Mineral-containing high-purity collagen tripeptide and preparation method therefor

Abstract

The present invention relates to the technical field of active substance extraction, and specifically relates to a mineral-containing high-purity collagen tripeptide and a preparation method therefor. A high-purity collagen tripeptide containing mineral elements and having a high hydroxyproline content and no bad flavor, particularly no bitterness is obtained by using a byproduct of aquatic product processing, i.e., fish skin or fish scales, as a raw material, using a one-step enzymolysis method, and performing nanofiltration twice.

Description

A high-purity collagen tripeptide containing minerals and its preparation method

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese Application No. 202410348576.0, filed on March 26, 2024. Said application No. 202410348576.0 is hereby incorporated by reference in its entirety. Technical Field

[0003] The invention belongs to the technical field of active substance extraction, and particularly relates to a high-purity collagen tripeptide containing minerals and a preparation method thereof. Background Art

[0004] Collagen participates in physiological and biochemical behaviors such as cell proliferation, differentiation, migration, and signal transduction, and plays a supporting, repairing, and protective role for tissue cells. However, due to its large molecular weight, it needs to be digested and degraded into free amino acids and oligopeptides before it can be absorbed, and it is absorbed in the form of dipeptides and tripeptides. In addition to being easily absorbed, collagen tripeptides also have physiological activities such as promoting skin growth and repair, promoting cartilage growth and repair, alleviating atherosclerosis, promoting mineral absorption, and anti-oxidation. Studies have reported that after digestion, collagen hydrolysate produces hydroxyproline-containing dipeptides and tripeptides that reach various tissues through the blood circulation and produce corresponding biological activities on skin and joint cells. Therefore, hydroxyproline content is also an important indicator for evaluating the quality of collagen-related products.

[0005] Currently, studies have reported the preparation of collagen tripeptides using ultrasound-assisted enzymatic hydrolysis and fermentation methods. However, these methods are complex, resulting in low extraction and utilization rates of raw materials, and the tripeptide purity is low, resulting in a waste of resources. Furthermore, when mechanical energy is used in conjunction with chemical methods to extract collagen, pollution is likely to occur, the process is complex, and the cost is high, making it unfavorable for the extraction and use of collagen tripeptides.

[0006] For example, Chinese Patent Publication No. CN116162677A discloses a method for preparing high-purity fish skin collagen tripeptides. The specific collagen tripeptide preparation process is as follows: Fish skin gelatin swelling: Prepare a 5-10% by mass solution of fish skin gelatin and heat at 80-100°C for 10 minutes. First step: Enzymatic hydrolysis: Add 5000-8000 U / g of neutral protease at 50-65°C for 2-3 hours. Second step: Add 2000-3000 U / g of papain at 50-65°C for 1.5-2 hours. Ultrafiltration: Filter the hydrolyzed solution using an ultrafiltration membrane with a molecular weight cutoff of 1-2 kDa and a concentration factor of 4-5. First step: Nanofiltration: Use a nanofiltration membrane with a molecular weight cutoff of 800-1000 Da and a concentration factor of 4-5. The second step involves nanofiltration: the nanofiltration membrane has a molecular weight cut-off of 260 Da, and the concentration is performed 3-4 times. After concentration, 1-2 volumes of water are added to wash out the free amino acids and salts. Low-temperature pasteurization is then performed, followed by freeze drying. This preparation method utilizes fish skin gelatin as the raw material, which is relatively expensive. Furthermore, the step-by-step enzymatic hydrolysis method is complex and unsuitable for industrial production. Furthermore, this method uses the enzymatic hydrolyzate directly through the ultrafiltration membrane without separation, which can easily cause clogging of the ultrafiltration membrane during industrial production, reducing its lifespan and increasing energy consumption.

[0007] Therefore, there is a continuing need for high-purity collagen tripeptides and efficient methods for their preparation.

[0008] Summary of the Invention

[0009] In order to solve the defects and deficiencies in the prior art, the present invention provides a high-purity collagen tripeptide containing minerals and a preparation method thereof.

