Method for producing protein-rich milk ingredient

Abstract

To provide a method for producing a protein-rich milk ingredient with a pleasant flavor.SOLUTION: The protein-rich liquid milk ingredient of the present invention can be produced by preparing a milk fluid from a milk raw material and then concentrating this milk fluid using a nano-filtration membrane.SELECTED DRAWING: None

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority to Japanese Patent Application No. 2018-202203, filed on October 26, 2018, the entire disclosure of which is incorporated herein by reference. [Technical field]

[0002] The present invention relates to a novel method for producing dairy raw materials, more particularly to a method for producing dairy raw materials comprising a step of concentrating a high-protein dairy fluid using a nanofiltration membrane. [Background technology]

[0003] In protein-containing foods, when high-protein dairy ingredients are mixed in high concentrations with raw milk, the flavor may deteriorate. It has been known that the odor specific to proteins can be reduced by adding starch with a phosphate cross-linking structure to protein-containing foods (see Patent Document 1), but it has been necessary to add a specific substance to reduce the odor specific to proteins.

[0004] In addition, it has been known that butter containing a large amount of non-fat milk solids and having excellent flavor can be produced by processing raw milk by diafiltration using a nanofiltration membrane (see Patent Document 2), but it is not known that a specific flavor can be reduced in high-protein milk raw materials by processing with a nanofiltration membrane. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-55710 A [Patent Document 2] WO2012 / 176719 Summary of the Invention

[0006] The inventors have discovered that when a high-protein milk fluid is concentrated using a nanofiltration membrane to produce a high-protein dairy raw material, the dairy raw material has an improved refreshing feeling, a reduced protein odor, and a reduced reduction odor.

[0007] According to the present invention, a high-protein dairy raw material having improved refreshing feeling and good flavor can be provided. Also, according to the present invention, a high-protein dairy raw material having reduced protein odor and good flavor can be provided. Also, according to the present invention, a high-protein dairy raw material having reduced reduction odor and good flavor can be provided.

[0008] According to the present invention, the following inventions are provided. [1] A process for preparing a high-protein milk fluid having a protein content of 60% by mass or more in the total solid content from a milk raw material; and concentrating the dairy fluid with a nanofiltration membrane; A method for producing liquid, high-protein dairy ingredients. [2] A method for producing a dairy raw material described in [1], wherein the dairy raw material used to prepare the high-protein dairy fluid has a protein content of 60 mass% or more in the total solids. [3] A method for producing a dairy raw material described in [1] or [2], in which the concentration ratio of the retentate when concentrating a high-protein dairy fluid using a nanofiltration membrane is 1.1 times or more in terms of refractive index. [4] A method for producing a dairy raw material described in any one of [1] to [3], wherein the concentration of total solids in the high-protein dairy fluid is 2 to 20 mass%. [5] A method for producing a dairy raw material described in any one of [1] to [4], wherein the protein concentration in the high-protein dairy fluid is 1.5 to 18 mass%. [6] A method for producing a dairy raw material described in any of [1] to [5], wherein the liquid high-protein dairy raw material is a liquid milk protein concentrate (MPC) or a liquid whey protein concentrate (WPC). [7] A method for producing a solid high-protein dairy raw material obtained through a drying process, comprising a step of further drying the liquid high-protein dairy raw material produced by the manufacturing method described in any one of [1] to [6]. [8] The method for producing a dairy raw material described in [7], wherein the solid high-protein dairy raw material is a solid milk protein concentrate (MPC) or a solid whey protein concentrate (WPC). [9] A method for producing a dairy raw material described in any one of [1] to [8]. When the refractive index (Brix) of the dairy raw material produced by the production method described in any one of [1] to [8] and the refractive index (Brix) of the high-protein dairy fluid are adjusted to be the same (equivalent) and the dimethyl disulfide content is measured, the dimethyl disulfide content in the dairy raw material produced by the production method described in any one of [1] to [8] changes by 20% or more compared to the dimethyl disulfide content in the high-protein dairy fluid.

[10] A method for producing a dairy ingredient according to any one of [1] to [9], wherein the dairy ingredient produced by the method for producing a dairy ingredient according to any one of [1] to [9] has an improved refreshing feeling.

[11] A method for producing a dairy raw material according to any one of [1] to

[10] , wherein the dairy raw material produced by the method for producing a dairy raw material according to any one of [1] to

[10] has a reduced protein odor.

[12] A method for improving the refreshing feeling of dairy raw materials, comprising: preparing a high-protein dairy fluid from dairy raw materials, the high-protein content of which in the total solids is 60% by mass or more; and concentrating the dairy fluid using a nanofiltration membrane to obtain a liquid high-protein dairy raw material.

[13] A high-protein milk product made from dairy ingredients, the protein content of which is 60% by mass or more in the total solids. The method for improving the refreshing feeling of a dairy raw material comprises preparing a high-quality dairy fluid, concentrating the dairy fluid using a nanofiltration membrane, and then drying the concentrated dairy fluid to obtain a solid high-protein dairy raw material.

[14] A method for reducing the protein odor of dairy raw materials, comprising preparing a high-protein dairy fluid from dairy raw materials, the high-protein fluid having a protein content of 60% by mass or more in the total solids, and concentrating the dairy fluid using a nanofiltration membrane to obtain a liquid high-protein dairy raw material.

[15] A method for reducing the protein odor of dairy raw materials, comprising: preparing a high-protein dairy fluid from dairy raw materials, the high-protein fluid having a protein content of 60% by mass or more in the total solids; concentrating the dairy fluid using a nanofiltration membrane, and then drying the concentrated dairy fluid to obtain a solid high-protein dairy raw material.

[16] A method for producing a food or beverage, comprising a step of incorporating a dairy ingredient produced by the production method described in any one of [1] to

[11] into the food or beverage.

[17] A method for producing a food or beverage described in

[16] , wherein the food or beverage is sterilized.

[18] A method for producing a food or beverage described in

[16] or

[17] , wherein the food or beverage is packaged in a container.

[19] A food or beverage comprising a dairy ingredient produced by the production method described in any one of [1] to

[11] .

[20] The food or beverage described in

[19] , which is sterilized.

[21] A food or beverage described in

[19] or

[20] that is packaged in a container.

[0009] The high-protein dairy ingredients produced by the manufacturing method of the present invention have an improved refreshing feeling, reduced protein odor, and / or reduced reduction odor, and are therefore advantageous in terms of good flavor (without worsening the flavor) even when the high-protein dairy ingredients are blended at high concentrations with raw milk in protein-containing foods and beverages. [Brief description of the drawings]

[0010] [Figure 1] The graph shows the percentage change in dimethyl disulfide in liquid MPC after concentration processing using a nanofiltration membrane (after concentration processing using a nanofiltration membrane) and in solid (powder) MPC after concentration processing using a nanofiltration membrane and then drying processing (after spray drying processing), relative to unprocessed MPC (milk protein concentrate: milk raw material with a protein content of approximately 80% by mass in the total solids content) (unprocessed milk raw material). [Diagram 2]The figure shows the percentage change in nonanal in liquid MPC (after nanofiltration membrane concentration) after concentration processing with a nanofiltration membrane, and in solid (powder) MPC (after spray drying processing) after concentration processing with a nanofiltration membrane and then drying processing, relative to unprocessed MPC (unprocessed dairy raw material). [Diagram 3] The figure shows the percentage change in pentanal in liquid MPC (after nanofiltration membrane concentration process) after concentration process with a nanofiltration membrane, and in solid (powder) MPC (after spray drying process) after concentration process with a nanofiltration membrane and then drying process, compared to unprocessed MPC (unprocessed dairy raw material). [Figure 4] The figure shows the percentage change in pentanol in liquid MPC (after nanofiltration membrane concentration process) after concentration process with a nanofiltration membrane, and in solid (powder) MPC (after spray drying process) after concentration process with a nanofiltration membrane and then drying process, compared to unprocessed MPC (unprocessed dairy raw material). [Diagram 5] This shows the percentage change in nutritional components (total solids, lipids, proteins, carbohydrates (sugars), and ash) after NF membrane treatment compared to before treatment for the reconstituted liquid (5% by weight) of MPC powder (NF membrane) (a powdered, high-protein dairy raw material). [Figure 6] This shows the percentage change in salt components (Na, K, Mg, Ca, Cl, and P) after treatment with the NF membrane compared to before treatment for the reduced liquid (5 wt%) of MPC powder (NF membrane) (a powdered high-protein dairy raw material). [Figure 7] This shows the rate of change in dimethyl disulfide after treatment with the NF membrane compared to before treatment for the reduced liquid (5 wt%) of MPC powder (NF membrane) (MPC6631) (a powdered high-protein dairy raw material). [Figure 8] The figure shows the rate of change in nonanal after treatment with the NF membrane compared to before treatment for the reconstituted liquid (5% by weight) of MPC powder (NF membrane) (MPC6631) (a powdered high-protein dairy raw material). [Figure 9] This shows the rate of change in pentanal after treatment with the NF membrane compared to before treatment for the reduced liquid (5 wt%) of MPC powder (NF membrane) (MPC6631) (a powdered high-protein dairy raw material). [Figure 10]The figure shows the rate of change in pentanol after treatment with the NF membrane compared to before treatment for the reduced liquid (5 wt%) of MPC powder (NF membrane) (MPC6631) (a powdered high-protein dairy raw material). [Figure 11] The figure shows the rate of change in aminoacetophenone after NF membrane treatment compared to before treatment for the reduced liquid (5 wt%) of MPC powder (NF membrane) (MPC6631) (a powdered high-protein dairy raw material). [Figure 12] This shows the percentage change in nutritional components (total solids, lipids, proteins, carbohydrates (sugars), ash) after NF membrane treatment compared to before treatment for the reconstituted liquid (5% by weight) of MPC (MPC6631) powder (NF membrane) (powdered high-protein dairy raw material). [Figure 13] This shows the percentage change in salt components (Na, K, Mg, Ca, Cl, and P) after treatment with the NF membrane compared to before treatment for the reduced liquid (5 wt%) of MPC (MPC6631) powder (NF membrane) (a powdered high-protein dairy raw material). Description of the Invention

[0011] [Production method of high-protein dairy ingredients] The present invention is a method for producing a liquid high-protein dairy raw material obtained by concentrating the dairy raw material with a nanofiltration membrane, comprising the steps of preparing a high-protein dairy fluid (a high-protein dairy fluid having a protein content of 60% by mass or more in the total solid content) from a dairy raw material (preferably a solid high-protein dairy raw material having a protein content of 60% by mass or more in the total solid content), and concentrating the dairy fluid with a nanofiltration membrane. In this case, the present invention is also a method for producing a liquid high-protein dairy raw material having an improved refreshing feeling and / or a good flavor. The present invention is also a method for producing a liquid high-protein dairy raw material having a reduced protein odor and / or a good flavor. The present invention is also a method for producing a liquid high-protein dairy raw material having a reduced reduction odor and / or a good flavor.

