Method for preparing whey protein

Abstract

The present invention relates to a method for producing whey protein, the method comprising a hydrolysis step and an enzyme inactivation step, wherein in the hydrolysis step, a whey protein aqueous solution is hydrolyzed in the presence of an enzyme, the hydrolysis temperature is 55°C or lower, the hydrolysis time is 60 minutes or less, and the whey protein aqueous solution is subjected to heat history at a temperature of not more than 40°C before the hydrolysis, and before the end of the hydrolysis, lactose is added to a system containing a whey protein hydrolysis component, the amount of the lactose added being 15% to 300% by mass of the whey protein content; and in the enzyme inactivation step, after the end of the hydrolysis, the hydrolyzate solution is heated to inactivate the enzyme after adjusting the pH to 7.2 to 8.0.

Description

Technical Field

[0001] This invention belongs to the food field and relates to a method for preparing protein products, specifically a method for processing and preparing whey protein. Background Technology

[0002] Cow's milk is the main raw material for producing infant formula and is also one of the first allergens that infants come into contact with. Food protein allergy is an inappropriate immune response of infants to proteins in food. Since milk is the main food for infants in their early years, milk protein allergy is the most common food protein allergy after birth.

[0003] The incidence of cow's milk protein allergy in infants is 2%–6%, with clinical manifestations including angioedema, urticaria, atopic dermatitis, respiratory symptoms, diarrhea, vomiting, and colic. Cow's milk contains more than 20 proteins, all of which have potential allergenicity. However, β-lactoglobulin is currently widely considered the main allergen. Since β-lactoglobulin is primarily found in whey protein, its content can be reduced by hydrolyzing whey protein. Hydrolyzed whey protein is composed of amino acids, oligopeptides, and polypeptides, and is a pre-digested protein. Hydrolyzed whey protein reduces the antigenicity of milk proteins; the higher the degree of hydrolysis, the lower the antigenicity. Moderate hydrolysis of whey protein can induce tolerance to milk proteins in infants.

[0004] Hydrolyzed whey protein is widely used in special medical purpose foods, sports foods, and health foods due to its low allergenicity, easy digestibility, residue-free nature, and rich content of bioactive peptides. Currently, the main method used in the industry to reduce β-lactoglobulin content is through enzymatic hydrolysis technology, for example:

[0005] Reference 1 discloses a method for reducing β-lactoglobulin in concentrated whey protein powder through bio-compound enzymatic hydrolysis. The method involves dissolving 1.6–5.0% (w / w) of concentrated whey protein powder in water, maintaining the temperature at 50–100°C for 20–60 min, and then cooling to 45°C. Subsequently, the concentrated whey protein powder and a compound enzyme are added to the whey protein solution at a mass ratio of 40–80:1, and enzymatic hydrolysis is performed at 30–45°C for 3–8 hours. After hydrolysis, the solution is sterilized at 100–125°C for 90–180 s. Following sterilization, the solution is concentrated at 50–85°C, resulting in a solids concentration of 20–35%. Finally, the concentrated solution is spray-dried at a hot air inlet temperature of 200–210°C and a temperature of 80–90°C, while the solution temperature is 65–75°C.

[0006] Reference 2 discloses a partially hydrolyzed whey protein powder and its preparation method. This invention involves preparing a 5%–10% whey protein aqueous solution from concentrated whey protein, incubating it at 55℃–85℃ for 5–10 minutes to denature the protein, then cooling the aqueous solution to the hydrolysis temperature, adding a complex protease at a protease to whey protein mass ratio of 0.4–0.9:100, and hydrolyzing at 50℃–55℃ for 2–4 hours. The complex protease consists of neutral protease F and neutral protein. Enzyme G, or a mixture of neutral protease F and neutral protease P in a mass ratio of 3–8:1, is used. After hydrolysis, the pH of the solution is adjusted to 6.7–6.9, and the hydrolysis reaction is terminated by heat treatment at 80℃–95℃ for 5–10 min to inactivate the enzyme. The solution after terminating the hydrolysis reaction is concentrated by nanofiltration, and the solid content after concentration is 20%–35%. The concentrate is then spray-dried, with the feed temperature at 20℃–25℃ and the hot air inlet temperature at 135℃–175℃.

[0007] In addition, there are other processes for the pre-modification of whey protein. For example, reference 3 provides a method for producing modified whey protein with improved thermal stability without the use of organic solvents or other additives, and the modified whey protein produced by this method. The manufacturing method involves contacting and mixing a whey protein solution with a whey protein solution that is rotated into a thin-film cylindrical shape, and mixing the mixture at a temperature within the range of 76–120°C for 5,000 seconds. -1 ~25,000s -1 The shear rate was 8 minutes to 0.1 seconds. However, its related effects on hydrolyzed whey protein were not discussed.

[0008] Although the above-mentioned attempts have been made in the existing technology for processing whey protein, there is still room for further improvement in order to provide a more efficient and higher quality whey protein product.

[0009] References:

[0010] Reference 1: CN 102940126 A

[0011] Reference 2: CN 107136295 A

[0012] Reference 3: CN 101959423 A Summary of the Invention

[0013] The problem the invention aims to solve

[0014] As mentioned above, in the prior art, considering that spray drying is the common method for preparing the final hydrolyzed whey protein powder, this process requires heating the whey protein system to above 100°C or even higher. Although the time is short, there is still a concern about the thermal denaturation of protein components, which can easily lead to increased viscosity and gelation, thereby reducing nutritional value and reconstitution usability.

[0015] Therefore, pre-modification treatment is used in the hydrolysis preparation of whey protein to reduce the adverse effects on protein components during spray drying.

