Method for preparing donkey-hide gelatin oligopeptide by adopting dynamic bionic digestive system

Abstract

The invention relates to a method for preparing colla corii asini oligopeptide by adopting a dynamic bionic digestive system, which comprises the following steps: preparing digestive juice simulation liquid which comprises oral cavity digestive juice, stomach digestive juice and intestinal digestive juice; the donkey-hide gelatin peptide sample simulates oral digestion; starting a dynamic human body bionic digestion system, adding a sample digested by an oral cavity into the system, adding gastrointestinal digestion liquid into the system, and simulating a dynamic gastrointestinal digestion process; collecting gastrointestinal digestion products, carrying out water bath enzyme deactivation, cooling, centrifuging, separating supernate and precipitate, and detecting molecular weight distribution of the supernate; and freeze-drying the supernate into powder to obtain the donkey-hide gelatin oligopeptide. The colla corii asini peptide is treated by adopting a dynamic bionic digestive system, the digestion process of a human body is simulated, and the colla corii asini oligopeptide is obtained, so that blood-enriching active substances in the colla corii asini peptide are better released, human body absorption is facilitated, and the bioavailability and the blood-enriching effect of the colla corii asini peptide are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of food, and in particular to a method for preparing colla corii asini oligopeptides by using a dynamic bionic digestive system. Background Art

[0002] In recent years, with the pursuit of a healthy lifestyle by people, natural nutritional supplements have attracted much attention. As a traditional Chinese medicine, colla corii asini has the effects of enriching blood, beautifying the face, nourishing yin and moistening dryness, and is widely popular. Although colla corii asini itself is an excellent product for tonifying qi and blood, due to its relatively large molecular weight, the absorption efficiency by the human body is relatively low.

[0003] Colla corii asini peptides are obtained by enzymatic hydrolysis of colla corii asini. Their molecular weight is small and they are more easily absorbed and utilized by the human body. Although enzymatic hydrolysis technology can obtain colla corii asini peptides, the activities of different enzymes may be different in the same environment, and the enzymatic hydrolysis effects on the components in colla corii asini will also vary. If the enzymatic hydrolysis is not sufficient, it may lead to that some components of colla corii asini fail to be effectively converted into low-molecular-weight colla corii asini peptides, thus affecting the quality and effect of colla corii asini peptides. In addition, although enzymatic hydrolysis can obtain low-molecular-weight colla corii asini peptides, it often has a large gap with the human digestive process. Therefore, how to obtain colla corii asini oligopeptides that are more conducive to human absorption is the focus and difficulty of current research.

[0004] In view of this, the present invention is specifically proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing colla corii asini oligopeptides by using a dynamic bionic digestive system, which can simulate the human digestive process to obtain colla corii asini oligopeptides, so as to better release the blood-enriching active substances in colla corii asini peptides, be conducive to human absorption, and improve the bioavailability and blood-enriching effect of colla corii asini peptides.

[0006] In the first aspect of the present invention, a method for preparing colla corii asini oligopeptides by using a dynamic bionic digestive system is provided, including the following steps:

[0007] S1, preparing a digestive juice simulation solution, which includes: oral digestive juice, gastric digestive juice and intestinal digestive juice;

[0008] S2, simulating oral digestion of the colla corii asini peptide sample;

[0009] S3, starting the dynamic human bionic digestive system, preheating and then adding the colla corii asini peptide into the system, and then gradually quantitatively adding the gastric digestive juice and intestinal digestive juice into the system to simulate the dynamic gastrointestinal digestion process;

[0010] S4, collecting the gastrointestinal digestion products, inactivating enzymes in a water bath, cooling and then centrifuging, separating the supernatant, and detecting the molecular weight distribution of the supernatant;

[0011] S5, after the detection is completed, freeze-drying the supernatant into a powder to obtain colla corii asini oligopeptides.

[0012] Preferably, the method further comprises the following steps:

[0013] S6. Detect the anemia-improving efficacy of the obtained colla corii asini oligopeptide. The indexes for detecting the anemia-improving efficacy include: the staining intensity of red blood cells in the heart and the hemoglobin content. The blood-tonifying effect is comprehensively evaluated through these two indexes, which improves the accuracy and reliability of the evaluation.

