Composition, preparation method thereof and food

Abstract

The invention provides a composition as well as a preparation method and food thereof. The composition comprises micelle casein and a compound enzyme, the compound enzyme comprises pepsin, trypsin, chymotrypsin and glutamic acid protease. The composition contains the micelle casein and the compound enzyme, the hydrolysis degree of the micelle casein in vivo can be improved by adding the compound enzyme, rapid and complete absorption and utilization of the micelle casein are facilitated, and the nutritional value is improved.

Description

Technical Field

[0001] The present application relates to the field of food, and in particular, to a composition and a preparation method thereof and food. Background Art

[0002] Casein is one of the main proteins in cow's milk, accounting for about 80% of the total milk protein. It is a complex high-molecular protein composed of multiple amino acid residues, with high solubility and stability. In cow's milk, casein is mainly composed of three subtypes: β-CN, α-CN and κ-CN, of which α-CN is composed of αs1-CN and αs2-CN. These proteins are bound together by non-covalent bonds and combined with micellar calcium phosphate (CCP) to form casein micelles with a diameter of about 40-300nm. At present, micellar casein is mainly obtained by membrane separation.

[0003] The existing micellar casein powder has the following problems in practical applications: 1) Casein powder produced by conventional processes has poor solubility and low hydrolysis efficiency due to high heat intensity during the preparation process; 2) Natural casein mainly exists in the form of micelles, and some hydrophobic groups and enzyme cleavage sites exist inside the micelles, which makes the hydrolysis of casein difficult and the degree of hydrolysis low, affecting the complete absorption and utilization of casein by the human body; 3) Casein takes a long time to metabolize in the human body and cannot meet the human body's needs for rapid absorption of amino acids or proteins.

[0004] Therefore, the current micellar casein powder still needs to be studied. Summary of the invention

[0005] The present application aims to solve the technical problems existing in the prior art at least to a certain extent. To this end, the present application proposes a composition, a preparation method thereof and a food. The composition of the present application contains micellar casein and a complex enzyme. The addition of the complex enzyme can increase the hydrolysis degree of micellar casein in the body, which is conducive to its rapid and complete absorption and utilization, and improves the nutritional value.

[0006] In one aspect of the present application, the present application provides a composition. According to an embodiment of the present application, the composition comprises: micellar casein and a composite enzyme; the composite enzyme comprises pepsin, trypsin, chymotrypsin and glutamic acid protease.

[0007] The present application can improve the hydrolysis degree of micellar casein in vivo by compounding micellar casein with the above-mentioned complex enzyme. Glutamic acid protease and chymosin can specifically hydrolyze micellar casein, while pepsin and trypsin are enzymes that hydrolyze proteins extensively, which can hydrolyze micellar casein and further hydrolyze the products of micellar casein hydrolysis, thereby facilitating its rapid and complete absorption and utilization and improving its nutritional value.

[0008] According to the embodiments of the present application, the composition may also have the following additional technical features: According to an embodiment of the present application, the pepsin, trypsin and chymosin are derived from cattle; the glutamate protease is derived from thermophilic fungi; and the mass ratio of the pepsin, trypsin, chymosin and glutamate protease is (1~5):(1~5):(1~3):(1~3).

[0009] According to an embodiment of the present application, the composition further includes lactose and lactase; the mass proportion of lactose in the composition is 1% to 2%.

[0010] According to an embodiment of the present application, the mass ratio of pepsin, trypsin, chymosin, glutamic protease and lactase is (1~5):(1~5):(1~3):(1~3):(1~3).

[0011] According to an embodiment of the present application, the mass of the complex enzyme is 0.1‰~1‰ of the mass of the micellar casein.

[0012] According to an embodiment of the present application, the composition is provided in the form of powder.

[0013] In another aspect of the present application, the present application provides a food. According to an embodiment of the present application, the food includes: the aforementioned composition.

[0014] In another aspect of the present application, the present application provides a method for preparing the aforementioned composition. According to an embodiment of the present application, the method comprises: mixing the micellar casein and the complex enzyme to obtain the composition.

