A method for preparing anti-aging wheat starch

Abstract

The application provides a preparation method of anti-aging wheat starch; high-temperature-resistant alpha-amylase, papain and saccharifying enzyme are used for enzymolysis of young leaves of highland barley; the product after the enzymolysis is subjected to first solid-liquid separation, and residues are collected; the residues are added with xylanase and cellulase for enzymolysis; the product is cooled to room temperature and subjected to second solid-liquid separation; polysaccharide in the liquid is precipitated by ethanol; the precipitate is redissolved, dialyzed, concentrated by rotary evaporation and vacuum freeze-dried to obtain polysaccharide; the polysaccharide is dissolved in water to obtain a uniform polysaccharide solution; wheat starch is added into the polysaccharide solution; the mixture is stirred and uniformly mixed to obtain a mixed system; the mixed system is heated and gelatinized; the product is obtained by cooling at room temperature and freeze-drying; and the anti-aging wheat starch prepared based on the polysaccharide obtained from the enzyme residue can be used for making various snacks, such as crystal moon cake crust, shrimp dumplings, powder cakes, rice rolls and the like, and can enhance the anti-aging function of food.

Description

Technical Field

[0001] This invention relates to the field of food technology, and more specifically, to a method for preparing anti-aging wheat starch. Background Technology

[0002] Wheat starch, also known as clear starch or wheat flour, is a gluten-free flour. It can be used to make various pastries, such as crystal mooncake crusts, shrimp dumplings, rice noodle rolls, and rice rolls. Wheat starch is also used as a raw material in the production of instant noodles, sausages, ice cream, and other foods. Starchy foods undergo retrogradation, which causes most foods to harden and even become powdery, significantly reducing the quality of products like crystal mooncakes, shrimp dumplings, rice noodle rolls, and rice rolls. This phenomenon is attributed to the expansion of starch granules in a hydrothermal environment during processing, which loosens the starch molecule structure, allowing water molecules to enter and associate with it. After the food is cooked, during cooling and storage, the linear portions of amylose and amylopectin tend to align parallel to each other, and stable hydrogen bonds reform between starch molecules, returning them from an amorphous state to a crystalline state. This results in a system with the lowest energy and greater stability. Retrogradation occurs as molecules rearrange themselves, reducing water absorption and causing water to seep out, leading to moisture loss, increased hardness, and a significant decline in quality.

[0003] To further improve the properties and nutritional functions of starch-based foods, industrial processes involve physical, chemical, and enzymatic modifications. However, chemical modifications pose potential food safety risks, while enzymatic modifications can lead to excessive hydrolysis, loss of the desired texture, or reduced resistance to retrogradation. Therefore, finding a healthier, safer, and faster method to reduce starch retrogradation is a current research hotspot. Many natural substances, such as amino acids and polyphenols, are often used to improve starch properties. Plant polysaccharides, as important bioactive components, possess various beneficial health effects, including antioxidant, antibacterial, and antitumor properties, and are widely used in the food, biological, pharmaceutical, and chemical industries. Barley grass, the seedling of barley at a height of 20-30 cm, is a food with both medicinal and culinary uses, recorded in Chinese pharmacopoeias such as *Puji Fang* and *Compendium of Materia Medica*. Highland barley, also known as naked barley, is a type of barley. Research data shows that polysaccharides from young highland barley leaves have effects such as fat reduction, cancer inhibition, and antioxidant properties. This invention is the first to utilize polysaccharides, a functional component in young barley leaves, to slow down the aging rate of wheat starch, thereby preparing an anti-aging wheat starch that can be widely used in food production and improve the quality of starch-based foods. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for preparing anti-aging wheat starch. This invention, for the first time, utilizes a combined xylanase and cellulase method to extract soluble polysaccharides from the enzyme extraction residue of young barley leaves. These polysaccharides are mainly composed of arabinoxylan and pectin polysaccharides rich in rhamnose-galacturonic acid polysaccharide type I (RG-I). Among these, arabinoxylan is a branched polymer, and RG-I is also highly branched. In the mixed system, the complex entanglement between the two polymers, arabinoxylan and RG-I-rich pectin polysaccharides, forms a network structure that increases the steric hindrance between starch molecules, reducing the probability of ordered rearrangement of starch molecules and thus inhibiting starch aging. Simultaneously, the hydroxyl groups of the polysaccharides in the young barley leaf residue have a stronger ability to form hydrogen bonds with the hydroxyl groups of starch molecules than the ability to form hydrogen bonds between the hydroxyl groups of starch molecules, thereby interfering with the formation of microcrystalline bundle hydrogen bonds in starch molecules and further delaying starch aging.

