Non-fermented high-protein milk beverage and method for producing same

Abstract

To provide a non-fermented high-protein milk beverage which contains protein at a high concentration yet has low viscosity, favorable flavor, and good drinkability, and a method for producing the same.SOLUTION: A method for producing a non-fermented high-protein milk beverage having a protein content of 5 mass% or more, the method comprising a step of mixing raw milk with an endo-type neutral protease, and a step of treating the obtained mixture at 15-80°C for 30-90 minutes within a neutral pH range, the beverage containing an endo-type neutral protease degradation product of the raw milk.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a non-fermented high-protein milk beverage and a method for producing the same. [Background technology]

[0002] In response to growing health consciousness among consumers, various high-protein dairy products, such as high-protein fermented milk, have been developed. Theoretically, adding protease to high-protein dairy products breaks down the proteins, which can reduce viscosity. However, adding protein to increase the protein content of dairy products often results in clumping and increased viscosity, making it difficult to obtain a milk beverage that is easy to drink.

[0003] On the other hand, Patent Document 1 describes a method for producing fermented milk by preparing a mixture of raw milk ingredients, adding a lactic acid bacteria starter and a protease, and then fermenting the mixture. However, the product obtained by this method is fermented milk and yogurt with a sufficient hardness, and is not a milk drink. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-41686 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a non-fermented, high-protein milk beverage that contains a high concentration of protein but has a low viscosity, a good taste, and is easy to drink, and a method for producing the same. [Means for solving the problem]

[0006] The inventors have therefore discovered that by adding a certain amount of endo-type neutral protease to raw milk and treating it for a short period of time in the neutral range, it is possible to obtain a non-fermented, high-protein milk beverage that has a protein content of 5% by mass or more, low viscosity, good taste, and is easy to drink, even though the treatment conditions are such that fermentation does not occur, and have completed the present invention.

[0007] That is, the present invention provides the following [1] to [9]. [1] A non-fermented high-protein milk beverage containing an endo-type neutral protease hydrolysate of raw milk and having a protein content of 5% by mass or more. [2] The non-fermented high-protein milk beverage according to [1], wherein the endo-type neutral protease is an endo-type neutral protease that decomposes κ-casein in the neutral range. [3] A non-fermented high-protein milk beverage according to [1] or [2], wherein the endo-type neutral protease is derived from a bacterium belonging to the genus Penibacillus. [4] A non-fermented high-protein milk beverage according to any one of [1] to [3], having a protein content of 5% by mass or more and 15% by mass or less. [5] A step of mixing an endo-type neutral protease with raw milk; and A step of treating the mixture in a neutral range at 15 to 80°C for 30 to 90 minutes A method for producing a non-fermented high-protein milk beverage having a protein content of 5% by mass or more, which contains an endo-type neutral protease hydrolysate of raw milk. [6] The production method according to [5], wherein the amount of the endo-type neutral protease added is 0.5 to 9.5 PU / g casein based on the mass of casein in the raw milk. [7] The production method according to [5] or [6], wherein the endo-type neutral protease is an endo-type neutral protease that decomposes κ-casein in the neutral range. [8] The method according to any one of [5] to [7], wherein the endo-type neutral protease is derived from a bacterium belonging to the genus Penibacillus. [9] The method according to any one of [5] to [8], wherein the protein content in the non-fermented high-protein milk beverage is 5% by mass or more and 15% by mass or less. [Effects of the Invention]

[0008] According to the present invention, even though the processing conditions are such that fermentation does not occur, a non-fermented high-protein milk beverage is obtained that has a protein content of 5% by mass or more, has low viscosity, a good taste, and is easy to drink. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a graph showing the change in viscosity of a reaction solution obtained by reacting 30% skim milk with an endo-type neutral protease. [Figure 2] FIG. 1 shows the change in viscosity of a reaction solution obtained by reacting 10% micellar casein protein with an endo-type neutral protease. [Figure 3] FIG. 1 is a graph showing the change in viscosity of a reaction solution obtained by reacting 10% milk protein with an endo-type neutral protease. DETAILED DESCRIPTION OF THE INVENTION

[0010] Terms used in this specification are used in the sense commonly used in the art unless otherwise specified.

