Preparation method of novel zinc supplementing preparation with hydrogel as carrier

Abstract

The invention discloses a preparation method of a novel zinc supplementing preparation with hydrogel as a carrier, and belongs to the field of food. The preparation method comprises the following steps: by taking commercially available fish skin gelatin as a raw material and adding sodium alginate as an auxiliary agent, firstly forming pH response type hydrogel through a self-assembly effect between the gelatin and the sodium alginate, then soaking the hydrogel in a zinc sulfate solution in combination with a Hough-Merster effect, and strengthening a gel structure by utilizing an effect of sulfate radicals, so as to prepare the hydrogel. Zinc ions are loaded in the hydrogel through permeation, so that a novel zinc supplementing preparation taking the hydrogel as a carrier is prepared. The hydrogel prepared by the method has certain pH responsiveness, the gel structure cannot be disintegrated in a stomach environment, zinc ions wrapped in the hydrogel can be protected from being interfered by the stomach environment and can be released in an intestinal environment, and the technical bottleneck problem of zinc supplement product development is solved.

Description

Technical Field

[0001] The invention belongs to the field of food and relates to a method for preparing a zinc supplement preparation, in particular to a method for preparing a novel zinc supplement preparation using a hydrogel as a carrier. Background Art

[0002] Zinc is one of the essential trace elements for the human body. It is an important component of transcription factors and enzymes and has important physiological functions. The daily requirement of zinc for adults is about 8-11 mg. Once the body is deficient in zinc, the appetite will be greatly reduced, and symptoms such as loss of appetite and loss of appetite will occur easily. Long-term zinc deficiency will also lead to a decrease in the body's immunity and greatly increase the chance of illness. However, according to statistics, 17% of the world's population still faces the risk of insufficient zinc intake, especially the population in developing countries.

[0003] Taking zinc supplements can improve zinc deficiency to a certain extent. At present, the zinc supplements on the market mainly include inorganic zinc preparations, such as zinc sulfate, zinc oxide, etc. These products will combine with gastric acid in the body to produce strong corrosive zinc chloride, which has a strong irritating effect on the gastrointestinal tract; organic zinc supplements such as licorice zinc and zinc gluconate, etc. These zinc supplements are weak acid and weak base salts, which will still irritate the stomach and intestines, and the high zinc content can antagonize the absorption of other trace elements such as calcium and iron. Long-term use can lead to symptoms such as calcium deficiency and anemia; protein-bound zinc, such as amino acid chelated zinc and peptide chelated zinc, etc. The preparation steps of these products are cumbersome and difficult to control, and some peptides have obvious allergenicity. New zinc supplements are urgently needed to be developed.

[0004] The main absorption site of zinc is in the small intestine, but zinc is unstable in the stomach environment. Zinc ions can easily combine with gastric acid in the body to produce strong corrosive zinc chloride, which irritates the gastrointestinal tract and easily causes side effects such as nausea and vomiting. Therefore, it is urgent to find a carrier to encapsulate zinc ions so that zinc ions can pass smoothly through the stomach and be released in the small intestine. This is of great significance for reducing the side effects of zinc supplementation and improving the efficiency of zinc supplementation. Summary of the invention

[0005] Zinc ions easily combine with gastric acid to produce strong zinc chloride corrosive agent, irritating the gastrointestinal tract, resulting in the existing zinc supplement products causing nausea, vomiting and other side effects. The purpose of the present invention is to propose a preparation method of a novel zinc supplement preparation using hydrogel as a carrier.

[0006] In order to achieve the above object, the first aspect of the present invention is to provide a method for preparing a novel zinc supplement preparation using hydrogel as a carrier, the preparation method comprising the following steps:

[0007] S1. Preparation of gelatin-sodium alginate mixed solution: Weigh gelatin and sodium alginate solid powders respectively, add deionized water to mix, and stir until gelatin and sodium alginate are completely dissolved, specifically stirring at 50-70° C. for 40-60 minutes to obtain a gelatin-sodium alginate mixed solution, so that the mass concentration of gelatin is 6-8wt%, and the mass concentration of sodium alginate is 2-4wt%. Subsequently, the gelatin-sodium alginate mixed solution is placed in a centrifuge with a rotation speed of 3000-5000rpm for 5-15 minutes to defoam, and a uniform gelatin-sodium alginate mixed solution without bubbles is obtained.

