limited, but preferably includes a step of mixing iron powder (A), an alkali metal halide or an alkaline earth metal halide (B), activated carbon (C), and an inorganic powder filler (D).

[0040] In order for iron to absorb oxygen, it is necessary to attract moisture to the surface of the iron, and this is achieved by utilizing the deliquescence phenomenon of metal salts. The halide (B) is preferably contained in the oxygen scavenger composition as an aqueous solution in which it is dissolved in water.

[0041] The mixing step may be (1) a step of mixing all components at once, (2) a step of preparing an aqueous solution of a halide (B) in water, adding the aqueous solution to a mixture of iron powder (A), activated carbon (C), and inorganic powder filler (D), mixing, and drying, or (3) a step of preparing an aqueous solution of a halide (B) in water, adding the aqueous solution to iron powder (A), mixing, and drying to obtain a halide-coated iron powder, and then mixing with activated carbon (C) and inorganic powder filler (D). Step (3) is more preferred because the deliquescence of the halide (B) makes it easier for moisture to be attracted to the surface of the iron, thereby improving oxygen absorption performance.

[0042] The mixing method is not particularly limited, and can be performed by shaking mixing, mixing with a mixer, etc. Specific examples of the mixer include a Nauta mixer (manufactured by Hosokawa Micron Corporation), a conical mixer (manufactured by Ohno Chemical Machinery Co., Ltd.), a vertical granulator (manufactured by Powrex Corporation), a high-speed mixer (manufactured by Earth Technica Corporation), and a granulator (manufactured by Akira Kiko Co., Ltd.).

[0043] Since iron, which is the main component of the oxygen scavenger, reacts with oxygen, the reaction proceeds gradually during the production of the oxygen scavenger composition. Therefore, mixing is preferably carried out in an inert atmosphere (in the case of a substantially closed system, the system is usually filled with an oxygen-free inert gas (e.g., nitrogen) atmosphere), and heat removal is preferably carried out as appropriate.

[0044] [Oxygen Absorber Package] The oxygen absorber package of the present invention comprises the oxygen absorber composition described above and a breathable packaging material containing the oxygen absorber composition.

[0045] (Breathable Packaging Material) The breathable packaging material is not particularly limited as long as it is a container that is breathable and allows oxygen to pass through. However, since the breathable packaging material contains the oxygen absorbing agent composition and is used together with the preserved item, particularly a food with a high water activity, a bag-like or small pouch-like form is preferred.

[0046] Examples of breathable packaging materials include those formed by laminating two breathable films together to form a bag, those formed by laminating one breathable film and one non-breathable film together to form a bag, and those formed by folding one breathable film and sealing the edges excluding the folded portion to form a bag. Furthermore, breathability may be imparted to a bag formed by laminating two non-breathable films together by sandwiching a breathable material, such as thread or a sheet with a breathable cross section, between the bonded portions. Compared to breathable packaging materials made of breathable films, breathable packaging materials obtained by sandwiching a breathable material between non-breathable films are preferred because they can suppress excessive moisture penetration.

[0047] The breathable film may be a single-layer film made of one type of breathable material or a laminated film made of two or more types of breathable materials. However, a laminated film is preferred because it is necessary to efficiently transmit oxygen, prevent leakage of the oxygen absorber composition, and moderately suppress moisture penetration. Among laminated films, a laminated film having an outer layer made of a thermoplastic resin, an intermediate layer made of paper, aluminum foil, or a thermoplastic resin, and an inner layer made of a heat-sealable thermoplastic resin is preferred. Here, the outer layer is located outside the oxygen absorber package and is a layer that comes into contact with the outside air and the stored item, the inner layer is located inside the oxygen absorber package and is a layer that comes into contact with the oxygen absorber composition, and the intermediate layer is a layer located between the outer layer and the inner layer.

[0048] The outer layer is preferably made of a thermoplastic resin, more preferably polyethylene terephthalate or biaxially oriented polypropylene. Furthermore, since the outer layer is laminated to the intermediate layer by heat sealing, it is preferably a two-layer film. Examples of thermoplastic resins used in layers other than polyethylene terephthalate or biaxially oriented polypropylene include low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer, ethylene-α-olefin copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, acid-modified polyolefin resin, polyvinyl acetate resin, poly(meth)acrylic resin, and polyvinyl chloride resin, with low-density polyethylene being preferred. The outer layer has a plurality of openings formed by perforation.

