ACE (Angiotensin Converting Enzyme) inhibitory decapeptide IR10 derived from cattle cheese protein hydrolysate and application thereof

Abstract

The invention discloses ACE (Angiotensin Converting Enzyme) inhibitory decapeptide IR10 derived from bovine cheese protein hydrolysate and application of the ACE inhibitory decapeptide IR10, and relates to the technical field of bioactive peptides, and the technical scheme of the ACE inhibitory decapeptide IR10 is characterized in that the amino acid sequence is IQKEDVPSER. The ACE inhibitory decapeptide IR10 derived from the cattle cheese protein hydrolysate is obtained by screening from the cattle cheese protein hydrolysate and is decapeptide IR10 with ACE inhibitory activity, the in-vitro ACE inhibition rate of the ACE inhibitory decapeptide IR10 derived from the cattle cheese protein hydrolysate is tested to be 62.07% under the condition of the concentration of 1mg / ml, and the ACE inhibitory decapeptide IR10 has the effect of being suitable for functional food for assisting blood pressure reduction.

Description

Technical Field

[0001] The present invention relates to the technical field of bioactive peptides, and more specifically to an ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate and application thereof. Background Art

[0002] Angiotensin converting enzyme inhibitors (ACEI) have a hypotensive effect. There are reports on the preparation of ACE inhibitory peptides by enzymatic hydrolysis of protein raw materials from plants, animals and microorganisms (Wang Jing, Wang Lixia, Ren Caixia, et al. Research progress on the preparation method and mechanism of action of food-derived ACE inhibitory peptides. Chinese Food and Nutrition, 1-9 [2025-01-06]). Using different proteins as raw materials and different enzymatic hydrolysis processes to prepare ACE inhibitory peptides, the composition of active peptides in the obtained enzymatic hydrolysates is very different. It is very difficult to obtain monomeric active peptides with ACE inhibitory activity from complex enzymatic hydrolysates.

[0003] The Chinese invention patent with the patent number ZL200480022213.9 discloses a casein hydrolysate and its production process and application. The casein hydrolysate and its production process and application disclose the use of Aspergillus oryzae extracellular enzyme group to hydrolyze casein to prepare a protease hydrolysate with ACE inhibition rate, and report that IPP and VPP are the core ACE inhibitory peptide components. Yang Zhiyu et al. reported the process of preparing ACE inhibitory peptides by hydrolyzing Flammulina velutipes with trypsin and ultrasound in the article "Response Surface Optimization of Ultrasonic-Assisted Enzymatic Hydrolysis Method for Preparation of Flammulina velutipes ACE Inhibitory Peptides"; Qin Ying et al. reported the process of preparing ACE inhibitory peptides by enzymatic hydrolysis of white shrimp heads with compound enzymes (trypsin: flavor protease) in "Process Optimization of Preparation of ACE Inhibitory Peptides by Compound Enzymatic Hydrolysis of White Shrimp Heads"; Zhang Man et al. reported the process of preparing ACE inhibitory peptides by hydrolyzing wheat protein with alkaline protease in "Preparation of Wheat ACE Inhibitory Peptides by Ultrasonic-Assisted Enzymatic Hydrolysis Method and Study of Its Stability". However, the above studies are basically carried out around protease hydrolysate mixtures, and the peptide sequences with ACE inhibitory activity and their ACE inhibitory activity are unclear.