[0016] However, long-term practice has revealed that one of their drawbacks is the long pre-modification treatment time. For example, in reference 1, the denaturation treatment of the concentrated whey protein solution involves incubation at 50℃~100℃ for 20-60 minutes. Similarly, in reference 2, the whey protein aqueous solution is denatured at 55℃~85℃ for 5-10 minutes. This increases energy consumption and prolongs production time, and from a microbiological control perspective, it is not conducive to the control of thermophilic bacteria. A second drawback is that heat treatment denaturation of the whey protein solution destroys the whey protein molecular structure, reduces solubility, and hinders enzymatic hydrolysis. Furthermore, enzymatic hydrolysis easily produces denatured protein particles. Therefore, to achieve the target degree of hydrolysis and molecular weight distribution, the hydrolysis time will be prolonged. Reference 1 states that the hydrolysis time is 3-8 hours, and Reference 2 states that the hydrolysis time is 2-4 hours. Prolonged hydrolysis inevitably leads to increased energy consumption and extended production cycle. In addition, the increase in insoluble particles will also cause undesirable deposition on the membrane surface during concentration, resulting in reduced concentration efficiency. The third disadvantage is that the solid content after concentration is below 35%. Spray drying of low solid content feed solution results in smaller particle size, lower product yield, and higher energy consumption for product preparation and spray drying, leading to low production capacity.

[0017] In addition, other methods for modifying whey protein, such as those mentioned in reference 3, are proposed, but they are not specifically for hydrolyzed whey protein. Furthermore, these methods still require relatively high heat treatment temperatures during pre-modification.

[0018] In view of the problems of the prior art, the primary objective of this invention is to provide a method for preparing hydrolyzed whey protein. In this method, the whey protein aqueous solution is not pre-denatured; the whey protein is fully hydrated and then hydrolyzed at a certain temperature, shortening the hydrolysis time to less than 60 minutes. Furthermore, this invention uses lactose to cross-link with whey protein via glycosylation, improving the protein's thermal stability. Moreover, the enzyme inactivation process employs pH protection, adjusting the pH of the hydrolysate to the range of 7.2–8.0, ensuring uniformity and no denaturation of the hydrolysate while inactivating the enzyme. Additionally, glycosylation modification can improve protein solubility, resulting in a concentrated solution with a solid content of 35–45%, a larger particle size, good reconstitution properties, higher production capacity, and lower energy consumption.

[0019] Furthermore, the present invention aims to provide a method for preparing infant formula milk powder, which includes or uses the method for preparing hydrolyzed whey protein provided by the present invention.

[0020] Solution for solving the problem

[0021] It has been found that the above-mentioned technical problems can be solved by implementing the following technical solutions:

[0022] [1]. This invention first provides a method for preparing whey protein products, wherein the method includes:

[0023] The steps of hydrolysis and enzyme inactivation,

[0024] in,

[0025] In the hydrolysis step, the whey protein aqueous solution is hydrolyzed in the presence of an enzyme, the hydrolysis temperature is below 55°C, and the hydrolysis time is below 60 minutes.

[0026] Furthermore, the whey protein aqueous solution undergoes a thermal process at a temperature not exceeding 40°C before hydrolysis.

[0027] Before the hydrolysis is completed, lactose is added to the system containing the hydrolyzed whey protein components, wherein the amount of lactose added is 15% to 300% by mass of the whey protein content.

[0028] In the enzyme inactivation step, after the hydrolysis is completed, the pH of the hydrolysate solution is adjusted to 7.2-8.0 before heating to inactivate the enzyme.

[0029] [2]. According to the method of [1], wherein, in the hydrolysis step, the solid content of the whey protein aqueous solution is less than 18% by mass; and the carbohydrate content in the whey protein aqueous solution, based on the dry weight of solids, is less than 10% by mass.

[0030] [3]. The method according to [1] or [2], wherein the enzyme is a combination enzyme of endopeptide and exopeptide.

[0031] [4]. The method according to any one of [1] to [3], wherein the pH of the hydrolysis system in the hydrolysis step is 6.5 to 7.5.

[0032] [5]. The method according to any one of [1] to [4], wherein in the step of inactivating enzyme, the temperature of heating to inactivate enzyme is 105 to 110°C and the time is less than 30 seconds.

[0033] [6]. The method according to any one of [1] to [5], wherein the method further includes a concentration step after the enzyme inactivation step.

[0034] [7]. According to the method of [6], wherein in the concentration step, the enzyme-inactivated hydrolysate solution is concentrated to a solid content greater than 35% by mass.

[0035] [8]. The method according to any one of [1] to [7], wherein lactose is added to the hydrolysis system 4 to 8 minutes before the end of the hydrolysis.

[0036] [9]. The method according to any one of [1] to [8], wherein the content of protein components with a molecular weight of less than 3000 Da in the whey protein product obtained by the method is more than 75% of the total protein.

[0037]

[10] . Furthermore, the present invention also provides a method for preparing infant formula milk powder, wherein the method includes the preparation method for preparing whey protein products according to any one of [1] to [9] above.

[0038] The effects of the invention

[0039] By implementing the above technical solution, the present invention can achieve the following technical effects:

[0040] 1) The method of the present invention does not require preheating modification of whey protein raw materials or whey protein solutions before hydrolysis, which can further mitigate the impact of thermal denaturation on whey protein hydrolysis and the quality of the final product.

[0041] 2) In this invention, lactose is added before the end of the hydrolysis process, so that lactose glycosylates the whey protein hydrolysate, which not only improves the stability of the hydrolysate and helps it resist high temperature denaturation during subsequent spray drying, but also increases the solubility of the hydrolysate.

[0042] 3) By using pH protection during the enzyme inactivation process, the pH of the enzyme hydrolysate is adjusted to the range of 7.2 to 8.0, ensuring that the enzyme hydrolysate is uniform and free from denaturation while inactivating the enzyme;

[0043] 4) Through the above method, not only is a higher concentration of spray-dryable solution obtained after concentration treatment, but the reconstitution properties of the obtained spray-dried powder are also good.

