Preparation method of hydrolyzed whey protein

Abstract

The invention belongs to the field of food, and particularly relates to a preparation method of hydrolyzed whey protein. The preparation method of the hydrolyzed whey protein provided by the invention comprises the following steps: performing high-pressure homogenization on a whey protein aqueous solution, hydrolyzing the whey protein aqueous solution subjected to high-pressure homogenization in the presence of an enzyme, and performing enzyme deactivation, wherein in the step of performing high-pressure homogenization on the whey protein aqueous solution, the pressure of high-pressure homogenization is 150 to 450 MPa, and the time of high-pressure homogenization is 20 to 35 minutes. According to the method, protein feed liquid containing whey protein is subjected to high-pressure homogenization treatment before hydrolysis, so that alpha-helix, beta-fold and other protein secondary structures can be fully changed, the hydrolysis reaction time is greatly shortened, the bitter taste of the whey protein hydrolysate can be improved, and the characteristics of a whey protein hydrolysate downstream product can be improved; the osmotic pressure of the formula milk is reduced, and the reconstituability of the formula milk powder is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of food, and particularly relates to a preparation method of hydrolyzed whey protein. BACKGROUND

[0002] Milk protein has always been considered as a high-quality protein source and is widely used in various industries such as food. It is known that whole protein is not easy to be digested and absorbed by the human body due to its large molecular weight, especially for patients with diseases, and therefore, in the existing food processing technology, the whole protein is hydrolyzed into small molecular polypeptides or amino acids by enzymolysis or other technologies to improve the digestion and absorption rate of the protein. However, in the process of preparing hydrolyzed protein, some undesirable flavors, especially bitter taste, are inevitably generated, which greatly affects the application range of the hydrolyzed protein.

[0003] In order to improve the undesirable flavor of the hydrolyzed protein, the prior art has carried out research.

[0004] Document 1 discloses a hydrolyzed protein debittering composition and its product, preparation and application; the composition contains short-chain fatty acids, medium-chain fatty acids and long-chain fatty acids, and the content of the medium-chain fatty acids is 0.2-4.7% and the content of the long-chain fatty acids is 95.1-99.4% based on 100% of the total mass of the short-chain fatty acids, the medium-chain fatty acids and the long-chain fatty acids, and the rest is the short-chain fatty acids; by adding the composition to the hydrolyzed protein, the bitter taste of the hydrolyzed protein can be reduced.

[0005] Document 2 discloses an enzymatic hydrolysis method of whey protein and a hydrolysis product, and the method comprises the steps of: adjusting the pH value of a whey protein aqueous solution to be hydrolyzed to a value suitable for proteinase hydrolysis, then performing heat treatment on the whey protein aqueous solution to denature the protein, and then adding a proteinase to perform hydrolysis, so as to obtain a protein hydrolysis product with low bitter taste.

[0006] Document 3 discloses a method for reducing the bitter taste of a hydrolyzed protein infant formula, and the method comprises the following steps: a) mixing a protein equivalent source, a carbohydrate source and a fat source to produce a solution; b) adjusting the pH of the solution to between about 6.5 and about 7.2, wherein the bitter taste of the formula is reduced; c) reducing the water content of the mixture to produce a powder; and d) mixing vitamins, minerals and the powder with reduced pH to produce an infant formula.

[0007] Reference documents:

[0008] Document 1: CN109845877B;

[0009] Document 2: CN101785521B;

[0010] Reference document 3: CN101848649B. SUMMARY

[0011] Problem to be solved by the invention

[0012] There are currently a variety of methods to improve the bitterness of hydrolyzed proteins, especially hydrolyzed milk proteins, mainly including separation, extraction, adsorption, masking, etc., but these methods have their own advantages and disadvantages, for example, separation can cause loss of amino acids, reducing the nutritional value of protein hydrolysates, and the additives or adsorbed residues required for adsorption and masking are not necessarily suitable for all populations, for example, the fatty acid substances used in the above-mentioned reference document 1 are not suitable for many people who are intolerant to oil and fat, and some additives may also not be used in specific foods such as infant foods. It can be seen that the above-mentioned methods still have limitations in the application of hydrolyzed protein debittering.

