Oil-in-water-type emulsion and method for producing same

Abstract

The purpose of the present invention is to provide an oil-in-water-type emulsion that, by simply adding a small amount thereof, is capable of imparting an oily taste that is a flavor characteristic, such as fat-like richness or fat-like body, and reducing bitterness.　It has been found that it is possible to impart an oily taste that is a flavor characteristic, such as fat-like richness or fat-like body, and reduce bitterness, even when a free fatty acid is contained, by using an oil-in-water-type emulsion that contains an oily material containing a free fatty acid, an easily water-soluble substance, water, and a protein material having specific properties, and that has an emulsion particle size of at most 100 nm.

Description

Oil-in-water emulsion and method for producing the same

[0001] The present invention relates to an oil-in-water emulsion and a method for producing the same.

[0002] With the recent rise in health consciousness, there is a strong market demand for low-fat foods. However, low fat content significantly impacts taste, such as a feeling of lack of flavor, and there is a strong desire to improve this, i.e., to increase richness. In recent years, plant-based foods, such as vegan diets and plant-based foods, have been attracting attention. Compared to animal-based foods, these foods are often rated as having a lighter flavor, even when they contain the same amount of fat, and there is a demand for improved richness. Here, richness and richness refer to a group of flavor elements not included in the five basic tastes, and one of the important elements is oiliness. Oiliness is a taste that is also called the sixth taste, in which receptors detect oil and fat itself, and is also referred to as oily or greasy taste. In this specification, oiliness is used in this sense. Note that oiliness is separate from the aroma components contained in oils and the odor that arises due to the deterioration of lipids.

[0003] Ingested food is broken down by various digestive fluids in the digestive tract and absorbed into the body, primarily participating in biological reactions at biomembranes. During the digestive process from ingestion to absorption, food is transported as oil-in-water emulsion particles. In particular, just before absorption, particle size is thought to decrease, from nanoemulsions with nanometer-sized particles to mixed micelles. High uptake of functional ingredients into mixed micelles is considered high bioavailability. Functional food ingredients, including polyphenols and carotenoids, are known to be effective in maintaining health and preventing disease. However, many of them are unstable to heat, light, and oxygen, and many are lipid-soluble, meaning they have low bioavailability. Emulsification is known to improve the bioavailability of lipid-soluble functional food ingredients. Furthermore, smaller emulsion particle sizes are associated with improved absorption. This holds true for the energy efficiency of fats and oils, regardless of the functional food ingredient. Thus, ingestion of nanoemulsions can have a beneficial effect on survival.

[0004] Various methods have been investigated for oily taste enhancers. Patent Document 2 proposes a method of incorporating an oil-in-water emulsified oil having an average emulsion particle size of 2 μm to 15 μm into a food product containing a smaller amount of oil than conventionally used. Patent Document 3 proposes a flavor improver for low-fat foods containing (E)-6-octenal as an active ingredient. Patent Document 4 proposes a method of improving the persistence of the flavor of edible oils in the mouth when ingested by incorporating a polyglycerol condensed ricinoleic acid ester into the edible oil. Patent Document 5 proposes a flavor improver for foods and beverages containing free oleic acid as an active ingredient. Patent Document 6 proposes an emulsion containing a free long-chain fatty acid or its salt and an emulsifier.

[0005] PCT / JP2023 / 003285 JP 2012-170449 A JP 2018-22 A JP 2022-22986 A JP 2011-223942 A WO2010 / 035704 A

[0006] The present inventors have discovered that incorporating an oil-in-water nanoemulsion containing a specific protein ingredient into food can improve the oily taste of the food and, simply put, make the food more delicious (Patent Document 1). However, nanoemulsions require specialized emulsification equipment, which poses cost challenges, and improvements in their functionality are desirable. Furthermore, the technologies described in Patent Documents 2 and 4 are insufficiently effective as oily taste enhancers. Furthermore, Patent Document 3 deals with flavorings, but given the current market environment's shunning of synthetic compounds, methods that do not use flavorings are desired. Furthermore, because flavorings are not inherently lipid-constituting elements, the flavors imparted by these methods are not essential. Furthermore, there are specified limits for the amount of additives, and unintended increases or decreases in the amount can limit the scope of application depending on the food processing and storage method. Furthermore, Patent Document 5 describes the effect as follows: "The present invention can mask the unpleasant aftertaste and sticky feeling that are characteristic of vegetable oils and fats, particularly those strongly associated with hardened oils and fats, such as hydrogenation odor, off-flavor, and hardened odor." The objective is not to enhance the oily taste. Furthermore, the technology of Patent Document 6 has the drawback that emulsions containing free fatty acids are extremely bitter, and therefore, in order to achieve a satisfactory effect, a bitter taste must be produced. Therefore, the present invention aims to provide an oil-in-water emulsion that can impart an oily taste, which is a flavor characteristic such as a fat-like richness or fat-like body, with only a small amount of addition, while suppressing the bitterness.

[0007] As a result of extensive research to solve the above problems, the present inventors have found that by using an oil-in-water emulsion containing an oily material containing free fatty acids, a water-soluble substance, water, and a protein material having specific properties, and having an emulsion particle size of 100 nm or less, an oily taste such as a fatty-like richness or body can be imparted, and bitterness can be suppressed despite the use of free fatty acids, thereby completing the present invention.

