A digestible barley starch based on ultrasound-induced structural remodeling, its preparation method and application

Abstract

This invention discloses a digestible barley starch based on ultrasound-induced structural reorganization, its preparation method, and its applications, belonging to the field of modified starch processing technology. This invention employs a power-controllable ultrasound-induced starch structural reorganization process. By precisely controlling the ultrasonic input energy, a mechanical annealing effect is triggered in barley starch molecules at a critical ultrasonic power, simultaneously achieving multi-level ordered reconstruction of starch molecular chains and particle aggregates, significantly improving its digestibility and processing rheological properties.

Description

Technical Field

[0001] This invention relates to the field of modified starch processing technology, and in particular to a digestible highland barley starch based on ultrasound-induced structural recombination, its preparation method, and its application. Background Technology

[0002] Barley, scientifically known as naked barley, is a crop belonging to the genus *Hordeum* of the Poaceae family. It belongs to the same cereal grains as wheat, oats, and buckwheat. As a naked barley variety unique to the Qinghai-Tibet Plateau, barley is characterized by high protein, high fiber, high vitamins, and low glycemic index. Barley starch, the most abundant component (47.90%-79.0%), is the core factor determining barley's processing characteristics, nutritional quality, and functional expansion. Although barley itself has strong digestibility, the digestibility of processed barley starch can reach over 90% after 180 minutes of digestion. This difference mainly stems from the multi-scale structure of barley starch. Currently, domestic and international research on barley starch primarily focuses on the effects of functional factors, with little attention paid to the influence of changes in the starch's own structure on its functional properties.

[0003] Currently, the basic modification methods for natural starch mainly fall into three categories: physical modification, chemical modification, and enzymatic modification. Both chemical and enzymatic modifications require the introduction of additional substances into the starch system, while physical modification technology, considering safety, environmental friendliness, and cost-effectiveness, has high potential for starch modification. Physical modification is further divided into conventional heat treatment modification and novel non-heat treatment modification processes. Patent CN201710083625.2 discloses a method for adjusting the digestibility of highland barley starch through fluidized bed combined with alkaline spray heat treatment. While this method can effectively increase the content of resistant starch, it involves the use of chemical reagents (alkaline solution) and high-temperature (100-180℃) treatment, resulting in potential chemical residues, high energy consumption, and the possibility of inducing non-targeted thermal degradation of starch. Patent application CN119432952A discloses a method for preparing low-GI corn starch through dual enzymatic hydrolysis, which increases the resistant starch content by adding branching enzymes twice. While this enzymatic method can effectively reduce starch digestibility, it suffers from drawbacks such as cumbersome process steps, the need for precise pH and temperature control, multiple alcohol and water washings after enzymatic hydrolysis leading to high solvent consumption, high starch loss rate, and high production costs. Furthermore, common acid debranching methods pose equipment corrosion and safety issues, while single physical modification (such as wet heat or extrusion) or physical-enzymatic synergistic processes often face challenges such as unstable processing efficiency, limited functional enhancement, or complex processes.

[0004] Therefore, developing a green, efficient, and simple physical modification method that can regulate the multi-scale structure of starch is crucial for improving the nutritional function and processing quality of highland barley starch. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a digestible barley starch based on ultrasound-induced structural reorganization, its preparation method, and its application. The invention employs a power-controllable ultrasound-induced starch structural reorganization process. By precisely controlling the ultrasonic input energy, mechanical annealing effects are triggered in barley starch molecules at critical ultrasonic power, which can simultaneously achieve multi-level ordered reconstruction of starch molecular chains and particle aggregates, significantly improving its digestibility and processing rheological properties.

[0006] To achieve the above objectives, this invention provides a method for preparing digestible barley starch based on ultrasound-induced structural recombination, comprising the following steps: S1. Wash the barley and soak it in water for the first time to obtain swollen barley; soak the swollen barley for the second time, grind it for the first time, pass the grinding slurry through a 100-mesh sieve, and centrifuge it for the first time to obtain the precipitate after centrifugation; mix the precipitate after centrifugation with ethanol, stir, centrifuge it for the second time, dry it, grind it for the second time, and pass it through a 100-mesh sieve to obtain barley starch. S2. Mix and stir barley starch with water to obtain a suspension; treat the suspension with ultrasound, centrifuge, dry, grind and pass through a 100-mesh sieve to obtain digestible barley starch based on ultrasound-induced structural recombination.

