Preparation method of wheat gluten protein peptide with low bitterness and high XOD inhibitory activity

Abstract

The invention discloses a preparation method of wheat gluten protein peptide with low bitterness and high XOD inhibitory activity, which comprises the following steps: by taking wet gluten as a raw material, sequentially carrying out enzymolysis by adopting alpha-amylase and glucamylase to remove starch, then carrying out high-activity enzymolysis on the washed enzymatic hydrolysate by utilizing trypsin, and adding flavourzyme to further regulate and control flavor, so as to obtain the wheat gluten protein peptide with low bitterness and high XOD inhibitory activity. And finally, adjusting the pH value of the enzymatic hydrolysate to high alkalinity, and reducing the aggregation of insoluble peptide aggregates in combination with ice-bath ultrasound. The technical problem that low bitterness and XOD inhibitory activity in wheat gluten protein enzymolysis products are difficult to consider at the same time is successfully solved, the proportion of active peptide fragments with the molecular weight smaller than 500 Da in the prepared wheat peptide is larger than 45%, the xanthine oxidase inhibitory activity is larger than 90%, and the bitterness value is lower than 3.5. The enzymolysis effect is greatly improved, the energy consumption is saved, the production cost is reduced, the product profit is improved, and the method can be widely applied to development of uric acid reducing functional food, health care products or medicines.

Description

Technical Field

[0001] This invention belongs to the field of food-derived bioactive peptide development technology, specifically involving a wheat gluten protein peptide prepared from wet gluten with low bitterness and high XOD inhibitory activity, and its application. Background Technology

[0002] Hyperuricemia is a chronic metabolic disease caused by disordered purine metabolism, leading to a blood uric acid concentration exceeding saturation. The search for safe and effective uric acid-lowering functional components is receiving increasing attention. Xanthine oxidase (XOD) is a key rate-limiting enzyme in the uric acid production process; therefore, XOD inhibitors have become a core target for uric acid-lowering drug development. While traditional XOD inhibitors (such as allopurinol and febuxostat) have proven efficacy, they may cause side effects such as liver and kidney damage. Therefore, the development of food-derived XOD-inhibiting peptides is of significant value.

[0003] Many dietary proteins do not inherently possess uric acid-lowering activity. However, through enzymatic hydrolysis or fermentation, these proteins are broken down to release peptides with uric acid-lowering activity. Currently, a large number of highly active XOD-inhibiting peptides have been isolated from various dietary proteins, exhibiting good uric acid-lowering effects. For example, patent publication number CN120699098A discloses the production of uric acid-lowering peptides using corn protein as a raw material. Another example is patent publication number CN118177233A, which discloses a method for producing uric acid-lowering peptides using rice protein as a raw material. These natural peptides can avoid the side effects of synthetic drugs. However, the types of plant-derived uric acid-lowering peptides reported so far are limited, and the development of new plant-derived uric acid-lowering peptides is urgently needed.

[0004] Wheat gluten is high in protein, containing all 15 essential amino acids, making it a nutritious and inexpensive source of plant protein. However, its poor solubility and limited functional properties restrict its high-value utilization. Converting wheat protein into bioactive peptides through enzymatic hydrolysis can effectively increase the added value of products.

[0005] Current research on wheat-derived protein peptides mainly focuses on developing peptides with antioxidant, hypoglycemic, and hypotensive activities. This is primarily because existing methods for preparing protein peptides include single enzymatic hydrolysis, combined enzymatic hydrolysis, and physical methods such as ultrasound-assisted enzymatic hydrolysis and secondary enzymatic hydrolysis. While these methods can release small molecule peptides with uric acid-lowering activity to some extent, they do not achieve ideal results. Specifically, many methods, such as single enzymatic hydrolysis and physical-assisted enzymatic hydrolysis, can increase the release of small molecule peptides to some extent, but the exposure of uric acid-lowering peptides needs improvement, resulting in unsatisfactory uric acid-lowering effects. Furthermore, for wheat protein, protein peptides prepared by enzymatic hydrolysis often have a noticeable bitter taste, severely affecting their application in the food industry. While compound and secondary enzymatic hydrolysis, utilizing enzymes with different functions in combination or in combination, helps reduce bitterness, the active sites of protein peptides with XOD inhibition typically contain regions composed of hydrophobic amino acids (such as valine, leucine, phenylalanine, and tyrosine). These hydrophobic amino acids are the main cause of bitterness in the enzymatic hydrolysis products. Therefore, existing methods struggle to prepare wheat protein peptides that simultaneously possess high XOD inhibition and low bitterness. Furthermore, during the enzymatic hydrolysis process, the continuous generation of hydrophobic peptides inevitably leads to the formation of insoluble peptide aggregates, resulting in a decreased peptide yield. Summary of the Invention