[0044] 5) The method of the present invention not only greatly improves production efficiency, but also produces high-quality hydrolyzed whey protein products, which are particularly suitable for the preparation of infant formula dairy products. Attached Figure Description

[0045] Figure 1 Photograph of the protein components after enzyme inactivation in Example 1;

[0046] Figure 2 Photographs of protein components after enzyme inactivation in Comparative Example 1;

[0047] Figure 3 : High performance liquid chromatogram of the product prepared in Example 2. Detailed Implementation

[0048] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. Numerous specific details are set forth in the following detailed description to better illustrate the invention. Those skilled in the art will understand that the invention can be practiced without certain specific details.

[0049] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0050] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0051] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0052] In this invention, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0053] In this invention, the terms "optional" or "optionally" are used to indicate the use or non-use of certain substances, components, execution steps, application conditions, etc.

[0054] In this invention, “Da” is used to represent the unit of molecular weight, “Dalton”.

[0055] In this invention, unless otherwise specified, "room temperature" generally refers to a temperature of 23±2℃.

[0056] In this invention, unless otherwise stated, "%" refers to weight or mass percentage.

[0057] In this invention, the mixed system formed by milk powder and water is referred to as a "solution", which can be a substantial microemulsion system.

[0058] In this instruction manual, "infants and toddlers" refers to the human group under the age of 3 years.

[0059] In this specification, for the convenience of describing fatty acid glycerides, the following characters are used to refer to different types of fatty acids:

[0060] Ca: Decanoic acid (C10:0); La: Lauric acid (C12:0); M: Myristic acid (C14:0); P: Palmitic acid (C16:0); S: Stearic acid (C18:0); O: Oleic acid (C18:1); L: Linoleic acid (C18:2); Ln: Linolenic acid (C18:3).

[0061] In this specification, for specific fatty acid esters, a combination of the above characters is used to represent the type of fatty acid glyceride, wherein the letter or letter combination in the middle position represents the fatty acid at the 2-position of glycerol. For example:

[0062] OPO represents 1,3-dioleoyl-2-palmitoyl triglyceride; OPL represents 1-oleoyl-2-palmitoyl-3-linoleoyl triglyceride.

[0063] In this specification, the terms "substantially" or "essentially" can mean that a value includes the standard deviation of the error of the apparatus or method used to measure that value. The numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains a standard deviation due to the aforementioned testing apparatus or method.

[0064] In this invention, the terms "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to the described embodiment that are included in at least one of the embodiments described herein, and may or may not be present in other embodiments. Furthermore, it should be understood that the elements may be combined in any suitable manner in various embodiments.

[0065] The present invention primarily provides a method for hydrolyzing whey protein, which includes hydrolyzing a whey protein solution in the presence of an enzyme, and adding lactose at the end of the hydrolysis reaction. The enzyme is further inactivated under specific pH conditions, followed by concentration and spray drying to obtain a hydrolyzed whey protein solid powder.

[0066] This invention is primarily based on the following insights:

[0067] Unlike the pre-heat modification methods in the prior art, the whey protein raw materials or whey protein solutions of this invention do not require pre-heat modification. Furthermore, it has been found that when whey protein is hydrolyzed in the presence of enzymes, the addition of lactose to glycosylate the whey protein hydrolysate increases the heat stability and solubility of the hydrolysate, which can improve the solid content of the solution during spray drying and inhibit the denaturing effect of high temperature on protein components.

[0068] In addition, by adjusting the pH of the system to a suitable range during enzyme inactivation, the adverse effects of high-temperature enzyme inactivation on protein components can be mitigated.

[0069] Specifically, the method for hydrolyzing whey protein according to the present invention mainly includes a hydrolysis step in the presence of an enzyme, an enzyme inactivation step, and other optional post-processing steps.

[0070] (Whey protein)

[0071] In principle, there are no particular restrictions on the source of whey protein used as a raw material in this invention. For example, it can be whey protein derived from various animal milks, such as cow's milk, sheep's milk, horse's milk, camel's milk, etc. Preferably, it can be derived from cow's milk.

[0072] Furthermore, there are no particular limitations on the methods for separating or purifying whey from the aforementioned animal milk. In some specific embodiments, the separation or purification methods include defatting to separate the fat components from the animal milk raw material. There are no particular limitations on the defatting method in principle; it can be carried out by methods such as centrifugation. Through defatting, at least 90% by mass, preferably 92% by mass, and more preferably 95% by mass, of the total fat in the animal milk raw material is separated.

[0073] In some specific embodiments, the above-mentioned separation or purification also includes the separation of proteins from the (defatted) raw milk. The separation of proteins primarily involves the separation of casein. There are no particular limitations on the method for separating casein. For example, it can be achieved by adjusting the pH of the raw milk, adding an acidic substance to cause casein to coagulate and precipitate near its isoelectric point, thereby achieving separation (acidic whey); or, by optionally adding coagulants, fermenting agents, or other components to the raw milk, the whey components can be separated simultaneously with cheese formation (sweetened whey). Additionally, in other specific embodiments, membrane filtration can be used, employing a filter membrane with a suitable pore size to retain and separate protein components of different molecular weights, thereby obtaining whey protein raw materials of the present invention with various compositions.

[0074] More specifically, the above-described steps for separating whey protein may include, for example, desalting and concentration. That is, after defatting and protein separation, the whey protein-enriched components may be desalted and optionally concentrated. There are no particular limitations on the desalting process; for example, it can be performed using membrane filtration (nanofiltration (NF) and / or electrodialysis). In some preferred embodiments, desalting can remove more than 70% by mass of inorganic salts, preferably more than 80% by mass, and more preferably more than 90% by mass of inorganic salts. The concentration step can be performed simultaneously with or after desalting, typically using ultrafiltration, washing filtration, or reverse osmosis to obtain, for example, whey protein raw materials with higher protein content.

