Preparation method of hydrolyzed whey protein and food

Abstract

The invention belongs to the field of food, and relates to a preparation method of hydrolyzed whey protein and food, the method comprises the following steps: a dissolving step: dissolving a whey protein raw material in water to obtain an aqueous solution with the solid content of 7-13% by mass and the pH value of 6.5-7.5; a hydrolysis step: hydrolyzing the whey protein aqueous solution in the presence of a compound enzyme, wherein the hydrolysis temperature is 50-60 DEG C; a concentration step: concentrating the hydrolyzed solution system until the solid content is 30-45% by mass; wherein the ash content in the whey protein raw material is 4% by mass or less. The method is simple in process and high in applicability, the production efficiency is greatly improved, the high-quality hydrolyzed whey protein product can be obtained, and the product is particularly suitable for preparing infant formula food.

Description

Technical Field

[0001] The invention belongs to the field of food, and relates to a preparation method of hydrolyzed whey protein and food, in particular to a preparation method of hydrolyzed whey protein which is suitable for infants with high risk of milk protein allergy and can provide appropriate osmotic pressure at the same time. Background Art

[0002] Whey protein is a high-quality protein source, rich in essential amino acids, especially branched-chain amino acids, which can participate in biological processes such as protein synthesis, cell repair, and growth and development in the body, and plays an important role in promoting muscle growth, recovery and repair. However, studies have shown that among 818 underage patients suspected of food allergies who visited the outpatient department of the allergy department of a certain hospital from June 2018 to November 2020, the milk sensitization rate was 25.7%, especially the milk sensitization rate of infants and young children aged 0 to 3 years was 39.2%. Cow's milk contains more than 20 kinds of proteins, all of which are potentially allergenic, but it is generally believed that β-lactoglobulin in whey protein is the main allergen, followed by α-lactalbumin. Therefore, reducing the allergenicity of whey protein is of great significance for nutritional supplementation for people allergic to cow's milk protein.

[0003] Protein digestion takes place in the stomach and small intestine. Gastric acid and pepsin will initially decompose the protein, which is then decomposed into amino acids and some short peptides by trypsin and chymotrypsin in the small intestine. Hydrolyzed whey protein is whey protein that has been hydrolyzed into short peptide chains and amino acids with smaller molecular weight during processing, which is equivalent to decomposing protein in advance. Therefore, the absorption rate of hydrolyzed whey protein is faster than that of ordinary whey protein, and it is easier to digest and absorb.

[0004] Especially for people with changed intestinal function, their ability to digest and absorb protein decreases, and they cannot completely digest the whole protein. Although amino acid products have a smaller molecular weight, their osmotic pressure is higher and can easily cause diarrhea. Compared with whole protein, hydrolyzed whey protein is a pre-digested protein that does not require complete digestive tract function. Even people with gastrointestinal dysfunction can digest and absorb it well, and quickly supplement amino acids for the human body. Compared with amino acids, hydrolyzed whey protein has a lower osmotic pressure, can reduce gastrointestinal adverse reactions, and is more tolerable. Therefore, it is widely used in the nutritional supply of people with gastrointestinal dysfunction.

[0005] Based on the good physiological functions and nutritional value of hydrolyzed whey protein, there are currently public studies on the preparation process of hydrolyzed whey protein, such as:

[0006] Reference 1 discloses a food-grade hydrolyzed whey protein and a preparation method thereof, which uses whey protein and its products as raw materials, uses a high-pressure reactor as a hydrolysis device, and the process includes high-concentration hydrochloric acid hydrolysis, evaporation deacidification, activated carbon decolorization, anion exchange resin purification, and freeze drying. However, this method uses acid hydrolysis to oxidize Cys and Met, partially destroy Ser and Thr, and convert Gln and Asn into Glu and Asp, thereby reducing the quality and biological value of the protein. At the same time, there are problems such as low production efficiency, difficulty in controlling ash, chlorate and perchlorate.

[0007] Reference 2 discloses a partially hydrolyzed whey protein powder and a preparation method thereof, wherein concentrated whey protein is prepared into a whey protein aqueous solution, and heat-treated to denature the protein, followed by adding a composite protease at a suitable temperature for hydrolysis, terminating the enzymatic hydrolysis and concentrating by nanofiltration, and then spray drying to obtain a finished product. Although this method uses membrane filtration concentration to avoid the problem of high protein concentration, the membrane filtration concentration process is costly and the concentration increase is limited (25-35%). The electrophoresis bands of the finished product show that β-lactoglobulin still has a certain content, and the allergenicity is relatively high.

[0008] Reference 3 discloses a whey protein hydrolysate rich in arginine and a preparation method thereof, wherein the method heat-treats the whey protein aqueous solution to denature the protein, first adds papain to hydrolyze until the degree of hydrolysis reaches 35-45%, then adds aminopeptidase to hydrolyze until the degree of hydrolysis reaches 55-65%, and terminates the hydrolysis; the solution after the hydrolysis is terminated is ultrafiltered through an ultrafiltration membrane, concentrated, and a whey protein hydrolysate rich in arginine is obtained. The method adopts membrane concentration and freeze-drying technology, which not only has high equipment cost and complex process, but also has long freeze-dried powder time and low production efficiency, and the essential amino acid components in the obtained hydrolyzate are seriously lost. In addition, the method is to prepare a hydrolyzate with high arginine content, which focuses more on the functionality of the product with high arginine content, and is not suitable for the hydrolysis of whey protein powder in the full amino acid mode.

[0009] Reference 4 discloses a method for preparing a debittered hydrolyzed whey protein rich in small molecule polypeptides, wherein alkaline protease or neutral protease is added for primary protease hydrolysis, debittering aminopeptidase or flavor exoprotease is added for secondary protease hydrolysis, and then three-stage ultrafiltration and three-stage nanofiltration are performed, and spray drying is performed to obtain a debittered hydrolyzed whey protein rich in small molecule polypeptides. The hydrolyzed whey liquid treated by the membrane process has a high amino acid removal rate, and many amino acids are essential amino acids. The treatment method reduces the nutritional value of whey protein. At the same time, the low-concentration ultrafiltrate is not concentrated and directly spray-dried, which consumes a lot of energy during the period, and the product has fine particle size and poor solubility. At the same time, the method does not detect the allergenic fragments of the hydrolyzed whey protein, and its allergenicity is unknown.

[0010] Reference 5 discloses a method for reducing β-lactoglobulin in concentrated whey protein powder by using a biocomposite enzyme hydrolysis, wherein the concentrated whey protein powder is prepared into a solution of a certain concentration, and after adding a composite enzyme, the solution is hydrolyzed for 3 to 8 hours, and then the solution is prepared by processes such as enzyme inactivation, concentration, and spray drying. This method has a long hydrolysis time and high energy consumption, and the maximum concentration of the concentrated solution is 35%. The powder produced by spray drying has fine particles and poor solubility. At the same time, this method does not detect the β-lactoglobulin and allergenic fragments after hydrolysis, and its allergenicity is unknown.

[0011] Reference 6 discloses a hydrolyzed whey protein modified complex and a preparation method thereof, wherein a protease and a carbohydrate compound are added to a whey protein solution of a certain concentration, hydrolyzed under certain conditions, and the solution is freeze-dried to obtain a lyophilized powder; the obtained lyophilized powder is reacted at 55-65°C and a relative humidity of 79-82% for 8-10 hours to obtain a hydrolyzed whey protein modified complex. This method requires the addition of additional carbohydrate compounds, which may result in a problem of reduced protein content in the final product.