[0013] Although, there are also existing technologies to improve the bitterness of hydrolyzed proteins from the preparation process of hydrolyzed proteins, such as the above-mentioned reference documents 2-3, etc., but such research is still not sufficient, it usually only focuses on the flavor of hydrolyzed proteins, and does not pay attention to the changes in the application level of the hydrolysis process to the hydrolyzed protein products, for example, its influence on the characteristics of the downstream products of the hydrolyzed protein products.

[0014] In view of the above-mentioned problems of the prior art, the primary purpose of the present application is to provide a preparation method of hydrolyzed whey protein, which not only improves the bitterness of the hydrolyzed whey protein product, but also improves the characteristics of the downstream products of the hydrolyzed whey protein, including reducing the osmotic pressure of formula milk, improving the reconstitution of formula milk powder, etc.

[0015] Further, the purpose of the present application is also to provide a preparation method of formula milk powder, which includes or uses the preparation method of hydrolyzed whey protein provided by the present application.

[0016] Solution to the problem

[0017] It has been found that the above technical problems can be solved by implementing the following technical solutions:

[0018] [1] A preparation method of hydrolyzed whey protein, characterized in that,

[0019] The method comprises the following steps: a step of subjecting a whey protein aqueous solution to high-pressure homogenization, a step of subjecting the whey protein aqueous solution after high-pressure homogenization to hydrolysis in the presence of an enzyme, and a step of inactivating the enzyme.

[0020] Among them,

[0021] In the step of subjecting the aqueous solution of whey protein to high-pressure homogenization, the pressure of the high-pressure homogenization is 150-450 MPa, and the time of the high-pressure homogenization is 20-35 min.

[0022] [2] The method according to [1], characterized in that,

[0023] The solid content of the aqueous solution of whey protein is 11 mass% or less.

[0024] [3] The method according to [1] or [2], characterized in that,

[0025] Before the high-pressure homogenization, the aqueous solution of whey protein is subjected to heat history, and the temperature of the heat history is 55-60°C.

[0026] [4] The method according to any one of [1] to [3], characterized in that,

[0027] Before the hydrolysis, the method further comprises a step of adjusting the pH of the aqueous solution of whey protein after the high-pressure homogenization, and the end point of the pH adjustment is 6.5-8.0.

[0028] [5] The method according to any one of [1] to [4], characterized in that,

[0029] The enzyme is one or more of alkaline protease, acid protease, neutral protease, trypsin, pepsin, protein deamidase, flavor protease, aminopeptidase, and carboxypeptidase.

[0030] [6] The method according to any one of [1] to [5], characterized in that,

[0031] The amount of the enzyme added is 2-3 mass% of the protein content in the aqueous solution of whey protein.

[0032] [7] The method according to any one of [1] to [6], characterized in that,

[0033] The time of the hydrolysis is 25-65 min, and the temperature of the hydrolysis is 55±2°C.

[0034] [8] The method according to any one of [1] to [7], characterized in that,

[0035] The temperature of the enzyme inactivation is 110±5°C, and the time of the enzyme inactivation is 20±3 s.

[0036] [9] A method for preparing a formula milk powder, characterized in that,

[0037] The method comprises the method for preparing hydrolyzed whey protein according to any one of 1 to 8.

[0038]

[10] The production method according to [9], characterized by

[0039] The method includes a step of spray drying.