[0075] The whey protein-containing components obtained from the various possible processes described above can be further dried to obtain whey protein solids. Typically, spray drying or similar methods can be used to obtain solid whey protein powder.

[0076] Furthermore, the whey protein raw material of this invention can be prepared in-house using the methods described above, or it can be purchased commercially, such as various commercially available concentrated whey protein powders, whey protein isolates, whey protein liquids, and other high-whey protein raw materials. Preferably, the whey protein raw material of this invention can be whey protein isolate.

[0077] There is no particular limitation on the whey protein content in the whey protein raw material of the present invention. This is related to the preparation method of the whey protein raw material described above. In some specific embodiments, the whey protein content in the whey protein raw material (e.g., based on the total dry weight of the whey protein raw material) can be 50% by mass or more, preferably 60-95% by mass, such as 65-90% by mass, 70-85% by mass, etc.

[0078] Furthermore, the whey protein raw material of the present invention, in addition to whey protein, optionally contains one or more of carbohydrates, fats, and inorganic salts. Carbohydrates may include polysaccharides, such as lactose or dietary fiber. In some specific embodiments, depending on the different purification methods for whey protein, the (dry) carbohydrate content, based on the total dry weight of the whey protein raw material, is 10% by mass or less, preferably 8% by mass or less, for example, 1-7% by mass, 2-6% by mass, etc.

[0079] In other preferred embodiments, particularly regarding lactose in the whey protein, the content can be controlled to a low range, which can be achieved through the separation and purification described above. Based on the total dry weight of the whey protein raw material, the lactose (dry) content is 8% by mass or less, preferably 5% by mass or less, for example, 1-4% by mass, 2-3% by mass, etc.

[0080] In addition, the whey protein raw material of the present invention can be a whole protein raw material that has not undergone any degradation treatment, or it can be a whey protein raw material that has undergone partial degradation treatment, but can still be further degraded as described below to achieve the whey protein raw material with the composition desired by the present invention.

[0081] Furthermore, after obtaining the whey protein raw material described above, it can be mixed with water before hydrolysis as described below to form a whey protein aqueous solution. In some preferred embodiments, the solid content of the whey protein aqueous solution can be less than 18% by mass, for example, 5-16% by mass, 8-13% by mass, etc., to facilitate sufficient hydrolysis as described below.

[0082] For the whey protein raw material of the present invention, the heat experience it undergoes after separation from animal milk (e.g., solid (powder)) or before hydrolysis of the whey protein aqueous solution formed therefrom does not exceed 40°C, preferably the heat experience temperature is 20 to 35°C.

[0083] (Hydrolysis of whey protein)

[0084] The hydrolysis of whey protein in this invention is an enzymatic hydrolysis performed in the presence of an enzyme.

[0085] There are no particular limitations in principle regarding the enzymes that can be used in this invention. In some specific embodiments of this invention, these enzymes can be selected from one or more of various endopeptidases or exopeptidases. Examples of endopeptidases that can be used in this invention include one or more of papain, alkaline protease, trypsin, pepsin, acidic protease, neutral protease, and complex protease (Protamex 1.6). Examples of exopeptidases that can be used include one or more of protein deamidases, flavor enzymes (Flavourzyme 500MG), aminopeptidases, and carboxypeptidases in some specific embodiments. These enzymes are commercially available, for example, from companies such as Novozymes, Amano, and DSM.

[0086] To improve hydrolysis efficiency and avoid or suppress undesirable flavors (bitterness, etc.) resulting from the exposure of terminal amine groups during hydrolysis, the enzymes used in this invention can be complex enzymes comprising endopeptides and exopeptides. More preferably, the complex enzyme can be formed by combining the aforementioned mixed protease as an endopeptide with a flavor protease as an exopeptide. Regarding the amount of complex enzyme, in some preferred embodiments, the mass ratio of endopeptide to exopeptide can be 1.5–2.5:2.5–3.5.

[0087] Furthermore, there is no particular limitation on the total amount of the above (compound) enzymes in principle, and it can be determined according to the conventional dosage corresponding to the characteristics of each enzyme in the art. In some preferred embodiments, the total amount of enzymes can be used at 1 to 4% by mass of whey protein (dry weight), for example, 1.6 to 3% by mass.

[0088] Furthermore, there are no particular restrictions on other conditions for the aforementioned hydrolysis. Buffering agents can be used to adjust the pH of the whey protein solution system, for example, to a range of 6.8 to 7.2, depending on the enzymes used. There are no particular restrictions on the types of such buffering agents, as long as they comply with food safety laws and regulations. Typical examples include one or more of alkali metal carbonates, bicarbonates, phosphates, hydrogen phosphates (mono or di), or alkali metal hydroxides.

[0089] Furthermore, the hydrolysis temperature can be carried out at a temperature not exceeding 55°C, preferably 45–55°C, such as 48°C or 50°C. Additionally, the hydrolysis time can be 0.5–1 hour, preferably 0.7–1 hour.

[0090] During the hydrolysis process described above, it has been found that the addition of lactose can promote the glycosylation reaction of whey protein hydrolysates. This reaction not only improves the heat stability of the hydrolysates but also enhances their water solubility, significantly increasing the solid content of the solution during spray drying, as will be described below. In particular, because lactose is added during the hydrolysis process of this invention, whey protein hydrolysates with better solubility can be obtained in a shorter time.

[0091] Regarding the amount of lactose added, in some preferred embodiments, from the perspective of fully carrying out the glycosylation reaction, the amount of lactose added (on dry weight) is 15% to 300% by mass of the total whey protein component in the whey protein aqueous solution, preferably 20% to 250% by mass, more preferably 30% to 200% by mass, for example 40% by mass, 50% by mass, 60% by mass, 70% by mass, 80% by mass, 90% by mass, 100% by mass, 110% by mass, 120% by mass, 150% by mass, 170% by mass, etc.

