Sesame umami peptide with antioxidant activity and application thereof

Abstract

The invention discloses a sesame umami peptide with antioxidant activity and application thereof, the amino acid sequence of the sesame umami peptide is at least one of GFE (Gly-Phe-Glu), YMD (Tyr-Met-Asp) and RFT (Arg-Phe-Thr), and the sesame umami peptide belongs to the technical field of bioactive peptides. Three novel umami peptides are found and identified from sesame protein in combination with virtual enzymolysis, directional screening and molecular docking, sensory evaluation and electronic tongue analysis prove that the umami peptides GFE, YMD and RFT have good umami characteristics and have a good umami increasing effect on sodium glutamate, the umami threshold value is 0.07-0.36 mmol / L, and meanwhile, the three umami peptides all have antioxidant activity. The novel umami peptide is excavated from the sesame, the utilization value of sesame byproducts can be improved, the extracted umami peptide can also be used as a flavor enhancer or applied to preparation of the flavor enhancer, a new raw material basis is provided for development of the flavor enhancer, seasonings and functional food, and good application prospects and important application value are achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of bioactive peptides, and in particular relates to a sesame umami peptide with antioxidant activity and an application thereof. Background Art

[0002] Umami peptides are a new type of flavor enhancer with unique flavor and nutritional value. They can not only enhance the umami taste of food, but also make sweetness sweeter, saltiness saltier, reduce sourness and bitterness, and make the taste of food softer. The advantages of umami peptides are that they are safe, nutritious, natural and non-toxic, and can meet the low sodium intake needs of special populations, such as hypertensive patients. After consumption, they can provide many benefits to human health, so they are widely used in food additives and supplement enhancers. In addition, umami peptides have good processing characteristics in food processing and meet the development requirements of green food. Bioactive peptides with antioxidant effects are a class of natural antioxidants that can scavenge free radicals, reduce cell oxidative stress damage, promote cell metabolism and regeneration, and delay aging. They can be used as functional ingredients to control food oxidation and deterioration and improve food health effects. Therefore, antioxidant umami peptides, as peptide compounds that combine antioxidant properties and enhance food umami, have broad application prospects in the food industry and have important development significance. The flavoring effect of umami peptides is related to their receptors. Current studies have confirmed that umami receptors mainly include heterodimer T1R1 / T1R3 receptors, etc. In terms of factors affecting flavor, the structure of umami peptides such as peptide chain length, amino acid composition, amino acid sequence and peptide chain conformation will affect their flavoring effect. External factors such as temperature, moisture, pH value, salt, hydrolysis degree, inorganic ions, the multiplication of umami components and the type of hydrolase will also affect the flavor of umami peptides. In general, umami peptides, as a new type of food additive, have significant flavor and freshness enhancement effects, and have broad development and application prospects in the food industry. However, the types of umami peptides reported in the prior art are limited, and the exploration of new umami peptides is one of the current research hotspots. With the development of bioinformatics, virtual enzymolysis, computer model screening and molecular docking technology have been widely used in the screening and prediction of bioactive peptides. Umami peptides interact with umami receptors T1R1 / T1R3, activate the cascade signal transmission of the taste system, and make the brain perceive umami. This provides an effective method for the efficient screening of umami peptides and revealing the interaction between umami peptides and their receptors. Sesame tastes fresh and fragrant, is rich in nutrients, and is widely used. Whether as a food raw material or a medicinal material, it is deeply loved by people. It is rich in various proteins, especially sesame meal after oil extraction contains 30-50% protein, which is a high-quality source of plant protein. At present, there are no reports on umami peptides derived from sesame or sesame by-products, especially sesame umami peptides with antioxidant activity. Summary of the invention

