Preparation method of oat grain powder capable of improving reconstituability and reducing GI

Abstract

The invention belongs to the technical field of deep processing of cereals, and discloses a preparation method of oat cereal flour capable of improving reconstituability and reducing GI (Growth Index), which comprises the following steps: dispersing cured oat flour according to a material-liquid ratio of 1: 4, adjusting the pH value to 4.8, adding a mixture of which the total enzyme activity is 2.5-7.5 U / g at 50 DEG C, carrying out enzymolysis for 6 hours, centrifuging, washing and drying to obtain enzymolysis oat flour, and drying to obtain the oat cereal flour capable of improving reconstituability and reducing GI (Growth Index). And mixing the enzymolysis oat flour with a citric acid solution, balancing at room temperature, drying, heating, washing and drying to obtain the modified oat flour. The fourier infrared spectrum of the oat powder treated by the method disclosed by the invention has a remarkable ester bond characteristic peak at 1744 cm <-1 >, which proves that citric acid and starch are successfully esterified and cross-linked. The water binding capacity of the product is remarkably improved, and the hydration and dispersity during brewing are effectively improved; the brewing caking rate is obviously reduced, and the instant solubility and the brewing quality are improved; meanwhile, an in-vitro digestion simulation experiment shows that the estimated glycemic index of the modified oat powder is remarkably reduced, and the modified oat powder has the characteristic of slow digestion.

Description

Technical Field

[0001] This application relates to the field of grain deep processing technology, specifically to a method for preparing oat cereal powder that improves reconstitution properties and reduces GI. Background Technology

[0002] Oats (Avenasativa L.) are rich in protein, dietary fiber, bioactive polyphenols, and flavonoids, earning them the title of "whole grain." With the increasing demand for healthy consumption, whole grain meal replacement powders, represented by oats, are widely popular due to their convenience. However, technological bottlenecks restrict the further development of this industry: on the one hand, oat powder is prone to clumping when brewed, severely impacting the sensory experience; on the other hand, traditional processing results in a high glycemic index (GI), which does not align with the health trend of slow digestion and low burden. Furthermore, oats face challenges in processing well in beverages and instant cereal products due to their poor adaptability and rapid digestion. Therefore, developing a method for preparing oat cereal powder that combines high reconstitution properties with a low GI is of significant value in broadening the application scenarios of oats and promoting industrial upgrading. Summary of the Invention

[0003] This invention addresses the shortcomings of existing instant oat flour technologies, such as clumping during preparation, high glycemic index (GI), and limited application. It provides a processing method for oat flour using enzymatic hydrolysis and citric acid modification, significantly improving its dispersibility and digestibility. Based on enzymatic hydrolysis and citric acid modification technologies, this invention enhances the hydration capacity of oat starch granules through specific enzyme treatment, allowing for more even water distribution and promoting uniform and complete swelling of the oat flour, effectively reducing clumping. Citric acid induces cross-linking and rearrangement of starch molecules, increasing resistant starch content and reducing enzyme accessibility, thereby effectively lowering the product's GI value. This method is simple to operate, provides stable modification effects, and yields a product with good reconstitution properties and a slow digestion rate, suitable for meal replacements and consumption by special populations such as diabetics. It possesses significant advantages for industrial production and has broad market application prospects.

[0004] The above-mentioned objective of this invention is achieved through the following technical solutions: On the one hand, a method for preparing oat cereal flour that improves its reconstitution properties and reduces its glycemic index (GI) is proposed, including the following steps: (1) Disperse cooked oat flour in pure water at a ratio of 1:4, adjust the pH to 4.8, and magnetically stir in a 50℃ water bath for 10 min. Add a mixed enzyme with a total enzyme activity of 2.5-7.5 U / g and enzymatically hydrolyze at 50℃ and 150 rpm for 6 h. After the enzymatic hydrolysis is completed, add 12.5% ​​anhydrous ethanol of the enzymatic hydrolysate volume to terminate the reaction. Centrifuge the enzymatic hydrolysate, collect the precipitate, wash, dry, and pulverize to obtain enzymatically hydrolyzed oat flour. (2) Mix the enzymatically hydrolyzed oat flour with a citric acid solution with a concentration of 0.01-0.05 g / mL, magnetically stir, spread the mixture on a tray, equilibrate at room temperature for 6 h, and then dry at 40℃ overnight. Pulverize the dried product and heat at 130℃ for 5 h. Wash the product with pure water, collect the precipitate, dry, and pulverize to obtain the final modified oat flour.