[0015] According to an embodiment of the present application, the micellar casein is provided in the form of a micellar casein solution; the method further comprises: spray-drying the mixed solution obtained by mixing to obtain a powder of the composition.

[0016] According to an embodiment of the present application, the method for preparing the micellar casein solution includes: sequentially defatting, sterilizing, separating with a microfiltration membrane, and concentrating with a reverse osmosis membrane the raw milk to obtain a micellar casein solution; the mixing temperature is 5°C~15°C; the spray drying treatment includes an electrostatic spray drying treatment, and the electrostatic spray drying treatment satisfies at least one of the following conditions: the inlet air temperature is 100°C~140°C; the outlet air temperature is 70°C~90°C; the feed temperature is 70°C~90°C; the atomization pressure is 2.5 mPa~3.5 mPa; the electrostatic field voltage is 10 kV~15 kV; and it is carried out under an inert atmosphere.

[0017] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. DETAILED DESCRIPTION

[0018] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0019] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0020] "Scope" disclosed in the present application is limited in the form of lower limit and upper limit, and a given range is limited by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a special range. The scope limited in this way can be including end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a scope. For example, if the scope of 60-120 and 80-110 is listed for a specific parameter, it is understood that the scope of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​1 and 2 listed, and if the maximum range values ​​3,4 and 5 are listed, the following scope can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents the abbreviation of any real number combination between a and b, wherein a and b are real numbers, and the scope limited in this way can be including end values ​​a and b. For example, the numerical range "0-5" means that all real numbers between "0-5" are listed in this document, and "0-5" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0021] If not otherwise specified, all embodiments and optional embodiments of the present application can be combined with each other to form a new technical solution.

[0022] Unless otherwise specified, all technical features and optional technical features of this application can be combined with each other to form a new technical solution.

[0023] If there is no special explanation, all steps of the present application can be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0024] The present application proposes a composition, a preparation method thereof and a food, which will be described in detail below.

[0025] Composition In one aspect of the present application, the present application provides a composition. According to an embodiment of the present application, the composition comprises: micellar casein and a composite enzyme; the composite enzyme comprises pepsin, trypsin, chymotrypsin and glutamic acid protease.

[0026] Natural casein mainly exists in the form of micelles. When it enters the body, micellar casein is hydrolyzed under the low pH conditions of the stomach and the combined action of pepsin so that it can be digested and absorbed by the body. Since some hydrophobic groups and enzyme cleavage sites of micellar casein exist inside the micelles, it is difficult to hydrolyze casein, and the degree of hydrolysis is low, which affects the complete absorption and utilization of casein by the body.

[0027] For this reason, the inventor of the present application has found through a large amount of research analysis and screening that glutamic acid protease and chymotrypsin can specifically hydrolyze micellar casein, and pepsin and trypsin are enzymes for extensively hydrolyzing proteins, which can hydrolyze micellar casein, and can further hydrolyze the product after the hydrolysis of micellar casein. Pepsin, trypsin, chymotrypsin and glutamic acid protease play a synergistic effect in gastric environment and intestinal environment, can quickly and fully hydrolyze micellar casein, and the degree of hydrolysis is high, to meet the needs of the body for protein and amino acid rapid absorption. In addition, compared to edible micellar casein and complex enzyme alone, micellar casein and complex enzyme are provided in the form of composition, which helps to improve digestion level, and micellar casein can protect complex enzyme in structure, reduce enzyme loss, thereby further improving digestion level.

[0028] According to the embodiments of the present application, the pepsin, trypsin and chymotrypsin are derived from cows. Micellar casein is usually derived from cow milk. The selection of the above three enzymes derived from cows can improve the high affinity and catalytic efficiency between the enzyme and the substrate, thereby achieving faster and more thorough protein decomposition during the hydrolysis process, with a high degree of hydrolysis, while maintaining the biological activity and nutritional value of the protein, which helps to improve the body's absorption efficiency of amino acids and proteins.

