Milk protein concentrate and method for producing the same

Abstract

Milk protein concentrates containing MP whey will precipitate if left standing. Similarly, liquid products or liquid food ingredients containing MP whey also have the problem of their components settling if left standing. [Solution] The above problem can be solved by a milk protein concentrate containing MP whey, which has a solid content concentration of less than 19% by weight, a protein content of less than 60% by weight in the solid content, and an insoluble whey protein ratio of 70% or more. This milk protein concentrate has the property of being less prone to precipitation. Therefore, by using this milk protein concentrate instead of conventional MP whey material in the production of food products, precipitation in the raw materials and food products during the production process can be reduced, thereby solving the above problem.

Description

Technical Field

[0001] The present invention relates to a milk protein concentrate and a method for producing the same. In particular, the present invention relates to a milk protein concentrate containing MP whey and a method for producing the same, as well as a food product containing the milk protein concentrate containing MP whey and a method for producing the same.

Background Art

[0002] Whey, which is a by-product generated when producing cheese or casein from animal milk such as cow milk, is rich in whey protein that is a milk protein. Whey protein is known as a high-quality protein source, and conventionally, WPC (Whey Protein Concentrate) and WPI (Whey Protein Isolate) with an increased whey protein concentration and reduced lactose and mineral concentrations have been produced and sold as whey protein materials by concentrating whey with a UF membrane. In recent years, MP (Microparticulated) whey prepared by utilizing the property of whey protein to be denatured or aggregated by heating has been widely used in applications such as improving the yield of natural cheese, and as a fat substitute in fermented milk, dressings, ice cream and the like, and MP whey materials, production apparatuses therefor and the like are commercially available. MP whey is generally an aggregate of whey protein having a volume-based median diameter (50% particle diameter) of 0.5 to 10 μm, and precipitates by centrifugation at 5000 g to 15,000 g.

[0003] Patent Document 1 is a document relating to white mold type cheese that contains microparticulated whey and is characterized by high fluidity at normal temperature. In Examples, it is described that a microparticulated whey solution having a denaturation rate of 78.4% and a median diameter of microparticulated whey of 0.83 μm was obtained by subjecting concentrated whey containing 10% by weight of whey protein, which was obtained by concentrating defatted cheese whey from which casein fine particles had been removed with a UF membrane, to heat-shear treatment.

[0004] Patent Document 2 describes a cream cheese product characterized by containing 0.01% by weight or more of MP (MicroParticulated) whey, which suppresses syneresis during storage, has a melt-in-your-mouth texture similar to fresh natural cheese, and possesses good mixing and baking properties during cooking. The example describes how heating and shearing a WPI solution with a whey protein concentration of 10% by weight and concentrated whey yielded an MP whey solution with a volume-based median diameter of 0.43 to 8.50 μm and a degree of denaturation of 65 to 98.9%.

[0005] Patent Document 3 is a document relating to a food product containing a heat-treated liquid milk protein concentrate, and to a method for producing and using these milk protein concentrates and food products. In the method for producing the food product, it is disclosed that a heat-treated liquid milk protein concentrate is produced directly from fresh liquid milk, and that the milk protein concentrate contains at least about 9% by weight of total protein and at least about 60% by weight of total protein relative to the total non-fat solids. Patent Document 3 also states that the milk protein concentrate is prepared by subjecting the residual liquid obtained by ultrafiltration or microfiltration of fresh liquid milk to a heat treatment having an F0 value of at least 3.0, and that the milk protein does not exhibit gelation or aggregation even when stored at a temperature of about 20°C for at least about one month.

[0006] Patent Document 4 discloses that various dairy products with rich milk flavor can be produced using a milk protein concentrate as a raw material, wherein the protein content per 20% by mass of total solids is in the range of 9.0% to 15.5% by mass, the ash content is in the range of 0.20% to 1.30% by mass, and the heat coagulation time at 130°C is 8 minutes or more at a pH of 6.4 to 6.7. It also states that the milk protein concentrate is prepared by repeatedly performing pH adjustment, ultrafiltration, and water addition multiple times.