[0005] The objective of this invention is achieved through the following solution:

[0006] This invention provides a method for preparing anti-aging wheat starch, characterized by comprising the following steps:

[0007] S1. The young leaves of highland barley are enzymatically hydrolyzed with heat-resistant α-amylase, papain and saccharifying enzyme. After solid-liquid separation, the residue is collected. The residue is mixed with water, and xylanase and / or cellulase are added for enzymatic hydrolysis. After solid-liquid separation, the polysaccharide in the solution is precipitated with ethanol. The precipitate is redissolved, dialyzed, concentrated by rotary evaporation, and then freeze-dried under vacuum to obtain the polysaccharide.

[0008] S2. Dissolve the polysaccharide in water to obtain a polysaccharide solution. Add starch to the polysaccharide solution and stir to obtain a mixed system. Heat the mixed system to gelatinize, cool it at room temperature, and freeze-dry it to obtain the finished product.

[0009] In one embodiment of the present invention, in step S1, the young barley leaves are mixed with water at a solid-liquid ratio of 1:30-40.

[0010] As one embodiment of the present invention, in step S1, the enzyme dosage per gram of barley tender leaves is: 200-250U of thermoresistant α-amylase, 1000-1500U of papain, and 250-300U of saccharifying enzyme.

[0011] In one embodiment of the present invention, in step S1, the mixture is first hydrolyzed with thermostable α-amylase in a water bath at 70–80°C for 1–2 hours; then papain and saccharifying enzyme are added and hydrolyzed in a water bath at 55–65°C for 2–3 hours. After cooling to room temperature, the mixture is centrifuged. 200–250 U of thermostable α-amylase is added to the mixture and the mixture is incubated in a water bath at 70–80°C for 1–2 hours to remove starch from the young barley leaves, hydrolyzing the starch into dextrin and oligosaccharides. Alternatively, 1000–1500 U of papain and 250–300 U of saccharifying enzyme can be added simultaneously and the mixture is incubated in a water bath at 55–65°C for 2–3 hours to remove protein from the young barley leaves, hydrolyzing the protein into soluble peptides. The α-amylase product in the mixture is further hydrolyzed to generate glucose, which is then removed by subsequent centrifugation. Alternatively, 1000–1500 U of papain and 250–300 U of saccharifying enzyme can be added separately, and enzymatic hydrolysis can be carried out in a water bath at 55–65°C for 2–3 hours.

[0012] In one embodiment of the present invention, step S1, after solid-liquid separation and collection of residue, further includes the steps of drying the residue, pulverizing and sieving it. The residue is dried and then pulverized to a mesh size of 60-80 and sieved. The drying temperature of the residue is 37-40°C, and the drying time is 24-48 hours.

[0013] In one embodiment of the present invention, in step S1, the residue is mixed with water at a solid-liquid ratio of 1:25-30.

[0014] As one embodiment of the present invention, in step S1, the enzyme dosage per gram of residue is: 700-800 U xylanase and 300-400 U cellulase.

[0015] As one embodiment of the present invention, in step S1, after the residue is mixed with water, xylanase and / or cellulase are added at pH 5.0 to 5.5 and the mixture is placed in a water bath at 50 to 55°C for 3 to 4 hours; after cooling to room temperature, it is centrifuged.

[0016] In one embodiment of the present invention, in step S1, the liquid is rotary evaporated at 50-60°C for 0.5-1 h, and the concentrate is freeze-dried under vacuum at -40--50°C for 12-24 h.

[0017] In some embodiments, in step S1, the residue is mixed with water at a solid-liquid ratio (1:25-30), the pH is adjusted to 5.0-5.5 with 0.561 mol / L hydrochloric acid, 700-800 U xylanase and 300-400 U cellulase are added, and the mixture is incubated in a water bath at 50-55°C for 3-4 hours. After cooling to room temperature, the mixture is centrifuged, and the supernatant is precipitated with 3-4 times the volume of 95% ethanol.

[0018] As one embodiment of the present invention, the supernatant obtained after enzymatic hydrolysis and centrifugation of the residue is precipitated with 3 to 4 times the amount of 95% ethanol.

[0019] As one embodiment of the present invention, the dialysis-retained polysaccharide has a molecular weight cutoff greater than 3500 Da.