[0010] The purpose of the present invention can be achieved through the following technical solutions:

[0011] In a first aspect, the present invention provides a method for preparing a high-purity collagen tripeptide containing minerals, the method comprising the following steps:

[0012] (1) Pretreatment: The cleaned fish skin or fish scales are added to an alkaline solution of 3-8 times the mass and soaked for 2-6 hours, and then washed with distilled water until neutral, thereby pre-treating the fish skin or fish scales, wherein the alkaline solution is one of sodium hydroxide, potassium hydroxide, sodium carbonate or sodium bicarbonate with a mass concentration of 0.2%-1%;

[0013] (2) Extraction of collagen: pretreated fish skin or fish scales are mixed with purified water at a ratio of 1:1-17, and heated at 85-100°C for 1-7h to obtain a collagen extract;

[0014] (3) Adding mineral salts: Adjust the pH of the collagen extract to 6-10 with sodium hydroxide or hydrochloric acid solution, add 0.1-5% of the mass of the protease to the mineral salts, stir and mix well;

[0015] (4) Enzymolysis: add 1.5-5% of the weight of fish skin or fish scale protease, adjust the temperature to 50-65° C., and perform enzymolysis for 3-8 hours to obtain collagen tripeptide enzymolysis solution;

[0016] (5) Inactivation of enzyme: Heat the enzymatic solution at 90-100°C for 10-15 min and cool to 45-65°C;

[0017] (6) Standing and separation: The enzymatic hydrolyzate was allowed to stand for 30-50 min to separate the residue and precipitate to obtain a primary supernatant. The residue was precipitated at 4000-6000 r / min and centrifuged for 20-30 min to obtain a secondary supernatant. The primary supernatant and the secondary supernatant were mixed;

[0018] (7) Decolorization: The supernatant mixture is decolorized by passing it through an activated carbon fiber membrane;

[0019] (8) Separation and purification: The decolorized solution was separated using a 600-800 Da nanofiltration membrane to remove large molecular peptides and impurities to obtain a small molecular peptide solution, which was then filtered through a nanofiltration membrane with a molecular weight cutoff of 200 Da to remove water, monovalent salts, and free amino acids;

[0020] (9) Freeze-drying: Freeze-drying to obtain collagen tripeptide powder.

[0021] As an optional mode, in the above preparation method, in step (1), the fish skin or fish scales are fish skin or fish scales from tilapia.

[0022] Preferably, in step (1), the cleaned fish skin or fish scales are added to an alkaline solution of 3-6 times the mass thereof and soaked for 2-5 hours, and then washed with distilled water until neutral, to obtain the pretreated fish skin or fish scales, wherein the alkaline solution is one of sodium hydroxide, potassium hydroxide, sodium carbonate or sodium bicarbonate with a mass concentration of 0.4%-0.8%.

[0023] More preferably, in step (1), the cleaned fish skin or fish scales are added to an alkaline solution of 5 times the mass and soaked for 4 hours, and then washed with distilled water until neutral, to obtain the pretreated fish skin or fish scales, wherein the alkaline solution is one of sodium hydroxide, potassium hydroxide, sodium carbonate or sodium bicarbonate with a mass concentration of 0.6%.

[0024] As an optional manner, in the above preparation method, in step (2), the pretreated fish skin or fish scales are mixed with purified water at a ratio of 1:5-10, and heated at 85-95°C for 1-5h to obtain a collagen extract.

[0025] More preferably, in step (2), the pretreated fish skin or fish scales are mixed with purified water at a ratio of 1:8 and heated at 90° C. for 2 h to obtain a collagen extract.

[0026] As an optional method, in the above preparation method, in step (3), the collagen extract is adjusted to a pH of 7-10 with sodium hydroxide or hydrochloric acid solution, and a mineral salt of 0.5-3% by mass of the protease is added, stirred, and mixed evenly, wherein the mineral salt is a hydrochloride combination of zinc ion: magnesium ion: calcium ion = 1:3-6:20-80.

[0027] Preferably, in step (3), the collagen extract is adjusted to pH 8.5 with sodium hydroxide or hydrochloric acid solution, and mineral salts in an amount of 1.5-3% by mass of the protease are added, stirred, and mixed evenly, wherein the mineral salts are hydrochloride salts in a ratio of zinc ion: magnesium ion: calcium ion = 1:3-5:20-50.

[0028] As an optional manner, in the above preparation method, in step (4), the protease is one or a combination of alkaline protease, papain, bromelain, neutral protease, flavor protease, trypsin or pepsin.

[0029] Preferably, the protease is selected from one or more of alkaline protease, papain or neutral protease.