[0007] Patent documents 1 and 2 do not describe the composition of concentrated whey or WPI solution, nor do they describe the precipitation of MP whey solution obtained by heating and shearing treatment. Patent document 3 does not describe the precipitation, gelation, or aggregation of milk protein concentrate at the heating temperature during sterilization. Patent document 4 does not describe the inclusion of MP whey in milk protein concentrate. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2020-145926 [Patent Document 2] Japanese Patent Publication No. 2023-49670 [Patent Document 3] Special table 2022-529440 publication [Patent Document 4] Japanese Patent Publication No. 2022-31425 [Overview of the project] [Problems that the invention aims to solve]

[0009] Milk protein concentrates containing MP whey will precipitate if left standing. Similarly, liquid products or liquid food ingredients containing MP whey also have the problem of their components settling if left standing. [Means for solving the problem]

[0010] The inventors, through diligent research, have found that precipitation is less likely to occur in milk protein concentrates when the proportion of insoluble whey protein is high. This contradicts the inventors' expectation that precipitation is more likely to occur in milk protein concentrates when the proportion of insoluble whey protein is high. Furthermore, the inventors, through further diligent research, have found that precipitation is less likely to occur when the 50% particle size of MP whey in the milk protein concentrate is small. In other words, the present invention includes the following configuration. [1] A milk protein concentrate containing MP whey, having a solids content of less than 19% by weight, a protein content of less than 60% by weight in the solids, and an insoluble whey protein ratio of 70% or more. [2] A milk protein concentrate containing MP whey as described in [1], wherein 50% of the MP whey has a particle size of 4 μm or less. [3] MP whey prepared by heating and shearing a whey solution having a solid content concentration of less than 19% by weight and a protein content of less than 60% by weight in the solid content, under conditions such that the insoluble whey protein ratio is 70% or more. [4] MP whey as described in [3], wherein 50% of the particles have a diameter of 4 μm or less. [5] A method for producing a milk protein concentrate containing MP whey, comprising the steps of: preparing a whey solution having a solid content concentration of less than 19% by weight and a protein content of less than 60% by weight in the solid content; and heating and shearing the whey solution under conditions such that the insoluble whey protein ratio is 70% or more. [6] The method for producing a milk protein concentrate containing MP whey according to [5], wherein the conditions for the insoluble whey protein ratio to be 70% or more are such that the insoluble whey protein ratio is 70% by weight or more and the 50% particle size of MP whey is 4 μm or less. [7] A method for producing a milk protein concentrate containing MP whey according to [5], wherein the conditions for the insoluble whey protein ratio to be 70% or more are a heating temperature of 70°C or more and 95°C or less and a heating holding time of 100 seconds or more and 900 seconds or less. [8] A method for producing a milk protein concentrate containing MP whey according to any one of items [5] to [7], wherein the peripheral shear speed is 4 m / s or more. A food product containing milk protein concentrate, including MP whey as described in [9][1]. A food product containing MP whey as described in

[10] [3].

[11] The food described in [9] or

[10] , wherein the MP whey content is 0.01% by weight or more.

[12] A food product of milk or dairy products as described in [9] or

[10] .

[13] Foods as described in [9] or

[10] , selected from beverages, desserts, cheeses, creams, fermented milks, ice creams, frozen desserts, and dressings. A method for producing food, comprising the step of preparing ingredients for a food containing a milk protein concentrate containing MP whey as described in

[14] [1]. A method for producing food, comprising the step of preparing the raw materials for a food containing MP whey as described in

[15] [3].

[16] A method for producing the food according to

[14] or

[15] , wherein the MP whey content in the food is 0.01% by weight or more.

[17] A method for producing the food according to

[14] or

[15] , wherein the food is milk or a dairy product.

[18] A method for producing the food according to

[14] or

[15] , wherein the food is selected from beverages, desserts, cheeses, creams, fermented milk, ice creams, frozen desserts, and dressings. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a milk protein concentrate containing MP whey that is less prone to precipitation, and a method for producing the same. Furthermore, by using the milk protein concentrate containing MP whey of the present invention instead of conventional MP whey materials in the production of food products, precipitation in the raw materials and food products during the production process can be reduced. [Modes for carrying out the invention]

[0012] The present invention will be described in further detail below.

