Acid inhibitor, acid inhibition enhancing agent, acid inhibition method, and method for enhancing acid inhibition effect

Abstract

To provide an oxidation inhibitor, an oxidation inhibition action enhancer, an oxidation inhibiting method, and an enhancement method of oxidation inhibitory action capable of realizing excellent oxidation inhibition action, difficult to generate a problem of odor, and advantageous also in the cost.SOLUTION: An oxidation inhibitor method containing a polyalkyleneimine compound as an active ingredient, an oxidation inhibitor enhancing agent containing the polyalkyleneimine compound as an active ingredient, and the polyalkyleneimine compound and the oxidation inhibition target substance in an oxidation inhibition target object coexist, and a method of enhancing the oxidation inhibition action of the oxidation inhibiting substance containing by making coexisting the polyalkyleneimine compound and the oxidation inhibiting substance.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an antioxidant, an antioxidant activity enhancer, an antioxidant method, and a method for enhancing antioxidant activity.

Background Art

[0002] Oxidation of lipids such as edible oils has long been a problem in the fields of processing and preservation. This is because the unsaturated fatty acid components that make up lipids undergo a radical chain oxidation reaction via lipid peroxyl radicals, resulting in the production of peroxides and, secondarily, carbonyl compounds such as aldehydes, which emit unpleasant odors and exhibit toxicity. With the recent increasing health consciousness, edible oils called functional oils have attracted strong interest. In particular, rice oil rich in omega-6 fatty acid components and rich in phenolic antioxidant components, and linseed oil and perilla oil rich in omega-3 fatty acid components, etc., have high attention from the perspective of preventing lifestyle-related diseases. These edible oils contain a large amount of unsaturated fatty acid components as constituent fatty acids, and therefore, oxidative deterioration occurs rapidly and it is difficult to stably store them over a long period. In addition, the health risks of chemical substances generated by this oxidative deterioration have also been pointed out, and effective antioxidant measures for lipids (unsaturated lipids) having unsaturated fatty acid components are required.

[0003] It is known that the radical chain oxidation reaction of unsaturated lipids proceeds as follows. First, a highly reactive lipid peroxyl radical (LOO·) is generated by an initiation reaction in which unsaturated lipid (LH) reacts with oxygen (O2). This reaction can be expressed as follows. LH + O2 → L· + HO2 L· + O2 → LOO· The generated LOO· reacts with unsaturated lipid to produce hydroperoxide lipid (LOOH). LOO· + LH → L· + LOOH In this way, the oxidation of lipids proceeds in a chain reaction, resulting in a rapid generation of hydroperoxide lipids.

[0004] Conventionally, the addition of a compound having a phenolic hydroxyl group (phenolic compound) has been effective for suppressing the above-described chain oxidation reaction. The phenolic compound captures lipid peroxyl radicals and suppresses the oxidation of fats and oils by becoming a stable radical itself. This reaction will be shown below using vitamin E (V E H), which is frequently used as an antioxidant for lipids, as an example. V E H + LOO· → VE· + LOOH

[0005] In order to suppress the oxidation of fish oil, which is a highly unsaturated lipid, it has been proposed to use spermine, which is a natural polyamine compound (Non-Patent Document 1). Non-Patent Document 1 shows that spermine is effective in suppressing the oxidation of fish oil, and that this antioxidant effect does not directly act on the lipid by itself, but acts synergistically with tocopherol (vitamin E) originally contained in fish oil to promote the antioxidant effect of fish oil.

Prior Art Documents

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Polyamine compounds such as spermine have a peculiar odor, and when blended into edible oils and the like, there are restrictions on their usage amounts and the like. In addition, polyamine compounds are relatively expensive, and there are also restrictions on their general use from the perspective of cost.

[0008] An object of the present invention is to provide an antioxidant, an antioxidant effect enhancer, an antioxidant method, and a method for enhancing an antioxidant effect that achieve an excellent antioxidant effect, hardly cause odor problems, and are also advantageous in terms of cost.

[0009] The above problems of the present invention are solved by the following means. 〔1〕 An antioxidant containing a polyalkyleneimine compound as an active ingredient. 〔2〕 The antioxidant according to 〔1〕, which contains an antioxidant substance. 〔3〕 The antioxidant according to 〔1〕, which is used in the coexistence with an antioxidant substance. 〔4〕 The antioxidant according to 〔2〕 or 〔3〕, wherein the antioxidant substance contains a phenolic compound. 〔5〕 The antioxidant according to any one of 〔1〕 to 〔4〕, which suppresses the oxidation of unsaturated lipids. 〔6〕 An antioxidant action enhancer containing a polyalkyleneimine compound as an active ingredient. 〔7〕 The antioxidant action enhancer according to 〔6〕, which is used in the coexistence with an antioxidant substance. 〔8〕 An antioxidant method including coexisting a polyalkyleneimine compound and an antioxidant substance in an object to be antioxidized. 〔9〕 A method for enhancing the antioxidant action of an antioxidant substance, including coexisting a polyalkyleneimine compound and an antioxidant substance. 〔10〕 A method for storing an object to be antioxidized, including storing the object to be antioxidized in the presence of a polyalkyleneimine compound. 〔11〕 The method for storing an object to be antioxidized according to 〔10〕, including storing in the coexistence of an antioxidant substance. 〔12〕 An antioxidant material obtained by immobilizing a polyalkyleneimine compound on a substrate. 〔13〕 The antioxidant material according to claim 12, which is used in the coexistence with an antioxidant substance. 〔14〕 An antioxidant action enhancer material obtained by immobilizing a polyalkyleneimine compound on a substrate. 〔15〕 An antioxidant action enhancer described in

[14] , which is used in the coexistence with an oxidation inhibitor.