[0011] In this specification, a non-fermented milk beverage is a milk beverage that is not fermented by lactic acid bacteria. A milk beverage is a milk beverage in which ingredients other than dairy products are added to raw milk. The raw milk may contain casein, and a common milk-derived raw material may be used. Examples of such raw milk include raw milk, cow's milk, special cow's milk, raw goat's milk, pasteurized goat's milk, raw sheep's milk, adjusted milk, low-fat milk, non-fat milk, processed milk, cream, butter, butter oil, cheese, concentrated whey, ice cream, concentrated milk, concentrated skim milk, unsweetened evaporated milk, unsweetened evaporated skim milk, sweetened evaporated milk, sweetened evaporated skim milk, whole milk powder, skim milk powder, cream powder, casein powder, milk protein powder, whey powder, protein-enriched whey powder, buttermilk powder, and other liquid and powder solutions. The ingredients other than dairy products are not particularly limited, but examples thereof include nutrients (calcium, vitamins, mineral sugars), sweeteners (monosaccharides, oligosaccharides, sugar alcohols, synthetic sweeteners, etc.), stabilizers (gelatin, pectin, carrageenan, xanthan gum, etc.), coffee, fruit juice, fruit pulp, flavorings, vegetable proteins (soybean-derived, wheat-derived, pea-derived, etc.), enzymes (lactose-degrading enzymes, protease, etc.), etc. Furthermore, the non-fermented high-protein milk beverage refers to the non-fermented milk beverage described above, which has a protein content of 5% by mass or more. In this specification, the protein may contain casein, and may further contain proteins other than casein. The proteins other than casein are not particularly limited, but include, for example, whey protein, vegetable protein, etc. Vegetable protein sources include soybeans, peas, chickpeas, fava beans, almonds, walnuts, pistachios, hazelnuts, cashew nuts, pecan nuts, macadamia nuts, rice, oats, wheat, etc. The protein content can be measured by the Kjeldahl method or the combustion method. The specific procedures are published in the "Food Labeling Standards (March 30, 2015, Food Labeling Table No. 139) Annex: Analytical Methods for Nutritional Components, etc."

[0012] One aspect of the present invention is a method for producing a non-fermented high-protein milk beverage having a protein content of 5% by mass or more and containing an endo-type neutral protease digest of raw milk, the method comprising the steps of mixing raw milk with an endo-type neutral protease (step 1) and treating the mixture at a neutral pH range of 15 to 80°C for 30 to 90 minutes (step 2).

[0013] The raw material milk used in (Step 1) is not particularly limited, but may be any of the raw material milks described above, and these may be used in combination.

[0014] The milk fat content in the raw milk is preferably 0 to 10% by mass, more preferably 0.1 to 5.0% by mass, and even more preferably 1.0 to 5.0% by mass. The non-fat milk solids contained in the raw milk are preferably 3.0 to 20% by mass, and include proteins mainly composed of casein, sugars mainly composed of lactose, and salts mainly composed of various inorganic salts.

[0015] The endo-type neutral protease used in (Step 1) has the effect of roughly degrading proteins and breaking them down into smaller molecules. The endo-type neutral protease is preferably derived from bacteria belonging to the genus Penibacillus and is capable of degrading κ-casein in the neutral pH range, and more preferably has the following properties: (1) Produced by bacteria belonging to the genus Penibacillus (2) Decomposes κ-casein and hemoglobin in the neutral range. (3) The optimum pH is 7.0 to 8.0. (4) It is a neutral protease that is stable at pH 5.5 to 9.0. (5) It acts at temperatures between 20 and 75°C, with an optimum temperature of 55°C. (6) The molecular weight is estimated to be 32,000 to 34,000 Da by electrophoresis. The genus Penibacillus was previously classified as part of the genus Bacillus, but has recently been reclassified and proposed as a new genus. Proteases with the above properties can be obtained from bacteria belonging to the genus Penibacillus, other species including Penibacillus sp., or Penibacillus polymyxa, which has been re-identified from Bacillus polymyxa. In some literature, it is sometimes referred to as Bacillus polymyxa, but these terms are synonymous.