[0012] The "dairy raw material" used as the starting raw material in the production method of the present invention is a fluid such as a liquid or gel containing a milk component, or a dry solid (powder, granule, tablet, etc.) containing a milk component. Here, in the present invention, the "liquid high-protein dairy raw material" is a liquid or gel fluid containing a high concentration of protein, preferably a liquid fluid containing a high concentration of protein. In the present invention, the "liquid high-protein dairy raw material" is not particularly limited, but preferably has a protein content of 60% or more by mass of the total solid content, that is, 60% or more by mass and 100% or less by mass, more preferably has a protein content of 65% or more by mass and 100% or less by mass, even more preferably has a protein content of 70% or more by mass and 100% or less by mass, even more preferably has a protein content of 75% or more by mass and 100% or less by mass, and particularly preferably has a protein content of 80% or more by mass and 100% or less by mass. In this case, in the present invention, examples of "liquid high-protein dairy raw material" include a reduced solution of milk protein concentrate (MPC: protein content of about 80% by mass of total solids), a reduced solution of whey protein concentrate (WPC: protein content of about 80% by mass of total solids), a reduced solution of whey protein isolate (WPI: protein content of about 90% by mass of total solids), and a reduced solution of caseinate (sodium caseinate, calcium caseinate, etc.: protein content of about 95% by mass of total solids), and among these, liquid milk protein concentrate (MPC) or liquid whey protein concentrate (WPC) is preferred.

[0013] In the present invention, the term "solid high-protein dairy raw material" refers to a dry product such as a powder, granule, or tablet containing a high concentration of protein, preferably a powder or granule-shaped dry product containing a high concentration of protein, and more preferably a powder-shaped dry product containing a high concentration of protein. In the present invention, the term "solid high-protein dairy raw material" is not particularly limited, but preferably has a protein content of 60% or more by mass, i.e., 60% to 100% by mass, more preferably, has a protein content of 65% to 100% by mass, more preferably, has a protein content of 70% to 100% by mass, even more preferably, has a protein content of 75% to 100% by mass, and particularly preferably, has a protein content of 80% to 100% by mass. In this case, in the present invention, examples of "solid high-protein dairy raw material" include powder of milk protein concentrate (MPC: protein content of about 80% by mass of total solids), powder of whey protein concentrate (WPC: protein content of about 80% by mass of total solids), powder of whey protein isolate (WPI: protein content of about 90% by mass of total solids), powder of caseinate (sodium caseinate, calcium caseinate, etc.: protein content of about 95% by mass of total solids), etc., and among these, solid milk protein concentrate (MPC) or solid whey protein concentrate (WPC) is preferred.

[0014] The dairy raw material used as a starting raw material in the production method of the present invention may be either the above-mentioned "liquid high-protein dairy raw material" or the above-mentioned "solid high-protein dairy raw material".

[0015] In the present invention, the term "liquid milk protein concentrate (MPC)" refers to a milk protein concentrate prepared by concentrating in a liquid state a "liquid high-protein milk raw material" obtained by using a reconstituted liquid of a milk protein concentrate or a liquid milk protein concentrate as a starting milk raw material, and is preferably a liquid containing milk protein in an amount of 60 to 100% by weight based on the total solid content. The term "prepared by concentrating in a liquid state" preferably refers to concentrating milk protein while removing ash and lactose from the liquid high-protein milk raw material by ultrafiltration.

[0016] In the present invention, the term "liquid whey protein concentrate (WPC)" refers to a whey protein concentrate prepared by concentrating a "liquid high-protein milk raw material" obtained by using a whey protein concentrate reconstituted solution or a liquid whey protein concentrate as a starting milk raw material, while still in a liquid state, and is preferably a liquid containing whey protein at 60 to 100% by weight based on the total solid content. The term "prepared by concentrating while still in a liquid state" preferably refers to concentrating whey protein while removing ash and lactose from the liquid high-protein milk raw material by ultrafiltration.

[0017] A "solid milk protein concentrate (MPC)" or a "solid whey protein concentrate (WPC)" can be obtained by subjecting the above-mentioned "liquid milk protein concentrate (MPC)" or "liquid whey protein concentrate (WPC)", respectively, to a drying process.

[0018] In the present invention, the term "dairy fluid" refers to a liquid or gel-like fluid that contains milk components, and is preferably a liquid fluid. In the present invention, the term "high-protein dairy fluid" refers to a liquid or gel-like fluid that contains a high concentration of protein, and is preferably a liquid fluid that contains a high concentration of protein, and is preferably a fluid in which the protein content of the total solid content is 60% by mass or more, i.e., 60% by mass or more and 100% by mass or less, and more preferably, Of the total solid content, the protein content is preferably 65% ​​by mass or more and 100% by mass or less, more preferably 70% by mass or more and 100% by mass or less, even more preferably 75% by mass or more and 100% by mass or less, and particularly preferably 80% by mass or more and 100% by mass or less. In this case, in the present invention, examples of "high-protein dairy fluid" include a reduced solution of milk protein concentrate (MPC: protein content of about 80% by mass of total solids), a reduced solution of whey protein concentrate (WPC: protein content of about 80% by mass of total solids), a reduced solution of whey protein isolate (WPI: protein content of about 90% by mass of total solids), a reduced solution of caseinate (sodium caseinate, calcium caseinate, etc.: protein content of about 95% by mass of total solids), a liquid milk protein concentrate, a liquid whey protein concentrate, a liquid whey protein isolate, and the like.

[0019] According to a preferred embodiment of the present invention, in the method for producing a high-protein dairy raw material, the concentration ratio of the retentate when concentrating the dairy fluid with a nanofiltration membrane is 1.1 times or more in terms of refractive index (Brix).

[0020] In the present invention, "concentrating a milk fluid with a nanofiltration membrane" means supplying the milk fluid to a nanofiltration membrane unit (such as a pressure vessel) in a batch or continuous manner, separating the milk fluid (supply liquid) into a retentate and a permeate, and then recovering the retentate (liquid milk raw material). In this case, when the milk fluid is concentrated with a nanofiltration membrane, proteins, carbohydrates, and divalent ions (magnesium ions, calcium ions, etc.) are mainly concentrated in the retentate, and a portion of monovalent ions (sodium ions, potassium ions, chloride ions, etc.) are mainly transferred to the permeate. In the present invention, the temperature at which the milk fluid is concentrated with a nanofiltration membrane is actually 3 to 20°C, preferably 3 to 15°C, more preferably 3 to 10°C, and even more preferably 5 to 10°C.

[0021] In the present invention, the type of nanofiltration membrane (NF membrane) is not particularly limited, but examples of the type of nanofiltration membrane include NF245-3838 / 30-FF (manufactured by DOW Water & Process Solutions) and DK1812 (manufactured by GE Power & Water). In the present invention, the shape of the nanofiltration membrane (NF membrane) is not particularly limited, but examples of the shape of the nanofiltration membrane include a flat membrane, a spiral membrane, a tubular membrane, a vibrating membrane, and a rotating membrane.

[0022] In the present invention, the concentration ratio of the retentate in concentrating a high-protein milk fluid with a nanofiltration membrane is not particularly limited, but is, for example, 1.1 times or more, preferably 1.1 times or more and 2 times or less, more preferably 1.1 times or more and 1.7 times or less, even more preferably 1.1 times or more and 1.5 times or less, even more preferably 1.2 times or more and 1.4 times or less, and even more preferably 1.2 times or more and 1.3 times or less, in terms of refractive index (Brix). Here, by setting the concentration ratio of the retentate in concentrating a high-protein milk fluid with a nanofiltration membrane to the above values, it is possible to appropriately remove unnecessary flavors while appropriately leaving flavors necessary for a milk raw material, and therefore the flavor can be well adjusted in the high-protein milk raw material.

[0023] According to a preferred embodiment of the present invention, in preparing a high-protein milk fluid from a milk raw material (preferably a solid high-protein milk raw material), the method for producing the high-protein milk raw material is such that the concentration of total solids in the high-protein milk fluid is 2 to 20% by mass, preferably 2 to 15% by mass. Here, in the present invention, "preparing a high-protein milk fluid from a milk raw material (preferably a solid high-protein milk raw material)" refers to, for example, dissolving (reducing) a solid high-protein milk raw material in water or hot water (warm water, hot water) to prepare the high-protein milk raw material. This means creating an aqueous solution, emulsion, suspension, etc. of the compound.

[0024] In the present invention, the concentration of the total solids in the high-protein dairy fluid is not particularly limited, but is preferably 1.5 to 18% by mass, more preferably 2 to 15% by mass (or 1.5 to 13% by mass), even more preferably 3 to 13% by mass, even more preferably 4 to 11% by mass, even more preferably 5 to 11% by mass, and even more preferably 5 to 10% by mass. By setting the concentration of the total solids in the high-protein dairy fluid to the above values, for example, it becomes easier to dissolve (reduc) the solid high-protein dairy raw material in water or hot water, and it becomes easier to prepare an aqueous solution, emulsion, suspension, etc. of the high-protein dairy raw material.

[0025] According to a preferred embodiment of the present invention, there is provided a method for producing a high-protein dairy fluid, wherein, when preparing a high-protein dairy fluid from a dairy raw material (preferably a solid high-protein dairy raw material), the protein concentration in the high-protein dairy fluid is 1.5 to 13 mass%.

[0026] In the present invention, the protein concentration in the high-protein dairy fluid is not particularly limited, but is preferably 1.5 to 13% by mass, more preferably 2 to 11% by mass, even more preferably 2.5 to 9% by mass, even more preferably 3.5 to 9% by mass, and even more preferably 4 to 9% by mass. By setting the protein concentration of the high-protein dairy fluid to the above values, for example, it becomes easier to dissolve (reduc) a solid high-protein dairy raw material in water or hot water, and it becomes easier to prepare an aqueous solution, emulsion, suspension, etc. of the high-protein dairy raw material.