[0092] In addition, there are no particular restrictions on the timing of adding lactose, as long as it occurs after the appropriate hydrolysate is generated. For example, in some specific implementations, the entire hydrolysis process (from the start of heating to the start of hydrolysis temperature to the end of heating) can be divided into three equal time periods. Therefore, lactose can be added after the start of the third time period (i.e., the final time period of hydrolysis). In other specific implementations, lactose can also be added 3 to 8 minutes before the end of hydrolysis (when the hydrolysis heating stops), such as 4 minutes, 5 minutes or 6 minutes before the end of hydrolysis.

[0093] After the addition of lactose, optionally, the glycosylation reaction in the mixture can be promoted by auxiliary measures, such as stirring. Furthermore, in some preferred embodiments, the glycosylation reaction takes at least 4 minutes, for example, 4 to 10 minutes.

[0094] Furthermore, there are no particular limitations on the total degree of hydrolysis of whey protein in the hydrolysis process of this invention, which can typically be 8 to 16% (OPA test).

[0095] (Enzyme inactivation)

[0096] After enzymatic hydrolysis, the hydrolysate of whey protein can be subjected to enzyme inactivation treatment.

[0097] This invention has demonstrated that properly adjusting the pH value of the hydrolysate solution can effectively inhibit the thermal denaturation of protein components caused by high-temperature treatment during enzyme inactivation.

[0098] In some specific embodiments, the pH of the hydrolysate solution can be adjusted to 7.2–8.0, preferably 7.5–7.8, before undergoing heat-induced enzyme inactivation. There are no particular limitations on the method for adjusting the pH; for example, various water-soluble alkaline components, such as one or more alkali metal hydroxides, can be used. However, if the pH is too low, it will fail to protect the protein components during enzyme inactivation; if the pH is too high, more alkaline components will need to be introduced, resulting in excessive ash content in the final product.

[0099] There are no particular restrictions on enzyme inactivation treatment. For example, high-temperature inactivation can be used. In some specific embodiments, the enzyme inactivation temperature can be 105-110°C, and the enzyme inactivation time can be no more than 30 seconds, preferably 10-25 seconds.

[0100] (Other steps)

[0101] In addition to the above-mentioned hydrolysis and enzyme inactivation steps, the whey protein hydrolysis method of the present invention may optionally include sterilization, concentration and drying steps.

[0102] The sterilization step can be performed at any desired time after enzyme inactivation. In some preferred embodiments, steam jet sterilization (DSI) can be used, with the sterilization temperature controlled at 75-80°C and the sterilization time at 10-20 seconds.

[0103] For the concentration step, evaporation concentration can be used. In some specific embodiments, a triple-effect evaporator can be used to concentrate the system after enzyme inactivation (and sterilization). Furthermore, the solid content of the concentrated solution system can be 35% by mass or more, preferably 36% to 45% by mass, and more preferably 37% to 42% by mass. Since the glycosylation modification reaction described above leads to an increase in the solubility of the hydrolysate, the solid content of the concentrate of the present invention can be significantly improved compared to conventional methods.

[0104] For the drying step, spray drying is typically used to obtain a solid powdered hydrolyzed whey protein product. There are no particular limitations on the temperature, pressure, and other conditions for spray drying; standard operating procedures in the field can be followed.

[0105] (Whey protein products)

[0106] The whey protein product of the present invention is the hydrolyzed whey protein product described above. Preferably, it can exist in solid (powder) form, or it can be prepared as an aqueous solution for further use.

[0107] In some preferred embodiments, the whey protein product of the present invention has the following molecular weight distribution:

[0108] (i) The content of protein components with a molecular weight of less than 3000 Da in the whey protein product is 75% by mass or more of the total protein, preferably 77% by mass or more, and more preferably 79% by mass or more.

[0109] Optionally, it may also have the following molecular weight distribution:

[0110] (ii) The content of protein components with a molecular weight greater than 3000 Da and less than 10000 Da in whey protein products shall be 3% to 10% by mass.

[0111] Furthermore, the whey protein products of the present invention are particularly suitable for the preparation of infant formula milk products, and their ash content is less than 5.5% by mass.

[0112] In some other specific embodiments, the content of protein components (protein / peptide / amino acid) in the whey protein product of the present invention is 25% by mass or more, preferably 30% by mass or more, and this content is based on the total dry weight of the product.

[0113] (Formulated dairy products)

[0114] Furthermore, the present invention also provides a method for preparing a formula dairy product, wherein the method includes the preparation method of the whey protein product described above, since the whey protein product described above is added or used in the method.

[0115] For this formula dairy product, the following components can be mixed according to the existing technology for preparing formula milk powder:

[0116] Specifically, the components of the formulated dairy product of the present invention may include:

[0117] (A) The whey protein product of the present invention described above, and one or more of the following additional components (i.e., these components are not derived from the whey protein product described above):

[0118] (B) Functional protein components, (C) Carbohydrate components, (D) Fats and oils, (E) Mineral salt components, (F) Vitamin components / probiotic components.

[0119] Functional protein components

[0120] There are no particular restrictions on the functional protein components that can be used. These can include various caseins, immunoglobulins, lactoferrin, and other whey proteins besides those mentioned above. There are no specific restrictions on the amount of these components added, as long as they comply with laws and regulations. These protein components can be derived directly from animal milk, such as (raw) cow's milk, or as purified protein fractions.

[0121] carbohydrate components

[0122] There are no particular restrictions on the type or source of carbohydrates added to the formula dairy products of this invention. Carbohydrates commonly used in formula milk powder products for the elderly in this field can be used.

[0123] In some specific embodiments, the carbohydrate component mentioned in this invention mainly refers to sugars. These sugars are typically a general term for polyhydroxy aldehydes or polyhydroxy ketones and their condensation polymers and certain derivatives, generally composed of carbon, hydrogen, and oxygen. All sugars can be written with the empirical molecular formula: C n (H2O) n .