[0012] Cited document 7 discloses a high-glutamine content hydrolyzed whey protein powder with improved digestibility and a preparation method thereof. The method uses whey protein isolate as a raw material, pre-treats it under high pressure, and adds protease to hydrolyze it. The primary enzymatic hydrolyzate is cross-linked by glutamine transaminase (TG enzyme), filtered by ultrafiltration to enrich the protein with high glutamine content, and then subjected to secondary enzymatic hydrolysis by composite protease, and spray-dried to obtain the high-glutamine content hydrolyzed whey protein powder with improved digestibility.

[0013] Reference 8 discloses a low-allergenic whey protein powder based on two-step enzymatic hydrolysis and enzyme membrane reaction and a preparation method thereof. The method uses whey as a substrate, utilizes a two-step proteolysis technique to hydrolyze the allergenic sites in whey protein, and utilizes the selective permeation of the membrane to separate and obtain a protein hydrolyzate with a molecular weight below 1kDa and no allergenic sites. The method is characterized in that the antigenic activity of the raw whey protein isolate is reduced by more than 80% to a modified product. However, this method removes peptides greater than 1kDa by membrane filtration, resulting in a decrease in the nutritional value of whey protein, an 80% decrease in antigenic activity, and a 20% allergy risk. In addition, nanofiltration concentration is used, and the production cost is high. Removing 1kDa peptides by membrane filtration will increase the proportion of amino acids in the final product and increase the osmotic pressure.

[0014] Reference 9 discloses a low-sensitivity whey protein hydrolysate and a preparation method thereof, wherein concentrated whey protein is dissolved in water, then denatured at high temperature, then hydrolyzed using a composite protease composed of alkaline protease, papain and flavor protease, and then the whey protein hydrolysate is desalted and dried to obtain the whey protein hydrolysate. The inhibition rate of β-lactoglobulin in the whey protein hydrolysate prepared by this method can reach 84%, and electrophoresis detection shows that there is still intact β-lactoglobulin, which has high allergenicity. At the same time, the whey protein hydrolysate needs to be desalted by anion and cation exchange resin (according to the detailed rules for the review of infant formula food production license, whey powder with an ash content greater than 5.5% cannot be used in the production of infant formula food). The process is complicated, and the method does not provide a detailed description of the drying and powdering process. The whole process is only in the laboratory pilot stage and has not been industrialized.

[0015] Therefore, it is necessary to provide a method for preparing hydrolyzed whey protein with the advantages of simple process steps, high protein content, low ash content, low allergenicity, and high nutrient retention rate, so as to provide a guarantee for the industrial and large-scale production of hydrolyzed whey protein.

[0016] References:

[0017] Reference 1: CN108752462A

[0018] Reference 2: CN107136295A

[0019] Reference 3: CN103014111A

[0020] Reference 4: CN112662723A

[0021] Reference 5: CN102940126A

[0022] Reference 6: CN117617344A

[0023] Reference 7: CN114540449A

[0024] Reference 8: CN105248836A

[0025] Reference 9: CN101297674B Summary of the invention

[0026] Problem that the invention aims to solve

[0027] As mentioned above, whey protein has the characteristics of high nutritional value and amino acid composition that meets the amino acid requirements of the human body. However, intact proteins such as β-lactoglobulin in whey protein are a common allergen for infants and young children. In order to reduce the risk of allergic reactions to milk protein in infants at high risk of allergies, hydrolyzed whey protein formula can be used to replace intact protein formula products. However, the products prepared by the preparation methods of the prior art (such as Reference 2, Reference 8 and Reference 9) still contain a certain amount of intact proteins such as β-lactoglobulin, which poses a certain degree of allergenicity risk.

[0028] In theory, deep hydrolysis formula products can better eliminate allergenicity, but in actual production, excessive hydrolysis leads to increased production costs and worse taste. In addition, after enzymatic hydrolysis, the protein is converted from a larger molecule into multiple peptides and amino acids with smaller molecular weights. The total number of solute particles in the solution of the same mass concentration increases, and the osmotic pressure of the solution increases. Therefore, the osmotic pressure of the hydrolyzed protein solution of equal mass concentration is higher than that of the whole protein solution (for example, cited document 8). In addition, the processing of infant formula food also requires the addition of a variety of ingredients, including minerals, lactose and other raw materials that have a greater impact on osmotic pressure. Under similar conditions of lactose, ash and protein content, the osmotic pressure of the hydrolyzed protein infant formula of equal concentration is greater than that of the ordinary whole protein infant formula, which further puts forward requirements for the osmotic pressure of hydrolyzed whey protein.

[0029] Furthermore, from the perspective of retaining the nutritional value of the product, some methods use chemical methods and ion exchange methods, but the process is not only relatively complicated, but also causes loss of product quality and nutritional value (for example, cited document 1); in addition, in order to obtain a good subsequent processing type (spray drying or freeze drying, etc.) or to retain components in a characteristic molecular weight range during preparation, specific membrane concentration processing is used, but this also substantially causes the loss of some amino acid components, reducing the overall nutritional value of the final product (for example, cited document 3, cited document 4, etc.).

[0030] In view of this, the present invention provides a method for preparing hydrolyzed whey protein which is particularly suitable for infant formula powder or infant formula milk and has high protein, high retention rate of various amino acid components, low ash content, low osmotic pressure and low allergenicity.

[0031] The present invention uses whey protein with an ash content of less than 4% by mass as a raw material, and by adjusting the concentration of the whey protein raw material and the enzymatic conditions, not only can the hydrolyzed protein of suitable molecular weight be obtained, but also the excessive increase in osmotic pressure caused by excessive hydrolysis can be avoided, and the problems of undesirable bitterness and other mouthfeel caused by protein degradation can be avoided. That is, the present invention is limited to specific dissolution and hydrolysis steps, while retaining the hydrolyzed whey protein nutrients to the maximum extent, it also meets the needs of high protein, low ash, low osmotic pressure, low sensitization, and good solubility, and then obtains a preparation method of hydrolyzed whey protein with simple process operation, short production cycle, low energy consumption, high efficiency, and strong process applicability.

[0032] Solutions for solving problems

[0033] The present invention believes that the above technical problems can be solved by implementing the following technical solutions:

[0034] [1]. The present invention provides a method for preparing hydrolyzed whey protein, comprising the following steps:

[0035] Dissolving step: dissolving the whey protein raw material in water to obtain an aqueous solution with a solid content of 7 to 13% by mass and a pH value of 6.5 to 7.5;

[0036] The hydrolysis step is as follows: hydrolyzing the whey protein aqueous solution in the presence of a complex enzyme, wherein the hydrolysis temperature is 50-60° C.;

[0037] Concentration step: concentrating the hydrolyzed solution system to a solid content of 30-45% by mass;

[0038] The ash content in the whey protein raw material is 4% by mass or less.

[0039] [2] The preparation method according to [1], wherein in the dissolving step, the dissolving temperature is 50-60°C.

[0040] [3] The preparation method according to [1] or [2], wherein in the dissolving step, an alkaline substance is added to adjust the pH value of the aqueous solution.

[0041] [4] The preparation method according to any one of [1] to [3], wherein in the hydrolysis step, the composite enzyme is a combination of an endoprotease and an exoprotease; and the amount of the composite enzyme used is 1 to 3% by mass of the protein in the system.

[0042] [5] The preparation method according to [4], wherein in the hydrolysis step, the endoprotease comprises a serine endoprotease; and the exoprotease comprises an aminopeptidase.