[0008] S2. Preparation of gelatin-sodium alginate pH responsive hydrogel: pouring the gelatin-sodium alginate mixed solution obtained in step S1 into a mold, and then freezing it at 4-10° C. for 6-24 hours to obtain gelatin-sodium alginate pH responsive hydrogel;

[0009] S3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 5 to 25 wt %;

[0010] S4. Preparation of zinc-loaded gelatin-sodium alginate hydrogel: cut the hydrogel obtained in step S2 into pieces, soak them in the zinc sulfate solution described in S3 at room temperature for 10 to 14 hours, take them out, wash the surface of the hydrogel with water for 2 to 4 times, wipe off the surface water and freeze them again at 4 to 10° C. for 6 to 24 hours to obtain zinc-loaded gelatin-sodium alginate hydrogel.

[0011] In a preferred embodiment, the stirring temperature in step S1 is 60° C., the stirring time is 60 minutes, the centrifuge speed is 4000 rpm, and the centrifugation time is 10 minutes.

[0012] In a preferred embodiment, the gelatin solution in step S1 has a mass concentration of 7 wt %, and the sodium alginate solution has a mass concentration of 3 wt %.

[0013] In a preferred embodiment, the gelatin is selected from one of commercially available or homemade tilapia skin gelatin, cod skin gelatin, sturgeon skin gelatin, and salmon skin gelatin.

[0014] In a preferred embodiment, the freezing temperature in step S2 is 4° C. and the freezing time is 12 hours.

[0015] In a preferred embodiment, the mass concentration of the zinc sulfate solution in step S3 is 25wt%.

[0016] In a preferred embodiment, the hydrogel in step S4 is immersed for 12 hours and washed three times.

[0017] In a preferred embodiment, the temperature at which the washed hydrogel is re-frozen in step S4 is 4° C., and the freezing time is 12 hours.

[0018] In a preferred embodiment, the method for preparing the novel zinc supplement preparation using hydrogel as a carrier comprises the steps of:

[0019] S1. Preparation of gelatin-sodium alginate mixed solution: Weigh gelatin and sodium alginate solid powders respectively, add deionized water to mix, and stir at 60°C for 60 minutes to completely dissolve gelatin and sodium alginate. Subsequently, the gelatin-sodium alginate mixed solution was centrifuged at a speed of 4000 rpm for 10 minutes to defoam, and a uniform gelatin-sodium alginate mixed solution without bubbles was obtained, wherein the mass concentration of gelatin was 7wt%, and the mass concentration of sodium alginate was 3wt%;

[0020] S2. Preparation of gelatin-sodium alginate pH responsive hydrogel: pour the gelatin-sodium alginate mixed solution obtained in step S1 into a mold, and then freeze it at 4° C. for 12 hours to obtain gelatin-sodium alginate pH responsive hydrogel;

[0021] S3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 25 wt %;

[0022] S4. Preparation of zinc-loaded gelatin-sodium alginate hydrogel: cut the hydrogel obtained in step S2 into pieces, soak them in the zinc sulfate solution described in S3 at room temperature for 12 hours, take them out, wash the surface of the hydrogel with water for 3 times, wipe off the surface water and freeze them again at 4° C. for 12 hours to obtain zinc-loaded gelatin-sodium alginate hydrogel.

[0023] The second aspect of the present invention is to provide the zinc supplementation hydrogel prepared by the above method.

[0024] The third aspect of the present invention is to provide food comprising the zinc supplementation hydrogel.

[0025] The fourth aspect of the present invention is to provide application of the zinc supplementation hydrogel in the food field.

