Preparation method and application of egg white peptide with hypoglycemic and lipid-lowering activity
Patent Information
- Application Number
- CN202610004194.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-05
- Publication Date
- 2026-04-03
AI Technical Summary
[0004]目前，蛋清肽的降糖降脂功能尚未得到充分挖掘，尤其是涉及降糖降脂功能的蛋清肽特征肽段鲜有报道
[0025]本发明的有益效果为：本发明提供的具有降糖降脂活性的蛋清肽的制备方法，经水合分散、双酶协同水解、离心、超滤脱盐、干燥获得。具有操作简单，酶解效率高等特点，具备经济技术可行性和结果的可靠性，而且所述制备方法采用的原料易得，价格便宜，降低了生产成本，适合规模化工业生产，获得的降糖降脂蛋清肽具有低分子量、食用安全、易于吸收等特性。
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Abstract
Description
Technical Field
[0001] This invention relates to the field of egg product processing technology, specifically to a method for preparing egg white peptides with hypoglycemic and lipid-lowering activities and their applications. Background Technology
[0002] Hyperlipidemia and diabetes are core contributing factors to cardiovascular disease, exhibiting a clear link and mutual influence. Diabetic patients often suffer from dyslipidemia, characterized by elevated total cholesterol and triglyceride levels, decreased high-density lipoprotein (HDL), and increased low-density lipoprotein (LDL). This type of lipid metabolism disorder not only exacerbates insulin resistance but also further damages pancreatic β-cell function. Currently, commonly used lipid-lowering and hypoglycemic drugs often have varying degrees of side effects, such as affecting the absorption of fat-soluble vitamins, causing gastrointestinal discomfort, inducing muscle toxicity, and liver and kidney damage. Therefore, utilizing natural active ingredients to improve lipid metabolism disorders has become a current research hotspot.
[0003] Eggs, as an important source of protein in our daily diet, have an amino acid profile in egg white protein that is highly similar to that of human serum albumin. This makes egg white a high-quality raw material for the preparation of bioactive peptides. Egg white peptides obtained through enzymatic hydrolysis are characterized by low molecular weight, safety for consumption, and easy absorption, and hold promise as natural-source active ingredients for exerting hypoglycemic and lipid-lowering activities.
[0004] Currently, the hypoglycemic and lipid-lowering functions of egg white peptides have not been fully explored, especially the characteristic peptide segments of egg white peptides involved in hypoglycemic and lipid-lowering functions are rarely reported. Therefore, developing a production process for egg white peptides with hypoglycemic and lipid-lowering functions can not only provide a theoretical basis and technical path for the research and development of related functional foods, but also help extend the egg processing industry chain, improve the situation of the single transformation path of the egg industry, and thus enhance the economic benefits of the industry. Summary of the Invention
[0005] The purpose of this invention is to provide a method for preparing egg white peptides with hypoglycemic and lipid-lowering activities and their applications.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] 1. A method for preparing egg white peptides with hypoglycemic and lipid-lowering activities, the steps of which are as follows:
[0008] (1) Dissolve 5% (m / v) egg white protein powder in deionized water. After dissolving completely, heat at 50-90 ℃ for 10-120 min and cool to room temperature to obtain egg white protein solution.
[0009] (2) Adjust the pH of the egg white protein solution in step (1) to 6.0-7.5, add enzyme preparation, and enzymatically hydrolyze at 30-70℃. After 1-12 h of enzymatic hydrolysis, inactivate the enzyme to obtain egg white protein hydrolysate.
[0010] (3) After cooling the egg white protein hydrolysate described in step (2), adjust the pH to 6.0-7.5, centrifuge at 10000 rpm for 10 min to collect the supernatant, and then ultrafilter the supernatant through an ultrafiltration membrane and collect the ultrafiltrate.
[0011] (4) The ultrafiltrate obtained in step (3) is freeze-dried to obtain hypoglycemic and lipid-lowering protein peptides.
[0012] The enzyme mentioned in step (2) is two of the following: flavor protease, bromelain, papain, trypsin, complex protease, ginger protease, kiwi protease and subtilis protease, with an enzyme activity of 4000-8000 U / g.