[0124] In this invention, the carbohydrates typically include monosaccharides, disaccharides, polysaccharides, or oligosaccharides.

[0125] Monosaccharides can mainly include glucose, fructose, etc.

[0126] Disaccharides, polysaccharides, or oligosaccharides can include: sucrose, lactose, fructotriose, fructotetraose, fructopentose, fructooligosaccharides, glucosamine, (maltodextrin), and various forms of human milk oligosaccharides.

[0127] In addition, the carbohydrates can also be added in the form of dietary fiber. Examples of dietary fiber include one or more of the following: inulin, konjac flour, galactooligosaccharides, fructooligosaccharides, isomaltooligosaccharides, soybean polysaccharides, cyclodextrin, resistant dextrin, and soybean fiber.

[0128] Furthermore, there is no particular limitation on the total carbohydrate content in the formula dairy products of the present invention. It can be formulated with reference to the carbohydrate content in formula milk powder products commonly used for specific populations, such as infants and young children.

[0129] Oil components

[0130] There are no particular restrictions on the types of oil components added to the dairy products formulated in this invention; fatty acid glycerides commonly used in the art can be used.

[0131] These glycerides can be obtained from plant extraction or through artificial synthesis (transesterification). Transesterification can be achieved by esterification of glycerol with fatty acids in the presence of a catalyst, or by transesterification of triglycerides and fatty acids from various existing sources in the presence of a (specific) catalyst (enzyme). For plant oils extracted from plants, the desired fatty acid glycerides can be obtained by mixing one or more of the following plant oils: rapeseed oil, soybean oil, sunflower oil, olive oil, sesame oil, corn oil, flaxseed oil, and camellia seed oil.

[0132] The fatty acid glycerides described in this invention are primarily triglycerides. Examples of such glycerides include OPL, OPO, MLCT, OOL, OPP, OLO, OLL, LPL, LPLn, OPLn, LPCa, and OPCa.

[0133] The term "MLCT structured mixed ester" refers to a structurally mixed ester whose main components are medium- to long-chain fatty acid triglycerides. "MLCT" stands for Middle to Long Chain Triglycerides, a structural ester whose glycerol backbone contains both medium-chain fatty acids (M) and long-chain fatty acids (L). Medium-chain fatty acids are those containing 6 to 12 carbon atoms, while long-chain fatty acids are those with more than 12 carbon atoms. MLCTs possess the characteristics of both medium- and long-chain fatty acids, offering the advantages of supplementing essential fatty acids, providing rapid energy, and not causing fat accumulation. Common MLCTs include OPLa, LPLa, OPCa, OLaO, OLaL, OMLa, SLaL, and SLaO.

[0134] Mineral salt components

[0135] The mineral salts that can be added to the dairy products formulated in this invention are mainly used to introduce calcium or other trace nutrients, including iron, copper, manganese, zinc, cobalt, molybdenum, chromium, nickel, vanadium, fluorine, selenium, iodine, silicon, tin, etc.

[0136] Furthermore, regarding the content of mineral salts in formula dairy products, as long as it complies with the provisions of laws and regulations, it is acceptable.

[0137] Other nutritional supplement ingredients

[0138] There are no particular restrictions on other nutritional supplement ingredients that can be added to the dairy products formulated according to the present invention, and they can be prepared in accordance with existing methods in the art.

[0139] In some specific implementations, these supplement ingredients include one or more selected from vitamins and probiotics.

[0140] Examples of vitamins include vitamin A, beta-carotene, vitamin D3, vitamin E, vitamin K1, vitamin B1, vitamin B2, vitamin B6, and vitamin B6. 12 One or more of the following: Vitamin C, pantothenic acid, folic acid, niacin, and biotin.

[0141] For probiotics, for example, Bifidobacteria probiotics that are beneficial to the gut.

[0142] Furthermore, there are no particular restrictions on the source of each of the components (B) to (F) above; for example, they can be introduced by mixing with animal milk or other nutritional additives.

[0143] Furthermore, the above-mentioned formula dairy products of the present invention, through adjustments to their composition, are in principle suitable for various population groups, but in some specific embodiments, they are particularly suitable for formula dairy products for infants and young children.

[0144] Example

[0145] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Raw materials or instruments whose manufacturers are not specified are all commercially available conventional products.

[0146] Example 1

[0147] Hydrolyzed whey protein powder is obtained through the following methods:

[0148] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0149] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6 AU-N / g) and flavor protease (Flavourzyme 500 mg, 500 LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40 min;

[0150] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:0.5, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 7.2 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0151] Step 4: Concentrate the enzyme-inactivating solution by triple-effect evaporation. The preheating temperature is 50℃, the DSI sterilization temperature is 80℃, the time is 15s, the temperature of the first effect is 70℃, the temperature of the second effect is 60℃, the temperature of the third effect is 50℃, and the concentration of the output solution is 35%.

[0152] Step 5: The feed concentration for spray drying is the same as the discharge concentration from the evaporator. The feed preheating temperature is 60℃, the air inlet temperature is 200℃, and the exhaust temperature is 85℃.

[0153] Example 2

[0154] Hydrolyzed whey protein powder is obtained through the following methods:

[0155] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0156] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6AU-N / g) and flavor protease (Flavourzyme 500MG, 500LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40min;

[0157] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:0.5, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 7.5 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0158] Step 4: Concentrate the enzyme-inactivating solution by triple-effect evaporation. The preheating temperature is 50℃, the DSI sterilization temperature is 80℃, the time is 15s, the temperature of the first effect is 70℃, the temperature of the second effect is 60℃, the temperature of the third effect is 50℃, and the concentration of the output solution is 38%.

