Zinc-chelated salmon fishbone phosphopeptides, preparation method thereof and zinc-supplementing minced fillet

Abstract

The preparation method of the zinc-chelated salmon fishbone phosphopeptide comprises the following steps: adding water into salmon fishbone powder, homogenizing, centrifuging and drying to obtain salmon fishbone crude protein, hydrolyzing by using a compound enzyme, and filtering to obtain the zinc-chelated salmon fishbone phosphopeptide. Performing enzyme deactivation and centrifugation to obtain a salmon fish bone peptide solution, and performing dialysis and freeze drying to obtain salmon fish bone peptide freeze-dried powder; the preparation method comprises the following steps: compounding salmon fishbone peptide freeze-dried powder and sodium tripolyphosphate to prepare salmon fishbone phosphopeptide freeze-dried powder, dissolving the salmon fishbone phosphopeptide freeze-dried powder in water, carrying out chelation reaction on the salmon fishbone phosphopeptide freeze-dried powder and a zinc source to obtain a compound solution, and carrying out ethanol precipitation, centrifugal separation and drying treatment to obtain the zinc-chelated salmon fishbone phosphopeptide. The zinc-chelated salmon fishbone phosphopeptide prepared by the chelating reaction of the salmon fishbone compound enzyme phosphopeptide and zinc ions is high in antioxidant activity and strong in zinc binding capacity, the absorptivity and bioavailability of the zinc element are effectively improved, and the taste of the product is optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of salmon bone phosphopeptides, and in particular to a zinc-chelated salmon bone phosphopeptide, a preparation method thereof, and zinc-supplemented fish paste. Background Art

[0002] Zinc, an essential micronutrient for the human body, plays a key role in maintaining normal physiological functions. As a key cofactor for over 300 enzymes, zinc is involved in physiological processes such as nucleic acid metabolism, protein synthesis, immune function maintenance, and wound healing.

[0003] Traditional zinc supplements mainly include inorganic or organic zinc salts such as zinc sulfate, zinc gluconate, and zinc citrate. Although these compounds have high zinc content, they generally have problems such as low bioavailability (approximately 30-50%) and strong gastrointestinal irritation. In recent years, zinc-binding bioactive peptides have become a research hotspot due to their unique advantages. These peptide-zinc chelates can significantly improve the solubility and intestinal absorption rate of zinc by mimicking the structure of natural zinc carrier proteins. However, the actual preparation of peptide-zinc chelates has low chelation rates, high raw material costs, and limited sources of active peptides.

[0004] The fish bones produced during salmon processing account for about 30%-40% of the total weight of the fish. Traditional treatment methods are mostly discarding or low-value processing (such as fish meal), resulting in waste of resources such as protein and minerals, while increasing the environmental burden. How to make high-value use of salmon bones is an issue that needs to be solved. Summary of the Invention

[0005] The present invention provides a zinc-chelated salmon bone phosphopeptide, a preparation method thereof and zinc-supplemented fish paste, in order to solve the above problems.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] A method for preparing zinc-chelated salmon bone phosphopeptide comprises the following steps:

[0008] The salmon bone powder is homogenized with water and centrifuged to obtain a salmon bone crude protein filtrate, which is then dried to obtain salmon bone crude protein. The salmon bone crude protein is enzymatically hydrolyzed using a complex enzyme. After the enzymatic hydrolysis is completed, the enzyme is inactivated and centrifuged to obtain a salmon bone peptide solution, which is then dialyzed and freeze-dried to obtain salmon bone peptide freeze-dried powder;

[0009] The salmon bone peptide freeze-dried powder is compounded with sodium tripolyphosphate to prepare the salmon bone phosphopeptide freeze-dried powder, the salmon bone phosphopeptide freeze-dried powder is dissolved in water and then subjected to a chelation reaction with a zinc source to obtain a complex solution, which is subjected to ethanol precipitation, centrifugal separation and freeze-drying treatment to finally obtain the zinc-chelated salmon bone phosphopeptide.

[0010] Furthermore, the feeding mass molar ratio of the salmon bone peptide to sodium tripolyphosphate is 20kg:0.1mol.

[0011] Furthermore, the mass ratio of the salmon bone phosphopeptide freeze-dried powder to the zinc element in the zinc source is 1:0.5-2;

[0012] The zinc source is zinc sulfate heptahydrate.