[0013] The molecular weight cutoff of the ultrafiltration membrane in step (3) is one or two of 10 kDa, 5 kDa, 3 kDa, and 1 kDa.
[0014] This invention also provides an egg white peptide prepared according to the egg white peptide preparation method with hypoglycemic and lipid-lowering activities as described above, comprising the following egg white peptide segments: whose amino acid sequences are: Ser-Asp-Phe-Gly-Val-Asp-Thr-Lys-Ser-Asp-His-Leu or Ile-Ser-Gln-Ala-Val-His-Ala-Ala-Hia-Ala-Glu-Ile-Asn-Glu or Asp-Asp-Asn-Lys-Val-Glu-Asp-Ile-Trp-Ser-Phe.
[0015] The aforementioned egg white peptide with hypoglycemic and lipid-lowering activities can be used to prepare hypoglycemic and lipid-lowering drugs.
[0016] The present invention provides a functional product, characterized in that its components include the above-mentioned egg white peptides with hypoglycemic and lipid-lowering activities.
[0017] This product includes at least one of the following features:
[0018] (1) Inhibits pancreatic lipase;
[0019] (2) Promotes the binding of bile salts;
[0020] (3) Inhibits cholesterol micelle solubility;
[0021] (4) Inhibit α-glucosidase;
[0022] (5) Lowering blood sugar;
[0023] (6) Lowering lipids.
[0024] The hypoglycemic and lipid-lowering protein peptides can be used alone or in combination with natural hypoglycemic and lipid-lowering active ingredients.
[0025] The beneficial effects of this invention are as follows: The method for preparing egg white peptides with hypoglycemic and lipid-lowering activities provided by this invention involves hydration dispersion, dual-enzyme synergistic hydrolysis, centrifugation, ultrafiltration desalting, and drying. It features simple operation, high enzymatic hydrolysis efficiency, economic and technical feasibility, and reliable results. Furthermore, the raw materials used in this preparation method are readily available and inexpensive, reducing production costs and making it suitable for large-scale industrial production. The obtained hypoglycemic and lipid-lowering egg white peptides have characteristics such as low molecular weight, food safety, and easy absorption.
[0026] The egg white peptides prepared according to this invention exhibit an inhibition rate of 17.87% against pancreatic lipase and 50.68% against α-glucosidase. Furthermore, through separation, purification, and bioinformatics screening, three previously unreported egg white peptide segments with hypoglycemic and lipid-lowering activities were identified. Their amino acid sequences are: Ser-Asp-Phe-Gly-Val-Asp-Thr-Lys-Ser-Asp-His-Leu (sequence abbreviation: SDFGVDTKSDFHL), Ile-Ser-Gln-Ala-Val-His-Ala-Ala-Hia-Ala-Glu-Ile-Asn-Glu (sequence abbreviation: ISQAVHAAHAEINE), and Asp-Asp-Asn-Lys-Val-Glu-Asp-Ile-Trp-Ser-Phe (sequence abbreviation: DDNKVEDIWSF). These three peptide segments can bind to pancreatic lipase receptors to achieve hypoglycemic and lipid-lowering effects. Based on this, the present invention can play a good auxiliary role in lowering blood sugar and lipids, and has good application prospects in the preparation of food-derived hypoglycemic and lipid-lowering foods or functional foods. Attached Figure Description
[0027] This invention appendix Figure 4 , of which:
[0028] Figure 1 MS / MS spectrum of SDFGVDTKSDFHL;
[0029] Figure 2 MS / MS spectrum of ISQAVHAAHAEINE;
[0030] Figure 3 MS / MS spectrum of DDNKVEDIWSF;
[0031] Figure 4 2D interaction diagram of SDFGVDTKSDFHL(a), ISQAVHAAHAEINE(b), DDNKVEDIWSF(c) with pancreatic lipase molecules. Detailed Implementation
[0032] The following embodiments are intended to further illustrate the technical solutions, operating steps and technical effects of the present invention through specific implementation methods and experimental data, so as to enable those skilled in the art to more intuitively and thoroughly understand the principles and application scenarios of the present invention.
