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 the δ lactone concentration of the liquid raw material milk; and a step of drying the 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] 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 present inventors have discovered that by adjusting the δ lactone concentration of raw milk to produce powdered milk, it is possible to produce powdered milk that is strongly sweet, has a milky flavor, and is improved in 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; A step of adjusting the δ lactone concentration of liquid raw material milk; a step of drying the adjusted liquid raw material milk; A method for producing powdered milk comprising the steps of: <2> The milk powder is whey powder. <1> The manufacturing method described in <3> The step of adjusting the δ lactone concentration is a step of adding δ lactone or milk fat, <1> or <2> A method for producing powdered milk according to the above item (1). <4> The step of adjusting the δ lactone concentration is a step of adjusting the δ lactone concentration in powdered milk to 400 ppb or more and less than 400 ppm. <1> or <2> A method for producing powdered milk according to the above item (1). <5> The method further includes a step of adjusting the pH of the liquid raw milk to 6.55 or more and 9.0 or less. <1> or <2> A method for producing powdered milk according to the above item (1). <6> A method for improving the flavor of powdered milk, comprising: Preparing liquid raw milk; A step of adjusting the δ lactone concentration of liquid raw material milk; a step of drying the adjusted liquid raw material milk; A method for improving the flavor of powdered milk comprising: <7> The milk powder is whey powder. <6> The flavor improving method described in . <8> The step of adjusting the δ lactone concentration is a step of adding δ lactone or milk fat, <6> or <7> The flavor improving method described in . <9> The step of adjusting the δ lactone concentration is a step of adjusting the δ lactone concentration in powdered milk to 400 ppb or more and less than 400 ppm. <6> or <7> The flavor improving method described in . <10> The method further includes a step of adjusting the pH of the liquid raw milk to 6.55 or more and 9.0 or less. <6> or <7> The flavor improving method described in . <11> The improvement in flavor is improvement in oxidized odor, grass odor, or astringency. <6> The flavor improving method described in . [Effects of the Invention]

[0007] According to the present invention, by the simple process of adjusting the δ-lactone concentration of liquid raw milk to a specific range and then drying it, it is possible to produce milk powders that have a strong sweetness, a milky flavor, and suppressed oxidized odor, grass odor, and astringency. Therefore, there is no need to add special production equipment to the conventional production of milk powders. Furthermore, since the milk powders obtained by the production method of the present invention do not contain any additional food components that are not originally contained in the raw milk, they can be added to a variety of foods and used in a wide range of foods. 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 are produced by adjusting the delta lactone concentration of the liquid raw milk. The delta lactone content of the milk powders is preferably 400 ppb or more. A preferred range is 400 ppb or more but less than 400 ppm, more preferably 400 ppb or more but less than 100 ppm, and even more preferably 500 ppb or more but less than 10 ppm. The concentration of each δ lactone can be measured by gas chromatography or the like. 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 5.0%, 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 comprising a step of adjusting the δ-lactone concentration of liquid raw milk. The δ-lactone concentration refers to the total concentration of δ-octalactone, δ-decalactone, δ-undecalactone, and δ-dodecalactone. The delta lactone concentration can be adjusted by externally adding one or more of the above delta lactones to liquid raw milk. The delta lactone concentration can also be adjusted by adjusting the fat percentage of the raw milk. For example, the delta lactone concentration can be adjusted by adding fat to skim milk obtained by skimming raw milk. In this case, the fat added may be the fat obtained in the skimming process, or it may be fat obtained from a source other than the raw milk. The step of adjusting the δ lactone concentration may be carried out at any time up to the time when the liquid raw milk is dried to obtain a powdered milk powder. The following describes a production method using whey as the raw milk. The steps for producing whey powder from liquid whey as the raw material include preparing liquid whey, sterilizing the liquid whey, concentrating the liquid whey, and drying the liquid whey. The timing for adjusting the δ lactone 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, a δ lactone concentration adjustment step, a sterilization step, a concentration step, and a drying step; after the liquid whey preparation step, a sterilization step, a δ lactone concentration adjustment step, a concentration step, and a drying step; or after the whey preparation step, a sterilization step, a concentration step, a δ lactone concentration adjustment step, and a drying step. Alternatively, the dried whey powder may be dissolved in a liquid such as water to prepare liquid whey, and then the δ lactone 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 δ lactone concentration may be adjusted and dried to improve the flavor of the original whey powder. When cheese whey is used, the production order is preferably the following order: after the cheese whey preparation step, a δ lactone concentration adjustment step, a sterilization step, a concentration step, and a drying step. In the present invention, the δ lactone concentration in liquid whey during the production process may be adjusted so that the δ lactone concentration when dried to whey powder falls within the above-mentioned preferred concentration range. According to the present invention, it has been confirmed that when whey powder whose flavor has been improved by adjusting the delta lactone concentration is used in food production, the flavor of the whey powder can be maintained regardless of the delta lactone concentration or pH of the food ingredients added (see Production Example 2 described below). Therefore, in this respect, the method for producing whey powder of the present invention can also be said to be a method for improving whey powder. In the present invention, synthetic or isolated δ lactone can be added to whey, a raw material containing δ lactone can be added to whey, or both can be used. The above-mentioned synthetic or isolated δ lactone can be synthesized or isolated by oneself or purchased commercially. When synthetic or isolated δ lactone is added to whey, the synthetic or isolated δ lactone can be added alone, or, as described below, it can be added to whey together with other additives, such as excipients and binders. Alternatively, the synthetic or isolated δ lactone can be added to whey in the form of a flavor composition containing other components. The separation can be performed using conventional methods used to separate components derived from animal or plant tissues, including, but not limited to, steam distillation, solvent extraction, compression (direct, high-temperature, or low-temperature), and supercritical fluid extraction. Synthetic or isolated δ lactone can also be used in the form of a mixture of the compound with other compounds. For example, chemically synthesized δ lactones can be used without purification to increase their purity.