[0043] [6] The preparation method according to any one of [1] to [5], wherein in the hydrolysis step, the hydrolysis time does not exceed 100 min.

[0044] [7] The preparation method according to any one of [1] to [6], wherein the method further comprises an enzyme inactivation step after the hydrolysis step and before the concentration step.

[0045] [8] The preparation method according to any one of [1] to [7], wherein the concentration step is carried out by triple-effect falling film evaporation.

[0046] [9] The method according to any one of [1] to [8], wherein the content of protein components with a molecular weight greater than 10,000 Da in the obtained hydrolyzed whey protein is 7.5% by mass or less;

[0047] The content is based on dry weight.

[0048]

[10] The preparation method according to any one of [1] to [9], wherein the degree of hydrolysis of the obtained hydrolyzed whey protein is 22% to 32%.

[0049]

[11] . The preparation method according to any one of [1] to

[10] , wherein the hydrolyzed whey protein is prepared into a 12.5% ​​by mass concentration liquid, and its osmotic pressure at room temperature is less than 300 mOsm / kg H2O.

[0050]

[12] . The present invention also provides a food comprising or using the hydrolyzed whey protein prepared by the preparation method according to any one of [1] to

[11] .

[0051] Effects of the Invention

[0052] By implementing the above technical solution, the present invention can achieve the following technical effects:

[0053] 1) The method of the present invention can obtain hydrolyzed whey protein with a suitable degree of hydrolysis and molecular weight by controlling the conditions of the specific dissolution step and the (enzyme) hydrolysis step, and can not only avoid the generation of bad flavors, but also inhibit the excessive increase of the osmotic pressure of the final product. Moreover, by controlling the above conditions, in the subsequent concentration treatment before spraying, not only can the loss of nutrients be avoided, but also a concentrated solution with a higher solid content can be obtained. Moreover, the concentrated solution is suitable for spraying treatment, and the obtained spray-dried product has good dissolvability (solubility).

[0054] 2) The present invention does not require preheating and modification of the whey protein raw material or whey protein solution before hydrolysis, which can further alleviate the impact of thermal denaturation on whey protein hydrolysis and the quality of the final product; and does not require the addition of additional carbohydrate compounds (e.g., lactose) during the preparation process to control the ash content of the final product, which can further avoid the problem of reduced protein content in the final product due to the addition of carbohydrate compounds.

[0055] 3) The method of the present invention has simple process and high applicability, which not only greatly improves the production efficiency, but also can obtain high-quality hydrolyzed whey protein products (wherein the protein content is higher than 70%, the ash content is lower than 5.5%, there is no complete α-lactalbumin and β-lactoglobulin, the allergenic fragments are reduced by 99%, and the osmotic pressure is similar to that of breast milk), which is particularly suitable for preparing infant formula. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 : Flow chart of the preparation process of the present invention;

[0057] Figure 2 : Chromatogram of α-lactalbumin and β-lactoglobulin detection in WPC80 raw material;

[0058] Figure 3 : Chromatogram of detection of α-lactalbumin and β-lactoglobulin in the product prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0059] Various exemplary embodiments, features and aspects of the present invention will be described in detail below. In order to better illustrate the present invention, numerous specific details are provided in the following specific embodiments. It should be understood by those skilled in the art that the present invention can be implemented without certain specific details.

[0060] Unless otherwise stated, the units used in this specification are all international standard units, and the numerical values ​​and numerical ranges appearing in the present invention should be understood to include the inevitable systematic errors in industrial production.

[0061] In this specification, the word "may" means both performing a certain process and not performing a certain process.

[0062] In this specification, the numerical range expressed using "a numerical value A to a numerical value B" means a range including the endpoint numerical values ​​A and B.

[0063] In the present invention, a numerical range expressed using "above" or "below" means a numerical range including the number.

[0064] In the present invention, the use of "optional" or "optionally" indicates that certain substances, components, execution steps, applied conditions and other factors are used or not used.

[0065] In the present invention, "Da" is used to represent the unit of molecular weight "Dalton", that is, "Dalton".

[0066] In the present invention, unless otherwise specified, the "normal temperature" used generally refers to a temperature of 23±2°C.

[0067] In the present invention, unless otherwise stated, "%" used herein means weight or mass percentage.

[0068] In this specification, "infants" are used to refer to a human group under the age of 3 years old.

[0069] In this specification, "ash" and "salt" have the same meaning, which refers to a series of physical and chemical changes that occur in food when burned at high temperatures, with the organic components eventually volatilizing and dissipating, while the inorganic components (mainly inorganic salts and oxides) remain. These residues are called ash, which include soluble ash and insoluble ash.

[0070] In this specification, the term "about" or "substantially" or "essentially" may mean that a value includes the standard deviation of the error of the device or method used to determine the value. The numerical ranges and parameters used to define the present invention are all approximate values, and the relevant numerical values ​​in the specific embodiments have been presented as accurately as possible. However, any numerical value essentially inevitably contains the standard deviation caused by the aforementioned test device or method. Therefore, unless otherwise clearly stated, it should be understood that all ranges, quantities, values ​​and percentages used in the present invention are modified by "about". Here, "about" generally means that the standard deviation of the actual value and the theoretical model or theoretical data is within 3%, preferably 2%, and more preferably 1%.

[0071] In the present invention, the references to "some specific / preferred embodiments", "other specific / preferred embodiments", "embodiments", etc., mean that the specific elements (e.g., features, structures, properties and / or characteristics) described in connection with the embodiments are included in at least one embodiment described herein, and may or may not exist in other embodiments. In addition, it should be understood that the elements may be combined in various embodiments in any suitable manner.

[0072] The primary purpose of the present invention is to provide a method for preparing hydrolyzed whey protein, which comprises dissolving the raw materials and hydrolyzing them in the presence of an enzyme under specific conditions, and then inactivating the enzyme after the hydrolysis reaction, followed by concentration and spray drying to obtain hydrolyzed whey protein solid powder.

[0073] The present invention is mainly based on the following insights:

[0074] The present invention believes that when preparing hydrolyzed whey protein by hydrolysis in the presence of enzymes, it is necessary to take into account the degree of hydrolysis, the retention of nutrients, the optimization of product taste and the osmotic pressure caused by the hydrolyzed product. In addition, in actual industrial large-scale production, the convenience of the drying process and the reconstitution of the final product should also be taken into account.

[0075] The present invention finds that the above-mentioned problems can be taken into account by controlling the optimized conditions, that is, a suitable enzymatic hydrolysis environment is obtained by a specific dissolution step, and further, the temperature of the enzymatic hydrolysis is controlled to obtain a hydrolyzed protein system with a suitable molecular weight. The system not only has a reduced loss of nutritional components after concentration, but also has characteristics suitable for a spray-drying process, so that the obtained spray-dried product has good dissolution properties and also has suppressed osmotic pressure after dissolution.

[0076] First aspect

[0077] The first aspect of the present invention provides a method for preparing hydrolyzed whey protein. Specifically, the method for preparing hydrolyzed whey protein of the present invention mainly includes a dissolution step, a hydrolysis step in the presence of an enzyme, etc., and may also have other optional processing steps if necessary.

[0078] (Whey protein raw material)

[0079] In principle, there is no particular limitation on the source of whey protein in the present invention. For example, the whey protein may be derived from various animal milks, such as cow's milk, goat's milk, horse's milk, camel's milk, etc. Preferably, the whey protein may be derived from cow's milk.