[0033] Example 1:
[0034] (1) Dissolve 5% (m / v) egg white protein powder in deionized water by hydration dispersion method. After dissolving completely, heat at 90 °C for 10 min and cool to room temperature to obtain egg white protein solution.
[0035] (2) Adjust the pH of the egg white protein solution in step (1) to 7.5, and add 4000 U / g trypsin and 8000 U / g papain. Enzymatically hydrolyze at 70 °C. After 1 h of enzymatic hydrolysis, inactivate the enzyme to obtain the egg white protein hydrolysate. The degree of hydrolysis of the hydrolysate at this time is measured to be 8.77%.
[0036] (3) After cooling the egg white protein hydrolysate described in step (2), adjust the pH to 7.5, centrifuge at 10,000 rpm for 10 min to collect the supernatant, and perform ultrafiltration using 10 kDa and 1 kDa ultrafiltration membranes, and collect the ultrafiltrate.
[0037] (4) The ultrafiltrate from step (3) is freeze-dried to obtain hypoglycemic and lipid-lowering protein peptide powder.
[0038] The degree of hydrolysis in the above experimental steps was obtained according to the following determination method:
[0039] The degree of hydrolysis is defined as the ratio of cleaved peptide bonds to the total number of bonds per unit weight. The pH-stat method essentially measures the amount of hydrogen released when peptide bonds between amino acid molecules break during protein hydrolysis. + H + This will cause a decrease in the pH value of the solution, so the degree of hydrolysis can be calculated by the volume of NaOH added. The following is the formula for calculating the degree of hydrolysis using the pH-stat method:
[0040]
[0041] In the formula: h is the number of peptide bonds cleaved (mmol / g);
[0042] N is the concentration of NaOH (mol / L);
[0043] B is the volume (mL) of NaOH;
[0044] m p It refers to the mass (g) of egg white protein;
[0045] h tot It is the gram equivalent of peptide bonds per gram of egg white protein;
[0046] α represents the average degree of dissociation of the α-amino group, which is taken as 1.105.
[0047] Example 2:
[0048] (1) Dissolve 5% (m / v) egg white protein powder in deionized water by hydration dispersion method. After dissolving completely, heat at 70 °C for 30 min and cool to room temperature to obtain egg white protein solution.
[0049] (2) Adjust the pH of the egg white protein solution in step (1) to 7.0, and add 6000 U / g flavor protease and 6000 U / g complex protease. Enzymatically hydrolyze at 40 °C. After 8 h of enzymatic hydrolysis, inactivate the enzyme to obtain egg white protein hydrolysate. The degree of hydrolysis of the hydrolysate at this time is measured to be 18.45%. The method for measuring the degree of hydrolysis is the same as in Example 1.
[0050] (3) After cooling the egg white protein hydrolysate described in step (2), adjust the pH to 7.0, centrifuge at 10,000 rpm for 10 min to collect the supernatant, and use 5 kDa and 3 kDa ultrafiltration membranes for ultrafiltration, and collect the ultrafiltrate.
[0051] (4) The ultrafiltrate from step (3) is freeze-dried to obtain hypoglycemic and lipid-lowering protein peptide powder.
[0052] Example 3:
[0053] (1) Dissolve 5% (m / v) egg white protein powder in deionized water by hydration dispersion method. After dissolving completely, heat at 60 °C for 60 min and cool to room temperature to obtain egg white protein solution.
[0054] 2) Adjust the pH of the egg white protein solution described in step 1) to 6.0, and add 5000 U / g bromelain and 7000 U / g papain. Enzymatically hydrolyze the solution at 30 °C for 12 h. After hydrolysis, the enzymes are inactivated to obtain the egg white protein hydrolysate. The degree of hydrolysis of the hydrolysate at this time is measured to be 13.70%. The method for measuring the degree of hydrolysis is the same as in Example 1.
[0055] 3) After cooling the egg white protein hydrolysate described in step 2), adjust the pH to 6.0, centrifuge at 10,000 rpm for 10 min, collect the supernatant, and perform ultrafiltration using 10 kDa and 1 kDa ultrafiltration membranes, and collect the ultrafiltrate.