[0020] In one embodiment of the present invention, in step S2, 1 to 5 parts of the polysaccharide are dissolved in 1000 to 1500 parts of water to obtain a polysaccharide solution.

[0021] In one embodiment of the present invention, in step S2, wheat starch is added to the polysaccharide solution according to a mass ratio of polysaccharide to wheat starch of 1-5:95-99.

[0022] In one embodiment of the present invention, in step S2, the heating and gelatinization is performed by heating at 90–95°C for 15–20 minutes. In step S2, the mixture is cooled to room temperature for 12–24 hours and then freeze-dried to obtain the finished product.

[0023] In some embodiments, in step S2, wheat starch is added to the polysaccharide solution according to the mass ratio of polysaccharide to wheat starch being 1-5:95-99, and the mixture is stirred and mixed to obtain a mixed system. The mixed system is heated at 90-95°C for 15-20 minutes, gelatinized, cooled at room temperature for 12-24 hours, and freeze-dried to obtain the finished product.

[0024] In step S1 of the present invention, soluble polysaccharides are extracted from the residue of young barley leaves by a combination of xylanase and cellulase, thereby degrading the cellulose and hemicellulose in the residue and degrading the insoluble polysaccharides into soluble polysaccharides, to obtain arabinoxylan and pectin polysaccharides rich in rhamnose galacturonic acid polysaccharide type I (RG-I).

[0025] In step S2 of this invention, the lyophilized polysaccharide is reconstituted with water, dialyzed using a 3500 Da dialysis bag for 36–48 hours, and then precipitated with anhydrous ethanol in a volume 3–4 times that of the extract. The dialysis bag is used to retain polysaccharides with a molecular weight greater than 3500 Da, thus preserving polysaccharides with higher degrees of branching.

[0026] The application of the anti-aging rice starch prepared by the method described in this invention in food production or as a food anti-aging agent is also within the scope of protection of this invention.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The present invention uses the residue after extracting polysaccharides from barley tender leaf powder as raw material, and uses xylanase and cellulase for secondary extraction to obtain polysaccharides. The polysaccharides have the effect of delaying starch aging and improving the value of barley tender leaf by-products.

[0029] (2) The polysaccharide prepared by the present invention is mainly composed of arabinoxylan and pectin polysaccharide rich in rhamnogalacturonan type I (RG-I). Among them, arabinoxylan is a branched polymer, and RG-I is also highly branched. In the mixed system, the complex entanglement between arabinoxylan and pectin polysaccharide rich in RG-I forms a network structure, which can increase the steric hindrance between starch molecules, reduce the probability of the orderly rearrangement of starch molecules, thereby inhibiting starch aging. At the same time, the ability of the hydroxyl groups of the hulless barley young leaf residue polysaccharide to form hydrogen bonds with the hydroxyl groups of starch molecules is stronger than that between the hydroxyl groups of starch molecules, thus interfering with the formation of hydrogen bonds in the starch molecular microcrystalline bundle and further delaying starch aging.

[0030] (3) The anti-aging starch prepared by the present invention can be used to prepare various foods or directly used as an anti-aging agent, which is extremely important for food safety and dietary health. Brief Description of the Drawings

[0031] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects and advantages of the present invention will become more obvious:

[0032] Figure 1 The aging recovery values of different products. Detailed Embodiments

[0033] The present invention will be described in detail below with reference to specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that those of ordinary skill in the art can make several changes and improvements without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0034] The following examples and comparative examples relate to the method for measuring the aging recovery value. Specifically, the aging property of starch is characterized by the aging recovery value measured by RVA, and the measurement method is as follows: Weigh the sample (1.96 g, dry basis) into an aluminum tube equipped with a rapid viscosity analyzer, and then add deionized water to a total mass of 28 g to obtain a 7% starch suspension. Stir evenly to avoid sample agglomeration, and then connect the aluminum can to the rapid viscosity analyzer and run the analysis program. Each sample is repeated 3 times. The set program is as follows: The sample is first equilibrated at 50 °C for 1 min and stirred with a plastic paddle at 960 r / min for 10 s. Subsequently, the stirring speed is reduced to 160 r / min and maintained until the end of the test. Then, the set temperature starts from 50 °C and rises to 95 °C at a constant rate of 6 °C / min, and is maintained at 95 °C for 5 min. Subsequently, within 7.5 min, the temperature is reduced from 95 °C to 50 °C, and finally maintained at 50 °C for 2 min. After the reaction, the viscosity curve of the sample can be obtained, from which the aging recovery value can be analyzed.