[16] A storage container for an object to be antioxidized, in which a polyalkyleneimine compound is immobilized on at least a part of the inner wall. [Advantages of the Invention]

[0010] The antioxidant, antioxidant action enhancer, antioxidant method, and method for enhancing antioxidant action of the present invention achieve excellent antioxidant action, hardly cause odor problems, and are also advantageous in terms of cost. [Brief Description of the Drawings]

[0011]

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Figure 9

Best Mode for Carrying Out the Invention

[0012] Preferred embodiments of the present invention will be described below. However, the present invention is not to be construed as being limited to the embodiments, mechanisms of action, etc. described below, except as defined in the present invention.

[0013] [Antioxidant] The antioxidant of the present invention contains a polyalkyleneimine compound as an active ingredient. The object to be antioxidized to which the antioxidant of the present invention is applied is not particularly limited. For example, those that are liable to undergo oxidative degradation by radicals are suitable as objects to be antioxidized. The main mechanism of action of the polyalkyleneimine compound, which is the active ingredient of the antioxidant of the present invention, is considered to enhance the antioxidant action of the antioxidant substance in the coexistence of a substance (antioxidant substance) that directly acts on the object to be antioxidized and exhibits an antioxidant effect. However, the mechanism of action of the antioxidant of the present invention is not limited to the above as long as the polyalkyleneimine compound is involved in the antioxidation of the object to be antioxidized. Preferred embodiments of the antioxidant of the present invention will be described in detail.

[0014] [Polyalkyleneimine Compound]< Polyalkyleneimine is a polymer or oligomer whose main chain is composed of an alkylene group and an imino group. Polyalkyleneimine may be linear or preferably has a branched structure. Polyalkyleneimine can be obtained by ring-opening polymerization of alkyleneimine. In the present invention, the term "polyalkyleneimine compound" includes polyalkyleneimine itself and also forms in which a part of the hydrogen atoms is substituted, as long as the effects of the present invention are not impaired.

[0015] The number of carbon atoms in the alkylene group of the polyalkyleneimine compound is preferably an integer of 1 to 10, more preferably an integer of 1 to 6, still more preferably an integer of 2 to 4, and still more preferably 2 or 3. The polyalkyleneimine compound preferably includes a polyethyleneimine compound, and more preferably is a polyethyleneimine compound.

[0016] The molecular weight of the polyalkyleneimine compound is not particularly limited, and can be widely used from relatively low molecular weight ones to high molecular weight ones. As will be described later, the difference in molecular weight does not substantially affect the expression of the effects of the present invention. The molecular weight of the polyalkyleneimine compound can be, for example, 300 to 500,000 as the average molecular weight, preferably 400 to 100,000, preferably 400 to 50,000, and preferably 500 to 30,000. The average molecular weight may be 600 or more, 1000 or more, 2000 or more, or 3000 or more. In the present invention or the specification, the average molecular weight is the number average molecular weight, and for commercially available products, it means the molecular weight described in the catalog.

[0017] The polyalkyleneimine compound can be synthesized by a conventional method or obtained from the market. Examples of commercially available polyalkyleneimine compounds include Epomin (registered trademark, manufactured by Nippon Shokubai Co., Ltd.), Lupasol (registered trademark, manufactured by BASF), polyethyleneimine (manufactured by Fujifilm Wako Pure Chemical Corporation), PEI MAX (manufactured by Polysciences), etc. Polyalkyleneimine can be obtained at a reagent price about 1 / 100 of that of low molecular amine compounds such as spermine, which are known to have an antioxidant effect.

[0018] <Object to be antioxidized> As the object to be inhibited from oxidation targeted by the oxidation inhibitor of the present invention, those liable to undergo oxidative degradation by radicals are preferred. For example, those containing one or more of unsaturated lipids (lipids having unsaturated fatty acids as constituent components (which may be unsaturated fatty acids themselves)), hydrocarbons, alcohols, aldehydes, ketones, etc. are included. The object to be inhibited from oxidation is preferably liquid at normal temperature (25°C). The object to be inhibited from oxidation preferably has chemical physical properties such that oxidation readily proceeds when it comes into contact with air. In the present invention, "lipid" is used to mean including fats and oils (glycerides), complex lipids (phospholipids, glycolipids, etc.), derived lipids (fatty acids, etc.). Further, unsaturated lipid means a lipid in which the fatty acid component constituting the lipid has an unsaturated bond (typically a carbon-carbon double bond). Examples of fatty acids (unsaturated fatty acids) having an unsaturated bond (typically a carbon-carbon double bond) that can constitute unsaturated lipids include ω (omega)-3 fatty acids, ω-6 fatty acids, ω-7 fatty acids, ω-9 fatty acids, ω-10 fatty acids, etc. Specific examples of the unsaturated fatty acids include α-linolenic acid, eicosatetraenoic acid, eicosapentaenoic acid, docosapentaenoic acid, docosahexaenoic acid, linoleic acid, γ-linolenic acid, arachidonic acid, docosatetraenoic acid, docosapentaenoic acid, palmitoleic acid, vaccenic acid, paulic acid, oleic acid, elaidic acid, erucic acid, nervonic acid, sapienic acid, etc.