[0004] Zhao Feiran et al. screened out 7 tetrapeptides from traditional fermented soy products with high ACE inhibitory potential in "Study on the Structure-Activity Relationship of ACE Inhibitory Tetrapeptides in Traditional Fermented Soy Products"; Yang Zeyao et al. identified the bovine bone peptide GPSGPR with ACE inhibitory activity in "Identification and Characterization of Bovine Bone-Derived ACE Inhibitory Peptides", with IC50 = 382.16 μmol / L. Nie Peng et al. obtained five active peptides in the article "Isolation, Identification and Activity Evaluation of ACE Inhibitory Peptides from Monocypris monocypris", namely Pro-Gln-Met-Thr-Phe, Pro-Tyr-Phe-Lys-His, Pro-Gly-Trp-Lys-Ala, Pro-Gln-Gly-Met-Ile-Val-Val, and Val-Met-Arg-Ile-Il; the first, fourth and fifth peptides showed good ACE inhibitory activity, with inhibition rates of 86.26±0.85%, 92.11±1.13%, and 96.51±1.04%, respectively. Martin M et al. further listed the active peptide structures with ACE inhibitory function derived from protease hydrolysate discovered in recent years in the article "Effects of natural peptides from food proteins on angiotensin converting enzyme activity and hypertension".

[0005] However, the enzymatic hydrolysis strategies adopted in the above-mentioned prior art are based on different enzymatic hydrolysis strategies, which will have a huge impact on the functional activity of the hydrolyzate and the sequence composition and abundance of active peptides in the hydrolyzate, and none of them can be used to obtain functional foods for assisting in lowering blood pressure, and needs to be improved. Summary of the invention

[0006] In view of this, the first object of the present application is to provide an ACE inhibitory decapeptide I R10 derived from cow cheese protein hydrolysate, so as to achieve the purpose of being suitable for functional food for assisting in lowering blood pressure. The specific scheme is as follows:

[0007] An ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate, whose amino acid sequence is IQKEDVPSER.

[0008] Preferably: its molecular weight is 1200.29 Da.

[0009] Preferably, it is selected from cow cheese protein hydrolysate.

[0010] Preferably: the method for preparing the cow cheese protein hydrolysate comprises the following steps:

[0011] Step 1, taking cow casein, adding casein in an amount of 1-5%, pH 8-9, adding 2-6% protease, performing enzymolysis, controlling the enzymolysis temperature at 37-55°C, and the enzymolysis time at 4-6h, to obtain an enzymolysis product;

[0012] Step 2, preliminarily filtering the enzymatic hydrolysate to remove the residue to obtain a clarified polypeptide enzymatic hydrolysate, and freeze-drying to obtain polypeptide freeze-dried powder;

[0013] Step 3, the polypeptide freeze-dried powder is subjected to mass spectrometry analysis by LC-MS / MS, and the results of the mass spectrometry analysis are analyzed by mass spectrometry analysis software, and compared with the milk casein sequence to obtain nonapeptide and decapeptide sequences;

[0014] Step 4: Molecular docking of the nonapeptide and decapeptide sequences with the ACE protein. Before docking, the 2D structure of the peptide is converted into a 3D structure by energy minimization, and a peptide sequence with strong binding ability to the ACE protein is screened;

[0015] Step 5: Solid phase synthesize the screened polypeptide sequence, and use an in vitro ACE enzyme activity inhibition test to obtain a decapeptide I R10 with ACE inhibitory activity.

[0016] Preferably: in step 1, the amount of milk casein added is 2%; the amount of mixed protease added is 5%, and the protease is composed of trypsin and enzyme group X in a mixing ratio of 3:1, the enzymolysis temperature is controlled at 37°C, the pH value is 8.0, and the enzymolysis time is 6h.

[0017] Preferably: in step 3, the mass spectrometry conditions are controlled as follows: in the liquid phase method, the chromatographic column is C18, 3μm, 250mmX75μm, Eks igent, phase A is water, 0.1% formic acid; phase B is acetonitrile, 0.1% formic acid, the flow rate is 300n l / min, the injection volume is 4μl, 60min chromatographic gradient, and the elution gradient is: 0-48min: phase A is uniformly reduced from 95% to 60%; 48-55min: phase A is uniformly reduced from 60% to 30%; 55-56min: phase A is uniformly reduced from 30% to 0; 56-60min: maintain 0% phase A.

