Milk protein peptide with zinc chelating activity and application of milk protein peptide in preparation of zinc supplement

Abstract

The invention relates to milk protein peptide with zinc chelating activity and application of the milk protein peptide in preparation of a zinc supplement. The sequence of the milk protein peptide is as follows: EMPFPK (Glu-Met-Pro-Phe-Pro-Lys) and / or EAMAPKHKEMPFPK (Glu-Ala-Met-Ala-Pro-Lys-His-Lys-Glu-Met-Pro-Phe-Pro-Ly s), and the sequence of the milk protein peptide is as follows: EMPFPK (Glu-Met-Pro-Phe-Pro-Lys) and / or EAMAPKHKEMPFPK (Glu-Ala-Met- The milk protein peptide not only has relatively strong zinc chelation capacity (the chelation rate reaches 64% or above), but also can improve the zinc transport amount of a cell monomolecular layer of human intestinal adenocarcinoma cells Caco-2, and has relatively strong intestinal zinc absorption promoting activity. In addition, the milk protein peptide disclosed by the invention is derived from milk, and is non-toxic and high in safety.

Description

Technical Field

[0001] The present invention relates to the field of small molecule peptides, and more specifically, to a milk protein peptide with zinc chelating activity and application thereof in the preparation of a zinc supplement. Background Art

[0002] Zinc is the second most abundant trace element in the human body and one of the most basic nutrients required for human health. Zinc affects human health and nutrition by participating in a variety of biological processes. For example, zinc deficiency can lead to growth retardation and impaired immune function. The role of zinc in the human body depends on its bioavailability in tissues, which is affected by the efficiency of intestinal absorption of zinc from food. However, zinc ions easily combine with dietary fiber and phytic acid to form insoluble complexes. This combination interferes with the intestinal absorption process of zinc, thereby reducing zinc bioavailability. Therefore, it is necessary to improve zinc absorption and bioavailability.

[0003] Although multi-mineral supplements can be used as a means of zinc supplementation, they have poor stability in the intestine and have the potential to cause intestinal diseases, which limits their widespread use. Another way to improve zinc absorption is to use commercial phytase or degrade phytic acid in food through fermentation, grinding, etc. However, in actual food processing, it is difficult to perform such treatment on all foods containing phytic acid, which limits the widespread application and development of this method. In addition, food formulations using zinc salts such as zinc sulfate as raw materials have the potential to improve zinc absorption, but this practice may change the original sensory and physicochemical properties of the food, thereby affecting consumer acceptance.

[0004] Food protein-derived peptides are dietary ingredients with multiple biological activities. Among them, some metal chelate peptides can serve as transport carriers for metal ions such as zinc ions during intestinal absorption to improve the bioavailability of dietary zinc and reduce the risk of zinc deficiency. 2+ Combined to form a complex, the complex has high solubility, good stability and high safety in the intestinal environment. For example, Meng et al. (DOI: 10.1016 / j.foodchem.2021.129043) prepared and characterized zinc chelating peptides from tilapia skin collagen, but there are still few studies on zinc chelating peptides.

[0005] Therefore, it is of great significance to develop more peptides with zinc chelating activity. Summary of the invention

[0006] The primary purpose of the present invention is to overcome the problem that zinc chelating peptides are still relatively scarce, and to provide a milk protein peptide with zinc chelating activity. The milk protein peptide not only has a strong zinc chelating ability (chelating rate reaches more than 64%), but also can increase the transport amount of zinc by human intestinal adenocarcinoma cell Caco-2 cell monolayer, and has a strong intestinal zinc absorption promoting activity. In addition, the milk protein peptide is derived from milk, is non-toxic, and has high safety.

[0007] A further object of the present invention is to provide the use of the above-mentioned milk protein peptide in the preparation of a product capable of promoting zinc absorption.

[0008] Another object of the present invention is to provide the use of the above-mentioned milk protein peptide in preparing an adjuvant for zinc supplements.

[0009] Another object of the present invention is to provide the use of the composition of the milk protein peptide and zinc agent in the preparation of zinc supplements.

[0010] Another object of the present invention is to provide a composition comprising the above-mentioned milk protein peptide.