[0019] As described above, it is known that unsaturated lipids cause a radical chain oxidation reaction when they come into contact with air, and those containing unsaturated lipids are preferred as the object to be inhibited from oxidation. When the object to be inhibited from oxidation contains unsaturated lipids, the proportion of unsaturated fatty acids in all constituent fatty acids constituting the unsaturated lipids is preferably 20% by mass or more, more preferably 30% by mass or more, preferably 40% by mass or more, preferably 50% by mass or more, preferably 60% by mass or more, preferably 70% by mass or more, preferably 80% by mass or more. This proportion may be 100% by mass, usually 99% by mass or less, and preferably 95% by mass or less. When the object to be inhibited from oxidation contains unsaturated lipids, it is preferable that these unsaturated lipids have, as constituent fatty acids, one or more of the above-mentioned α-linolenic acid, eicosatetraenoic acid, eicosapentaenoic acid, docosapentaenoic acid, docosahexaenoic acid, linoleic acid, γ-linolenic acid, arachidonic acid, docosatetraenoic acid, docosapentaenoic acid, palmitoleic acid, vaccenic acid, paulic acid, oleic acid, elaidic acid, erucic acid, nervonic acid, and sapienic acid. It is more preferable that they have one or more of oleic acid, linoleic acid, α-linolenic acid, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid, and it is preferable that they have one or more of α-linolenic acid, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid. It is also preferable that the object to be inhibited from oxidation containing unsaturated lipids is edible oil. Examples of such edible oils include perilla oil, linseed oil, safflower oil, grape seed oil, soybean oil, sunflower oil, corn oil, cottonseed oil, sesame oil, rapeseed oil, rice bran oil, olive oil, palm oil, fish oil, canola oil, perilla oil, chia seed oil, Sacha Inchi oil, rose hip oil, etc. It may also be a mixed oil of one or more of these. Further, lipids whose constituent fatty acid composition has been artificially modified by transesterification or the like, and lipids artificially produced by an esterification reaction of an alcohol such as glycerin and a fatty acid are also preferable as the object to be inhibited from oxidation. In addition, phospholipids having unsaturated fatty acids as constituent fatty acids are also preferable as the object to be inhibited from oxidation.

[0020] The object to be inhibited from oxidation preferably contains an antioxidant. For example, vitamin E, which is known as an antioxidant, is contained in many edible oils. By coexisting the antioxidant of the present invention with such an edible oil, as will be described later, vitamin E, which has been oxidized to a radical by itself, extracts hydrogen from the polyalkyleneimine compound and is regenerated as an antioxidant. As a result, the antioxidant action of vitamin E can be continuously exhibited.

[0021] <Antioxidant> As described above, the antioxidant of the present invention can enhance the antioxidant action on the object to be antioxidized in the coexistence of an antioxidant substance. The antioxidant substance usually suppresses the oxidation of the object to be antioxidized by preventing the oxidation of the object to be antioxidized by being oxidized itself, or by reducing the oxidized object to be antioxidized by being oxidized itself. As the antioxidant substance, a compound having a radical scavenging ability is preferable. Examples of such compounds include phenolic compounds, carotenoids, ascorbic acid compounds (including salt forms), thiol compounds, etc., and one or more of these can be used. Among them, the antioxidant substance preferably contains a phenolic compound. The phenolic compound is not particularly limited as long as it is a compound having a phenolic hydroxyl group. For example, vitamin E (tocopherol or tocotrienol), oryzanol, hydroquinone, butylhydroxyanisole, dibutylhydroxytoluene, butylhydroquinone, resveratrol, quercetin, ferulic acid, catechin, etc. can be mentioned, and one or more of these can be used as the phenolic compound.

[0022] Taking the case where the object to be antioxidized contains unsaturated lipid and the object to be antioxidized contains vitamin E which is an antioxidant substance (or when vitamin E is added separately) as an example, FIG. 1 shows the continuous antioxidant mechanism of unsaturated lipid by allowing the antioxidant of the present invention to act on the object to be antioxidized. In FIG. 1, an example using polyethyleneimine (PEI, denoted as AH in FIG. 1) as an active ingredient of the antioxidant of the present invention is shown. Note that FIG. 1 includes estimations, and the present invention is not limited to the mechanism shown in FIG. 1 except as defined in the present invention. As shown in FIG. 1, in the chain oxidation reaction of unsaturated lipid, vitamin E (V E H) acts on lipid peroxyl radical (LO2·) and is oxidized itself to form a stable radical (V E·) suppresses the oxidation of unsaturated lipids (formation of lipid peroxides). However, if all of the vitamin E is oxidized, it can no longer exhibit the oxidation-suppressing effect, and a rapid generation of lipid peroxides will occur. Polyethyleneimine acts on the radical of vitamin E (V E ·), and a hydrogen atom is extracted from the -NH- group of polyethyleneimine to form a radical (A·) itself, thereby reducing vitamin E (V E · to V E H), and it is considered to restore the function as an oxidation-suppressing substance. The above is an example. Even when the oxidation-suppression target contains something other than vitamin E as an oxidation-suppressing substance (for example, the phenolic compound other than vitamin E described above), the polyalkyleneimine compound can exhibit an oxidation-suppressing effect by the same mechanism of action.