[0007] Preferably, in S1, the mass ratio of barley to water is 1:8, the temperature of the first soaking is 4°C, and the soaking time is 12h; the second soaking process is as follows: the swollen barley is added to a 0.1g / mL sodium hydroxide solution and soaked for 3h, and the sodium hydroxide solution is replaced every 1h.

[0008] Preferably, in S1, the first grinding medium is a 0.02 g / mL sodium hydroxide solution, and the temperature of the 0.02 g / mL sodium hydroxide solution is 4°C; the first grinding speed is 3000 rpm, and the first grinding time is 2 min; the first centrifugation speed is 5000 rpm, and the first centrifugation time is 15 min.

[0009] Preferably, in S1, the volume fraction of ethanol is 80%, the stirring temperature is 25°C, the stirring time is 2 hours, the drying temperature is 45°C, and the drying time is 12 hours.

[0010] Preferably, in S2, the mass-to-volume ratio of barley starch to water is 3g:12mL, the stirring speed is 950rpm, the stirring temperature is 18-25℃, and the stirring time is 5min.

[0011] Preferably, in S2, the ultrasonic treatment power is 400-500W, the ultrasonic treatment time is 30min, the ultrasonic treatment frequency is 25kHz, the ultrasonic treatment mode is a pulse mode with 2s on and 2s off, the ultrasonic treatment temperature is 20-25℃, and the ultrasonic treatment probe is immersed in the suspension surface to a depth of 2cm.

[0012] Preferably, in S2, the centrifugation speed is 5000 rpm, the centrifugation time is 15 min, the drying temperature is 45℃, and the drying time is 12 h.

[0013] The present invention also provides a digestible barley starch based on ultrasound-induced structural recombination, which is prepared by the above-described preparation method.

[0014] The present invention also provides an application of the resistant barley starch based on ultrasound-induced structural recombination, which is used to process low glycemic index foods and resistant starch-based foods.

[0015] The present invention also provides an application of the resistant barley starch based on ultrasound-induced structural recombination, which is used to prepare healthy gel-type foods.

[0016] Therefore, the present invention, employing the above-mentioned method for preparing and applying an ultrasound-induced structural recombination-based digestible barley starch, has the following beneficial effects: (1) The present invention adopts a power controllable ultrasound-induced starch structure recombination process. By precisely controlling the ultrasonic input energy, the mechanical annealing effect of barley starch molecules is triggered under the critical ultrasonic power, which can simultaneously realize the multi-level orderly reconstruction of starch molecular chains and particle aggregation state, and fundamentally regulate the microstructure of starch.

[0017] (2) In view of the problem that barley starch has insufficient resistance to digestion and difficulty in synergistically improving processing performance and nutritional function when it is used as a staple food raw material, the present invention significantly improves the resistant starch (RS) content of barley starch through ultrasonic-induced molecular recombination process, and synergistically enhances its gel strength and thermal stability. This makes the final product have excellent processing adaptability and rheological properties while having the potential to generate low glycemic index.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0019] Figure 1 This is a comparison chart of the storage modulus of digestible highland barley starch based on ultrasound-induced structural recombination in Examples 1-2 of the present invention and highland barley starch in Comparative Examples 1-4. Figure 2This is a comparison chart of the loss modulus of the digestible highland barley starch based on ultrasound-induced structural recombination in Examples 1-2 of the present invention and the highland barley starch in Comparative Examples 1-4. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parameters.

[0022] In this invention, highland barley was purchased from Golmud Namulan Agricultural Development Co., Ltd.; Aspergillus niger amylolucosidase and porcine pancreatic α-amylase were purchased from Maclean Biochemical Co., Ltd.; and the glucose content assay kit was purchased from Lanjieke Technology Co., Ltd.