[0049] The intermediate layer is preferably made of paper, aluminum foil, or a thermoplastic resin, and more preferably made of paper or a thermoplastic resin. Examples of paper include water-repellent paper, kraft paper, fine paper (Western paper), and Japanese paper. The thermoplastic resin used in the intermediate layer is preferably a nonwoven fabric, such as a linear low-density polyethylene (LLDPE) nonwoven fabric, a polyethylene terephthalate nonwoven fabric, a composite nonwoven fabric (e.g., a polyethylene terephthalate-polyethylene sheath-core structure), or TYVEK (registered trademark, manufactured by DuPont-Asahi Flashspan Products Co., Ltd.). The aluminum foil has multiple openings formed by perforation. The inner layer is preferably made of a heat-sealable thermoplastic resin, and more preferably made of linear low-density polyethylene or unstretched polypropylene. The inner layer has multiple openings formed by perforation.

[0050] The air permeability of the breathable packaging material is preferably 1000 seconds / 100 cc or less, more preferably 100 seconds / 100 cc or less, and even more preferably 30 seconds / 100 cc or less, in terms of Gurley air permeability.

[0051] The thickness of the laminated film is preferably 30 μm to 300 μm, more preferably 40 μm to 250 μm, in which case the film can be used as a packaging material that maintains strength and has excellent heat-sealing properties and packaging suitability, compared to thicknesses outside the above range.

[0052] In the case of a breathable packaging material in which two non-breathable films are bonded together to form a bag, and a sheet having breathability in cross section is sandwiched between the bonded portions, the material may have a three-layer structure as described above, and a seal layer may be provided between each layer. Alternatively, the bag may be formed by bonding together the outer edge of a laminate consisting of a non-breathable film, a seal layer, a sheet having breathability in cross section, and another seal layer.

[0053] The material of the non-breathable film is preferably one selected from the group consisting of polyethylene terephthalate, polyamide, polypropylene, polycarbonate, and cellophane. The material of the sheet having breathability in cross section is preferably paper or nonwoven fabric. The paper is preferably at least one selected from the group consisting of Japanese paper, rayon-blended Japanese paper, and Western paper, and from the viewpoint of adhesiveness, rayon-blended Japanese paper is more preferable. Examples of nonwoven fabric include wet-laid nonwoven fabric, dry-laid nonwoven fabric, and spunbonded nonwoven fabric. Examples of nonwoven fabric materials include polyamide, polyethylene terephthalate, and rayon. Examples of materials for the sealing layer include polyethylene, polyethylene-vinyl acetate copolymer, ionomer, polybutadiene, and vinyl chloride.

[0054] [Method for Preserving High Water Activity Foods and High Water Activity Food Packages] The oxygen absorber composition and oxygen absorber package are capable of absorbing oxygen for a long period of time, even when the food being preserved has a high water activity, and are therefore suitable for preserving high water activity foods. Therefore, the method for preserving high water activity foods of the present invention is a method for preserving high water activity foods in which the oxygen absorber composition or the oxygen absorber package and the high water activity food are sealed in a gas barrier container for storage. The present invention also includes a method for preserving high water activity foods in which the oxygen absorber composition or the oxygen absorber package and the high water activity food are sealed in a gas barrier container for storage. The high water activity food package of the present invention is a high water activity food package in which the oxygen absorber composition or the oxygen absorber package and the high water activity food are sealed in a gas barrier container. The present invention also includes a high water activity food package in which the oxygen absorber composition or the oxygen absorber package and the high water activity food are sealed in a gas barrier container.

[0055] Although there are no limitations on the high water activity food used in the high water activity food preservation method and high water activity food package of the present invention, the effects of the present invention are clearly demonstrated by using a food with a water activity of 0.7 or higher. Therefore, the water activity of the high water activity food is preferably 0.7 or higher, more preferably 0.8 or higher, and even more preferably 0.9 or higher. By using the oxygen absorber composition and oxygen absorber package, oxygen can be absorbed for a long period of time even when used to preserve foods with a water activity of 0.7 or higher. The moisture content of the high water activity food is preferably 30% by mass or higher, more preferably 40% by mass or higher, and even more preferably 50% by mass or higher. The upper limit of the moisture content of the high water activity food is usually 70% by mass or lower. By using the oxygen absorber composition and oxygen absorber package, oxygen can be absorbed for a long period of time even when used to preserve foods with a moisture content of 30% by mass or higher.