[0013] In this specification, MP whey refers to agglutinous aggregate of whey protein with a 50% volume particle size (median diameter) of 0.5 to 10 μm, which does not precipitate upon short-term standing but precipitates upon centrifugation of 5,000 g to 15,000 g. In this specification, aggregated whey refers to whey protein that is produced by heating and precipitates within a short time, about one hour, upon standing.

[0014] (Milk protein concentrate) The milk protein concentrate of the present invention comprises MP whey, has a solid content concentration of less than 19% by weight, a protein proportion in the solid content of less than 60% by weight, and an insoluble whey protein ratio of 70% or more. The milk protein concentrate of the present invention has the property of being less likely to precipitate upon standing. The milk protein concentrate of the present invention does not contain aggregated whey.

[0015] The property of the milk protein concentrate being less likely to precipitate can be confirmed, for example, by the 50% particle diameter of MP whey, the solid content concentration, and the rate of change of whey protein content when the milk protein concentrate is allowed to stand for 120 hours.

[0016] The solid content concentration of the milk protein concentrate of the present invention is preferably 6.4% by weight or more and less than 19% by weight, more preferably 6.4% by weight or more and less than 17% by weight, and even more preferably 6.4% by weight or more and less than 15% by weight. The solid content concentration can be determined by a known method such as a heat drying method or a near-infrared spectroscopy method. The proportion of protein in the solid content of the milk protein concentrate of the present invention is preferably 9.4% by weight or more and less than 60% by weight, more preferably 9.4% by weight or more and less than 55% by weight, and even more preferably 9.4% by weight or more and less than 50% by weight. The protein content can be determined by a known method such as the nitrogen combustion method. The proportion of whey protein in the protein of the milk protein concentrate of the present invention is preferably 90% by weight or more, more preferably 93% by weight or more, and even more preferably 96% by weight or more. The proportion of whey protein in the protein can be determined, for example, by the method described in "Bordin, et al. (2001) Identification and quantification of major bovine milk proteins by liquid chromatography., Journal of Chromatography A., 928, 63-76". The insoluble whey protein ratio of the milk protein concentrate of the present invention is preferably 70% or more, and more preferably 75% or more.

[0017] (Insoluble whey protein ratio) The insoluble whey protein ratio refers to the ratio of insoluble whey protein to the total amount of whey protein in a milk protein concentrate. Insoluble whey protein is whey protein that is not dissolved in the milk protein concentrate. The milk protein concentrate of the present invention contains MP whey as insoluble whey protein, but does not contain precipitate (aggregated whey) that forms in a short time, such as one hour.

[0018] The insoluble whey protein ratio of the milk protein concentrate of the present invention can be determined, for example, by the following method. Allow the milk protein concentrate to stand at 5°C for one hour and confirm that no precipitate of agglutinated whey occurs. If precipitate of agglutinated whey occurs, remove it. Next, dispense 1.6 mL of the milk protein concentrate or residue into a microcentrifuge tube and centrifuge at 15,000 g for 20 minutes. Consider the amount of whey protein contained in the supernatant as the amount of soluble whey protein, and consider the amount of protein contained in the milk protein concentrate before standing at 5°C for one hour as the total amount of whey protein. The ratio of insoluble whey protein is then calculated using the following formula. Insoluble whey protein ratio (%) = (1 - (amount of whey protein in supernatant / total amount of whey protein)) × 100 Protein quantification can be performed using methods such as nitrogen combustion.

[0019] The 50% particle size of the MP whey contained in the milk protein concentrate of the present invention is preferably 4 μm or less, more preferably 3 μm or less, even more preferably 2.2 μm or less, and still more preferably 2.0 μm or less. The lower limit is not particularly limited, but for example, it is 0.5 μm or more.

[0020] (50% particle size) The 50% particle size refers to the particle size (μm) corresponding to 50% of the integrated distribution curve based on volume. The 50% particle size (μm) of MP whey can be measured using particle size distribution measuring devices such as laser diffraction particle size analyzers, laser diffraction / scattering particle size analyzers, image analysis particle size analyzers, precision particle size analyzers, real-time zeta potential / nanoparticle size analyzers, dynamic light scattering (DLS) particle size analyzers, and analytical ultracentrifuge systems.

