Oil-in-water emulsion

Abstract

The present invention provides an oil-in-water emulsion which has emulsion stability whilst also being free of one or more selected from the group consisting of emulsifiers, sodium caseinate, salts and acidulants, the oil-in-water emulsion being suppressed in aggregation even in an acidic environment.　It has been found that an oil-in-water emulsion being substantially free of one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants, in which the oil-in-water emulsion has emulsion stability and suppressed aggregation even in an acidic environment, can be obtained by including a milk-derived phospholipid-containing dairy product and casein protein in the oil-in-water emulsion.

Description

Oil-in-water emulsion

[0001] Related Application This application claims the benefit of priority of Japanese Patent Application No. 2025-019035 filed on February 7, 2025. The priority-based application is incorporated herein by reference in its entirety.

[0002] The present invention relates to an oil-in-water emulsion.

[0003] Reflecting recent consumer trends, food and beverages that do not use food additives such as emulsifiers have been actively developed. For example, Patent Document 1 discloses an oil-in-water emulsion using carrageenan containing i-carrageenan that does not mainly contain calcium. Patent Document 2 discloses an oil-in-water emulsion containing milk protein that has been ultra-high temperature instantaneously sterilized and contains sugar alcohol. Patent Document 3 also discloses an oil-in-water emulsified oil and fat composition containing emulsifying starch and wheat protein hydrolyzate.

[0004] JP-A-2001-128625 JP-A-10-304821 JP-A-2009-232751

[0005] Although Patent Documents 1 and 2 do not use synthetic emulsifiers, they are inventions limited to some emulsifiers. Further, in Patent Document 3, even when containing emulsifying starch and wheat protein hydrolyzate, it is shown that some precipitation occurs, and it has to be said that the acid resistance is still insufficient. It is not easy to distribute an oil-in-water emulsion in which some precipitation occurs. In particular, as also discussed in Patent Document 3, when used in combination with acidic ingredients such as fruit juice or wine, such as white sauce, the pH may decrease, resulting in an unstable emulsified state. From the above, it can be said that it is very difficult to produce an oil-in-water emulsion with good emulsion stability that does not use emulsifiers, sodium caseinate, salts, acidulants, etc. when used in an oil-in-water emulsion. Therefore, an object of the present invention is to provide an oil-in-water emulsion that has emulsion stability without containing at least one selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants and in which aggregation is suppressed even in an acidic environment.

[0006] In order to solve the above problems, the inventors conducted extensive research and found that by incorporating a dairy product containing milk-derived phospholipids and casein protein into an oil-in-water emulsion, an oil-in-water emulsion with emulsification stability and suppressed aggregation even in an acidic environment can be obtained.

[0007] In other words, the present invention relates to: [1] an oil-in-water emulsion that substantially does not contain one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants, and comprises a milk-derived phospholipid-containing dairy product and casein protein; [2] the oil-in-water emulsion according to [1], wherein the mass ratio of phospholipid content to protein content in the oil-in-water emulsion (phospholipid content / protein content) is 0.01 to 0.5; [3] the oil-in-water emulsion according to [1], wherein the mass ratio of casein protein to protein content in the oil-in-water emulsion is 0.25 to 0.95; [4] the oil-in-water emulsion according to [1], wherein the pH of the oil-in-water emulsion is 6 to 8; [5] the oil-in-water emulsion according to [2], wherein the mass ratio of casein protein to protein content in the oil-in-water emulsion is 0.25 to 0.95. [6] The oil-in-water emulsion according to [2], wherein the pH of the oil-in-water emulsion is 6 to 8; [7] The oil-in-water emulsion according to [3], wherein the pH of the oil-in-water emulsion is 6 to 8; [8] The oil-in-water emulsion according to [5], wherein the pH of the oil-in-water emulsion is 6 to 8; [9] A processed food containing the oil-in-water emulsion according to [1] to [8];

[10] A method for producing an oil-in-water emulsion that substantially does not contain one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants, the method for producing an oil-in-water emulsion comprising the step of emulsifying a dairy product containing milk-derived phospholipids and a raw material containing casein protein.

[0008] According to the present invention, it is possible to provide an oil-in-water emulsion with good physical properties without using one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants.

[0009] The present invention will be described in detail below.

