Method for producing milk powders

Abstract

To provide a method for producing versatile milk powders that do not need a special production process, have a natural flavor, and have fewer limitations of application for food raw material.SOLUTION: Provided is a method for producing milk powders including: a step of preparing liquid raw material milk; a step of adjusting pH of the liquid raw material milk to 6.70 or more and 9.00 or less; and a step of drying the pH-adjusted liquid raw material milk.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing powdered milk, and more particularly to a method for producing 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] As techniques for improving the off-flavor of powdered milk, for example, the following documents are known. 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, the present invention aims to provide a method for producing versatile milk powders that not only does not require special production processes, but also 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 pH of raw milk to a specific range, or by adjusting the pH of water used when dissolving powdered raw milk in water to a specific range, it is possible to produce powdered milk products that have a strong sweet taste, a milky flavor, and improved off-flavors such as oxidized odor, grass odor, and astringency, and have thus completed the present invention. That is, the present invention has the following configuration. <1> A method for producing milk powder, comprising: Preparing liquid raw milk; adjusting the pH of the liquid raw milk to 6.70 or more and 9.00 or less; a step of drying the pH-adjusted liquid raw material milk; The method for producing said milk powder comprises: <2> The liquid raw milk is whey, and the milk powder is whey powder. <1> The manufacturing method described in <3> The pH is 6.70 or more and 7.65 or less. <1> or <2> The manufacturing method described in <4> A method for improving the flavor of powdered milk, comprising: Preparing liquid raw milk; adjusting the pH of the liquid raw milk to 6.70 or more and 9.00 or less; a step of drying the pH-adjusted liquid raw material milk; A method for improving the flavor of powdered milk comprising: <5> The liquid raw milk is whey, and the powdered milk is whey powder. <4> The flavor improving method described in . <6> The pH is 6.70 or more and 7.65 or less. <4> or <5> The flavor improving method described in . [Effects of the Invention]

[0007] According to the present invention, by the simple process of adjusting the pH of liquid raw milk to between 6.70 and 9.00 and then drying it, it is possible to produce powdered milk that has a strong sweetness, a milky flavor, and suppressed oxidized odor, grass odor, and astringency. Therefore, there is no need to add special production equipment compared to conventional production of powdered milk. Furthermore, since the powdered milk obtained by the production method of the present invention does not require the addition of other food ingredients, it can be added to a variety of foods without being limited to the food to be used. DETAILED DESCRIPTION OF THE INVENTION

[0008] (Milk powder) The milk powders produced by the production method 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 skim 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] The milk powders produced by the production method of the present invention have the same components as general 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 produced by the production method of the present invention has the same components as general whey powder, with protein 5.0% to 20.0%, lipid 0.01% to 8.0%, carbohydrates 60.0% to 80.0%, and ash 0.01% to 10.0%. The lipid content of milk powder produced by the production method of the present invention is preferably 0.5% to 6.0%, more preferably 1.0% to 4.0%, and the lipid content of whey powder produced by the production method 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 produced by the production method of the present invention is preferably 6.0% to 9.0%, more preferably 6.5% to 8.0%.The ash content of the whey powder produced by the production method 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 milk powder of the present invention is characterized by including a step of adjusting the pH of liquid raw milk to between 6.70 and 9.00, and the timing of pH adjustment is not important. Therefore, it can be done at any time up to the time when the liquid raw milk is dried to obtain powdered milk powder. Below, the production method of the present invention will be explained using an example in which the raw milk is whey. Steps for producing whey powder from liquid whey as a raw material include a step of preparing liquid whey, a step of sterilizing liquid whey, a step of concentrating liquid whey, and a step of drying liquid whey. Here, the pH of liquid whey can be adjusted before or after the sterilization step, before or after the concentration step, or before or after the drying step. That is, the whey may be prepared in the following order: pH adjustment, sterilization, concentration, and drying; liquid whey may be prepared in the following order: sterilization, pH adjustment, concentration, and drying; or whey may be prepared in the following order: sterilization, concentration, pH adjustment, and drying. Alternatively, whey may be prepared in the following order: sterilization, concentration, pH adjustment, and drying. Alternatively, whey powder may be dried into a powder and dissolved in a liquid such as water to prepare liquid whey, followed by pH adjustment. 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 pH may be adjusted and the liquid whey may be dried to improve the flavor of the original whey powder. When cheese whey is used, the preferred order is cheese whey preparation, pH adjustment, sterilization, concentration, and drying. According to the present invention, it has been confirmed that when whey powder whose flavor has been improved by pH adjustment is used in food production, the flavor of the whey powder can be maintained regardless of the pH of the food ingredients added (see Production Example 2 described below). In this respect, the method for producing whey powder of the present invention can also be said to be a method for improving the quality of whey powder.