[0027] According to a preferred embodiment of the present invention, a high-protein milk fluid (preferably a high-protein milk fluid having a protein content of 60% by mass or more in the total solid content) is prepared from a solid high-protein milk raw material having a protein content of 60% by mass or more in the total solid content, and this high-protein milk fluid is concentrated with a nanofiltration membrane and then dried (the liquid high-protein milk raw material obtained by the concentration treatment with the nanofiltration membrane is dried), which is a method for producing a solid high-protein milk raw material obtained by the drying treatment. In this case, the present invention is also a method for producing a solid high-protein milk raw material having improved refreshing feeling and / or good flavor. The present invention is also a method for producing a solid high-protein milk raw material having reduced protein odor and / or good flavor. The present invention is also a method for producing a solid high-protein milk raw material having reduced reduction odor and / or good flavor. Here, in the present invention, in the method for producing a solid high-protein milk raw material obtained by a drying process after a nanofiltration membrane concentration process, various operating conditions, etc. may be the same as those in the method for producing a liquid high-protein milk raw material obtained by a concentration process using a nanofiltration membrane.

[0028] In the present invention, the temperature of the blown air used to dry the liquid high-protein milk raw material obtained by concentration treatment with a nanofiltration membrane is preferably 150 to 250° C., more preferably 160 to 230° C., even more preferably 170 to 210° C., and even more preferably 180 to 200° C. In the present invention, the temperature of the exhaust air used to dry the liquid high-protein milk raw material obtained by concentration treatment with a nanofiltration membrane is preferably 60 to 100° C., more preferably 65 to 95° C., even more preferably 70 to 90° C., and even more preferably 75 to 85° C.

[0029] According to a preferred embodiment of the present invention, when the refractive index (Brix) of the milk raw material produced by the production method of the present invention and the refractive index (Brix) of a high-protein milk fluid are adjusted to be the same (equivalent), and the dimethyldisulfide (DMDS) content is measured, the dimethyldisulfide content in the milk raw material produced by the production method of the present invention is 20 times higher than the dimethyldisulfide content in the milk fluid. That is, in a preferred embodiment of the present invention, the high-protein milk raw material produced by the production method of the present invention has a change rate of dimethyl disulfide content of 20% or more compared to a high-protein milk fluid after adjusting the refractive index to the same value.

[0030] In a preferred embodiment of the present invention, in a liquid high-protein milk raw material obtained by concentration treatment with a nanofiltration membrane, the rate of change in the dimethyl disulfide content is 20% or more, preferably 20 to 90%, more preferably 40 to 85%, and even more preferably 60 to 85%, after adjusting the refractive index to the same, compared to a high-protein milk fluid. Also, in a preferred embodiment of the present invention, in a solid high-protein milk raw material obtained by drying treatment after concentration treatment with a nanofiltration membrane, the rate of change in the dimethyl disulfide content is 10% or more, preferably 10 to 80%, more preferably 20 to 70%, and even more preferably 30 to 60%, after adjusting the refractive index to the same, compared to a high-protein milk fluid.

[0031] According to a preferred embodiment of the present invention, in the method for producing a high-protein milk raw material, when the refractive index of the milk raw material produced by the production method of the present invention and the refractive index of a high-protein milk fluid are adjusted to be the same and the nonanal content is measured, the nonanal content in the milk raw material produced by the production method of the present invention changes by 40% or less compared to the nonanal content in the milk fluid. That is, in a preferred embodiment of the present invention, in the high-protein milk raw material produced by the production method of the present invention, the rate of change in the nonanal content is 40% or less compared to the high-protein milk fluid after adjusting the refractive index to be the same.

[0032] In a preferred embodiment of the present invention, in a liquid high-protein milk raw material obtained by concentration treatment with a nanofiltration membrane, the rate of change in the nonanal content is 40% or less, preferably 0 to 40%, more preferably 0 to 30%, and even more preferably 0 to 20%, after adjusting the refractive index sugar content to the same, compared to a high-protein milk fluid. Also, in a preferred embodiment of the present invention, in a solid high-protein milk raw material obtained by drying treatment after concentration treatment with a nanofiltration membrane, the rate of change in the nonanal content is 0% or more, preferably 0 to 50%, more preferably 0 to 40%, and even more preferably 0 to 30%, after adjusting the refractive index sugar content to the same, compared to a high-protein milk fluid.

[0033] According to a preferred embodiment of the present invention, when the refractive index of the milk raw material produced by the production method of the present invention and the refractive index of a high-protein milk fluid are adjusted to be the same and the pentanal content is measured, the pentanal content in the milk raw material produced by the production method of the present invention changes by 40% or less compared to the pentanal content in the milk fluid. That is, in a preferred embodiment of the present invention, the high-protein milk raw material produced by the production method of the present invention changes the pentanal content by 40% or less compared to the high-protein milk fluid after adjusting the refractive index to be the same.

[0034] In a preferred embodiment of the present invention, in a liquid high-protein milk raw material obtained by concentration treatment with a nanofiltration membrane, the rate of change in the pentanal content is 40% or less, preferably 0 to 40%, more preferably 0 to 30%, and even more preferably 0 to 20%, after adjusting the refractive index to the same, compared to a high-protein milk fluid. Also, in a preferred embodiment of the present invention, in a solid high-protein milk raw material obtained by drying treatment after concentration treatment with a nanofiltration membrane, the rate of change in the pentanal content is 40% or less, preferably 0 to 50%, more preferably 0 to 40%, and even more preferably 0 to 30%, after adjusting the refractive index to the same, compared to a high-protein milk fluid.

[0035] According to a preferred embodiment of the present invention, when the refractive index of the milk raw material produced by the production method of the present invention and the refractive index of the high-protein milk fluid are adjusted to be the same and the pentanol content is measured, the pentanol content in the milk raw material produced by the production method of the present invention changes by 5% or more compared to the pentanol content in the milk fluid. That is, in a preferred embodiment of the present invention, the high-protein milk raw material produced by the production method of the present invention has a pentanol content change rate of 5% or more compared to the high-protein milk fluid after adjusting the refractive index to be the same.

[0036] In a preferred embodiment of the present invention, in the liquid high-protein milk raw material obtained by concentration treatment with a nanofiltration membrane, the rate of change in the pentanol content is 60% or less, preferably 5 to 60%, more preferably 10 to 50%, and even more preferably 20 to 50%, after adjusting the refractive index to the same, compared to the high-protein milk fluid. Also, in a preferred embodiment of the present invention, in the solid high-protein milk raw material, the rate of change in the pentanol content is 60% or less, preferably 0 to 40%, more preferably 0 to 30%, and even more preferably 0 to 20%, after adjusting the refractive index to the same, compared to the high-protein milk fluid obtained by drying treatment after concentration treatment with a nanofiltration membrane.

[0037] In the present invention, the rate of change in the content of aroma components (flavor substances) such as dimethyldisulfide, nonanal, pentanal, pentanol, and aminoacetophenone can be evaluated by, for example, the relative value of each sample by the following method. (1) After adjusting the refractive index of each sample to 5%, place these samples (volume: 8 mL) and sodium chloride (weight: 3 g) in vials (volume: 20 mL), add methyl isobutyl ketone (MIBK) as an internal standard, and seal. (2) Heat the vial at 60°C for 40 minutes. (3) The "aroma (odor) components" in the headspace of the vial are extracted using a solid-phase microfiber (50 / 30 μm DVB / CAR / PDMS). (4) The solid phase microfiber is analyzed using a gas chromatograph mass spectrometer (GC / MS, column: DB-WAX UI). (5) Using solid-phase microextraction (SPME), the area values ​​of the aroma components are identified, and the behavior of the changes in the aroma components accompanying the nanofiltration membrane concentration process is evaluated based on the ratio (relative value) of the changes in the aroma components after the nanofiltration membrane concentration process to the ratio before the nanofiltration membrane concentration process. Here, solid-phase microextraction is a technology that can analyze volatile aroma components quickly and with high sensitivity.

[0038] In a preferred embodiment of the present invention, the change in nutritional component concentrations (total solids, lipids, proteins, carbohydrates (sugars), ash) of the liquid or solid high-protein milk raw material after concentration treatment with a nanofiltration membrane is 50% or less, and / or the change in salt component concentrations (Na, K, Mg, Ca, Cl, P) is 80% or less, compared to the high-protein milk fluid before concentration treatment with a nanofiltration membrane. The liquid or solid high-protein milk raw material produced by the production method of the present invention is further advantageous in that it can provide a high-protein milk raw material with improved refreshing taste and good flavor, with almost no change in nutritional components and salt components.

[0039] In a more preferred embodiment of the present invention, the change in the total solids concentration of the liquid or solid high-protein dairy raw material after the nanofiltration membrane treatment is 20% or less, preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less, compared to the high-protein dairy fluid before the nanofiltration membrane treatment. The total solids concentration of the dairy raw material can be determined, for example, based on the method described in the following examples.

[0040] In a more preferred embodiment of the present invention, the change in lipid concentration of the liquid or solid high-protein dairy raw material after nanofiltration membrane treatment is 50% or less, preferably 40% or less, more preferably 30% or less, and even more preferably 25% or less, compared to the high-protein dairy fluid before nanofiltration membrane treatment. The lipid concentration of the dairy raw material can be determined by measurement using the Gerber method (see "2. Lipids (3) Gerber method" in "Attached Analytical Methods for Nutritional Components, etc.", which corresponds to the details of the method listed in Column 3 of Appendix 9 of the Food Labeling Standards (Cabinet Office Ordinance No. 10 of 2015)).

[0041] In a more preferred embodiment of the present invention, the change in protein concentration of the liquid or solid high-protein dairy raw material after nanofiltration membrane processing is 20% or less, preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less, compared to the high-protein dairy fluid before nanofiltration membrane processing. The protein concentration of the dairy raw material can be determined by measuring it by the Lowry method (see "Protein Quantitative Method I", Chemistry and Biology, Vol. 4, No. 1, 1966, pp. 37-44).

[0042] In a more preferred embodiment of the present invention, the percentage change in carbohydrate (sugar) concentration of the liquid or solid high-protein dairy raw material after nanofiltration membrane treatment is, for example, 40% or less, preferably 35% or less, more preferably 30% or less, and even more preferably 25% or less, compared to the high-protein dairy fluid before nanofiltration membrane treatment. The carbohydrate (sugar) concentration of the dairy raw material can be determined, for example, based on the method described in the Examples below.

[0043] In a more preferred embodiment of the present invention, the change in ash concentration of the liquid or solid high-protein dairy raw material after nanofiltration membrane treatment is 20% or less, preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less, compared to the high-protein dairy fluid before nanofiltration membrane treatment. The ash concentration of the dairy raw material can be determined, for example, based on the method described in the following examples.