[0005] Furthermore, the mixed enzyme mentioned in step (1) is a complex enzyme of α-amylase and glucanase, and the enzyme activity ratio of α-amylase to glucanase is 1:3.

[0006] Further, in step (1), the total enzyme activity of the mixed enzyme is 2.5-7.5 U / g.

[0007] Furthermore, in step (2), the concentration of the citric acid solution is 0.01-0.05 g / mL.

[0008] Furthermore, the centrifugation conditions are: centrifugation at 5000 rpm for 15 min; washing is performed by washing three times with pure water; drying is performed by drying at 40℃ for 12 h; and pulverization is performed by passing the powder through a 100-mesh sieve.

[0009] Further, in step (2), the pH of the citric acid solution is adjusted to 3.5; the ratio of the amount of enzymatically hydrolyzed oat flour to citric acid solution is 50g:100mL; and the mixing time is 5min.

[0010] On the other hand, an oat cereal powder prepared by the above method was proposed, with a Fourier transform infrared spectrum at 1744 cm⁻¹. -1 The peaks at the point are characteristic of ester bonds, which are formed through the esterification and cross-linking reaction of citric acid and oat starch molecules.

[0011] Furthermore, its water-holding capacity is greater than 150%, its clumping rate is less than 25%, and its glycemic index (EGI) is lower than the standard value calculated with white steamed buns as a reference.

[0012] Thirdly, an application of the above-mentioned oat cereal powder in the preparation of meal replacement foods, medical formula foods, and special foods for diabetic patients is proposed.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The method described in this invention significantly improves the reconstitution and digestibility of oat flour. The cereal flour prepared using this modification method effectively reduces the glycemic index (GI) and significantly reduces clumping during preparation. This process has strong industrial applicability, covering the entire health food sector from basic raw materials to finished products. Attached Figure Description

[0014] Figure 1 Fourier transform infrared spectrum of the oat cereal powder prepared according to the present invention; Figure 2 The water absorption rate of the oat cereal powder prepared in this invention; Figure 3 The clumping rate of the oat cereal powder prepared according to this invention; Figure 4 The brewing process of the oat cereal powder prepared according to the present invention; Figure 5 The in vitro hydrolysis curve of the oat cereal powder prepared in this invention; Figure 6 The EGI value is the oat cereal powder prepared according to the present invention. Detailed Implementation

[0015] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0016] This invention is based on the synergistic effect of enzymatic hydrolysis and acid modification. First, a specific enzyme controllably degrades oat starch granules, significantly enhancing their hydration capacity and dispersibility. This allows the starch in the oat flour to swell more uniformly and fully, effectively solving the problem of clumping during reconstitution. Then, citric acid, under heat treatment conditions, catalyzes cross-linking esterification reactions and structural rearrangements between starch molecules, constructing an anti-enzymatic hydrolysis network, increasing the content of resistant starch, and ultimately reducing the digestion rate and GI value. Simultaneously, citric acid and enzymatic modification further improve the uniformity of starch water absorption, further optimizing the clumping problem during reconstitution. This process, through the synergy of physical structural modification and chemical modification, simultaneously achieves dual optimization of product reconstitution properties and metabolic characteristics.

[0017] In the development of a mixed enzymatically hydrolyzed and citric acid-modified high-refillability, low-GI oat cereal powder, clumping rate and estimated glycemic index (EGI) were used as the core evaluation indicators. The clumping rate was quantified by weighing after refilling and sieving, reflecting the dispersibility of the powder; the EGI was calculated using an in vitro digestion simulation model combined with glucose release kinetics to predict the product's postprandial blood glucose response.

[0018] Comparative Example 1 Accurately weigh a certain amount of oat groats, soak and drain them, then dry them at 40℃ until the moisture content is about 10%. Then bake the oat groats at 130℃ for 20 minutes to complete the cooking process. After cooling to room temperature, grind them through a 100-mesh sieve and store them at 4℃ for later use.

[0019] Comparative Example 2 (Modified with Citric Acid) The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. 2.5 g of citric acid was weighed and dissolved in 60 mL of pure water, the pH was adjusted to 3.5, and the volume was brought to 250 mL. 50 g of cooked oat flour was weighed and added to 100 mL of 0.01 g / mL citric acid solution. The mixture was magnetically stirred for 5 min, and then spread evenly on a stainless steel tray. The mixture was equilibrated at room temperature for 6 h and then dried overnight in a 40 °C oven. The dried product was pulverized through a 100-mesh sieve and heated at 130 °C for 5 h. The product was washed three times with pure water, and the precipitate was collected and dried overnight in a 40 °C oven. The precipitate was then pulverized through a 100-mesh sieve to obtain the final product.

