Fermented milk

Abstract

To provide standing fermented milk that has a high protein content while having a low hardness and a small number of curd particles, and a method of producing the same.SOLUTION: The fermented milk contains more than 3.4 wt.% and less than 7 wt.% of protein, has a hardness of 20 gf or more and 60 gf or less, and contains curd particles of 0 or more and 500 or less per 100 g.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to fermented milk. More specifically, the present invention relates to a static fermented milk containing a high concentration of protein and a method for producing the same.

Background Art

[0002] Since protein is one of the important nutrients, there is a demand for products containing a large amount of protein in fermented milk.

[0003] Patent Document 1 aims to provide a method for producing fermented milk containing a high concentration of protein with excellent flavor and texture. As a solution, when the proportion of protein is 5 to 10% by mass and the total protein is 100%, the protein contained in skim milk powder is 20 to 60% by mass, the protein contained in whey protein concentrate is 20 to 30% by mass, and the protein contained in milk protein concentrate is 20 to 60% by mass. A method for producing fermented milk is disclosed, which is characterized by blending the skim milk powder, the whey protein concentrate, and the milk protein concentrate.

[0004] Patent Document 2 aims to provide a fermented milk having appropriate hardness and viscosity, less syneresis, stable texture, excellent flavor, and being inexpensive, and a method for producing the same. Further, it aims to provide a fermented milk and a method for producing the same, in which fermentation is promoted, the fermentation time is shortened, and the fermented milk has excellent quality as described above. As a solution, a fermented milk having a stable texture, which is obtained by blending 1 to 15% by weight of milk protein concentrate and de-lactosed permeate in a raw material mix, and a method for producing fermented milk are disclosed.

[0005] Patent Document 3 aims to provide a solid yogurt that maintains its shape and water retention and has a good mouthfeel even when the storage conditions deteriorate, such as temperature rise and physical stimulation, during the delivery or storage of the product, and a method for producing the same. The solid yogurt is characterized by containing substantially non-aggregating denatured protein globular particles or aggregates thereof and gelatin. In a method for producing yogurt by inoculating and culturing lactic acid bacteria in a milk raw material, a step of adding substantially non-aggregating denatured protein globular particles or aggregates thereof and gelatin is provided before or after the culturing step. A method for producing a solid yogurt is disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in addition to the fermented milk and its production method disclosed in Patent Documents 1 to 3, there has been a demand for a novel static fermented milk that is high in protein, has low hardness, and has few curd particles, and a method for producing the same. From the above, an object of the present invention is to provide a novel high-protein static fermented milk and a method for producing the same that have not been available in the past.

Means for Solving the Problems

[0008] The present invention provides an invention including the following configurations as means for solving the above problems. [1] Fermented milk containing more than 3.4% by weight and less than 7% by weight of protein, having a hardness of 20 gf or more and 60 gf or less, and having 0 or more and 500 or less curd particles per 100 g. [2] A process for adjusting the protein content so that the protein in the fermented milk exceeds 3.4% by weight and is less than 7% by weight, and a process for adjusting the amount of microparticulated whey protein so that it is 10% by weight or more and 80% by weight or less based on the protein, a method for producing fermented milk comprising these steps. [3] So as to satisfy at least one of the following conditions (a), (b), and (c): (a) The total protein content is 3.4% by weight or more and less than 7.0% by weight, (b) The protein content derived from microparticulated whey protein is 0.01% by weight or more, (c) The protein content derived from microparticulated whey protein relative to the total protein content is 0.10 to 0.80, The method for producing fermented milk according to [2], comprising a step of adjusting the total protein content and / or the protein content derived from microparticulated whey protein in the fermented milk.

Effect of the Invention

[0009] According to the present invention, there are provided a static fermented milk having a high protein content, low hardness, and few curd grains, and a method for producing the same.

Modes for Carrying Out the Invention

[0010] (Fermented milk) In the present invention, "fermented milk" refers to fermented milk or milk equivalent or higher in non-fat milk solids such as cow's milk, fermented by any one or a combination of lactic acid bacteria, bifidobacteria, and yeast. When classified by properties and manufacturing methods, fermented milk is divided into 1) static fermented milk, 2) stirred fermented milk, and 3) liquid fermented milk. This 1) static fermented milk is also called hard-type fermented milk and has a pudding-like texture fermented in a retail container. For example, it is manufactured as follows. First, after homogenizing, sterilizing, and cooling the fermentation mix prepared by mixing and dissolving raw materials such as milk, dairy products, and sucrose, inoculate with a lactic acid bacteria starter, fill the container, seal it, and then ferment it in a culture room or fermentation tunnel. Immediately cool it to 10°C or lower when it reaches an appropriate acidity to end the fermentation and obtain the final product. 2) Stirred fermented milk is also called soft-type fermented milk. Add a lactic acid bacteria starter to the fermentation mix, ferment it in a tank, crush the curd, fill it into a container, and obtain the final product. 3) Liquid fermented milk ferments the fermentation mix in the same way as stirred fermented milk, and after crushing the curd, homogenizes it to make it liquid as the final product. In the present invention, among the above, 1) static fermented milk is included.