[0018] Preferably: in the mass spectrometry, the equipment model used is: Orbitrap Exploris480-Thermofisher, based on the positive ion detection mode, and the following parameters are controlled for measurement: the primary resolution is 120000, the AGC is set to 300, the scanning range is 200-1600m / z, the MIPS mode is peptide, the valence state 1-5 is selected, the secondary resolution is 15000, and the separation window is 1.6m / z.

[0019] Preferably: in step 5, the in vitro ACE enzyme activity inhibition test is based on testing the in vitro ACE activity inhibition effect of the active peptide at a concentration of 1 mg / ml.

[0020] The second object of the present invention is to provide an application of ACE-inhibiting decapeptide I R10 derived from cow case protein hydrolysate, comprising using the ACE-inhibiting decapeptide I R10 derived from cow case protein hydrolysate as described above and applying it to functional foods that assist in lowering blood pressure.

[0021] Preferably: the functional food for assisting in lowering blood pressure has an in vitro ACE inhibition rate of 62.07% under the condition of a concentration of 1 mg / ml.

[0022] From the above scheme, it can be known that the present application provides an ACE-inhibiting decapeptide IR10 derived from cow case protein hydrolysate and its application. The ACE-inhibiting decapeptide IR10 derived from cow case protein hydrolysate is screened from cow case protein hydrolysate and is a decapeptide IR10 with ACE inhibitory activity. Based on the condition of a concentration of 1 mg / ml, the test results show that the in vitro ACE inhibition rate of the ACE-inhibiting decapeptide IR10 derived from cow case protein hydrolysate is 62.07%, which is suitable for functional foods to assist in lowering blood pressure, thereby achieving significant blood pressure lowering therapeutic effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic diagram of the 3D molecular docking map of I R10 and ACE of the present application;

[0024] Figure 2 yes Figure 1 A local enlarged schematic diagram in FIG.

[0025] Figure 3 is a schematic diagram of the 2D molecular docking map of I R10 and ACE of the present application;

[0026] Figure 4 is a schematic diagram of the 3D molecular docking map of QE10 and ACE of the present application;

[0027] Figure 5 yes Figure 4 A local enlarged schematic diagram in FIG.

[0028] Figure 6 is a schematic diagram of the 2D molecular docking map of QE10 and ACE of the present application;

[0029] Figure 7 This is a comparison chart of the ACE inhibition rates of IR10, QE10 and AmealPeptide of the present application. DETAILED DESCRIPTION

[0030] In order to make the technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present application.

[0031] The following is a detailed description of an ACE-inhibiting decapeptide I R10 derived from cow cheese protein hydrolysate and its application in the present application.

[0032] An ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate, with an amino acid sequence of IQKEDVPSER and a molecular weight of 1200.29 Da.

[0033] In order to obtain the ACE inhibitory decapeptide I R10 derived from cow casea protein hydrolysate, it was screened from cow casea protein hydrolysate.

[0034] It should be noted that the method for preparing the cow cheese protein hydrolysate in the embodiment of the present application comprises the following steps:

[0035] Step 1, taking cow casein, adding casein in an amount of 1-5%, pH 8-9, adding 2-6% protease, performing enzymolysis, controlling the enzymolysis temperature at 37-55°C, and the enzymolysis time at 4-6h, to obtain an enzymolysis product;

[0036] Step 2, preliminarily filtering the enzymatic hydrolysate to remove the residue to obtain a clarified polypeptide enzymatic hydrolysate, and freeze-drying to obtain polypeptide freeze-dried powder;

