Umami peptide derived from euphausia superba and preparation method of umami peptide

Abstract

The invention relates to antarctic krill peptide with umami and an antarctic krill peptide mixture as well as a preparation method and application thereof. Specifically, the amino acid sequence of the euphausia superba peptide is shown as any one of SEQ ID NO: 1-5. The euphausia superba peptide mixture with delicate flavor is obtained by carrying out enzyme digestion treatment on an euphausia superba peptide solution by using incision enzyme, excision enzyme and freshness enhancing enzyme and harvesting supernate. Molecular docking simulation shows that the euphausia superba peptide disclosed by the invention can be combined with a delicate flavor receptor T1R1 / T1R3. The Antarctic krill peptide and the Antarctic krill peptide mixture can be used for development of umami seasonings, and a new idea is provided for development of marine seasonings.

Description

Technical Field

[0001] The present invention relates to the field of bioactive peptides, and in particular to an umami peptide derived from Antarctic krill and a preparation method thereof. Background Art

[0002] Umami, present in many foods, plays a significant role in their flavor. Umami peptides are a current research hotspot, likely due to their complex flavor and natural properties. Umami peptides are small molecule peptides that produce umami. They can be extracted from protein hydrolysates or synthesized from amino acids. They possess high nutritional value and flavor activity, and their umami-enhancing effects and flavor coordination surpass those of traditional flavor enhancers such as amino acids and flavor nucleotides. Umami peptides not only alter food flavor, enhancing its umami and kokumi notes, but can also synergize with other substances, such as salt and MSG, to enhance flavor, thereby reducing sodium intake.

[0003] Marine biological protein is considered to be an important biological source of umami peptides. Antarctic krill has a huge biomass and is considered to be one of the largest sources of animal protein in the world. It has a huge biomass and extremely high nutritional value. Research on Antarctic krill peptides has mostly focused on functional activities such as lowering uric acid, lowering blood pressure, and lowering lipids (CN202311480398.9, an Antarctic krill peptide with uric acid-lowering activity and its application; CN202410592380.6, Antarctic krill ACE inhibitory peptide VKGVFFGGALWLDAN and its application; CN202111011432.9, an Antarctic krill lipid-lowering peptide and its use in the treatment of hyperlipidemia), and research on Antarctic krill umami peptides is still in its infancy, and there are few reports on the mechanism of the umami presentation of its umami peptides.

[0004] Therefore, there is an urgent need in the art for an umami peptide derived from Antarctic krill and a preparation method thereof. Summary of the Invention

[0005] The present invention aims to provide an umami peptide derived from Antarctic krill and a preparation method thereof.

[0006] In a first aspect, the present invention provides an Antarctic krill peptide mixture having an umami taste, comprising a polypeptide having an amino acid sequence as shown in any one of SEQ ID NOs: 1 to 5.

[0007] In another preferred embodiment, in the Antarctic krill peptide mixture, the content of peptides with a molecular weight of 180 to 1500 Da is ≥50%, preferably ≥55%, and more preferably ≥60%.

[0008] In another preferred embodiment, the Antarctic krill peptide mixture is prepared by the following steps:

[0009] (s1) adding an endo-enzyme, an exo-enzyme and a flavor-enhancing enzyme to an Antarctic krill solution for an enzymatic hydrolysis reaction T1, wherein T1 is 1 to 5 hours, and the amount of the endo-enzyme, exo-enzyme and flavor-enhancing enzyme added is independently 0.1 to 1% (w / w); and

[0010] (s2) harvesting the supernatant to obtain an Antarctic krill peptide mixture with umami taste;

[0011] Wherein, the endonuclease is selected from the group consisting of neutral protease, alkaline protease, papain, composite protease, or a combination thereof;

[0012] The exonuclease is selected from the group consisting of aminopeptidase, flavor protease, or a combination thereof;

[0013] The flavor-enhancing enzyme is selected from the group consisting of asparaginase, glutaminase, or a combination thereof.

[0014] In another preferred embodiment, the endonuclease includes a composite protease; the exonuclease includes an aminopeptidase; and the flavor-enhancing enzyme includes asparaginase.

[0015] In another preferred embodiment, the material-liquid ratio of the Antarctic krill solution is 1:1-10, preferably 1:3-7, and more preferably 1:4-6.

[0016] In another preferred embodiment, in step (s1), the temperature of the enzymatic hydrolysis reaction is 50-70°C, preferably 50-65°C, more preferably 53-60°C, and most preferably 54-58°C.

[0017] In another preferred embodiment, in step (s1), the Antarctic krill solution is a defatted Antarctic krill solution.

[0018] In another preferred embodiment, the Antarctic krill solution is prepared from defatted Antarctic krill powder.

[0019] In another preferred embodiment, T1 is 1 to 4 hours, preferably 2 to 4 hours.

[0020] In another preferred embodiment, the added amount of the endonuclease, exonuclease and flavor-enhancing enzyme is independently 0.1-0.8% (w / w), preferably 0.1-0.5% (w / w), and more preferably 0.1-0.3% (w / w).

[0021] In another preferred embodiment, in step (s1), the enzymatic hydrolysis reaction is stopped by heating, preferably, heating at 85-95°C for 1-20 min, more preferably heating at 87-93°C for 5-20 min.

[0022] The second aspect of the present invention provides a method for preparing the Antarctic krill peptide mixture having umami taste as described in the first aspect of the present invention, comprising the steps of:

[0023] (s1) adding an endo-enzyme, an exo-enzyme and a flavor-enhancing enzyme to an Antarctic krill solution for an enzymatic hydrolysis reaction T1, wherein T1 is 1 to 5 hours, and the amount of the endo-enzyme, exo-enzyme and flavor-enhancing enzyme added is independently 0.1 to 1% (w / w); and

[0024] (s2) harvesting the supernatant to obtain an Antarctic krill peptide mixture with umami taste;

[0025] Wherein, the endonuclease is selected from the group consisting of neutral protease, alkaline protease, papain, composite protease, or a combination thereof;

[0026] The exonuclease is selected from the group consisting of aminopeptidase, Novozymes flavor protease, Angel flavor protease, or a combination thereof;

[0027] The flavor-enhancing enzyme is selected from the group consisting of asparaginase, glutaminase, or a combination thereof.

[0028] In another preferred embodiment, the endonuclease includes a composite protease; the exonuclease includes an aminopeptidase; and the flavor-enhancing enzyme includes asparaginase.