[0013] Furthermore, the complex enzyme includes pepsin and trypsin;

[0014] The specific enzymatic hydrolysis method is: first add pepsin for 2 hours, pH 2.0; then add trypsin for 2 hours, pH 8.0; the addition amount of pepsin and trypsin is 5000 U / g, and the enzymatic hydrolysis temperature is 50°C.

[0015] Furthermore, the preparation method of the salmon bone phosphopeptide freeze-dried powder is: dissolving the salmon bone peptide freeze-dried powder in a sodium tripolyphosphate solution to form a mixed system, adjusting the pH to 5.0 and then freeze-drying to obtain a freeze-dried intermediate product; incubating the obtained freeze-dried intermediate product under specific temperature and humidity conditions, and after the incubation is completed, redissolving, dialyzing and freeze-drying again to obtain the salmon bone phosphopeptide freeze-dried powder.

[0016] Furthermore, the incubation parameters are: relative humidity of 70-85%, temperature of 40-55° C., and incubation time of 10-15 hours.

[0017] Furthermore, the chelating reaction conditions are: adjusting the pH of the reaction system to within the range of 7.0-9.0, and conducting the reaction using magnetic stirring.

[0018] Furthermore, the ethanol precipitation step uses anhydrous ethanol, and the volume ratio of anhydrous ethanol to the volume of the complex solution is 3:1;

[0019] The molecular weight cut-off of the dialysis bag used for dialysis was 3500 Da.

[0020] Another aspect of the present invention provides a zinc-chelated salmon bone phosphopeptide, which is characterized in that it is prepared by the preparation method of the zinc-chelated salmon bone phosphopeptide described in claim 1.

[0021] In another aspect, the present invention provides a zinc-supplemented fish paste, which contains the zinc-chelated salmon bone phosphopeptide, wherein the mass fraction of the zinc-chelated salmon bone phosphopeptide added is 0.15%.

[0022] The beneficial effects of the present invention are:

[0023] The application discloses a preparation method of zinc-chelated salmon fish bone phosphopeptide, and the zinc-chelated salmon fish bone phosphopeptide is prepared through a chelation reaction between salmon fish bone complex enzyme phosphopeptide and zinc ions, has high antioxidant activity, strong zinc binding capacity, effectively improves the absorption rate and bioavailability of zinc elements, optimizes the taste and convenience of the product, has the use as a food additive or a nutritional supplement, and can be widely applied to the fields of food, beverage, cosmetics, biological medicine, health care and the like. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without any creative effort.

[0025] Figure 1 The figure is the zinc binding capacity and antioxidant capacity of the zinc-chelated salmon fish bone peptide prepared by three groups of enzyme hydrolysis in the embodiment 1 of the present application.

[0026] Figure 2 The figure is the phosphorylation degree of the zinc-chelated salmon fish bone phosphopeptide prepared in the embodiments 2-4 of the present application.

[0027] Figure 3 The figure is the zinc content of the zinc-chelated salmon fish bone phosphopeptide prepared in the embodiments 2-4 of the present application.

[0028] Figure 4 The figure is the texture of the zinc supplement surimi prepared in the embodiments 5-7 and the comparative examples 1-2 of the present application.

[0029] Figure 5 The figure is the flavor of the zinc supplement surimi prepared in the embodiments 5-7 and the comparative examples 1-2 of the present application. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without any creative effort are within the protection scope of the present application.

[0031] Example

[0032] Example 1: Screening of the best enzyme for preparing salmon bone peptide

[0033] The salmon bone crude protein was enzymatically hydrolyzed using pepsin, trypsin, and a composite protease consisting of pepsin and trypsin, respectively. The specific steps are as follows:

[0034] Step 1: Mix the thawed salmon bone raw material with 4°C deionized water at a material-liquid ratio of 1:5 (w / v), homogenize at 1000 rpm for 10 minutes to obtain a uniform dispersion system, then place the homogenate on a magnetic stirrer and stir continuously for 5 hours to promote protein dissolution, centrifuge at 4000-6000 rpm for 15 minutes, collect the supernatant, pre-freeze at -40°C, and dry at a vacuum degree of ≤50 Pa for 24-48 hours to obtain salmon bone crude protein powder;

[0035] Step 2. Set up three groups of experiments: dissolve three equal portions of the above salmon bone crude protein powder in deionized water at a material-liquid ratio of 1:45 (w / v), adjust the pH of the system to 7.0 and maintain a constant temperature of 50°C. Add the following three groups of enzymes to the system for directional enzymatic hydrolysis. After the enzymatic hydrolysis is completed, heat at 90°C to inactivate the enzyme for 10 minutes, centrifuge at 4000-6000rpm for 15 minutes, and obtain the supernatant. Prepare salmon bone peptide freeze-dried powder using freeze-drying technology (parameters are the same as in step 1), seal and store at -20°C for later use;