[0029] According to the embodiments of the present application, the glutamic acid protease is derived from thermophilic fungi. It should be noted that, in this article, the term "thermophilic fungi" refers to fungi that grow and reproduce at higher temperatures, which can be active at temperatures above 40°C or 45°C, and some can even survive in an environment above 60°C. Thermophilic fungi can be Aspergillus fumigatus, Chaetomium, Thermohypocrea, etc.

[0030] According to an embodiment of the present application, the mass ratio of pepsin, trypsin, chymotrypsin and glutamate protease is (1-5): (1-5): (1-3): (1-3), for example (2-5): (2-5): (1.5-2.5): (1.5-2.5), (3-5): (3-5): (1.5-2.5): (1.5-2.5), (4-5): (4-5): (1.5-2.5): (1.5-2.5). Under the above ratio conditions, the four enzymes can better play a synergistic role to decompose micellar casein more quickly and thoroughly, with a high degree of hydrolysis, and promote the body's digestion and absorption.

[0031] According to an embodiment of the present application, the composition further includes lactose and lactase. In the process of extracting micellar casein from cow's milk, a small amount of lactose is usually extracted, and the intake of lactose may cause lactose intolerance or lactose allergy. In order to reduce the occurrence of this situation, lactose can be hydrolyzed by adding lactase, thereby reducing the risk of lactose intolerance and lactose allergy and improving the absorption and utilization of lactose.

[0032] According to the embodiments of the present application, the mass percentage of lactose in the composition is 1% to 2%, for example, 1%, 1.2%, 1.4%, 1.5%, 1.6%, 1.8%, and 2%. Thus, the composition can be provided with a suitable taste and nutritional ingredients, and lactose intolerance or lactose allergy caused by excessive lactose intake can be reduced to a certain extent.

[0033] According to an embodiment of the present application, the mass ratio of pepsin, trypsin, chymotrypsin, glutamic protease and lactase is (1~5): (1~5): (1~3): (1~3): (1~3), for example (2~5): (2~5): (1.5~2.5): (1.5~2.5): (1.5~2.5), (3~5): (3~5): (1.5~2.5): (1.5~2.5): (1~2), (4~5): (4~5): (1.5~2.5): (1.5~2.5): (1~2). Under the above ratio conditions, the four enzymes can better play a synergistic role to decompose micellar casein more quickly and thoroughly, and promote the body's digestion and absorption. At the same time, lactase can better decompose lactose and reduce the risk of lactose intolerance.

[0034] According to an embodiment of the present application, the mass of the composite enzyme is 0.1‰ to 1‰ of the mass of the micellar casein, for example, 0.1‰, 0.2‰, 0.3‰, 0.4‰, 0.5‰, 0.6‰, 0.7‰, 0.8‰, 0.9‰, 1‰. The amount of the composite enzyme that meets the above conditions can make the micellar casein decompose more quickly and thoroughly, and promote the body's digestion and absorption.

[0035] According to an embodiment of the present application, the composition is provided in the form of a powder. Thus, it is convenient to carry and store, reduces the loss of protein activity, prolongs the shelf life, and improves solubility. In the present application, the "composition" may also be referred to as "micellar casein powder".

[0036] food In another aspect of the present application, the present application proposes a food. According to an embodiment of the present application, the food comprises: the aforementioned composition. The food of the present application contains micellar casein and complex enzymes. Adding the complex enzymes can increase the hydrolysis degree of micellar casein in the body, which is beneficial to its rapid and complete absorption and utilization, and improves the nutritional value.

[0037] According to an embodiment of the present application, the food includes liquid dairy products, such as formula milk, yogurt, etc.; cheese; ice cream, etc.

[0038] It should be noted that the features and advantages described above for the composition are also applicable to the food and will not be described in detail here.

[0039] Method for preparing the composition In another aspect of the present application, the present application proposes a method for preparing the aforementioned composition. According to an embodiment of the present application, the method comprises: mixing the micellar casein and the complex enzyme to obtain the composition. By mixing the micellar casein with the complex enzyme, a uniform composition can be obtained, and the addition of the complex enzyme can increase the hydrolysis degree of the micellar casein in the body, which is conducive to its rapid and complete absorption and utilization, and improves the nutritional value.