[0003] Technical problems to be solved: In view of the above technical problems, the purpose of the present invention is to disclose a sesame umami peptide with antioxidant activity and its application. The amino acid sequence of the umami peptide derived from sesame protein is at least one of GFE (Gly-Phe-Glu), YMD (Tyr-Met-Asp) and RFT (Arg-Phe-Thr), belonging to the technical field of bioactive peptides. The present invention combines virtual enzymolysis, directional screening and molecular docking technology to discover and identify three new umami peptides from sesame protein. After sensory evaluation and electronic tongue analysis, it is verified that the umami peptides GFE, YMD and RFT have good umami characteristics and have a good umami effect on sodium glutamate. The umami threshold is 0.07-0.36mmol / L. At the same time, the antioxidant activity of the umami peptides is determined, and it is found that the three umami peptides have antioxidant activity. The present invention mines new umami peptides from sesame protein, which can not only improve the utilization value of sesame protein, but also provide a new raw material basis for the development of umami agents and condiments, and has good application prospects and important application value.

[0004] Technical solution: A sesame umami peptide with antioxidant activity, the sesame umami peptide comprising peptide GFE, peptide YMD and peptide RFT, wherein the amino acid sequence of peptide GFE is Gly-Phe-Glu, the amino acid sequence of peptide YMD is Tyr-Met-Asp, and the amino acid sequence of peptide RFT is Arg-Phe-Thr. Furthermore, the umami threshold of the sesame umami peptide is 0.07-0.36 mmol / L. Furthermore, the peptide GFE, peptide YMD and peptide RFT have the activity of scavenging DPPH free radicals, wherein the umami peptide YMD has the activity of scavenging ABTS free radicals. The method for preparing the sesame umami peptide with antioxidant activity described in any one of the above items comprises the following steps: S1. Use BIOPEP-UWM tool to perform virtual enzymatic hydrolysis on sesame 11S globulin and sesame 2S globulin to obtain a set of theoretical peptide sequences; S2. Preliminary screening of the theoretical peptide sequence set, and secondary screening by duplicate analysis and PeptideRanker scoring; S3. Screening of potential umami peptides using iUmami-SCM, Umami_YYDS and Tastepeptides_DM models; S4. Evaluate the water solubility, allergenicity, stability and toxicity of potential umami peptides, and screen out umami peptides with good water solubility, no allergenicity, no toxicity and good stability; S5. Use molecular docking technology to simulate the binding of umami peptides to umami receptors T1R1 / T1R3 and screen candidate umami peptides; S6. Synthesize candidate umami peptides using a biological solid phase synthesis method; S7. Verification test, verifying the candidate umami peptide to obtain the umami peptide; The proteases for the virtual enzymatic hydrolysis in step S1 include EC 3.4.21.1, EC 3.4.21.4, EC 3.4.23.1, EC.3.4.21.64, EC 3.4.21.36, EC.3.4.21.26, EC 3.4.21.19, EC 3.4.24.27, EC 3.4.21.2, EC 3.4.21.7, EC 3.4.21.20, EC 3.4.22.8, EC 3.4.21.39, EC 3.4.22.2, EC 3.4.22.3, EC3.4.21.37, EC 3.4.21.3, EC 3.4.21.5, EC 3.4.21.71, EC 3.4.22.32, EC 3.4.21.82, EC3.4.21.83, EC 3.4.22.53, EC 3.4.22.25, EC 3.4.21.96, EC 3.4.13.9, EC 3.4.23.1, EC3.4.24.30, EC 3.4.21.62, EC 3.4.23.4, EC 3.4.22.67, EC 3.4.21.19. A sesame protein hydrolysate, comprising one or more of the peptide GFE, peptide YMD and peptide RFT according to claim 1. Application of the sesame umami peptide with antioxidant activity described in any one of the above items in the preparation of food, food additives and health products. The use of any of the above-mentioned sesame umami peptides with antioxidant activity in improving the umami taste and flavor of food. The use of the above-mentioned sesame protein hydrolysate in preparing food, food additives and health products. Beneficial effects: 1. The present invention utilizes machine learning and bioinformatics to screen out three umami peptides in sesame protein, namely peptide GFE (Gly-Phe-Glu), peptide YMD (Tyr-Met-Asp) and peptide RFT (Arg-Phe-Thr), and peptide GFE, peptide YMD and peptide RFT can all bind to the umami receptor T1R1 / T1R3 subunit to form a stable composite conformation; in addition, sensory evaluation and electronic tongue analysis have shown that 1 mg / mL of peptide GFE, peptide YMD