[0159] Step 5: The feed concentration for spray drying is the same as the discharge concentration from the evaporator. The feed preheating temperature is 60℃, the inlet air temperature is 200℃, and the exhaust air temperature is 88℃.

[0160] Example 3

[0161] Hydrolyzed whey protein powder is obtained through the following methods:

[0162] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0163] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6AU-N / g) and flavor protease (Flavourzyme 500MG, 500LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40min;

[0164] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:0.5, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 8.0 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0165] Step 4: Concentrate the enzyme-inactivating solution by triple-effect evaporation. The preheating temperature is 50℃, the DSI sterilization temperature is 80℃, the time is 15s, the temperature of the first effect is 70℃, the temperature of the second effect is 60℃, the temperature of the third effect is 50℃, and the concentration of the output solution is 38%.

[0166] Step 5: The feed concentration for spray drying is the same as the discharge concentration from the evaporator. The feed preheating temperature is 60℃, the inlet air temperature is 200℃, and the exhaust air temperature is 88℃.

[0167] Example 4

[0168] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0169] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6AU-N / g) and flavor protease (Flavourzyme 500MG, 500LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40min;

[0170] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:0.2, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 7.5 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0171] Step 4: Concentrate the enzyme-inactivating solution by triple-effect evaporation. The preheating temperature is 50℃, the DSI sterilization temperature is 80℃, the time is 15s, the temperature of the first effect is 70℃, the temperature of the second effect is 60℃, the temperature of the third effect is 50℃, and the concentration of the output solution is 35%.

[0172] Step 5: The feed concentration for spray drying is the same as the discharge concentration from the evaporator. The feed preheating temperature is 60℃, the air inlet temperature is 200℃, and the exhaust temperature is 85℃.

[0173] Example 5

[0174] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0175] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6AU-N / g) and flavor protease (Flavourzyme 500MG, 500LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40min;

[0176] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:3, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 7.5 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0177] Step 4: Concentrate the enzyme-inactivating solution by triple-effect evaporation. The preheating temperature is 50℃, the DSI sterilization temperature is 80℃, the time is 10-20s, the temperature of the first effect is 70℃, the temperature of the second effect is 60℃, the temperature of the third effect is 50℃, and the concentration of the output solution is 45%.

[0178] Step 5: The feed concentration for spray drying is the same as the discharge concentration from the evaporator. The feed preheating temperature is 40-70℃, the inlet air temperature is 190℃, and the exhaust air temperature is 90℃.

[0179] Comparative Example 1

[0180] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0181] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6AU-N / g) and flavor protease (Flavourzyme 500MG, 500LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40min;

[0182] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:0.5, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 7.0 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0183] Comparative Example 1 was compared with Example 1. In step 3, the pH of Comparative Example 1 was adjusted to 7.0 after hydrolysis, and enzyme inactivation was performed. After enzyme inactivation, it was found that the protein in Comparative Example 1 was severely denatured. Figure 2 In contrast, the protein in Example 1 did not denature, such as Figure 1 .

[0184] Comparative Example 2

[0185] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0186] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6AU-N / g) and flavor protease (Flavourzyme 500MG, 500LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40min;

[0187] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:0.5, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 8.2 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0188] Step 4: Concentrate the enzyme-inactivating solution by triple-effect evaporation. The preheating temperature is 50℃, the DSI sterilization temperature is 80℃, the time is 15s, the temperature of the first effect is 70℃, the temperature of the second effect is 60℃, the temperature of the third effect is 50℃, and the concentration of the output solution is 40%.

[0189] Step 5: The feed concentration for spray drying is the same as the discharge concentration from the evaporator. The feed preheating temperature is 60℃, the inlet air temperature is 190℃, and the exhaust air temperature is 90℃.

[0190] In Comparative Example 2, when the pH of the solution to be inactivated by enzyme was adjusted to 8.2, although the solution was stable after enzyme inactivation, the amount of KOH added was relatively large. The final product test results showed that the ash content was 6.2%, which exceeded the national standard requirement of ≤5.5%, and therefore could not be used for the production of infant formula.

[0191] Comparative Example 3

[0192] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0193] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6AU-N / g) and flavor protease (Flavourzyme 500MG, 500LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40min;

[0194] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:0.1, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 7.5 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0195] Step 4: Concentrate the enzyme-inactivating solution by triple-effect evaporation. The preheating temperature is 50℃, the DSI sterilization temperature is 80℃, the time is 15s, the temperature of the first effect is 70℃, the temperature of the second effect is 60℃, the temperature of the third effect is 50℃, and the concentration of the output solution is 22%.

[0196] Step 5: The feed concentration for spray drying is the same as the discharge concentration from the evaporator. The feed preheating temperature is 40-70℃, the inlet air temperature is 200℃, and the exhaust air temperature is 80℃.

[0197] In Comparative Example 3, in step 3, lactose was added 5 minutes before the end of hydrolysis, according to the ratio of protein to lactose = 1:0.1. In step 4, the solid content of the concentrate outlet concentration could only reach 22%. If the concentration was increased further, the fluidity of the concentrate would become poor, and it would show a gelation tendency, which would not be conducive to the flow of the concentrate in the evaporator. The spray-dried product obtained in step 5 had fine particles, poor mixing, and a product yield of 71%, which was low.

[0198] Comparative Example 4

[0199] Step 1: Mix concentrated whey protein powder WPC80 with a certain amount of pure water to prepare a protein solution with a mass concentration of 10%. Heat the resulting protein solution to 50±2℃.

[0200] Step 2: Adjust the pH of the protein solution to 7.0±0.2 using KOH solution, add complex protease (Protamex 1.6, 1.6AU-N / g) and flavor protease (Flavourzyme 500MG, 500LAPU / g), the amount added is 2.5% of the substrate protein content, and the ratio of complex protease to flavor protease is 2:3, stir and hydrolyze at 50±2℃ for 40min;

[0201] Step 3: 5 minutes before the end of hydrolysis, add lactose at a ratio of protein to lactose of 1:3.1, continue stirring to dissolve for 5 minutes. After hydrolysis, adjust the pH of the solution to 7.5 with KOH solution and then inactivate the enzyme at 105℃ for 20 seconds.