[0080] There is no particular limitation on the method for separating or purifying whey from the animal milk. In some specific embodiments, the separation or purification means includes a defatting process to separate the fat component from the animal milk raw material. In principle, there is no particular limitation on the defatting method, which can be performed by centrifugation or the like. By the defatting process, 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.

[0081] In some specific embodiments, the above separation or purification also includes separating proteins from the raw milk (which has been defatted). The separation of proteins is mainly to separate casein. There is no particular limitation on the method of separating casein. For example, the pH of the raw milk can be adjusted by adding acidic substances to cause casein to coagulate and precipitate near its isoelectric point, thereby separating (acid whey); or, by optionally adding coagulants, fermentation agents and other ingredients to the raw milk, the whey component (sweet whey) is separated while the cheese is formed. In addition, it is also possible to use membrane filtration to intercept and separate protein components of different molecular weights through the use of a filter membrane with a suitable pore size, thereby obtaining a component containing whey protein.

[0082] In some specific embodiments, the above separation or purification also includes desalting and optional concentration steps. Preferably, after defatting and protein separation, the components enriched with whey protein can be desalted and optionally concentrated. There are no special restrictions on the desalting treatment in principle, for example, it can be carried out by membrane filtration (nanofiltration (NF) and / or electrodialysis). In some preferred embodiments, by desalting treatment, more than 80% by mass of inorganic salts, preferably more than 90% by mass, and more preferably more than 95% by mass of inorganic salts can be removed. For the concentration step, it can be carried out at the same time or after desalting, and typically ultrafiltration, diafiltration or reverse osmosis can be used to obtain, for example, a whey protein raw material with a higher protein content.

[0083] The whey protein-containing components obtained by the above-mentioned possible various process treatments can be further dried to obtain whey protein solids. Typically, solid whey protein powder can be obtained by spray drying or the like.

[0084] In addition, the whey protein raw material of the present invention can be prepared by the above method or purchased through commercial channels, such as various commercially available concentrated whey protein powders, isolated whey protein powders, whey protein liquids and other high whey protein content raw materials. Preferably, the whey protein raw material of the present invention can use concentrated whey protein powder.

[0085] There is no particular limitation on the content of whey protein in the whey protein raw material of the present invention, which is related to the preparation method of the whey protein raw material. In some specific embodiments, the whey protein content in the whey protein raw material (based on the total dry weight of the whey protein raw material) can be 50% by weight or more, preferably 60-95% by weight, for example, 65-90% by weight, 70-85% by weight, etc.

[0086] Furthermore, in addition to whey protein, the whey protein raw material of the present invention may optionally contain one or more of carbohydrates, oil components, and inorganic salts. Carbohydrates may include polysaccharides, such as lactose or dietary fiber. In some specific embodiments, based on different purification methods of whey protein, the (dry) content of the carbohydrates is less than 10% by mass, preferably less than 8% by mass, for example, 1-7% by mass, 2-6% by mass, etc., based on the total dry weight of the whey protein raw material.

[0087] In some other preferred embodiments, the lactose in the whey protein can be controlled to be in a lower content range, which can be achieved by the above separation and purification. Based on the total dry weight of the whey protein raw material, the lactose (dry) content is less than 8% by mass, preferably less than 5% by mass, for example, 1-4% by mass, 2-3% by mass, etc.

[0088] In some preferred embodiments, the inorganic salt in the whey protein can be controlled within a relatively low content range, which can be achieved by the above-mentioned separation and purification. Based on the total dry weight of the whey protein raw material, the inorganic salt (dry) content is preferably 4% by mass or less, for example, 1-4% by mass, 2-3% by mass, etc. By controlling the content of the inorganic salt, the whey protein raw material of the present invention can have an ash content of 4% by mass or less, preferably 3% by mass or less, and more preferably 2% by mass or less.

[0089] By controlling the ash content of the raw materials, the final hydrolyzed whey protein obtained has a lower ash content and is particularly suitable for the preparation of infant formula food.

[0090] In addition, the whey protein raw material of the present invention may be a whole protein raw material that has not been subjected to any degradation treatment, or a whey protein raw material that has been subjected to a partial degradation treatment but can still be further degraded as described below to reach the desired composition of the present invention.

[0091] Dissolution steps

[0092] Further, after obtaining the above whey protein raw material, it can be mixed with water to form a whey protein aqueous solution before the hydrolysis described below. It has been found that by optimizing the conditions in the dissolution step, a suitable hydrolysis / enzymolysis environment can be obtained.

[0093] In the embodiment of the present invention, the solid content of the whey protein aqueous solution is important, which can be controlled to be 7-13% by mass, preferably 8-12% by mass, and more preferably 9-11% by mass. The present invention believes that too high a solid content means too much enzyme addition or too long a hydrolysis time, and too high a concentration of enzyme inactivation is likely to cause protein denaturation; too low a solid content will lead to insufficient efficiency of the production process, and, subsequently, under the addition of conventional enzymes, it may lead to too high a small molecule protein component, which is not conducive to the control of the taste and osmotic pressure of the final product.

[0094] Further, for the whey protein obtained in the dissolution step, pH control is also important. The present invention finds that by controlling the pH value between 6.5 and 7.5, it is beneficial to obtain a protein of suitable molecular weight for subsequent hydrolysis / enzymatic hydrolysis. In some preferred embodiments of the present invention, the pH value can be controlled between 6.7 and 7.3, more preferably about 7.

[0095] In principle, there is no particular restriction on the method for obtaining the above pH environment. For example, alkaline substances available in the food industry can be added to the protein system. Such alkaline substances include one or more of sodium bicarbonate, sodium citrate, potassium carbonate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, potassium hydroxide, sodium hydroxide, etc. Considering the osmotic pressure, potassium hydroxide can be used. There is no particular restriction on the use of the above alkaline substances. For example, they can be used in the form of aqueous solution.

[0096] In principle, there is no particular restriction on the operating temperature in the dissolution step. From the perspective of facilitating subsequent hydrolysis / enzymatic hydrolysis, the temperature can be controlled between 50 and 60°C. From the perspective of avoiding thermal denaturation, the hydrolysis step described below can be performed immediately after the temperature is raised to this temperature.

[0097] Hydrolysis steps

[0098] The hydrolysis of whey protein of the present invention is performed in the presence of a composite enzyme. In some specific embodiments, the enzyme-containing preparation is added to the protein system obtained in the above dissolution step.

[0099] The composite enzyme that can be used in the present invention can include endoproteases and exoproteases. In some specific embodiments, the endoproteases can be one or more of alkaline proteases, trypsin, pepsin, acidic proteases and neutral proteases; the exoproteases can be one or more of protein deamidase and flavor proteases. In some preferred embodiments, from the perspective of hydrolysis efficiency and inhibition of bad flavor and taste, and mitigation of the effect of enzyme inactivation high temperature treatment on protein components, the enzyme used in the hydrolysis step of the present invention can be a combination of alkaline proteases and flavor proteases in a certain ratio, and it has been found that such a combination of enzymes not only takes into account the above-mentioned hydrolysis efficiency, but also takes into account the above-mentioned flavor and taste, and can also easily obtain the degradation product (protein component) of the desired molecular weight of the present invention. More preferably, the ratio of the alkaline protease to the flavor protease can be 1:1~3, for example, it can be 2:3, 1:2, 2:5, 3:7, 1:3, etc. In addition, the specific endoproteases that can be listed can include serine endoproteases; the exoproteases include aminopeptidases.