[0012] In addition, in the method for producing milk powder of the present invention, in addition to adjusting the δ-lactone concentration of the liquid raw milk, it is also preferable to adjust the pH. In this case, the pH is preferably 6.55 to 9.0, more preferably 6.7 to 9.0, and the timing of pH adjustment is not important. Therefore, it can be adjusted at any time from the time when the liquid raw milk is dried to the time when the powdered milk is produced. The pH of the raw milk can be adjusted appropriately within the range depending on the preference of the target food or beverage, and is preferably 6.7 to 7.65. 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.

[0013] In the present invention, the drying step is not limited as long as it can dry liquid raw milk, the δ-lactone concentration of which or the δ-lactone concentration and pH of which have been adjusted, to a powder. Among these, a so-called spray drying step, in which liquid raw milk is sprayed in a heated atmosphere and dried to 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 equipment 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 production method of the present invention, the flavor of the resulting milk powder can be improved by adjusting the δ-lactone concentration of the liquid raw milk. 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. The pH is preferably adjusted so that the above flavors are improved in at least one evaluation category, 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 expert panelists between drinking or consuming milk powder with an unadjusted δ-lactone concentration and drinking or consuming milk powder with a lactone concentration adjusted to the specific 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 the flavor and liquid whey with adjusted delta lactone concentration was investigated. 1. Method for adjusting whey delta lactone concentration Whey powder from overseas was dissolved in water to a concentration of 10%, and each δ-lactone solution was added to adjust the concentration. The lactone solutions used were 98% δ-octalactone, δ-decalactone, δ-undecalactone, and δ-dodecalactone solutions diluted with ethanol to 0.25% (1% as δ-lactone). The component values ​​of each whey powder and the pH when dissolved in water are as follows. % indicates mass % unless otherwise specified. The δ-lactone concentration indicates the total concentration of δ-octalactone, δ-decalactone, δ-undecalactone, and δ-dodecalactone, and each δ-lactone was measured by gas chromatography. In this specification, % indicates mass % unless otherwise specified.

[0016] <Desalted whey powder composition> Protein 12.3% Fat 1.0% Carbohydrates 78.7% Ash content 6.0% δ lactone 80 ppb pH 6.40

[0017] <Sweet whey powder composition> Protein 11.0% Fat 1.5% Carbohydrates 72.0% Ash content 7.4% δ lactone 350 ppb pH 6.40

[0018] 2. Sensory evaluation test method Approximately 20 mL of each liquid whey obtained by adjusting the delta lactone concentration was dispensed into plastic cups, and six trained expert panelists drank and evaluated the flavor. The flavor evaluation items were "sweetness," "milky flavor," "oxidized odor," "grass odor," and "astringency." Scores were calculated relative to the unadjusted delta lactone concentration (a product obtained by simply dissolving desalted whey powder in water to a concentration of 10%), with a score of 0.0000, ranging from -3 to +3 in increments of 0.5 points. The average scores of the six panelists were calculated. Higher scores for "sweetness" and "milky flavor" were considered desirable, while lower scores for "oxidized odor," "grass odor," and "astringency" were considered desirable.

[0019] <Evaluation items> "Sweetness" Sweetness of taste "Milk flavor": Milky and creamy 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

[0020] <Grade definition> -3 Very weak -2 Slightly weak -1 slightly weaker 0 Neither +1 slightly stronger +2 Slightly strong +3 Very strong

[0021] [Table 1]

[0022] [Table 2]

[0023] 3.Results The sensory evaluation results of the desalted whey powder with adjusted delta lactone concentrations are shown in Table 1, and the evaluation results of the sweet whey powder are shown in Table 2. In both cases, the addition of delta lactone improved the flavor in some categories. In particular, when the delta lactone concentration of whey powder was adjusted to 500 ppb or more, it was possible to increase the sweetness or milk flavor and suppress off-flavors such as oxidized odors, grass odors, and astringency, resulting in higher ratings in several categories compared to when the delta lactone concentration was not adjusted. Considering ease of use as a food ingredient, it is preferable to adjust the delta lactone concentration of whey powder to 400 ppb or more.