[0023] Example 1 A method for preparing digestible highland barley starch based on ultrasound-induced structural recombination includes the following steps: S1. Wash 100g of highland barley three times with ultrapure water to remove surface dust and residual bran. Then, soak it in 800mL of ultrapure water at 4℃ for 12 hours to obtain swollen highland barley. Next, soak it in 0.1g / mL NaOH solution for 3 hours, changing the NaOH solution every hour during this period. Then, replace the 0.1g / mL NaOH solution with a 0.02g / mL sodium hydroxide solution pre-cooled to 4℃ and pour it into a blender at 300... Grind at 0 rpm for 2 minutes. After passing the grinding slurry through a 100-mesh sieve, centrifuge at 5000 rpm for 15 minutes. Scrape off the brownish-yellow substance on the surface. Repeat centrifugation with ultrapure water until the brownish-yellow substance is completely removed. Add 80% ethanol (volume fraction) to the precipitate after centrifugation and stir at 25°C for 2 hours. Then centrifuge to remove the ethanol. Add water and repeat centrifugation three times. The resulting white precipitate is dried in an oven at 45°C for 12 hours. Grind until it passes through a 100-mesh sieve to obtain barley starch. S2. Take 3g of highland barley starch and add it to a centrifuge tube containing 12mL of ultrapure water. Stir at 950rpm for 5min at 25℃ to obtain a suspension. The suspension was placed in an ice-water bath to maintain the temperature of the system between 20-25℃. Ultrasonic treatment was performed using an ultrasonic cell disruptor. The ultrasonic conditions were: frequency 25kHz, time 30min, power 400W, and a pulse mode of 2s on and 2s off throughout the process. The probe was immersed to a depth of 2cm in the suspension. After ultrasonic treatment, the product was centrifuged at 5000 rpm for 15 min, dried in an oven at 45℃ for 12 h, and then ground through a 100-mesh sieve to obtain digestible highland barley starch based on ultrasonic-induced structural recombination.

[0024] Example 2 This embodiment operates the same as Embodiment 1, except that in S2, the power of the ultrasonic treatment is 500W.

[0025] Comparative Example 1 This comparative example operates in the same way as Example 1, except that S2 is not performed.

[0026] Comparative Example 2 This embodiment operates the same as Embodiment 1, except that in S2, the power of the ultrasonic treatment is 200W.

[0027] Comparative Example 3 This embodiment operates the same as Embodiment 1, except that in S2, the power of the ultrasonic treatment is 300W.

[0028] Comparative Example 4 This embodiment operates the same as Embodiment 1, except that in S2, the power of the ultrasonic treatment is 600W.

[0029] The in vitro digestibility of the ultrasound-induced structurally recombinant barley starch from Examples 1-2 and the barley starch from Comparative Examples 1-4 was determined: The sample (0.2 g) was mixed with 4 mL of water and 6 mL of sodium acetate buffer (0.2 M, pH = 5.2), and stirred in a water bath at 95°C for 20 min to completely gelatinize the sample; then 10 mL of preheated mixed enzyme solution (porcine pancreatic α-amylase 300 U / mL and Aspergillus niger amylolucosidase 60 U / mL) was added, and the mixture was stirred in a water bath at 37°C at 0, 10, and 20... Equal volumes of digestion solution (0.1 mL) were collected at time intervals of 30, 60, 90, 120, and 180 min, and immediately mixed with 1.9 mL of anhydrous ethanol to terminate enzyme activity. The mixture was then centrifuged at 8000 rpm for 10 min, and the supernatant was collected for subsequent analysis. Glucose content was determined using a glucose oxidase peroxidase kit (GOPOD method), and starch hydrolysis rate, rapidly digestible starch content (RDS), slowly digestible starch content (SDS), and resistant starch content (RS) were calculated using the following formulas: Among them, G 20 and G120 These represent the glucose content released after 20 min and 120 min of starch digestion, respectively; TS is the total starch content of the sample, and the conversion factor from glucose to starch is 0.9.

[0030] Based on the first-order kinetic equations of motion, the digestion rates of all starch samples were fitted using logarithmic slope (LOS) analysis combined with modified nonlinear least squares (NLLS): Where C t This represents the starch digestibility at a specific time point (t), where C0 is the initial digestibility, and C... ∞ This represents the estimated digestibility of starch after each reaction, where k is the starch digestion rate coefficient.

[0031] The results are shown in Tables 1 and 2. The lowercase letters (af) in the tables indicate that the effect of ultrasound power on the in vitro digestibility of barley starch is significant.