[0010] ■Oil-in-Water Emulsion The oil-in-water emulsion of the present invention is characterized by not containing one or more substances selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants. Specifically, examples of emulsifiers include glycerin fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, sucrose fatty acid esters, lecithin, etc. for emulsifiers; sodium carbonate, sodium hydroxide, sodium lactate, phosphates, metaphosphates, polyphosphates, pyrophosphates, citric acid, baking soda, etc. for salts; and citric acid, L-tartaric acid, lactic acid, etc. for acidulants. Sodium caseinate is designated as a food additive. In Japan, emulsifiers, sodium caseinate, salts, and acidulants as used in this application refer to those approved for use by the Consumer Affairs Agency. Furthermore, in this invention, "substantially free of one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants" means that one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants are present in the oil-in-water emulsion at a concentration of 0.09% by mass or less. More preferably, 0.06% by mass or less, even more preferably 0.03% by mass or less, even more preferably 0.01% by mass or less, and most preferably 0% by mass. This invention makes it possible to obtain an oil-in-water emulsion with good physical properties without using one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants. If one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants are included, their total amount must fall within the above numerical range.

[0011] ■ Dairy Products Containing Milk-Derived Phospholipids The oil-in-water emulsion of the present invention includes dairy products containing milk-derived phospholipids. These milk-derived phospholipid-containing dairy products are dairy products containing 2% by mass or more of milk-derived phospholipids. For example, "Beta Serum Powder" and "Phospholipid Concentrate" manufactured by Tatsua Japan Co., Ltd. can be used as milk-derived phospholipid-containing dairy products. By incorporating milk-derived phospholipid-containing dairy products into the oil-in-water emulsion, it is possible to obtain an oil-in-water emulsion with good emulsification stability and suppressed aggregation in an acidic environment. On the other hand, oil-in-water emulsions directly containing lecithin derived from plants or animals are not within the scope of the present invention.

[0012] The mass ratio of phospholipid content to protein content (phospholipid content / protein content) in the oil-in-water emulsion of the present invention is preferably 0.01 to 0.5. More preferably 0.01 to 0.4, even more preferably 0.02 to 0.35, and even more preferably 0.03 to 0.3. Within this range, an oil-in-water emulsion with good emulsification stability and suppressed aggregation in an acidic environment can be obtained.

[0013] The phospholipid content in the oil-in-water emulsion of the present invention is preferably 0.01 to 0.5% by mass. More preferably 0.01 to 0.4% by mass, even more preferably 0.01 to 0.35% by mass, and even more preferably 0.02 to 0.35% by mass. Within this range, an oil-in-water emulsion with good emulsion stability and suppressed aggregation in an acidic environment can be obtained.

[0014] ■Casein Protein The oil-in-water emulsion of the present invention contains casein protein. This casein protein is a type of protein found in milk. Specifically, examples include casein protein, calcium caseinate, magnesium caseinate, potassium caseinate, etc. More preferably, casein protein, magnesium caseinate, and potassium caseinate. Note that sodium caseinate is not within the scope of the present invention. By including casein protein in the oil-in-water emulsion, it is possible to obtain an oil-in-water emulsion with good emulsion stability and suppressed aggregation in an acidic environment.

[0015] The amount of casein protein in the oil-in-water emulsion of the present invention is preferably 0.25 to 0.95 as the mass ratio of casein protein to the total protein content in the oil-in-water emulsion. More preferably 0.28 to 0.90, even more preferably 0.30 to 0.85, and even more preferably 0.35 to 0.80. In this invention, the amount of casein protein refers to the amount of casein contained in the casein protein. Within this range, an oil-in-water emulsion with good emulsion stability and suppressed aggregation in an acidic environment can be obtained.

[0016] The oil-in-water emulsion of the present invention preferably has a pH of 6 to 8. More preferably, it is 6.2 to 7.8, and even more preferably 6.3 to 7.5. Within this range, an oil-in-water emulsion with good emulsification stability and suppressed aggregation in an acidic environment can be obtained.

[0017] ■Whey Protein The oil-in-water emulsion of the present invention may or may not contain whey protein in addition to milk-derived phospholipid-containing dairy products and casein protein. More preferably, the oil-in-water emulsion contains whey protein. Whey protein is also a type of protein contained in milk. Specifically, whey protein concentrate (WPC), whey protein isolate (WPI), whey powder, etc., can be exemplified. When whey protein is contained in the oil-in-water emulsion, it is preferable that the amount of whey protein in the oil-in-water emulsion is 0.05 to 5% by mass. More preferably, it is 0.1 to 4.5% by mass, even more preferably 0.2 to 4.3% by mass, and even more preferably 0.3 to 4% by mass. Being within this range allows for the production of an oil-in-water emulsion with good emulsion stability and suppressed aggregation in an acidic environment.

