JP2022053686A - Method for producing oil-in-water emulsion, method for producing foam-containing oil-in-water emulsion, method for producing frozen foam-containing oil-in-water emulsion, method for producing acidic oil-in-water emulsion, method for producing foam-containing acidic oil-in-water emulsion, and oil-in-water emulsion - Google Patents

Abstract

To provide a method for producing oil-in-water emulsion that can be foamed when an acidic material is added thereto, and retains its shape well after foaming.SOLUTION: A method for producing oil-in-water emulsion includes the steps of: preparing a homogenized, first oil-in-water emulsion containing oil and fat and water with protein content of less than 1.4 mass%; and mixing the homogenized, first oil-in-water emulsion with protein-containing raw material to prepare a second oil-in-water emulsion.SELECTED DRAWING: None

Description

The present invention relates to a method for producing an oil-in-water emulsion, a method for producing an oil-in-water emulsion containing bubbles, a method for producing an oil-in-water emulsion containing frozen bubbles, a method for producing an oil-in-water emulsion in acid water, and an acidic water containing bubbles. The present invention relates to a method for producing an oil-type emulsion and an oil-in-water emulsion.

Creams are used for a variety of purposes. For example, whipped cream, which is made by foaming edible cream such as fresh cream or compound cream, is used for decorating confectionery such as cakes and fruit meat, and is floated on beverages such as Winna coffee.
As the cream, for example, an oil-in-water emulsion containing fat, water and protein is used. In general, such an oil-in-water emulsion is prepared by mixing an aqueous phase portion containing water and protein and an oil phase portion containing an oil-soluble component such as oil and fat to pre-emulsify, homogenize, sterilize and cool, and more preferably. Is subsequently manufactured by aging.
It has been proposed to add, mix, and sterilize skim milk concentrate after aging in order to impart a flavor such as milkiness or richness to the cream (Patent Document 1).

On the other hand, in the whipped cream market, there is a need to obtain whipped cream with a refreshing taste with acidity by adding low pH acidic foods such as fruit juice and acidic materials such as acidic compounds. ing.
However, the oil-in-water emulsion generally has low acid resistance, and when the pH is lowered, the proteins in the oil-in-water emulsion aggregate and the oil-in-water emulsion thickens or solidifies. Therefore, it is difficult to add an acidic material to the oil-in-water emulsion to cause foaming. Further, even if an acidic material is mixed after foaming the oil-in-water emulsion, the protein aggregates and the texture of the whipped cream deteriorates. Therefore, there is a demand for a technique for imparting acid resistance to an oil-in-water emulsion, particularly a technique for imparting a property (acid resistance) capable of foaming operation without increasing the viscosity even when the pH is lowered. rice field.
As a method for imparting acid resistance to an oil-in-water emulsion, a method for devising an emulsifier formulation (Patent Document 2), a method for devising a protein type (Patent Document 3), and an acid resistance imparting agent such as fermented cellulose are used. A method of adding (Patent Document 4) has been proposed.

Japanese Patent No. 6612491 Japanese Unexamined Patent Publication No. 8-126470 Japanese Unexamined Patent Publication No. 2014-79234 JP-A-2015-57948

However, since the methods of Patent Documents 2 and 3 employ a specific emulsifier or a specific protein in order to impart acid resistance, the types of emulsifiers and proteins that can be blended are restricted. For this reason, there is little room for devising the composition of emulsifiers and proteins in product design, and there is a problem that the degree of freedom in product design is reduced.
In the method of Patent Document 4, the flavor of the oil-in-water emulsion is different from the original flavor by blending an originally unnecessary acid resistance imparting agent in order to impart acid resistance, and the cost of the product is increased. There was a problem that it became high. In addition, this method also has a problem that the degree of freedom in product design is lowered.
Further, in the conventional technique, even if the oil-in-water emulsion to which an acidic material is added can be foamed, the shape-retaining property of the obtained whipped cream is not sufficient, and the hardness of the whipped cream is increased over time. Sometimes it was easy to drop.
Therefore, it is possible to foam when an acidic material is added without being restricted by a specific raw material or by blending an originally unnecessary component, and product design can be freely performed, and shape retention after foaming is possible. There is a need for a technology that can produce an excellent underwater oil-type emulsion.

One aspect of the present invention is a method for producing an oil-in-water emulsion, which can be foamed when an acidic material is added and can produce an oil-in-water emulsion having excellent shape retention after foaming. A method for producing a bubble-containing oil-in-water emulsion, a method for producing a frozen bubble-containing oil-in-water emulsion, a method for producing an acidic oil-in-water emulsion, a method for producing an acidic oil-in-water emulsion containing bubbles, and an acidic material. It is an object of the present invention to provide an oil-in-water emulsion which can be foamed when added and has excellent shape retention after foaming.

[1] The first oil-in-water emulsion which is homogenized by homogenizing the first oil-in-water emulsion which contains fat and water and has a protein content of less than 1.4% by mass. The process of obtaining and
A method for producing an oil-in-water emulsion, which comprises a step of mixing the homogenized first oil-in-water emulsion and a protein-containing raw material to obtain a second oil-in-water emulsion.
[2] The method for producing an oil-in-water emulsion according to [1], wherein the second oil-in-water emulsion is not homogenized after the step of obtaining the oil-in-water emulsion.
[3] The method for producing an oil-in-water emulsion according to [1] or [2], wherein the oil-in-water emulsion content of the first oil-in-water emulsion is 1 to 60% by mass.
[4] The method for producing an oil-in-water emulsion according to any one of [1] to [3], wherein the protein content of the second oil-in-water emulsion is 0.4% by mass or more and less than 5% by mass. ..
[5] The pH of the oil-in-water emulsion produced by the above-mentioned production method is 6.5 to 7.5, the viscosity at 10 ° C. is 1 to 1000 mPa · s, and the pH of the oil-in-water emulsion is adjusted. The method for producing an oil-in-water emulsion according to any one of [1] to [4], wherein the viscosity at 10 ° C. at around 4.5 is less than 5810 mPa · s.
[6] Production of a bubble-containing oil-in-water emulsion produced by foaming the oil-in-water emulsion produced by the production method according to any one of the above [1] to [5] to form a bubble-containing oil-in-water emulsion. Method.
[7] A method for producing a frozen bubble-containing oil-in-water emulsion, wherein the bubble-containing oil-in-water emulsion produced by the production method according to the above [6] is frozen to form a frozen bubble-containing oil-in-water emulsion.
[8] An acidic material is added to the oil-in-water emulsion produced by the production method according to any one of the above [1] to [5], and the pH is adjusted to the range of 3.0 to 6.5 in acidic water. A method for producing an acidic oil-in-water emulsion, which is an oil-type emulsion.
[9] A method for producing a bubble-containing acidic oil-in-water emulsion, wherein the acidic oil-in-water emulsion produced by the production method according to the above [8] is foamed to form a bubble-containing acidic oil-in-water emulsion.
[10] An oil-in-water emulsion containing oil, water and protein.
The pH is 6.5-7.5 and
The viscosity at 10 ° C. is 1 to 1000 mPa · s, and the viscosity is 1 to 1000 mPa · s.
The viscosity of the oil-in-water emulsion at 10 ° C. when the pH was around 4.5 was less than 5810 mPa · s.
An oil-in-water emulsion in which the amount of protein precipitate measured by the following measuring method exceeds 0% by volume.
Method for measuring the amount of protein precipitate: 50 mL of the oil-in-water emulsion was placed in a centrifuge tube with a scale, and the mixture was centrifuged at a relative centrifugal acceleration of 1630 × g for 5 minutes using a centrifuge. The volume (mL) of the protein precipitated in the centrifuge tube is visually measured, and the ratio (% by volume) of the volume of the protein to the total volume of the oil-in-water emulsion is defined as the amount of protein precipitate.

According to the present invention, a method for producing an oil-in-water emulsion capable of producing an oil-in-water emulsion which can be foamed when made acidic and has excellent shape retention after foaming, and a bubble-containing product using this production method. A method for producing an oil-in-water emulsion, a method for producing an oil-in-water emulsion containing frozen bubbles, a method for producing an oil-in-water emulsion in acidic water, a method for producing an acidic oil-in-water emulsion containing bubbles, and an acidity. It is possible to provide an oil-in-water emulsion that can be foamed and has excellent shape retention after foaming.

It is a flow chart which shows the manufacturing method of the oil-in-water emulsion which concerns on one Embodiment. It is a flow chart which shows the manufacturing method of the oil-in-water emulsion which concerns on another embodiment. It is a flow chart which shows the manufacturing method of the oil-in-water emulsion which concerns on another embodiment. It is a flow chart which shows the manufacturing method of the oil-in-water emulsion which concerns on another embodiment. It is a flow chart which shows the manufacturing method of the oil-in-water emulsion which concerns on another embodiment. It is a graph which shows the acid resistance test result of Test Example 1. FIG. It is a graph which shows the acid resistance test result of Test Example 1. FIG. It is a scatter plot and a regression equation which show the relationship between the protein content of the 1st oil-in-water emulsion and the viscosity of a cream (oil-in-water emulsion) around pH 4.5. It is a graph which shows the acid resistance test result of Test Example 2. It is a graph which shows the acid resistance test result of Test Example 3.