[0014] Preferably, in the detection of the anemia-improving efficacy, a zebrafish anemia model is established by using phenylhydrazine. The advantage of the zebrafish anemia model is high-throughput and intuitive, which can quickly and accurately evaluate the blood-tonifying effect of colla corii asini peptide, improve the evaluation efficiency, and contribute to promoting the application and development of colla corii asini peptide in the field of biomedicine.

[0015] In the present invention, the digestive juice simulation solution can be flexibly prepared according to the components of digestive juices of different age groups (infants, adults, the elderly, etc.), so as to obtain low-molecular-weight colla corii asini peptides suitable for different age groups.

[0016] Preferably, in step S1, the oral digestive juice is prepared from KCl, NaHCO3, KH2PO4, (NH4)2CO3, MgCl2(H2O)6, CaCl2(H2O)2, α-amylase, and HCl as raw materials; the gastric digestive juice is prepared from NaCl, KCl, NaHCO3, KH2PO4, (NH4)2CO3, MgCl2(H2O)6, CaCl2(H2O)2, pepsin, and HCl as raw materials; the intestinal digestive juice is prepared from NaCl, KCl, NaHCO3, KH2PO4, MgCl2(H2O)6, CaCl2(H2O)2, pancreatin, bile salts, and HCl as raw materials.

[0017] Preferably, the oral digestive fluid includes: 14 - 16 mM KCl, 12 - 14 mM NaHCO3, 3 - 4 mM KH2PO4, 0.04 - 0.08 mM (NH4)2CO3, 0.1 - 0.2 mM MgCl2(H2O)6, 1 - 2 mM CaCl2(H2O)2, 5 - 200 U / ml α-amylase, with a pH value of 6.5 - 7.5; the gastric digestive fluid includes: 46 - 48 mM NaCl, 6 - 8 mM KCl, 24 - 26 mM NaHCO3, 0.5 - 1.5 mM KH2PO4, 0.4 - 0.6 mM (NH4)2CO3, 0.08 - 0.15 mM MgCl2(H2O)6, 0.1 - 0.2 mM CaCl2(H2O)2, 100 - 4000 U / ml pepsin, with a pH value of 1 - 3; the intestinal digestive fluid includes: 37 - 39 mM NaCl, 6 - 8 mM KCl, 83 - 85 mM NaHCO3, 0.5 - 1 mM KH2PO4, 0.2 - 0.5 mM MgCl2(H2O)6, 0.5 - 0.8 mM CaCl2(H2O)2, 0.1 - 6 USP / ml trypsin, 5 - 25 mM bile salts, with a pH value of 6.5 - 7.5.

[0018] In the present invention, when preparing the simulated solutions of oral, gastric and intestinal digestive fluids, they are strictly formulated according to the characteristics of human physiological conditions. At the same time, the preparation of each digestive fluid is based on the active concentration of digestive enzymes, abandoning the traditional method of only using the weight of digestive enzyme reagents as the preparation standard, thereby avoiding affecting the quality and effect of ejiao peptides due to differences between batches of digestive enzymes.

[0019] Preferably, step S2 includes: placing the ejiao peptide, water and oral digestive fluid in a water bath at 37°C, and stirring them in the water bath to simulate oral digestion.

[0020] Preferably, the mass ratio of the ejiao peptide, water and oral digestive fluid is (2 - 3):(12 - 18):(2 - 3).

[0021] Preferably, step S3 includes: starting the dynamic human bionic digestive system, preheating it to 37°C, pre-adding a certain amount of gastric digestive fluid into the system, then adding the ejiao peptide after oral digestion treatment into the bionic esophagus of the system, and continuously and slowly pumping the gastric digestive fluid and intestinal digestive fluid into the gastric model and intestinal model of the system at a flow rate according to the preset parameters to fully simulate the dynamic gastrointestinal digestion process of the human body digesting food.

[0022] In a specific embodiment, the dynamic human bionic digestive system is the dynamic bionic gastrointestinal digestion equipment, DHSI-IV, produced by Xiaodong Yijian (Suzhou) Instrument and Equipment Co., Ltd.