[0021] The form of the milk protein concentrate of the present invention is not particularly limited, but may be liquid, paste, powder, etc.

[0022] The method for producing the milk protein concentrate of the present invention will be described in detail below.

[0023] The milk protein concentrate of the present invention can be produced by a manufacturing method comprising the steps of: preparing a whey solution having a solid content concentration of less than 19% by weight and a protein content of less than 60% by weight in the solid content; and heating and shearing the whey solution under conditions such that the insoluble whey protein ratio is 70% or more.

[0024] (Whey solution) The whey solution used in the method for producing milk protein concentrate of the present invention can be obtained through a process of removing fat and casein fines from whey, a by-product of producing natural cheese and casein, and a process of concentrating whey protein while removing ash and lactose using a membrane or ion exchange resin. Examples of processing membranes that can be used include, but are not limited to, ultrafiltration membranes with a fractional molecular weight cutoff of 10,000 Da or less. The whey solution used in the method for producing milk protein concentrate of the present invention can be obtained through the above-described process, but may also be obtained by reducing WPC or WPI in a solvent such as water. The proportion of whey protein in the whey solution is preferably 90% by weight or more, more preferably 93% by weight or more, and even more preferably 96% by weight or more. Furthermore, the whey protein content in the whey solution is preferably 3.0% by weight or more and 20.0% by weight or less, more preferably 5.0% by weight or more and 17.0% by weight or less, and even more preferably 7.0% by weight or more and 14.0% by weight or less.

[0025] (Heating and shearing) The heating and shearing conditions for the whey solution are not particularly limited as long as the insoluble whey protein ratio is 70% or more, but preferably the conditions are such that the insoluble whey protein ratio is 70% or more and the 50% particle size of MP whey is 4 μm or less. The heating temperature and holding time for the heating and shearing treatment are preferably 70°C or higher and less than 95°C and a holding time of 100 seconds or higher and 900 seconds or less, more preferably 75°C or higher and less than 95°C and a holding time of 300 seconds or higher and 900 seconds or less, and even more preferably 85°C or higher and less than 95°C and a holding time of 500 seconds or higher and 900 seconds or less. The peripheral speed of shearing in the heating and shearing treatment is preferably 4 m / s or higher, more preferably 6 m / s or higher, even more preferably 10 m / s or higher, and even more preferably 15 m / s or higher.

[0026] For equipment used to heat and shear the whey solution, equipment capable of simultaneously performing heating and shearing is desirable, such as a scraping-type sterilizer. Shearing can also be performed using a high-pressure homogenizer or the like.

[0027] The MP whey of the present invention is formed from whey protein by heating and shearing the above-described predetermined whey solution under predetermined conditions. The 50% particle size of the MP whey of the present invention is preferably 4 μm or less, more preferably 3 μm or less, even more preferably 2.2 μm or less, and even more preferably 2.0 μm or less. The lower limit is not particularly limited, but for example, it is 0.5 μm or more. The MP whey of the present invention, like the milk protein of the present invention, has the property of not easily settling upon standing.

[0028] Depending on the heating and shearing conditions applied to the whey solution, aggregated whey may be produced along with MP whey. As described above, aggregated whey settles after a short period of standing, about one hour, whereas the MP whey of the present invention does not settle after a short period of standing. Therefore, even if aggregated whey is produced by heating and shearing the whey solution, the milk protein concentrate of the present invention can be obtained by separating it from the aggregated whey by letting the milk protein concentrate stand for about one hour and removing the settled aggregated whey. Furthermore, the MP whey of the present invention can be obtained by further separating it from the aggregated whey by centrifuging the milk protein concentrate at a concentration of 5,000 g to 15,000 g.

[0029] The liquid milk protein concentrate produced by the manufacturing method of the present invention may be further concentrated by methods such as microfiltration, ultrafiltration, ion exchange, or centrifugation. Furthermore, the liquid milk protein concentrate produced by the manufacturing method of the present invention can be powdered by spray drying or freeze-drying. When powdering the milk protein concentrate by spray drying, although not particularly limited, it can be done by spraying the liquid milk protein composition with a spray dryer and drying it with hot air.