[0026] The beneficial effects of the present invention are as follows:

[0027] 1. The preparation method of a novel zinc supplement preparation with hydrogel as a carrier provided by the present invention has simple steps. It only needs to cool the mixed solution of gelatin and sodium alginate at 4°C to form a pH-responsive hydrogel, and then immerse the hydrogel in a zinc sulfate solution to load zinc ions, and then condense it again after washing with deionized water.

[0028] 2. The novel zinc supplement preparation with hydrogel as carrier obtained by the present invention can realize efficient loading of zinc ions. When the mass concentration of gelatin is 7wt% and the mass concentration of sodium alginate is 3wt%, the zinc loading amount of the hydrogel after being immersed in zinc sulfate solution with mass concentrations of 5wt%, 15wt%, and 25wt% is 12.39mg / g, 32.77mg / g, and 52.21mg / g, respectively.

[0029] 3. The present invention provides a method for preparing a novel zinc supplement preparation using hydrogel as a carrier. The prepared hydrogel zinc supplement preparation has a certain pH sensitivity, the gel structure is stable in the gastric environment, and the gel structure is destroyed in the intestinal environment, which can protect zinc ions from interference by gastric juice to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a macroscopic picture of the novel zinc supplement preparation using hydrogel as a carrier prepared in Example 1;

[0031] Figure 2 The swelling behavior pictures of the novel zinc supplement preparation with hydrogel as carrier prepared in Example 1 in PBS solutions of pH 2 and pH 7;

[0032] Figure 3 These are pictures of the hydrogels prepared in Comparative Examples 1, 2, and 3 before and after swelling in a pH 2 PBS solution. DETAILED DESCRIPTION

[0033] The test method for the hydrogel in the embodiment is as follows:

[0034] Hydrogel swelling behavior test: At room temperature, the hydrogel was cut into thin slices and then immersed in 30 ml of pH 2 and pH 7 PBS solutions for 12 hours. The hydrogel was photographed before and after immersion to observe the changes in its morphology before and after swelling.

[0035] The present invention uses commercially available gelatin as the main raw material, and sodium alginate is added as an auxiliary. First, a pH-responsive hydrogel is formed through the self-assembly reaction between gelatin and sodium alginate, and then the hydrogel is immersed in a zinc sulfate solution in combination with the Hofmeister effect to load zinc ions, thereby preparing a new zinc supplement preparation with hydrogel as a carrier. The hydrogel prepared by the method of the present invention has a certain pH responsiveness, which can protect the zinc ions wrapped therein from interference from the gastric environment, and can be released in the intestinal environment, solving the technical bottleneck problem of zinc supplement product development. The preparation method of the new zinc supplement preparation with hydrogel as a carrier is specifically implemented according to the following steps (hereinafter referred to as specific implementation method one):

[0036] 1. Preparation of gelatin-sodium alginate mixed solution: Weigh gelatin and sodium alginate solid powders respectively, add deionized water to mix, and stir at 50-70°C for 40-60 minutes to completely dissolve gelatin and sodium alginate. Subsequently, centrifuge the gelatin-sodium alginate mixed solution at a speed of 3000-5000rpm for 5-15 minutes to defoam, and obtain a uniform gelatin-sodium alginate mixed solution without bubbles, wherein the mass concentration of gelatin is 6-8wt%, and the mass concentration of sodium alginate is 2-4wt%;

[0037] 2. Preparation of gelatin-sodium alginate pH responsive hydrogel: pour the gelatin-sodium alginate mixed solution obtained in step 1 into a mold, and then freeze it at 4-10° C. for 6-24 hours to obtain gelatin-sodium alginate pH responsive hydrogel;

[0038] 3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 5 to 25 wt%;

[0039] 4. Preparation of zinc-loaded gelatin-sodium alginate hydrogel: Cut the hydrogel obtained in step 2 into pieces, soak them in the zinc sulfate solution in step 3 at room temperature for 10 to 14 hours, take them out, wash the surface of the hydrogel with water for 2 to 4 times, wipe off the surface water and freeze them again at 4 to 10° C. for 6 to 24 hours to obtain zinc-loaded gelatin-sodium alginate hydrogel.