[0011] The above-mentioned object of the present invention is achieved by the following technical solutions:

[0012] A milk protein peptide with zinc chelating activity, wherein the milk protein peptide is the sequence shown in SEQ ID NO:1 and / or the sequence shown in SEQ ID NO:2.

[0013] The milk protein peptide of the present invention is extracted from casein in cow's milk, and the amino acid sequence of the milk protein peptide is as follows: EMPFPK (Glu-Met-Pro-Phe-Pro-Lys) and / or EAMAPKHKEMPFPK (Glu-Ala-Met-Ala-Pro-Lys-His-Lys-Glu-Met-Pro-Phe-Pro-Lys).

[0014] The inventors of the present invention have found that the milk protein peptide of the present invention can react with Zn 2+ EMPFPK binds specifically to Zn via the amide bond in phenylalanine and the carbonyl group in proline. 2+ Binding, while the zinc binding site of EAMAPKHKEMPFPK is the amide bond in lysine.

[0015] The milk protein peptide of the present invention not only has a strong zinc chelating ability (chelating rate reaches more than 64%), but also can enhance the zinc transport capacity of human intestinal adenocarcinoma cell Caco-2 cell monolayer, and has a strong intestinal zinc absorption promoting activity.

[0016] In addition, the milk protein peptide of the present invention is derived from milk, is non-toxic and highly safe.

[0017] The milk protein peptide of the present invention can be obtained by enzymatic hydrolysis, separation and other operations on bovine milk casein, or by solid phase synthesis. Among them, since it can be obtained by solid phase synthesis, it can be mass-produced, and the synthesized milk protein peptide has high purity, stable product quality and market competitiveness.

[0018] Preferably, the milk protein peptide is the sequence shown in SEQ ID NO:2.

[0019] The present invention also protects the use of the milk protein peptide in preparing a product capable of promoting zinc absorption.

[0020] The present invention also protects the use of the milk protein peptide in preparing an auxiliary agent for zinc supplements.

[0021] The use of the above-mentioned combination of milk protein peptide and zinc agent in the preparation of zinc supplements is also within the protection scope of the present invention.

[0022] Preferably, the zinc agent is a zinc salt.

[0023] More preferably, the zinc salt is one or both of an inorganic zinc salt and an organic zinc salt.

[0024] Further preferably, the inorganic zinc salt is at least one of zinc sulfate, zinc chloride or zinc nitrate.

[0025] Further preferably, the organic zinc salt is at least one of zinc gluconate, glycyrrhizin, zinc acetate, zinc citrate, amino acid zinc or zinc lactate.

[0026] A composition comprising the above-mentioned milk protein peptide.

[0027] Preferably, the content of milk protein peptide in the composition is 25-1000 μg / mL.

[0028] Preferably, the composition further comprises a zinc agent.

[0029] More preferably, the zinc agent is a zinc salt.

[0030] Further preferably, the zinc salt is one or both of an inorganic zinc salt and an organic zinc salt.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The present invention provides a milk protein peptide with zinc chelating activity. The milk protein peptide not only has a strong zinc chelating ability (chelating rate reaches more than 64%), but also can increase the transport amount of zinc by human intestinal adenocarcinoma cell Caco-2 cell monolayer, and has a strong intestinal zinc absorption promoting activity. In addition, the milk protein peptide of the present invention is derived from milk, is non-toxic, and has high safety.

[0033] The milk protein peptide of the present invention can be obtained by enzymatic hydrolysis, separation and other operations on bovine milk casein, or by solid phase synthesis. Among them, since it can be obtained by solid phase synthesis, it can be mass-produced, and the synthesized milk protein peptide has high purity, stable product quality and market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Milk protein peptide and Zn 2+ Theoretical binding mode diagram, where Figure A is EMPFPK-Zn 2+ Complex and action site diagram; Figure B is EAMAPKHKEMPFPK-Zn 2+ Diagram of the complex and site of action.

[0035] Figure 2 This is a graph showing the zinc chelation rate of the milk protein peptide of the present invention.

[0036] Figure 3 This is a graph showing the results of the cytotoxicity assay of the milk protein peptide of the present invention.