In the present invention, the protein content of the oil-in-water emulsion can be calculated by calculation from the protein content of the raw material and its formulation.
However, in general, the protein content can also be measured by the semi-micro Kjeldahl method (14th revised Japanese Pharmacy Manual, General Regulations for Manufacturing, General Test Method 2001 B-370 to B374). A specific measurement method is shown below.
Approximately 1 g of the sample (measure the mass of the sample to the unit of 0.1 mg) is collected, and the amount of nitrogen in the sample is quantified by the semi-micro Kjeldahl method. Specifically, the sample is placed in a decomposition bottle, 1 g of a decomposition accelerator having a composition of potassium sulfate: copper sulfate = 10: 1 (mass ratio), and 7 mL of concentrated sulfuric acid are added, and the sample is decomposed by heating. After thermal decomposition, the sample is subjected to steam distillation, and the distilled sample is received in 20 mL of a 20 mM sulfuric acid aqueous solution. When the distillation is completed, a 20 mM aqueous sulfuric acid solution that has received distilled water is titrated with 40 mM sodium hydroxide. The titration amount at that time is b (mL). When a blank test is performed using a control sample containing no protein instead of the sample and the titration amount at that time is a (mL), the protein content of the sample is calculated by the following formula.
Protein content (% by mass) = (0.56 x (ba) x 6.38) / sample weight (g) / 1000 x 100
By the way, 0.56 in the formula is the amount of nitrogen in the sample for 1 mL of 40 mM sodium hydroxide, and 6.38 is the coefficient for converting the amount of nitrogen into the protein of dairy products.
In the present invention, the oil and fat content of the oil-in-water emulsion can also be calculated from the composition of the raw materials.
However, in general, the content of fats and oils can also be measured by the Reesegotleave method (Food Sanitation Inspection Guideline, Physics and Chemistry, 2005, p. 48-49: supervised by the Ministry of Health, Labor and Welfare). A specific measurement method is shown below.
First, 1 g of a sample is collected in a beaker and transferred to an extraction tube while washing the inside of the beaker with about 10 mL of warm water. Add 2 mL of ammonia water and 1 drop of phenolphthalein reagent to the extraction tube, plug it, and mix well. Then, using 10 mL of ethanol, add the beaker from which the sample was taken to the extraction tube while washing, plug it, and mix well. Next, add 25 mL of ether, plug it, and shake vigorously for 30 seconds. Finally, add 25 mL of petroleum ether, plug and shake vigorously for 30 seconds. After allowing the upper layer to stand until it becomes transparent, decantation is performed on a pre-constant amount of dish so as not to spill the ether layer, and the organic solvent is recovered. The dish is placed in a steam dryer at 100 ° C. to 105 ° C. for 1 hour to evaporate the organic solvent. The amount of extracted fat (g) can be measured by measuring the mass of this dish. The oil and fat content is calculated from these measured values by the following formula.
Fat content (mass%) = (extracted fat amount / sample amount used) x 100
Viscosity is measured by a B-type viscometer.
The pH is a value at 10 ° C. unless otherwise specified.
The relative centrifugal acceleration is calculated by the following formula.
RCF = 1118 × r × N ² × ^10-8
Here, RCF indicates a relative centrifugal acceleration (× g), r indicates a maximum turning radius (cm), and N indicates a rotation speed (rpm) per minute.
As used herein, the term "excellent in acid resistance" means that foaming is possible when an acidic material is added and that the shape retention after foaming is excellent.

[Manufacturing method of oil-in-water emulsion]
The method for producing an oil-in-water emulsion according to one aspect of the present invention (hereinafter, also referred to as "the present production method") is the first method containing oil and fat and water, and having a protein content of less than 1.4% by mass. A step of homogenizing the oil-in-water emulsion to obtain a homogenized first oil-in-water emulsion (hereinafter, also referred to as a “homogenization step”) and a homogenized first oil in water. It has a step of mixing a mold emulsion and a protein-containing raw material to obtain a second oil-in-water emulsion (hereinafter, also referred to as a “mixing step”).
The first oil-in-water emulsion, protein-containing raw material and second oil-in-water emulsion will be described in detail later.

In this production method, it is preferable not to homogenize the second oil-in-water emulsion after the mixing step.
"Do not homogenize the second oil-in-water emulsion" here means that the mechanical operation of finely dividing the fat globules in the second oil-in-water emulsion is not intentionally performed. Meaning. If the fat globules are naturally crushed by an impact or the like during the handling of the second oil-in-water emulsion, it is included in the "homogenization of the second oil-in-water emulsion" here. I can't.

In this production method, before the homogenization step, the oil phase portion containing oil and fat and the aqueous phase portion containing water are mixed (pre-mixing) and emulsified (pre-emulsified) with a mixing device such as a homomixer. It may have a step of preparing a first oil-in-water emulsion (hereinafter, also referred to as "preliminary emulsification step").
Prior to the pre-emulsification step, the oil and fat are heated and melted, and if necessary, other oil-soluble components (such as the first emulsifier described later) are dissolved in the fat and oil to prepare an oil phase portion. May be good.
Before the pre-emulsification step, water is used as it is as the aqueous phase part, or other water-soluble components (second emulsifier, protein-containing raw material, chelating agent, etc. described later) are added to the water to prepare the aqueous phase part. You may have a step to do.
Prior to the homogenization step, there may be a step of heating (preheating) the first oil-in-water emulsion.
It may have a step of sterilizing the first oil-in-water emulsion before or after the homogenization step.
After the homogenization step, there may be a step of aging the first oil-in-water emulsion.
Prior to the mixing step, there may be a step of sterilizing the protein-containing raw material.
Prior to the mixing step, there may be a step of homogenizing the protein-containing raw material. However, the protein-containing raw material typically does not contain fats and oils, and in this case, the protein-containing raw material itself does not have to be homogenized.
After the mixing step, there may be a step of sterilizing the second oil-in-water emulsion.
After the mixing step, there may be a step of aging the second oil-in-water emulsion.
The oil-in-water emulsion produced by this production method is typically a second oil-in-water emulsion, an aged second oil-in-water emulsion, or a second oil-in-water emulsion. The thing is sterilized and aged.
Hereinafter, the oil-in-water emulsion produced by the present production method is also referred to as "the oil-in-water emulsion of the present invention".

Hereinafter, the present manufacturing method will be described with reference to the attached drawings by showing embodiments.
FIG. 1 is a flow chart showing an embodiment of the present manufacturing method.
In the present embodiment, first, the fat and oil of the raw materials are heated and melted, and if necessary, other oil-soluble components are dissolved in the fat and oil to prepare an oil phase portion. Separately, of the raw materials, water is used as it is as the aqueous phase portion, or other water-soluble components are dissolved in water to prepare the aqueous phase portion. These preparations are carried out by heating fats and oils or water to an appropriate temperature.
Next, the oil phase portion and the aqueous phase portion are put into a tank equipped with, for example, a stirrer, and both are premixed. After that, for example, a stirrer is operated to sufficiently stir the oil phase portion and the aqueous phase portion to pre-emulsify. As a result, the first oil-in-water emulsion is prepared. It is necessary to keep the protein content of the first oil-in-water emulsion low, and the protein content of the first oil-in-water emulsion is less than 1.4% by mass.

Next, the first oil-in-water emulsion is passed through a UHT sterilizer integrated with a homogenizer. The homogenizer integrated UHT sterilizer is usually equipped with a heat exchanger and a homogenizer. The first oil-in-water emulsion is first preheated by a heat exchanger and preferably heated to 65 to 75 ° C. It is then homogenized by a homogenizer. The set pressure (homo pressure) for homogenization of the first oil-in-water emulsion is preferably 1.0 to 15.0 MPa, more preferably 3.0 to 15.0 MPa, and further preferably 5.0 to 12.0 MPa. preferable. The homo pressure is a gauge pressure. The homogenized first oil-in-water emulsion is heated to a predetermined sterilization temperature and held for a predetermined time to be sterilized. The sterilization conditions are not particularly limited, and the sterilization conditions can be known. For example, heating at 90 ° C. for 15 seconds, or heating conditions that can obtain an equivalent bactericidal effect can be mentioned. The homogenized first oil-in-water emulsion is then cooled. As a UHT sterilizer integrated with a homogenizer, there is also a model that performs homogenization after sterilization and before cooling, and such a model may be adopted.
The cooled first oil-in-water emulsion is stored in a tank having a cooling function.

Separately, the protein-containing raw material is sterilized and cooled. The sterilization conditions are not particularly limited, and the sterilization conditions can be known. For example, heating at 90 ° C. for 15 seconds, or heating conditions that can obtain an equivalent bactericidal effect can be mentioned.
Then, the protein-containing raw material is mixed with the stored first oil-in-water emulsion. This prepares a second oil-in-water emulsion. The mixing amount of the protein-containing raw material is set according to the target value of the protein content of the second oil-in-water emulsion. That is, the protein content of the first oil-in-water emulsion is kept low, and the protein-containing raw material is additionally mixed to finally adjust the protein content to a desired value.
Then, by aging the second oil-in-water emulsion, the oil-in-water emulsion of the present invention can be obtained. Aging is a treatment that promotes fat crystallization and can be performed according to a conventional method. The aging conditions are not particularly limited, and known aging conditions can be used. For example, the condition of 3.0 to 6.0 ° C. for 8 to 10 hours can be mentioned.
After mixing the homogenized first oil-in-water emulsion with the protein-containing material, the second oil-in-water emulsion can be agitated to evenly mix them, for example during aging. .. Stirring can be performed using a known stirrer. At this time, in order to suppress a decrease in acid resistance of the second oil-in-water emulsion, it is preferable to stir as slowly as possible. At this point, the cooled first oil-in-water emulsion is stored in a tank equipped with a cooling function such as a double jacket, which is attached with a slowly rotating stirring blade, and is stirred in the tank by the stirring blade. Is desirable.

<First oil-in-water emulsion>
The first oil-in-water emulsion contains oils and fats and water.
The first oil-in-water emulsion may contain a protein as long as the protein content is less than 1.4% by mass.
The first oil-in-water emulsion may further contain at least one selected from the group consisting of emulsifiers, stabilizers and salts.
The first oil-in-water emulsion may further contain other components other than the above.