[0006] To address the aforementioned problems, the purpose of this invention is to provide a method for preparing wheat gluten protein peptides with low bitterness and high XOD inhibitory activity, thereby solving the problems of low XOD inhibition rate, heavy bitterness, inability to simultaneously achieve low bitterness and high XOD inhibitory activity, and low yield of protein peptides in existing enzymatic hydrolysis methods.

[0007] To achieve the above objectives, the present invention first provides a method for preparing wheat gluten protein peptides with low bitterness and high XOD inhibitory activity, comprising the following steps: (1) Raw material pretreatment: Wet gluten is used as raw material. After crushing, α-amylase is added for enzymatic hydrolysis, followed by glucoamylase to remove starch. The mixture is washed with water 2-5 times to obtain the pretreated enzymatic hydrolysate. (2) High-activity enzymatic hydrolysis process: Adjust the pH of the pretreated enzymatic hydrolysate in step (1), add trypsin, stir to hydrolyze it to obtain a first enzymatic hydrolysate; (3) Flavor adjustment: Adjust the temperature and pH of the first enzymatic hydrolysate obtained in step (2), add flavor protease, stir continuously, significantly reduce the bitterness of the product by the hydrophobic amino acids at the exocut end, inactivate the enzyme in a boiling water bath, and obtain the enzymatic hydrolysate after inactivation. (4) Removal of peptide aggregates: Cool the enzymatic hydrolysate obtained in step (4), adjust the pH to 9-14, and perform ultrasonic treatment under ice bath conditions; after ultrasonic treatment, adjust the pH to 7 again, centrifuge to collect the supernatant, and dry to obtain wheat gluten peptides.

[0008] In one embodiment of the present invention, the moisture content of the wet gluten in step (1) is 70-75%.

[0009] In one embodiment of the present invention, after crushing in step (1), the wet gluten is heated to 55-60°C and kept warm for 10-30 minutes, and then α-amylase is added for enzymatic hydrolysis. The enzyme activity of α-amylase is 170000 U / g, the amount added is 12-36 U / g starch, and the hydrolysis time is 45-90 minutes.

[0010] The heat preservation treatment after crushing helps to increase the contact area between wet gluten and enzymes, and at the same time, it causes the starch in the wet gluten to gelatinize and destroy the crystal structure, creating favorable conditions for α-amylase to remove starch.

[0011] In one embodiment of the present invention, the activity of glucoamylase is 450,000 U / g, the amount added is 125-375 U / g starch, and the enzymatic hydrolysis time is 0.5-2 h.

[0012] α-Amylase, as the first step in starch removal enzymatic hydrolysis, acts on the α-1,4 glycosidic bonds in starch, converting residual starch in wet gluten into dextrins and oligosaccharides. Glucoamylase, as the second step in starch removal, acts on the α-1,4 glycosidic bonds at the reducing ends of starch molecules, further enzymatically hydrolyzing dextrins and oligosaccharides, thus further increasing the starch removal rate and yielding high-purity wet gluten before the protease reaction.

[0013] In one embodiment of the present invention, in step (2), the pH of the pretreated enzymatic hydrolysate is adjusted to 6.5-8.5 using 1M NaOH, the enzyme activity of trypsin is 250000U / g, and the amount added is 2-6wt% (based on gluten protein content).

[0014] In one embodiment of the present invention, in step (2), the stirring speed is 250-350 rpm and the enzymatic hydrolysis time is 2-2.5 h.