[0030] The milk protein concentrate or MP whey of the present invention has properties that make it less prone to precipitation. By using the milk protein concentrate or MP whey of the present invention instead of conventional MP whey materials in the production of food products, the occurrence of precipitation in the raw materials or food products during the production process can be reduced.

[0031] In food manufacturing, the liquid milk protein concentrate obtained by heating and shearing the whey solution may be used as is, or the liquid milk protein concentrate or MP whey separated therefrom may be processed into powder, liquid, paste, or other forms as appropriate.

[0032] In food manufacturing, methods for preparing food ingredients containing milk protein concentrate or MP whey include, for example, adding the milk protein concentrate or MP whey to the food ingredients, adding it to a mixture of food ingredients during the manufacturing process, or adding it when food manufacturing is nearly complete. Alternatively, food materials containing milk protein concentrate or MP whey may be prepared in advance as food ingredients.

[0033] The MP whey content in the food is preferably 0.01% by weight or more, more preferably 0.1% by weight or more, and even more preferably 1.0% by weight or more. [Examples]

[0034] The following describes in detail some embodiments of the present invention, but the present invention is not limited to these embodiments, and various improvements based on known methods can be made.

[0035] (Examples 1 and 2, Comparative Examples 1 and 2) Cheese whey was processed using a milk clarifier at a rate of 6,500 g to remove casein particles, and then degreased using an MF membrane (0.8 μm pore size). It was pasteurized at 70°C and immediately cooled. A whey solution was prepared by concentrating it 20-fold at 10°C using a UF membrane apparatus. The whey solution had a solid content of 18.0% by weight, a protein content of 55.5% by weight in the solids, a whey protein content of 100.0% by weight in the protein, and a whey protein content of 10.0% by weight. The whey solution was heated and sheared under the conditions described in Table 1 to obtain milk protein concentrates containing MP whey for Examples 1 and 2 and Comparative Examples 1 and 2. Furthermore, the milk protein concentrates for Examples 1 and 2 and Comparative Examples 1 and 2 did not contain aggregated whey that occurs when left standing at 5°C for one hour.

[0036] (50% particle size) The 50% particle size of MP whey in the milk protein concentrates of Examples 1 and 2 and Comparative Examples 1 and 2 was measured using a SALD-2300 (Shimadzu Corporation). A flow cell was used, with a measurement absorbance range of 0.01 to 0.2, a sample refractive index of 1.65 to 0.01i, a measurement interval of 30 seconds, two measurements, a pump speed of 5, and a target particle size of 0.017 to 2500 μm. The particle size corresponding to 50% of the obtained volume-based integrated distribution curve was defined as the 50% particle size (μm) of MP whey.

[0037] (solid content concentration) The solid content concentration in the milk protein concentrates of Examples 1 and 2 and Comparative Examples 1 and 2 was measured using Smart Turbo (CEM).

[0038] (Whey protein content) The whey protein content in the milk protein concentrates of Examples 1 and 2 and Comparative Examples 1 and 2 was determined by nitrogen combustion.

[0039] (Insoluble whey protein ratio) The insoluble whey protein ratios of Example 1 and 2 and Comparative Example 1 and 2 were determined by the following method. The milk protein concentrates of Examples 1 and 2 and Comparative Examples 1 and 2 were allowed to stand at 5°C for one hour, and no precipitation (agglutinated whey) was observed. 1.6 mL of the milk protein concentrate was dispensed into a microcentrifuge tube and centrifuged at 15,000 g for 20 minutes. The amount of whey protein contained in the supernatant was considered to be the amount of soluble whey protein, and the amount of protein contained in the milk protein concentrate was considered to be the total amount of whey protein. The ratio of insoluble whey protein was then calculated using the following formula. Insoluble whey protein ratio (%) = (1 - (amount of whey protein in supernatant / total amount of whey protein)) × 100 Protein quantification was performed using the nitrogen combustion method.