[0023] In one usage form of the oxidation inhibitor of the present invention, the oxidation inhibitor of the present invention is added to the oxidation-suppression target, or the oxidation inhibitor of the present invention is immobilized on the inner wall of the container containing the oxidation-suppression target and brought into contact with the oxidation-suppression target, or a material obtained by immobilizing the oxidation inhibitor of the present invention on a substrate is put into the oxidation-suppression target, etc., and by coexisting the oxidation-suppression target and the polyalkyleneimine compound, the oxidation-suppressing substance originally contained in the oxidation-suppression target and the polyalkyleneimine compound contained in the oxidation inhibitor of the present invention act on the oxidation-suppression target in a concerted manner to exhibit an oxidation-suppressing effect on the oxidation-suppression target. In another usage form of the antioxidant of the present invention, the antioxidant of the present invention can be added to the object to be antioxidized, or the antioxidant of the present invention can be immobilized on the inner wall of the container containing the object to be antioxidized and brought into contact with the object to be antioxidized, or a material obtained by immobilizing the antioxidant of the present invention on a substrate can be put into the object to be antioxidized, so that the object to be antioxidized coexists with the polyalkyleneimine compound contained in the antioxidant of the present invention. Separately from the antioxidant of the present invention, an antioxidant substance can be added to the object to be antioxidized, and the polyalkyleneimine compound and the antioxidant substance can act on the object to be antioxidized in a concerted manner to exhibit an antioxidant effect on the object to be antioxidized. In each usage form of the antioxidant of the present invention, the quantitative ratio of the polyalkyleneimine compound to the antioxidant substance can be, for example, polyalkyleneimine compound / antioxidant substance (mass ratio) of 1 / 10 to 1000 / 1, preferably 1 / 5 to 500 / 1, preferably 1 / 3 to 100 / 1, and preferably 1 / 1 to 25 / 1. In each usage form of the antioxidant of the present invention, the quantitative ratio of the object to be antioxidized to the polyalkyleneimine compound can be, for example, object to be antioxidized / polyalkyleneimine compound (mass ratio) of 10 / 1 to 10000 / 1, preferably 50 / 1 to 5000 / 1, preferably 100 / 1 to 3000 / 1, and preferably 300 / 1 to 1000 / 1.

[0024] In one form of the antioxidant of the present invention, the antioxidant of the present invention is added to a polyalkyleneimine compound, and the antioxidant itself of the present invention contains an antioxidant substance. In this form of the antioxidant, by adding the antioxidant of the present invention to the object to be antioxidized, even if the object to be antioxidized does not contain an antioxidant substance, a state in which a polyalkyleneimine compound and an antioxidant substance coexist in the object to be antioxidized can be created. In this case, the respective contents of the polyalkyleneimine compound and the antioxidant substance in the antioxidant of the present invention may be appropriately set according to the purpose. For example, the polyalkyleneimine compound / antioxidant substance (mass ratio) can be set to 1 / 10 to 1000 / 1, preferably 1 / 5 to 500 / 1, preferably 1 / 3 to 100 / 1, and preferably 1 / 1 to 25 / 1.

[0025] The antioxidant of the present invention may be in a form consisting of a polyalkyleneimine compound or may be in a form consisting of a polyalkyleneimine compound and an antioxidant substance as described above. Further, in addition to the polyalkyleneimine compound and the antioxidant substance, a medium, various additives, etc. may be appropriately included according to the purpose. In the antioxidant of the present invention, the content of the polyalkyleneimine compound can be appropriately set according to the form of the agent. For example, 1% by mass or more is preferable, 5% by mass or more may be used, 10% by mass or more may be used, 30% by mass or more is also preferable, 50% by mass or more is also preferable, and 70% by mass or more is also preferable. The antioxidant of the present invention may be in a form consisting of a polyalkyleneimine compound. In the remainder of the antioxidant of the present invention excluding the polyalkyleneimine compound, according to the purpose, it may be in a form appropriately containing the above-described antioxidant substance, a medium such as a solvent, various additives, etc.

[0026] The polyalkyleneimine compound is a highly viscous polymer and is difficult to dissolve in unsaturated lipids and the like. Therefore, the polyalkyleneimine compound can be immobilized on a substrate and brought into contact with the object to be inhibited from oxidation in this immobilized state. This immobilization can be carried out by coating the antioxidant of the present invention on the substrate or chemically immobilizing the components of the antioxidant of the present invention on the substrate.

[0027] The antioxidant of the present invention may be in the form of a composition in which each component is uniformly mixed, or may be in a form in which each component is non-uniformly present. Further, the polyalkyleneimine compound and other components (for example, antioxidant substances) may be separately packaged, etc., and each component may be in a more separated form (so-called antioxidant set). In this set form, each separated component constituting the agent can be used in a form of being mixed at the time of use, added to or brought into contact with the object to be inhibited from oxidation simultaneously or with a time difference.