[0008] That is, the present invention provides: (1) an oil-in-water emulsion comprising an oily material, a water-soluble substance, water, and a protein material, having an emulsion particle size of 100 nm or less, and satisfying the following requirements (A) and (B): (A) the oily material comprises at least free fatty acids; (B) the protein material has a viscosity of 10,000 mPa s or less when measured at 25°C after heating an aqueous solution containing 20% ​​by weight of crude protein at 80°C for 30 minutes, and a 0.22M TCA solubilization rate of 30% to 95%; (2) the oil-in-water emulsion according to (1), wherein the free fatty acids are one or more selected from oleic acid, linoleic acid, palmitic acid, and stearic acid; (3) An oil-in-water emulsion according to (1), which contains 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material, and in (A), the oily material contains 1 to 99% by mass of free fatty acids; (4) An oil-in-water emulsion according to (2), which contains 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material, and in (A), the oily material contains 1 to 99% by mass of free fatty acids; (5) An oil-in-water emulsion according to (3), which contains 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material, and in (A), the oily material contains 1 to 99% by mass of free fatty acids and 1 to 99% by mass of fats and oils; (6) An oil-in-water emulsion according to (3), which contains 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material;The oil-in-water emulsion according to (4), which contains 5 to 35% by mass of a readily water-soluble substance, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein of the oily material, and in (A), the oily material contains 1 to 99% by mass of free fatty acids and 1 to 99% by mass of fats and oils; (7) The oil-in-water emulsion according to (1), wherein the protein material has an NSI of 80 or more; (8) The oil-in-water emulsion according to (2), wherein the protein material has an NSI of 80 or more; (9) The oil-in-water emulsion according to (3), wherein the protein material has an NSI of 80 or more; (10) The oil-in-water emulsion according to (4), wherein the protein material has an NSI of 80 or more; (11) The oil-in-water emulsion according to (5), wherein the protein material has an NSI of 80 or more; (12) The oil-in-water emulsion according to (6), wherein the protein material has an NSI of 80 or more; (13) The oil-in-water emulsion according to (1), wherein the water content is 65% by mass or less; (14) The oil-in-water emulsion according to (2), wherein the water content is 65% by mass or less; (15) The oil-in-water emulsion according to (1), wherein the oil-based material further contains an L-ascorbic acid fatty acid ester; (16) The oil-in-water emulsion according to (2), wherein the oil-based material further contains an L-ascorbic acid fatty acid ester; (17) The oil-in-water emulsion according to (1), which is plant-based; (18) The oil-in-water emulsion according to (2), which is plant-based; (19) The protein material accounts for 30 to 1,200% by mass of the oil-based material in terms of crude protein, and 1 to 80% by mass of the water-soluble substance; and a method for producing an oil-in-water emulsion having an emulsion particle size of 100 nm or less, which comprises mixing 0.5 to 35% by mass of an oily material containing free fatty acids with a solution of 5 to 70% by mass of water and applying shear force; (20) A method for producing an oil-in-water emulsion having an emulsion particle size of 100 nm or less, which comprises heating an aqueous solution of 20% by mass of crude protein at 80°C for 30 minutes, and then measuring the viscosity at 25°C to be 10,000 mPa s or less, and 0.(19) A method for producing an oil-in-water emulsion, wherein the TCA solubilization rate of 22M is 30 to 95% and the NSI is 80 or more; (21) A food or drink comprising the oil-in-water emulsion according to (1); (22) A food or drink comprising the oil-in-water emulsion according to (2); (23) An agent for imparting an oily taste to a food or drink, comprising the oil-in-water emulsion according to (1); (24) An agent for imparting an oily taste to a food or drink, comprising the oil-in-water emulsion according to (2). In other words, the present invention provides: (1) an oil-in-water emulsion comprising an oily material, a water-soluble substance, water, and a protein material, having an emulsion particle size of 100 nm or less, and satisfying the following requirements (A) and (B): (A) the oily material comprises at least free fatty acids; (B) the protein material has a viscosity of 10,000 mPa s or less when measured at 25°C after heating an aqueous solution containing 20% ​​by weight of crude protein at 80°C for 30 minutes, and a 0.22M TCA solubilization rate of 30% to 95%; (2) the oil-in-water emulsion according to (1), wherein the free fatty acids are one or more selected from oleic acid, linoleic acid, palmitic acid, and stearic acid; (3) An oil-in-water emulsion according to (1) or (2), which contains 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material, and in (A), the oily material contains 1 to 99% by mass of free fatty acids; (4) An oil-in-water emulsion according to (1) or (2), which contains 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material;(5) The oil-in-water emulsion according to (3), which contains 5 to 35% by mass of a water-soluble substance, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein of the oily material, and in (A), the oily material contains 1 to 99% by mass of free fatty acids and 1 to 99% by mass of fats and oils; (5) The oil-in-water emulsion according to (1), in which the protein material has an NSI of 80 or more; (6) The oil-in-water emulsion according to (2), in which the protein material has an NSI of 80 or more; (7) The oil-in-water emulsion according to (1), in which the water content is 65% by mass or less; (8) The oil-in-water emulsion according to (2), in which the water content is 65% by mass or less; (9) The oil-in-water emulsion according to (1) or (2), in which the oily material further contains an L-ascorbic acid fatty acid ester; (10) The oil-in-water emulsion according to (1) or (2), which is plant-based; (11) A method for producing an oil-in-water emulsion having an emulsion particle size of 100 nm or less, which comprises mixing 0.5 to 35 mass% of an oily material containing free fatty acids with a solution of the protein material, in terms of crude protein content, 30 to 1,200 mass% of an oily material, 1 to 80 mass% of a water-soluble substance, and 5 to 70 mass% of water, and applying shear force; (12) A method for producing the oil-in-water emulsion according to (11), wherein the protein material has a viscosity of 10,000 mPa s or less when measured at 25°C after heating an aqueous solution of 20 mass% crude protein at 80°C for 30 minutes, a 0.22M TCA solubilization rate of 30 to 95%, and an NSI of 80 or more; (13) A food or drink containing the oil-in-water emulsion according to (1) or (2); (14) An oily taste imparting agent for foods and beverages, comprising the oil-in-water emulsion according to (1) or (2).

[0009] The present invention makes it possible to impart an oily taste to a wide range of aqueous foods, thereby contributing to improved taste and health promotion.

[0010] (Oil-in-water emulsion) The oil-in-water emulsion of the present invention comprises an oily material, a water-soluble substance, water, and a protein material, has an emulsion particle size of 100 nm or less, and satisfies the following requirements (A) and (B): (A) the oily material contains at least free fatty acids; (B) the protein material has a viscosity of 10,000 mPa·s or less when measured at 25°C after heating an aqueous solution containing 20% ​​by weight of crude protein at 80°C for 30 minutes, and a 0.22M TCA solubilization rate of 30% to 95%. As described above, the oil-in-water emulsion of the present invention contains free fatty acids, which have the effect of enhancing the oily taste, and the inclusion of free fatty acids in the oil-in-water emulsion of the above configuration also exerts the effect of suppressing the bitterness derived from the free fatty acids. In one embodiment, the oil-in-water emulsion of the present invention can be a plant-based oil-in-water emulsion produced primarily from plant ingredients, thereby improving the fatty taste of foods and beverages without using animal-derived foods. The proportion of plant ingredients in the solids of the plant-based oil-in-water emulsion is preferably 50% by mass or more, more preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass or more. In the present invention, "fatty taste" refers to the richness and full-bodied flavor felt when consuming fats and oils. This "fatty taste" is also known as the sixth taste, in which receptors sense the fats and oils themselves. Furthermore, the emulsion particle size of the oil-in-water emulsion of the present invention is 100 nm or less, and by setting the emulsion particle size to 100 nm or less, an excellent effect of improving the fatty taste can be achieved. The emulsion particle size of the oil-in-water emulsion is preferably 95 nm or less, and more preferably 93 nm or less, 90 nm or less, 85 nm or less, 80 nm or less, 75 nm or less, 70 nm or less, 65 nm or less, or 60 nm or less.