[0035] Example 1

[0036] This invention discloses a method for preparing anti-aging wheat starch, comprising the following steps:

[0037] (1) Preparation of barley tender leaf residue: Barley tender leaves were mixed with water at a solid-liquid ratio of 1:30. 200U of heat-resistant α-amylase was added per gram of barley tender leaves to enzyme and the mixture was incubated at 80℃ for 1 hour. At the same time, 1500U of papain and 300U of saccharifying enzyme were added and the mixture was incubated at 65℃ for 2 hours for enzymatic hydrolysis. The mixture was cooled to room temperature and centrifuged to collect the residue.

[0038] (2) Preparation of polysaccharide from barley young leaf residue: The residue was mixed with water at a solid-liquid ratio of 1:30. After adjusting the pH to 5.0 with 0.561 mol / L hydrochloric acid, 700 U xylanase and 300 U cellulase were added per gram of residue to enzyme (the residue accounted for about 50% of the barley young leaves). The mixture was then incubated in a water bath at 55°C for 3 hours. After cooling to room temperature, the mixture was centrifuged. The supernatant was precipitated with 3 times the amount of 95% ethanol. The precipitate was reconstituted with water. Polysaccharides with a molecular weight cutoff greater than 3500 Da were retained by dialyzing. The mixture was concentrated by rotary evaporation and then freeze-dried under vacuum to obtain the polysaccharide from the barley young leaf residue.

[0039] (3) Preparation of anti-aging wheat starch: 5 parts of barley leaf residue polysaccharide were dissolved in 1500 parts of water to obtain a uniform polysaccharide solution. 95 parts of wheat starch were added to the polysaccharide solution and stirred to obtain a mixed system. The mixed system was heated at 95℃ for 15 min, cooled at room temperature for 12 h, and freeze-dried to obtain the finished product.

[0040] Implementation results: Figure 1 It can be seen that the aging recovery value of the product in Example 1 is 103 cP, which significantly improves the anti-aging ability of wheat starch compared with the aging recovery value (388 cP) of the control group (wheat starch).

[0041] Example 2

[0042] This embodiment relates to a method for preparing anti-aging wheat starch, the steps of which are as follows:

[0043] (1) Preparation of barley young leaf polysaccharide: Barley young leaves were mixed with water at a solid-liquid ratio of 1:30. After adjusting the pH to 5.0 with 0.561 mol / L hydrochloric acid, 700 U xylanase and 300 U cellulase were added according to the ratio of barley young leaves to enzymes. The mixture was then incubated in a water bath at 55°C for 3 hours. After cooling to room temperature, the mixture was centrifuged. The supernatant was precipitated with 3 times the amount of 95% ethanol. The precipitate was redissolved in water and dialyzed to retain polysaccharides with a molecular weight cutoff greater than 3500 Da. The polysaccharides were concentrated by rotary evaporation and then freeze-dried under vacuum to obtain barley young leaf polysaccharide.

[0044] (2) Preparation of anti-aging wheat starch: 5 parts of barley tender leaf polysaccharide were dissolved in 1500 parts of water to obtain a uniform polysaccharide solution. 95 parts of wheat starch were added to the polysaccharide solution and stirred to obtain a mixed system. The mixed system was heated at 95℃ for 15 min, cooled at room temperature for 12 h, and freeze-dried to obtain the finished product.

[0045] Implementation results: Figure 1 It can be seen that the aging recovery value of the product of Example 2 is 360 cP, which is significantly higher than that of Example 1, indicating that its anti-aging ability is lower than that of Example 1. Compared with the aging recovery value of the control group (wheat starch) (388 cP), the aging recovery value is smaller, indicating that Example 2 slightly improves the anti-aging ability of wheat starch.

[0046] Example 3

[0047] This embodiment relates to a method for preparing anti-aging wheat starch, which is the same as that in Embodiment 1, except that in the preparation of barley young leaf residue polysaccharide, after the precipitate is re-dissolved in water, it is not dialyzed, and the polysaccharide with a molecular weight greater than 3500 Da is not retained. Instead, it is directly concentrated by rotary evaporation and freeze-dried to obtain barley young leaf residue polysaccharide.

[0048] Implementation results: Figure 1 It can be seen that the aging recovery value of the product of Example 3 is 355 cP, which is significantly higher than that of Example 1, indicating that its anti-aging ability is lower than that of Example 1. Compared with the aging recovery value of the control group (wheat starch) (388 cP), the aging recovery value is smaller, indicating that Example 3 slightly improves the anti-aging ability of wheat starch.