[0040] According to an embodiment of the present application, the micellar casein is provided in the form of a micellar casein solution.

[0041] According to an embodiment of the present application, the method for preparing the micellar casein solution comprises: sequentially defatting, sterilizing, separating by microfiltration membrane, and concentrating by reverse osmosis membrane on raw milk to obtain a micellar casein solution. The casein with a natural micellar structure is prepared by a microfiltration membrane separation method, the purity and activity of the micellar casein are improved, and the hydrolysis efficiency is enhanced.

[0042] In some embodiments, defatting includes: defatting the raw milk by centrifugal separation, wherein the temperature is 40-60° C., the centrifugal speed is 4000-8000 rpm, and the fat content is adjusted to 0.06%.

[0043] In some embodiments, the sterilization comprises: pasteurizing the skim milk, wherein the pasteurization temperature is 70-90° C., and the pasteurization time is 15-60 s.

[0044] In some embodiments, microfiltration membrane separation includes: subjecting pasteurized skim milk to microfiltration membrane separation, wherein the separation parameters include: the pore size of the microfiltration membrane used is 0.1 μm-0.4 μm, the transmembrane pressure is 0.05 mPa-0.1 mPa, the temperature is 40-60°C, a diafiltration process is used, the volume of diafiltration water: the volume of skim milk = (1.5-0.5): 1, the concentration factor VCF is 1-3, and a micellar casein solution is obtained, the total solid content is 9-13 g / 100g, the protein content is 7-11 g / 100g, the proportion of casein in the total protein is 84%-88%, and the lactose content is 1%-3%.

[0045] In some embodiments, reverse osmosis membrane concentration includes: subjecting the micellar casein solution obtained by microfiltration membrane separation to reverse osmosis concentration, wherein the concentration parameters are: reverse osmosis membrane flow channel is 28-40 mil, concentration pressure is 2-4 mPa, and concentration temperature is 5-15 °C, to obtain micellar casein concentrate, wherein the total solid content is 23-27 g / 100g, the protein content is 17-23 g / 100g, the proportion of casein to total protein is 84-88%, and the lactose content is 2-5 g / 100g.

[0046] According to an embodiment of the present application, the mixing temperature is 5° C. to 15° C., such as 5° C., 6° C., 8° C., 10° C., 12° C., 14° C., and 15° C. Thus, the activity of the protein is maintained during the mixing process.

[0047] According to an embodiment of the present application, the spray drying process includes an electrostatic spray drying process. The inventor has found that the mixed solution containing micellar casein is spray dried under low temperature conditions, and the obtained micellar casein powder has better solubility, which is conducive to the micellar casein powder and the complex enzyme in the digestive system to fully hydrolyze. Traditional spray drying technology is usually carried out under high temperature conditions. Although this can quickly dry the material, high temperature may cause the solubility of the micellar casein powder to decrease. If the traditional spray drying equipment is set under low temperature conditions, it will be difficult to effectively form powder. Electrostatic spray drying technology converts the liquid material to be dried into fine droplets and uses hot air to quickly dry it into a powdered or granular product. By setting it to a relatively low temperature condition, a micellar casein powder with strong solubility can be obtained. In addition, the colloidal properties of casein can be used to form a natural microcapsule structure during the drying process to protect the enzyme activity and control the time when the enzymolysis reaction starts.

[0048] According to the embodiment of the present application, the air inlet temperature is 100° C. to 140° C., and the air outlet temperature is 70° C. to 90° C. Thus, by performing electrostatic spray drying under the above temperature conditions, micellar casein powder with strong solubility can be obtained.

[0049] According to an embodiment of the present application, the feed temperature is 70°C to 90°C, for example, 70°C, 72°C, 75°C, 76°C, 78°C, 80°C, 82°C, 84°C, 85°C, 86°C, 88°C, 90°C; the atomization pressure is 2.5 mPa to 3.5 mPa, for example, 2.5 mPa, 2.6 mPa, 2.8 mPa, 3.0 mPa, 3.2 mPa, 3.4 mPa, 3.5 mPa; the electrostatic field voltage is 10 kV to 15 kV; for example, 10 kV, 11 kV, 12 kV, 13 kV, 14 kV, 15 kV; and it is carried out under an inert atmosphere, and the inert atmosphere includes nitrogen and / or helium.