[0036] Group 1: Add 10000U / g pepsin, pH 2.0, and enzymatically hydrolyze for 4h;

[0037] Group 2: Add 10000U / g trypsin, pH 8.0, and enzymatically hydrolyze for 4h;

[0038] Group 3 (step-by-step enzymatic hydrolysis): first add 5000 U / g pepsin, pH 2.0, and enzymatic hydrolysis for 2 h; then add 5000 U / g trypsin, pH 8.0, and enzymatic hydrolysis for 2 h;

[0039] Step 3: Dissolve the salmon bone peptide freeze-dried powder in deionized water, add zinc sulfate at a mass ratio of 2:1 between zinc and salmon bone peptide freeze-dried powder, adjust the pH to 8.5, and react at 25-30°C with magnetic stirring (300-500 rpm) for 90 minutes. After the reaction is terminated, add 3 times the volume of anhydrous ethanol to precipitate the chelated product, centrifuge (4000-6000 rpm, 10 min), collect the precipitate, and freeze-dry (parameters are the same as step 1) to finally obtain the zinc-chelated salmon bone peptide product.

[0040] The zinc binding capacity and ABTS free radical scavenging rate of the above three groups of zinc chelated salmon bone peptide products were measured;

[0041] 1. Zinc binding capacity determination:

[0042] Zinc binding capacity was determined using a kit. The sample was prepared into a 1 mg / mL solution, a colorimetric reagent was added, and the solution was incubated at 37°C for 5 minutes. The absorbance at 630 nm was then read. The zinc ion concentration was calculated according to formula (1):

[0043]

[0044] Where: C 标准 24 μmol / L; A 测定 is the absorbance of the sample; A 标准 is the absorbance of the standard.

[0045] 2. ABTS free radical scavenging rate determination method:

[0046] Mix ABTS solution [i.e., 2,2'-azino-bis(3-ethyl-benzothiazole-6-sulfonic acid) diammonium salt solution] with potassium persulfate solution and react in the dark for 12-16 hours to form ABTS+ free radical stock solution. Dilute with phosphate buffer to an absorbance of 0.7±0.02 at 734 nm before use. Next, take 1 mg / mL zinc-chelated salmon bone phosphopeptide and mix it with the diluted ABTS+ free radical solution. After sufficient shaking, react in the dark for 6-10 minutes and measure the absorbance (A) at 734 nm. 样品 ), and at the same time, the absorbance of the blank group (using solvent instead of sample solution) was measured (A 空白 ) and the control group (only ABTS + free radical solution) (A 对照 Finally, according to the formula "Clearance (%) = [1-(A 样品 -A 空白 ) / A 对照 ]×100%" to calculate the free radical scavenging rate and evaluate the ABTS free radical scavenging activity of the samples.

[0047] Results: The results are as follows Figure 1 As shown by Figure 1 It can be seen that the salmon bone peptide product prepared by the step-by-step enzymatic hydrolysis method using a complex enzyme (pepsin + trypsin) has the strongest zinc binding ability and antioxidant capacity.

[0048] Example 2:

[0049] A method for preparing zinc-chelated salmon bone phosphopeptide comprises the following steps:

[0050] Step 1: After thawing the frozen salmon bones, crush them into granules, then add 4°C deionized water at a material-liquid ratio (mass / volume ratio, w / v) of 1:5, and homogenize at 1000rpm for 10 minutes to obtain a uniform suspension. The homogenized mixture is placed on a magnetic stirrer and stirred continuously for 5 hours to fully dissolve the protein. Subsequently, the mixture is centrifuged at 4000-6000rpm and 4°C for 15-20 minutes to ensure full separation of the solid and liquid phases, and then the supernatant is collected and pre-frozen to below -40°C, and then sublimated and dried under vacuum conditions (≤50Pa) for 24-48 hours to ensure the stability and activity of the protein and remove moisture by freeze-drying, and finally salmon bone crude protein is obtained.