[0023] Preferably, in step S3, the parameters of the dynamic human bionic digestive system are set as follows: temperature: 37 °C; gastric peristalsis frequency: 3 times / min; gastric pylorus opening size: 0 - 2 mm; gastric pylorus opening frequency: 3 times / min; gastric digestive juice secretion rate: 1.2 - 20 ml / min; hydrochloric acid secretion rate: adjusted according to pH value; gastric tilt angle: tilted 12° to the right from 0 - 5 min, 0° from 6 - 30 min, and tilted 42° to the left from 31 - 120 min; intestinal peristalsis frequency: 100 mm / min; intestinal digestive juice secretion rate: 1.2 - 2.2 ml / min; NaHCO3 secretion rate: 0.4 - 0.5 ml / min; total digestion time of the bionic stomach: 2 h; total digestion time of the bionic intestine: 3 h.

[0024] Preferably, step S4 includes: collecting digestion products from the bionic stomach and the end of the small intestine of the dynamic human bionic digestive system at different time periods, inactivating enzymes in a water bath at 90 - 100 °C for 10 - 20 min, cooling the digestion products and then centrifuging to separate the supernatant, and detecting the molecular weight distribution of the supernatant.

[0025] The present invention has at least the following beneficial effects:

[0026] (1) The present invention uses a dynamic bionic digestive system to process ejiao peptides, which is closer to the human environment, simulates the human digestion process, and obtains ejiao oligopeptides, so as to better release the blood-tonifying active substances in ejiao peptides, facilitate human absorption, and improve the bioavailability and blood-tonifying effect of ejiao peptides.

[0027] (2) In the processing stage of the digestion products, the present invention freeze-dries the digestion products into powder, and this processing method can make the products have better physiological activity compared with traditional drying methods such as baking and spray drying. Detailed Embodiments

[0028] It should be noted that the following detailed description is illustrative and is intended to provide further description of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work shall fall within the protection scope of the present invention.

[0031] Embodiment

[0032] This embodiment provides a method for preparing Ejiao oligopeptide using a dynamic bionic digestive system, including the following steps:

[0033] S1. Prepare a digestive juice simulation solution, which includes oral digestive juice, gastric digestive juice, and intestinal digestive juice.

[0034] In the prepared digestive juice simulation solution, the oral digestive juice includes: 15.11 mM KCl, 13.6 mM NaHCO3, 3.7 mM KH2PO4, 0.06 mM (NH4)2CO3, 0.15 mM MgCl2(H2O)6, 1.5 mM CaCl2(H2O)2, 150 U / ml α-amylase, and the pH is adjusted to 7 with 1 M hydrochloric acid; the gastric digestive juice includes: 47.25 mM NaCl, 6.9 mM KCl, 25 mM NaHCO3, 0.9 mM KH2PO4, 0.5 mM (NH4)2CO3, 0.12 mM MgCl2(H2O)6, 0.15 mM CaCl2(H2O)2, 3000 U / ml pepsin, and the pH is adjusted to 1.6 ± 0.1 with 6 M hydrochloric acid; the intestinal digestive juice includes: 38.44 mM NaCl, 6.8 mM KCl, 84.99 mM NaHCO3, 0.8 mM KH2PO4, 0.33 mM MgCl2(H2O)6, 0.6 mM CaCl2(H2O)2, 5 USP / ml trypsin, 13.35 mM bile salts, and the pH is adjusted to 6.8 with 6 M hydrochloric acid.

[0035] S2. Prepare an Ejiao peptide sample and simulate oral digestion: Weigh 25 g of Ejiao peptide powder, 155 g of ultrapure water, and 25 g of simulated oral digestive juice into a magnetic stirring water bath at 37 °C and stir for 3 min to mix evenly to simulate oral digestion.

[0036] S3. Start the dynamic human bionic digestive system, preheat it to 37 °C, add 20 ml of reserved gastric digestive juice to the dynamic human bionic digestive system to ensure that the low pH environment in the stomach can be fully simulated at the beginning of digestion. Subsequently, add the sample after oral digestion treatment to the bionic esophagus, and continuously and slowly pump gastric digestive juice and intestinal digestive juice into the stomach model and intestinal model of the system at the flow rate according to the preset parameters at each pump inlet to fully simulate the dynamic gastrointestinal digestion process of the human body digesting food.