[0100] Further, the total amount of the above enzymes is not particularly limited in principle, and can be determined according to the conventional amount corresponding to the characteristics of each enzyme in the art. In some preferred embodiments, the total amount of the enzymes can be used according to 1-3% by mass of the whey protein mass (dry weight), for example, 1.5-2.5% by mass, etc.

[0101] Further, the hydrolysis temperature of the present invention can be maintained between 50 and 60°C, preferably between 52 and 57°C, such as 53°C, 54°C, 55°C, 56°C, etc. It has been found that at this temperature, the above-mentioned complex enzyme can be more appropriately subjected to enzymolysis reaction in the protein solution system, thereby obtaining a protein system with a suitable molecular weight. On the one hand, within this temperature range, the complex enzyme has suitable activity, and on the other hand, the low molecular weight substances generated by enzymolysis do not excessively increase the osmotic pressure.

[0102] The hydrolysis time may be within 100 minutes, preferably 85 to 95 minutes, in some specific embodiments. Within this time, the complex enzyme may decompose the whey protein into hydrolyzed protein components of suitable molecular weight.

[0103] Steps to inactivate enzymes

[0104] After the hydrolysis step, the whey protein may be inactivated to terminate the hydrolysis reaction and obtain a hydrolyzed whey protein solution.

[0105] Specifically, in the enzyme inactivation step, there is no special requirement for the enzyme inactivation temperature and time in principle, and it can be performed with reference to the characteristics of the enzyme in the art. In some specific embodiments of the present invention, the enzyme inactivation temperature can be 90-120°C, preferably 105-110°C, and the enzyme inactivation time can be 10-60s, preferably 15-30s.

[0106] Other Steps

[0107] The method for preparing hydrolyzed whey protein of the present invention may optionally include a concentration step and a drying step in addition to the above-mentioned dissolution step, hydrolysis step and enzyme inactivation step.

[0108] For the concentration step, an evaporation concentration method can be used. In some specific embodiments, a triple-effect evaporator can be used to concentrate the system after the enzyme is inactivated. In addition, for the solution system obtained after concentration, its solid content can be more than 30% by mass, preferably 30% to 45% by mass. Therefore, compared with the previous method, the solid content of the concentrate of the present invention can be significantly improved, which is mainly due to the characteristics of the protein hydrolyzate in the system obtained in the hydrolysis step of the present invention.

[0109] For the drying step, spray drying can be typically used to obtain a solid powdered whey protein hydrolyzate. There is no particular restriction on the temperature, pressure and other conditions of spray drying, and the conventional operating specifications in the art can be referred to.

[0110] Second aspect

[0111] In the second aspect of the present invention, there is provided a hydrolyzed whey protein prepared according to the preparation method described in the first aspect of the present invention. Preferably, the hydrolyzed whey protein may be in the form of a hydrolyzed whey protein powder, or may be prepared into an aqueous solution for further use.

[0112] For the hydrolyzed whey protein of the present invention, in some preferred embodiments, the content of protein components with a molecular weight greater than 10,000 Da in the hydrolyzed whey protein is less than 7.5% by mass of the total protein, preferably less than 7% by mass, for example, it can be 6.5% by mass, 6% by mass, 5.5% by mass, 5% by mass, 4.5% by mass, 4% by mass, etc., and the content is based on dry weight.

[0113] Furthermore, the content of protein components (protein / peptide / amino acid) in the hydrolyzed whey protein of the present invention is 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. This content is based on the total dry weight of the hydrolyzed whey protein.

[0114] In addition, there is no particular limitation on the total hydrolysis degree of the hydrolyzed whey protein of the present invention, and typically it may be 22-32% (OPA test), for example 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, etc.

[0115] In some specific embodiments, the ash content of the hydrolyzed whey protein of the present invention is 5.5% by mass or less, preferably 5% by mass or less, and more preferably 4% by mass or less. Therefore, it is particularly suitable for preparing infant formula milk products.

[0116] In some specific embodiments, for the hydrolyzed whey protein of the present invention, intact α-lactalbumin and β-lactoglobulin are absent and the allergenic fragments are reduced by 99%.

[0117] In some other specific embodiments, the hydrolyzed whey protein of the present invention is preferably hydrolyzed whey protein powder. When the product is prepared by standard mixing (solid content 12.5% ​​by mass, room temperature), the osmotic pressure of the obtained solution is below 300 mOsm / kg H2O, for example, 265~300 mOsm / kg H2O, and the preferred osmotic pressure is 285~300 mOsm / kg H2O.

[0118] In some specific embodiments, for the hydrolyzed whey protein of the present invention, its powder density is 300 mL / 100 g or less, preferably 280 mL / 100 g, more preferably 240 mL / 100 g, and further preferably the powder density is 100-240 mL / 100 g.

[0119] The third aspect

[0120] In the third aspect of the present invention, a food is provided, which includes or uses the hydrolyzed whey protein described in the second aspect of the present invention. Exemplary, the food includes a liquid milk containing hydrolyzed whey protein, a hydrolyzed whey protein powder or a solid food containing hydrolyzed whey protein. In principle, such food is suitable for all people, especially for special groups such as infants, children, pregnant women, and the elderly.

[0121] The present invention does not particularly limit the form in which the hydrolyzed whey protein is used. For example, the hydrolyzed whey protein may be used in a liquid, solid or semi-solid form.

[0122] The preparation process of hydrolyzed whey protein is shown in the attached Figure 1 :

[0123] Step 1: Selection of whey protein raw materials

[0124] The concentrated whey protein powder WPC80 having an ash content of 4.0% by mass or less was selected.

[0125] Step 2: Preparation of whey protein aqueous solution

[0126] Add a certain amount of process water to the enzymolysis tank, start the material pump, and start circulating heating. When the temperature rises to 50-60°C, start the vacuum mixer to extract material from the powder bin and circulate the material. After the powder bin is extracted, circulate the material for 10-20 minutes (to ensure the hydration effect), and pump the hydrated liquid to the enzymolysis tank to prepare a whey protein aqueous solution with a mass concentration of 7-13%.

[0127] Step 3: Preparation of alkaline solution

[0128] Acidity regulators are added, including but not limited to one or more of food-grade sodium bicarbonate, sodium citrate, potassium carbonate, disodium hydrogen phosphate, dipotassium hydrogen phosphate, potassium hydroxide, and sodium hydroxide, to adjust the pH value to 6.5-7.5.

[0129] Step 4: Preparation of protease solution

[0130] Add a certain amount of pure water (room temperature) to the enzyme lysis tank. After adding water, add one or more proteases including but not limited to alkaline protease, trypsin, pepsin, acid protease, neutral protease, and flavor protease according to 1-3% (w / w) of the protein content in the protein solution, start stirring, stir and dissolve at room temperature for 2-3 minutes, and add the protease solution to the enzymolysis tank by bottom pulse feeding.

[0131] Step 5: Hydrolysis

[0132] Start timing after adding the protease solution, maintain the hydrolysis temperature stable in the range of 50~60℃, keep stirring on, and the hydrolysis time is 85~95min.

[0133] Step 6: Inactivate enzymes

[0134] After the hydrolysis time is over, the enzyme inactivation begins at a temperature of 105-110°C for 15-30 seconds and an outlet temperature of 5-10°C. The enzyme inactivation parameters are selected based on the enzyme with the highest inactivation temperature and time requirements, and at the same time, the protein solution must not be denatured due to the heating of the enzyme inactivation.