[0011] The milk and dairy products used as raw materials for fermented milk correspond to "milk" and "dairy products" in the ordinance (Ministry of Health and Welfare Ordinance No. 52 of December 27, 1951) regarding the ingredient standards of milk and dairy products. That is, "milk" refers to raw milk, cow's milk, special milk, raw goat milk, pasteurized goat milk, raw ewe milk, adjusted milk, low-fat milk, non-fat milk, and processed milk, and "dairy products" refer to cream, butter, butter oil, cheese, concentrated whey, ice creams, condensed milk, skimmed condensed milk, unsweetened condensed milk, unsweetened skimmed condensed milk, sweetened condensed milk, sweetened skimmed condensed milk, whole milk powder, skimmed milk powder, cream powder, whey powder, protein concentrated whey powder, buttermilk powder, sweetened milk powder, prepared milk powder, fermented milk, lactic acid bacteria beverages (limited to those containing 3.0% or more of non-fat milk solids), and milk beverages.

[0012] (Protein content) In the present invention, the "high-protein fermented milk" refers to containing more than 3.4% by weight of protein contained in ordinary milk. There is no limit to the protein content of the still-type fermented milk of the present invention, but it is preferably more than 3.4% by weight and less than 7% by weight in terms of reducing the number of curd grains. However, when it is 4% by weight or more and less than 7% by weight, or 5% by weight or more and less than 7% by weight, a still-type fermented milk with high protein but low hardness and few curd grains can be obtained.

[0013] Subsequently, the total protein content and the protein content derived from microparticulated whey protein in the fermented milk will be described. (a) The total protein content is preferably 3.4% by weight or more and less than 7.0% by weight, (b) the protein content derived from microparticulated whey protein is preferably 0.01% by weight or more, and (c) the protein content derived from microparticulated whey protein relative to the total protein content is preferably 0.10 to 0.80. It is preferable to satisfy at least one of the above conditions (a), (b), and (c), more preferably to satisfy two of them, and particularly preferably to satisfy all three of them. Further, (a2) the total protein content is preferably 4.0% by weight or more and less than 7.0% by weight, (b2) the protein content derived from microparticulated whey protein is preferably 0.5% by weight or more, and (c2) the protein content derived from microparticulated whey protein relative to the total protein content is preferably 0.20 to 0.80. It is preferable to satisfy at least one of the above conditions (a2), (b2), and (c2), more preferably to satisfy two of them, and particularly preferably to satisfy all three of them.

[0014] (Hardness) The hardness of the fermented milk of the present invention can be made as desired, but in terms of flavor such as texture and smoothness of the texture, and product transport resistance, the hardness is preferably 20 to 60 gf, more preferably 20 to 55 gf, and even more preferably 20 to 50 gf.

[0015] (Number of curd grains) The card grains of the fermented milk of the present invention are preferably 0 or more and 500 or less, more preferably 0 or more and 450 or less, and even more preferably 0 or more and 400 or less per 100 g of fermented milk in that the card grains are not easily noticeable when mixed with fruit sauce, jam, etc.

[0016] (Fat content) Although there is no particular limitation on the fat content of the fermented milk of the present invention, since the present invention relates to fermented milk with high protein, it is suitable for low-fat types (about 2% by weight or less) or fat-free types (substantially 0% by weight) of fermented milk in relation to the total solids of the fermented milk.

[0017] (Method for measuring hardness) The hardness of the fermented milk of the present invention is defined by the maximum load of the fermented milk. The maximum load can be measured by a two-pass penetration test on the fermented milk using a texture analyzer. Specifically, the maximum load of the fermented milk can be measured under the conditions of applying a sample adjusted to 10°C to a texture analyzer, Test Speed: 1 mm / s, Penetration distance: 10 mm, Fixture: Resin cylindrical probe with a diameter of 16 mm and a height of 25 mm, Mode: Compression. The size of the sample only needs to have a height of 10 mm or more of the penetration distance and a diameter of 16 mm or more.