[0037] In this embodiment, the dynamic human bionic digestive system is a dynamic bionic gastrointestinal digestion device, DHSI-IV, produced by Xiaodong Yijian (Suzhou) Instrument and Equipment Co., Ltd. The specific parameters are as follows:

[0038] Temperature: 37°C; gastric peristalsis frequency: 3 times / min; gastric pyloric opening size: 0 - 2 mm; gastric pyloric opening frequency: 3 times / min; gastric digestive juice secretion rate: 1.2 - 20 ml / min; hydrochloric acid secretion rate: automatically adjusted according to the set pH value; gastric tilt angle: tilted 12° to the right from 0 - 5 min, 0° from 6 - 30 min, and tilted 42° to the left from 31 - 120 min; intestinal peristalsis frequency: 100 mm / min; intestinal digestive juice secretion rate: 1.2 - 2.2 ml / min; NaHCO3 secretion rate: 0.4 - 0.5 ml / min; total digestion time of the bionic stomach: 2 h; total digestion time of the bionic intestine: 3 h.

[0039] S4. Collect the digestion products from the stomach or the end of the small intestine at different times, inactivate the enzymes in a 100°C water bath for 15 min, cool the digestion products and then centrifuge (5000 revolutions per minute, 15 min) to separate the supernatant and the precipitate, and detect the molecular weight distribution of the supernatant with reference to GB31645 - 2018.

[0040] The molecular weight distribution of the ejiao peptide (purchased from Shandong Hewang E-commerce Co., Ltd., product number 20240301) before digestion is shown in Table 1. The molecular weight distribution results of the ejiao peptide after simulated digestion are shown in Table 2. It can be seen from the results of Table 2 that the proportion of low molecular weight peptide segments increases significantly after bionic gastrointestinal simulation digestion.

[0041] Table 1 Molecular weight distribution of ejiao peptide before digestion

[0042] Molecular weight distribution (Da) Peak area percentage (%) >10000 0.81 10000-3000 6.91 5000-3000 4.59 ＜3000 92.28

[0043] Table 2 Molecular weight distribution of ejiao peptide after digestion

[0044]

[0045]

[0046] S5. After the detection is completed, lyophilize the supernatant into a powder to obtain the freeze-dried powder of ejiao oligopeptide.

[0047] S6. Use phenylhydrazine to establish a zebrafish anemia model to detect the efficacy of ejiao peptide in improving anemia. The indicators for detecting the efficacy of improving anemia include: the staining intensity of red blood cells in the heart and the hemoglobin content.

[0048] Specifically, the detection of the efficacy of improving anemia includes the following steps:

[0049] 1. Detection materials

[0050] 1.1. Sample preparation information

[0051] Before digestion, the ejiao peptides and freeze-dried ejiao peptide gastrointestinal tract powder were used, and the solvent was standard dilution water.

[0052] Positive control: Shengxuening tablets, hereinafter referred to as Shengxuening, are brownish-red tablets with the batch number 20240710, produced by Wuhan United Pharmaceutical Co., Ltd. The solvent is ultrapure water.

[0053] 1.2. Experimental animals

[0054] All zebrafish were raised in fish culture water at 28°C (water quality: 200 mg of instant sea salt was added to every 1 L of reverse osmosis water, the conductivity was 450 - 550 μS / cm; the pH was 6.5 - 8.5; the hardness was 50 - 100 mg / L CaCO3). They were provided by the company's fish culture center. The experimental animal use license number is: SYXK(Zhe)2022 - 0004. The feeding management meets the requirements of international AAALAC certification (certification number: 001458), and the IACUC ethical review number is: IACUC - 2024 - 10213 - 01.

[0055] 1.3. Instruments, consumables and reagents

[0056] Dissecting microscope (SZX7, OLYMPUS, Japan); CCD camera (VertA1, Shanghai Tusen Vision Technology Co., Ltd., China); Precision electronic balance (CP214, OHAUS, USA); 6-well plate (Zhejiang Beilanbo Biotechnology Co., Ltd., China); Automatic sample rapid grinder (JXFSTPRP - 24L, Shanghai Jingxin Experimental Equipment Technology Department, China); Ultrasonic cleaner (JP - 010T, Shenzhen Jiemeng Cleaning Equipment Co., Ltd., China); Multifunctional microplate reader (SPARK, TECAN, Austria); High-speed refrigerated centrifuge (Heraeus Fresco17, ThermoFisher, Germany); 96-well plate (NestBiotech, China).