[0016] As the protease that can be used in the present invention, a protease having the following properties is preferred. (a) Effect It exhibits the general properties of a neutral protease, and decomposes proteins such as casein and hemoglobin in the neutral pH range to produce peptides or free amino acids. It has been confirmed that 12 peptide bonds of the oxidized insulin B chain are cleaved: Pha(1)-Val(2), His(5)-Leu(6), His(10)-Leu(11), Glu(13)-Ala(14), Ala(14)-Ler(15), Ler(15)-Tyr(16), Tyr(16)-Leu(17), Leu(17)-Val(18), Gly(23)-Phe(24), Phe(24)-Phe(25), Phe(25)-Tyr(26), and Lys(29)-Ala(30). (b) Substrate specificity It exhibits mild proteolytic activity against κ-casein in the neutral pH range, but shows almost no proteolytic activity against α-casein and β-casein, even in the neutral pH range. (c) Optimum pH and stable pH range a) Optimal pH: The optimal pH for proteolytic action on κ-casein is 7.0 to 8.0. Stable pH range: Extremely stable in the range of 5.5 to 9.0. (d) Optimum temperature range It works in the temperature range of 20℃ to 75℃, with the optimum temperature being 50℃ to 60℃. The optimum temperature is 55℃. (e) Inactivation conditions such as pH and temperature The activity is completely lost at pH 3.0 or below and pH 10.0 or above, and is completely inactivated by heat treatment at 65°C for 10 minutes. (f) Inhibition, activation and stabilization It is inhibited by metal chelators such as ethylenediaminetetraacetate (EDTA), citric acid, 0-phenanthroline, 2,2-dipyridyl, and sodium fluoride, and by oxidizing agents such as N-bromosuccinimide (NBS) and iodine. It is stabilized by calcium ions and requires zinc ions for activity. (g)Molecular weight The molecular weight by electrophoresis is estimated to be 32,000 to 34,000 Da.

[0017] The amount of the endo-type neutral protease added is preferably 0.5 to 9.5 PU / g casein based on the mass of casein in the raw milk, from the viewpoints of reducing the viscosity of the resulting milk beverage, preventing aggregation, and suppressing deterioration in taste, and the more preferred amount is 0.5 to 9.3 PU / g casein. The amount of protease added (enzyme amount) can be calculated as enzyme activity per mass of enzyme, based on the enzyme amount defined as 1.0 PU, as follows: 1 mL of enzyme dilution was added to a 0.6% casein aqueous solution (pH 7.5, 50 mM Tris-HCl buffer containing 2 mM calcium acetate) and incubated at 30°C for 10 minutes. The reaction was stopped by adding 5 mL of trichloroacetic acid reagent (pH 4.0, 1.8% anhydrous sodium acetate, 1.8% trichloroacetic acid, 1.98% acetic acid). The mixture was then left at 30°C for 30 minutes, filtered, and the absorbance at 275 nm was measured. One PU (Protease Unit) is defined as the amount of enzyme (enzyme activity) that liberates an amino acid equivalent to 1 μg of tyrosine per minute under these conditions.

[0018] Various ingredients can be added as needed in step 1. Specific examples include the above-mentioned non-dairy ingredients, metal salts that contribute to the stabilization of the milk beverage, various sugars, ascorbic acid, glycerin, etc., excipients for improving usability such as starch, dextrin, inorganic salts with buffering properties, and milk-derived ingredients such as lactose, whey, and milk proteins.