Examples of fats and oils include vegetable fats and oils, animal fats and oils, and the like. Vegetable oils and fats include palm oil, palm kernel oil, palm oil, rapeseed oil, soybean oil, sunflower oil, cottonseed oil, peanut oil, rice oil, rice bran oil, corn oil, saflower oil, olive oil, capoc oil, sesame oil, and evening primrose oil. Such as plant-based; the plant-based oleic acid; the plant-based cured oil (partially cured oil, extremely cured oil), ester exchange oil, fractionated oil, mixed oil and the like. Examples of animal fats and oils include milk fats, beef fats, pork fats, fish oils, whale oils, their hardened oils (partially hardened oils and extremely hardened oils), ester exchange oils, fractionated oils and mixed oils. These fats and oils may be used alone or in combination of two or more.
From the viewpoint of cost and physical properties after whipping, it is preferable that at least a part of the fat is a vegetable fat. Vegetable fats and oils and animal fats and oils such as milk fat may be used in combination.
As for vegetable oils and fats, the solid fat content at the time of refrigeration (5 ° C.) is about 50 to 70% by mass, and 35 to 40 so that melting in the mouth can be obtained in the body temperature range when the oil-in-water emulsion is foamed. Those having a melting point of around ° C. are preferable. Examples of such vegetable oils and fats include rapeseed oil, soybean oil, palm oil, palm kernel oil, corn oil, cottonseed oil, rice oil, coconut oil, oleic acid and hydrogenated oil thereof. Of these, a mixed oil of palm olein and hydrogenated rapeseed oil, hydrogenated palm oil, and hydrogenated palm kernel oil are preferable. These may be used alone or in combination of two or more.

The protein is generally considered to contribute to the improvement of the stability of the oil-in-water emulsion and the improvement of the stability of the oil-in-water emulsion containing bubbles in which the oil-in-water emulsion is foamed. However, in the present invention, the protein content of the first oil-in-water emulsion is limited to less than 1.4% by mass. The idea of lowering the protein content of the first oil-in-water emulsion is extremely rare in the technical field of the present invention.
Examples of the protein include milk protein and soybean protein, and milk protein is preferable from the viewpoint of flavor.
Then, in the present invention, the protein is typically blended in the first oil-in-water emulsion in the form of a protein-containing raw material. Examples of the protein-containing raw material include the same as the protein-containing raw material used in the mixing step.

Emulsifiers, stabilizers and salts contribute to the improvement of the stability (emulsification stability) of oil-in-water emulsions.
Examples of the emulsifier include lecithin, polyglycerin fatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester, polysorbate, organic acid monoglyceride, fatty acid monoglyceride and the like. These emulsifiers may be used alone or in combination of two or more.

The emulsifier preferably contains a polyglycerin fatty acid ester because of its excellent solubility in water.
The content of the polyglycerin fatty acid ester is preferably 30 to 100% by mass, more preferably 50 to 100% by mass, based on the total mass of the emulsifier.
Polyglycerin fatty acid ester may be used in combination with other emulsifiers. As the other emulsifier, at least one selected from the group consisting of lecithin and sucrose fatty acid ester is preferable in terms of emulsion stability during the production process, flavor of foaming oil-in-water emulsion, and foaming property.

The emulsifier preferably contains a first emulsifier having an HLB (hydrophilic lipophilic oil balance) value of 6 or less and a second emulsifier having an HLB value of 10 to 16.
The first emulsifier is mainly contained in the oil phase. The second emulsifier is mainly contained in the aqueous phase. By using the first emulsifier and the second emulsifier in combination, the emulsion stability of the oil-in-water emulsion and the physical characteristics at the time of foaming are more excellent.
The HLB value of the first emulsifier is preferably 1 to 6.
The HLB value of the second emulsifier is preferably 10 to 16.
In the present specification, the HLB value is a value obtained by the Griffin method.

As the first emulsifier, for example, an emulsifier having an HLB value of 6 or less can be appropriately selected from the emulsifiers listed above.
The first emulsifier preferably contains at least one selected from the group consisting of lecithin and a sucrose fatty acid ester having an HLB value of 6 or less because it is easy to emulsify when foaming an oil-in-water emulsion. .. Examples of the sucrose fatty acid ester having an HLB value of 6 or less include Ryoto Sugar Ester P-170 (Mitsubishi Chemical Foods).
The content of at least one emulsifier selected from the group consisting of lecithin and a sucrose fatty acid ester having an HLB value of 6 or less is preferably 20 to 100% by mass, preferably 50 to 100% by mass, based on the total mass of the first emulsifier. % Is more preferable.

At least one selected from the group consisting of lecithin and a sucrose fatty acid ester having an HLB value of 6 or less may be used in combination with another emulsifier having an HLB value of 6 or less.
As the other emulsifier having an HLB value of 6 or less, a polyglycerin fatty acid ester having an HLB value of 6 or less is preferable. The HLB value of the polyglycerin fatty acid ester can be widely adjusted depending on the constituent fatty acids, the degree of polymerization and the like.

As the second emulsifier, for example, an emulsifier having an HLB value of 10 to 16 can be appropriately selected from the emulsifiers listed above.
The second emulsifier preferably contains a polyglycerin fatty acid ester having an HLB value of 10 to 16 because of its excellent solubility in water.
The content of the polyglycerin fatty acid ester having an HLB value of 10 to 16 is preferably 50 to 100% by mass, more preferably 80 to 100% by mass, based on the total mass of the second emulsifier.

A polyglycerin fatty acid ester having an HLB value of 10 to 16 may be used in combination with another emulsifier having an HLB value of 10 to 16.
As the other emulsifier having an HLB value of 10 to 16, a sucrose fatty acid ester having an HLB value of 10 to 16 is preferable because it is easily emulsified when the oil-in-water emulsion is foamed.

Examples of the stabilizer include gums such as xanthan gum and carrageenan; proteins such as casein, soy protein and gelatin; polysaccharides such as starch, modified starch, sodium alginate and carboxymethyl cellulose.
Examples of salts include phosphates such as monophosphate and condensed phosphate.

Other components include, for example, chelating agents (trisodium citrate, etc.), pH regulators, milk components, egg components, sugars (lactose, fructose, glucose, sugar, etc.), dietary fiber, cellulose, fragrances, pigments. And so on.

It is also possible to further combine the present invention with the above-mentioned prior art.
For example, in the present invention, the acid resistance imparting agent is not always necessary, but the inclusion of the acid resistance imparting agent is not excluded. As the acid resistance imparting agent in this case, known ones can be used, and examples thereof include fermented cellulose (Patent Document 4: JP-A-2015-57948).
Even if the acid resistance imparting agent is blended, the content of the acid resistance imparting agent is 3% by mass or less with respect to the total mass of the finally obtained second oil-in-water emulsion in terms of flavor. Is preferable. The content of the acid resistance imparting agent is particularly preferably 0% by mass with respect to the total mass of the second oil-in-water emulsion.
Further, in the present invention, other conventional techniques, for example, a method of devising the composition of an emulsifier (Patent Document 2) and a method of devising the type of protein (Patent Document 3), are used as specific emulsifiers in order to obtain acid resistance. It is not necessary to be constrained and it is not necessary to add a milk protein decomposition product for the purpose of acid resistance, but it is not excluded to combine these prior arts with the present invention.
As described above, even if it is assumed that the conventional technique is combined with the present invention, there is an advantage that the degree to which the conventional technique is performed can be suppressed to be smaller than the case where such a conventional technique is performed alone.

In the first oil-in-water emulsion, the content of fats and oils is preferably 20 to 70% by mass, more preferably 40 to 60% by mass, based on the total mass of the first oil-in-water emulsion. When the oil / fat content is at least the lower limit of the above range, the oil / fat content of the finally obtained second oil-in-water emulsion is likely to be within the preferable range described later.

The water content is preferably 20 to 70% by mass, more preferably 30 to 50% by mass, based on the total mass of the first oil-in-water emulsion. When the water content is not less than the lower limit of the above range, the emulsifying property is more excellent, and when it is not more than the upper limit value of the above range, the foaming property of the second oil-in-water emulsion is more excellent.

The protein content is less than 1.4% by mass, preferably 0.8% by mass or less, more preferably 0.4% by mass or less, and 0% by mass, based on the total mass of the first oil-in-water emulsion. % Is particularly preferable. That is, it is particularly preferable that the first oil-in-water emulsion does not contain protein. When the protein content is not more than the above upper limit, the oil-in-water emulsion of the present invention has excellent acid resistance, and the oil-in-water emulsion of the present invention has an acidic foaming property. And, the bubble-containing acidic oil-in-water emulsion obtained by foaming the oil-in-water emulsion is excellent in shape retention.

In the first oil-in-water emulsion, the ratio of protein to fat (100% by mass) is preferably less than 2.82% by mass, more preferably 2.0% by mass or less, still more preferably 1.6% by mass or less. , 1.0% by mass or less is more preferable, 0.8% by mass or less is particularly preferable, and 0% by mass is most preferable. When the ratio of the protein to the fat is not more than the above upper limit, the acid resistance of the oil-in-water emulsion of the present invention is more excellent, the foaming property of the oil-in-water emulsion of acid is high, and the oil-in-water emulsion containing bubbles is used. Excellent shape retention.

The content of the emulsifier is preferably 0.3 to 1.5% by mass, more preferably 0.5 to 1.0% by mass, based on the total mass of the first oil-in-water emulsion. When the content of the emulsifier is at least the lower limit of the above range, the smoothness and shape retention of the bubble-containing acidic oil-in-water emulsion is more excellent, and when it is at least the upper limit of the above-mentioned range, the bubble-containing acidic oil-in-water emulsion is emulsified. Excellent shape retention and flavor.

