Oil-soluble antioxidant composition

Abstract

To provide an oil-soluble antioxidant composition having high antioxidant activity. [Solution] An oil-in-oil droplet type oil-soluble antioxidant composition in which an aqueous phase containing gallic acid, tea catechins, glycerin, and water is emulsified in an oil phase containing a lipophilic emulsifier, glycerin, and oil components, and which does not contain an oil-soluble antioxidant.

Description

Technical Field

[0001] The present invention relates to an oil-soluble antioxidant composition.

Background Art

[0002] Oils and fats (such as salad oil and sesame oil) and oil and fat products cause various quality deteriorations due to the auto-oxidation of oils and fats during their manufacturing process or storage. Especially recently, due to the influence of global warming, the temperature in summer has risen significantly, and the opportunity to be exposed to high temperatures has increased, so the oxidation of oils and fats is promoted by heat more than ever. As a result, there has been a problem that the quality of oils and fats and oil and fat products deteriorates and the use (taste) period becomes extremely short.

[0003] Specific examples of quality deterioration due to the oxidation of oils and fats include the generation of an unpleasant odor (deterioration odor), discoloration, and a decrease in flavor. In addition, oxidized oil changes to lipid peroxide, but it is said that if a large amount of lipid peroxide oxidized in food is ingested, a part of it is absorbed into the body, causing abnormalities in biological functions such as heartburn and diarrhea.

[0004] Therefore, preventing the oxidation of oils and fats is important for maintaining the quality of oils and fats and oil and fat products. Also, since the price of oils and fats has skyrocketed in the market, it is important from the viewpoints of reducing the raw material costs of food manufacturers and restaurants, and reducing the environmental load by reducing the amount of waste oil.

[0005] Various proposals have been made regarding technologies for preventing the oxidation of oils and fats. For example, Patent Document 1 discloses a green tea extract treated with tannase, protease, and cell wall degrading enzyme during and / or after extraction of green tea leaves, which contains catechins (a general term for eight types: catechin, gallocatechin, catechin gallate, gallocatechin gallate, epicatechin, epigallocatechin, epicatechin gallate, epigallocatechin gallate) and gallic acid, and has an antioxidant composition characterized by containing, as an active ingredient, a green tea extract in which the ratio of the combined amount of epigallocatechin and gallic acid to the combined amount of catechins and gallic acid is 0.6 to 0.9.

[0006] Furthermore, Patent Document 2 proposes an antioxidant oil composition containing 2.5 to 65% by weight of a water-soluble antioxidant in the aqueous phase, and 1 to 38% by weight of the aqueous phase, which is further dispersed in the oil phase with a particle size of 300 nm or less, with carbohydrates added so that the total water-soluble solid content in the aqueous phase is 18 to 79% by weight, and containing 0.5 to 18% by weight of water, and containing only an oil-soluble emulsifier with an HLB of 7 or less as an emulsifier. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 4443359 [Patent Document 2] Patent No. 7343001 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, conventional antioxidants for oils and fats do not adequately meet current market demands, and therefore, there is a need for the development of oil-soluble antioxidant compositions with high antioxidant activity.

[0009] In view of these circumstances, the object of the present invention is to provide an oil-soluble antioxidant composition having high antioxidant activity. [Means for solving the problem]

[0010] The present inventors conducted diligent research to solve the above problems and, as a result, discovered that an oil-in-water droplet type emulsifying formulation containing gallic acid and tea catechins as antioxidants has high antioxidant power, leading to the present invention.