[0028] [Antioxidant action enhancer] The antioxidant action enhancer of the present invention contains a polyalkyleneimine compound as an active ingredient, acts on an antioxidant substance, and is an agent for enhancing the antioxidant action of the antioxidant substance. In the description of the antioxidant action enhancer of the present invention, the polyalkyleneimine compound, the object to be inhibited from oxidation, and the antioxidant substance are respectively synonymous with the polyalkyleneimine compound, the object to be inhibited from oxidation, and the antioxidant substance described in the section of the antioxidant of the present invention. The antioxidant action enhancer of the present invention is different from the antioxidant of the present invention in that it does not contain an antioxidant substance, and the other points (shape of the agent, usage form) are appropriately applied to the matters described for the antioxidant of the present invention. That is, the antioxidant action enhancer of the present invention can be applied to an object to be inhibited from oxidation that already contains an antioxidant substance or an object to be inhibited from oxidation for which an antioxidant substance is planned to be blended. Further, the antioxidant action enhancer of the present invention can also act on the object to be inhibited from oxidation after being mixed with the antioxidant substance. The antioxidant action enhancer of the present invention is added to the object to be antioxidized, or the antioxidant action enhancer of the present invention is immobilized on the inner wall of the container to bring it into contact with the object to be antioxidized, or the material obtained by immobilizing the antioxidant action enhancer of the present invention on the substrate is put into the object to be antioxidized, so that the polyalkyleneimine compound and the antioxidant substance act on the object to be antioxidized in a concerted manner, and the antioxidant action of the antioxidant substance on the object to be antioxidized can be effectively enhanced. In each use form of the antioxidant action enhancer of the present invention, the quantitative ratio of the polyalkyleneimine compound to the antioxidant substance can be, for example, polyalkyleneimine compound / antioxidant substance (mass ratio) of 1 / 10 to 1000 / 1, preferably 1 / 5 to 500 / 1, preferably 1 / 3 to 100 / 1, and preferably 1 / 1 to 25 / 1. Also, in each use form of the antioxidant action enhancer of the present invention, the quantitative ratio of the object to be antioxidized to the polyalkyleneimine compound can be, for example, object to be antioxidized / polyalkyleneimine compound (mass ratio) of 10 / 1 to 10000 / 1, preferably 50 / 1 to 5000 / 1, preferably 100 / 1 to 3000 / 1, and preferably 300 / 1 to 1000 / 1. In the antioxidant action enhancer of the present invention, the content of the polyalkyleneimine compound can be appropriately set according to the form of the agent. For example, 1% by mass or more is preferable, 5% by mass or more may be used, 10% by mass or more may be used, 30% by mass or more is also preferable, 50% by mass or more is also preferable, 70% by mass or more is also preferable, 80% by mass or more is also suitable, and 90% by mass or more is also preferable. The antioxidant action enhancer of the present invention may be in a form consisting of a polyalkyleneimine compound. In the antioxidant action enhancer of the present invention, the remainder excluding the polyalkyleneimine compound can be in a form appropriately containing a medium such as a solvent and various additives according to the purpose.

[0029] [Antioxidant method] The oxidation inhibition method of the present invention includes coexisting a polyalkyleneimine compound and an oxidation inhibitor in an object to be inhibited from oxidation. That is, by coexisting a polyalkyleneimine compound and an oxidation inhibitor in an object to be inhibited from oxidation, the polyalkyleneimine compound and the oxidation inhibitor act on the object to be inhibited from oxidation in a concerted manner to exhibit an oxidation inhibition effect on the object to be inhibited from oxidation. In the description of the oxidation inhibition method of the present invention, the polyalkyleneimine compound, the object to be inhibited from oxidation, and the oxidation inhibitor are respectively synonymous with the polyalkyleneimine compound, the object to be inhibited from oxidation, and the oxidation inhibitor described in the section on the oxidation inhibitor of the present invention. The embodiments of the oxidation inhibition method of the present invention are not limited in any way other than as defined by the present invention. In one embodiment of the oxidation inhibition method of the present invention, the oxidation inhibitor of the present invention can be used as a source of the polyalkyleneimine compound or the oxidation inhibitor. Further, in another embodiment, the oxidation inhibition effect enhancer of the present invention can also be used as a source of the polyalkyleneimine compound. In the oxidation inhibition method of the present invention, the quantitative ratio of the polyalkyleneimine compound to be used and the oxidation inhibitor can be, for example, polyalkyleneimine compound / oxidation inhibitor (mass ratio) of 1 / 10 to 1000 / 1, preferably 1 / 5 to 500 / 1, preferably 1 / 3 to 100 / 1, and preferably 1 / 1 to 25 / 1. Also, in the oxidation inhibition method of the present invention, the quantitative ratio of the object to be inhibited from oxidation to the polyalkyleneimine compound can be, for example, object to be inhibited from oxidation / polyalkyleneimine compound (mass ratio) of 10 / 1 to 10000 / 1, preferably 50 / 1 to 5000 / 1, preferably 100 / 1 to 3000 / 1, and preferably 300 / 1 to 1000 / 1.

