Highly resistant dairy product and method for its preparation

Abstract

The present application relates to the technical field of dairy products, and provides a highly tolerable dairy product and a preparation method thereof, wherein the raw milk of the dairy product contains beta-lactoglobulin and lactose, and the dairy product is prepared by pretreatment, ultrahigh pressure homogenization, enzymolysis and post-treatment of the raw milk; the ultrahigh pressure homogenization promotes the hydrolysis of the beta-lactoglobulin and / or the lactose in the enzymolysis process; the enzymolysis is performed after the ultrahigh pressure homogenization, the equipment used in the ultrahigh pressure homogenization contains at least two jet cavities, a microchannel is arranged in the jet cavity, the microchannel is used for jetting a liquid to impact the inner wall of the jet cavity or for interactive collision of jetted liquids; and the liquid is the pretreated raw milk. By means of the synergistic cooperation between the processes, the present application realizes the preparation of a highly tolerable dairy product while retaining higher nutritional ingredients, and the dairy product has excellent flavor and taste.

Description

Technical Field

[0001] This invention relates to the field of dairy product technology, and in particular to a highly tolerable dairy product and its preparation method. Background Technology

[0002] Milk is a recognized source of high-quality nutrition, but some differences between it and human milk limit its consumption globally. For example, some people experience milk protein allergies or lactose intolerance. Therefore, the industry has proposed a type of highly tolerable dairy product, which refers to specially processed dairy products suitable for specific groups, primarily aimed at reducing the risk of adverse reactions after consumption. This includes lactose-free milk for lactose intolerance and extensively hydrolyzed protein products for bovine milk protein allergies.

[0003] Currently, the preparation of these products mainly focuses on the treatment of β-lactoglobulin (β-Lg) and lactose in milk raw materials, aiming to denature, reduce, or even completely remove them through heat treatment, enzymatic hydrolysis, and physical separation. However, β-lactoglobulin (β-Lg) is a heat-resistant protein with strong resistance to enzymatic hydrolysis. This limits the effectiveness of heat treatment and enzymatic hydrolysis in reducing adverse reactions after consumption. Therefore, in the preparation of high-tolerance dairy products dominated by this technology, the high intensity of heat treatment can easily destroy heat-sensitive vitamins, trigger Maillard reactions, or cause excessive enzymatic hydrolysis to produce large amounts of bitter peptides, seriously affecting the product's nutritional value, flavor, and taste. Physical separation, which involves the indiscriminate separation of other beneficial proteins (such as whey protein), also suffers from significant nutritional loss. Summary of the Invention

[0004] Studies have found that numerous factors influence adverse reactions after consuming dairy products made from milk. To achieve higher tolerance while retaining higher nutritional content, this invention employs enzymatic hydrolysis as the core process. This process utilizes both the hydrolysis of β-lactoglobulin by proteases and the hydrolysis of lactose by lactase. However, it has been found that optimizing the enzymatic hydrolysis process has limited effect on improving the tolerance of the prepared dairy products, and may even lead to incomplete lactose breakdown. Therefore, this invention provides a highly tolerable dairy product and its preparation method. Based on the aforementioned enzymatic hydrolysis as the core process, a novel process flow is proposed. By utilizing the synergistic effect between various processes, a more tolerable dairy product is prepared while retaining higher nutritional content, resulting in superior flavor and texture.

[0005] Specifically, the present invention provides a dairy product, wherein the raw milk of the dairy product contains β-lactoglobulin and lactose, and the dairy product is prepared by pretreatment, ultra-high pressure homogenization, enzymatic hydrolysis and post-treatment of the raw milk; the ultra-high pressure homogenization promotes the hydrolysis of β-lactoglobulin and / or lactose during the enzymatic hydrolysis process; The enzymatic hydrolysis is performed after the ultra-high pressure homogenization. The ultra-high pressure homogenization equipment includes a jet cavity, and the jet cavity is provided with at least two microchannels. The microchannels are used for spraying liquid to impact the inner wall of the jet cavity or for spraying liquid to interact and collide. The liquid is the pretreated raw milk. The enzymatic hydrolysis involves adding a protease to the system for a first enzymatic hydrolysis, followed by enzyme inactivation to obtain a first enzymatic hydrolysate, and then adding lactase to the first enzymatic hydrolysate for a second enzymatic hydrolysis to obtain a second enzymatic hydrolysate.