[0029] In another preferred embodiment, the material-liquid ratio of the Antarctic krill solution is 1:1-10, preferably 1:3-7, and more preferably 1:4-6.

[0030] In another preferred embodiment, in step (s1), the temperature of the enzymatic hydrolysis reaction is 50-70°C, preferably 50-65°C, more preferably 53-60°C, and most preferably 54-58°C.

[0031] In another preferred embodiment, in step (s1), the Antarctic krill solution is a defatted Antarctic krill solution.

[0032] In another preferred embodiment, the Antarctic krill solution is prepared from defatted Antarctic krill powder.

[0033] In another preferred embodiment, T1 is 1 to 4 hours, preferably 2 to 4 hours.

[0034] In another preferred embodiment, the added amount of the endonuclease, exonuclease and flavor-enhancing enzyme is independently 0.1-0.8% (w / w), preferably 0.1-0.5% (w / w), and more preferably 0.1-0.3% (w / w).

[0035] In another preferred embodiment, in step (s1), the enzymatic hydrolysis reaction is stopped by heating, preferably, heating at 85-95°C for 1-20 min, more preferably heating at 87-93°C for 5-20 min.

[0036] In a third aspect, the present invention provides an Antarctic krill peptide having an umami taste, wherein the Antarctic krill peptide is selected from the group consisting of:

[0037] (a) a polypeptide having an amino acid sequence shown in any one of SEQ ID NOs: 1 to 5;

[0038] (b) a polypeptide having ≥80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% homology (or identity) to the amino acid sequence of any one of SEQ ID NOs: 1-5, and the polypeptide has the biological function of any one of SEQ ID NOs: 1-13; or

[0039] (c) A derivative polypeptide formed by substituting, deleting or adding one or more (preferably 1 to 3, more preferably 1 to 2) amino acid residues of the amino acid sequence of any one of SEQ ID NOs: 1 to 5, and retaining the biological function of any one of SEQ ID NOs: 1 to 13.

[0040] In another preferred embodiment, the amino acid sequence of the Antarctic krill peptide is shown in any one of SEQ ID NOs: 1 to 5.

[0041] In another preferred embodiment, the Antarctic krill peptide binds to the umami taste receptor T1R1 / T1R3.

[0042] In another preferred embodiment, the binding energy between the Antarctic krill peptide and the umami taste receptor T1R1 / T1R3 is ≤-5 kal / mol, preferably ≤-5.5 kal / mol.

[0043] In another preferred embodiment, the Antarctic krill peptide is prepared by the following steps:

[0044] (s1) adding an endo-enzyme, an exo-enzyme and a flavor-enhancing enzyme to an Antarctic krill solution for an enzymatic hydrolysis reaction T1, wherein T1 is 1 to 5 hours, and the amount of the endo-enzyme, exo-enzyme and flavor-enhancing enzyme added is independently 0.1 to 1% (w / w); and

[0045] (s2) harvesting the supernatant to obtain Antarctic krill peptides with umami taste;

[0046] Wherein, the endonuclease is selected from the group consisting of neutral protease, alkaline protease, papain, composite protease, or a combination thereof;

[0047] The exonuclease is selected from the group consisting of aminopeptidase, Novozymes flavor protease, Angel flavor protease, or a combination thereof;

[0048] The flavor-enhancing enzyme is selected from the group consisting of asparaginase, glutaminase, or a combination thereof.

[0049] In another preferred embodiment, the step (s2) further comprises a step (s2a) of separating Antarctic krill peptides from the supernatant.

[0050] In a fourth aspect, the present invention provides a use of the Antarctic krill peptide mixture according to the first aspect of the present invention or the Antarctic krill peptide according to the third aspect of the present invention for preparing an umami seasoning.

[0051] In a fifth aspect, the present invention provides a seasoning comprising the Antarctic krill peptide mixture according to the first aspect of the present invention or the Antarctic krill peptide according to the third aspect of the present invention.

[0052] In another preferred embodiment, the seasoning includes umami seasoning.

[0053] It should be understood that within the scope of the present invention, the above-mentioned technical features of the present invention and the technical features described in detail below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be listed here one by one. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 The sensory scores, hydrolysis degree and peptide molecular weight distribution of Antarctic krill hydrolyzed by different enzymes are shown.

[0055] Figure 2 It shows that the addition of exoenzyme to Antarctic krill hydrolyzed improves the flavor of the hydrolyzate.

[0056] Figure 3 It shows that the addition of flavor-enhancing enzymes to the enzymatic hydrolysis of Antarctic krill improves the flavor of the hydrolysate.

[0057] Figure 4 The results of the effect of different enzymatic hydrolysis times on umami taste are shown.

[0058] Figure 5 The effect of endoenzyme addition on the enzymatic hydrolysis of Antarctic krill is shown.

[0059] Figure 6 The effect of exoenzyme addition on the enzymatic hydrolysis of Antarctic krill is shown.

[0060] Figure 7 The effect of the amount of added flavor-enhancing enzyme on the enzymatic hydrolysis of Antarctic krill is shown.

[0061] Figure 8 The three-dimensional structural model of the umami taste receptor T1R1 / T1R3 protein is shown.

[0062] Figure 9 Shown is the interaction of Antarctic krill peptides with umami taste receptors. DETAILED DESCRIPTION

[0063] After extensive and in-depth research, numerous experiments, and screening, the inventors unexpectedly discovered, for the first time, Antarctic krill peptides and Antarctic krill peptide mixtures with umami flavor. The amino acid sequences of the Antarctic krill peptides are shown in any one of SEQ ID NOs: 1-5. The Antarctic krill peptide solution was enzymatically digested with endo-, exo-, and flavor-enhancing enzymes, and the supernatant was harvested to obtain the umami-flavored Antarctic krill peptide mixture. Experiments have shown that the Antarctic krill peptide mixture prepared by the method of the present invention exhibits umami flavor. Molecular docking simulations have shown that the Antarctic krill peptides of the present invention can bind to the umami receptors T1R1 / T1R3. Therefore, the Antarctic krill peptides and Antarctic krill peptide mixtures of the present invention can be used in the development of umami seasonings. This is the basis for the completion of the present invention.