[0044] In a more preferred embodiment of the present invention, the change in sodium (Na) concentration of the liquid or solid high-protein dairy raw material after nanofiltration membrane treatment compared to the high-protein dairy fluid before nanofiltration membrane treatment is 35% or less, preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less.

[0045] In a more preferred embodiment of the present invention, the percentage change in potassium (K) concentration of the liquid or solid high-protein dairy raw material after nanofiltration membrane treatment compared to the high-protein dairy fluid before nanofiltration membrane treatment is, for example, 20% or less, preferably 15% or less, more preferably 10% or less, and even more preferably 5% or less.

[0046] In a more preferred embodiment of the present invention, the percentage change in magnesium (Mg) concentration of the liquid or solid high-protein dairy raw material after nanofiltration membrane treatment compared to the high-protein dairy fluid before nanofiltration membrane treatment is, for example, 25% or less, preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less.

[0047] In a more preferred embodiment of the present invention, the percentage change in calcium (Ca) concentration of the liquid or solid high-protein dairy raw material after nanofiltration membrane treatment compared to the high-protein dairy fluid before nanofiltration membrane treatment is, for example, 30% or less, preferably 25% or less, more preferably 20% or less, and even more preferably 15% or less.

[0048] In a more preferred embodiment of the present invention, the phosphorus (P) of the liquid or solid high protein dairy raw material after nanofiltration membrane treatment is compared to the high protein dairy fluid before nanofiltration membrane treatment. The rate of change in concentration is, for example, 20% or less, preferably 15% or less, more preferably 10% or less, and further preferably 5% or less.

[0049] Here, the sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), and phosphorus (P) concentrations in the milk raw materials can be determined by measurement using inductively coupled plasma (ICP) atomic emission spectrometry (see “10 Potassium (3) Inductively Coupled Plasma Atomic Emission Spectroscopy,” “11 Calcium (3) Inductively Coupled Plasma Atomic Emission Spectroscopy,” “16 Sodium (equivalent to salt) (3) Inductively Coupled Plasma Atomic Emission Spectroscopy,” and “21 Phosphorus (3) Inductively Coupled Plasma Atomic Emission Spectroscopy” in the “Attachment: Analytical Methods for Nutritional Components, etc.”, which correspond to the details of the method set out in Column 3 of Appendix 9 of the Food Labeling Standards (Cabinet Office Ordinance No. 10 of 2015)).

[0050] In a more preferred embodiment of the present invention, the change in chlorine (Cl) concentration of the solid high-protein milk raw material after nanofiltration membrane treatment is, for example, 80% or less, preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less, compared to the high-protein milk fluid before nanofiltration membrane treatment. The chlorine (Cl) concentration of the milk raw material can be determined by measuring it by a rotating electrode polarographic method.

[0051] [Food and beverage products and their manufacturing methods] According to one aspect of the present invention, there is provided a method for producing a food or beverage, the method comprising the step of incorporating a dairy ingredient produced by the production method of the present invention into the food or beverage.

[0052] Any component other than the milk raw material produced by the production method of the present invention can be added to the food or drink containing the milk raw material produced by the production method of the present invention, if necessary. Such optional components are not particularly limited, but include components that are usually blended into food or drink, such as water-based raw materials, oil-based raw materials, carbohydrates, dietary fiber, polysaccharides, proteins, peptides, amino acids, lipids, organic acids, various physiologically active substances, vitamins, minerals, acidulants, flavorings, sweeteners, emulsifiers, thickeners, gelling agents, functional ingredients, oils and fats, excipients, colorants, preservatives, water (hot water, warm water, room temperature water, cold water), etc.

[0053] According to a preferred embodiment of the present invention, there is provided a method for producing a food or beverage, comprising the step of mixing one or more selected from the group consisting of water-based raw materials, oil-based raw materials, flavors, sweeteners, emulsifiers, thickeners, gelling agents, functional ingredients, fats and oils, excipients, and water with a milk raw material produced by the production method of the present invention, and containing the mixture in the food or beverage. Here, water can be, for example, hot water, warm water, room temperature water, or cold water. Here, mixing can mean mixing the milk raw material produced by the production method of the present invention with any of the above-mentioned components before adding them to the food or beverage, and adding the mixture to the food or beverage, or adding the milk raw material produced by the production method of the present invention to the food or beverage, and then adding any of the above-mentioned components to the food or beverage, and mixing the milk raw material and the optional components in the food or beverage.

[0054] Examples of aqueous ingredients that can be contained in the food and beverage products of the present invention include dairy ingredients other than the dairy ingredients of the present invention (milk, skim milk, low-fat milk, composition-adjusted milk, etc.), dairy beverages, fermented milk, soy milk, fruit juice, vegetable juice, fruit / vegetable paste, fruit / vegetable extract, alcoholic beverages, liquid sugar, etc.

[0055] Examples of oil-based ingredients that can be contained in the food and beverage of the present invention include butter, margarine, shortening, cream, chocolate, cacao mass, cocoa butter, almond paste, and the like.

[0056] According to a more preferred aspect of the present invention, there is provided a method for producing a food or beverage, which includes a step of incorporating a milk raw material produced by the production method of the present invention into the food or beverage, wherein the milk raw material is a liquid high-protein milk raw material obtained by concentrating the milk raw material using a nanofiltration membrane.

[0057] According to a more preferred aspect of the present invention, there is provided a method for producing a food or beverage, which includes a step of incorporating a milk raw material produced by the production method of the present invention into the food or beverage, wherein the milk raw material is a solid (powdered) high-protein milk raw material obtained by a nanofiltration membrane concentration process and then a drying process.

[0058] Food and drink products that can contain the liquid or solid high-protein dairy raw material produced by the production method of the present invention may be in any form, such as a solution, suspension, emulsion, powder, paste, semi-solid molded product, solid molded product, etc., as long as they are in a form that can be orally ingested, and are not particularly limited. For example, instant foods such as instant noodles, retort foods, canned foods, microwave foods, instant soups, miso soups, freeze-dried foods, etc.; beverages such as soft drinks, fruit juice drinks, vegetable drinks, soy milk drinks, coffee drinks, tea drinks, powdered drinks, concentrated drinks, alcoholic drinks, etc.; bread, pasta, noodles, cake mix, breadcrumbs, etc. Flour products; candy, caramel, chewing gum, chocolate, cookies, biscuits, bars, cakes, pies, snacks, crackers, Japanese sweets, mousse, dessert sweets, ice creams, and other confectioneries; sauces, tomato-processed seasonings, flavor seasonings, cooking mixes, sauces, dressings, soups, curry and stew bases, and other seasonings; processed oils and fats, butter, margarine, mayonnaise, and other oils and fats; dairy products such as milk drinks, yogurts, lactic acid bacteria drinks, ice creams, and creams; canned agricultural goods, jams, marmalades, cereals, and other agricultural processed products; frozen foods, liquid diets, etc. The food and drink also includes health foods, functional foods (including, for example, foods for specified health uses, foods with nutritional functions, or foods with functional claims), nutritional supplements, foods for special dietary uses (including, for example, foods for sick people, infant formulas, powdered milk for pregnant women and lactating women, or foods for people with difficulty swallowing), or liquid infant formulas (also called liquid infant milk). Among these, beverages, confectioneries, dairy products, and liquid foods are preferred, and fermented milk, milk drinks, coffee drinks, tea drinks, soft drinks, powdered drinks, liquid foods, ice creams (ice cream, ice milk, lacto ice cream), ice creams, and puddings are more preferred, with coffee drinks being particularly preferred. The liquid or solid high-protein dairy ingredients produced by the production method of the present invention are advantageous in that they improve the refreshing feeling, do not inhibit the original flavor of the food and drink to which they are mixed, and can enhance the protein content in the food and drink while maintaining a favorable flavor.

[0059] According to a more preferred embodiment of the present invention, there is provided a method for producing a food or drink, comprising a step of incorporating a dairy ingredient produced by the production method of the present invention into the food or drink, wherein the food or drink is a dairy product, fermented milk, a milk drink, a coffee drink, a tea drink, a soft drink, a liquid meal, ice cream, or ice cream. Examples of ice cream include ice cream, ice milk, and lacto ice cream.

[0060] According to a preferred embodiment of the present invention, there is provided a method for producing a food or drink with improved refreshing taste, comprising a step of incorporating a dairy ingredient produced by the production method of the present invention into the food or drink. Here, "improved refreshing taste" means that, in a protein-containing food or drink, there is reduced unpleasant taste, reduced cooked odor, reduced sulfur odor, reduced powdery flavor, etc.

[0061] According to another preferred embodiment of the present invention, there is provided a method for producing a food or drink with reduced protein odor, the method comprising the step of adding a milk raw material produced by the production method of the present invention to the food or drink. Here, "reduced protein odor" means that, in a protein-containing food or drink, the unpleasant taste derived from a high concentration of protein is reduced, and flavor substances such as dimethyl disulfide are reduced.

[0062] According to a preferred embodiment of the present invention, there is provided a method for producing a food or beverage with reduced reduction odor, the method comprising the step of incorporating a dairy ingredient produced by the production method of the present invention into the food or beverage.

[0063] According to another aspect of the present invention, there is provided a food or drink containing a dairy raw material produced by the production method of the present invention. The food or drink containing a dairy raw material produced by the production method of the present invention may be the same as the food or drink that can contain the liquid or solid high-protein dairy raw material produced by the production method of the present invention described above.

[0064] As described above, any component other than the milk raw material produced by the production method of the present invention can be added to the food and drink of the present invention. According to a preferred embodiment of the present invention, there is provided a food and drink that further contains, in addition to the milk raw material produced by the production method of the present invention, one or more selected from the group consisting of water-based raw materials, oil-based raw materials, flavorings, sweeteners, emulsifiers, thickeners, gelling agents, functional ingredients, oils and fats, excipients, and water (hot water, warm water, room temperature water, and cold water).

[0065] According to a preferred aspect of the present invention, there is provided a food or beverage product containing a dairy ingredient produced by the manufacturing method of the present invention, wherein the dairy ingredient is a liquid high-protein product obtained by concentrating the dairy ingredient using a nanofiltration membrane.

[0066] According to a preferred embodiment of the present invention, there is provided a food or beverage product containing a milk ingredient produced by the manufacturing method of the present invention, wherein the milk ingredient is a solid (powdered) high-protein product obtained by a nanofiltration membrane concentration process followed by a drying process.

[0067] According to a preferred embodiment of the present invention, there is provided a food or beverage containing a dairy ingredient produced by the manufacturing method of the present invention, the food or beverage being a dairy product, fermented milk, a milk drink, a coffee drink, a tea drink, a soft drink, a liquid meal, an ice cream dessert, or ice cream (ice cream, ice milk, lacto ice cream).