[0051] Step 2: Mix salmon bone protein with water at a material-liquid ratio (mass / volume ratio, w / v) of 1:45, stir homogeneously to prepare a protein solution, adjust the pH of the protein solution to 7.0, and maintain the temperature of the reaction system at 50°C. Subsequently, add pepsin to the system and enzymolyze at a pH of 2 for 2 hours, then add trypsin and enzymolyze at a pH of 8 for 2 hours. The amount of pepsin and trypsin added is 5000U / g protein, and a controlled enzymatic hydrolysis reaction is carried out. After the enzymatic hydrolysis is completed, heat at 90°C for 10 minutes to inactivate the protease to completely terminate the enzymatic hydrolysis reaction, and then centrifuge at 4000-6000rpm for 10-15 minutes to obtain the supernatant, i.e., the salmon bone peptide solution. The obtained salmon bone peptide solution is pre-frozen to below -40°C, vacuum sublimation dried for 24-48 hours, to obtain salmon bone peptide freeze-dried powder, which is sealed and stored at -20°C for subsequent use.

[0052] Step 3. Dissolve the salmon bone peptide freeze-dried powder in 0.1 mol / L sodium tripolyphosphate solution at a material-liquid ratio (mass / volume ratio, w / v) of 1:15, and mix thoroughly to obtain a salmon bone-sodium tripolyphosphate mixed solution. After adjusting the pH of the mixed solution to 5.0, pre-freeze at -40°C, vacuum dry for 24-48 hours, and freeze-dry to obtain a freeze-dried intermediate. The freeze-dried intermediate is placed in a constant temperature and humidity environment for incubation reaction, controlling the relative humidity to 75%, the temperature to 50°C, and the reaction time to 12 hours. After the reaction is completed, the product is dissolved in deionized water and placed in a dialysis bag with a molecular weight cutoff of 3500Da to ensure effective removal of small molecule impurities. Dialysis is performed at 4°C for 48 hours, and the external dialysis fluid is replaced every 4 hours. Finally, the dialysate is pre-frozen at -40°C, vacuum dried for 24-48 hours, and freeze-dried to obtain high-purity salmon bone phosphopeptide freeze-dried powder.

[0053] Step 4: Dissolve the prepared salmon bone phosphopeptide lyophilized powder in deionized water to prepare a salmon bone phosphopeptide aqueous solution. Add zinc sulfate to the salmon bone phosphopeptide aqueous solution at a mass ratio of 1:0.5 between the salmon bone phosphopeptide lyophilized powder and the zinc element. After sufficient dissolution, obtain a salmon bone phosphopeptide-zinc sulfate mixed system (complex solution, i.e., peptide zinc chelate solution); adjust the pH of the mixed system to 8.5, and carry out magnetic stirring at a speed of 300-500 rpm for 30 minutes at a constant temperature of 25-30°C; after the reaction is completed, add anhydrous ethanol to the mixed system (peptide zinc chelate solution) for precipitation and purification, wherein the volume ratio of the peptide zinc chelate solution to anhydrous ethanol is 1:3 (v / v). The mixed system was centrifuged at 4000-6000 rpm for 10-15 minutes, and the precipitate was collected. Finally, the precipitate was pre-frozen at -40°C with a vacuum degree of ≤50 Pa, and freeze-dried in a vacuum for 24-48 hours to obtain zinc-chelated salmon bone phosphopeptide.

[0054] Example 3:

[0055] The only difference between this embodiment and Example 2 is that, in this embodiment, the mass ratio of salmon bone phosphopeptide freeze-dried powder to zinc element is 1:1, and the other processing steps and parameters are the same as those in Example 1.

[0056] Example 4:

[0057] The only difference between this embodiment and Example 2 is that, in this embodiment, the mass ratio of salmon bone phosphopeptide freeze-dried powder to zinc element is 1:2, and the other processing steps and parameters are the same as those in Example 1.

[0058] Example 5:

[0059] Step 1: Remove the head, viscera, scales, tail and ribs of a fresh Spanish mackerel, and mince the meat with a meat mincer to obtain surimi: take 100 g of fresh Spanish mackerel surimi, add 0.15% by mass of the zinc-chelated salmon bone phosphopeptide prepared in Example 2, and then wash twice with twice the mass of clean water to obtain a surimi product;

[0060] Step 2: Place the surimi product in a Petri dish with a diameter of about 10 cm, and use a two-stage heating method: 40°C water bath for 30 minutes, 100°C water bath for 10 minutes, and place the heated surimi gel in ice water to cool for 10 minutes;

[0061] Step 3: Cover with plastic wrap and place in a 4°C cold storage to cool and set, thereby preparing zinc-supplemented fish paste; package the set zinc-supplemented fish paste in a safe packaging bag, and seal it with a heat sealer for storage.