[0015] In one embodiment of the present invention, in step (3), the temperature of the first enzymatic hydrolysate obtained in step (2) is adjusted to 35~55℃, the pH is adjusted to 6~7 using 1M HCl, the enzyme activity of the added flavor protease is 150000 U / g, and the amount added accounts for 2-2.5% (w / v) of the volume of the enzymatic hydrolysate.

[0016] In one embodiment of the present invention, in step (3), the stirring speed is 250-350 rpm, the enzymatic hydrolysis time is 1-2 h, the temperature of the boiling water bath for inactivating the enzyme is 90-100 ℃, and the time is 10-15 min.

[0017] In one embodiment of the present invention, the pH during ultrasonic treatment in step (4) is preferably 10-13, and the ultrasonic time is 5-10 min.

[0018] In one embodiment of the present invention, the drying method in step (4) is selected from any one of freeze drying, vacuum drying, and spray drying.

[0019] The present invention also provides wheat gluten peptides prepared by the above method.

[0020] The present invention also provides the application of the above-mentioned wheat gluten protein peptides in the preparation of functional foods, health products or drugs for the prevention and / or adjuvant treatment of hyperuricemia.

[0021] Beneficial effects: (1) Through research on the prepared active peptides with high XOD inhibition rate, it was found that the activity of XOD inhibitory peptides is related to hydrophobic amino acids. The bitterness of the enzymatic hydrolysate is essentially due to hydrophobic peptides. Therefore, most XOD inhibitory peptide preparation methods cannot achieve both high activity and low bitterness. In this invention, the specificity of trypsin is used to directionally cleave a large number of XOD inhibitory peptides. Then, flavor protease is used to excise the terminal hydrophobic residues of the bitter peptides to prepare wheat peptides with both high XOD inhibitory activity and low bitterness. The specific enzymatic hydrolysis of trypsin efficiently releases hydrophobic peptides with XOD inhibition potential. Subsequently, the flavor protease cleaves the hydrophobic terminal peptide segments to further expose the active sites. This not only greatly improves the XOD inhibitory activity but also effectively reduces the proportion of terminal hydrophobic amino acids, thus effectively reducing bitterness.

[0022] (2) The present invention uses wet gluten as raw material to directly produce wheat peptide powder, which increases the substrate concentration, greatly increases the yield of wheat gluten protein peptides, improves their XOD activity, and eliminates the drying process in the production of gluten powder, reducing costs and broadening the application field of wheat protein.

[0023] (3) The high-activity enzymatic hydrolysis and flavor regulation process parameters of the present invention are highly dependent. Any deviation from the process parameters of any key component will lead to a decrease in XOD inhibition activity or a rebound in bitterness, resulting in a decline in product quality.

[0024] (4) The present invention utilizes ultrasonic-driven pH shift to reduce insoluble peptide aggregates, thereby increasing the yield of wheat peptides and reducing the formation of insoluble peptide aggregates.

[0025] (5) The wheat gluten protein peptides prepared by the present invention are directly enzymatically hydrolyzed from wet gluten, which significantly improves the protein utilization rate. The proportion of peptides with a molecular weight of less than 1500 Da is more than 90%, and the proportion of small peptides with a molecular weight of less than 500 Da is not less than 45%, which significantly increases the peptide yield. The inhibition rate of XOD at 7.2 mg / mL is higher than 90%, and the bitterness value of the product is ≤3.5, which has good sensory characteristics. (6) The enzymes used in this invention are all enzyme preparations widely used in the food industry. The resulting wheat gluten protein peptide products have high yield, low bitterness value, and high content of small molecule peptides, which significantly improves the added value of wheat gluten protein products. Attached Figure Description

[0026] Figure 1 The molecular weight distribution diagram of the wheat gluten protein peptides obtained in Example 1 is shown. Figure 2 The effect of trypsin hydrolysis time on XOD inhibitory activity and bitterness value; Figure 3 The effect of trypsin addition on XOD inhibitory activity and bitterness value; Figure 4 The effect of the amount of flavor protease added on the bitterness value. Detailed Implementation

[0027] The present invention will be further described and illustrated below with reference to specific embodiments. The embodiments described are merely examples of the content of this disclosure and do not limit the scope of the invention. The technical features of each embodiment in the present invention can be combined accordingly, provided that there is no mutual conflict.