[0011] Thus, the present invention provides the following: [1] An oil-soluble antioxidant composition of the water-in-oil type, characterized in that an aqueous phase containing gallic acid, tea catechins, glycerin, and water is emulsified in an oil phase containing a lipophilic emulsifier, glycerin, and oil components, and does not contain an oil-soluble antioxidant. [2] The oil-soluble antioxidant composition according to [1], comprising gallic acid and tea catechins in a mass ratio of 1:0.1 to 3.0. [3] The oil-soluble antioxidant composition according to [1] or [2], wherein the aqueous phase further comprises sodium lactate and citric acid. [4] An oil-soluble antioxidant composition according to any one of [1] to [3], comprising sodium lactate and citric acid in a mass ratio of 1:0.2 to 2.0. [5] An oil-soluble antioxidant composition according to any one of [1] to [4], wherein the appearance is transparent. [6] An oil-soluble antioxidant composition according to any one of [1] to [5] above, for suppressing the deterioration odor of oils and fats caused by thermal deterioration. [7] The following steps: 1) A step of preparing an oil phase mixture containing an oily component, a lipophilic emulsifier, and glycerin. 2) A step of preparing an aqueous phase mixture containing gallic acid, tea catechins, glycerin, and water. 3) Adding the aqueous phase mixture from 2) to the oil phase mixture from 1) to emulsify it into a water droplet type in oil, A method for producing an oil-soluble antioxidant composition, characterized by containing [a certain substance]. [8] The following steps: 1) A step of preparing an oil phase mixture containing an oily component, a lipophilic emulsifier, glycerin, gallic acid, and tea catechins. 2) A step of preparing an aqueous phase mixture containing water and glycerin, 3) Adding the aqueous phase mixture from 2) to the oil phase mixture from 1) to emulsify it into a water droplet type in oil, A method for producing an oil-soluble antioxidant composition, characterized by containing [a certain substance]. [9] A method for producing an oil-soluble antioxidant composition according to [7] or [8], further comprising the step of adjusting the ratio of the refractive index of the aqueous phase mixture to the refractive index of the oil phase mixture to be 0.5 to 1.5. [Effect of the Invention]

[0012] According to the present invention, there is provided an oil-soluble antioxidant composition having a high antioxidant power and capable of suppressing the generation of the deterioration odor of fats and oils. [Brief Description of the Drawings]

[0013] [Figure 1] It is a diagram showing the results of the primary screening. [Figure 2] It is a photograph showing the appearance of the oil-soluble antioxidant composition of an embodiment of the present invention. [Figure 3] It is a photograph showing the appearance of the oil-soluble antioxidant composition of an embodiment of the present invention. [Figure 4] It is a photograph showing the appearance of the oil-soluble antioxidant composition of an embodiment of the present invention. [Figure 5] It is a photograph showing the appearance of the oil-soluble antioxidant composition of an embodiment of the present invention. [Figure 6] It is a photograph showing the appearance of the oil-soluble antioxidant composition of an embodiment of the present invention. [Modes for Carrying Out the Invention]

[0014] As described above, the present invention is an oil-in-water type oil-soluble antioxidant composition in which an aqueous phase portion containing gallic acid, tea catechins, glycerin and water is emulsified in an oil phase portion containing a lipophilic emulsifier, glycerin and an oil component. Hereinafter, the oil-soluble antioxidant composition of the present invention (hereinafter simply referred to as "antioxidant composition") will be described in detail.

[0015] (A) Aqueous phase portion As described above, the aqueous phase portion of the antioxidant composition of the present invention is composed of gallic acid, tea catechins, glycerin and water. Gallic acid is known as a water-soluble antioxidant with high antioxidant power and is also designated as a food additive antioxidant. In this invention, gallic acid and tea catechins, which have historically had difficulty exhibiting their inherent superior antioxidant power against fats and oils due to their low solubility in oils and oils despite their high antioxidant power, are made into water-in-oil emulsions. By imparting lipophilicity to these compounds, it becomes possible to exert the high antioxidant power of gallic acid and tea catechins against fats and oils. Therefore, in this invention, oil-soluble antioxidants, which are often used in combination with gallic acid in the past, become unnecessary, which is advantageous in terms of manufacturing and cost.

[0016] The gallic acid content is typically 0.1 to 20% by mass, preferably 1 to 15% by mass, and more preferably 3 to 10% by mass, based on the total mass of the antioxidant composition. A gallic acid content within this range is preferable for obtaining a practically effective and strong antioxidant capacity.

[0017] In the antioxidant composition of the present invention, the coexistence of tea catechins with gallic acid has significant importance not only in imparting the antioxidant power of tea catechins but also in preventing the precipitation of gallic acid from the antioxidant composition. Tea catechins are a collective term for eight types: catechin, gallocatechin, catechin gallate, gallocatechin gallate, epicatechin, epigallocatechin, epicatechin gallate, and epigallocatechin gallate, and are usually present in amounts of 10 to 25% by mass per dry weight of freshly picked tea leaves. All tea catechins have strong antioxidant power, but epigallocatechin gallate has the strongest antioxidant power on its own, and epigallocatechin also belongs to the category of relatively strong antioxidants, and the difference in their antioxidant power is not very large. Tea catechins can be used alone or in appropriate combinations of two or more types. Particularly preferred are those containing epigallocatechin gallate as the main component. An example of a commercially available product is Polyphenon 70S (trade name, manufactured by Mitsui Norin Co., Ltd.).