[0057] Phenylhydrazine (batch number YH0170509, Shanghai Yihe Biotechnology Co., Ltd., China); absolute ethanol (batch number 20240312, Sinopharm Chemical Reagent Co., Ltd., China); o-dianisidine (batch number MKBX3619V, Sigma, USA); anhydrous sodium acetate (batch number F20090306, Sinopharm Chemical Reagent Co., Ltd., China); hydrogen peroxide solution (batch number H112517, Shanghai Aladdin Biochemical Technology Co., Ltd., China); dimethyl sulfoxide (DMSO, batch number I2229063, Shanghai Aladdin Biochemical Technology Co., Ltd., China); zebrafish hemoglobin Hb ELISA kit (batch number 202410, Shanghai Enzyme-linked Biotechnology Co., Ltd., China); sodium chloride injection (batch number S21091609, Hunan Kelun Pharmaceutical Co., Ltd., China); BCA protein concentration assay kit (batch number 19E24C89, BOSTER, China).

[0058] 2. Detection methods

[0059] 2.1. Determination of the maximum detectable concentration (MTC)

[0060] Wild-type AB strain zebrafish at 4 days post-fertilization (4 dpf) were randomly selected and placed in a 6-well plate, with 30 zebrafish in each well (experimental group). The samples were administered in water (concentrations are shown in Table 2), and a normal control group and a model control group were set up simultaneously, with a volume of 3 mL per well. After treatment at 28 °C for 6 h, except for the normal control group, phenylhydrazine was administered in water to establish a zebrafish anemia model in the remaining experimental groups. After continued treatment at 28 °C for 18 h, the MTC of the samples on the model zebrafish was measured, and the results are shown in Table 2. It can be seen from the results in Table 2 that the maximum detectable concentration (MTC) of the anemia-improving effect of the freeze-dried gastrointestinal powder of donkey-hide gelatin peptides is 500 μg / mL of the pure product.

[0061] Table 2 Experimental results of the concentration of the sample's anemia-improving effect (n = 30)

[0062]

[0063] 2.2 Evaluation of the anemia-improving effect (intensity of cardiac red blood cell staining)

[0064] Randomly select 4-dpf wild-type AB strain zebrafish and place them in a 6-well plate, with 30 zebrafish in each well (experimental group). Administer the sample in water solution (concentrations are shown in Table 3), with the positive control being Shengxuenning tablets at a concentration of 500 μg / mL. At the same time, set up a normal control group and a model control group, with a volume of 3 mL in each well. After treatment at 28°C for 6 h, except for the normal control group, establish a zebrafish anemia model by administering phenylhydrazine in water solution to the remaining experimental groups. After continuing the treatment at 28°C for 18 h, perform o-dianisidine staining. After the staining is completed, randomly select 10 zebrafish from each experimental group and take pictures under a dissection microscope. Use NIS-Elements D 3.20 advanced image processing software to collect data and analyze the staining intensity of red blood cells in the zebrafish heart. Evaluate the anemia-improving efficacy of the sample based on the statistical analysis results of this index. Use SPSS 26.0 software for statistical analysis. p < 0.05 indicates that the difference is statistically significant. The detailed results are shown in Table 3. It can be seen from the results in Table 3 that before digestion, both ejiao peptides and ejiao peptide gastroenteric freeze-dried powder have the efficacy of improving anemia, specifically manifested as increasing the staining intensity of red blood cells in the heart. The anemia-improving efficacy of ejiao peptide gastroenteric freeze-dried powder is better than that of ejiao peptides before digestion at the same concentration.

[0065] Table 3 Experimental results for evaluating the anemia-improving efficacy of the sample (n = 10)

[0066]

[0067] Compared with the model control group, *p < 0.05, **p < 0.01, ***p < 0.001.