[0040] Specific embodiment 2: This embodiment is different from specific embodiment 1 in that gelatin and sodium alginate are stirred at 60° C. for 60 minutes in step 1. Other steps and parameters are the same as those in specific embodiment 1.

[0041] Specific implementation method 3: This implementation method is different from specific implementation methods 1 to 2 in that the centrifuge speed in step 1 is 4000 rpm and the defoaming time is 10 minutes. The other steps and parameters are the same as those of specific implementation methods 1 to 2.

[0042] Specific embodiment 4: This embodiment is different from specific embodiments 1 to 3 in that the mass concentration of gelatin in step 1 is 7 wt %. The other steps and parameters are the same as those of specific embodiments 1 to 3.

[0043] Specific implementation mode 5: This implementation mode is different from specific implementation modes 1 to 4 in that the mass concentration of sodium alginate in step 1 is 3 wt %. The other steps and parameters are the same as those of specific implementation modes 1 to 4.

[0044] Specific embodiment 6: This embodiment is different from specific embodiments 1 to 5 in that the freezing temperature in step 2 is 4° C. and the freezing time is 12 hours. The other steps and parameters are the same as those of specific embodiments 1 to 5.

[0045] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that the mass concentration of the zinc sulfate solution in step 3 is 25 wt %. The other steps and parameters are the same as those of specific embodiments 1 to 6.

[0046] Specific embodiment 8: This embodiment differs from specific embodiments 1 to 7 in that the hydrogel is immersed in the zinc sulfate solution for 12 hours in step 4, and the surface of the hydrogel is washed with water 3 times. The other steps and parameters are the same as those of specific embodiments 1 to 7.

[0047] Specific embodiment 9: This embodiment differs from specific embodiments 1 to 8 in that the temperature of the hydrogel refreezing in step 4 is 4° C. and the freezing time is 12 hours. The other steps and parameters are the same as those of specific embodiments 1 to 8.

[0048] The present invention is further described below in conjunction with examples, but the embodiments of the present invention are not limited thereto.

[0049] Example 1

[0050] The preparation method of a novel zinc supplement preparation using hydrogel as a carrier in this embodiment is achieved by the following steps:

[0051] S1. Preparation of gelatin-sodium alginate mixed solution: Weigh gelatin and sodium alginate solid powders respectively, add deionized water to mix, and stir at 60°C for 60 minutes to completely dissolve gelatin and sodium alginate. Subsequently, the gelatin-sodium alginate mixed solution was centrifuged at a speed of 4000 rpm for 10 minutes to defoam, and a uniform gelatin-sodium alginate mixed solution without bubbles was obtained, wherein the mass concentration of gelatin was 7wt%, and the mass concentration of sodium alginate was 3wt%;

[0052] S2. Preparation of gelatin-sodium alginate pH responsive hydrogel: pour the gelatin-sodium alginate mixed solution obtained in step S1 into a mold, and then freeze it at 4° C. for 12 hours to obtain gelatin-sodium alginate pH responsive hydrogel;

[0053] S3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 25 wt %;

[0054] S4. Preparation of zinc-loaded gelatin-sodium alginate hydrogel: cut the hydrogel obtained in step S2 into pieces, soak them in the zinc sulfate solution described in S3 at room temperature for 12 hours, take them out, wash the surface of the hydrogel with water for 3 times, wipe off the surface water and freeze them again at 4° C. for 12 hours to obtain zinc-loaded gelatin-sodium alginate hydrogel.

[0055] Figure 1This is a macroscopic picture of the novel zinc supplement preparation with hydrogel as a carrier obtained in this example. It can be seen that the zinc supplement preparation has a smooth surface, a complete structure, and a certain Q elasticity.

[0056] Figure 2 The morphological changes of the novel zinc supplement preparation with hydrogel as carrier obtained in this example after being immersed in PBS solutions of pH 2 and pH 7 for 12 hours show that the morphology of the hydrogel zinc supplement preparation prepared by the preparation method provided by the present invention remains basically unchanged after being immersed in PBS solution of pH 2, but obvious swelling occurs after being immersed in PBS solution of pH 7, and the novel zinc supplement preparation with hydrogel as carrier shows good pH responsiveness.

