Milk powder

Abstract

To provide versatile milk powders which have a natural flavor and less limitation in application as food raw materials.SOLUTION: Provided are milk powders in which the amino acid content is any one of the following (1) to (4): (1) containing 400 μg or more and 720 μg or less of glutamic acid per 1 g of the milk powders; (2) containing 40 μg or more and 70 μg or less of aspartic acid per 1 g of the milk powders; (3) containing 16 μg or more and 90 μg or less of tyrosine per 1 g of the milk powders; and (4) containing glutamic acid, aspartic acid, and tyrosine, wherein the total amount of the three is 456 μg or more and 880 μg or less per 1 g of the milk powders.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to powdered milk, and in particular to whey powder with excellent flavor. [Background technology]

[0002] Powdered milk products, such as skim milk powder made from raw milk and whey powder (also called whey powder), a by-product of natural cheese production, are widely used as ingredients in beverages, yogurt, confectionery, bread, protein-fortified foods, and more. Generally, the flavor of powdered milk comes from the flavor of the raw milk before it is powdered, and may contain a grass smell derived from feed or a cooked or oxidized smell that occurs during the manufacturing process. Furthermore, the flavor of whey powder is derived from the flavor of the liquid whey before powderization, and the flavor of the liquid whey is affected by the type of cheese produced. Some types of cheese have an undesirable flavor (off-flavor) due to the lactic acid bacteria or mold used in their production, which can cause the desirable flavors inherent in whey, such as milkiness and sweetness, to be lost. Therefore, in order to increase the versatility of use as a food ingredient, it is desirable to minimize such off-flavors in powdered milk.

[0003] Patent Document 1 discloses a method for producing a flavorful whey powder in which the unpleasant whey odor from a whey solution has been reduced, by subjecting the whey solution to diafiltration treatment using a nanofiltration membrane. Patent Document 2 discloses a method for reducing the odor unique to milk containing whey and producing hygienic and flavorful drinking milk, in which raw milk is brought into contact with an adsorbent resin and then heat-sterilized by a direct heating method. Patent Document 3 discloses a method for producing a condensed milk-like whey composition with good physical properties and flavor, without causing burning on the heating surfaces of a sterilizer or concentrator, by heat-sterilizing and concentrating a whey preparation obtained by adding auxiliary ingredients containing sucrose to whey that has been previously heat-treated at high temperatures. However, the techniques of Patent Document 1 and Patent Document 2 require special processing steps using nanofiltration membranes, adsorptive resins, etc., and the technique of Patent Document 3 requires a separate addition step because sucrose is added. Furthermore, there are problems in that the use of the product as a food ingredient is limited because other ingredients are added. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-145995 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-291119 [Patent Document 3] Re-tabled publication 2011 / 027733 Summary of the Invention [Problem to be solved by the invention]

[0005] In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a versatile milk powder that has a natural flavor and is less restricted in its use as a food ingredient. [Means for solving the problem]

[0006] The inventors discovered that by adjusting the amino acid concentration of raw milk to produce powdered milk, it is possible to produce powdered milk that has a strong sweetness, a milky flavor, and has improved unpleasant flavors such as astringency, and thus completed the present invention. That is, the present invention has the following configuration. <1> Powdered milk having an amino acid content of any one of the following (1) to (4): (1) Contains 400 μg or more but not exceeding 720 μg of glutamic acid per 1 g of powdered milk (2) Contains 40 μg or more and 70 μg or less of aspartic acid per 1 g of powdered milk (3) Contains tyrosine in an amount of 16 μg or more and 90 μg or less per gram of powdered milk. (4) Contains glutamic acid, aspartic acid, and tyrosine, with the total amount of these being between 456 μg and 880 μg per gram of powdered milk. <2> The milk powder is whey powder. <1> The milk powder described in <3> <1> or <2> A food or drink containing the powdered milk described in the above. <4> A method for producing fermented milk, comprising: Adding whey powder having an amino acid content of any one of the following (1) to (4) to the fermentation mix; (1) Contains 400 μg or more but not exceeding 720 μg of glutamic acid per 1 g of powdered milk (2) Contains 40 μg or more and 70 μg or less of aspartic acid per 1 g of powdered milk (3) Contains tyrosine in an amount of 16 μg or more and 90 μg or less per gram of powdered milk. (4) Contains glutamic acid, aspartic acid, and tyrosine, with the total amount of these three acids being between 456 μg and 880 μg per 1 g of powdered milk. a step of adding a lactic acid bacteria starter to the fermentation mix to which the whey powder has been added and fermenting the mixture; A method for producing fermented milk comprising: [Effects of the Invention]