[0018] The tea catechin content is typically 0.1 to 25% by mass, preferably 1 to 15% by mass, and more preferably 3 to 10% by mass, based on the total mass of the antioxidant composition. Having a tea catechin content within this range is preferable for obtaining a practical and strong antioxidant effect.

[0019] The mass ratio of gallic acid to tea catechins is typically 1:0.1 to 3.0, preferably 1:0.2 to 2.0, and more preferably 1:0.3 to 1.2, particularly from the viewpoint of suppressing the deterioration odor of oils and fats caused by thermal degradation. By setting the mass ratio of gallic acid to tea catechins as described above, high antioxidant power can be obtained, and the generation of deterioration odor can be effectively suppressed.

[0020] Glycerin contributes to the stability of the emulsion and the stable dissolution of gallic acid. The glycerin content in the aqueous phase is usually 1 to 40% by mass, preferably 5 to 25% by mass, and more preferably 10 to 20% by mass, based on the total mass of the antioxidant composition. If the glycerin content is less than 5% by mass, practically sufficient antioxidant power cannot be obtained, while if it is more than 17% by mass, the viscosity of the antioxidant composition increases, making it difficult to handle and reducing its handling properties. From the viewpoint of stably dissolving gallic acid, the mass ratio of gallic acid to glycerin is usually 1:0.1 to 10, preferably 1:1.0 to 6.0, and more preferably 1:2.0 to 5.5.

[0021] While reducing the glycerin content in the aqueous phase of the antioxidant composition has the advantage of lowering the viscosity and improving handling properties, it also has the disadvantage of reducing antioxidant capacity. To address this disadvantage, the aqueous phase of the antioxidant composition of the present invention preferably contains sodium lactate and citric acid in addition to gallic acid, tea catechins, glycerin, and water. That is, the antioxidant composition of the present invention preferably is an oil-in-oil droplet type oil-soluble antioxidant composition in which the aqueous phase containing gallic acid, tea catechins, glycerin, water, sodium lactate, and citric acid is emulsified in an oil phase containing a lipophilic emulsifier, glycerin, and oil components. Further incorporating sodium lactate and citric acid into the aqueous phase of the antioxidant of the present invention can prevent a decrease in antioxidant capacity. In other words, incorporating sodium lactate and citric acid makes it possible to achieve both improved handling properties and prevention of a decrease in antioxidant capacity.

[0022] Sodium lactate, like glycerin, plays a role in contributing to the stability of the emulsion and the stable dissolution of gallic acid. The sodium lactate content is usually 0.5 to 10% by mass, preferably 1 to 7% by mass, and more preferably 2 to 5% by mass, based on the total mass of the antioxidant composition. A sodium lactate content within the above range is preferable for achieving the stability of the emulsion and the stable dissolution of gallic acid. The mass ratio of gallic acid to sodium lactate is usually 1:0.1 to 5.0, preferably 1:0.2 to 2.0, and more preferably 1:0.5 to 1.5, from the viewpoint of stably dissolving gallic acid.

[0023] When sodium lactate is used alone, it converts gallic acid to gallate salt, leading to a decrease in antioxidant capacity. However, by combining it with citric acid, the decrease in antioxidant capacity of gallic acid associated with the use of sodium lactate can be prevented. The citric acid content is usually 0.1 to 20% by mass, preferably 0.2 to 12% by mass, and more preferably 1 to 6% by mass, based on the total mass of the antioxidant composition. It is preferable for the sodium lactate content to be within the above range in order to prevent the decrease in antioxidant capacity of gallic acid associated with the use of sodium lactate. The mass ratio of sodium lactate to citric acid (sodium lactate:citric acid) is usually 1:0.2 to 2.0, preferably 1:0.4 to 1.5, and more preferably 1:0.6 to 1.2, particularly from the viewpoint of preventing a decrease in antioxidant capacity.

[0024] The mass ratio of gallic acid, sodium lactate, and citric acid (gallic acid:sodium lactate:citric acid) is typically 0.2-10.0:1:0.2-2.0, preferably 0.5-5.0:1:0.4-1.5, and more preferably 0.6-2.0:1:0.6-1.2, in order to balance the stable dissolution of gallic acid with preventing a decrease in antioxidant capacity.

[0025] Water plays a crucial role not only in forming emulsified particles containing dissolved gallic acid and tea catechins, but also in adjusting the refractive index (making the antioxidant composition transparent). The water content is typically 0.5 to 20% by mass, preferably 2 to 15% by mass, and more preferably 5 to 12% by mass, relative to the total mass of the antioxidant composition. A water content within this range is preferable for achieving transparency and appropriate handling properties of the antioxidant composition.