[0030] Preferably, in step (4), 3-5% of the weight of fish skin or fish scale protease is added, the temperature is adjusted to 55° C., and the enzymatic hydrolysis is carried out for 6 hours to obtain a collagen tripeptide hydrolyzate.

[0031] As an optional manner, in the above preparation method, in step (5), the enzymatic hydrolyzate is heated at 90°C for 15 minutes and then cooled to 45°C.

[0032] As an optional method, in the above preparation method, in step (6), the enzymatic hydrolyzate is allowed to stand for 30 minutes, the residue is separated and precipitated to obtain a primary supernatant, the residue is precipitated at 4000 r / min, and centrifuged for 20-30 minutes to obtain a secondary supernatant, and the primary supernatant and the secondary supernatant are mixed.

[0033] In a second aspect, the present invention provides a high-purity collagen tripeptide containing minerals prepared by the preparation method described in the first aspect.

[0034] As an optional manner, in the above-mentioned high-purity collagen tripeptide, the purity of the collagen tripeptide is higher than 75% by mass, the hydroxyproline content is higher than 12%, and there is no bitter smell.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] This invention uses fish skin or scales, a byproduct of aquatic product processing, as raw materials. Through a one-step enzymatic hydrolysis method and two nanofiltration steps, a collagen tripeptide containing mineral elements, high purity, high hydroxyproline content, and no bitterness or other unpleasant flavor is obtained. Specific advantages are reflected in the following aspects:

[0037] (1) Using fish skin or fish scales as raw materials, fish skin or fish scale collagen is targeted hydrolyzed by a one-step enzymatic method to prepare collagen tripeptides. The process is simple and easy to industrialize.

[0038] (2) Adding a combination of mineral salts (e.g., zinc ions, magnesium ions, and calcium ions) to the collagen extract as an enzyme activator increases enzyme activity, improves enzymatic hydrolysis effects, and provides mineral elements with nutritional value.

[0039] (3) Using reusable activated carbon fiber membrane instead of activated carbon powder for decolorization can reduce solid waste and corresponding treatment costs, lower costs, and achieve fluidity and continuity in the decolorization process, thereby improving production efficiency.

[0040] (4) Using two nanofiltration steps, the target molecular weight of collagen peptides is obtained, while the monovalent salt is removed and concentrated, thereby improving the purity of collagen tripeptides and increasing the market competitiveness of the product. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0042] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0043] The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials used in the following examples are commercially available products unless otherwise specified.

[0044] Example 1

[0045] (1) Pretreatment: The cleaned fish skin is immersed in an alkaline solution of 5 times its mass for 4 hours, and then washed with distilled water until neutral, thereby obtaining the pretreated fish skin. The alkaline solution is one of sodium hydroxide, potassium hydroxide, sodium carbonate, or sodium bicarbonate with a mass concentration of 0.6%.

[0046] (2) Extraction of collagen: Mix the pretreated fish skin with purified water at a ratio of 1:8 and heat at 90°C for 2 h to obtain collagen extract.

[0047] (3) Adding mineral salts: Adjust the pH of the collagen extract to 8.5 with sodium hydroxide or hydrochloric acid solution, add 1.5% of the mass of the protease to the mineral salts, stir and mix evenly. The mineral salts are hydrochloride salts with a ratio of zinc ion: magnesium ion: calcium ion = 1:4:30.

[0048] (4) Enzymolysis: add 2.5% alkaline protease and 1.5% neutral protease of the fish skin mass, adjust the temperature to 55°C, and perform enzymolysis for 6 hours to obtain collagen tripeptide hydrolyzate.

[0049] (5) Inactivation of enzyme: Heat the enzymatic solution at 90°C for 15 min and cool to 45°C.

[0050] (6) Standing and separation: The enzymatic hydrolyzate was allowed to stand for 30 minutes, and the residue was separated and precipitated to obtain a primary supernatant. The residue was precipitated at 4000 r / min and centrifuged for 20 minutes to obtain a secondary supernatant. The primary supernatant and the secondary supernatant were mixed.

[0051] (7) Decolorization: The supernatant mixture is decolorized by passing it through an activated carbon fiber membrane.