[0007] According to the present invention, it is possible to provide powdered milk that has a strong sweetness, a milky flavor, and a reduced astringency. Furthermore, since the powdered milk of the present invention does not contain any additional food ingredients that are not originally contained in the raw milk, it can be added to a variety of foods and used without being limited to the foods to which it is to be applied. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Milk powder) The milk powders of the present invention refer to powdered milks obtained by drying liquid raw milk. Examples of liquid raw milk include whey, raw milk, cow's milk, skim milk, partially skimmed milk, non-fat milk, low-fat milk, unadjusted milk, concentrated milk, and condensed milk. The liquid raw milk of the present invention also includes reconstituted milk, such as whole milk powder, skim milk powder, whey powder, whey protein concentrate (WPC), and whey protein isolate (WPI) dissolved in water. Of these, the present invention preferably uses whey (liquid) as the raw milk, and more preferably non-reconstituted whey (liquid). Furthermore, whey powder is preferred as the milk powder of the present invention.

[0009] Whey powder refers to "whey powder" as defined in the Ministerial Ordinance on Milk, Milk, and Related Products. Specifically, it refers to whey (also called whey serum) obtained by fermenting milk with lactic acid bacteria or by adding enzymes or acids to milk, after removing almost all of the water and turning it into a powder. Whey is typically obtained as a by-product in the cheese or casein manufacturing process and can be classified into sweet whey and acid whey. In the present invention, either sweet whey or acid whey can be used as raw milk. In this specification, unless otherwise specified, whey refers to liquid whey, and may be referred to as "liquid whey" or "liquid whey" for confirmation or in contrast to powdered whey (sometimes called whey powder).

[0010] In the milk powder of the present invention, the concentration of one or more amino acids from the group consisting of glutamic acid, aspartic acid, and tyrosine is preferably adjusted, more preferably two or more, and even more preferably all three. The amino acids may be salts or derivatives as long as they can impart the milky taste and sweetness of the present invention. In consideration of solubility in water, salts of glutamic acid and aspartic acid include sodium salts, potassium salts, magnesium salts, and hydrochlorides. In consideration of solubility in water, N-acetyltyrosine is preferred as tyrosine. The types and contents of amino acids prepared in the milk powder of the present invention are shown below. When using a salt or derivative of an amino acid, the content converted to the corresponding amino acid content may be used. The milk powder of the present invention preferably contains glutamic acid in an amount of 400 μg or more and 720 μg or less per gram of milk powder, and more preferably 600 μg or more and 720 μg or less. The milk powder of the present invention preferably contains 40 μg or more and 70 μg or less of aspartic acid per 1 g of milk powder, and more preferably 50 μg or more and 70 μg or less. The milk powder of the present invention preferably contains tyrosine in an amount of 16 μg to 90 μg per gram of milk powder, more preferably 70 μg to 90 μg. Furthermore, when N-acetyl tyrosine is used as tyrosine, the milk powder preferably contains N-acetyl tyrosine in an amount of 20 μg to 110 μg per gram of milk powder, more preferably 70 μg to 110 μg. The milk powder of the present invention contains glutamic acid, aspartic acid, and tyrosine, and the total amount of the three acids is preferably 456 μg or more and 880 μg or less per 1 g of the milk powder, and more preferably 700 μg or more and 880 μg or less. The content of each amino acid in powdered milk can be measured by a method used in the food industry that is well known to those skilled in the art. The milk powders of the present invention have the same components as common milk powders, with protein 5.0% to 40.0%, lipid 0.01% to 30.0%, carbohydrates 40.0% to 80.0%, and ash 0.01% to 10.0%. The whey powder of the present invention has the same components as common whey powders, with protein 5.0% to 20.0%, lipid 0.01% to 5.0%, carbohydrates 60.0% to 80.0%, and ash 0.01% to 10.0%. The lipid content of the milk powder of the present invention is preferably 0.5% to 6.0%, more preferably 1.0% to 4.0%, and the lipid content of the whey powder of the present invention is preferably 0.5% to 6.0%, more preferably 2.0% to 5.0%. The ash content of the milk powder of the present invention is preferably 6.0% to 9.0%, more preferably 6.5% to 8.0%, and the ash content of the whey powder of the present invention is preferably 4.0% to 9.0%, more preferably 6.0% to 8.5%.