and peptide RFT have good umami characteristics and umami enhancement effects, and their umami thresholds are 0.07-0.36 mmol / L. 2. The present invention uses a computer method to virtually enzymatically hydrolyze proteins and combines it with machine learning screening, and then uses molecular docking technology for composite screening to obtain umami peptides in sesame protein. This can avoid the time-consuming and labor-intensive shortcomings caused by random cleavage of traditional proteases combined with step-by-step separation and purification, while reducing the loss of polypeptides caused by tedious and complicated experimental steps, and shortening the screening time of umami peptides in sesame protein to the greatest extent. It has the characteristics of high efficiency, high screening efficiency, high accuracy and repeatability. 3. The umami peptide of the present invention has the antioxidant activity of scavenging free radicals, and has both antioxidant properties and the function of enhancing the umami taste of food. It provides a new raw material basis for the development of umami agents and condiments, and also provides good technical support for the screening and development of umami peptides. It has broad application prospects in functional foods and condiments. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 3D structures of peptide GFE (A), peptide YMD (B), and peptide RFT (C); Figure 2 The structural model of umami taste receptor T1R1 / T1R3 (A) and homology modeling Ramachandran diagram (B); Figure 3 The molecular docking analysis results of peptide GFE (A), peptide YMD (B), peptide RFT (C) and umami taste receptor T1R1 / T1R3; Figure 4 HPLC analysis chart and mass spectrometry analysis chart of peptide GFE, peptide YMD and peptide RFT; Figure 5 It is the sensory evaluation radar chart of peptide GFE, peptide YMD and peptide RFT; Figure 6 It is the freshness-enhancing effect of peptide GFE, peptide YMD and peptide RFT. DETAILED DESCRIPTION The present invention will be further described below in conjunction with embodiments, which are explanations of the present invention and are not limited to the following embodiments: Example 1 The method for screening potential umami peptides from sesame protein comprises the following steps: S1. Determination of sesame protein and protease The 11S globulin (NCBI ID: Q9XHP0) and 2S albumin (NCBI ID: Q9XHP1) with high abundance in sesame protein were selected from the NCBI database, and 33 proteases in the BIOPEP-UWM enzymatic hydrolysis system were selected as hydrolases. S2. Virtual Enzymatic Hydrolysis of Sesame 11S Globulin and Sesame 2S Globulin The BIOPEP-UWM tool was used to perform virtual enzymatic hydrolysis of sesame protein, as follows: Use the enzymatic digestion program of the BIOPEP-UWM tool (https: / / biochemia.uwm.edu.pl / biopep-uwm / ) to input the amino acid sequences of the two sesame proteins into "Paste the sequence" through "Bioactive peptides", "ANALYSIS", "ENZYME(S)ACTION", "for your sequence" in sequence, select 33 in "Enzyme id", and click "View the report with the results" for virtual enzymatic digestion to obtain the theoretical peptide sequences. The ID numbers of the 33 proteases are EC 3.4.21.1, EC 3.4.21.4, EC 3.4.23.1, EC.3.4.21.64, EC 3.4.21.36, EC.3.4.21.26, EC 3.4.21.19, EC 3.4.24.27, EC 3.4.21.2, EC 3.4.21.7, EC 3.4.21.20, EC 3.4.22.8, EC 3.4.21.39, EC 3.4.22.2, EC 3.4.22.3, EC3.4.21.37, EC 3.4.21.3, EC 3.4.21.5, EC 3.4.21.71, EC 3.4.22.32, EC 3.4.21.82, EC3.4.21.83, EC 3.4.22.53, EC 3.4.22.25, EC 3.4.21.96, EC 3.4.13.9, EC 3.4.23.1, EC3.4.24.30, EC 3.4.21.62, EC 3.4.23.4, EC 3.4.22.67, EC 3.4.21.19, obtain a theoretical peptide sequence set; S3. Screen the peptide molecules with 2-9 amino acid sequences in the theoretical peptide sequence set, perform duplicate analysis, remove the discovered umami peptide sequences, and then screen the peptides with PeptideRanker scores greater than 0.5, a total of 237; S4. Three peptide sequence-based machine learning models iUmami-SCM, Umami_YYDS and Tastepeptides_DM were used to predict the theoretical peptide taste characteristics, and peptides that simultaneously met the iUmami-SCM prediction of umami, Umami_YYDS score greater than 0.9 and Tastepeptides_DM score greater than 0.8 were selected to obtain potential umami peptides. S5. Analysis of water solubility, allergenicity, stability and toxicity of potential umami peptides The water solubility, allergenicity, stability and