[0040] Effects of the invention

[0041] Through implementation of the technical solutions, the application has the following beneficial effects:

[0042] The application provides a preparation method of hydrolyzed whey protein. The protein solution containing whey protein is subjected to high-pressure homogenization treatment before hydrolysis, so that the secondary structure of the protein, such as α-helix and β-fold, is fully changed to be rapidly exposed, and then the protein is contacted with the enzyme, so that the hydrolysis reaction time can be greatly shortened. The bitterness of the hydrolyzed whey protein can be improved, and the characteristics of the downstream product of the hydrolyzed whey protein can be improved, including reducing the osmotic pressure of formula milk, improving the reconstitution of formula milk powder, such as insolubility index, and the like. In actual production, the hydrolysis time is shortened, and the energy consumption is also reduced. The method for preparing hydrolyzed whey protein provided by the application not only greatly improves the production efficiency, but also can obtain high-quality hydrolyzed whey protein product. The product is particularly suitable for preparing formula milk products, especially infant formula milk products. DETAILED DESCRIPTION

[0043] Embodiments of the present application are described below, but the present application is not limited thereto. The present application is not limited to each configuration described below, and various modifications can be made within the scope of the present application, and embodiments obtained by appropriately combining the technical means disclosed in each of the different embodiments and examples are also included in the technical scope of the present application.

[0044] I. Definition of Terms

[0045] In the present application, "comprising", "having", "including" or "containing" can mean including or open-ended, and does not exclude additional, unrecited elements or method steps. At the same time, "comprising", "having", "including" or "containing" can also mean closed, excluding additional, unrecited elements or method steps.

[0046] In the present application, "may" means both performing a certain process and not performing a certain process.

[0047] In the present application, "optional" or "optionally" means that a certain substance, component, execution step, applied condition, etc. is used or not used.

[0048] In the present application, the numerical range represented by "numerical value A to numerical value B", "numerical value A - numerical value B", "numerical value A or more / less" means a range including the end point values A and B.

[0049] In the present application, "about" is used to qualify the numerical ranges and parameters of the present application as being approximate, and the numerical values given in the specific examples are as precise as possible. Unless otherwise indicated, all ranges, numbers, values and percentages are understood to be modified in all instances by the term "about". Herein, "about" generally means within ±5%, ±3%, ±1% or ±0.5% of a given value or range. Also, the numerical values, numerical ranges, should be understood to include systemically error inherent in the manufacturing process.

[0050] In the present application, "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments" and the like mean that the particular element (e.g., feature, structure, property and / or characteristic) described is included in at least one embodiment of what is described herein, and can or can not be present in other embodiments. In addition, it should be understood that the elements as described can be combined in any suitable manner in the various embodiments.

[0051] In the present application, the unit names used are international standard unit names, and if not specifically stated, the "%" used means the weight or mass percentage content.

[0052] In the present application, "infants" means the human population group under the age of 3 years, which includes infants from 0 to 6 months of age, older infants from 6 to 12 months of age and toddlers from 12 to 36 months of age.

[0053] In the present application, "children" means the human population group in the growth and development period, aged more than 3 years and less than 12 years.

[0054] In the present application, "adolescents" means the human population group in the growth and development period, aged more than 12 years and less than 18 years.

[0055] In the present application, "middle-aged and elderly" means the human population group aged more than 45 years.

[0056] In the present application, "animal milk" means the liquid obtained from the mammary glands of mammals in the lactation period. The term "animal milk" should be interpreted broadly and encompasses both raw milk (i.e., the liquid obtained directly from the mammary glands) and standardized dairy products (such as, for example, skimmed milk or whole milk).

[0057] II. Method for preparing hydrolysed whey proteins

[0058] The present application provides a method for preparing hydrolyzed whey protein, the method comprising the steps of: a step of subjecting a whey protein aqueous solution to high-pressure homogenization, a step of subjecting the whey protein aqueous solution after high-pressure homogenization to hydrolysis in the presence of an enzyme, and a step of inactivating the enzyme.

[0059] First, the source of the whey protein used as a raw material in the present application is not particularly limited in principle, and can be, for example, whey protein derived from various animal milk such as cow milk, goat milk, horse milk, camel milk, etc., and preferably, can be derived from cow milk.