[0056] Specific examples of the high water activity foods include cooked rice, rice cakes, rice flour dumplings, fresh noodles, fresh breadcrumbs, steamed buns, bread, etc., and preferably cooked rice and rice cakes. By using the oxygen absorber composition and the oxygen absorber package, oxygen can be absorbed for a long period of time even when stored together with foods with extremely high water activity such as cooked rice and rice cakes.

[0057] The gas barrier container used in the method for preserving high water activity foods and the high water activity food package of the present invention is not particularly limited as long as it is sealable and has substantial gas barrier properties, but from the viewpoint of blocking external ventilation, it is preferably made of an impermeable material. Specifically, it is preferable to use a gas barrier container having an oxygen permeability of 0.05 to 20 mL / (m), such as a multilayer sheet or film having a laminated structure such as polyethylene terephthalate / aluminum vapor deposition / polyethylene, oriented polypropylene / polyvinyl alcohol / polyethylene, or polyvinylidene chloride-coated oriented nylon / polyethylene, or a nylon-based coextruded multilayer sheet or film. ２ Bags and packaging containers made of a laminate of the gas barrier container (25°C, 50%RH) can be easily used. In addition to the above, metal cans, glass bottles, plastic containers, etc. can also be used as gas barrier containers.

[0058] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, but includes all aspects encompassed by the concept of the present invention and the scope of the claims, and can be modified in various ways within the scope of the present invention.

[0059] The present embodiment will be described in detail below using examples and comparative examples, but the present embodiment can be modified as appropriate as long as the effects of the present invention are achieved.

[0060] <Materials> The materials used in the examples and comparative examples are as follows: Iron powder: "JIP303-60A", manufactured by JFE Steel Corporation, average particle size 41 μm, specific surface area 0.037 m ２ / g Activated carbon: "A3", manufactured by Osaka Gas Chemicals Co., Ltd., powder form Calcium chloride: manufactured by Tokuyama Corporation

[0061] [Average particle size of iron powder] The average particle size of the iron powder was measured by using a standard sieve conforming to ISO 3310-1:2000 (equivalent to JIS Z8801-1:2006) and vibrating it for 5 minutes, and then measuring the average particle size (D50) at a cumulative frequency of 50% from the weight fraction of the sieve openings. [Specific surface area of ​​iron powder] The specific surface area (unit: m ２ / g) was measured based on the BET multipoint method in accordance with JIS Z8830:2013.

[0062] <Inorganic Powder Filler> Among the materials used in the Examples and Comparative Examples, the materials used as inorganic powder fillers are listed below: Kansui stone: "Kansui #50", manufactured by Nitto Funka Kogyo Co., Ltd., marble, calcium carbonate, average particle size 71.1 μm, apparent density 1.29 g / cm ３ Hakuryu crushed stone: "Hakuryu Ichirin", manufactured by Asahi Komatsu Co., Ltd., limestone, calcium carbonate, average particle size 312 μm, apparent density 1.27 g / cm ３ Copper: "Copper, powder", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average particle size 19.2 μm, apparent density 2.02 g / cm ３ Copper oxide: "copper (II) oxide", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average particle size 15.7 μm, apparent density 1.90 g / cm ３ Alumina: "Alumina A14", manufactured by Nippon Light Metal Holdings Co., Ltd., average particle size 55 μm, apparent density 0.76 g / cm ３ Silica sand: "Tohoku Silica Sand No. 8", manufactured by Tohoku Silica Sand Co., Ltd., average particle size 120 μm, apparent density 1.03 g / cm ３ Yellow iron oxide: "MTY-80", manufactured by Kanto Denka Finetech Co., Ltd., iron oxyhydroxide (FeOOH), average particle size 4.7 μm, apparent density 0.34 g / cm ３ Magnesium carbonate: "heavy magnesium carbonate", manufactured by Tomita Pharmaceutical Co., Ltd., average particle size 8.5 μm, apparent density 0.36 g / cm ３ Zinc: "Zinc, powder", manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., average particle size 4.6 μm, apparent density 3.09 g / cm ３

[0063] [Average Particle Diameter of Inorganic Powder Filler] The average particle diameter of the inorganic powder filler was measured as the average particle diameter (D50) at a cumulative frequency of 50% in a volumetric particle size distribution using a particle size distribution analyzer ("CAMSIZAR" manufactured by MICROTRAC). The measurement was performed twice under the following conditions, and the average value was taken as the average particle diameter of the inorganic powder filler. Refractive index: 1.45 Solvent: methyl ethyl ketone Shape: non-spherical [Apparent Density of Inorganic Powder Filler] In accordance with JIS K6720-2:1999, the inorganic powder filler was placed in a 100 mL container, and the mass was measured and calculated.