[0135] Step 7: Evaporation and Concentration

[0136] It adopts three-effect falling film evaporation concentration, with preheating temperature of 40~50℃, first effect temperature of 65~75℃, second effect temperature of 55~65℃, third effect temperature of 50~60℃, hot pressure pump pressure of 3.0~5.0bar, and liquid outlet concentration of 30~45%.

[0137] Step 8: Spray Drying

[0138] The liquid temperature is 50~60℃, the inlet air temperature is 170~190℃, and the exhaust air temperature is 75~85℃.

[0139] The hydrolyzed whey protein obtained by the method of the present invention can be widely applied to various groups of people, and is especially suitable for formula milk products for infants and young children.

[0140] Example

[0141] The embodiments of the present invention will be described in detail below in conjunction with the examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be considered to limit the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be obtained commercially.

[0142] The alkaline protease Alcalase Conc.BG (enzyme activity 12.5-14.25 AU-A / g) and flavor protease Flavourzyme 500MG (aminopeptidase, enzyme activity ≥500-550 LAPU / g) used in the examples of the present invention are produced by Novozymes. The concentrated whey protein powder WPC80 is produced by Angepu.

[0143] The detection method adopted by the present invention is as follows:

[0144] 1) Protein content detection: GB5009.5 first method is adopted.

[0145] 2) Ash content detection: adopt GB5009.4 first method.

[0146] 3) Hydrolysis degree detection: OPA method is used.

[0147] 4) Molecular weight determination: refer to GB / T 22729-2008.

[0148] 5) Detection of α-lactalbumin and β-lactoglobulin: T / TDSTIA 026-2022 Determination of α-lactalbumin and β-lactoglobulin in infant formula - Gel Permeation Chromatography was used.

[0149] 6) β-lactoglobulin allergen detection: Beta-lactoglobulin Residue Detection ELISA kit was used to detect β-lactoglobulin allergenicity.

[0150] 7) Osmotic pressure test: Use the German Rose OM-815 osmotic pressure tester to test the product osmotic pressure after dissolving it in the infant formula milk powder (stage 1) mixing ratio (12.5%).

[0151] 8) Powder density test: Use a powder density meter to measure. Pour 100g of finished powder into the density meter and flatten the powder with a stainless steel pressing plate. Vibrate 100 times and then press the powder flat again with an iron plate. Read the result with your eyes level, which is regarded as the powder density.

[0152] Embodiment 1:

[0153] Hydrolyzed whey protein powder, obtained by:

[0154] Step 1: Select concentrated whey protein powder WPC80 with ash content less than 4.0%.

[0155] Step 2: Add a certain amount of process water to the enzymolysis tank, start the material pump, and start circulating heating. When the temperature rises to 55°C, start the vacuum mixer to extract material from the powder bin and circulate the material. After the powder bin is extracted, circulate the material for 15 minutes (to ensure the hydration effect), and pump the hydrated liquid to the enzymolysis tank to prepare a whey protein aqueous solution with a temperature of 55°C and a mass concentration of 10%.

[0156] Step 3: Mix and dissolve a certain amount of potassium hydroxide and pure water, stir thoroughly to dissolve, then add the potassium hydroxide solution into the enzymatic hydrolysis tank by bottom pulse feeding, and adjust the pH in the enzymatic hydrolysis tank to 7.0.

[0157] Step 4: Add a certain amount of pure water (room temperature) to the enzyme lysis tank. After the water is added, add alkaline protease and flavor protease. The addition amount is 2% of the substrate protein content, and the ratio of alkaline protease to flavor protease is 3:7. Start stirring and stir and dissolve at room temperature for 3 minutes. When the temperature in the enzymatic hydrolysis tank is maintained at 55°C and pH 7.0, add the protease solution (i.e., the compound solution of alkaline protease and flavor protease) into the enzymatic hydrolysis tank by bottom pulse feeding.

[0158] Step 5: Start timing after adding the protease solution, maintain the hydrolysis temperature stable at 55°C, keep stirring on, and the hydrolysis time is 90 minutes.

[0159] Step 6: After the hydrolysis time is over, enzyme inactivation begins at a temperature of 110°C for 20 seconds and an outlet temperature of 8°C.

[0160] Step 7: The enzyme-inactivated liquid is concentrated by three-effect falling film evaporation, with a preheating temperature of 45°C, a first-effect temperature of 70°C, a second-effect temperature of 65°C, a third-effect temperature of 60°C, a hot pressure pump pressure of 4.5 bar, and a discharge liquid concentration of 35%.

[0161] Step 8: The feed concentration of spray drying is the same as the discharge concentration of the evaporator, the feed liquid temperature is 55°C, the inlet air temperature is 185°C, and the exhaust air temperature is 75°C.

[0162] Embodiment 2:

[0163] Hydrolyzed whey protein powder, obtained by:

[0164] Step 1: Select concentrated whey protein powder WPC80 with ash content less than 4.0%.

[0165] Step 2: Add a certain amount of process water to the enzymolysis tank, start the material pump, and start circulating heating. When the temperature rises to 50°C, start the vacuum mixer to extract material from the powder bin and circulate the material. After the powder bin is extracted, circulate the material for 15 minutes (to ensure the hydration effect), and pump the hydrated liquid to the enzymolysis tank to prepare a whey protein aqueous solution with a temperature of 50°C and a mass concentration of 8%.

[0166] Step 3: Mix and dissolve a certain amount of potassium hydroxide and pure water, stir thoroughly to dissolve, then add the potassium hydroxide solution into the enzymatic hydrolysis tank by bottom pulse feeding, and adjust the pH in the enzymatic hydrolysis tank to 6.5.

[0167] Step 4: Add a certain amount of pure water (room temperature) to the enzyme lysis tank. After the water is added, add alkaline protease and flavor protease. The added amount is 2% of the substrate protein content, and the ratio of alkaline protease to flavor protease is 3:7. Start stirring and stir and dissolve at room temperature for 3 minutes. When the temperature in the enzymolysis tank is maintained at 50°C and pH 6.5, add the protease solution (i.e., the compound solution of alkaline protease and flavor protease) into the enzymolysis tank by bottom pulse feeding.

[0168] Step 5: Start timing after adding the protease solution, maintain the hydrolysis temperature stable at 50°C, keep stirring on, and the hydrolysis time is 85 minutes.

[0169] Step 6: After the hydrolysis time is over, enzyme inactivation begins at a temperature of 110°C for 20 seconds and an outlet temperature of 8°C.

[0170] Step 7: The enzyme-inactivated liquid is concentrated by three-effect falling film evaporation, with a preheating temperature of 45°C, a first-effect temperature of 70°C, a second-effect temperature of 65°C, a third-effect temperature of 60°C, a hot pressure pump pressure of 4.5 bar, and a liquid outlet concentration of 35%.

[0171] Step 8: The feed concentration of spray drying is the same as the discharge concentration of the evaporator, the feed liquid temperature is 55°C, the inlet air temperature is 185°C, and the exhaust air temperature is 75°C.

[0172] Embodiment 3:

[0173] Hydrolyzed whey protein powder, obtained by:

[0174] Step 1: Select concentrated whey protein powder WPC80 with ash content less than 4.0%.

[0175] Step 2: Add a certain amount of process water to the enzymolysis tank, start the material pump, and start circulating heating. When the temperature rises to 60°C, start the vacuum mixer to extract material from the powder bin and circulate the material. After the powder bin is extracted, circulate the material for 15 minutes (to ensure the hydration effect), and pump the hydrated liquid to the enzymolysis tank to prepare a whey protein aqueous solution with a temperature of 60°C and a mass concentration of 12%.