[0056] 4) The ultrafiltrate obtained in step 3) is freeze-dried to obtain hypoglycemic and lipid-lowering protein peptide powder.
[0057] Example 4:
[0058] (1) Dissolve 5% (m / v) egg white protein powder in deionized water by hydration dispersion method. After dissolving completely, heat at 50 °C for 120 min and cool to room temperature to obtain egg white protein solution.
[0059] (2) Adjust the pH of the egg white protein solution in step (1) to 6.5, and add 4000 U / g flavor protease and 8000 U / g trypsin. Enzymatically hydrolyze at 60 °C. After 4 h of enzymatic hydrolysis, inactivate the enzyme to obtain egg white protein hydrolysate. The degree of hydrolysis of the hydrolysate at this time is measured to be 13.31%. The method for measuring the degree of hydrolysis is the same as in Example 1.
[0060] (3) After cooling the egg white protein hydrolysate described in step (2), adjust the pH to 6.5, centrifuge at 10,000 rpm for 10 min to collect the supernatant, and then ultrafilter the supernatant through ultrafiltration membranes with a cutoff of 10 kDa, 5 kDa, 3 kDa and 1 kDa to collect four different molecular weight ultrafiltrates.
[0061] (4) The ultrafiltrate obtained in step (3) was freeze-dried to obtain hypoglycemic and lipid-lowering protein peptide powder. Its pancreatic lipase inhibition rate, bile salt binding capacity and cholesterol micelle solubility inhibition rate were measured. The results are shown in Table 1.
[0062] Table 1. Lipid-lowering activity of egg white protein hydrolysates of different molecular weights
[0063]
[0064] The experimental data in the above experimental steps were obtained according to the following measurement methods:
[0065] (1) Determination of pancreatic lipase inhibition rate
[0066] Prepare a 1 mg / mL solution of 4-nitrobenzene laurate substrate (containing 1% Trition X-100) using 0.05 mol / L sodium acetate buffer. Dissolve the prepared substrate solution in a 90°C water bath, mix thoroughly, and then cool to room temperature. Dissolve porcine pancreatic lipase at a concentration of 5 mg / mL in 100 mmol / L Tris-HCl buffer (pH 8.2), and then centrifuge at 5000g for 10 min to obtain the supernatant. Add 200 μL of sample solution, 500 μL of substrate solution, 400 μL of buffer solution, and 300 μL of lipase solution sequentially. Incubate at 37 °C for 2 hours. Use Tris-HCl buffer instead of pancreatic lipase as the sample background, and use Tris-HCl buffer instead of the sample as the blank. Use Tris-HCl buffer instead of both the sample and pancreatic lipase as the blank background. Centrifuge at 10000 g for 1 min. Add 200 μL of supernatant to each well of a 96-well plate and record the absorbance at 420 nm. Calculate the pancreatic lipase inhibition rate using the following formula: Inhibition rate (%) = 100 - (A sample - A sample blank) / (A blank - A blank control) × 100
[0067] (2) Determination of bile salt binding capacity
[0068] Construction of the bile salt standard curve: Sodium cholate, sodium glycocholate, and sodium taurocholate (1 mmol / L) were diluted to different concentration gradients using 0.1 mol / L PBS buffer (pH 6.3). 2.5 mL of each bile salt standard solution was placed in a 15 mL thick-walled pressure-resistant bottle, and 7.5 mL of 60% sulfuric acid solution was added. The solution was incubated at 70 ℃ for 25 min, cooled in an ice bath, and 200 μL was added to each well of a 96-well plate. The absorbance at 387 nm was measured. A standard curve was plotted with the molar concentration of each bile salt on the x-axis and the absorbance on the y-axis.