[0006] Traditional homogenization techniques typically operate at pressures of 20–60 MPa. Literature indicates that with advancements in equipment manufacturing capabilities, the maximum pressure of homogenization equipment has increased to 400 MPa. Homogenization techniques operating at pressures above 60 MPa are generally referred to as ultra-high pressure homogenization (UHPH).

[0007] To address the aforementioned technical bottlenecks in the preparation of highly tolerable dairy products, this invention introduces a specific ultra-high pressure homogenization process and a specific enzymatic hydrolysis process. It has been found that this specific ultra-high pressure homogenization process significantly promotes the enzymatic hydrolysis of β-lactoglobulin and lactose under this process, resulting in a significant improvement in the tolerability of the obtained dairy products. This is because this specific ultra-high pressure homogenization process combines instantaneous pressure relief (expansion), high-speed impact, high shear, and thermal synergistic effects. It can open up the tight spatial conformation of β-lactoglobulin, disrupting its tertiary and secondary structures, unfolding the molecule, and exposing its internal enzyme cleavage sites and internal hydrophobic groups, thereby significantly overcoming its natural resistance to enzymatic hydrolysis. Furthermore, it improves the substrate accessibility of enzymes by mechanically breaking down the microstructure of lactose; and it also directly or indirectly improves the overall efficiency of subsequent enzymatic reactions through instantaneous physical changes (such as temperature increase) and possible enzyme conformational relaxation.

[0008] The ultra-high pressure homogenization process alters the conformation of β-lactoglobulin, significantly improving the enzymatic hydrolysis efficiency of the protease in the first stage and even affecting the structure of the resulting hydrolysate. Furthermore, the ultra-high pressure homogenization process changes the conformational distribution and crystal structure of lactose, altering its interaction with β-lactoglobulin. In the presence of this structurally modified lactose, the protease directly acts on β-LG, resulting in more complete β-LG cleavage and subsequent more thorough lactose hydrolysis. The addition of lactase immediately degrades lactose, inhibiting the Maillard reaction between protein hydrolysis products (such as lysine) and lactose, preserving flavor, and reducing side reactions. However, if protease and lactase are added simultaneously, or if lactase is added first for hydrolysis followed by protease, the presence of inhibitors or metal ions in the lactase preparation can affect the optimal pH environment for the protease, interfering with its activity. Simultaneous reactions may also lead to the inhibition of lactase activity under high protease activity, resulting in incomplete lactose decomposition and poor reaction efficiency. More importantly, the study found that, compared with various ultra-high pressure homogenization technologies such as slit-type ultra-high pressure microjet homogenization, Y-type fusion collision cavity homogenization, Z-type microchannel cavity homogenization, and NiSoX valve-type ultra-high pressure homogenization technology, the specific ultra-high pressure homogenization treatment of the present invention combined with the prior proteolytic process has a significant promoting effect on the subsequent enzymatic hydrolysis of lactase.

[0009] Specifically, the extreme shear force of ultra-high pressure processing (up to 10) 8 s -1 This process forcibly unfolds the β-Lg conformation, increasing the hydrophobicity of the protein surface by 40-60%, and improving the enzymatic hydrolysis efficiency of subsequent proteases by 2-3 times. Ultimately, this allows the product to achieve a lactose content below 0.09g / 100mL while maintaining an IgE binding rate of β-lactoglobulin below 29% of the raw milk, effectively solving the allergy problem. The entire core process is carried out under non-heat or mild heat conditions, effectively avoiding the destruction of heat-sensitive nutrients such as vitamins and functional proteins caused by traditional high-temperature treatments. Protein retention can reach over 95%, and active protein retention can reach over 90%.