toxicity of the potential umami peptide segments in Example 1 were analyzed using admetSAR, ToxinPred and AllerTOPv.2.0, and those with good water solubility, no allergenicity, strong stability and low toxicity were screened. Table 1 Machine learning model and bioinformatics screening of potential umami peptides As shown in Table 1, a total of 7 peptide sequences showed potential umami properties, and all of them were non-toxic and non-allergenic, and had good water solubility and stability. Since the umami taste of the peptides is related to glutamic acid (E), aspartic acid (D), glycine (G), proline (P), phenylalanine (F), arginine (R), asparagine (N) and glutamine (Q); and lower molecular weight peptides have higher umami potential, peptide GFE, peptide YMD and peptide RFT are preferred as potential umami peptides for subsequent research. Example 2 Molecular docking targeted screening of umami peptides Molecular docking technology was used to simulate the binding of umami peptides to umami receptors T1R1 / T1R3, and candidate umami peptides were obtained through targeted screening. The specific process is as follows: The amino acid sequences of umami taste receptors T1R1 / T1R3 were taken from UniprotKB (https: / / www.uniprot.org / ), with accession numbers Q7RTX1 and Q7RTX0. Metabotropic glutamate receptors were used as templates (PDB ID: 1EWK) for homology modeling of the ligand binding regions of T1R1 / T1R3. SWISS-MODEL (https: / / swissmodel.expasy.org / ) was used to perform homology modeling of T1R1 / T1R3 based on the sequence homology between the receptor and the template. To further study and confirm the reliability of the homology model, the constructed model was transplanted into the software named SAVESv6.0 (https: / / saves.mbi.ucla.edu / ) for evaluation using the Ramachandran plot. Discovery Studio performed molecular docking of potential umami peptides with T1R1 / T1R3, analyzing the binding energy and sites between umami peptides and umami receptors. The 3D structures of peptide GFE, peptide YMD and peptide RFT are shown in the figure. Figure 1 As shown, the homology model and Laplace diagram of umami taste receptor T1R1 / T1R3 are shown in Figure 2 The molecular docking results of the peptide and umami taste receptor protein are shown in Figure 3 shown. Depend on Figure 2It can be seen that 98.1% of the amino acid residues in the T1R1 / T1R3 model (89.4% in the optimal region and 8.7% in the marginal region) are in the allowed region, and only 1.0% of the amino acids are in the unreasonable region. In the Laplace plot, when more than 90% of the amino acid residues are in the allowed range, it means that the model is reasonable. Figure 2 The results show the reliability of the model. As shown in Table 2, sesame umami peptide can achieve good docking with T1R1 / T1R3. Figure 3 It can be seen that Figure 3 The interactions between peptide YMD, peptide RFT, peptide GFE and T1R1 / T1R3 residues are shown. Sesame umami peptides are tightly bound to the receptors by forming salt bridges, van der Waals forces, electrostatic interactions, conventional hydrogen bonds, carbon-hydrogen bonds, etc., among which the main interaction forces are hydrogen bonds and electrostatic interactions. ASN150, LYS996, ASP219 and ASP218 are the main docking sites of the three peptides with T1R1 / T1R3, indicating that peptide YMD, peptide RFT, and peptide GFE can interact with receptor T1R1 / T1R3, change the conformation of umami receptor T1R1 / T1R3, and thus enhance the transmission of umami signals. Subsequently, peptide YMD, peptide RFT, and peptide GFE were synthesized in vitro to verify their umami properties. Table 2 Molecular docking binding energy and interaction energy of sesame umami peptides and umami receptors T1R1 / T1R3 Serial number Peptide sequence CDOCKER_ENERGY CDOCKER_INTERACTION_ENERGY 1 YMD -66.2919 -50.3964 2 RFT -63.1804 -60.3132 3 GFE -61.8424 -35.9275 Example 3 Solid Phase Synthesis of Peptide GFE, Peptide YMD and Peptide RFT The sequences of potential umami peptides (YMD, GFE, RFT) with selected purity were synthesized by Fmoc solid phase method. The high performance liquid chromatography (HPLC) and mass spectrometry (MS) of the synthesized peptides are shown in Figure 4 shown. Depend on Figure 4 It can be seen that the purities of the synthetic peptides were all over 90% as shown by HPLC analysis and MS verification, and the purities of the solid phase synthesized peptides YMD, RFT and GFE were 