[0020] Comparative Example 3 (Modified with Citric Acid) The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. 12.5 g of citric acid was weighed and dissolved in 60 mL of pure water, the pH was adjusted to 3.5, and the volume was brought to 250 mL. 50 g of cooked oat flour was weighed and added to 100 mL of 0.05 g / mL citric acid solution. The mixture was magnetically stirred for 5 min, and then spread evenly on a stainless steel tray. The mixture was equilibrated at room temperature for 6 h and then dried overnight in a 40 °C oven. The dried product was pulverized through a 100-mesh sieve and heated at 130 °C for 5 h. The product was washed three times with pure water, and the precipitate was collected and dried overnight in a 40 °C oven. The precipitate was then pulverized through a 100-mesh sieve to obtain the final product.

[0021] Comparative Example 4 (Single Enzyme Digestion Modification) The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 2.5 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​of the volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0022] Comparative Example 5 (Single Enzyme Digestion Modification) The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 5.0 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​by volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0023] Comparative Example 6 (Single Enzyme Digestion Modification) The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 7.5 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​of the volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0024] Example 1 The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 2.5 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​of the volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0025] Weigh 2.5g of citric acid and dissolve it in 60mL of pure water, adjust the pH to 3.5, and bring the volume to 250mL. Weigh 50g of the above enzymatically hydrolyzed oat flour and add 100mL of 0.01g / mL citric acid solution. Mix magnetically for 5min, spread the mixture evenly on a stainless steel tray, equilibrate at room temperature for 6h, and dry overnight in a 40℃ oven. Grind the dried product through a 100-mesh sieve and heat at 130℃ for 5h. Wash the product three times with pure water, collect the precipitate, dry it overnight in a 40℃ oven, grind it through a 100-mesh sieve, and obtain the final product.

[0026] Example 2 The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 2.5 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​of the volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0027] Weigh 12.5g of citric acid and dissolve it in 60mL of pure water, adjust the pH to 3.5, and bring the volume to 250mL. Weigh 50g of the above enzymatically hydrolyzed oat flour and add 100mL of 0.05g / mL citric acid solution. Stir magnetically for 5min, spread the mixture evenly on a stainless steel tray, equilibrate at room temperature for 6h, and dry overnight in a 40℃ oven. Grind the dried product through a 100-mesh sieve and heat at 130℃ for 5h. Wash the product three times with pure water, collect the precipitate, dry it overnight in a 40℃ oven, grind it through a 100-mesh sieve, and obtain the final product.

[0028] Example 3 The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 5.0 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​by volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0029] Weigh 2.5g of citric acid and dissolve it in 60mL of pure water, adjust the pH to 3.5, and bring the volume to 250mL. Weigh 50g of the above enzymatically hydrolyzed oat flour and add 100mL of 0.01g / mL citric acid solution. Mix magnetically for 5min, spread the mixture evenly on a stainless steel tray, equilibrate at room temperature for 6h, and dry overnight in a 40℃ oven. Grind the dried product through a 100-mesh sieve and heat at 130℃ for 5h. Wash the product three times with pure water, collect the precipitate, dry it overnight in a 40℃ oven, grind it through a 100-mesh sieve, and obtain the final product.

[0030] Example 4 The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 5.0 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​by volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0031] Weigh 12.5g of citric acid and dissolve it in 60mL of pure water, adjust the pH to 3.5, and bring the volume to 250mL. Weigh 50g of the above enzymatically hydrolyzed oat flour and add 100mL of 0.05g / mL citric acid solution. Stir magnetically for 5min, spread the mixture evenly on a stainless steel tray, equilibrate at room temperature for 6h, and dry overnight in a 40℃ oven. Grind the dried product through a 100-mesh sieve and heat at 130℃ for 5h. Wash the product three times with pure water, collect the precipitate, dry it overnight in a 40℃ oven, grind it through a 100-mesh sieve, and obtain the final product.

[0032] Example 5 The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 7.5 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​of the volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0033] Weigh 2.5g of citric acid and dissolve it in 60mL of pure water, adjust the pH to 3.5, and bring the volume to 250mL. Weigh 50g of the above enzymatically hydrolyzed oat flour and add 100mL of 0.01g / mL citric acid solution. Mix magnetically for 5min, spread the mixture evenly on a stainless steel tray, equilibrate at room temperature for 6h, and dry overnight in a 40℃ oven. Grind the dried product through a 100-mesh sieve and heat at 130℃ for 5h. Wash the product three times with pure water, collect the precipitate, dry it overnight in a 40℃ oven, grind it through a 100-mesh sieve, and obtain the final product.