[0010] Studies have found that if the channel pore size is too large, the fluid experiences low resistance within the wide channel, making it difficult to quickly convert kinetic energy into heat and impact force. This weakens the collision force, making it difficult to effectively disrupt the tight conformation of β-lactoglobulin or completely cleave lactose crystals. Insufficient processing of proteins and lactose leads to decreased tolerance (more easily degraded by enzymes, shortening shelf life). If the channel pore size is too small, the extremely high flow resistance results in excessive pressure drop, generating excessively high instantaneous temperatures and shear forces. Although this can thoroughly open the protein conformation, excessive high temperatures and shear can easily lead to protein aggregation, denaturation, or an increase in bitter substances, thus damaging the sensory quality of the dairy product. Although enzyme tolerance may improve, the overall quality (taste, consistency, color) is impaired, resulting in decreased actual usability. In the dairy product provided by the present invention, the microchannel is made of diamond, and the channel pore size is 50~100μm, preferably 75μm.

[0011] According to the dairy product provided by the present invention, the parameters of the ultra-high pressure homogenization include a first-stage pressure of 50MPa~80MPa and a second-stage pressure of 150MPa~300MPa.

[0012] Preferably, the parameters of the ultra-high pressure homogenization include a first-stage pressure of 80 MPa and a second-stage pressure of 200-250 MPa.

[0013] β-lactoglobulin (β-Lg) in cow's milk is one of the most common food allergens in infants and adults. Its compact globular conformation and specific amino acid sequence (antigenic epitopes) can trigger IgE-mediated type I hypersensitivity reactions. Proteases cleave the unfolded β-lactoglobulin peptide chain, hydrolyzing β-Lg into smaller peptide fragments and disrupting its antigenic epitopes. Lactase hydrolyzes lactose in cow's milk into glucose and galactose, generating galactooligosaccharides (GOS), which have prebiotic functions.

[0014] The mass content of protease in the system during the first enzymatic hydrolysis is 2.5‰~3.0‰; the first enzymatic hydrolysis is carried out at 40~50℃ for 80~90 min, and the enzyme inactivation is carried out at 75~80℃ for 30~35 s.

[0015] The mass content of lactase in the system during the second enzymatic hydrolysis is 0.2‰~1.2‰, preferably 0.8‰; the second enzymatic hydrolysis is carried out at 3~6℃ for 2~4 hours.

[0016] If the enzymatic hydrolysis temperature is too high, it will cause a significant decrease or even inactivation of the enzyme, resulting in a reduction in the degree of hydrolysis, product yield, and reaction efficiency. If the enzymatic hydrolysis temperature is too low, it will cause a significant decrease in the reaction rate and a substantial increase in the reaction time. If the enzymatic hydrolysis time is too long, it will cause enzyme inactivation, product degradation, and quality deterioration. If the enzymatic hydrolysis time is too short, it will cause incomplete reaction, low product yield, and insufficient functionality. Therefore, preferably, the temperature of the first enzymatic hydrolysis is 40~45℃, and the time is 80~85 min; the temperature of the second enzymatic hydrolysis is 4~6℃, and the time is 2~2.5 h.

[0017] Preferably, the protease is a neutral protease, such as Alcalase 2.4L.

[0018] Preferably, the lactase is β-galactosidase.

[0019] The degree of hydrolysis refers to the hydrolysis of peptide bonds in a protein molecule, indicating the extent to which peptide bonds in a protein molecule are broken. The degree of hydrolysis is the ratio of the number of peptide bonds broken during hydrolysis to the total number of peptide bonds in the protein. In the dairy product provided by the present invention, the degree of enzymatic hydrolysis is 10-15%.

[0020] Studies have found that under the above-mentioned process of the present invention, for every 1% increase in degree of hydrolysis, the IgE binding rate decreases by about 2.2%. However, when the degree of hydrolysis is greater than 15%, the content of bitter peptides surges. The present invention strictly controls the degree of hydrolysis in the range of 10-15%, and by precisely controlling the degree of hydrolysis (DH), it effectively avoids the production of bitter peptides, so that the final product retains the rich taste and natural color of milk, and has high sensory acceptance.

[0021] According to the dairy product provided by the present invention, the liquid material is preheated to 15°C to 25°C and then subjected to ultra-high pressure homogenization.