[0019] (Step 2) is a step of treating the mixed solution obtained in step 1 in a neutral range at 15 to 80° C. for 30 to 90 minutes. Here, the neutral range refers to a pH range of 6.0 to 9.0, more preferably 6.5 to 8.0, and even more preferably 7.0 to 8.0. The treatment temperature is preferably 15 to 80°C, more preferably 20 to 70°C, further preferably 25 to 60°C, and particularly preferably 30 to 45°C. The treatment time is preferably 30 to 90 minutes, more preferably 40 to 90 minutes. After the reaction, the enzyme reaction can be stopped by cooling to 15°C or below. Proteases may be active in unfermented high-protein milk beverages or inactivated. Proteases can be inactivated by heat treatment, lowering the pH, etc.

[0020] By carrying out the above steps 1 and 2, it is possible to obtain a non-fermented high-protein milk beverage containing an endo-type neutral protease decomposition product of raw material milk and having a protein content of 5% by mass or more. That is, another aspect of the present invention is a non-fermented high-protein milk beverage containing an endo-neutral protease digest of raw material milk and having a protein content of 5% by mass or more. The endo-type neutral protease decomposition product contained in the milk beverage of the present invention is an endo-type neutral protease decomposition product of the raw material milk produced in the above steps 1 and 2. As described above, this decomposition product is a product in which proteins have been roughly decomposed, since the endo-type neutral protease used is an enzyme that has the effect of roughly decomposing proteins and breaking them down into smaller molecules. The protein content in the milk drink of the present invention is preferably from 5 to 15% by mass, more preferably from 6 to 15% by mass, and even more preferably from 8 to 14% by mass. The casein content in the milk beverage of the present invention is preferably 1% by mass or more and 15% by mass or less, more preferably 3% by mass or more and 15% by mass or less, even more preferably 6% by mass or more and 14% by mass or less, and particularly preferably 8% by mass or more and 14% by mass or less. The milk fat content in the milk drink of the present invention is preferably 0 to 10% by mass, more preferably 0.1 to 5.0% by mass, and even more preferably 1.0 to 5.0% by mass.

[0021] The non-fermented high-protein milk beverage of the present invention has low viscosity, a good taste, and is easy to drink, and is therefore useful as an RTD (Ready-To-Drink) protein beverage, etc. [Example]

[0022] The present invention will now be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0023] Example 1 (Change in viscosity of 30% skim milk) <Method> A 150 g solution of 30% skim milk (10% protein content) was prepared using skim milk (Morinaga Milk Industry) and dispensed into six 50 mL centrifuge tubes (20 g each). The endo-type neutral protease ADMIL (Godo Shusei) derived from Penibacillus sp. was added at 0.01% (6.2 PU / g casein), 0.015% (9.3 PU / g casein), or 0.02% (12.3 PU / g casein) and the mixture was allowed to react at 40°C for 1 hour. 6.7 mL of the reaction mixture was dispensed into a dedicated chamber (SC4-13R) and cooled at 10°C for 1 hour before viscosity measurement (VISCOMETER DV-I Prime, Brookfield, using an SC4-18 spindle). <Result> The viscosity of samples reacted with 30% skim milk and ADMIL is shown in Figure 1. A significant decrease in viscosity was observed in samples containing 0.01% ADMIL (6.2 PU / g casein). The viscosity decreased further with the addition of 0.015% (9.3 PU / g casein), but the viscosity tended to increase with the addition of 0.02% (12.3 PU / g casein) compared to the 0.01% and 0.015% additions. In the range where the ADMIL reaction is small, it is thought that fluidity increases as proteins are broken down in a fairly regular manner. On the other hand, in the range where the reaction is large, proteins are broken down randomly, and the mixing of proteins with various charges creates an attractive force, which is thought to cause protein aggregation. High-protein milk has a higher viscosity than cow's milk, and therefore issues arise in terms of production, such as protein solubility, and in terms of flavor, such as roughness and a poor mouthfeel. Using an appropriate concentration of ADMIL can achieve a low viscosity effect that solves these problems.