[0052] (8) Separation and purification: Use a nanofiltration membrane (600-800 Da) to separate the decolorized liquid to remove large molecular peptides and impurities to obtain a small molecular peptide solution, which is then filtered through a nanofiltration membrane with a molecular weight cutoff of 200 Da to remove water, monovalent salts and free amino acids.

[0053] (9) Freeze-drying: Freeze-drying to obtain collagen tripeptide powder.

[0054] Example 2

[0055] (1) Pretreatment: The cleaned fish skin is immersed in an alkaline solution of 5 times its mass for 4 hours, and then washed with distilled water until neutral, thereby obtaining the pretreated fish skin. The alkaline solution is one of sodium hydroxide, potassium hydroxide, sodium carbonate, or sodium bicarbonate with a mass concentration of 0.6%.

[0056] (2) Extraction of collagen: Mix the pretreated fish skin with purified water at a ratio of 1:8 and heat at 90°C for 2 h to obtain collagen extract.

[0057] (3) Adding mineral salts: Adjust the pH of the collagen extract to 8.5 with sodium hydroxide or hydrochloric acid solution, add 1.5% of the mass of the protease to the mineral salts, stir and mix evenly. The mineral salts are hydrochloride salts with a ratio of zinc ion: magnesium ion: calcium ion = 1:4:30.

[0058] (4) Enzymolysis: add 2.5% alkaline protease and 1.5% papain of the fish skin mass, adjust the temperature to 55°C, and perform enzymolysis for 6 hours to obtain collagen tripeptide enzymolysis solution.

[0059] (5) Inactivation of enzyme: Heat the enzymatic solution at 90°C for 15 min and cool to 45°C.

[0060] (6) Standing and separation: The enzymatic hydrolyzate was allowed to stand for 30 minutes to separate the residue and precipitate to obtain a primary supernatant. The residue was precipitated at 4000 r / min and centrifuged for 30 minutes to obtain a secondary supernatant. The primary supernatant and the secondary supernatant were mixed.

[0061] (7) Decolorization: The supernatant mixture is decolorized by passing it through an activated carbon fiber membrane.

[0062] (8) Separation and purification: Use a nanofiltration membrane (600-800 Da) to separate the decolorized liquid to remove large molecular peptides and impurities to obtain a small molecular peptide solution, which is then filtered through a nanofiltration membrane with a molecular weight cutoff of 200 Da to remove water, monovalent salts and free amino acids.

[0063] (9) Freeze-drying: Freeze-drying to obtain collagen tripeptide powder.

[0064] Example 3

[0065] (1) Pretreatment: The cleaned fish skin is immersed in an alkaline solution of 5 times its mass for 4 hours, and then washed with distilled water until neutral, thereby obtaining the pretreated fish skin. The alkaline solution is one of sodium hydroxide, potassium hydroxide, sodium carbonate, or sodium bicarbonate with a mass concentration of 0.6%.

[0066] (2) Extraction of collagen: Mix the pretreated fish skin with purified water at a ratio of 1:8 and heat at 90°C for 2 h to obtain collagen extract.

[0067] (3) Adding mineral salts: Adjust the pH of the collagen extract to 8.5 with sodium hydroxide or hydrochloric acid solution, add 3% of the mass of the protease to the mineral salts, stir and mix evenly. The mineral salts are hydrochloride salts with a ratio of zinc ion: magnesium ion: calcium ion = 1:4:30.

[0068] (4) Enzymolysis: add 2.5% alkaline protease and 1.5% neutral protease of the fish skin mass, adjust the temperature to 55°C, and perform enzymolysis for 6 hours to obtain collagen tripeptide hydrolyzate.

[0069] (5) Inactivation of enzyme: Heat the enzymatic solution at 90°C for 15 min and cool to 45°C.

[0070] (6) Standing and separation: The enzymatic hydrolyzate was allowed to stand for 30 minutes, and the residue was separated and precipitated to obtain a primary supernatant. The residue was precipitated at 4000 r / min and centrifuged for 20 minutes to obtain a secondary supernatant. The primary supernatant and the secondary supernatant were mixed.

[0071] (7) Decolorization: The supernatant mixture is decolorized by passing it through an activated carbon fiber membrane.

[0072] (8) Separation and purification: Use a nanofiltration membrane (600-800 Da) to separate the decolorized liquid to remove large molecular peptides and impurities to obtain a small molecular peptide solution, which is then filtered through a nanofiltration membrane with a molecular weight cutoff of 200 Da to remove water, monovalent salts and free amino acids.