[0064] the term

[0065] In order to make the present invention easier to understand, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined in this article, all other technical and scientific terms used herein have the meanings commonly understood by those of ordinary skill in the art to which the present invention belongs. Before describing the present invention, it should be understood that the present invention is not limited to the specific methods and experimental conditions, because such methods and conditions can change. It should also be understood that the terms used herein are intended only to describe specific embodiments, and are not intended to be restrictive, and the scope of the present invention will be limited only by the appended claims.

[0066] As used herein, the term “comprise” or variations thereof such as “include” or “comprising”, etc., is understood to include the stated elements or components but does not exclude other elements or components.

[0067] The term "about" can refer to a value or composition that is within an acceptable error range for a particular value or composition as determined by one of ordinary skill in the art, which will depend in part on how the value or composition is measured or determined. For example, as used herein, the expression "about 100" includes all values ​​between 99 and 101 (e.g., 99.1, 99.2, 99.3, 99.4, etc.).

[0068] As used herein, unless otherwise indicated, any concentration range, percentage range, ratio range, or integer range should be understood to include the value of any integer within the range and, where appropriate, fractional values ​​thereof (e.g., tenths and hundredths of an integer).

[0069] As used herein, the term "and / or" refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0070] "Identity" refers to the matching of sequences between two polypeptides or between two nucleic acids. "Identity" represents the percentage of residues that are identical between the polypeptide or nucleic acid sequences, and is calculated based on the total number of residues determined by the type of mutation. Mutation types include insertions (extensions) at either or both ends of the sequence, deletions (truncations) at either or both ends of the sequence, substitutions / alternations of one or more amino acids / nucleotides, insertions within the sequence, and deletions within the sequence.

[0071] Taking a polypeptide sequence as an example, if the mutation type is one or more of the following: substitution / replacement of one or more amino acids / nucleotides, insertion within the sequence, and deletion within the sequence, the total number of residues is calculated based on the larger of the compared molecules. If the mutation type also includes insertion (extension) at either or both ends of the sequence or deletion (truncation) at either or both ends of the sequence, the number of amino acids inserted or deleted at either or both ends (e.g., the number of insertions or deletions at both ends is less than 20) is not counted in the total number of residues. When calculating the percentage of identity, the sequences being compared are aligned in a manner that produces the maximum match between the sequences, and gaps in the alignment (if any) are resolved by a specific algorithm.

[0072] Antarctic krill

[0073] Defatted Antarctic krill meal is rich in umami amino acids, such as glutamic acid (Glu) and aspartic acid (Asp), essential for the production of umami peptides. These two amino acids are acidic, and umami peptides typically contain one or two Glu and Asp acidic groups. Furthermore, the proportion of Glu and Asp in defatted Antarctic krill hydrolysate is higher than in chicken broth hydrolysate, which is widely recognized for its strong umami flavor. Therefore, Antarctic krill is an ideal raw material for the production of umami peptides.

[0074] Umami taste receptors T1R1 / T1R3

[0075] The umami receptor T1R1 / T1R3 is a heterodimeric taste receptor in the G protein-coupled receptor (GPCR) family. It consists of two subunits, T1R1 and T1R3, non-covalently bound to form a functional complex. It is primarily expressed on the surface of oral taste buds and some enteroendocrine cells. This receptor system is the core molecular basis for the human body's perception of umami glutamate (such as monosodium L-glutamate / MSG) and nucleotide umami enhancers (such as IMP and GMP). Its activation triggers the "umami" signaling pathway.

[0076] Complex protease

[0077] The composite protease used in the present invention is an endoenzyme, comprising 5 to 15 parts by weight of a protease (neutral, CAS no. 9080-56-2) and 0.5 to 5 parts by weight of a protease (subtilisin, CAS no. 9014-01-1); preferably, 7 to 12 parts by weight of a protease (neutral, CAS no. 9080-56-2) and 1 to 3 parts by weight of a protease (subtilisin, CAS no. 9014-01-1); more preferably, 9 parts by weight of a protease (neutral, CAS no. 9080-56-2) and 2 parts by weight of a protease (subtilisin, CAS no. 9014-01-1).

[0078] Antarctic krill peptide mixture of the present invention

[0079] The Antarctic krill peptide mixture of the present invention has an umami taste and comprises a polypeptide having an amino acid sequence as shown in any one of SEQ ID NOs: 1 to 5. The Antarctic krill peptide mixture is prepared by the following steps:

[0080] (s1) adding an endo-enzyme, an exo-enzyme and a flavor-enhancing enzyme to an Antarctic krill solution for an enzymatic hydrolysis reaction T1, wherein T1 is 1 to 5 hours, and the amount of the endo-enzyme, exo-enzyme and flavor-enhancing enzyme added is independently 0.1 to 1% (w / w); and

[0081] (s2) harvesting the supernatant to obtain an Antarctic krill peptide mixture with umami taste;

[0082] Wherein, the endonuclease is selected from the group consisting of neutral protease, alkaline protease, papain, composite protease, or a combination thereof;

[0083] The exonuclease is selected from the group consisting of aminopeptidase, Novozymes flavor protease, Angel flavor protease, or a combination thereof;

[0084] The flavor-enhancing enzyme is selected from the group consisting of asparaginase, glutaminase, or a combination thereof.

[0085] Antarctic krill peptide of the present invention

[0086] The Antarctic krill peptide of the present invention is selected from the following group:

[0087] (a) a polypeptide having an amino acid sequence shown in any one of SEQ ID NOs: 1 to 5;

[0088] (b) a polypeptide having ≥80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% homology (or identity) to the amino acid sequence of any one of SEQ ID NOs: 1-5, and the polypeptide has the biological function of any one of SEQ ID NOs: 1-13; or

[0089] (c) A derivative polypeptide formed by substituting, deleting or adding one or more (preferably 1 to 3, more preferably 1 to 2) amino acid residues of the amino acid sequence of any one of SEQ ID NOs: 1 to 5, and retaining the biological function of any one of SEQ ID NOs: 1 to 13.

[0090] Those skilled in the art will appreciate examples and embodiments of conservative amino acid substitutions. Specifically, an amino acid residue can be substituted with another amino acid residue belonging to the same group as the site to be substituted, i.e., a non-polar amino acid residue can be substituted for another non-polar amino acid residue, a polar uncharged amino acid residue can be substituted for another polar uncharged amino acid residue, a basic amino acid residue can be substituted for another basic amino acid residue, and an acidic amino acid residue can be substituted for another acidic amino acid residue. Such substituted amino acid residues may or may not be encoded by the genetic code. Conservative substitutions, in which one amino acid is replaced by another amino acid belonging to the same group, fall within the scope of the present invention as long as the substitution does not inactivate the biological activity of the polypeptide. Therefore, the polypeptides of the present invention may comprise one or more conservative substitutions in the amino acid sequence, preferably generated by substitution according to Table 1. In addition, the present invention also encompasses polypeptides that further comprise one or more other non-conservative substitutions, as long as the non-conservative substitutions do not significantly affect the desired function and biological activity of the polypeptides of the present invention.