[0069] Bile salt binding capacity determination: 8 mL of bile salt solution (1 mmol / L sodium cholate, sodium glycocholate, and sodium taurocholate) was added to 1 mL of sample solution and 1 mL of 0.1 mol / L PBS buffer (pH 6.3) (blank group), respectively. The solutions were incubated at 37℃ with shaking for 2 h, followed by centrifugation at 4500 rpm for 20 min. 2.5 mL of the supernatant was transferred to a stoppered test tube, and 7.5 mL of 60% sulfuric acid solution was added. The tubes were incubated at 70℃ for 30 min, then cooled to room temperature in an ice-water bath, and the absorbance was measured at 387 nm. The bile salt concentration in the supernatant was calculated from the standard curve. Binding rate (%) = (C0 - C1) / C0 × 100, where C0 is the bile salt concentration in the blank group and C1 is the bile salt concentration in the sample group.
[0070] (3) Determination of cholesterol micelle solubility inhibition rate
[0071] The simulated bile micelle solution system consisted of 0.01 mmol / L sodium taurocholate, 135 mmol / L NaCl, 5 mmol / L oleic acid, 2 mmol / L cholesterol, 15 mmol / L pH 7.4 sodium phosphate buffer, and 5 mg / mL sample solution per milliliter of micelles. The blank was a micelle solution without sample. The micelles were homogenized at 400 W for 30 min, then incubated at 37 ℃ for 24 h, centrifuged at 8000 g for 30 min, and the supernatant was collected. The cholesterol concentration was determined using a total cholesterol kit, and the cholesterol micelle solubility inhibition rate was calculated using the following formula: Inhibition rate (%) = (M0-M1) / M0 × 100, where M0 is the bile salt concentration in the blank group and M1 is the bile salt concentration in the sample group.
[0072] In vitro lipid-lowering activity assays showed that egg white protein hydrolysates with a molecular weight of 1-3 kDa exhibited the best lipid-lowering activity. Based on this, the inventors used egg white protein hydrolysates with a molecular weight of 1-3 kDa as the research subject to conduct related blood glucose-lowering assays.
[0073] Example 5:
[0074] (1) Dissolve 5% (m / v) egg white protein powder in deionized water by hydration dispersion method. After dissolving completely, heat at 80 °C for 20 min and cool to room temperature to obtain egg white protein solution.
[0075] (2) Adjust the pH of the egg white protein solution in step (1) to 7.5, and add 4000 U / g flavor protease and 8000 U / g trypsin. Enzymatically hydrolyze at 50 °C. After 6 h of enzymatic hydrolysis, inactivate the enzyme to obtain egg white protein hydrolysate. The degree of hydrolysis of the hydrolysate at this time is measured to be 13.31%. The method for determining the degree of hydrolysis is the same as in Example 1.
[0076] (3) After cooling the egg white protein hydrolysate described in step (2), adjust the pH to 7.5, centrifuge at 10,000 rpm for 10 min to collect the supernatant, and use 3 kDa and 1 kDa ultrafiltration membranes to perform ultrafiltration, and collect 1-3 kDa ultrafiltrate.
[0077] 4) The ultrafiltrate obtained in step 3) was freeze-dried to obtain hypoglycemic and lipid-lowering protein peptide powder, and its glucosidase inhibition rate was determined to be 50.68%.
[0078] The α-glucosidase inhibition rate in the above experimental steps can be obtained by the following determination method:
[0079] α-Glucosidase and p-nitrobenzene-α-D-glucopyranoside (PNPG) were dissolved in 0.1 mol / L PBS buffer (pH 6.8). 100 μL of sample solution (with buffer as a blank) and 100 mL of enzyme solution (1 U / mL) were added to a 96-well plate. The plate was incubated at 37°C for 10 min, then 100 μL of PNPG (2.5 mmol / L) was added, and the plate was incubated for another 30 min. The reaction was terminated by adding 100 μL of Na₂CO₃ (1 M), and the absorbance was measured at 405 nm. No enzyme solution was added to the control. The α-glucosidase inhibition rate was calculated using the following formula: Inhibition rate (%) = 100 - (Sample A - Sample A Blank) / (Blank A - Blank A Control) × 100.
[0080] Example 6:
[0081] Based on bioinformatics, hypoglycemic and lipid-lowering peptides were screened. Egg white protein hypoglycemic and lipid-lowering peptides were identified by mass spectrometry, and the identified peptides were analyzed by molecular docking.