[0022] The pretreatment described in this invention refers to standardized processes that may be involved in dairy product production. For example, the pretreatment includes centrifuging the raw milk at 45-55°C for skimmed or low-fat milk, followed by cooling for later use. The purpose of centrifugation is to control the fat content. If the skimmed raw milk is used directly in subsequent processes, the cooling process can be omitted. If the skimmed raw milk needs to be temporarily stored, it needs to be cooled to 2-6°C for later use. In some examples, fat can also be backfilled to achieve the desired fat content in the resulting dairy product.

[0023] For example, the pretreatment includes sterilization and separation at 45~55℃ to remove the total number of colonies and some spores, thereby extending the storage time of raw milk.

[0024] For example, for whole milk, the pretreatment includes milk separation at 45~55℃ to remove macromolecular cells and impurities.

[0025] According to the dairy product provided by the present invention, the raw milk contains β-lactoglobulin at a content of 3200 mg / L to 3500 mg / L and lactose at a content of 4.5 g / 100 g to 5.0 g / 100 g.

[0026] The pretreatment is used to remove one or more of the following: impurities, fats, and bacteria.

[0027] According to the dairy product provided by the present invention, the post-processing includes enzyme inactivation, sterilization, and homogenization.

[0028] To inactivate the enzyme, the post-treatment preferably includes heating to 110-150°C and maintaining the temperature for 0.09-6 seconds.

[0029] To obtain the dairy product with excellent overall performance, preferably, the post-processing includes: The second enzymatic hydrolysate was homogenized and then heated, followed by cooling and filling.

[0030] The homogenization is preferably carried out at 65~70°C and 230 bar / 45 bar.

[0031] The purpose of the heat treatment is to completely inactivate the activity of protease and lactase, preferably by holding at 121°C to 131°C for 2 to 6 seconds, and more preferably by holding at 127°C for 4 seconds. The cooling temperature is 2℃~6℃, preferably 4℃.

[0032] According to the dairy product provided by the present invention, the protein retention rate is above 95%, the active protein retention rate is above 90%, the IgE binding rate of β-lactoglobulin is below 30% of that of the raw milk, and the lactose content is below 0.1g / 100mL.

[0033] The present invention also provides a method for preparing the dairy product as described above, comprising: the raw milk of the dairy product contains β-lactoglobulin and lactose, and the dairy product is prepared by pretreatment, ultra-high pressure homogenization, enzymatic hydrolysis and post-treatment of the raw milk; the ultra-high pressure homogenization promotes the hydrolysis of β-lactoglobulin and / or lactose during the enzymatic hydrolysis process.

[0034] This invention provides a highly tolerable dairy product and its preparation method. Based on the above-mentioned enzymatic hydrolysis as the core process, it proposes a brand-new process flow. By utilizing the synergistic cooperation between various processes, it achieves the preparation of a more tolerable dairy product while retaining higher nutritional content, and it also has excellent flavor and taste.

[0035] This invention not only solves the problem of lactose intolerance, but also gives the product prebiotic function by producing galactooligosaccharides through hydrolysis, thus enhancing the product's health value.

[0036] This invention enables continuous and automated production, making it suitable for large-scale industrial applications. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0038] Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels. The models or parameters of some of the raw materials involved in the embodiments of this invention are shown below: Fresh raw milk: 3.2% protein, 3.5% fat, 4.8% lactose.

[0039] Lactase: Danisco Bonlacta.

[0040] Protease: Novozymes Alcalase 2.4L FG.

[0041] Ultra-high pressure homogenizer 1: Equipped with a 75μm diamond interactive nozzle, its structure is as described in Example 2 of CN 117652558 A.

[0042] Ultra-high pressure homogenizer 2: equipped with a 50μm diamond interactive nozzle, the structure of which is the structure described in Example 2 of CN 117652558 A.

[0043] Ultra-high pressure homogenizer 3: equipped with a 100μm diamond interactive nozzle, the structure of which is the structure described in Example 2 of CN 117652558 A.

[0044] Jacketed Continuous Stirred Reactor (CSTR): 300L capacity.

[0045] Example 1 A continuous production process for high-tolerance milk, the preparation method of which is as follows: (1) Take 100kg of fresh raw milk, centrifuge to remove fat, and then cool it to 4℃.