[0176] Step 3: Mix and dissolve a certain amount of potassium hydroxide and pure water, stir thoroughly to dissolve, then add the potassium hydroxide solution into the enzymatic hydrolysis tank by bottom pulse feeding, and adjust the pH in the enzymatic hydrolysis tank to 7.5.

[0177] Step 4: Add a certain amount of pure water (room temperature) to the enzyme lysis tank. After the water is added, add alkaline protease and flavor protease. The added amount is 2% of the substrate protein content, and the ratio of alkaline protease to flavor protease is 3:7. Start stirring and stir and dissolve at room temperature for 3 minutes. When the temperature in the enzymatic hydrolysis tank is maintained at 60°C and pH 7.5, add the protease solution (i.e., the compound solution of alkaline protease and flavor protease) into the enzymatic hydrolysis tank by bottom pulse feeding.

[0178] Step 5: Start timing after adding the protease solution, maintain the hydrolysis temperature stable at 60°C, keep stirring on, and the hydrolysis time is 95 minutes.

[0179] Step 6: After the hydrolysis time is over, enzyme inactivation begins at a temperature of 110°C for 20 seconds and an outlet temperature of 8°C.

[0180] Step 7: The enzyme-inactivated liquid is concentrated by three-effect falling film evaporation, with a preheating temperature of 45°C, a first-effect temperature of 70°C, a second-effect temperature of 65°C, a third-effect temperature of 60°C, a hot pressure pump pressure of 4.5 bar, and a liquid outlet concentration of 35%.

[0181] Step 8: The feed concentration of the spray drying is the same as the discharge concentration of the evaporator, the feed liquid temperature is 55°C, the inlet air temperature is 185°C, and the exhaust air temperature is 75°C.

[0182] Comparative Example 1:

[0183] Step 1: Select concentrated whey protein powder WPC80 with ash content > 4.0%.

[0184] Step 2: Add a certain amount of process water to the enzymolysis tank, start the material pump, and start circulating heating. When the temperature rises to 55°C, start the vacuum mixer to extract material from the powder bin and circulate the material. After the powder bin is extracted, circulate the material for 15 minutes (to ensure the hydration effect), and pump the hydrated liquid to the enzymolysis tank to prepare a whey protein aqueous solution with a temperature of 55°C and a mass concentration of 10%.

[0185] Step 3: Mix and dissolve a certain amount of potassium hydroxide and pure water, stir and dissolve thoroughly, and then add the potassium hydroxide solution into the enzymatic hydrolysis tank by bottom pulse feeding to adjust the pH in the enzymatic hydrolysis tank to 7.0.

[0186] Step 4: Add a certain amount of pure water (room temperature) to the enzyme lysis tank. After the water is added, add alkaline protease and flavor protease. The added amount is 2% of the substrate protein content, and the ratio of alkaline protease to flavor protease is 3:7. Start stirring and stir and dissolve at room temperature for 3 minutes. When the temperature in the enzymatic hydrolysis tank is maintained at 55°C and pH 7.0, add the protease solution (i.e., the compound solution of alkaline protease and flavor protease) into the enzymatic hydrolysis tank by bottom pulse feeding.

[0187] Step 5: Start timing after adding the protease solution, maintain the hydrolysis temperature stable at 55°C, keep stirring on, and the hydrolysis time is 90 minutes.

[0188] Step 6: After the hydrolysis time is over, enzyme inactivation begins at a temperature of 110°C for 20 seconds and an outlet temperature of 8°C.

[0189] Step 7: The enzyme-inactivated liquid is concentrated by three-effect falling film evaporation, with a preheating temperature of 45°C, a first-effect temperature of 70°C, a second-effect temperature of 65°C, a third-effect temperature of 60°C, a hot pressure pump pressure of 4.5 bar, and a liquid outlet concentration of 35%.

[0190] Step 8: The feed concentration of spray drying is the same as the discharge concentration of the evaporator, the feed liquid temperature is 55°C, the inlet air temperature is 185°C, and the exhaust air temperature is 75°C.

[0191] In comparative example 1, when concentrated whey protein powder WPC80 with an ash content greater than 4.0% is selected as raw material in step 1, the test results of the final product show that the ash content is greater than 5.5%, which does not meet the requirements for the use of whey protein powder in the detailed rules for the review of infant formula production licenses and cannot be used for the production of infant formula powder.

[0192] Comparative Example 2:

[0193] Step 1: Select concentrated whey protein powder WPC80 with ash content less than 4.0%.

[0194] Step 2: Add a certain amount of process water to the enzymolysis tank, start the material pump, and start circulating heating. When the temperature rises to 55°C, start the vacuum mixer to extract material from the powder bin and circulate the material. After the powder bin is extracted, circulate the material for 15 minutes (to ensure the hydration effect), and pump the hydrated liquid to the enzymolysis tank to prepare a whey protein aqueous solution with a temperature of 55°C and a mass concentration of 5%.

[0195] Step 3: Mix and dissolve a certain amount of potassium hydroxide and pure water, stir thoroughly to dissolve, then add the potassium hydroxide solution into the enzymatic hydrolysis tank by bottom pulse feeding, and adjust the pH in the enzymatic hydrolysis tank to 7.0.

[0196] Step 4: Add a certain amount of pure water (room temperature) to the enzyme lysis tank. After the water is added, add alkaline protease and flavor protease. The addition amount is 2% of the substrate protein content, and the ratio of alkaline protease to flavor protease is 3:7. Start stirring and stir and dissolve at room temperature for 3 minutes. When the temperature in the enzymatic hydrolysis tank is maintained at 55°C and pH 7.0, add the protease solution (i.e., the compound solution of alkaline protease and flavor protease) into the enzymatic hydrolysis tank by bottom pulse feeding.

[0197] Step 5: Start timing after adding the protease solution, maintain the hydrolysis temperature stable at 55°C, keep stirring on, and the hydrolysis time is 90 minutes.

[0198] Step 6: After the hydrolysis time is over, enzyme inactivation begins at a temperature of 110°C for 30 seconds and an outlet temperature of the enzyme inactivation liquid of 8°C.

[0199] Step 7: The enzyme-inactivated liquid is concentrated by three-effect falling film evaporation, with a preheating temperature of 45°C, a first-effect temperature of 70°C, a second-effect temperature of 65°C, a third-effect temperature of 60°C, a hot pressure pump pressure of 4.5 bar, and a maximum outlet concentration of 23%.

[0200] Step 8: The feed concentration of spray drying is the same as the discharge concentration of the evaporator, the feed liquid temperature is 55°C, the inlet air temperature is 185°C, and the exhaust air temperature is 75°C.

[0201] In step 2 of comparative example 2, a whey protein aqueous solution with a mass concentration of 5% is prepared, and the water content is high. In step 7, the solid content of the concentrate outlet concentration can only reach 23%. The spray-dried product obtained in step 8 has a fine particle size and poor solubility. Since a large amount of water needs to be evaporated, the production process has high energy consumption.

[0202] Comparative Example 3:

[0203] Step 1: Select concentrated whey protein powder WPC80 with ash content less than 4.0%.

[0204] Step 2: Add a certain amount of process water to the enzymolysis tank, start the material pump, and start circulating heating. When the temperature rises to 55°C, start the vacuum mixer to extract material from the powder bin and circulate the material. After the powder bin is extracted, circulate the material for 15 minutes (to ensure the hydration effect), and pump the hydrated liquid to the enzymolysis tank to prepare a whey protein aqueous solution with a temperature of 55°C and a mass concentration of 15%.