[0060] Further, the method for separating or purifying whey from the above-described animal milk is not particularly limited, and in some specific embodiments, the above-described separation or purification means includes a defatting treatment to separate a fat component from the animal milk raw material. The method for defatting is not particularly limited in principle, and can be performed by centrifugation or the like. By the defatting treatment, at least 90% by mass or more, preferably 92% by mass or more, and more preferably 95% by mass or more of the total fat of the animal milk raw material is separated.

[0061] In some specific embodiments, the above-described separation or purification further includes separation of protein from the raw material milk (which has been subjected to the defatting treatment). The separation of protein is mainly separation of casein. The method for separating casein is not particularly limited. For example, the separation can be performed by adjusting the pH of the raw material milk to cause the casein to coagulate and precipitate around the isoelectric point by adding an acidic substance (acid whey), or by adding a coagulant, a fermenting agent, or the like to the raw material milk to separate the whey component while forming cheese (sweet whey). In addition, in other specific embodiments, the whey protein raw material of the present application can be obtained by using a filter membrane of a suitable pore size to trap and separate protein components of different molecular weights by membrane filtration.

[0062] More specifically, the above-described step of separating the whey protein can include a desalting and concentration step. That is, the component enriched with the whey protein can be subjected to a desalting and optional concentration treatment after the defatting and protein separation. The desalting treatment is not particularly limited in principle, and can be performed by, for example, membrane filtration (nanofiltration (NF) and / or electrodialysis) or the like. In some preferred embodiments, by the desalting treatment, 70% by mass or more of inorganic salts, preferably 80% by mass or more, and more preferably 90% by mass or more can be removed. The concentration step can be performed simultaneously with or after the desalting, and can typically be performed by, for example, ultrafiltration, diafiltration, or reverse osmosis to obtain a whey protein raw material with a higher protein content.

[0063] The whey protein-containing component obtained by each of the above-mentioned processes can be further dried to obtain whey protein solids, typically in the form of a whey protein powder, for example by spray drying.

[0064] In addition, the whey protein material of the present application can be prepared by the above-mentioned processes or purchased from commercial sources, for example, commercially available whey protein concentrate powder, whey protein isolate powder, desalted whey protein powder, whey protein liquid, and the like.

[0065] The content of whey protein in the whey protein material of the present application is not particularly limited and is related to the preparation method of the whey protein material. In some embodiments, the content of whey protein in the whey protein material (e.g., based on the total dry weight of the whey protein material) can be 50 mass% or more, preferably 65 mass% or more, more preferably 80 mass% or more, for example, 80 mass%, 81 mass%, 82 mass%, 83 mass%, 84 mass%, 85 mass%, and the like.

[0066] In addition, the whey protein material of the present application is preferably an intact protein material that has not been subjected to degradation treatment.

[0067] Further, after obtaining the whey protein material described above, it can be mixed with water to form a whey protein aqueous solution. In some preferred embodiments, the solids content of the whey protein aqueous solution can be 11 mass% or less, preferably 9-11 mass%, for example, 9 mass%, 9.5 mass%, 10 mass%, 10.5 mass%, 11 mass%, and the like, from the perspective of facilitating high-pressure homogenization and sufficient hydrolysis described below.

[0068] From the perspective of facilitating the formation of a uniform whey protein aqueous solution, which in turn facilitates high-pressure homogenization and sufficient hydrolysis described below, in some preferred embodiments, the whey protein material is heated when mixed with water, i.e., the whey protein aqueous solution has a thermal history before high-pressure homogenization, and the thermal history temperature is 55-60°C, for example, 55°C, 55.5°C, 56°C, 56.5°C, 57°C, 57.5°C, 58°C, 58.5°C, 59°C, 59.5°C, 60°C, and the like.