[0091] Conservative amino acid replacement can be carried out at one or more predicted non-essential amino acid residues.A "non-essential" amino acid residue is an amino acid residue that can be changed (deleted, substituted or replaced) without changing biological activity, while an "essential" amino acid residue is required for biological activity.A "conservative amino acid replacement" is a replacement in which an amino acid residue is replaced by an amino acid residue with a similar side chain.Amino acid replacement can be carried out in the non-conserved region of a Cas enzyme.In general, such replacements are not carried out on conserved amino acid residues, or on amino acid residues located within a conserved motif, where such residues are required for protein activity.

[0092] In certain embodiments, selected groups of amino acids that are considered conservative substitutions for each other are:

[0093]

[0094]

[0095] The Antarctic krill peptide of the present invention can be artificially synthesized by chemical synthesis, biosynthesis, etc., preferably solid phase synthesis, liquid phase synthesis, stepwise synthesis, enzymatic synthesis, gene expression, artificial grafting and enzymatic hydrolysis.

[0096] Method of the present invention

[0097] The method of the present invention refers to a method for preparing the Antarctic krill peptide or Antarctic krill peptide mixture of the present invention, comprising the steps of:

[0098] (s1) adding an endo-enzyme, an exo-enzyme and a flavor-enhancing enzyme to an Antarctic krill solution for an enzymatic hydrolysis reaction T1, wherein T1 is 1 to 5 hours, and the amount of the endo-enzyme, exo-enzyme and flavor-enhancing enzyme added is independently 0.1 to 1% (w / w); and

[0099] (s2) harvesting the supernatant to obtain an Antarctic krill peptide mixture or Antarctic krill peptide with umami taste;

[0100] Wherein, the endonuclease is selected from the group consisting of neutral protease, alkaline protease, papain, composite protease, or a combination thereof;

[0101] The exonuclease is selected from the group consisting of aminopeptidase, flavor protease, or a combination thereof;

[0102] The flavor-enhancing enzyme is selected from the group consisting of asparaginase, glutaminase, or a combination thereof.

[0103] In a preferred embodiment, in step (s1), the temperature of the enzymatic hydrolysis reaction is 50-70°C, preferably 50-65°C, more preferably 53-60°C, and most preferably 54-58°C.

[0104] In a preferred embodiment, the added amount of the endonuclease, exonuclease and flavor-enhancing enzyme is independently 0.1-0.8%, preferably 0.1-0.5%, and more preferably 0.1-0.3%.

[0105] In another preferred embodiment, in step (s1), the enzymatic hydrolysis reaction is stopped by heating, preferably, heating at 85-95°C for 1-20 min, more preferably heating at 87-93°C for 5-20 min.

[0106] In a preferred embodiment, the flavor protease is a combination of a polypeptide produced by fermentation of an Aspergillus oryzae strain and an endoprotease produced by fermentation of Bacillus subtilis. In a preferred embodiment, the flavor protease comprises 3 to 10 parts by weight of aminopeptidase (CAS no. 9001-60-1); preferably 5 to 8 parts by weight of aminopeptidase (CAS no. 9001-60-1); and more preferably 5 parts by weight of aminopeptidase (CAS no. 9001-60-1). A preferred flavor protease is Angel Flavor Protease or Novozymes Flavor Protease.

[0107] The main advantages of the present invention include:

[0108] 1. The Antarctic krill peptide or Antarctic krill peptide mixture prepared by the method of the present invention has a strong umami taste and can be used for the development of umami seasonings, providing a new idea for the development of marine seasonings.

[0109] 2. The interaction mechanism between the Antarctic krill peptide or the peptides in the Antarctic krill peptide mixture of the present invention and the umami receptor T1R1 / T1R3 was elucidated by computer simulation technology, thereby screening out key peptides with potential umami taste.

[0110] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the present invention. The experimental methods in the following examples, for which specific conditions are not specified, are generally performed under conventional conditions, such as those described in Sambrook et al., Molecular Cloning: A Laboratory Manual (New York: Cold Spring Harbor Laboratory Press, 1989), or according to the conditions recommended by the manufacturer. Unless otherwise stated, percentages and parts are calculated by weight.

[0111] 1. Materials

[0112] Defatted Antarctic krill meal (Luhua), neutral protease (Neutrase 0.8L, Novozymes), alkaline protease (Alcalase 2.4L FG, Novozymes), papain (Papain, Angel Yeast), complex protease (Protamex1.6, Novozymes), aminopeptidase (Protana Prime, Novozymes), flavor protease (Flavourzyme 500MG, Novozymes), flavor protease (FF104AN, Angel Yeast), asparaginase (Acrylaway L, Novozymes), glutaminase (Protana Uboost, Novozymes), 0.1mol / L sodium hydroxide solution, 0.1mol / L hydrochloric acid.

[0113] 2. Methods

[0114] 2.1 Preparation method of Antarctic krill umami peptide

[0115] Weigh a predetermined amount of defatted Antarctic krill meal and add a predetermined amount of pure water according to the material-liquid ratio, stirring thoroughly until the pH reaches a natural level. Add a predetermined amount of enzyme and allow the mixture to hydrolyze in a constant-temperature water bath at a specific temperature for a predetermined period of time. Inactivate the enzyme in a 90°C water bath for 15 minutes. After cooling to room temperature, centrifuge at 10,000 rpm for 15 minutes. Collect the supernatant, which is the enzymatic hydrolyzate containing the polypeptides.

[0116] 2.2 Single-factor experiment

[0117] 2.2.1 Determination of enzyme types

[0118] (1) Determination of endonuclease type

[0119] Neutral protease, alkaline protease, papain, and a combined protease were selected to hydrolyze defatted Antarctic krill meal under their optimal pH and temperature conditions: 7.0 / 50°C, 9.0 / 70°C, 7.0 / 55°C, and natural / 55°C, respectively. The enzyme dosage was 0.1%, the material-liquid ratio was 1:5, the hydrolysis time was 3 hours, the enzyme was inactivated for 15 minutes, and the supernatant containing peptides was obtained by centrifugation at 10,000 rpm for 15 minutes. The optimal endonuclease was selected based on the degree of hydrolysis, sensory evaluation, and peptide molecular weight distribution.