[0037] Figure 4 This is a graph showing the results of the zinc transport activity of the milk protein peptide of the present invention. DETAILED DESCRIPTION

[0038] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0039] Example 1 Enzymatic hydrolysis, separation, peptide identification and molecular docking of bovine milk casein

[0040] 1.1 Enzymatic hydrolysis and separation of casein

[0041] The bovine milk casein was dissolved in deionized water to obtain a casein solution, wherein the mass concentration of the bovine milk casein in the casein solution was 7%, and then the pH thereof was adjusted to 8.5, and trypsin was added at a mass ratio of 0.6:100 between the enzyme and the substrate for enzymatic hydrolysis at a temperature of 50°C for 3 hours. The solution was then heated to 90°C and kept warm for 10 minutes to inactivate the enzyme, and after cooling to room temperature, the pH was adjusted to 4.6 to precipitate the unenzymatically hydrolyzed casein, and the solution was centrifuged (4000 r / min, 20 minutes), and the supernatant was freeze-dried to obtain a casein hydrolyzate.

[0042] Immobilized metal ion affinity chromatography (IMAC) was used to separate casein hydrolysates. Sepharose 6B was added to NaOH solution (1 mol / L) and epichlorohydrin, activated at 40°C for 3.5 h, filtered, and washed with deionized water 7 times. 6 g of dicarboxymethylamine was added to 40 mL of Na2CO3 (2 mol / L) solution, and the pH was adjusted to 13.0 with 6 mol / L NaOH to obtain a dicarboxymethylamine solution. The activated sepharose 6B was mixed with the dicarboxymethylamine solution in a volume ratio of 1:2, and stirred at 60°C at a speed of 120 r / min for 8 h to obtain a dicarboxymethylamine-sepharose 6B solution. IMAC-Zn 2+ The rubber tube at the bottom of the column (200mm×10mm) was clamped, and the dicarboxymethylamine-agarose gel 6B solution was loaded. The column was precipitated until obvious stratification, and the clamp was released to allow the water layer to flow out of the column. Then, the column was washed with 5 times the volume of the medium with deionized water using a constant flow pump, followed by rinsing with 5 times the volume of the medium with 0.2mol / L ZnSO4 solution, and then with 5 times the volume of the medium with deionized water. Then, 2mL of 15mg / mL casein hydrolysate solution (solvent is water) was loaded onto the column, and first eluted with deionized water at pH 5.5 at a rate of 1mL / min. The absorbance of the eluted component at a wavelength of 214nm was monitored until the unbound peptide component was completely eluted by the deionized water at pH 5.5. The unbound peptide component was named F1. Subsequently, the bound peptide component was eluted with deionized water at pH 2.0 at a rate of 1mL / min. The eluted components were collected, concentrated, and freeze-dried, and the bound peptide component was named F-IMAC. Deionized water with different pH values ​​was used as the mobile phase during the elution process because the zinc chelating peptide can bind to IMAC-Zn under neutral conditions. 2+ The zinc chelating peptide can be eluted under acidic conditions. 2+ The column-bound peptides with zinc chelating activity were mainly present in F-IMAC, so F-IMAC was used for subsequent peptide identification.

[0043] 1.2 HPLC-MS / MS identification of peptide composition of F-IMAC

[0044] The lyophilized F-IMAC was dissolved in a buffer solution (0.1% formic acid (FA), 2% acetonitrile (ACN)). TM-X 33μm Polymeric Reversed Phase, 10mg / 1mL) for desalting, eluted the sample into a new centrifuge tube with elution buffer (0.1% FA, 60% ACN), centrifuged, dried, and then redissolved in Nano-LC mobile phase A, which was 0.1% formic acid solution. 2μL of the sample was loaded onto a nanoViper C18 pre-column (3μm), washed and desalted, and then separated on an Acclaim PepMap C18 analytical column (75μm x 25cm). The F-IMAC peptide was identified using an Orbitrap FusionLumos mass spectrometer connected to an EASY-nanoLC 1200 liquid chromatograph. Spray voltage: 1.9 kV; ion transfer tube heating temperature: 275 ° C; liquid chromatography elution gradient: mobile phase B (80% ACN, 0.1% FA) increased from 5% to 38% within 60 min; mass spectrometry parameters were set as follows: mass spectrometry scanning mode: information-dependent acquisition working mode (DDA, Data Dependent Analysis); primary mass spectrometry scanning resolution was 70000, scanning range was 100-1500 m / z, and maximum injection time was 100 ms; secondary mass spectrometry ion maximum injection time was 50 ms; collision chamber energy (high energy collision induced dissociation, HCD): 28 eV, applicable to all precursor ions; dynamic exclusion setting: 6s.