When the emulsifier contains the first emulsifier and the second emulsifier, the content of the first emulsifier is 30 to 70% by mass with respect to the total mass of the first emulsifier and the second emulsifier, and the content of the second emulsifier is contained. The amount is preferably 30 to 70% by mass, more preferably 40 to 60% by mass of the first emulsifier and 40 to 60% by mass of the second emulsifier.

The pH of the first oil-in-water emulsion is preferably 6.0 to 8.0, more preferably 6.5 to 7.5. When the pH is at least the lower limit of the above range, the stability of the liquid state is more excellent, and when it is at least the upper limit of the above range, the flavor and foaming property are more excellent.

The viscosity of the first oil-in-water emulsion at 10 ° C. is preferably 20 to 1000 mPa · s, more preferably 30 to 500 mPa · s. When the viscosity of the first oil-in-water emulsion is within the above range, the viscosity of the second oil-in-water emulsion at 10 ° C. is likely to be within the preferable range described later.

<Protein-containing raw material>
The protein-containing raw material contains protein.
The protein-containing raw material may contain components other than protein. Examples of the component other than the protein include the above-mentioned other components and water. The other components used in the mixing step are preferably water-soluble components.
The protein-containing raw material may be liquid or solid (particulate, powdery, etc.), but is liquid because it is easily mixed with the homogenized first oil-in-water emulsion. It is preferable to have. Examples of the liquid protein-containing raw material include skim milk concentrate, skim milk concentrate, skim milk powder solution, skim milk powder solution and the like. Other components may be added to these liquid protein-containing raw materials.
Further, since it is preferable that the protein-containing raw material is not homogenized after the mixing step, it is preferable that the content of fats and oils is low. The content of fats and oils in the protein-containing raw material is preferably 1.0% by mass or less, more preferably 0.5% by mass or less, still more preferably approximately 0% by mass, and 0% by mass, based on the total mass of the protein-containing raw material. Is particularly preferable. In addition, "substantially 0% by mass" means that the finally obtained oil-in-water emulsion of the present invention is preserved without homogenization of the protein-containing raw material or the second oil-in-water emulsion. It means a trace amount that does not cause fat levitation between.

<Second oil-in-water emulsion>
The second oil-in-water emulsion is obtained by mixing the first oil-in-water emulsion with a protein-containing raw material, and contains at least oil, water, and protein.
The second oil-in-water emulsion may further contain an emulsifier.
The second oil-in-water emulsion may further contain other components.
The content of each of the oil, water, protein, emulsifier, and other components with respect to the total mass of the second oil-in-water emulsion is the oil, water, and water with respect to the total mass of the oil-in-water emulsion and the protein-containing raw material. It should be equal to the content of each of the protein, emulsifier and other ingredients. However, when the first oil-in-water emulsion and the protein-containing raw material are mixed, it is not excluded to mix other components together.

The content of the fat and oil is preferably 20 to 60% by mass, more preferably 30 to 50% by mass, based on the total mass of the second oil-in-water emulsion. When the content of fats and oils is not less than the lower limit of the above range, a good texture and flavor can be easily obtained when foamed, and when it is not more than the upper limit of the above range, the flavor when foamed is easily obtained. Better.

The water content is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, based on the total mass of the second oil-in-water emulsion. When the water content is not less than the lower limit of the above range, the flavor and smoothness at the time of foaming are more excellent, and when it is not more than the upper limit of the above range, the flavor at the time of foaming is more excellent.

The protein content is preferably 0.1 to 5.0% by mass, more preferably 0.2 to 3.0% by mass, based on the total mass of the second oil-in-water emulsion. When the protein content is at least the above lower limit value, the emulsion stability before foaming is more excellent, and when it is at least the above upper limit value, the acid resistance of the second oil-in-water emulsion is more excellent.

The content of the emulsifier is preferably 0.1 to 2.0% by mass, more preferably 0.3 to 1.5% by mass, based on the total mass of the second oil-in-water emulsion. When the content of the emulsifier is at least the lower limit of the above range, the emulsification stability before foaming is more excellent, and when it is at least the upper limit of the above range, the flavor at the time of foaming is more excellent.

When the emulsifier contains the first emulsifier and the second emulsifier, the content of the first emulsifier is 30 to 70% by mass with respect to the total mass of the first emulsifier and the second emulsifier, and the content of the second emulsifier is contained. The amount is preferably 30 to 70% by mass, more preferably 40 to 60% by mass of the first emulsifier and 40 to 60% by mass of the second emulsifier.

<Oil-in-water emulsion of the present invention>
The oil-in-water emulsion of the present invention, like the second oil-in-water emulsion, contains at least fats and oils, water and protein.
The second oil-in-water emulsion may further contain an emulsifier.
The second oil-in-water emulsion may further contain other components.
The content of each of the fat, water, protein, emulsifier, and other components with respect to the total mass of the oil-in-water emulsion of the present invention is the fat, water, protein, emulsifier, etc. with respect to the total mass of the oil-in-water emulsion of the second. It is desirable that it is equal to the content of each of the components of.

The oil-in-water emulsion of the present invention typically has foaming properties. For example, when the oil-in-water emulsion of the present invention is foamed at 6 to 10 ° C., a foamed product having an overrun of 80 to 180% can be obtained. The overrun is preferably 100 to 160%, more preferably 120 to 150%. Overrun is determined by the method described in Examples described later.

The oil-in-water emulsion of the present invention may be a liquid cream.
"Liquid cream" means a cream that is not substantially foamed, in other words, a cream that has not been artificially foamed.
"Cream" is a emulsion prepared using raw materials containing fat, and is a cream specified by the Ordinance of the Ministry of Milk, etc. (Ministry Ordinance on Ingredient Standards for Milk and Milk Products) (hereinafter, also referred to as "fresh cream"). ), And creams classified as "milk or dairy-based foods" specified by the Ordinance of the Ministry of Milk, etc. (hereinafter, also referred to as "milk main cream"). Fresh cream is "raw milk, milk, or special milk from which components other than milk fat have been removed". The milk main cream contains ingredients other than milk fat (vegetable fat, protein, various additives (embroidery, stabilizer, fragrance, etc.), etc.) and contains only milk fat as fat (pure milk fat). Cream), a mixed type containing milk fat and vegetable fat as a fat (so-called compound cream), and a pure vegetable fat type containing only vegetable fat as a fat (so-called non-daily cream).
The oil-in-water emulsion of the present invention can be applied to various oil-in-water emulsions, but in order to maximize the effects of the present invention, the oil-in-water emulsion that has not been fermented is used. It can be said that it is more suitable. Further, as the oil-in-water emulsion having foaming property, it is preferable that the emulsion does not contain a component for coagulating bubbles such as gelatin and egg white. From this point of view, whipping cream is particularly preferable to sour cream, mousse cream, and bavarois cream.

The pH of the oil-in-water emulsion of the present invention is preferably 6.0 to 8.0, more preferably 6.5 to 7.5. When the pH of the oil-in-water emulsion of the present invention is at least the lower limit of the above range, the emulsion stability before foaming is more excellent, and when it is at least the upper limit of the above range, the flavor at the time of foaming is more excellent. Excellent.

The viscosity of the oil-in-water emulsion of the present invention at 10 ° C. varies depending on the pH, but for example, when the pH is 6.5 to 7.5, 1 to 1000 mPa · s is preferable, and 50 to 700 mPa · s is preferable. More preferably, 100 to 500 mPa · s is even more preferable. When the viscosity of the oil-in-water emulsion of the present invention is at least the lower limit of the above range, the texture and flavor after foaming are more excellent, and when it is at least the upper limit of the above range, the foaming property and flavor are obtained. Is better.

Further, the oil-in-water emulsion of the present invention has a viscosity of less than 5810 mPa · s, further less than 5394 mPa · s, and further less than 5000 mPa · s when the pH is around 6.5 to 7.5 to 4.5. Further, 4660 mPa · s or less, further less than 4498 mPa · s, further less than 4049 mPa · s, further 4000 mPa · s or less, further 3390 mPa · s or less, further less than 3153 mPa · s, further 2000 mPa · s or less, Further, it is preferably 1400 mPa · s or less. Around pH 4.5 is typically pH 4.45 to 4.60. The oil-in-water emulsion of the present invention has substantially the same viscosity within this range. Since the isoelectric point of casein is around pH 4.5, the viscosity of the oil-in-water emulsion of the present invention tends to be the highest around pH 4.5. The lower the viscosity at pH 4.5, the better the acid resistance. Further, if the viscosity at pH 4.5 is not more than the upper limit value, foaming can be sufficiently performed. In particular, when the viscosity is 4000 mPa · s or less, the overrun is good, and when it is 2000 mPa · s or less, it is even better.
The viscosity of the oil-in-water emulsion of the present invention when the pH is around 6.5 to 7.5 to 4.5 is preferably 50 mPa · s or more in terms of the flavor when foamed. , 100 mPa · s or more is more preferable.