98.553%, 96.378% and 90.098% respectively. Example 4 Sensory evaluation validation of peptide GFE, peptide YMD and peptide RFT The sensory evaluation panel consisted of 10 sensory evaluators (6 females and 4 males). The panel members were trained on five basic tastes (sour, sweet, bitter, salty and umami) before evaluating the samples. The reference standard solution was 1% sucrose solution (w / v), 0.35% salt (w / v), 0.35% sodium glutamate (w / v), 0.08% citric acid (w / v) and 1% L-leucine (w / v). Pure water was used to prepare three synthetic peptide solutions with a concentration of 1 mg / mL, and the pH was adjusted to 6.5. The panelists scored the five taste intensities of sweet, salty, bitter, sour and fresh of the three umami peptide samples. The reference standard solution was marked as 5 points, and the panelists recorded the taste intensity using a 10-point intensity scale (0 for no taste and 10 for strong taste). The triangle test method was used to determine the umami threshold of each synthetic peptide. The synthetic peptide solutions were gradually diluted in a 1:1 volume ratio and distributed to sensory officials for evaluation. The sensory officials were required to select samples with taste differences from 3 cups of solution (1 cup of sample solution and 2 cups of ultrapure water solution). The samples were randomly coded with three digits. The umami threshold of the synthetic peptide was the geometric mean of the individual thresholds of the panelists. The sensory evaluation results of peptide YMD, peptide RFT, and peptide GFE are as follows Figure 5 As shown by Figure 5 It can be seen that among the five basic tastes of synthetic peptides, umami is the most prominent, followed by sweetness, bitterness, sourness, and saltiness is the weakest. The umami values ​​of peptide YMD, peptide RFT, and peptide GFE are 3.875 points, 3.8 points, and 3 points, respectively. Among them, the docking energy of peptide GEF binding to umami receptors is the highest, which is consistent with the sensory score of the peptides. from Figure 5 It can be seen that all synthetic peptides show a certain sourness and bitterness, which may be due to impurities introduced during the synthesis of the peptides, but this has no effect on the umami taste. Studies have shown that sweet and umami amino acids are one of the key factors of umami peptides. From the perspective of amino acid composition, aspartic acid (D) and glutamic acid (E) are representative umami amino acids. In addition, sweet amino acids such as alanine (A), serine (S), glycine (G) and threonine (T) may also contribute to umami. The three umami peptides of the present invention all have umami or sweet amino acids, such as aspartic acid (D), threonine (T), glutamic acid (E), and glycine (G). The umami thresholds of the three peptides in aqueous solution are different, namely peptide YMD (0.074mM), peptide RFT (0.073mM), and peptide GFE (0.356mM), and the umami thresholds of peptide RFT and peptide YMD are lower. Example 5 Electronic tongue analysis validation of peptide GFE, peptide YMD and peptide RFT Electronic tongue analysis was performed on peptides GFE, YMD and RFT. A 1 mg / mL synthetic peptide solution was prepared. After adjusting the pH to 6.5 with sodium hydroxide solution, 65 mL of the sample solution was poured into the electronic tongue cup for testing. The sensor probe in the INSENT TS-5000Z taste sensing system was used for measurement. Three stable data were captured as the data for this electronic tongue experiment. Before the experiment, the instrument should be calibrated and the positive and negative sensors of the electronic tongue should be cleaned. As can be seen from Table 3, the umami value of peptide YMD is 15.72, the umami value of peptide GFE is 13.83, and the umami value of peptide RFT is 16.62, which shows that the analysis results of the electronic tongue are consistent with the results of the sensory evaluation, that is, the umami values ​​of peptide YMD and peptide RFT are higher, while the umami value of peptide GEF is lower. However, the three umami peptides were verified by the electronic tongue analysis and showed that they had umami characteristics. Table 3 Electronic tongue evaluation of synthetic umami peptides Peptide sequence sour Umami Salty Rich Value YMD -50.13 15.72 -1.28 -0.11 GFE -44.035 13.83 -0.88 -0.115 RFT -54.12 16.62 -0.37 0.07 Example 6 Freshness-enhancing effect of peptide GFE, peptide YMD and peptide RFT