[0068] According to a preferred embodiment of the present invention, there is provided a food or drink having an improved refreshing taste, which contains a dairy ingredient produced by the production method of the present invention.

[0069] According to another preferred aspect of the present invention, there is provided a food or beverage having a reduced protein odor, which contains a dairy ingredient produced by the production method of the present invention.

[0070] According to another preferred aspect of the present invention, there is provided a food or beverage having a reduced reduction odor, which contains a dairy ingredient produced by the production method of the present invention.

[0071] The food and beverage products of the present invention may be produced by any production method as long as they contain the milk raw material produced by the production method of the present invention. For example, they can be produced by mixing any of the above-mentioned components with the milk raw material produced by the production method of the present invention to form a mixture, and then adding the mixture to the food and beverage products.

[0072] In addition, when producing the food or drink of the present invention, sterilization (preferably heat sterilization) may be performed before, after, or while adding the milk raw material produced by the production method of the present invention to the food or drink. Heat sterilization can be performed by methods and equipment commonly used in the food industry, such as low temperature hold sterilization (LTLT), high temperature hold sterilization (HTLT), high temperature short time sterilization (HTST), and ultra-high temperature flash sterilization (UHT). Equipment for heat sterilization includes indirect heating sterilizers (plate sterilizers and tube sterilizers, etc.), direct heating sterilizers (steam injection sterilizers and steam infusion sterilizers, etc.), electric heating sterilizers, retort sterilizers, tanks with stirring and temperature control functions, and tanks with stirring, temperature control, decompression, and homogenization functions. In addition, the above-mentioned optional components may be added at any timing before or after sterilization, or may be added during sterilization, or may be added after packaging as described below. The sterilized food and drink of the present invention has a high protein content even after sterilization (e.g., heat sterilization). Even though the sterilized food and drink of the present invention contains high-quality dairy ingredients, the effects of improving the refreshing feeling and reducing the protein odor are maintained. The sterilized food and drink of the present invention maintains the above effects even when subjected to retort sterilization, which is the most severe condition for heat sterilization, and therefore the above effects are also maintained when subjected to sterilization under other milder conditions.

[0073] Furthermore, the food and drink of the present invention may be a packaged food and drink (preferably a sterilized packaged food and drink). For example, a packaged beverage can be obtained by filling a container with a liquid obtained by mixing the milk raw material produced by the production method of the present invention with an optional component and sealing it. The container used for the packaged food and drink can be a molded container mainly made of polyethylene terephthalate (so-called PET bottle), a metal can, a paper container combined with a metal foil or a plastic film, a bottle, or the like, as in the case of general foods and drinks, as long as it has a normal shape. In addition, the heat sterilization treatment of the packaged food and drink is carried out under the sterilization conditions stipulated in the Food Sanitation Act, for example, when the container can be sterilized by heat after filling into a container such as a metal can. For those that cannot be sterilized by retort, such as PET bottles and paper containers, a method is adopted in which the food and drink are sterilized under the same sterilization conditions as above, for example, sterilized at high temperature for a short time using a plate-type heat exchanger, cooled to a certain temperature, and filled into a container. In addition, another component may be mixed and filled into the filled container under aseptic conditions. The packaged food and drink of the present invention maintains the effects of improved refreshing feeling and reduced protein odor even after being packaged (preferably after being packaged and sterilized), despite containing high-protein dairy ingredients. The sterilized packaged food and drink of the present invention maintains the above effects even when subjected to retort sterilization, which is the severest heat sterilization treatment condition after filling into a container, and therefore maintains the above effects even when packaged and sterilized under other milder conditions.

[0074] According to a preferred embodiment of the present invention, there is provided a method for producing sterilized (preferably heat-sterilized) food or beverage, which comprises a step of incorporating a dairy raw material produced by the production method of the present invention into the food or beverage.

[0075] According to a preferred embodiment of the present invention, there is provided a sterilized (preferably heat-sterilized) food or drink comprising a dairy ingredient produced by the production method of the present invention.

[0076] [Methods for improving the refreshing taste of dairy ingredients] According to another aspect of the present invention, there is provided a method for improving the refreshing feeling of a milk raw material (before nanofiltration membrane concentration treatment), which comprises preparing a high-protein milk fluid (preferably a high-protein milk fluid having a protein content of 60% by mass or more in the total solid content) from a milk raw material (preferably a solid high-protein milk raw material having a protein content of 60% by mass or more in the total solid content), and concentrating the milk fluid with a nanofiltration membrane to obtain a liquid high-protein milk raw material. The refreshing feeling of the milk raw material used as a starting raw material in the production method of the present invention can be improved by concentrating the milk raw material with a nanofiltration membrane or the like. Here, in the present invention, various operating conditions, etc. of the method for improving the refreshing feeling of the milk raw material before nanofiltration membrane concentration treatment may be the same as those of the method for producing a liquid high-protein milk raw material obtained by concentrating the milk raw material with a nanofiltration membrane.

[0077] According to a preferred embodiment of the present invention, a high-protein milk fluid prepared from a milk raw material and having a protein content of 60% by mass or more in the total solid content is concentrated using a nanofiltration membrane, followed by drying (the liquid high-protein milk raw material is dried) to obtain a solid high-protein milk raw material. Here, in the present invention, the various operating conditions of the method for improving the refreshing feeling of the milk raw material before the nanofiltration membrane concentration process are the same as those of the method for producing the solid high-protein milk raw material obtained by drying after the nanofiltration membrane concentration process.

[0078] In the present invention, "improving the refreshing feeling" means reducing unpleasant flavors, cooked odors, sulfur odors, powdery flavors, and the like in protein-containing foods and beverages.

[0079] [Method for reducing protein odor in dairy ingredients] According to another aspect of the present invention, a method for reducing the protein odor of a milk raw material (before nanofiltration membrane concentration treatment) is provided, which comprises preparing a high-protein milk fluid (preferably a high-protein milk fluid having a protein content of 60% by mass or more in the total solid content) from a milk raw material (preferably a solid high-protein milk raw material having a protein content of 60% by mass or more in the total solid content), and concentrating the milk fluid with a nanofiltration membrane to obtain a liquid high-protein milk raw material. The protein odor of the milk raw material used as the starting raw material in the production method of the present invention can be reduced by subjecting the milk raw material to a nanofiltration membrane concentration treatment or the like. Here, in the present invention, the various operating conditions, etc. of the method for reducing the protein odor of the milk raw material before nanofiltration membrane concentration treatment are the same as those of the production method of the liquid high-protein milk raw material obtained by concentrating the milk raw material with a nanofiltration membrane.

[0080] According to a preferred embodiment of the present invention, a high-protein milk fluid prepared from a milk raw material and having a protein content of 60% by mass or more in the total solid content is concentrated with a nanofiltration membrane and then dried (the liquid high-protein milk raw material is dried) to obtain a solid high-protein milk raw material. Here, in the present invention, the various operating conditions of the method for reducing the protein odor of a milk raw material before the nanofiltration membrane concentration process are the same as those of the method for producing a solid high-protein milk raw material obtained by drying after the nanofiltration membrane concentration process.

[0081] In the present invention, "reduction of protein odor" means reduction of unpleasant flavors derived from high concentrations of proteins, reduction of flavor substances such as dimethyl disulfide, etc. in protein-containing foods and beverages.

[0082] [Method for reducing reduction odor of dairy ingredients] According to another aspect of the present invention, a method for reducing the reduction odor of a milk raw material (before nanofiltration membrane concentration treatment) is provided, which comprises preparing a high-protein milk fluid (preferably a high-protein milk fluid having a protein content of 60% by mass or more in the total solid content) from a milk raw material (preferably a solid high-protein milk raw material having a protein content of 60% by mass or more in the total solid content), and concentrating the milk fluid with a nanofiltration membrane to obtain a liquid high-protein milk raw material. The reduction odor of the milk raw material used as the starting raw material in the production method of the present invention can be reduced by subjecting the milk raw material to a nanofiltration membrane concentration treatment or the like. Here, in the present invention, the various operating conditions, etc. of the method for reducing the reduction odor of the milk raw material before nanofiltration membrane concentration treatment are the same as those of the production method of the liquid high-protein milk raw material obtained by concentrating the milk raw material with a nanofiltration membrane.

[0083] According to a preferred embodiment of the present invention, a high-protein milk fluid prepared from a milk raw material and having a protein content of 60% by mass or more in the total solid content is concentrated with a nanofiltration membrane, followed by drying (the liquid high-protein milk raw material is dried) to obtain a solid high-protein milk raw material. Here, in the present invention, various operating conditions of the method for reducing the reduction odor of a milk raw material before the nanofiltration membrane concentration treatment are the same as those of the method for producing a solid high-protein milk raw material obtained by drying after the nanofiltration membrane concentration treatment. EXAMPLES

[0084] The present invention will be described in more detail below with reference to examples, but the technical scope of the present invention is not limited to the contents of these examples. In addition, the following examples are only a part of the embodiments specifically implemented by the present inventors, and other aspects that fall within the scope of the present invention other than the following examples. Although the effects of the invention have been confirmed even in this embodiment, they will not be specifically shown here.

[0085] Test Example 1: Concentration treatment of reconstituted milk protein concentrate (MPC) solution (high protein milk fluid) using nanofiltration membrane (NF membrane) 1 The study was carried out as follows. (1-1) A dairy raw material (MPC) (MPC4882, Fonterra) was dissolved in warm water (60°C) to prepare 10 kg of MPC reconstituted liquid (dairy fluid) (total solid content: 10 mass%, protein content: 8 mass%). (1-2) The reduced solution of MPC (10 °C) was filtered through a nanofiltration membrane (DK1812, GE Power & Water, membrane area: 0.32 m 2 ), MPC concentrates (NF membrane) were prepared at concentrations equivalent to 1.2, 1.3, and 1.4 times the concentration ratio of refractive index (Brix, measured value by a saccharometer) (the Brix of the untreated MPC reduced solution was 10.8%, the Brix of the MPC concentrated solution (NF membrane, 1.2 times) was 13.2%, the Brix of the MPC concentrated solution (NF membrane, 1.3 times) was 14.2%, and the Brix of the MPC concentrated solution (NF membrane, 1.4 times) was 15.3%). Note that when the MPC reduced solution (total solid content: 10% by weight, protein content: 8% by mass) was concentrated using a nanofiltration membrane, the average permeation flow rate was approximately 2 kg / m at Brix concentration ratios of 1 to 1.2 times. 2 / h, and when the Brix concentration ratio is 1.2 to 1.3 times, the average permeation flow rate is about 1.5 kg / m 2 / h, and when the Brix concentration ratio is 1.3 to 1.4 times, the average permeation flow rate is about 0.5 kg / m 2 / h. (1-3) The Brix of the MPC concentrated solution (NF membrane, 1.2x), the Brix of the MPC concentrated solution (NF membrane, 1.3x), and the Brix of the MPC concentrated solution (NF membrane, 1.4x) were adjusted (diluted) to be the same as the Brix of the untreated MPC reduced solution, to prepare an adjusted solution of the MPC concentrated solution (NF membrane, 1.2x) (Brix: 10%), an adjusted solution of the MPC concentrated solution (NF membrane, 1.3x) (Brix: 10%), and an adjusted solution of the MPC concentrated solution (NF membrane, 1.4x) (Brix: 10%).