[0011] (Oil-Based Ingredients) The oil-based ingredients of the present invention refer to substances that are insoluble or poorly soluble in water but readily soluble in neutral lipids, as well as lipids themselves. Examples of oil-based ingredients of the present invention include vegetable oils such as soybean oil, rapeseed oil, corn oil, safflower oil, rice oil, cottonseed oil, sunflower oil, high oleic sunflower oil, sesame oil, olive oil, peanut oil, palm oil, palm kernel oil, and coconut oil; animal oils such as lard, beef tallow, and fish oil; medium-chain fatty acid oils; and oils modified by transesterification, hydrogenation, or the like, and free fatty acids. In some embodiments, vegetable oils are preferably used as the oil-based ingredients of the present invention to produce vegetable-based oil-in-water emulsions. The lower limit of the amount of oil in the oil-based ingredients of the present invention is preferably 1% by mass or more, more preferably 3% by mass or more. More preferably, the amount of oil or fat in the oil-based material of the present invention is 5% by mass or more, 10% by mass or more, 20% by mass or more, 30% by mass or more, 40% by mass or more, 45% by mass or more, 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more, or 70% by mass or more. The upper limit of the amount of oil or fat in the oil-based material of the present invention is preferably 99% by mass or less, more preferably 97% by mass or less. It is even more preferably 95% by mass or less, 93% by mass or less, 91% by mass or less, or 90% by mass or less. These lower and upper limits can be combined in any way. Examples include 1 to 99% by mass, 20 to 95% by mass, and 50 to 95% by mass.

[0012] (Free Fatty Acids) The present invention is characterized by including free fatty acids in the oil-based material. By including free fatty acids, an oily taste can be improved. The lower limit of the amount of free fatty acids in the oil-based material of the present invention is preferably 1% by mass or more, more preferably 2% by mass or more. It can be even more preferably 3% by mass or more, 5% by mass or more, or 7% by mass or more. The upper limit of the amount of free fatty acids in the oil-based material of the present invention is preferably 99% by mass or less, more preferably 95% by mass or less. It can be even more preferably 90% by mass or less, 70% by mass or less, 50% by mass or less, 40% by mass or less, 35% by mass or less, 30% by mass or less, 25% by mass or less, or 20% by mass or less. These lower and upper limits can be combined in any manner. Examples include 1-99% by mass, 1-50% by mass, 2-40% by mass, 3-30% by mass, and 5-20% by mass. In the present invention, examples of free fatty acids include polyunsaturated fatty acids such as lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, stearic acid, eicosapentaenoic acid, docosahexaenoic acid, arachidonic acid, and γ-linolenic acid. Among these, oleic acid, linoleic acid, palmitic acid, and stearic acid are preferred, with oleic acid and linoleic acid being even more preferred from the viewpoints of improving oily taste and suppressing bitterness. These free fatty acids can be used alone or in combination of two or more. The free fatty acids may be chemically synthesized or may be hydrolysates of edible oils and fats. Furthermore, mixtures of other oily materials with free fatty acids are also possible. In the case of edible oil hydrolysates, the origin of the edible oil is not limited, and examples include soybean oil, rapeseed oil, corn oil, safflower oil, rice oil, cottonseed oil, sunflower oil, high oleic sunflower oil, sesame oil, olive oil, peanut oil, palm oil, palm kernel oil, coconut oil, lard, beef tallow, fish oil, and medium-chain fatty acid oils. Furthermore, hydrolysis can be performed using enzymatic hydrolysis, chemical hydrolysis, or hydrolysis at high temperature or high pressure. Hydrolysis using lipase is preferred as the hydrolysis method. Furthermore, in one embodiment, to produce a vegetable-based oil-in-water emulsion, a vegetable oil hydrolysate can be preferably used as the oily ingredient of the present invention.The hydrolysate may contain monoglycerin or diglycerin, but the amount of free fatty acids in the hydrolysate is preferably 50% by mass or more, more preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, or even 95% by mass or more.

[0013] (Protein Material) The protein material used in the present invention must have a low viscosity after heating (hereinafter referred to as "post-heating viscosity"). The post-heating viscosity can be measured by preparing an aqueous solution of the protein material with a crude protein content of 20% by mass, heating it at 80°C for 30 minutes, and then measuring the viscosity at 25°C. The post-heating viscosity is 10,000 mPa·s or less, preferably 5,000 mPa·s or less, 1,000 mPa·s or less, or 500 mPa·s or less, and more preferably 200 mPa·s or less, or 100 mPa·s or less. Furthermore, the protein material must have a certain molecular weight. The molecular weight is defined by the TCA solubilization rate. In the present invention, the TCA solubilization rate is defined as the ratio of the amount of crude protein dissolved in 0.22 M TCA to the total amount of crude protein. The TCA solubilization rate of the protein material is 30 to 95%. Preferably, the TCA solubilization rate can be 35-90%, 40-85%, 45-80%, or 50-80%. If the TCA solubilization rate is too low, the viscosity tends to increase after heating, which may be inappropriate. It may also decrease transmittance. On the other hand, if the TCA solubilization rate is too high, the amount of protein contributing to emulsification decreases, necessitating the incorporation of a larger amount of protein material, which may reduce the flexibility of formulation. The protein material preferably has an NSI (Nitrogen Solubility Index), used as an index of protein solubility, of 80 or more. More preferably, NSI values ​​of 85 or more, 90 or more, 95 or more, or 97 or more can be used. A high NSI of a protein material indicates high dispersibility in water and can contribute to the dispersion stability of the oil-in-water emulsion composition of the present invention. Furthermore, the crude protein content of the protein material is preferably 30% by mass or more. More preferably, the crude protein content can be 35% by mass or more, 40% by mass or more, 45% by mass or more, 50% by mass or more, 55% by mass or more, 60% by mass or more, 65% by mass or more, or 70% by mass or more. Protein materials with a higher crude protein content can provide their function in smaller amounts. An example of such a protein material is "MIRA-MAP 2.0" manufactured by Fuji Oil.

[0014] The origin of the protein material to be prepared as described above is not particularly limited, and proteins of vegetable, animal, or microbial origin can be used. Examples of vegetable proteins include proteins derived from beans such as soybeans, peas, mung beans, lupine beans, chickpeas, kidney beans, lentil beans, and cowpeas; seeds such as sesame, canola seeds, coconut seeds, and almond seeds; grains such as corn, buckwheat, wheat, and rice; vegetables; fruits; algae; and microalgae. For example, soybean-derived protein materials are prepared by further concentrating and processing soybean raw materials such as defatted soybeans and whole soybeans, and generally include soy protein isolates, concentrated soy protein, powdered soy milk, and various processed versions of these. Examples of animal proteins include egg proteins including egg albumin, milk proteins such as casein, whey, lactalbumin, and lactalbumin, blood proteins such as plasma, serum albumin, and decolorized hemoglobin, proteins derived from livestock meat, and proteins derived from seafood. Proteins derived from microorganisms such as yeast, mold, and bacteria can also be used. Even proteins with poor water solubility can be prepared into protein materials usable in the present invention by the treatment described below. In addition, in one embodiment, vegetable proteins are preferably used as the protein material of the present invention to produce a vegetable-based oil-in-water emulsion.