[0064] <Production of Oxygen Absorber Composition and Oxygen Absorber Package> Example 1 [1] Production of Oxygen Absorber Composition Calcium chloride, an alkaline earth metal halide, was dissolved in water to prepare a 10% calcium chloride aqueous solution. Next, 100 parts by mass of iron powder was mixed with the calcium chloride aqueous solution to give 1.25 parts by mass of calcium chloride equivalent, and the mixture was dried to prepare calcium chloride-coated iron powder. 101.25 parts by mass of this calcium chloride-coated iron powder was mixed with 1.5 parts by mass of activated carbon and 150 parts by mass of kansui stone as an inorganic powder filler to obtain an oxygen absorber composition.

[0065] [2] Production of Oxygen Absorber Package A polyethylene film was laminated on a polyethylene terephthalate film and perforated to obtain a breathable film (air resistance 0-500 seconds, measured by the Gurley method (JIS-P8117) using a Digital Oken Tester (manufactured by Asahi Seiko Co., Ltd.)). A double-sided packaging material was obtained by overlapping the polyethylene film side of the breathable film with the waterproof paper side of a breathable sheet made of waterproof paper laminated with perforated polyethylene as a sealing layer without bonding them together. The sealing layer side of the breathable sheet of this double-sided packaging material was then overlapped with the sealing layer of a separately prepared non-breathable film made of polyethylene terephthalate film laminated with a polyethylene film as a sealing layer, and three sides were heat-sealed to obtain a single-sided double-sided packaging bag with one side open. 3.5 g of the oxygen absorber composition was filled between the breathable sheet and the non-breathable film through the opening of the single-sided double-sided packaging bag, and the opening was sealed to obtain an oxygen absorber package (size: 45 mm x 50 mm).

[0066] Examples 2 to 4 and Comparative Examples 1 to 5 Oxygen absorber compositions and oxygen absorber packages were produced in the same manner as in Example 1, except that the inorganic powder filler, Kansuiseki, was changed to the fillers shown in Table 1.

[0067] <Excess oxygen absorption performance> Excess oxygen absorption performance was evaluated using the oxygen absorber compositions and oxygen absorber packages obtained in the examples and comparative examples. The oxygen absorber package (3.5 g of oxygen absorber composition) was placed in an oxygen barrier bag (size 220 mm x 300 mm, oxygen permeability 0.53 mL / (m ２ The oxygen absorber package was then placed in an oxygen barrier bag at a pressure of 1000 mL / 24h MPa or less (Mocon method, 20°C, 65% RH), and 1000 mL of air at 100% RH was then placed in the bag. The bag was then sealed and stored at 25°C. After confirming that the oxygen concentration in the oxygen barrier bag had fallen below 0.1%, the oxygen absorber package was removed. The oxygen absorber package was then struck with a hammer to pulverize the oxygen absorbing composition contained in the oxygen absorber package until no lumps remained. The oxygen absorber package was then opened, and the oxygen absorber composition was placed on filter paper. Water was added dropwise until the oxygen absorber composition on the filter paper was completely wet. After adding the water, the bag was left to stand for 60 minutes, and the oxygen absorber composition was then placed on a cotton cloth (80 μm thick) in a 100 cm ２ The powder was spread over an area of ​​100 mm, a cotton cloth was placed on top, and the powder was pressed for 10 minutes so that the powder and the cotton cloth were in complete contact, thereby removing the moisture. The moisture content of the oxygen absorber composition after the moisture removal was calculated using the following formula, and this was taken as the saturated moisture content. (Saturated moisture content (%)) = [(mass of oxygen absorber composition after moisture removal) - (mass of oxygen absorber composition before water addition)] / (mass of oxygen absorber composition after moisture removal) x 100

[0068] Using the obtained oxygen absorber composition after moisture removal, an oxygen absorber package was produced in the same manner as in Example 1. The oxygen absorber package was placed in an oxygen barrier bag, and 3000 mL of 100% RH air was added to the oxygen barrier bag, which was then sealed and stored at 25°C for 3 days. The amount of oxygen in the oxygen barrier bag after 3 days was measured. The amount of oxygen that was reduced was taken as the excess oxygen absorption performance. The greater the amount of oxygen that was reduced, the better the excess oxygen absorption performance, and the more oxygen can be absorbed even in the presence of a large amount of moisture, which is preferable.