[0069] Further, after obtaining the whey protein aqueous solution, high pressure homogenization is performed. In some preferred embodiments, the pressure of the high pressure homogenization is 150-450 MPa, preferably 200-400 MPa, for example, it can be 200 MPa, 210 MPa, 220 MPa, 230 MPa, 240 MPa, 250 MPa, 260 MPa, 270 MPa, 280 MPa, 290 MPa, 300 MPa, 310 MPa, 320 MPa, 330 MPa, 340 MPa, 350 MPa, 360 MPa, 370 MPa, 380 MPa, 290 MPa, 400 MPa; the time of the high pressure homogenization is 20-35 min, preferably 20-30 min, for example, it can be 20 min, 21 min, 22 min, 23 min, 24 min, 25 min, 26 min, 27 min, 28 min, 29 min, 30 min, etc.

[0070] The present application finds that by performing high pressure homogenization on the whey protein aqueous solution before hydrolysis, the secondary structure of the protein such as α-helix, β-sheet, etc. can be changed substantially, so that it is exposed rapidly and the hydrolysis reaction time can be greatly reduced after contacting with the enzyme, thereby helping to improve the bitter taste of the hydrolyzed whey protein.

[0071] Further, the whey protein aqueous solution after high pressure homogenization is hydrolyzed in the presence of an enzyme. In order to make the enzyme play an excellent role, before hydrolysis, a buffering component can be used to adjust the pH of the whey protein aqueous solution after high pressure homogenization, preferably, the pH adjustment end point is 6.5-8.0. The kind of such buffering component is not particularly limited in principle, as long as it meets the provisions of food safety laws and regulations, typically, one or more of alkali metal carbonates, bicarbonates, phosphates, (mono or di) hydrogen phosphates, or alkali metal hydroxides, etc. can be listed.

[0072] The enzyme that can be used in the present application is not particularly limited in principle, in some specific embodiments, the enzyme can be one or more of alkaline protease, acid protease, neutral protease, trypsin, pepsin, protein deamidase, flavour protease, aminopeptidase, carboxypeptidase. For these enzymes, they can be obtained by commercial purchase, for example, they can be commercially available from Novozymes, Amano, DSM, etc. For the convenience of large-scale production, the present application chooses to use commercial enzymes, for example, Conc BG and Flavourzyme 500MG.

[0073] From the perspective of avoiding or inhibiting the undesirable taste (bitterness, etc.) caused by the hydrolysis of the exposed end amine group, etc., in some preferred embodiments, the enzyme used in the present application comprises alkaline protease and flavourzyme, preferably, the enzyme used in the present application consists of alkaline protease (Conc BG) and flavourzyme (Flavourzyme 500MG). For the mixing amount in the complex enzyme, in some embodiments, the ratio of the alkaline protease (Conc BG) and flavourzyme (Flavourzyme 500MG) is 1 : (8-15), for example, it can be 1 :8, 1 :9, 1 :10, 1 :11, 1 :12, 1 :13, 1 :14, 1 :15, etc.

[0074] Further, for the total amount of the above-mentioned (complex) enzyme, in principle, there is no particular limitation, and it can be determined according to the conventional amount corresponding to the characteristics of each enzyme in the art. From the perspective of hydrolysis efficiency, in some preferred embodiments, the total amount of enzyme can be used at 2-3% by mass of the protein content in the whey protein aqueous solution, for example, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%, etc.

[0075] Further, for the hydrolysis temperature, the hydrolysis can be carried out at 55±2°C. In addition, since the appropriate high-pressure homogenization treatment is carried out before hydrolysis, the hydrolysis time can be shortened, and the preferred hydrolysis time can be 25-65 min, more preferably 30-60 min, for example, it can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0076] After the hydrolysis is completed, the hydrolyzate of whey protein can be subjected to enzyme inactivation treatment. For the enzyme inactivation treatment, there is no particular limitation, for example, it can be carried out using the high-temperature inactivation method, and in some specific embodiments, the enzyme inactivation temperature can be 110±5°C, and the enzyme inactivation time can be 20±3s.

[0077] In addition, in the preparation method of the hydrolyzed whey protein according to the present application, in addition to the above-mentioned steps of high-pressure homogenization of the whey protein aqueous solution, hydrolysis of the high-pressure homogenized whey protein aqueous solution in the presence of an enzyme, and enzyme inactivation, optionally, it can also include the steps of sterilization, concentration, and drying, etc.