<Action effect>
In the embodiment described above, the protein content of the oil-in-water emulsion to be homogenized (first oil-in-water emulsion) is set to less than 1.4% by mass, and the protein-containing raw materials are mixed after homogenization. However, since the obtained second oil-in-water emulsion is not homogenized as much as possible, the oil-in-water emulsion having excellent acid resistance while containing protein (oil-in-water emulsion of the present invention). Is obtained. The acidic oil-in-water emulsion obtained by adding an acidic material to the oil-in-water emulsion of the present invention can foam well, and the bubble-containing acidic oil-in-water emulsion obtained by foaming the acidic oil-in-water emulsion has shape retention. Excellent for.
The reason for the excellent acid resistance is not clear, but the hypothesis is as follows.
That is, conventionally, when producing an oil-in-water emulsion containing a protein, the homogenized oil-in-water emulsion generally contains 1.4% by mass or more of protein. When such an oil-in-water emulsion is homogenized, many proteins are attached to the surface of the emulsified film of crushed oil droplets. Therefore, it is considered that when the pH was lowered, the oil droplets aggregated with each other due to the aggregation of proteins, and the viscosity was easily increased.
On the other hand, in this production method, since the first homogenized oil-in-water emulsion contains or has a small amount of protein, when this is homogenized, the protein is on the surface of the emulsified film of the oil droplet. Does not adhere, or even if it adheres, the amount is very small. Then, after the protein-containing raw material is mixed with such a first oil-in-water emulsion to form a second oil-in-water emulsion, homogenization is not performed as much as possible. Therefore, even in the oil-in-water emulsion of the present invention, the state of the oil droplets of the first oil-in-water emulsion is maintained as it is. As a result, the oil-in-water emulsion of the present invention is less likely to cause protein aggregation and thickening even when the pH is lowered, so that good foaming property can be obtained and the hardness after foaming is not easily lowered. , It is considered to have excellent shape retention. The above is a hypothesis added just in case, for the purpose of explaining the technical content of the present invention in an easy-to-understand manner.

As described above, since the oil-in-water emulsion of the present invention has excellent acid resistance, it can be foamed even if it is made acidic by adding an acidic substance such as fruit juice or fruit. In addition, it can be used for various purposes because it can foam in both the neutral range and the acidic range.
Further, in the past, since an originally unnecessary component was blended in order to impart acid resistance, there were problems such as changes in taste and flavor and a low degree of freedom in product design. On the other hand, in this manufacturing method, since it is not necessary to add an originally unnecessary component, the taste and flavor do not change, and the degree of freedom in product design is high.

The manufacturing method is not limited to the above-described embodiment. Each configuration and a combination thereof in the above-described embodiment are examples, and the configurations can be added, omitted, replaced, and other changes within the scope not deviating from the gist of the present invention.
For example, the existing oil-in-water emulsion may be used. In this case, the pre-emulsification step may not be performed.
An example of homogenizing, sterilizing, and cooling the first oil-in-water emulsion using a homogenizer-integrated UHT sterilizer has been shown. However, the homogenizer-integrated UHT sterilizer is after sterilization and cooling. There is also a model that performs homogenization at the stage before, and such a model may be adopted. The homogenization and sterilization may be performed by different devices without using the UHT sterilizer integrated with the homogenizer. Homogenization can be performed using a known homogenizing machine. Sterilization can be performed using a known sterilization device.
When sterilization or aging is performed, the timing thereof and the timing of mixing the first oil-in-water emulsion and the protein-containing raw material are not limited to the above embodiments.

2 to 5 are flow charts showing another embodiment of the present manufacturing method, respectively.
In the embodiment shown in FIG. 1, a protein-containing raw material is mixed with a homogenized first oil-in-water emulsion to obtain a second oil-in-water emulsion, and then aging is performed. In the embodiment shown in the above, the protein-containing raw material is mixed during the aging of the homogenized first oil-in-water emulsion, and the aging is further continued. Specifically, while the homogenized first oil-in-water emulsion is stored in an aging tank and maintained at a low temperature, a protein-containing raw material is added and mixed in the aging tank. Generally, the aging tank is provided with a stirring blade for stirring at a low speed, and the mixing step is performed using the stirring blade. Then, the aging of the obtained second oil-in-water emulsion is continued as it is.
In the embodiment shown in FIG. 3, the homogenized first oil-in-water emulsion is aged and then the protein-containing raw material is mixed.
In the embodiment shown in FIG. 4, sterilization is performed after the mixing step. That is, the protein-containing raw material is mixed with the homogenized first oil-in-water emulsion to obtain a second oil-in-water emulsion, which is then sterilized. In this case, the protein-containing raw material does not need to be sterilized in advance. Then, the second oil-in-water emulsion after sterilization and cooling is aged. Even in this case, the second oil-in-water emulsion is not homogenized after the mixing step.
In the embodiment shown in FIG. 5, the homogenized first oil-in-water emulsion is pre-cooled after heat sterilization and then mixed with a protein-containing raw material whose temperature has been lowered after sterilization. The second oil-in-water emulsion obtained by mixing is then subjected to full-scale cooling and aging.
As described above, the mode of mixing the protein-containing raw material with the homogenized first oil-in-water emulsion can take various modes.
As described above, the protein content of the first oil-in-water emulsion is reduced to less than 1.4% by mass, but the protein-containing raw material is mixed with the first oil-in-water emulsion. Thus, the protein content of the second oil-in-water emulsion is finally higher than that of the first oil-in-water emulsion.

[Oil-in-water emulsion]
The oil-in-water emulsion according to one aspect of the present invention (hereinafter, also referred to as “main emulsion”) includes fats and oils, water and proteins.
The emulsion may further contain an emulsifier.
The emulsion may further contain components other than the above.

The fats and oils, proteins, emulsifiers, and other components are the same as described above, and the preferred embodiments are also the same.

The content of fats and oils is preferably 20 to 60% by mass, more preferably 30 to 50% by mass, based on the total mass of the emulsion. When the content of fats and oils is not less than the lower limit of the above range, a good texture and flavor can be easily obtained when foamed, and when it is not more than the upper limit of the above range, the flavor when foamed is easily obtained. Better.

The water content is preferably 30 to 70% by mass, more preferably 40 to 60% by mass, based on the total mass of the emulsion. When the water content is not less than the lower limit of the above range, the flavor and smoothness at the time of foaming are more excellent, and when it is not more than the upper limit of the above range, the flavor at the time of foaming is more excellent.

The protein content is preferably 0.1 to 5.0% by mass, more preferably 0.2 to 3.0% by mass, based on the total mass of the emulsion. When the protein content is at least the above lower limit value, the emulsion stability before bubbles is more excellent, and when it is at least the above upper limit value, the acid resistance of the present emulsion is more excellent.

The content of the emulsifier is preferably 0.1 to 2.0% by mass, more preferably 0.3 to 1.5% by mass, based on the total mass of the emulsion. When the content of the emulsifier is at least the lower limit of the above range, the emulsification stability before foaming is more excellent, and when it is at least the upper limit of the above range, the flavor at the time of foaming is more excellent.

When the emulsifier contains the first emulsifier and the second emulsifier, the content of the first emulsifier is 30 to 70% by mass and the content of the second emulsifier is based on the total mass of the first emulsifier and the second emulsifier. Is preferably 30 to 70% by mass, more preferably the content of the first emulsifier is 40 to 60% by mass, and the content of the second emulsifier is 40 to 60% by mass.

The emulsion typically has foaming properties. For example, when the present emulsion is foamed at 6 to 10 ° C., a foamed product having an overrun of 80 to 180% can be obtained. The overrun is preferably 100 to 160%, more preferably 120 to 150%. Overrun is determined by the method described in Examples described later.

The emulsion may be a liquid cream.
Although the present invention can be applied to various emulsions, it can be said that an unfermented emulsion is more suitable for maximizing the effects of the present invention. Further, as the foaming emulsion, it is preferable that the emulsion does not contain a component for coagulating bubbles such as gelatin and egg white. From this point of view, whipping cream is particularly preferable to sour cream, mousse cream, and bavarois cream.

The pH of this emulsion is 6.0 to 8.0, preferably 6.5 to 7.5. When the pH is at least the lower limit of the above range, the emulsification stability before foaming is excellent, and when the pH is at least the upper limit of the above range, the flavor at the time of foaming is excellent.

The viscosity of this emulsion at 10 ° C. is 1 to 1000 mPa · s, preferably 50 to 700 mPa · s, and more preferably 100 to 500 mPa · s. When the viscosity of the present emulsion is at least the lower limit of the above range, the texture and flavor when foamed are excellent, and when it is at least the upper limit of the above range, the foaming property and flavor are excellent.

Further, this emulsion has a viscosity of less than 5810 mPa · s, further less than 5394 mPa · s, further less than 5000 mPa · s, and further 4660 mPa · s when the pH is around 6.5 to 7.5 to 4.5. s or less, further less than 4498 mPa · s, further less than 4049 mPa · s, further 4000 mPa · s or less, further 3390 mPa · s or less, further less than 3153 mPa · s, further 2000 mPa · s or less, further 1400 mPa · s The following is preferable. Around pH 4.5 is typically pH 4.45 to 4.60. This emulsion has almost the same viscosity within this range. Since the isoelectric point of casein is around pH 4.5, the viscosity of this emulsion tends to be the highest around pH 4.5. The lower the viscosity at pH 4.5, the better the acid resistance. Further, if the viscosity near pH 4.5 is not more than the upper limit value, foaming can be sufficiently performed. In particular, when the viscosity is 4000 mPa · s or less, the overrun is good, and when it is 2000 mPa · s or less, it becomes even better.
When the pH of this emulsion is around 6.5 to 7.5 to 4.5, the viscosity is preferably 50 mPa · s or more, and 100 mPa · s or more in terms of the flavor when foamed. Is more preferable.