[0012] In the present invention, the drying step is not limited as long as it can dry the pH-adjusted liquid raw milk into a powder. Among these, the so-called spray drying step, in which the 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 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.

[0013] The pH adjustment step of the present invention is a step of adjusting the pH of raw milk to 6.70 or more and 9.00 or less. The pH may be adjusted appropriately within this range depending on the preference of the target food or drink, and is preferably 6.70 or more and 7.65 or less. In the present invention, the pH can be adjusted, for example, by adding a pH adjuster. The pH adjuster may be any pH adjuster commonly used in foods, such as trisodium citrate, sodium bicarbonate, sodium hydroxide, or citric acid.

[0014] According to the production method of the present invention, the flavor of the resulting milk powder can be improved by adjusting the pH. Therefore, the production method 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, reduced oxidized odor, reduced grass odor, and reduced astringency. It is preferable to adjust the pH so that the flavor is improved in at least one of the evaluation criteria, more preferably in two or more flavor categories, even more preferably in three or more flavor categories, and most preferably in all categories. Whether or not flavor has been improved can be determined by comparing the sensory evaluation of a specialist panel between drinking or consuming a milk powder with an unadjusted pH and drinking or consuming a milk powder with a pH adjusted to the range of the present invention. The milk powders with improved flavor according to the present invention can be used in the production of a variety of foods and beverages. 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. The expanded use of cheese whey, which has a distinctive cheese-derived odor, is particularly significant. Examples of foods and beverages include beverages, fermented foods such as yogurt, confectionery, 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] [Example 1] The relationship between pH-adjusted liquid whey and flavor was investigated. 1. How to adjust whey pH Whey powder produced overseas was dissolved in water to a concentration of 10%, and the pH of the liquid whey was adjusted. A benchtop pH meter LAQUA F-73 (manufactured by HORIBA) was used as the pH measuring device. The pH was adjusted using sodium hydroxide or lactic acid. The component values ​​of each whey powder and the pH when dissolved in water are as follows. In this specification, % indicates % by mass unless otherwise specified. <Desalted whey powder> Protein 12.3% Fat 1.0% Carbohydrates 78.7% Ash content 6.0% pH 6.40 <Sweet whey powder> Protein 11.0% Fat 1.5% Carbohydrates 72.0% Ash content 7.4% pH 6.36

[0016] 2. Sensory evaluation test method Approximately 20 mL of each liquid whey obtained after pH adjustment was dispensed into plastic cups, and six trained expert panelists drank and evaluated the flavor. The flavor evaluation criteria were "sweetness," "milky flavor," "oxidized odor," "grass odor," and "astringency." Scoring was based on a score of 0 for an unadjusted pH (a product obtained by simply dissolving desalted whey powder in water to a concentration of 10%), and relative evaluation was conducted in 0.5-point increments from -3 to +3, with the average score calculated from the six panelists. Higher scores for "sweetness" and "milky flavor" were considered desirable, while lower scores for "oxidized odor," "grass odor," and "astringency" were considered desirable.

[0017] <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 "Grassy" The scent of green grass or dry grass "Astringency" - Astringency of the taste

[0018] <Grade definition> -3 Very weak -2 Slightly weak -1 slightly weaker 0 Neither +1 slightly stronger +2 Slightly strong +3 Very strong

[0019] [Table 1]

[0020] [Table 2]

[0021] 3.Results The sensory evaluation results of the pH-adjusted desalted whey powder are shown in Table 1, and the evaluation results of the pH-adjusted sweet whey powder are shown in Table 2. Adjusting the pH of liquid whey from 6.55 to 9.00 resulted in an improvement in flavor in some categories. In particular, at a pH of 6.70 or higher, sweetness and milk flavor increased, while off-flavors such as oxidized odor, grass odor, and astringency were suppressed, resulting in an improvement in flavor in all categories compared to when the pH was not adjusted. Considering ease of use as a food ingredient, it is preferable to adjust the pH of liquid whey to between 6.70 and 7.65.