[0018] ■Oils and Fats The oils and fats constituting the oil-in-water emulsion of the present invention are not particularly limited as long as they are oils and fats commonly used in food. Specifically, examples include vegetable oils such as palm oil, rapeseed oil, high erucic acid rapeseed oil, sunflower oil, high oleic sunflower oil, soybean oil, rice oil, corn oil, cottonseed oil, peanut oil, safflower oil, olive oil, sesame oil, flaxseed oil, palm kernel oil, coconut oil, medium-chain triglyceride (MCT), shea butter, sal fat, and cocoa butter; animal oils such as milk fat, beef tallow, lard, fish oil, and whale oil; algae oil; oils and fats derived from microbial fermentation; processed oils and fats obtained by fractionation, hydrogenation, transesterification, etc. of these; and mixed oils and fats. Of course, oils and fats mixed from two or more of these can also be used. It is preferable to use super-hydrogenated palm kernel oil to obtain better physical properties. Furthermore, it is preferable to use palm oil or fractionated palm oil in order to ensure a more stable supply. The oil content in the oil-in-water emulsion is preferably 1 to 50% by mass. More preferably 3 to 48% by mass, and even more preferably 5 to 46% by mass. Within this range, an oil-in-water emulsion with good emulsion stability and suppressed aggregation in an acidic environment can be obtained.

[0019] As described above, the oil-in-water emulsion of the present invention is a neutral oil-in-water emulsion, and therefore preferably is substantially acid-free. The acid referred to here is a general organic acid and an inorganic acid. Specifically, examples of organic acids include acetic acid, lactic acid, citric acid, gluconic acid, phytic acid, sorbic acid, adipic acid, succinic acid, tartaric acid, fumaric acid, malic acid, ascorbic acid, etc., and examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc. In the present invention, "substantially acid-free" means more preferably 0.1% by mass or less, even more preferably 0.05% by mass or less, and even more preferably 0% by mass.

[0020] ■Method for Producing Oil-in-Water Emulsification The method for producing oil-in-water emulsion according to the present invention will now be described. Oil-in-water emulsion according to the present invention can be obtained by emulsifying an oil phase, which is a mixture of fats and oils and optionally oil-soluble components, and an aqueous phase, which is a mixture of dairy products containing phospholipids derived from milk, casein protein, other proteins, water, and optionally water-soluble components, into an oil-in-water type. For example, dairy products containing phospholipids derived from milk, casein protein, and optionally whey protein are added to water or warm water and stirred to prepare an aqueous phase in which the substances are dissolved or dispersed. Then, the oil phase prepared in advance is added to perform preliminary emulsification to obtain a preliminary emulsion. The preliminary emulsion is homogenized at a pressure in the range of 0 to 100 MPa, preferably using a homogenization device such as a bubble homogenizer, homomixer, or colloid mill. Then, if necessary, heat sterilization or heat disinfection treatment such as UHT / HTST / low temperature pasteurization, batch type, retort, or microwave heating may be performed using a direct heating method such as injection type or infusion type, or an indirect heating method such as plate type, tubular type, or scraping type. Furthermore, this may be further homogenized at a pressure of 0 to 100 MPa, preferably using a homogenizing device such as a valve-type homogenizer, homomixer, or colloid mill. If necessary, cooling operations such as rapid cooling or slow cooling may be performed. The oil-in-water emulsion of the present invention may also be stored refrigerated or frozen, if necessary. Of course, it can also be manufactured by methods known to those skilled in the art other than those described above.

[0021] The oil-in-water emulsion of the present invention may contain auxiliary ingredients as needed, provided it does not contain one or more ingredients selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants. Examples include dairy ingredients (raw milk, skimmed condensed milk, skimmed milk powder, fresh cream, butter, cheese, etc.), carbohydrate sweeteners (sugar, corn syrup, fructose, glucose, sugar alcohols, etc.), starch (starch derived from grains such as rice, wheat, etc., starch derived from corn, starch derived from potatoes, tapioca, etc.), salt, eggs, flavoring ingredients (coffee, cocoa, tea, chocolate ingredients, fruit juice, fruit pulp, nuts, honey, maple syrup, alcohol, etc.), and various nutrients (protein, dietary fiber such as indigestible dextrin, etc.). Of course, food additives other than emulsifiers, sodium caseinate, salts, and acidulants can also be used.