[0026] (B) Oil phase As described above, the oil phase of the antioxidant composition of the present invention is composed of a lipophilic emulsifier, glycerin, and an oil component. Lipophilic emulsifiers play a particularly important role in dissolving gallic acid, and if their amount is insufficient, gallic acid is more likely to precipitate. Examples of lipophilic emulsifiers include various glycerin fatty acid esters, propylene glycol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, and polyglycerin fatty acid esters. Polyglycerin fatty acid esters are particularly preferred. A commercially available example is SY Glister CRS-75 (polyglyceryl-6 polyricinoleate, trade name, manufactured by Sakamoto Kogyo Co., Ltd.).

[0027] The content of the lipophilic emulsifier is typically 0.1 to 50% by mass, preferably 1 to 35% by mass, and more preferably 10 to 30% by mass, based on the total mass of the antioxidant composition. A lipophilic emulsifier content within this range is preferable for stably dispersing the emulsion particles in the continuous oil phase.

[0028] Glycerin contributes to the stability of the emulsion and the stable dissolution of gallic acid. The glycerin content in the oil phase is usually 0.5 to 50% by mass, preferably 1 to 30% by mass, and more preferably 10 to 20% by mass, based on the total mass of the antioxidant composition. A glycerin content within the above range is preferable for the stable dispersion of emulsion particles in the continuous oil phase. The ratio of glycerin content in the aqueous phase to glycerin content in the oil phase is usually 90:10 to 0:100, preferably 70:30 to 10:90. A ratio within the above range is preferable for the stable dissolution of gallic acid.

[0029] The oil and fat components are not particularly limited, but examples include vegetable oils such as coconut oil, soybean oil, rice oil, corn oil, sesame oil, linseed oil, palm oil, safflower oil, rapeseed oil, olive oil, cocoa butter, coconut oil, and peanut oil; medium-chain triglyceride (MCT) oils in which fatty acids with approximately 8 to 12 carbon atoms (such as capric acid and caprylic acid) are bonded to glycerol; animal fats such as beef tallow, pork tallow, chicken tallow, mutton tallow, and fish oil; fatty acids such as oleic acid; and mixtures thereof. The oil and fat components used may be single or in combination of two or more types. A preferred example is medium-chain triglyceride (MCT), which is less susceptible to oxidation, from the viewpoint of preventing the consumption of antioxidants in the antioxidant composition due to oxidation of the oil and fat components themselves.

[0030] The oil and fat content is typically 2 to 45% by mass, preferably 7 to 30% by mass, and more preferably 15 to 25% by mass, based on the total mass of the antioxidant composition. Having an oil and fat content within this range is preferable for stably dispersing the emulsion particles in the continuous oil phase.

[0031] (C) Other ingredients In addition to the components described above, the antioxidant composition of the present invention may contain other emulsifiers, thickeners, inorganic salts, pH adjusters, preservatives, food additives, etc., as long as they do not interfere with the effects of the present invention.

[0032] (D) Physical properties In the antioxidant composition of the present invention, the particle size of the emulsified particles is not particularly limited, but since it affects the degree of turbidity when blended with oils and fats or oil products, the average emulsified particle size is usually 10 to 2000 nm, preferably 50 to 1500 nm, and more preferably 100 to 1000 nm. The average emulsified particle size can be measured using a laser diffraction particle size distribution device.

[0033] (E) Manufacturing method The antioxidant composition of the present invention can be manufactured according to the following emulsification process. As a typical example, an oily component, a lipophilic emulsifier, and glycerin are mixed to prepare an oil phase mixture 1. Adding glycerin to the oil phase mixture 1 and allowing it to blend with the lipophilic emulsifier beforehand makes it less likely for gallic acid to precipitate. On the other hand, an aqueous phase mixture 2 is prepared by mixing gallic acid, tea catechins, glycerin, and water, and optionally sodium lactate and citric acid. Then, by mixing the aqueous phase mixture 2 with the oil phase mixture 1 and stirring to homogenize the whole, the antioxidant composition of the present invention, which is an oil-in-water droplet type emulsion, can be obtained (see Invention Products 1 and 2 described later). In this case, it is desirable to heat the aqueous phase mixture 2 during preparation and mix and emulsify it with the oil phase mixture 1 before it cools and gallic acid precipitates. The amounts of each component are as described above. The stirring is usually performed at 1500 to 20000 rpm, preferably 3000 to 15000 rpm, and more preferably 4000 to 10000 rpm, and commercially available stirring devices such as homomixers, colloid mills, rotary disc homogenizers, and high-pressure homogenizers can be used. The stirring time is not particularly limited, but is usually 1 to 120 minutes, preferably 2 to 90 minutes, and more preferably 5 to 60 minutes.