[0011] (Method of producing powdered milk) The method for producing the milk powder of the present invention is not particularly limited as long as it is a method that can produce a milk powder having the amino acid composition described above. For example, the following method can be exemplified. The production method is characterized by including a step of adjusting the amino acid concentration of liquid raw milk. The amino acid concentration adjustment step may be a step of adjusting the amino acid content of the liquid raw milk when dried to form powdered milk to the amino acid content of the above-mentioned milk powders. In the present invention, the amino acid concentration in raw milk refers to the total concentration of amino acids originally contained in the raw milk and amino acids added from outside. Therefore, in the present invention, the amino acid concentration can be adjusted by either adjusting the raw milk production process to the amino acid content of the present invention or by adding amino acids from outside to the liquid raw milk. Examples of methods for adjusting the amino acid concentration in the raw milk production process include adjusting the desired amino acid concentration in a step of concentrating liquid whey by membrane filtration or by adjusting the type of liquid whey or by mixing different liquid wheys. Furthermore, the amino acids added from outside to the liquid raw milk may be purified amino acids, crude amino acids, or unpurified amino acids containing a large amount of amino acids. Examples of unpurified amino acids include enzymatic hydrolysis of proteins. It is preferable to select amino acids that are highly soluble in water as purified amino acids. Alternatively, liquid amino acids may be added to powdered raw milk such as whey powder, followed by drying to produce powdered milk. One embodiment of the step of adjusting the amino acid concentration of raw milk in the method for producing milk powder of the present invention is a step of adjusting glutamic acid to 400 μg or more and 720 μg or less per 1 g of milk powder. Another embodiment is a step of adjusting the aspartic acid content to 40 μg or more and 70 μg or less per 1 g of powdered milk. Another embodiment is a step of adjusting the tyrosine content to 16 μg or more and 90 μg or less per 1 g of powdered milk. Another embodiment is a step of adjusting the total amount of glutamic acid, aspartic acid, and tyrosine to 456 μg or more and 880 μg or less per 1 g of powdered milk. The amino acid concentration may be adjusted at any time up to the time when the liquid raw milk is dried to obtain a powdered milk powder. The following description will be given taking the case where the raw milk is whey as an example. The steps for producing whey powder from the raw material liquid whey include a step of preparing liquid whey, a step of sterilizing the liquid whey, a step of concentrating the liquid whey, and a step of drying the liquid whey. The timing for adjusting the amino acid concentration of the liquid whey can be before or after the sterilization step, before or after the concentration step, or before or after the drying step. That is, the production may be performed in the following order: after the liquid whey preparation step, the amino acid concentration adjustment step, the sterilization step, the concentration step, and the drying step; after the liquid whey preparation step, the sterilization step, the amino acid concentration adjustment step, the concentration step, and the drying step; or after the whey preparation step, the sterilization step, the concentration step, the amino acid concentration adjustment step, and the drying step. Alternatively, the dried whey powder may be dissolved in a liquid such as water to prepare liquid whey, and then the amino acid concentration may be adjusted. Therefore, according to the production method of the present invention, commercially available whey powder may be dissolved in water or the like to prepare liquid whey, and then the amino acid concentration may be adjusted and dried to improve the flavor of the original whey powder. When cheese whey is used, it is preferable to perform the production in the following order: after the cheese whey preparation step, the amino acid concentration adjustment step, the sterilization step, the concentration step, and the drying step. The amino acid concentration adjustment step is preferably performed by adding amino acids and stirring until dissolved. According to the above-mentioned production method, when whey powder whose flavor has been improved by adjusting the amino acid concentration is used in food production, it has been confirmed that the flavor of the whey powder can be maintained regardless of the amino acid concentration of the food raw material added (see Production Example 1 described below). Therefore, in this respect, the above-mentioned whey powder production method can also be said to be a method for improving whey powder.