[0068] Compared with ejiao peptide gastroenteric freeze-dried powder at 250 μg / mL, #p < 0.05, p < 0.001.

[0069] 2.3 Evaluation of anemia-improving efficacy (hemoglobin content)

[0070] Wild-type AB strain zebrafish at 4 dpf were randomly selected and placed in 6-well plates, with 30 zebrafish in each well (experimental group). The samples were administered in water solution (concentrations are shown in Table 4), the positive control was Shengxuenning tablets at a concentration of 500 μg / mL. At the same time, a normal control group and a model control group were set up, and the volume per well was 3 mL. Three parallel experiments were set up. After treatment at 28 °C for 6 h, except for the normal control group, phenylhydrazine was administered in water solution to the remaining experimental groups to establish a zebrafish anemia model. After continuing treatment at 28 °C for 18 h, zebrafish samples were collected according to the hemoglobin kit instructions, data were collected using a multifunctional microplate reader, and the hemoglobin content in zebrafish in each experimental group was analyzed. The efficacy of the samples in improving anemia was evaluated based on the statistical analysis results of this index. Statistical analysis was performed using SPSS 26.0 software, and p < 0.05 indicated that the difference was statistically significant. The detailed results are shown in Table 4. It can be seen from the results in Table 4 that before digestion, both ejiao peptide and freeze-dried ejiao peptide in the gastrointestinal tract had the efficacy of improving anemia, specifically manifested as an increase in hemoglobin content. The efficacy of freeze-dried ejiao peptide in the gastrointestinal tract in improving anemia was better than that of ejiao peptide before digestion.

[0071] Table 4 Experimental results of the efficacy evaluation of samples in improving anemia (hemoglobin content) (n = 3)

[0072]

[0073] Compared with the model control group, *p < 0.05, **p < 0.01.

[0074] Compared with freeze-dried ejiao peptide in the gastrointestinal tract at 250 μg / mL, #p < 0.05, ##p < 0.01.

[0075] In summary, in the present invention, ejiao peptide was treated using a dynamic bionic digestive system, which is closer to the human environment, simulates the human digestion process, and obtains ejiao oligopeptide to better release the blood-tonifying active substances in ejiao peptide, facilitating human absorption, improving the bioavailability and blood-tonifying effect of ejiao peptide; in the processing stage of the digestion product, the digestion product was freeze-dried into powder, and this processing method can make the product have better physiological activity compared with traditional drying methods such as drying and spray drying.

[0076] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing colla corii asini oligopeptide by using a dynamic bionic digestive system, characterized in that, It includes the following steps: S1. Prepare a digestive juice simulation solution, which includes oral digestive juice, gastric digestive juice, and intestinal digestive juice; S2. Simulate the oral digestion of the ejiao peptide sample; S3. Start the dynamic human bionic digestive system. After preheating, add the ejiao peptide into the system, and then gradually add the gastric digestive juice and intestinal digestive juice into the system quantitatively to simulate the dynamic gastrointestinal digestion process; S4. Collect the gastrointestinal digestion products, inactivate the enzymes in a water bath, cool them, and then centrifuge to separate the supernatant, and detect the molecular weight distribution of the supernatant; S5. After the detection is completed, freeze-dry the supernatant into powder to obtain low-molecular-weight ejiao peptide.

2. The method for preparing colla corii asini oligopeptide by using a dynamic bionic digestive system according to claim 1, characterized in that, It also includes the following steps: S6. Detect the efficacy of improving anemia of the obtained low-molecular-weight ejiao peptide. The indexes for detecting the efficacy of improving anemia include: the staining intensity of cardiac red blood cells and the hemoglobin content.

3. The method for preparing colla corii asini oligopeptide by using a dynamic bionic digestive system according to claim 2, characterized in that, In the detection of the efficacy of improving anemia, a zebrafish anemia model is established using phenylhydrazine.

4. The method for preparing ejiao peptides by using a dynamic bionic digestive system according to claim 1, characterized in that, In step S1, the oral digestive juice is prepared with KCl, NaHCO3, KH2PO4, (NH4)2CO3, MgCl2(H2O)6, CaCl2(H2O)2, α-amylase, and HCl as raw materials; the gastric digestive juice is prepared with NaCl, KCl, NaHCO3, KH2PO4, (NH4)2CO3, MgCl2(H2O)6, CaCl2(H2O)2, pepsin, and HCl as raw materials; the intestinal digestive juice is prepared with NaCl, KCl, NaHCO3, KH2PO4, MgCl2(H2O)6, CaCl2(H2O)2, pancreatin, bile salts, and HCl as raw materials.