[0057] Figure 3 The pictures are before and after swelling of the hydrogels prepared in Comparative Examples 1, 2 and 3 in a PBS solution at pH 2. It can be seen that the hydrogels prepared in the comparative examples have been completely dissolved after being soaked in the PBS solution at pH 2, indicating that the hydrogels prepared in the comparative examples cannot reduce the release of zinc ions in the stomach.

[0058] In addition, the zinc ion loading capacity of the hydrogel obtained in this example is 52.21 mg / g.

[0059] Example 2

[0060] The preparation method of a novel zinc supplement preparation using hydrogel as a carrier in this embodiment is achieved by the following steps:

[0061] S1. Preparation of gelatin-sodium alginate mixed solution: Weigh gelatin and sodium alginate solid powders respectively, add deionized water to mix, and stir at 60°C for 60 minutes to completely dissolve gelatin and sodium alginate. Subsequently, the gelatin-sodium alginate mixed solution was centrifuged at a speed of 4000 rpm for 10 minutes to defoam, and a uniform gelatin-sodium alginate mixed solution without bubbles was obtained, wherein the mass concentration of gelatin was 7wt%, and the mass concentration of sodium alginate was 3wt%;

[0062] S2. Preparation of gelatin-sodium alginate pH responsive hydrogel: pour the gelatin-sodium alginate mixed solution obtained in step S1 into a mold, and then freeze it at 4° C. for 12 hours to obtain gelatin-sodium alginate pH responsive hydrogel;

[0063] S3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 15 wt %;

[0064] S4. Preparation of zinc-loaded gelatin-sodium alginate hydrogel: cut the hydrogel obtained in step S2 into pieces, soak them in the zinc sulfate solution described in S3 at room temperature for 12 hours, take them out, wash the surface of the hydrogel with water for 3 times, wipe off the surface water and freeze them again at 4° C. for 12 hours to obtain zinc-loaded gelatin-sodium alginate hydrogel.

[0065] The prepared hydrogel zinc supplement preparation also has good pH responsiveness similar to that of Example 1, and also has a high zinc ion loading capacity of 32.77 mg / g.

[0066] Example 3

[0067] The preparation method of a novel zinc supplement preparation using hydrogel as a carrier in this embodiment is achieved by the following steps:

[0068] S1. Preparation of gelatin-sodium alginate mixed solution: Weigh gelatin and sodium alginate solid powders respectively, add deionized water to mix, and stir at 70°C for 40 minutes to completely dissolve gelatin and sodium alginate. Subsequently, the gelatin-sodium alginate mixed solution was centrifuged at a speed of 3000 rpm for 10 minutes to defoam, and a uniform gelatin-sodium alginate mixed solution without bubbles was obtained, wherein the mass concentration of gelatin was 7wt%, and the mass concentration of sodium alginate was 3wt%;

[0069] S2. Preparation of gelatin-sodium alginate pH responsive hydrogel: pour the gelatin-sodium alginate mixed solution obtained in step S1 into a mold, and then freeze it at 4° C. for 12 hours to obtain gelatin-sodium alginate pH responsive hydrogel;

[0070] S3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 25 wt %;

[0071] S4. Preparation of zinc-loaded gelatin-sodium alginate hydrogel: cut the hydrogel obtained in step S2 into pieces, soak them in the zinc sulfate solution described in S3 at room temperature for 12 hours, take them out, wash the surface of the hydrogel with water for 3 times, wipe off the surface water and freeze them again at 4° C. for 12 hours to obtain zinc-loaded gelatin-sodium alginate hydrogel.

[0072] The prepared hydrogel zinc supplement preparation also has good pH responsiveness similar to that of Example 1.