[0049] Example 4

[0050] This embodiment relates to a method for preparing anti-aging wheat starch, which is the same as in Example 1, except that in the preparation of barley young leaf residue polysaccharide, the residue is mixed with water at a solid-liquid ratio of 1:30, the pH is adjusted to 5.0 with 0.561 mol / L hydrochloric acid, 700 U xylanase is added according to the ratio of residue to enzyme, and the mixture is heated in a water bath at 55°C for 3 hours. After cooling to room temperature, the mixture is centrifuged, and the supernatant is precipitated with 3 times the amount of 95% ethanol. After the precipitate is reconstituted with water, the polysaccharide with a molecular weight cutoff greater than 3500 Da is dialyzed, concentrated by rotary evaporation, and then freeze-dried under vacuum to obtain barley young leaf residue polysaccharide.

[0051] Implementation results: Figure 1 It can be seen that the aging recovery value of the product of Example 4 is 283 cP, which is lower than the aging recovery value of the control group (wheat starch) (388 cP), indicating that Example 4 has improved the anti-aging ability of wheat starch to a certain extent; however, the aging recovery value is significantly higher than that of Example 1, indicating that its anti-aging ability is lower than that of Example 1.

[0052] In this embodiment, the yield is optimal when the amount of xylanase is 700-800 U / g. When the amount of xylanase is further increased, the yield of soluble polysaccharides will decrease. This is because when xylanase is excessive, soluble polysaccharides are degraded into small molecule sugars. These small molecule sugars cannot be precipitated during alcohol precipitation or are not retained during dialysis, thus leading to a decrease in yield.

[0053] Example 5

[0054] This embodiment relates to a method for preparing anti-aging wheat starch, which is the same as in Example 1, except that in the preparation of barley young leaf residue polysaccharide, after adjusting the pH to 5.0 with 0.561 mol / L hydrochloric acid, 300 U of cellulase is added according to the ratio of residue to enzyme, and the mixture is heated in a water bath at 55°C for 3 hours. After cooling to room temperature, the mixture is centrifuged, and the supernatant is precipitated with 3 times the amount of 95% ethanol. After redissolving the precipitate in water, the polysaccharide with a molecular weight cutoff greater than 3500 Da is retained by dialyzing. After rotary evaporation and concentration, the mixture is freeze-dried under vacuum to obtain barley young leaf residue polysaccharide.

[0055] Implementation results: Figure 1 It can be seen that the aging recovery value of the product of Example 5 is 257 cP, which is lower than the aging recovery value of the control group (wheat starch) (388 cP), indicating that Example 5 has improved the anti-aging ability of wheat starch to a certain extent; however, the aging recovery value is significantly higher than that of Example 1, indicating that its anti-aging ability is lower than that of Example 1.

[0056] In this embodiment, the yield is optimal when the amount of cellulase is 300-400 U / g. When the amount of cellulase is further increased, the enzymatic hydrolysis is excessive, and more polysaccharides are converted into small molecule oligosaccharides. These oligosaccharides cannot be precipitated during alcohol precipitation or cannot be retained during dialysis, resulting in a lower yield and failure to exert a good anti-aging effect.

[0057] Example 6

[0058] This embodiment relates to a method for preparing anti-aging wheat starch. The method is the same as that in Embodiment 1, except that: in the preparation of anti-aging wheat starch, 5 parts of barley tender leaf residue polysaccharide are dissolved in 1500 parts of water to obtain a uniform polysaccharide solution. 95 parts of wheat starch are added to the polysaccharide solution, stirred and mixed to obtain a mixed system. No heating is performed. After centrifugation, the product is freeze-dried to obtain the finished product.

[0059] Implementation results: Figure 1 It can be seen that the aging recovery value of the product of Example 6 is 379 cP, which is not significantly different from the aging recovery value (388 cP) of the control group (wheat starch). This indicates that Example 6 did not improve the anti-aging ability of wheat starch.