[0073] (9) Freeze-drying: Freeze-drying to obtain collagen tripeptide powder.

[0074] Example 4

[0075] (1) Pretreatment: The cleaned fish skin is immersed in an alkaline solution of 5 times its mass for 4 hours, and then washed with distilled water until neutral, thereby obtaining the pretreated fish skin. The alkaline solution is one of sodium hydroxide, potassium hydroxide, sodium carbonate, or sodium bicarbonate with a mass concentration of 0.6%.

[0076] (2) Extraction of collagen: Mix the pretreated fish skin with purified water at a ratio of 1:8 and heat at 90°C for 2 h to obtain collagen extract.

[0077] (3) Adding mineral salts: Adjust the pH of the collagen extract to 8.5 with sodium hydroxide or hydrochloric acid solution, add 1.5% of the mass of the protease to the mineral salts, stir and mix evenly. The mineral salts are hydrochloride salts with a ratio of zinc ion: magnesium ion: calcium ion = 1:5:40.

[0078] (4) Enzymolysis: add 2.5% alkaline protease and 1.5% neutral protease of the fish skin mass, adjust the temperature to 55°C, and perform enzymolysis for 6 hours to obtain collagen tripeptide hydrolyzate.

[0079] (5) Inactivation of enzyme: Heat the enzymatic solution at 90°C for 15 min and cool to 45°C.

[0080] (6) Standing and separation: The enzymatic hydrolyzate was allowed to stand for 30 minutes, and the residue was separated and precipitated to obtain a primary supernatant. The residue was precipitated at 4000 r / min and centrifuged for 20 minutes to obtain a secondary supernatant. The primary supernatant and the secondary supernatant were mixed.

[0081] (7) Decolorization: The supernatant mixture is decolorized by passing it through an activated carbon fiber membrane.

[0082] (8) Separation and purification: Use a nanofiltration membrane (600-800 Da) to separate the decolorized liquid to remove large molecular peptides and impurities to obtain a small molecular peptide solution, which is then filtered through a nanofiltration membrane with a molecular weight cutoff of 200 Da to remove water, monovalent salts and free amino acids.

[0083] The purity of the tripeptides, hydroxyproline content, absorbance of the decolorized solution and taste of each example are shown in Table 1.

[0084] The enzymes involved in the present invention are all commercially available proteases.

[0085] The present invention utilizes an acid hydrolysis method hydroxyproline kit to determine the hydroxyproline content in collagen tripeptide.

[0086] The purity of collagen tripeptide was determined by high performance liquid chromatography (HPLC).

[0087] Sample processing: Dissolve the sample in mobile phase, filter it through a 0.45 μm filter membrane, and place it in an injection vial.

[0088] Chromatographic conditions: TSKgel gel chromatography column, mobile phase: 40% acetonitrile + 60% ultrapure water + 0.1% trifluoroacetic acid solution, vacuum pump degassing, UV detection wavelength 220nm; column temperature 30°C, flow rate 1mL / min, injection volume 10μL. Different molecular weight standards were used to determine the elution time of the tripeptide, and the ratio of the peak area at the elution time to the total peak area was used to indicate the purity of the tripeptide.

[0089] The absorbance of the decolorizing solution was measured at 550 nm using a microplate reader.

[0090] Comparative Example 1

[0091] The step 7 in Example 1 was changed to adding activated carbon with a mass percentage of 4% of the fish skin to the supernatant, and the mixture was heated at 45° C. for 40 min to decolorize. Other conditions were the same as in Example 1.

[0092] Comparative Example 2

[0093] Step 3 of Example 1 was deleted, the pH of the collagen extract was adjusted to 8.5, no mineral salts were added, and protease was directly added. Other conditions were the same as in Example 1.

[0094] Comparative Example 3

[0095] The mineral salt combination in step 3 of Example 1 was changed to calcium ion hydrochloride, and the other conditions were the same as in Example 1.

[0096] Comparative Example 4

[0097] The mineral salt combination in step 3 of Example 1 was changed to a hydrochloride combination of zinc ion:calcium ion = 1:30, and other conditions were the same as in Example 1.

[0098] The comparative example results are shown in Table 1.