[0012] The method for producing milk powder of the present invention preferably includes a step of adjusting the pH in addition to adjusting the amino acid concentration of the liquid raw milk. The adjusted pH is preferably 6.7 to 9.0, and the timing of the pH adjustment is not important. It is more preferably 6.7 to 7.65. The pH can be adjusted, for example, by adding a pH adjuster. Any pH adjuster commonly used in foods may be used, such as trisodium citrate, sodium bicarbonate, sodium hydroxide, or citric acid.

[0013] In the method for producing milk powder of the present invention, the drying step is not limited as long as it is a step that can dry liquid raw milk, the amino acid concentration of which has been adjusted or the amino acid concentration and pH of which have been adjusted, into a powder. Among these, a so-called spray drying step, in which liquid raw milk is sprayed in a heated atmosphere and dried into a powder, is preferred. Furthermore, the sterilization step and concentration step can also be steps that are commonly used in the production of whey powder. In the present invention, conditions for the heat sterilization treatment of liquid whey include a temperature of 100 to 150°C for 1 to 30 seconds. Examples of devices for the heat sterilization treatment include a plate-type heat exchanger, a tubular-type heat exchanger, a steam injection sterilizer, a steam infusion sterilizer, and an electric heating sterilizer.

[0014] According to the method for producing milk powder of the present invention, the flavor of the resulting milk powder can be improved by adjusting the amino acid concentration of the liquid raw milk. Therefore, the method for producing milk powder of the present invention can also be considered a method for improving the flavor of milk powder. It can also be considered a method for controlling (adjusting) the flavor of milk powder. Evaluation criteria for flavor improvement include improved sweetness, improved milkiness, and reduced astringency. The flavor improvement is preferably achieved in one or more evaluation criteria, more preferably in two or more flavor criteria, and most preferably in all flavor criteria. Whether or not flavor has been improved can be determined by comparing the sensory evaluation of expert panelists between drinking or consuming milk powder with an unadjusted amino acid concentration and drinking or consuming milk powder with an amino acid concentration adjusted to the specific range of the present invention. The flavor-improved milk powders of the present invention can be used in the production of various foods and beverages. Therefore, another aspect of the present invention relates to foods and beverages containing the above-mentioned milk powders. They can be used not only in foods and beverages that have previously used milk powders, but also in foods and beverages that could not be used due to the unpleasant flavor of milk powders. In particular, the expanded use of cheese whey, which has a unique cheese-derived odor, is of great significance. Examples of foods and beverages include beverages, fermented foods such as yogurt, confectioneries, bread, noodles such as udon, protein-enriched foods, and supplements. The present invention will be specifically described below based on examples, but the scope of the present invention is not limited thereto. [Example]

[0015] [Examples 1 to 4] The relationship between the flavor and liquid whey with adjusted amino acid concentration was investigated. 1. How to adjust the amino acid concentration of whey The desalted whey powder shown below was reconstituted with water to a concentration of 10%, and the sample solution was cooled to 10°C to adjust the amino acid concentration to the concentration shown below. The amino acid concentration is expressed as the amount of each amino acid per gram of dried whey powder. Example 1 Glutamic acid 695 μg / g Example 2 Aspartic acid 60 μg / g Example 3 N-acetyl tyrosine 98 μg / g (equivalent to tyrosine: 80 μg / g) Example 4: Glutamic acid 695 μg / g, Aspartic acid 60 μg / g, N-acetyltyrosine 98 μg / g The component values ​​of desalted whey powder and the pH when dissolved in water are as follows. % indicates mass % unless otherwise specified. The concentration of each amino acid was measured by reacting the sample with the fluorescent derivatization reagent NBD-F (4-Fluoro-7-nitrobenzofurazan) and then using reverse-phase chromatography.