[0030] [Method for enhancing oxidation inhibition effect] The method for enhancing the oxidation inhibitory effect of the present invention (the method for enhancing the oxidation inhibitory effect of the present invention) includes coexisting a polyalkyleneimine compound and an oxidation inhibitor. For example, by coexisting a polyalkyleneimine compound and an oxidation inhibitor in the object to be inhibited from oxidation, the polyalkyleneimine compound and the oxidation inhibitor act on the object to be inhibited from oxidation in a concerted manner, and the oxidation inhibitory effect of the oxidation inhibitor on the object to be inhibited from oxidation can be enhanced. In the description of the method for enhancing the oxidation inhibitory effect of the present invention, the polyalkyleneimine compound, the object to be inhibited from oxidation, and the oxidation inhibitor are synonymous with the polyalkyleneimine compound, the object to be inhibited from oxidation, and the oxidation inhibitor described in the section on the oxidation inhibitor of the present invention, respectively. In one embodiment of the method for enhancing the oxidation inhibitory effect of the present invention, the oxidation inhibitor of the present invention can be used as a source of the polyalkyleneimine compound or the oxidation inhibitor. Further, in another embodiment, the oxidation inhibitory effect enhancer of the present invention can also be used as a source of the polyalkyleneimine compound. In the method for enhancing the oxidation inhibitory effect of the present invention, the amount ratio of the polyalkyleneimine compound to be used and the oxidation inhibitor can be such that the polyalkyleneimine compound / oxidation inhibitor (mass ratio) is 1 / 10 to 1000 / 1, preferably 1 / 5 to 500 / 1, more preferably 1 / 3 to 100 / 1, and still more preferably 1 / 1 to 25 / 1. Also, in the method for enhancing the oxidation inhibitory effect of the present invention, the amount ratio of the object to be inhibited from oxidation to the polyalkyleneimine compound can be such that the object to be inhibited from oxidation / polyalkyleneimine compound (mass ratio) is 10 / 1 to 10000 / 1, preferably 50 / 1 to 5000 / 1, more preferably 100 / 1 to 3000 / 1, and still more preferably 300 / 1 to 1000 / 1.

[0031] The oxidation suppression method, oxidation suppression effect enhancer, oxidation suppression method, and oxidation enhancement method of the present invention can be applied not only when storing an object to be oxidation-suppressed in a container or the like, but also when a living body (including humans, non-human mammals (livestock, pets, etc.), and other vertebrates) ingests functional oil or the like, and can be used to effectively express the physiological activity of the functional oil in the living body. For example, by ingesting euglena oil or the like that contains a large amount of α-linolenic acid as a constituent fatty acid, which has attracted attention as a functional oil, and ingesting the oxidation inhibitor or oxidation suppression effect enhancer of the present invention, oxidation of unsaturated lipids contained in euglena oil in the digestive tract or the like can be suppressed, and its physiological activity can be effectively expressed. In addition, the oxidation inhibitor or oxidation suppression effect enhancer of the present invention can also be expected to have an effect of suppressing the oxidation of unsaturated lipids (for example, phospholipids that are cell membrane components) present in the living body by ingesting these substances.

[0032] Regarding the above-described embodiments, according to the present invention, the following inventions are further provided. (1) A method for storing an object to be oxidation-suppressed, comprising storing the object to be oxidation-suppressed in the presence of a polyalkyleneimine compound. (2) The method for storing an object to be oxidation-suppressed according to (1), comprising storing in the coexistence of an oxidation-suppressing substance. (3) The method for storing an object to be oxidation-suppressed according to (1) or (2), wherein the object to be oxidation-suppressed contains unsaturated lipids. (4) The method for storing an object to be oxidation-suppressed according to any one of (1) to (3), wherein the object to be oxidation-suppressed is edible oil. (5) An oxidation inhibitor comprising a polyalkyleneimine compound immobilized on a substrate. (6) The oxidation inhibitor according to (5), used in the coexistence of an oxidation-suppressing substance. (7) An oxidation suppression effect enhancer comprising a polyalkyleneimine compound immobilized on a substrate. (8) The oxidation suppression effect enhancer according to (7), used in the coexistence of an oxidation-suppressing substance. (9) A storage container for an object to be oxidation-suppressed, wherein a polyalkyleneimine compound is immobilized on at least a part of the inner wall. The storage container for the oxidation-inhibiting target according to (9), wherein the oxidation-inhibiting target contains unsaturated lipids. The storage container for the oxidation-inhibiting target according to (9) or (10), wherein the oxidation-inhibiting target is edible oil.

Examples

[0033] The present invention will be described in more detail based on the examples. However, the present invention is not construed as being limited to the forms of the examples other than those defined in the present invention.

[0034] [Oxidation inhibition test of unsaturated lipids - 1] <Materials> As a model of unsaturated lipids, methyl linoleate (concentration 95% by mass, manufactured by Tokyo Chemical Industry Co., Ltd.) was used. Since the methyl group does not affect the oxidation of the fatty acid group, methyl linoleate is considered appropriate as a model of unsaturated lipids. α-Tocopherol (Wako 1st Grade, manufactured by Fujifilm Wako Pure Chemical Corporation), which is vitamin E, was used as the oxidation inhibitor. As polyalkyleneimine compounds, polyethyleneimines with different molecular weights (manufactured by Fujifilm Wako Pure Chemical Corporation) were prepared. One is polyethyleneimine with an average molecular weight of 10,000 and an amino group composition of 35 mol% of primary (-NH2), 35 mol% of secondary (-NH-), and 30 mol% of tertiary (-N(-)-). The other is polyethyleneimine with an average molecular weight of 600 and an amine composition of 35% primary, 35% secondary, and 30% tertiary.