In this emulsion, the amount of protein precipitate measured by the following measuring method exceeds 0% by volume.
Method for measuring the amount of protein precipitate: Place 50 mL of a sample (oil-in-water emulsion) in a centrifuge tube with a scale, and centrifuge at a relative centrifugal acceleration of 1630 xg for 5 minutes using a centrifuge. The volume (mL) of the protein precipitated in the centrifuge tube is visually measured, and the ratio (% by volume) of the volume of the protein to the total volume of the oil-in-water emulsion is defined as the amount of protein precipitate.
The amount of protein precipitate is an index of the amount of protein present in a free state in the continuous phase (aqueous phase) of this emulsion. When the amount of protein precipitate exceeds 0% by volume, the acid resistance is excellent.
The protein precipitation amount of this emulsion is preferably 0.1% by volume or more. The upper limit of the amount of protein precipitate is not particularly limited, but is, for example, 2.0% by volume.

The emulsion can be produced, for example, by the above-mentioned production method.
Conventionally, in the production of an oil-in-water emulsion containing a protein, the aqueous phase portion containing the protein and the oil phase portion are usually mixed and then homogenized. In the oil-in-water emulsion thus obtained, oil droplets are scattered as dispersed phases in the aqueous phase which is a continuous phase, and the protein in the aqueous phase covers the surface of the oil droplets due to homogenization. It is presumed that they are firmly attached. Therefore, it is considered that the oil-in-water emulsion produced by the conventional method has a small amount of protein present in the continuous phase.
On the other hand, in the above-mentioned production method, since the protein content of the first oil-in-water emulsion is lower than before, oil droplets are obtained even after the first homogenized oil-in-water emulsion is homogenized. The amount of protein attached to the surface of is small. After that, the protein-containing raw materials are mixed, and after that, homogenization is not performed as much as possible, so that it is considered that there are many proteins present in the continuous phase.
However, the method for producing this emulsion is not limited to this.

The oil-in-water emulsion or the present emulsion produced by the present production method may be stored or distributed in the form of a package after being filled and sealed in a packaging container.
The packaging container is not particularly limited as long as it does not leak, and examples thereof include paper containers, plastic containers, and retort containers.
The oil-in-water emulsion filled in the packaging container is opened and used at the time of use (for example, at the time of foaming).

The oil-in-water emulsion or the present emulsion produced by this production method can be used for whipping, cooking and the like.
The oil-in-water emulsion or the present emulsion produced by this production method is particularly useful for whipping.

For whipping applications, the oil-in-water emulsion obtained by this production method or the emulsion is foamed to form an oil-in-water emulsion containing bubbles (whipped cream, etc.).
Here, the “foaming” is not particularly limited, but is to bring the oil-in-water emulsion into contact with physical stress such as stirring or air to contain bubbles. At this time, it is desirable to use a six-quarter to nine-minute stand.
Before foaming, a sugar may be added to the oil-in-water emulsion obtained by the present production method or the present emulsion.
The blending amount of the sugar is preferably 0 to 10% by mass with respect to the total mass of the oil-in-water emulsion obtained by the present production method or the present emulsion. When the blending amount of the sugar is not more than the above upper limit value, the flavor of the obtained bubble-containing oil-in-water emulsion is good.

The obtained bubble-containing oil-in-water emulsion may be frozen as it is to obtain a frozen bubble-containing oil-in-water emulsion.
The obtained bubble-containing oil-in-water emulsion may be used as a package of the oil-in-water emulsion containing frozen bubbles. For example, if the obtained bubble-containing oil-in-water emulsion is directly filled in a container and preferably sealed, a package of the oil-in-water emulsion containing bubbles can be obtained.
Before freezing, the bubble-containing oil-in-water emulsion may be filled in a packaging container and sealed for storage or distribution. After freezing, the frozen bubble-containing oil-in-water emulsion may be filled and sealed in a packaging container. It may be stored or distributed.

Since the oil-in-water emulsion or the emulsion obtained by this production method is provided with excellent acid resistance, even if the oil-in-water emulsion becomes acidic, it foams and contains bubbles in the oil-in-water emulsion. It can be an emulsion. Therefore, an acidic material can be added to the oil-in-water emulsion or the emulsion obtained by the present production method to adjust the pH to acidic to obtain an acidic oil-in-water emulsion. Further, this acidic oil-in-water emulsion can be foamed to form an acidic oil-in-water emulsion containing bubbles.
The pH of the oil-in-water emulsion is preferably 2.0 to 6.5, and more preferably 3.0 to 5.5 in terms of texture at the time of foaming.

Further, the oil-in-water emulsion obtained by the present production method or the oil-in-water emulsion obtained by foaming the emulsion has excellent acid resistance. Therefore, an acidic material can be added to the bubble-containing oil-in-water emulsion and the pH can be adjusted to be acidic to obtain a bubble-containing acidic oil-in-water emulsion.
The pH of the oil-in-water emulsion containing acidic bubbles is preferably 2.0 to 6.5, and more preferably 3.0 to 5.5 in terms of texture.

Examples of the acidic material include acidic compounds that can be used in foods, crushed substances of acidic foods, crushed substances and debris, and soups.
Examples of the acidic compound include organic acids such as citric acid, lactic acid, acetic acid, oxalic acid, glucuronic acid and carbonic acid; and inorganic acids such as phosphoric acid.

Examples of acidic foods include processed products of sour fruits and / or vegetables. Examples of processed products of acidic foods include sour fruit juice and pulp; sour vegetable juice and vegetable pieces. In addition, examples of processing of acidic foods include purees, pastes, sauces, jams, soups, etc., which may be used alone or in combination as appropriate.
Usually, "puree" refers to crushed and strained fruits and / or vegetables, which are raw or cooked. Further, the "paste" generally means a paste that is darker than puree. Examples of the "fruit sauce" include those obtained by thickening fruit puree such as starch and those using jam.
Examples of the fruit juice and pulp pieces include citrus fruits such as lemon, orange, sudachi, and daidai; strawberry, raspberry, grape, pineapple, blueberry, kiwi fruit, apple, and the like. Examples of the vegetable juice and vegetable pieces include tomatoes and the like.

As the acidic food, processed products of acidic fruits and / or vegetables are suitable.
As the processed product of acidic fruits and / or vegetables, one or more selected from crushed products, pressed products, juices, purees and sauces are suitable.
The amount of the acidic food added is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the oil-in-water emulsion or the oil-in-water emulsion containing bubbles. It is a department.
The oil-in-water emulsion or the present emulsion obtained by this production method can be used not only for acidic compounds and acidic foods but also for a wide range of foods and the like.

Conventionally, when producing an oil-in-water emulsion containing bubbles containing an acidic food, the production methods of "separate stand" and "co-stand" are generally used. Further, when producing an oil-in-water emulsion containing bubbles, other components such as gelatin may be blended.
"Kyoritsu" is a method for producing a bubble-containing oil-in-water emulsion, which comprises a step of mixing an acidic food and an oil-in-water emulsion and whipping to obtain a bubble-containing oil-in-water emulsion containing an acidic food. "Separate setting" is a step of foaming an oil-in-water emulsion to form an oil-in-water emulsion containing bubbles, and a mixture of the obtained oil-in-water emulsion containing bubbles and an acidic food to enter an acidic food. It is a method for producing a bubble-containing oil-in-water emulsion containing bubbles, which comprises a step of obtaining an oil-in-water emulsion containing bubbles.
Conventionally, when a general oil-in-water emulsion (for example, fresh cream) and an acidic food are mixed together and whipped, the texture of the oil-in-water emulsion obtained by the influence of the acidic food is sloppy. Become. Therefore, the bubble-containing oil-in-water emulsion obtained by "Kyoritsu" does not have a good texture and flavor. Therefore, in order to improve the texture and flavor, "separate stand" is usually used in small-quantity production at stores and the like. However, this "separate setting" requires at least two steps, and the work efficiency is poor. Therefore, in the case of mass production, a conventional method of adding a stabilizer or the like to produce a bubble-containing oil-in-water emulsion containing an acidic food by "Kyoritsu" has been adopted. The bubble-containing oil-in-water emulsion obtained in the above method tends to be difficult to improve the texture and flavor due to the influence of conventional stabilizers and the like.
Since the oil-in-water emulsion or the emulsion obtained by this production method has excellent acid resistance, it is acidic with a good texture and flavor by "Kyoritsu" without adding a conventional stabilizer or the like. It is possible to produce an oil-in-water emulsion containing bubbles containing food.

The obtained bubble-containing acidic oil-in-water emulsion may be frozen to obtain a frozen bubble-containing acidic oil-in-water emulsion.
Before freezing, the bubble-containing acidic oil-in-water emulsion may be filled in a packaging container and sealed for storage or distribution. After freezing, the frozen bubble-containing acidic oil-in-water emulsion may be filled and sealed in a packaging container. It may be stored or distributed.
The frozen bubble-containing acidic oil-in-water emulsion is thawed at the time of use and used as the bubble-containing acidic oil-in-water emulsion.

The obtained bubble-containing oil-in-water emulsion or bubble-containing acidic oil-in-water emulsion may be, for example, whipped cream; whipped cream containing acidic food; cake, pancake, confectionery, jelly, pudding, ice confectionery, frozen milk. Whipped cream for decoration of products, etc .; Can be used as whipped cream for wiener coffee, juice, beverages, etc. Examples of the whipped cream containing an acidic food include whipped cream containing a processed product of a sour fruit and / or a vegetable. For example, whipped cream containing fruit and / or vegetable puree, whipped cream containing fruit and / or vegetable juice (for example, whipped cream containing citrus fruit juice, etc.) and the like can be mentioned.

As a food using an oil-in-water emulsion or an acidic oil-in-water emulsion, or an oil-in-water emulsion containing bubbles or an acidic oil-in-water emulsion containing bubbles, a lemon-flavored whipped cake with a more fruity feel is given. Roll cakes and tart with cream, short cakes and decoration cakes with tangerine-flavored whipped cream, jelly and pudding with strawberry-flavored whipped cream, and sandwiches with whipped cream seasoned with fruit juice. , Cream with fruit juice, cream puff with filling, bread making, etc.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples. In the following description, "%" indicates "mass%" except for% of overrun unless otherwise specified. "Part" indicates "part by mass". The creams of Examples 1 to 8 correspond to the oil-in-water emulsion of the present invention.