[0040] (Percentage change in 50% particle size, solid content concentration, and whey protein content) The percentage changes in 50% particle size, solid content concentration, and whey protein content were calculated using the following method. After stirring Examples 1 and 2 and Comparative Examples 1 and 2, a fixed amount was withdrawn from each, and the 50% particle size, solid content concentration, and whey protein content were measured and recorded as the values ​​before standing. 15 mL of each stirred Example 1 and 2 and Comparative Examples 1 and 2 were added to a 20 mL graduated cylinder, and after standing at 5°C for 120 hours, 5 mL each was withdrawn from the upper and lower layers using a pipette, and the 50% particle size, solid content concentration, and whey protein content of the upper and lower layers were measured and recorded as the values ​​after standing. The percentage change in 50% particle size, solid content concentration, and whey protein content was calculated from the values ​​before and after standing using the following formula. Rate of change (%) = (|Value before standing - Value after standing| / Value before standing) × 100

[0041] [Table 1]

[0042] Table 1 shows the 50% particle size, solid content concentration, whey protein content, and insoluble whey protein ratio of MP whey for Example 1 and 2 and Comparative Example 1 and 2 before standing. Milk protein concentrates obtained by shearing a whey solution at a heating temperature of 85°C for 300 seconds had an insoluble whey protein ratio of 70% or more (Examples 1 and 2). Milk protein concentrates obtained by shearing a whey solution at a heating temperature of 85°C for 0 seconds had an insoluble whey protein ratio of less than 70% (Comparative Examples 1 and 2). In addition, increasing the peripheral speed of shearing reduced the 50% particle size of MP whey.

[0043] [Table 2]

[0044] Table 2 shows the 50% particle size, solid content concentration, and whey protein content of MP whey for Examples 1 and 2 and Comparative Examples 1 and 2 after standing for 120 hours.

[0045] [Table 3]

[0046] Table 3 shows the results for the 50% particle size, solid content concentration, and percentage change in whey protein content of MP whey for Examples 1 and 2 and Comparative Examples 1 and 2. Smaller values ​​for the percentage change in solid content concentration and whey protein content of the upper and lower layers indicate reduced precipitation. Milk protein concentrates with an insoluble whey protein ratio of 76.1% and 75.1% showed smaller changes in 50% particle size, solid content concentration, and whey protein content of the upper and lower layers compared to milk protein concentrates with an insoluble whey protein ratio of 62.0% and 61.7% (Examples 1 and 2 and Comparative Examples 1 and 2). This indicates that milk protein concentrates containing MP whey are less prone to precipitation when the insoluble whey protein ratio is higher. Furthermore, at similar insoluble whey protein ratios, the milk protein concentrate with 50% smaller MP whey particles showed smaller changes in 50% particle size, solid content concentration, and whey protein content in the upper and lower layers of the liquid (comparison of Example 1 and Example 2, and comparison of Comparative Example 1 and Comparative Example 2). From this, it was found that milk protein concentrates containing MP whey are less prone to precipitation when the 50% particle size of MP whey is smaller.

[0047] The following describes food products manufactured using the milk protein concentrate containing MP whey of the present invention. The present invention is not limited to the following description.

[0048] (Test Example 1) The static fermented milk of Test Example 1 was produced by the following preparation method. The mixed ingredients consisted of 10.0% skim milk powder, 3.5% MPC, 1% milk protein concentrate containing MP whey, and 85.5% prepared water. The MP whey concentration in the mixed ingredients was 0.06% by weight. The mixed ingredients were heated to 65°C, then mixed and dissolved in a homomixer to prepare the mix. The mix was reheated to 65°C and heated to 140 kg / cm³. 2 After homogenization at a homogenization pressure, the mixture was heat-sterilized at 95°C for 300 seconds. No coagulation occurred during sterilization. The mixture was then cooled to 40°C, and 1.5% by weight of Lactobacillus bulgaricus and 0.15% by weight of Streptococcus thermophilus were added, and the mixture was filled into plastic cup containers. The containers filled with the mix were fermented in a fermentation chamber set at 40°C, and when the acidity reached 1.00%, it was cooled to 5°C to obtain static fermented milk. No precipitate was found in the prepared fermented milk.