[0018] (Method for measuring the number of card grains) The number of card grains of the fermented milk of the present invention can be measured by the following procedure. Collect 100 g of fermented milk in a cup and stir it at 200 rpm for 1 minute with a stirrer equipped with a motor and four blades. Adjust the fermented milk after stirring to 25 g, which is 1 / 4 of the original amount, and add tap water to make the total amount 200 g. Stir this with a magnetic stirrer at 400 rpm for 30 seconds, filter it through a sieve with a 1 mm opening, and count the number of grains trapped on the sieve. Multiply the number of grains obtained by measurement by 4 to obtain the number of card grains.

[0019] (Manufacturing method) (Raw materials) (Micronized whey protein) The fermented milk of the present invention contains microparticulated whey protein. The microparticulated whey protein refers to a precipitate fraction obtained by subjecting a solution containing whey protein to a physicochemical treatment in which the whey protein aggregates and then performing centrifugation. Known commercially available milk protein materials may be used as the microparticulated whey protein. Examples of commercially available microparticulated whey protein materials include Simpless100 (manufactured by CPKelko), WPC550 (manufactured by Fonterra), and the like. Alternatively, it may be prepared from a solution containing whey protein using a known method. For example, it can be adjusted by the method described in International journal of food science & technology, 34(5-6), p523-525. The degree of denaturation of the whey protein contained in the microparticulated whey protein material is 70% or more, more preferably 80% or more, and even more preferably 90% or more. Also, the median diameter of the microparticulated whey protein is preferably 5 μm or less, more preferably 4 μm or less, and most preferably 3 μm or less. Heat treatment and homogenization treatment are performed as necessary so as to obtain such a degree of denaturation and median diameter. The microparticulated whey protein material may be blended so that the amount of protein derived from the microparticulated whey protein material is contained in the stationary fermented milk at 0.01% by weight or more, preferably 0.5% by weight or more, more preferably 1% by weight or more, even more preferably 2% by weight or more, and even more preferably 3% by weight or more. Also, the ratio of the amount of microparticulated whey protein to the total protein contained in the stationary fermented milk of the present invention is preferably 0.10 to 0.80, more preferably 0.20 to 0.70, and most preferably 0.30 to 0.60 from the viewpoint of reducing the number of curd grains. When adjusting the hardness, WPI (Whey Protein Isolate: WPI) and / or WPC (Whey Protein Concentrate: MPC) can be added. If the blending amount is less than 1% by weight as the protein amount with respect to the fermented milk, it is possible to suppress the decrease in hardness without causing an increase in the excessive number of curd grains.

[0020] (Manufacturing process) A specific embodiment of the method for producing the fermented milk of the present invention will be described below. Weigh and dissolve a predetermined amount of milk raw materials such as raw milk, skim milk powder, MPC (Milk Protein Concentrate: MPC), WPC, WPI, and microparticulated whey protein, as well as other raw materials generally used in the production of fermented milk, and then perform homogenization treatment and sterilization treatment. There is no specific designation for the order of the homogenization treatment and the sterilization treatment. The conditions for homogenization can be exemplified by a homogenization pressure of 50 to 500 kg / cm at a temperature of 50 to 70 °C, and the conditions for sterilization can be exemplified by holding at a temperature of 80 to 95 °C for 2 seconds to 10 minutes, but it is not limited thereto. 2 The holding time is not limited to this. Add lactic acid bacteria to the cooled raw material liquid (mix) and fill it into a container. When adding lactic acid bacteria, as fermentation conditions, fermentation at 30 to 40 °C for 3 to 20 hours and the end point of fermentation when the lactic acid acidity of the mix reaches 0.7 to 1.3% can be exemplified. The lactic acid bacteria used for fermentation can be exemplified by Lactobacillus bulgaricus (L. bulgaricus), Streptococcus thermophilus (S. thermophilus), etc., but there is no particular limitation as long as it is a lactic acid bacteria starter commonly used in the production of fermented milk. After the fermentation is completed, the container is cooled to 10 °C or lower to obtain a still-type fermented milk.