[0034] Another example of a manufacturing method involves preparing an oil phase mixture 3 by mixing an oily component, a lipophilic emulsifier, glycerin, gallic acid, and tea catechins. In this case, by incorporating glycerin into the oil phase mixture 3 and allowing it to blend with the lipophilic emulsifier before emulsifying, gallic acid is less likely to precipitate. Meanwhile, an aqueous phase mixture 4 is prepared by mixing water and glycerin, and optionally sodium lactate and citric acid. Then, by mixing the aqueous phase mixture 4 with the oil phase mixture 3 and stirring to homogenize the whole, the aforementioned antioxidant composition of the present invention, which is a water-in-oil emulsion, can be obtained (see Invention Products 3 and 4 described later). The characteristic of this example is that an oil phase mixture is prepared, rather than an aqueous phase mixture containing gallic acid and tea catechins. By preparing an oil phase mixture containing gallic acid and tea catechins and mixing and stirring it with the aqueous phase mixture, an antioxidant composition with higher antioxidant power can be obtained. The proportions of each ingredient and the stirring conditions are as described above.

[0035] In producing the antioxidant composition of the present invention, from the viewpoint of obtaining an antioxidant composition exhibiting a transparent appearance, it is preferable to further include a step of adjusting the ratio of the refractive index of the aqueous phase composition to the refractive index of the oil phase composition so that it is usually 0.5 to 1.5, preferably 0.8 to 1.2, and more preferably 0.9 to 1.1. The timing of adjusting the refractive index ratio is not particularly limited and may be done during the process of preparing the oil-aqueous-fluid mixture described above, or after the mixture has been prepared. The method of adjusting the refractive index ratio is also not particularly limited, but it is preferable to adjust the refractive index ratio by appropriately adjusting the amount of glycerin and water added.

[0036] (F)Application The antioxidant composition of the present invention is added to articles for the purpose of preventing oxidation of oils and fats, suppressing deterioration odors, and especially suppressing deterioration odors caused by thermal deterioration. The articles to which it can be added are not particularly limited and include various oils and fats (edible oils and fats, cosmetic raw material oils and fats, etc.) and oil and fat products (oil-based cooked foods, oil-soluble fragrances, etc.). The amount to be added can be determined as appropriate, but generally, a range of about 0.02 to 0.6% by mass relative to the oil or oil and fat product is used. [Examples]

[0037] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples. Unless otherwise specified, "%" below means "mass%".

[0038] [Test Example 1: Primary Screening: Oxidative Stability Test] A preliminary screening of antioxidants was conducted with the aim of selecting candidate antioxidants that appear to be effective in suppressing the oxidation of oils and fats. Specifically, each sample was prepared by adding various antioxidants shown in Table 1 to soybean oil in the proportions shown in Table 1, and each of these samples was subjected to an oxidation stability test. The oxidation stability test was performed using an oxidation stability tester (RapidOxy100 (product name), manufactured by Anton Paar Japan) under conditions of temperature: 120°C and oxygen pressure: 700kPa, measuring the time (minutes) until 10% of the oxygen pressure was consumed (oxidation induction time). A longer time indicates higher oxidation stability of the sample, or in other words, higher antioxidant power of the antioxidant used. The results are shown in Figure 1. In Figure 1, the components indicated by abbreviations or product names are as follows: Polyphenon 70S: Tea catechins (manufactured by Mitsui Norin Co., Ltd.) VE: Vitamin E VC: Vitamin C Sankator No. 1: Mixed tocopherols (9%), catechin (10%) (manufactured by Taiyo Kagaku Co., Ltd.) Flavor holder GCH: Gallic acid (7%), mixed tocopherols (7%), green coffee bean extract (10.4%) (manufactured by Hasegawa Fragrances Co., Ltd.)

[0039] (Results / Discussion) As can be seen from Figure 1, antioxidants containing polyphenone 70S showed high antioxidant activity. From this, it can be inferred that tea catechins are effective in preventing the oxidation of oils and fats.