[0037] Step 3, the polypeptide lyophilized powder is subjected to mass spectrometry determination by LC-MS / MS, the results of the mass spectrometry determination are analyzed by mass spectrometry analysis software, and compared with the milk casein sequence to obtain nonapeptide and decapeptide sequences; wherein, the mass spectrometry determination conditions are controlled as follows: the chromatographic column in the liquid phase method is C18, 3μm, 250mmX75μm, Eksigent, phase A is water, 0.1% formic acid; phase B is acetonitrile, 0.1% formic acid, the flow rate is 300nl / min, the injection volume is 4μl, 60min chromatographic gradient, and the elution gradient is: 0-48min: phase A is uniformly reduced from 95% to 60%; 48-55min: phase A is uniformly reduced from 60% to 30%; 55-56min: phase A is uniformly reduced from 30% to 0; 56-60min: maintain 0% phase A. In the mass spectrometry measurement, the equipment model used was: OrbitrapExploris480-Thermofisher, based on the positive ion detection mode, and the following parameters were controlled for measurement: primary resolution was 120000, AGC was set to 300, scanning range was 200-1600m / z, MIPS mode was peptide, valence states 1-5 were selected, secondary resolution was 15000, and separation window was 1.6m / z.

[0038] Step 4: Molecular docking of the nonapeptide and decapeptide sequences with the ACE protein. Before docking, the 2D structure of the peptide is converted into a 3D structure by energy minimization, and a peptide sequence with strong binding ability to the ACE protein is screened;

[0039] Step 5: Solid phase synthesize the screened polypeptide sequence, and use the in vitro ACE enzyme activity inhibition test to test the in vitro ACE activity inhibition effect of the active peptide based on a concentration of 1 mg / ml to obtain the decapeptide IR10 with ACE inhibitory activity.

[0040] In order to further increase the content of ACE-inhibiting decapeptide IR10 derived from bovine casein protein hydrolysate in bovine casein protein hydrolysate to reduce the difficulty of screening, in step 1 of the embodiment of the present application, the amount of bovine casein added is 2%; the amount of mixed protease added is 5%, and the protease is composed of trypsin and enzyme group X in a mixing ratio of 3:1, the enzymatic hydrolysis temperature is controlled at 37°C, the pH value is 8.0, and the enzymatic hydrolysis time is 6h.

[0041] An application of ACE-inhibiting decapeptide I R10 derived from cow cheese protein hydrolysate, comprising using the above-mentioned ACE-inhibiting decapeptide I R10 derived from cow cheese protein hydrolysate and applying it to a functional food for assisting in lowering blood pressure. The functional food for assisting in lowering blood pressure has an in vitro ACE inhibition rate of 62.07% under a concentration condition of 1 mg / ml.

[0042] Embodiment 1

[0043] An ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate, with an amino acid sequence of IQKEDVPSER and a molecular weight of 1200.29 Da.

[0044] In order to obtain the ACE inhibitory decapeptide I R10 derived from cow casea protein hydrolysate, it was screened from cow casea protein hydrolysate.

[0045] It should be noted that the method for preparing the cow cheese protein hydrolysate in the embodiment of the present application comprises the following steps:

[0046] Step 1, taking cow casein, adding 2% casein, pH 8.0, adding 5% protease (trypsin: enzyme group X = 3:1) for enzymolysis, controlling the enzymolysis temperature at 37°C, and the enzymolysis time for 6 hours to obtain an enzymolysis product;

[0047] Step 2, preliminarily filtering the enzymatic hydrolysate to remove the residue to obtain a clarified polypeptide enzymatic hydrolysate, and freeze-drying to obtain polypeptide freeze-dried powder;

[0048] Step 3, the polypeptide lyophilized powder was subjected to mass spectrometry analysis by LC-MS / MS, the results of the mass spectrometry analysis were analyzed by mass spectrometry analysis software, and compared with the milk casein sequence to obtain the nonapeptide and decapeptide sequences; the LC-MS / MS measurement conditions were as follows: in the liquid phase method, the chromatographic column was C18, 3 μm, 250 mm × 75 μm (Eksigent), phase A was water, 0.1% formic acid; phase B was acetonitrile, 0.1% formic acid, the flow rate was 300 nl / min, the injection volume was 4 μl, and the chromatographic gradient was 60 min, and the specific elution gradient was as follows: 0-48 min: phase A was uniformly reduced from 95% to 60%; 48-55 min: phase A was uniformly reduced from 60% to 30%; 55-56 min: phase A was uniformly reduced from 30% to 0; 56-60 min: maintain 0% phase A. Mass spectrometry method: Orbitrap Exploris 480-Thermofisher, positive ion detection mode, primary resolution of 120000, AGC setting of 300, scanning range of 200-1600 m / z. MIPS mode of peptide, valence state 1-5, secondary resolution of 15000, separation window of 1.6 m / z.