[0032] Table 1. Results of in vitro digestibility determination for Comparative Examples 1-3

[0033] Table 2. Results of in vitro digestibility determination for Examples 1-2 and Comparative Example 4

[0034] As shown in Table 1, after ultrasonic treatment with 200W (Comparative Example 2) and 300W (Comparative Example 3), the content of rapidly digestible starch (RDS) in the samples increased from 63.59% to 68.15% and 71.01%, respectively, while the content of slowly digestible starch (SDS) and resistant starch (RS) decreased. The fitted final digestibility (C) was consistent with the results. ∞ The content of RDS increased from 91.34% to 96.65%. This indicates that low-power ultrasonic cavitation can disrupt the surface structure of starch granules, thereby increasing the accessibility of digestive enzymes to starch substrates and promoting hydrolysis. However, when the ultrasonic power was increased to 400W (Example 1) and 500W (Example 2), the content of RDS showed a brief downward trend, while the content of RS increased. When the power was further increased to 600W (Comparative Example 4), the intense cavitation effect caused significant damage to the surface barrier of starch granules, and the internal starch molecular chains broke down. The short chains maximized the accessibility of digestive enzymes, thus the RDS content increased to 77.98%. ∞The fitting results exceeded 100%, while the RS content decreased to a minimum of 4.49%. The rapid digestion rate constant (k1) generally increased with increasing ultrasonic power, indicating that ultrasonic treatment generally accelerated the hydrolysis of easily digestible starch in the early stages of digestion; however, the slow digestion rate constant (k2) showed the opposite trend, generally decreasing with increasing power. At ultrasonic powers of 400W and 500W, the starch components that were not rapidly hydrolyzed consisted of a more ordered and dense structure, making them more difficult to digest, hence the lower k2 values.

[0035] The long-range and short-range ordered structures of the ultrasound-induced structural reorganization-based resistant barley starch from Examples 1-2 and the barley starch from Comparative Examples 1-4 were determined: Determination of long-range ordered structure: The crystal structure inside starch sample granules was determined using an X-ray scattering instrument. To ensure the accuracy and reliability of the results, barley starch powder that had passed through a 200-mesh sieve was dried in an oven at 45°C for 24 hours. Under the conditions of accelerating voltage of 35kV, current of 25mA, and step size of 0.02°, the 2θ range within the range of 5°-40° was measured at a scanning speed of 2° / min, and the crystallinity of the sample was calculated using software fitting.

[0036] Determination of short-range ordered structure: Infrared spectra of each starch sample were obtained using the potassium bromide pellet method and Fourier transform infrared spectroscopy. The double helixity (short-range order) of the samples was evaluated using PeakFit v 4.12. The test conditions were as follows: wavenumber range 4000-400 cm⁻¹. -1 The resolution is 4cm. -1 The scan was performed 64 times. Analysis software was used to analyze samples from 1200-800 cm... -1 The infrared spectrum within the range was deconvolved and the 1047 cm⁻¹ was calculated. -1 / 1022cm -1 995cm -1 / 1022cm -1 The ratios are denoted as R1047 / 1022 and R1022 / 995, respectively.

[0037] The results are shown in Table 3.

[0038] Table 3. Results of Long-Range Orderliness and Short-Range Orderliness Measurement

[0039] As can be seen from Table 3: (1) The crystallinity of natural barley starch (Comparative Example 1) was 32.04%. At an ultrasonic power of 200W (Comparative Example 2), the crystallinity of the sample decreased, but the change was not significant. With increasing ultrasonic power, the overall crystallinity showed a decreasing trend, and at an ultrasonic power of 600W (Comparative Example 4), the crystallinity of barley starch decreased to 23.17%. With increasing ultrasonic power to 300W (Comparative Example 3) and 400W (Example 1), the increased energy and water swelling promoted the expansion of amorphous regions within the starch and the destruction of a small portion of the ordered structure, thus resulting in a decrease in crystallinity. Furthermore, the crystallinity at an ultrasonic power of 500W (Example 2) was higher than that at 400W (28.12%). This may be attributed to the temporary offsetting of the destruction of crystalline regions by structural reorganization and the formation of ordered structures, leading to a rebound in crystallinity. However, when the ultrasonic power was further increased to 600W, destruction became dominant, resulting in a significant decrease in crystallinity.