[0028] The α-amylase involved in the embodiments of this invention is from Novozymes, with an enzyme activity of 170,000 U / g; the glucoamylase is from Novozymes, with an enzyme activity of 450,000 U / g; the trypsin is from Sinopharm Chemical Reagent Co., Ltd., with an enzyme activity of 250,000 U / g; the alkaline protease is from Novozymes, with an enzyme activity of 280,000 U / g; the papain is from Yuanye, with an enzyme activity of 2,000 U / mg; and the flavor protease is from Maclean Biochemical Technology Co., Ltd., with an enzyme activity of 150,000 U / g.

[0029] Test methods Experimental steps for XOD inhibition rate determination: Add 50 μL of hydrolysate sample and 50 μL of xanthine oxidase (XOD) solution (0.05 U / mL) to a 96-well plate. Incubate at 37°C for 15 min, then add 150 μL of xanthine solution to initiate the reaction. After incubation for 10 min, measure the absorbance at 290 nm. Allopurinol was used as the positive control.

[0030] The XOD inhibition rate is calculated as follows:

[0031] Where A1 is the absorbance value of XOD, xanthine and sample solution; A2 is the absorbance value of xanthine and sample solution; A3 is the absorbance value of solution containing 0.2M pH7.5 buffer, XOD and xanthine; A4 is the absorbance value of buffer and xanthine solution.

[0032] 2. Sensory evaluation Ten participants (five men and five women) with professional sensory training were selected to conduct sensory analysis, using a six-point scale. Quinine standard solutions were prepared at concentrations of 0, 10, 20, 30, 40, 50, and 60 mg / L, representing scores of 0, 1, 2, 3, 4, 5, and 6, respectively; higher scores indicated stronger bitterness. 20 mL samples (0.01 g / mL) were placed in opaque disposable plastic cups and randomly assigned to members of the sensory panel for tasting. Purified water and unsalted biscuits were provided before each test.

[0033] Example 1 A method for preparing low-bitter wheat gluten protein XOD inhibitory peptide using wet gluten as raw material, the specific steps of which are as follows: (1) Raw material pretreatment: Wet gluten is used as raw material. After crushing it, it is directly heated to 60℃ and kept warm for 20 minutes. 24 U / g (calculated as starch) α-amylase is added for 1 hour of enzymatic hydrolysis. Then 250 U / g (calculated as starch) glucoamylase is added to continue enzymatic hydrolysis for 45 minutes. After the enzymatic hydrolysis is completed, it is washed with water 3 times until the solution is basically clear. (2) High-activity enzymatic hydrolysis process: Adjust the temperature to 37℃ and pH to 8.5, add 10000U / g trypsin for reaction, and stir continuously at 300rpm for 250min. Keep the temperature and pH constant during the enzymatic hydrolysis process to fully release peptides with XOD inhibitory activity. (3) Flavor adjustment: Adjust the temperature of the enzymatic hydrolysate to 50℃, adjust the pH to 7, add 2% (w / v) of flavor protease in the volume of the enzymatic hydrolysate, stir continuously for 1 hour to cleave the terminal hydrophobic amino acids, significantly reduce the bitterness of the product, and then inactivate the enzyme in a boiling water bath for 10 minutes. (4) Removal of peptide aggregates: Cool the enzymatic hydrolysate to room temperature, raise the pH to 12, and sonicate on an ice bath for 10 min; after sonication, adjust the pH to 7 again, centrifuge and take the supernatant to obtain wheat gluten peptides.

[0034] The molecular weight distribution of the wheat peptides prepared in Example 1 was determined using high-performance liquid chromatography-gel chromatography. The results are as follows: Figure 1As shown, the wheat peptides contain 92.99% of the total components with a molecular weight of less than 1500 Da, 78.32% of the total components with a molecular weight of 1000 Da, and 46.24% of the total components with a molecular weight of less than 500 Da. This indicates that the product is mainly composed of small molecule peptides, and the enzymatic hydrolysis of wet gluten significantly improves the yield of small molecule peptides.