[0040] [Test Example 2: Secondary Screening: Carbonyl Value Measurement, and Tertiary Screening: Sensory Evaluation] Based on the results of the initial screening, secondary and tertiary screenings were conducted to determine which antioxidant—Polyphenon 70S alone or an antioxidant containing Polyphenon 70S—was most effective in inhibiting the oxidation of oils and fats. Specifically, each sample was prepared by adding 0.02% (0.02% of each component in the case of a combination product consisting of two components) of various antioxidants (No. 3-10) shown in Table 1 to soybean oil. Next, simulating summer conditions, the samples were stored at 40°C for two weeks. After that, the carbonyl value (CV) of each sample was measured (secondary screening). The carbonyl value was measured according to the conventional 2,4-DNPH method. That is, 1 ml of butanol solution containing 5 mg of the sample was reacted with 1 ml of 2,4-dinitrophenylhydrazine solution acidified with hydrochloric acid at 40°C for 20 minutes, and the absorbance at 420 nm based on the 2,4-dinitrophenylhydrazone produced in this reaction was measured. The amount of carbonyl compound was calculated from a calibration curve prepared using 2-decenal as the standard, and the amount of carbonyl compound per gram of sample (μmol) was defined as the carbonyl value. A higher carbonyl value indicates that the sample is more oxidized; in other words, it means that the antioxidant used has low antioxidant power. The results are shown in Table 1. Furthermore, each of the prepared samples was shaken at 50°C and 200 rpm for two weeks, after which a sensory evaluation was performed on each sample (corresponding to No. 2 to 10) (third screening). The sensory evaluation was conducted by 10 well-trained panelists with more than 10 years of experience. During the evaluation, they were asked to freely comment on the odors they perceived. Table 1 shows representative comments from the 10 panelists.

[0041] [Table 1]

[0042] (result) As can be seen from Table 1, the sample containing polyphenon 70S + gallic acid (No. 8) showed good results in both carbonyl value and sensory evaluation. From this, it can be inferred that the combination of tea catechins and gallic acid is the most effective in preventing oxidation of oils and fats and suppressing off-odors.

[0043] [Test Example 3: Confirmation of the clarification effect of adding glycerin to the aqueous phase of an antioxidant composition] An antioxidant composition containing glycerin in the aqueous phase was prepared, and the clarification effect of glycerin on the antioxidant composition was investigated. First, an antioxidant composition with the composition shown in Table 2 was prepared according to the following (Preparation of Antioxidant Composition) (Product 1 of the Invention). Figure 2 shows a photograph of the prepared Product 1 of the Invention as observed visually. Table 2 also shows the results of measuring the refractive indices of the oil phase and the aqueous phase (corresponding to the oil phase and aqueous phase portions of Product 1 of the Invention, respectively). Furthermore, the oxidation stability test shown in Test Example 1 was similarly performed on Product 1 of the Invention. On the other hand, an antioxidant composition (control product 1) with the same composition as product 1 of the present invention was prepared, except that glycerin was not included in the aqueous phase (0g). Figure 3 shows a photograph of the prepared control product 1 as observed visually. Table 2 shows the results of measuring the refractive indices of the oil phase and aqueous phase (corresponding to the oil phase and aqueous phase of control product 1, respectively). Furthermore, the oxidation stability test shown in Test Example 1 was performed on control product 1 in the same manner. (Preparation of antioxidant composition) (1) Mix the oil phase components shown in Table 2, namely the emulsifier (SY Glister CRS-75, trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd.), MCT, and glycerin uniformly in the amounts shown in Table 2. (2) Mix the aqueous phase components shown in Table 2, namely water, glycerin, gallic acid, and tea catechins, uniformly in the amounts shown in Table 2. (3) Add the aqueous phase mixture from (2) to the oil phase mixture from (1) and stir in a TK homomixer at 8000 rpm for 5 minutes.

[0044] [Table 2]

[0045] (result) As can be seen from the comparison in Figures 2 and 3, the incorporation of glycerin into the aqueous phase resulted in Product 1 of the present invention becoming a transparent water-in-oil type emulsifier. Furthermore, the oxidation induction time in the oxidation stability test for Product 1 was 146 minutes. On the other hand, the oxidation induction time in the oxidation stability test for Control Product 1 was 110 minutes. From this, it can be inferred that glycerin contributes to emulsion stability and the stable dissolution of gallic acid. Furthermore, regarding the refractive index, Product 1 of the present invention showed a smaller difference in refractive index between the oil phase and the water phase compared to Control Product 1, resulting in a more transparent water-in-oil emulsion formulation. From this, it can be inferred that a transparent and stable antioxidant composition can be obtained by adjusting the refractive index of the oil phase and the water phase to the same value.