[0078] III. Preparation method of formula milk powder

[0079] The present application provides a method for preparing a formula milk powder, which comprises the method for preparing the hydrolyzed whey protein product as described above.

[0080] In some embodiments, the method for preparing the formula milk powder of the present application comprises a step of spray drying. In some specific embodiments, the inlet temperature of the spray drying is 160-180°C, and the outlet temperature is 85-90°C.

[0081] Formula milk powder needs to be subjected to high temperature such as spray drying for final shaping, which can cause denaturation or aggregation of proteins, and thus can result in reduced solubility of the final product. However, the present application has found that, under the same raw materials and preparation process, the formula milk powder added with the hydrolyzed whey protein product prepared by the method as described above still has good solubility even after high temperature treatment such as spray drying.

[0082] In addition to the hydrolyzed whey protein product prepared by the method as described above, the formula milk powder of the present application can further comprise any one or more of other components such as other protein components, carbohydrate components, oil components, mineral components, vitamin components, nucleotide components, and probiotic components.

[0083] The formula milk powder of the present application is not particularly limited in terms of the target subject, and can be, for example, an infant formula milk powder, a children formula milk powder, an adolescent formula milk powder, or a middle-aged or elderly formula milk powder.

[0084] Examples

[0085] The embodiments of the present application will be described in detail below with reference to examples, but those skilled in the art will understand that the following examples are only for illustration of the present application and should not be regarded as limiting the scope of the present application. In the examples, the specific conditions not mentioned are performed according to the conventional conditions or the conditions recommended by the manufacturers. The materials or instruments used are commercially available conventional products unless otherwise specified.

[0086] Experimental materials:

[0087] Whey protein: concentrated whey protein powder with a protein content of about 85% by dry weight;

[0088] Alkaline protease: Conc. BG (enzyme activity 12.5-14.0 AU-A / g);

[0089] Flavourzyme: Flavourzyme 500MG (enzyme activity 500-600 LAPU / g).

[0090] Example 1

[0091] The whey protein was dissolved at a temperature of 57.5°C and a concentration of 10.0% (w / w). Potassium hydroxide was added to adjust the pH to 7.0, and alkaline protease and flavourzyme were added (the enzyme addition ratio was 2% of the protein concentration in the feed liquid, and the mass ratio of the two enzymes was 3:7). Hydrolysis was started at a temperature of 54.8°C, and the enzymes were inactivated after 90 min. The temperature for inactivating the enzymes was 110°C for 20 s, and a protein hydrolysis feed liquid was obtained.

[0092] Comparative Example 1

[0093] The whey protein was dissolved at a temperature of 58.2°C and a concentration of 10.5% (w / w). Homogenization was performed at a pressure of 100 MPa for 15 min, and after homogenization, potassium hydroxide was added to adjust the pH to 6.8. Alkaline protease and flavourzyme were added (the enzyme addition ratio was 2.2% of the protein concentration in the feed liquid, and the mass ratio of the two enzymes was 2:8). Hydrolysis was started at a temperature of 55.0°C, and the enzymes were inactivated after 75 min. The temperature for inactivating the enzymes was 106°C for 20 s, and a protein hydrolysis feed liquid was obtained.

[0094] Comparative Example 2

[0095] The whey protein was dissolved at a temperature of 58.4°C and a concentration of 10.5% (w / w). Homogenization was performed at a pressure of 50 MPa for 18 min, and after homogenization, potassium hydroxide was added to adjust the pH to 6.9. Alkaline protease and flavourzyme were added (the enzyme addition ratio was 2.2% of the protein concentration in the feed liquid, and the mass ratio of the two enzymes was 3:8). Hydrolysis was started at a temperature of 55.3°C, and the enzymes were inactivated after 90 min. The temperature for inactivating the enzymes was 110°C for 21 s, and a protein hydrolysis feed liquid was obtained.