[0205] Step 3: Mix and dissolve a certain amount of potassium hydroxide and pure water, stir thoroughly to dissolve, then add the potassium hydroxide solution into the enzymatic hydrolysis tank by bottom pulse feeding, and adjust the pH in the enzymatic hydrolysis tank to 7.0.

[0206] Step 4: Add a certain amount of pure water (room temperature) to the enzyme lysis tank. After the water is added, add alkaline protease and flavor protease. The addition amount is 2% of the substrate protein content, and the ratio of alkaline protease to flavor protease is 3:7. Start stirring and stir and dissolve at room temperature for 3 minutes. When the temperature in the enzymatic hydrolysis tank is maintained at 55°C and pH 7.0, add the protease solution (i.e., the compound solution of alkaline protease and flavor protease) into the enzymatic hydrolysis tank by bottom pulse feeding.

[0207] Step 5: Start timing after adding the protease solution, maintain the hydrolysis temperature stable at 55°C, keep stirring on, and the hydrolysis time is 90 minutes.

[0208] Step 6: After the hydrolysis time is over, the enzyme inactivation begins at a temperature of 110°C for 20 seconds.

[0209] In step 2 of comparative example 3, a whey protein aqueous solution with a mass concentration of 15% was prepared. In step 6, after the enzyme was inactivated, it was found that the protein in comparative example 3 was severely denatured and could not be concentrated.

[0210] Test example:

[0211] 1. Protein content

[0212] The protein content in the product was detected by the first method (Kjeldahl nitrogen determination method) in GB5009.5. The result showed that the protein content in the product obtained in Example 1 was 75% (based on total dry weight).

[0213] 2. Amino Acid Composition

[0214] The essential amino acid composition of the WPC80 raw material and the product prepared in Example 1 of the present invention was detected by high performance liquid chromatography. The results are shown in Table 1:

[0215] Table 1:

[0216]

[0217] As shown in Table 1, the types and contents of essential amino acids in the product of the present invention are basically consistent with those of the WPC80 raw material, indicating that the nutrients in the hydrolyzed whey protein are well retained, which may be due to the fact that no concentration processes such as membrane filtration and nanofiltration are used in the preparation process.

[0218] 3. Determination of hydrolysis degree and molecular weight

[0219] The whey protein aqueous solution in the present invention is not subjected to pre-denaturation treatment. After hydrolysis according to the type and amount of the enzyme added, the hydrolysis degree and molecular weight of the products obtained in Examples 1-3 and Comparative Example 2 are shown in Table 2.

[0220] Table 2:

[0221]

[0222] As can be seen from Table 2, the products obtained by the present invention have more favorable degree of hydrolysis and molecular weight overall.

[0223] 4. Determination of α-lactalbumin and β-lactoglobulin content

[0224] The contents of α-lactalbumin and β-lactoglobulin in the products obtained in Example 1 and Comparative Example 2 and the WPC80 raw material were tested. The results are shown in Table 3. The chromatograms of the products obtained in Example 1 and the WPC80 raw material are shown in Table 4. Figure 2~Figure 3 .

[0225] Table 3:

[0226]

[0227] From Table 3 and Figure 2~Figure 3 It can be seen that the hydrolyzed whey protein powder obtained by the present invention does not contain complete α-lactalbumin and β-lactoglobulin under the quantitative limit of the T / TDSTIA 026-2022 method (the quantitative limit of α-lactalbumin is 250.0 mg / kg, and the quantitative limit of β-lactoglobulin is 500.0 mg / kg), which has obvious advantages over the existing invention.

[0228] 5. β-lactoglobulin content allergenicity test

[0229] The sensitization of β-lactoglobulin of WPC80 raw material, Example 1 and Comparative Example 2 was detected by using an enzyme-linked immunosorbent assay kit. The results are shown in Table 4:

[0230] Table 4:

[0231]

[0232] As shown in Table 4, compared with the WPC80 raw material, the β-lactoglobulin allergenicity of the product obtained by the present invention is reduced by 98.87%.

[0233] 6. Osmotic pressure test

[0234] The products obtained in Example 1 and Comparative Example 2 were reconstituted using a 1-stage infant formula milk powder (concentration 12.5%), and their osmotic pressures were tested using a German Rose OM-815 osmotic pressure tester. The results are shown in Table 5:

[0235] Table 5:

[0236]

[0237] Literature (Jie Liang. Analysis of osmotic pressure and influencing factors of breast milk and infant formula solutions [J]. Food Industry, 2021, 42(04): 254-257.) shows that the osmotic pressure of breast milk is around 300 mOsm / kg H2O, which does not put infants at risk of high osmotic pressure. Therefore, the osmotic pressure of the product obtained by the present invention meets the needs of infants and young children.

[0238] 7. Powder density detection

[0239] The powder densities of the products obtained in Examples 1-3 and Comparative Example 2 were measured using a powder density meter. The results are shown in Table 6:

[0240] Table 6:

[0241]

[0242] It can be seen from Table 6 that the powder density of the product obtained in Comparative Example 2 is much greater than that of Examples 1-3.

[0243] It should be noted that, although the technical solution of the present invention is introduced with specific examples, those skilled in the art will appreciate that the present invention should not be limited thereto.

[0244] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for preparing hydrolyzed whey protein, characterized in that: The method comprises the following steps: Dissolving step: dissolving the whey protein raw material in water to obtain an aqueous solution with a solid content of 7 to 13% by mass and a pH value of 6.5 to 7.5; The hydrolysis step is: hydrolyzing the whey protein aqueous solution in the presence of a complex enzyme, wherein the hydrolysis temperature is 50-60° C.; Concentration step: concentrating the hydrolyzed solution system to a solid content of 30-45% by mass; The ash content in the whey protein raw material is 4% by mass or less.

2. The preparation method according to claim 1, characterized in that: In the dissolving step, the dissolving temperature is 50-60°C.

3. The preparation method according to claim 1 or 2, characterized in that: In the dissolving step, an alkaline substance is added to adjust the pH value of the aqueous solution.

4. The preparation method according to claim 1 or 2, characterized in that: In the hydrolysis step, the composite enzyme is a combination of endoprotease and exoprotease; the amount of the composite enzyme used is 1-3% by mass of the protein in the system.

5. The preparation method according to claim 4, characterized in that: In the hydrolysis step, the endoprotease includes a serine endoprotease; the exoprotease includes an aminopeptidase.

6. The preparation method according to claim 1 or 2, characterized in that: In the hydrolysis step, the hydrolysis time does not exceed 100 minutes.

7. The preparation method according to claim 1 or 2, characterized in that: The method further comprises an enzyme inactivation step after the hydrolysis step and before the concentration step.

8. The preparation method according to claim 1 or 2, characterized in that: In the step of concentration, triple-effect falling film evaporation is used for concentration.

9. The preparation method according to claim 1 or 2, characterized in that: The prepared whey protein hydrolysate has a protein component with a molecular weight greater than 10,000 Da in an amount of 7.5% by mass or less; The content is based on dry weight.

10. The preparation method according to claim 1 or 2, characterized in that: The degree of hydrolysis of the prepared hydrolyzed whey protein is 22% to 32%.

11. The preparation method according to claim 1 or 2, characterized in that: The prepared hydrolyzed whey protein is configured as a reconstituted liquid with a concentration of 12.5% ​​by mass, and its osmotic pressure at room temperature is less than 300 mOsm / kg H2O.

12. A food comprising or using the hydrolyzed whey protein prepared by the preparation method according to any one of claims 1 to 11.

Images