[0046] [Test Example 4: Confirmation of the effect of reducing the amount of glycerin in the aqueous phase of an antioxidant composition on improving handling] An antioxidant composition with a reduced amount of glycerin in the aqueous phase was prepared, and the effect of reducing the viscosity of the antioxidant composition on improving handling was investigated. First, an antioxidant composition with the composition shown in Table 3 was prepared according to the following (Preparation of Antioxidant Composition) (Product 2 of the Invention). Figure 4 shows a photograph illustrating the appearance of the prepared Product 2 of the Invention as observed visually. Table 3 shows the results of measuring the refractive indices of the oil phase and the aqueous phase (corresponding to the oil phase and aqueous phase portions of Product 2 of the present invention, respectively). Furthermore, the oxidation stability test shown in Test Example 1 was performed on Product 2 of the present invention in the same manner. In addition, the viscosity of Products 1 and 2 of the present invention at 25°C was measured (viscosity measurement method: Type B viscometer (manufactured by Tokyo Keiki Co., Ltd.), rotor No. 3, 20°C, 60 rpm, 1 minute). (Preparation of antioxidant composition) (1) Mix the oil phase components shown in Table 3, namely the emulsifier (SY Glister CRS-75, trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd.), MCT, and glycerin uniformly in the amounts shown in Table 3. (2) Mix the aqueous phase components shown in Table 3, namely water, glycerin, gallic acid, tea catechins, 50% sodium lactate, and citric acid, uniformly in the amounts shown in Table 3. (3) Add the aqueous phase mixture from (2) to the oil phase mixture from (1) and stir in a TK homomixer at 8000 rpm for 5 minutes.

[0047] [Table 3]

[0048] (result) As can be seen from Figure 4, by reducing the amount of glycerin in the aqueous phase compared to Product 1 of the present invention, and by incorporating sodium lactate and citric acid, Product 2 of the present invention became a transparent water-in-oil type emulsifier. Furthermore, while the viscosity of Product 1 of the present invention was 500 mPa·s, the viscosity of Product 2 of the present invention was 600 mPa·s, indicating improved handling of Product 2 compared to Product 1. In addition, the oxidation induction time in the oxidation stability test for Product 2 of the present invention was 183 minutes. From this, it is inferred that sodium lactate contributes to emulsion stability and the stable dissolution of gallic acid, and that the combined use of citric acid prevents a decrease in antioxidant capacity due to gallic acid becoming gallate.

[0049] [Test Example 5: Confirmation of the antioxidant effect of an antioxidant composition by mixing and emulsifying an oil phase containing gallic acid and tea catechins with an aqueous phase.] The antioxidant effect of an antioxidant composition prepared by mixing and emulsifying an oil phase containing gallic acid and tea catechins with an aqueous phase was investigated. First, an antioxidant composition with the composition shown in Table 4 was prepared according to the following (Preparation of Antioxidant Composition) (Product 3 of the Invention). Figure 5 shows a photograph of the prepared Product 3 of the Invention as observed visually. Table 4 shows the results of measuring the refractive indices of the oil phase and the aqueous phase. Furthermore, the oxidation stability test shown in Test Example 1 was performed on Product 3 of the Invention in the same manner. (Preparation of antioxidant composition) (1) The oil phase components shown in Table 4, namely the emulsifier (SY Glister CRS-75, trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd.), MCT, glycerin, gallic acid, and tea catechins, are uniformly mixed in the amounts shown in Table 4. (2) Mix the aqueous phase components shown in Table 4, namely water and glycerin, uniformly in the amounts shown in Table 4. (3) Add the aqueous phase mixture from (1) to the oil phase mixture from (1) and stir in a TK homomixer at 8000 rpm for 5 minutes.

[0050] [Table 4]

[0051] (result) As can be seen from Figure 5, when gallic acid and tea catechins were added to the oil phase, product 3 of the present invention became a transparent water-in-oil emulsion. Furthermore, the oxidation induction time in the oxidation stability test was 174 minutes. From this, it can be inferred that adding gallic acid and tea catechins to the oil phase increases the antioxidant power of the resulting antioxidant composition.