[0045] PEAKS Studio 8.5 software was used to process and search the original raw format spectrum files obtained by mass spectrometry. The database used for analysis was from the Bos taurus (Bovine) casein protein database. The search parameters were set as follows: the mass tolerance of the primary mass spectrometry was 10 ppm and the secondary mass spectrometry was 0.05 Da.

[0046] 1.3 Molecular docking

[0047] Molecular docking technology was used to simulate the interaction between casein peptides and zinc ions, and docking energy was used as the evaluation criterion to screen out casein zinc chelating peptides that bind stably to zinc ions. The specific steps are as follows: First, create a new zinc ion model using DiscoveryStudio Client 2019 software. Secondly, import the peptide sequence into the software and use the protein preparation tool to hydrogenate and minimize its energy. The zinc ion is set as the ligand, the peptide molecule is set as the receptor, and the entire peptide molecule is defined as the docking site. Finally, select the calculation docking binding energy in the docking module to predict the binding energy of its action.

[0048] The selected high-activity zinc chelating peptides were docked with Zn using the CDOCKER module in the Discovery Studio Client 2019 docking simulation. 2+ The docking of the zinc chelation protein can be used to determine the amino acid site of action, the type of binding force, the bond length and other information, thereby realizing the prediction of the zinc chelation mechanism.

[0049] 50 different F-IMAC peptides were identified in the F-IMAC component by HPLC-MS / MS. By comparing the secondary mass spectra of each peptide with the information in the database, it was found that these peptides were mainly distributed in four subtypes of casein: αs2-casein had 20 peptides, αs1-casein had 15 peptides, β-casein had 9 peptides, and κ-casein contained 6 peptides. The length of these peptides ranged from 6 to 23 amino acids, and the molecular weight was less than 3kDa.

[0050] The 50 peptides were ranked according to the binding energy of molecular docking. The lower the binding energy, the better the peptides are at binding to Zn. 2+ The more stable the binding. A total of three highly active zinc chelating peptides were screened, two of which were EMPFPK and EAMAPKHKEMPFPK. Both of these milk protein peptides are derived from β-casein in bovine casein. The sequence information and molecular docking results of casein zinc chelating peptides identified by NanoLC-MS / MS are shown in Table 1.

[0051] Table 1 Sequence information and molecular docking results of casein zinc chelating peptides identified by NanoLC-MS / MS

[0052]

[0053] Milk protein peptides and Zn 2+ Theoretical combination model such as Figure 1 As shown, Figure A is EMPFPK-Zn 2+ Complex and action site diagram; Figure B is EAMAPKHKEMPFPK-Zn 2+ Complex and action site diagram. 2+ In the complex, Zn 2 + Through the Metal-Acceptor action, it not only combines with the amide bond of phenylalanine (Phe4) to form a Zn-O bond with a bond length of It also binds to the carbonyl oxygen atom in proline (Pro5) to form a Zn-O bond with a bond length of In EAMAPKHKEMPFPK-Zn 2+ In the complex, Zn 2+It combines with the amide bond of lysine (Lys8) through the Metal-Acceptor to form a Zn-O bond with a bond length of The longer the bond length, the more stable the structure. Therefore, in EMPFPK, Zn 2+ The binding to phenylalanine may be more stable than to proline.

[0054] Example 2 Zinc chelating activity and cytotoxicity

[0055] 2.1 Zinc chelating activity verification

[0056] The milk protein peptides EMPFPK and EAMAPKHKEMPFPK obtained by the above screening were synthesized by Nanjing Jiepeptide Biotechnology Co., Ltd. using solid phase synthesis method, with a purity greater than 98%, and then the zinc ion chelating activity was determined.