[0062] Example 6:

[0063] The difference between this embodiment and Example 5 is only that, in this embodiment, the zinc-chelated salmon fish bone phosphopeptide prepared in Example 3 is added, and other processing steps and parameters are the same as those in Example 5. Finally, zinc-supplemented surimi is prepared.

[0064] Example 7:

[0065] The difference between this embodiment and Example 5 is only that, in this embodiment, the zinc-chelated salmon fish bone phosphopeptide prepared in Example 4 is added, and other processing steps and parameters are the same as those in Example 5. Finally, zinc-supplemented surimi is prepared.

[0066] Comparative Example

[0067] Comparative Example 1:

[0068] The difference between this comparative example and Example 5 is only that, in this embodiment, the zinc-chelated salmon fish bone peptide prepared in Example 1 by stepwise complex enzyme hydrolysis (without phosphatization treatment) is added, and other processing steps and parameters are the same as those in Example 5. Finally, zinc-supplemented surimi is prepared.

[0069] Comparative Example 2:

[0070] The difference between this comparative example and Example 5 is only that, in this comparative example, no zinc-chelated salmon fish bone phosphopeptide is added, and other processing steps and parameters are the same as those in Example 5, i.e., a blank control, to prepare ordinary surimi.

[0071] Product determination:

[0072] 1. Determination of the degree of phosphorylation and zinc binding capacity of the zinc-chelated salmon fish bone phosphopeptide prepared in Examples 2-4

[0073] (1) Determination of the degree of phosphorylation:

[0074] The phosphorylation determination kit (E-BC-K245-M, Elabscience Biotechnology Co., Ltd., Wuhan, China) was used for determination.

[0075] The degree of phosphorylation of the zinc-chelated salmon fish bone phosphopeptide and its phosphorylated product is shown in Table 1. Figure 2 The products prepared by chelation reaction at different ratios have some differences in the degree of phosphorylation, and the degree of phosphorylation of Example 4 is the smallest.

[0076] (2) Determination of zinc binding capacity:

[0077] The zinc binding capacity was determined using a kit. The samples prepared in Examples 2-4 were prepared into a solution with a mass concentration of 1 mg / mL. A colorimetric reagent was added and incubated at 37°C for 5 minutes. The absorbance at 630 nm was read. The zinc-chelated salmon bone peptide prepared by enzymatic hydrolysis of the complex enzyme in Example 1 was used as a control group. The zinc ion concentration was calculated according to formula (1):

[0078]

[0079] Where: C 标准 24 μmol / L; A 测定 is the absorbance of the sample; A 标准 is the absorbance of the standard.

[0080] The results of zinc binding capacity of different groups are as follows Figure 3 As shown, the zinc-chelated salmon bone phosphopeptide prepared in Example 4 with a peptide to zinc mass ratio of 1:2 had the strongest zinc binding ability. The results showed that the zinc chelating ability of the phosphopeptide was significantly affected, and the zinc chelating ability was inversely proportional to the degree of phosphorylation.

[0081] 2. Exploring the texture and flavor characteristics of the surimi products prepared in Examples 5-7 and Comparative Examples 1-2

[0082] (1) Texture characteristics analysis

[0083] A TA.XT.pius texture analyzer was used for full texture analysis and surimi gel strength measurement. Surimi samples were formed into cubes with sides of 40 mm. A P-5S probe, suitable for measuring surimi gel strength, was used. The speed was set to 2 mm / s before and after the test, and the trigger force was set to 20 g. The full texture analysis diagram displays the mechanical response of the surimi during compression and shear, including indicators such as hardness, elasticity, and cohesion. These indicators can be analyzed to assess the taste and texture of the surimi.

[0084] The results are as follows Figure 4 As shown in Example 7, the surimi gel strength increased under the conditions, forming a stable gel structure. Myosin exhibits strong hydrophilicity during dissolution, allowing this network structure to accommodate a large amount of free water. When the surimi is heated and converted into a gel, this structure becomes even more uniform and dense, imparting excellent elasticity, hardness, and water-holding properties to the product. These properties ensure that surimi products meet extremely high standards in taste and texture.

[0085] (2) Flavor characteristics analysis

[0086] The flavor characteristics of the samples were analyzed using the SA402B electronic tongue device. The sample to be tested was weighed (2.0±0.01) g and added to 25 mL of deionized water. The sample was homogenized for 1 min and then ultrasonicated for 5 min. After standing for 30 min, it was centrifuged at 12000 r / min and 4°C for 15 min. The upper oil layer was removed and filtered. The lower precipitate was removed and the above steps were repeated. The two filtrates were combined and the volume was adjusted to 100 mL. 5 mL of the fixed volume solution and 75 mL of deionized water were taken into the special sampling cup for the electronic tongue and measured at room temperature.