<Test Example 1>
(Cream production)
In this test example, five kinds of creams were produced as oil-in-water emulsions according to Table 1. The overall composition of these creams is the same. The overall composition of each cream is shown in Table 2. The procedure for producing each cream is as follows. That is, first, the aqueous phase portion and the oil phase portion are prepared separately, and these are premixed to obtain a first oil-in-water emulsion. Separately, a protein-containing raw material is prepared. The first oil-in-water emulsion and the protein-containing raw material are mixed to obtain a second oil-in-water emulsion. Then, the second oil-in-water emulsion is aged to obtain the creams of Examples 1 to 3 and Comparative Examples 1 and 2.
This test example was conducted to evaluate the effect of the protein concentration of the first oil-in-water emulsion on the acid resistance of the finally obtained cream (oil-in-water emulsion).

Details of the procedure for producing the cream of each example are shown below.
In Examples 1 to 3 and Comparative Example 1, first, according to the composition of the aqueous phase portion in Table 1, the emulsifier and skim milk powder were dissolved in water while stirring to prepare the aqueous phase portion. As the emulsifier in the aqueous phase portion, the following two types of emulsifiers A and B were used in a mass ratio of emulsifier A: emulsifier B = 2: 1. The fatty acids constituting the polyglycerin fatty acid ester are different between the emulsifiers A and B.
Emulsifier A: Polyglycerin fatty acid ester (manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB about 12).
Emulsifier B: Polyglycerin fatty acid ester (manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB approx. 12).
Further, according to the composition of the oil phase portion in Table 1, the emulsifier and soybean lecithin were dissolved in vegetable oil to prepare the oil phase portion. As the emulsifier of the oil phase part, polyglycerin fatty acid ester (manufactured by Sakamoto Pharmaceutical Co., Ltd., HLB about 5) was used. Palm kernel oil was used as the vegetable oil.
Next, the aqueous phase portion was heated to 70 ° C. while stirring, and the oil phase portion also heated to 70 ° C. was added thereto and premixed to prepare a synthetic portion. This synthetic part was pre-emulsified by stirring at 7000 rpm for 3 minutes using a homomixer to obtain a first oil-in-water emulsion. The protein content of the first oil-in-water emulsion is shown in Table 1.
Next, the first oil-in-water emulsion was passed through a homogenizing machine (manufactured by Sanmaru Kikai Kogyo Co., Ltd.), preheated to 70 ° C., and then homogenized under a pressure of 9.0 MPa. Then, after sterilizing by heating at 80 ° C., the mixture was cooled to 5 ° C. and stored in an aging tank.
Then, according to the composition of the protein-containing raw material in Table 1, skim milk powder, modified starch, and trisodium citrate were dissolved in water to prepare a protein-containing raw material. This protein-containing raw material was batch sterilized to a temperature of 80 ° C., cooled to about 5 ° C., and added to an aging tank for storing a homogenized first oil-in-water emulsion. The first oil-in-water emulsion and the protein-containing raw material were mixed with a stirring blade in an aging tank to obtain a second oil-in-water emulsion. The second oil-in-water emulsion was further aged in a refrigerator at 5 ° C. for 24 hours. As a result, a cream having a fat content of 35% and a protein content of 2.87% was obtained.
In Comparative Example 2, all the components blended in the protein-containing raw material were blended in the aqueous phase portion, and the same as in Example 3 except that the protein-containing raw material was not added to the homogenized first oil-in-water emulsion. A cream having an oil content of 35%, a protein content of 2.87%, and a pH of 7.0 was obtained.
The fat content and protein content are values calculated from the formulation. The pH was measured using a pH meter (HORIBA).

With respect to the obtained cream (hereinafter, also referred to as "neutral cream"), the following acid resistance test 1, foaming resistance test, acid resistance test 2 and the amount of protein precipitate were measured.

(Acid resistance test 1)
1.0 mL of a 10% citric acid solution was added to 200 g of the neutral cream, and the pH and viscosity were measured. The pH measuring method is as described above. The method for measuring the viscosity is shown below.

"viscosity"
The viscosity was measured using a B-type viscometer (TOKI) under the conditions of 30 seconds and 60 rpm. The upper limit of the viscosity measurement was 10000 mPa · s.

FIG. 6 shows the measurement results (horizontal axis: pH, vertical axis: viscosity). Table 3 shows the viscosity of the cream before the addition of the citric acid solution and the viscosity of the cream (hereinafter, also referred to as "acidic cream") having a pH of around 4.5 (isoelectric point of casein) by adding the citric acid solution. The result is shown. Further, FIG. 7 shows the viscosity of the acidic cream at a pH of around 4.5. FIG. 8 shows a scatter plot and a regression equation showing the relationship between the protein content of the first oil-in-water emulsion in each example and the viscosity of the cream (oil-in-water emulsion) near pH 4.5.
It should be noted that the cream having no acid resistance thickens when the pH is around 4.5 and cannot be whipped, or even if it can be whipped, the specific gravity of the whipped cream becomes high. On the other hand, the acid-resistant cream has a lower specific gravity of the whipped cream.

The creams of Comparative Examples 1 and 2 had a viscosity of 5810 mPa · s or more when the pH was lowered to around 4.5 and were acidic. On the other hand, the creams of Examples 1 to 3 had a viscosity of 5000 mPa · s or less when the pH was lowered to around 4.5. If the viscosity is 5000 mPa · s or less, whipping is particularly sufficient.
From the comparison of Examples 1 to 3 and Comparative Examples 1 and 2, even if the final composition is the same, the lower the protein content of the first oil-in-water emulsion, the lower the pH to around 4.5. It can be seen that the thickening was suppressed and the foaming property was good.
In particular, in Comparative Example 1, the protein content of the first oil-in-water emulsion was 1.4%, and the viscosity of the final acidic cream was 5810 mPa · s. Then, it can be said that the preferable protein content of the first oil-in-water emulsion is less than 1.4%, and the preferable viscosity range of the final acidic cream is less than 5810 mPa · s.
On the other hand, looking at FIG. 8, it is understood that the viscosity of the acidic cream in the vicinity of pH 4.5 is linear for Examples 1 to 3 and Comparative Example 1. Then, when the protein content of the first oil-in-water emulsion is 1.4%, the viscosity of the acidic cream is calculated as 5394 mPa · s from the regression equation (y = 2240.1x + 2257.4) in FIG. .. Therefore, it can be said that the preferable range of viscosity of the acidic cream is less than 5394 mPa · s from the top of the regression equation.
Further, since the protein content of the first oil-in-water emulsion having a more preferable viscosity of 5000 mPa · s is 1.2% when calculated back from the regression equation, the protein content of the first oil-in-water emulsion is contained. A more preferred range of amounts is also estimated to be 1.2% or less. Among them, 1.0% or less is preferable, the numerical value (0.8%) or less of Example 3 is more preferable, the numerical value (0.4%) or less of Example 2 is further preferable, and the vicinity of Example 1 (omitted). It can be said that (around 0%) is particularly preferable.

(Foamability test)
64 g of sugar was added to 800 g of the neutral cream to obtain a sweetened cream. The obtained sweetened cream was whipped using a mixer (Kenmix) at 180 rpm for the whipping time shown in Table 4 to obtain a whipped cream. The end point of whipping was defined as the time when the hardness of the whipped cream reached 20 ± 1 mm in terms of the degree of penetration of the Penetro needle (hereinafter, also referred to as “Penetro value”). The overrun and penetro values of the whipped cream were measured by the following measuring methods. The overrun values of the obtained whipped cream are shown in Table 4.

"overrun"
The specific gravity (ρ0) of the sweetened cream before whipped cream and the specific gravity (ρw) of the whipped cream were measured, and the overrun (OR) was calculated by the following formula.
OR (%) = (ρ0-ρw) / ρw × 100

"Penetro value (Penetro needle insertion degree)"
The Penetro value is a value (without a unit) obtained by multiplying the penetration distance (mm) of the conical cone when a specific conical cone is dropped and penetrated into the composition under predetermined conditions. The larger this value is, the softer it is.
Specifically, using a penetrometer, an aluminum conical cone having a bottom diameter of 24 mm, a height of 33.5 mm, a tip angle of 40 °, and a tip angle of 12 g is penetrated into the sample, and the penetration depth (mm) is measured. , The value obtained by multiplying the measured value by 10 was taken as the Penetro value.

Both the creams of Examples 1 to 3 and Comparative Examples 1 and 2 had foaming properties in the neutral state.

(Acid resistance test 2)
Put 400 g of the neutral cream of Example 1, Example 3 or Comparative Example 1 in a mixer (Chef Classic manufactured by Delonghi), add a 10% citric acid solution to adjust the pH to 4.5 or less, and then rotate the number. Whipped cream was obtained by whipping at 180 rpm for the whipping time shown in Table 5.
Table 5 shows the pH of the cream before whipping (after pH adjustment), the temperature at the time of whipping (at the start of whipping → at the end of whipping), the specific gravity of the whipped cream, the overrun and the penetro value.
After storing the obtained whipped cream in a refrigerator at 5 ° C. for 24 hours, the Penetro value (Penetro value after 1 day) was measured, and the difference from the Penetro value at the end of whipping (Penetro value after 1 day-whipped cream). The Penetro value at the end) (hereinafter, also referred to as "Penetro value difference after 1 day") was calculated. From the results, the condition after 1 day was evaluated according to the following criteria. The results are shown in Table 5.
X: The difference in Penetro value after 1 day is +100 or more.
Δ: The difference in Penetro value after 1 day has passed is +50 or more and less than +100.
◯: The difference in Penetro value after 1 day is -15 or more and less than +50.
Δ: The difference in Penetro value after 1 day has passed is -25 or more and less than -15.
X: The difference in Penetro value after 1 day is less than -25.
The methods for measuring pH, overrun and penetro values are as described above.