[0015] (Denaturation and Molecular Weight Adjustment Treatments) The protein material used in the oil-in-water emulsion of the present invention can be obtained by combining a "decomposition / denaturation treatment" that decomposes and / or denatures a protein with a "molecular weight distribution adjustment treatment" that adjusts the molecular weight distribution of the protein. Examples of the "decomposition / denaturation treatment" include enzyme treatment, pH adjustment treatment (e.g., acid treatment, alkali treatment), denaturant treatment, heat treatment, cooling treatment, high-pressure treatment, organic solvent treatment, mineral addition treatment, supercritical treatment, ultrasonic treatment, electrolysis treatment, and combinations thereof. Examples of the "molecular weight distribution adjustment treatment" include filtration, gel filtration, chromatography, centrifugation, electrophoresis, dialysis, and combinations thereof. The order and number of times of the "decomposition / denaturation treatment" and the "molecular weight distribution adjustment treatment" are not particularly limited, and the "decomposition / denaturation treatment" may be performed before the "molecular weight distribution adjustment treatment," or the "molecular weight distribution adjustment treatment" may be performed before the "decomposition / denaturation treatment," or both treatments may be performed simultaneously. Furthermore, for example, it is possible to perform a "decomposition / modification treatment" between two or more "molecular weight distribution adjustment treatments," to perform a "molecular weight distribution adjustment treatment" between two or more "decomposition / modification treatments," or to perform each treatment multiple times in any order. Note that if the desired molecular weight distribution can be obtained by the "decomposition / modification treatment," the "molecular weight distribution adjustment treatment" does not need to be performed. When these treatments are combined and performed multiple times, all treatments starting from the raw material may be performed continuously, or may be performed after a certain interval. For example, a commercially available product that has undergone a certain treatment may be used as a raw material and subjected to another treatment. Note that, as long as the above-mentioned properties are satisfied, a specific protein material may be prepared by mixing a protein material that has undergone a molecular weight distribution adjustment treatment with a protein material that has not undergone a molecular weight distribution adjustment treatment. In this case, the ratio of the two (treated protein material:untreated protein material) can be adjusted as appropriate within a range that satisfies the above-mentioned properties, and examples of such ratios include a mass ratio of 1:99 to 99:1, 50:50 to 95:5, or 75:25 to 90:10. In one embodiment, the protein material used in the oil-in-water emulsion of this embodiment is a protein material that has been subjected to a "degradation / denaturation and molecular weight distribution adjustment treatment."

[0016] Those skilled in the art can appropriately determine the conditions for the treatment of degrading or denaturing proteins, such as the type and concentration of enzymes, pH, organic solvents, minerals, etc., temperature, pressure, output intensity, current, and time. In the case of enzymes, examples of enzymes that can be used include proteases classified as "metalloproteases," "acid proteases," "thiol proteases," and "serine proteases." The reaction can be carried out at a temperature of 20 to 80°C, preferably 40 to 60°C. In the case of pH adjustment treatment, the treatment can be carried out within a pH range with any of the following upper and lower limits: pH 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, and 12, for example, within a pH range of 2 to 12. In the case of acid treatment, either an acid addition method or a fermentation method such as lactic acid fermentation may be used. Examples of acids to be added include inorganic acids such as hydrochloric acid and phosphoric acid, and organic acids such as acetic acid, lactic acid, citric acid, gluconic acid, phytic acid, sorbic acid, adipic acid, succinic acid, tartaric acid, fumaric acid, malic acid, and ascorbic acid. Acid may also be added using acid-containing foods and beverages such as lemon juice, concentrated fruit juice, fermented milk, yogurt, and brewed vinegar. For alkali treatment, alkalis such as sodium hydroxide and potassium hydroxide may be added. For denaturant treatment, denaturants such as guanidine hydrochloride, urea, arginine, and PEG may be added. For heating or cooling treatment, examples of heating temperatures include a range of 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, and 150°C, for example, 60°C to 150°C. Examples of cooling temperatures include a range with any of the following temperatures as upper and lower limits: −10° C., −15° C., −20° C., −25° C., −30° C., −35° C., −40° C., −45° C., −50° C., −55° C., −60° C., −65° C., −70° C., and −75° C., for example, −10° C. to −75° C. Examples of heating or cooling times include a range with any of the following times as upper and lower limits: 5 seconds, 10 seconds, 30 seconds, 1 minute, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, 100 minutes, 120 minutes, 150 minutes, 180 minutes, and 200 minutes, for example, 5 seconds to 200 minutes.In the case of high-pressure treatment, examples of pressure conditions include a range of pressures, with upper and lower limits being any of 100 MPa, 200 MPa, 300 MPa, 400 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa, 900 MPa, and 1,000 MPa, for example, 100 MPa to 1,000 MPa. In the case of organic solvent treatment, examples of solvents used include alcohols and ketones, such as ethanol and acetone. In the case of mineral addition treatment, examples of minerals used include divalent metal ions such as calcium and magnesium. In the case of supercritical treatment, for example, treatment can be performed using carbon dioxide in a supercritical state at a temperature of about 30°C or higher and a pressure of about 7 MPa or higher. In the case of ultrasonic treatment, for example, treatment can be performed by irradiation with a frequency of 100 kHz to 2 MHz and an output of 100 to 1,000 W. In the case of electrolysis treatment, for example, treatment can be performed by applying a voltage of 100 mV to 1,000 mV to an aqueous protein solution. In a specific embodiment, the treatment that degrades and / or denatures proteins is selected from denaturant treatment, heat treatment, and combinations thereof.

[0017] The conditions for the treatment to adjust the molecular weight distribution of proteins, such as the type of filter medium, gel filtration carrier, centrifugation rotation speed, current, time, etc., can be appropriately determined by those skilled in the art. Examples of filter medium include filter paper, filter cloth, diatomaceous earth, ceramic, glass, membrane, etc. Examples of carriers for gel filtration include dextran, agarose, etc. Examples of centrifugation conditions include 1,000 to 3,000 × g, 5 to 20 minutes, etc.

[0018] (Water-Soluble Substance) The continuous phase of the oil-in-water emulsion of the present invention is an aqueous solution of the protein material described above, and preferably contains a small amount of water. To reduce the amount of water in the aqueous solution, it is necessary to replace the water with a water-soluble substance. The water-soluble substance used in the present invention has a solubility in water of 30 (g / 100g) or more, preferably 60 (g / 100g) or more, and more preferably 100 (g / 100g) or more, and most preferably can be mixed and dissolved with water in any ratio. It also has a boiling point higher than that of water. Preferred substances are organic substances that do not contain inorganic salts or nitrogen, and examples of organic substances include polyhydric alcohols containing sugars. Polyhydric alcohol is a general term for compounds having two or more hydroxyl groups in one molecule, and there is no particular limitation on the type. Examples include glycerin, propylene glycol, sorbitol, maltitol, xylitol, erythritol, lactitol, sorbitan, xylose, arabinose, mannose, trehalose, lactose, sugar, coupling sugar, glucose, enzyme starch syrup, acid saccharified starch syrup, maltose starch syrup, maltose, isomerized sugar, fructose, reduced maltose, reduced starch starch syrup, and honey. These can be used alone or in combination of two or more. Salts include chlorides, nitrates, sulfates, phosphates, and organic acid salts of monovalent or divalent metals such as sodium, potassium, calcium, and magnesium, or ammonium, that satisfy the above-mentioned solubility. Examples include sodium chloride, ammonium sulfate, sodium dihydrogen phosphate, and sodium lactate.