[0049] As shown in Table 1 , 32 high-abundance active nonapeptide and decapeptide sequences were finally obtained.

[0050] Table 1. Sequences of highly abundant active peptides in milk cheese protein hydrolysate

[0051]

[0052]

[0053] Step 4: Molecular docking of the nonapeptide and decapeptide sequences with the ACE protein. Before docking, the 2D structure of the peptide was converted to a 3D structure by energy minimization, and the peptide sequence with strong binding ability to the ACE protein was screened. The 3D structure of ACE can be downloaded from the RCSB protein database (PDB ID: 1O8A). The results of molecular docking are shown in Table 2 below. The docking results are expressed in -Ci E. The larger the -Ci E value, the stronger the ability of the peptide to bind to ACE, and the more likely it is to inhibit ACE activity.

[0054] Table 2. Prediction results of the interaction between milk casein components and ACE

[0055]

[0056]

[0057] Step 5, the screened polypeptide sequence was solid-phase synthesized, and the in vitro ACE activity inhibition effect of the active peptide was tested based on a concentration of 1 mg / ml using an in vitro ACE enzyme activity inhibition test to obtain a decapeptide IR10 with ACE inhibitory activity. Among all the tested active peptides, QGLPQEVLNE (QE10) had the largest docking score (171.437), followed by IQKEDVPSER (IR10) (164.393). The peak areas of the above two active peptides were 1.97E+08 and 7.17E+07, respectively.

[0058] Based on the obtained QE10 and I R10, the binding modes are as follows in the tests after molecular docking and solid phase synthesis: Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 Based on the above Figures 1 to 6 , the following Table 3 is obtained after sorting, from which it can be concluded that IR10 forms 11 HH bond interactions, 6 CH bond interactions, and 2 salt bridges with 38 amino acid residues involved in the interaction between the two. QE10 forms 5 HH bond interactions, 2 CH bond interactions, and 3 salt bridges with ACE, and 35 amino acid residues involved in the interaction between QE10 and ACE.

[0059] Table 3. Molecular docking parameters of IR10 and QE10 with ACE

[0060]

[0061] In Example 1 of the present application, the specific method for testing the inhibitory effect of ACE activity in vitro is as follows:

[0062] The test method is as follows: both the sample and the hydrolyzed sample are diluted 9 times with distilled water to a final concentration of 1 mg / ml. 0.1mM boric acid-borax buffer: weigh 12.37g of boric acid and dilute to 1000mL with distilled water. Weigh 19.07g of sodium tetraborate and dilute to 1000mL with distilled water. Take 175mL of sodium tetraborate solution and 325mL of boric acid solution, adjust the pH to 8.3 with hydrochloric acid or sodium oxide, and finally add 17.532g of sodium chloride, dissolve and dilute to 1000mL. 5mM HHL solution: weigh 2mg of HHL and dissolve in 920μL of 0.1mol / L borate buffer (pH8.3) containing 0.3mol / L sodium chloride. 0.1U / mL ACE solution: The whole bottle of ACE contains 0.25U, which is dissolved in 125μL of 0.01M potassium phosphate buffer (pH7.0) containing 0.5M sodium chloride, stored at -20℃, and diluted 20 times with 0.1M borate buffer (pH8.3) containing 0.3M sodium chloride before use. 1M hydrochloric acid solution: Slowly add 9mL of hydrochloric acid along the wall of 100mL of distilled water. 1mg / mL hippuric acid standard solution: Weigh 10mg of hippuric acid and dilute to 10mL with distilled water. When using, dilute with distilled water to 0.2, 0.4, 0.6, 0.8 and 1.0mg / mL standard solutions.