[0049] (Test Example 2) Camembert cheese for Test Example 2 was produced using the following preparation method. A milk protein concentrate containing MP whey was added to the raw milk at a concentration of 2% by weight, followed by pasteurization (75°C for 15 seconds). No coagulation occurred during pasteurization. At this time, the MP whey concentration in the pasteurized milk was 0.12% by weight. 0.01% by weight calcium chloride and bulk starter were added, and fermentation was carried out to pH 6.4. 0.0015% by weight rennet powder was added, and after 30 minutes, the curd was cut into 30mm squares. The curd was poured into a mold, curd formation and whey removal were performed, and then it was placed in a maturation room (room temperature 20°C, humidity 80% or higher). The following day, salt was added and white mold inoculation was performed. On the 6th day of production, the Camembert cheese was film-wrapped, and maturation continued at 10°C thereafter. It was confirmed that a substantial amount of the MP whey added to the prepared Camembert cheese was uniformly incorporated into the cheese.

[0050] (Test Example 3) The beverage in Test Example 3 was prepared using the following preparation method. A mixture of 70.0% raw milk, 0.5% skim milk powder, 1.1% cream, 4.0% sugar, 1.6% coffee (coffee extract), 0.1% sodium bicarbonate, 3.0% milk protein concentrate containing MP whey, and 25.4% prepared water was prepared. The MP whey concentration in this solution was 0.18% by weight. This solution was homogenized at 15 MPa in a homogenizer and then sterilized at 90°C. No coagulation occurred during sterilization. After filling into plastic pouches, the pouches were immersed in ice water and cooled to below 10°C to obtain the beverage. The beverage stored at 10°C for 14 days had a wet sedimentation rate of 0.370% and a dry sedimentation rate of 0.112%, indicating almost no precipitation. On the other hand, when skim milk powder was added to achieve the same solid content concentration as the milk protein concentrate containing MP whey, the wet precipitation rate was 0.120% and the dry precipitation rate was 0.027%, indicating that almost no precipitation occurred.

[0051] (Test example 4) The static fermented milk of Test Example 4 was produced using the following preparation method. The mixed ingredients consisted of 9.0% skim milk powder, 5.5% MPC, 15.0% milk protein concentrate containing MP whey, and 70.5% prepared water. The MP whey concentration in the mixed ingredients was 0.9% by weight. The mixed ingredients were heated to 65°C, then mixed and dissolved in a homomixer to prepare the mix. The mix was reheated to 65°C and heated to 140 kg / cm³. 2 After homogenization at a homogenization pressure, the mixture was heat-sterilized at 90°C for 300 seconds. No coagulation occurred during sterilization. The mixture was then cooled to 40°C, and 1.5% by weight of Lactobacillus bulgaricus and 0.15% by weight of Streptococcus thermophilus were added, and the mixture was filled into plastic cup containers. The containers filled with the mix were fermented in a fermentation chamber set at 40°C, and when the acidity reached 1.00%, it was cooled to 5°C to obtain static fermented milk. No precipitate was found in the prepared fermented milk.

[0052] (Measurement of sedimentation rate in the product) The wet and dry sedimentation rates for Test Example 3 were determined by the following method. 40 g of sample was dispensed into a 50 mL centrifuge tube and allowed to stand at 10°C for 14 days. After standing, the supernatant was discarded by decanting, the container was inverted for 10 minutes, and the liquid adhering to the walls above 1 cm from the bottom was wiped off with a Kimwipe (Kimberly-Clark). The weight of the centrifuge tube was then measured. The weight obtained by subtracting the weight of the centrifuge tube before dispensing the sample from this weight was defined as precipitate weight 1. Subsequently, the centrifuge tube was dried at room temperature for at least 2 days, and its weight was measured. The weight obtained by subtracting the weight of the centrifuge tube before dispensing the sample from this weight was defined as precipitate weight 2. The ratio of precipitate weight 1 to the weight of the sample dispensed into the centrifuge tube was defined as the wet sedimentation rate, and the ratio of precipitate weight 2 to the weight of the sample dispensed into the centrifuge tube was defined as the dry sedimentation rate. The number of evaluations was n=2.