[0022] The oil-in-water emulsion of the present invention not only exhibits emulsification stability in a neutral environment but also has the effect of suppressing aggregation in an acidic environment. Therefore, even when materials with an acidic pH, such as fruits, vegetables, or seasonings, are included in the oil-in-water emulsion, aggregation does not occur, and good physical properties can be maintained. Furthermore, when manufacturing processed foods containing the oil-in-water emulsion, even when materials with an acidic pH are included as raw materials for the processed food, aggregation does not occur, and good physical properties can be maintained.

[0023] The oil-in-water emulsion of the present invention can be used as a raw material for processed foods, but there are no particular restrictions on the processed foods that can be used. Examples include sauces such as curry, stew, and pasta sauce; bases for gratin and hot pot; processed cooked foods such as soups; prepared foods such as sausages and hamburgers; beverages such as café au lait, milk tea, dairy beverages, and soft drinks; and dessert foods such as pudding, almond tofu, and various jellies. Processed cooked foods are more preferable.

[0024] (Examples) Embodiments of the invention will be described in more detail below with reference to examples. Unless otherwise specified, parts and percentages are based on mass.

[0025] ■Production of Oil-in-Water Emulsions for Comparative Examples 1-4 and Examples 1-10 Oil-in-Water emulsions for Comparative Examples 1-4 and Examples 1-10 were produced according to the formulations in Table 1. The production method was as follows: ■Production Method for Oil-in-Water Emulsions 1. Milk-derived phospholipid-containing dairy products and / or casein protein were added to warm water and mixed in a mixer to obtain the aqueous phase. In Comparative Example 2 and Examples 4-9, whey protein was also added to the aqueous phase. 2. Oil and fat were heated, dissolved, and mixed to obtain the oil phase. 3. The aqueous phase was added to the oil phase and mixed, and pre-emulsification was performed in a pre-emulsification tank at 60°C for 20 minutes to obtain a pre-emulsified liquid. 4. The pre-emulsified liquid was preheated to 70-80°C in a plate-type heat exchanger and heated to 140-150°C in an ultra-high temperature sterilizer (manufactured by Iwai Kiki Kogyo Co., Ltd., direct steam blowing method). 5.4. The emulsion obtained was sterilized in a holding tube at 140-150°C for 3-12 seconds. The emulsion obtained in 6.5 was cooled by steam cooling until the product temperature reached 70-80°C and homogenized. The emulsion obtained in 7.6 was cooled in a plate heat exchanger until the product temperature reached 10°C or below to obtain each oil-in-water emulsion.

[0026] The raw materials used in the study were as follows:・Milk-derived phospholipid-containing dairy product 1: "Beta Serum Powder" manufactured by Tatua Japan Co., Ltd. (phospholipid 5.6% by mass, protein content 29.8% by mass, of which casein protein 23.8% by mass, whey protein 6.0% by mass) ・Milk-derived phospholipid-containing dairy product 2: "Phospholipid concentrate" manufactured by Tatua Japan Co., Ltd. (phospholipid 13.0% by mass, protein content 51.3% by mass, of which casein protein 41.0% by mass, whey protein 10.3% by mass) ・Casein protein: "TATUA500" manufactured by Tatua Japan Co., Ltd. (phospholipid 0.1% by mass or less, protein content 91.2% by mass, of which casein protein 91.2% by mass, whey protein 0% by mass) ・Whey protein 1: "GermanProt" manufactured by Sachsenmilch Leppersodort GmbH WPI (Phospholipid 0.1% by mass or less, protein content 89.0% by mass, casein protein of protein content 0% by mass, whey protein 89.0% by mass) ・Whey protein 2: "GermanProt WPC70 PhospHolipid enricHed" manufactured by SACHSENMILCH Leppersodort GmbH (Phospholipid 0.1% by mass or less, protein content 69.5% by mass, casein protein of protein content 0% by mass, whey protein 69.5% by mass) ・Whey protein 3: Saputo Daily Pty Ltd.・WPC 80% (Phospholipid 0.1% by mass or less, protein content 76.5% by mass, casein protein of protein content 0% by mass, whey protein 76.5% by mass) ・Whey powder: Snow Brand Megmilk Co., Ltd. "Whey powder" (Phospholipid 0.1% by mass or less, protein content 11.8% by mass, casein protein of protein content 0% by mass, whey protein 11.8% by mass) ・Palm oil with medium melting point: Fuji Oil Co., Ltd. ・Hyperhydrogenated palm kernel oil: Fuji Oil Co., Ltd.