[0035] <Test method> The Rancimat test was conducted. Figure 2 is a schematic diagram of the Rancimat apparatus (743 Rancimat, Metrohm AG, Switzerland). This Rancimat apparatus 10 consists of a reaction section including an air supply nozzle 1, a reaction tube 2 with polyethyleneimine (PEI) coated on the bottom, and a block heater 3 for controlling its temperature, and a measurement section equipped with a conductivity cell 5. In the reaction section, the sample 4 (3.0 g of methyl linoleate, 7.0 μmol of α-tocopherol) placed in the reaction tube 2 was maintained at 120 °C, and air was blown into the sample 4 at a flow rate of 20 L / h to forcibly promote the oxidation of the sample 4. In the measurement section, the volatile oxidation products 6 generated by oxidation were collected with pure water 7, and the degree of progress of oxidation was evaluated by measuring its conductivity. Three types of polyethyleneimine coating amounts on the bottom of the reaction tube 2, namely 0.003 g (3 mg), 0.0065 g (6.5 nm), and 0.01 g (10 mg), were prepared and compared. In addition, in order to ensure that the coating form did not affect the results, polyethyleneimine was applied to the bottom of the reaction tube 2 in a multi-point pattern of 10 points or more (only 3 points out of 10 or more are shown in Figure 2 for schematic illustration purposes).

[0036] <Effect of the molecular weight of polyethyleneimine> Using polyethyleneimines with average molecular weights of 10,000 and 600 respectively, the polyethyleneimine coating amount on the bottom of the reaction tube 2 was set to 0.0065 g and applied in a multi-point pattern, and the Rancimat test was conducted under the above conditions. The results are shown in Figure 3. As shown in Figure 3, almost no difference was observed in the change of conductivity over time. From this result, it was judged that the influence of the molecular weight of polyethyleneimine on oxidation inhibition was substantially negligible. Therefore, subsequent tests were conducted using polyethyleneimine with an average molecular weight of 10,000.

[0037] <Effect of the coating amount of polyethyleneimine> The effect of the coating amount of polyethyleneimine was verified by conducting the Rancimat test under the above conditions. For reference, the Rancimat test was also conducted when the sample did not contain α-tocopherol. The results are shown in Figure 4. As shown in Figure 4, when the sample is α-tocopherol (VE No antioxidant effect was observed without containing (H). That is, no direct antioxidant effect on the sample was observed for polyethyleneimine (PEI). Also, even when the sample contained α-tocopherol, without co-existing polyethyleneimine, the time when the conductivity began to increase vertically was only slightly delayed, and its antioxidant effect was quite limited. In contrast, in the sample, when α-tocopherol and polyethyleneimine co-existed, it was found that the time when the conductivity began to increase vertically could be greatly delayed. Also, this delay effect (antioxidant action) was enhanced in proportion to the coating amount of polyethyleneimine. From the above results, it was found that polyethyleneimine has the effect of dramatically enhancing the antioxidant effect in the coexistence with antioxidant substances such as α-tocopherol. When polyethyleneimine is added, a rapid increase in conductivity is observed in the initial stage (until about 2 minutes after the start of the experiment). That this initial increase in conductivity is not due to the oxidation promotion by polyethyleneimine was confirmed by directly titrating the amount of peroxide. Polyethyleneimine is used as a CO2 absorbent and is known to have the property of releasing the absorbed CO2 at high temperatures. The increase in conductivity at the initial stage of measurement is considered to be caused by, for example, the released CO2 dissolving in the ultrapure water in the measurement part and becoming carbonate ions.

[0038] Regarding the results shown in Fig. 4, a quantitative evaluation of the antioxidant effect of polyethyleneimine was performed. As an index for comparing the antioxidant effects, the length of the induction period (IP), which is the period suppressing oxidation, was determined. Here, the method for obtaining the length of IP will be explained with reference to Fig. 5. The graph in Fig. 5 shows the results in Fig. 4 when the coating amount of polyethyleneimine was 0.01 g (although it was shown by a broken line for convenience in Fig. 4, it is shown by a solid line in Fig. 5). Tangents were drawn to the section (I) where the progress of oxidation was slow and the conductivity progressed gently, and the section (II) where oxidation progressed rapidly and the conductivity increased vertically to reach 25 μS / cm, respectively, and the time of the intersection was defined as the induction period (IP).

[0039] Figure 6 shows a plot of the relationship between the IP of polyethyleneimine and the number of secondary amino groups (-NH-). The number of secondary amino groups (-NH-) was adjusted by the addition amount of polyethyleneimine. For comparison, the results for the low-molecular polyamine compounds spermine (Spe) and spermidine (Spd) are also shown in the figure. From the results in Figure 6, it was found that polyethyleneimine, spermine, and spermidine all showed a linear relationship between the number of secondary amino groups and the IP. In particular, it should be noted that the increase rate (slope) of the IP per secondary amino group in polyethyleneimine is overwhelmingly higher than that in spermine and spermidine. It is speculated that some factor due to the polymer structure of polyethyleneimine raises the antioxidant effect of α-tocopherol to an extremely high level. Thus, when using polyethyleneimine with a low reagent price, it is possible to exhibit the excellent antioxidant effect of interest while further suppressing its usage amount.

[0040] The above action of polyethyleneimine is considered to lie in continuously and highly efficiently expressing the antioxidant effect of α-tocopherol by regenerating radicalized α-tocopherol with high efficiency. This was verified by capturing the change over time in the α-tocopherol concentration in the sample.