[0040] (2) The R1047 / 1022 and R1022 / 995 values ​​of natural highland barley starch (Comparative Example 1) were 0.84 and 1.03, respectively. At 200W ultrasonic power, the R1047 / 1022 and R1022 / 995 values ​​were 0.85 and 1.01, respectively, indicating that 200W ultrasonic power has a slight effect on the structure of highland barley starch, with limited impact on the internal crystalline structure. With increasing ultrasonic power (200-400W), the R1047 / 1022 value increased. This is because ultrasound improves the interaction between starch molecular chains, promoting molecular rearrangement and the formation of an ordered structure. However, at the same time, the R1022 / 995 value decreased. This may be attributed to the fact that ultrasound causes water molecules to penetrate into the highland barley starch granules, and the swelling of the amorphous regions due to water absorption disrupts the conformation of the starch molecular chains, increasing the disorder of the chains. In addition, it was observed that at an ultrasonic power of 500W, the R1047 / 1022 value further increased to 0.904, and the R1022 / 995 value also improved. This is likely because sufficient ultrasonic energy makes the movement and entanglement of molecular chains more significant, improving not only the orderliness of the double helix but also the compactness of the double helix arrangement. However, excessive ultrasonic energy can damage the double helix structure and molecular chains inside the barley starch granules, leading to a decrease in the R1047 / 1022 and R1022 / 995 values ​​of barley starch at an ultrasonic power of 600W.

[0041] The rheological and thermal properties of the ultrasonically induced structural remodeling resistant barley starch from Examples 1-2 and the barley starch from Comparative Examples 1-4 were measured: Rheological property determination: The starch sample to be tested was mixed with water to obtain a starch suspension with a concentration of 5 g / mL. The suspension was stirred in a 95℃ water bath for 30 min. After cooling to room temperature and holding for 30 min, the rheological properties of the starch paste were determined using a modular rotational rheometer. A P35 rotor was selected, with a gap of 1 mm, a strain amplitude of 1%, and a temperature of 25℃. The storage modulus and loss modulus in the frequency range of 0.1-10 Hz were tested.

[0042] Thermal properties determination: The thermal properties of starch were determined using a differential scanning calorimeter. 3 mg of the starch sample and 6 µL of water were added to an aluminum liquid crucible, sealed, and allowed to equilibrate at room temperature for 24 h. An empty aluminum liquid crucible was used as a control. The programmed heating rate was set to 10 °C / min, and data were collected within the range of 20–100 °C.

[0043] The results of the rheological property measurements are as follows: Figure 1 , Figure 2 As shown in Table 4, the results of the thermal property measurements are as follows.

[0044] Table 4 Results of thermal property determination

[0045] from Figure 1 and Figure 2 As can be seen, within the 0.1-10Hz range, the G′ and G′′ values ​​of all samples increased significantly with increasing frequency, and G′ was always higher than G′′, indicating that all starch pastes exhibited typical, elastic-dominant, weak gel systems. However, the G′ and G′′ values ​​of ultrasonically modified starch were higher than those of natural barley starch, showing a clear power dependence. This is because the structural disruption caused by ultrasound and the association of polymer chains during cooling formed a viscoelastic network. Samples ultrasonicated at 400W and 500W showed higher gel strength, indicating the formation of a more ordered and compact three-dimensional network structure. Furthermore, barley starch under 300W ultrasonic power was in a transitional period between disruption and remodeling; at this point, ultrasound promoted the rupture of barley starch granules, increased the permeability of the granules, and thus improved the rheological properties of the starch paste. Although the high solubility of barley starch under 600W ultrasonic power is high due to structural damage, its numerous short chains can still form a physical gel of a certain strength through entanglement when cooled. Therefore, its G′ is still higher than that of 200W barley starch that has only undergone surface erosion and the original barley starch with unoptimized network.

[0046] As can be seen from Table 3, the peak gelatinization temperature (T) p ), final temperature (T) cBoth the enthalpy change of gelatinization (ΔH) and the enthalpy change of gelatinization showed significant and non-monotonic changes dependent on ultrasonic power. This indicates that ultrasonic treatment has little effect on the melting initiation temperature of unstable crystalline regions of barley starch, but has a more significant effect on the thermal properties of components with higher structural stability. Ultrasonic treatment significantly affected the enthalpy change of gelatinization (ΔH), and the ΔH value showed a non-monotonic trend with ultrasonic power. Compared with natural barley starch (9.77 J / g), low-power ultrasonic treatment (200 W and 300 W) gradually reduced the ΔH value to 8.05 J / g. This is mainly attributed to the ultrasonic cavitation effect and the mechanical action of shear force on starch granules, which weakens the amorphous structure and reduces the molecular order, thereby reducing the heat energy required for gelatinization of barley starch. Notably, the ΔH value of barley starch increased to 11.69 J / g at 500 W ultrasonic power, significantly higher than all other samples. This indicates that at 400 W ultrasonic power, the internal structure of starch granules began to rearrange. The process reaches its peak at 500W power, at which point the structure formed by the amorphous and crystalline regions is more stable than that of natural barley starch.