[0046] (2) After the skim milk cooled in step (1) is preheated to 20°C, it is processed by ultra-high pressure homogenizer 1. The processing parameters are set as follows: first-stage pressure 80MPa, second-stage pressure 200MPa, to obtain the first liquid.

[0047] (3) The first liquid obtained in step (2) is pumped into a jacketed continuous stirring reactor, heated to 45°C, and the pH is adjusted to 7.2. Then, 0.27 kg of protease is added for the first enzymatic hydrolysis. The temperature of the first enzymatic hydrolysis is 40~50°C and the time is 85 min. Then, the enzyme is inactivated at 75~80°C for 30~35 s. After cooling to 4°C, 0.08 kg of lactase is added. The reaction is carried out at a stirring speed of 60 rpm for 2 hours to obtain the second liquid.

[0048] (4) The second liquid obtained in step (3) is preheated by a tubular heat exchanger, homogenized at 230 bar / 45 bar at 68°C, held at 127°C for 4 seconds, and then cooled to 4°C for filling.

[0049] Example 2 The main difference from Example 1 is that the processing parameters in step (2) are: first-stage pressure 80MPa, second-stage pressure 250MPa.

[0050] Example 3 The main difference from Example 1 is that step (1) adds a fat backfilling process, in which 9 kg of fat that has been degreased by centrifugation is backfilled into skim milk and stirred evenly at 2~6℃.

[0051] Example 4 The main difference from Example 1 is that step (2) uses an ultra-high pressure homogenizer 2 for processing.

[0052] Example 5 The main difference from Example 1 is that step (2) uses an ultra-high pressure homogenizer 3 for processing.

[0053] Comparative Example 1 The main difference from Example 1 lies in step (2), as follows: (2) Heat the skim milk cooled in step (1) at 80°C for 30 minutes to obtain the first liquid.

[0054] Comparative Example 2 The main difference from Example 1 is that it does not include step (2), and the skim milk cooled in step (1) is directly subjected to step (3).

[0055] Comparative Example 3 The main difference from Example 1 is that the ultra-high pressure homogenizer in step (2) is the M-7125 microfluidics Co., Newton, Mass., USA. This equipment is equipped with a one-way high-strength plunger pump, is a valve-type ultra-high pressure homogenizer, and the processing parameters are set as follows: first-stage pressure 80MPa, second-stage pressure 200MPa, to obtain the first liquid.

[0056] Comparative Example 4 The main difference from Example 1 is that the first enzymatic hydrolysis temperature in step (3) is 55°C.

[0057] Comparative Example 5 The main difference from Example 1 is in step (3), which is as follows: (3) Pump the first liquid obtained in step (2) into a jacketed continuous stirring reactor, heat it to 45°C, adjust the pH to 7.2, then add 0.27 kg of protease for the first enzymatic hydrolysis. The temperature of the first enzymatic hydrolysis is 40~50°C and the time is 85 min. Then cool it down to 4°C and add 0.08 kg of lactase. React at a stirring speed of 60 rpm for 2 hours to obtain the second liquid.

[0058] Comparative Example 6 The main difference from Example 1 is in step (3), which is as follows: The first liquid obtained in step (2) is pumped into a jacketed continuous stirred reactor, cooled to 4°C, and then 0.08 kg of lactase is added. The reaction is carried out at a stirring speed of 60 rpm for 2 hours to obtain the second liquid.

[0059] Comparative Example 7 The main difference from Example 1 is that the ultra-high pressure homogenizer in step (2) adopts Nano-type micro-jet (NanoLab TYPE). This device is equipped with a one-way valve, pressurizes in the high-pressure chamber pump, and impacts the emulsification chamber at subsonic speed. It is designed as an emulsification chamber type ultra-high pressure homogenizer, and the processing parameters are set as follows: first-stage pressure 80MPa, second-stage pressure 200MPa, to obtain the first liquid.

[0060] Comparative Example 8 The main difference from Example 1 is that the ultra-high pressure homogenizer in step (2) adopts the Litu FB-110Z5 microjet, which is equipped with a turbulent fusion and collision chamber, and is designed as a Y-type valve group for ultra-high pressure homogenization. The processing parameters are set as follows: first-stage pressure 80MPa, second-stage pressure 200MPa, to obtain the first liquid.