[0041] <Quantification of α-tocopherol in the sample> Quantification of the α-tocopherol concentration in the sample was performed using a high-performance liquid chromatography system (manufactured by Waters) equipped with a fluorescence detector on a sample diluted with hexane and filtered through a 0.2-μm filter (manufactured by Sartorius Stedim Biotech). As the column, a normal-phase BEH HILIC (manufactured by Waters, particle size 1.6 μm, φ2.1 mm × 100 mm) was used. As the eluent, a mixed solution of hexane:ethyl acetate:acetic acid with a volume ratio of 99.5:0.5:0.18 was used. The supply flow rate was 0.7 cm 3The flow rate was 1.0 mL / min and the column temperature was 323 K. A fluorescence detector was used for the analysis, and the excitation wavelength was set at 298 nm and the fluorescence wavelength was set at 325 nm.

[0042] Figure 7 shows the measurement results (■) of α-tocopherol concentration when 0.003 g of polyethyleneimine was used. For reference, the change in conductivity over time under the same conditions is also shown. In addition, the measurement results (▲) of α-tocopherol concentration and the change in conductivity over time when no polyethyleneimine was added are also shown together. When no polyethyleneimine was added, it can be seen that the α-tocopherol concentration decreased rapidly with time, and after α-tocopherol was consumed, oxidation proceeded rapidly. On the other hand, when polyethyleneimine was added, the α-tocopherol concentration remained constant during the prolonged IP period. This indicates that polyethyleneimine is oxidized itself, and thereby reduces and regenerates the oxidized α-tocopherol, continuously expressing the oxidation inhibitory effect of α-tocopherol and achieving a long-term oxidation inhibitory effect.

[0043] [Antioxidant test for unsaturated lipids - 2] The antioxidant effect of polyethyleneimine on actual edible oil was investigated. Figure 8 shows the change in conductivity over time when polyethyleneimine was added to grape seed oil. There was no substantial difference in IP between the case of grape seed oil alone and the case where α-tocopherol was added and no polyethyleneimine was added. When both polyethyleneimine and α-tocopherol were added, the IP was extended by about 3 times. From this, it was found that polyethyleneimine shows an antioxidant effect on edible oil added with α-tocopherol. Also, the measurement results in grape seed oil showed that the IP was shorter under the same addition conditions than when methyl linoleate in the model system was used. The reason for this is not clear, but it is possible that coexisting substances in grape seed oil have a negative impact on the prolongation of IP.

[0044] Figure 9 also shows the change over time in conductivity when polyethyleneimine is added to perilla oil. In perilla oil as well, similar to grape seed oil, there was no substantial difference in IP between the case of perilla oil alone and the case where α-tocopherol was added but polyethyleneimine was not added, and oxidation proceeded rapidly. On the other hand, when both polyethyleneimine and α-tocopherol were added, the IP was significantly extended. From the above results, it was found that polyethyleneimine exhibits an oxidation inhibitory effect on edible oils to which α-tocopherol has been added. Among the edible oils alone, perilla oil, which is rich in linolenic acid that is easily oxidized, was oxidized more rapidly than grape seed oil. However, when polyethyleneimine and α-tocopherol were added, oxidation of perilla oil was suppressed for a longer time. Perilla oil often contains natural antioxidants as well. It is conceivable that due to the synergistic action of polyethyleneimine and its antioxidant, perilla oil showed a higher oxidation inhibitory effect than grape seed oil. Actually, Figure 9 shows that even when polyethyleneimine is added to perilla oil without adding α-tocopherol, a sufficiently long oxidation inhibitory effect is exhibited. This result suggests that even without adding α-tocopherol, the antioxidants inherently present in perilla oil work in concert with polyethyleneimine to effectively suppress the oxidation of perilla oil.

Explanation of Symbols

[0045] 10 Rancimat apparatus 1 Air supply nozzle 2 Reaction tube 3 Block heater 4 Sample 5 Conductivity cell 6 Volatile oxidation product 7 Pure water

Claims

1. An antioxidant comprising, as an active ingredient, a combination of a polyalkyleneimine compound and an antioxidant substance, and functioning as an enhancer for the antioxidant action of the antioxidant substance by the polyalkyleneimine compound.

2. The antioxidant according to Claim 1, wherein the antioxidant substance contains a phenolic compound.

3. The antioxidant according to Claim 1 or 2 for suppressing the oxidation of unsaturated lipids.

4. An antioxidant action enhancer comprising a polyalkyleneimine compound as an active ingredient.

5. The antioxidant action enhancer according to Claim 4, used in the coexistence of an antioxidant substance.

6. A method for enhancing the antioxidant action of an antioxidant substance, comprising coexisting a polyalkyleneimine compound and an antioxidant substance.

7. A method for storing an object to be antioxidized, comprising storing the object to be antioxidized in the presence of a polyalkyleneimine compound and an antioxidant substance which is a compound different from the polyalkyleneimine compound.

8. An antioxidant action enhancer formed by immobilizing a polyalkyleneimine compound on a substrate.

9. The antioxidant action enhancer according to Claim 8, used in the coexistence of an antioxidant substance.

10. A storage container for enhancing the antioxidant action of an object to be antioxidized, formed by immobilizing a polyalkyleneimine compound on at least a part of the inner wall.

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