[0082] The peptides were desalted using a C18 desalting column tip (Thermo Scientific, USA) according to the manufacturer's instructions. The desalted peptides were then vacuum centrifuged and dried before being analyzed by liquid chromatography-tandem mass spectrometry.
[0083] Peptide separation was performed using a self-packed loaded column (100 µm × 2 cm) and a C18 separation capillary column (75 µm × 15 cm), with 1.9 µm C18 bulk packing material (Dr. Maisch GmbH, Germany). The mobile phases (A: aqueous solution containing 0.1% formic acid; B: 80% acetonitrile solution containing 0.1% formic acid) were driven and controlled by a Dionex Ultimate 3000 RPLC nano-liquid chromatography system (Thermo Fisher Scientific). The liquid phase gradient program was as follows: 2% B phase for the first 8 minutes of analysis; increasing from 2% B phase to 10% B phase over 8 to 9 minutes; increasing from 10% B phase to 44% B phase over 9 to 63 minutes; and increasing from 44% B phase to 99% B phase over 63 to 68 minutes.
[0084] For samples analyzed using the Orbitrap Fusion LUMOS Tribrid mass spectrometer, precursor ions were ionized at +2.0 kV using an EASY-Spray ion source (Thermo Fisher Scientific), with the injection capillary temperature maintained at 320°C. Full scans of peptide precursor ions were performed on the Orbitrap, with a mass range of 150–1600 Th, an automatic gain control target of 400,000, a maximum injection time of 50 ms, an RF lens voltage of 30%, and a resolution of 60,000 at 200 m / z. Single isotope precursor ion selection was enabled, and data-dependent MS / MS scans (3 seconds per cycle) were performed on peptide precursor ions with charge states z=1–7. The dynamic exclusion time was set to 15 seconds, and the exclusion window was ±10 ppm of the single isotope mass number.
[0085] Automatic scan range determination was enabled during HCD scanning. Precursor ions were selected using a quadrupole with an isolation window of 1.6 Th. Product ions were detected in Orbitrap with an initial mass of 110 Th, an automatic gain control target of 50,000, a maximum injection time of 30 ms, an HCD collision energy of 30%, and a resolution of 15,000.
[0086] Data analysis was performed using Thermo Proteome Discoverer 2.4 software. The database searched was the SwissProt chicken protein database (TaxID=9031 and its subclasses, reviewed protein sequences, totaling 2303 sequences). Methionine oxidation was set as a variable modification. The precursor ion mass error tolerance was 10 ppm, and the fragment ion tolerance was 0.02 Da. Enzyme digestion was set to non-specific digestion. Peptide spectrum matching results were validated using the Percolator algorithm with the q-value corresponding to a 1% false discovery rate. The mass spectrometry results are shown below. Figure 1 As shown, some typical polypeptide secondary spectra are as follows: Figure 2 As shown.
[0087] The resolved peptide sequence was molecularly docked with pancreatic lipase (PDB ID: 1ETH) using Discovery Studio 2019. Only the A chain of pancreatic lipase was retained for analysis, excluding cocrystallized molecules and other polypeptide chains. Pretreatments such as dehydration and hydrogenation were performed, and an appropriate active site was set (x: 54.78 y: 46.84 z: 122.07), with a radius of 9. After minimizing the energy of the ligand, semi-flexible molecular docking was performed with pancreatic lipase. Some typical results are shown in Table 2.
[0088] Table 2. Peptide amino acid sequences and docking energies with pancreatic lipase molecules
[0089]
[0090] Pancreatic lipase is a lipophilic lipase whose catalytic activity depends on six major amino acid residues. Ser153, Asp177, and His264 together form an acylase catalytic triad; Phe78, His152, and Phe216 may be involved in substrate binding or the formation of inhibitory sites. Therefore, peptides binding to these residues or functional sites can regulate the conformational dynamics and catalytic function of lipase through interactions, thereby achieving a lipid-lowering effect. Visual analysis of three peptides, SDFGVDTKSDFHL, ISQAVHAAHAEINE, and DDNKVEDIWSF, yielded the following results: Figure 3 As shown in the diagram, the 2D interaction diagram of the three peptides with pancreatic lipase shows that the peptides form hydrogen bonds with different amino acids (such as Cys 182, Lys 181, Phe 78, and Ile79) near the active site of pancreatic lipase. Furthermore, salt bridges, π-π stacking, and hydrophobic interactions also interact with residues near the active site of pancreatic lipase (such as Tyr 115, His 264, Phe 216, Ser 153, Pro 181, Ala 179, Arg257, and Val 260), similar to common lipid-lowering active sites.