[0099] Table 1 Tripeptide purity, hydroxyproline content, decolorization solution absorbance and taste of each example

[0100] As can be seen from Table 1, the purities of the tripeptides in Examples 1-4 are all higher than 75%. The purities of the tripeptides obtained by the collagen tripeptide preparation methods reported in the disclosed Chinese invention patents CN114634549A and CN103243144B are 32.8% and 12.49%, respectively. Therefore, the purity of the collagen tripeptides prepared by the process of the present invention is significantly improved. The hydroxyproline content is greater than 12%, and there is no bitter smell. Comparative Example 1 uses activated carbon powder for decolorization, and the purity of the tripeptide is lower than that of Example 1. The absorbance value of the decolorization liquid is also slightly higher, indicating that the activated carbon fiber membrane has a better adsorption effect and a better decolorization effect. Compared with Example 1, the purities of the tripeptides in Comparative Examples 2-4 are all reduced, indicating that the combined use of zinc ions, magnesium ions, and calcium ions as protease activators can improve the enzymatic hydrolysis effect.

[0101] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a high-purity collagen tripeptide containing minerals, characterized in that: The preparation method comprises the following steps: (1) Pretreatment: The cleaned fish skin or fish scales are added to an alkaline solution of 3-8 times the mass and soaked for 2-6 hours, and then washed with distilled water until neutral, thereby pre-treating the fish skin or fish scales, wherein the alkaline solution is one of sodium hydroxide, potassium hydroxide, sodium carbonate or sodium bicarbonate with a mass concentration of 0.2%-1%; (2) Extraction of collagen: pretreated fish skin or fish scales are mixed with purified water at a ratio of 1:1-17, and heated at 85-100°C for 1-7h to obtain a collagen extract; (3) Adding mineral salts: Adjust the pH of the collagen extract to 6-10 with sodium hydroxide or hydrochloric acid solution, add 0.1-5% of the mass of the protease to the mineral salts, stir and mix well; (4) Enzymolysis: add 1.5-5% of the weight of fish skin or fish scale protease, adjust the temperature to 50-65° C., and perform enzymolysis for 3-8 hours to obtain collagen tripeptide enzymolysis solution; (5) Inactivation of enzyme: Heat the enzymatic solution at 90-100°C for 10-15 min and cool to 45-65°C; (6) Standing and separation: The enzymatic hydrolyzate was allowed to stand for 30-50 min to separate the residue and precipitate to obtain a primary supernatant. The residue was precipitated at 4000-6000 r / min and centrifuged for 20-30 min to obtain a secondary supernatant. The primary supernatant and the secondary supernatant were mixed; (7) Decolorization: The supernatant mixture is decolorized by passing it through an activated carbon fiber membrane; (8) Separation and purification: The decolorized solution was separated using a 600-800 Da nanofiltration membrane to remove large molecular peptides and impurities to obtain a small molecular peptide solution, which was then filtered through a nanofiltration membrane with a molecular weight cutoff of 200 Da to remove water, monovalent salts, and free amino acids; (9) Freeze-drying: Freeze-drying to obtain collagen tripeptide powder.

2. The preparation method according to claim 1, wherein: In step (1), the fish skin or fish scales are from tilapia.

3. The preparation method according to claim 1, wherein: In step (2), the pretreated fish skin or fish scale is mixed with purified water at a ratio of 1:5-10, and heated at 85-95° C. for 1-5 hours to obtain a collagen extract.

4. The preparation method according to claim 1, wherein: In step (3), the collagen extract is adjusted to pH 7-10 with sodium hydroxide or hydrochloric acid solution, and mineral salts with a mass percentage of 0.5-3% of protease are added and stirred to mix evenly, wherein the mineral salts are hydrochloride salts with a ratio of zinc ion: magnesium ion: calcium ion = 1:3-6:20-80.

5. The preparation method according to claim 1, wherein: In step (4), the protease is one or a combination of alkaline protease, papain, bromelain, neutral protease, flavor protease, trypsin or pepsin.

6. A high-purity collagen tripeptide containing minerals prepared by the preparation method according to any one of claims 1 to 5.

7. The high-purity collagen tripeptide according to claim 6, characterized in that: Calculated by mass percentage, the purity of the collagen tripeptide is higher than 75%, the hydroxyproline content is higher than 12%, and the product has no bitter or fishy smell.

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