[0019] (Emulsifier) ​​In the present invention, there is no need to actively incorporate any emulsifier other than the protein material described above. In particular, the inclusion of an emulsifier during the emulsification process may be undesirable in terms of quality. Here, the term "emulsifier" includes synthetic and natural emulsifiers. Specific examples include synthetic emulsifiers such as monoacylglycerol, diacylglycerol, polyglycerol fatty acid ester, sucrose fatty acid ester, sodium stearoyl lactylate, calcium stearoyl lactylate, polyoxyethylene derivatives, fatty acid salts, and modified starch, as well as lecithin derivatives obtained by chemically or enzymatically treating naturally occurring lecithins such as enzymatically hydrolyzed lecithin, hydrogenated enzymatically hydrolyzed lecithin, hydroxylecithin, phosphatidylglycerol, phosphatidic acid, and acetylated lecithin, and naturally occurring saponins such as soybean saponin and quillaja saponin. In addition, proteins that do not meet the requirements of the protein material described above, such as milk casein and lactalbumin that have not been treated according to the present invention, are also included in the emulsifiers if they have emulsifying properties.

[0020] (L-Ascorbic Acid Fatty Acid Esters) In one embodiment of the present invention, it is preferable to incorporate 0.01 to 0.2% by mass of L-ascorbic acid fatty acid esters into the oil-based material. Compared to triglyceride fatty acids, free fatty acids have significantly poorer oxidation stability, making them susceptible to oxidation during processing and storage, resulting in the problem of oils and fats becoming aged or rancid. While vitamin E, a commonly used antioxidant, is ineffective in inhibiting fatty acid oxidation, incorporating L-ascorbic acid fatty acid esters is more effective. Examples of L-ascorbic acid fatty acid esters include L-ascorbic acid palmitate and L-ascorbic acid stearate. Using L-ascorbic acid fatty acid esters in this range exhibits excellent oxidation inhibition effects. The amount of L-ascorbic acid fatty acid esters incorporated into the oil-based material is preferably 0.02 to 0.15% by mass, and even more preferably 0.03 to 0.1% by mass.

[0021] (Other Components) Various substances can be added within the range that does not affect the present invention, and examples thereof are listed below. Examples of suitable substances include sugars, nutritional components (amino acids, vitamins, minerals, etc.), alcoholic beverages, salts, fruit pulp, vegetables, vegetable juice (including concentrates), purees, extracts, sweeteners, high-intensity sweeteners (sucralose, acesulfame K, aspartame, neotame, saccharin, saccharin sodium, thaumatin, stevia, glycyrrhizin, monellin, alitame, disodium glycyrrhizinate, etc.), bittering agents (iso-alpha acid, low hops, hexahops, tetrahops, etc.), acidulants, coloring agents (safflower yellow pigment, caramel color, gardenia color, fruit juice color, vegetable color, synthetic color, etc.), food additives (dietary fiber, excipients, pH adjusters, preservatives, antioxidants (vitamin C, vitamin E, extracted tocopherol, etc.), thickeners, stabilizers, thickening agents, etc.), active ingredients or additives of pharmaceuticals, quasi-drugs, or cosmetics, etc.

[0022] (Bundling Ratio) The blending ratio is explained below. The aqueous phase and oil phase are prepared separately, but ultimately, the blending ratio is set as follows, so that the total amount is 100 parts by mass. While deviations from this blending ratio make it difficult to prepare the oil-in-water emulsion of the present invention, the preferred blending ratio allows for the production of an oil-in-water emulsion with smaller particle sizes. The oil phase is 0.5 to 35 parts by mass of the oil-based ingredient, preferably 1 to 30 parts by mass, and more preferably 2 to 15 parts by mass. The aqueous phase has the following composition. The protein ingredient accounts for 30 to 1,200% by mass, preferably 60 to 400% by mass of the oil / fat ingredient in terms of crude protein content. It is also preferable that the crude protein content meets the following criteria: 1 to 20 parts by mass, preferably 5 to 15 parts by mass, and more preferably 10 to 12 parts by mass, of a total of 100 parts by mass. The water content is 5 to 70 parts by mass, preferably 65 parts by mass or less, more preferably 35 parts by mass or less, and most preferably 20 parts by mass or less. The amount of the water-soluble substance is 1 to 80 parts by mass, preferably 10 to 70 parts by mass, and more preferably 40 to 65 parts by mass. Furthermore, the total amount of the water-soluble substance and water is preferably at least 2 times the weight of the protein material, more preferably at least 4 times, and most preferably at least 6 times. In addition to the oil-based material, protein material, and water-soluble substance, various substances can be added as long as they do not affect the present invention. On the other hand, it is preferable to avoid substances with boiling points lower than that of water, such as lower alcohols and lower hydrocarbons. Considering use in foods, etc., it is desirable to avoid their use as much as possible. Various emulsifiers that dissolve in the aqueous and oil phases can also be added. However, as with lower alcohols, one of the features of the present invention is that the oil-in-water emulsion of the present invention can be prepared without these substances, and considering use in foods, etc., it is desirable to avoid their use as much as possible.

[0023] (Preparation of Emulsion Stock Solution) The preparation method is described below, but first, the preparation of the aqueous phase will be explained. To prepare the aqueous phase, a protein material and a water-soluble substance are added to water and dissolved by stirring or other means. The temperature of the water used is not particularly limited, but warm water is preferred, with 60-80°C being appropriate. Lower temperatures increase viscosity and reduce workability, while higher temperatures may cause deterioration of the oil-soluble components added. The protein material used in this invention is characterized by its low viscosity after heating, and the aqueous phase prepared here also exhibits low viscosity despite its high crude protein concentration. Next, the preparation of the oil phase will be explained. The oil phase is the oily material described above, but typically a triglyceride to which free fatty acids and L-ascorbic acid fatty acid esters have been added is used. Heating the oil phase is also preferable depending on the fatty acids that make up the oil phase, and in most cases, it is prepared above its melting point.