on monosodium glutamate The five synthetic peptides were prepared into 50 mL of 1 mg / mL solution, and sodium glutamate was added to make the concentration of the solution 0.35% to form a synthetic peptide sodium glutamate mixed solution with a synthetic peptide concentration of 1 mg / mL. The umami taste was scored according to the method of Example 4 and compared with the 0.35% sodium glutamate solution to determine its flavor enhancement effect. Depend on Figure 6 It can be seen that peptide GFE, peptide YMD and peptide RFT can all increase the umami taste intensity of monosodium glutamate, and the degree of improvement is peptide RFT, peptide GFE, and peptide YMD. Among them, peptide RFT and peptide GFE have a significant effect on the freshness-enhancing effect of monosodium glutamate, and the umami enhancement rate reaches 15-25%, indicating that peptide GFE, peptide YMD and peptide RFT can play a good role in enhancing freshness, and can be applied to umami agents and condiments, providing new raw material options for their development. Example 7 Determination of the Antioxidant Activity of Peptide GFE, Peptide YMD and Peptide RFT 10 mg of each lyophilized peptide was dissolved into a solution with a mass concentration of 1 mg / mL, and the DPPH free radical scavenging rate and ABTS free radical scavenging rate of the three umami peptides were measured respectively to evaluate the antioxidant activity of the three umami peptides. DPPH free radical scavenging rate determination method: take 2mL of the sample solution to be tested and 2mL of 0.1mmol DPPH anhydrous ethanol solution in turn, mix them and then stand them at room temperature in the dark for 30min, measure the absorbance A1 at a wavelength of 517nm, DPPH anhydrous ethanol solution plus distilled water as the blank group, its absorbance is A0, take the sample solution to be tested and anhydrous ethanol as the control group, its absorbance A2, the calculation formula is: DPPH inhibition rate = [1-(A1-A2) / A0]×100%; ABTS+ free radical scavenging rate determination method: Weigh a certain amount of ABTS+ powder and dissolve it in potassium persulfate solution, place it in the dark at room temperature for 12h-16h, dilute the stock solution with phosphate buffer (50mM, pH7.4) to obtain ABTS+ reaction solution, then dissolve each 10mg of lyophilized peptide into a solution with a mass concentration of 1mg / mL, take 1mL of sample solution and add it to 4mL of ABTS+ reaction solution, and then incubate the mixture in the dark at room temperature for 60min, and use an equal volume of phosphate buffer as a control. The absorbance of the control group and the experimental group at a wavelength of 734nm is respectively. The calculation method of ABTS+ free radical scavenging rate is as follows: scavenging rate = [1-(A1 / A2)]×100%. The results of the DPPH and ABTS free radical scavenging rates of the three umami peptides are shown in Table 4. Among them, peptide YMD has the strongest antioxidant activity and has DPPH and ABTS free radical scavenging activity, while peptide GFE and peptide RFT have DPPH free radical scavenging activity. Free radical scavenging is widely used to identify whether food products have antioxidant activity. The scavenging process of DPPH free radicals mainly involves hydrogen transfer (HAT); ABTS free radicals are a positively charged free radical, so it can obtain an electron from the antioxidant molecule to form a stable neutral molecule, so the scavenging of ABTS free radicals mainly involves the electron transfer (ET) mechanism. The different free radical scavenging activities of the three umami peptides are related to their amino acid sequence and structural differences. Peptide YMD has the highest antioxidant activity, which may be related to its free radical scavenging amino acids tyrosine (Y) and methionine (M). Therefore, peptide YMD, peptide RFT, and peptide GFE all have antioxidant activity and are multifunctional umami peptides with functional activity and flavor characteristics. Table 4 Analysis of free radical scavenging activity of umami peptides The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A sesame umami peptide with antioxidant activity, characterized in that: The sesame umami peptides include peptide GFE, peptide YMD and peptide RFT, wherein the amino acid sequence of peptide GFE is Gly-Phe-Glu, the amino acid sequence of peptide YMD is Tyr-Met-Asp, and the amino acid sequence of peptide RFT is Arg-Phe-Thr.