[0060] Comparative Example 1

[0061] This embodiment relates to a method for preparing anti-aging wheat starch, which is basically the same as that in Embodiment 1, except for the preparation of barley leaf polysaccharides. The steps are as follows: Barley tender leaves are mixed with water at a solid-liquid ratio of 1:30. Based on the ratio of barley tender leaves to enzymes, 200U of heat-resistant α-amylase is added and the mixture is incubated at 80℃ for 1 hour. Simultaneously, 1500U of papain and 300U of glucoamylase are added and incubated at 65℃ for 2 hours for enzymatic hydrolysis. After cooling to room temperature, the pH is adjusted to 5.0 with 0.561mol / L hydrochloric acid. Then, based on the ratio of barley tender leaves to enzymes, 1400U of xylanase and 600U of cellulase are added and incubated at 55℃ for 3 hours. After cooling to room temperature, the mixture is centrifuged. The supernatant is precipitated with three times the volume of 95% ethanol. The precipitate is reconstituted with water, dialyzed to retain polysaccharides with a molecular weight cutoff greater than 3500 Da, concentrated by rotary evaporation, and then freeze-dried under vacuum to obtain barley tender leaf polysaccharides.

[0062] Implementation results: Figure 1 It can be seen that the aging recovery value of the product of Comparative Example 1 is 361 cP, which is significantly higher than that of Example 1, indicating that its anti-aging ability is lower than that of Example 1. Compared with the aging recovery value of the control group (wheat starch) (388 cP), the aging recovery value is smaller, indicating that Comparative Example 1 slightly improves the anti-aging ability of wheat starch. The reason is that the barley leaf polysaccharide obtained in this comparative example is mainly oligosaccharide, such as xylooligosaccharide, glucose, and water-soluble β-glucan. With low molecular weight, it cannot form a complex network structure to inhibit starch molecule rearrangement, so the effect on starch aging is not significant.

[0063] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for preparing anti-aging wheat starch, characterized in that, Includes the following steps: S1. Young barley leaves are enzymatically hydrolyzed using heat-resistant α-amylase, papain, and saccharifying enzyme. After solid-liquid separation, the residue is collected. The residue is mixed with water, and xylanase and cellulase are added at pH 5.0-5.

5. Enzymatic hydrolysis is carried out in a water bath at 50-55℃ for 3-4 hours. After cooling to room temperature, centrifugation is performed. After solid-liquid separation, the polysaccharides in the solution are precipitated with ethanol. The precipitate is redissolved, dialyzed, concentrated by rotary evaporation, and then freeze-dried under vacuum to obtain the polysaccharides. The enzyme dosage per gram of residue is: 700-800 U xylanase and 300-400 U cellulase. The dialysis retains polysaccharides with a molecular weight greater than 3500 Da. S2. Dissolve the polysaccharide in water to obtain a polysaccharide solution. Add starch to the polysaccharide solution and stir to obtain a mixed system. Heat the mixed system to gelatinize it, cool it at room temperature, and freeze-dry it to obtain the finished product.

2. The preparation method according to claim 1, characterized in that, In step S1, barley tender leaves are mixed with water at a solid-liquid ratio of 1:30~40 and then enzymatically hydrolyzed; the enzyme dosage per gram of barley tender leaves is: 200~250U of thermostable α-amylase, 1000~1500U of papain, and 250~300U of saccharifying enzyme.

3. The preparation method according to claim 1, characterized in that, In step S1, the thermoresistant α-amylase is first used for hydrolysis in a water bath at 70-80℃ for 1-2 hours; then papain and saccharifying enzyme are added and hydrolyzed in a water bath at 55-65℃ for 2-3 hours. After cooling to room temperature, the mixture is centrifuged.

4. The preparation method according to claim 1, characterized in that, In step S1, the residue is mixed with water at a solid-liquid ratio of 1:25~30.

5. The preparation method according to claim 1, characterized in that, In step S1, the supernatant obtained after enzymatic hydrolysis and centrifugation of the residue is precipitated with 3-4 times the amount of 95% ethanol.

6. The preparation method according to claim 1, characterized in that, In step S1, the solution is rotary evaporated at 50~60℃ for 0.5~1h, and the concentrate is freeze-dried under vacuum at -40~-50℃ for 12~24h.

7. The preparation method according to claim 1, characterized in that, In step S2, 1 to 5 parts of the polysaccharide are dissolved in 1000 to 1500 parts of water to obtain a polysaccharide solution.

8. The preparation method according to claim 1, characterized in that, In step S2, wheat starch is added to the polysaccharide solution according to a mass ratio of polysaccharide to wheat starch of 1~5:95~99; the heating and gelatinization is carried out at 90~95℃ for 15~20 min.

9. The use of an anti-aging wheat starch prepared by any one of claims 1-8 in the production of food or as a food anti-aging agent.

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