[0024] (Emulsifying Apparatus) The two liquids, the aqueous phase and the oil phase, are mixed. Pre-emulsification is preferably performed at this stage. Pre-emulsification involves processing using a homomixer or similar to prepare an oil-in-water emulsion with particle sizes of approximately 10 to 100 μm. The rotation speed varies depending on the equipment; for example, in the case of a PRIMIX HOMOGENIZING MIXER MARK II Model 2.5, processing can be performed at 8,000 rpm for approximately 10 minutes. This is followed by the main emulsification. While the emulsification method is not particularly limited, emulsification devices with high shear force are preferred, including homomixers, colloid mills, high-pressure homogenizers, ultra-high-pressure homogenizers, and vacuum emulsifiers. Specifically, APV Gaulin Homogenizers (manufactured by APV), Microfluidizers (manufactured by Microfluidex), Ultimizers (manufactured by Sugino Machine), and Nanomizers (manufactured by Nanomizer) are preferred. Using these high-pressure emulsifying devices, emulsification is preferably performed at a pressure of 50 MPa or higher. For example, a microfluidizer is effective, preferably at a pressure of 100 MPa or higher, more preferably 150 MPa or higher, and for shearing at least two times, preferably four times or higher, and more preferably ten times or higher. Alternatively, a homogenization device such as an ultrasonic emulsifier may be used instead of the above-mentioned homogenization device. Examples include ultrasonic homogenizers US-600, US-1200T, RUS-1200T, and MUS-1200T (all manufactured by Nippon Seiki Seisakusho Co., Ltd.), and ultrasonic processors UIP-2000, UIP-4000, UIP-8000, and UIP-16000 (all manufactured by Hielscher). These high-power ultrasonic irradiation devices are used at frequencies of 25 kHz or lower, preferably 15 to 20 kHz.

[0025] The oil-in-water emulsion of the present invention and its raw materials are evaluated according to the following procedure.

[0026] <Crude protein content> Measured by the Kjeldahl method. Specifically, the mass of nitrogen measured by the Kjeldahl method relative to the weight of the protein material is expressed as "mass %" as the crude protein content in the dry matter. The nitrogen conversion coefficient is 6.25. Basically, it is calculated by rounding off the value to the second decimal place.

[0027] <NSI> 60 ml of water is added to 3 g of sample, and the mixture is stirred with a propeller at 37°C for 1 hour. After centrifuging at 1400 x g for 10 minutes, the supernatant (I) is collected. Next, 100 ml of water is added to the remaining precipitate, and the mixture is stirred with a propeller at 37°C for another hour. After centrifuging, the supernatant (II) is collected. Solutions (I) and (II) are combined, and water is added to the resulting mixture to make 250 ml. This mixture is filtered through filter paper (No. 5), and the nitrogen content of the filtrate is measured by the Kjeldahl method. The amount of nitrogen in the sample is also measured by the Kjeldahl method. The NSI is calculated by rounding off the value to two decimal places.

[0028] <TCA solubilization rate> An equal volume of 0.44M trichloroacetic acid (TCA) is added to a 2% by mass aqueous solution of a protein material to make a 0.22M TCA solution, and the percentage of soluble nitrogen is measured using the Kjeldahl method. This is basically calculated by rounding off the number to two decimal places.

[0029] <Viscosity (Post-Heating Viscosity)> The viscosity of the protein material is measured using a Brookfield viscometer (Toki Sangyo Co., Ltd., Type BM). A protein material aqueous solution is prepared so that the crude protein content is 20% by mass, and then filled into a measuring container. The rotor is attached, sealed, and heated in a water bath at 80°C for 30 minutes. Measurement is then performed at 25°C at an arbitrary rotation speed. The reading is read and multiplied by a conversion factor corresponding to the rotor number and rotation speed to calculate the viscosity (unit: Pa·s). This is the measurement value after 1 minute. The rotation speed is generally 60 rpm. For high-viscosity samples, change rotor number 1 to 4 and reduce the rotation speed to 6 rpm. The upper limit of viscosity for this measurement is 100,000 mPa·s. If the measurement range is exceeded using rotor number 4 and a rotation speed of 6 rpm, the post-heating viscosity is immediately determined to be 100,000 mPa·s or higher.

[0030] (Food and Drink) Examples of foods and drinks that can use the oil-in-water emulsion of the present invention include, but are not limited to, instant noodles, retort pouch foods, soups, and other instant foods; wheat flour products such as bread, pasta, noodles, and cake mixes; chocolate, biscuits, snacks, desserts, and other confectioneries; sauces, curry bases, and dressings; oily foods such as butter, mayonnaise, and margarines; dairy products such as processed milk, milk drinks, yogurt, lactic acid bacteria drinks, cheese, ice cream, and cream; frozen foods; fish paste products; ham and sausages; and canned goods. These foods and drinks can be plant-based, produced primarily from plant ingredients. The proportion of plant ingredients in the solid content of the plant-based foods and drinks is preferably 50% by mass or more, more preferably 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 100% by mass or more. The oil-in-water emulsion of the present invention can be used as an oily taste imparting agent for the foods and beverages exemplified above. The amount of the oil-in-water emulsion of the present invention in the oily taste imparting agent for foods and beverages is preferably 50% by mass or more, and can be 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 100% by mass of the solid content of the oily taste imparting agent.

[0031] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples, "%" and "parts" are by mass.

[0032] <Ingredients> The ingredients used in the examples and comparative examples are as follows: 1) Oils and fats: Palm olein: "Palm Ace N" manufactured by Fuji Oil Co., Ltd. 2) Oleic acid: "Lunac OV" manufactured by Kao Corporation (containing 78.3% oleic acid, 11.2% linoleic acid, 4.5% palmitic acid, and 1.2% lauric acid). 3) Linoleic acid: "Linoleic Acid" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. (88% or more). 4) Palmitic acid: "Palmitic Acid" manufactured by Kishida Chemical Co., Ltd. (99.5% or more). 5) Stearic acid: "Stearic Acid" manufactured by Kishida Chemical Co., Ltd. (97% or more). 6) Free fatty acids prepared by enzymatic hydrolysis of high-oleic sunflower oil: prepared by Fuji Oil Co., Ltd. Free oleic acid: 80.5%, free palmitic acid: 5.4%, free stearic acid: 2.8%, free linoleic acid: 5.7%. Total free fatty acids = 96.4% 7) Soy protein ingredient: Trade name "MIRA-MAP2.0" manufactured by Fuji Oil Co., Ltd. Crude protein content 79.3%, TCA solubilization rate 61.8%, viscosity after heating 28 mPa・s, NSI 98.1 8) Hydrophilic emulsifier A: Monooleic acid pentaglycerin ester: Trade name "Sunsoft A-171E" manufactured by Taiyo Kagaku Co., Ltd. HLB approx. 13 9) Hydrophilic emulsifier B: Sucrose stearate ester: Trade name "Ryoto Sugar Ester S-1670" manufactured by Mitsubishi Chemical Corporation HLB approx. 16 10) Lecithin: Trade name "SLP-White" manufactured by Tsuji Oil Mills 11) Polyglycerin condensed ricinoleate ester: Trade name "SY Glystar CRS-75" manufactured by Sakamoto Pharmaceutical Industry Co., Ltd. 12) Ascorbyl palmitate ester: Trade name "L- "Ascorbic Acid Palmitate" manufactured by DSM. 13) Bouillon (Western-style soup stock): "Maggi Bouillon No Additives" manufactured by Nestle Japan. Salt equivalent: 52.5g per 100g. Ingredients: Salt (manufactured in Japan), dextrin, yeast extract, sugar, onion, spices.