[0120] (2) Determination of exonuclease type

[0121] Defatted Antarctic krill meal was enzymatically hydrolyzed in the presence of an optimal endoenzyme using aminopeptidase, Novozymes flavor protease, and Angel flavor protease. The optimal endoenzyme addition level was 0.1%, the exoenzyme addition level was 0.1%, the material-to-liquid ratio was 1:5, the pH was natural, the hydrolysis temperature was 55°C, the hydrolysis time was 3 hours, the enzyme was inactivated for 15 minutes, and the supernatant was collected to obtain the peptide-containing hydrolyzate. The optimal exoenzyme was selected based on the degree of hydrolysis, sensory evaluation, and peptide molecular weight distribution.

[0122] (3) Determination of the type of freshness-enhancing enzyme

[0123] Defatted Antarctic krill meal was enzymatically hydrolyzed with asparaginase and glutaminase in the presence of the optimal endo- and exo-enzymes. The optimal endo- and exo-enzyme addition levels were 0.1%, and the flavor-enhancing enzyme was added at 0.1%. The material-to-liquid ratio was 1:5, the pH was natural, the hydrolysis temperature was 55°C, the hydrolysis time was 3 hours, the enzyme was inactivated for 15 minutes, and the supernatant was collected to obtain the polypeptide-containing enzymatic hydrolyzate. The optimal flavor-enhancing enzyme was selected based on the degree of hydrolysis, sensory evaluation, and peptide molecular weight distribution.

[0124] 2.2.2 Effect of enzymatic hydrolysis time on enzymatic hydrolysis effect

[0125] Under the conditions of optimal compound enzyme addition amount of 0.1%, natural pH, hydrolysis temperature of 55℃, and material-liquid ratio of 1:5, enzymatic hydrolysis was carried out at different hydrolysis times (2.5h, 3h, 3.5h, 4h), and the optimal hydrolysis time was selected based on the hydrolysis degree, sensory evaluation and peptide molecular weight distribution.

[0126] 2.2.3 Effect of enzyme addition on enzymatic hydrolysis effect

[0127] (1) Effect of optimal endonuclease addition on enzymatic hydrolysis effect

[0128] Under the conditions of natural pH, hydrolysis temperature of 55°C, hydrolysis time of 3h, material-liquid ratio of 1:5, and optimal exonuclease and flavor-enhancing enzyme addition amount of 0.1%, enzymatic hydrolysis was carried out at different optimal endonuclease addition amounts (0.1%, 0.15%, 0.2%, 0.25%, 0.3%), and the optimal endonuclease addition amount was determined based on the degree of hydrolysis, sensory evaluation and peptide molecular weight distribution.

[0129] (2) Effect of optimal exonuclease addition on enzymatic hydrolysis effect

[0130] Under the conditions of natural pH, hydrolysis temperature of 55°C, hydrolysis time of 3h, material-liquid ratio of 1:5, optimal addition amount of optimal endonuclease and optimal addition amount of freshness-enhancing enzyme of 0.1%, enzymatic hydrolysis was carried out at different optimal exonuclease addition amounts (0.1%, 0.15%, 0.2%, 0.25%), and the optimal exonuclease addition amount was determined based on the degree of hydrolysis, sensory evaluation and peptide molecular weight distribution.

[0131] (3) Effect of the optimal amount of freshness-enhancing enzyme added on enzymatic hydrolysis effect

[0132] Under the optimal conditions of natural pH, hydrolysis temperature of 55℃, hydrolysis time of 3h, material-liquid ratio of 1:5, and optimal endonuclease and exonuclease, enzymatic hydrolysis was carried out at different optimal addition amounts of the flavor-enhancing enzyme (0.1%, 0.15%, 0.2%, 0.25%, 0.3%), and the optimal addition amount of the flavor-enhancing enzyme was determined based on the degree of hydrolysis, sensory evaluation and peptide molecular weight distribution.

[0133] 2.4 Orthogonal experiment

[0134] According to the results of the single factor experiment, under the conditions that the addition amount of the optimal exonuclease and the flavor enhancing enzyme were the best, the three factors of the optimal endonuclease addition amount, the material-liquid ratio and the enzymatic hydrolysis time were selected as the research objects for L9(3 4 ) Orthogonal experiment, with hydrolysis degree and sensory score as indicators, the experimental design is shown in Table 1.

[0135] Table 1 Factor levels of enzymatic hydrolysis orthogonal test

[0136]

[0137] 2.4 Peptide identification using liquid chromatography-mass spectrometry

[0138] The hydrolysate prepared using the optimized enzymatic hydrolysis process was desalted, and all peptides in the Antarctic krill hydrolysate were analyzed by mass spectrometry using a high-resolution mass spectrometer (Orbitrap Exploris 480, ThermoScientific). Mobile phases A and B were 0.1% formic acid in H₂O and 80% ACN in H₂O, respectively. The column used was a C₁8 column. Data were acquired in DDA mode with positive ion detection, a spray voltage of 1900 V, an ion transfer tube temperature of 300°C, and a 60-min acquisition time. Proteome Discover software was used for database search; database matching parameters are shown in Table 2.

[0139] Table 2 Database matching parameter settings

[0140]

[0141] 2.5 Screening of potential umami peptides

[0142] The identified peptides were sequentially imported into iUmami-SCM (https: / / camt.pythonanywhere.com / iUmami-SCM), Tastepeptides_DM (http: / / tastepeptides-meta.com / TPDM), and UMPred-FRL (https: / / pmlabstack.pythonanywhere.com / UMPred-FRL) for umami and bitterness prediction. The three tools were used together to screen the candidate peptides for potential umami peptides.

[0143] ToxinPred (https: / / webs.iiitd.edu.in / raghava / toxinpred / multi_submit.php) and Innovagen (http: / / www.innovagen.com / ) were used to predict the toxicity and water solubility of the screened peptides, and Expasy (https: / / web.expasy.org / protparam / ) was used to predict the hydrophilicity. Toxic and poorly water-soluble peptides were excluded from subsequent screening.