[0053] In the Camembert cheese of Test Example 2, the MP whey added to the raw milk was almost entirely incorporated uniformly into the cheese by the use of the milk protein concentrate containing MP whey according to the present invention. This indicates that no MP whey precipitation occurred in the raw milk to which MP whey was added.

[0054] To confirm that the MP whey added to the raw milk was almost entirely incorporated uniformly into the cheese, the amount of MP whey per 10g of Camembert was quantified as described below. For five randomly selected Camembert cheeses, 40 mL of 0.5 M sodium citrate solution and 40 mL of 50-60°C warm water were added to 10 g of the cheese. The mixture was stirred with a homomixer to solubilize the casein protein. The resulting solution was centrifuged at 15,000 g for 20 minutes, and the supernatant was discarded. 0.1 M sodium citrate solution was added to the resulting precipitate, and the precipitate was suspended. Further centrifuged at 15,000 g for 20 minutes, the supernatant was discarded, and the precipitate was obtained. The precipitate was then freeze-dried, and the insoluble whey protein fraction in the resulting powder was quantitatively analyzed using SDS-PAGE, liquid chromatography, etc. The mass (mg) of the insoluble protein fraction in the powder obtained by freeze-drying the precipitate was defined as the "MP whey amount per 10 g of Camembert." Five randomly selected Camembert cheeses each contained more than 80 mg of MP whey per 10 g of cheese. This indicates that the MP whey was uniformly incorporated into the Camembert.

Claims

1. A milk protein concentrate containing MP whey, having a solid content concentration of less than 19% by weight, a protein content of less than 60% by weight in the solid content, and an insoluble whey protein ratio of 70% or more.

2. A milk protein concentrate containing MP whey according to claim 1, wherein 50% of the MP whey has a particle size of 4 μm or less.

3. MP whey is prepared by heating and shearing a whey solution having a solid content concentration of less than 19% by weight and a protein content of less than 60% by weight in the solid content, under conditions that result in an insoluble whey protein ratio of 70% or more.

4. MP whey according to claim 3, wherein 50% of the particles have a diameter of 4 μm or less.

5. A method for producing a milk protein concentrate containing MP whey, A step of preparing a whey solution in which the solid content concentration is less than 19% by weight and the proportion of protein in the solid content is less than 60% by weight, The process includes heating and shearing the whey solution under conditions such that the insoluble whey protein ratio is 70% or more. A method for producing a milk protein concentrate containing MP whey.

6. The method for producing a milk protein concentrate containing MP whey according to claim 5, wherein the conditions for the insoluble whey protein ratio to be 70% or more are such that the insoluble whey protein ratio is 70% by weight or more and the 50% particle size of MP whey is 4 μm or less.

7. A method for producing a milk protein concentrate containing MP whey according to claim 5, wherein the conditions for the insoluble whey protein ratio to be 70% or more are a heating temperature of 70°C or more and 95°C or less and a heating holding time of 100 seconds or more and 900 seconds or less.

8. A method for producing a milk protein concentrate containing MP whey according to any one of claims 5 to 7, wherein the peripheral shear speed is 4 m / s or more.

9. A food containing a milk protein concentrate containing MP whey as described in claim 1.

10. A food containing MP whey as described in claim 3.

11. The food according to claim 9 or 10, wherein the MP whey content is 0.01% by weight or more.

12. The food according to claim 9 or 10, which is milk or a dairy product.

13. A food product according to claim 9 or 10, selected from beverages, desserts, cheeses, creams, fermented milk, ice creams, frozen desserts, and dressings.

14. A method for producing food, comprising the step of preparing raw materials for a food containing a milk protein concentrate containing MP whey as described in claim 1.

15. A method for producing food, comprising the step of preparing the raw materials for a food containing MP whey as described in claim 3.

16. A method for producing food according to claim 14 or 15, wherein the MP whey content in the food is 0.01% by weight or more.

17. The method for producing the food according to claim 14 or 15, wherein the food is milk or a dairy product.

18. A method for producing the food according to claim 14 or 15, wherein the food is selected from beverages, desserts, cheeses, creams, fermented milk, ice creams, frozen desserts, and dressings.

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