[0022] [Example 2] Whey powder was produced by the production method of the present invention using whey obtained during the production of natural cheese as raw milk, and was evaluated. 1. Whey powder manufacturing method Liquid whey (pH 6.20) obtained in natural cheese production was adjusted to pH 7.20 by adding 12% NaOH solution. The pH-adjusted whey was sterilized at 130°C for 4 seconds in a plate heat exchanger (DK-8600, manufactured by APV). The sterilized whey was cooled to approximately 30°C in the same plate heat exchanger. The cooled whey was concentrated under reduced pressure in a rotary evaporator (RE-10ED-120, manufactured by Shibata Chemical Instruments Co., Ltd.) until the solid content reached 45%. The temperature during concentration was 30°C. The concentrated whey was spray-dried to obtain whey powder with a lipid content of 4.0%, a protein content of 11%, an ash content of 8.2%, and a pH of 7.20. As a control, whey powder without pH adjustment was also prepared. Each of the obtained whey powders was dissolved in water to a concentration of 10%, and a sensory evaluation was carried out in the same manner as in Example 1.

[0023] [Table 3]

[0024] 2.Results The evaluation results are shown in Table 3. It was confirmed that by adjusting the pH of the liquid whey obtained in cheese production to 7.20, the evaluation was higher in all items than when the pH was not adjusted.

[0025] [Example 3] The pH of liquid whey obtained by adding fat to defatted liquid whey was adjusted. 1. Manufacturing method Liquid whey (pH 6.20) obtained during natural cheese production was defatted and then concentrated three-fold through a nanofiltration process. Defatted fat was added to the mixture so that the lipid content per solid was 3.0%, and a 12% NaOH solution was added to adjust the pH of the whey to 7.20. Pasteurization, concentration, and drying were performed under the same conditions as in Example 2, yielding whey powder with a lipid content of 3.0%, protein content of 11%, ash content of 7.5%, and a pH of 7.20. As a control, whey powder without pH adjustment was also prepared. Each of the obtained whey powders was dissolved in water to a concentration of 10%, and a sensory evaluation was carried out in the same manner as in Example 1.

[0026] [Table 4]

[0027] 2.Results The evaluation results are shown in Table 4. It was confirmed that when the liquid whey obtained in cheese production was defatted and the fat was returned to the whey, adjusting the pH to 7.20 resulted in higher evaluations in all categories compared to when the pH was not adjusted.

[0028] [Production Example 1] Production of coffee milk drink 1. Manufacturing method of coffee milk drink Desalted whey powder was dissolved in water to a concentration of 10%, and NaOH solution was added to adjust the pH of the whey to 7.00. Pasteurization, concentration, and drying were performed under the same conditions as in Example 2 to obtain whey powder with a pH of 7.00. The obtained whey powder was added to a coffee milk beverage at a concentration of 1.4%. As a control, the same desalted whey powder without pH adjustment was added to a coffee milk beverage.

[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 0.5 points and the sweetness was 0.8 points. Therefore, it was found that the milk flavor and sweetness of dairy drinks can be improved by using the whey powder of the present invention having a pH of 7.00.

[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 7.00 obtained in Production Example 1 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 desalted whey powder without pH 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 0.5 points, the sweetness was 0.3 points, and the astringency was -0.7 points. Therefore, it was found that by using the whey powder of the present invention with a pH of 7.00, the milk flavor and sweetness of yogurt can be increased and the astringency can be suppressed.

[0034] As can be seen from the above examples and production examples, by using powdered milk adjusted to a pH of 6.55 to 9.00 in food and beverages, it is possible to increase the sweetness and milk flavor and suppress off-flavors such as oxidized odors, grass odors, and astringency compared to conventional powdered milks.

Claims

1. A method for producing milk powder, comprising: Preparing liquid raw milk; adjusting the pH of the liquid raw material milk to 6.70 or more and 9.00 or less; a step of drying the pH-adjusted liquid raw material milk; The method for producing said milk powder comprises:

2. 2. The method according to claim 1, wherein the liquid raw milk is whey and the powdered milk is whey powder.

3. The method according to claim 1 or 2, wherein the pH is 6.70 or more and 7.65 or less.

4. A method for improving the flavor of powdered milk, comprising: Preparing liquid raw milk; A step of adjusting the pH of the liquid raw material milk to 6.70 or more and 9.00 or less; a step of drying the pH-adjusted liquid raw material milk; A method for improving the flavor of powdered milk comprising:

5. 5. The flavor improving method according to claim 4, wherein the liquid raw milk is whey and the powdered milk is whey powder.

6. 6. The flavor improving method according to claim 4 or 5, wherein the pH is 6.70 or more and 7.65 or less.

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