[0024] Example 2 (Change in viscosity of 10% protein-containing casein micelle protein solution) <Method> 40.2 g of micellar casein protein (Nichie) was dissolved in 290 g of sterile water and dispensed into six 50 mL centrifuge tubes (50 g each). After incubation at 40°C for 10 minutes, ADMIL (United Spirits) was added at concentrations of 0.001% (0.5 PU / g casein), 0.005% (2.5 PU / g casein), 0.01% (5.0 PU / g casein), and 0.02% (10.0 PU / g casein) and allowed to react for 1 hour. After cooling to 10°C for 1 hour, 13.5 mL of the reaction mixture was dispensed into a dedicated chamber (SC4-13R) and viscosity was measured (VISCOMETER DV-I Prime, BROOK FIELD, using an SC4-29 spindle). <Result> ADMIL was added to a casein micelle protein solution, and the difference in viscosity was measured. The results are shown in Figure 2. A concentration-dependent decrease in viscosity was observed when ADMIL was added from 0.001 to 0.01% (0.5 to 5.0 PU / g casein), but when 0.02% (10.0 PU / g casein) was added, curdling and protein separation were observed.

[0025] Example 3 (Change in viscosity of 10% protein-containing milk protein solution and sensory evaluation) <Method> 38.0 g of milk protein MPC (Nichie) was dissolved in 262 g of sterile water and dispensed into six 50 mL centrifuge tubes (40 g each). After incubation at 40°C for 10 min, ADMIL (United Spirits) was added at 0.001% (0.8 PU / g casein), 0.005% (3.8 PU / g casein), 0.01% (7.6 PU / g casein), or 0.015% (11.4 PU / g casein) and allowed to react for 1 hour. After cooling to 10°C for 1 hour, 13.5 mL of the reaction mixture was dispensed into a dedicated chamber (SC4-13R) and viscosity was measured (Viscometer DV-I Prime, Brookfield, SC4-29 spindle). Sensory evaluation was performed on the ADMIL-free and 0.005% ADMIL samples. Two types of tests using the three-point discrimination method were conducted on 15 panelists, and significance tests were conducted on a total of 30 test answers. <Result> ADMIL was added to a milk protein solution, and the difference in viscosity was measured. The results are shown in Figure 3. When 0.001 to 0.01% ADMIL (0.8 to 7.6 PU / g casein) was added, the viscosity tended to decrease depending on the addition concentration, but at 0.015% (11.4 PU / g casein), the viscosity increased. For the sample containing 0.005% ADMIL (3.8 PU / g casein), the significance of the difference in viscosity from the control sample was examined in a sensory evaluation test using the three-point discrimination method. Since there were 19 correct answers out of 30 panelists, which was below the significance level of 0.1%, it was determined that there was a significant difference.

Claims

1. A non-fermented high-protein milk beverage containing an endo-type neutral protease hydrolysate of raw milk and having a protein content of 5% by mass or more.

2. 2. The non-fermented high-protein milk beverage according to claim 1, wherein the endo-type neutral protease is an endo-type neutral protease that degrades κ-casein in the neutral range.

3. 2. The non-fermented high-protein milk beverage according to claim 1, wherein the endo-type neutral protease is derived from a bacterium belonging to the genus Penibacillus.

4. 2. The non-fermented high-protein milk beverage according to claim 1, having a protein content of 5% by mass or more and 15% by mass or less.

5. A step of mixing an endo-type neutral protease with raw milk; a step of treating the mixture at a neutral temperature of 15 to 80°C for 30 to 90 minutes; A method for producing a non-fermented high-protein milk beverage having a protein content of 5% by mass or more, which contains an endo-type neutral protease hydrolysate of raw milk,

6. 6. The method according to claim 5, wherein the amount of the endo-type neutral protease added is 0.5 to 9.5 PU / g casein based on the mass of casein in the raw milk.

7. 6. The method according to claim 5, wherein the endo-type neutral protease is an endo-type neutral protease that degrades κ-casein in the neutral range.

8. The method according to claim 5, wherein the endo-type neutral protease is derived from a bacterium belonging to the genus Penibacillus.

9. The method according to claim 5, wherein the protein content in the non-fermented high-protein milk beverage is 5% by mass or more and 15% by mass or less.

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