[0096] Comparative Example 3

[0097] The whey protein was dissolved at a temperature of 57.6°C and a concentration of 10.5% (w / w). Homogenization was performed at a pressure of 500 MPa for 12 min, and after homogenization, potassium hydroxide was added to adjust the pH to 7.2. Alkaline protease and flavourzyme were added (the enzyme addition ratio was 2.2% of the protein concentration in the feed liquid, and the mass ratio of the two enzymes was 5:8). Hydrolysis was started at a temperature of 55.5°C, and the enzymes were inactivated after 15 min. The temperature for inactivating the enzymes was 112°C for 20 s, and a protein hydrolysis feed liquid was obtained.

[0098] Example 1

[0099] The whey protein was dissolved at a temperature of 57.8°C and a concentration of 10.5% (w / w). Homogenization was performed at a pressure of 300 MPa for 25 min. After homogenization, potassium hydroxide was added to adjust the pH to 7.0. Alkaline protease and flavourzyme were added at a ratio of 2.2% of the protein concentration in the solution, and the mass ratio of the two enzymes was 1:8. Hydrolysis was started at a temperature of 55.1°C, and the enzymes were inactivated after 30 min. The temperature for inactivating the enzymes was 113°C, and the time was 21 s. The protein hydrolysis solution was obtained.

[0100] Example 2

[0101] The whey protein was dissolved at a temperature of 56.9°C and a concentration of 10.5% (w / w). Homogenization was performed at a pressure of 200 MPa for 30 min. After homogenization, potassium hydroxide was added to adjust the pH to 7.1. Alkaline protease and flavourzyme were added at a ratio of 2.2% of the protein concentration in the solution, and the mass ratio of the two enzymes was 1:10. Hydrolysis was started at a temperature of 55.2°C, and the enzymes were inactivated after 60 min. The temperature for inactivating the enzymes was 111°C, and the time was 20 s. The protein hydrolysis solution was obtained.

[0102] Example 3

[0103] The whey protein was dissolved at a temperature of 59.1°C and a concentration of 10.5% (w / w). Homogenization was performed at a pressure of 400 MPa for 20 min. After homogenization, potassium hydroxide was added to adjust the pH to 7.2. Alkaline protease and flavourzyme were added at a ratio of 2.2% of the protein concentration in the solution, and the mass ratio of the two enzymes was 1:15. Hydrolysis was started at a temperature of 55.6°C, and the enzymes were inactivated after 40 min. The temperature for inactivating the enzymes was 110°C, and the time was 22 s. The protein hydrolysis solution was obtained.

[0104] Example 4

[0105] The whey protein was dissolved at a temperature of 57.7°C and a concentration of 10.5% (w / w). Homogenization was performed at a pressure of 350 MPa for 25 min. After homogenization, potassium hydroxide was added to adjust the pH to 7.1. Alkaline protease and flavourzyme were added at a ratio of 2.2% of the protein concentration in the solution, and the mass ratio of the two enzymes was 1:12. Hydrolysis was started at a temperature of 55.4°C, and the enzymes were inactivated after 60 min. The temperature for inactivating the enzymes was 109°C, and the time was 21 s. The protein hydrolysis solution was obtained.

[0106] Experimental Example 1

[0107] The taste of the samples prepared in the above-mentioned control group, Comparative Examples 1-3 and Example 1-4 was evaluated: quinine was prepared into solutions with concentrations of 12.5 μmol / L and 62.5 μmol / L, respectively, and the bitterness was defined as 1 and 10, respectively. The bitterness value of the sample was tested, and each sample was evaluated by 10 people. The test was repeated three times, and the results were expressed as mean ± standard deviation. The experimental results are shown in Table 1 below.