[0016] <Desalted whey powder composition> Protein 12.3% Fat 1.0% Carbohydrates 78.7% Ash content 6.0% Glutamic acid 386μg / g Aspartic acid 36μg / g N-acetyltyrosine 17μg / g (14μg / g equivalent to tyrosine) pH 6.5

[0017] 2. Sensory evaluation test method Approximately 20 mL of each liquid whey obtained after adjusting the amino acid concentration was dispensed into plastic cups, and six trained expert panelists drank and evaluated the flavor. The flavor evaluation items were "sweetness," "milky flavor," and "astringency." Scoring was based on a score of 0 for a sample with no amino acid concentration adjustment (a sample made by simply dissolving desalted whey powder in water to a concentration of 10%), and relative evaluation was conducted in 0.5-point increments within the range of -3 to +3, and the average score of the six panelists was calculated. Higher scores for "sweetness" and "milky flavor" were considered desirable, while lower scores for "oxidized odor" were considered desirable.

[0018] <Evaluation items> "Sweetness" Sweetness of taste "Milk flavor" - Milky and creamy taste like raw milk "Oxidized odor" Off-flavors such as the odor of deteriorated amino acids and the odor of fatty acids in oils and fats

[0019] <Grade definition> -3 Very weak -2 Slightly weak -1 slightly weaker 0 Neither +1 slightly stronger +2 Slightly strong +3 Very strong

[0020] [Table 1]

[0021] 3.Results Table 1 shows the results of the sensory evaluation of the desalted whey powder (comparison product) and example products 1 to 4 in which the amino acid concentrations were adjusted. The addition of amino acids increased sweetness and milkiness, and suppressed oxidized odor. In particular, the addition of tyrosine resulted in higher evaluation scores than the addition of other amino acids, and the addition of all three amino acids resulted in the highest evaluation score.

[0022] [Example 5] Whey obtained during natural cheese production was used as raw milk, and whey powder was produced by the production method of the present invention and evaluated. 1. Whey powder manufacturing method Liquid whey (pH 6.2) obtained during the natural cheese manufacturing process was defatted and then concentrated three-fold through a nanofiltration process. Defatted fat was added to the whey to achieve a lipid content of 3.0% per solids, and a 12% NaOH solution was added to adjust the pH of the whey to 7.2. After sterilization, concentration, and drying, whey powder was obtained with a lipid content of 3.0%, protein content of 11%, ash content of 7.5%, and the amino acid concentrations shown in Table 2. The obtained whey powder was dissolved in water to a concentration of 10%, and a sensory evaluation was carried out in the same manner as in Example 1, with a score of 0 given to a sample prepared by simply dissolving desalted whey powder in water to a concentration of 10%.

[0023] [Table 2]

[0024] 2. Sensory evaluation test method Approximately 20 mL of each liquid whey obtained after adjusting the amino acid concentration was dispensed into plastic cups, and six trained expert panelists drank and evaluated the flavor. The flavor evaluation items were "sweetness" and "milk flavor." Scoring was based on a relative score of 0, with a score of 0 representing a sample with no amino acid concentration adjustment (a sample made by simply dissolving desalted whey powder in water to a concentration of 10%), and a range of -3 to +3 was used in increments of 0.5 points. The average score of the six panelists was calculated. A higher score is considered more desirable.

[0025] <Evaluation items> "Sweetness" Sweetness of taste "Milk flavor" - Milky and creamy taste like raw milk

[0026] <Grade definition> -3 Very weak -2 Slightly weak -1 slightly weaker 0 Neither +1 slightly stronger +2 Slightly strong +3 Very strong

[0027] 3.Results The milk flavor was rated at 1.5 points, and the sweetness was rated at 1.0 points. This method for producing whey powder involves adjusting the amino acid concentration to the above levels using liquid whey obtained in cheese production. It was found that adjusting the amino acid concentration and pH to 7.2 in this way increases the milk flavor and sweetness compared to commercially available whey powders without adjusting the amino acid concentration.