[0047] Therefore, the present invention adopts the above-mentioned digestible barley starch based on ultrasound-induced structural recombination, its preparation method and application. It adopts a power-controllable ultrasound-induced starch structural recombination process. By precisely controlling the ultrasound input energy, the mechanical annealing effect of barley starch molecules is triggered at the critical ultrasound power. This can simultaneously realize the multi-level orderly reconstruction of starch molecular chains and particle aggregation states, significantly improving its digestibility and processing rheological properties.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing digestible highland barley starch based on ultrasound-induced structural recombination, characterized in that: Includes the following steps: S1. Wash the barley and soak it in water for the first time to obtain swollen barley; soak the swollen barley for the second time, grind it for the first time, pass the grinding slurry through a 100-mesh sieve, and centrifuge it for the first time to obtain the precipitate after centrifugation; The precipitate after centrifugation was mixed with ethanol, stirred, centrifuged a second time, dried, ground a second time, and passed through a 100-mesh sieve to obtain barley starch. S2. Mix and stir barley starch with water to obtain a suspension; treat the suspension with ultrasound, centrifuge, dry, grind and pass through a 100-mesh sieve to obtain digestible barley starch based on ultrasound-induced structural recombination.

2. The method for preparing digestible highland barley starch based on ultrasound-induced structural recombination according to claim 1, characterized in that: In S1, the mass ratio of barley to water is 1:

8. The temperature of the first soaking is 4℃ and the soaking time is 12h. The second soaking process is as follows: the swollen barley is added to a 0.1g / mL sodium hydroxide solution and soaked for 3h, with the sodium hydroxide solution being replaced every 1h.

3. The method for preparing digestible highland barley starch based on ultrasound-induced structural recombination according to claim 1, characterized in that: In S1, the first grinding medium is a 0.02 g / mL sodium hydroxide solution, and the temperature of the 0.02 g / mL sodium hydroxide solution is 4 °C; the first grinding speed is 3000 rpm, and the first grinding time is 2 min; the first centrifugation speed is 5000 rpm, and the first centrifugation time is 15 min.

4. The method for preparing digestible highland barley starch based on ultrasound-induced structural recombination according to claim 1, characterized in that: In S1, the volume fraction of ethanol is 80%, the stirring temperature is 25℃, the stirring time is 2h, the drying temperature is 45℃, and the drying time is 12h.

5. The method for preparing digestible highland barley starch based on ultrasound-induced structural recombination according to claim 1, characterized in that: In S2, the mass-to-volume ratio of barley starch to water is 3g:12mL, the stirring speed is 950rpm, the stirring temperature is 18-25℃, and the stirring time is 5min.

6. The method for preparing digestible highland barley starch based on ultrasound-induced structural recombination according to claim 1, characterized in that: In S2, the ultrasonic treatment power is 400-500W, the ultrasonic treatment time is 30min, the ultrasonic treatment frequency is 25kHz, the ultrasonic treatment mode is a pulse mode with 2s on and 2s off, the ultrasonic treatment temperature is 20-25℃, and the ultrasonic treatment probe is immersed to a depth of 2cm in the suspension.

7. The method for preparing digestible highland barley starch based on ultrasound-induced structural recombination according to claim 1, characterized in that: In S2, the centrifugation speed is 5000 rpm, the centrifugation time is 15 min, the drying temperature is 45℃, and the drying time is 12 h.

8. A digestible barley starch based on ultrasound-induced structural recombination, characterized in that: It was prepared using the method for preparing resistant barley starch based on ultrasound-induced structural recombination as described in any one of claims 1-7.

9. An application of a digestible barley starch based on ultrasound-induced structural recombination, characterized in that: The resistant barley starch based on ultrasound-induced structural recombination described in claim 8 can be used to process low glycemic index foods and resistant starch-based foods.

10. An application of a digestible barley starch based on ultrasound-induced structural recombination, characterized in that: The digestible highland barley starch based on ultrasound-induced structural recombination as described in claim 8 is used to prepare healthy gel-type foods.

Images