[0086] The flavor of the adjusted solutions (Brix: 10%) of MPC concentrated solutions (NF membrane) obtained by the above steps (1-1) to (1-3) (three types: "NF membrane, 1.2 times", "NF membrane, 1.3 times", and "NF membrane, 1.4 times") was confirmed by a panel of 10 experts.

[0087] From the results of checking the flavor as described above, all 10 expert panel members rated that the adjusted solutions (Brix: 10%) of MPC concentrated solution (NF membrane) obtained by steps (1-1) to (1-3) above (three types of concentration ratios of the retentate when concentrating the milk fluid with a nanofiltration membrane: 1.2 times, 1.3 times, and 1.4 times in terms of refractive index (Brix)) had an improved refreshing feeling and reduced protein odor and reduced odor compared to the reduced solution of untreated MPC (Brix: 10%).

[0088] Test Example 2: Concentration treatment of reconstituted milk protein concentrate (MPC) solution (high protein milk fluid) using nanofiltration membrane (NF membrane) 2 This test was carried out as follows. This test (Test Example 2) was carried out on a larger scale than Test Example 1 (the amount of dairy raw materials and dairy fluid was large). (2-1) A dairy raw material (MPC) (MPC4882, Fonterra) was dissolved in warm water (60°C) to prepare 60 kg of MPC reconstituted liquid (dairy fluid) (total solid content: 10% by mass, protein content: 8% by mass). (2-2) The reduced solution of MPC (10 °C) was filtered through a nanofiltration membrane (NF245-3838 / 30-FF, DOW Water & Process Solutions), membrane area: 7.5 m 2 The MPC concentrate (NF membrane) was prepared at a concentration equivalent to a 1.2-fold concentration of refractive index (Brix, measured value by a saccharometer) while concentrating the solution using a 2× filter. (The untreated MPC reduced solution had a Brix of 10.6%, while the MPC concentrated solution (NF membrane, 1.2 When the MPC reduced solution (total solids content: 10% by weight, protein content: 8% by mass) was concentrated using a nanofiltration membrane, the average permeation flow rate was approximately 4.5 kg / m at a Brix concentration rate of 1 to 1.2 times. 2 / h. (2-3) The concentrated solution of MPC (NF membrane, 1.2 times) was spray-dried (air supply temperature: 180°C, exhaust temperature: 80°C) to prepare MPC powder (NF membrane, 1.2 times). (2-4) The MPC concentrated solution (NF membrane, 1.2 times) was adjusted (diluted) to the same Brix as the reduced solution of untreated MPC to prepare an adjusted solution of MPC concentrated solution (NF membrane, 1.2 times) (Brix: 10%), while MPC powder (NF membrane, 1.2 times) was dissolved to the same Brix as the reduced solution of untreated MPC to prepare a reduced solution of MPC powder (NF membrane, 1.2 times) (Brix: 10%).

[0089] A panel of 10 experts confirmed the flavor of the adjusted solution (Brix: 10%) of the MPC concentrated solution (NF membrane, 1.2 times) obtained by the above steps (2-1) to (2-4) and the reduced solution (Brix: 10%) of the MPC powder (NF membrane, 1.2 times).

[0090] From the results of checking the flavor as described above, compared to the reduced liquid of unprocessed MPC (Brix: 10%), the adjusted liquid (Brix: 10%) of the MPC concentrate (NF membrane, 1.2 times) after nanofiltration membrane concentration processing obtained by steps (2-1) to (2-4) above, and the reduced liquid (Brix: 10%) of the MPC powder (NF membrane, 1.2 times) after spray drying were both rated by all 10 expert panel members as having an improved refreshing feeling and reduced protein odor and reduced odor.

[0091] Test Example 3: Changes in aroma components during the concentration process of a reconstituted milk protein concentrate (MPC) solution (high-protein dairy fluid) using a nanofiltration membrane (NF membrane) This test was carried out as follows. In this test, changes in aroma components (flavor substances) of the reduced solution of untreated MPC, the reduced solution of MPC (NF membrane) prepared in Test Example 2, and the reduced solution of MPC powder (NF membrane) were evaluated. (3-1) As samples for measuring aroma components, a reduced solution (Brix: 5%) of untreated MPC, an adjusted solution (Brix: 5%) of concentrated MPC solution (NF membrane, 1.2 times), and a reduced solution (Brix: 5%) of MPC powder (NF membrane, 1.2 times) were prepared (the refractive index of each sample was adjusted to 5%). These samples (volume: 8 mL) and sodium chloride (weight: 3 g) were then placed in vials (volume: 20 mL), and methyl isobutyl ketone (MIBK) was added as an internal standard substance and the vials were sealed. (3-2) The vial was heated at 60°C for 40 minutes. (3-3) The “aroma (odor) components” in the headspace of the vial were extracted using a solid-phase microfiber (50 / 30 μm DVB / CAR / PDMS). (3-4) The solid phase microfiber was analyzed using a gas chromatograph mass spectrometer (GC / MS, column: DB-WAX UI). (3-5) The area values ​​of the aroma components were determined by solid-phase microextraction (SPME), and the behavior of the changes in the aroma components accompanying the nanofiltration membrane concentration process was evaluated by the ratio (relative value) of the change in the aroma components after the nanofiltration membrane concentration process to the change before the nanofiltration membrane concentration process. Here, the solid-phase microextraction method is a technology that can analyze volatile aroma components quickly with high sensitivity.

[0092] The following compounds were selected for evaluation as aroma components: dimethyldisulfide (DMDS, an indicator of protein deterioration), nonanal (an indicator of lipid deterioration), pentanal (an indicator of grass odor), and pentanol (an indicator of grass odor).

[0093] The untreated MPC reduced solution (Brix: 5%) was analyzed for dimethyldiamine based on the SPME method. The sulfide area value was set to 1, and the rate of change (relative value) in the area value of dimethyl disulfide based on the SPME method was calculated for the adjusted solution (Brix: 5%) of the MPC concentrated solution (NF membrane, 1.2 times) and the reduced solution (Brix: 5%) of the MPC powder (NF membrane, 1.2 times), and is shown in Figure 1.

[0094] According to Fig. 1, in the adjusted solution (Brix: 5%) of the MPC concentrated solution (NF membrane, 1.2 times), the dimethyl disulfide content changed (decreased) by 80% compared to the reduced solution of untreated MPC (Brix: 5%). Also, according to Fig. 1, in the reduced solution (Brix: 5%) of the MPC powder (NF membrane, 1.2 times), the dimethyl disulfide content changed (decreased) by 38% compared to the reduced solution of untreated MPC (Brix: 5%).

[0095] For the reduced solution of untreated MPC (Brix: 5%), the area value of nonanal based on the SPME method was set to 1, and the rate of change (relative value) of the area value of nonanal based on the SPME method was calculated for the adjusted solution (Brix: 5%) of the MPC concentrated solution (NF membrane, 1.2 times) and the reduced solution (Brix: 5%) of the MPC powder (NF membrane, 1.2 times), and is shown in Figure 2.

[0096] According to Fig. 2, in the adjusted solution (Brix: 5%) of the concentrated solution of MPC (NF membrane, 1.2 times), the nonanal content was almost unchanged (changed (increased) by 2%) compared to the reduced solution of untreated MPC (Brix: 5%). Also, according to Fig. 2, in the reduced solution (Brix: 5%) of the MPC powder (NF membrane, 1.2 times), the nonanal content was almost unchanged (changed (increased) by 15%) compared to the reduced solution of untreated MPC (Brix: 5%).

[0097] For the untreated reduced solution of MPC (Brix: 5%), the area value of pentanal based on the SPME method was set to 1, and the rate of change (relative value) of the area value of pentanal based on the SPME method was calculated for the adjusted solution (Brix: 5%) of the MPC concentrated solution (NF membrane, 1.2 times) and the reduced solution (Brix: 5%) of the MPC powder (NF membrane, 1.2 times), and is shown in Figure 3.

[0098] According to Fig. 3, in the adjusted solution (Brix: 5%) of the concentrated solution of MPC (NF membrane, 1.2 times), the pentanal content was almost unchanged (changed (decreased) by 3%) compared to the reduced solution of untreated MPC (Brix: 5%). Also, according to Fig. 3, in the reduced solution (Brix: 5%) of the powder of MPC (NF membrane, 1.2 times), the pentanal content was almost unchanged (changed (increased) by 17%) compared to the reduced solution of untreated MPC (Brix: 5%).

[0099] For the untreated reduced solution of MPC (Brix: 5%), the area value of pentanol based on the SPME method was set to 1, and the rate of change (relative value) of the area value of pentanol based on the SPME method was calculated for the adjusted solution (Brix: 5%) of the MPC concentrated solution (NF membrane, 1.2 times) and the reduced solution (Brix: 5%) of the MPC powder (NF membrane, 1.2 times), and is shown in Figure 4.

[0100] According to Fig. 4, in the adjusted solution (Brix: 5%) of the concentrated solution of MPC (NF membrane, 1.2 times), the pentanol content changed (decreased) by 32% compared to the reduced solution of untreated MPC (Brix: 5%). Also, according to Fig. 4, in the reduced solution (Brix: 5%) of the MPC powder (NF membrane, 1.2 times), the pentanol content hardly changed (changed (decreased) by 5%) compared to the reduced solution of untreated MPC (Brix: 5%).

[0101] From the above results, it was found that when a high-protein milk fluid is prepared from a high-protein milk raw material and this high-protein milk fluid is concentrated using a nanofiltration membrane, various aroma components are changed in various ways. In particular, when a high-protein milk fluid is prepared from a high-protein milk raw material and this high-protein milk fluid is concentrated using a nanofiltration membrane, dimethyl disulfide is released. It was found that the concentration of β-glucose significantly changed (decreased).