[0069] The amount of oxygen in the oxygen barrier bag was measured using a gas analyzer (MOCON's "Check Mate 3") by inserting a hollow needle at the tip of a sampling silicone tube attached to the gas analyzer into the bag through a sampling rubber sheet (25 mm x 25 mm, 2 mm thick) that had been attached to the oxygen barrier bag in advance, and measuring the oxygen concentration inside the gas barrier bag.

[0070]

[0071] As shown in Table 1, the oxygen absorber compositions and oxygen absorber packages of the examples have excellent excess oxygen absorption performance and can absorb oxygen even in the presence of a large amount of moisture. On the other hand, the oxygen absorber compositions and oxygen absorber packages of the comparative examples, which contain inorganic powder fillers whose apparent density does not satisfy the specified range, have very low excess oxygen absorption performance, and it is clear that the oxidation reaction is inhibited by the large amount of moisture, resulting in poor oxygen absorption performance. From the above, it is clear that the oxygen absorber composition and oxygen absorber package of the present invention can absorb oxygen for a long period of time even when applied to foods with high water activity.

Claims

1. Contains iron powder (A), alkali metal halide or alkaline earth metal halide (B), activated carbon (C), and inorganic powder filler (D), and the inorganic powder filler (D) has an apparent density of 1.10 g / cm 3 excluding iron powder (A), alkali metal halide or alkaline earth metal halide (B), and activated carbon (C). ３ 2.90g / cm or more ３ The oxygen scavenger composition is as follows: wherein the content of the inorganic powder filler (D) is 50 to 300 parts by mass per 100 parts by mass of the iron powder (A).

2. The oxygen absorbing composition according to claim 1, wherein the inorganic powder filler (D) contains at least one selected from the group consisting of metal salts, elemental metals, and metal oxides.

3. The oxygen absorbing composition according to claim 1 or 2, wherein the inorganic powder filler (D) is a metal carbonate.

4. The oxygen absorbing composition according to any one of claims 1 to 3, wherein the inorganic powder filler (D) is calcium carbonate.

5. The oxygen absorbing composition according to any one of claims 1 to 4, wherein the inorganic powder filler (D) is at least one selected from the group consisting of heavy calcium carbonate, crushed seashells, calcite, marble, limestone, and precipitated calcium carbonate.

6. The oxygen absorbing composition according to any one of claims 1 to 5, wherein the inorganic powder filler (D) has an average particle size of 10 to 500 μm.

7. The apparent density of the inorganic powder filler (D) is 1.10 g / cm ３ 1.50g / cm or more ３ The oxygen scavenger composition according to any one of claims 1 to 6, wherein:

8. The oxygen absorbing composition according to any one of claims 1 to 7, wherein the content of the inorganic powder filler (D) is 105 to 200 parts by mass per 100 parts by mass of the iron powder (A).

9. The oxygen scavenger composition according to any one of claims 1 to 8, wherein the alkali metal halide or alkaline earth metal halide (B) is an alkaline earth metal halide.

10. The oxygen scavenger composition according to any one of claims 1 to 9, wherein the alkali metal halide or alkaline earth metal halide (B) is at least one selected from the group consisting of calcium chloride, magnesium chloride, magnesium bromide, and calcium bromide.

11. The oxygen absorbing composition according to any one of claims 1 to 10, wherein the content of activated carbon (C) is 0.5 to 5.0 parts by mass per 100 parts by mass of iron powder (A).

12. The oxygen scavenger composition according to any one of claims 1 to 11, wherein the content of the alkali metal halide or alkaline earth metal halide (B) is 0.3 to 5.0 parts by mass per 100 parts by mass of the iron powder (A).

13. The oxygen scavenger composition according to any one of claims 1 to 12, wherein the content of the alkali metal halide or alkaline earth metal halide (B) is 1.1 to 3.0 parts by mass per 100 parts by mass of the iron powder (A).

14. An oxygen absorber package comprising the oxygen absorber composition according to any one of claims 1 to 13 and a breathable packaging material containing the oxygen absorber composition.

15. A method for preserving a high water activity food, comprising enclosing the oxygen absorber composition according to any one of claims 1 to 13 or the oxygen absorber package according to claim 14 and the high water activity food in a gas barrier container for storage.

16. A high water activity food package comprising the oxygen absorber composition according to any one of claims 1 to 13 or the oxygen absorber package according to claim 14, and a high water activity food enclosed in a gas barrier container.

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