[0033] (Emulsion particle size measurement) Samples were prepared by diluting oil-in-water emulsions or aqueous foods containing oil-in-water emulsions with ion-exchanged water to a concentration of 0.03% oily material. The particle size of oil droplets in water was measured as the calculated Z-average (nm) using a Malvern Zetasizer nano-ZS (Model ZEN3600). Measurements were performed three times at 25°C using a 2g sample in a glass cell with a 1cm light path, and the average value was used as the average emulsion particle size. The measurement conditions were as follows: RI (Material) 1.47, Absorption (Material) 0, Temperature (Dispersant) 25°C, Viscosity (Dispersant) 0.887 (cp), RI (Dispersant) 1.33, Equilobration time 60 seconds, Number of runs 10, Run duration 10, Number of measurements 1, and Dela between measurements 0 seconds.

[0034] (Examples 1 to 10, Comparative Examples 1 to 14) (Preparation of oil-in-water emulsions) Oil-in-water emulsions were prepared as follows according to Tables 1 to 3. That is: a) Preparation of oil phase: The materials corresponding to the oil phases in the formulations shown in Tables 1 to 3 were mixed, heated to 80°C, and mixed for 5 minutes using a homomixer (HOMOGENIZING MIXER MARK II Model 2.5, manufactured by PRIMIX) to prepare the oil phase. b) Preparation of water phase: The materials corresponding to the water phases in the formulations shown in Tables 1 to 3 were dissolved in water at 80°C and mixed for 5 minutes using a homomixer to prepare the water phase. c) The oil phase prepared in step a) was added to the water phase in step b), and pre-emulsified using a homomixer at 80°C for 5 minutes to an emulsion particle size of 10 to 60 μm. d) The mixture from step c) was treated with a high-pressure homogenizer (Microfluidizer Microfluidics) at the pressures and for the number of treatments shown in Tables 1 to 3 to prepare oil-in-water emulsions. The oil-in-water emulsions of Comparative Examples 2 to 6, 8, 10 to 12, and 14 had emulsion particle sizes exceeding 100 nm.

[0035] (Evaluation of oil-in-water emulsion) The obtained oil-in-water emulsion was diluted with water to make a 1% solution, and evaluated in terms of oily taste and bitterness.

[0036] (Evaluation criteria for oily taste) Six experienced panelists evaluated the reference sample (rating = 1 point) of the additive-free group, and the average of the evaluation scores was used to evaluate the sample. The higher the score, the stronger the oily taste felt and the more preferable it was. A score of 3 or more was considered to be acceptable. 5 points: The oily taste was felt to be very strong compared to the reference sample. 4 points: The oily taste was felt to be somewhat strong compared to the reference sample. 3 points: The oily taste was felt to be strong compared to the reference sample. 2 points: The oily taste was felt compared to the reference sample, but was insufficient. 1 point: The same as the reference sample, and no oily taste was felt.

[0037] (Bitterness evaluation criteria) Six experienced panelists evaluated the reference sample (rating = 1 point) of the additive-free group, and the average of the evaluation scores was used for evaluation. The higher the score, the more suppressed the bitterness and the more preferable it is. A score of 3 or more was considered to be acceptable. 5 points: A very slight bitterness is felt compared to the reference sample. 4 points: A weak bitterness is felt compared to the reference sample. 3 points: A bitterness is felt compared to the reference sample, but at a level that is not problematic in practical use. 2 points: A strong bitterness is felt compared to the reference sample. 1 point: A very strong bitterness is felt compared to the reference sample.

[0038] (Overall evaluation) A product was deemed to have passed if both the oily taste and bitterness scores were 3 points or higher. Furthermore, among those that passed, a product with a total score of 7.5 points or higher was deemed to be more preferable. A product with a total score of 8.0 points or higher was deemed to be even more preferable, and a product with a total score of 8.5 points or higher was deemed to be the most preferable.

[0039] (Table 1)

[0040] (Table 2)

[0041] (Table 3)

[0042] As shown in Examples 1 to 10 in Table 1, by incorporating a specific amount of oleic acid into an oil-based ingredient and refining it to an emulsion particle size of 100 nm or less, it is possible to enhance the oily taste and suppress the bitterness. On the other hand, as shown in Comparative Examples 1 to 6, there was no effect when the oil-based ingredient did not contain fatty acids or when the particle size of the oil-in-water emulsion exceeded 100 nm. Furthermore, as shown in Comparative Examples 7 to 12, when the specific soy protein ingredient of the present invention was not used, the oily taste was weak and ineffective. As shown in Comparative Examples 13 and 14, even when a synthetic emulsifier and soy protein ingredient were included, the effect was low without fatty acids.

[0043] (Examples 11-12) Effect of Oxidative Degradation Due to Light Irradiation Dilutions of the oil-in-water emulsions of Examples 1 and 6 were filled into transparent glass containers, and the effect of oxidative degradation was observed immediately after dilution and after 48 hours at 25°C under an LED light source of 4000 lux. The oily taste and bitterness were evaluated in the same manner as in Example 1, and the evaluation method for oxidative odor is shown below. The results are shown in Table 4.

[0044] (Evaluation criteria for oxidized odor) Six experienced panelists evaluated the unadded group and the reference example stored in a dark place (rating score = 5 points), and the average of the rating scores was used for evaluation. The higher the score, the more suppressed the oxidized odor and the more preferable the product. A score of 3 or more was judged to be acceptable. 5 points: Almost no oxidized odor of lipids is detected compared to the reference example. 4 points: A slight oxidized odor of lipids is detected compared to the reference example. 3 points: A oxidized odor of lipids is detected compared to the reference example, but at a level that is not problematic in practical use. 2 points: A stronger oxidized odor of lipids is detected compared to the reference example. 1 point: A very strong oxidized odor of lipids is detected compared to the reference example.

[0045] (Table 4)

[0046] As shown in Table 4, even when the oil-in-water emulsions of Examples 1 and 6 were irradiated with light, the oxidized odor was at an innocuous level, and it was confirmed that the stability was also excellent.

[0047] (Examples 13 to 15) Oil-in-water emulsions were prepared based on the formulations in Table 5 and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 5.

[0048] (Table 5)

[0049] As shown in Table 5, even when fatty acids other than oleic acid were used, the evaluation of oily taste and bitterness was favorable.

[0050] (Examples 16 and 17) Effect of oxidative deterioration due to light irradiation The oil-in-water emulsions of Examples 14 and 15 were examined for the effect of oxidative deterioration in the same manner as in Example 11. The results are shown in Table 6.