[0108] Table 1

[0109]

[0110] Experimental Example 2

[0111] Osmotic pressure is a commonly used medical indicator and is closely related to human health. The kidneys of infants are not fully developed and their physiological functions are not perfect. If they are fed with high-osmotic-pressure formula food for a long time, the probability of kidney function damage increases. The osmotic pressure of breast milk is about 292-300 mOsm / kg. Generally speaking, liquid formula milk with an osmotic pressure > 300 mOsm / kg is called high-osmotic-pressure formula milk; and formula milk with an osmotic pressure of 280-300 mOsm / kg is called isotonic formula milk.

[0112] Maltodextrin / lactose, edible plant blend oil were used as main raw materials, and the protein hydrolysis liquor prepared in the above-mentioned control group, Comparative Examples 1-3 and Example 1-4 (added in an amount of 27% of the energy supply ratio of the formula) and other ingredients were added, mixed uniformly, homogenized, sterilized, then concentrated, spray dried, and different formula milk powder samples were prepared. The main process parameters were: homogenization 25 MPa; sterilization (88-90°C, 15s); spray drying (inlet air temperature 160-180°C, outlet air temperature 85-90°C).

[0113] The osmotic pressure of the different samples prepared was detected by an osmotic pressure instrument (12.9 g of formula milk powder sample + 90 g of water were mixed to prepare a solution), and each sample was detected 3 times. The experimental results are shown in Table 2 below.

[0114] Table 2

[0115]

[0116] Experimental Example 3

[0117] Insolubility Index is a core index for measuring the solubility of milk powder. The lower the value, the more fully the milk powder is dissolved, and the finer and more uniform the particles are. The higher the value, the worse the solubility, and there may be protein or fat aggregates that are not completely dispersed. This index is directly related to the mixing experience of milk powder and the digestion and absorption of infants.

[0118] The protein hydrolysis liquor prepared in the above control group, Comparative Examples 1-3 and Example 1-4 was prepared into different formula milk powder samples in the same manner as in Experimental Example 2.

[0119] The different samples prepared were subjected to insolubility index detection according to GB 5413.29-2010, and each sample was detected 3 times. The experimental results are shown in Table 3 below. The results in Table 3 show that homogenization before protein hydrolysis can significantly improve the dissolution efficiency.

[0120] Table 3

[0121]

Claims

1. A method for preparing hydrolyzed whey protein, characterized in that, The method includes the following steps: high-pressure homogenization of whey protein aqueous solution, hydrolysis of the high-pressure homogenized whey protein aqueous solution in the presence of enzymes, and enzyme inactivation. in, In the step of high-pressure homogenization of whey protein aqueous solution, the pressure of high-pressure homogenization is 150-450 MPa, and the time of high-pressure homogenization is 20-35 min.

2. The method according to claim 1, characterized in that, The solids content of the whey protein aqueous solution is less than 11% by mass.

3. The method according to claim 1 or 2, characterized in that, Before high-pressure homogenization, the whey protein aqueous solution undergoes a thermal experience at a temperature of 55-60°C.

4. The method according to any one of claims 1-3, characterized in that, Before hydrolysis, the method further includes a step of adjusting the pH of the high-pressure homogenized whey protein aqueous solution, with the pH adjustment endpoint being 6.5-8.

0.

5. The method according to any one of claims 1-4, characterized in that, The enzyme is one or more of the following: alkaline protease, acidic protease, neutral protease, trypsin, pepsin, protein deamidase, flavor protease, aminopeptidase, and carboxypeptidase.

6. The method according to any one of claims 1-5, characterized in that, The amount of enzyme added is 2-3 times the mass of the protein content in the whey protein aqueous solution.

7. The method according to any one of claims 1-6, characterized in that, The hydrolysis time is 25-65 min, and the hydrolysis temperature is 55±2℃.

8. The method according to any one of claims 1-7, characterized in that, The enzyme inactivation temperature is 110±5℃, and the enzyme inactivation time is 20±3s.

9. A method for preparing formula milk powder, characterized in that, The method includes the method for preparing hydrolyzed whey protein according to any one of claims 1-8.

10. The preparation method according to claim 9, characterized in that, The method includes a spray drying step.

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