[0028] [Production Example 1] Production of coffee milk drink 1. Manufacturing method of coffee milk drink The whey powder of Example Product 4 was added to a coffee milk drink at 1.4%. As a control, the whey powder of Comparative Example Product was added to a coffee milk drink at 1.4%.

[0029] 2. Evaluation Method The "milk flavor" and "sweetness" were evaluated according to the method of Example 1.

[0030] 3.Results The milk flavor was 0.8 points and the sweetness was 0.7 points. Therefore, it was found that the milk flavor and sweetness of dairy drinks can be increased by using whey powder with an adjusted amino acid concentration according to the present invention.

[0031] [Production Example 2] Production of low-fat yogurt 1. How to make low-fat yogurt 9.3% commercially available skim milk powder (Megmilk Snow Brand Co., Ltd.), 0.25% commercially available unsalted butter (Megmilk Snow Brand Co., Ltd.), and 1.3% whey powder with a pH of 7.0 obtained in Production Example 1 of Example Product 4 were dissolved in warm water (60°C) and stirred at 8000 rpm for 3 minutes using a TK mixer (Primix Corporation). The resulting intermediate mix 1 was homogenized at 15 MPa using a homogenizer (Sanwa Engineering Co., Ltd.). 3.0 kg of the resulting intermediate mix 2 was weighed out, heated in warm water, and held for 10 minutes after reaching 90°C. The resulting intermediate mix 3 was cooled to 45°C in ice water to prepare the fermentation base. Starters of Bifidobacterium, Lactobacillus bulgaricus, and Streptococcus thermophilus were added to the fermentation base, stirred for 2 minutes, and then placed in an incubator (set at 44°C). When the acidity of the mix (lactic acid acidity) reached 0.70%, the mixture was removed from the incubator to complete fermentation, and then cooled to 10°C to obtain low-fat yogurt. As a control, the low-fat yogurt was prepared using the above desalted whey powder with no amino acid adjustment.

[0032] 2. Evaluation Method The "milk flavor," "sweetness," and "astringency" were evaluated according to the methods of Example 1.

[0033] 3.Results The milk flavor was 0.6 points, the sweetness was 0.6 points, and the astringency was -0.8 points. Therefore, it was found that by using the whey powder of the present invention in which the amino acid concentration is adjusted to a specific range, the milk flavor and sweetness of yogurt can be increased and the astringency can be suppressed.

[0034] The above examples and production examples show that by using powdered milk with an amino acid concentration adjusted to a specific range in foods and beverages, it is possible to increase the sweetness and milk flavor and suppress the astringency compared to conventional powdered milks.

Claims

1. A milk powder having an amino acid content of any one of the following (1) to (4): (1) Contains 400 μg or more but not exceeding 720 μg of glutamic acid per 1 g of powdered milk (2) Contains 40 μg or more and 70 μg or less of aspartic acid per 1 g of powdered milk. (3) Contains tyrosine in an amount of 16 μg or more and 90 μg or less per gram of powdered milk. (4) Contains glutamic acid, aspartic acid, and tyrosine, with the total amount of the three being between 456 μg and 880 μg per 1 g of powdered milk.

2. 2. The milk powder according to claim 1, wherein the milk powder is whey powder.

3. A food or drink comprising the milk powder according to claim 1 or 2.

4. A method for producing fermented milk, comprising: Adding whey powder having an amino acid content of any one of the following (1) to (4) to the fermentation mix; (1) Contains 400 μg or more but not exceeding 720 μg of glutamic acid per 1 g of powdered milk (2) Contains 40 μg or more and 70 μg or less of aspartic acid per 1 g of powdered milk. (3) Contains tyrosine in an amount of 16 μg or more and 90 μg or less per gram of powdered milk. (4) Contains glutamic acid, aspartic acid, and tyrosine, with the total amount of these three ingredients being 456 μg or more and 880 μg or less per 1 g of powdered milk. A step of adding a lactic acid bacteria starter to the fermentation mix to which the whey powder has been added and fermenting it; A method for producing fermented milk comprising:

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