[0057] The method for determining the zinc ion chelation rate is as follows: dissolve 1 mg / mL of the sample in HEPES-KOH buffer (40 mM), take 175 μL of the sample solution and add it to a 96-well plate, and preheat it at 37°C for 10 minutes. Add 25 μL of ZnSO4 solution (250 μmol / L) to each well, shake and mix, react at 37°C for 30 minutes, and then add 100 μL of PAR solution (2 mmol / L) to terminate the reaction. After 10 minutes, measure the absorbance at 500 nm. EDTA was selected as the positive control, HEPES-KOH buffer was selected as the blank group, and three parallel samples were set for each sample. The formula for calculating the zinc ion chelation rate is as follows:

[0058] Zinc ion chelation rate (%) = (Abs 空白 -Abs 样品 ) / Abs 空白 ×100%, where Abs 空白 is the absorbance value of the blank sample, Abs 样品 is the absorbance value of the sample.

[0059] 2.2 MTT assay for cytotoxicity

[0060] Caco-2 cells are human intestinal adenocarcinoma cells with biochemical and morphological characteristics similar to intestinal epithelial cells. They have been shown to be a powerful tool for studying the absorption of zinc and other minerals. Caco-2 cells (American Type Culture Collection, Rockville, MD, USA) were seeded into T25 culture flasks. When the cell density reached 70% to 80%, 0.25% EDTA-trypsin was added and digested at 37°C for 3 minutes. The cells were passaged at a ratio of 1:3. Cells of passage 15 to 30 were selected for subsequent experiments. The complete culture medium was prepared with 79% EMEM basal medium, 20% fetal bovine serum and 1% antibiotics (penicillin and streptomycin). The culture environment of the cells was 37°C, 5% CO2, and 95% relative humidity. The complete culture medium was replaced every 2 days.

[0061] The MTT assay was used to determine whether milk protein peptides were toxic to the growth of Caco-2 cells. Caco-2 cells in the logarithmic growth phase were digested with 0.25% EDTA-trypsin and inoculated into 96-well plates (density 5×10 4 / well), and incubate in complete medium for 24 hours to allow the cells to fully adhere. Then remove the complete medium, add 100 μL of milk protein peptide sample solutions (dissolved in complete medium) of different concentrations (25, 50, 100, 250, 500, 1000 μg / mL), use the complete medium as the blank control group, and put it in the incubator for 24 hours. Remove the sample solution, add 100 μL of MTT solution (0.5 mg / mL) and treat for 4 hours, and finally remove the MTT solution. Next, add 100 μL of DMSO to dissolve the purple crystalline product, and measure the absorbance at 490 nm. The cell viability calculation formula is as follows: Cell viability (%) = (absorbance of sample group / absorbance of blank control group) × 100%.

[0062] The test results of zinc chelation activity are as follows Figure 2 As shown (values ​​are expressed as mean ± standard deviation, n = 3; there are significant differences (p < 0.05) between the mean values ​​in each column with different labels (a to c). Figure 2 It can be seen that the zinc ion chelation rate of EMPFPK is 64.29±0.27%, and the zinc ion chelation rate of EAMAPKHKEMPFPK is 69.74±0.05%, which are higher than the iron chelation rates of some existing iron chelating peptides, such as rapeseed-derived zinc chelating peptides Ala-Arg (34.7%) and Gly-Lys-Arg (54.5%) (see document DOI: 10.1016 / j.foodchem.2014.10.030). This shows that the milk protein peptide of the present invention has good zinc chelating activity.

[0063] Cytotoxicity test results Figure 3 As shown, the results of the cytotoxicity test showed that EMPFPK and EAMAPKHKEMPFPK had no toxic effects on Caco-2 cells within the concentration range of 25 to 1000 μg / mL, and subsequent zinc transport activity experiments were performed within this concentration range.

[0064] Example 3 Determination of zinc transport activity

[0065] Before cell inoculation, 0.5 mL of complete medium was added to the upper chamber of a 12-well polyester Transwell membrane culture plate (PET, Corning, 3460), and 1.5 mL of complete medium was added to the lower chamber. The plate was placed in an incubator for 1 hour to allow it to equilibrate. After 1 hour, the complete medium in the upper chamber was removed. When the cell coverage rate reached 80% of the T25 culture flask, 4 × 10 5 The cells were inoculated into the upper chamber of a 12-well polyester Transwell membrane culture plate at a density of 100 cells / mL. The cells were cultured every other day for 21 days. The integrity of the cell monolayer was evaluated by measuring the transmembrane electrical resistance (TEER). When the TEER value was greater than 500Ω / cm 2 This indicates that the Caco-2 cell monolayer model was successfully established and can be used for zinc transport activity determination experiments.