[0144] 2.6 Homology Modeling

[0145] Because the crystal structure of the umami taste receptors T1R1 / T1R3 has not yet been determined, homology modeling was performed to generate a 3D structure. The amino acid sequences of the umami taste receptors T1R1 / T1R3 were obtained from Uniprot (https: / / www.uniprot.org / ), with accession numbers Q7RTX1 and Q7RTX0. Using the metabotropic glutamate receptor as a template (PDB ID: 1EWK), homology modeling of T1R1 / T1R3 was performed using the Swiss Model (https: / / swissmodel.expasy.org / ) based on sequence homology between the receptor and the template. To further investigate and confirm the reliability of the homology model, the constructed model was imported into the evaluation software SAVES v6.0 (https: / / saves.mbi.ucla.edu / ). The protein conformational plausibility was evaluated using Ramachandran plots and Verify 3D. Once verified, the model was ready for molecular docking.

[0146] 2.7 Molecular docking

[0147] The planar structures of the umami peptides were drawn using Chem Draw 19.0 and then imported into Chem 3D 19.0 to construct their 3D structures. The structures of each peptide were optimized by calculating their minimum energy. Molecular docking of the peptides with T1R1 / T1R3 was performed using Autodock Vina, and the optimal structure resulting from docking with T1R1 / T1R3 was saved. For each umami peptide, the docking result with the lowest docking energy was selected for subsequent analysis. Monosodium glutamate (MSG) was used as a positive control. The docking results were visualized and analyzed using PyMol and DiscoveryStudio 2019 Client.

[0148] 2.8 Prediction of umami threshold of potential umami peptides

[0149] Potential umami peptides with lower binding energies than MSG were imported into Umami IP (http: / / tastepeptides-meta.com / Umami_IP) to predict their umami thresholds. Peptides with lower umami thresholds were selected for further investigation. The screening results were compared with peptides reported in the BIOPEP-UMW sensory peptide library.

[0150] 3. Detection Methods

[0151] 3.1 Hydrolysis degree detection:

[0152] The content of free amino acid nitrogen in the enzymatic hydrolysate was determined by formaldehyde titration, and the total nitrogen content of the raw material was determined by Kjeldahl method. The degree of hydrolysis is the percentage of amino acid nitrogen content to total nitrogen content.

[0153] 3.2 Peptide molecular weight distribution determination

[0154] Established in accordance with Appendix A of GB / T 22729-2008, the content of PEG was determined by high performance gel filtration chromatography.

[0155] 3.3 Sensory evaluation

[0156] MSG solution was used as the umami standard, and its concentrations of 0.21%, 0.35%, 0.49%, and 0.63% were set to 3, 6, 7, and 9 points for umami evaluation, respectively.

[0157] 4. Results and Discussion

[0158] 4.1 Single-factor experiment

[0159] 4.1.1 Determination of enzyme type

[0160] like Figure 1 As shown, alkaline protease had the highest degree of hydrolysis, followed by composite protease; composite protease had the highest sensory score, while alkaline protease had the lowest. Studies have shown that umami peptides typically have a molecular weight less than 3000 Da. Peptides with smaller molecular weights, particularly those less than 1500 Da, exhibit a stronger umami flavor. Peptides less than 180 Da are generally considered amino acids. In terms of peptide molecular weight distribution, alkaline protease was most abundant in the 180-1500 Da range, while peptides with less than 180 Da were least abundant, followed by composite protease. Overall, composite protease demonstrated the best enzymatic hydrolysis and was used in subsequent experiments.

[0161] Add exoenzyme to improve the flavor of the enzymatic hydrolysate based on the presence of compound protease, such as Figure 2 As shown, aminopeptidase had the highest degree of hydrolysis and sensory scores. Looking at the peptide molecular weight distribution, although Angel Flavor Protease was most abundant in the 180-1500 Da range, it had the lowest sensory score. Aminopeptidase with a molecular weight less than 180 Da accounted for the highest proportion, likely due to the production of more umami amino acids. Therefore, based on a comprehensive evaluation, aminopeptidase was selected for subsequent experiments.

[0162] Adding flavor-enhancing enzymes to increase the flavor of the enzymatic hydrolysate based on the presence of compound proteases and aminopeptidases, such as Figure 3 As shown in the figure, asparaginase has the highest sensory score, glutaminase has a high degree of hydrolysis but its freshness-enhancing effect is not as good as asparaginase. Therefore, asparaginase is selected as the optimal freshness-enhancing enzyme for the purpose of freshness enhancement.

[0163] 4.1.2 Effect of enzymatic hydrolysis time on enzymatic hydrolysis effect

[0164] like Figure 4As shown, the degree of hydrolysis slowly increases with increasing hydrolysis time before leveling off, likely due to near-complete enzyme reaction at 3 hours. The sensory score was highest when the hydrolysis time was 3 hours. As the hydrolysis time increased, the hydrolyzate developed a bitter taste, resulting in a downward trend in sensory scores. The molecular weight distribution of peptides differed little between hydrolysis times, so 3 hours was selected as the optimal hydrolysis time based on both umami scores and time efficiency.

[0165] 4.1.3 Effect of enzyme addition on enzymatic hydrolysis effect

[0166] Under the conditions of optimal material-liquid ratio and enzymatic hydrolysis time, the addition amount of different optimal enzymes was explored. Figure 5 As shown, the degree of hydrolysis gradually increases with increasing compound protease (the optimal endonuclease). The sensory score of the enzymatic hydrolyzate is highest when the compound protease addition level is 0.25%. In terms of peptide molecular weight distribution, a higher compound protease addition level leads to lower amino acid content (<180 Da) and higher peptide content in the 180-1500 Da range. Therefore, the optimal enzymatic hydrolysis effect is achieved when the compound protease addition level is 0.25%.

[0167] On this basis, the addition amount of aminopeptidase (optimal exonuclease) was explored. As the amount of aminopeptidase added increased, the degree of hydrolysis slowly increased; when the amount of aminopeptidase added was 0.15%, the sensory score of the enzymatic hydrolyzate was the highest ( Figure 6 The molecular weight distribution of peptides in the hydrolyzed solution with different exonuclease amounts is not much different ( Figure 6 Middle B), after comprehensive comparison, 0.15% was selected as the optimal exonuclease addition amount.