[0073] Example 4

[0074] The preparation method of a novel zinc supplement preparation using hydrogel as a carrier in this embodiment is achieved by the following steps:

[0075] S1. Preparation of gelatin-sodium alginate mixed solution: Weigh gelatin and sodium alginate solid powders respectively, add deionized water to mix, and stir at 60°C for 60 minutes to completely dissolve gelatin and sodium alginate. Subsequently, the gelatin-sodium alginate mixed solution was centrifuged at a speed of 4000 rpm for 10 minutes to defoam, and a uniform gelatin-sodium alginate mixed solution without bubbles was obtained, wherein the mass concentration of gelatin was 7wt%, and the mass concentration of sodium alginate was 3wt%;

[0076] S2. Preparation of gelatin-sodium alginate pH responsive hydrogel: pour the gelatin-sodium alginate mixed solution obtained in step S1 into a mold, and then freeze it at 4° C. for 6 hours to obtain gelatin-sodium alginate pH responsive hydrogel;

[0077] S3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 25 wt %;

[0078] S4. Preparation of zinc-loaded gelatin-sodium alginate hydrogel: cut the hydrogel obtained in step S2 into pieces, soak them in the zinc sulfate solution described in S3 at room temperature for 12 hours, take them out, wash the surface of the hydrogel with water for 3 times, wipe off the surface water and freeze them again at 4° C. for 6 hours to obtain zinc-loaded gelatin-sodium alginate hydrogel.

[0079] The prepared hydrogel zinc supplement preparation also has good pH responsiveness similar to that of Example 1.

[0080] Example 5

[0081] The preparation method of a novel zinc supplement preparation using hydrogel as a carrier in this embodiment is achieved by the following steps:

[0082] S1. Preparation of gelatin-sodium alginate mixed solution: Weigh gelatin and sodium alginate solid powders respectively, add deionized water to mix, and stir at 60°C for 60 minutes to completely dissolve gelatin and sodium alginate. Subsequently, the gelatin-sodium alginate mixed solution was centrifuged at a speed of 4000 rpm for 10 minutes to defoam, and a uniform gelatin-sodium alginate mixed solution without bubbles was obtained, wherein the mass concentration of gelatin was 8wt%, and the mass concentration of sodium alginate was 2wt%;

[0083] S2. Preparation of gelatin-sodium alginate pH responsive hydrogel: pour the gelatin-sodium alginate mixed solution obtained in step S1 into a mold, and then freeze it at 4° C. for 12 hours to obtain gelatin-sodium alginate pH responsive hydrogel;

[0084] S3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 5 wt %;

[0085] S4. Preparation of zinc-loaded gelatin-sodium alginate hydrogel: cut the hydrogel obtained in step S2 into pieces, soak them in the zinc sulfate solution described in S3 at room temperature for 12 hours, take them out, wash the surface of the hydrogel with water for 3 times, wipe off the surface water and freeze them again at 4° C. for 12 hours to obtain zinc-loaded gelatin-sodium alginate hydrogel.

[0086] The prepared hydrogel zinc supplement preparation also has good pH responsiveness similar to that of Example 1.

[0087] Comparative Example 1

[0088] S1. Preparation of gelatin solution: Weigh gelatin solid powder, add it to deionized water, and stir it at 60°C for 30 minutes to completely dissolve the gelatin. Then, centrifuge the gelatin solution at a speed of 4000 rpm for 10 minutes to defoam, and obtain a uniform gelatin solution without bubbles, wherein the mass concentration of gelatin is 10wt%;

[0089] S2. Preparation of gelatin hydrogel: pouring the gelatin solution obtained in step S1 into a mold, and then freezing at 4° C. for 12 hours to obtain gelatin hydrogel;

[0090] S3. Preparation of zinc sulfate solution: Weigh zinc sulfate powder, add it into deionized water, and stir with a glass rod until the zinc sulfate is completely dissolved to obtain a zinc sulfate aqueous solution with a mass concentration of 5 wt %;

[0091] S4. Preparation of zinc-loaded gelatin hydrogel: cut the hydrogel obtained in step S2 into pieces, soak them in the zinc sulfate solution described in S3 at room temperature for 12 hours, take them out, wash the surface of the hydrogel with water for 3 times, wipe off the surface water and freeze them again at 4°C for 12 hours to obtain zinc-loaded gelatin hydrogel.