[0051] (Table 6)

[0052] (Examples 18 to 20) Oil-in-water emulsions were prepared and evaluated in the same manner as in Example 1 based on the formulations in Table 7. The evaluation results are shown in Table 6. As shown in Table 7, when vitamin E or ascorbyl palmitate was added, the evaluation of oily taste and bitter taste was favorable.

[0053] (Table 7)

[0054] (Examples 21 to 23) Effect of ascorbic acid fatty acid esters on oxidative deterioration due to light irradiation The oil-in-water emulsions of Examples 18 to 20 were examined for the effect of oxidative deterioration in the same manner as in Example 11. The results are shown in Table 8.

[0055] (Table 8)

[0056] As can be seen from Examples 21 to 23, by incorporating an L-ascorbic acid fatty acid ester in advance into the oil phase of an oil-in-water emulsion containing oleic acid or linoleic acid, the quality of the nanoemulsion composition as an oily taste imparting agent with improved oxidation stability can be improved.

[0057] Example 24: Effect of free fatty acids prepared by enzymatic hydrolysis of high oleic sunflower oil. 100 parts high oleic sunflower oil (Hiol 75B, Fuji Oil Co., Ltd.), 100 parts water, 0.1 parts Lipase GS "Amano" 250G (a purified lipase derived from Penicillium camemberti), and 2 parts Lipase AY "Amano" 30SD (a purified lipase derived from Candida sp.) were mixed using a propeller mixer under a nitrogen atmosphere and subjected to an enzymatic reaction at 40°C for 30 hours. The mixture was centrifuged (2000 x g, 10 minutes) to recover the oil phase, which was then heated at 110°C for 10 minutes under a reduced pressure of 10 Torr for dehydration and enzyme inactivation to obtain free fatty acids prepared by enzymatic hydrolysis of high oleic sunflower oil. Using this free fatty acid, an oil-in-water emulsion was prepared according to the formulation in Table 9 in the same manner as in Example 1 and evaluated in the same manner as in Example 1. The results are shown in Table 9.

[0058] (Table 9)

[0059] The free fatty acids prepared by enzymatic hydrolysis of high oleic sunflower oil also showed good results in terms of oily taste and bitterness.

[0060] (Examples 25-29, Comparative Examples 15-20) (Application to Foods) Using the oil-in-water emulsions of each Example and Comparative Example, bouillon and the oil-in-water emulsions were added to warm water at 85°C according to the formulations shown in Table 8, and the mixture was stirred with a spatula to dissolve uniformly, thereby preparing consommé soup as an aqueous food containing an oil-in-water emulsion. Subsequently, the oily taste and bitterness were evaluated in the same manner. The results are shown in Table 10.

[0061] (Table 10)

[0062] As can be seen from the examples and comparative examples in Table 10, even in foods, by blending a specific amount of free fatty acids into an oily ingredient and micronizing it to an emulsified particle size of 100 nm or less, it is possible to produce a stronger oily taste and suppress the bitterness.

[0063] The present invention makes it possible to impart an oily taste to a wide range of aqueous foods, thereby contributing to improved taste and health promotion.

Claims

1. An oil-in-water emulsion containing an oily material, a water-soluble substance, water, and a protein material, having an emulsion particle size of 100 nm or less, and satisfying the following requirements (A) and (B): (A) the oily material contains at least free fatty acids, (B) the protein material has a viscosity of 10,000 mPa s or less when measured at 25°C after heating an aqueous solution containing 20% ​​crude protein by weight at 80°C for 30 minutes, and has a 0.22M TCA solubilization rate of 30% to 95%.

2. The oil-in-water emulsion according to claim 1, wherein the free fatty acid is one or more selected from the group consisting of oleic acid, linoleic acid, palmitic acid and stearic acid.

3. The oil-in-water emulsion according to claim 1, comprising 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material, and wherein (A) contains 1 to 99% by mass of free fatty acids in the oily material.

4. The oil-in-water emulsion according to claim 2, comprising 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material, and wherein (A) contains 1 to 99% by mass of free fatty acids in the oily material.

5. The oil-in-water emulsion according to claim 3, comprising 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material, and further comprising (A) 1 to 99% by mass of free fatty acids and 1 to 99% by mass of fats and oils.

6. The oil-in-water emulsion according to claim 4, comprising 0.5 to 35% by mass of an oily material, 1 to 80% by mass of a water-soluble substance, 5 to 70% by mass of water, and 30 to 1,200% by mass of a protein material in terms of crude protein content of the oily material, and further comprising (A) 1 to 99% by mass of free fatty acids and 1 to 99% by mass of fats and oils.

7. The oil-in-water emulsion according to claim 1, wherein the NSI of the protein material is 80 or more.

8. The oil-in-water emulsion according to claim 2, wherein the protein ingredient has an NSI of 80 or more.

9. The oil-in-water emulsion according to claim 3, wherein the protein ingredient has an NSI of 80 or more.

10. The oil-in-water emulsion according to claim 4, wherein the protein ingredient has an NSI of 80 or more.

11. The oil-in-water emulsion according to claim 5, wherein the protein ingredient has an NSI of 80 or more.

12. The oil-in-water emulsion according to claim 6, wherein the protein ingredient has an NSI of 80 or more.

13. The oil-in-water emulsion according to claim 1, having a water content of 65% by mass or less.

14. The oil-in-water emulsion according to claim 2, having a water content of 65% by mass or less.

15. The oil-in-water emulsion according to claim 1, further comprising an L-ascorbic acid fatty acid ester in the oily material.

16. The oil-in-water emulsion according to claim 2, further comprising an L-ascorbic acid fatty acid ester in the oily material.

17. The oil-in-water emulsion of claim 1 which is vegetable-based.

18. The oil-in-water emulsion of claim 2, which is vegetable-based.

19. A method for producing an oil-in-water emulsion with an emulsion particle size of 100 nm or less, comprising mixing 0.5 to 35 mass% of an oily material containing free fatty acids with a solution of 30 to 1,200 mass% of an oily material (crude protein amount) of protein material, 1 to 80 mass% of a water-soluble substance, and 5 to 70 mass% of water, and applying shear force.

20. A method for producing an oil-in-water emulsion according to claim 19, wherein the protein material has a viscosity of 10,000 mPa·s or less when measured at 25°C after heating an aqueous solution containing 20% ​​by mass of crude protein at 80°C for 30 minutes, a 0.22M TCA solubilization rate of 30 to 95%, and an NSI of 80 or more.

21. A food or drink comprising the oil-in-water emulsion according to claim 1.

22. A food or drink comprising the oil-in-water emulsion according to claim 2.

23. An agent for imparting an oily taste to food or beverage, comprising the oil-in-water emulsion according to claim 1.

24. An agent for imparting an oily taste to food or beverage, comprising the oil-in-water emulsion according to claim 2.

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