[0050] By carrying out electrostatic spray drying under the above conditions, micellar casein powder with strong solubility can be obtained.

[0051] It should be noted that the features and advantages described above for the composition are also applicable to the method for preparing the composition, and will not be described in detail here.

[0052] The scheme of the present application will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present application and should not be considered as limiting the scope of the present application. If no specific technology or conditions are indicated in the embodiments, the technology or conditions described in the literature in this area or the product specification are carried out. The reagents used or the instruments that do not indicate the manufacturer are all conventional products that can be obtained commercially.

[0053] Example 1 In this example, the composition was prepared according to the following method: 1. Degreasing: Raw milk is degreased by centrifugation at a temperature of 50°C and a centrifugal speed of 5000 rpm, and the fat content is adjusted to 0.06%; 2. Pasteurization: pasteurize the skim milk at a temperature of 85°C and a pasteurization time of 30 seconds; 3. Microfiltration membrane separation: The pasteurized skim milk was separated by microfiltration membrane, and the separation parameters were as follows: the pore size of the microfiltration membrane used was 0.2 μm, the transmembrane pressure was 0.075 mPa, the temperature was 50°C, the diafiltration process was used, the diafiltration water volume: skim milk volume = 1:1, the concentration factor VCF was 2, and the micellar casein solution was obtained, the total solid content was 11 g / 100g, the protein content was 9 g / 100g, the casein ratio of the total protein was 86%, and the lactose content was 1.5%; 4. Reverse osmosis membrane concentration: The micellar casein solution obtained by microfiltration membrane separation was concentrated by reverse osmosis, and the concentration parameters were: reverse osmosis membrane flow channel was 31 mil, concentration pressure was 3 mPa, and concentration temperature was 10 °C. A micellar casein concentrate was obtained, and its total solid content was 25 g / 100g, protein content was 20 g / 100g, casein accounted for 86% of total protein, and lactose content was 3 g / 100g; 5. Mixing: Add compound enzyme to the concentrated micellar casein solution, the addition amount is 0.3‰ of the micellar casein mass, the addition ratio of pepsin, trypsin, chymosin, glutamic acid protease and lactase in the compound enzyme is 5:5:2:2:1, the mixing temperature is 10 ℃, and mix thoroughly; 6. Spray drying: The micellar casein concentrate after mixing with the complex enzyme was spray dried, wherein the spray drying parameters were: nitrogen was used as the protective gas, the atomization pressure was 3 mPa, the electrostatic field pressure was 12 kV, the feed temperature was 80°C, the air inlet temperature was 120°C, and the air outlet temperature was 80°C.

[0054] Example 2 The difference between this embodiment and embodiment 1 is that Step 5: Mixing: Add compound enzyme to the concentrated micellar casein solution. The added amount is 0.45‰ of the micellar casein mass. In the compound enzyme, the addition ratio of pepsin, trypsin, chymosin, glutamic protease and lactase is 1:1:3:3:3. The mixing temperature is 15°C and the mixture is mixed thoroughly.

[0055] Step 6: spray drying: the micellar casein concentrate after mixing with the complex enzyme is spray dried, wherein the spray drying parameters are: nitrogen is used as the protective gas, the atomization pressure is 3 mPa, the electrostatic field pressure is 12 kV, the feed temperature is 70°C, the inlet air temperature is 100°C, and the outlet air temperature is 70°C.

[0056] Example 3 The difference between this embodiment and embodiment 1 is that Step 5: Mixing: Add compound enzyme to the concentrated micellar casein solution, the added amount is 0.15‰ of the micellar casein mass, and the addition ratio of pepsin, trypsin, chymosin, glutamic protease and lactase in the compound enzyme is 3:3:1:1:2. The mixing temperature is 10°C and the mixture is mixed thoroughly.