[0035] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that step (4) is omitted, and wheat gluten peptides are obtained after enzyme inactivation in step (3).

[0036] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that in step (4), the pH is not adjusted, and the enzymatic hydrolysate is directly subjected to ultrasonic treatment to obtain wheat gluten peptides.

[0037] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that step (3) is omitted.

[0038] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that, in step (3), alkaline protease is used instead of flavor protease.

[0039] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that in step (3), papain is used to replace flavor protease.

[0040] Comparative Example 6 The difference between Comparative Example 6 and Example 1 is that the flavor protease was replaced with β-cyclodextrin, and the amount added was 1.5% (w / v) of the volume of the enzymatic hydrolysate. After addition, the mixture was stirred continuously at 40°C for 1 h, and other conditions were the same as in Example 1.

[0041] Comparative Example 7 The difference between Comparative Example 7 and Example 1 is that the flavor protease was replaced with sec-butanol, which was added to the enzymatic hydrolysate at a volume ratio of 1:1 (v:v), and stirred at 25°C for 30 min. Other conditions were the same as in Example 1.

[0042] Comparative Example 8 The difference between Comparative Example 8 and Example 1 is that trypsin was replaced with alkaline protease, the enzymatic hydrolysis temperature was adjusted to 55°C, the pH was adjusted to 8.5, and other conditions were the same as in Example 1.

[0043] Comparative Example 9 The difference between Comparative Example 9 and Example 1 is that trypsin was replaced with neutral protease, the enzymatic hydrolysis temperature was adjusted to 50°C, the pH was adjusted to 8.0, and other conditions were the same as in Example 1.

[0044] Comparative Example 10 The difference between Comparative Example 10 and Example 1 is that trypsin was replaced with a complex protease, the enzymatic hydrolysis temperature was adjusted to 50°C, the pH was adjusted to 7.0, and other conditions were the same as in Example 1.

[0045] Comparative Example 11 The difference between Comparative Example 11 and Example 1 is that in step (2), the enzymatic hydrolysis time of trypsin is 3 hours, and other conditions are the same as in Example 1.

[0046] Comparative Example 12 The difference between Comparative Example 12 and Example 1 is that in step (2), the amount of trypsin added is 14000 U / g, and the other conditions are the same as in Example 1.

[0047] Comparative Example 13 The difference between Comparative Example 13 and Example 1 is that in step (3), the proportion of flavor protease added is 2.5%, and other conditions are the same as in Example 1.

[0048] Comparative Example 14 The difference between Comparative Example 14 and Example 1 is that in step (2), trypsin and flavor protease are added to the reaction system at the same time, and step (3) is omitted.

[0049] Table 1. XOD inhibition rate and bitterness value of wheat gluten protein peptides obtained in Example 1 and Comparative Examples 3-14

[0050] The wheat gluten peptides obtained in Example 1 and Comparative Examples 1-14 were tested accordingly. Table 1 shows the XOD inhibition rate and bitterness value data of the wheat gluten peptides. As can be seen from Table 1, the sample in Example 1 showed the best overall effect in terms of enzyme inhibition rate and bitterness value. Table 1 also shows that in Comparative Example 3, without the use of flavor protease, the bitterness value increased to 5.5, indicating that flavor protease is key to controlling bitterness. In Comparative Examples 4 and 5, alkaline protease and papain were used to replace the flavor protease, respectively, resulting in a significant decrease in activity and a rebound in bitterness, indicating that using alkaline protease or papain can cause a loss of peptide activity. In Comparative Example 6, the bitterness value significantly decreased to 2.7 after using β-cyclodextrin, but its encapsulation effect may have simultaneously masked the contact between the active peptide and the XOD enzyme, leading to a sharp decrease in activity. In Comparative Example 7, the activity significantly decreased after using sec-butanol, indicating that sec-butanol's removal of hydrophobic peptides affected the activity. These results indicate that none of these four flavor regulation methods are suitable for preparing high-activity, low-bitterness XOD-inhibiting peptides. This further illustrates the advantages of flavor proteases in maintaining activity and reducing bitterness.