[0024] [Example 2] Combination of pH adjustment step and δ lactone concentration adjustment step 1. Manufacturing method The same procedure as in Example 1 was carried out except that the pH was set within the range shown in the table below.

[0025] [Table 3]

[0026] [Table 4]

[0027] 2.Results The sensory evaluation results of the desalted whey powder with adjusted delta lactone concentration and pH are shown in Table 3, and the evaluation results of the sweet whey powder are shown in Table 4. Blank cells indicate that no test was performed. These results show that adding delta lactone improved flavor in all aspects, even in the pH range of 6.55 to 9.00. In particular, sweetness and milk flavor were further improved by combining delta lactone concentration adjustment with pH adjustment. Considering ease of use as a food ingredient, it is preferable to adjust the whey powder pH to 7.00 to 7.65 and the delta lactone concentration to 400 ppb or higher.

[0028] [Example 3] Whey powder produced by adding fat to defatted liquid whey 1. 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 7.20. After sterilization, concentration, and drying, whey powder with a lipid content of 3.0%, protein content of 11%, ash content of 7.5%, delta lactone content of 1 ppm, and pH of 7.20 was obtained. As a control, whey without lactone concentration adjustment was also prepared, and a whey powder with the same composition and pH of 7.20 was obtained. 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.

[0029] [Table 5]

[0030] 2.Results The evaluation results are shown in Table 5. In this whey powder manufacturing method, the liquid whey obtained in cheese manufacturing is defatted, and then the defatted fat is returned and dried to adjust the delta lactone concentration to the above-mentioned concentration. In this way, it was confirmed that when the delta lactone concentration was adjusted using fat, the evaluation was higher in all items compared to when the delta lactone concentration was not adjusted.

[0031] [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 delta lactone was added. The solution was sterilized, concentrated, and dried to obtain whey powder with a delta lactone concentration of 1 ppm. The resulting whey powder was added to a coffee milk beverage at 1.4%. As a control, desalted whey powder with an unadjusted delta lactone concentration was added to the coffee milk beverage at 1.4%.

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

[0033] 3.Results The milk flavor was scored at 1.3 points, and the sweetness was scored at 1.6 points. Therefore, it was found that the milk flavor and sweetness of dairy beverages can be improved by using whey powder of the present invention in which the δ lactone concentration has been adjusted to a specific range.

[0034] [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 with an adjusted delta lactone concentration.

[0035] 2. Evaluation Method The "milk flavor," "sweetness," and "astringency" were evaluated according to the methods of Example 1.

[0036] 3.Results The milk flavor was 0.8 points, the sweetness was 1.2 points, and the astringency was -0.7 points. Therefore, it was found that by using whey powder of the present invention in which the δ lactone concentration is adjusted to a specific range, the milk flavor and sweetness of yogurt can be increased and the astringency can be suppressed.

[0037] From the above examples and production examples, by using powdered milk in which the δ lactone concentration is adjusted to a specific range in foods and beverages, it is possible to increase 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; A step of adjusting the δ lactone concentration of liquid raw material milk; a step of drying the adjusted liquid raw material milk; The method for producing said milk powder comprises:

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

3. The method for producing milk powder according to claim 1 or 2, wherein the step of adjusting the δ lactone concentration is a step of adding δ lactone or milk fat.

4. 3. The method for producing powdered milk according to claim 1 or 2, wherein the step of adjusting the delta lactone concentration is a step of adjusting the delta lactone concentration in powdered milk to 400 ppb or more and less than 400 ppm.

5. 3. The method for producing milk powder according to claim 1, further comprising the step of adjusting the pH of the liquid raw milk to 6.55 or more and 9.0 or less.

6. A method for improving the flavor of powdered milk, comprising: Preparing liquid raw milk; A step of adjusting the δ lactone concentration of liquid raw material milk; a step of drying the adjusted liquid raw material milk; A method for improving the flavor of powdered milk comprising:

7. 7. The method for improving flavor according to claim 6, wherein the milk powder is whey powder.

8. The flavor improving method according to claim 6 or 7, wherein the step of adjusting the δ lactone concentration is a step of adding δ lactone or milk fat.

9. 8. The flavor improving method according to claim 6 or 7, wherein the step of adjusting the delta lactone concentration is a step of adjusting the delta lactone concentration in powdered milk to 400 ppb or more and less than 400 ppm.

10. The flavor improving method according to claim 6 or 7, further comprising a step of adjusting the pH of the liquid raw milk to 6.55 or more and 9.0 or less.

11. 7. The method for improving flavor according to claim 6, wherein the improvement of flavor is improvement of oxidized odor, grass odor or astringency.

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