[0063] Reaction conditions: Take a 2mL centrifuge tube, add 80μL HHL solution (5mM) and 20μL sample, shake and mix thoroughly, keep warm at 37℃ for 5min, then add 20μL ACE solution (0.1U / mL), mix and keep warm at 37℃ for 30min. Add 200μL 1M hydrochloric acid solution to terminate the reaction. Filter with 0.22μm filter membrane and use HPLC to determine the content of hippuric acid. In the control experiment, use 20μL distilled water instead of sample.

[0064] Liquid phase conditions: Chromatographic column: Agilent ZORBAX SB-C18 chromatographic column (4.6×250mm, 5μm). Mobile phase: acetonitrile and water volume ratio of 25:75, wherein 0.05% trifluoroacetic acid was added to the water phase. Detection parameters: Column oven temperature 30°C, injection volume 20μL, flow rate 0.5mL / min, detection wavelength 228nm.

[0065] The calculation formula of ACE inhibition rate is: ACE inhibition rate (%) = (BA) x 100 / B, wherein A is the hippuric acid concentration in the sample; B is the hippuric acid concentration in the blank control.

[0066] Finally, if Figure 7 As shown, at a concentration of 1 mg / ml, the in vitro ACE inhibition rate of IR10 was 62.07%, at the same concentration, the in vitro ACE inhibition rate of QE10 was 5.01%, and the in vitro ACE inhibition rate of Anyiru polypeptide was 54.36%.

[0067] An application of ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate, comprising using the above-mentioned ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate and applying it to a functional food for assisting in lowering blood pressure. The functional food for assisting in lowering blood pressure has an in vitro ACE inhibition rate of 62.07% under a concentration condition of 1 mg / ml.

[0068] Embodiment 2

[0069] The difference between Example 2 and Example 1 is that in step 1 of Example 2, the casein addition amount is 1%, the pH is 8.5, 2% protease is added, enzymolysis is performed, the enzymolysis temperature is controlled at 45° C., the enzymolysis time is 4 hours, and an enzymolysis product is obtained.

[0070] Embodiment 3

[0071] The difference between Example 3 and Example 1 is that in step 1 of Example 3, the casein addition amount is 5%, pH is 9, 6% protease is added for enzymolysis, the enzymolysis temperature is controlled at 55° C., the enzymolysis time is 6 hours, and an enzymolysis product is obtained.

[0072] In summary, the present application provides an ACE inhibitory decapeptide IR10 derived from cow case protein hydrolysate and its application. The ACE inhibitory decapeptide IR10 derived from cow case protein hydrolysate is screened from cow case protein hydrolysate and is a decapeptide IR10 with ACE inhibitory activity. Based on the condition of a concentration of 1 mg / ml, the test results show that the in vitro ACE inhibition rate of the ACE inhibitory decapeptide IR10 derived from cow case protein hydrolysate is 62.07%, which is suitable for functional foods to assist in lowering blood pressure, thereby achieving significant blood pressure lowering therapeutic effects.

[0073] The "first", "second", "third", "fourth", etc. (if any) referred to in this application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods or devices.

[0074] It should be noted that the descriptions involving "first", "second", etc. in this application are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0075] Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

Claims

1. An ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate, characterized in that: Its amino acid sequence is IQKEDVPSER.

2. The ACE-inhibiting decapeptide IR10 derived from cow cheese protease hydrolysate according to claim 1, characterized in that: Its molecular weight is 1200.29 Da.

3. The ACE-inhibiting decapeptide IR10 derived from cow cheese protease hydrolysate according to claim 1, characterized in that: It is screened from cow cheese protein hydrolysate.