[0102] Test Example 4: Changes in nutritional content during the concentration process of milk protein concentrate (MPC) using nanofiltration (NF) membranes (pilot plant scale experiment) [1] In this test, similarly to Test Example 2, a reduced liquid (milk fluid) (total solids content: 10% by mass) of a dairy raw material (MPC) (MPC4882, Fonterra) was concentrated with a nanofiltration membrane to prepare a concentrated MPC liquid (NF membrane) at a concentration equivalent to 1.2 times the concentration ratio of the refractive index sugar content, and the MPC concentrated liquid after the nanofiltration membrane concentration process was spray-dried to obtain MPC powder. The representative nutritional components (total solids, lipids, proteins, carbohydrates (sugar), ash) of the reduced liquid (milk fluid) of MPC before the nanofiltration membrane concentration process and the obtained MPC powder were evaluated (analyzed) as described in (1) to (5) below, and the change ratio of nutritional components (degree of loss of nutritional components) of the MPC powder after the nanofiltration membrane concentration process was confirmed relative to the reduced liquid (milk fluid) of MPC before the nanofiltration membrane concentration process. The MPC powder was measured as a reduced liquid (5% by weight) by the following specified analytical method.

[0103] (1) The total solids concentration of the MPC reduction solution (milk fluid) and the MPC powder was determined by weighing a sample (weight: approximately 3 g) onto an aluminum weighing dish (bottom diameter: approximately 50 mm), evaporating most of the moisture from the sample on a hot plate if necessary, and then keeping the sample in a dryer (temperature: 98-100°C) until it reached a constant weight, and measuring the weight of the sample before and after these treatments.

[0104] (2) The lipid concentrations of the MPC reconstituted solution (milk fluid) and the MPC powder were determined by measurement using the Gerber method (see “2. Lipids (3) Gerber method” in “Attached Methods of Analysis of Nutritional Components, etc.”, which corresponds to the details of the method listed in Column 3 of Appendix 9 of the Food Labeling Standards (Cabinet Office Ordinance No. 10 of 2015)).

[0105] (3) The protein concentrations of the MPC reconstituted solution (milk fluid) and the MPC powder were determined by measurement using the Lowry method (see "Quantitative Method of Protein I", Chemistry and Biology, Vol. 4, No. 1, 1966, pp. 37-44).

[0106] (4) The ash concentration of the MPC reduction liquid (milk fluid) and the MPC powder was determined by weighing a sample (weight: approximately 3 g) into a crucible (bottom diameter: approximately 10 mm), evaporating most of the moisture from the sample on a hot plate, and then holding the sample in an electric furnace (temperature: 550-600°C) until it reached a constant weight.

[0107] (5) The carbohydrate (sugar) concentrations of the MPC reconstituted liquid (dairy fluid) and MPC powder were determined by subtracting the lipid, protein, and ash concentrations from the total solids concentrations of the MPC reconstituted liquid and MPC powder.

[0108] [Test Results] The reduced solution (5% by weight) of MPC (milk fluid) before the nanofiltration membrane concentration process and the reduced solution (5% by weight) of the MPC powder obtained above (after the nanofiltration membrane concentration process) were analyzed by the above-mentioned specified analytical method to confirm the rate of change in nutritional components (total solids, lipids, proteins, carbohydrates (sugars), ash) after nanofiltration membrane treatment compared to before, and the results are shown in Figure 5.

[0109] According to FIG. 5, the percentage change in total solids of the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 2% decrease (almost no change).

[0110] According to Figure 5, compared to the MPC reconstituted liquid (high protein dairy fluid before nanofiltration membrane treatment), In contrast, the lipid change rate for MPC powder (a solid, high-protein dairy ingredient after nanofiltration membrane processing) increased by 1% (almost no change).

[0111] According to FIG. 5, the percentage change in protein in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 3% (almost no change).

[0112] According to FIG. 5, the percentage change in carbohydrates (sugar) in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 22% decrease.

[0113] According to FIG. 5, the percentage change in ash content of MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 2% (almost no change).

[0114] Test Example 5: Changes in salt content during the concentration process of milk protein concentrate (MPC) using nanofiltration (NF) membranes (pilot plant scale experiment) [1] In this test, similarly to Test Example 2, a reduced solution (milk fluid) (total solids content: 10% by mass) of a milk raw material (MPC) (MPC4882, Fonterra) was concentrated with a nanofiltration membrane to prepare a concentrated solution (NF membrane) of MPC at a concentration equivalent to 1.2 times the concentration ratio of the refractive index, and the MPC concentrated solution after the nanofiltration membrane concentration process was spray-dried to obtain MPC powder. The MPC reduced solution (milk fluid) before the nanofiltration membrane concentration process and the obtained MPC powder were evaluated (analyzed) for representative salt components (Na, K, Mg, Ca, Cl, P) as described in (1) and (2) below, and the change ratio of salt components in the MPC powder after the nanofiltration membrane concentration process (degree of loss of salt components) relative to the MPC reduced solution (milk fluid) before the nanofiltration membrane concentration process was confirmed. The MPC powder was measured as a reduced solution (5% by weight) by the following specified analytical method.

[0115] (1) The concentrations of sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), and phosphorus (P) in the MPC reduced solution (milk fluid) and MPC powder were determined by measurement using inductively coupled plasma (ICP) atomic emission spectrometry (see “10. Potassium (3) Inductively Coupled Plasma Atomic Emission Spectroscopy,” “11. Calcium (3) Inductively Coupled Plasma Atomic Emission Spectroscopy,” “16. Sodium (equivalent to salt) (3) Inductively Coupled Plasma Atomic Emission Spectroscopy,” and “21. Phosphorus (3) Inductively Coupled Plasma Atomic Emission Spectroscopy” in the “Attachment: Analytical Methods for Nutritional Components, etc.”, which correspond to the details of the method set out in Column 3 of Appendix 9 of the Food Labeling Standards (Cabinet Office Ordinance No. 10 of 2015)).

[0116] (2) The chlorine (Cl) concentrations in the MPC reduction solution (milk fluid) and in the MPC powder were determined by a rotating electrode polarographic method.

[0117] [Test Results] The reduced solution (5 wt%) of MPC (milk fluid) before the nanofiltration membrane concentration process and the reduced solution (after the nanofiltration membrane concentration process) of the MPC powder obtained above (after the nanofiltration membrane concentration process) were examined for the rate of change in salt components (Na, K, Mg, Ca, Cl, P) after nanofiltration membrane treatment compared to before, using the specified analytical method described above. The results are shown in Figure 6.

[0118] According to FIG. 6, the change rate of Na in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 2% decrease (almost no change).

[0119] According to FIG. 6, the percentage change in K for the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 5% decrease (almost no change).

[0120] According to FIG. 6, the percentage change in Mg in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 1% (almost no change).

[0121] According to FIG. 6, the change rate of Ca in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 5% (almost no change).

[0122] According to FIG. 6, the percentage change in Cl in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 47% decrease.

[0123] According to Figure 6, the percentage change in P for MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was an increase of 2% (almost no change).

[0124] Test Example 6: Concentration process of reconstituted milk protein concentrate (MPC) solution (high protein milk fluid) using nanofiltration membrane (NF membrane) 2 [2] The study was carried out as follows. (6-1) A dairy raw material (MPC) (MPC6631, Fonterra) different from that in Test Example 2 was dissolved in warm water (60°C) to prepare 60 kg of MPC reconstituted liquid (dairy fluid) (total solid content: 10% by mass, protein content: 8% by mass). (6-2) The reduced solution of MPC (10°C) was filtered through a nanofiltration membrane (NF245-3838 / 30-FF, DOW Water & Process Solutions, membrane area: 7.5 m 2The MPC concentrate (NF membrane) was prepared at a concentration equivalent to a 1.2-fold concentration ratio of refractive index (Brix, measured value by a saccharometer) while concentrating using a nanofiltration membrane (×1). (The untreated MPC reduced solution had a Brix of 10.6%, while the MPC concentrated solution (NF membrane, 1.2-fold) had a Brix of 13.2%.) When the MPC reduced solution (total solids content: 10% by weight, protein content: 8% by mass) was concentrated using a nanofiltration membrane, the average permeation flow rate was approximately 5.0 kg / m at Brix concentration ratios of 1 to 1.2. 2 / h. (6-3) The concentrated solution of MPC (NF membrane, 1.2 times) was spray-dried (air supply temperature: 180°C, exhaust temperature: 80°C) to prepare MPC powder (NF membrane, 1.2 times). (6-4) The MPC concentrated solution (NF membrane, 1.2 times) was adjusted (diluted) to the same Brix as the reduced solution of untreated MPC to prepare an adjusted solution of MPC concentrated solution (NF membrane, 1.2 times) (Brix: 7%), while MPC powder (NF membrane, 1.2 times) was dissolved to the same Brix as the reduced solution of untreated MPC to prepare a reduced solution of MPC powder (NF membrane, 1.2 times) (Brix: 7%).

[0125] A panel of five experts confirmed the flavor of the reduced liquid (Brix: 7%) of untreated MPC and the reduced liquid (Brix: 7%) of MPC powder (NF membrane, 1.2 times) obtained by steps (6-1) to (6-4) above.

[0126] From the results of the above flavor analysis, all five members of the expert panel stated that the MPC powder (Brix: 7%) obtained by the above steps (6-1) to (6-4) had an improved refreshing feeling and less protein odor and reduced odor compared to the untreated MPC reduced liquid (Brix: 7%). Therefore, it was found that even if a different dairy ingredient was used than that in Test Example 2, the same effect as in Test Example 2 was obtained.

[0127] Test Example 7: Changes in aroma components during the concentration process of a reconstituted milk protein concentrate (MPC) solution (high-protein dairy fluid) using a nanofiltration membrane (NF membrane) [2] In this test, the changes in aroma components (flavor substances) of the reduced liquid of untreated MPC and the reduced liquid of MPC powder (NF membrane) prepared in Test Example 6 (MPC (MPC6631, Fonterra) was used as the dairy raw material) were evaluated. (7-1) As samples for measuring aroma components, a reduced solution (Brix: 5%) of untreated MPC and a reduced solution (Brix: 5%) of MPC powder (NF membrane, 1.2 times) were prepared (the refractive index of each sample was adjusted to 5%). These samples (volume: 8 mL) and sodium chloride (weight: 3 g) were then placed in vials (volume: 20 mL), and methyl isobutyl ketone (MIBK) was added as an internal standard substance and the vials were sealed. (7-2) The vial was heated at 60°C for 40 minutes. (7-3) The “aroma components” in the headspace of a vial were extracted using a solid-phase microfiber (50 / 30 μm DVB / CAR / PDMS). (7-4) The solid-phase microfiber was analyzed using a gas chromatograph mass spectrometer (GC / MS, column: DB-WAX UI). (7-5) The area values ​​of the aroma components were determined by solid-phase microextraction (SPME), and the behavior of the changes in the aroma components accompanying the nanofiltration membrane concentration process was evaluated by the ratio (relative value) of the change in the aroma components after the nanofiltration membrane concentration process to the ratio before the nanofiltration membrane concentration process. Here, the solid-phase microextraction method is a technology that can analyze volatile aroma components quickly and with high sensitivity.