Compared with the cream of Comparative Example 1, the creams of Examples 1 and 3 were suppressed from changing in the state after the addition of an acidic material and foaming.

(Measurement of protein precipitate amount)
Example 1 (protein content of first oil-in-water emulsion 0% / protein content of cream 2.87%), Example 3 (protein content of first oil-in-water emulsion 0.8% / cream) Protein content 2.87%) and Comparative Example 1 (protein content 1.4% of the first oil-in-water emulsion / protein content 2.87% of the cream) according to the following procedure. The amount of protein precipitate was determined.
50 mL of the sample (cream) was dispensed into a centrifuge tube with a scale, and centrifuge was performed at 3000 rpm for 5 minutes using a centrifuge (Hitachi small centrifuge himac CT6E, rotor "T4SS swing type"). .. The maximum turning radius r was 16.2 cm, the rotation speed N was 3000 rpm, and the relative centrifugal acceleration was 1630 × g.
After centrifugation, the amount of protein precipitate (mL) in the centrifuge tube was visually confirmed. From this amount of precipitate (mL), the ratio (% by volume) of the volume of the precipitated protein to the total volume of the sample was determined and used as the amount of protein precipitate. The results are shown in Table 6.
Since the conditions for centrifugation in this test are harsh, it is irrelevant to the occurrence of precipitation when the sample is normally left to stand. That is, the magnitude of the amount of precipitation in this test has nothing to do with the product quality such as the length of the storage period of each sample.

As described above, in Comparative Example 1 in which the protein content of the first oil-in-water emulsion was 1.4%, the protein precipitation amount was 0%.
On the other hand, the creams of Examples 1 and 3 had a protein precipitation amount of more than 0%. Further, the smaller the protein content of the first oil-in-water emulsion, the larger the amount of protein precipitate.

<Test Example 2>
This test example was carried out in order to verify whether the same result can be obtained by adding modified starch and trisodium citrate added to the protein-containing raw materials to the aqueous phase portion in Examples 1 to 3.

The cream of Example 4 was obtained in the same manner as in Example 1 except that the compositions of the aqueous phase portion and the protein-containing raw material were changed as shown in Table 7.
The obtained cream was subjected to the above-mentioned foaming property test and acid resistance test in a neutral state. The results of the foaming resistance test are shown in Table 8, and the results of the acid resistance test are shown in FIG. The results of Example 1 are also shown in FIG.

In Example 4, the whipping time was shortened by about 1 minute and the viscosity was also lowered as compared with Example 1. The overrun was about the same. In the acid resistance test, no sharp increase in viscosity was observed even when the pH was lowered as in Example 1. From this, it is considered that the timing of adding modified starch or trisodium citrate may be before or after homogenization.

<Test Example 3>
This test example was conducted to evaluate the effect of the protein concentration of the cream on the acid resistance of the cream.

The creams of Examples 5 to 7 were obtained in the same manner as in Example 1 except that the compositions of the aqueous phase portion and the protein-containing raw material were changed as shown in Table 9. The overall composition of each cream (second oil-in-water emulsion) is shown in Table 10. In Table 10, the values of Y are 6.70 in Example 5, 8.80 in Example 6, and 14.70 in Example 7.
The obtained cream was subjected to the above-mentioned foaming property test and acid resistance test. The results of the foaming resistance test are shown in Table 11, and the results of the acid resistance test are shown in FIG. The results of Example 1 and Comparative Example 2 are also shown in FIG.

As shown in the above results, in the foaming test, the whipping time increased as the protein content of the cream increased. Also, the overrun has decreased.
In the acid resistance test, the thickening when the pH was lowered was suppressed in any of Examples 5 to 7. In particular, the results were good when the protein content of the cream was less than 5.00%, especially 3.00% or less.

<Example 8>
200 g of the cream of Example 1 and 200 g of fruit puree (Franboise, sweetened 15%, manufactured by Boiron Co., Ltd.) were mixed to obtain the cream of Example 8.
The obtained cream was whipped at a rotation speed of 180 rpm using a whipper manufactured by Delonghi (Kitchen Machine Chef Classic), and a whipped cream was obtained.
Table 12 shows the pH of the cream before whipping (after mixing the fruit puree), the temperature at the time of whipping (at the start of whipping → at the end of whipping), the whipping time, the specific weight of the whipped cream, the overrun and the Penetro value (the degree of penetration of the Penetro needle). Shown in.
The obtained whipped cream was stored in a refrigerator at 5 ° C. for 24 hours, and then the Penetro value (Penetro value after 1 day) was measured, and the difference in Penetro value after 1 day was calculated. The results were evaluated in the same manner as in the acid resistance test 2. The results are shown in Table 12.
The methods for measuring pH, overrun and penetro values are as described above.

The cream of Example 8 suppressed the change in the state after foaming as compared with the cream of Comparative Example 1.

In the present invention as described above, the protein content of the first oil-in-water emulsion may be 0% or may be in the range of more than 0% and less than 1.4% by mass.
The present invention can also be expressed as follows.
[A] A method for producing an oil-in-water emulsion composed of a protein source, fats and oils, water, and other raw materials, in which all of the fats and oils, a part of water, and a part of other raw materials are mixed and homogenized. The step of sterilizing to prepare a first oil-in-water emulsion, the step of mixing and sterilizing the rest of water, the rest of other raw materials, and the protein source to prepare a protein-containing raw material, and the first step. A method for producing an oil-in-water emulsion, which comprises a step of mixing the protein-containing raw material with the oil-in-water emulsion to prepare a second oil-in-water emulsion.
[B] A method for producing an oil-in-water emulsion composed of a protein source, fats and oils, water, and other raw materials, wherein all of the fats and oils, a part of water, a part of other raw materials, and a part of a protein source are used. The step of mixing, homogenizing and sterilizing to prepare a first oil-in-water emulsion having a protein content of more than 0% by mass and less than 1.4% by mass, the balance of water, the balance of other raw materials, And a step of mixing and sterilizing the rest of the protein source to prepare a protein-containing raw material, and a step of mixing the protein-containing raw material with the first oil-in-water emulsion to prepare a second oil-in-water emulsion. A method for producing an oil-in-water emulsion, including.

Claims (10)

A step of homogenizing a first oil-in-water emulsion containing fat and water and having a protein content of less than 1.4% by mass to obtain a homogenized first oil-in-water emulsion. ,
A method for producing an oil-in-water emulsion, which comprises a step of mixing the homogenized first oil-in-water emulsion and a protein-containing raw material to obtain a second oil-in-water emulsion. The method for producing an oil-in-water emulsion according to claim 1, wherein the second oil-in-water emulsion is not homogenized after the step of obtaining the oil-in-water emulsion. The method for producing an oil-in-water emulsion according to claim 1 or 2, wherein the oil-in-water emulsion content of the first oil-in-water emulsion is 1 to 60% by mass. The method for producing an oil-in-water emulsion according to any one of claims 1 to 3, wherein the protein content of the second oil-in-water emulsion is 0.4% by mass or more and less than 5% by mass. The pH of the oil-in-water emulsion produced by the above-mentioned production method is 6.5 to 7.5, the viscosity at 10 ° C. is 1 to 1000 mPa · s, and the pH of the oil-in-water emulsion is 4.5. The method for producing an oil-in-water emulsion according to any one of claims 1 to 4, wherein the viscosity at 10 ° C. is less than 5810 mPa · s when the temperature is in the vicinity. A method for producing a bubble-containing oil-in-water emulsion, wherein the oil-in-water emulsion produced by the production method according to any one of claims 1 to 5 is foamed to form a bubble-containing oil-in-water emulsion. A method for producing a frozen bubble-containing oil-in-water emulsion, wherein the bubble-containing oil-in-water emulsion produced by the production method according to claim 6 is frozen to form a frozen bubble-containing oil-in-water emulsion. An acidic oil-in-water emulsion is added to an oil-in-water emulsion produced by the production method according to any one of claims 1 to 5, and the pH is adjusted to the range of 3.0 to 6.5. A method for producing an acidic oil-in-water emulsion, which is an emulsion. A method for producing a bubble-containing acidic oil-in-water emulsion, wherein the acidic oil-in-water emulsion produced by the production method according to claim 8 is foamed to form a bubble-containing acidic oil-in-water emulsion. An oil-in-water emulsion containing fats and oils, water and proteins.
The pH is 6.5-7.5 and
The viscosity at 10 ° C. is 1 to 1000 mPa · s, and the viscosity is 1 to 1000 mPa · s.
The viscosity of the oil-in-water emulsion at 10 ° C. when the pH was around 4.5 was less than 5810 mPa · s.
An oil-in-water emulsion in which the amount of protein precipitate measured by the following measuring method exceeds 0% by volume.
Method for measuring the amount of protein precipitate: 50 mL of the oil-in-water emulsion was placed in a centrifuge tube with a scale, and the mixture was centrifuged at a relative centrifugal acceleration of 1630 × g for 5 minutes using a centrifuge. The volume (mL) of the protein precipitated in the centrifuge tube is visually measured, and the ratio (% by volume) of the volume of the protein to the total volume of the oil-in-water emulsion is defined as the amount of protein precipitate.

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