[0087] The results are as follows Figure 5 As shown, analysis of the five basic flavors of surimi revealed no significant changes in sourness and sweetness compared to the blank control. Bitterness increased somewhat in the Example group, likely due to the peptide's inherent properties. However, given the relatively low dosage, the bitterness was not significantly higher than that of Comparative Example 1. Regarding umami, the surimi treated with the method of Example 7 achieved the highest umami value, enhancing the flavor of the surimi gel.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing zinc-chelated salmon bone phosphopeptide, characterized in that: The steps include: The salmon bone powder is homogenized with water and centrifuged to obtain a salmon bone crude protein filtrate, which is then dried to obtain salmon bone crude protein. The salmon bone crude protein is enzymatically hydrolyzed using a complex enzyme. After the enzymatic hydrolysis is completed, the enzyme is inactivated and centrifuged to obtain a salmon bone peptide solution, which is then dialyzed and freeze-dried to obtain salmon bone peptide freeze-dried powder; The salmon bone peptide freeze-dried powder is compounded with sodium tripolyphosphate to prepare the salmon bone phosphopeptide freeze-dried powder, the salmon bone phosphopeptide freeze-dried powder is dissolved in water and then subjected to a chelation reaction with a zinc source to obtain a complex solution, which is subjected to ethanol precipitation, centrifugal separation and freeze-drying treatment to finally obtain the zinc-chelated salmon bone phosphopeptide.

2. The preparation method and application of a zinc-chelated salmon bone phosphopeptide according to claim 1, characterized in that: The feeding mass molar ratio of the salmon bone peptide to sodium tripolyphosphate is 20kg:0.1mol.

3. The preparation method and application of a zinc-chelated salmon bone phosphopeptide according to claim 1, characterized in that: The mass ratio of the salmon bone phosphopeptide freeze-dried powder to the zinc element in the zinc source is 1:0.5-2; The zinc source is zinc sulfate heptahydrate.

4. The preparation method and application of a zinc-chelated salmon bone phosphopeptide according to claim 1, characterized in that: The complex enzyme includes pepsin and trypsin; The specific enzymatic hydrolysis method is: first add pepsin for 2 hours, pH 2.0; then add trypsin for 2 hours, pH 8.0; the added amount of pepsin and trypsin is 5000 U / g, and the enzymatic hydrolysis temperature is 50°C.

5. The method for preparing zinc-chelated salmon bone phosphopeptide according to claim 1, characterized in that: The preparation method of the salmon bone phosphopeptide lyophilized powder comprises the following steps: dissolving the salmon bone peptide lyophilized powder in a sodium tripolyphosphate solution to form a mixed system, adjusting the pH to 5.0 and then freeze-drying the system to obtain a lyophilized intermediate product; incubating the obtained lyophilized intermediate product under specific temperature and humidity conditions, and redissolving, dialyzing, and freeze-drying the system again after the incubation is completed to obtain the salmon bone phosphopeptide lyophilized powder.

6. The method for preparing zinc-chelated salmon bone phosphopeptide according to claim 1, characterized in that: The incubation parameters are: relative humidity of 70-85%, temperature of 40-55° C., and incubation time of 10-15 hours.

7. The method for preparing zinc-chelated salmon bone phosphopeptide according to claim 1, characterized in that: The chelating reaction conditions are as follows: adjusting the pH of the reaction system to a range of 7.0-9.0 and performing the reaction by magnetic stirring.

8. The method for preparing zinc-chelated salmon bone phosphopeptide according to claim 1, characterized in that: The ethanol precipitation step uses anhydrous ethanol, and the volume ratio of anhydrous ethanol to the volume of the complex solution is 3:1; The molecular weight cut-off of the dialysis bag used for dialysis was 3500 Da.

9. A zinc-chelated salmon bone phosphopeptide, characterized in that: The zinc-chelated salmon bone phosphopeptide is prepared by the preparation method of claim 1.

10. A zinc-supplemented fish paste, characterized in that: Contains the zinc-chelated salmon bone phosphopeptide as claimed in claim 9, wherein the mass fraction of the zinc-chelated salmon bone phosphopeptide added is 0.15%.

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