[0202] Step 4: Concentrate the enzyme-inactivating solution by triple-effect evaporation. The preheating temperature is 50℃, the DSI sterilization temperature is 80℃, the time is 15s, the temperature of the first effect is 70℃, the temperature of the second effect is 60℃, the temperature of the third effect is 50℃, and the concentration of the output solution is 45%.

[0203] Step 5: The feed concentration for spray drying is the same as the discharge concentration from the evaporator. The feed preheating temperature is 40-70℃, the inlet air temperature is 185℃, and the exhaust air temperature is 85℃.

[0204] In Comparative Example 4, the obtained spray-dried product was in good condition, but the protein content of the product was low, with a final product protein content of 23.8%, which is lower than the requirement of ≥25% protein content in GB11674.

[0205] Application Example 1

[0206] In this invention, the whey protein aqueous solution was not pre-denatured. After hydrolysis according to the type and amount of enzyme added, the degree of hydrolysis and molecular weight distribution of the resulting product are shown in Table 1. The high-performance liquid chromatogram of the product prepared in Example 2 of this invention is shown in Table 1. Figure 3 :

[0207] Table 1:

[0208]

[0209] The hydrolysis time of the hydrolysis technology in this invention is 40-60 minutes, which is much shorter than the 2-4 hours of previous inventions, thus improving production efficiency. Moreover, the degree of hydrolysis and molecular weight distribution of the obtained product are also improved to a certain extent compared with commercially available products.

[0210] Application Example 2

[0211] The hydrolyzed whey protein powder prepared in this invention was mixed with conventional commercially available hydrolyzed whey protein powder to form a 10% (w / w) solution, and sensory comparison was performed. Sensory evaluation method:

[0212] (1) Bitterness evaluation: 10g of each of the three partially hydrolyzed whey protein powders (two commercially available products and self-produced Example 2) were weighed and dissolved in 90mL of warm water at about 50℃. The mixture was stirred thoroughly to dissolve the bitterness. Mouthwash at the same temperature was provided and 10 professional sensory evaluators were asked to conduct comparative evaluation.

[0213] (2) Wetness evaluation: 1g of each of the three partially hydrolyzed whey protein powders (two commercially available products and self-produced Example 2) was weighed out, and 50°C distilled water was measured into a 500mL beaker. The weighed milk powder was poured into the beaker, and a stopwatch was started at the same time. The time was stopped when all the products were submerged in water, and the time taken was recorded.

[0214] (3) White Spot Evaluation: 10g of each of the three partially hydrolyzed whey protein powders (two commercially available products and one self-produced product, Example 2) were weighed out and dissolved in 90mL of approximately 50℃ warm water. The solutions were stirred until fully dissolved. After the solutions were poured into beakers and allowed to stand for 1 minute, 3 / 4 of a clean microbial slide was immersed in the solution and vigorously stirred back and forth for 5 seconds (do not stir in a circular motion). The slides were then removed vertically, tilted at approximately 60° for 10 seconds, and the back and bottom of the slides were wiped dry. The slides were then compared against a well-lit black background.

[0215] (4) Solubility evaluation: After completing the white spot evaluation, let the remaining reconstituted solution stand for 30 minutes and observe the state of the solution.

[0216] The sensory evaluation results are shown in Table 2 below:

[0217] index Commercially available product 1 Commercially available product 2 This invention bitterness Bitterness is average It has a strong bitter taste Mildly bitter wettable Dissolution time is relatively long Dissolution time is relatively long It dissolves relatively easily color White White White White spots Many white spots Many white spots White spots are generally Solubility After standing, the layers are relatively distinct. After standing, the layers are clearly visible. No separation after standing

[0218] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0219] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing a whey protein product, characterized in that, The method includes: The steps of hydrolysis and enzyme inactivation, in, In the hydrolysis step, the whey protein aqueous solution is hydrolyzed in the presence of an enzyme. The hydrolysis temperature is below 55°C, the hydrolysis time is 30–60 min, and the pH of the hydrolysis system is 6.8–7.

2. Furthermore, the whey protein aqueous solution undergoes a thermal process at a temperature of 20–35°C before hydrolysis. Lactose is added to the system containing hydrolyzed whey protein components 4-8 minutes before the end of hydrolysis, and the amount of lactose added is 15%-300% by mass of the whey protein content. In the enzyme inactivation step, after the hydrolysis is completed, the pH of the hydrolysate solution is adjusted to 7.5-8.0 before heating to inactivate the enzyme. The enzyme is a combination of a complex protease and a flavor protease, and the mass ratio of the complex protease to the flavor protease is 1.5-2.5:2.5-3.

5.

2. The method according to claim 1, characterized in that, In the hydrolysis step, the solid content of the whey protein aqueous solution is less than 18% by mass; and the carbohydrate content of the whey protein aqueous solution, based on the dry weight of solids, is less than 10% by mass.

3. The method according to claim 1 or 2, characterized in that, In the enzyme inactivation step, the temperature for heating the enzyme is 105-110℃ and the time is less than 30 seconds.

4. The method according to claim 1 or 2, characterized in that, The method further includes a concentration step after the enzyme inactivation step.

5. The method according to claim 4, characterized in that, In the concentration step, the hydrolysate solution after enzyme inactivation is concentrated to a solid content of 35% by mass or more.

6. The method according to claim 1 or 2, characterized in that, The whey protein product obtained by the method contains more than 75% of the total protein, of which the molecular weight is below 3000 Da.

7. A method for preparing infant formula milk powder, characterized in that, The method includes the method for preparing whey protein products according to any one of 1 to 6.

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