[0051] Comparative Examples 8, 9, and 10 replaced trypsin with alkaline, neutral, and complex proteases, respectively. The results showed that the change in enzyme type significantly reduced XOD inhibitory activity and increased bitterness values. This indicates that trypsin can specifically cleave the carboxyl terms of arginine and lysine, and can directionally hydrolyze a large number of peptides with basic amino acids at the C-terminus and a core sequence rich in hydrophobic amino acids. Furthermore, the resulting bitter peptides are more easily removed by flavor proteases. Comparative Examples 11 and 12 investigated the effects of trypsin dosage and hydrolysis time, respectively. Figure 2 As shown, if the enzymatic hydrolysis time is too short (1-2 h), the release of active peptides is insufficient, resulting in a low inhibition rate; if the enzymatic hydrolysis time is too long (2.5-3 h), excessive enzymatic hydrolysis produces too many small molecule peptides, leading to a high bitterness. In Comparative Example 11, the trypsin hydrolysis time was 3 h, which resulted in a decrease in the XOD inhibition rate and a rebound in the bitterness value, indicating that 2-2.5 h of enzymatic hydrolysis is the optimal time for trypsin hydrolysis. Figure 3 The results showed that too low a trypsin dosage resulted in incomplete enzymatic hydrolysis and low activity; while too high a dosage, such as in Comparative Example 12 where the trypsin dosage was 140,000 U / g, led to further enzymatic hydrolysis of the active peptides, significantly reducing their activity and increasing bitterness. This demonstrates that the optimal trypsin dosage range is around 10,000 U / g. In conclusion, any change in any parameter of the high-activity enzymatic hydrolysis process will lead to a decrease in activity or an increase in bitterness.

[0052] Comparative Example 13 further adjusted the amount of flavor protease added, increasing it to 2.5%. Although the bitterness decreased, the active peptides were likely destroyed due to excessive enzymatic hydrolysis, and the XOD inhibition rate dropped to 76.12%. This indicates that excessive addition of flavor protease may lead to excessive hydrolysis of active peptides. This can be seen from... Figure 4 The results showed that the appropriate addition amount of flavor protease is approximately 2%. Comparative Example 14 changed the order of addition of trypsin and flavor protease, combining the two-step reaction into one step. The XOD inhibition rate decreased to 31.18%, and the bitterness value also increased to 4.6, indicating that the change in the enzymatic hydrolysis order affects the generation of the target active peptide, thereby affecting product quality.

[0053] Table 2. Yield of wheat gluten protein peptides and proportion of insoluble peptides

[0054] As shown in Table 2, the peptide yield of Example 1 was 92.61%, and the proportion of insoluble peptides was 8.35%. Comparative Example 2, without pH shifting, showed a significantly lower peptide yield compared to Example 1, but a significantly higher peptide yield compared to Comparative Example 1. This indicates that ultrasonic treatment can effectively improve the yield of wheat XOD-inhibiting peptides. After ultrasonic and pH shifting, the peptide yield of Comparative Example 1 was significantly lower than that of Example 1, down to 80.28%, while the proportion of insoluble peptides increased to 17.62%. This indicates that ultrasonic treatment combined with pH shifting can significantly improve peptide yield and reduce the formation of insoluble peptide aggregates. Furthermore, compared to Comparative Examples 1 and 2, the XOD-inhibiting activity of the product in Example 1 was also improved after ultrasonic treatment and pH shifting, indicating that the depolymerization of insoluble peptide aggregates allowed more active peptides to dissolve in the product.

[0055] Table 3 shows the XOD inhibition rate of wheat gluten peptides prepared in Example 1 at different concentrations, and compares it with the XOD inhibition rate of commercially available uric acid-lowering peptides. As can be seen from Table 3, the XOD inhibition rate of wheat peptides at high concentrations is greater than 90%, which is significantly higher than that of commercially available goose muscle peptides and megoxatriol peptides.