5. The method for preparing colla corii asini oligopeptide by using a dynamic bionic digestive system according to claim 4, wherein The oral digestive juice includes: 14 - 16 mM KCl, 12 - 14 mM NaHCO3, 3 - 4 mM KH2PO4, 0.04 - 0.08 mM (NH4)2CO3, 0.1 - 0.2 mM MgCl2(H2O)6, 1 - 2 mM CaCl2(H2O)2, 5 - 200 U / ml α-amylase, and the pH value is 6.5 - 7.5; the gastric digestive juice includes: 46 - 48 mM NaCl, 6 - 8 mM KCl, 24 - 26 mM NaHCO3, 0.5 - 1.5 mM KH2PO4, 0.4 - 0.6 mM (NH4)2CO3, 0.08 - 0.15 mM MgCl2(H2O)6, 0.1 - 0.2 mM CaCl2(H2O)2, 100 - 4000 U / ml pepsin, and the pH value is 1 - 3; the intestinal digestive juice includes: 37 - 39 mM NaCl, 6 - 8 mM KCl, 83 - 85 mM NaHCO3, 0.5 - 1 mM KH2PO4, 0.2 - 0.5 mM MgCl2(H2O)6, 0.5 - 0.8 mM CaCl2(H2O)2, 0.1 - 6 USP / ml pancreatin, 5 - 25 mM bile salts, and the pH value is 6.5 - 7.

5.

6. The method for preparing colla corii asini oligopeptide by using a dynamic bionic digestive system according to claim 1, wherein Step S2 includes: Place the ejiao peptide, water, and oral digestive juice in a 37°C water bath, and stir them in the water bath to simulate oral digestion.

7. The method for preparing colla corii asini oligopeptide by using a dynamic bionic digestive system according to claim 6, wherein The mass ratio of the donkey-hide gelatin peptide, water and oral digestive juice is (2-3):(12-18):(2-3).

8. The method for preparing colla corii asini oligopeptide by using a dynamic bionic digestive system according to claim 1, wherein Step S3 includes: starting the dynamic human bionic digestive system, preheating it to 37°C, adding a certain amount of gastric digestive juice into the system in advance, then adding the donkey-hide gelatin peptide after oral digestion treatment into the bionic esophagus of the system, and continuously and slowly pumping gastric digestive juice and intestinal digestive juice into the gastric model and intestinal model of the system at the flow rate of the preset parameters to fully simulate the dynamic gastrointestinal digestion process of the human body digesting food.

9. The method for preparing Ejiao oligopeptide by using a dynamic bionic digestive system according to claim 1, characterized in that, In step S3, the parameter settings of the dynamic human bionic digestive system are as follows: temperature: 37°C; gastric peristalsis frequency: 3 times / min; gastric pyloric opening size: 0-2 mm; gastric pyloric opening frequency: 3 times / min; gastric digestive juice secretion rate: 1.2-20 ml / min; hydrochloric acid secretion rate: adjusted according to the pH value; gastric tilt angle: tilted 12° to the right in 0-5 min, 0° in 6-30 min, and tilted 42° to the left in 31-120 min; intestinal peristalsis frequency: 100 mm / min; intestinal digestive juice secretion rate: 1.2-2.2 ml / min; NaHCO3 secretion rate: 0.4-0.5 ml / min; total bionic gastric digestion time: 2 h; total bionic intestinal digestion time: 3 h.

10. The method for preparing colla corii asini oligopeptide by using a dynamic bionic digestive system according to claim 1, wherein, Step S4 includes: collecting the digestion products from the bionic stomach and the end of the small intestine of the dynamic human bionic digestive system at different time periods, inactivating the enzymes in a water bath at 90-100°C for 10-20 min, cooling the digestion products and then centrifuging them to separate the supernatant, and detecting the molecular weight distribution of the supernatant.

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