[0052] [Test Example 6: Confirmation of the antioxidant effect of an antioxidant composition by mixing and emulsifying an oil phase containing gallic acid and tea catechins with an aqueous phase containing sodium lactate and citric acid.] The antioxidant effect of an antioxidant composition prepared by mixing and emulsifying an oil phase containing gallic acid and tea catechins with an aqueous phase containing sodium lactate and citric acid was investigated. First, an antioxidant composition with the composition shown in Table 5 was prepared according to the following (Preparation of Antioxidant Composition) (Product 4 of the Invention). Figure 6 shows a photograph of the prepared Product 4 of the Invention as observed visually. Table 5 shows the results of measuring the refractive indices of the oil phase and the aqueous phase. Furthermore, the oxidation stability test shown in Test Example 1 was performed on Product 4 of the Invention in the same manner. (Preparation of antioxidant composition) (1) Mix the oil phase components shown in Table 5, namely the emulsifier (SY Glister CRS-75, trade name, manufactured by Sakamoto Pharmaceutical Co., Ltd.), MCT, glycerin, gallic acid, and tea catechins, uniformly in the amounts shown in Table 5. (2) Mix the aqueous phase components shown in Table 5, namely water, glycerin, 50% sodium lactate, and citric acid, uniformly in the amounts shown in Table 5. (3) Add the aqueous phase mixture from (1) to the oil phase mixture from (1) and stir in a TK homomixer at 8000 rpm for 5 minutes.

[0053] [Table 5]

[0054] (result) As can be seen from Figure 6, when an oil phase containing gallic acid and tea catechins was mixed and emulsified with an aqueous phase containing sodium lactate and citric acid, product 4 of the present invention became a transparent water-in-oil emulsion. Furthermore, the oxidation induction time in the oxidation stability test was 194 minutes. From this, it can be inferred that when an oil phase containing gallic acid and tea catechins is mixed and emulsified with an aqueous phase containing sodium lactate and citric acid, the antioxidant power of the resulting antioxidant composition is significantly increased.

[0055] [Test Example 7: Sensory Evaluation of Products 1-4 of the Invention] Sensory evaluation was performed on products 1-4 of the present invention, as described above, in the same manner as in Test Example 2. During the evaluation, participants were asked to freely comment on the perceived odors. Table 6 shows representative comments from the 10 panelists. The oxidation induction time (indicated as antioxidant capacity in the table) from the oxidation stability test described above is also summarized in Table 6.

[0056] [Table 6]

[0057] (Results / Discussion) As can be seen from Table 6, the sensory evaluation of products 1 to 4 of the present invention showed favorable results that correlated with antioxidant capacity. From this, it can be understood that the products of the present invention are effective in preventing oxidation of oils and fats and suppressing off-odors.

Claims

1. An oil-in-oil droplet type oil-soluble antioxidant composition in which an aqueous phase containing gallic acid, tea catechins, glycerin, and water is emulsified in an oil phase containing a lipophilic emulsifier, glycerin, and oil components, An oil-soluble antioxidant composition characterized by not containing oil-soluble antioxidants.

2. The oil-soluble antioxidant composition according to claim 1, comprising gallic acid and tea catechins in a mass ratio of 1:0.1 to 3.

0.

3. The oil-soluble antioxidant composition according to claim 1, wherein the aqueous phase further comprises sodium lactate and citric acid.

4. The oil-soluble antioxidant composition according to claim 3, comprising sodium lactate and citric acid in a mass ratio of 1:0.2 to 2.

0.

5. The oil-soluble antioxidant composition according to claim 1, wherein the appearance is transparent.

6. An oil-soluble antioxidant composition according to claim 1, for suppressing the deterioration odor of oils and fats caused by thermal degradation.

7. The following steps: 1) A step of preparing an oil phase mixture containing an oily component, a lipophilic emulsifier, and glycerin. 2) A step of preparing an aqueous phase mixture containing gallic acid, tea catechins, glycerin, and water. 3) Adding the aqueous phase mixture from 2) to the oil phase mixture from 1) to emulsify it into a water droplet type in oil, A method for producing an oil-soluble antioxidant composition, characterized by containing [a certain substance].

8. The following steps: 1) A step of preparing an oil phase mixture containing an oily component, a lipophilic emulsifier, glycerin, gallic acid, and tea catechins. 2) A step of preparing an aqueous phase mixture containing water and glycerin, 3) Adding the aqueous phase mixture from 2) to the oil phase mixture from 1) to emulsify it into a water droplet type in oil, A method for producing an oil-soluble antioxidant composition, characterized by containing [a certain substance].

9. A method for producing an oil-soluble antioxidant composition according to claim 7 or 8, further comprising the step of adjusting the ratio of the refractive index of the aqueous phase mixture to the refractive index of the oil phase mixture to be 0.5 to 1.5.

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