[0061] Comparative Example 9 The main difference from Example 1 is that the ultra-high pressure homogenizer in step (2) adopts GEA NiSoX microjet. The device is equipped with a deflector and an interaction chamber. It is designed as a NiSoX valve type ultra-high pressure homogenizer, and the processing parameters are set as follows: first-stage pressure 80MPa, second-stage pressure 200MPa, to obtain the first liquid.

[0062] Test Example 1 The high-tolerance milk prepared in the above examples and comparative examples was subjected to the following comparative tests: (1) β-lactoglobulin IgE binding rate, the test method is referenced in the literature "Research on the relationship between DHPM stress β-lactoglobulin conformational changes and allergenicity".

[0063] (2) Lactose residue, the test method is: GB 5009.8-2023 National Food Safety Standard Determination of fructose, glucose, sucrose, maltose and lactose in food.

[0064] (3) Protein content, the test method is: GB 5009.5-2025 National Food Safety Standard - Determination of Protein in Food. The calculation method for protein retention rate is as follows: Protein retention rate (%) = (protein content in high-tolerance milk / milk protein content in fresh raw milk) × 100%.

[0065] (4) Degree of hydrolysis (DH), the test method is: GB / T 22492-2008: Degree of hydrolysis test procedure for soybean peptide powder (commonly pH-stat or colorimetric method).

[0066] (5) Active protein retention rate = (β-lactoglobulin in high-tolerance milk / β-lactoglobulin in fresh raw milk) × 100%. The test method for active protein content is NY / T 4630-2025 Determination of α-lactalbumin and β-lactoglobulin in milk and its products by high performance liquid chromatography.

[0067] (6) Sensory evaluation, the testing methods are in accordance with ISO 13299:2016 (Sensory analysis – Methodology – General guidance) and ISO 8586:2012 (Sensory analysis – Selection and training of sensory analysts).

[0068] (7) This invention uses the Gastrointestinal Discomfort Index (GSRS) to evaluate product tolerability. It is applicable to clinical research and efficacy evaluation of functional dyspepsia, irritable bowel syndrome (IBS), and related functional gastrointestinal disorders. The scale is divided into five dimensions based on the nature of symptoms, with each dimension containing several items. Subjects must select the corresponding score according to the actual severity of the symptoms. (Abdominal pain symptoms (abdominal pain, burning pain), acid reflux / heartburn (heartburn, acid regurgitation), nausea (nausea, vomiting), abdominal distension symptoms (abdominal distension, borborygmus), and abnormal bowel movements (diarrhea, constipation, urgency)). Specific testing methods refer to the study of the measurement characteristics of patients with gastrointestinal diseases using the Gastrointestinal Symptom Rating Scale.

[0069] The higher the total score, the more severe the gastrointestinal dysfunction. Generally, in clinical studies, a total gastrointestinal discomfort index score >12.5 is considered to indicate significant symptoms, requiring further intervention.

[0070] The test results are shown in Tables 1 and 2 below.

[0071] Table 1

[0072] Table 2

[0073] As can be seen from the above data, through the synergistic cooperation between the various processes in Examples 1 to 5 of the present invention, the protein retention rate is above 92%, the active protein retention rate is above 88%, the IgE binding rate of β-lactoglobulin is below 29% of the raw milk, and the lactose content is below 0.09g / 100mL, thereby achieving the preparation of dairy products with higher tolerance, excellent flavor and taste, and high active protein retention rate.

[0074] Comparative Example 1, processed using traditional high-temperature methods, resulted in decreased enzymatic hydrolysis efficiency, a significantly increased β-lactoglobulin IgE binding rate, and a markedly higher lactose residue. Simultaneously, the high temperature damaged functional proteins and other nutrients, reducing protein retention and the retention rate of active proteins. The product exhibited a distinct cooked flavor and a slight burnt flavor, resulting in poor taste and low product tolerance.

[0075] Comparative Example 2 lacked ultra-high pressure homogenization treatment, resulting in insufficient processing of protein and lactose. The binding rate of β-lactoglobulin IgE and the residual amount of lactose were significantly increased. Although the taste was not much different from that of ordinary milk, the product had low tolerance and a significantly increased gastrointestinal discomfort index, indicating impaired gastrointestinal function and requiring further intervention.