[0034] Example 6 The cooked oat flour prepared in Comparative Example 1 was used as the initial sample. A certain amount of cooked oat flour was weighed and dispersed in pure water at a material-to-liquid ratio of 1:4. The pH was adjusted to 4.8, and the mixture was magnetically stirred in a 50℃ water bath for 10 min. A mixed enzyme with a total enzyme activity of 7.5 U / g was added, and the mixture was enzymatically hydrolyzed at 50℃ and 150 rpm for 6 h. After the hydrolysis time was completed, anhydrous ethanol (12.5% ​​of the volume of the hydrolysate) was added to terminate the reaction. The hydrolysate was centrifuged at 5000 rpm for 15 min, the precipitate was collected, and washed three times with pure water. The resulting precipitate was dried at 40℃ for 12 h, pulverized, and passed through a 100-mesh sieve. It was then stored at room temperature for later use.

[0035] Weigh 12.5g of citric acid and dissolve it in 60mL of pure water, adjust the pH to 3.5, and bring the volume to 250mL. Weigh 50g of the above enzymatically hydrolyzed oat flour and add 100mL of 0.05g / mL citric acid solution. Stir magnetically for 5min, spread the mixture evenly on a stainless steel tray, equilibrate at room temperature for 6h, and dry overnight in a 40℃ oven. Grind the dried product through a 100-mesh sieve and heat at 130℃ for 5h. Wash the product three times with pure water, collect the precipitate, dry it overnight in a 40℃ oven, grind it through a 100-mesh sieve, and obtain the final product.

[0036] Experiment 7 (Fourier Infrared Spectroscopy) The sample was mixed with KBr at a ratio of 1:100 (w / w) until homogeneous, ground, and then pressed into a transparent thin film. Pure KBr powder was used as a blank control to subtract background. The test parameters were set as follows: scanning range 4000~500cm. -1 4cm resolution -1 Repeat the scan 32 times.

[0037] Depend on Figure 1 It can be seen that the cooked oat flour in Comparative Example 1 was at 1744 cm⁻¹ -1 There is a characteristic peak, which, since oats are oil-rich grains, is attributed to the stretching vibration of the carbonyl (C=O) group in the endogenous oils of oats. Figure 1 As shown in A, comparative examples 4-6, due to the washing process after enzymatic hydrolysis, removed some of the oil, resulting in a significant decrease in peak intensity. Conversely, from... Figure 1 A and Figure 1 As shown in B, the intensity of this characteristic peak in Comparative Examples 2-3 and Examples 1-6 exhibits a significant increasing trend. This strongly demonstrates that citric acid and starch molecules underwent an esterification cross-linking reaction, introducing new ester bonds. Simultaneously, with the increase in the degree of citric acid modification, its intensity at 1744 cm⁻¹... -1The peak intensity at the citric acid level also increased, indicating that the cross-linking reaction was enhanced with the increase in the degree of citric acid modification. This demonstrates that the modification method used in this invention can effectively achieve chemical modification of the oat starch molecular structure, and the infrared spectral characterization results are highly consistent with the changes in the modification gradient.

[0038] Experimental Example 8 (Water Absorption) Weigh 0.20 g (M1) of the sample into a 10 mL centrifuge tube and weigh it (M2). Add 4.0 mL of pure water, mix thoroughly on a vortex mixer for 5 min, let stand at room temperature for 30 min, then centrifuge at 3000 × g for 15 min, and discard the supernatant. Weigh the centrifuge tube and the precipitate, and record the weight as M3. The calculation formula is as follows: ; like Figure 2 As shown, the water absorption of the cooked oat flour in Comparative Example 1 was approximately 150%. In contrast, the single enzymatic hydrolysis, single citric acid modification, and composite modification involved in Comparative Examples 2-6 and Examples 1-6 all significantly improved its water absorption capacity. Citric acid modification (Comparative Examples 2-3): Citric acid introduces a large number of hydrophilic carboxyl groups through esterification grafting with starch, and the water absorption increases with the degree of modification. Enzymatic hydrolysis modification (Comparative Examples 4-6): Enzymatic hydrolysis locally digests the surface of starch granules, forming a rough morphology and microporous structure, and the resulting capillary effect enhances water absorption. However, excessive enzymatic hydrolysis may lead to micropore collapse, which in turn causes a decrease in water absorption. Composite modification (Examples 1-6): This method has the best water absorption performance. Citric acid diffuses into the interior of the granules through the enzymatically hydrolyzed micropores, causing the hydrophilic groups and capillary effect to work synergistically, further enhancing the water capture capacity. The static water absorption performance verified that the above modification method can significantly optimize the uniformity of water distribution and diffusion rate during the oat flour reconstitution process, thereby improving the reconstitution performance.