[0092] The prepared hydrogel zinc supplement preparation was completely dissolved in the PBS solution at pH 2, and its structure was destroyed. After digestion with simulated gastric juice, all zinc ions were released. It can be seen that the hydrogel prepared in Comparative Example 1 could not reduce the release of zinc ions in the gastric environment.

[0093] Comparative Example 2

[0094] The mass concentration of the zinc sulfate solution in step S3 of comparative example 1 was changed to 15wt%, and the remaining steps were the same as comparative example 1. The prepared hydrogel was also completely dissolved in the solution of pH 2, and the structure was destroyed. After being digested by simulated gastric juice, all zinc ions were released. It can be seen that the hydrogel prepared in comparative example 2 also failed to reduce the release of zinc ions in the gastric environment.

[0095] Comparative Example 3

[0096] The mass concentration of the zinc sulfate solution in step S3 of Comparative Example 1 was changed to 25wt%, and the remaining steps were the same as those of Comparative Example 1. The prepared hydrogel was also completely dissolved in a solution of pH 2, and the structure was destroyed. After being digested by simulated gastric juice, all zinc ions were released. It can be seen that the hydrogel prepared in Comparative Example 3 was also unable to reduce the release of zinc ions in the gastric environment.

[0097] Although the present invention has been disclosed as above in terms of preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the claims.

Claims

1. A method for preparing a novel zinc supplement preparation using hydrogel as a carrier, characterized in that: The preparation method comprises the following steps: Take gelatin and sodium alginate solid powder, add deionized water, stir until gelatin and sodium alginate are completely dissolved, and obtain a gelatin-sodium alginate mixed solution, so that the mass concentration of gelatin is 6-8wt%, and the mass concentration of sodium alginate is 2-4wt%; freeze at 4-10°C for 6-24 hours to obtain a gelatin-sodium alginate pH responsive hydrogel; The gelatin-sodium alginate pH responsive hydrogel is immersed in a zinc sulfate aqueous solution with a mass concentration of 5-25wt% at room temperature for 10-14 hours, the surface is washed with water, wiped dry, and frozen at 4-10°C for 6-24 hours to obtain a zinc-loaded gelatin-sodium alginate hydrogel.

2. The preparation method according to claim 1, characterized in that: The stirring until the gelatin and the sodium alginate are completely dissolved specifically includes: stirring at 50-70° C. for 40-60 minutes to completely dissolve the gelatin and the sodium alginate.

3. The preparation method according to claim 1, characterized in that: After obtaining the gelatin-sodium alginate mixed solution, the method further comprises: defoaming the gelatin-sodium alginate mixed solution by centrifugation at a rotation speed of 3000-5000 rpm for 5-15 minutes to obtain a uniform gelatin-sodium alginate mixed solution without bubbles.

4. The preparation method according to claim 2 or 3, characterized in that: The stirring temperature is 60° C. and the stirring time is 60 minutes; the centrifugal speed is 4000 rpm and the centrifugal time is 10 minutes.

5. The preparation method according to claim 1, characterized in that: The mass concentration of the gelatin solution is 7wt%, the mass concentration of the sodium alginate solution is 3wt%, and the mass concentration of the zinc sulfate solution is 25wt%.

6. The preparation method according to claim 1, characterized in that: The gelatin is selected from any one of commercially available or homemade tilapia skin gelatin, cod skin gelatin, sturgeon skin gelatin, and salmon skin gelatin.

7. The preparation method according to claim 1, characterized in that: The freezing temperature is 4° C. and the time is 12 hours; the immersion time of the hydrogel in the zinc sulfate aqueous solution is 12 hours; and the surface is washed with water for 3 times.

8. A zinc supplementation hydrogel prepared by the preparation method according to any one of claims 1 to 7.

9. A food comprising the zinc supplementation hydrogel according to claim 8.

10. Use of the zinc supplementation hydrogel according to claim 8 in the food field.

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