[0057] Step 6: spray drying: the micellar casein concentrate after mixing with the complex enzyme is spray dried, wherein the spray drying parameters are: nitrogen is used as the protective gas, the atomization pressure is 3 mPa, the electrostatic field pressure is 12 kV, the feed temperature is 90°C, the inlet air temperature is 140°C, and the outlet air temperature is 90°C.

[0058] Example 4 The difference between this embodiment and embodiment 1 is that the added amount of the complex enzyme is 0.08‰ of the micellar casein mass.

[0059] Example 5 The difference between this embodiment and embodiment 1 is that the added amount of the complex enzyme is 1.5‰ of the micellar casein mass.

[0060] Example 6 The difference between this embodiment and embodiment 1 is that the mass ratio of pepsin, trypsin, chymosin, glutamic acid protease and lactase is 6:0.5:0.5:4:4.

[0061] Example 7 The difference between this embodiment and embodiment 1 is that a common spray drying method is used, no electric field is applied, no protective gas is used, the inlet air temperature is 180°C, and the outlet air temperature is 100°C.

[0062] Comparative Example 1 The difference between this comparative example and Example 1 is that step 5 is not included, and the concentrated micellar casein solution obtained in step 4 is directly subjected to step 6.

[0063] Comparative Example 2 The difference between this comparative example and Example 1 is that the complex enzyme does not contain pepsin.

[0064] Comparative Example 3 The difference between this comparative example and Example 1 is that the complex enzyme does not contain trypsin.

[0065] Comparative Example 4 The difference between this comparative example and Example 1 is that the complex enzyme does not contain chymosin.

[0066] Comparative Example 5 The difference between this comparative example and Example 1 is that the complex enzyme does not contain glutamate protease.

[0067] Comparative Example 6 The difference between this comparative example and Example 1 is that glutamic acid protease is replaced by papain.

[0068] Test Case 1. The hydrolysis degree of the compositions prepared in Examples 1 to 7 and Comparative Examples 1 to 6 was detected by in vitro simulated digestion. The detection method is as follows: 1. In vitro digestion simulation experiment 1. Gastric digestion simulation part: (1) Prepare simulated gastric fluid, wherein the simulated gastric fluid formula is: NaCl 94mM, KCl 13mM, 1mM HCl to adjust pH to 5.3, add pepsin (268 U / mL), and use 1mM HCl to adjust pH to 3; (2) Simulated digestion experiment: The composition was weighed to prepare a 5% (w / w) micellar casein solution, which was mixed with simulated gastric juice in a mass ratio of 1:1. After being kept at 37°C for 2 h, the pH was adjusted to 7 with 1 mM NaOH to obtain simulated gastric digestive fluid.

[0069] 2. Small Intestine Digestion Simulation: (1) Preparation of simulated intestinal fluid: The formula of simulated intestinal fluid is: NaCl 164mM, KCl 10mM, NaHCO3 85mM, CaCl2 3mM, bile salt (ox bile) 3.1mM, add trypsin (100U / mL), and adjust the pH to 7 with 1mM NaOH; (2) Simulated digestion experiment: Weigh the simulated gastric digestive fluid, mix it with simulated intestinal fluid in a volume ratio of 1:1, add trypsin (100 U / mL), keep it at 37°C for 2 h, and then boil it in a boiling water bath for 10 min to terminate the digestion, thus obtaining the simulated intestinal digestive fluid.

[0070] (II) OPA method for detecting degree of hydrolysis: The hydrolysis degree is determined by the o-phthalaldehyde (OPA) method. The specific method is as follows: (1) Prepare OPA reagent: Dissolve 7.62 g sodium tetraborate and 200 mg sodium dodecyl sulfate in ultrapure water, add 160 mg OPA (dissolved in 4 mL ethanol) and 176 mg thiothreitol (dissolved in ultrapure water), and finally make up to 200 mL. Store in a dark place.

[0071] (2) Preparation of serine standard solution: 50 mg L-serine was dissolved in 500 mL ultrapure water (0.9516 meqv / L).