[0091] The operational terms used in this invention, such as hydration dispersion, centrifugation, ultrafiltration desalination, drying, mass spectrometry analysis, and molecular docking, are all common technical terms in the field, and their meanings are clearly defined, so they will not be repeated. The enzyme preparations used (such as flavor protease, bromelain, papain, trypsin, complex protease, ginger protease, kiwi protease, and subtilisin) are all commercially available conventional products that can be directly purchased by those skilled in the art. Other raw materials not specifically mentioned are also standard commercially available materials or products prepared by conventional methods in the field. Supplier information for related reagents, instruments, and consumables is not limited, and all can be obtained through conventional commercial channels.
[0092] It should be further noted that the above embodiments are only used to illustrate the technical solutions of the present invention and do not constitute a limiting constraint; even though the present invention has been described in detail based on the embodiments, those skilled in the art can still make reasonable adjustments to the technical solutions or make equivalent substitutions for some / all of the technical features, and such modifications or substitutions do not deviate from the core technical scope of the present invention.
Claims
1. A method for preparing egg white peptides with hypoglycemic and lipid-lowering activities, characterized in that... Includes the following steps: (1) Dissolve 5% m / v egg white protein powder in deionized water. After dissolving completely, heat at 50-90 ℃ for 10-120 min and cool to room temperature to obtain egg white protein solution. (2) Adjust the pH of the egg white protein solution in step (1) to 6.0-7.5, add enzyme preparation, and enzymatically hydrolyze at 30-70 ℃. After 1-12 h of enzymatic hydrolysis, inactivate the enzyme to obtain egg white protein hydrolysate. (3) After cooling the egg white protein hydrolysate described in step (2), adjust the pH to 6.0-7.5, centrifuge at 10000 rpm for 10 min to collect the supernatant, and then ultrafilter the supernatant through an ultrafiltration membrane and collect the ultrafiltrate. (4) The ultrafiltrate obtained in step (3) is freeze-dried to obtain hypoglycemic and lipid-lowering protein peptides.
2. The method for preparing egg white peptides with hypoglycemic and lipid-lowering activities according to claim 1, characterized in that: The enzyme mentioned in step (2) is two of the following: flavor protease, bromelain, papain, trypsin, complex protease, ginger protease, kiwi protease and subtilis protease, with an enzyme activity of 4000-8000 U / g.
3. The method for preparing an egg white peptide with hypoglycemic and lipid-lowering activity according to claim 1, characterized in that: The molecular weight cutoff of the ultrafiltration membrane in step (3) is one or two of 10 kDa, 5 kDa, 3 kDa, and 1 kDa.
4. An egg white peptide with hypoglycemic and lipid-lowering activities, characterized in that: The egg white peptide prepared according to the method of claim 1-3 with hypoglycemic and lipid-lowering activity includes the following egg white peptide segments, whose amino acid sequences are: SDFGVDTKSDFHL or ISQAVHAAHAEINE or DDNKVEDIWSF.
5. The egg white peptide with hypoglycemic and lipid-lowering activity as described in claim 4 can be used to prepare hypoglycemic and lipid-lowering drugs.
6. A functional product, characterized in that: Its components include the egg white peptides described in section 4, which have hypoglycemic and lipid-lowering activities.
7. The functional product according to claim 6, characterized in that, Includes at least one of the following functions: (1) Inhibits pancreatic lipase; (2) Promotes the binding of bile salts; (3) Inhibits cholesterol micelle solubility; (4) Inhibit α-glucosidase; (5) Lowering blood sugar; (6) Lowering lipids.