2. The sesame umami peptide with antioxidant activity according to claim 1, characterized in that: The umami threshold of the sesame umami peptide is 0.07-0.36 mmol / L.

3. The sesame umami peptide with antioxidant activity according to claim 1, characterized in that: The peptide GFE, peptide YMD and peptide RFT have the activity of scavenging DPPH free radicals, and the umami peptide YMD has the activity of scavenging ABTS free radicals.

4. A method for preparing a sesame umami peptide with antioxidant activity according to any one of claims 1 to 3, comprising the following steps: S1. Use BIOPEP-UWM tool to perform virtual enzymatic hydrolysis on sesame 11S globulin and sesame 2S globulin to obtain a set of theoretical peptide sequences; S2. Preliminary screening of the theoretical peptide sequence set, and secondary screening by duplicate analysis and PeptideRanker scoring; S3. Screening of potential umami peptides using iUmami-SCM, Umami_YYDS and Tastepeptides_DM models; S4. Evaluate the water solubility, allergenicity, stability and toxicity of potential umami peptides, and screen out umami peptides with good water solubility, no allergenicity, no toxicity and good stability; S5. Use molecular docking technology to simulate the binding of umami peptides to umami receptors T1R1 / T1R3 and screen candidate umami peptides; S6. Synthesize candidate umami peptides using a biological solid phase synthesis method; S7. Verification test: verify the candidate umami peptide to obtain the umami peptide.

5. A sesame protein hydrolysate, characterized in that: The sesame protein hydrolyzate comprises one or more of the peptide GFE, peptide YMD and peptide RFT described in claim 1.

6. Use of the sesame umami peptide with antioxidant activity according to any one of claims 1 to 4 in the preparation of foods, food additives and health products.

7. Use of the sesame umami peptide with antioxidant activity according to any one of claims 1 to 4 in improving the umami taste and flavor of food.

8. Use of the sesame protein hydrolyzate according to claim 5 in the preparation of foods, food additives and health products.

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