4. The ACE-inhibiting decapeptide IR10 derived from cow cheese protease hydrolysate according to claim 3, characterized in that: The method for preparing the cow cheese protein hydrolysate comprises the following steps: Step 1: Take cow casein, add 1-5% casein, pH 8-9, add 2-6% protease, perform enzymolysis, control the enzymolysis temperature at 37-55°C, and the enzymolysis time at 4-6h to obtain an enzymolysis product; Step 2, preliminarily filtering the enzymatic hydrolysate to remove the residue to obtain a clarified polypeptide enzymatic hydrolysate, and freeze-drying to obtain polypeptide freeze-dried powder; Step 3, the polypeptide freeze-dried powder is subjected to mass spectrometry analysis by LC-MS / MS, and the results of the mass spectrometry analysis are analyzed by mass spectrometry analysis software, and compared with the milk casein sequence to obtain nonapeptide and decapeptide sequences; Step 4: Molecular docking of the nonapeptide and decapeptide sequences with the ACE protein. Before docking, the 2D structure of the peptide is converted into a 3D structure by energy minimization, and a peptide sequence with strong binding ability to the ACE protein is screened; Step 5: Solid phase synthesize the screened polypeptide sequence, and use an in vitro ACE enzyme activity inhibition test to obtain the decapeptide IR10 with ACE inhibitory activity.

5. The ACE-inhibiting decapeptide IR10 derived from cow cheese protease hydrolysate according to claim 4, characterized in that: In step 1, the added amount of milk casein is 2%; the added amount of the mixed protease is 5%, and the protease is composed of trypsin and enzyme group X in a mixing ratio of 3:1, the enzymatic hydrolysis temperature is controlled at 37°C, the pH value is 8.0, and the enzymatic hydrolysis time is 6h.

6. The ACE-inhibiting decapeptide IR10 derived from cow cheese protease hydrolysate according to claim 4, characterized in that: In step 3, the mass spectrometry conditions are controlled as follows: in the liquid phase method, the chromatographic column is C18, 3μm, 250mmX75μm, Eksigent, phase A is water, 0.1% formic acid; phase B is acetonitrile, 0.1% formic acid, the flow rate is 300nl / min, the injection volume is 4μl, the chromatographic gradient is 60min, and the elution gradient is: 0-48min: phase A is uniformly reduced from 95% to 60%; 48-55min: phase A is uniformly reduced from 60% to 30%; 55-56min: phase A is uniformly reduced from 30% to 0; 56-60min: maintain 0% phase A.

7. The ACE-inhibiting decapeptide IR10 derived from cow cheese protease hydrolysate according to claim 6, characterized in that: In the mass spectrometry, the device model used is: Orbitrap Exploris480-Thermofisher, based on the positive ion detection mode, and the following parameters are controlled for measurement: the primary resolution is 120000, the AGC is set to 300, the scanning range is 200-1600m / z, the MIPS mode is peptide, the valence state 1-5 is selected, the secondary resolution is 15000, and the separation window is 1.6m / z.

8. The ACE-inhibiting decapeptide IR10 derived from cow cheese protease hydrolysate according to claim 4, characterized in that: In step 5, the in vitro ACE enzyme activity inhibition test is based on testing the in vitro ACE activity inhibition effect of the active peptide at a concentration of 1 mg / ml.

9. An application of ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate, characterized in that: The method comprises using the ACE-inhibiting decapeptide IR10 derived from cow cheese protein hydrolysate as described in any one of claims 1 to 8 and applying it to functional food for assisting in lowering blood pressure.

10. The use of the ACE-inhibiting decapeptide IR10 derived from cow cheese protease hydrolysate according to claim 9, characterized in that: The functional food for assisting in lowering blood pressure has an in vitro ACE inhibition rate of 62.07% under the condition of a concentration of 1 mg / ml.

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