[0027] ■Evaluation Method The oil-in-water emulsions of Comparative Examples 1-4 and Examples 1-10 were evaluated based on two criteria: emulsion stability in a neutral environment and aggregation in an acidic environment, as shown below. Emulsifications that passed all evaluation criteria were considered to have passed the overall evaluation.

[0028] ■Emulsification Stability in a Neutral Environment <Method of Sludge Test at 5°C or 20°C> Emulsification stability in a neutral environment was evaluated based on the presence or absence of sludge at 5°C and 20°C, and the properties of the oil-in-water emulsion. First, 50g of cream was placed in a 100mL beaker and kept warm at 20°C for 2 hours or at 5°C for 2 hours, respectively. After that, it was vibrated using a horizontal shaker for 20 minutes, and the presence or absence of sludge in the cream was visually checked. If the liquid state was maintained and no sludge occurred for 20 minutes or more, it was scored 4 points; if the liquid state was maintained, it was scored 3 points; if slight sludge occurred but within an acceptable range, it was scored 2 points; and if solidification or sludge occurred, it was scored 1 point. A score of 2 points or more was considered a pass. Note that "sludge" refers to a significant increase in viscosity or solidification that occurs due to rising temperature or vibration during transport. If the liquid state was maintained, it was considered to have good emulsion stability and was considered a pass.

[0029] <Viscosity Measurement> The properties of the oil-in-water emulsion were also confirmed by measuring its viscosity. The measurement was performed at 5°C using a BM-type viscometer. Samples with a viscosity of 2000 cP or less were deemed acceptable, while those that could not be measured due to thickening or poor emulsification were deemed unacceptable.

[0030] ■Agglutination in an Acidic Environment The evaluation of agglutination in an acidic environment was as follows: Each oil-in-water emulsion was diluted with water to a concentration of 25% by mass to obtain a dilution. This dilution was adjusted to a pH of 4.5 with a 10% by mass citric acid aqueous solution. The pH-adjusted solution was scooped with a spatula and visually checked for the presence or absence of agglutination. The presence or absence of agglutination was judged as follows, and a score of 2 or more was considered a pass, indicating no agglutination in an acidic environment. 4 points: The pH-adjusted solution did not separate, and no agglutination was observed. 3 points: The pH-adjusted solution did not separate, was not viscous, and only a few fine agglutinations were observed. 2 points: The pH-adjusted solution did not separate, and overall viscousness or fine agglutinations were observed. 1 point: The pH-adjusted solution separated, and agglutinations were observed.

[0031] ■Table 1

[0032] In oil-in-water emulsions containing milk-derived phospholipids and casein protein in specific ratios, emulsification stability in a neutral environment and aggregation in an acidic environment were good (Examples 1-10). On the other hand, in oil-in-water emulsions that did not contain milk-derived phospholipids and casein protein in specific ratios, emulsification stability in a neutral environment and aggregation in an acidic environment were poor (Comparative Examples 1-4).

[0033] The present invention provides an oil-in-water emulsion that has emulsification stability without containing one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants, and in which aggregation is suppressed even in an acidic environment.

Claims

1. An oil-in-water emulsion that substantially does not contain one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants, and contains a milk-derived phospholipid-containing dairy product and casein protein.

2. The oil-in-water emulsion according to claim 1, wherein the mass ratio of phospholipid content to protein content in the oil-in-water emulsion (phospholipid content / protein content) is 0.01 to 0.

5.

3. The oil-in-water emulsion according to claim 1, wherein the mass ratio of casein protein to the total protein content in the oil-in-water emulsion is 0.25 to 0.

95.

4. The oil-in-water emulsion according to claim 1, wherein the pH of the oil-in-water emulsion is 6 to 8.

5. The oil-in-water emulsion according to claim 2, wherein the mass ratio of casein protein to the total protein content in the oil-in-water emulsion is 0.25 to 0.

95.

6. The oil-in-water emulsion according to claim 2, wherein the pH of the oil-in-water emulsion is 6 to 8.

7. The oil-in-water emulsion according to claim 3, wherein the pH of the oil-in-water emulsion is 6 to 8.

8. The oil-in-water emulsion according to claim 5, wherein the pH of the oil-in-water emulsion is 6 to 8.

9. A processed food containing the oil-in-water emulsion described in claims 1 to 8.

10. A method for producing an oil-in-water emulsion that substantially does not contain one or more selected from the group consisting of emulsifiers, sodium caseinate, salts, and acidulants, comprising the step of emulsifying a dairy product containing milk-derived phospholipids and a raw material containing casein protein.

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