[0039] Experimental Example 9 Weigh 5.0 g (M1) of sample into a beaker, add 25 mL of boiling water, and stir along the inner wall of the beaker at an average speed of 120 rpm for 60 s using a glass rod. Filter the solution through a 20-mesh sieve (M2), rinsing the sieve once with deionized water. Dry the agglomerates and sieve in an oven at 105℃, then weigh the total weight of the sieve and agglomerates (M3) and calculate the agglomeration rate. The calculation formula is as follows: ; like Figure 3 and Figure 4As shown, the unmodified cooked oat flour in control group 1 exhibited severe clumping during brewing, with a clumping rate as high as 25%. In contrast, the three modification methods used in Comparative Examples 2-6 and Examples 1-6 significantly inhibited clumping. Regarding single citric acid modification (Comparative Examples 2-3), although it can alter the surface hydrophilicity of starch granules through acid treatment, the reduction was the most limited among the three methods. The introduction of citric acid resulted in limited expansion and delayed gelatinization of starch granules in the oat flour, allowing for a longer gelatinization time during brewing, thus enabling more complete starch expansion. Simultaneously, the citric acid groups enhanced the hydrogen bonding and electrostatic attraction between starch molecular chains, causing secondary aggregation of granules during brewing, leading to an increase in the clumping rate instead of a decrease. Regarding single enzymatic hydrolysis modification (Comparative Examples 4-6), pore formation on the granule surface improved dispersibility, but the clumping rate showed a significant upward trend with increasing enzymatic hydrolysis time, which is related to… Figure 2 The absorbency shown is related to the amount of water absorbed. Excessive enzymatic hydrolysis can lead to the collapse of the microporous structure of oat starch or particle breakage. Furthermore, the uneven distribution of micropores hinders the capillary migration of water between particles, thus inducing local aggregation and clumping. The composite modified group (Examples 1-6) exhibited the best synergistic anti-caking effect, especially under the conditions of low-concentration citric acid pretreatment combined with moderate enzymatic hydrolysis, which greatly enhanced the capillary effect of the cereal flour. This structural optimization allows brewing water to quickly and evenly penetrate into the internal matrix of the particles, improving the solubility and preparation quality of the oat flour.

[0040] Experimental Example 10 1. First, the total starch content in the sample was determined using a starch content kit. Based on the results, a sample containing approximately 100 mg of starch was weighed and placed in a beaker. 6 mL of distilled water was added and mixed thoroughly. The mixture was then heated in a boiling water bath for 10 min to gelatinize. After the solution cooled to 37°C, 5 mL of pepsin solution (3 U / mL) and 7 glass beads were added to simulate gastric peristalsis. The mixture was stirred in a 37°C water bath for 30 min. Subsequently, 8 mL of sodium acetate buffer (0.2 M, pH 5.2) and 5 mL of a complex enzyme solution (containing 290 U / mL α-amylase and 15 U / mL amylase) were added to initiate intestinal digestion simulation. 0.5 mL samples were taken at 0, 20, 60, 90, 120, and 180 min, and 4.0 mL of anhydrous ethanol was immediately added to terminate the enzyme reaction. Finally, the mixture was centrifuged at 6000 rpm for 10 min, and the supernatant was used to determine its glucose content using a GOPOD kit. The EGI value was calculated using the following formula: Where C represents starch content; C ∞ t represents the starch content at the maximum reaction time; t represents the reaction time. The reaction time is the end of the reaction; k is the reaction rate constant; AUC Y The area under the curve of glucose concentration versus time during sample digestion; AUC D The area under the curve of glucose concentration over time during the digestion of steamed buns refers to the glucose concentration; HI refers to the degree of glucose hydrolysis; EGI refers to the glycemic index.