[0056] Table 3. XOD inhibition rate of wheat peptides at different concentrations

[0057] In summary, this invention utilizes wet gluten as raw material, employing a highly active enzymatic hydrolysis process and a dual enzymatic hydrolysis method involving flavor regulation. By using pH-shifted driven ultrasound to reduce peptide insoluble aggregates, a synergistic and efficient high-yield, low-bitterness wheat gluten protein XOD inhibitory peptide preparation scheme is formed. This method not only effectively increases substrate concentration, reduces production costs, and improves peptide yield, but also removes bitterness while preparing highly active XOD inhibitory peptides.

[0058] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A method for preparing a wheat gluten protein peptide with low bitterness and high XOD inhibitory activity, characterized in that, Includes the following steps: (1) Raw material pretreatment: Wet gluten is used as raw material. After crushing, it is heated and then α-amylase is added for enzymatic hydrolysis. Then glucoamylase is added to remove starch. The mixture is washed with water 2 to 5 times to obtain the pretreated enzymatic hydrolysate. (2) High-activity enzymatic hydrolysis process: Adjust the pH of the pretreated enzymatic hydrolysate in step (1), add trypsin, stir to hydrolyze it to obtain a first enzymatic hydrolysate; (3) Flavor adjustment: Adjust the temperature and pH of the first enzymatic hydrolysate obtained in step (2), add flavor protease, stir continuously, significantly reduce the bitterness of the product by the hydrophobic amino acids at the exocut end, inactivate the enzyme in a boiling water bath, and obtain the enzymatic hydrolysate after inactivation. (4) Removal of peptide aggregates: Cool the enzymatic hydrolysate obtained in step (4), adjust the pH to 9-14, and perform ultrasonic treatment under ice bath conditions; after ultrasonic treatment, adjust the pH to 7 again, centrifuge to collect the supernatant, and dry to obtain wheat gluten peptides.

2. The preparation method according to claim 1, characterized in that, The moisture content of the wet gluten in step (1) is 70-75%. After crushing in step (1), the wet gluten is first heated to 55-60℃ and kept warm for 10-30 minutes.

3. The preparation method according to claim 1, characterized in that, The enzyme activity of α-amylase is 170,000 U / g, the amount added is 12~36 U / g starch, and the enzymatic hydrolysis time is 45~90 min.

4. The preparation method according to claim 1, characterized in that, The enzyme activity of glucoamylase is 450,000 U / g, the amount added is 125~375 U / g starch, and the enzymatic hydrolysis time is 0.5~2h.

5. The preparation method according to claim 1, characterized in that, In step (2), the pH of the pretreated enzymatic hydrolysate is adjusted to 6.5-8.5 using 1M NaOH, the enzyme activity of trypsin is 250000U / g, the amount of trypsin added accounts for 2-6% of the gluten protein content, the stirring speed is 250-350rpm, and the enzymatic hydrolysis time is 2-2.5h.

6. The preparation method according to claim 1, characterized in that, In step (3), the temperature of the first enzymatic hydrolysate obtained in step (2) is adjusted to 35~55℃, the pH is adjusted to 6~7, the enzyme activity of the added flavor protease is 150000 U / g, and the amount added accounts for 2~2.5% of the volume of the enzymatic hydrolysate.

7. The preparation method according to claim 1, characterized in that, In step (3), the stirring speed is 250~350 rpm, the enzymatic hydrolysis time is 1~2 h, the temperature of the boiling water bath for inactivating the enzyme is 90~100℃, and the time is 10~15 min.

8. The preparation method according to claim 1, characterized in that, In step (4), the pH during ultrasonic treatment is 10-13, the ultrasonic time is 5-10 min, and the drying is any one of freeze drying, vacuum drying, or spray drying.

9. Wheat gluten peptides prepared by any one of claims 1 to 8.

10. The use of the wheat gluten protein peptide according to claim 9 in the preparation of functional foods, health products or drugs for the prevention and / or adjunctive treatment of hyperuricemia.

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