[0128] The following were selected as evaluation items for aroma components: dimethyldisulfide (DMDS, an indicator of protein deterioration), nonanal (an indicator of lipid deterioration), pentanal (an indicator of pasture odor), 1-pentanol (an indicator of pasture odor), and aminoacetophenone (2-aminoacetophenone, an indicator of alkaline casein odor).

[0129] For the reduced solution of untreated MPC (Brix: 5%), the area value of dimethyl disulfide based on the SPME method was set to 1, and for the reduced solution of MPC powder (NF membrane, 1.2 times) (Brix: 5%), the rate of change (relative value) of the area value of dimethyl disulfide based on the SPME method was calculated and shown in Figure 7.

[0130] According to Figure 7, in the reduced solution (Brix: 5%) of MPC powder (NF membrane, 1.2 times), the dimethyl disulfide content changed (decreased) by 43% compared to the reduced solution (Brix: 5%) of untreated MPC.

[0131] For the reduced solution of untreated MPC (Brix: 5%), the area value of nonanal based on the SPME method was set to 1, and for the reduced solution of MPC powder (NF membrane, 1.2 times) (Brix: 5%), the rate of change (relative value) of the area value of nonanal based on the SPME method was calculated and shown in Figure 8.

[0132] According to FIG. 8, in the reduced solution (Brix: 5%) of MPC powder (NF membrane, 1.2 times), the nonanal content was almost unchanged compared to the reduced solution (Brix: 5%) of untreated MPC (changed (decreased) by 22%).

[0133] For the untreated MPC reduced solution (Brix: 5%), the area value of pentanal based on the SPME method was set to 1, and for the reduced solution (Brix: 5%) of MPC powder (NF membrane, 1.2 times), the rate of change (relative value) of the area value of pentanal based on the SPME method was calculated. This is shown in Figure 9.

[0134] According to FIG. 9, in the reduced solution (Brix: 5%) of MPC powder (NF membrane, 1.2 times), the pentanal content was almost unchanged compared to the reduced solution of untreated MPC (Brix: 5%) (it changed (increased) by 11%).

[0135] For the reduced solution of untreated MPC (Brix: 5%), the area value of pentanol based on the SPME method was set to 1, and for the reduced solution of MPC powder (NF membrane, 1.2 times) (Brix: 5%), the rate of change (relative value) of the area value of pentanol based on the SPME method was calculated and shown in Figure 10.

[0136] According to FIG. 10, in the reduced solution (Brix: 5%) of MPC powder (NF membrane, 1.2 times), the pentanol content was almost unchanged compared to the reduced solution (Brix: 5%) of untreated MPC (changed (increased) by 26%).

[0137] For the reduced solution of untreated MPC (Brix: 5%), the area value of aminoacetophenone based on the SPME method was set to 1, and for the reduced solution of MPC powder (NF membrane, 1.2 times) (Brix: 5%), the rate of change (relative value) of the area value of aminoacetophenone based on the SPME method was calculated and shown in Figure 11.

[0138] According to FIG. 11, in the reduced solution (Brix: 5%) of MPC powder (NF membrane, 1.2 times), the aminoacetophenone content was almost unchanged compared to the reduced solution (Brix: 5%) of untreated MPC (changed (decreased) by 40%).

[0139] From the above results, it was found that when a high-protein milk fluid is prepared from a high-protein milk raw material and this high-protein milk fluid is concentrated using a nanofiltration membrane, various aroma components change in various ways. In particular, it was found that when a high-protein milk fluid is prepared from a high-protein milk raw material and this high-protein milk fluid is concentrated using a nanofiltration membrane, dimethyl disulfide is obviously changed (decreased).

[0140] Test Example 8: Changes in nutritional content during the concentration process of milk protein concentrate (MPC) using nanofiltration (NF) membranes (pilot plant scale experiment) [2] In this test, similarly to Test Example 2, a reduced liquid (milk fluid) (total solids content: 10% by mass) of a dairy raw material (MPC) different from Test Example 1 (MPC6631, Fonterra) was concentrated with a nanofiltration membrane to prepare a concentrated MPC liquid (NF membrane) at a concentration equivalent to 1.2 times the concentration ratio of the refractive index sugar content, and the MPC concentrated liquid after the nanofiltration membrane concentration process was spray-dried to obtain MPC powder. The representative nutritional components (total solids, lipids, proteins, carbohydrates (sugar), ash) of the reduced liquid (milk fluid) of MPC before the nanofiltration membrane concentration process and the obtained MPC powder were evaluated (analyzed) as described in (1) to (5) of Test Example 4, and the change ratio of nutritional components (degree of loss of nutritional components) of the MPC powder after the nanofiltration membrane concentration process was confirmed relative to the reduced liquid (milk fluid) of MPC before the nanofiltration membrane concentration process. The MPC powder was measured as a reduced liquid (5% by weight) by the specified analytical method of Test Example 4.

[0141] [Test Results] The reduced solution (5% by weight) of MPC before the nanofiltration membrane concentration process (dairy fluid) and the reduced solution (5% by weight) of the MPC powder obtained above (after the nanofiltration membrane concentration process) were analyzed by the specified analytical method of Test Example 4 to confirm the rate of change in nutritional components (total solids, lipids, proteins, carbohydrates (sugar), ash) after nanofiltration membrane treatment compared to before, and the results are shown in Figure 12.

[0142] According to Figure 12, compared to the MPC reconstituted liquid (high protein dairy fluid before nanofiltration membrane treatment), In comparison, the percent change in total solids of MPC powder (a solid, high-protein dairy ingredient after nanofiltration) was a 1% decrease (almost unchanged).

[0143] According to FIG. 12, the percentage change in lipids in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 24% (almost no change).

[0144] According to FIG. 12, the percentage change in protein in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 2% (almost no change).

[0145] According to FIG. 12, the percentage change in carbohydrates (sugar) in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 19% decrease.

[0146] According to FIG. 12, the percentage change in ash content of MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 2% (almost no change).

[0147] Test Example 9: Changes in salt content during the concentration process of milk protein concentrate (MPC) using nanofiltration (NF) membranes (pilot plant scale experiment) [2] In this test, similarly to Test Example 2, a reduced liquid (milk fluid) (total solids content: 10% by mass) of a milk raw material (MPC) different from Test Example 1 (MPC6631, Fonterra) was concentrated with a nanofiltration membrane to prepare a concentrated MPC liquid (NF membrane) at a concentration equivalent to 1.2 times the concentration ratio of the refractive index, and the MPC concentrated liquid after the nanofiltration membrane concentration process was spray-dried to obtain MPC powder. The MPC reduced liquid (milk fluid) before the nanofiltration membrane concentration process and the obtained MPC powder were evaluated (analyzed) for representative salt components (Na, K, Mg, Ca, Cl, P) as described in Test Example 5 (1) and (2), and the change ratio of salt components in the MPC powder after the nanofiltration membrane concentration process (degree of loss of salt components) relative to the MPC reduced liquid (milk fluid) before the nanofiltration membrane concentration process was confirmed. The MPC powder was measured as a reduced liquid (5% by weight) by the specified analytical method of Test Example 5.

[0148] [Test Results] The reduced solution (5 wt%) of MPC (milk fluid) before the nanofiltration membrane concentration process and the reduced solution (after the nanofiltration membrane concentration process) of the MPC powder obtained above (after the nanofiltration membrane concentration process) were examined for the rate of change in salt components (Na, K, Mg, Ca, Cl, P) after nanofiltration membrane treatment compared to before, using the specified analytical method of Test Example 5, and the results are shown in Figure 13.

[0149] According to FIG. 13, the percentage change in Na in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 4% decrease (almost no change).

[0150] According to FIG. 13, the percentage change in K for MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 1% decrease (almost no change).

[0151] According to FIG. 13, the percentage change in Mg in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 3% (almost no change).

[0152] According to FIG. 13, the change rate of Ca in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 5% (almost no change).

[0153] According to FIG. 13, the change rate of Cl in the MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to the MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) was a 1% decrease (almost no change).

[0154] According to FIG. 13, the percentage change in P for MPC powder (solid high-protein dairy raw material after nanofiltration membrane treatment) compared to MPC reconstituted liquid (high-protein dairy fluid before nanofiltration membrane treatment) increased by 4% (almost no change).

[0155] Test Example 10: Evaluation in coffee beverages The ingredients listed in Table 1 below were mixed, filled into a container, sealed, and then sterilized at 121°C for 20 minutes to produce a milk coffee (coffee) beverage.

[0156] [Table 1]

[0157] The flavor of each of the beverages obtained above was confirmed by a panel of five experts.

[0158] Compared to the coffee beverage containing untreated MPC, the coffee beverage containing the solid MPC (NF membrane, 1.2 times) obtained by the method of the present invention was found to have a higher taste than the coffee beverage containing untreated MPC, according to all five members of the expert panel. It was evaluated that the protein odor and reduced odor were less noticeable, and the pleasant flavor of the coffee was more apparent.

[0159] Although not described in detail as in the case of coffee beverages, gel foods (e.g. pudding), liquid foods (milk beverages, liquid diets, etc.), frozen foods (e.g. ice cream), and solid / powdered foods (powdered beverages, etc.) were also rated as being able to better experience the desirable flavor of each food, just like coffee beverages.

[0160] In other words, the dairy ingredients obtained by the method of the present invention have an improved refreshing taste, and therefore it has been found that it is possible to enhance the protein content of foods while maintaining a desirable flavor and without impairing the original flavor of the foods to which they are mixed.

Claims

[Claim 1] A step of preparing a high-protein milk fluid having a protein content of 60% by mass or more in the total solid content from a milk raw material; concentrating the dairy fluid with a nanofiltration membrane; The concentration ratio of the retentate when the milk fluid is concentrated using a nanofiltration membrane is 1.2 to 1.4 times in terms of refractive index. A method for producing liquid, high-protein dairy ingredients.

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