[0168] Finally, the amount of enzyme added was explored, such as Figure 7 The addition of asparaginase (the optimal flavor-enhancing enzyme) had little effect on the degree of hydrolysis, and sensory scores generally showed an upward trend. At 0.2% asparaginase, the distribution of <180 Da was minimal. Therefore, based on a comprehensive assessment of economic benefits, 0.2% was selected as the optimal flavor-enhancing enzyme addition level.

[0169] 4.2 Orthogonal experiment

[0170] Based on the results of the single-factor experiment, three factors, namely, the amount of compound protease (optimal endonuclease), enzymatic hydrolysis time, and material-liquid ratio, were selected as research objects for a three-factor three-level orthogonal experiment. The experimental results are shown in Table 3.

[0171] The orthogonal test results show that the hydrolysis degree trend is consistent with the single-factor experiment, showing that the hydrolysis degree increases with increasing compound protease dosage, prolonged enzymatic hydrolysis time, and increased material-to-liquid ratio. Sensory analysis shows that the highest sensory score was achieved when all factors were at level 2. For both the hydrolysis degree and sensory scores, the order of influencing factors was C > B > A, indicating that the material-to-liquid ratio was the most important factor influencing the enzymatic hydrolysis effect. Based on a comprehensive assessment of enzymatic hydrolysis effect and economic efficiency, the optimal enzymatic hydrolysis conditions were determined to be: a material-to-liquid ratio of 1:5, a hydrolysis time of 3 hours, a compound protease dosage of 0.25%, a Protana Prime enzyme dosage of 0.15%, and an asparaginase dosage of 0.2%.

[0172] Table 3 Results of enzymatic hydrolysis orthogonal test

[0173]

[0174] 4.3 Identification and virtual screening of potential umami peptides

[0175] The enzymatic hydrolysate prepared using the optimal process was identified by mass spectrometry and compared with Antarctic krill sequences in the Uniprot database, yielding 38 peptides. Umami and bitterness predictions were performed on these identified peptides. Umami scores >588 were considered umami in the iUmami-SCM tool; Umami scores >0.5 and bitterness scores <0.5 in the TPDM tool were considered bitter; and Umami scores >0.5 in the UMPred-FRL tool were considered umami. Peptides predicted to have umami flavor by all three tools and to be non-bitter in the TPDM tool were then used for toxicity, water solubility, and hydrophilicity predictions. A Gravy score <0 indicated hydrophilicity.

[0176] 4.4 Homology Modeling of Umami Taste Receptors T1R1 / T1R3

[0177] The results of the three-dimensional structure construction of the umami receptor T1R1 / T1R3 protein are as follows Figure 8 In middle A, T1R1 is on the left and T1R3 is on the right. According to the Ramachandran Plot results ( Figure 8 In B), 99.2% of the amino acid residues are located in reasonable regions (87.3% in the most favorable region, 10.5% in the additional allowed region, and 1.4% in the relaxed region). According to the 90% critical principle, the conformation is reasonable. According to the Verify 3D results ( Figure 8 In Figure C), 81.37% of the residues had an average 3D / 1D score ≥ 0.1, indicating a reasonable conformation based on the 80% critical rule. In summary, the umami taste receptor model constructed by homology modeling can be used for molecular docking.

[0178] 4.5 Molecular docking and prediction of umami threshold of potential umami peptides

[0179] Molecular docking is a commonly used molecular modeling method that can be used to predict the binding sites and intermolecular interaction patterns between umami peptides and umami receptor proteins. T1R1 / T1R3 is a heterodimer. The crystal structure of T1R1 shows a closed conformation, while that of T1R3 shows an open conformation, possessing a receptor binding site large enough to accommodate long-chain umami peptides. The peptides predicted and screened were docked with the umami receptors T1R1 / T1R3 using Autodock Vina. Using monosodium glutamate (MSG) as a positive control, the peptides were virtually screened based on their binding energies. Binding energies indicate the affinity between umami peptides and taste receptors. Studies have shown that lower binding energies indicate greater structural stability between the umami peptide and receptor, potentially enhancing umami production. Peptides with docking binding energies lower than that of MSG (-5.7 kcal / mol) and an umami threshold value of <2 are likely to possess stronger umami potential.

[0180] 4.6 Analysis of the Umami Fragments of Potential Umami Peptides and Their Interactions with T1R1 / T1R3

[0181] Through the above screening, five potential umami peptides were ultimately identified (see Table 4). Analysis of the umami-active fragments and umami-fragment frequencies of these five peptides in the BIOPEP-UWM database revealed that EDELVNEKE had the highest umami-active fragment frequency, reaching 0.889, followed by EEDLERSEE (0.667) and EEDQLRII (0.625). These umami-active fragments further predicted the umami potential of these peptides. Furthermore, none of these five peptides were included in the BIOPEP-UWM database, confirming their novelty.

[0182] Table 4 Analysis of umami fragments of potential umami peptides

[0183]

[0184] The umami receptor T1R1 subunit mainly promotes the recognition of umami compounds, and the T1R3 subunit is responsible for other auxiliary functions. MSG binds to T1R1. The closer the binding area of ​​the umami peptide to the umami receptor is to the MSG binding area, the stronger its potential umami intensity. Figure 9As shown, the five umami peptides all docked well within the T1R1 / T1R3 binding region. With the exception of NEEDQLRII, the remaining peptides docked near the T1R1 active site, demonstrating their strong umami potential. As shown in the 2D docking diagram, the umami peptides formed stable complexes with T1R1 / T1R3 through conventional hydrogen bonds, carbon-hydrogen bonds, salt bridges, attractive charges, and π-alkyl bonds (green represents conventional hydrogen bonds, light green represents carbon-hydrogen bonds, orange represents salt bridges / attractive charges, and purple represents π-alkyl bonds / alkyl bonds). This study revealed that non-covalent interactions (hydrogen bonds, electrostatic interactions, and hydrophobic interactions) play a primary role in the binding of umami peptides to umami receptors. Table 5 shows the binding sites and extent of the potential umami peptides to the umami receptors T1R1 / T1R3. As shown in the table, Arg54, Ser107, Asp108, Ser109, Ala110, Asn150, Ser217, Asp218, Phe247, Ala249, Gln250, Lys155, and Glu178 are key binding sites, most of which have been previously reported. Among them, Arg54, Asp108, Asn150, Lys155, Gln250, and Glu178 are most frequently found in umami peptide binding. Therefore, these six amino acids are key amino acid residues for the recognition and binding of umami peptides by the umami receptors T1R1 / T1R3. Studies have found that the amino acid residues that bind to umami peptides are mostly polar amino acids such as Asp, Gln, Ser, and Asn. These amino acids bind to umami peptides through hydrogen bonds, facilitating the formation of stable complexes between the umami receptors and umami peptides.