[0041] like Figure 5 and Figure 6 As shown, the EGI value of the cooked oat flour in Comparative Example 1 was around 73, which is typical of a high-GI food. Different modification processes resulted in samples exhibiting different EGI values. After single-enzyme hydrolysis modification (Comparative Examples 4-6), the EGI values ​​of the samples significantly increased, showing an increasing trend with the degree of hydrolysis, with Comparative Example 5 reaching the highest value (approximately 85). This is because enzymatic hydrolysis disrupts the starch granule structure, increasing the specific surface area and providing more sites for enzymatic cleavage, thereby improving the digestion rate. Conversely, citric acid modification (Examples 1-6 and Comparative Examples 2-3) significantly reduced the EGI value to 59-68, transforming it into a medium-GI food, and the decrease increased with the degree of modification. This is mainly attributed to citric acid inducing the formation of cross-linked networks between starch molecules, physically blocking the diffusion of digestive enzymes; simultaneously, the grafted starch molecules produce a stronger steric hindrance effect, inhibiting the binding of starch chains to enzyme active sites. Furthermore, the uncrosslinked enzymatically hydrolyzed monocitric acid modified group (Comparative Examples 2-3) had a lower EGI than the composite modified group (Examples 1-6), possibly because its starch granules maintained higher density, thus exhibiting superior anti-digestion properties. Further comprehensive evaluation based on application indicators showed that Example 1 not only demonstrated the best reconstitution performance but also maintained an EGI value of around 64, successfully balancing excellent reconstitution experience with optimal anti-digestion performance, and was therefore identified as the optimal modified process group in this invention.

[0042] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing oat cereal powder that improves reconstitution properties and reduces GI, characterized in that: Includes the following steps, (1) Disperse cooked oat flour in pure water at a ratio of 1:4, adjust the pH to 4.8, and magnetically stir in a 50℃ water bath for 10 min. Add a mixed enzyme with a total enzyme activity of 2.5-7.5 U / g and enzymatically hydrolyze at 50℃ and 150 rpm for 6 h. After the enzymatic hydrolysis is completed, add 12.5% ​​anhydrous ethanol of the enzymatic hydrolysate volume to terminate the reaction. Centrifuge the enzymatic hydrolysate, collect the precipitate, wash, dry, and pulverize to obtain enzymatically hydrolyzed oat flour. (2) Mix the enzymatically hydrolyzed oat flour with a citric acid solution with a concentration of 0.01-0.05 g / mL, magnetically stir, spread the mixture on a tray, equilibrate at room temperature for 6 h, and then dry at 40℃ overnight. Pulverize the dried product and heat at 130℃ for 5 h. Wash the product with pure water, collect the precipitate, dry, and pulverize to obtain the final modified oat flour.

2. The preparation method for improving the reconstitution properties and reducing the GI of oat cereal powder according to claim 1, characterized in that, The mixed enzyme mentioned in step (1) is a complex enzyme of α-amylase and glucanase, and the enzyme activity ratio of α-amylase to glucanase is 1:

3.

3. The preparation method for improving the reconstitution properties and reducing the glycemic index of oat cereal powder according to claim 1, characterized in that, In step (1), the total enzyme activity of the mixed enzyme is 2.5-7.5 U / g.

4. The preparation method for improving the reconstitution properties and reducing the glycemic index of oat cereal powder according to claim 1, characterized in that, In step (2), the concentration of the citric acid solution is 0.01-0.05 g / mL.

5. The preparation method for improving the reconstitution properties and reducing the GI of oat cereal powder according to claim 1, characterized in that, The centrifugation conditions are: centrifugation at 5000 rpm for 15 min; washing is performed by washing three times with pure water; drying is performed by drying at 40℃ for 12 h; and pulverization is performed by passing the powder through a 100-mesh sieve.

6. The preparation method for improving the reconstitution properties and reducing the GI of oat cereal powder according to claim 1, characterized in that, In step (2), the pH of the citric acid solution is adjusted to 3.5; the ratio of the amount of enzymatically hydrolyzed oat flour to citric acid solution is 50g:100mL; and the mixing time is 5min.

7. An oat cereal powder prepared by the preparation method according to any one of claims 1-6, characterized in that, Fourier transform infrared spectrum at 1744 cm⁻¹ -1 The peaks at the point are characteristic of ester bonds, which are formed through the esterification and cross-linking reaction of citric acid and oat starch molecules.

8. The oat cereal flour according to claim 7, characterized in that, Its water-holding capacity is greater than 150%, its clumping rate is less than 25%, and its glycemic index (EGI) is lower than the standard value calculated with white steamed buns as a reference.

9. The use of the oat cereal powder according to claim 7 in the preparation of meal replacement foods, medical formula foods, and foods for diabetic patients.

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