[0072] (3) Sample solution preparation: Dissolve 0.5 g of simulated intestinal digestive fluid in 100 ml of deionized water.

[0073] (4) In a light-proof condition, add 3 mL of OPA reagent and 400 μL of the test solution (serine standard solution or sample solution) into a test tube, mix for 5 s, react at room temperature for 2 min, and measure the absorbance at a wavelength of 340 nm. Serine is used as the standard solution and ultrapure water is used as the blank control.

[0074] (5) Calculate the degree of protein hydrolysis according to the following formula:

[0075] Where: DH is the degree of protein hydrolysis, %; h is the number of peptide bonds hydrolyzed in milk protein, meqv / g; h tot The total number of peptide bonds in milk protein is 8.2, meqv / g. The calculation formula for h is:

[0076] Where: serine-NH2 is the amount of serine-NH2 per gram of protein, meqv / g; β and α are constants of 0.40 and 1.00 respectively. The calculation formula of Serine-NH2 is:

[0077] Where: V is the sample volume, L; X is the sample mass, g; P is the protein content in the sample, %.

[0078] 2. The insolubility index of the compositions prepared in Examples 1 to 7 and Comparative Examples 1 to 6 was respectively measured, and the measurement was based on the national standard: GB 5413.29-2010.

[0079] 3. Results and Analysis The results are shown in Table 1. Compared with Comparative Examples 1-6, the compositions prepared in Examples 1-7 have better overall characteristics. The hydrolysis of micellar casein can be effectively improved by the combined action of pepsin, trypsin, chymotrypsin and glutamic acid protease.

[0080] It can be seen from Example 1 and Example 7 that the low-temperature electrostatic spray drying treatment helps to maintain the enzymatic activity of the enzyme, thereby better enzymatically hydrolyzing the micellar casein and improving the solubility of the composition.

[0081] Table 1 Hydrolysis degree and solubility

[0082] Although the embodiments of the present application have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations on the present application. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present application.

Claims

1. A composition, characterized in that include: Micellar casein and enzyme complex; The complex enzyme comprises pepsin, trypsin, chymotrypsin and glutamic acid protease.

2. The composition according to claim 1, characterized in that The pepsin, trypsin and chymotrypsin are derived from cattle; The glutamate protease is derived from a thermophilic fungus; The mass ratio of pepsin, trypsin, chymosin and glutamic acid protease is (1-5): (1-5): (1-3): (1-3).

3. The composition according to claim 1, characterized in that The composition further comprises lactose and lactase; The mass proportion of lactose in the composition is 1% to 2%.

4. The composition according to claim 3, characterized in that The mass ratio of pepsin, trypsin, chymosin, glutamic acid protease and lactase is (1-5): (1-5): (1-3): (1-3): (1-3).

5. The composition according to claim 1, characterized in that The mass of the complex enzyme is 0.1‰ to 1‰ of the mass of the micellar casein.

6. The composition according to any one of claims 1 to 5, characterized in that The composition is provided in the form of a powder.

7. A food, characterized in that include: The composition according to any one of claims 1 to 6.

8. A method for preparing the composition according to any one of claims 1 to 6, characterized in that: include: The micellar casein and the complex enzyme are mixed to obtain the composition.

9. The method according to claim 8, characterized in that The micellar casein is provided in the form of a micellar casein solution; The method further comprises: spray drying the mixed solution obtained by mixing to obtain a powder of the composition.

10. The method according to claim 9, characterized in that The preparation method of the micellar casein solution comprises: sequentially performing defatting, sterilization, microfiltration membrane separation, and reverse osmosis membrane concentration on raw milk to obtain a micellar casein solution; The mixing temperature is 5°C to 15°C; The spray drying process includes electrostatic spray drying process; The electrostatic spray drying process satisfies at least one of the following conditions: The air inlet temperature is 100℃~140℃; The air outlet temperature is 70℃~90℃; Feed temperature is 70℃~90℃; Atomization pressure is 2.5 mPa~3.5 mPa; The electrostatic field voltage is 10 kV~15 kV; Carry out under inert atmosphere.

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