[0021] (Degree of denaturation) The degree of denaturation of whey protein can be measured by the following method. Dispense 0.4 g of the sample, 0.8 g of distilled water at 40°C, and 40 μL of 10% by volume acetic acid into a microtube. After stirring well, hold for 10 minutes. Then, dispense 40 μL of 1 M sodium acetate and 0.72 g of distilled water into the microtube and stir well again. After leaving it for 1 hour, centrifuge at 3000 g for 5 minutes. Consider the amount of insoluble whey protein precipitated by this treatment as the denatured whey protein, and the amount of soluble whey protein contained in the supernatant as the undenatured whey protein. Also, after replacing 10% by volume hydrochloric acid and 1 M sodium acetate with distilled water and performing the above treatment, consider the amount of soluble protein contained in the supernatant as the total amount of whey protein. At this time, the degree of denaturation of the whey protein contained on a whey protein basis was expressed by the following formula. For protein quantification, a BCA Protein Assay Kit manufactured by ThermoFisher was used. Degree of denaturation = denatured whey protein / total whey protein = (1 - whey protein in supernatant) / total whey protein)

[0022] (Median diameter) The median diameter of the micronized whey protein can be measured using a device for measuring particle size distribution, such as a laser diffraction particle size distribution analyzer, a laser diffraction / scattering particle size distribution analyzer, an image analysis particle size distribution analyzer, a precision particle size distribution analyzer, a real-time zeta potential / nanoparticle size analyzer, a dynamic light scattering (DLS) particle size distribution analyzer, an analytical ultracentrifugation system, etc. The particle diameter corresponding to 50% of the cumulative distribution curve based on the obtained volume is called the median diameter, and is also referred to as the so-called 50% particle diameter, 50% diameter, d50, etc.

Examples

[0023] Next, the present invention will be specifically described by showing examples. However, the present invention is not to be construed as being limited to the examples.

[0024] (Preparation of micronized whey protein) The UF concentrate of cheddar cheese whey was heated and sheared by the method described in International journal of food science & technology, 34(5-6), p523-525. Then, the obtained whey suspension was spray-dried to obtain a powder of microparticulated whey protein (hereinafter also referred to as MPW in the table). The whey protein concentration of the powder of microparticulated whey protein was 79%, the degree of whey protein denaturation was 90%, and the median diameter of the whey protein was 1.5 μm. The obtained powder of microparticulated whey protein was used in the following tests.

[0025] (Examples 1 to 8, Comparative Examples 1 to 2) According to the formulations shown in Table 1, the static fermented milks of Examples 1 to 8 and Comparative Examples 1 to 2 were produced by the following preparation method. The raw materials were mixed and dissolved with formulated water at 65°C using a homomixer to prepare a mix. The mix was reheated to 65°C and homogenized at a homogenization pressure of 140 kg / cm 2 and then heat-sterilized at 95°C for 30 seconds. Then, it was cooled to 40°C, 1.5% by weight of Lactobacillus bulgaricus and 0.15% by weight of Streptococcus thermophilus were added, and the container was filled. The container filled with the mix was fermented in a fermentation chamber set at 40°C, and when the acidity reached 1.00%, it was cooled to 5°C to obtain a static fermented milk. In addition, in all of Examples 1 to 8 and Comparative Examples 1 to 2, the lipid was 0.5% by weight or less.

[0026]

Table 1

[0027] Table 2 shows the characteristics of Examples 1 to 8 and Comparative Examples 1 to 2. In addition, as the characteristic values of the static fermented milk, the hardness and the number of curd grains of the static fermented milk at a product temperature of 10°C one week after preparation were used.

[0028]

Table 2

[0029] In Examples 1 to 8, the hardness was 20 to 60 gf, and the number of curd particles was 500 particles / 100 g or less, resulting in a structure with appropriate hardness and suppressed increase in the number of curd particles. In Comparative Example 1, the hardness was 60 gf or more, and the structure was hardened. In Comparative Example 2, the mixture did not gel and did not become a set-type fermented milk. That is, the set-type fermented milk characterized in that the total protein is 3.4% or more and less than 7.0%, the protein derived from microparticulated whey protein is 0.01% or more, and the amount of protein derived from microparticulated whey protein relative to the total protein amount is 0.10 to 0.80 had appropriate hardness and the number of curd particles was suppressed.

Claims

1. containing 4% by weight or more and less than 7% by weight of protein, having a hardness of 20 gf or more and 60 gf or less, and 0 to 500 card grains per 100 g, wherein the protein contains microparticulated whey protein having a median diameter of 5 μm or less, a static fermentation milk characterized by the above.

2. a step of adjusting the protein content so that the protein in the fermentation milk is 5% by weight or more and less than 7% by weight; a step of adjusting the amount of microparticulated whey protein so that the microparticulated whey protein is 10% by weight or more and 80% by weight or less based on the protein; a method for producing a static fermentation milk, characterized by comprising: the production method wherein the median diameter of the microparticulated whey protein is 5 μm or less.

3. Furthermore, a step of adjusting the protein content so as to satisfy that the protein amount derived from the microparticulated whey protein in the fermentation milk is 0.01% by weight or more; The method for producing a static fermentation milk according to claim 2, characterized by comprising the above.

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