[0066] The milk protein peptide sample was mixed with the ZnSO4 solution and reacted at 37°C for 1 hour to obtain a peptide-zinc mixture. Before the transport experiment began, a new 12-well culture plate was prepared and 1.5 mL of complete culture medium was added. The Caco-2 monolayer cell membrane cultured for 21 days was transferred to the new 12-well plate. The pre-mixed peptide-zinc solution (sample group) and ZnSO4 solution (control group) were added to the upper chamber of the transport model. The Zn in the sample group and the control group was 2+ The concentration was 50 μg / mL. After the transport started, 1 mL of culture medium was taken from the lower chamber of the Transwell nested plate at 30, 60, 120, and 180 min, and 1 mL of culture medium was quickly added to maintain the volume of the transport system unchanged. The zinc concentration of the lower chamber culture medium at each time point was determined by flame atomic absorption spectrometry. The formula for calculating the zinc transport amount at each time point is as follows:

[0067]

[0068] In the formula, T n represents the total zinc transport amount at each time point (μg); 1.5 represents the volume of the lower complete culture medium (mL); C nrepresents the zinc concentration (μg / mL) in the samples obtained at different time points; 0.40 represents the zinc concentration in the complete culture medium itself (μg / mL); 1 represents the volume of the sample obtained from the lower layer (mL); n represents the independent variable, which can be 1, 2, 3, 4, representing 4 different time points, namely 30min, 60min, 120min, and 180min.

[0069] Zinc transport activity test results Figure 4 As shown (values ​​are expressed as mean ± standard deviation, n = 3. The mean values ​​of different letters (a-i) in each column are significantly different (p < 0.05)). Within 180 min, the control group (only Zn was added) 2+ ) and sample groups (EMPFPK and EAMAPKHKEMPFPK) gradually increased their zinc transport. When transported to 30min, the zinc transport of the sample group was significantly higher than that of the control group. Among them, EMPFPK increased by 300.41% compared with the control group, and EAMAPKHKEMPFPK increased by 882.81% compared with the control group, which showed that EMPFPK and EAMAPKHKEMPFPK quickly exerted the activity of promoting zinc transport after the start of transport, and increased the absorption of zinc by Caco-2 cell monolayer. During the transport process, the zinc transport of EAMAPKHKEMPFPK was always significantly (p < 0.05) higher than that of EMPFPK. When transported to 60min, the zinc transport of EMPFPK and EAMAPKHKEMPFPK increased by 185.23% and 318.49% respectively compared with the control group. When transported to 120min, the zinc transport of EMPFPK and EAMAPKHKEMPFPK increased by 71.74% and 145.45% respectively compared with the control group. When transported to 180 minutes, the zinc transport amounts of EMPFPK and EAMAPKHKEMPFPK were increased by 67.40% and 123.37% respectively compared with the control group. The above indicates that the milk protein peptide of the present invention has an excellent effect in improving the intestinal zinc absorption activity.

[0070] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A milk protein peptide having zinc chelating activity, characterized in that: The milk protein peptide is the sequence shown in SEQ ID NO: 1 and / or the sequence shown in SEQ ID NO:

2.

2. The milk protein peptide according to claim 1, characterized in that The milk protein peptide is the sequence shown in SEQ ID NO:

2.

3. Use of the milk protein peptide according to any one of claims 1 to 2 in the preparation of a product capable of promoting zinc absorption.

4. Use of the milk protein peptide according to any one of claims 1 to 2 in the preparation of a zinc supplement.

5. Use of the milk protein peptide according to any one of claims 1 to 2 in preparing an adjuvant for zinc supplements.

6. Use of the composition of the milk protein peptide and zinc agent according to any one of claims 1 to 2 in the preparation of a zinc supplement.

7. The use according to claim 6, characterized in that The zinc agent is a zinc salt.

8. A composition, characterized in that It comprises the milk protein peptide described in any one of claims 1 to 2.

9. The composition according to claim 8, characterized in that The content of milk protein peptide in the composition is 25-1000 μg / mL.

10. The composition according to claim 8 or 9, characterized in that A zinc agent is also included in the composition.

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