[0076] Comparative Example 3 used valve-type ultra-high pressure homogenization, which resulted in insufficient protein processing and a significantly increased β-lactoglobulin IgE binding rate. Although the taste was not significantly different from that of regular milk, the product had low tolerance and a significantly increased gastrointestinal discomfort index, indicating impaired gastrointestinal function and requiring further intervention.

[0077] Comparative Example 4 showed that the enzymatic hydrolysis temperature was too high, resulting in reduced enzyme activity, higher β-lactoglobulin IgE binding rate, a degree of hydrolysis greater than 15%, increased bitter peptide content, bitter taste, and lower product tolerance.

[0078] In Comparative Example 5, step (3) did not involve an enzyme inactivation step. Protease and lactase reacted simultaneously, resulting in the inhibition of lactase activity, incomplete lactose decomposition, poor taste, and low product tolerance.

[0079] Therefore, this application demonstrates that by introducing a specific ultra-high pressure homogenization process, it significantly promotes the enzymatic hydrolysis of β-lactoglobulin and lactose, and significantly improves the tolerability of the resulting dairy products. Furthermore, by utilizing the synergy between different preparation processes, it achieves the preparation of dairy products with higher tolerability while retaining higher nutritional content, resulting in products with excellent flavor and texture.

[0080] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A dairy product, characterized in that, The raw milk used in the dairy product contains β-lactoglobulin and lactose. The dairy product is prepared by pretreatment, ultra-high pressure homogenization, enzymatic hydrolysis, and post-treatment of the raw milk. The ultra-high pressure homogenization promotes the hydrolysis of β-lactoglobulin and / or lactose during the enzymatic hydrolysis process. The enzymatic hydrolysis is performed after the ultra-high pressure homogenization. The ultra-high pressure homogenization equipment includes a jet cavity, and the jet cavity is provided with at least two microchannels. The microchannels are used for spraying liquid to impact the inner wall of the jet cavity or for spraying liquid to interact and collide. The liquid is the pretreated raw milk. The enzymatic hydrolysis involves adding a protease to the system for a first enzymatic hydrolysis, followed by enzyme inactivation to obtain a first enzymatic hydrolysate, and then adding lactase to the first enzymatic hydrolysate for a second enzymatic hydrolysis to obtain a second enzymatic hydrolysate.

2. The dairy product according to claim 1, characterized in that, The microchannels are made of diamond and have a pore size of 50~100μm.

3. The dairy product according to claim 1, characterized in that, The parameters of the ultra-high pressure homogenizer include a first-stage pressure of 50MPa~80MPa and a second-stage pressure of 150MPa~300MPa.

4. The dairy product according to claim 1, characterized in that, The degree of hydrolysis of the enzyme is 10-15%.

5. The dairy product according to claim 1, characterized in that, The liquid feed is preheated to 15℃~25℃ before undergoing ultra-high pressure homogenization.

6. The dairy product according to claim 1, characterized in that, The raw milk contains β-lactoglobulin at a concentration of 3200 mg / L to 3500 mg / L, and lactose at a concentration of 4.5 g / 100 g to 5.0 g / 100 g.

7. The dairy product according to claim 1, characterized in that, The pretreatment is used to remove one or more of the following: impurities, fats, and bacteria.

8. The dairy product according to claim 1, characterized in that, The post-processing includes enzyme inactivation, sterilization, and homogenization.

9. The dairy product according to any one of claims 1 to 8, characterized in that, The dairy product has a protein retention rate of over 95%, an active protein retention rate of over 90%, an IgE binding rate of β-lactoglobulin of less than 30% of the raw milk, and a lactose content of less than 0.1g / 100mL.

10. A method for preparing the dairy product according to any one of claims 1 to 9, characterized in that, include: The raw milk used in the dairy product contains β-lactoglobulin and lactose. The dairy product is prepared by pretreatment, ultra-high pressure homogenization, enzymatic hydrolysis and post-treatment of the raw milk. The ultra-high pressure homogenization promotes the hydrolysis of β-lactoglobulin and / or lactose during the enzymatic hydrolysis process.

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