[0185] Table 5 Docking sites and interaction forces between potential umami peptides and umami receptors T1R1 / T1R3

[0186]

[0187]

[0188] Note: “+” indicates the degree of binding between the peptide and the receptor.

[0189] Enzymatic hydrolysis is the main method for preparing umami peptides. After enzymatic hydrolysis, the enzymatic hydrolysate is separated and purified by nanofiltration, ultrafiltration, gel filtration chromatography, etc., and finally the obtained peptides are identified by mass spectrometry. In the existing invention patent (CN202211395747.2, an umami peptide and its preparation method and application), the amount of enzyme added for the enzymatic hydrolysis of defatted Antarctic krill powder is relatively high, which is obviously not conducive to the cost control of the enzymatic hydrolysis process. Although traditional screening methods are widely used, the screening work is mechanically cumbersome, the purification equipment is relatively expensive, and the experimental cycle is relatively long, which limits the discovery and research of new umami peptides. Therefore, computer-assisted analysis technology has gradually become a powerful tool for umami peptide research in recent years and has broad potential research space. Molecular docking and machine learning are considered to be high-throughput and rapid technologies that can be used to preliminarily screen umami peptides from established peptide libraries.

[0190] 5. Conclusion

[0191] This study established an optimal preparation process for Antarctic krill hydrolysate, specifying the following parameters: a material-liquid ratio of 1:5, a hydrolysis time of 3 hours, a compound protease level of 0.25%, a Protana Prime enzyme level of 0.15%, and an asparaginase level of 0.2%. Five novel umami peptides were identified from the hydrolysate using virtual screening. Molecular docking results revealed that the binding of umami peptides to the umami receptors T1R1 / T1R3 primarily involves hydrogen bonding, electrostatic interactions, and hydrophobic interactions. Amino acid residues Arg54, Asp108, Asn150, Lys155, Gln250, and Glu178 are crucial for T1R1 / T1R3 recognition of umami peptides. This research enriches the marine umami peptide library, enhances the application and economic value of Antarctic krill, and provides a theoretical basis for the flavor-producing mechanism of Antarctic krill umami peptides.

[0192] All documents mentioned in this application are incorporated herein by reference, just as if each document were incorporated herein by reference individually. It should also be understood that after reading the above teachings of the present invention, those skilled in the art may make various changes or modifications to the present invention, and that such equivalents also fall within the scope of the claims appended hereto.

Claims

1. An Antarctic krill peptide mixture with umami taste, characterized in that: A polypeptide comprising an amino acid sequence as shown in any one of SEQ ID NOs: 1 to 5.

2. The Antarctic krill peptide mixture according to claim 1, characterized in that The Antarctic krill peptide mixture is prepared by the following steps: (s1) adding an endo-enzyme, an exo-enzyme and a flavor-enhancing enzyme to an Antarctic krill solution for an enzymatic hydrolysis reaction T1, wherein T1 is 1 to 5 hours, and the amount of the endo-enzyme, exo-enzyme and flavor-enhancing enzyme added is independently 0.1 to 1% (w / w); and (s2) harvesting the supernatant to obtain an Antarctic krill peptide mixture with umami taste; Wherein, the endonuclease is selected from the group consisting of neutral protease, alkaline protease, papain, composite protease, or a combination thereof; The exonuclease is selected from the group consisting of aminopeptidase, flavor protease, or a combination thereof; The flavor-enhancing enzyme is selected from the group consisting of asparaginase, glutaminase, or a combination thereof.

3. The Antarctic krill peptide mixture according to claim 2, characterized in that The endonuclease includes a composite protease; the exonuclease includes an aminopeptidase; and the flavor-enhancing enzyme includes asparaginase.

4. The Antarctic krill peptide mixture according to claim 2, wherein The material-liquid ratio of the Antarctic krill solution is 1:1-10, preferably 1:3-7, and more preferably 1:4-6.

5. The Antarctic krill peptide mixture according to claim 2, characterized in that In step (s1), the temperature of the enzymatic hydrolysis reaction is 50-70°C, preferably 50-65°C, more preferably 53-60°C, and most preferably 54-58°C.

6. The Antarctic krill peptide mixture according to claim 2, wherein: In step (s1), the Antarctic krill solution is a defatted Antarctic krill solution.

7. A method for preparing the Antarctic krill peptide mixture with umami taste as claimed in claim 1, characterized in that: Including steps: (s1) adding an endo-enzyme, an exo-enzyme and a flavor-enhancing enzyme to an Antarctic krill solution for an enzymatic hydrolysis reaction T1, wherein T1 is 1 to 5 hours, and the amount of the endo-enzyme, exo-enzyme and flavor-enhancing enzyme added is independently 0.1 to 1% (w / w); and (s2) harvesting the supernatant to obtain an Antarctic krill peptide mixture with umami taste; Wherein, the endonuclease is selected from the group consisting of neutral protease, alkaline protease, papain, composite protease, or a combination thereof; The exonuclease is selected from the group consisting of aminopeptidase, Novozymes flavor protease, Angel flavor protease, or a combination thereof; The flavor-enhancing enzyme is selected from the group consisting of asparaginase, glutaminase, or a combination thereof.

8. An Antarctic krill peptide with umami flavor, characterized in that: The Antarctic krill peptide is selected from the following group: (a) a polypeptide having an amino acid sequence shown in any one of SEQ ID NOs: 1 to 5; (b) a polypeptide having ≥80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.5% homology (or identity) to the amino acid sequence of any one of SEQ ID NOs: 1-5, and the polypeptide has the biological function of any one of SEQ ID NOs: 1-13; or (c) A derivative polypeptide formed by substituting, deleting or adding one or more (preferably 1 to 3, more preferably 1 to 2) amino acid residues of the amino acid sequence of any one of SEQ ID NOs: 1 to 5, and retaining the biological function of any one of SEQ ID NOs: 1 to 13.

9. The use of the Antarctic krill peptide mixture according to claim 1 or the Antarctic krill peptide according to claim 8, wherein: Used to prepare umami seasonings.

10. A seasoning, characterized in that Comprising the Antarctic krill peptide mixture according to claim 1 or the Antarctic krill peptide according to claim 8.

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